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The Open Longevity Initiative Works Towards Organization of Trials

I noted the existence of the Open Longevity initiative earlier this month. This is an evolution of the core Russian-language longevity science community, involved in the Science for Life Extension Foundation and related advocacy initiatives. The members of that community have been building bridges to the European and US longevity science communities for a decade now, aided by progress in automated translation technologies and the growing prospects for therapies that can meaningful treat the causes of aging. Collectively, we've reached the point at which meaningful treatments are almost at the clinic; it is the time to move beyond talking to helping ensure that these treatments enter trials and become available as soon as possible.

Open Longevity is explicitly structured as an organization of patients, for patients: people who want to treat aging as the medical condition it is, and are willing to organize and participate in medical trials to push forward the state of the art. The present sad situation in medical regulation and the mainstream aging research community is that near all efforts that could be achieved now, this year, if people just went out and did the work, will never happen. No-one will test combinations of the non-chemotherapeutic senolytic drugs; no-one will try building a better polypill for reducing cardiovascular disease; and so on. Within the commercial and regulatory arena, the best that can be hoped for is narrow trials of a single drug candidate for the late stage of age-related disease, which is the goal that UNITY Biotechnology is aiming for with their senolytic treatments.

It is self-evident that better results than this can be achieved by ignoring the FDA and its Western European counterparts, given a bunch of people willing to put in the work and some funding, and who are sufficiently well organized to avoid the pitfalls of self-delusion that tend to beset more amateur citizen science efforts in medicine. Setting up responsible, transparent trials of treatments isn't rocket science, just hard work, and it certainly isn't something that only government organizations can achieve. I'm fairly certain that our broader community is capable of generating such an effort, I hope to see it happen in the years ahead in the matter of senolytic therapies, and indeed, I've written on this topic in past years.

The Open Longevity volunteers look like they are heading in the right sort of direction, for all that they are starting out with potential treatments that I'm not much in favor of spending time on - the standard panoply of calorie restriction mimetics and the like. Taking an incremental approach seems sensible, however, and it is developing the ability to organize and produce unbiased results that is important here, not the particular therapies used as the initial testbeds. Our community and the companies working on therapies have a great need for one or more organizations that can reliably deliver trials and medical tourism outside the present regulatory system as a service, and such an organization would help to greatly speed up progress towards widespread availability of the first rejuvenation therapies. On this note, the following turned up in my in-box earlier this week:

Starting on March 29th in Kotor, Montenegro, the first Longevity School is being held, organized by the patients' organization Open Longevity. The purpose of our organization is to carry out clinical trials of therapies against aging. We are determined to create the best possible therapies based on all achievements of science and considering individual approach. Recently we've started to organize clinical trials of a new type, based on the principles of openness, with a non-commercial approach, and aiming for continuous improvement of the effectiveness of interventions under trial. We believe that by not focusing on opportunities to capitalize the cure for old age, and by immediately publishing the results of clinical experiments, we will achieve a higher level of expertise. The protection of scientific advances by patents and trial data by secrecy leads to a lack of exploration of the potential reuse of existing therapies for new purposes, since it is impossible to ensure sufficient freedom to use the results.

The first task of the Longevity School in Montenegro is to raise the level of knowledge of the participating patients. For this matter, we will conduct 67 lectures on the biology of aging with a final exam. Our goal is to establish cooperation, a dialogue between patients, doctors, and scientists to achieve the common goal of radical life extension. Second, we will start testing a fasting mimicking diet, which aims to reduce the level of insulin-like growth factor 1 in humans. The third step is the preparation of clinical trials protocols for testing combinations of anti-aging interventions. We will have five roundtable discussions to come up with the best strategy. In doing so, our goal is not just to confirm or deny effectiveness of a drug or a combination of drugs. We will not stop at testing of a minor drug candidate like metformin. Our goal is to constantly increase the power of interventions, adapting it to the current situation and health conditions. That is why one of the tasks for Open Longevity project is to implement aging diagnostics into clinical practice.

The first Longevity School will be held from 29 March to 7 April. The Montenegro school is our first one, but we will systematically run Longevity Schools on all continents to engage millions of people into the common cause of life extension. We are moving from simple to complex, from diet to gene therapy, until aging is defeated.

Immune Cell Epigenetics Become More Disarrayed with Age

In this study, researchers note that at least some subsets of immune cells in older animals exhibit greater variability in gene expression (and thus behavior) than is the case in younger animals. At this point in the development of the work we can only speculate as to how this fits in to what is known of aging in general and aging in the immune system specifically. Is it a result of cells reacting to locally different levels of damage, or to secondary changes in cell signaling that vary more widely in older individuals because of molecular damage? Are the immune cells themselves relatively damaged, or does the presence of some damaged immune cells produce problems in communication and coordination across the whole population? These and other questions lack definitive answers at this time.

Researchers have shown that immune cells in older tissues lack coordination and exhibit much more variability in gene expression compared with their younger counterparts. We've all witnessed the progressive decline of function that comes with ageing, but what exactly causes this decline - and why does it happen at different rates for different parts of the body? To find answers, scientists need to unpick all of the mechanisms of ageing at the molecular level, for every tissue. This study focused on immune tissue: specifically, CD4+ T cells.

The immune system is like a symphony orchestra, with many different types and subtypes of cells working together to fight infections. But as the immune system ages, its response to infection weakens for reasons that are not yet clear. One long-standing debate amongst scientists concerns two central hypotheses: either the functional degradation is caused by a loss of cellular performance, or it is down to a loss of coordination among cells. To resolve the debate, scientists have studied many different cell types, analysing 'average' gene expression profiles. This study employed high-resolution single-cell sequencing technology to create new insights into how cell-to-cell variability is linked with ageing. The researchers sequenced the RNA of naïve and memory CD4+ T cells in young and old mice, in both stimulated and unstimulated states. Their findings clearly showed that loss of coordination is a key component of the impaired immune performance caused by T cell ageing.

"Imagine the immune system as a 'cell army', ready to protect the body from infection. Our research revealed that this army is well coordinated in young animals, with all the cells working together and operating like a Greek phalanx to block the infection. This tight coordination makes the immune system stronger, and allows it to fight infection more effectively. We show that as the animal gets older, cell coordination breaks down. Although individual cells might still be strong, the lack of coordination between them makes their collective effectiveness lower." Previous studies have shown that in young animals, immunological activation results in tightly regulated gene expression. This study further reveals that activation results in a decrease in cell-to-cell variability. Ageing increased the heterogeneity of gene expression in populations of two mice species, as well as in different types of immune cells. This suggests that increased cell-to-cell transcriptional variability may be a hallmark of ageing across most mammalian tissues.

Link: http://www.ebi.ac.uk/about/news/press-releases/ageing-cell-coordination-breakdown

The Aging of the Extracellular Matrix of the Heart

Researchers here look at the detailed impact of aging on the extracellular matrix of heart tissue. The extracellular matrix supports cells and its configuration and composition determines the physical properties of tissue. There are many issues that arise with aging in this structure, one of the most important of which is the cross-linking of matrix molecules by metabolic byproducts that are a challenge for the body to remove. Cross-links produce a reduction in tissue elasticity, among other changes, and in cardiovascular tissues this leads to hypertension, remodeling of the heart, and ultimately heart disease and death. Another important age-related issue in the extracellular matrix, one with the same ultimate outcome, is the growth of fibrosis. In this case the structure of the extracellular matrix is disrupted by the formation of scar tissue, something that occurs due to the progressive dysfunction of regenerative processes.

Age-related changes in cardiac homeostasis can be observed at the cellular, extracellular, and tissue levels. Progressive cardiomyocyte hypertrophy, inflammation, and the gradual development of cardiac fibrosis are hallmarks of cardiac aging. In the absence of a secondary insult such as hypertension, these changes are subtle and result in slight to moderate impaired myocardial function, particularly diastolic function. While collagen deposition and cross-linking increase during aging, extracellular matrix (ECM) degradation capacity also increases due to increased expression of matrix metalloproteinases (MMPs).

Of the MMPs elevated with cardiac aging, a number of studies have assessed MMP-9 in cardiac aging. There is strong evidence that MMP-9 is a major mediator for increased stiffness in the aging heart. In addition to proteolytic activity on ECM components, MMPs oversee cell signaling during the aging process by modulating cytokine, chemokine, growth factor, hormone, and angiogenic factor expression and activity. In association with elevated MMP-9, macrophage numbers increase in an age-dependent manner to regulate the ECM and angiogenic responses. Understanding the complexity of the molecular interactions between MMPs and the ECM in the context of aging may provide novel diagnostic indicators for the early detection of age-related fibrosis and cardiac dysfunction. One possible direction is to better understand how MMP activities could be modified to prevent or slow the development of excessive cardiomyocyte hypertrophy and ECM deposition. Aging is a resetting of baseline values to set a new homeostasis, and attempts to delay or prevent this shift may improve the cardiac aging phenotype.

Link: https://dx.doi.org/10.1007/s11357-017-9959-9

A Set of Recent Papers on Aspects of Cellular Quality Control in Aging

Autophagy is a prominent topic in aging research. This is also the case for other forms of cellular maintenance processes, but autophagy is by far the most studied and understood at this time. Here when I say autophagy I mean macroautophagy. There other other, less well cataloged forms, but it is usually the case that when someone refers to autophagy without qualification, then they are talking about macroautophagy. In this type of autophagy, damaged molecules and cell structures are isolated inside a specially constructed membrane, and that then fuses with one of the cellular recycling system known as lysosomes. A lysosome is packed with molecules capable of dismantling near all biological compounds it is likely to encounter, rendering them into raw materials for reuse.

All forms of quality control within cells appear to be quite influential in health and longevity over the long term. Damaged cellular components that linger cause secondary harms, and so the more efficiently they are removed the better the operation of the cell. Then multiply that by all the cells in a tissue. Unfortunately, cellular processes of repair and maintenance appear to succumb to forms of damage as the years pass. In the case of autophagy, one problem is caused by the accumulation of metabolic waste products that the lysosome is not equipped to handle. Lysosomes become bloated and unable to perform their normal tasks efficiently. Cells malfunction or die, and the waste products continue to build up in cells and cellular debris until they are visible as lipofuscin. This is how wear and tear proceeds in a self-repairing system: first the repair mechanisms start to fail, then everything else heads downhill ever more rapidly thereafter.

Beyond the varieties of autophagy, cells boast a panoply of other systems intended to fix problems and clear out unwanted junk, ranging from DNA repair to proteasomes to, as a last resort, encapsulating excess waste material and kicking it out into the space between cells. Not all are well understood. The few open access papers below cover some of this range, and are indicative of the level of attention given to cellular quality control in the medical research community. It isn't a coincidence that these papers focus on the brain and neurodegenerative conditions; that is where much of the academic funding for aging research is directed these days. Alzheimer's research alone accounts for a very large share of the public research funding directed towards aging as a whole, and it is plausible that private funding tends to mirror this distribution.

Dysregulation of Ubiquitin-Proteasome System in Neurodegenerative Diseases

The ubiquitin-proteasome system (UPS) is one of the major protein degradation pathways, where abnormal UPS function has been observed in cancer and neurological diseases. Many neurodegenerative diseases share a common pathological feature, namely intracellular ubiquitin-positive inclusions formed by aggregate-prone neurotoxic proteins. This suggests that dysfunction of the UPS in neurodegenerative diseases contributes to the accumulation of neurotoxic proteins and to instigate neurodegeneration. Here, we review recent findings describing various aspects of UPS dysregulation in neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and Huntington's disease.

DNA Damage Response and Autophagy: A Meaningful Partnership

Autophagy and the DNA damage response (DDR) are biological processes essential for cellular and organismal homeostasis. Herein, we summarize and discuss emerging evidence linking DDR to autophagy. We highlight published data suggesting that autophagy is activated by DNA damage and is required for several functional outcomes of DDR signaling, including repair of DNA lesions, senescence, cell death, and cytokine secretion. Uncovering the mechanisms by which autophagy and DDR are intertwined provides novel insight into the pathobiology of conditions associated with accumulation of DNA damage, including cancer and aging, and novel concepts for the development of improved therapeutic strategies against these pathologies.

Autophagy and Microglia: Novel Partners in Neurodegeneration and Aging

Autophagy is emerging as one of the core orchestrators of healthy aging. This self-degradation process is present in all mammalian cells and tissues, including the central nervous system (CNS), and specializes in directing unnecessary or damaged intracellular material to the lysosome, the major cellular organelle that digests and recycles all types of macromolecules. Autophagy, as a constitutive mechanism, participates in the basal turnover of long-lived proteins and organelles, playing a major role as a checkpoint for quality control. On the other hand, stressful situations such as metabolic starvation or functional damage induce an adaptive autophagic response to restore cellular homeostasis. Thus, adaptive autophagy provides the cell with nutrients and energy during metabolic shortage and relieves it from toxic components during functional damage. Accordingly, a correct completion of the autophagic response is central for optimal CNS physiology and the promotion of neuronal survival. This is evidenced by the elevated number of connections made between the dysregulation of autophagy, aging, and neurodegeneration.

In this review, we will describe the role of autophagy (dys)regulation in the aged and diseased brain. Particularly, we will focus on microglia, the brain's resident macrophages with intrinsic capability to respond to CNS damage, promoting repair and a correct brain function. First, we will briefly outline the process of autophagy and its regulation, and summarize key technical aspects for the correct monitoring of autophagy at the experimental level. Then we will review the role of autophagy in neurons and the impact of autophagy failure in neurodegeneration. Finally, we will detail the current state of the literature on the role of autophagy in peripheral macrophages and microglia, including the regulation of phagocytosis and the inflammatory response.

An Investigation of Declining Autophagy in Aging

Cellular quality control and maintenance processes such as autophagy are important to health and longevity. Unfortunately, like near all systems in our biology, they decline in effectiveness with advancing age, impacted by the accumulation of molecular damage that they cannot effectively deal with. This includes the hardy waste compounds making up lipofuscin, for example, which clutter up the recycling system of the lysosome in long-lived cells and degrade its operation. Researchers here survey some of the noteworthy quality control mechanisms and their failure over time in mice:

Sarcopenia and decreased cardiac function are common features of the decline in physical performance associated with aging. Sarcopenia refers to a loss of skeletal muscle mass that is accompanied by a decrease in muscle strength and increased fatigue. Aging in the heart is associated with pathological hypertrophy and thickening of the ventricle wall, leading to decreased cardiac output. Changes in both metabolism and macroautophagy, a lysosomal-dependent degradation process, have been associated with aging in both these tissues. These, in turn may contribute to the decline in function observed in these tissues during aging.

Macroautophagy, referred as autophagy in the remainder of this manuscript, is the most studied form of autophagic process. It involves the formation of double-membrane vesicles termed "autophagosomes", the sequestration of cytosolic substrate within autophagosomes, and the subsequent fusion of autophagosome and lysosome to form autophagolysosomes, where the engulfed macromolecules are degraded to provide substrates for cellular metabolism as well as damaged proteins and organelles to maintain cellular homeostasis. There is a tight connection between autophagy and life-span, as genetic manipulation to increase expression of specific autophagy genes in lower organisms promotes longevity. Autophagy-deficient mice also mimic several characteristics of age-related diseases, suggesting that autophagy is a key mechanism for protecting against cellular damage during aging. Furthermore, autophagy is a critical process for maintaining muscle and heart function, and tissue-specific impairment of autophagy in muscle and heart leads to sarcopenia and cardiomyopathy, respectively. Although there is evidence suggesting a potential role of autophagy in aging, the specific changes in basal levels of autophagy in skeletal and cardiac muscle during the natural aging process and the underlying mechanisms have not been well characterized.

Chaperone-mediated autophagy (CMA) is another type of autophagic process that specifically targets proteins that have a KFERQ amino acid recognition sequence for degradation. During CMA, target proteins are first recognized and bound by Hsc70. The resulting complex then is targeted to the lysosomes by binding to the lysosomal CMA receptor LAMP-2A, whereupon the target protein is unfolded and translocated into the lysosome for degradation. A decline of CMA during aging has been reported to occur in both the liver and central nervous system that is associated with decreased function; however, little is known about CMA in other tissues during aging.

Mitochondria are the key organelles for oxidative phosphorylation and ATP production. Mitochondria preferentially use fatty acid or glucose as energy sources depending on the availability of the type of fuel. The fuel selectivity by mitochondria also is subjected to hormonal regulation. During aging, cellular and metabolic stresses can increase generation of reactive oxygen species (ROS) that can damage mitochondria and lead to mitochondrial dysfunction, as well as perturb fuel utilization. Thus, mitochondrial quality control is critical for maintaining normal mitochondrial function and metabolism during aging. This quality control can be achieved by mitochondrial fusion, fission, and/or mitochondrial turnover through removal of damaged mitochondria by autophagy (mitophagy) and concomitant biosynthesis of new mitochondria. Currently, little is known about the changes in mitochondrial quality control and relevant metabolites that occur in aged muscle and heart.

In this study, we systematically examined and compared the markers for autophagy, CMA, and mitochondrial quality control in skeletal and cardiac muscle isolated from young and aged mice, as well as performed metabolomics profiling of acylcarnitines, amino acid and ceramides. Our studies confirm that autophagy declines in both the muscle and heart during aging, although the mechanism for the impairment in autophagy appears to be different between these tissues. Furthermore, there are decreased markers for CMA and mitochondrial quality control in the muscle whereas they are unchanged in the heart. The fuel preference and metabolism are differentially altered in these two tissues during aging, with skeletal muscle from aged mice showing a metabolomic signature suggestive of insulin resistance and fatty acid fuel inflexibility whereas the heart exhibited decreased fatty acid β-oxidation. These differential effects in muscle and heart metabolism during aging suggest that different types of metabolic derangements may occur in muscle vs. heart, and thus may require different therapeutic approaches to optimize the function of these two tissues during aging and aging-associated diseases.

Link: http://dx.doi.org/10.18632/aging.101181

Proposing that CK2.3 Treatment Can Restore Bone Density in Osteoporosis

Two populations of cells work on maintaining bone tissue; osteoclasts break down bone, while osteoblasts build it up. There is a constant dynamic process of remodeling underway in which both cell populations participate. Unfortunately, the balance between creation and destruction runs awry in aging, with an ever greater deficit in the creation of bone tissue. This leads to a progressive loss in bone density and the development of osteoporosis: bones become ever more brittle and fragile. A number of existing and potential treatments attempt to override the activity of osteoclasts or osteoblasts, restoring the balance without addressing the root causes of the change. Here, researchers use modeling to propose that one such treatment could in theory be used to restore the bones of osteoporosis patients to a healthy density. The proof of that remains to be accomplished, however.

They may seem rigid and set in their ways, but your bones are actually under constant construction and deconstruction. They give up their nutrient treasures (calcium) to the body and then rebuild in a constant give-and-take sort of rhythm. When that rhythm shifts with advancing age or the onset of osteoporosis, the rebuilding process decreases. Bones lose density and strength and become more prone to fracture. Now researchers have applied mathematical modeling expertise to biological inquiry in order to point the way to a promising remedy. The biologist has shown that treating a mouse with a peptide known as CK2.3 increases bone mineral density. The mathematician has calculated estimated dosages for human beings. According to their model, injections of CK2.3 can raise bone mineral density of bones badly degraded by osteoporosis back to healthy levels.

Bone mineral density is affected by two processes: bone formation and bone degradation. Current drug treatments, especially bisphosphonates, address the cells involved in bone degradation (osteoclasts). Only the approved drug parathyroid hormone (PTH) addresses the cells involved in bone formation (osteoblasts) but doctors must prescribe bisphosphonates with it to target bone degradation simultaneously. The peptide used in this research - CK2.3 - is the only one that decreases bone degradation while simultaneously increasing bone formation.

One team designed the mimetic peptide CK2.3 and showed that it increased bone mineral density in a mouse model by blocking the CK2 protein's interaction with the BMPR1a protein - an interruption that allows the cells that form new bone (osteoblasts) to increase. Subcutaneous (below the skin) injection increased bone formation in the crown of the skull (known as calvaria), while systemic injection decreased bone degradation and increased bone mineral density. The other team used that information to calculate ideal dosages for healthy humans and those with osteoporosis. A mouse and a human are different in many ways, so calculating a dosage is more complex than just adjusting for differences in weight. Researchers developed part of the model using the concepts in physiology-based pharmacokinetic (PBPK) models. Such models can be used to calculate how a pharmaceutical molecule distributes in different parts of the body. In this case, the researchers needed to know what the local concentration of CK2.3 would be at the site where bone is formed. Once this was determined, another math model was used to calculate bone mineral density.

Link: http://www.udel.edu/udaily/2017/march/modeling-osteoporosis-treatment/

Reassessing Past Evidence for Radiation Hormesis to Extend Life in Dogs

It is well known that induction of low or intermittent levels of repairable damage in cells and tissues is a good thing. It triggers more aggressive cellular maintenance for some period of time, and the end result is a net gain in the quality of the cellular environment: fewer damaged proteins and structures left to cause secondary issues. This effect is known as hormesis, and most common forms of molecular damage and stress to cells can trigger it. Exercise and calorie restriction produce hormetic effects, for example, as does exposure to heat and to most toxins at suitably low doses. Of interest for today is the hormesis produced by exposure to low levels of ionizing radiation, a process that has been studied in insects and to a lesser degree in short-lived mammals.

The next step after research involving short-lived mammals is to run studies in longer-lived mammals. The cost of such studies increases dramatically with species life span, which is why the history of any particular subject in the life sciences starts with worms and flies, works up to mice, and only then reaches dogs, pigs, and primates before clinical translation to human medicine. At each stage, compelling results are needed to raise the funding for the next and more expensive set of work. The large amount of data on various methods of modestly slowing aging in this range of species has made it quite clear that a given method becomes dramatically less effective in species of longer life spans. Calorie restriction can add 40% to the life span of mice, but certainly doesn't do that in humans. Life span in our species is much less plastic in response to environmental circumstances and genetic alterations known to impact health and longevity than is the case in flies, worms, and mice.

In the paper noted below, researchers reassess the effects of radiation hormesis in a comparatively short-lived breed of dogs, in both younger and older individuals. The data they use was originally generated in the late 1980s. They claim a gain of remaining life expectancy of 15% or so in older dogs, and 50% or so in younger dogs. The size of the study is not enormous, so I'd certainly like to see that result replicated. The outcome is unexpectedly, even suspiciously large for a hormesis effect in a mammalian species of this life span.

The authors state that the original studies controlled well for confounding variables, but given that they ran in the 1980s, I think it quite plausible that those researchers did not adequately control for calorie restriction effects. This is a major issue with many of the life span studies conducted prior to the turn of the century, and even a sizable fraction of those carried out later. I looked through one of the referenced documents that discussed the experimental protocols, and didn't find any mention of diet there. So I don't think that this paper means we should all be getting low-intensity ionizing radiation sources for our bedrooms - the evidence would have to be far more extensive and bulletproof to start making that sort of suggestion. Taken together with the other animal evidence, however, it does indicate that the present zero tolerance approach to radiation exposure is probably mistaken.

Evidence That Lifelong Low Dose Rates of Ionizing Radiation Increase Lifespan in Long- and Short-Lived Dogs

The overall effects of ionizing radiation on organisms are well known at high doses. At high and low doses, the detailed cell response mechanisms are complicated and may involve all levels of biological organization. About 75% of the human body is water, and a principal effect of radiation is the creation of reactive oxygen species (ROS), including hydrogen peroxide. They are a double-edged sword. Depending on their concentrations, they may cause damage or signaling in terms of stress responses. Studies on experimental living systems and on humans have shown, depending on the individual genome, that low doses of radiation upregulate many biological protective mechanisms, which also operate against nonradiogenic toxins and produce beneficial effects, including a lower risk of cancer.

For more than a century, extensive studies have been carried out on the effects of radiation, which demonstrate that harmful effects, such as radiation illness, may arise after exposures above known threshold dose levels, whereas a range of beneficial effects may be observed following low-dose exposures. Although there appears to be an awareness among the prominent leaders of the radiation protection establishment that current radiation protection policy contradicts this biological evidence; there is a very broad consensus among them that it is impossible to attribute health effects to low radiation exposures, namely to exposures similar to the wide spectrum of background levels. This opinion does not consider the recent progress in biological research on the mechanisms that underlay the fact that living organisms are "complex adaptive systems."

When people increasingly question whether low levels or low doses of radiation are really harmful, protection practitioners argue that "radiation-sensitive individuals" exist who are more vulnerable than average people to potential "health effects" and must be protected. This concern about protecting sensitive individuals and the suggestion that longevity may be the most appropriate measure of the effect of radiation on health led to this examination of the effect of dose rate on the lifespans of dogs. The authors reexamined data on the health effects of long-term irradiations in two large-scale studies on groups of beagle dogs. One exposed the dogs to whole-body cobalt-60 γ-radiation. The other evaluated dogs whose lungs were exposed to α-particle radiation from plutonium. Each group of dogs received a different dose rate.

These studies had been reviewed previously to determine the dependence of the lifespan of 50% mortality dogs on dose rate. The lifespans of dogs at 5%, 10%, and 50% mortality in the control group (background dose rate) were compared with the lifespans of the 5%, 10%, and 50% mortality dogs in each dose rate group. Analysis of the data of the first study suggested an increase in the lifespan of dogs exposed to 50 mGy of γ-radiation per year, compared to the control dogs. Analysis of the data of the second study suggested an increase in longevity for dogs with an initial plutonium lung burden of 0.1 kBq/kg, compared to the control dogs. These are very credible studies, carefully carried out by qualified and experienced scientists who bred the dogs and controlled all confounding factors. Interpolations of the study data suggest that the optimum dose rate for longevity is about 50 mGy per year for all mortality levels. The lifespan increase is about 15% for 50% mortality dogs and much greater for the more radiation-sensitive dogs. The shorter lived control dogs (5% mortality level) have a lifespan of about 3000 days, whereas the dogs in the group with an initial plutonium lung burden of 0.16 kBq/kg have a lifespan of about 4500 days, 50% longer.

If dogs model humans, then one should expect that radiation-sensitive individuals would benefit more from exposures to low-level radiation than average humans. So protecting sensitive people from low-dose γ- or α-radiation would be inappropriate because it would deprive them of the health benefit of a longer life. The results of this review suggest the need to change radiation protection policy. Obviously, maintaining exposures as low as reasonably achievable is very likely detrimental.

The Current State of Senolytic Drug Candidates

Here, find an examination of the current state of senolytic drug candidates, compounds capable of selectively destroying senescent cells. All of those established by the research community appear to work by provoking lingering senescent cells into taking the final steps into apoptosis and self-destruction. Near all senescent cells in fact undergo apoptosis on their own, or are destroyed by the immune system. The few that remain seem primed for apoptosis, but are held back by a small number of inhibitor mechanisms. Drugs that target those mechanisms have been shown to clear up to 50% of senescent cells from aged tissues, the actual amount varying widely by tissue and drug type - in some tissues, the effect is negligible for the drugs tried to date.

The accumulation of senescent cells with age is one of the root causes of degenerative aging and age-related disease. These cells secrete a harmful mix of signals that promote inflammation, disorder extracellular matrix structures required for correct tissue function, and encourage bad behavior in nearby normal cells. In older individuals, this becomes a significant driver of the damage of aging. The most straightforward approach to this problem is to remove these unwanted cells; they are only a fraction of most tissues, and so can be safely cleared out. Studies in mice have demonstrated an extension of healthy life and reversal of aspects of aging through the use of senolytic therapies; it is an exciting field.

Aging at the cellular level is called "cell senescence", and it contributes profoundly to whole-body aging. The most promising near-term prospects for a leap in human life expectancy come from drugs that eliminate senescent cells. Programs in universities and pharmaceutical labs around the world are racing to develop "senolytic" drugs, defined as agents that can kill senescent cells with minimal harm to normal cells.

By analogy with chemotherapy for cancer, the value of a senolytic treatment is measured by its ability to kill senescent cells without doing harm to normal cells. The index called SI50 (SI for "selectivity index - 50%") is defined by analogy to LD50, the "lethal dose" of a toxin, the dose at which half of all cells die. SI50 is defined as the ratio of LD50 for normal cells and LD50 for senescent cells. It is the concentration of the agent at which half the normal cells die, divided by the concentration at which half the senescent cells die. A recent study in which researchers killed senescent cells by interfering in the crosstalk between FOXO4 and P53 reported an SI50 about 12. My guess is that 12 is an encouraging beginning, but it is not high enough to support a useful therapy.

The encouraging fact is that, at the optimal dose, more than 80% of the senescent cells have succumbed to apoptosis, while the number of eliminated normal cells is still below detection. Unfortunately, senolytic agents studied previously, including dasatinib, quercetin and ATTAC, did not include measurements of SI50 that we might use for comparison. The authors of the FOXO4 study were in a rush to publish. They used a fast-aging strain of mice, and even for these, they did not wait to see survival curves. The indicatators of rejuvenation that they do report look positive: increased activity levels, regrowth of lost fur, and improvement of kidney function lost with age.

I had missed the two papers about senolytic drug candidates ABT-263 and ABT-737. Both ABT-263 and ABT-737 were identifed in screens for agents that block BCL-2. BCL-2 is the founding member of another family of proteins that signal a cell to resist apoptosis. The ABT-263 paper included some in vivo results, indicating enhanced growth of blood stem cells after senescent cells have been removed. In vivo testing of ABT-737 was limited. Neither group reports the selectivity index (SI50), but from graphs that they do present, it is clear that ABT-263 is more selective than ABT-737, and that neither is as selective as the more recent FOXO4 method.

The idea of removing senescent cells has a lot of appeal, and enjoys broad empirical support in mammals. There is now a world-wide effort, making rapid progress toward specificity in senolytic treatments. The FOXO4 approach involves the newest agent, and it shows the best ratio yet for killing senescent cells while avoiding collateral damage to healthy cells. It cannot be taken orally and must be injected, but perhaps this is not such a drawback for a treatment that is needed only intermittently, every few years. How will such promising mouse results translate into human health and life extension? We have as yet no data, not even anecdotes. But perhaps we are near the point where hope and courage will motivate the first self-experimenting volunteers. This is a fast-moving field in which researchers are in a rush to publish and (presumably) pharmaceutical companies are taking pains to keep their results hushed up. Sharing of information and resources could push this research over the top and give us the first full decade of human life extension.

Link: https://joshmitteldorf.scienceblog.com/2017/03/28/senolytics-against-aging-snapshot-of-a-fast-moving-field/

A Look at Some Recent Efforts to Push Rapamycin Derivatives to the Clinic

Rapamycin, its derivatives such as everolimus, and the cellular biology directly affected by this class of drug continue to be of interest to that part of the aging research community focused on modestly slowing the progression of aging. The regulatory situation in the US makes it far from straightforward to move matters towards clinic applications for aging, however, even putting aside the usual technical challenges and side-effect issues inherent in this sort of drug development. This is illustrated in the following popular science article:

Can a pill make you younger? One of the few drug studies ever carried out in an attempt to address this question was reported by Novartis on Christmas Eve 2014. The company had sought to see whether giving low doses of a drug called everolimus to people over 65 increased their response to flu vaccines. It did, by about 20 percent. Yet behind the test was a bigger question about whether any drug can slow or reverse the symptoms of old age. Novartis's study on everolimus, which looked at whether the immune system of elderly people could be made to act younger, has been called the "first human aging trial."

Last week a Boston company, licensing two drug molecules, and the right to use them against aging-related disease, from Novartis and making the research the basis of a startup company, resTORbio. The company says it will further test whether such drugs can rejuvenate aged immune cells. The drug Novartis tested is a derivative of rapamycin, a compound first discovered oozing from a bacterium native to Easter Island, or Rapa Nui, and named after it. Thanks to its broad effects on the immune system, rapamycin has already been used in transplant medicine as an immune suppressant.

What's even more interesting about rapamycin, however, is its reputation as the most consistent way to postpone death, at least in laboratory species. It lengthens the lives of flies, worms, and rodents, too. Feed the compound to mice and they live 25 percent longer, on average. A study is under way in Seattle to see if rapamycin extends the lives of pet dogs. What we don't have yet are formal studies of whether rapamycin or any other drug can lengthen people's life spans. For many reasons, companies haven't been keen to pursue potential anti-aging treatments. Scientifically, longevity pills remain an outré idea, the domain of cranks and quacks. Clinically, it's difficult to prove a drug extends life, as it would take too long. Regulation-wise, there's no clear path forward, as aging hasn't generally been recognized as a disease you can treat. But recently, venture capitalists who used to run from such ideas have begun investing.

Brian Kennedy, who researches aging at the Buck Institute, says the Novartis study was "groundbreaking" because of how it found a way to address the drug's impact on the effects of age. "No one has the stomach to do longevity studies. Or you can do what Novartis did, which is to choose a property of aging and see if you can slow it down." Novartis says it will soon be reporting more results from its studies in the elderly. But the company also decided that the research did not fit its priorities. "We will stop developing it for aging-related disorders. It's outside of our current strategy." The resTORbio startup will try to use the Novartis drugs to reverse what it calls "immunosenescence," or detrimental changes to the immune system that occur with age. In part, that might include trying to restore certain types of T cells, which become exhausted and don't remain vigilant against cancer and infections.

Link: https://www.technologyreview.com/s/603997/is-this-the-anti-aging-pill-weve-all-been-waiting-for/

Regulatory Processes Relevant to Amyloid Formation in Aging

The open access paper for today takes a look at amyloid formation and some of the cellular processes that try to hold it back, processes that become increasingly disarrayed with advancing age. Amyloids are one of the distinguishing features of old tissues, absent in the tissues of younger individuals. There are a score or so of different types of amyloid, each corresponding to a particular protein that can become misfolded in a way that makes it precipitate and clump into solid aggregates between cells. Some amyloids are very well associated with specific age-related diseases, as is the case for amyloid-β and Alzheimer's disease, and as is becoming the case for transthyretin amyloid and cardiovascular disease. Others remain more obscure, and it is even possible that some do not contribute meaningfully to aging over a normal human life span.

In those cases where the biochemistry of an amyloid is well explored, as for amyloid-β, it appears that it is not the amyloid per se that is the problem, but the surrounding halo of related compounds. This environment and its interactions with cells has proven to be exceedingly complex, like most areas of interest to modern medicine. Clearing out the amyloid should nonetheless be beneficial, either by removing a source of those errant and damaging molecules, or by damping the reaction of cells to its presence, something that may also be a problem. Not all cellular reactions to the damage and change of aging are beneficial: there are plenty of examples of antagonistic pleiotropy to pick from, in which cellular behavior that helps in the context of a youthful environment is far less benign in the context of aged tissues.

Even before attaining a complete understanding of the biochemistry of any particular amyloid, a task that the Alzheimer's research community has demonstrated to be very challenging, we should be guided towards a strategy of removal. This is on the basis that amyloid is not observed in any significant amount in young tissues. The high level strategy for the development of rejuvenation therapies should be to target and revert known changes, at least in those cases where we can put forward good evidence for the change to occur due to the normal operation of metabolism. In other words that it may be a root cause of aging, not secondary to some other change. Amyloid accumulation appears a good candidate in this model, though given the complexity and still incomplete mapping of the mechanisms involved, the definitive proof will probably arrive from successful clearance rather than successful analysis.

Cellular Regulation of Amyloid Formation in Aging and Disease

As the population is aging, the incidence of age-related neurodegenerative diseases, such as Alzheimer and Parkinson disease, is growing. The pathology of neurodegenerative diseases is characterized by the presence of protein aggregates of disease specific proteins in the brain of patients. Under certain conditions these disease proteins can undergo structural rearrangements resulting in misfolded proteins that can lead to the formation of aggregates with a fibrillar amyloid-like structure. The role of these aggregates in disease is not fully understood: the most prevalent hypothesis is that aggregation intermediates - single or complexes of aggregation-prone proteins - are toxic to cells and that the aggregation process represents a cellular protection mechanism against these toxic intermediates.

Cells have a protein quality control (PQC) system to maintain protein homeostasis. Preserving protein homeostasis involves the coordinated action of several pathways that regulate biogenesis, stabilization, correct folding, trafficking, and degradation of proteins, with the overall goal to prevent the accumulation of misfolded proteins and to maintain the integrity of the proteome.

One of the cellular mechanisms that copes with misfolded proteins is the chaperone machinery. A molecular chaperone is defined as a protein that interacts with, stabilizes or assists another protein to gain its native and functionally active conformation without being present in the final structure. In addition to folding of misfolded proteins, molecular chaperones are also involved in a wide range of biological processes such as the folding of newly synthesized proteins, transport of proteins across membranes, macromolecular-complex assembly or protein degradation and activation of signal transduction routes. Next to their function under normal cellular conditions, chaperones play an important part during neurodegeneration when there is an overload of the PQC system by unfolded proteins. Each neurodegenerative disease is associated with a different subset of chaperones such as heat shock proteins that can positively influence the overload of unfolded proteins

Protein degradation is another key mechanism to deal with misfolded proteins. Three pathways have been described, i.e., the ubiquitin-proteasome system (UPS), chaperone mediated autophagy (CMA), and macroautophagy. Protein aggregates or proteins that escape the first two degradation pathways are directed to macroautophagy, a degradation system where substrates are segregated into autophagosomes which in turn are fused with lysosomes for degradation into amino acids. The proteins involved in neurodegenerative disease can rapidly aggregate and can thereby escape degradation when they are still soluble, the aggregates and intermediate forms are partly resistant to the known degradation pathways.

A further compensatory mechanisms involves the endoplasmic reticulum (ER). The unfolded protein response (UPR), induced during periods of cellular and ER stress, aims to reduce unfolded protein load, and restore protein homeostasis by translational repression. ER stress can be the result of numerous conditions, including amino acid deprivation, viral replication and the presence of unfolded proteins, resulting in activation of the UPR. In addition, misfolded proteins can be sequestered in distinct protein quality control compartments in the cell by chaperones and sorting factors. These compartments function as temporary storage until the protein can be refolded or degraded by the proteasome. Different compartments have been described in the literature that sequester different kind of misfolded proteins at various conditions.

Under normal conditions, the PQC can rapidly sense and correct cellular disturbances by activating stress-induced cellular responses to restore the protein balance. During aging or when stress becomes chronic, the cell is challenged to maintain proper protein homeostasis. Eventually, this can lead to chronic expression of misfolded and damaged proteins in the cell that can result in the formation of protein aggregates. The presence of aggregation-prone proteins contributes to the development of age-related diseases. The decline of protein homeostasis during aging is a complex phenomenon that involves a combination of different factors. In line with the decreased protein homeostasis, there appears to be an impairment of the upregulation of molecular chaperones during aging. Since all major classes of molecular chaperones, with the exception of the small heat shock proteins, are ATPases it has been suggested that the depletion of ATP levels during aging due to mitochondria dysfunction would affect their activity. This is reflected by the repression of ATP-dependent chaperones and the induction of ATP-independent chaperones in the aging human brain. This may contribute to the decline of chaperoning function during aging.

Under the right conditions any protein could form amyloid-like structures. Although amyloids have been traditionally related to diseases, they also have diverse functions in organisms from bacteria to human that may underlie their nature. Nevertheless, the toxicity of amyloid intermediate species associated with disease makes protein aggregation a process that has to be under tight control and regulation. In this context, aging is a key risk factor due to the progressive decline of protein homeostasis, which leads to increased protein misfolding and aggregation. This can eventually result in the onset of age-related diseases characterized by protein aggregation. As the human population becomes older, it is essential to understand the processes underlying age-related diseases that are the result of protein aggregation and its associated toxicity. This is a very broad research field, ranging from biophysics to clinical trials. Every year discoveries are made that involve the identification of factors affecting protein aggregation. It can be concluded that the overall knowledge of the aggregation process is improving, which will allow for the development of new and accurate treatments against aggregation-linked diseases.

An Examination of Mitochondrial Dysfunction in Senescent Cells

Researchers here review what is known of mitochondrial dysfunction in cellular senescence. Senescent cells accumulate with age, and their growing presence is one of the contributing causes of degenerative aging. Some fraction of the damaging behavior of these cells, particularly their ability to generate chronic inflammation, may be driven by failing mitochondria, but there is the question of the ordering of cause and consequence here: does the state of cellular senescence tend to produce cells populated by damaged mitochondria, or is the sort of mitochondrial DNA damage outlined in the SENS view of aging causing cellular senescence? Both cases seem to occur, but knowing that much doesn't tell us which is more important. Further, mitochondria have important roles to play in the normal progression of cellular senescence: this is a state in which most such cells self-destruct via apoptosis, a process of programmed cell death in which mitochondria play a core role. The situation in which senescent cells start down the path to apoptosis but fail to self-destruct is the interesting one, both for the contribution to aging, and for what the mitochondria might be doing in that pathological situation.

Senescent cells accumulate with age in a wide range of tissues. The rate of accumulation of senescent cells in liver and intestinal crypts predicts median and maximum lifespan of mice in cohorts with widely different aging rates. More importantly, interventions that selectively ablate senescent cells by genetic and/or pharmacologic means may improve healthspan and lifespan in mice. Mechanistically, the age-promoting effects of senescence are associated with the restriction of regenerative capacity of stem and progenitor cells as well as the secretion of bioactive molecules (the so-called senescence-associated secretory phenotype, SASP), specifically pro-inflammatory and matrix-modifying peptides. Pro-aging effects of senescent cells are aggravated by SASP and, possibly, other paracrine mediators which can propagate senescence from cell to cell as a bystander effect. In recent years, evidence has been mounting that senescent cells impact on their environment via yet another principal pathway: mitochondrial dysfunction.

Along with cell senescence, mitochondrial dysfunction is another essential 'hallmark of aging', and the two have been independently identified as important drivers of aging. Importantly, they are closely interlinked: mitochondrial dysfunction drives and maintains cell senescence, while at the same time cell senescence, specifically persistent DNA damage response signalling, directly contributes to Senescence-Associated Mitochondrial Dysfunction (SAMD). Despite the close interdependent relationship between senescence and SAMD, the true complexity of these interactions and their role in aging remains to be elucidated. For example, it is currently unclear how much of the mitochondrial dysfunction that has been observed at tissue level during aging is actually associated with senescence at a cellular level. Furthermore, despite its central contribution to the senescent phenotype, it is not clear how mitochondria become dysfunctional in senescence.

An important question is to what extent aging-associated mitochondrial dysfunction and cell senescence/SAMD are interrelated. Does aging-related mitochondrial dysfunction cause senescence in vivo or vice versa? Is mitochondrial dysfunction in aging actually a mosaic phenomenon, occurring preferentially or exclusively in the senescent cells? Given the high prevalence of senescent cells in many tissues, this appears highly possible. Emerging data suggest that it is SAMD rather more than general loss of mitochondrial function in aging that reduces homeostatic capability, causing compromised responses to peak energy demand and driving metabolic insufficiency in aging. For instance, we have found that SAMD in hepatocytes (and other cell types) includes a compromised capacity to metabolize fatty acids, which causes lipid storage in aging liver and thus contributes to fatty liver (steatosis), a common and pathologically significant complication of liver aging. Adipocyte senescence is an essential driver of adipose tissue dysfunction and obesity, and this link is very probably mediated by SAMD. Analysing mitochondrial dysfunction in aging tissues at single-cell resolution in combination with interventions that selectively ablate senescent cells will enable a better understanding of the importance of SAMD in aging.

Link: http://www.ebiomedicine.com/article/S2352-3964(17)30116-0/fulltext

A Lightning Tour of One Arm of the Longevity Science Community

This popular press article covering one arm of the longevity science research community in the US is better than most, in that it seems moderately accurate when it comes to identifying some of the people who matter and a few of their views on the topic. Of course in any such article you are flying over the terrain at a great height, seeing only the mountaintops, and little of what really makes the place live and breathe. You are also missing the other regions you cannot see. My chief complaint here is unfortunately a typical one, in that the author presents the SENS rejuvenation research program in a fairly disingenuous way. This is no way to treat the class of research and development most likely to turn back aging in the near future.

For decades, the solution to aging has seemed merely decades away. In the early nineties, research on C. elegans, a tiny nematode worm that resembles a fleck of lint, showed that a single gene mutation extended its life, and that another mutation blocked that extension. The idea that age could be manipulated by twiddling a few control knobs ignited a research boom, and soon various clinical indignities had increased the worm's life span by a factor of ten. Death would no longer be a metaphysical problem, merely a technical one. The celebration was premature. Gordon Lithgow, a leading C. elegans researcher, told me, "At the beginning, we thought it would be simple - a clock! - but we've now found about five hundred and fifty genes in the worm that modulate life span. And I suspect that half of the twenty thousand genes in the worm's genome are somehow involved."

For us, aging is the creeping and then catastrophic dysfunction of everything, all at once. Our mitochondria sputter, our endocrine system sags, our DNA snaps. Our sight and hearing and strength diminish, our arteries clog, our brains fog, and we falter, seize, and fail. Every research breakthrough, every announcement of a master key that we can turn to reverse all that, has been followed by setbacks and confusion. A few years ago, there was great excitement about telomeres, DNA buffers that protect the ends of chromosomes just as plastic tips protect the ends of shoelaces. As we age, our telomeres become shorter, and, when these shields go, cells stop dividing. If we could extend the telomeres, the thinking went, we might reverse aging. But it turns out that animals with long telomeres, such as lab mice, don't necessarily have long lives - and that telomerase, the enzyme that promotes telomere growth, is also activated in the vast majority of cancer cells. The more we know about the body, the more we realize how little we know.

In the murk of scientific inquiry, every researcher looks to a ruling metaphor for guidance. Aubrey de Grey likes to compare the body to a car: a mechanic can fix an engine without necessarily understanding the physics of combustion, and assiduously restored antique cars run just fine. De Grey is the chief science officer of Silicon Valley's SENS Research Foundation, which stands for Strategies for Engineered Negligible Senescence - a fancy way of saying "Planning Your Comprehensive Tune-up." De Grey has proposed that if we fix seven types of physical damage we will be on the path to living for more than a thousand years. "Gerontologists have been led massively astray by looking for a root cause to aging, when it's actually that everything falls apart at the same time, because all our systems are interrelated. So we have to divide and conquer." We just need to restore tissue suppleness, replace cells that have stopped dividing and remove those that have grown toxic, avert the consequences of DNA mutations, and mop up the gunky by-products of all of the above. If we can disarm these killers, de Grey suggests, we should gain thirty years of healthy life, and during that period we'll make enough further advances that we'll begin growing biologically younger. We'll achieve "longevity escape velocity."

De Grey vexes many in the life-extension community with his prophetic air of certainty. His 2007 book, "Ending Aging," is replete with both exacting research into the obstacles to living longer and proposed solutions so ambitious that they resemble science fiction. De Grey's fix for mitochondrial mutation, for instance, is to smuggle backup copies of DNA from the mitochondria into the vault of the nucleus, which evolution annoyingly failed to do-probably because the proteins needed in the mitochondria would ball up during their journey through the watery cell body. His fix for that, moving the DNA one way and the proteins that it produces another, amounts to a kind of subcellular hokey pokey. A number of scientists praise de Grey for anatomizing the primary threats, yet they see troubleshooting all seven pathways through such schemes - and you have to troubleshoot them all for his plan to work - as a foredoomed labor. Biogerontologist Matt Kaeberlein said, "It's like saying, 'All we have to do to travel to another solar system is these seven things: first, accelerate your rocket to three-quarters of the speed of light... ' "

Ned David is a biochemist and a co-founder of a Silicon Valley startup called UNITY Biotechnology. UNITY targets senescent cells - cells that, as they age, start producing a colorless, odorless, noxious goo called SASP, which UNITY's researchers call "the zombie toxin," because it makes other cells senescent and spreads chronic inflammation throughout the body. In mice, UNITY's treatments delay cancer, prevent cardiac hypertrophy, and increase median life span by thirty-five per cent. "We think our drugs vaporize a third of human diseases in the developed world." Pharma and biotech companies make money only if they treat a disease, and, because aging affects everything, the FDA doesn't recognize it as an "indication" susceptible to treatment (or to insurance-company reimbursement). So UNITY is taking aim at glaucoma, macular degeneration, and arthritis.

It has to be said that allotopic expression of mitochondrial genes in the cell nucleus is a poor example to pick for something that is alleged to be a doomed labor. The work has been accomplished for three of the thirteen genes needed; this is a capability that exists, and is underway towards completion. The allotopic expression of ND4 is the basis for a therapy that is currently going through clinical trials in Europe. Yes, it takes work, but so does everything else. This is one of the things that frustrates me immensely about many of the critics of SENS - they willfully ignore the progress that has been made, pretending it doesn't exist.

And that isn't even to start in on what is said - and, more importantly, not said - about senescent cell clearance, something that de Grey and other SENS advocates have been promoting as a path to treat aging for the past fifteen years, on the basis of strong evidence. It is right there in the SENS outline; hard to miss. Targeted removal of senescent cells has finally taken off these past few years, the evidence for a significant impact on aging has grown to be nigh irrefutable, and near everyone in the research community is enthused. Yet SENS and many researchers' past rejection of senescent cell clearance as a part of SENS is swept under the rug, never to be mentioned. It is unconscionable behavior, and it happens here: despite covering UNITY Biotechnology, the senolytics company, no mention of senescent cells is made in connection with the SENS vision. It takes some brass to claim SENS to be a doomed effort and then roll right into a discussion with one of the UNITY co-founders on the topic of removing senescent cells to treat aging.

Link: http://www.newyorker.com/magazine/2017/04/03/silicon-valleys-quest-to-live-forever

Fight Aging! Invests in CellAge, Developing New Cellular Senescence Assays

CellAge is one of the new initiatives arisen in recent years from our community of longevity science advocates and researchers. The principals are focused on the biology of senescent cells, and are attempting to apply the new technology of synthetic gene promoters in order to produce a better class of assay for cellular senescence in living tissue. This will test for amounts and types of senescent cell, improving upon the current standard approaches used in research, protocols that have been around for ten to twenty years and are by now showing their age. They are good enough for the sort of lab work that has taken place over that time, but certainly not good enough for the near future in which targeted removal of senescent cells becomes a widespread clinical therapy. This approach to the treatment of aging as a medical condition has great promise, but those therapies will certainly have to be accompanied by low-cost, reliable assays to assess exactly how well they work. I'm very much in favor of efforts to produce the next generation of cellular senescence assays, as this provides an important form of support for the companies that are presently working on senescent cell clearance approaches.

As I'm sure you'll recall, CellAge started out by crowdfunding their initial work via Lifespan.io. The aim of this first project, now underway, is to produce an improved assay for senescent cells that the company will release for free to the academic community. It was a challenging fundraiser, largely because of the timing, as our community had given a great deal to various other fundraisers over the course of 2016. It was stuck for quite some time half-way to the target. While that was the case, a few of us started to cast around for alternative sources of funding from the for-profit investment community, something always intended by the CellAge founders, just not quite so soon. Putting together a funding round for a very early stage company always takes longer than you think it will to reach a useful conclusion; it is something like herding cats, and a great deal more legally complicated than it needs to be, especially for the UK where CellAge is based. While this process was underway, the CellAge fundraiser came to a much more successful conclusion than hoped, thanks to the hard work of the Life Extension Advocacy Foundation volunteers and the generosity of a number of significant donors. Very gratifying!

Now, on top of that crowdfunding success, I'm pleased to note that the initial CellAge investment round has finally completed assembly, with one of the professional VCs in our community taking the lead and accomplishing the heavy lifting in organizational matters. Fight Aging! and a small group of other angel investors joined in, collectively stretching our available funds in order to give the CellAge founders the fuel they need to reach the next stage following their initial proof of concept work. The hope is that CellAge should have interesting things to demonstrate by the end of the year, and into 2018.

On this topic, it is worth noting that our community has few scientific entrepreneurs. Yet such entrepreneurs play a vital role in the path that leads from concept through research to realized therapy. I think it important that we do our part to assist those researchers who are willing and able to make the leap to successfully starting a company to carry forward their work. In the years ahead they will be the ones picking up new projects and helping to push new rejuvenation therapies from the laboratory to the clinic. They will be the ones employing the next generation of researchers and biotechnologists, inspiring them to make the same leap into medical development. For the SENS vision of human rejuvenation to succeed in the decades ahead, the SENS Research Foundation and its allies must have a diverse community of entrepreneurs to call upon, an important addition to the existing network of researchers and research groups. The CellAge team are first-time founders, but learn quickly, have a great background in the underlying science, and clearly have the right stuff to make a go of it. I'm happy to have been able to do a little to help them build their network and company.

Can a Useful Biomarker of Aging be Built from Very Simple Measures?

There is considerable interest in the research community in the construction of a low-cost, reliable biomarker of biological age. The intent is to use such a test immediately before and after the application of a potential rejuvenation therapy to establish how well it worked. It must therefore accurately assess overall health, mortality risk, and remaining life expectancy. Currently DNA methylation assays are a leading approach to the creation of a robust biomarker of aging, as some portions of the changing pattern of DNA methylation are a fairly good reflection of cellular reactions to the damage and decline of aging. Is it possible to produce something far less complicated, however, a biomarker that uses only existing measures of health, but that is nonetheless good enough to evaluate near future rejuvenation therapies? This is an open question, one that can be argued either way.

Mammalian aging is characterized by a gradual decline of numerous health parameters with multiple biochemical, physiological and behavioral manifestations. Several animal models have been successfully used over the last several decades to address mechanistic aspects of aging and development of age-related diseases. In most of these studies the major metric parameter for assessing pro-/anti-aging effect of genetic, nutritional or pharmacological manipulation has been the animals' lifespan. While being informative, longevity by itself however, cannot provide an assessment of the animal's health status, which, like in humans, can significantly decline at older ages and therefore reduce the quality of life. This concern is particularly relevant to research focused on developing the "healthspan"-extending pharmaceuticals, efficacy of which may not be necessarily translated in increased longevity but rather in prolongation of healthy life and require quantitative objective assessment.

Clinical studies in humans measure age-related declines in performance by quantifying the frailty index (FI), which reflects accumulation of health deficits during chronological aging. Since numerous studies have shown that many age-associated changes that occur in humans are also present in aged mice, FI was recently introduced as a measure of mouse aging to pre-clinical models. However, standardized and comprehensive approaches for FI measurements, which will address changes in a broad spectrum of physiological functions, are still missing. Here we describe the development of an alternative scoring system, based on a selected set of non-invasive quantitative and physiological parameters, which could be repetitively used in the same animal over the course of its entire lifespan. We refer to this set of parameters as physiological frailty index (PFI). After measuring 29 diverse parameters including physical (body weight and grip strength), blood cell composition, metabolic, and immune properties, we selected those that show statistically significant change with age. These parameters were used to create PFI of individual mice of different chronological age. The observed gradual increase in mean PFI values with age suggests that our approach can reliably detect the scale of age-dependent health deterioration in a quantitative manner.

We also validated our approach of PFI by testing detrimental (feeding high fat diet, HFD) and beneficial (treatment with mTOR inhibitor rapamycin) factors on animals' longevity. We demonstrated acceleration of growth of PFI in animals placed on a high fat diet, reflecting aging acceleration by obesity. Additionally, we showed that PFI could reveal the anti-aging effect of mTOR inhibitor rapatar (a bioavailable formulation of rapamycin) prior to registration of its effects on longevity. PFI also revealed substantial sex-related differences in normal chronological aging and in the efficacy of detrimental (high fat diet) or beneficial (rapatar) aging modulatory factors.

Link: http://dx.doi.org/10.18632/aging.101206

Calico Partners to Obtain Protein Degradation Technology

For those who like reading the Calico tea leaves, here are a few details on one of their recent partnerships. Calico, the California Life Company, is the aging research venture funded by Google. It launched a few years back, but so far those involved appear to be doing nothing particularly radical, insofar as we know anything about what is going on there. Calico is certainly not supporting the SENS view of damage repair as the best way to treat aging, and may well be turn out to be simply a larger and more secretive version of the Ellison Medical Foundation in the end: an expansion of the largely investigative work already taking place at the NIA, undertaking no projects with the potential to make a large difference to the course of aging in humans. More research is always better than less research, of course, but nonetheless this has grown to have the look of another missed opportunity to add to the recent history of aging research.

Here, Calico is partnering to obtain access to a technology that could be turned to ways to adjust the level of any one or any few of the proteins present in a cell. The approach works by harnessing one of the cell's established recycling mechanisms. This might be intended as an alternative to methods such as RNA interference for use in adjusting cellular operation. The goal is to tinker with the switches and dials of metabolism, all of which are influenced or determined by levels of specific proteins, in order to test approaches that might slightly slow aging by reducing the pace at which damage accumulates. More positively, it might be turned to degrading forms of metabolic waste that cause aging, though beyond amyloid and Alzheimer's disease, there is little sign that Calico researchers are interested in the list of waste compounds outlined in the SENS rejuvenation research proposals, such as cross-links, lipofusin, and so forth.

C4 Therapeutics (C4T) and Calico today announced a five-year collaboration to discover, develop, and commercialize therapies for treating diseases of aging, including cancer. Under the terms of the agreement, the parties will leverage C4T's expertise and capabilities in targeted protein degradation to jointly discover and advance small molecule protein degraders as therapeutic agents to remove certain disease-causing proteins. The partnership will pursue preclinical research and Calico will be responsible for subsequent clinical development and commercialization of resulting products that may emerge from the collaboration.

"We know from decades of translational research that it can be incredibly challenging to find effective pharmacologic inhibitors of many of the biologically well-validated targets, particularly in cancer. Through the alternative strategy of specifically targeting such proteins for degradation, we believe we have the opportunity to identify promising new therapeutics in cancer and in other diseases as well. We're looking forward to collaborating with C4T's scientists and applying their protein degradation technology to the discovery and development of effective new treatments."

C4 Therapeutics is a private biotechnology company developing a new class of drugs based on Targeted Protein Degradation (TPD) to address a broad range of life-threatening and life-impairing diseases. C4T's platform uses small molecule drugs to direct the machinery of the ubiquitin-proteasome system to selectively degrade disease-relevant proteins for therapeutic benefit. This distinctive mechanism provides new opportunities to target traditionally difficult-to-treat diseases and diseases plagued by drug resistance.

Link: http://www.calicolabs.com/news/2017/03/23/

What Next for UNITY Biotechnology?

What follows here is an inside baseball discussion relating to the companies working on senolytic therapies, biotechnologies capable of selectively destroying senescent cells. The presence of these cells is one of the causes of aging and age-related disease, and their removal is the first of a number of rejuvenation therapies based on the SENS vision that will emerge over the next few decades. Human trials of the first senolytics will be starting this year and next, and by the mid-2020s most people in the wealthier parts of the world will have the opportunity to remove this part of the burden of aging. This is a wondrous development: based on research to date, removing senescent cells from old individuals is a robust and reliable way to turn back the clock on many measures of aging and markers of age-related disease.

I should preface the rest of this post by noting that competition in the marketplace is a great thing, but only because some investors suffer meaningful losses. The threat of loss is necessary to the alchemy by which self-interest is turned into altruism. Only competition with real penalties for failure can drive the faster progress that benefits everyone. Yet regardless of who wins or loses in terms of the value of their shares, we all win when reasonably priced senolytic therapies become widely accessible. In that sense, investing in credible ventures aiming at the production of rejuvenation therapies is a great opportunity: even failure contributes to progress, and the outcome in the end is that we are all better off. Someone achieves the goal, someone deploys the treatment.

UNITY Biotechnology is presently at the head of the current crop of companies focused on treating aging and age-related disease through the clearance of senescent cells. They hold the leading position by virtue of the involvement of the principal research groups in the field, having big names from the pharmaceutical and biotech field running the show, and having recently raised more than $100 million to push the first of these therapies through the US regulatory progress and into the clinic. Yet I can't say as I think that their position is as enviable and commanding as it might first appear to be. From a competitive point of view, they actually have very little going for them at the moment aside from that war chest and the credibility it took to raise it.

Having made that statement, I should defend my position. The chief problem I see for UNITY is one of technology. They are taking a small molecule drug approach within the current regulatory system, and the currently available stable of senolytic drug candidates with which they entered the picture are chemotherapeutics with significant side-effects. Other drug candidates are emerging quite rapidly in the research community, some of which may have far fewer side-effects, but switching would mean starting fresh, or licensing fresh from current owners. It might also mean moving from a well-characterized drug with excellent pharmacology data, such as navitoclax, to a drug that still needs that data established. The situation is actually worse than this, however. Competitors with far better senescent cell clearance technologies, approaches with essentially zero side-effects, are emerging at the rate of one every year or so. Oisin Biotechnologies was the first, using a programmable gene therapy approach, and just this week another group announced their intent to form a company to develop their FOXO4-p53 interference method.

UNITY didn't emerge from thin air, and their precursor company does have a variety of patents and experience in trying to get immunotherapies and engineered viruses to work as senolytic treatments. They had plenty of time to try to get that to work and did not achieve those goals. With what is now a great deal of funding in comparison to the past, they could go back and try to make one of those approaches work. There is a great deal of uncertainty in that sort of endeavor, however. They should and no doubt will turn some of their funding to longer-term technology development with perhaps a five-year horizon, but when you take as much venture funding as this company has, the clock ticks very aggressively. They have to build a multi-billion-dollar valuation company pretty quickly, within the next couple of years. That has to be done on the basis of human trials starting right about now, since those clinical trials will take a year or so to run from idea to publication of results.

Another threat is that of medical tourism. Not everyone in this global industry is going to care about the opinions of the FDA. Given that existing senolytic drugs, and many of the new ones, can be purchased from established suppliers, there really is little to stop a large industry of medical tourism springing up for the very same drugs that UNITY is trying to put through the system. Or at the very least for drugs that are similar enough in effectiveness and side-effects. That will hamper UNITY's ability to charge regulatory capture prices; it is harder to do that when people can just go to Mexico at a tenth or less of the US price. That in turn will harm their valuation and ability to raise further funding needed to run treatments through the FDA gauntlet.

A final consideration is that everything UNITY spends money on today helps their competitors just as much as it helps them. One might argue that the big UNITY war chest is really largely a charity fund for industry development. Being a competitor to UNITY is one of the greatest places to be in modern for-profit biotechnology. They are doing all the work to prove out the industry, raise its profile, and demonstrate with ever-better clarity that targeted destruction of senescent cells successfully treats aging. They are doing more than their part to set a high initial valuation for any other new company with a credible technology for targeting senescent cells. This is all wonderful from the point of view of anyone waiting for the end result to emerge in clinics, but pretty terrible for UNITY from a competitive point of view. They'll be hip-deep in highly effective competing companies come this time in 2019.

As I see, it the UNITY management has a few options when it comes to strategy. Firstly they can forge ahead in the hope that regulatory barriers are good enough to allow a large valuation based on approval for a chemotherapeutic that is (a) inferior to a range of other treatments only a little behind in time to market, and (b) also available on the open market for medical tourism. Secondly they can couple that approach with significant investment in development of new drugs that can be patented, variants of those already discovered. These two are more or less the standard playbook for a new pharmaceutical entity, so they may well do this and only this. If they do, I think that their competitors, already equipped with far superior products, will eat their lunch over the next few years, however. The third option is to continue to prove out the market, make life easy for competitors, run the first trials, pull in another even larger round of funding at some ridiculous valuation, and then use those funds to buy the best of the crop of competitors, solving the technology problem.

This last option seems plausible, and is not uncommmon. I think it quite likely that UNITY will kick off their chemotherapeutic trials, publish the promising initial results while downplaying the side-effects, raise series C in 2018, and then buy whichever of the young companies in the space with a better senolytic technology wants to sell for a quick turnaround. Despite the enormous size of the target market here, ultimately every adult human much over the age of 30 buying a treatment every few years, not every entrepreneur wants to spend a decade fighting the FDA to make progress towards a narrow, limit use of their therapy. A quick win and sudden wealth is a strong temptation; anyone starting up a senescence-focused biotech company these days will have an acquisition by UNITY somewhere in mind as an option - as will the investors who back those companies.

Considering Uncoupling in Calorie Restriction Mimetics

This open access paper on mitochondrial function considers the mechanism of uncoupling in calorie restriction and in drugs that seek to emulate some of the benefits produced by calorie restriction, known as calorie restriction mimetics. Mitochondria generate energy stores for use in cells, but with greater uncoupling that effort creates heat instead. This is a part of the normal process of body temperature regulation in mammals. However, uncoupling also changes the output of reactive oxygen species (ROS) from the mitochondria, a feature observed in the methods shown to modestly slow aging in short-lived species. Mitochondrially generated ROS are both a signal that spurs greater cellular housekeeping and a source of damage, so either somewhat more or somewhat less than the usual output might be beneficial.

There are drugs known to reliably produce greater mitochondrial uncoupling, but there has little development of their use as therapeutics for aging, even now that the research community has more enthusiasm for the goal of slowing aging via pharmaceuticals. This is possibly because unbounded increases in uncoupling via drug administration are fairly dangerous: too much is potentially lethal due to raised body temperature and harmful effects on mitochondrial biochemistry. Since this lack of safety at the higher end is an inherent feature of uncoupling in mammals, it may well be the case that direct intervention in the uncoupling process will remain less desirable in comparison to the range of other potential approaches to modestly slow aging in humans. That said, the researchers here point out a family of self-limiting uncouplers that may not exhibit this problem; we shall see how it goes in the years ahead.

Caloric restriction (CR) is the best-studied and most reliable way to increase lifespan. CR affects most of experimental model organisms, from unicellular ones to mammals. Signaling cascades responsible for the effects of CR were studied in detail at the cellular level as well as at the levels of tissues and the whole organisms. Increasing levels of AMP and NAD+, which activates deacetylases, were shown to be the key factors initiating these cascades at the cellular level. One could expect that under the conditions of CR the cells attempt to save energy. Many cellular changes indeed make bioenergetics more economical: CR decreases the rate of protein biosynthesis and activates autophagy. It would be natural to presume that CR also raises the efficiency of mitochondrial energy production, i.e. that it increases the coupling of respiration and oxidative phosphorylation. However the opposite appears to take place.

It has been shown that mice under CR conditions accumulate UCP proteins (uncoupling proteins) in their muscle mitochondria. UCP proteins catalyze an electrogenic process of transporting the dissociated forms of free fatty acids from the inner to the outer layers of mitochondrial inner membrane. In the outer layer the free fatty acids are protonated, and then in the neutral form return to the inner layer. As this decreases the level of the transmembrane potential, the proteins of the UCP family act as natural uncouplers of respiration and oxidative phosphorylation. Indeed, during starvation there is simultaneous accumulation of UCP2 and UCP3, and a decrease a decrease in the efficiency of oxidative phosphorylation. What is the physiological role of uncoupling activation upon CR? On one hand, CR induces mitochondrial biogenesis and respiration. On the other hand, it has been shown that mitochondrial hyperpolarization can induce a strong increase in ROS (reactive oxygen species) generation. Probably, the increased expression of UCP is an "insurance" against the oxidative stress caused by mitochondrial hyperpolarization.

There is probably another advantage of using uncouplers as CR mimetics. As aforementioned, increase in NAD+ levels is one of the best-studied ways of geroprotection. There are many works showing that increasing NAD+ concentration via activation of its biosynthesis leads to lifespan increase in experimental animals. Importantly, in terms of lifespan increase in the sum of NAD+ and NADH concentrations is less relevant than the concentration of the oxidized form. At the same time, reduction of NAD+ to NADH takes place during cellular catabolic reactions (glycolysis and TCA cycle). Therefore, interfering with cell metabolism could be an efficient way of increasing NAD+ concentration. The addition of the uncoupler FCCP at low concentration has been shown to increase ATP level in neurons due to a compensatory response to a temporal depolarization. Earlier, it has been suggested that a slight decrease in the transmembrane potential can prevent the reaction of one-electron reduction of oxygen, which leads to ROS formation. At the same time, such a decrease may not affect the rate of ATP synthesis; thus, such uncoupling was called "mild". In other words, mild uncoupling is aimed at stimulating NAD+-dependent processes rather than at stimulation of AMPK.

What level of uncoupling is most suitable for the purposes of geroprotection? As mentioned, a small decrease in proton resistance of the strongly energized mitochondrial membranes can induce a significant decrease in ROS production and an increase in NAD+/NADH ratio without affecting ATP concentration. According to our line of reasoning, such level of uncoupling combined with AMPK activation is sufficient for efficient interference with the aging process. Theoretically, one could consider a higher level of uncoupling leading to a strong depolarization of the membranes and, as a consequence, a significant increase in ADP/ATP ratio. Apparently, such treatment could lead to a lethal deenergization of cells. Therefore, a relatively weak level of uncoupling seems to be preferential.

Which uncouplers should be used? Probably, the anionic compound dinitrophenol is the best-studied uncoupler in terms of its effects on mammalian physiology. In particular, it has been used on humans as a weight loss treatment. However, it was reported that its use was accompanied by a set of negative side effects. Recently, we reported uncoupling activity of a unique type of chemical compounds - lipophilic penetrating cations. Most of the studies on such compounds were performed on dodecyltriphenylphosphonium (C12TPP). A potential advantage of using such compounds is that their mitochondrial accumulation is proportional to the level of the transmembrane potential. For this reason, penetrating cations affect highly polarized mitochondria to greater extent than mitochondria with relatively low potential levels. In other words, they cause self-limiting (mild) uncoupling.

Link: http://protein.bio.msu.ru/biokhimiya/contents/v81/full/81121713.html

NAD Precursor NMN Improves DNA Repair in Mice

Sirtuin research, much hyped and in the end producing nothing other than more knowledge of metabolism, has somewhat transitioned into a focus on nicotinamide adenine dinucleotide (NAD) these days. NAD is central in cellular energy production and mitochondrial activity, and appears involved in many of the same processes that sirtuins influence. It is still the case that compelling demonstrations of slowed aging or enhanced longevity in laboratory animals have yet to emerge from this line of research, such as via the use of the NAD precursor nicotinamide mononucleotide (NMN) as a dietary supplement. The research is academically interesting, as here where it is shown to affect DNA repair mechanisms, but from a practical point of view for the treatment of aging this still appears to be another marginal approach, lacking the ability to produce reliable and significant effects on aging and longevity.

DNA repair is essential for cell vitality, cell survival and cancer prevention, yet cells' ability to patch up damaged DNA declines with age for reasons not fully understood. New findings offer an insight into how and why the body's ability to fix DNA dwindles over time and point to a previously unknown role for the signaling molecule NAD as a key regulator of protein-to-protein interactions in DNA repair. If affirmed in further animal studies and in humans, the findings can help pave the way to therapies that prevent DNA damage associated with aging and with cancer treatments that involve radiation exposure and some types of chemotherapy, which along with killing tumors can cause considerable DNA damage in healthy cells. Human trials with NMN are expected to begin within six months, the researchers said.

The investigators started by looking at a cast of proteins and molecules suspected to play a part in the cellular aging process. Some of them were well-known characters, others more enigmatic figures. The researchers already knew that NAD, which declines steadily with age, boosts the activity of the SIRT1 protein, which delays aging and extends life in yeast, flies and mice. Both SIRT1 and PARP1, a protein known to control DNA repair, consume NAD in their work. Another protein DBC1, one of the most abundant proteins in humans and found across life forms from bacteria to plants and animals, was a far murkier presence. Because DBC1 was previously shown to inhibit vitality-boosting SIRT1, the researchers suspected DBC1 may also somehow interact with PARP1, given the similar roles PARP1 and SIRT1 play.

To get a better sense of the chemical relationship among the three proteins, the scientists measured the molecular markers of protein-to-protein interaction inside human kidney cells. DBC1 and PARP1 bound powerfully to each other. However, when NAD levels increased, that bond was disrupted. The more NAD present inside cells, the fewer molecular bonds PARP1 and DBC1 could form. When researchers inhibited NAD, the number of PARP1-DBC1 bonds went up. In other words, when NAD is plentiful, it prevents DBC1 from binding to PARP1 and meddling with its ability to mend damaged DNA. What this suggests is that as NAD declines with age, fewer and fewer NAD molecules are around to stop the harmful interaction between DBC1 and PARP1. The result: DNA breaks go unrepaired and, as these breaks accumulate over time, precipitate cell damage, cell mutations, cell death and loss of organ function.

Next, to understand how exactly NAD prevents DBC1 from binding to PARP1, the team homed in on a region of DBC1 known as a Nudix homology domain (NHD), a pocket-like structure found in some 80,000 proteins across life forms and species whose function has eluded scientists. The team's experiments showed that NHD is an NAD binding site and that in DBC1, NAD blocks this specific region to prevent DBC1 from locking in with PARP1 and interfering with DNA repair. To determine how the proteins interacted beyond the lab dish and in living organisms, the researchers treated young and old mice with the NAD precursor NMN, which makes up half of an NAD molecule. NAD is too large to cross the cell membrane, but NMN can easily slip across it. Once inside the cell, NMN binds to another NMN molecule to form NAD. As expected, old mice had lower levels of NAD in their livers, lower levels of PARP1 and a greater number of PARP1 with DBC1 stuck to their backs.

However, after receiving NMN with their drinking water for a week, old mice showed marked differences both in NAD levels and PARP1 activity. NAD levels in the livers of old mice shot up to levels similar to those seen in younger mice. The cells of mice treated with NMN also showed increased PARP1 activity and fewer PARP1 and DBC1 molecules binding together. The animals also showed a decline in molecular markers that signal DNA damage. In a final step, scientists exposed mice to DNA-damaging radiation. Cells of animals pre-treated with NMN showed lower levels of DNA damage. Such mice also didn't exhibit the typical radiation-induced aberrations in blood counts, such as altered white cell counts and changes in lymphocyte and hemoglobin levels. The protective effect was seen even in mice treated with NMN after radiation exposure.

Link: http://www.newswise.com/articles/harvard-medical-school-scientists-pinpoint-critical-step-in-dna-repair-cellular-aging

Selective Destruction of Senescent Cells by Interfering in FOXO4-P53 Crosstalk

Today, another research group announced their entry to the field of senescent cell clearance as a means to treat aging, along with the intent to commercialize their novel method of achieving selective destruction of senescent cells in aged individuals. Senescent cells accumulate with age as a result of the normal operation of living tissues: cells become senescent when damaged or when they reach the Hayflick limit on replication. Near all are destroyed, either through the programmed cell death mechanism of apoptosis, or by immune cells attracted by the signal molecules generated by senescent cells. Unfortunately, some linger, resistant. The number of these cells grows over the years, and the signals they generate start to create harmful outcomes in nearby cells and tissue structures, and in addition spur rising levels of chronic inflammation. The increasing presence of senescent cells is one of the root causes of degenerative aging and directly contributes to many specific age-related diseases.

The best and most direct approach to the phenomenon of cellular senescence is to periodically destroy these cells, reducing their numbers to the greatest extent possible. These numbers are never enormous, perhaps a few percent of most tissues in late old age, depending on the details. Removal can proceed as slowly as needed to be safe in older individuals if there are risks of lysis side-effects due to the amount of cell debris generated by senescent cell destruction. While senescence has short-term roles to play in tumor suppression, by shutting down the ability to replicate in potentially cancerous cells, and in wound healing, these cells have no clear and evident long-term use in the body. So a treatment that gets rid of near all of these cells, undergone once every few years, would in fact be a narrow means of rejuvenation. It would make aged tissues less aged. This has been demonstrated in studies of senescent cell removal showing life extension in mice, as well as those that have demonstrated specific improvements and reversals in the pathology of various age-related diseases and aged tissues.

The methodology developed by the researchers noted here is, at the very high level, analogous to that involved in some of the senolytic drug candidates evaluated to date - though it has the merit of having far fewer side-effects per this report. It involves sabotaging one of the mechanisms that lingering senescent cells use in order to resist the fall into apoptosis, but which in normal cells has no important role to play. Thus drug molecules can be delivered everywhere, and will only produce significant effects in cells that are senescent. In the case of drugs like navitoclax, that mechanism involves inhibiting bcl-2 family proteins. The mechanism here is quite different, involving FOXO4's influence on p53, but I wouldn't be surprised to see it turn out to be a part of the same system of inhibition of apoptosis. Almost all cellular mechanisms can be influenced in many ways, by tinkering with the activities and actions of many directly and indirectly involved proteins, and it is not unusual for research groups initially working on a diverse set of proteins to find that they end up in the same place at the end of the day.

Peptide targeting senescent cells restores stamina, fur, and kidney function in old mice

Regular infusions of a peptide that can selectively seek out and destroy broken-down cells that hamper proper tissue renewal, called senescent cells, showed evidence of improving healthspan in naturally-aged mice and mice genetically engineered to rapidly age. The peptide took over four years of trial and error to develop and builds on nearly a decade of research investigating vulnerabilities in senescent cells as a therapeutic option to combat some aspects of aging. It works by blocking the ability of a protein implicated in senescence, FOXO4, to tell another protein, p53, not to cause the cell to self-destruct. By interfering with the FOXO4-p53 crosstalk, the peptide causes senescent cells to go through apoptosis, or cell suicide. "Only in senescent cells does this peptide cause cell death. We treated mice for over 10 months, giving them infusions of the peptide three times a week, and we didn't see any obvious side effects. FOXO4 is barely expressed in non-senescent cells, so that makes the peptide interesting as the FOXO4-p53 interaction is especially relevant to senescent cells, but not normal cells."

Results appeared at different times over the course of treatment. Fast-aging mice with patches of missing fur began to recover their coats after 10 days. After about three weeks, fitness benefits began to show, with older mice running double the distance of their counterparts who did not receive the peptide. A month after treatment, aged mice showed an increase in markers indicating healthy kidney function. "The common thread I see for the future of anti-aging research is that there are three fronts in which we can improve: The prevention of cellular damage and senescence, safe therapeutic removal of senescent cells, to stimulate stem cells - no matter the strategy - to improve tissue regeneration once senescence is removed."

Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis in Response to Chemotoxicity and Aging

To identify potential pivots in senescent cell viability, we initiated this study by investigating whether apoptosis-related pathways are altered in senescent cells. We performed unbiased RNA sequencing on samples of genomically stable primary human IMR90 fibroblasts and IMR90 induced to senesce by ionizing radiation (IR). As senescent cells are reportedly apoptosis-resistant, we expected pro-apoptotic genes to be repressed. Surprisingly, however, senescent IMR90 showed an upregulation of prominent pro-apoptotic "initiators" PUMA and BIM while the anti-apoptotic "guardian" BCL-2 was reduced. This suggested senescent IMR90 are primed to undergo apoptosis but that the execution of the death program is restrained. We reasoned such a brake could potentially be a transcriptional regulator and focused on transcription factors that have previously been linked to apoptosis, including STAT1, 2, and 4; RELB; NFκB; TP53; and FOXO4.

Interference with JAK-STAT signaling is known not to affect the viability of senescent cells, and we have previously observed similar effects for NFκB and p53 inhibition. Our interest was therefore directed to a factor that has not yet been studied as such, FOXO4. FOXO4 belongs to a larger mammalian family, with FOXO1 and 3 being its major siblings. FOXOs are well studied in aging and tissue homeostasis as targets of insulin/IGF signaling and as regulators of reactive oxygen species. Whereas senescence-inducing IR showed only mild effects on the expression of FOXO1 and 3, both FOXO4 mRNA and protein expression progressively increased. We therefore wondered whether FOXO4 could function to balance senescence and apoptosis. We stably inhibited FOXO4 expression using lentiviral shRNA. FOXO4 inhibition prior to senescence-induction resulted in a release of mitochondrial cytochrome C and BAX/BAK-dependent caspase-3 cleavage. In addition, FOXO4 inhibition in cells that were already senescent, but not their control counterparts, reduced viability and cell density. Together, these show that after acute damage FOXO4 favors senescence over apoptosis and maintains viability of senescent cells by repressing their apoptosis response.

Research on peptide chemistry has shown that protein domains containing natural L-peptides can sometimes be mimicked by using D-amino acids in a retro-reversed sequence. Modification of peptides to such a D-retro inverso (DRI)-isoform can render peptides new chemical properties, which may improve their potency. As a cell penetrating peptide the D-retro inverso (DRI)-isoform of FOXO4, FOXO4-DRI, differs from other senolytic compounds by being designed around a specific amino acid sequence in a molecular target only mildly expressed in most normal tissues. Though a more thorough analysis is required, at least as far as tested here FOXO4-DRI appears to be well tolerated, which is an absolutely critical milestone to pass when aiming to treat relatively healthy aged individuals.

Reviewing What is Known of the Aging of Stem Cells

One of the important contributions to the aging process is a progressive reduction in stem cell activity. The majority of tissues in the body are in a constant process of turnover. The somatic cells making up the bulk of all tissues reach the Hayflick limit on replication and self-destruct, and are replaced by new cells generated by tissue-specific stem cell populations. With age, these stem cells spend ever more time quiescent, and thus the supply of new somatic cells declines, causing tissues and organs to deteriorate and ultimately fail. This loss of stem cell support is thought to have evolved as part of a balance between risk of death by cancer versus risk of death through failing tissues. As cells become more damaged with age, the risk of cancer with cell activity increases. Lower cells of stem cell activity dampen that risk somewhat, at the cost of a slower decline into frailty and disease. Still, restoration of youthful stem cell activity is one necessary component of any future toolkit of rejuvenation therapies. To the degree that this raises cancer risk, that is an additional challenge to overcome along the way, not a reason to stand back and do nothing.

Aging is an unavoidable physiological consequence of the living animals. Mammalian aging is mediated by the complex cellular and organismal processes, driven by diverse acquired and genetic factors. Aging is among the greatest known risk factors for most human diseases, and of roughly 150,000 people who die each day across the globe, about two thirds die from age-related causes. In the modern era, one of the emerging fields in medicine is stem cell research, as stem cells have the remarkable potential for use to treat a wide range of diseases. Stem cells are undifferentiated pluripotent cells that can give rise to all tissue types and serve as a sort of internal repair system. Until the recent advance in development of induced pluripotent stem cells (iPSCs), scientists primarily worked with two kinds of pluripotent stem cells from animals and humans: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and non-embryonic "somatic" or "adult" stem cells, which are found in various tissues.

Although stem cell science promises to offer revolutionary new ways of treating diseases, it is identified that aging affects the ability of stem (and progenitor) cells to function properly, which ultimately can lead to cell death (apoptosis), senescence (loss of a cell's power of division and growth), or loss of regenerative potential. Aging may also shift gene functions, as reported for some genes, such as p53 and mammalian target of rapamycin (mTOR), which are beneficial in early life, but becomes detrimental later in life. In this regard, a novel theory, namely the "stem cell theory of aging", has been formulated, and it assumes that inability of various types of pluripotent stem cells to continue to replenish the tissues of an organism with sufficient numbers of appropriate functional differentiated cell types capable of maintaining that tissue's (or organ's) original function is in large part responsible for the aging process.

In addition, aging also compromises the therapeutic potentials of stem cells, including cells isolated from aged individuals or cells that had been cultured in vitro. Nevertheless, in either case, understanding the molecular mechanism involved in aging and deterioration of stem cell function is crucial in developing effective new therapies for aging- as well as stem cell malfunction-related diseases. In fact, given the importance of the aging-associated diseases, scientists have developed a keen interest in understanding the aging process as well as attempting to define the role of dysfunctional stem cells in the aging process.

From the various advances in stem cell research, it is clear that we grow old partly because our stem cells grow old with us. The functions of aged stem cells become impaired as the result of cell-intrinsic pathways and surrounding environmental changes. With the sharp rise in the aging-associated diseases, the need for effective regenerative medicine strategies for the aged is more important than ever. Fortunately, rapid advances in stem cell and regenerative medicine technologies continue to provide us with a better understanding of the diseases that allows us to develop more effective therapies and diagnostic technologies to better treat aged patients.

Link: https://dx.doi.org/10.5493/WJEM.v7.i1.1

Strategies for Cardiovascular Regeneration via Cell Therapies

Researchers here review one slice of the cell therapy field, examining the use of mesenchymal stem cells to provoke greater regeneration of heart tissue than normally takes place. While stem cell therapies are generally at least marginally beneficial, with reduction in inflammation the most reliable outcome to date, the research community has so far struggled to consistently produce larger benefits when it comes to heart damage in older people.

The treatment approach for the majority of cardiovascular disease is to administer drugs, and some cases may require surgery such as coronary angioplasty with stent insertion. The incidence of cardiovascular disease has continued to increase, and aside from transplantation, other therapies, despite recent advances in heart treatments, cannot fundamentally remedy the major etiology of cardiovascular disease; thus, there is a limit to how much treatment outcomes can be improved with the current approaches. Although various studies have been conducted ​​to overcome the limitations of cardiovascular therapies, stem cell therapy using several types of stem cells such as hematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs), cardiac stem cells (CSCs), and endothelial progenitor cells (EPCs) provides an alternative approach, and ​​remarkable advances have been made in clinical and basic research.

Among adult stem cells, MSCs are frequently used to treat the most common cardiovascular diseases. MSCs can be found in the bone marrow (BM), adipose tissue, umbilical cord blood (UCB), and many other tissues. They have self-renewing properties and are multipotent progenitor cells that can differentiate into various lineages such as osteocytes, chondrocytes, adipocytes, and myocytes. MSCs also have immunomodulatory properties, and in addition MSCs are unlikely to lead to immune rejection. The therapeutic benefit of this approach is based on the potency of secretion of beneficial cytokines and growth factors for tissue repair/regeneration, as well as the immunomodulation effect and/or their differentiation for regenerating damaged organs.

MSCs can be applied for cardiovascular regeneration and provide therapeutic benefit for cardiovascular disease. However, MSCs have several disadvantages regarding their therapeutic application, including their very low survival rate in vivo and integration rate into the host cells after transplantation. Another limitation is the low accuracy in delivering the stem cells to the damaged site. Various attempts have been made to improve the poor survival and longevity of engrafted MSCs. The first step in developing therapeutic strategies is the identification of more effective reagents for promoting the ability of stem cells via understanding stem cell niche modulators. An emerging promising therapeutic strategy is the preconditioning of MSCs before transplantation using cytokines and natural compounds that induce intracellular signaling or niche stimulation through paracrine mechanisms. Another is a tissue engineering-based therapeutic strategy involving a cell scaffold, a cell-protein-scaffold architecture made of biomaterials such as extracellular matrix or hydrogel, and cell patch- and 3D printing-based tissue engineering, to enhance cell survival via cell-cell communication or cell-scaffold interactions. Because of its numerous applications, a combined therapeutic strategy that includes cell priming and tissue engineering technology is a promising therapeutic approach for cardiovascular regeneration.

Link: https://doi.org/10.1155/2017/3945403

Methuselah Foundation Launches Methuselah Fund

Those in the audience who have been members of this community for a while will know that the Methuselah Foundation has long acted as a form of incubator for biotechnology startups relevant to healthy life extension, albeit as a non-profit organization rather than the more usual for-profit incubator structure. The organization has undertaken this role in addition to funding some of the most promising research efforts in the field, such as the SENS rejuvenation biotechnology projects. This incubator work hasn't involved a large number of startups in total, since we are not yet either a vast or a wealthy community when considered in the grand scheme of things, and it is the case that the Methuselah Foundation is powered by our charitable donations. Nonetheless, with our support in past years, the Methuselah Foundation helped to launch the noted bioprinting company Organovo, and provided seed funding for Oisin Biotechnologies, pioneering a programmable gene therapy approach to clearance of senescent cells. Another company presently in the early stages of being shepherded by the Methuselah Foundation is Leucadia Therapeutics, working on a novel approach to clearing metabolic waste from the aged brain. There is a demonstrated track record of success here, moving in parallel to the progress in longevity science that has taken place in the laboratory.

The future isn't just a matter of funding research in non-profit organizations - at some point the leap must be made to a company and for-profit development. Given the growth in interest and funding for the treatment of aging as a medical condition that has taken place in recent years, and given that a number of professional venture funds dedicated to longevity science startups are now emerging, it is time for the Methuselah Foundation to formalize its efforts as a non-profit incubator of startups and pull in more philanthropic funding to help advance the state of the art. Hence David Gobel, Sergio Ruiz, and the other busy folk at the Methuselah Foundation have been working hard these past months to put together the Methuselah Fund. This initiative is tailored to the way that the Methuselah Foundation works with companies, an effective approach that has advanced the state of the field and moved us closer to the era of functional, widely available rejuvenation treatments. It is a novel fund structure, somewhat different from traditional investment vehicles, as much focused on the philanthropic mission as on the goal of producing increased value. This means Methuselah Foundation funding and guidance for the most promising science and scientific groups, to help them reach the point at which they can and should launch a company, followed by Methuselah Fund assistance in the business and venture worlds to help to make that company a success.

The Methuselah Fund is also tailored for the people in our community, those of us who have over the years gained the ability and willingness to donate or invest a few tens of thousands of dollars or more, but who cannot undertake the risk of investing in startups directly. The Methuselah Fund is presently open to anyone in our community who can make that level of commitment to support this expansion of non-profit work, not just professional investors. If you are a member of the Methuselah 300, you can complete your philanthropic pledge of $25,000 by putting the balance of pledged funds into the Methuselah Fund. This is not a standard venture fund, but like most venture funds it has a set lifespan, running until 2030. That is 13 years to achieve great things along the way by investing in and supporting the growth of companies that are pursuing the SENS vision of clearing out or repairing the molecular damage that causes aging and age-related disease - and not just by investing, but by actively helping these companies to succeed at every step along the way. When it comes to research and development for the treatment of aging and there are few networks as good as those surrounding the Methuselah Foundation and their allies, such as the SENS Research Foundation and other similar organizations.

Is Fight Aging! putting money into the Methuselah Fund? Yes, that is underway. I, like most people past the first few decades of life, have savings that become more or less accessible for use depending on the level of risk involved and the degree to which it is for profit investment versus philanthropic donation. Funding startups, as I have done of late, a little, is the most risky activity one can undertake. While it is technically for profit, it is far easier to think of it in the same way as a charitable donation to a research non-profit: it goes to fund a specific line of research, that is the primary goal, and anything more than that is pleasant but not expected. One shouldn't put money into startups that one cannot afford to lose. An structure like the Methuselah Fund will eventually be diversified across a number of companies, however, and therefore grow less risky over time. As an initiative that invests in startups, excellent track record of the Methuselah Foundation notwithstanding, its for-profit component still bears considerably more risk than the sort of diversified investments a good portfolio manager will tell you adopt - but no-one lives forever. Yet. If this interests you, by all means ask the Methuselah Foundation folk for a prospectus; when reading it, pay close attention to the way in which this is structured, and how that differs from the usual sort of venture fund. Contact information can be found in the interview below.

Tell us a little about the motivations here. Why the Methuselah Fund, and why now?

We want to accelerate mission results. As you know, Methuselah Foundation has been working hard during the last 16 years to extend the healthy human lifespan. We have long had the self-imposed goal of making 90 the new 50 by 2030 - it helps to inspire a sense of urgency appropriate to the great level of harm caused by aging. Since we now have only 13 years left to achieve this lofty but attainable goal, we will use an investment fund as a means to add fuel to the fire. Having this financial arm will allow us to exert our influence with companies with ground-breaking technology and approaches to medical issues, turning them towards the same mission as we have. Our ultimate goal is to make new medical treatments readily available to the public, as fast as possible, and thereby extending the healthy human lifespan.

Thus we are constructing a fund that will make it easier for companies to extend the healthy human life span. Unfortunately, history has shown it is often the case that when a venture capital approach is taken to increasing human longevity, the companies involved are required by the investors to pivot away from their original mission of treating aging and instead focus on an "FDA approved" disease such as cancer or type 2 diabetes. We want to avoid those outcomes. We do not believe in covenants that unduly restrict a company from going after therapies to treat the causes of aging. Beyond that, we are guided by Benefit Corporation principles, allowing us to create benefit for all stakeholders, not just the shareholders. This set of principles also gives us an expanded purpose beyond maximizing per-share value; we explicitly include general and specific public benefit. For example, if it makes better sense for a company to be merged in order to achieve our mission by 2030 and give up the potential for a billion dollar unicorn because it might kill the mission, we will prefer the mission. Unlike traditional venture capital, we are not afraid to leave a little money on the table when it benefits the real end goal of achieving more healthy life.

Why now? Because time is pressing. There are only 13 years left until 2030: 13 years to make 90 year-olds feel like they are 50 again. It is time to accelerate progress via the Methuselah Fund. The idea for this type of fund has been around for several years now. However, for it to be successful several things needed to happen, principally 1) emergence of an organization with a proven track record, 2) the development of a more mature view of longevity as a field of investment by the investment community. The Methuselah Foundation now has a significant tract record of positive investments (such as Organovo and Silverstone). These investments as a whole have been both mission-critical and highly profitable. That, compounded with leading the founding rounds of investments in Oisin Biotechnologies and Leucadia Therapeutics, has increased our investment experience and solidified our networks in the venture and scientific communities. Further, the investment community has matured, and events such as the founding of Apollo Ventures and the large investment in UNITY Biotechnology show that it is time to help steer the field to maximize progress towards our goal of far greater health in old age.

What are some of the irons you have in the fire at the moment?

The Methuselah Fund is our main iron in the fire at the moment and we are getting good traction. From a start-up standpoint, we are focusing our attention on two companies with the technology and knowledge to revolutionize their parts of the medical industry in ways relevant to our mission: Oisin Biotechnologies and Leucadia Therapeutics. We are constantly looking through the noise in search of the next shrewd investments, of course.

You've had a ringside seat and often a key role in many of the changes to happen in the aging research community this past fifteen years. What is your take on where things will go as we approach 2020?

Our hope is that as we approach and then pass 2020 we will start to see more products and treatments arriving in clinics via routes that circumvent the traditionally long, expensive, and heavily regulated paths to market, such as via medical tourism. Once this gets underway in any meaningful fashion, medical products of all sorts will have the added pressure of competitors being delivered in a fraction of the time, but with greater efficacy than ever before. Investors will finally see that investing in drugs that take decades to show returns is a bad business, and the whole house of cards will start to be dismantled into favor of something better. Given this process, everyday people will reap the benefits of: 1) cost savings due to a shorter incubation time for new products and 2) treatments arriving soon enough to matter for those who need them. Beyond 2020, we certainly hope to see new treatments that focus on preventing disease rather than merely patching it over: a medical reactionary culture will be overtaken by one of progressive better forms of prevention.

How will Methuselah Foundation change going forward, now that it is paired with Methuselah Fund?

The Methuselah Foundation will continue to organize research prizes and issue research grants as it has always done, with a focus on groups that can be aided in reaching the stage of commercial development. However, with the addition of the Methuselah Fund we will now have a powerful catalytic tool for our long-term mission, one that will bring in new resources and help to expand the breadth of these efforts.

You've often expressed a guiding vision for rejuvenation therapies of "clearing out the junk"; what does this mean in practice?

There are the scientific goals that, when reached as a whole, will make longer healthier human lifespans possible - see the SENS vision. We believe in making our goals easily understandable by all humans, however, since the cause of longer, healthier lives needs the backing of not just the scientific community but every one of us. The goal you mentioned is plain and simple: "Get the Crud Out". We call it "Crud" and not just "Junk" to make a point... no one likes crud! As we age, our bodies are weighed down by inefficiencies that create a slew of side-effects like inflammation and malfunctioning cells: this is easily understood. With "Get the Crud Out" we can cover the safe removal of senescent cells, broken mitochondria, and other destructive biological structures, as well as clearing out the various forms of waste products and byproducts (amyloid, lipofusin, cross-links, etc). That one goal covers a wide range of what we need to accomplish, makes the point, and expresses it simply enough to be a rallying slogan.

Among our other goals, which are equally important are: "New Parts for People," covering technologies such as bioprinting that will create new organs, bones, and vasculature; "Restore the Rivers," working to restore the circulatory system to full youthful competence and thus remove that contribution to conditions such as dementia and heart disease; "Debug the Code," to restore the informational integrity and viability of cells; "Restock the Shelves," investing in processes that replenish or restore stem cell and immune system populations; "Lust for Life," initiatives that restore the capacity for joy and resilience via rejuvenated senses and bodies. After all, what good would it be to live for hundreds of years without happiness, joy, and the fully functioning biology needed for both of those?

What can we in the community do to help make Methuselah Fund a success?

We are presently in the initial funding phase of the Methuselah Fund... the Founders' Round. We would love to talk to those who have the capacity to help back this exciting venture, or who know those who can. Interested parties can let us know and we will reach out with further details: please contact Sergio Ruiz at sergio@methuselahfund.com.

Arguing that Selection Pressure Diminishes with Age Even in Immortals

Evolutionary arguments relating to aging are tricky things, typically hinging on details that can be credibly argued either way. You might look at the recent resurrection of group selection in the service of explaining the origins of aging, for example. This is a much debated area of theory, with little in the way of true consensus on exactly why it is that near all species undergo aging. Fortunately, an explanation for aging isn't strictly necessary in order to make inroads into addressing the processes of aging as we observe them today, but evolutionary theories considered in general have in the past proven to be very helpful guides in a variety of medical research. The molecular biochemistry of living beings is vast and enormously complex, and researchers have to start their investigations somewhere.

As old as the evolutionary theory of senescence is its underlying and widespread tenet that senescence evolves because survivorship dwindles with age. Consequently, higher mortality should lead to more senescence. In contrast, several authors have indisputably shown over the last decades that this logic is incorrect. Yet, these results did not suffice to erase the prevailing misconception, which is problematic, because empirical studies keep on testing a theoretical prediction that is, as such, not predicted. What to do, when something repeatedly proven to be wrong is still taken to be right? Here we attempt to advance understanding of the evolutionary theories of aging conditional on survivorship. Clearly, survivorship falls over age, and clearly adding some fixed amount of mortality at every age makes survivorship fall off more steeply. But such a shift in mortality merely reduces fitness; it does not change the selection gradients over the fitness landscape. The selection gradients still decline following the same pattern as in the absence of such mortality; selection does not favor young over old ages more or less strongly than before.

When it comes to understanding why we age, the rarity of survival to old age alone has long served as the explanation for declining selection gradients. This seems curious, because life is driven by birth and death together. Why should one side - survivorship - suffice to explain fundamental patterns of life, such as aging? We have demonstrated that reproduction plays an important role. Births keep on adding new individuals to the population, fueling a population growth factor that reduces the share of old organisms in the population. Even in the absence of death, as we demonstrate, births are enough to achieve declining selection gradients. Mortality is not the all-important driver of selection gradients.

We argue that older organisms have already produced a larger share of their total lifetime reproduction. Therefore a progressively smaller proportion of total production is affected by anything that happens to an organism at higher ages, and the organism will already have passed on its genes. Whether a change at some age affects evolution to a smaller or larger degree hinges not on survivorship per se, but on the relative abundance of individuals and their reproductive values. Provided the population is non-decreasing, the stable age distribution is always dominated by younger individuals over older individuals as a result of reproduction. This is true even in the hypothetical case of zero mortality. Survivorship can be changed by an age independent mortality term without affecting the selection gradients. Similarly, changes in age independent mortality leave optimal strategies unaffected.

The arguments laid out in this paper have theoretical and practical consequences. Empirical research has shown little support for the "central prediction" of the evolutionary theory of senescence, that a higher level of extrinsic mortality (predators, harsh environments, laboratory manipulations) should lead to a higher rate of senescence. A number of authors have called for a more involved theory of senescence, in which mortality is state dependent, and/or in which density effects play a prominent role. The results derived here and elsewhere make clear why there is little support for the central prediction. It is not just that this prediction is not born out in biological reality; life history theory simply makes no such prediction. After decades of theoretical work, we are still challenged to develop theory that provides more than an incidental match with the data. Our results corroborate the need for theory that is more involved; it may include combinations of age- and stage-specific mortality, density effects, and/or interaction mortality. Such a theory should involve mechanisms of senescence, as evolutionary pressures alone are only half the story.

Link: https://dx.doi.org/10.1007/s11692-016-9385-4

Results from a Human Trial of Stem Cell Therapy Following Stroke

For the past few years, researchers have been running a trial of a first generation stem cell therapy for stroke patients. This used stem cell lines cultured from donors rather than from the patients. As is the case for some other forms of cell therapy, the resulting benefits appear linked to reduced inflammation rather than any other effects of the transplanted cells. Otherwise, the effects on patients were not as large as hoped would be achieved via this type of approach.

A trial looking at whether a single dose of millions of adult, bone-marrow-derived stem cells can aid stroke recovery indicates it's safe and well-tolerated by patients but may not significantly improve their recovery within the first three months. However, the trial does provide evidence that giving the therapy early - within the first 36 hours after stroke symptoms surface - may enhance physical recovery by reducing destructive inflammation as well as the risk for serious infections and that these benefits might continue to surface many months down the road. "There is solid evidence from our basic science work and now some indicators from this phase 2 patient trial that giving these stem cells can safely help dial back the body's immune response to stroke injury that can ultimately further damage the brain and body."

The study at 33 centers in the United States and the United Kingdom from October 2011 to December 2015 included 129 adults with moderately severe strokes. A dose of 400 million cells were given to a handful of patients to establish safety, the dose was then increased to 1,200 million cells for the majority of patients. About half of patients received a single dose of the stem cells while the remainder received placebo. Patients in both arms were able to also have received standard stroke therapies. While the study made several adjustments along the way to enable better enrollment, it was an early adjustment in the timeframe for giving the therapy that may have impacted results. Trial leaders extended the timeframe for therapy from the original 24 to 36 hours - which was suggested by previous animal studies - to 24 to 48 hours. That adjustment was in response to limited hours at some centers to thaw and otherwise prepare the cells for patients as they qualified for the study. Now cell developers have reduced thaw times from 6 hours to 30 minutes and made the process much easier, which should enable tighter timeframes for giving the treatment moving forward.

Although the primary analysis of results was done at 90 days, about 80 percent of study participants were followed for a full year. It was those longer-term results, particularly in the small number of patients who got therapy early, that suggested the cell therapy group might be more likely to continue to recover, with reduced disability and fewer infections one year out than the placebo group. The multipotent cells, dubbed MultiStem, were developed by the international biotechnology company Athersys Inc., which also funded the clinical trial. Doses given in the study were the largest ever given in a human cell therapy trial.

Researchers who have studied the cells believe they primarily work by modulating the body's immune response, which can go a bit haywire following a stroke. An immune response is definitely needed to help the brain heal and to remove debris generated by dead or damaged tissue. But there also may be a secondary response that includes immune organs like the spleen, beginning to shrink in size within the first hours after symptoms of stroke. "Some inflammation is good, but in a big stroke, it almost always overshoots. We think this secondary neuroinflammatory process is preventing the natural healing tendencies of the body. We think cell therapy prevents this early egress of cells from the spleen that go to the brain and, by doing that, they also prevent the later exhaustion of the spleen and immune system."

Link: http://jagwire.augusta.edu/archives/42526

Predicting Mortality from Ten DNA Methylation Sites

A growing number of researchers are developing and testing various implementations of a DNA methylation biomarker of aging. There is even a US company offering a low-cost test for those who want to give it a try. The quality of resulting data and degree of testing and validation accomplished for these various approaches is quite varied. Some provide only loose correlations with mortality and life expectancy, while others produce estimates of age with a five year margin of error. This depends as much on the intentions of the research team as on the details of construction of the biomarker. Not every team has the funding or time to prove their case very rigorously in large data sets, versus creating an initial proof of concept to show that their approach to the biomarker is worthy of that funding and time.

How do these DNA methylation biomarkers differ form one another? DNA methylation is a form of epigenetic marker, a molecular decoration on DNA that can occur at any CpG site in the genome. This mark determines the pace at which proteins are produced from the related genetic blueprint, which genes are active and which are silent, and is one part of the many regulatory mechanisms that drive changes in cell behavior. All of the switches and dials inside the machinery of a cell can be traced back through chains of cause and consequence to a matter of how much of a particular protein is being produced. A cell's epigenetic configuration is a reaction to the circumstances that cell finds itself in. Some portion of that set of circumstances is due to the age of the tissue within which the cell is situated. Since we all age for the same underlying reasons, we all accumulate the same molecular damage, some of the epigenetic changes that occur with aging are shared, and can in principle indicate the level of damage present in an individual's tissues - a measure of biological age. But which epigenetic marks? That is the question. The choice of CpG sites to evaluate, the weight given in the final score to any one site, and the way in which that score is calibrated against test data: all these are ways in which DNA methylation biomarkers can differ from one another.

The development of at least one reliable, accurate biomarker of aging is an important step in the infrastructure needed for rapid progress in rejuvenation biotechnologies. For approaches based on the SENS vision of damage repair, it is straightforward enough to determine how effective a therapy is within its own paradigm. For example, given the ability to clear senescent cells from aged tissues, researchers can immediately follow such a treatment by measuring how great a percentage of senescent cells have been cleared. A senescent cell clearance therapy that clears half of all such cells is better than one that only clears a quarter of them. That doesn't tell us how great an extension of healthy life span will result from the treatment, however. At the present time the only way to assess that outcome is to wait and see. Waiting to see is, unfortunately, expensive and slow: it is an investment of years and millions of dollars in any earnest study, even in mice. That slows down the pace of progress. An independent biomarker such as DNA methylation might be able to short-cut that waiting game by providing a rapid measure of the degree of rejuvenation achieved immediately following the application of an intervention to treat the causes of aging.

DNA labels predict mortality

What does the methylation status in the DNA reveal about a person's health, his or her susceptibility to disease or, in short, an individual's mortality risk? Researchers investigated the cases of 1,900 participants of two epidemiological studies called ESTHER and KORA. They used DNA from blood cells as the basis of their investigation. All study subjects were older adults and had provided blood samples when they entered the study. This was up to 14 years ago and many of them had died since then. Methyl groups are only attached to a certain combination of DNA building blocks called CpGs. For almost 500,000 of these positions, the researchers analyzed whether their methylation levels revealed a statistical link to survival. After rigorous statistical review, it finally boiled down to 58 CpGs that showed a strong correlation between methylation status and mortality.

These 58 CpGs were all located in genomic regions for which an association with various diseases is well documented. Interestingly, 22 of the 58 CpGs were identical with methylation positions that the researchers had recently found in a study on the epigenetic impacts of smoking. Of all health risk factors, smoking hence appears to leave the strongest tracks in the genome. "The good news is that the level of DNA methylation is not written in stone. Unlike mutations in the DNA building units, it is reversible. That means, for example, that an unfavorable methylation status may change after smoking cessation and the mortality risk may drop again significantly."

Of the 58 CpGs, the scientists selected those ten with the strongest correlation with mortality. This epigenetic risk profile alone enabled them to predict the so-called all-cause mortality (cancer, cardiovascular diseases, and others). Study participants whose genome exhibited an "unfavorable" methylation status at five or more of these sites had a risk of death within the 14-year observation period that was seven times that of study participants whose methylation at these positions showed no abnormalities. "We were surprised that the methylation status of only ten positions of our genome correlates so strongly with all-cause mortality. We found even stronger links to mortality from cardiovascular diseases. Now it is important to find out which prevention measures are most effective to achieve a beneficial impact on the methylation profile and mortality."

DNA methylation signatures in peripheral blood strongly predict all-cause mortality

DNA methylation (DNAm) has been revealed to play a role in various diseases. Here we performed epigenome-wide screening and validation to identify mortality-related DNAm signatures in a general population-based cohort with up to 14 years follow-up. In the discovery panel in a case-cohort approach, 11,063 CpGs reach genome-wide significance. 58 CpGs, mapping to 38 well-known disease-related genes and 14 intergenic regions, are confirmed in a validation panel. A mortality risk score based on ten selected CpGs exhibits strong association with all-cause mortality, showing hazard ratios of 2.16 (1.10-4.24), 3.42 (1.81-6.46) and 7.36 (3.69-14.68), respectively, for participants with scores of 1, 2-5 and 5+ compared with a score of 0. These associations are confirmed in an independent cohort and are independent from the 'epigenetic clock'. In conclusion, DNAm of multiple disease-related genes are strongly linked to mortality outcomes.

The recently established epigenetic clock (DNAm age) has received growing attention as an increasing number of studies have uncovered it to be a proxy of biological ageing and thus potentially providing a measure for assessing health and mortality. Intriguingly, we targeted mortality-related DNAm changes and did not find any overlap with previously established CpGs that are used to determine the DNAm age. Our findings are in line with evidence, suggesting that DNAm involved in ageing or health-related outcomes are mostly regulated by DNAm regions other than the established age-related DNAm. The difference could also plausibly result from the fact that DNAm age was originally trained as precisely as possible to track chronological age and might thus be more indicative of natural ageing beyond the effect of disease, as exemplified by the much stronger association of DNAm age with mortality in oldest population (mean age 86.1 years) to whom common chronic diseases, such as CVD and cancer, might not continue to pose predominant risks.

The Trans-NIH Geroscience Interest Group

One of the active formal networks for scientists interested in treating aging as a medical condition is the Trans-NIH Geroscience Interest Group (GSIG), with a focus on public funded research and research groups. The thrust of their efforts is to achieve a modest slowing of the aging process by adjusting the operation of metabolism so as to slow down the rate at which the molecular damage of aging accumulates. These are generally people who - in public at least - do not support SENS rejuvenation research and the goal of repairing the cell and tissue damage that causes aging in order to reverse the progression of aging. The sort of future they envisage is one of slightly longer human life spans achieved through the use of calorie restriction mimetic drugs and the like, and so the interventions supported include the metformin trial, investigations of rapamycin, and so forth, nothing that is at all likely to produce sizable benefits for older people.

Insofar as useful outcomes result from the GSIG, I think it likely that some will be indirect, in the sense of obtaining greater support for treating aging rather than the effects of aging, that will in turn translate into more funding for projects like the SENS programs that can make a large difference. Secondly, direct benefits may emerge from the GSIG focus on biomarkers of aging, assuming that the DNA methylation approach isn't already good enough for practical purposes, and that other technologies must be explored. Good biomarkers of biological age are necessary for the rapid and cost-effective development of rejuvenation therapies, as when the only viable way to determine effectiveness is to try a treatment in mice and then wait a few years, progress is necessarily slow and expensive. With a biomarker, however, such a trial might be accomplished in a few weeks or months and at a much lower cost, assessing the degree of rejuvenation achieved with a measurement soon after treatment.

During a 2010 workshop organized by the Alliance for Aging Research, a discussion was held about the idea that aging is at the core of all chronic diseases, and one of us mentioned, without much pre-conceptualization, that since aging biology is at the core of all the diseases that concern them, then every institute within the NIH should have a Division of Aging Biology. The idea remained and over discussions in the ensuing months, this concept was further developed as a possible activity to be proposed across the entire NIH. As we refined the ideas and prepared to engage others, it became obvious that geroscience was a proper name for the initiative. Thus was born the Trans-NIH Geroscience Interest Group, GSIG.

Interestingly, the concepts of geroscience have long been understood both by scientists and the general public, as well as literature and the arts. However, the concept was slow in gaining recognition in medical spheres because of the ingrained notion that age is not a modifiable factor. While this is obviously true for chronological age (as the passage of time) it is also well recognized that good health at older ages can be attained by relatively simple interventions (which as behavioral changes, appear difficult for many people). Acceptance of age as the major risk factor for chronic diseases is implicit in the recommendations we receive if we visit a medical doctor for any malady: in addition to disease-specific interventions (statins, metformin, antidepressants), we are often counseled to "eat well, exercise moderately, and refrain from smoking." These are non-specific recommendations aimed at "healthier aging," but physicians seem loath to say so directly.

What has changed the perceptions is the astonishing advances made in the last couple of decades by scientists focused on understanding the basic biological underpinnings of the aging process, independently of disease. This has led to a few publications, including those from the GSIG, that have attempted to classify the main hallmarks or pillars currently believed to be the main drivers of the aging process. These conceptual advances have worked synergistically with reports from the NIA-supported Interventions Testing Program, which aims to test, in a variety of animal models, mostly pharmacological interventions that lead to an increase in both lifespan and healthspan.

Acceptance of the geroscience concept within the NIH proceeded at such a fast pace that an action plan was much less developed than the conceptual arguments used to form the group. An important strategic point was to keep the initial goals simple and attainable. This required a focus primarily on informational activities that would not require significant dollar investments on the part of participating institutes. Also, because the entire concept had been developed as a means to capitalize on the advances in basic aging research, the initial goal statement indicated that the focus was to be on basic biology, although we recognized the translational value of the effort. Current efforts are focused primarily on three areas where the GSIG recognizes an urgent need for further research: development of more appropriate animal models, enhancing the focus of geroscience on health irrespective of disease, and identification of suitable molecular and cellular biomarkers of the aging process. Taken together, these efforts aim at developing a deeper understanding of the basic biology driving all chronic diseases, and harnessing that knowledge for the betterment of health and well-being.

Link: https://dx.doi.org/10.1007/s11357-016-9954-6

Digging in to the Mechanisms of A2E in Macular Degeneration

An accumulation of the metabolic waste compound A2E in the retina is associated with the progression of degenerative blindness via conditions such as macular degeneration, and there is strong indirect evidence for it to be a cause of the condition. This is one of numerous forms of waste that accumulate to form lipofuscin deposits inside and outside cells in the retina, but most likely the most important form. The easiest way to prove that causation beyond doubt, and hopefully also develop therapies that actually reverse retinal damage, is to selectively break down and remove A2E. An effort based on drug candidates developed at the SENS Research Foundation is currently underway at Ichor Therapeutics, but sadly this class of intervention, addressing root causes, has never been a priority in the research community as a whole. That point is somewhat illustrated in this open access paper, in which researchers investigate the role of A2E, and conclude by deciding that one of the downstream changes caused by A2E should be a target for therapy rather than the A2E accumulation itself.

Age-related macular degeneration (ARMD) is the leading cause of vision loss in developed countries. Hallmarks of the disease are well known; indeed, this pathology is characterized by lipofuscin accumulation, is principally composed of lipid-containing residues of lysosomal digestion. The N-retinyl-N-retinylidene ethanolamine (A2E) retinoid which is thought to be a cytotoxic component for retinal pigment epithelium (RPE) is the best-characterized component of lipofuscin so far. Even if no direct correlation between A2E spatial distribution and lipofuscin fluorescence has been established in aged human RPE, modified forms or metabolites of A2E could be involved in ARMD pathology.

Mitogen-activated protein kinase (MAPK) pathways have been involved in many pathologies, but not in ARMD. Therefore, we wanted to analyze the effects of A2E on MAPKs in polarized ARPE19 and isolated mouse RPE cells. We showed that long-term exposure of polarized ARPE19 cells to low A2E dose induces a strong decrease of the extracellular signal-regulated kinases' (ERK1/2) activity. In addition, we showed that A2E, via ERK1/2 decrease, induces a significant decrease of the retinal pigment epithelium-specific protein 65 kDa (RPE65) expression in ARPE19 cells and isolated mouse RPE. In the meantime, we showed that the decrease of ERK1/2 activity mediates an increase of basic fibroblast growth factor (bFGF) mRNA expression and secretion that induces an increase in phagocytosis via a paracrine effect. We suggest that the accumulation of deposits coming from outer segments (OS) could be explained by both an increase of bFGF-induced phagocytosis and by the decrease of clearance by A2E. The bFGF angiogenic protein may therefore be an attractive target to treat ARMD.

Link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5331064/

Functional Tooth Regrowth Demonstrated in a Canine Model

There has been considerable progress over the past decade towards the regrowth or tissue engineering of adult teeth via a number of different mechanisms. These include growing a tooth entirely outside the body, starting from a few cells, an approach that has a range of associated challenges regarding how to guide the growing tissues to form the right shape. Some years back researchers demonstrated a fairly brute force method of providing that guidance in tissue engineered mouse teeth, to pick one example. Then there is the alternative approach in which researchers attempt to create the seed of a tooth, the tooth germ, a collection of cells as similar as possible to those that occur naturally when a tooth grows. The idea here is to enlist the existing environment of the jaw and gum to guide growth of a new tooth; if the artificial seed is close enough to the natural equivalent, then the end result will be a correctly formed tooth. The paper quoted below is an example of the state of the art in this latter approach to adult tooth regrowth: researchers have pushed towards larger animal models, and can now fairly reliably induce the growth of functional replacement adult teeth in canines.

If you read the paper closely, the researchers are still relying heavily on natural tissues to source the relevant cells to make up the seed for a new tooth. They report on mining the naturally grown teeth of animal models in order to demonstrate that suitably arranged cell combinations will then go on to grow new teeth in those same animals when implanted into the jaw. Future work will involve establishing reliable methods of creating patient-matched cells to order, such as via reprogramming of a patient cells sample into induced pluripotent stem cells, and then differentiating the needed cell types from that pluripotent lineage. Not all of the required recipes for the cell types of interest have yet been established, however, so there is a significant amount of work left to be accomplished. Once done, however, that will open the doors to further progress.

How long before we humans will benefit from this sort of approach to tooth regeneration? Dentistry is somewhat less oppressively regulated than the rest of medicine in much of the world, the consequence of a long history of somewhat arbitrary separation of disciplines, and so new innovations in dentistry tend to arrive in clinics more rapidly. If researchers are just now growing new teeth in dogs after ten years of work in bioreactors and rodents, then another decade to reach clinical applications is a fair guess. It is an open question as to how well it will work in older individuals, however. Do old people still exhibit enough of the same guiding signals and cellular behavior in gums and jaw bones? It is well known that regeneration in general declines with age, for reasons that include failing stem cell activity and altered cell signaling that occurs in reaction to rising levels of molecular damage in tissues. The fastest way to find out is to try and see, but we can also survey the sort of work on aging and stem cell biochemistry that is currently taking place in relation to the development of stem cell therapies. That will provide some idea of the additional time and cost imposed by trying to make things work well in older people. There are differences between old tissues and young tissues, and in many cases they are significant enough to require a modified or alternative approach.

Practical whole-tooth restoration utilizing autologous bioengineered tooth germ transplantation in a postnatal canine model

In this study, we demonstrated functional tooth restoration after transplanting bioengineered tooth germ in a postnatal large-animal model. The bioengineered tooth, which was reconstructed using canine permanent tooth germ, developed with the correct tooth structure after autologous transplantation into the jawbone. We also determined that the bioengineered tooth erupted into the oral cavity with the features of proper tooth tissue formation and restored physiological tooth function, such as the response to orthodontic mechanical force. This study represents a substantial advancement in organ replacement therapy through the transplantation of bioengineered organ germ as a practical model for future whole-organ regeneration.

Whole-tooth replacement therapy holds great promise for the replacement of lost teeth by reconstructing a fully functional bioengineered tooth using three-dimensional cell manipulation in vitro. It is anticipated that bioengineering technology will ultimately enable the reconstruction of fully functional organs in vitro through the proper arrangement of epithelial and mesenchymal cell components. Many researchers have attempted to generate bioengineered tooth germ using epithelial and mesenchymal cells from embryonic tooth germ or postnatal tooth germ from various species, including mice, rats and swine. With the goal of precisely replicating the developmental processes that occur in organogenesis, the study of an in vitro three-dimensional cell manipulation method called the bioengineered organ germ method has been recently reported. However, additional evidence of the practical application to human medicine is required to demonstrate the generation of bioengineered tooth germ using postnatal cell sources in a large-animal model.

To achieve whole-tooth restoration in humans, it is desirable to autologously transplant bioengineered tooth germ reconstructed using a patient's own stem cells to prevent immunological rejection, and it is necessary to first establish an autologous tooth germ transplantation system in a large-animal model. We therefore investigated whether the canine bioengineered tooth germ reconstructed using epithelial and mesenchymal components isolated from individual tooth germs could develop after autologous transplantation into the jawbone. We demonstrated that a bioengineered tooth reconstructed from canine permanent tooth germ reproduced the correct tooth structure, including calcified components and enamel and dentin microstructure. Furthermore, the erupted bioengineered tooth had a single-root shape with the proper periodontal tissue structure, and it achieved physiological tooth function in terms of biological response to mechanical stress equivalent to the function of a natural tooth.

If a large-scale culture of epithelium/mesenchymal tooth germ cells were to be established in future, this bioengineered tooth technology would be able to treat a large number of missing teeth. Elderly patients, however, do not have a developing tooth germ that can be used for the reconstruction of bioengineered tooth germ in the patient's own jaw. In the dental field, recent stem cell biology studies have led to the identification of dental stem cells based on tooth organogenesis for tooth tissue regeneration and tooth regenerative therapy. Although these stem cells would be valuable cell sources for stem cell transplantation therapy aimed toward dental tissue regeneration, the tooth inductive potential cells, which can replicate an epithelial-mesenchymal interaction for whole-tooth replacement, has not yet been identified.

A Tour of Some of the Molecular Damage Involved in Aging

The intricate molecular machinery found in cells only functions correctly when it is undamaged, meaning formed of the right atoms and bonds, and that often sizable structure correctly arranged into a particular three-dimensional shape. A cell is essentially a liquid bag of molecules that are constantly coming into contact with one another, however. Large numbers of these molecules react in inappropriate ways or become misfolded, and so a cell incorporates layer upon layer of quality control mechanisms, each of which strives to ensure that cellular machinery remains correct in form and structure. Broken parts are aggressively removed and recycled, but nonetheless some damage inevitably slips through. Aging itself is essentially a process of damage accumulation, at root an accumulation of unwanted and malformed molecules, and then the chain of unfortunate consequences that follows from that state of damage. This open access review covers some of the forms of molecular damage involved in the aging process:

The idea that aging results from the gradual accumulation of molecular damage is deeply rooted in the aging research field, although it can appear in verbal disguises so different as to seem conceptually independent. However, damage is implicit to DNA in the somatic mutation theory of aging, to the extracellular matrix proteins in the cross-linking theory, and to phospholipids in the membrane theory. The free-radical theory implies that reactive oxygen species (ROS) are responsible for damage, and the carbonyl-stress theory blames free carbonyls for it. With regard to the last two theories, the former celebrates its 60th anniversary this year and remains the most influential in the "damage field", and the latter is its extension insofar as it attributes the origin of many of the most noxious molecular species to the free-radical oxidation of metabolites initially devoid of highly reactive carbonyl moieties.

In a metabolic system, not only spontaneous decay and degradation reactions, such as hydrolysis, oxidation, and racemization, but also spontaneous multistage synthetic processes take place. Can the products formed in this way be regarded as metabolites in a strict sense? They are not generated by enzymes, are not used purposefully, and are often hazardous. One way to view them is as damaged metabolites. For example, 5-Scysteinyldopamine is a damaged form of cysteine or dopamine. A related way to conceptualize this phenomenon is to view it as a sort of 'underside' of metabolism or 'parametabolism'. A conceptually similar but more general approach is to regard such unwanted products as a manifestation of the imperfectness of metabolism and its components, which together produce deleterious effects at all levels of biological organization. The totality of such effects has been described as the "deleteriome", which expands with age and represents the biological age of an organism. One way to increasing the deleteriome is by the spontaneous polymerization of damaged metabolites, such as catecholamine-derived quinones. In reality, such polymerization occurs in a milieu abundant in proteins, which are included in the resulting agglomerates, wherein they become covalently modified and misfolded and thus made prone to aggregation. Altogether, this leads to the accumulation of polymers of (damaged) metabolites associated with protein aggregates in the form of lipofuscin, neuromelanin, and other forms often referred to as waste.

A good case for applying the ideas discussed above to a specific situation is provided by bisretinyls, the major constituents of lipofuscin accumulated in the pigmented epithelium of the eye. Bisretinyls are byproducts of visual cycle biochemistry. Without delving into important details and conflicting views, it is sufficient in the present context to point out that the functional demands of light perception ensure that the aldehyde retinal is constantly present free in an environment rich in ethanolamine moieties. The result is the formation of retinyl dimer and a host of related compounds accumulating in photoreceptor membranes, which are constantly shed off to be phagocytized by pigmented epithelium cells. The poorly degradable retinal dimer and related products form lipofuscin deposits in pigmented cells and thus increase the risk of macular degeneration, the most common form of age-related vision loss.

Several lessons follow from the above case. First, damage accumulation results from normal functions, and the pathways of damage formation may become clear only after the molecular details of normal functions become known. Second, damage manifests itself in a functionally significant manner at ages rarely achievable in the wild under the conditions in which the species in question evolved. Therefore, there was no selection pressure towards the prevention of accumulation of this sort of damage. However, there was pressure towards preventing any immediate damage, even at the expense of later adverse consequences. In fact, lipofuscin accumulation in pigmented epithelium is a consequence of clearing of photoreceptor cell membranes from damage caused by retinal liberated in the course of light perception. Third, via a series of transitions through rapidly turning-over cell constituents, damage finally accrues as a slowly turning-over material in the nonrenewable component of a functional system where the deposits of damaged metabolites accumulate.

Spontaneous chemical reactions between metabolites are often labeled with proper names, such as Schiff, Pictet-Spengler, Amadori, Mannich, or Michael, just because they are typical and will take place wherever the respective reactants come together. Thus, from the chemical point of view, a metabolic system cannot but be plagued with numerous short-circuits, leaks and other adverse concomitants of metabolism. Unwanted reactions of this sort give rise to diverse damage products that increase in number and abundance with age and are adjusted (with regard to both composition and rate of increase with age) by interventions that affect lifespan. These reactions in their entirety are sufficient to cause what is generally termed aging.

Link: http://www.jbc.org/cgi/doi/10.1074/jbc.R116.751164

A High Level View of Senescent Cell Clearance

This is a better than average popular science article on turning back the progression of aging by removing senescent cells from aged tissues; certainly the bar for article quality set by the mainstream press isn't high, but it is always pleasant to see more authors clearing it. One point worth noting in response to this piece is that we really have little idea as to how the life extension observed in mice lacking senescent cells will scale in humans. Near all methods of extending life in mice to date have been based on modestly slowing aging, changing the operation of metabolism to reduce the rate at which molecular damage accrues. Short-lived species like mice have a much greater response to this sort of thing than do humans, demonstrated when we compare the effects of calorie restriction and growth hormone receptor loss of function mutations. In mice these can extend life by as much as half again, but if that was the case in humans, we'd have certainly noticed by now. Clearing senescent cells is a completely different form of therapy, however, a type of damage repair carried out intermittently rather than an ongoing slowing of damage. I know of no such approach that has been tried in both mice and humans, and thus there is no basis for comparison.

Imagine a world where you could take just a single pill for the treatment or prevention of several age-related diseases. Although still in the realms of science fiction, accumulating scientific data now suggests that despite their biological differences a variety of these diseases share a common cause: senescent cells. This has led scientists to find drugs that can destroy these cells. When cells become damaged, they either self-destruct (apoptosis) or they lose their ability to grow and remain stuck within the body. These are the non-growing senescent cells that no longer carry out their tasks properly. They spew out chemicals that cause damage to cells nearby, sometimes turning them into "zombies" - hence why they are sometimes referred to as "zombie cells". Eventually, the damage builds up so much that the function of bodily organs and tissues, such as skin and muscle, becomes impaired. At this point, we identify the changes as disease.

In 2011 and in 2016, researchers showed, through the use of genetically engineered (transgenic) mice, that the removal of senescent cells reduced cancer formation, delayed ageing and protected the mice against age-related diseases. The mice also lived 25% longer, on average. A similar result in humans would mean an increase in life expectancy from 80 years to 100 years. It was proof-of-principle studies like these that laid the groundwork and inspired other researchers to build on these findings. It is not known how many senescent cells need to be present to cause damage to the body, but the harmful effects of the chemicals they release can spread quickly. A few zombie cells may have a huge impact. Drugs for specifically killing senescent cells in order to extinguish their destructive force have recently been revealed and tested on mice. The collective term for these drugs is "senolytics".

In 2016, two research groups independently published findings on the discovery of two new senolytic drugs which target proteins responsible for protecting senescent cells from cell death. Research showed that the drug ABT-263 (Navitoclax) could selectively kill senescent cells in mice, making aged tissues young again. And scientists have also used the drug ABT-737 to kill senescent cells in the lungs and skin of mice. There has also been a lot of interest in the role of senescent cells in pulmonary diseases caused by damage to the lungs. In late 2016, scientists showed that the removal of senescent cells using genetically engineered mice greatly restored lung function in old mice. In light of these accumulating and highly promising findings, a number of start-up biotechnology companies have been created to exploit the health benefits of targeting senescent cells. Probably the most well funded is UNITY Biotechnology in the US which raised US$116M for research and development.

Link: https://theconversation.com/killing-zombie-cells-to-improve-health-in-old-age-74557

More on PCSK9 Inhibition to Dramatically Reduce Cholesterol Levels, Lowering the Risk of Later Cardiovascular Disease

There is good evidence for at least some methods of achieving dramatic reductions in blood cholesterol in humans to be safe and reduce the risk of age-related cardiovascular issues. To pick one of the underlying mechanisms involved in these benefits, the common age-related condition of atherosclerosis is at root caused by interactions between damaged cholesterol and the cells of blood vessel walls. Cells become irritated by the presence of that cholesterol, and this begins a series of overreactions and unfortunate events that leads to the generation of fatty plaques that narrow blood vessels and weaken blood vessel walls. In conjunction with the raised blood pressure present in older individuals, this eventually leads to the dramatic structural failure of a stroke or heart attack, when a large blood vessel is blocked or ruptures. If there is less cholesterol in the bloodstream, however, the whole chain of cause and effect slows down. That slowing isn't as good as fixing the issue, such as by effectively sabotaging any one of the bad cellular behaviors that combine to lead to the growth of plaques, but it is certainly a lot better than nothing.

Statins are the obvious item to point out when thinking about cholesterol, aging, and cardiovascular disease. The widespread use of this class of drug has done much to reduce the incidence and mortality of cardiovascular disease. These days, however, researchers are looking into more targeted means of reducing cholesterol levels, forms of therapy that suppress specific genes to achieve much larger reductions than is possible with statins. There are a number potential targets for gene therapies, RNA interference approaches, and the like, such as an ASGR1 mutation that occurs in small number of humans, who have less cholesterol and much lower rates of atherosclerosis. The story is much the same for an ANGPTL4 mutation, also present in a small number of people and associated with significantly reduced cholesterol and cardiovascular risk. For today, however, I'll note a brace of publicity materials on recent attempts to target PCSK9 with the aim of permanently lowering blood cholesterol by a large amount. Several distinct teams appear to have timed their press for the same scientific conference, so all the results appeared in public at much the same time.

New 'gene silencer' drug injections reduce cholesterol by 50% in early research

The first in a new class of gene-silencing drugs, known as inclisiran, has halved cholesterol levels in patients at risk of cardiovascular disease. The findings come from the largest trial yet to test the safety and effectiveness of this kind of therapy. The technique, known as RNA interference (RNAi) therapy, essentially 'switches off' one of the genes responsible for elevated cholesterol, PCSK9. The twice-a-year treatment could be safely given with or without statins, depending on individual patient needs. Eventually, inclisiran could help to reduce the risk of heart attacks and stroke related to high cholesterol. "We appear to have found a versatile, easy-to-take, safe, treatment that provides sustained lowering of cholesterol levels and is therefore likely to reduce the risk of cardiovascular disease, heart attacks, and stroke. These reductions are over and above what can be already be achieved with statins alone or statins plus ezetemibe, another class of cholesterol-lowering drug."

In the study, researchers gave 497 patients with high cholesterol and at high risk of cardiovascular disease either inclisiran at varying doses, or placebo. Seventy-three per cent of these patients were already taking statins, and 31 per cent were taking ezetimibe. Participants, who were recruited from Canada, USA, Germany, Netherlands, and the UK, were excluded if they were taking monoclonal antibodies for cholesterol lowering. Patients were given different doses of inclisiran or placebo via subcutaneous injection, either via a single dose, or via a dose on day one and another at three months. They were followed up regularly for a subsequent eight months and tested for blood cholesterol and side effects. The researchers found that just one month after receiving a single treatment of inclisiran, participants' LDL cholesterol levels had reduced by up to 51 per cent.

PCSK9 Inhibitor Evolocumab Significantly Reduces Adverse Cardiovascular Events When Added to Statin Therapy With No Major Safety Concerns

A new class of cholesterol lowering drugs known as PCSK9 inhibitors has emerged as an effective treatment for drastically lowering LDL cholesterol beyond what is possible with statin therapy alone. Previous research demonstrated that evolocumab, a member of this new class of drugs, effectively reduces LDL cholesterol by approximately 60 percent. Evolocumab is a fully human monoclonal antibody that works by blocking proprotein convertase subtilisin-kexin 9 (PCSK9), a protein that reduces the liver's ability to remove LDL cholesterol from the blood. The FOURIER trial (Further Cardiovascular OUtcomes Research with PCSK9 Inhibition in subjects with Elevated Risk) was designed to determine whether evolocumab, when added to statin therapy, would reduce adverse cardiovascular events.

In this randomized, double-blind, placebo-controlled multinational clinical trial, 27,564 patients aged 40-85 were studied. All trial participants had stable atherosclerotic vascular disease, defined as a medical history of heart attack, stroke or symptomatic peripheral artery disease. On a background of high or moderate intensity statin therapy patients had a LDL cholesterol level of at least 70 mg/dl. Patients received either evolocumab (140mg every two weeks or 420mg every month) or placebo. Similar to data from previous lipid lowering trials, researchers report that evolocumab reduced LDL cholesterol by 59 percent, in this case from a median of 92 mg/dL to a median of 30 mg/dL. The LDL cholesterol lowering effect remained constant over the duration of the trial.

Researchers report that patients treated with evolocumab had a 15 percent reduction in the risk of major cardiovascular events, defined as the composite of cardiovascular death, myocardial infarction, stroke, hospitalization for unstable angina, or coronary revascularization (occurring in 9.8 percent of patients treated with evolocumab vs. 11.3 percent of patients treated with placebo). Additionally, evolocumab reduced the more serious key secondary endpoint, which was a composite of heart attack, stroke or cardiovascular death, by 20 percent (occurring in 7.9 percent of patients treated with evolocumab vs. 9.9 percent in the placebo group). This reduction in risk improved over time, increasing from 16 percent in the first year to 25 percent after the first year.

PCSK9 Inhibitior Bococizumab Produces Varying Results

New results from the clinical trial program, SPIRE (Studies of PCSK9 Inhibition and the Reduction of Vascular Events), which sought to determine the effect of bococizumab, a PCSK9 inhibitor, on LDL cholesterol levels and clinical outcomes in high-risk patients already taking statin therapy, have been presented. Researchers report that bococizumab had short-term benefits on lowering cholesterol levels and significantly reduced the risk of cardiovascular events by 21 percent compared to placebo among those who had baseline LDL cholesterol levels of greater than 100 mg/dL. However, the cholesterol lowering effect tended to diminish over time in some patients and bococizumab did not reduce cardiovascular event rates among those with LDL levels lower than 100 mg/dL.

The SPIRE program involved eight double-blind, placebo controlled clinical trials that were conducted simultaneously. Six lipid-lowering trials randomized 4,449 patients, who previously had a heart attack or stroke or had extremely high baseline cholesterol levels and were on statin therapy, to receive either bococizumab (150 mg subcutaneously every 2 weeks) or placebo to determine the effects on LDL levels. Two other multi-national trials randomized 27,438 patients to either bococizumab or placebo and were designed to evaluate the impact of the drug on cardiovascular outcomes, including nonfatal heart attack and stroke, hospitalization for unstable angina requiring urgent revascularization, or cardiovascular death. Almost all the patients were on statin therapy.

On November 1, 2016, the entire SPIRE clinical trials program was stopped when the sponsor, Pfizer, who manufactures bococizumab, discontinued the development of the drug when initial results from the LDL cholesterol lowering trials indicated that some trial participants had developed anti-drug antibodies, an immunologic response to the drug. Further analysis indicated that bococizumab effectively reduced LDL cholesterol levels by an average of 56 percent after 14 weeks; however, the immunologic reaction attenuated the reduction in LDL cholesterol in approximately 15 percent of those who received the drug. Data also show that there was a wide variation in the magnitude of cholesterol reduction that patients achieved with bococizumab, even among patients who did not develop the immunologic response. Bococizumab is a humanized antibody therapy that works by blocking proprotein convertase subtilisin-kexin 9 (PCSK), a protein that reduces the liver's ability to remove LDL cholesterol from the blood. "We believe that the attenuation of LDL lowering over time in the treatment group was likely due to the fact that bococizumab, a humanized antibody, led to an immunologic response in some patients. The alternative PCSK9 inhibitors evolocumab and alirocumab, which have already been approved for use, are fully human antibodies and do not have this adverse effect."

If this were a better world, the next stage in this process would be the development of one-off gene therapies for use by all adults, carried out long before old age rolls around. That is unlikely to happen any time soon within the bounds of the present regulatory environment, however. Waiting until the damage is underway and the disease process in its comparatively late stages before acting is the great failing of modern medicine and regulation of its use. So much more could be done to slow down and prevent aging by intervening sooner with these new technologies, in adults who are still young and healthy. Acting too late is always a poor strategy in comparison.

The Influence of Children on Late Life Mortality in Humans

Researchers here examine mortality data from one of the wealthier parts of the world, where more people have chosen not to have children, and thus there is a large enough data set to make useful comparisons between older people with and without children. The researchers show that having children adds a few years to life expectancy, conforming to similar past results. The demographic data offers little when it comes to support for any one possible mechanism over others, but some of the options are discussed in the paper. The primary focus is on increased support from children, financial and otherwise, once the parents have entered the frail and vulnerable final stage of aging.

It is well established that parents live longer than non-parents, but the underlying mechanisms are unclear and it is not known how the association changes over the life course. In Sweden and the other Nordic countries, there is an overall trend of increasing levels of childlessness across birth cohorts. It may therefore be valuable to improve our understanding of how childlessness is linked to health and survival chances in old age. We hypothesise that support from adult children to their ageing parents may be of importance for parental health and longevity.

However, there are of course several alternative explanations. For example, the timing and number of children could affect the mortality risk of women through biological pathways. Still, a protective effect of parenthood has been found for mothers and fathers, which may suggest that the biological mechanisms that apply to women is not the only explanation to the association, and other factors matter as well. One such factor could be various types of support from adult children to their ageing parents, such as informational, emotional and social support. In addition, parents have on average more healthful behaviours than childless individuals. It is also possible that the survival advantage of parents over non-parents is due to confounding from biological or social factors influencing the chances of having children and the risk of death. Health-related selection may be important at any phase during the life course, but it seems reasonable that the influence would not increase when parents become very old, but rather being more significant before average life expectancy (LE) as frailer individuals tend to die off. The need for social support from family members may, on the other hand, increase when parents age because ill health becomes more common with increasing age and the ability of self-care may decrease.

How the mortality advantage of parents over non-parents changes over the life span is not known. Previous studies have mainly examined associations between parity and subsequent mortality from 40 years of age up to around 60 years of age. This study closely examines the association between parenthood and longevity, with specific focus on the strength of the association in old age, and with absolute and relative measures. More specifically, we investigate; (1) the association between having a child alive in old age and the risks of death among Swedish men and women, (2) whether the association increases with age of the parent and (3) whether the association persists when stratifying for marital status (taking into account the possible confounding effect of having a partner cohabiting).

This study found an inverse association between having a child and death risks in old age, and, importantly, that the death risk differences between parents and non-parents increased with age of the parent, among men and women. Further, the differences in death risks between individuals with and without children were somewhat larger for men than for women. Our finding that the association grew stronger when parents became older is further in agreement with research suggesting that childless people face support deficits only towards the end of life. However, selective elements and alternative explanations, for example, that parents have more healthy behaviours than non-parents, are not ruled out. The association between having children and mortality persisted when stratifying for marital status, taking into account the possible confounding effect of having a partner. Two of our findings may be interpreted as working against the hypothesis about the importance of social support in older ages: the lack of a stronger mortality association for parents whose children lived fairly close, and the insignificant results for the gender of the child.

Link: http://dx.doi.org/10.1136/jech-2016-207857

Stochastic Nuclear DNA Damage in Aging

Nuclear DNA in every cell accumulates random mutational errors over time. DNA repair mechanisms are highly efficient, but nonetheless, some damage slips through. It is still an open question as to whether this damage is important over the course of the present human life span, at least beyond the matter of cancer risk, where it is well proven that more mutational damage means more cancer. Putting aside cancer for the moment, is there enough random DNA damage occurring in normal individuals to produce enough dysregulation of cellular behavior to in turn lead to meaningful levels of other forms of harm and lost function in tissues? The consensus among researchers is that this is the case, and nuclear DNA damage is listed in the noted hallmarks of aging paper, but that consensus has been challenged. This is largely a debate over theory and indirect evidence at the present time, however: is difficult to produce an animal study in which only random DNA damage is altered in degree, so as to definitively establish differences in outcome. There have been a few promising starts in that direction in the past few years, but much more work remains to be accomplished.

The cells in our bodies are constantly churning out proteins and other structures, built according to the blueprints contained in their DNA, which are crucial to supporting those cells' functions. And while in each cell most of the information contained in its DNA will be ignored, if an area of the genome important to the cell's function is damaged or develops mutations, the cell may produce misshapen proteins or simply stop functioning altogether. The effects of misshapen proteins can range from useless to actively harmful, as when neurons in a brain with Alzheimer's disease produce excessive amounts of the neurotoxic protein amyloid beta.

A few dysfunctional cells here and there don't pose much of a problem, but as more and more cells in a tissue accumulate damage over time, the health of the entire tissue or organ may be compromised. The body's normal way of dealing with such cells is to remove them through a type of programmed self-destruction called apoptosis, making way for new cells. Some cells, however, fail to die and enter a state of senescence, where they are incapable of replicating but are still left to take up space in the tissue. But especially dangerous is the case of a cell with damaged DNA that doesn't enter either apoptosis or senescence: damage drives mutation rate up each time the cell replicates, and if a mutation provides a survival advantage or switches off the cell's protective mechanisms against tumor formation, this can eventually lead to cancer. Cells that divide frequently, such as skin or lung cells, are most susceptible to this danger.

Our bodies may have evolved an impressive variety of damage repair mechanisms, but with increasing exposure to damage-causing agents in the environment and the damages caused by our own internal processes, compounded with the declining effectiveness of our protective mechanisms over time, DNA damage and mutations are bound to accumulate as we age. Some evidence suggests that caloric restriction may mitigate these effects. However, since no drugs yet exist that will prevent or repair DNA damage, all we can do at the moment is try our best to avoid harmful agents like excessive sun exposure and smoking.

Link: http://geroscience.com/genomic-instability/

Can Pregnancy Effects be Used to Argue For Changes in Cell Signaling as an Effective Approach to Treating Aging?

Over the past decade, a few research groups have provided evidence to suggest that pregnancy can enhance regeneration in the mother. The proposed mechanisms have largely involved capable stem cells from the fetus acting as a mild form of stem cell therapy when they find their way into the mother's tissues. Since then, however, parabiosis research has taken off, in which an old and a young animal have their circulatory systems joined. This has a beneficial effect on the older animal, and researchers have spent a great deal of effort investigating signal molecules in the bloodstream that differ between old and young animals. The initial focus was on finding youthful signals that might help turn back some of the detrimental changes that take place in old tissues, such as loss of regenerative capacity and decline in stem cell activity.

Perhaps unfortunately, the latest update in this line of research puts something of a damper on the idea that young signals can rejuvenate old tissues, and proposes that the effect is achieved through dilution of harmful signals or waste in the old tissues and bloodstream. Still, now that everyone is as much focused on signals as they are on stem cells, it is perhaps time to look back at the evidence for pregnancy effects. Is there anything there that might be used to argue in one direction or another when it comes to the signal environment, aging, and potential therapies? From where I stand the existing evidence looks a little sparse to be building anything atop it, but it doesn't seem like an unreasonable angle to pursue further - at least for those researchers who are focused on slowing aging through forcing change on the signaling environment. That said, there is no necessary reason why these two situations, parabiosis and pregnancy, should in the end turn out to have much in common; it could just as easily be the case that the placental barrier rules out all of the interesting exchanges that take place in parabiosis.

Why does signaling change in old tissues? Those who see aging as an accumulation of molecular damage would say it is a consequence of increased levels of damage. Cells react to their environment, and it is unfortunately the case that some of those reactions go on to cause further harm. See, for example, cells becoming senescent. There is another viewpoint, that of programmed aging, which considers signaling changes a primary cause of aging, and altered cellular behavior then in turn leads to damage. After some years of reading around that area of theory, I still think its proponents have a tough hill to climb in order to make that case. Fortunately, the development of working rejuvenation theories will settle the right and wrong of things more rapidly than the slow battles over theory; practical efforts will come to an answer in the next ten to fifteen years, I'd say. Therapies based on damage repair and therapies based on alteration of signaling are both imminent; one approach will work far better than the other, and that will be that.

Molecular and Cellular Interactions between Mother and Fetus - Pregnancy as a Rejuvenating Factor

Prevention or even reversal of aging have become topics of numerous studies. The discovery of rejuvenating factors, if they exist and are of chemical nature, would become a breaking point in solving many problems in gerontology. Scientists periodically report a discovery of such factors; however, careful examination of their data and technical details of these studies raise doubts if the discovered factors indeed possess rejuvenating properties. In particular, when the circulatory systems of two animals of different ages are connected in a heterochronic parabiotic model, the older partner undergoes rejuvenation. Some recent studies aimed to identify the chemical factor that enters the older organism from the younger one suggested that this rejuvenating factor is GDF11, a differentiation growth factor that circulates in the common blood stream of parabiotic partners. However, more detailed studies failed to unambiguously confirm that GDF11 is responsible for the rejuvenating effect.

The rejuvenating effect of pregnancy remains a subject for discussion. We find it promising to view pregnancy as a parabiotic system in which organisms of different age (young fetus and mature mother) are functionally connected and exchange factors that affect both, in either positive or negative manner. Pregnancy is a great burden for the maternal organism and carries a risk of numerous complications. Hence, for many years, both clinical medicine and academic research have concentrated mostly on negative effects of pregnancy on the mother's health. However, recent studies have shown that pregnancy might have positive effects on the physiological state of many organs and on maternal longevity in general, especially in the absence of pregnancy-accompanying complications. Some studies even discussed the "rejuvenating" effect of pregnancy on the maternal organism.

The regenerative capacity of liver (estimated from the rate of liver regeneration after removal of 2/3 of its volume) in 10-12-month-old mice was four times lower than in young (3-month-old) animals. However, when old mice were in the third trimester of pregnancy, their rate of liver regeneration after hepatectomy was like that in young animals: in both young non-pregnant mice and aged pregnant mice, liver regenerated to its initial volume ~2 days after the surgery, while in old non-pregnant animals, liver volume remained less than 50% of the original one. Another common object for studying regeneration and its decline with age is a skeletal muscle. The regeneration index in 20-month-old mice was almost 10 times lower than in 3-month-old mice. The effects of pregnancy on skeletal muscles were like those observed in liver: pregnancy enhanced two-fold the regeneration of muscles in both aged (10-month-old) and young animals. The number of satellite cells (muscle stem cells) did not differ between the groups, which indicates that deterioration of the regenerative functions was not due to the exhaustion of the pool of these cells. The decline in the regenerative capacity of muscle tissue with aging is believed to be related to changes in regulation, in particular, to inactivation of the Notch signaling pathway. Pregnancy reverses these changes in aged animals and restores the activity of this pathway to the levels typical for young individuals.

The rejuvenating effect of pregnancy might be explained by the donation of fetal cells capable to differentiate. The regenerative properties of stem cells are well known, and therapeutic effects of stem cells injection after brain, liver, or kidney damage have been well described. Some fetal cells enter the maternal circulation and tissues - a phenomenon known as microchimerism. Fetal cells could be found in the mother's blood and tissues several decades after pregnancy. At present, there is no consensus on the mechanisms that would explain the effects of microchimeric cells on the maternal organism. Two main possibilities are discussed: the first one is regulatory interactions, and the second is direct differentiation of microchimeric cells into a type of cells required for the mother's regeneration. In the first case, a limited number of fetal cells act as coordinators of the regenerative process. For example, fetal cells are believed to regulate inflammatory response by downregulating TGF-β biosynthesis and by directing maternal regeneration toward scar-less fetal-like wound healing. A direct contribution of microchimeric multipotent cells to regeneration has been demonstrated in a damaged heart model. Fetal cells actively migrated into the damaged area of the mother's heart, where they differentiated into fully functional cardiomyocytes that contracted synchronously with surrounding cells. In the absence of damage, the number of fetal cells in the heart was 20-fold less.

A major question remains: what exactly is the contribution of each of the factors to the rejuvenating effect of pregnancy on the maternal organism? The answers to this question will allow to develop clinical approaches for protection of pregnant women and health improvement in the human population in general.

Trials of Autophagy Enhancement to Treat Parkinson's Disease

Researchers are planning trials of a repurposed drug in order to test the effectiveness of enhanced autophagy to treat Parkinson's disease, a condition characterized by loss of the small population of dopaminergenic neurons in the brain. Autophagy is a cellular housekeeping method, and the various genes associated with Parkinson's suggest that the underlying disease mechanism is made worse by inadequate clearance of damaged mitochondria in neurons. Beyond Parkinson's disease, methods of producing increased autophagy are of general interest to those who would like to slow the aging process. Greater levels of autophagy are observed in many of the interventions demonstrated to modestly slow aging in laboratory species, but despite that there has been so far little progress in moving towards clinical therapies based on enhanced autophagy. We should probably expect only marginal results from this particular trial, but it will hopefully help to pave the way for future efforts that do more to boost autophagy in a targeted, deliberate way.

Scientists are hoping that a single drug can treat two devastating brain diseases: Parkinson's and Alzheimer's. The drug is nilotinib, which is approved to treat a form of leukemia. In late 2015, researchers found that small doses of the drug appeared to help a handful of people with Parkinson's disease and a related form of dementia. They'd tried the unlikely treatment because they knew nilotinib triggered cells to get rid of faulty components - including the ones associated with several brain diseases. Results of that preliminary study generated a lot of excitement, but many researchers were cautious. "It was such a small trial, there was no placebo control and it really wasn't designed to assess efficacy." So the original researchers are launching two larger and more rigorous trials of nilotinib, both designed with input from the Food and Drug Administration. One of the trials will enroll 75 patients with Parkinson's disease, the other will enroll 42 patients with Alzheimer's.

Nilotinib seems to work by eliminating toxic proteins that build up in the brains of people with Parkinson's and Alzheimer's. The drug activates a mechanism in brain cells that acts like a sort of garbage disposal. "Our drug goes into the cells to turn on that garbage disposal mechanism. And if we're able to degrade these proteins, we could potentially stop the progression of this disorder." The primary goal of the studies is to learn whether this powerful cancer drug is safe enough for patients with brain diseases. But the new studies should also provide better evidence about whether the drug really works. There's good reason for patients with Parkinson's, Alzheimer's and other neurodegenerative diseases to be optimistic these days. Drugs like nilotinib are coming along because years of research have provided a much better understanding of how these conditions damage the brain. "Now we're in the payoff phase."

Link: http://www.npr.org/sections/health-shots/2017/03/15/520170960/cancer-drug-that-might-slow-parkinson-s-alzheimer-s-headed-for-bigger-tests

RNA Interference as a Treatment for Transthyretin Amyloidosis

In this paper, the authors discuss RNA interference (RNAi) as the basis for therapies to treat transthyretin amyloidosis. In this condition, as in other forms of amyloidosis, solid deposits of misfolded or otherwise damaged proteins known as amyloid accumulate with age, causing various forms of dysfunction in tissues. In the case of transthyretin amyloid, these solid aggregates contribute to heart failure and other cardiovascular conditions, and are thought to be involved in a range of other, less immediately pressing age-related conditions. Studies of supercentenarians suggest that transthyretin amyloidosis leading to heart failure is the predominant cause of death in that population. Any comprehensive toolkit of rejuvenation therapies must include a way to clear amyloids, and thus remove their contribution to aging and age-related disease.

Transthyretin (TTR) is a transport protein that is primarily expressed in the liver. Its primary function is to transport Vitamin A (retinol) through its interaction with the retinol binding protein. Although the majority of newly synthesized TTR protein folds and functions properly, TTR protein misfolding can occur. TTR misfolding is exacerbated by destabilizing mutation and proteolysis and, if left uncorrected, misfolded TTR has a propensity to form pathologic amyloid fibrils. TTR-mediated amyloidosis (ATTR amyloidosis) is a progressive, systemic and ultimately fatal disease resulting from the damage caused by the deposition of insoluble TTR fibrils. TTR-containing amyloid fibrils can deposit in peripheral and central nervous systems, the gastrointestinal tract, eye, kidney and/or the heart. In contrast to hereditary ATTR amyloidosis, wild-type ATTR amyloidosis results from the misfolding of wild-type TTR protein with deposition occurring predominantly in the heart. Clinical presentation of wild-type ATTR amyloidosis, which includes carpal tunnel syndrome and cardiomyopathy, typically occurs much later in life relative to the hereditary forms, and likely reflects the fact that wild-type TTR is less prone to misfolding than other, mutated variants present in the hereditary form of the condition.

Although disease manifestation varies across the different forms of ATTR amyloidosis, the common feature of these diseases is the misfolding of TTR protein that ultimately results in amyloid formation and deposition. As such, mitigation of TTR amyloid deposition is crucial to the development of any successful therapeutic treatment for all forms of ATTR amyloidosis. Tetramer stabilizers are a class of small molecule therapies currently under development and even approved in certain geographic locales for the treatment of ATTR amyloidosis. These modalities aim to limit TTR aggregation by binding and stabilizing the properly folded tetramer, thereby decreasing the concentration of aggregation-prone species. To date, data from clinical trials suggests that this approach can slow the rate of ATTR amyloidosis progression. Regardless, there is still a need for effective treatments for ATTR amyloidosis.

RNA interference (RNAi) is a naturally occurring biological process by which small interfering RNA (siRNA) can direct sequence-specific degradation of mRNA, leading to inhibition of synthesis of the corresponding protein. Recent advances in the efficient and specific delivery of siRNA to the liver have paved the way for development of RNAi-based therapeutics for disease targets expressed in the liver. As such, an RNAi therapeutic strategy is well-suited to the treatment of ATTR amyloidosis. Specifically, the therapeutic hypothesis behind this strategy predicts that silencing TTR gene expression will reduce the total amount of TTR protein, both folded and misfolded, that becomes a substrate for amyloid fiber formation, thereby reducing tissue burden and the consequences thereof. Given the vast majority of pathogenic protein in ATTR amyloidosis originates in the liver, liver specific gene silencing enabled by current delivery technologies should result in nearly complete reduction of systemic TTR levels. Finally, given the ability to silence all known disease causing TTR variants, including wild-type, an RNAi therapy may be not only an effective approach for the treatment of ATTR amyloidosis but also more generally applicable.

siRNA formulations targeting TTR resulted in robust knockdown of hepatic TTR mRNA and serum protein in transgenic mice. Further, RNAi-mediated knockdown of hepatic TTR inhibited TTR protein deposition and promoted the regression of existing TTR deposits in pathologically relevant tissues. Finally, the extent of regression of TTR tissue deposits correlated with the extent of reduction in serum TTR exposure. Together, these data suggest that RNAi-mediated knockdown of hepatic TTR expression, by virtue of significantly reducing the systemic concentration of the precursor to the protein aggregate, can prevent the formation of new deposits and thereby allow an otherwise overwhelmed endogenous repair process to reverse the consequences of protein misfolding. Further, while maximal protein knockdown would be ideal, the data suggests that lower levels of knockdown also have potential to result in clinical benefit.

Link: http://dx.doi.org/10.3109/13506129.2016.1160882

Failure of Mitophagy and Mitochondrial Function in Kidney Disease

We modern humans are comparatively lightly affected when it comes to kidney failure as an age-related cause of death; it ranks fairly low in the list. We are primarily killed by cardiovascular issues and cancer. In some other species, such as domestic cats, kidney failure is a leading cause of mortality, and near all older individuals are significantly impacted by the consequences of declining kidney function whether or not it is the final cause of death. Still, a comparatively low toll for humans is no great comfort to the many who suffer, especially since there is little in the way of medical technology available at present that can address the causes of kidney failure in any meaningful way. Treatments are compensatory or palliative, attempts to slow down progression only. This may start to change soon given the advent of methods to clear senescent cells from aged tissues, as senescent cells contribute to age-related fibrosis, a dysfunction of regenerative processes in which forms of scar tissue are created in place of functional tissue. Fibrosis impacts many organs, but is notably important in age-related kidney disease. Thus we might hope that removal of senescent cells will product benefits for patients - human and feline.

In past years, researchers have considered that failure of mitochondrial function might feature as a cause of age-related kidney disease. There are arguments to be made for this conclusion, but as ever it is challenging to put the many attributes and changes observed in aged tissues and organs into a definitive order of cause and effect. Aging involves changes in near every aspect of an enormously complex and still incompletely mapped set of interdependent systems. Mitochondria are the power plants of the cell, responsible for producing chemical energy stores, among many other duties. Should they fail, cells cannot function correctly. In the SENS rejuvenation research program, damage to mitochondrial DNA in a minority of cells is implicated as a significant root cause of aging. More general and widespread mitochondrial decline may also occur for other reasons, however, such as changes in the cellular signaling environment that take place in old tissues, reactions to higher levels of molecular damage and metabolic wastes of various sorts.

In the research noted below, the authors argue for kidney disease to be caused by mitochondrial decline, which is in turn caused by an age-related failure of cellular quality control processes. Mitophagy is the name given to a collection of mechanisms responsible for removing damaged and malfunctioning mitochondria before they can cause further harm. If mitophagy declines in efficiency, then cells will become stressed and malfunction as damage builds up in the population of mitochondria. Again, where this fits in the chain of cause and consequence - that starts with the molecular damage listed in the SENS vision for rejuvenation therapies - is something of an open question. Cells communicate in many ways, and that communication reflects the state of aging in a tissue. Tracing these changes back to their root causes is very challenging; research groups can spend years proving a single step in the lengthy chain. Since there is an established list of root causes, it is probably much more efficient to build repair therapies for those root causes and see what happens as a result.

Mitochondria Play a Significant Role in Age-Associated Kidney Disease

Researchers have published findings that may provide a new approach to preventing kidney injury after ischemia. "We've shown that it's possible to prevent kidney damage by its preliminary 'training' with short periods of ischemia (blocking of blood supply). However, our main discovery is the fact that this mechanism is disabled in old animals and, as a result, a kidney becomes unprotected. It is an extremely important problem as the major part of clinical cases of renal failure occurs in aged patients. To afford the protection of their kidneys would be a great success for medicine."

In the current study, scientists developed assays that compared data from young and old rats. The scientists revealed that a considerable number of mitochondria in older rats had a lower transmembrane potential - inevitably leading to cell death. Since kidney cells cannot proliferate, their death becomes irreplaceable, leading to increasing symptoms of renal injury. This scenario leads to the kidneys being unable to fulfill their main function of removing products of metabolism from the organism, many of which are quite toxic. The researchers suggest that's why such "bad" mitochondria should be removed in the process of quality control. In a young kidney, quality control depends on the transmembrane potential of mitochondria. When the potential drops below the critical value for a long time, a mitochondrion gets a "black label" in the form of a special protein - PINK-1. Such a labeled mitochondrion undergoes a process of self-destruction (autophagy) and is destroyed within the cellular organelles called lysosomes. In cells of old kidneys, this process is not only broken, with low-potential damaged mitochondria not being destroyed - they actually increase in number.

"There is the following process: we block blood supply of the kidney (namely, we deprive it of oxygen and substrates), and under these conditions, the weakest mitochondria in cells lose their potential and are immediately removed by the quality control system. As a result, the 'renewal', or just 'purges', of the mitochondrion population takes place, and only the healthy ones survive. That's why in young rats and the case of severe kidney ischemia, mitochondria can cope with the damage and they survive. And what happens in old rats? We do kidney preconditioning, mitochondria lose their potential, but they aren't removed as the clean-up system operates poorly. As a result of such training, 'bad' mitochondria are only accumulated in an old cell, and in the case of kidney ischemia everything gets even worse. This project opens a prospect for renal failure treatment. Moreover, mechanisms that we discovered are quite universal, so it's obvious that they are also applicable not only to kidney ischemia but also to other renal pathologies."

The age-associated loss of ischemic preconditioning in the kidney is accompanied by mitochondrial dysfunction, increased protein acetylation and decreased autophagy

In young rats, ischemic preconditioning (IPC), which consists of 4 cycles of ischemia and reperfusion alleviated kidney injury caused by 40-min ischemia. However,old rats lost their ability to protect the ischemic kidney by IPC. A similar aged phenotype was demonstrated in 6-month-old OXYS rats having signs of premature aging. In the kidney of old and OXYS rats, the levels of acetylated nuclear proteins were higher than in young rats, however, unlike in young rats, acetylation levels in old and OXYS rats were further increased after IPC.

In contrast to Wistar rats, age-matched OXYS demonstrated no increase in lysosome abundance and LC3 content in the kidney after ischemia/reperfusion. The kidney LC3 levels were also lower in OXYS, even under basal conditions, and mitochondrial PINK1 and ubiquitin levels were higher, suggesting impaired mitophagy. The kidney mitochondria from old rats contained a population with diminished membrane potential and this fraction was expanded by IPC. Apparently, oxidative changes with aging result in the appearance of malfunctioning renal mitochondria due to a low efficiency of autophagy. Elevated protein acetylation might be a hallmark of aging which is associated with a decreased autophagy, accumulation of dysfunctional mitochondria, and loss of protection against ischemia by IPC.

Prototyping a Basis for the Next Generation of Retinal Prostheses

Current approaches to prosthetic sight involve connecting an grid of electrodes implanted in the retina to an external camera. The electrodes stimulate the production of glowing phosphenes, a crude visual representation of what the camera sees. It is simple and in no way real sight, but a great improvement over being completely blind. Researchers here present work on the next generation of technology for artificial substitutes to replace natural vision, removing the camera and shifting towards more miniaturized electronics:

Researchers have developed a new type of retinal prosthesis that brings research a step closer to restoring the ability of neurons in the retina to respond to light. The new prosthesis relies on two groundbreaking technologies. One consists of arrays of silicon nanowires that simultaneously sense light and electrically stimulate the retina accordingly. The nanowires give the prosthesis higher resolution than anything achieved by other devices - closer to the dense spacing of photoreceptors in the human retina. The other breakthrough is a wireless device that can transmit power and data to the nanowires over the same wireless link at record speed and energy efficiency. One of the main differences between the researchers' prototype and existing retinal prostheses is that the new system does not require a vision sensor outside of the eye to capture a visual scene and then transform it into alternating signals to sequentially stimulate retinal neurons. Instead, the silicon nanowires mimic the retina's light-sensing cones and rods to directly stimulate retinal cells. Nanowires are bundled into a grid of electrodes, directly activated by light and powered by a single wireless electrical signal.

The power provided to the nanowires from the single wireless electrical signal gives the light-activated electrodes their high sensitivity while also controlling the timing of stimulation. Power is delivered from outside the body to the implant through an inductive powering telemetry system. The device is highly energy efficient because it minimizes energy losses in wireless power and data transmission and in the stimulation process, recycling electrostatic energy circulating within the inductive resonant tank, and between capacitance on the electrodes and the resonant tank. Up to 90 percent of the energy transmitted is actually delivered and used for stimulation, which means less RF wireless power emitting radiation in the transmission, and less heating of the surrounding tissue from dissipated power.

For proof-of-concept, the researchers inserted the wirelessly powered nanowire array beneath a transgenic rat retina with rhodopsin P23H knock-in retinal degeneration. The degenerated retina interfaced in vitro with a microelectrode array for recording extracellular neural action potentials (electrical "spikes" from neural activity). The bipolar neurons fired action potentials preferentially when the prosthesis was exposed to a combination of light and electrical potential - and were silent when either light or electrical bias was absent, confirming the light-activated and voltage-controlled responsivity of the nanowire array.

Link: http://jacobsschool.ucsd.edu/news/news_releases/release.sfe?id=2150

An Interview with Kelsey Moody of Ichor Therapeutics

The Life Extension Advocacy Foundation here interviews Kelsey Moody of Ichor Therapeutics, a company working on clinical translation of the SENS rejuvenation research approach to clearing one of the forms of persistent metabolic waste that causes aging and age-related disease. In this case, it is a type of waste product that is generated in the energetic cells of the retina; as it accumulates, it leads to macular degeneration and progressive blindness:

New medical technologies need bold researchers to make the leap from the laboratory table to hospitals and clinics where they can improve or even save lives. Kelsey Moody is one such researcher. Currently research into age-related diseases takes up huge amounts of funding, however very few of these approaches aim to treat the root causes - the processes of aging - and this is why they are not successful. Moody's focus in the past few years has been developing an effective treatment for age-related macular degeneration (AMD), a leading cause of vision loss among people over 50. The experimental treatment he's working on, called LYSOCLEAR, is currently being tested for validity at Ichor Therapeutics, a startup Moody founded in 2013. LYSOCLEAR is based on the LysoSENS approach advocated for by the SENS Research Foundation, where Moody worked as an academic coordinator first in 2008-2010 and as a research scientist in 2012.

How did you learn about the SENS approach?

I first came across SENS during an online review on regenerative medicine, and this initiated my interest in the study human aging. At the time, I had no formal training in science. However, Aubrey de Grey's approach made sense to me at face value, so I purchased his book, Ending Aging, to study it further. After completing the book, I felt I did not have sufficient knowledge to know whether or not his ideas were worthy of serious pursuit, but I was intrigued. I added a major in biochemistry, and reasoned to myself that I would commit to the study of aging until such a time as it was clear to me that such a pursuit was not feasible or a worthwhile use of my time and resources. Now a decade later, I have graduate level training in research, business, and medicine. While the conversation has become much more sophisticated, the original plan holds true. I have not reached a point where I believe SENS is unworthy of serious study. I have focused my company on translational research because I believe this is the area where we can have the greatest impact and where the largest deficits exist among the various longevity organizations, both nonprofit and commercial.

How easy (or difficult) would it be to adapt LYSOCLEAR to target different types of waste products in lysosomes of different tissues?

The idea of LYSOCLEAR is based on enzyme replacement therapy, which has already been used extensively in a clinical setting for the treatment of lysosomal storage diseases. In principle, the concept of "upgrading lysosomes" can be extended to numerous diseases of aging. The challenge is almost always in identifying ways to efficiently and specifically target the payload to its destination. This is somewhat easier when your target cells are well studied and express receptors known to facilitate efficient targeting, such as monocytes or (in our case) retinal pigmented epithelial cells. It is a harder technical problem for other tissue types. Broadly though, I am optimistic that this approach can be repurposed for other diseases, either by our team or others. Atherosclerosis immediately comes to mind, and SENS Research Foundation has funded research to identify enzymes capable of degrading plaque components, such as 7-ketocholesterol.

What are the main obstacles you have met at the early stage of your project?

The recurring challenge I see in the aging space is that the overwhelming majority of "anti-aging" researchers have little to no formal scientific training or wet lab experience, (and it shows), or are basic scientists. Virtually none have translational experience - that is, experience moving benchtop discoveries into a path towards commercialization. Conversely, the translational scientists I have interacted with over the years are almost transactional, and seem to be lacking the creativity and imagination of how new technologies could be applied to solve complex medical problems. So most of the people with ideas cannot execute, and most of the people who can execute lack vision. We try to address this issue as a company by having one foot firmly in the fringe, and the other firmly in the mainstream. For example, about half of our staff are futurists with a passion for anti-aging and SENS, but we balance that with experienced pharmaceutical professionals who keep us grounded and focused on actionable discoveries and a legitimate translational strategy. Likewise, all of our drug development programs include a far reaching "moonshot" opportunity, but also a highly conservative disease indication.

Link: http://www.leafscience.org/kelsey-moody-bringing-innovation-from-the-lab-to-the-clinic/

An Update on the Use of Gene Therapies to Convert Retinal Cells

A few years back, researchers reported on a novel approach to treating the degenerative blindness of retinitis pigmentosa, an inherited condition in which the rod photoreceptor cells responsible for low-light and peripheral vision become progressively more dysfunctional, eventually leading to the death of other retinal cells. The researchers found that tinkering with levels of Nrl in retinal tissues can make rod cells transform into something more like the cone cells responsible for color vision. In normal development of retinal photoreceptor cells, those with a lot of Nrl become rods, while those with less become cones, but as demonstrated by this team, adult photoreceptors can be coerced into taking on the character or one or the other. While this isn't as good as fixing the underlying problem that causes rod cell dysfunction, it so far appears to be a potentially beneficial approach.

This is far from the only situation in the human body in which some form of conversion of adult cells might be helpful as a palliative or compensatory treatment, in absence of a true cure that addresses root causes. There are many examples of specialist cell populations impacted by aging or disease, arising from a common progenitor and thus closely related to surrounding cells. Dopaminergenic neurons, islet cells, and so on through a long list of cell types. I don't think that researchers should be starting out with this sort of approach as the end goal of their work medicine - that end goal should be to fix the underlying cause of the problem and thus effect a complete cure. But if it becomes feasible along the way, then why not?

Today I noticed a recent update on this line of research, now moved to CRISPR-based gene therapy in mice. Given the advent of CRISPR and the great reduction in the cost and difficulty of gene therapies, I have to wonder why there isn't more of a thrust towards treating the genetic cause of this condition. While the number of specific mutations thought to relate to the condition is quite large and varied - it isn't a nice, neat single gene inherited disease - it is no longer enormously costly and challenging to deliver correct versions of multiple genes to just the retina. In many ways retinal conditions are as close to an ideal testing ground for gene therapies as you are likely to find in the human body, given the relative isolation of the eye from other tissues, and the distinctive differences in those tissues that enable accurate targeting via a number of methods. Still, people more familiar than I with the costs have decided that a more general and compensatory approach makes sense.

CRISPR-Based Therapy Prevents Retinal Degeneration

Retinitis pigmentosa, which affects around one in 4,000 people, causes retinal degeneration that eventually leads to blindness. The inherited disorder has been mapped to more than 60 genes (and more than 3,000 mutations), presenting a challenge for researchers working toward a gene therapy. The results of this latest study suggest that a broader, gene-editing-based therapeutic approach could be used to target many of the genetic defects underlying retinitis pigmentosa. "This combination of CRISPR technology with an adeno-associated virus vector, a system tried and true for delivering genetic information to the retina, may represent the first step in a global treatment approach for rod-mediated degenerative disease."

Researchers designed a CRISPR single guide RNA (sgRNA) to target a retinal transcription factor, Neural retina leucine zipper (Nrl), which specifies rod cell fate during retinal development and maintains rod cells within the mature retina. The team delivered the Nrl-targeted sgRNA and the Cas9 endonuclease directly to the retina of mice on two separate adeno-associated virus (AAV) vectors. The advantage of an AAV vector is the ability to maintain long-term gene expression in non-dividing cells, such as those of the retina.

Retinitis pigmentosa causes gradual cell death - first of rod cells, responsible for night vision, followed by the more scarce cone cells, which enable color and daylight vision. Rod cells also provide structural and nutritional support to cone cells. Researchers showed that targeting Nrl could preserve the functions of cone cells in mice. Using a Cre-based recombination system, the team found that eliminating Nrl could partially convert rod cells into cone-like cells, preventing their deaths as well as the secondary cone cell death seen in retinitis pigmentosa. "The idea is that we do not turn rods into real cone cells, but for the rod cells to gain some cone feature so that they will resist the mutation effects that cause them to eventually die."

Because the Cre-recombination approach is not readily translatable into humans, researchers looked to the CRISPR system instead. The team first injected the retinas of 2-week-old wild-type mice with the experimental therapy vectors, then observed the mice for three to four months. The researchers saw reduced Nrl expression in the animals that received the therapy compared to mice injected with control vectors. At six weeks after injection, the treated animals' rod cells had downregulated rod genes and upregulated cone genes. The treatment did not result in any deleterious effect on cone cells, the researchers reported.

Nrl knockdown by AAV-delivered CRISPR/Cas9 prevents retinal degeneration in mice

In retinitis pigmentosa, loss of cone photoreceptors leads to blindness, and preservation of cone function is a major therapeutic goal. However, cone loss is thought to occur as a secondary event resulting from degeneration of rod photoreceptors. Here we report a genome editing approach in which adeno-associated virus (AAV)-mediated CRISPR/Cas9 delivery to postmitotic photoreceptors is used to target the Nrl gene, encoding for Neural retina-specific leucine zipper protein, a rod fate determinant during photoreceptor development.

Following Nrl disruption, rods gain partial features of cones and present with improved survival in the presence of mutations in rod-specific genes, consequently preventing secondary cone degeneration. In three different mouse models of retinal degeneration, the treatment substantially improves rod survival and preserves cone function. Our data suggest that CRISPR/Cas9-mediated NRL disruption in rods may be a promising treatment option for patients with retinitis pigmentosa.

Evidence for RNA Quality Control to be Among the Determinants of Longevity

Cellular quality control mechanisms such as autophagy are observed to be influential in determining natural variations in longevity. Increased autophagy, meaning that cells are working harder to recycle damaged structures and proteins, is a prominent feature of many of the interventions shown to modestly slow aging in laboratory species over the past twenty years. As a further example, autophagy appears to be required for the enhanced health and longevity produced by the practice of calorie restriction. There are other forms of quality control process beyond autophagy, however, and here researchers provide evidence to suggest that those focused on RNA molecules are also important:

DNA, RNA, and proteins carry the genetic instructions within all known living organisms. Existing research has collectively shown that organisms with long lifespans tend to have more stringent DNA and protein quality control. In other words, deterioration of DNA and protein quality control is centrally correlated with aging and age-related diseases. However, the role of the RNA quality control in aging remained almost unexplored.

Researchers have now shown that RNA quality control affects aging. The research team concentrated on a specific RNA quality control mechanism called nonsense-mediated mRNA decay (NMD), a key pathway which degrades both abnormal as well as some normal RNAs. The team has successfully shown that NMD is crucial for longevity in the roundworm called C. elegans, a popularly used animal for aging research. They first discovered that NMD activity decreases during aging. The team then discovered that enhanced NMD underlies the longevity of famous C. elegans strains called daf-2 mutants, which have reduced insulin hormone signaling.

Since the main role of NMD is degradation of its target messenger RNAs (mRNAs), the team focused on mRNAs that were downregulated in daf-2 mutants. Their research showed substantially decreased levels of a gene yars-2, an NMD target, are at least partially responsible for long lifespan in daf-2 mutants. In other words, research data collectively suggest that NMD-mediated RNA quality control is critical for longevity in C. elegans. The researchers anticipate that the discovery of the causal relationship between RNA quality control and longevity will play a significant role in shedding light on the mechanisms behind aging and eventually contribute to curing and even preventing age-related diseases.

Link: https://www.eurekalert.org/pub_releases/2017-03/puos-ral030917.php

DrugAge Database Announced

To add to the existing set of online databases relevant to aging research at senescence.info, the DrugAge database was recently announced. This contains a list of interventions that modestly slow aging in various species, along with degree of life extension obtained and references. You might compare this effort with the similar geroprotectors database. The databases are an interesting resource, but it is worth noting that from the perspective of the SENS rejuvenation research programs next to none of this data is all that relevant to the future of human healthy life extension. None of the various compounds so far shown to slow aging in other species should be expected to produce gains in humans that are significantly greater than can be obtained by lifestyle choices such as exercise and calorie restriction. To do better than that requires targeted repair of the molecular damage that causes aging, not merely slowing down the accumulation of that damage a little.

Scientists have announced a database of lifespan-extending drugs and compounds called DrugAge. The database has 418 compounds, curated from studies spanning 27 different model organisms including yeast, worms, flies and mice. It is the largest such database in the world at this time. Significantly, the study found that the majority of age-related pathways have not yet been targeted pharmacologically, and that the pharmacological modulation of aging has by and large focused upon a small subset of currently-known age-related pathways. This suggests that there is still plenty of scope for the discovery of new lifespan-extending and healthspan-extending compounds.

DrugAge is the latest of a number of valuable resources freely available on the Human Aging Genomic Resources (HAGR) website. Other resources available through HAGR include GenAge (a database of age and longevity-related genes in humans and model organisms), AnAge (a database on ageing, longevity records and life-history featuring over 4000 species), GenDR (a database of genes associated with the life extending effects of dietary restriction), and LongevityMap (a database of over 2000 human genes and genetic variations associated with longevity). The database is freely available to the public, and is searchable according to compound name, species and effect on lifespan. The data can be presented as both tables and interactive charts. Functional enrichment analysis of the targets of the database's compounds was performed using drug-gene interaction data, which revealed a modest but statistically significant correlation between the cellular targets of the database's compounds and known age-related genes.

"DrugAge represents a landmark resource for use in the biogerontology community. It is the largest database of lifespan-extending compounds compiled to date, and will surely come to be recognized as an extremely valuable resource for biogerontologists. Analysis performed using the database has already revealed interesting trends, including a modest but statistically significant overlap between lifespan-extending drugs and known age-related genes, a strong correlation between average/median lifespan changes and maximum lifespan changes, a strong correlation between the lifespan-extending effects of compounds between males and females, and perhaps most significantly that most known age-related pathways have yet to be targeted pharmacologically. More broadly, an understanding of the comparative effects of geroprotectors upon the lifespan of a variety of different model organisms is important both for basic research into the biology of ageing, demonstration of lifespan plasticity via modulation of a variety of distinct biomolecular targets as proof to regulators that healthspan extension is a viable paradigm for disease treatment and prevention, and for the eventual clinical translation of potential geroprotectors."

Link: https://www.eurekalert.org/pub_releases/2017-03/brf-bdo031017.php

A Potentially Useful New Finding in the Biochemistry of Amyloid-β

The research quoted below is illustrative of a great deal of investigation into Alzheimer's disease and related amyloid biochemistry. There is a vast depth of detail remaining to be explored, even in areas thought to be comparatively well-mapped. While much of that exploration is business as usual, leading to expected destinations and anticipated confirmations, there is always the chance of upheaval, as might be the case here. Alzheimer's disease, like many neurodegenerative conditions, is characterized by the aggregation of solid deposits of misfolded or otherwise altered proteins in brain tissue: amyloid-β and phosphorylated tau. Once established, these deposits generate a complicated halo of surrounding biochemistry that is harmful to brain cells and their activities. In fact, pretty much everything to do with Alzheimer's disease is ferociously complex and nowhere near as well understood as researchers would like it to be.

Most efforts in Alzheimer's disease are presently directed towards ways to safely remove amyloid-β, with programs aiming to remove tau also underway. Removal has the advantage of needing less progress towards complete understanding of the biochemistry of the aged, diseased brain. Unfortunately even this shortcut has proven to be far more challenging than hoped. The past decade is littered with failed efforts to remove amyloid in the immunotherapy space, for example. Only very recently has success of any sort been demonstrated in human patients. The lack of tangible progress in amyloid clearance has spurred a great deal of exploration in the field, among researchers who believe that failure indicates not unexpected difficulty but that amyloid isn't the right target. There are dozens of newer theories on Alzheimer's disease floating around with varying degrees of support in the research community. So far this hasn't made much of a dent in the primacy of amyloid clearance efforts, but the clock is clearly ticking when it comes to the balance of funding and interest.

As is the case for many new discoveries in Alzheimer's biochemistry, the researchers use this one to suggest a different direction for the development of practical therapies. Here, the intent would be to replicate work from a related field and stabilize a precursor to amyloid, in theory preventing it taking the next step that produces the excess amyloid-β found in diseased brains. This isn't completely new in Alzheimer's disease research; inhibition of amyloid creation has been suggested as an approach at other stages along the road to amyloid formation. It isn't clear that there is any better evidence for effectiveness to date than there is for amyloid clearance, however. From a high-level perspective, if amyloid is the problem, then periodic removal should be a better class of therapy than continual suppression. This is only true if it can be made to work at all, of course.

Never before seen images of early stage Alzheimer's disease

It is a long-held belief in the scientific community that the amyloid-β plaques appear almost instantaneously. New infrared spectroscopy images, however, revealed something entirely different. The researchers could now see structural, molecular changes in the brain. "No one has used this method to look at Alzheimer's development before. The images tell us that the progression is slower than we thought and that there are steps in the development of Alzheimer's disease that we know little about. This, of course, sparked our curiosity." What was happening at this previously unknown phase? The results revealed that the amyloid-β did not appear as a single peptide, a widely held belief in the field, but as a unit of four peptides sticking together, a tetramer.

This breakthrough offers a new hypothesis to the cause of the disease. The abnormal separation of these four peptides could be the start of the amyloid-β aggregation that later turns into plaques. "This is very, very exciting. In another amyloid disease, transthyretin amyloidosis, the breaking up of the tetramer has been identified as key in disease development. For this disease, there is already a drug in the clinic that stabilizes the tetramers, consequently slowing down disease progression. We hope that stabilizing amyloid-β in a similar fashion may be the way forward in developing future therapies." The discovery could therefore alter the direction of therapy development for the disease. The aim of most clinical trials today is to eliminate plaques. Researchers will now try to understand the interaction patterns of amyloid-β preceding the aggregation process. Finding the antidote to whatever breaks the amyloid-β protein apart could open doors towards a major shift in­ the development of therapies for Alzheimer's disease.

Pre-plaque conformational changes in Alzheimer's disease-linked Aβ and APP

Reducing levels of the aggregation-prone amyloid-β (Aβ) peptide that accumulates in the brain with Alzheimer's disease (AD) has been a major target of experimental therapies. An alternative approach may be to stabilize the physiological conformation of Aβ. To date, the physiological state of Aβ in brain remains unclear, since the available methods used to process brain tissue for determination of Aβ aggregate conformation can in themselves alter the structure and/or composition of the aggregates.

Here, using synchrotron-based Fourier transform infrared micro-spectroscopy, non-denaturing gel electrophoresis and conformational specific antibodies we show that the physiological conformations of Aβ and amyloid precursor protein (APP) in the brains of transgenic mouse models of AD are altered before formation of amyloid plaques. Furthermore, focal Aβ aggregates in brain that precede amyloid plaque formation localize to synaptic terminals. These changes in the states of Aβ and APP that occur prior to plaque formation may provide novel targets for AD therapy.

Evidence for Senescent Cells to Promote Vascular Calcification

The progressive stiffening of blood vessels is an important proximate cause of age-related hypertension and cardiovascular disease. One cause of this stiffening is a process of calcification, deposition of calcium into the tissues of blood vessel walls. Recent evidence shows that this process is caused by changes in cellular behavior, which opens up a range of potential targets for therapy and prevention. Here, researchers further demonstrate that the activities of senescent cells are probably involved in this picture. This is good news if validated, as targeted clearance of senescent cells as an approach to the treatment of aging is already heading towards the clinic, under active development at a number of companies.

Vascular calcification is an undervalued risk factor for the appearance of cardiovascular disease (CVD). Regarded as a surrogate marker for atherosclerosis, a condition that frequently precedes coronary events, calcification is commonly seen in the vasculature of elderly subjects, and in middle-aged subjects with premature vascular disease associated to chronic kidney disease. Hitherto, vascular calcification was thought to be a consequence of simple, physical mineral deposition in the vessel walls. New evidence, however, has revealed a highly regulated cellular response to be involved, and that calcification is the result of an imbalance between the inhibitors and inducers of calcium (Ca) deposition.

Microvesicles (MVs) - also named microparticles - are a subset of extracellular vesicles. Recent studies have shown that MVs produced by smooth muscle cells, can carry Ca as well as molecules that act as calcification nucleation sites. They may therefore also be involved in initiating vascular calcification. Endothelial senescence is known to be involved in the initiation of certain CVDs such as atherosclerosis and hypertension; the MVs produced by senescent endothelial cells (ECs) might therefore play an important role in their onset. Previous studies by our group have shown that microparticles produced by ECs in response to inflammatory stimuli, promote a calcifying response in vascular smooth muscle cells. The aim of the present study was to determine: 1) whether MVs produced by senescent, cultured ECs, plus those found in the plasma of elderly subjects, promote calcification in human aortic smooth muscle cells (HASMC), and 2) to determine which contents of such MVs might be involved.

The present results suggest that the MVs circulating in the plasma of elderly subjects contribute towards the calcification of vascular smooth muscle cells. In addition, those obtained for the in vitro-generated human umbilical vein endothelial cells (HUVEC) MVs strongly support the idea that calcification associated with aging is triggered by the MVs produced by senescent ECs. Certainly, the senescent HUVEC MVs contained increased amounts of Ca and bone-associated proteins. Compared to the younger subjects, the plasma of the elderly subjects contained a larger number of MVs in general, and of EC-produced MVs in particular. Only the MVs from the plasma of elderly subjects, and from senescent HUVEC, promoted the calcification of HASMC. It was very difficult to isolate sufficient bona fide EC-derived MVs from the plasma in order to confirm their having a role in vascular calcification. However, more than sufficient such MVs were isolated from senescent HUVEC.

The present results suggest that, with age, the number of MVs in the plasma increases, promoting vascular calcification. These MVs are likely produced by senescent ECs. Clinical studies are required to determine whether the number of calcifying MVs correlates with vascular calcification in elderly patients, and in those with premature vascular disease. The results also suggest that MVs could be used as markers of vascular calcification; their detection might be used to identify patients at risk of CVD and/or follow the clinical course of their disease. They also suggest that MVs might offer a therapeutic target for the control of vascular calcification and associated CVD.

Link: http://dx.doi.org/10.18632/aging.101191

Hypotension Evidence Supports Views of Blood Supply as Important in Dementia

The evidence presented here is supportive of views on neurodegeneration that place an emphasis on blood supply to the brain. Certainly, the aging of the cardiovascular system is strongly implicated in some forms of dementia, but not always necessarily because of a lessening supply of oxygen and nutrients. The more common picture is of small amounts of damage caused by tiny blood vessel ruptures that add up over time, but the brain is an energetic organ; it is very possible that declining supply from the circulatory system is a contributing factor.

Middle-aged people who experience temporary blood pressure drops that often cause dizziness upon standing up may be at an increased risk of developing cognitive decline and dementia 20 years later. Findings suggest that these temporary episodes - known as orthostatic hypotension - may cause lasting damage, possibly because they reduce needed blood flow to the brain. Previous research has suggested a connection between orthostatic hypotension and cognitive decline in older people, but this appears to be the first to look at long-term associations. "Even though these episodes are fleeting, they may have impacts that are long lasting. We found that those people who suffered from orthostatic hypotension in middle age were 40 percent more likely to develop dementia than those who did not. It's a significant finding and we need to better understand just what is happening."

For the study, the researchers analyzed data from the Atherosclerosis Risk in Communities (ARIC) cohort, a study of 15,792 residents in four communities in the United States, who were between the ages of 45 and 64 when the study began in 1987. For this study, they focused on the 11,503 participants at visit one who had no history of coronary heart disease or stroke. After 20 minutes lying down, researchers took the participants' blood pressure upon standing. Orthostatic hypotension was defined as a drop of 20 mmHg or more in systolic blood pressure or 10 mmHg or more in diastolic blood pressure. Roughly six percent of participants, or 703 people, met the definition. These participants, who were on average 54 years old upon enrolling in the study, continued to be followed over the next 20 or more years. People with orthostatic hypotension at the first visit were 40 percent more likely to develop dementia than those who did not have it. They had 15 percent more cognitive decline.

It is not possible to tease out for certain whether the orthostatic hypotension was an indicator of some other underlying disease or whether the drop in blood pressure itself is the cause, though it is likely that the reduction in blood flow to the brain, however temporary, could have lasting consequences. It also wasn't clear, she says, whether these participants had repeated problems with orthostatic hypotension over many years or whether they had just a brief episode of orthostatic hypotension at the original enrollment visit, as patients were not retested over time.

Link: http://www.jhsph.edu/news/news-releases/2017/rapid-blood-pressure-drops-in-middle-age-linked-to-dementia-in-old-age.html

Researchers Report on More New Senolytic Drug Candidates

Now that clearing senescent cells as a therapy for aging finally has meaningful support in the research community, there is far more funding available to turn the wheels of the standard drug discovery and evaluation process. Researchers are in search of senolytic drugs, those that can kill senescent cells without harming normal cells. The process starts at first with an evaluation of the performance of each molecule in the standard compound libraries in cell cultures, in search of molecules that preferentially kill senescent cells. This can be automated to a fair degree, especially when the desired result is as black and white as destroying one distinctive class of cell. It is very similar to the sort of cancer drug screening that the research community has a great deal of experience in carrying out. At scale, this might cost a few dollars per molecule screened these days. In fact, the existing candidates for senolytic drugs have largely emerged from the cancer drug candidate databases, and were tested for their effects on cancer for some years without noticing their strong effects on senescent cells - it wasn't in the list of items to evaluate at the time.

Given the starting point of a few promising compounds, preferably already tried in animals and humans, and thus with decent pharmacology data, researchers then branch out to examine other chemically similar compounds. It is usually the case that a better version with greater primary effects and lesser side-effects can be established one way or another. The level of work to achieve that end varies greatly, however, ranging from finding another well-characterized small molecule drug candidate in the archives to the researchers having to carry out all of the work to model and synthesize a novel molecule and prove it to be effective. It is usually the case that researchers and developers are far more willing to push ahead with a suboptimal compound that is already fairly well tested than to work with a less well explored but potentially better compound. Nonetheless, in theory the competition in the system weeds out worse drugs in favor of better drugs, though that process may never seem as efficient in practice or as fast as we'd like it to be. Personally, I'd like to see more funding going towards the sort of programmable gene therapy pioneered by Oisin Biotechnologies, a better approach than mining cancer chemotherapy drugs in search of those with side-effects that are minimal enough for patients to accept.

Then it is on to animal studies, starting companies, and human trials, the standard process for moving forward with the development of new medicine. Many candidates will turn out to be not so useful in human medicine, others will pass all the way through. Insofar as senolytic drug discovery goes, all of the groundwork has already taken place for a number of cancer drug candidates that can promote apoptosis in senescent cells, such as navitoclax and dasatinib, some of which are being carried forward into clinical trials by UNITY Biotechnology. In animal studies, these appear to remove on the order of 10-50% of senescent cells in a single course of treatment, varying widely by tissue type. The research community isn't resting on its laurels, however, and is turning up new candidates on a fairly regular basis at the moment, such as piperlongumine. The paper below offers another few candidates for consideration, though I would say that they are less interesting in and of themselves at this stage, but rather as an indication that we should expect the list of potential drugs to expand quite rapidly in the next few years, and hopefully the quality of the best candidates along with it.

New agents that target senescent cells: the flavone, fisetin, and the BCL-XL inhibitors, A1331852 and A1155463

Senescent cells accumulate in numerous tissues with aging and at sites of pathogenesis of multiple chronic diseases. Small numbers of senescent cells can cause extensive local and systemic dysfunction due to their pro-inflammatory senescence-associated secretory phenotype (SASP). For example, transplanting only 200,000 senescent ear chondroblasts or preadipocytes around knee joints induces osteoarthritis in mice, while injecting similar numbers of non-senescent cells does not. Clearing senescent cells by activating a drug-inducible "suicide" gene in progeroid or naturally-aged mice alleviates a range of age- and disease-related phenotypes, including sarcopenia, frailty, cataracts, adipose tissue dysfunction, insulin resistance, and vascular hyporeactivity.

To decrease the burden of senescent cells in non-genetically-modified individuals, we used a hypothesis-driven approach to identify senolytic compounds, which preferentially induce apoptosis in senescent rather than normal cells. Our approach was based on the observation that senescent cells are resistant to apoptosis. This suggested that senescent cells either have reduced engagement of pro-apoptotic pathways that serve to protect them from their own pro-apoptotic SASP or they have up-regulated pro-survival pathways. We demonstrated the latter to be the case and identified senescence-associated pro-survival pathways based on expression profiling of senescent vs. non-senescent cells. We confirmed the requirement of these pathways for survival of senescent but not non-senescent cells by RNA interference. These pathways included pro-survival networks related to PI3K / AKT, p53 / p21 / serpins, dependence receptor / tyrosine kinases, and BCL-2 / BCL-XL, among others.

We tested drugs that target these pro-survival pathways. We initially reported that the dependence receptor/ tyrosine kinase inhibitor, dasatinib (D) and the flavonoid, quercetin (Q), are senolytic in vitro and in vivo. D and Q induced apoptosis in senescent primary human preadipocytes and HUVECs, respectively. Combining D+Q broadened the range of senescent cells targeted, and, in some instances, proved synergistic in some types of senescent cells. D+Q alleviated cardiovascular, frailty-related, osteoporotic, neurological, radiation-induced, and other phenotypes and disorders in chronologically aged, progeroid, and high fat-fed atherosclerosis-prone mice, consistent with our observations in mice from which senescent cells had been removed by inducing the suicide gene in transgenic INK-ATTAC mice. Expanding upon our findings with Q, we tested if the related flavonoid fisetin is senolytic. Fisetin is widely available as a nutritional supplement and has a highly favorable side-effect profile.

Based on our earlier hypothesis-driven identification of senolytic drugs and identification of the BCL-2 pro-survival pathway as one of the "Achilles' heels" of senescent cells, we and others simultaneously reported that the BCL-2 / BCL-W / BCL-XL inhibitor, navitoclax (ABT263; N), is senolytic. Like D and Q, N is senescent cell type-specific, being effective in inducing apoptosis in HUVECs but not human preadipocytes. We also found that the related BCL-2 family inhibitor, TW-37, is not senolytic. TW-37, unlike N, does not target BCL-XL. Others confirmed that N targets senescent cells, but Bcl-2 family inhibitors that do not target BCL-XL are not senolytic. We therefore tested if the relatively specific BCL-XL inhibitors, A1331852 and A1155463, are senolytic. Unlike N, these agents do not target BCL-2. Consequently, A1331852 or A1155463 may cause less BCL-2-induced neutrophil toxicity, a serious side-effect of N.

We found that fisetin and the BCL-XL inhibitors, A1331852 and A1155463, are senolytic in vitro, inducing apoptosis in senescent, but not non-senescent HUVECs. This adds three new agents to the emerging repertoire of senolytics reported since early 2015, which currently includes D, Q, N, and piperlongumine. Fisetin has a plasma terminal half-life of just over 3 hours in mice. It alleviates dysfunction in animal models of chronic disease, including diabetic kidney disease and acute kidney injury, attributes consistent with those expected from a senolytic agent. Here we demonstrate that fisetin is indeed senolytic in senescent HUVECs, but not in senescent IMR-90 cells or human preadipocytes. A1331852 and A1155463 are senolytic in HUVECs and IMR-90 cells but not primary human preadipocytes. We noted that these drugs increased cellular ATP levels significantly in senescent human preadipocytes, but not HUVECs, through an as yet unknown mechanism.

We predict many more senolytic drugs will appear at an accelerating pace over the next few years. Initially, most are likely to be based on re-purposed drugs or natural products. Increasingly, new senolytics will likely be derived using medicinal chemical approaches based on optimizing properties of the repurposed agents. Consistent with this, it appears that small changes in the senolytic drugs already discovered can interfere with senolytic activity, such as in the case of D vs. imatinib, with the latter not being senolytic, or N vs. the closely-related agent, TW-37. Conversely, we speculate that small structural changes to repurposed senolytic drugs could enhance senolytic activity, with increases in the percent and range of types of senescent cells eliminated, as well as better stability, bioavailability, and side-effect profiles.

A Recent Example of Progress in the Quality of Bone Tissue Engineering

The state of the art in tissue engineering generally involves some form of biodegradable gel scaffolding material, a supply of patient-matched cells to populate that scaffold, and the delivery of a mix of proteins to induce growth and steer cells towards other desired behaviors. This effort to regrow sections of the skull is an example of the type:

A team of researchers repaired a hole in a mouse's skull by regrowing "quality bone," a breakthrough that could drastically improve the care of people who suffer severe trauma to the skull or face. The work was a resounding success, showing that a potent combination of technologies was able to regenerate the skull bone with supporting blood vessels in just the discrete area needed without developing scar tissue - and more rapidly than with previous methods. Injuries or defects in the skull or facial bones are very challenging to treat, often requiring the surgeon to graft bone from the patient's pelvis, ribs, or elsewhere. But if all goes well with this new approach, it may make painful bone grafting obsolete.

In the experiment, the researchers harvested skull cells from the mouse and engineered them to produce a potent protein to promote bone growth. They then used a hydrogel, which acted like a temporary scaffolding, to deliver and contain these cells to the affected area. It was the combination of all three technologies that proved so successful. Using calvaria or skull cells from the subject meant the body didn't reject those cells. The protein, BMP9, has been shown to promote bone cell growth more rapidly than other types of BMPs. Importantly, BMP9 also appeared to improve the creation of blood vessels in the area. Being able to safely deliver skull cells that are capable of rapidly regrowing bone in the affected site, in vivo as opposed to using them to grow bone in the laboratory, which would take a very long time, promises a therapy that might be more surgeon friendly, and not too complicated to scale up for the patients.

The scaffolding is a material based on citric acid and called PPCN-g, is a liquid that when warmed to body temperature becomes a gel-like elastic material. "When applied, the liquid, which contains cells capable of producing bone, will conform to the shape of the bone defect to make a perfect fit. It then stays in place as a gel, localizing the cells to the site for the duration of the repair. As the bone regrows, the PPCN-g is reabsorbed by the body. What we found is that these cells make natural-looking bone in the presence of the PPCN-g. The new bone is very similar to normal bone in that location. A reconstruction procedure will be a lot easier when you can harvest a few cells, make them produce the BMP9 protein, mix them in the PPCN-g solution, and apply it to the bone defect site to jump-start the new bone growth process where you want it."

Link: http://www.mccormick.northwestern.edu/news/articles/2017/03/new-material-regrows-bone.html

GABA and Retinal Regeneration in Zebrafish

Researchers here investigate the mechanisms by which zebrafish can regenerate their retina, a form of regrowth that does not occur in mammals. This is one part of much broader efforts to understand whether or not the basis for the proficient regeneration of organs observed in zebrafish also exists in mammals, part of a shared evolutionary heritage from common ancestors, but suppressed in mammalian species. There is at this point no real consensus on the odds, nor enough information to estimate how hard it might be to safely coerce mammalian tissues into zebrafish-like regenerative prowess.

If you were a fish and your retina was damaged, it could repair itself and your vision would be restored in a few weeks. Sadly, human eyes don't have this beneficial ability. However, new research into retinal regeneration in zebrafish has identified a signal that appears to trigger the self-repair process. And, if confirmed by follow-up studies, the discovery raises the possibility that human retinas can also be induced to regenerate, naturally repairing damage caused by degenerative retinal diseases and injury, including age-related macular degeneration and retinitis pigmentosa. "The prevailing belief has been that the regeneration process in fish retinas is triggered by secreted growth factors, but our results indicate that the neurotransmitter GABA might initiate the process instead. All the regeneration models assume that a retina must be seriously damaged before regeneration takes place, but our studies indicate that GABA can induce this process even in undamaged retinas."

It turns out that the structure of the retinas of fish and mammals are basically the same. Although the retina is very thin - less than 0.5 millimeters thick - it contains three layers of nerve cells: photoreceptors that detect the light, horizontal cells that integrate the signals from the photoreceptors and ganglion cells that receive the visual information and route it to the brain. In addition, the retina contains a special type of adult stem cell, called Müller glia, that span all three layers and provide mechanical support and electrical insulation. In fish retinas, they also play a key role in regeneration. When regeneration is triggered, the Müller glia dedifferentiate (regress from a specialized state to a simpler state), begin proliferating, and then differentiate into replacements for the damaged nerve cells. Müller glia are also present in mammalian retinas, but don't regenerate.

Reseachers designed a series of experiments with zebrafish which determined that high concentrations of GABA in the retina keep the Müller glia quiescent and that they begin dedifferentiating and proliferating when GABA concentrations drop. They tested their hypothesis in two ways: By blinding zebrafish and injecting them with drugs that stimulate GABA production and by injecting normal zebrafish with an enzyme that lowers the GABA levels in their eyes. When the biologists injected drugs that kept GABA concentrations in the retinas of newly blinded fish at a high level, they found that it suppressed the regeneration process. On the other hand, when they injected an enzyme that lowers GABA levels in the eyes of normal fish, they found that the Müller glia began dedifferentiating and proliferating, the first stage in the regeneration process.

"Our theory is that a drop in GABA concentration is the trigger for regeneration. It initiates a cascade of events that includes the activation of the Müller glia and the production of various growth factors that stimulate cell growth and proliferation. If we are correct, then it might be possible to stimulate human retinas to repair themselves by treating them with a GABA inhibitor. Last month a paper was published that reports GABA levels play a central role in the regeneration of pancreas cells. We now have three instances where GABA is involved in regeneration - the hippocampus, the pancreas, and the retina - so this could be an important, previously unknown role for the neurotransmitter."

Link: https://news.vanderbilt.edu/2017/03/09/fish-eyes-may-hold-key-to-regenerating-human-retinas/

Choosing to Lead an Inactive Life Means Paying the Price for that Choice

It is no great secret that, all other things being equal, people who are some combination of less fit, less active, and more overweight suffer from a greater incidence of age-related health issues and have a shorter life expectancy. They also pay a higher lifetime cost for medical treatment despite that shorter life expectancy. A century of medical studies on this topic demonstrate these points quite comprehensively. Much as some sedentary or overweight people like to hear that their choices do not have serious consequences, this is not the case - they do have serious consequences. Yes, it is harder to stay thin and active in this age of ease of transport and more calories than any individual can possibly work their way through. Yes, it is easier to postpone exercise indefinitely and eat whatever you feel like eating. Nonetheless, this is all still a matter of choice. Those thinner people you see walking around out there? Those physiques didn't happen by accident. Choose to swing the odds towards a healthier, longer future, or choose to swing the odds towards a less healthy, shorter future: it is up to you.

If this was an age of stasis, in which medicine was not advancing at a very rapid pace, one might make the nihilist's argument that we'll all end up in the same place in the end, and that it is a person's free choice to consume for pleasure now at the cost of suffering later. Kicking the can down the line is a human specialty, after all. But we do live in an age of rapid progress in biotechnology, in which practical, working rejuvenation therapies will emerge over the decades ahead. In this environment, a few years here and a few years there do matter. Postponing the decline of old age to the best reasonable extent possible with the limited but freely available and reliable tools of today, meaning exercise and calorie restriction, might make a very large difference in the end - the difference between living to benefit significantly from rejuvenation treatments, or missing out on that era. Consider the odds. Perhaps science will advance enough to rescue you from any additional harms you do to yourself above and beyond those inflicted by aging, but why roll the dice if you don't have to?

For today's glance at the scientific world, look below to see a brace of references to recent studies on activity levels and age-related disease. They recapitulate thin slices of what is already well known about exercise, fat tissue, and health, but there seems to be an endless font of funding for the increasingly details quantification of exercise and its effects. Why this must be the case, whilst researchers working on genuinely new medical science find it ever a struggle to obtain grants, is a question with no satisfactory answer. If we lived in a better world, there would be a great deal more funding for the new and the experimental aimed at cures, when considered in comparison to the work of finely cataloging the present state of health and operation of the human machine absent those cures.

Physical inactivity and sedentary behaviors are associated with cardiometabolic risk factors

Previous studies of healthy adults and persons with diabetes have demonstrated that physical activity - particularly activities with moderate-high intensity - and daily sedentary behaviors, such as watching television, have a significant effect on cardiometabolic health. Nevertheless, these observations have never been explored in older adults at high cardiovascular risk, a typically sedentary and physically inactive population that has a high risk of developing chronic diseases. Consequently, researchers implemented the PREDIMED-PLUS trial and thus address this question by evaluating different types of physical activities and sedentary behaviors in a population of 5,576 men and women with high cardiovascular risk. They have also studied the effect of replacing the time spent watching television with the same time engaging physical activities with different intensities.

The most striking results from this investigation show that increasing the time spent on physical activities with moderate-high intensity (brisk walking, climbing stairs, working in the garden or performing sports) by one hour a day was associated with a 3%-6% increase in protection against obesity, diabetes, abdominal obesity and low HDL-cholesterol. In contrast, increasing the time spent watching television by one hour a day was associated with an increased presence of these cardiometabolic risk factors. Moreover, when one hour a day of watching television was replaced by one hour a day of physical activity with moderate-high intensity, the protection against these cardiometabiloc risk factors was even greater (3%-9%) than the protection observed when each activity was evaluated separately.

Overweight, obese people risk heart disease at younger ages

In a new study, overweight and obese people tended to have slightly shorter or similar lifespans compared to people with normal body weight, whether or not they had cardiovascular diseases. But compared to people with normal BMI, lifetime risks for developing cardiovascular disease were higher in overweight and obese adults. For example, overweight middle-aged women were 32 percent more likely to develop cardiovascular disease in their lifetime compared to those of normal weight. Average years lived without cardiovascular disease were longest for people with normal BMI, while years lived with cardiovascular disease were longest for overweight and obese people.

Overweight or obese people also experienced cardiovascular disease at an earlier age than those with normal BMI. For example, among overweight middle-aged women, cardiovascular disease began 1.8 years earlier than normal weight women, and 4.3 years earlier for those who were obese. For the study, the researchers looked at cardiovascular disease data of 72,490 people, focusing on patients in middle-age, who were 55-years-old on average. Participants were healthy and free of cardiovascular disease when they enrolled in the study. The average BMI was 27.4 for men and 27.1 for women. "Our findings suggest that healthcare providers need to continue to be aware of the increased risk of earlier cardiovascular disease faced by overweight and obese people. Healthcare providers should emphasize the importance of maintaining healthy weight throughout their lives to live longer, healthier lives."

Prolonged sedentary time and physical fitness among Canadian men and women aged 60 to 69

This study examined associations between sedentary time and fitness among Canadians in their sixties. The main findings were that, after adjusting for moderate-to-vigorous physical activity (MVPA): 1) objectively measured sedentary time was inversely associated with cardiorespiratory fitness and grip strength; 2) the number of breaks in sedentary time was positively associated with cardiorespiratory fitness; 3) the percentage of sedentary time spent in bouts of at least 20 minutes was inversely associated with cardiorespiratory fitness; 4) associations between sedentary time in bouts of at least 20 minutes and breaks in sedentary time and cardiorespiratory fitness were not consistent between sexes, nor were associations between sedentary time and grip strength; and 5) self-reported sedentary time was not related to any fitness variable. The last conforms with previous work showing measured sedentary time to be more consistently related to health outcomes than are self-reported measures.Note

Earlier research indicates that sedentary time and patterns of sedentary time are associated with older adults' health and functional fitness. In the present study, the percentage of total sedentary time spent in bouts of at least 20 minutes was inversely associated with cardiorespiratory fitness, and a greater number of breaks in sedentary time was associated with better cardiorespiratory fitness. These findings are important because cardiorespiratory fitness is a strong predictor of morbidity and all-cause mortality. In 2015, it was demonstrated that non-exercising older adults with higher cardiorespiratory fitness have better vascular function and lower cardiovascular risk. It was suggested that greater amounts of non-exercise activity, such as activities of daily living, may partly explain the fitness and vascular health of some older individuals who do not engage in purposeful physical actvity. It is possible that adaptations in the vasculature, and likely other components such as muscle oxidative capacity, are stimulated by light intensity activities.

Total sedentary time was inversely related to grip strength in men and women, even after adjusting for MVPA. As well, the association between breaks in sedentary time and sit-and-reach scores was positive among men. Therefore, sedentary time may also influence musculoskeletal fitness, which is crucial for independent living and autonomy. These data demonstrate a significant relationship between directly measured sedentary time, breaks in sedentary time, and fitness among Canadians in their sixties. Given long-established associations between fitness and both health and functional autonomy for older adults, this study underscores the importance of minimizing total sedentary time and breaking up sedentary time, in addition to increasing physical activity.

Older adults who exercise regularly may lower chances for severe mobility problems

Based on the proven health benefits of exercise for older adults, a team of researchers theorized that exercise might also help adults prevent or delay disabilities that interfere with independent living. The researchers enrolled 1,635 adults between the ages of 70 and 89. All of the participants were at high-risk for becoming physically disabled. At the beginning of the study, the participants were able to walk about five city blocks (one-quarter of a mile) without assistance. The participants were split into two groups. One group was encouraged to exercise regularly. In addition to taking a daily 30-minute walk, they performed balance training and muscle strengthening exercises. The other group attended weekly workshops for 26 weeks, followed by monthly sessions. The workshops provided information about accessing the healthcare system, traveling safely, getting health screenings, and finding reliable sources for health and nutrition education. The workshop instructors also led the participants in 5- to 10-minute flexibility or stretching exercise sessions. Researchers gave all participants thorough tests for disability at the beginning of the study and then at 6, 12, 24, and 36 months after the study started. The researchers reported that people in both groups experienced about the same level of disability after the study. However, people in the exercise group experienced a lower level of severe mobility problems than did people who attended the health workshops.

Infection and Inflammation in Neurodegenerative Conditions

Increased levels of chronic inflammation accompany aging, and this drives faster progression of a range of age-related conditions, spurring greater damage and loss of function in tissues. Researchers here ask to what degree this is due to opportunistic infections and a weakened immune system rather than being caused by the more general dysfunction and overactivation of the aged immune system that would occur even absent such infections, the state known as inflammaging. Like many such investigations, this serves to emphasize the need for effective means to rejuvenate the age-damaged immune system, such as through clearing and recreating immune cell populations, restoring the thymus to youthful levels of activity, or replacing blood stem cells.

The immune system undergoes many changes with age that leaves the elderly more susceptible to infection, indeed older individuals are more vulnerable to bacterial or viral infections of the urinary or respiratory tract, with influenza-related morbidity also increased in this group. Sepsis, which is caused by severe infection, can also lead to permanent cognitive dysfunction, particularly in older individuals. Importantly, infectious burden in the elderly is associated with mini-mental state examination (MMSE) scores below 24, which indicate dementia. Unfortunately, the symptoms of infection often present atypically in this group and, as dementia patients are often unable to communicate their symptoms, diagnosis is difficult. To further complicate matters, bacterial resistance is often increased in older patients.

Individuals with Alzheimer's disease (AD) are even more vulnerable to the effects of peripheral infection. In a 10-year follow-up study, delirium (which is often caused by infection) correlated with an eightfold increase in dementia development. Furthermore, the cognitive capabilities of AD patients worsened significantly after an episode of delirium, which has been confirmed by others. Indeed poor health and viral burden have been linked with cognitive impairment and AD development in the elderly. It was found that the incidence of many infectious conditions such as pneumonia, lower respiratory tract, or urinary tract infections is higher in AD patients than healthy, age-matched controls. Previous studies have demonstrated that numerous infections over a 4-year period doubled the risk of AD development. Indeed cognitive decline has been observed just 2 or 6 months after a resolved peripheral infection, with an association between cognitive impairment and circulating proinflammatory cytokines.

The emerging evidence strongly indicates that infection has a significant role in the development of, and progression to, dementia, with a growing list of pathogens specifically associated with AD or amyloid-β deposition. This may be due in part to some of the changes that are known to occur to the immune system with age. One of the key changes in the adaptive immune system is the involution of the thymus, resulting in a dramatic decrease in the production of new T cells. With age, there is an overall decrease in naive T cells, and a corresponding increase in memory T cells. This is associated with a reduction in naive T cell diversity after the age of 65, with clonally expanded subsets of memory T cells often observed in this age group, which can occur from chronic or repeat infections. Together, this can limit the capacity of the individual to induce a sufficient immune response to new infectious challenges.

It is clear from the evidence that AD patients are more vulnerable to the effects of peripheral infection than their age-matched, healthy counterparts. Importantly, it is indisputable that many specific viral, bacterial, and fungal infections are associated with AD development, although whether these pathogens are a direct cause of dementia or instead are advantageous, infiltrating microorganisms that exacerbate the neuroinflammation already ongoing in these individuals remains to be confirmed. Importantly, the blood-brain barrier of AD patients is significantly leakier than in healthy subjects, which facilitates infiltration of peripheral immune cells and possibly these infectious pathogens. Together, this demonstrates the critical need for early detection and treatment of infections in the elderly and in those with dementia. As infectious diseases can present atypically in this group, frequent screening and vaccination are key to preventing infection-related deterioration of cognition until new therapies are established that can protect the elderly from these unnecessary insults.

Link: https://dx.doi.org/10.1186/s13195-017-0241-2

Investigating Retrotransposons in Alzheimer's Disease

A number of research groups are involved in the study of retrotransposons in the context of aging. These are genetic sequences that can copy themselves within the genome, and that activity increases with age. Linking this definitively to specific manifestations of aging is still to be accomplished, however. There are all the same challenges in making this connection as are inherent in proving that increased levels of stochastic nuclear DNA damage are a significant cause of dysfunction in aging beyond cancer risk. Correlations can be demonstrated, but evidence for causation is elusive. In the speculative research noted here, scientists investigate the behavior of retrotransposons in connection with the development of Alzheimer's disease:

The dominant idea guiding Alzheimer's research for 25 years has been that the disease results from the abnormal buildup of hard, waxy amyloid plaques in the parts of the brain that control memory. But drug trials using anti-amyloid drugs have failed, leading some researchers to theorize that amyloid buildup is a byproduct of the disease, not a cause. This study builds on an alternative hypothesis. First proposed in 2004, the "mitochondrial cascade hypothesis" posits that changes in the cellular powerhouses, not amyloid buildup, are what cause neurons to die. Like most human cells, neurons rely on mitochondria to stay healthy. But unlike other cells, most neurons stop dividing after birth, so they can't be replaced if they're damaged. In Alzheimer's patients, the thinking goes, the mitochondria in neurons stop working properly. As a result they are unable to generate as much energy for neurons, which starve and die with no way to replenish them. But how mitochondria in neurons decline with age is largely unknown.

Most mitochondrial proteins are encoded by genes in the cell nucleus before reaching their final destination in mitochondria. In 2009, researchers identified a non-coding region in a gene called TOMM40 that varies in length. The team found that the length of this region can help predict a person's Alzheimer's risk and age of onset. The researchers wondered if the length variation in TOMM40 was only part of the equation. They analyzed the corresponding gene region in gray mouse lemurs, teacup-sized primates known to develop amyloid brain plaques and other Alzheimer's-like symptoms with age. They found that in mouse lemurs alone, but not other lemur species, the region is loaded with short stretches of DNA called Alus. Found only in primates, Alus belong to a family of retrotransposons or "jumping genes," which copy and paste themselves in new spots in the genome. If the Alu copies present within the TOMM40 gene somehow interfere with the path from gene to protein, the researchers reasoned, they could help explain why mitochondria in nerve cells stop working.

When the researchers looked across the human genome, they found that Alus were more likely to be lurking in and around genes essential to mitochondria than in other protein-coding genes. Alus are normally held in check by clusters of atoms called methyl groups that stick to the outside of the DNA and shut off their ability to jump or turn genes on or off. But in aging brains, DNA methylation patterns change, which allows some Alu copies to re-awaken. The TOMM40 gene encodes a barrel-shaped protein in the outer membrane of mitochondria that forms a channel for molecules - including the precursor to amyloid - to enter. Researchers used 3D modeling to show that Alu insertions within the TOMM40 gene could make the channel protein it encodes fold into the wrong shape, causing the mitochondria's import machinery to clog and stop working. The TOMM40 gene is one example, but if Alus disrupt other mitochondrial genes, the same basic mechanism could help explain the initial stages of other neurodegenerative diseases too, including Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis (ALS).

Link: https://today.duke.edu/2017/03/jumping-genes-suspected-alzheimers

Old Stem Cells are Most Likely Still Useful Stem Cells

There is an intriguing amount of evidence to suggest that the stem cells remaining in the tissues of old people are still quite capable. If removed from the old cellular environments, many aspects of their behavior become similar to those of the same type of stem cell taken from a younger individual, at least in some reports. There is a greater level of accumulated cellular damage in old stem cells, but much of the evidence suggests that this does not provide as great a contribution to degenerative aging as do diminished numbers and diminished activity. Stem cell activity in the old is much declined from youthful levels, as I'm sure regular readers know. This activity is necessary for the support of tissues, supplying replacement somatic cells and generating signals that adjust cell behavior. The loss of regenerative capacity and consequent slow failure of tissue function an important part of the processes of aging.

As to whether the principal problem is loss of stem cells or that the stem cells are present but become perpetually quiescent, the evidence is varied. The situation is probably different for different stem cell populations, and to muddy the waters further, these are most likely overlapping issues. The stem cell populations react to the aging of tissues, meaning the rising level of damage and the changing signal environment that results from that damage. This reaction may be to self-renew less readily, decreasing the size of the stem cell population, or to remain quiescent and inactive for ever longer periods, decreasing the number of active stem cells at any point in time. Or both. The consensus theory on this process is that it is a part of the evolved balance between aging and cancer. As damage grows, so too does cancer risk, and stem cell decline can serve to reduce cancer risk at the cost of a slower decline into frailty and death.

Whether old stem cells are inherently dysfunctional is a question of considerable relevance to the practical development of stem cell therapies. The present direction in therapies is to use a patient's own cells, to take existing stem cells to generate more of the same for transplant, or to use those stem cells to create differentiated cells and tissues, again for transplantation. If aged stem cells are inherently dysfunctional, that would greatly limit the ability to use this class of therapies for older people, those who most need such treatments. But if, as seems to be the case, old stem cells are still capable in and of themselves, then this approach to regenerative medicine for age-related disease has a brighter future. Of course, the influence of the aged tissue environment still means that a challenging problem must be to solve to build effective regenerative therapies for the old: how to ensure that the fate of transplanted cells isn't just a repeat of what has already happened to the native cell populations? The regenerative medicine industry has to grapple with the causes and mechanisms of aging in one way or another, given that the vast majority of patients are in fact old, and the state of their aged tissues impacts cell therapy effectiveness.

Regenerative capacity of autologous stem cell transplantation in elderly: a report of biomedical outcomes

Stem cells are found not only in embryonic or fetal tissues but also in all adult tissues in relatively high numbers. These cells are committed to tissue repair throughout adult life. Although the number of cells and their capabilities decrease over time, rich stem cell niches remain such as bone marrow and adipose tissue. The observation that stem cells differentiate into several cell lineages reveals their potential for use in regenerative medicine. More importantly, stem cells harvested from adult tissue can be used for autologous transplantation and can also avoid immunological rejection. However, whether stem cells from elderly people have similar capabilities as those found in younger people is yet unknown. Some studies suggest that elderly people have fewer stem cells and that they have lost their capacity for growth and differentiation in vitro. Other evidence indicates that sufficient numbers of stem cells remain throughout adult life, providing an alternative for use in cell therapy.

Self-renewal in vitro is one of the main stem cell characteristics that occur after harvest. Healthy adult stem cells grown in vitro have a high proliferation capacity. However, stem cells from elderly subjects show less proliferation potential. Several studies have reported a decrease in the number of colony forming units in mesenchymal stem cell (MSC) cultures from donors aged ≥40 years. In vitro doubling times are longer in cells taken from elderly patients than those from younger donors and show a substantial decrease in proliferation rate. Similar observations have been reported for lipoaspirate samples obtained from adipose tissue. In vitro doubling times differ depending on donor age and are longer in those collected from older donors. The relationship between the decrease in number and functionality of stem cells could be a consequence of the loss of proper environmental signals. In addition, decreased telomere length and an increased rate of apoptosis and its signals have been reported in MSCs harvested from elderly donors. In addition, the definition of MSCs requires the presence of specific cell membrane antigens, as well as human leukocyte antigen class II. Until now, flow cytometry has been performed on MSCs from younger and elderly patients to confirm the presence or absence of these specific stem cell markers. The overall conclusions from these reports are that MSCs from elderly donors have less capability to grow.

Differential expression of stemness genes on MSCs from elderly donors may be ultimately responsible for the decline of the stem cell proliferation rate. Stemness genes characterized in bone marrow-derived stem cells from patients with amyotrophic lateral sclerosis (ALS) show decreased expression of two genes related with pluripotential for the transcription factors OCT4 and NANOG. In addition, decreased expression of trophic factors have been reported. Similar observations have been reported for adipose-derived stem cells (ADSCs) from healthy patients aged from 50 to 60 years. However, others have reported no difference in the expression of NANOG or OCT4 between MSCs isolated from the bone marrow of children and those obtained from adults. Despite these controversial reports, the general consensus supports that the expression of stemness genes is lower, but their activity is sufficient for growth and self-renewal.

Several studies have shown that healthy adult stem cells grown under specific culture conditions will differentiate into various cell lineages in vitro. The bone-forming capacity is similar in cells obtained from younger and older donors. One hypothesis proposes that the senescence-associated decrease in bone formation is due to a defect in the bone microenvironment. Chondrogenic differentiation is also controversial, as some studies have shown independent age-related responses or reduced capacity with age. Other stem cell sources, such as muscle-derived stem cells obtained from young (age 9 years) and old (age ≥60 years) humans, replicated 20- to 30-times in vitro and differentiated into different tissue lineages. These cells (satellite cells) are found in aged human skeletal muscle and are capable of regeneration. Stem cells from elderly donors do not have as much pluripotential as cells from younger donors. Nevertheless, these cells are capable of self-renewal and differentiation into osteoblasts, chondroblasts, adipocytes and other cell lineages.

Samples of pluripotent stem cells for autologous transplantation have been obtained from several tissues of differently aged donors. The most abundant and relatively accessible sources for adult stem cells are bone marrow, peripheral blood and adipose tissue. Samples from elderly people have been obtained, applied to autologous transplantation and have improved some degenerative diseases. The beneficial effects of autologous cell transplantation have been reported in patients with neurodegenerative diseases, including those performed on elderly patients. The stem cell subpopulations selected for treatment may have improved the outcomes. Several clinical trials have been performed on cardiomyopathies in patients greater than 50 years old. The most promising among those trials included infusion bone marrow-derived stem cells or MSCs from peripheral blood in patients suffering a myocardial infarction, in whom a moderate but significant improvement in left ventricular ejection volume was observed. There is no consensus about the best MSC subtype to treat ischemic heart disease. Nevertheless, all studies in this area have reported improved cardiac function after autologous MSC transplantation.

In summary, stem cells obtained from elderly patients retain pivotal membrane cell markers and have in vitro self-renewal and differentiation capabilities in adipocytes, osteoblasts and chondroblasts. In addition, stem cells from elderly patients express the transcription factors responsible for cell proliferation, such as SOX2, NANOG and OCT4. Some reports have indicated that these genes are expressed at lower levels in elderly subjects than stem cells obtained from younger donors. Nevertheless, the cells respond to induced differentiation as well as those obtained from younger donors. Several trials are currently being performed using autologous MSCs in elderly patients. Until more data are gathered indicating some beneficial effects, there is no consensus on the utility of stem cells as a gold standard treatment, but stem cells from elderly donors have similarly capabilities to growth and differentiation as younger donors.

A Mechanism by Which Inflammation Spreads in the Brain

Increased inflammation in brain tissues is an important aspect of many age-related neurodegenerative conditions, and reducing that inflammation can help matters. Some chronic inflammation results from poor lifestyle choices, such as carrying excess visceral fat tissue, but the rest results from the molecular damage of aging and disarray of the immune system, both of which we can do comparatively little about at present. Better approaches to medicine are needed. Here, researchers investigate the spread of inflammation in the aging brain, and identify a mechanism that might be sabotaged in order to reduce the impact of localized increases in inflammation. This is another of many approaches to the dysfunction of aging tissues that fails to address root causes, but might nonetheless product enough of a benefit in the short term to be considered worth development into a therapy:

Researchers have identified a new mechanism by which inflammation can spread throughout the brain after injury. This mechanism may explain the widespread and long-lasting inflammation that occurs after traumatic brain injury, and may play a role in other neurodegenerative diseases. This new understanding has the potential to transform how brain inflammation is understood, and, ultimately, how it is treated. The researchers showed that microparticles derived from brain inflammatory cells are markedly increased in both the brain and the blood following experimental traumatic brain injury (TBI). These microparticles carry pro-inflammatory factors that can activate normal immune cells, making them potentially toxic to brain neurons. Injecting such microparticles into the brains of uninjured animals creates progressive inflammation at both the injection site and eventually in more distant sites.

Chronic inflammation has been increasingly implicated in the progressive cell loss and neurological changes that occur after TBI. These inflammatory microparticles may be a key mechanism for chronic, progressive brain inflammation and may represent a new target for treating brain injury. "These results potentially provide a new conceptual framework for understanding brain inflammation and its relationship to brain cell loss and neurological deficits after head injury, and may be relevant for other neurodegenerative disorders such as Alzheimer disease in which neuroinflammation may also play a role. The idea that brain inflammation can trigger more inflammation at a distance through the release of microparticles may offer novel treatment targets for a number of important brain diseases."

The researchers studied mice, and found that in animals who had a traumatic brain injury, levels of microparticles in the blood were much higher. Because each kind of cell in the body has a distinct fingerprint, the researchers could track exactly where the microparticles came from. The microparticles they looked at in this study are released from cells known as microglia, immune cells that are common in the brain. After an injury, these cells often go into overdrive in an attempt to fix the injury. But this outsized response can change protective inflammatory responses to chronic destructive ones. The researchers also found that exposing the inflammatory microparticles to a compound called PEG-TB could neutralize them. This opens up the possibility of using that compound or others to treat TBI, and perhaps even other neurodegenerative diseases.

Link: https://www.eurekalert.org/pub_releases/2017-03/uoms-rih030717.php

Quantifying the Effects of Exercise on Mitochondria and Other Cellular Structures

Exercise is good for you, the evidence is overwhelmingly in support of that conclusion, and most people should probably undertake more activity than they do. One of the interesting outcomes produced by advances in biotechnology is an increased ability to quantify the results of different types of exercise where they differ. Personally, I'm a firm believer in the idea that optimization of diet, activity, and other lifestyle choices beyond the 80/20 point is largely a waste of time at present, as you'll never know whether or not your attempts at optimization are actually producing further improvements in life expectancy. That may not be true in the future, however, given much more knowledge and better and more widely available tools. That said, in the future we'll have also have access to rejuvenation and enhancement therapies that will produce such profound effects on health as to make optimization of everyday health practices such as exercise pointless for other reasons.

It's oft-repeated but true: exercise keeps you healthy. It boosts your immune system, keeps the mind sharp, helps you sleep, maintains your muscle tone, and extends your healthy lifespan. Researchers have long suspected that the benefits of exercise extend down to the cellular level, but know relatively little about which exercises help cells rebuild key organelles that deteriorate with aging. A study has found that exercise - in particular high-intensity interval training in aerobic exercises such as biking and walking - caused cells to make more proteins for their energy-producing mitochondria and their protein-building ribosomes. "Based on everything we know, there's no substitute for these exercise programs when it comes to delaying the aging process. These things we are seeing cannot be done by any medicine."

The study enrolled 36 men and 36 women from two age groups - "young" volunteers who were 18-30 years old and "older" volunteers who were 65-80 years old - into three different exercise programs: one where the volunteers did high-intensity interval biking, one where the volunteers did strength training with weights, and one that combined strength training and interval training. Then the researchers took biopsies from the volunteers' thigh muscles and compared the molecular makeup of their muscle cells to samples from sedentary volunteers. The researchers also assessed the volunteers' amount of lean muscle mass and insulin sensitivity. They found that while strength training was effective at building muscle mass, high-intensity interval training yielded the biggest benefits at the cellular level. The younger volunteers in the interval training group saw a 49% increase in mitochondrial capacity, and the older volunteers saw an even more dramatic 69% increase. Interval training also improved volunteers' insulin sensitivity. However, interval training was less effective at improving muscle strength, which typically declines with aging.

As we age, the energy-generating capacity of our cells' mitochondria slowly decreases. By comparing proteomic and RNA-sequencing data from people on different exercise programs, the researchers found evidence that exercise encourages the cell to make more RNA copies of genes coding for mitochondrial proteins and proteins responsible for muscle growth. Exercise also appeared to boost the ribosomes' ability to build mitochondrial proteins. The most impressive finding was the increase in muscle protein content. In some cases, the high-intensity biking regimen actually seemed to reverse the age-related decline in mitochondrial function and proteins needed for muscle building. The high-intensity biking regimen also rejuvenated the volunteers' ribosomes, which are responsible for producing our cells' protein building blocks. The researchers also found a robust increase in mitochondrial protein synthesis. Increase in protein content explains enhanced mitochondrial function and muscle hypertrophy. Exercise's ability to transform these key organelles could explain why exercise benefits our health in so many different ways.

Link: https://www.eurekalert.org/pub_releases/2017-03/cp-het030217.php

Another Example of Work on Markers of Cellular Senescence and Disruption of Signaling by Senescent Cells

A great deal of research into the phenomenon of cellular senescence is taking place these days; an explosion of effort and funding in comparison to the start of the decade, a time at which it was next to impossible to make any progress in this part of the field. The turning point was philanthropy, a gift of the necessary funds to run the first animal study that provided direct evidence for targeted removal of senescent cells to slow the aging process. For decades prior to this point, compelling indirect evidence existed for senescent cells to be a contributing cause of degenerative aging, but despite the growing advocacy of groups like Methuselah Foundation and SENS Research Foundation, it was still very hard to find that money. Now the tipping point has passed, all sorts of findings are being made, however: direct links between cellular senescence and age-related disease, findings that could have been made ten or twenty years ago were there the will and the funding at that time, albeit at greater cost and effort. This is something we should all bear in mind as we look at other areas of the SENS rejuvenation research agenda and ask why it is not progressing as rapidly as we'd like. All it takes is that one study and suddenly everyone in the research community, all the people who wouldn't give you the time of day last year, agree that you were right all along - and then forget your name in the rush to append their own to the newly growing field. Such is the way the world works. It isn't fair, it isn't efficient, but it is what it is, and we do our best to change it.

The open access paper linked below is one of many examples to illustrate two trends in the more energetic recent research of cellular senescence: firstly, to find more and better biomarkers that distinguish senescent cells from their peers, and secondly to find ways to minimize the harms done by senescent cells without destroying them. The first sounds like a great idea, as the presently established state of the art in senescent cell assays and markers is more or less the same as it was fifteen years ago - good enough for laboratory research after the old model, but not a sound basis for the clinical therapies and more discriminating research of the years ahead. It seems evident that something better is possible in this age of accelerating growth in the capabilities of biotechnology. The second course of action, on the other hand, strikes me as a tough road in comparison to the more direct approach of destroying senescent cells. That destruction seems unambiguously beneficial in mice, even when all such cells are constantly removed throughout life, via genetic engineering approaches. In human therapies, at least at the outset, removal would only occur every so often, during a treatment. The transient roles for senescent cells would continue as they were, such as in wound healing and suppression of potentially cancerous cells.

So the argument made in this paper, and elsewhere, that we should be cautious and leave senescent cells in place, doesn't seem like one with a lot of support given the evidence to date. Those researchers making it are asking for the community to give up the short path to effective therapies in exchange for a long path to worse therapies. Removal of senescent cells could be carried out quite infrequently, perhaps every few years or every decade. Suppression of senescent cells on the other hand would mean constant medication, and the struggle to safely adjust very complex cellular behavior that is still incompletely cataloged. Each form of damage and misbehavior created by the senescence-associated secretory phenotype (SASP) would have to be mapped and then drugs designed to impact it; it could take decades, even under optimistic estimates of future capabilities of the industry. Destruction of these cells, on the other hand, can be done now in the lab, and is only a few years away from the clinic. Time matters in the treatment of aging, as we don't have an infinite amount of it.

Integrin Beta 3 Regulates Cellular Senescence by Activating the TGF-β Pathway

Cellular senescence is characterized by a proliferative arrest induced to prevent the propagation of damaged cells in a tissue. This arrest is mainly driven by the activation of two important pathways, p53/p21CIP and RB/p16INK4A. The senescence program can be triggered by a number of stressors, like the activation of oncogenes, drug treatment, or deregulation of Polycomb Repressive Complex 1 (PRC1) proteins, including the polycomb protein chromobox 7 (CBX7). Although arrested, senescent cells are metabolically and transcriptionally functional, and they actively communicate with their surroundings. In fact, senescent cells secrete an array of inflammatory proteins, growth factors, and metalloproteases that collectively constitute the SASP (senescence-associated secretory phenotype). The SASP recruits the immune system in order to eliminate senescent cells and induces changes in the extracellular matrix (ECM), thus facilitating tissue homeostasis and regeneration. The presence of senescent cells has been found in vivo in preneoplastic lesions, in wound healing, during embryonic development, and in different tissues throughout aging. Interestingly, a recent study has demonstrated that p16INK4A-positive cells accumulate during aging and contribute to age-related dysfunctions in different tissues. Thus, the elimination of senescent cells reverses the aging phenotype and stimulates tissue regeneration, demonstrating that the activation of senescence is a direct cause of aging and opening avenues for targeting senescent cells as a therapy to extend healthy lifespan.

Intercellular communication is an important feature to maintain tissue homeostasis, where the activation of cellular senescence plays a crucial role. In fact, previous reports have found ECM remodeling to regulate fibrosis by activating the senescence program. Apart from inflammation and ECM remodeling, cells can communicate via the secretion of extracellular vesicles, cell-cell contact, or intercellular protein transfer. Here, we provide evidence that the integrin β3 subunit plays a role in senescence through activation of the TGF-β pathway. A great deal of information exists regarding the biological function of integrins and their regulation of the microenvironment, but relatively little is known about the transcriptional regulation of integrins themselves. We show that β3 subunit expression accelerates the onset of senescence in human primary fibroblasts, which is dependent on the activation of the p21CIP/p53 pathways. Our results also show a robust expression of β3 upon senescence activation induced by a variety of stimuli, while interference with its expression levels disrupts the senescence phenotype. Furthermore, mice lacking β3 accelerate wound-healing closure, which could be by restricting the induction of senescence.

Cellular adhesion is a key feature of senescence. In agreement with our results, several reports have found differential expression of integrins during cellular senescence activation. Analysis of published datasets show that the "cellular adhesion" pathway and integrins are differentially expressed during senescence activation. Likewise, a number of studies have found that TGF-β ligands are part of the SASP and play an important role in senescence through p21CIP regulation, in agreement with our data. The TGF-β superfamily controls numerous cellular and biological processes, such as development, regeneration, fibrosis, and cancer. Accumulating evidence indicates that a cross-talk between integrins and TGF-β exists, in particular to regulate fibrosis, wound healing, and cancer. However, even if senescence is known to regulate all these biological processes, none of these studies have reported the existence of a cross-talk between integrins and TGF-β in senescence or aging. Our data show that β3 regulates senescence by activating TGF-β via cell-autonomous and non-cell-autonomous mechanisms. The use of small molecule inhibitors, RNAi technology, and the analysis of the expression levels of various members of the TGF-β pathway authenticate a role for TGF-β during senescence induced by β3 expression.

Our data show an increase in the expression levels of β3 mRNA concomitant with an increase in different markers of senescence in tissue from old mice. Upregulation of β3 and senescence/aging markers, including TGF-β members, was further observed in fibroblasts from old human donors. This is in accordance with previous reports, which have found that p16INK4A levels correlate with chronological age in most tissues analyzed, both in mice and in humans. Interestingly, knockdown of β3 mRNA partially reversed the aging phenotype of fibroblasts derived from old human donors. However, the αvβ3 antagonist, cilengitide, could not reverse aging, suggesting that the role for β3 in this cellular system is independent of its ligand-binding activity. Our data show that cilengitide has a diverse effect on the SASP and on the senescence growth arrest. As senescent cells accumulate during aging, causing chronic inflammation, cilengitide could be a potential therapeutic route to block inflammation without affecting proliferation in aging. In summary, here, we provide evidence for the β3 subunit being a marker and regulator of senescence, and identify integrins as potential therapeutic targets to promote healthy aging.

A Demonstration in Mice of Whole Mitochondria Delivered as a Therapy

Mitochondria, the swarming power plants of the cell, become damaged and dysfunctional with age. Can this be addressed by delivering complete, whole, new mitochondria as a therapy? There have been signs in past years that cells can ingest and incorporate mitochondria from the surrounding environment, but few useful demonstrations to show whether or not this is common in living tissues. In the research here, researchers achieve that result, delivering mitochondria into tissues as a therapy, and using this approach to treat an animal model of Parkinson's disease. This neurodegenerative condition is associated with degraded mitochondrial function, especially in the dopamine-generating neurons in the brain; depletion of that cell population produces the visible symptoms of the disease.

Unfortunately it isn't clear as to whether usefulness in addressing mitochondrial dysfunction in Parkinson's will translate to usefulness in addressing the type of mitochondrial dysfunction thought to cause aging in general. The contribution to aging is based on damage to mitochondrial DNA resulting in mutant mitochondria that are both malfunctioning and capable of outcompeting the normal mitochondria present in a cell quite quickly. Delivering new, fully functional mitochondria might not do much in this situation; they would simply be outcompeted again. It still seems worth the attempt if it turns out to be comparatively easy to replicate this demonstration in mice, on the grounds that you never know in certainty until you try, but I'm not optimistic based on the current understanding of the situation. On the other hand, one potentially interesting application of mitochondrial uptake might be to provide people an upgrade from a comparatively poor mitochondrial haplotype to a comparatively better mitochondrial haplotype, as different mitochondrial genomes have different performance characteristics.

Mitochondrial dysfunction is associated with a large number of human diseases, including neurological and muscular degeneration, cardiovascular disorders, obesity, diabetes, aging and rare mitochondrial diseases. Replacement of dysfunctional mitochondria with functional exogenous mitochondria is proposed as a general principle to treat these diseases. Here we found that mitochondria isolated from human hepatoma cell could naturally enter human neuroblastoma cell line, and when the mitochondria were intravenously injected into mice, all of the mice were survived and no obvious abnormality appeared. The results of in vivo distribution suggested that the exogenous mitochondria distributed in various tissues including brain, liver, kidney, muscle and heart, which would benefit for multi-systemically mitochondrial diseases.

In normal mice, mitochondrial supplement improved their endurance by increase of energy production in forced swimming test; and in experimental Parkinson's disease (PD) model mice induced by respiratory chain inhibitor MPTP, mitochondrial replacement prevented experimental PD progress through increasing the activity of electron transport chain, decreasing reactive oxygen species level, and preventing cell apoptosis and necrosis. Since effective drugs remain elusive to date for mitochondrial diseases, the strategy of mitochondrial replacement would provide an essential and innovative approach as mitochondrial therapy.

Link: http://dx.doi.org/10.1016/j.mito.2017.02.005

A Popular Science Article on Treating Aging as a Medical Condition

The popular press, even the popular science press, generally does a terrible job of reporting on the state of longevity science. They'll pull a random set of activities, rank them all equally, whether calorie restriction, complete nonsense involving supplements, or serious efforts to achieve rejuvenation after the SENS model of damage repair, and thus fail to achieve or convey any sort of meaningful understanding of what is going on in the field. The nature of the approach taken to treating aging as a medical condition is of very great importance, and the various options currently on the table are far from equal in their potential. Most are either a waste of time and effort, or are going to produce marginal results at best. Most of the time spent on practical implementations is wasted, because it follows paths that cannot plausibly produce good results, sad to say. This article is above average, but that is a low bar to pass at the moment.

Wander down a supplement aisle at your local pharmacy or hop on the internet, and it's not hard to find products that promise to "slow the normal signs of aging" or that offer "long-term well-being at the cellular level." Humans have been trying to outsmart the inevitable for centuries. After hundreds of years of effort, there is still no miracle pill that can turn back time, despite the claims of zealous entrepreneurs. Some pseudoaging treatments over the years have been risky, capable of doing more harm than good. Others have just yielded disappointing scientific results. But there's a silver lining to the snake oil. "If there's such a big market for stuff that doesn't work, imagine how much money there would be for something that does."

Over the past few centuries, modern medicine and other innovations have doubled our life span, but these treatments have focused on curing diseases that spring up during old age, such as cancer and heart disease, rather than decoding the underlying cellular and molecular processes that make the elderly vulnerable to these afflictions in the first place. Given the financial incentive and the enormous demand, one might ponder why aging science still has not yielded clinically proven therapies to combat our decline. The short answer is that aging is mind-bogglingly complicated. Despite the challenges, there's hope for those who want to live healthier for longer. Researchers are uncovering ways to turn back time on aging cells, and several existing drugs are being reborn as antiaging candidates. And big players with deep pockets have jumped into the aging game, eager to wield genomics, big data tools, and machine-learning techniques as weapons against humanity's oldest rival.

"If you talk about increasing life span, some people say, 'Whoa, what about overpopulation? I don't want to be old for 100 years. Life span extension raises natural concerns. On the other hand, if you say, 'I don't want you to develop Alzheimer's, ever,' nobody is going to argue against that." As a result, many in the field of aging have stopped talking about extending life span, preferring to describe their goal as extending "health span," especially because age is the number one risk factor for many diseases.

One of the most promising avenues of aging research is the inroads researchers have made in understanding senescent cells. Like aging in general, senescent cells evolved to benefit young, reproductive members of the species, but they become increasingly problematic for the elderly. When you're young, senescent cells are programmed to stop dividing if they are in danger of becoming cancerous. Not only that, but senescent cells also secrete a host of molecules that, in young people, stimulate regeneration and repair. But over time, as more and more cells turn senescent, levels of these secreted molecules stop positively influencing their neighbors and begin causing inflammation. Groups of senescent cells produce such high levels of these chemicals that other, normal cells are persuaded to turn senescent. The secreted cocktail can even activate a variety of age-related pathologies, including heart disease and certain types of cancer - a disease that senescent cells evolved to thwart in the first place.

There's been a recent "gold rush" of researchers identifying therapeutic compounds that target senescent cells and can periodically deactivate them in older people. Cell-penetrating peptides, dietary flavonols, small interfering RNA, and the cancer drug dasatinib are a few of the many research routes being taken. UNITY Biotechnology aims to clear senescent cells from the kidney, eyes, arteries, and joints using a compound called navitoclax, or ABT-263, that had previously been investigated for cancer. "If chemists can come up with drugs that can kill senescent cells in humans, we think this is going to revolutionize modern medicine. No longer would you have a pill for your blood pressure and a pill for your glaucoma and a pill to stabilize your heart and a pill to improve your kidney function. You'd have a pill that would hit multiple problems that affect the elderly. It is very unlikely that these are drugs that you would have to take every day. Just when enough senescent cells had accumulated again."

Link: http://cen.acs.org/articles/95/i10/hit-snooze-button-aging.html

Searching for Similarities in the Biochemistry of Long-Lived Mammals

Portions of the aging research community study various long-lived mammals, such as naked mole-rats, bowhead whales, elephants, and Brandt's bats. In most cases research projects compare a long-lived species with another species that is similar but short lived; consider the many papers examining the differences between naked mole-rats and mice or rats, for example. Naked mole rats and mice are about the same size, but the naked mole-rats live an order of magnitude longer. The hope is that such large differences in life span should help to illuminate those areas of cellular biochemistry most important in determining the pace of aging.

At this stage in the growth of the comparative biology of aging it is still a question mark as to just how much can be done with this knowledge, once obtained. Will it be practical to port over aspects of the biology of long-lived mammals to humans any time soon? Given the lengthy, expensive, and so far largely fruitless struggles to find ways to make human biochemistry undergo the beneficial calorie restriction response without actual calorie restriction, a mere change of state in one species, I have to think that we shouldn't be holding our breath waiting for medicine based on the biochemistry of other species. Controlling the operation of metabolism to this degree has been demonstrated to be a substantial challenge given present capabilities. Progress will occur, but for now there are far more effective paths forward, such as the SENS approach of repairing our existing metabolism rather than making attempts to change its operation.

In the research linked below, researchers take the approach of looking at the genetics and biochemistry of a few different long-lived mammal species, searching for similarities between them. In theory these species are long-lived for broadly similar evolutionary reasons despite their differences, or at least the hope is that evolutionary pressures converge at similar mechanisms for longevity assurance in species in the same portion of the tree of life. This may or may not be the case, of course, but it seems sensible to try an investigation along these lines if the goal is to better understand exactly how mammalian biochemistry gives rise to such large variations in life span between species.

Adaptive sequence convergence of the tumor suppressor ADAMTS9 between small-bodied mammals displaying exceptional longevity

For several decades, it has been well recognized that there is strong correlation between lifespan and body mass, with larger species typically living longer than smaller species. There are, however, several species that violate this general rule, living much longer than expected given their small size and high metabolic rates. Of particular interest are the microbats, several species of which demonstrate longer maximum lifespans than any other mammals when controlling for body size. In addition to their exceptional longevity, microbats appear to be resistant to neoplasia and remain healthy and reproductively capable throughout the majority of their lives. Much like the microbats, the naked mole-rat lives approximately three times longer than expected given its small size, is remarkably resistant to neoplasia and displays no symptoms of aging well into its second decade.

Although once thought to be rare, there have been numerous recent studies demonstrating adaptive sequence convergence between a variety of species displaying convergent traits. These studies have highlighted genes that have been repeatedly targeted during the evolution of a given trait. For example, the evolution of echolocation in bats and toothed whales appears to be driven, in part, by common mutations. This and other evidence demonstrates that common selective pressures can drive common mutations in relevant genes.

The evolution of extreme longevity in microbats and the naked mole-rat is likely attributable to a lack of extrinsic sources of mortality in these species. Bats, being nocturnal and capable of flight, generally contend with few predators. Likewise, the naked mole-rat lives in subterranean burrows where the risk of predation is low. Several theories of aging suggest that a lack of extrinsic sources of mortality will result in selection for longer lifespan. For example, according to the antagonistic pleiotropy (AP) theory of aging, a mutation can be beneficial during development, but have late-onset deleterious effects. AP is expected to be more prevalent in species with high levels of extrinsic mortality since most individuals are unlikely to survive long after reaching sexual maturity, therefore there will be little pressure to select against the deleterious effects that manifest later in life. Also, the disposability theory of aging suggests that there exists a trade-off between growth/development and repair/maintenance. In species that contend with many predators, it should be beneficial to allocate resources to grow and develop as quickly as possible rather than to invest in repair and maintenance since longevity is already unlikely.

According to both theories, for species that contend with numerous extrinsic sources of mortality, the decline in fitness due to aging is minimal, so selection is inefficient at promoting mutations that increase longevity. However, for species that exist in relatively safe niches, like microbats and the naked mole-rat, the strength of selection to delay senescence will be much stronger, as individuals that live longer will have higher lifetime reproductive fitness. We hypothesize that the pressure to delay senescence shared by microbats and naked mole-rat may have led to convergent sequence evolution in key longevity promoting genes. The identification of genes that have undergone convergent evolution in these long-lived species would provide a better understanding of the genetics of longevity and could potentially identify therapeutic targets for cancer and other age-related illnesses. Here we tested for adaptive convergent sequence evolution between microbats and the naked mole-rat in almost 5,000 genes conserved across a wide-range of mammals. We found that A disintegrin-like and metalloprotease with thrombospondin type 1 motifs 9 (ADAMTS9) displays numerous convergent substitutions between the long-lived species that were likely driven by positive selection.

ADAMTS9 is the most widely conserved member of the ADAMTS family and has recently been reported to be a novel tumor suppressor that is downregulated in several varieties of human cancer. Intriguingly, ADAMTS9 inhibits tumor growth by blocking the mTOR pathway, which has long been known to be associated with aging. In addition to its role in tumor suppression, ADAMTS9 has also been implicated in several age-related conditions including arthritis, type 2 diabetes, macular degeneration, and menopause. Furthermore, in C. elegans the loss of GON-1, the roundworm homolog of ADAMTS9, alters lifespan and promotes dauer formation. These effects are likely due to modified insulin and insulin-like ortholog secretion and altered insulin/IGF-1 signaling, which is also known to contribute to aging.

Although it may be possible that the observed convergent changes shared by microbats and the naked mole-rat may be the product of some non-adaptive force rather than selection for increased longevity, several lines of evidence suggest otherwise. First, the convergent substitutions are distributed along the length of the coding sequence, eliminating gene conversion or alternate exon usage as possible causes. Second, the convergent topology was strongly favored when only sites with evidence of positive selection occurring on the long-lived microbat branch were considered, suggesting that the convergence was indeed driven by selection. Finally, ADAMTS9 has previously been implicated in several aging processes and age-related diseases, supporting the hypothesis that modulation of ADAMTS9 function alters lifespan. Together, this evidence suggests that ADAMTS9 has been repeatedly targeted by selection for increased longevity in microbats and the naked mole-rat.

Modest Life Extension in Yeast by Reducing Intentional DNA Damage

Double-strand breaks in nuclear DNA are one of the more severe forms of DNA damage, though not as bad as large deletions as little to no information is lost, and in a healthy and young cell even a double-strand break is quickly repaired. Interestingly, double-strand breaks can occur intentionally in the cell, a part of its normal operation, and are thus not only the result of haphazard chemical reactions. This does make age-related failure of DNA repair mechanisms a more serious matter: unrepaired double-strand breaks are harmful to cells, and a higher rate of such breaks could promote, for example, more cellular senescence, known to contribute to the aging process. You might look way back in the archives at the late Robert Bradbury's double-strand break view of aging for related thoughts on this topic. Could we get by with fewer intentional double-strand breaks, and would that somewhat slow the course of aging? Here, an initial study on this question suggests the answer is yes, at least in yeast cells, though I suspect the situation to be more complex in higher forms of life.

Researchers have demonstrated a causal relationship between reduced DNA damage and extended lifespan, identifying a cellular factor - an enzyme called topoisomerase 2, or Top2, implicated in DNA damage - that can be targeted to reduce that damage. Top2 introduces double strand breaks into DNA as part of its catalytic cycle. The breaks must then be resealed. "Every once in a while Top2 gets trapped on the DNA before it can seal the breaks. When that happens, at least in young cells, there are a number of back-up systems that recognize the breaks and repair them." However, researchers have shown that DNA damage repair systems decline as cells age, causing the unrepaired DNA breaks created by Top2 to persist. The unrepaired double strand breaks cause aging, diseases like cancer, and, ultimately, death.

"Many investigators are trying to reverse aging by boosting the backup DNA repair systems in aging cells. A simpler therapeutic approach may be to administer drugs that reduce the activity of enzymes like Top2 that cause DNA damage in the first place." A three- to five-fold reduction in Top2 activity in aging yeast cells resulted in a 20 to 30 percent increase in lifespan.

The lab would not have uncovered Top2's role if it had not first discovered LS1, an unusual Top2 poison. Unlike other Top2 poisons, which are usually highly toxic, LS1 shortens lifespan without affecting the health of young cells. When introduced into yeast cells, LS1 prevents Top2 from repairing its DNA double strand breaks. That's not a problem in young cells with healthy DNA repair systems, but deadly in older cells. However, by transiently stopping Top2 from repairing its own breaks, LS1 enhances the potency of anti-cancer drugs that themselves target Top2 in human cancer cells. For example, the chemotherapy drug doxorubicin causes cardiotoxicity when overused. However, if the potency of doxorubicin were increased by also administering LS1, the same therapeutic affects might be achieved by using less of the drug, reducing the chance of side effects, and extending the utility of these frontline cancer drugs.

Link: http://www.rochester.edu/newscenter/study-identifies-key-factor-in-dna-damage-associated-with-aging-222862/

Age-Related Failure of Autophagy Contributes to Stem Cell Decline

Researchers here provide evidence that points to declining autophagy as a cause of the faltering stem cell activity that accompanies aging. Autophagy is an important process of cellular maintenance, a part of recycling damaged structures and proteins within cells. Increased levels of autophagy are a feature of numerous methods of modestly slowing aging demonstrated in mice and other laboratory species. Unfortunately autophagy fails with age; like all systems it is impacted by the accumulation of molecular damage, and in particular in this case, by the growing amounts of metabolic waste making up lipofuscin, a mix of various compounds that mammalian biochemistry struggles to break down. Lipofuscin ends up accumulated in lysosomes, recycling systems in the cell that play an important role in autophagy, and degrades their function. If repairing this problem will not only improve the quality of cells, but also restore more youthful levels of stem cell activity, that would be a considerable victory. It is all the more reason to support the work of the SENS Research Foundation and others on ways to safely clear out the constituents of lipofuscin and thus restore lysosomal function in aged tissues.

Researchers have discovered that in addition to its normal role in cellular waste-processing, autophagy also is needed for the orderly maintenance of blood-forming hematopoietic stem cells (HSCs), the adult stem cells that give rise to red blood cells, which carry oxygen, and to platelets, which prevent bleeding, as well as the entire immune system, which fights infections and disposes of pathogens. The researchers found that autophagy keeps HSCs in check by allowing metabolically active HSCs to return to a resting, quiescent state akin to hibernation. This is the default state of adult HSCs, allowing their maintenance for a lifetime.

Failure to activate autophagy has profound impacts on the blood system, leading to the unbalanced production of certain types of blood cells. Defective autophagy also diminished the ability of HSCs to regenerate the entire blood system when they were transplanted into irradiated mice, a procedure similar to bone marrow transplantation. The researchers determined that 70 percent of HSCs from old mice were not undergoing autophagy, and these cells exhibited the dysfunctional features common among old HSCs. However, the 30 percent of old HSCs that did undergo autophagy looked and acted like HSCs from younger mice.

In a large series of experiments and analyses, the scientists compared characteristics of HSCs from old mice with those of HSCs from younger mice that had been genetically programmed so that they could not undergo autophagy. They found that loss of autophagy in young mice was sufficient to drive many of the defects that arise naturally in the blood of old mice, including changes in the cellular appearance of HSCs and a disruption in the normal proportions of the various types of blood cells, characteristics of old age. Previous research had shown that autophagy causes the formation of "sacs" within cells that can engulf and enzymatically digest molecules and even major cellular structures, including mitochondria, the cell's biochemical power plants. But in the new study, the researchers found that genetically programmed loss of autophagy resulted in the accumulation of activated mitochondria with increased oxidative metabolism that triggered chemical modifications of DNA in HSCs.

These "epigenetic" DNA modifications altered the activities of genes in a way that changed the developmental fate of HSCs. They triggered disproportionate production of certain blood cells and reduced the ability of HSCs to regenerate the entire blood system when transplanted. This result was similar to what the researchers observed in the majority of old HSCs that failed to activate autophagy. In contrast, the minority of old HSCs that still exhibited significant levels of autophagy were able to keep their mitochondria and metabolism in check, and could re-establish a healthy blood system following transplantation, similar to HSCs from young mice. However, in a hopeful sign for potential future therapies to rejuvenate blood stem cells, the researchers succeeded in restoring autophagy to old HSCs by treating them with pharmacological agents in a lab dish.

Link: https://www.ucsf.edu/news/2017/03/405951/ucsf-researchers-find-key-tired-blood-and-immune-systems

Mikhail Batin and the Open Longevity Project

The Life Extension Advocacy Foundation folk recently spoke to Mikhail Batin, long-standing advocate for radical life extension, and noted the latest venture from the Russian community, Open Longevity. In keeping with the spirit of the times, this is focused on setting up the infrastructure to run public human trials of interventions that may slow aging, on actually getting something done. That is admirable; we certainly need more of that in this era of stifling, overbearing regulation of every aspect of medical progress. I hope to see this effort succeed and grow. That said, I can't say as I think their initial choices are worth chasing: calorie restriction mimetics and a polypill approach that mixes existing drugs used to lower cardiovascular disease risk. If there were no other options, then yes, a polypill might be a surprisingly good choice, and calorie restriction is certainly better than nothing. But there are other options, and those options are far, far better. For example, it should be perfectly possible to set up open, responsible trials of some of the senescent cell clearance drug candidates such as navitoclax or piperlongumine, given that their pharmacology is well characterized already. Jailbreaking these compounds from the regulatory establishment would be a worthy exercise, assuming their effects on senescent cells in mice hold up in humans. Alas, each to their own, for better or worse.

As an aside for those readers come more recently to Fight Aging!, I should note that there is a fair-sized Russian-language longevity advocacy movement, on a par with that of the US or Europe. It reflects the strong level of support for the goal of health life extension in that part of the world, given the relative sizes of the overall populations. You might look at the Science for Life Extension Foundation as an organization that occupies an analogous position in the Russian community when compared to the Methuselah Foundation and SENS Research Foundation in the US community. Contact and collaboration between the Russian- and English-language communities has grown considerably over the past decade, which I think has as much to do with advances in automated translation as it does with the research community coming closer to clinical therapies capable of treating the causes of aging. There is certainly much more of a sense of the practical possibilities in the field these days, and that draws in ever more supporters and advocates.

As a sweeping generalization, the Russian end of the longevity science community is more in favor of programmed aging theories, and thus more in favor of tinkering with the operation of metabolism as the best way forward to slow aging or make tissues act in a more youthful fashion. This tends to involve drug discovery aimed at altering cellular behavior, such as via recreating some of the effects of calorie restriction, though some more interesting items have emerged, such as mitochondrially targeted antioxidants. It is somewhat ironic that the English-language research community is much more in favor of theories that describe aging as an accumulation of molecular damage, but the members of that community still near-entirely work on tinkering with metabolism to slow aging via drug discovery, something that their foundation of theory should decry as a marginal effort that does nothing to address the true causes of age and age-related disease. We can hope that this will change as SENS rejuvenation approaches based on damage repair, such as the newly popular efforts to remove senescent cells from aged tissues, continue to produce far more reliable and impressive results than any of the other options - and that organizations such as Open Longevity also pick up that banner to help carry it forward.

LEAF Meets Mikhail Batin

The rejuvenation research community is very diverse. Despite each of us having their favorite projects or directions of activity, the achievement of our common goal - the extended period of health and productivity - is highly dependent on this diversity. We need advocacy organizations to educate the public and fundraise actively, in order to support fundamental research. Once these fundamental studies are done, we need biotechnology startups to play their role in taking these new potential therapies through preclinical testing. Then bigger companies or venture investors need to support these startups with clinical trials in order to get promising interventions approved by regulatory authorities. Each stage is necessary to transform an idea into a treatment. Regardless of what aspect of this process a person or group works within it is always nice to meet like-minded people who are trying to find a way to achieve results sooner.

There are many drugs which are already approved to treat specific diseases, but which are also known to have the potential to address aspects of the aging process. Sadly, most have not yet been tested in healthy middle aged people in clinical trials, so we cannot be sure about their effect on the human lifespan. So, should we just wait for a research organization or pharmaceutical company to do this? Mikhail Batin, the head of Science for Life Extension Foundation, says no. Recently in the US to attend the conference The Biology of Aging: Advances in Therapeutic Approaches to Extend Healthspan, Mikhail also stopped by to visit with LEAF President Keith Comito and discuss life extension activities in Russia and Mikhail's new ambitious project - Open Longevity.

Mikhail believes there are alternative ways to organize pilot clinical trials and obtain crucial data about promising geroprotectors - information that every member of our community would benefit from. The solution is simple and elegant: members of a local community can become participants of a trial themselves, while a specialized patient organization will ensure proper procedures (study protocol development and observation, analysis of the data and preparation of a publication) are followed. This is the main goal of Russian initiative Open Longevity, started few months ago. So far, Open Longevity is planning to test a combination of statins with sartans as a pilot project, the team is open to discussion regarding the experiment design and protocol.

Open Longevity

Our task is to run clinical trials of anti-aging therapies. There are a lot of candidates for anti-aging drugs - geroprotectors. Promising results can be seen in tests on lab animals and in observational human studies. It's time to determine what intervention exactly will be best for each individual. Our plan is to channel the energy of patients to find the best one. We create the infrastructure project linking scientists, physicians and potential subjects.

Open Longevity Project has two parts: First, it's a patients organization initiating clinical trials. Patients will become not only initiators, but also the holders of the obtained data. We want to aim their energy in scientific track and to give everyone a chance to contribute in the fight against aging. Of course, this does not negate the fact that all studies will be conducted strictly under the supervision of professionals. We are talking about a public non-profit organization, and of course there will be other goals for it: fundraising and attracting other resources, lobbying and education. The more members we have, the louder will be our voice.

Second, Open Longevity is an online platform for self health monitoring. Yes, there are a lot of platforms like this. But we're special - we want to turn every patient into the researcher. Do you take medications, supplements or just experiment with your diet? We encourage everyone to pass the required tests before and after your interventions. This will give an understanding of whether it works for you or not. And will generate big data. Isn't it what's been lacking, our little programmers of neural networks?

Progress in Bioprinting of Vascular Networks

Perhaps the greatest challenge in tissue engineering, and this has been true for a decade now, is creating the necessary networks of blood vessels to support large sections of tissue. The approaches to the problem are no big secret: either print the blood vessels into the tissue structure as it is assembled, or somehow guide cells into doing that job for you. Unfortunately both paths have proven to be far more difficult than anticipated, which is one of the reasons why decellularization of donor organs has received so much attention. In that case, natural vascular network structures already exist and will be recreated much as they were when the decellularized tissue is repopulated with cells cultured from a patient sample. Still, progress towards the goal of fully vascularized engineered tissue continues, either via bioprinting or carefully steered growth, with technology demonstrations such as the one noted here emerging of late:

New research addresses one of the biggest challenges in tissue engineering: creating lifelike tissues and organs with functioning vasculature - networks of blood vessels that can transport blood, nutrients, waste and other biological materials - and do so safely when implanted inside the body. Researchers from other labs have used different 3D printing technologies to create artificial blood vessels. But existing technologies are slow, costly and mainly produce simple structures, such as a single blood vessel - a tube, basically. These blood vessels also are not capable of integrating with the body's own vascular system. "Almost all tissues and organs need blood vessels to survive and work properly. This is a big bottleneck in making organ transplants, which are in high demand but in short supply. 3D bioprinting organs can help bridge this gap, and our lab has taken a big step toward that goal."

The researchers have 3D printed a vasculature network that can safely integrate with the body's own network to circulate blood. These blood vessels branch out into many series of smaller vessels, similar to the blood vessel structures found in the body. The team developed an innovative bioprinting technology, using their own homemade 3D printers, to rapidly produce intricate 3D microstructures that mimic the sophisticated designs and functions of biological tissues. Researchers first create a 3D model of the biological structure on a computer. The computer then transfers 2D snapshots of the model to millions of microscopic-sized mirrors, which are each digitally controlled to project patterns of UV light in the form of these snapshots. The UV patterns are shined onto a solution containing live cells and light-sensitive polymers that solidify upon exposure to UV light. The structure is rapidly printed one layer at a time, in a continuous fashion, creating a 3D solid polymer scaffold encapsulating live cells that will grow and become biological tissue.

"We can directly print detailed microvasculature structures in extremely high resolution. Other 3D printing technologies produce the equivalent of 'pixelated' structures in comparison and usually require sacrificial materials and additional steps to create the vessels." And this entire process takes just a few seconds - a vast improvement over competing bioprinting methods, which normally take hours just to print simple structures. The process also uses materials that are inexpensive and biocompatible. Using their technology, the team printed a structure containing endothelial cells, which are cells that form the inner lining of blood vessels. Researchers cultured several structures in vitro for one day, then grafted the resulting tissues into skin wounds of mice. After two weeks, the researchers examined the implants and found that they had successfully grown into and merged with the host blood vessel network, allowing blood to circulate normally. The implanted blood vessels are not yet capable of other functions, such as transporting nutrients and waste. "We still have a lot of work to do to improve these materials. This is a promising step toward the future of tissue regeneration and repair."

Link: http://jacobsschool.ucsd.edu/news/news_releases/release.sfe?id=2142

Chimeric Antigen Receptor Cancer Immunotherapies Continue to Look Promising

Cancer treatments based on the use of chimeric antigen receptors are one of the more promising of present forms of immunotherapy. In trials they are producing good results in patients with late stage leukemia and lymphoma, who lack any other options, and are comparatively fragile and beaten down by the combination of disease and prior aggressive treatments. They should do even better once deployed earlier, for patients who have not run this gauntlet. In cancer, as in many things, the earlier the intervention the better the prognosis.

Six months after receiving infusions of their own T cells - genetically engineered ex vivo to carry chimeric antigen receptors (CAR) that bind to proteins on the surface of tumor cells - more than one-third of patients with aggressive lymphomas are seemingly disease free, Kite Pharma announced. The results of this six-month follow up in the Phase 2 trial "showed only a slight degradation in response rates and no new safety concerns compared to results previously seen at three months," according to the statement released by the company. "Kite intends to submit a marketing application for the treatment called KTE-C19 to the US Food and Drug Administration by the end of March."

Last year, both Juno Therapeutics and Kite Pharma announced that a small number of patients had died in their respective CAR T-cell therapy trials. Juno's trial was halted, but Kite's carried on. The Kite study enrolled 77 patients with advanced diffuse large B-cell lymphoma (DLBCL) and 24 patients with two other forms of aggressive lymphomas. Combined, 36 percent of those patients - all of which had stopped responding to all previous treatments - showed no detectable cancer at six months following treatment, and 82 percent of patients experienced shrinkage of their cancer by half or more. Most importantly, no additional safety issues beyond the three patient deaths already reported (two of which were believed to be the result of treatment) arose.

With the field facing safety concerns with the new type of treatment, researchers have anxiously awaited the results of ongoing trials by Kite Pharma and Novartis. Novartis is right on Kite's heels in the race to market a CAR-T therapy, with the company expected to file with the FDA for approval of its lead CAR-T therapy, CTL019, for a rare pediatric blood cancer called acute lymphoblastic leukemia.

Link: http://www.the-scientist.com/?articles.view/articleNo/48649/title/Kite-s-CAR-T-Cell-Therapy-Success/

Senescent Cells Make Everything Worse in the Aging Lungs

Here I'll point out a recent open access paper that covers the various ways in which accumulated senescent cells harm the lungs in old age. The count of senescent cells rises with age in all tissues, the consequence of increased cellular damage on the one hand and progressive failure of the immune system to destroy these cells on the other. The presence of these cells is one of the contributing root causes of aging, in fact. They generate a mix of signals known as the senescence-associated secretory phenotype (SASP) that promotes chronic inflammation, destructively remodels the extracellular matrix structures necessary for correct tissue function, and changes the behavior of nearby cells for the worse. When it comes to the lungs, it is already known that senescent cells make people more vulnerable to respiratory infection, and are responsible for loss of elasticity and degraded normal function of structures in the lungs. Further, senescent cells are strongly implicated as a cause of fatal lung diseases such as idiopathic pulmonary fibrosis, due to their harmful effects on tissue structure.

If senescent cells are such a bad deal, why do we have them? The short answer is that evolution tends to produce systems that work well at the outset, during reproductive life span, and then fall over badly later. The antagonistic pleiotropy view of the evolution of aging describes this picture in more detail; in essence there is little evolutionary pressure after the end of reproductive life to select for a biochemistry with improved repair and maintenance. Senescent cells are initially one of the mechanisms that shape a growing embryo, helping to stop growth when growth must end, such as around fingers, or defining the edges of other organs. They also play a short-term role in wound healing. Further, at least initially and in small amounts, cellular senescence can suppress the risk of cancer by halting replication in those cells most at risk of becoming cancerous. Unfortunately, despite the necessary and useful aspects of cellular senescence, the bad behavior of senescent cells in large numbers eventually kills us.

What is to be done about this? The most straightforward approach is to develop targeted cell killing therapies that destroy senescent cells while leaving normal cells alone. Senescent cell clearance has been demonstrated to produce limited rejuvenation in mice, turning back numerous specific aspects of aging and age-related diseases, and a range of approaches to bring this capability to human medicine are currently at various stages of development. Small molecule drugs that trigger apoptosis in senescent cells are the furthest along, and are entering clinical trials this year and next. Beyond that, groups like Oisin Biotechnologies are working on programmable gene therapies and other approaches that should prove more effective than the output of the traditional drug discovery pipeline. This will all cascade into the clinic over the course of the next decade, starting a year or two from now, and given the benefits we should all be putting some funds aside for our own treatment when it becomes available at a reasonable price.

The Impacts of Cellular Senescence in Elderly Pneumonia and in Age-Related Lung Diseases That Increase the Risk of Respiratory Infections

Pneumonia causes significant mortality and morbidity in elderly patients, defined as those aged over 65 years, compared to younger populations. The annual incidence of pneumonia in the elderly populations is 4 times that of younger populations. In addition, the rates of hospitalization for pneumonia increase in elderly patients with each passing year, and with an expected 20% of the world's population reaching elderly status by 2050, the burden of community-acquired pneumonia will be even more significant in the coming years. In the respiratory system, aging might render individuals more susceptible to infection by undergoing various physiological changes, including dilatation of airspaces, increased air trapping, decreased chest wall compliance, reduced respiratory strength, decline in mucociliary clearance, and diminishment of cough reflex. In addition, aging weakens the immune system in conjunction with the presence of comorbid diseases (e.g., diabetes mellitus, chronic heart disease, malignant tumors, and use of immunosuppressive drugs). However, the definitive mechanisms underlying the high morbidity and mortality of pneumonia in elderly populations are not fully understood.

Several lines of evidence indicate that age-associated, nonmicrobial, and chronic low-grade inflammation enhances the susceptibility of pneumonia in the elderly populations. A previous study reported that elevated tumor necrosis factor (TNF)-α and interleukin (IL)-6 levels positively correlated with the incidence of pneumonia in healthy elderly individuals. Other studies demonstrated that aged mice had increased lung inflammation and were found to be highly susceptible to pneumococcal pneumonia.

Cellular senescence, one of the hallmarks of aging, carries out its primary duty as a trigger of tissue repair, regeneration, and remodeling during normal embryonic development and upon tissue damage. To eliminate damaged cells, senescent cells arrest their own proliferation, create an inflammatory microenvironment, recruit phagocytic immune cells for elimination of senescent cells through senescence-associated secretory phenotype (SASP), and promote tissue renewal. These processes are beneficial for organisms in young tissue where the sequence of senescence-clearance-regeneration is transient in manner. However, this beneficial processes can be corrupted in a pathological context and aged tissues, where senescent cells persistently accumulate. The combination of senescent cell accumulation and excessive SASP results in persistent low-grade inflammation in aging tissue, which elevates the susceptibility to pathogen threats. Furthermore, accumulation of senescent cells causes disruption of normal tissue microenvironments and aberrant tissue remodeling through extracellular matrix (ECM) degeneration and tissue fibrosis.

In the respiratory system, emerging evidence indicates that cellular senescence is a key component in the pathogenesis of chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), which are known to be age-related diseases and increase the vulnerability to pneumonia. Both of the diseases bear the feature of chronic low-grade inflammation with upregulations of various growth factors and chemokines. Thus, it is speculated that COPD and IPF might enhance the vulnerability to pathogens not only by their structural collapse of lung parenchyma, which makes it easier for pathogens to invade, but also by inducing chronic low-grade inflammation due to SASP. Since both of the lung disorders predominantly affect the elderly and have a lot of involvement in the susceptibility to the pathogens, we contemplate that it is also important to focus on the involvement of cellular senescence in the pathogenesis COPD and IPF for getting to the core of elderly pneumonia.

The Impact of Protein Aggregation on Mitochondria

Aging is characterized by an increased presence in tissues of protein aggregates, solid deposits of misfolded proteins and metabolic waste. This increase is perhaps largely driven by the progressive damage and failure of mechanisms of clearance, such as those associated with the proteasome and lysosome, as well as the activities of the immune system. Here, researchers investigate the impact of aggregates on another vital cellular system, the mitochondria. In many age-related conditions characterized by the presence of aggregates and waste, mitochondrial dysfunction also occurs. Is this an example of independent aspects of aging correlating simply because the condition is age-related, or is there direct causation in this relationship?

Working with yeast and human cells, researchers have discovered an unexpected route for cells to eliminate protein clumps that may sometimes be the molecular equivalent of throwing too much or the wrong trash into the garbage disposal. Proteins in the cell that are damaged or folded incorrectly tend to form clumps or aggregates, which have been thought to dissolve gradually in a cell's cytoplasm or nucleus thanks to an enzyme complex called the proteasome, or in a digestive organelle called the lysosome. But in experiments on yeast, which has many structures similar to those in human cells, scientists unexpectedly found that many of those protein clumps break down in the cell's energy-producing powerhouses, called mitochondria. They also found that too many misfolded proteins can clog up and damage this vital structure.

The team's findings could help explain why protein clumping and mitochondrial deterioration are both hallmarks of neurodegenerative diseases. In a previous study, researchers found protein aggregates, which form abundantly under stressful conditions, such as intense heat, stuck to the outer surface of mitochondria. In this study, they found the aggregates bind to proteins that form the pores mitochondria normally use to import proteins needed to build this organelle. If these pores are damaged by mutations, then aggregates cannot be dissolved, the researchers report. These observations led the team to hypothesize that misfolded proteins in the aggregates are pulled into mitochondria for disposal. Testing this hypothesis was tricky, because most of the misfolded proteins started out in the cytoplasm, and most of those that enter mitochondria quickly get ground up.

As a consequence, the team used a technique in which a fluorescent protein was split into two parts. Then, they put one part inside the mitochondria and linked the other part with a misfolded and clumping protein in the cytoplasm. If the misfolded protein entered the mitochondria, the two parts of the fluorescent protein could come together and light up the mitochondria. This was indeed what happened. To see what might happen in a diseased system, the team then put into yeast cells a protein implicated in the neurodegenerative disease known as amyotrophic lateral sclerosis (ALS). After a heat treatment that caused the ALS protein to misfold, it also wound up in the mitochondria. The researchers then did an experiment in which a lot of proteins in the cytoplasm were made to misfold and found that when too much of these proteins entered mitochondria, they started to break down.

Biological systems are in general quite robust, but there are also some Achilles' heels that may be disease prone, and relying on the mitochondrial system to help with cleanup may be one such example. While young and healthy mitochondria may be fully up to the task, aged mitochondria or those overwhelmed by too much cleanup in troubled cells may suffer damage, which could then impair many of their other vital functions.

Link: https://www.eurekalert.org/pub_releases/2017-03/jhm-icu022817.php

An Approach to Reversing Aspects of Aging in the Blood Stem Cell Niche

Stem cell activity declines with age, and for at least some types of stem cell this is as much a matter of signaling and environment changes as is is a matter of accumulated molecular damage to the stem cell lineages themselves. Stem cells reside within a niche of supporting cells, and it is damage and change within that niche that is responsible to some degree for loss of stem cell activity, and thus progressive failure of the tissues maintained by those stem cells. This is a potential target for therapy: researchers here make an attempt to force a more youthful pattern of cell signaling onto the bone marrow niche within which hematopoietic stem cells reside, those responsible for generating blood and immune cells. This fails to address the underlying cellular damage that causes change, but appears to be capable of producing some benefits.

As people get older so do the hematopoietic stem cells (HSCs) that form their blood. In a new study, scientists propose rejuvenating the bone marrow niche where HSCs are created. This could mean younger acting HSCs that form healthier blood cells, boosted immunity in older people, and a better defense mechanism against certain cancers. The researchers conducted a number of experiments to test the formation and vitality of cells in and near the bone marrow microenvironment. One test in aging mice looked at the formation of endosteum stroma cells, which form a thin layer of connective tissue on the inner surface of bones. Another experiment monitored levels of osteopontin and other proteins linked to distinct cells in bone marrow during the aging process. Study authors say they observed reduced production of osteoblasts and other stroma cells in the endosteum of older mice. They also saw decreased osteopontin protein levels in the bone marrow of older animals, which they note was associated with reduced vigor and function of blood-forming HSCs.

Scientists followed up the earlier experiments by transplanting bone marrow cells from older mice (19-21 months) into young mice (8 to 10 weeks). In two other experiments, the authors also transplanted aged HSCs from older mice into younger mice, and they treated aged HSCs with a recombinant form of the osteopontin protein. Transplantation into the younger animals caused cells to act in a younger more vital manner, the authors report. This includes the presence of smaller numbers of HSCs with greater potential for forming different types of blood cells, which included larger populations of B and T cells and smaller production of myeloid cells.

The authors also saw aged HSCs treated with recombinant osteopontin regain their youthful characteristics and capacity to form different blood-cell types. Also observed was diminished signaling of the protein Cdc42, a protein previously shown to cause HSCs to age. Osteopontin levels are not only low in the bone marrow niche, but also in the blood upon aging. As a follow up to the current study, the researchers are investigating the possibility to use osteopontin replacement therapy in mice to counter the influence of an aging niche directly in the animals.

Link: https://www.cincinnatichildrens.org/news/release/2017/bone-marrow-stem-cell

A Method of Rapidly Warming Vitrified Organs with Minimal Damage

Today I'll point your attention to a most interesting paper on a novel approach to reviving vitrified tissues. Vitrification is a state induced in tissues through the use of cryoprotectant and very low temperatures. All biological molecular activity halts, and the tissue enters a glass-like state of minimal ice crystal formation in which the small-scale structures essential to function are well preserved, or at least to the extent that the process is performed well and cryoprotectant is completely diffused throughout the tissue. Reversing this process without killing cells and essentially destroying the living tissue is another story, however. It cannot be done reliably today, but seems like a very feasible near future goal. Low-temperature storage of cells and other very small amounts of biological materials is well established, and lower animals such as nematode worms can survive vitrification and thawing. Further, researchers have demonstrated vitrification, thawing, and transplant of a mammalian organ that functioned for at least a short time. These are starting points, and a number of research groups are trying to close the various gaps in reliability and technology to enable a robust methodology.

Reversible vitrification of large tissue sections is an important goal for many reasons. Firstly, it would revolutionize the logistics of the organ transplant industry, which is currently expensive and challenging because organs cannot be kept alive for long once available, among other reasons. Secondly it would similarly revolutionize the logistics of the tissue engineering industry that has yet to exist but lies not so far ahead in our future. The ability to create supplies of tissues and organs far ahead of time and store them safely and indefinitely will shape much of the economics of this field. Lastly, and most importantly for the long term, the cryonics industry needs a way to safely warm the people who have been cryopreserved at death, at some future date when rejuvenation therapies, regenerative medicine, and other necessary biotechnologies have advanced to the point at which it is possible to restore or replace an old body and brain, even working from the starting point of a warming individual just past the point of today's clinical death. These individuals took a brave leap into the unknown, and at some point it will become possible to revive them. Even before that time, concrete progress towards reversible vitrification of tissues will greatly increase the legitimacy of cryonics in the eyes of the world. If a kidney can be vitrified, thawed, and used in medicine, its fine structures intact, then why can't a brain and the mind it contains be preserved, or so the line of thought will run.

In the case of the technology demonstrated here, it would most likely be very challenging to apply it to people already preserved, as it involves additions to the cryoprotectant solution. Introducing those additions after the fact would no doubt require technology of the same order of advancement as would be needed to restore aged tissues and manage a safe return to life on thawing. If there is one approach, however, there will be others - and for the people who have yet to be cryopreserved, those who will age to death prior to the advent of comprehensive human rejuvenation therapies, this class of approach is still very relevant. That this can be done at all should also increase any careful assessment of the odds of the whole endeavor of cryonics succeeding for those involved. Time passes and progress is forged, and more rapidly than ever these days.

New technology rewarms large-scale tissues preserved at low temperatures

A research team has discovered a groundbreaking process to successfully rewarm large-scale animal heart valves and blood vessels preserved at very low temperatures. The discovery is a major step forward in saving millions of human lives by increasing the availability of organs and tissues for transplantation through the establishment of tissue and organ banks. "This is the first time that anyone has been able to scale up to a larger biological system and demonstrate successful, fast, and uniform warming hundreds of degrees Celsius per minute of preserved tissue without damaging the tissue."

In the past, researchers were only able to show success at about 1 milliliter of tissue and solution. This study scales up to 50 milliliters, which means there is a strong possibility they could scale up to even larger systems, like organs. Currently, more than 60 percent of the hearts and lungs donated for transplantation must be discarded each year because these tissues cannot be kept on ice for longer than four hours. Long-term preservation methods, like vitrification, that cool biological samples to an ice-free glassy state using very low temperatures between -160 and -196 degrees Celsius have been around for decades. However, the biggest problem has been with the rewarming. Tissues often suffer major damage during the rewarming process making them unusable, especially at larger scales.

In this new study, the researchers addressed this rewarming problem by developing a revolutionary new method using silica-coated iron oxide nanoparticles dispersed throughout a cryoprotectant solution that included the tissue. The iron oxide nanoparticles act as tiny heaters around the tissue when they are activated using noninvasive electromagnetic waves to rapidly and uniformly warm tissue at rates of 100 to 200 degrees Celsius per minute, 10 to 100 times faster than previous methods. After rewarming and testing for viability, the results showed that none of the tissues displayed signs of harm, unlike control samples rewarmed slowly over ice or those using convection warming. The researchers were also able to successfully wash away the iron oxide nanoparticles from the sample following the warming. Although scaling up the system to accommodate entire organs will require further optimization, the authors are optimistic. They plan to start with rodent organs (such as rat and rabbit) and then scale up to pig organs and then, hopefully, human organs.

Improved tissue cryopreservation using inductive heating of magnetic nanoparticles

Vitrification, a kinetic process of liquid solidification into glass, poses many potential benefits for tissue cryopreservation including indefinite storage, banking, and facilitation of tissue matching for transplantation. To date, however, successful rewarming of tissues vitrified in VS55, a cryoprotectant solution, can only be achieved by convective warming of small volumes on the order of 1 ml. Successful rewarming requires both uniform and fast rates to reduce thermal mechanical stress and cracks, and to prevent rewarming phase crystallization. We present a scalable nanowarming technology for 1- to 80-ml samples using radiofrequency-excited mesoporous silica-coated iron oxide nanoparticles in VS55.

Advanced imaging including sweep imaging with Fourier transform and microcomputed tomography was used to verify loading and unloading of VS55 and nanoparticles and successful vitrification of porcine arteries. Nanowarming was then used to demonstrate uniform and rapid rewarming at more than 130°C/min in both physical (1 to 80 ml) and biological systems including human dermal fibroblast cells, porcine arteries and porcine aortic heart valve leaflet tissues (1 to 50 ml). Nanowarming yielded viability that matched control and/or exceeded gold standard convective warming in 1- to 50-ml systems, and improved viability compared to slow-warmed (crystallized) samples. Last, biomechanical testing displayed no significant biomechanical property changes in blood vessel length or elastic modulus after nanowarming compared to untreated fresh control porcine arteries. In aggregate, these results demonstrate new physical and biological evidence that nanowarming can improve the outcome of vitrified cryogenic storage of tissues in larger sample volumes.

Lack of Exercise and Excess Weight Increases Risk of Untreatable Heart Failure

If you were in search of yet more reasons to keep up with the health basics, meaning regular exercise, a sensible diet, and avoidance of weight gain, then look no further. Here, researchers note that a sedentary lifestyle and excess weight in the form of visceral fat tissue significantly increase the odds of suffering a class of heart failure that currently lacks any good form of treatment.

Heart failure is a chronic condition in which the heart is unable to supply enough oxygenated blood to meet the demands of the body. Heart failure is approximately equally divided between two subtypes: heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). The ejection fraction refers to the percentage of the blood that exits the heart with each contraction. "Previous studies have consistently found an association between low levels of physical activity, high body mass index (BMI), and overall risk of heart failure, but this study shows that the association is more pronounced for heart failure with preserved ejection fraction, the type of heart failure that is the most challenging to treat."

In heart failure with preserved ejection fraction, the heart stiffens. Instead of being soft, it's rigid and it resists expansion. Cardiologists often explain the difference between the two types of heart failure by saying that in heart failure with preserved ejection fraction, the heart doesn't relax enough, while in heart failure with reduced ejection fraction the heart doesn't squeeze enough. Many treatments have been developed for treating the latter but there are no evidence-based treatments for the former. "The five-year survival rate among heart failure with preserved ejection fraction patients is around 30 to 40 percent. While heart failure with reduced ejection fraction survival has improved significantly over the years, heart failure with preserved ejection fraction prognosis is little changed."

The pooled analysis looked at data from 51,000 participants in three cohort studies, the Women's Health Initiative, the Multiethnic Study of Atherosclerosis (MESA), and the Cardiovascular Health Study. Among the 51,000 participants, there were 3,180 individuals who developed heart failure. Of these, 39 percent were heart failure with preserved ejection fraction, 29 percent were heart failure with reduced ejection fraction, and 32 percent had not been classified when the data was gathered. The incidence of heart failure with preserved ejection fraction was 19 percent lower for individuals who exercised at recommended levels. Similarly, body mass index (BMI) had an inverse relationship with heart failure with preserved ejection fraction. Higher BMI levels were more strongly associated with heart failure with preserved ejection fraction than with heart failure with reduced ejection fraction.

Link: http://www.utsouthwestern.edu/newsroom/news-releases/year-2017/feb/heart-failure-berry.html

Protective Effects of Physical Activity

Regular exercise slows aging more reliably and to a greater degree than any presently available medical technology, something that is more a statement on the poor nature of medicine at present than on the wondrous powers of exercise. The size of the effect is still small in the grand scheme of things; you can't reliably exercise your way to living to 100, and at present the majority of fit older people don't even make it to 90. You will, however, be better off than people who live a sedentary lifestyle. That exercise is better than available medicines at influencing the pace of aging will cease to be true in the near future as the first rejuvenation therapies emerge, but even then there is no reason to use that as excuse to slack on the basics of health maintenance. Exercise is both free and produces benefits, so take advantage.

Some lifestyle factors, such as physical activity (PA), could lower the risk of certain forms of dementia. In this article, our goal is to explore the role of PA in reducing the risks of age-related Alzheimer's disease (AD), vascular dementia (VaD), and mild cognitive impairment (MCI). PA throughout one's life can enhance cognitive function later in life, so it should be encouraged at every age. In contrast, sedentary behaviors, such as viewing television for extended periods over the course of years, can negatively affect cognitive function later in life. Moreover, those who were physically active in midlife have a reduced risk of developing depression in late life. Depression in late life has also been linked to dementia. Ideally, all adults should remain physically active throughout life, starting at a young age, to achieve optimal cognitive health as an older adult.

PA is effective in reducing risk for developing MCI in older adults, but the optimizing of exercise training (i.e., types of PA, intensity, duration), cardiorespiratory fitness, age, level of cognition, medications, and social environments, may all play roles in the outcome. For older adults who have already developed a form of cognitive impairment, whether mild, such as those with MCI, or moderate to severe, as with dementia, PA can improve cognitive function, when compared to those with cognitive impairment who are not physically active. Studies show that six to 12 months of exercise for those with MCI or dementia results in better cognitive scores than sedentary controls.

While the protective effect of PA on the aging brain is supported by numerous studies, the exact mechanisms are less clear. PA can increase blood flow to the brain, both during and shortly after a PA event, in response to increased needs for oxygen and energetic substrate. The increased brain/cerebral blood flow triggers various neurobiological reactions, which provide an increased supply of nutrients. Moreover, cerebral angiogenesis - the development of new blood vessels in the brain - is increased by PA, and the brain's vascular system is plastic, even in old age. The increased vascularization of the brain, as well as the regular increases in blood flow that periods of PA provide, may reduce the risks of MCI and AD, by nourishing more brain cells and helping to remove metabolic waste or AD-inducing amyloid-β.

Hypertension is one of the main risk factors for MCI, AD, and VaD. Hypertension can increase the risk of strokes, as well as small strokes that are often the cause of VaD. Since strokes can complicate AD and aggravate dementia symptoms, it follows that hypertensive individuals could benefit by lowering their blood pressure, regardless of their level of cognitive impairment. Even low-intensity PA for 30 min, three to six times a week for nine months, can significantly lower blood pressure in elderly adults. Because hypertension is a prominent risk factor, lowering blood pressure may be one of the mechanisms by which PA reduces the risk of many age-related neurodegenerative diseases.

Link: http://www.mdpi.com/2076-3425/7/2/22/htm