An Example of the Importance of Gut Microbiota to Aging in Flies

If we paint with very broad strokes, we can say that flies generally die from intestinal failure in the same way that humans generally die from cardiovascular failure. For flies, the intestine is at the center of the mechanisms determining the pace and manifestations of aging in that species, and the cause of a majority of deaths. While being far from the only organ to consider in fly aging, it does appear to take center stage. Bear this in mind while looking at the research noted here.

All in all, it isn't too surprising to hear that researchers have been able to demonstrate a 60% life extension in flies through a method that involves suppressing some of the detrimental age-related changes in gut bacteria. (Though it appears that almost everything else of interest to the aging process in metabolism is also adjusted via the approach taken here - which makes it hard to ascribe the outcome to any one specific item). In recent years the research community has given ever more attention to the activities of the microbial population of the intestines in various species including our own. Evidence suggests thatthe way in which populations of gut bacteria change over a life span are influential in aging to a degree that may be in the same ballpark as, say, exercise or other noteworthy environmental factors.

Nonetheless, I think caution is wise when extrapolating any research of this nature carried out in flies, given the enormous importance of intestinal function in fly aging. It would be logical to expect to find similar effects in mammals, but nowhere near as large in their consequences. The intestine doesn't seem as central to aging in mammals as it is in flies: the importance of various organs and bodily systems shifts and becomes more distributed as one moves from lower to higher animals. Quite aside from this, we should remember that there are many ways to significantly extend life in short-lived species such as flies that (a) touch on the mechanisms affected here, and (b) are known to do little for human longevity. Large numbers in life extension mean little on their own when demonstrated in worms, flies, and the like.

When thinking about the mechanisms involved in the connection between gut bacteria and aging, inflammation is likely one of the most important. Gut microbes interact with the immune system, and some are more capable of provoking inflammatory reactions. If, for reasons relating to the many complex changes in lifestyle and immune function and other tissues that occur with age, more inflammatory bacteria come to dominate, then that will cause harm over the long term. There are, however, a growing number of other more subtle mechanisms to consider. Given the comparative recency of this part of the field of aging research, it is fair to say that much remains to be discovered.

The secret to longevity is in the microbiome and the gut

Scientists fed fruit flies with a combination of probiotics and an herbal supplement called Triphala that was able to prolong the flies' longevity by 60% and protect them against chronic diseases associated with aging. The study adds to a growing body of evidence of the influence that gut bacteria can have on health. The researchers incorporated a synbiotic - made of probiotics with a polyphenol-rich supplement - into the diet of fruit flies. The flies fed with the synbiotic lived up to 66 days old - 26 days more than the ones without the supplement. They also showed reduced traits of aging, such as mounting insulin resistance, inflammation, and oxidative stress.

"Probiotics dramatically change the architecture of the gut microbiota, not only in its composition but also in respect to how the foods that we eat are metabolized. This allows a single probiotic formulation to simultaneously act on several biochemical signaling pathways to elicit broad beneficial physiological effects, and explains why the single formulation we present in this paper has such a dramatic effect on so many different markers. The effects in humans would likely not be as dramatic, but our results definitely suggest that a diet specifically incorporating Triphala along with these probiotics will promote a long and healthy life."

The findings can be explained by the "gut-brain axis," a bidirectional communication system between microorganisms residing in the gastrointestinal tract - the microbiota - and the brain. In the past few years, studies have shown the gut-brain axis to be involved in neuropathological changes and a variety of conditions such as irritable bowel syndrome, neurodegeneration, and even depression. Few studies, however, have successfully designed gut microbiota-modulating therapeutics having effects as potent or broad as the formulation presented in the new study.

Longevity extension in Drosophila through gut-brain communication

The gut microbiota is complex ecosystem of bacteria, fungi, and microorganisms residing in the gastrointestinal tract, which impart many health benefits onto the host. Distinct variations in the composition of the gut microbiota in the elderly have been identified and could contribute to frailty, disease development and aging itself. A diet rich in probiotics and prebiotics may help prevent chronic age-related disease. Changes in the gut microbiota of aging individuals has a high inter-individual variability due to disease manifestation, medication, diet, and environmental exposure.

In general, aging subjects have a decline in the phyla Firmicutes, elevation in Bacteriodetes, reduction of Bifidobacteria, elevation in the proinflammatory Proteobacteria accompanied by a decline in overall diversity, which is associated with various health risks and fraility. Indeed, a general decrease in the level of short-chain fatty acids (SCFAs) is apparent in aging individuals which is linked to inflammation and adipose tissue dysregulation.

The gut-brain-axis (GBA) is a bidirectional communication system between the gastrointestinal tract microbiota and the brain including various metabolic, immunological, endocrine, and neuronal signals derived from individual bacterial cells and their metabolites. Through this axis, the gut microbiota was recently identified as a target for therapeutic intervention against age-related diseases. For example, several probiotic bacteria have shown beneficial effects in managing symptoms of neurodegeneration.

The present study describes how a novel probiotic and synbiotic formulation impacts Drosophila melanogaster longevity through mechanisms of the GBA. It was previously shown that the probiotic and synbiotic formulation used in the present study has beneficial effects on aging. The present probiotic and synbiotic formulations showed combinatorial action on reducing markers of physiological stress, oxidative stress, inflammation and mitochondrial electron transport chain complex integrity therefore targeting most of the main aging mechanisms. This action benefits not only longevity but would prevent many age-related chronic diseases that are associated with the aforementioned states.

Beclin-1 Mutant Mice Live 10% Longer Due to Enhanced Autophagy

Autophagy is the name given to a collection of cellular housekeeping processes responsible for recycling damaged or unwanted proteins and cellular structures, preventing them from causing further harm within the cell. Many of the methods of modestly slowing aging in laboratory species are observed to involve increased levels of autophagy. For some, such as calorie restriction, there is evidence to demonstrate that functional autophagy is required for aging to be slowed.

Researchers have long been interested in developing pharmaceutical means to enhance autophagy as a form of therapy. This is arguably even more the case these days, now that treating aging as a medical condition is considered to be a respectable goal. Despite the many years of work, therapeutic enhancement of autophagic processes has yet to progress all that far the laboratory, however. Trials have been conducted, but reliable, safe autophagy enhancing drugs have yet to emerge at the far side. The research here is one of many examples in which researchers identify a possible target mechanism for further development.

Researchers found that mice with persistently increased levels of autophagy - the process a cell uses to dispose of unwanted or toxic substances that can harm cellular health - live longer and are healthier. Specifically, they have about a 10 percent extension in lifespan and are less likely to develop age-related spontaneous cancers and age-related pathological changes in the heart and the kidney.

Twenty years ago, researchers discovered beclin 1 - a key gene in the biological process of autophagy. The group's research has since shown that autophagy is important in many aspects of human health, such as preventing neurodegenerative diseases, combating cancer, and fighting infection. In 2003, the team found that the genetic machinery required for autophagy was essential for the lifespan extension observed in long-lived mutant roundworms. "Since then, it has become overwhelmingly clear that autophagy is an important mechanism necessary for the extended lifespan that is observed when model organisms are treated with certain drugs or when they have mutations in certain signaling pathways. The body's natural ability to perform autophagy declines with aging, which likely contributes to the aging process itself."

Yet a crucial question remained unanswered: Is increased autophagy throughout mammalian life safe and beneficial? In other words, can autophagy extend lifespan and improve healthspan? To answer this question, researchers created a genetically engineered mouse that had persistently increased levels of autophagy. The researchers made a mutation in the autophagy protein Beclin 1 that decreases its binding to another protein, Bcl-2, which normally inhibits Beclin 1's function in autophagy. As the researchers expected, these mice had higher levels of autophagy from birth in all of their organs. "The results suggest that it should be safe to increase autophagy on a chronic basis to treat diseases such as neurodegeneration. Furthermore, they reveal a specific target for developing drugs that increase autophagy - namely the disruption of Beclin 1 binding to Bcl-2."


Researchers Create Bioprinted Human Corneas

The cornea is a good target for tissue engineering efforts in these early years of the field. It is small, easily accessible, comparatively simple in structure, and the processes for corneal transplantation are already well established. Many older people suffer from corneal damage or degeneration of one form or another, and these patients might benefit from the cost-effective availability of corneas generated from their own cells. Bioprinting is one approach to reducing the cost of building such patient-matched tissue sections, and as noted here, researchers have recently reported success in rapidly printing corneas in this way.

The first human corneas have been 3D printed. The technique could be used in the future to ensure an unlimited supply of corneas. At present there is a significant shortage of corneas available to transplant, with 10 million people worldwide requiring surgery to prevent corneal blindness as a result of diseases such as trachoma, an infectious eye disorder. In the proof-of-concept research, stem cells (human corneal stromal cells) from a healthy donor cornea were mixed together with alginate and collagen to create a solution that could be printed, a 'bio-ink'. Using a simple low-cost 3D bio-printer, the bio-ink was successfully extruded in concentric circles to form the shape of a human cornea. It took less than 10 minutes to print.

"Many teams across the world have been chasing the ideal bio-ink to make this process feasible. Our unique gel - a combination of alginate and collagen - keeps the stem cells alive whilst producing a material which is stiff enough to hold its shape but soft enough to be squeezed out the nozzle of a 3D printer. This builds upon our previous work in which we kept cells alive for weeks at room temperature within a similar hydrogel. Now we have a ready to use bio-ink containing stem cells allowing users to start printing tissues without having to worry about growing the cells separately."

The scientists also demonstrated that they could build a cornea to match a patient's unique specifications. The dimensions of the printed tissue were originally taken from an actual cornea. By scanning a patient's eye, they could use the data to rapidly print a cornea which matched the size and shape. "Our 3D printed corneas will now have to undergo further testing and it will be several years before we could be in the position where we are using them for transplants. However, what we have shown is that it is feasible to print corneas using coordinates taken from a patient eye and that this approach has potential to combat the world-wide shortage."


Do FOXA2-Related Changes in the Nuclear Lamina Contribute to Liver Aging?

The structure of the cell nucleus is determined by the nuclear lamina, protein filaments that support the nuclear membrane and anchor the important components within the nucleus. Correct function of the lamina and its component parts are required in order for the cell to carry out vital functions such as nuclear DNA maintenance and repair, gene expression, and cell replication. In a cell with faulty nuclear lamina, the nucleus is misshapen and all these processes run awry. Such cells tend to become senescent in response to internal dysfunction, and cause damage to surrounding tissue via their inflammatory secretions if they are not then destroyed promptly by the immune system. Internal self-destruction mechanisms exist, but problems with gene expression may cause them to fail.

Regular readers will recall that this is the scenario in progeria, a condition with the appearance of accelerated aging. Progeria is caused by mutation in the lamin A gene that codes for a protein that is an important component the nuclear lamina. Progeria patients have dysfunctional, broken cells with misshapen cell nuclei, and as a consequence they die young of cardiovascular disease that is very similar to the conditions such atherosclerosis that normally only affect much older individuals. Researchers have found that lamin A is broken in small amounts over the course of normal aging, with damaging results, but it is an open question as to whether that is significant in comparison to the other causes of aging.

In the research noted here, a more subtle age-related disruption to the nuclear lamina is examined, connected to the behavior of FOXA2 and lamin B1. The researchers focus on liver tissue, and suggest that problems with nuclei in the aged liver cause sufficient change in gene expression to contribute to organ dysfunction and age-related disease. The mechanism seems plausible, but the question as before is the degree to which it occurs, and whether it is possible to definitively tie it to systematic changes in gene expression that are broadly similar in all individuals. That last point seems at least at first a challenge; one might expect problems with nuclear structure to have more random effects on the capacity of a cell to carry out its operations. Nonetheless, it is interesting work and worth a look in the broader context of whether or not the structure of the nucleus is a major, minor, or insignificant process in normal aging.

We could reverse aging by removing wrinkles inside our cells, study suggests

A new finding suggests that fatty liver disease and other unwanted effects of aging may be the result of our cells' nuclei - the compartment containing our DNA - getting wrinkly. Those wrinkles appear to prevent our genes from functioning properly. The location of our DNA inside the cell's nucleus is critically important. Genes that are turned off are shoved up against the nuclear membrane, which encases the nucleus. But with age, our nuclear membranes become lumpy and irregular, and that prevents genes from turning off appropriately.

Looking at a model of fatty liver disease, researchers found that our livers become studded with fat as we age because of the wrinkly nuclear membranes. "When your nuclear membrane is no longer functioning properly, it can release the DNA that's supposed to be turned off. So then your little liver cell becomes a little fat cell." The accumulation of fat inside the liver can cause serious health effects, increasing the risk of type 2 diabetes and cardiovascular disease, even potentially leading to death. The membrane wrinkling stems from a lack of a substance called lamin, a cellular protein that comes in various forms. By putting the appropriate lamin back, we might smooth out the membrane.

Researchers suspect the wrinkling of the nuclear membrane is responsible for unwanted effects of aging in other parts of the body as well. "Every time I give this talk to colleagues, they say, 'Well, do you think this is a universal mechanism?' In my opinion, I think it is."

Changes at the nuclear lamina alter binding of pioneer factor Foxa2 in aged liver

Increasing evidence suggests that regulation of heterochromatin at the nuclear envelope underlies metabolic disease susceptibility and age-dependent metabolic changes, but the mechanism is unknown. Here, we profile lamina-associated domains (LADs) in young and old hepatocytes and find that, although lamin B1 resides at a large fraction of domains at both ages, a third of lamin B1-associated regions are bound exclusively at each age in vivo. Regions occupied by lamin B1 solely in young livers are enriched for the forkhead motif, bound by Foxa pioneer factors.

We also show that Foxa2 binds more sites in Zmpste24 mutant mice, a progeroid laminopathy model, similar to increased Foxa2 occupancy in old livers. Aged and Zmpste24-deficient livers share several features, including nuclear lamina abnormalities, increased Foxa2 binding, de-repression of PPAR- and LXR-dependent gene expression, and fatty liver. In old livers, additional Foxa2 binding is correlated to loss of lamin B1 and heterochromatin at these loci. Our observations suggest that changes at the nuclear lamina are linked to altered Foxa2 binding, enabling opening of chromatin and de-repression of genes encoding lipid synthesis and storage targets that contribute to etiology of hepatic steatosis.

No Cardiovascular Health Benefits Result from Most Common Dietary Supplements

It is well known within the research community that dietary supplements as a class achieve next to nothing for basically healthy people, those lacking any specific deficiency or medical condition that might cause that deficiency. In fact the evidence strongly suggests that some supplements, antioxidants for example, may even be modestly harmful over the long term. This scientific consensus has to compete with the marketing budget of the supplement industry, which seems to be doing fairly well for a community focused on selling a mix of largely useless and mildly harmful products. So studies such as this one continue to roll out, and perhaps one day there will be meaningful change as a result, but I'm not holding my breath.

Treatment and prevention of micronutrient deficiencies with vitamins and minerals in the last two-and-a-half centuries are among the most dramatic achievements in the history of nutritional science. However, interest in micronutrients has shifted recently from prevention of classic deficiency states to prevention of possible subclinical deficiencies and promotion of overall health and longevity using supplemental vitamins and minerals (supplement use). Here, the data are less clear, but supplement use is widespread.

Using the National Health and Nutrition Examination Survey data (1999 to 2012) on 37,958 adults, it was estimated that supplement use was high in 2012, with up to 52% of the population taking supplements. Multivitamins were taken by 31% of the population, vitamin D by 19%, calcium by 14%, and vitamin C by 12%. Despite high supplement use by the general public, there is no general agreement on whether individual vitamins and minerals or their combinations should be taken as supplements for cardiovascular disease (CVD) prevention or treatment.

We conducted a systematic review and meta-analysis of existing systematic reviews and meta-analyses and single randomized controlled trials (RCTs) published in English from 2012 to 2017. Where both supplements and dietary intakes of nutrients in foods were combined as total intakes, data were not used unless supplement data were also presented separately. We assessed those supplements previously reported on by the US Preventive Services Task Force (USPSTF): vitamins A, B1, B2, B3 (niacin), B6, B9 (folic acid), C, D, and E, as well as β-carotene, calcium, iron, zinc, magnesium, and selenium.

The following supplements were associated with no significant effect on CVD outcomes and all-cause mortality: vitamins A, B6, and E; β-carotene; zinc; iron; magnesium; selenium; and multivitamins. In general, the data on the popular supplements (multivitamins, vitamin D, calcium, and vitamin C) show no consistent benefit for the prevention of CVD, myocardial infarction, or stroke, nor was there a benefit for all-cause mortality to support their continued use. At the same time, folic acid alone and B-vitamins with folic acid, B6, and B12 reduced stroke, whereas niacin and antioxidants were associated with an increased risk of all-cause mortality. Overall, the effects were small; the convincing lack of benefit of vitamin D on all-cause mortality is probably the reason for the lack of further studies published since 2013. The effects of folic acid in reducing stroke is also convincing, with a 20% reduction.


Long Non-Coding RNA in the Aging Brain

The first step of gene expression, the process of producing proteins from the genetic blueprint of DNA, is the production of an RNA molecule. This RNA is then used as an intermediary working model from which the final protein is produced. Non-coding RNA molecules are those that do not translate into a protein, but otherwise serve one of a wide variety of purposes in the cell. Many of these non-coding RNA molecules are in some way involved in regulating gene expression; the production of proteins in a cell is a highly complex, many-layered, and dynamic collection of processes. It is also far from being completely mapped in detail in its youthful, fully functional state, never mind the countless changes to that state that take place in reaction to the accumulating molecular damage of aging. There is much yet to be discovered about the roles played by specific RNA molecules in cellular metabolism and its alterations over the course of aging.

Alterations in the aging brain include changes in the epigenetics and transcription of both coding and non-coding regions of the genome. Among non-coding transcripts, long non-coding RNAs (lncRNAs) have recently emerged as key regulators of the molecular processes that underlie age-associated phenotypes. lncRNAs are transcripts that are longer than 200 nucleotides in length with virtually no protein-coding capacity. These transcripts are mostly uniquely expressed in cell types - both spatially and temporally - and are particularly enriched in the brain, where they play functional roles in neuroplasticity, cognition, and differentiation of neural stem cells. Additionally, lncRNAs are known to orchestrate epigenetic processes through their interactions with epigenetic machinery.

This review proposes ways by which lncRNAs may contribute to neural aging and how their functions can be altered across the human lifespan. We discuss that antisense lncRNAs can regulate pathological protein aggregation and that subnuclear compartment specific lncRNAs can regulate neuronal splicing, transcription, and sponging of ion channels in aging. Other pre- and post-transcriptional regulatory roles performed by lncRNAs are also discussed in the context of cognition, neurogenesis, and neurodegeneration in aging, including the possible influence of lncRNAs on the maintenance of the 3D nuclear architecture.

In summary, the coding/non-coding interactome that sustains important processes of cognition and adult neurogenesis may become compromised during neuronal aging. It is not yet known whether changes in the transcription of lncRNAs are reactive, compensatory, or causative of aging. However, rapidly accumulating evidence supports the vital contribution of lncRNAs in neuronal aging.


When I am Eighty-Five

I will be 85 somewhere in the mid 2050s. It seems like a mirage, an impossible thing, but the future eventually arrives regardless of whatever you or I might think about it. We all have a vision of what it is to be 85 today, informed by our interactions with elder family members, if nothing else. People at that age are greatly impacted by aging. They falter, their minds are often slowed. They are physically weak, in need of aid. Perhaps that is why we find it hard to put ourselves into that position; it isn't a pleasant topic to think about. Four decades out into the future may as well be a science fiction novel, a far away land, a tale told to children, for all the influence it has on our present considerations. There is no weight to it.

When I am 85, there have been next to no senescent cells in my body for going on thirty years. I bear only a small fraction of the inflammatory burden of older people of past generations. I paid for the products of companies descended from Oisin Biotechnologies and Unity Biotechnology, every few years wiping away the accumulation of senescent cells, each new approach more effective than the last. Eventually, I took one of the permanent gene therapy options, made possible by biochemical discrimination between short-term beneficial senescence and long-term harmful senescence, and then there was little need for ongoing treatments. Artificial DNA machinery floats in every cell, a backup for the normal mechanisms of apoptosis, triggered by lingering senescence.

When I am 85, the senolytic DNA machinery are far from the only addition to my cells. I underwent a half dozen gene therapies over the years. I picked the most useful of the many more that were available, starting once the price fell into the affordable-but-painful range, after the initial frenzy of high-cost treatments subsided into business as usual. My cholesterol transport system is enhanced to attack atherosclerotic lesions, my muscle maintenance and neurogenesis operate at levels far above what was once a normal range for my age, and my mitochondria are both enhanced in operation and well-protected against damage by additional copies of mitochondrial genes backed up elsewhere in the cell. Some of these additions were rendered moot by later advances in medicine, but they get the job done.

When I am 85, my thymus is as active as that of a 10-year-old child. Gene and cell therapies were applied over the past few decades, and as a result my immune system is well gardened, in good shape. A combination of replacement hematopoietic stem cells, applied once a decade, the enhanced thymus, and periodic targeted destruction of problem immune cells keeps at bay most of the age-related decline in immune function, most of the growth in inflammation. The downside is that age-related autoimmunity has now become a whole lot more complex when it does occur, but even that can be dealt with by destroying and recreating the immune system. By the 2030s this was a day-long procedure with little accompanying risk, and the price fell thereafter.

When I am 85, atherosclerosis is curable, preventable, and reversable, and that has been the case for a few decades. There are five or six different viable approaches in the marketplace, all of which basically work. I used several of their predecessors back in the day, as well. Most people in the wealthier parts of the world have arteries nearly free from the buildup of fat and calcification. Cardiovascular disease with age now has a very different character, focused more failure of tissue maintenance and muscle strength and the remaining small portions of hypertension that are still problematic for some individuals. But that too can be effectively postponed through a variety of regenerative therapies.

When I am 85, there is an insignificant level of cross-linking in most of my tissues, as was the case since my early 60s. My skin has the old-young look of someone who went a fair way down the path before being rescued. Not that I care much about that - I'm much more interested in the state of my blood vessels, the degree to which they are stiff and dysfunctional. That is why removal of cross-links is valuable. That is the reason to keep on taking the yearly treatments of cross-link breakers, or undergo one of the permanent gene therapies to have your cells produce protective enzymes as needed.

When I am 85, I have a three decade patchwork history of treatments to partially clear this form of amyloid or that component of lipofuscin. Modified enzymes are delivered here, a gene therapy applied there. I will not suffer Alzheimer's disease. I will not suffer any of the common forms of amyloidosis that degrade heart muscle performance or disrupt function in other organs. The potential for such conditions is controlled, shut down with the removal of the protein aggregates that cause cellular dysfunction. There is such a breadth of molecular waste, however: while the important ones are addressed, plenty more remain. This is one of the continuing serious impacts to the health of older individuals, and a highly active area of research and development.

When I am 85, I am the experienced veteran of several potentially serious incidences of cancer, all of which were identified early and eradicated by a targeted therapy that produced minimal side-effects. The therapies evolve rapidly over the years: a bewildering range of hyper-efficient immunotherapies, as well as treatments that sabotage telomere lengthening or other commonalities shared by all cancer cells. They were outpatient procedures, simple and quick, with a few follow-up visits, so routine that they obscured the point that I would be dead several times over without them. The individual rejuvenation technologies I availed myself of over the years were narrowly focused, not perfect, and not available as early as I would have liked. Cancer is an inevitable side-effect of decades of a mix of greater tissue maintenance and unrepaired damage.

Do we know today what the state of health of a well-kept 85-year-old will be in the 2050s? No. It is next to impossible to say how the differences noted above will perform in the real world. They are all on the near horizon, however. The major causes of age-related death today will be largely controlled and cured in the 2050s, at least for those in wealthier regions. If you are in your 40s today, and fortunate enough to live in one of those wealthier region, then it is a given that you will not die from Alzheimer's disease. You will not suffer from other common age-related amyloidosis conditions. Atherosclerosis will be reliably controlled before it might kill you. Inflammatory conditions of aging will be a shadow of what they once were, because of senolytic therapies presently under development. Your immune system will be restored and bolstered. The stem cells in at least your bone marrow and muscles will be periodically augmented. The cross-links that cause stiffening of tissues will be removed. Scores of other issues in aging process, both large and small, will have useful solutions available in the broader medical marketplace. We will all live longer and in better health as a result, but no-one will be able to say for just how long until this all is tried.

Exploring the Utility of Decellularized Muscle Grafts in Animal Models

In this open access paper, researchers explore the utility of decellularized muscle grafts to repair severe injury. Decellularization is the process by which a donor tissue is cleared of cells, leaving behind the extracellular matrix. This intricate structure includes capillary networks and chemical cues to guide cells, line items that the research community has yet to reliably recreate when building tissue from scratch. Over the past decade, researchers have demonstrated the ability to repopulate decellularized tissue with patient-derived cells, a capacity that in principle allows for the production of patient-matched donor organs. This is an important stepping stone on the path towards fully tissue engineered organs grown from a cell sample, and offers the potential for incremental improvement over the present situation for organ donation and transplantation. It can expand the donor pool to include tissues that would be rejected, allow the possibility of transplantation across species, and greatly improve patient prognosis by near eliminating transplant rejection issues.

Injuries to the extremities affect soft and hard tissues and can result in permanent loss of skeletal muscle mass, termed volumetric muscle loss (VML). Treatments for VML include muscle transfers or stem cell injections, but they are not effective procedures to restore muscle function and can require additional surgeries and tissue harvest. Extensive research has been done to identify more effective VML treatments using animal models with severe functional deficits. In these models, VML typically exceeds 20% of the affected muscle mass and results in reduced muscle function. Wounds this large are far beyond the natural healing capacity, making them a gold standard for regenerative medicine research.

Extracellular matrix (ECM) structure and chemistry are key elements involved in muscle regeneration and taking advantage of those elements is important to restore function in VML injuries. Muscle ECM is a matrix rich in laminin, fibronectin, collagens, proteoglycans, and growth factors, which play a role in myoblast differentiation and muscle fiber formation. Biomaterials derived from soft tissues can retain these ECM components and have already shown promise. Several decellularized allogenic and xenogenic matrices are currently available for clinical use, but are exclusively produced from thin tissues such as the skin, small intestine submucosa, and bladder. Those thin-walled tissues do not possess specific properties found in skeletal muscle such as alignment and muscle-specific chemistry.

Decellularized muscle matrices (DMMs) retain the native morphology of muscle ECM, support muscle healing, and promote a proregenerative immune response. These matrices release factors in vivo that promote constructive remodeling of tissue by macrophages and suppress a cytotoxic T cell response, resulting in implant integration and tissue regeneration. Properties like these are critical to elicit a regenerative response that activates muscle progenitors (satellite cells and myoblasts) to differentiate into myocytes, and fuse together to form muscle fibers. Without ECM cues to direct muscle progenitors, muscle healing is delayed.

We compared the ability of DMM, autologous muscle grafts (clinical standard), and type I collagen plugs (negative control) to support muscle regeneration. DMM supported regeneration over a 56-day period in 1×1 cm and 1.5×1 cm gastrocnemius muscle defects in rats. Muscle function tests demonstrated improved muscle recovery in rats with DMM grafts when compared to collagen. DMM supported muscle regeneration with less fibrosis and more de novo neuromuscular receptors than either autograft or collagen. Overall, our results indicate that DMM may be used as a muscle replacement graft based on its ability to improve muscle function recovery, promote muscle regeneration, and support new neuromuscular junctions.


Discussing the Dog Aging Project with Matt Kaeberlein

The Life Extension Advocacy Foundation volunteers recently interviewed Matt Kaeberlein on the topic of the Dog Aging Project, a venture that aims to try in dogs some of the more credible and safe interventions shown to modestly slow aging in mice. When initially proposed, senolytics to clear senescent cells were not in that list, but we might hope to see that change in the years ahead. I'm not overly optimistic about the performance of the other possibilities, such as mTOR inhibitors and other candidate calorie restriction mimetic or exercise mimetic pharmaceuticals. In some cases the evidence is good for these items to work, in the sense of improving health and longevity to some degree, but in general we should expect the effects on life span to be small in longer-lived mammals. All of the mechanisms based on enhanced stress responses, such as those triggered by a lack of nutrients or undertaking strenuous exercise, scale down in their effect on life span for longer-lived species; short-lived species have a much greater plasticity of aging in response to environmental circumstances.

Could you tell us the story of Dog Aging Project? How did it all start?

About five years ago, a new recruit to the University of Washington Healthy Aging and Longevity Institute had recently obtained a small grant to develop companion dogs as a model to understand the genetic and environmental determinants of aging. After a series of discussions, it occurred to me that we had an opportunity not just to study aging in dogs but to potentially develop interventions to delay or even reverse aspects of aging in dogs from those that had already been shown to increase lifespan and healthspan in laboratory rodent models. I decided to focus on rapamycin first, because it was (and still is) the most validated and effective pharmacological approach for increasing longevity in mice, and it has the added benefit that it is effective even when initiated in middle age. After spending a couple of months convincing myself that we could safely perform a rapamycin veterinary clinical trial in dogs, I organized a conference in Seattle in 2014, where I pitched the idea. Soon after that, we started getting quite a bit of media attention, and we decided that we should officially form the Dog Aging Project.

What can you tell us about trials you've already run and their results?

So far, we've only completed one trial, a 10-week, randomized, double-blind, placebo-controlled study of rapamycin in pet dogs. The results of that study were as positive as we could have hoped. We saw no evidence for increased side effects in the dogs that received rapamycin and statistically significant improvements in two of the three measures of age-related cardiac function that we looked at.

Are there any trials you're running right now or are preparing to launch soon?

Yes, the Phase 2 rapamycin intervention trial is currently enrolling dogs. That trial is funded by the Donner Foundation and is a one-year trial to, again, assess effects of rapamycin on cardiac function and to also look at effects on cognitive function and activity. Depending on the outcome of our submitted NIH grant, we hope to begin officially enrolling dogs into the Longitudinal Study of Aging and Phase 3 of the rapamycin intervention trial toward the end of 2018 or early 2019. We hope to have an official announcement on the outcome of that proposal within the next 3-4 weeks.

Can I volunteer my dog for the program, and how do I do that?

Anyone can nominate their dog to participate in either the Longitudinal Study of Aging or the Rapamycin Intervention Trials through the Dog Aging Project website. The Longitudinal Study is currently open to all breeds, ages, and sizes of dogs. The Rapamycin Intervention Trials are restricted to healthy dogs of at least 6 years old and at least 40 lbs in weight.


Support for Longevity Science is the Most Effective Form of Philanthropy

The members of the effective altruism community are interested in rationally identifying the most cost-effective ways to make the world a better place, involving both the usual metrics by which we might judge "better," but also an analysis of whether or not those usual metrics are in fact helpful. Tear it all down and build it up again from first principles. Particularly at the large scale, a great deal of the status quo in philanthropy is wasted effort, virtue signaling, or even actively counterproductive. There are many ostensibly charitable organizations that, at best, do no good, and at worst exacerbate the problems they engage with. There are many ways to choose poorly as an individual donor. Philanthropy as an institution and as a personal choice can definitely be improved. The effective altruists are on to something there.

Quite some time ago I decided that the best and most effective form of philanthropy takes the form of supporting efforts that have a good chance of producing progress towards the medical control of aging. The rationale here is simple, possibly unfashionably so. Firstly, aging causes by far the greatest amount of human suffering and death. Secondly, aging is a tractable problem, in that the members of the research community collectively know enough to make progress rather than spinning their wheels, given suitable strategic choices in research and development. Lastly, suffering and death are bad things that should be brought to an end as soon as it is feasible to do so. That last opinion is both ubiquitous, judging by people's actions in their day to day lives, and yet somehow unpopular in our culture, a situation that has long confused me.

If one sets forth to blindly support any and all projects that claim to be doing something about aging, then a good three quarters of what is spent will be wasted. Yet the harms of aging are so great in comparison to other harms that the effort will still create more good in the world by far than for any other rational single choice in philanthropy. Given a little self-education, it is perfectly possible to avoid most of the obvious waste - the fraudulent side of the "anti-aging" marketplace, for example. The more challenging divide lies in the legitimate scientific community, between those focused on ways to modestly slow aging, such as via work on existing drugs like metformin and rapamycin, and those focused on ways to reverse aging, such as via senolytics to destroy senescent cells and the other lines of rejuvenation research advocated by the SENS Research Foundation. Few laypeople new to the field find it easy to determine what is more or less likely to be effective, and why.

I have long looked at this divide and taken the obvious position (obvious to me, anyway) that if funding and time is directed to this field, then it should be directed towards the goal of rejuvenation, not merely slowing aging. Rejuvenation is very much better than a slowing of aging. Rejuvenation via repair of fundamental molecular damage might even be easier to achieve than a method of reliably and safely slowing aging. It requires far less new knowledge about the operation of cellular metabolism, and obtaining that knowledge is slow, uncertain, and expensive. Where we can compare the pace of progress at a given level of funding, calorie restriction mimetic research from the 1990s to today, the best example of attempts to slow aging, looks like a very poor choice in comparison to the past seven years of senolytic development, the best example of attempts to reverse the causes of aging.

Returning to the topic of effective altruism, the article quoted below is an example of the sort of exercise that community specializes in: obtaining a handle on the usefulness of any given project by building a model and putting some numbers into it. The process is the important thing, thinking about it methodically, not any specific answer. In this case the analysis focuses on the TAME trial for metformin in older adults. This is a great example of work that I think has little technical merit. The evidence for metformin to reliably slow aging is terrible, the results from individual studies all over the map. Even if we take the best results as indicative of its performance, which given the full scope of the data seems unlikely, then the outcome is still significantly worse than the expected, reliable outcomes of more exercise and fewer calories. If someone can run the numbers on efforts to push forward metformin as a treatment for aging and find it to be a highly effective use of time and funding, then this says much more about the urgency of treating aging - and the waste in so much of the rest of philanthropy - than it does about the viability of metformin. Take that urgency and direct it to a better project, such as senolytics, or anything else under the SENS rejuvenation research umbrella.

Expected cost per life saved of the TAME trial

In this post I will try to calculate the expected cost per life saved of the Targeting Aging With Metformin (TAME) trial, in an attempt to improve Turchin's estimate. I found some of Turchin's assumptions were unnecessary or unjustified. He didn't provide an expected value calculation and he didn't apply the necessary discounts. His figure is true only if some of his many assumptions are, and this led to a result that I thought to be many orders of magnitudes off: $0.24 per life saved. In reality, if you look at the calculation section, you can see that, accounting for the icebreaking effect of the TAME trial on the FDA, I came to a result that isn't distant to Turchin's. This happened because Turchin didn't account for the icebreaking effect, compensating the omission of the discounts. Otherwise, if the icebreaking effect is disregarded, the results are different, yet still show high cost-effectiveness.

The TAME (Targeting Aging With Metformin) trial is motivated by two reasons: 1) According to AFAR, the TAME trial could have an icebreaking effect on the FDA. It will pave the way for the Food and Drug Administration (FDA) to consider aging a modifiable condition and an official indication for which treatments can be developed and approved, and 2) Testing metformin on a healthy population could prove its beneficial effects, and the approval of metformin by the FDA would cause physicians to start suggesting it to their patients.

The core of Turchin's idea is right: Let's say Longevity Escape Velocity (LEV) will happen at date x. If we extend the lives of people who would have died before date x, making them reach date x, we are then "saving their lives". This could be done by raising the life expectancy of a portion of the world using simple interventions such as metformin, or alternatively by accelerating research to make LEV occur sooner. The given in this rationale is that Longevity Escape Velocity will happen at some point, and I think this is very safe to assume.

Many studies suggest that metformin could postpone age-related pathologies. Data from the largest study translates to around 1 year of more life for diabetics than the non diabetic control. More important is the number of years LEV will be advanced by, considering the icebreaking effect of TAME. The model here shows that most of the cost-effectiveness of TAME comes from its icebreaking effect. Will advancing the date of the icebreaking effect by x years result in an advance of LEV of x years? Probably not, since the FDA not recognising aging as an indication doesn't stop aging research, and it's not clear if the icebreaking effect is a bottleneck for achieving LEV. Such an effect could, though, increase the budget of aging research and make research in this field more focused on translation and on the hallmarks of aging instead of single diseases.

If the icebreaking effect enables the funding of one or more projects which are bottlenecks to LEV, then LEV's date is advanced. The main probability at play here is if the NIH would indeed increase its budget on aging or spend it better. If this doesn't happen I don't anticipate other actors would step in who wouldn't otherwise. The expert opinion on this is that such a thing will happen - it is the objective of TAME as stated by the organizers.

Can Present Stem Cell Therapies Improve Vaccine Response in the Elderly?

Mesenchymal stem cell therapies fairly reliably reduce chronic inflammation for some period of time following the transplantation of cells. The cells don't survive long in the patient, and this effect is mediated by the signals they produce while present. Chronic inflammation causes many issues, including a disruption of tissue maintenance and regeneration. It contributes directly to the progression of numerous age-related conditions, including the components of frailty syndrome, but it is an open question as to the degree to which it is required to maintain the current state of those conditions. If inflammation is suppressed for an extended period of time, will there be some improvement in the patient?

The company Longeveron has been running trials in older frail people to examine the degree that benefits result from suppression of inflammation via stem cell therapies. Of interest is the latest trial announced here, in which they are looking at vaccine response. It is well known that older people have less functional immune systems, and one of the many consequences is that vaccination, such as against influenza, isn't as effective. It is interesting to speculate on the likely mechanisms by which stem cell induced reductions in inflammation might help: increased delivery of new immune cells due to enhanced native stem cell activity, or perhaps suppression or some degree of removal of malfunctioning immune cells?

Longeveron, a biopharmaceutical company that develops stem cell therapies for aging-related conditions, announced that it has received a $750,000 grant from the Maryland Technology Development Corporation (TEDCO). Longeveron will apply the funding towards its clinical trial examining the safety and efficacy of its allogeneic mesenchymal stem cell (MSCs) product to improve flu vaccine immune response in elderly patients with frailty. "Last year's flu season was one of the worst and deadliest in recent years, and seniors are typically the most vulnerable. Regenerative stem cell therapies hold great promise to bolster the immune systems of older people for greater resistance to flu."

"This is an important test of cell therapy technology and may have long term implications in vaccine strategies in older adults. Immune functional decline, or immunosenescence, is a hallmark feature of aging. Elder patients, particularly those who are frail, are at high risk for influenza and its complications. Data from our previous study indicate that aging frailty is associated with poor antibody response to, and clinical protection from, vaccination with standard dose trivalent inactivated influenza vaccine. While newer influenza vaccines have become available in recent years, MSCs represent a novel immunization strategy."

Longeveron's MSC product is derived from the bone marrow of young, healthy adult donors, and is currently being tested in a variety of indications in clinical trials, including Aging Frailty. In 2017, the company published positive Phase I and Phase 2 Aging Frailty study results in the Journals of Gerontology. Frail patients showed marked improvement in physical performance, lung function, and inflammation, with no serious adverse effects attributed to the treatment.The company also recently completed enrollment in the first phase of its flu vaccine immune-response trial.


A Commentary on Senolytic Gene Therapies to Target p16 Overexpression

This short commentary discusses the utility of Oisin Biotechnologies' initial strategy for destroying senescent cells, which is to use p16 expression as the determining sign of senescence. Oisin's implementation involves delivering dormant DNA machinery indiscriminately to all cells, and then triggering it only in cells with high levels of p16. This particular implementation is one of many possibilities in the gene therapy space, and thus various other groups are working on their own p16-based approaches as senolytic development as a treatment for aging grows in funding and popularity.

It isn't just senescence and aging in which this is a topic of interest, of course. There is a strong overlap with cancer, and the search for ways to selectively destroy the most aggressive cancerous cells. In many of these forms of aberrant cell the mechanisms of senescence are broken in some way. These cells have at least some of the chemical signatures of senescence, but fail to shut down and cease replication. Thus targeting expression of senescence-associated genes may work fairly well against cancer as well as the contribution of cellular senescence to aging - something that Oisin Biotechnologies is also working on.

p16Ink4a (p16) is an important tumor suppressor which is upregulated in senescent cells and in aged tissues. p16 acts as an inhibitor of the interaction between Cyclin-Dependent Kinases (CDK) 4/6 and CyclinD1 leading to the activation of retinoblastoma protein (RB). Consequently, active RB interferes with the translocation of E2F1 into the nucleus and arrests cells in the G1-S phase of the cell cycle. In cancer cells with mutations in RB or CDK4/6, p16 is normally overexpressed but unable to induce cell cycle arrest. p16-overexpressing cancer cells are found in different types of carcinomas and are considered highly aggressive and invasive.

Several drugs in recent years have been shown to have senolytic properties (i.e. being toxic for senescent cells) and to remove p16+ cells from a variety of tissues. Among these compounds, ABT-737 and its orally-available analogue ABT-263 target the anti-apoptotic proteins BCL-2, BCL-W and BCL-XL, considered essential pro-survival players in senescent cells. The effects of these compounds in mice almost completely overlap with a suicide gene strategy activated by the p16 promoter, thus suggesting specific targeting p16+ cells.

However, when we tested ABT-737 and ABT-263 against p16-overxpressing murine sarcomas we failed to observe any toxicity, despite p16+-cancer cells upregulating both BCL-2 and BCL-XL. These data could be interpreted in 3 ways: 1) ABT compounds are specifically active against non-proliferating p16+-cells; 2) the efficacy of ABTs requires upregulation of BCL-W, which we have recently shown being a common feature of senescent cells; 3) ABTs act independently of p16 expression levels. The latter hypothesis would represent a critical issue, as p16 is used as a major readout for the efficacy of senotherapies.

Since we have recently developed an inducible suicide gene regulated by the full p16 promoter, we have then studied whether the use of this strategy could be effective against p16+ tumors. Indeed, most p16-overexpressing cancer cells were efficiently eliminated by the activation of the suicide gene in both culture and in vivo conditions. These data suggest that p16 upregulation is maintained by active transcription, possibly mediated by emergency signaling pathways attempting to restrain cellular proliferation.

Our study supports the idea that the overexpression of oncosuppressors could be exploited for interventions against cancer. While we studied a specific context in which p16 is present in its wild-type form, this strategy could potentially work in situations of overexpression (by transcriptional regulation) of mutated forms, which is a common feature of cancer cells. On this line, similar strategies against additional oncosuppressors such as p14 and p53 could be effective.

In parallel, it will be of interest to understand whether a p16-based suicide gene therapy could be used in other contexts. Studies in transgenic mouse models have shown that elimination of p16+ cells using suicide genes can significantly delay the onset and progression of a number of age-related pathologies, eventually leading to lifespan extension. Whether a similar strategy could be used for human interventions is still matter of debate.


Does Malformed Lamin A Produce Enough Cellular Senescence to Contribute Meaningfully to the Progression of Aging?

Progeria is one of the better known accelerated aging conditions. It isn't actually accelerated aging, but rather one specific runaway form of cell damage that gives rise to general dysfunction in cells throughout the body. Since degenerative aging is also a matter of general dysfunction in cells throughout the body, there is some overlap in the observed results, even though the root causes are completely different. So progeria patients appear, superficially at least, to be prematurely aged, and die from heart disease early in life.

The cause of progeria was discovered to be a mutation in the Lamin A (LMNA) gene, resulting in a malformed protein now called progerin. This protein is an important structural component of the cell nucleus. If it doesn't function correctly, the nucleus becomes misshapen, and near all processes involving nuclear DNA maintenance and gene expression - the production of needed proteins at the right time from their genetic blueprints - cease to work correctly. The cell becomes dysfunctional. When near all cells are in this state, the prognosis for the individual is dire. Interestingly, in the years since this discovery, it has become clear that progerin is also present in small amounts in genetically normal older individuals. There is some debate over whether or not this is important in the progression of aging. Does it cause enough damage, or is it insignificant in comparison to other harmful processes?

In this context, we can consider cellular senescence, a mechanism closely connected to DNA damage, by which a small number of problem cells can cause outsized amounts of harm. Another possibility is damage to stem cells, as they are also small in number but highly influential on tissue function. Cells become senescent in response to internal damage, including that produced by progerin, and then either self-destruct or linger to secrete a potent mix of inflammatory and other signals. It is these signals, the senescence-associated secretory phenotype, that allows a comparatively small number of cells to produce comparatively large problems. It is known that senescent cells are important in many age-related conditions, particular those with a strong inflammatory component. Is generation of progerin significant as a cause of cellular senescence in normal aging, however? In this open access paper, researchers consider some of the mechanisms involved.

GATA4-dependent regulation of the secretory phenotype via MCP-1 underlies lamin A-mediated human mesenchymal stem cell aging

The LMNA gene encodes lamin and lamin C, which are major components of the nuclear lamina. Mutations in the LMNA gene have been implicated in premature aging disorders, including Hutchinson-Gilford progeria syndrome (HGPS). HGPS is caused by splicing defect and consequent generation of progerin, mutant-truncated lamin protein. Cells of HGPS patients exhibit an abnormal nuclear structure, increased DNA damage and premature senescence. In addition to the effects of progerin, accumulation of prelamin A, precursor of lamin A, induces defects in nuclear structures. ZMPSTE24 is an enzyme that produces mature lamin by cleavage of amino acids in prelamin A.

Zmpste24 knock-out mice have been widely used to study the mechanisms of aging and progeria. Depletion of Zmpste24 causes premature senescence in mice, including decreases in life span and bone density. Increased prelamin expression caused by ZMPSTE24 deficiency causes defective DNA repair. Zmpste24 knock-out mice have been extensively studied because of their impaired DNA damage response (DDR). Lamin also functions as a structural barrier to DDR. Altogether, these findings indicate that defects in the nuclear structure induced by progerin or prelamin lead to the accumulation of DNA damage, which results in accelerated aging.

It has been reported that exogenous expression of progerin in human mesenchymal stem cells (hMSCs) can impair their differentiation potential. Furthermore, production of induced pluripotent stem cells (iPSCs) from HGPS patients has revealed that the progerin expression levels are the highest in MSCs, vascular smooth muscle cells, and fibroblasts. These results indicate that MSCs are a specific target cell type of progerin-induced senescence. Like progerin, excessive accumulation of prelamin induces premature senescence in MSCs, including wrinkled nuclei. Downregulation of ZMPSTE24 in hMSCs also induces the senescence phenotype. These investigations imply that both progerin and prelamin can induce senescence in hMSCs with change in nuclear morphology.

Senescent cells secrete a group of factors that induce senescence in neighboring cells, a phenomenon termed senescence-associated secretory phenotype (SASP). The secreted inflammatory factors propagate senescence and recruit immune cells to senescent tissues by the generation of a pro-inflammatory environment. Among the factors reported to regulate the SASP, GATA4 has been recently identified as a regulator of senescence and inflammation. GATA4 is expressed during oncogene- and irradiation-induced senescence in fibroblasts in response to DNA damage. During the process of cellular senescence, GATA4 has a regulatory role in the SASP of fibroblasts. Because GATA4-dependent cellular senescence is closely associated with DDR, the role of GATA4 in other senescence models and other cell types may reveal a new mechanism.

Senescent hMSCs also induce senescence in neighboring cells. Monocyte chemoattractant protein-1 (MCP-1) secreted from senescent human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) induces premature senescence in neighboring cells. Insulin-like growth factor binding proteins are also produced by senescent hMSCs, and they trigger senescence in adjacent normal cells. These studies investigated the mechanisms of the SASP by inducing senescence in hMSCs through prolonged passaging. However, cellular senescence of MSCs can be regulated by various factors other than passaging. In our previous report, we have demonstrated that depletion of ZMPSTE24 and introduction of progerin induce premature senescence in hUCB-MSCs. It remains to be determined whether defective lamin triggers paracrine senescence via inflammatory factors in hMSCs.

In this study, we identified that paracrine senescence is triggered in senescent hMSCs with abnormal nuclear structures by increasing the expression of MCP-1 and that inhibition of MCP-1 decreases the SASP. Furthermore, we found that GATA4 mediates the senescence of hMSCs induced by defective lamin A. We assessed whether down-regulation of GATA4 disturbs the progerin- or prelamin A-dependent senescence phenotype. Elucidating how GATA4 regulates senescence in hMSCs with nuclear defects may aid in understanding the etiology of complex aging disorders. We show that inhibition of GATA4 expression protects hMSCs from cellular senescence, implying unique therapeutic opportunity against progeroid syndromes and physiological aging.

Progress Towards Ways to Make Old Stem Cells More Effective for Heart Repair

Stem cells in old tissues are less active than stem cells in young tissues, meaning a lesser supply of cells to maintain the tissue, and a consequent slow loss of function. The evidence to date suggest that a sizable part of this decline is a reaction to rising levels of tissue damage and the changing balance of cell signaling that results from that damage. There is certainly damage occurring to stem cells themselves, but that doesn't appear to contribute to as great a degree until very late in life. This means that it is feasible to think about ways to force stem cells to get back to work, to rejuvenate their behavior if not their level of intrinsic damage, and assess the benefits against the potential risks, such as a higher rate of cancer. The stem cell therapies of the past few decades suggest that this cancer risk is lower than was expected, that evolution has left us more wiggle room for therapeutic enhancement of stem cell activity in the old than it might have done.

Ischemic heart disease affects a majority of people, especially elderly patients. Recent studies have utilized autologous adult stem cells and progenitor cells as a treatment option to heal cardiac tissue after myocardial infarction. However, donor cells from aging patients are more likely to be in a senescent stage. Rejuvenation is required to reverse the damage levied by aging and promote a youthful phenotype. This review aims to discuss current strategies that are effective in rejuvenating aging cardiac stem cells and represent novel therapeutic methods to treat the aging heart.

Recent literature mainly focuses on three approaches that aim to reverse cardiac aging: genetic modification, pharmaceutical administration, and optimization of extracellular factors. In vitro genetic modification can be used to overexpress or knock down certain genes and allow for reversal of the aging phenotype. Pharmaceutical administration is another approach that allows for manipulation of signaling pathways related to cell proliferation and cell senescence. Since the stem cell niche can contribute to the age-related decline in stem cell function, rejuvenation strategies also include optimization of extracellular factors.

Overall, improving the intrinsic properties of aging stem cells as well as the surrounding environment allows these cells to adopt a phenotype similar to their younger counterparts. Recent studies show promising results of the ability of these techniques to rejuvenate the aging heart. However, more understanding of the combinatorial effects of these interventions and fine-tuning of these techniques is required to evaluate the translational potential of these methods. Each strategy has its own advantages and disadvantages. The success of myocardial regenerative treatment will require teamwork across various disciplines to make stem cell therapy a reliable method for cardiac repair.


Senescent T Cells as a Contributing Cause of Age-Related Autoimmunity

The more familiar autoimmune conditions, such as rheumatoid arthritis, are not all that age-related. Like cancer in young adults, they are a rare and unlucky happenstance, a form of most likely random cellular malfunction that spreads far enough to cause major problems. In later life, however, there occur a wide range of less familiar, less categorized, and comparatively poorly understood autoimmune conditions. It is an area of active research and many unknowns - look at just how recently type 4 diabetes was identified, for example.

These age-related autoimmunities arise from the chaotic failure of the immune system in late life. Cells fall into a variety of unhealthy states, malfunctioning cells dominate over useful cells, the immune system as a whole flails, producing chronic inflammation while failing at its primary tasks, and the supply of new competent immune cells diminishes dramatically. The publication here considers just one type of problem immune cell, those that have become senescent. This, fortunately, is an area in which solutions lie just around the corner. There is every reason to believe that senescent immune cells will be just as vulnerable to destruction by senolytic therapies as any other kind of senescent cell. If they are destroyed, they will cause no further harm, and the patient will be in a better position.

Immune aging (immunosenescence) is characterized by the reduced competence of acquired immunity, leading to increased susceptibility to infection as well as decreased vaccination efficiency. Recent accumulating evidence indicates that immunosenescence underlies an increased proinflammatory trait with age, including various chronic inflammatory and metabolic disorders, such as atherosclerosis and diabetes mellitus, as well as an increased risk for autoimmunity. Cellular senescence is characterized by irreversible arrest of proliferation, grossly altered gene expression, and relative resistance to apoptosis. Notably, senescent cells are often metabolically active and may become foci of host reactions in tissues by secreting various inflammatory factors. The features and consequences of cellular senescence in T cells in the immune system, however, remain elusive.

One of the most prominent changes occurring in the immune organs with age is an early involution of the thymus. The thymus is a central immune organ to support T cell development and establish T cell self-tolerance. T cell generation in the thymus sharply declines after the juvenile stage, eventually replaced almost entirely by fat tissues at later stages of life. In concordance with the decrease of T cell genesis, the peripheral naïve T cells are gradually reduced with age. Although the peripheral T cell pool is well maintained in aged individuals, the population shows a steady increase in the proportions of memory phenotype (MP) T cells.

We reported that a unique PD-1+ MP CD4+ T cell population is increased with age, now termed senescence-associated (SA-) T cells. The SA-T cells show characteristic signs and features of cellular senescence and emerge as follicular T cells in spontaneous germinal centers (GCs) that occur in aged mice. Spontaneous development of GCs is a hallmark of systemic autoimmune diseases, and among a number of changes in immune function with age is an increasing risk for autoimmunity.


Vascular Risk and Amyloid Level in the Brain Interact to Speed Cognitive Decline

In a recent paper, researchers provided evidence to suggest that the risk factors associated with cardiovascular decline with age interact with amyloid-β in the brain to accelerate cognitive decline. Having more of both produces a worse prognosis, which is not all that surprising. This is the case in many areas of aging and age-related disease: forms of damage and dysfunction interact with one another, making consequences worse than would be the case if they were independent of one another. This is one of the reasons why aging is an accelerating process, starting off slow and picking up pace ever more rapidly as the damage and dysfunction mounts. It is also one of the reasons why it is hard to predict the benefit resulting from any given approach to rejuvenation based on damage repair without actually trying it.

Cardiovascular risk factors such as raised blood pressure and excess fat tissue somewhat measure and somewhat predict the pace at which the complex machinery of blood vessels ages. In particular the failure of smooth muscle in blood vessel walls to correctly react to circumstances with dilation and contraction, the loss of capillaries delivering nutrients to energy-hungry tissues like the brain, and the progression of atherosclerosis, weakening and narrowing blood vessels with fatty plaques. There are other important processes, however, such as the routes for drainage of cerebrospinal fluid, or other ways in which amyloid-β and other metabolic waste might exit the brain.

Past research has shown that there is an equilibrium of sorts between amyloid-β in the brain and amyloid-β in the vascular system outside the brain. It is possible to drain amyloid-β from the brain to some degree by reducing it elsewhere in the body, indicating that there are processes transporting amyloid-β into the blood system, in addition to those removing it via other paths of cerebrospinal fluid drainage. This likely involves the blood-brain barrier, a part of blood vessel walls where they pass through the central nervous system, and thus is impacted by the state of vascular aging and dysfunction. This is the sort of thing one would look into if searching for the mechanisms underlying the relationship noted in the research below.

Vascular risk factors interact with amyloid-beta levels to increase age-related cognitive decline

Alzheimer's disease and cerebrovascular disease are probably the two most common causes of cognitive impairment in the elderly, but even though they often co-occur in individual patients, they are typically viewed as independent contributors. While the presence of amyloid plaques in the brain is considered a hallmark of Alzheimer's disease, some individuals with elevated amyloid levels never develop cognitive impairment. This has led to a search for additional markers beyond brain amyloid to help identify those at increased risk for cognitive decline.

The current study was designed to investigate whether the effects of increased brain amyloid and of vascular risk on cognitive decline are merely additive, reflecting a simple combination of the risks independently contributed by each factor, or synergistic, in which interaction of the two produces an even higher level of risk. The study analyzed data from 223 participants in the Harvard Aging Brain Study, an ongoing study of cognitively normal individuals ages 50 to 90 designed to improve understanding of brain changes affecting memory and cognition that occur with aging.

Upon enrollment in the study, participants receive standard imaging biomarker studies, including PET scans with a compound that reveals amyloid deposits in the brain. Assessment of vascular risk is determined by the Framingham cardiovascular risk score, which is based on factors such as hypertension, body mass index, and histories of diabetes or smoking. Participants also receive standard tests of memory, attention and language, which are repeated at annual follow-up visits.

The results showed that both elevated brain amyloid levels and higher vascular risk, as measured upon study enrollment, were associated with more rapid cognitive decline, with the most rapid changes seen in participants with elevations in both factors. The extent of the interaction between the two measures suggested a synergistic, rather than simply an additive effect.

Vascular risk factors interact with amyloid-beta levels to increase age-related cognitive decline

Identifying asymptomatic individuals at high risk of impending cognitive decline because of Alzheimer disease (AD) is crucial to the success of clinical trials aimed at preventing dementia. The advent of in vivo measures of β-amyloid (Aβ) burden highlighted a preclinical phase of AD allowing for the identification of clinically normal individuals with objective evidence of AD pathology. However, a substantial portion of individuals who are amyloid positive do not show clear evidence of cognitive decline in available longitudinal follow-up data. This is consistent with autopsy data indicating that approximately 30% of clinically normal elderly individuals have signs of elevated Aβ burden on pathological examination. These findings have prompted the search for additional biomarkers that can be used with Aβ burden to identify individuals at maximal risk of cognitive decline.

Multiple studies have demonstrated that cardiovascular risk factors, such as hypertension and hyperlipidemia (which often occur together), are also risk factors for cognitive decline and AD. Consistent with this, recent epidemiological data suggest that declining dementia incidence may be partially because of advances in the treatment of cardiovascular disease. Neuropathological studies indicate that vascular brain changes frequently co-occur with AD pathology in late-onset dementia and that vascular pathology may lower the threshold for cognitive impairment.

The goal of the present study was to examine whether a well-validated, multivariable measure of vascular risk is associated with prospective cognitive decline in a large cohort of clinically normal elderly individuals, either additively or synergistically with Aβ burden.

Are Mitochondria at the Root of Age-Related Loss of Muscle Mass and Strength?

Sarcopenia, the age-related loss of muscle mass and strength, has many possible contributing causes. There is fair evidence for most of them, from a failure to process amino acids needed for construction of new muscle mass to damaged neuromuscular junctions to loss of stem cell function. The most compelling evidence I've seem points to that stem cell dysfunction as the most significant contribution. It is certainly the case that stem cell populations decline in size and activity with age, reducing the supply of daughter cells needed to maintain tissues in good condition. Muscle stem cells are among the most studied in aging research.

The paper noted here picks through the major themes in sarcopenia, and makes the argument for linking at least some of them to age-related issues in mitochondrial function. The mitochondria are the power plants of the cell, and muscle is an energy-hungry tissue. Mitochondria can suffer forms of damage that make them harmful to their cells and the surrounding tissue; this is a significant issue in aging. More generally, all mitochondria change for the worse in old tissues, possibly in reaction to other forms of molecular damage characteristic to old tissues. They alter in shape and dynamics, and their ability to generate the energy store molecules required for cellular operations declines. How much of sarcopenia can be explained by these phenomena? Some, I think, possibly not all.

Using a targeted metabolomics approach, participants with low muscle quality presented significantly higher plasma concentrations of isoleucine and leucine, suggesting that low muscle quality is characterized by impaired transport of amino acids, especially branched chain amino acids (BCAAs), across the muscle cell membrane. The exact reasons for why amino acid uptake is reduced in older persons with low muscle quality are unknown, and further work is required to identify putative intervention/therapeutic targets.

Physiologically, amino acid uptake in muscle cells is regulated by three fundamental mechanisms: insulin signalling, BCAA (primarily leucine) blood concentration, and physical activity. Previous studies have also suggested that these 'anabolic' signals cause increased amino acid entry by dynamically enhancing muscle perfusion, and all three signals exhibit a dose-response relationship that is steeper in younger than in older persons. In other words, older persons tend to develop an 'anabolic resistance' to the three stimuli. Since muscle perfusion adaptation is mediated by endothelial reactivity, which is hampered by a pro-inflammatory state, this hypothesis can also explain why inflammation is such a strong correlate and predictor of age-related sarcopenia.

During ageing, mitochondria lose the ability to produce energy during maximal efforts but not when the energetic demand is lower. This impaired mitochondrial function could be due to inadequate perfusion or reduced muscle blood flow, resulting in lower oxygen delivery in skeletal muscle and diminished aerobic capacity. This hypothesis is interesting because it connects both energetic and anabolic deficits to the same mechanism. These results indicate that oxidative phosphorylation is progressively impaired with ageing; it is unclear whether this is because the number of mitochondria per muscle volume is diminished, the intrinsic capacity of mitochondria to generate ATP is impaired, or the availability of oxygen and nutrients at different levels of effort is compromised.

Oxidative stress and defective mitophagy (mitochondrial autophagy) are potentially involved in the decline of muscle quality with ageing and need to be considered. Dysfunctional mitochondria are characterized by reduced oxidative phosphorylation efficiency and excessive production of reactive oxygen species, which oxidize and damage macromolecules. The hypothesis that oxidative stress causes degenerative changes in tissues that are highly metabolically active, such as the brain and the muscle, has been proposed for many years. Oxidative stress may also affect satellite cells or muscle stem cell pools in skeletal muscle.

Defective mitochondrial function has been studied in regard to the neuromuscular junction (NMJ) remodelling that occurs with ageing, producing cycles of denervation-innervation that lead to motor unit loss, specifically in type II fibres, as well as muscle fibre atrophy. However, it is not clear whether these changes in the NMJ precede or follow the observed decline in muscle mass and strength that is observed with ageing. Some studies have reported altered mitochondria morphology in the NMJ that produce increased levels of oxidative stress, decreased enzymatic activity and ATP production, and impaired calcium buffering. The combination of these biological changes may have a strong negative impact on excitation-contraction coupling and eventually lead to the loss of motor units.

Overall, low muscle quality seems to be associated with (i) metabolic impairments that lead to reduced incorporation of the three major BCAAs, which are used by muscle as energy sources and are associated with muscle strength and endurance; (ii) fat accumulation in muscle tissue that ultimately leads to architectural disruption and loss of function; and (iii) high concentration of lipid species that are associated with impaired mitochondrial function and unrecycled mitochondrial proteins, potentially due to defective mitophagy or proteostasis. The extent and complexity to which these mechanisms are interconnected is unknown and should be examined in future studies. In addition, other factors that impact ageing muscle could also modulate mitochondrial function, such as (i) defects in the NMJ that leads to myofiber denervation-due to reduced capacity in motor neurons to reinnervate muscle fibres-consequently causing fibres to become atrophied; (ii) the age-associated decline in the satellite cell pool, reducing muscle regeneration after injury; and (iii) 'inflammaging', the chronic low-grade inflammation observed in older persons.


Reviewing Target Mechanisms for Exercise Mimetic Development

The open access paper noted here reviews some of the known molecular targets for the development of exercise mimetics. An exercise mimetic is a therapy that in some way triggers a fraction of the beneficial cellular response to exercise. Exercise mimetic development lags behind calorie restriction mimetic development, and both are very slow, very expensive lines of work with - so far - little to show in terms of practical, useful therapies. It remains the case that it is far easier and better to actually exercise or practice calorie restriction. Even when the first truly effective therapies are available in the clinic, and it must be said there is no real sign that this will happen before the late 2020s, they are unlikely to be as beneficial as either exercise or calorie restriction. The cellular response to stress is very complex and includes many distinct mechanisms; efforts to produce mimetic drugs tend to focus down on only a fraction of those mechanisms.

Exercise benefits young and old organisms, including increased skeletal mass, improvement in the cardiovascular system, and metabolic regulation, as well as in brain functions associated with cognition, memory, and mood. In particular, exercise promotes adult hippocampal neurogenesis and neuronal plasticity, and is associated with increased memory performance and cognition, and is considered to counter cognitive decline caused by aging and by neurodegenerative diseases.

Skeletal muscle is the most abundant tissue in the human body and the most highly activated organ in response to physical activity. Aerobic exercise affects skeletal muscle by inducing a substantial switch in composition from fast-twitching, glycolytic type IIb fibers to the more oxidative, slow-twitching type I fibers. Endurance training results in an increase in mitochondrial biogenesis and activity, vascularization, oxygen consumption and an overall improvement of aerobic capacity. Furthermore, the resulting activation of signaling pathways relevant to energy metabolism, such as the AMPK-SIRT1-PGC-1α pathway in muscle may contribute to the benefits of exercise for brain function.

The vast beneficial consequences of exercise might not be within reach of debilitated, diseased, and elderly patients. The development of compounds capable of activating cellular targets of exercise may be a new therapeutic approach. Indeed, recent research indicates that factors secreted by skeletal muscle during exercise may exert beneficial effects on brain function. This review will focus on the identified targets relevant to energy metabolism in muscle and the molecules affecting it.

An active lifestyle, despite the promising of compounds currently under study, remains the preferred choice for improving body and brain function. Indeed, the mechanisms of action of exercise mimetics still require further investigation, and the possibility of a treatment capable of replacing exercise in its entirety is remote. In order to achieve an artificial exercise regimen, potential adverse effects of prolonged treatment with exercise mimetics have to be overcome. Nonetheless, a possible use of this class of compounds could be envisioned in parallel with light training paradigms, helping to achieve a more complete exercise-induced benefit, both on brain and on peripheral functions. This is especially poignant for conditions, such as morbid obesity or neurodegenerative diseases, which may preclude exercise.


Intermittent Fasting Extends Life in Flies, But Not in the Expected Way

The open access paper noted here is an example of present day intermittent fasting research, in flies in this case, in which researchers attempt to obtain a better understanding of how this dietary adjustment influences the pace of aging. The paper caught my eye for the examination of intestinal function. If you have been following the field in recent years, you may recall that the research community believes that intestinal function is central to the aging of flies, probably much more so than is the case in mammals. We can say that flies die from intestinal dysfunction in the same way we can say that humans die of cancer and heart disease - it is the dominant feature of decline and mortality in that species.

Intermittent fasting has been shown in a variety of species to have a broadly similarly effect to the more usual form of calorie restriction approaches, at least when the overall intake of calories is still restricted in comparison to a normal diet. However, it also extends life to some degree even when overall intake of calories is not restricted. Rodents on diets that have the same caloric intake but a different scheduling of that intake exhibit differences in the pace of aging. Time spent hungry appears important, in terms of triggering the nutrient-related stress responses that keep cells healthier and less damaged. This isn't to say that the processes under the hood are identical: researchers have found considerable differences in gene expression between calorie restriction and intermittent fasting.

The time spent hungry hypothesis falters somewhat in the evidence from this study, not least because the background of historical evidence for intermittent fasting in flies is mixed. The evidence noted below suggests that intermittent fasting in flies, provided it is carried out in early life only, slows aging to benefit life span for reasons that are not the same as the usual nutrient-sensing mechanisms associated with calorie restriction. That is an interesting discovery. It may well be peculiar to flies due to the role of intestinal function in aging in those species, but I think that in general we should expect the effects of caloric intake to be more complex than simply a reflection of total calories over a period of time. That is probably true for any species.

Short-Term, Intermittent Fasting Induces Long-Lasting Gut Health and TOR-Independent Lifespan Extension

Intermittent fasting (IF), an umbrella term for diets that cycle between a period of fasting and non-fasting, has become increasingly popular as a weight loss regime (e.g., "every-other-day fasting" and the "5:2" diet). Advocates of IF argue that it shows many of the benefits seen with traditional daily energy restriction diets but with a simplified nutritional regime and increased compliance. Recent pilots and clinical trials used a fasting mimicking diet (FMD) (consisting of monthly cycles of a 5-day fast during which daily food intake was reduced to ∼50% normal caloric intake), which reduced multiple health risk factors during the post-fast recovery period, including lowered blood pressure, and reduced blood glucose and insulin-like growth factor-1 (IGF-1) levels. IF can extend lifespan in a variety of organisms, including bacteria, yeast, nematode worms, and mice. In animal models, IF has been shown to reduce the risk of developing a variety of age-related pathologies. IF is effective in preventing neurodegeneration in rodents and can attenuate cancer and cardiometabolic diseases, such as type II diabetes.

Reduced activity of nutrient-sensing pathways, with corresponding decrease in global protein translation, is implicated as an important mechanism underlying the pro-longevity effects of dietary interventions, such as dietary restriction (DR). Reduced TOR signaling is a hallmark of pro-longevity interventions, including DR, and treatment with the TOR inhibitor rapamycin extends healthy lifespan in a range of organisms. Although DR may exert some of its pro-longevity effects through reduced fecundity, DR can still extend lifespan in sterile Drosophila, implying that fecundity and lifespan can be uncoupled and that other mechanisms are also important.

Previous studies examining potential pro-longevity effects of IF in flies have produced mainly negative results. The first studies, almost 90 years ago, found that 6 hr of starvation in every 24 hr was beneficial and could extend lifespan. However, the effects of this IF regime may be strain or food medium specific, because a similar, more rigorous experiment ∼80 years later found that daily bouts of either 3 hr or 6 hr starvation throughout the adult life of the fly had neither a positive nor a negative effect on lifespan.

Here, we investigated a variety of IF regimes in flies and their effects on a range of health outcomes, including feeding behavior, gut and metabolic health, survival after stress, and lifespan. Importantly, short-term IF (the "2:5" diet) confined to early life robustly increased subsequent lifespan, particularly in females, independent of TOR signaling. Short-term IF also led to long-lasting health improvements, including increased stress resistance and a lower incidence of gut pathology that was associated with reduced bacterial abundance. Guts of flies 40 days post-IF showed a significant reduction in age-related pathologies and improved gut barrier function. We conclude that short-term IF during early life can induce long-lasting beneficial effects, with robust increase in lifespan in a TOR-independent manner, probably at least in part by preserving gut health.

Escargot Gene Knockdown Extends Life in Flies

Escargot (esg) is a gene in the Snail family of genes in fruit flies. After a certain point, it doesn't really help all that much to peer too closely at the nomenclature of genes - it is best to just accept it and move on. Reduced levels of esg modestly extend life in flies, as researchers here demonstrate. As to why this is the case, here as in so many other cases, understanding is lacking. There are a few core mechanisms of plasticity in aging, linking the operation of cellular metabolism to natural variations in longevity between individuals. These largely relate to the activation of stress responses due to environmental circumstances, such as a lack of nutrients, but an enormous number of genes and proteins can influence those core mechanisms. The map of cellular biochemistry is far from complete in all of its details, and thus sometimes all that can be done is to look at relationships and speculate.

The nervous system is a key player in maintaining homeostasis and the structural and functional integrity of living beings and, hence, in controlling aging and longevity. Given the role of the nervous system in life span control, a reasonable question would be whether genes defining the cellular specificity of neurons are also involved, in some way, in the regulation of longevity.

We have already demonstrated that several genes that encode RNA polymerase II transcription factors and that are involved in neural development affect life span in Drosophila melanogaster. Among other genes, escargot (esg) was identified as a candidate gene affecting life span in a screen of more than 1,500 insertion mutations and the insertion located downstream of esg was further confirmed to be causally associated with life span control.

The gene esg belongs to the Snail family of genes that are involved in the development of the nervous system in arthropods and chordates. In Drosophila melanogaster, Esg and other Snail proteins act to control asymmetric neuroblast division during embryogenesis; however, Esg functions are not exclusively neuronal, and it also participates in the maintenance of intestinal and male germ cells, regulates tracheal morphogenesis and development of the genital disk, and determines wing cell fate.

Here, we present new data on the role of esg in life span control. Analysis of the esg-BG01042 mutation allowed us to show that esg is involved in the regulation of life span, to varying degrees, in unmated and mated males and females. The esg-BG01042 mutation also increased locomotion, specifically during old age, indicating that the mutation slowed down aging. The increase in longevity was caused by decreased esg transcription associated with structural changes in the DNA sequences downstream of the gene.

Targets of esg encoded enzymes involved in the biosynthesis of neurotransmitters, neuropeptides, cationic transporters, and other proteins. Among others, genes involved in the defense/immune response were both up- and down-regulated. Of the genes known to be involved in life span control, at least two genes associated with increased life span, heat shock protein 26 (hsp26) and NAD-dependent methylenetetrahydrofolate dehydrogenase (Nmdmc), increased transcription.


Scaffolding Gel Spurs Regrowth of Damaged Brain Tissue

Scaffold materials are widely used in regenerative research. They often take the form of gels, making it possible to inject and shape the scaffold in damaged internal tissue. These nanoscaled materials are mixed in with signal molecules that spur cell growth. The scaffold both supports cells structurally and encourages them to correctly rebuild natural tissue, complete with its extracellular matrix. The scaffold itself is degraded by cells and replaced by that tissue - at least in the ideal circumstance.

This has been demonstrated in a variety of tissues, particularly muscle, but here researchers have managed a much more challenging feat by convincing the brain to regenerate. It remains to be seen how well this restores lost function; that is much harder to evaluate in animals than the evident fact of structural repair. Nonetheless, this seems an important development. If the central nervous system can be induced to repair itself effectively, that will open a great many doors presently closed in the extension of human life.

In a first-of-its-kind finding, a new stroke-healing gel helped regrow neurons and blood vessels in mice with stroke-damaged brains. The results suggest that such an approach may someday be a new therapy for stroke in people. The brain has a limited capacity for recovery after stroke and other diseases. Unlike some other organs in the body, such as the liver or skin, the brain does not regenerate new connections, blood vessels, or new tissue structures. Tissue that dies in the brain from stroke is absorbed, leaving a cavity, devoid of blood vessels, neurons, or axons, the thin nerve fibers that project from neurons.

To see if healthy tissue surrounding the cavity could be coaxed into healing the stroke injury, researchers engineered a gel to inject into the stroke cavity that thickens to mimic the properties of brain tissue, creating a scaffolding for new growth. The gel is infused with molecules that stimulate blood vessel growth and suppress inflammation, since inflammation results in scars and impedes regrowth of functional tissue.

After 16 weeks, stroke cavities in treated mice contained regenerated brain tissue, including new neural networks - a result that had not been seen before. The mice with new neurons showed improved motor behavior, though the exact mechanism wasn't clear. "The new axons could actually be working. Or the new tissue could be improving the performance of the surrounding, unharmed brain tissue." The gel was eventually absorbed by the body, leaving behind only new tissue.


Exercise Slows Aspects of Cardiovascular Aging, Protects Against Cell Stress

The glass half full view on exercise is that it modestly slows aging. The glass half empty view is that being sedentary accelerates age-related decline. Our species evolved in an environment that demanded considerably more physical activity than is the case in today's era of comfort, calories, and machineries of transportation. Lacking that activity, we suffer. There are any number of papers that provide evidence showing that a surprisingly large fraction of cardiovascular and muscle aging, loss of function and loss of strength, is preventable. Exercise can't stop aging, but it can certainly make a meaningful difference to quality of life along the way. If it was expensive, it might not be worth it. But it is free.

Today I'll point out a couple of open access papers that cover aspects of the effects of exercise on function and cellular biochemistry in later life. They are representative of current views on the interaction between physical activity, metabolism, and the progression of aging. As is the case for calorie restriction, one of the interesting puzzles in the matter of exercise and health is how it can manage to be beneficial and yet have a comparatively small effect on life span in our species. Short-lived species have a much more intuitive response: interventions that improve their health tend to lengthen life expectancy to a proportionate degree. Not so in humans.

In fact, I would say that one of our defining features as a species, in comparison to smaller mammals, is just how little our lifestyle affects our life span, even while producing a sizable range in health status. So in mice, just the application of calorie restriction can extend life by 40%, while in humans the overall difference in life expectancy between a terrible lifestyle and an optimal lifestyle is, at best, 15% or so. The scientific understanding of the details of aging and cellular metabolism is not yet at the point that would allow us to do more than speculate as to how this can be the case, even as the short-term benefits of exercise and calorie restriction in mice and humans look very similar.

The effect of lifelong exercise frequency on arterial stiffness

Central arterial stiffness increases with sedentary aging. While near-daily, vigorous lifelong (more than 25 years) endurance exercise training prevents arterial stiffening with aging, this rigorous routine of exercise training over a lifetime is impractical for most individuals. The aim was to examine whether a less frequent 'dose' of lifelong exercise training (4-5 sessions per week for more than 30 minutes) that is consistent with current physical activity recommendations elicits similar benefits on central arterial stiffening with aging.

A cross-sectional examination of 102 seniors (60 years and older), who had a consistent lifelong exercise history was performed. Subjects were stratified into 4 groups based on exercise frequency as an index of exercise 'dose': sedentary: fewer than 2 sessions per week; casual exercisers: 2-3 sessions per week; committed exercisers: 4-5 sessions per week; Masters athletes: 6-7 sessions per week plus regular competitions. Detailed measures of arterial stiffness and left ventricular afterload were collected.

Biological aortic age and central pulse wave velocity were younger in committed exercisers and athletes compared to sedentary seniors. TACi (total arterial compliance) was lower, while carotid β-stiffness index and Eai (effective arterial elastance) were higher in sedentary seniors compared to the other groups. There appeared to be a dose-response threshold for carotid β-stiffness index and TACi. Peripheral arterial stiffness was not significantly different among the groups. This suggest that 4-5 weekly exercise sessions over a lifetime is associated with reduced central arterial stiffness in the elderly. A less frequent dose of lifelong exercise (2-3 sessions/wk) is associated with decreased ventricular afterload and peripheral resistance, while peripheral arterial stiffness is unaffected by any dose of exercise.

Long-Term Exercise Protects against Cellular Stresses in Aged Mice

Regular exercise improves the physical capacity and reduces the risk of developing chronic and age-related diseases by improving the metabolic state, antioxidant protection, and redox regulation. Lifelong training was reported to slow down aging-associated skeletal muscle fiber atrophy and prevent the reduction in muscular strength. Notably, acute intensive exercise induces the production of reactive oxygen species (ROS) that can evoke macromolecular damage, oxidative stress, endoplasmic reticulum (ER) stress, and activation of the unfolded protein response (UPR).

On the other hand, regular exercise training results in adaptations in antioxidant defense and improves redox signaling to protect cells against stress-related diseases, thus delaying the aging processes. In addition, the UPR, which is activated by exercise in skeletal muscles, may exert protective effects against ER stress and can promote metabolic adaptation to physical activity. Long-term exercise was reported to upregulate heat shock protein (HSP) production in skeletal muscle, which would be beneficial in coping with oxidative stress, ER stress, and ER stress-related apoptosis. Nevertheless, the ability to induce HSPs in aged skeletal muscle is compromised, which may impair the exercise-mediated adaptation processes.

There is only limited information available on the association of aging and exercise training concerning oxidative stress, ER (SR) stress, UPR, and/or ER stress-related apoptosis in skeletal muscle. Our hypothesis is based on the fact that there is an age-induced disruption of redox regulation, increased redox ER stress, and ER stress-related apoptosis, and that long-term exercise can exert protective effects against these processes. We investigated the key molecular markers associated with redox state, ER stress, and apoptosis in skeletal muscle of old animals in a life-long running model and compared them to young animals. Our data demonstrated that aging induced oxidative stress and activated ER stress-related apoptosis signaling in skeletal muscle, whereas long-term wheel-running improved redox regulation, ER stress adaptation and attenuated ER stress-related apoptosis signaling. These findings suggest that life-long exercise can protect against age-related cellular stress.

Reviewing the Development of Stem Cell Therapies for Osteoarthritis

Arguably, age-related joint issues are where comparatively simple, first generation stem cell therapies have so far had their greatest and most reliable impact. To pick one example, mesenchymal stem cell therapies effectively reduce chronic inflammation for an extended period of time, achieving this result via the signals secreted by the transplanted stem cells in the comparatively short time they remain alive in the patient. Since arthritis is an inflammatory condition, and given that chronic inflammation interferes in the processes of healing, a reduction may spur some degree of increased tissue maintenance activity and repair. Reports suggest that this consequent regeneration is a lot less reliable than the reduction of inflammation, however.

Osteoarthritis (OA) is a prevalent debilitating joint disorder characterized by erosion of articular cartilage. The degradation of network of collagen and proteoglycan in OA cartilage leads to a loss in tensile strength and shear properties of cartilage. Interestingly, though OA manifests as loss of the articular cartilage, it also includes all tissues of the joint, particularly the subchondral bone. Besides aging, the increase in level of accumulation of advanced glycation end products (AGEs), oxidative stress, and senescence-related secretory phenotypes are a few reported factors associated with pathogenesis of OA.

The potential of stem cells to differentiate into osteoblasts, chondroblasts, and adipocytes, if stimulated properly, can regenerate cartilage both in vivo and in vitro. Recent progress in tissue engineering has highlighted the regenerative potential of stem cells for therapeutic purposes. The multilineage potential of stem cells, suitable scaffolds, and appropriate chondrogenic agent (chemical and mechanical stimuli) have been implicated to regenerate damaged cartilage. Mesenchymal stem cell (MSC) based therapy is also emerging as alternative to joint replacement with prostheses, due to its long-lasting effect.

MSCs derived from bone marrow (BMSCs) are capable enough to differentiate into tissues such as bone and cartilage and mobilize at an injured cartilage site in knee joints thereby assisting in cartilage regeneration in OA. In a study, the intra-articularly transplanted BMSC successfully regenerated injured cartilage in an animal model of OA and also improved osteoarthritic symptoms in humans without any major side effect even in the long-term. This study demonstrated the possibility of intra-articular injection of MSCs for the treatment of injured articular tissue including anterior cruciate ligament, meniscus, or cartilage. Therefore, if this treatment option is well-established, it may be minimally invasive procedure compared to conventional surgeries.


A Fraction of Age-Related Frailty and its Consequences are Self-Inflicted

While regular moderate exercise appears to have only modest effects on overall longevity - five years or so at most, based on the epidemiological data - it does greatly improve long term health. The same might be said of avoiding weight gain, and thereby the consequences of excess visceral fat tissue. Studies suggest that some fraction of the decline of aging is self-inflicted, in the sense of being due to a lack of suitable exercise, gain of weight, smoking, and the like. While it isn't possible to avoid growing old, more of the unpleasant portions of aging can be evaded than is thought to be the case by the public at large. Being sedentary has real consequences when it comes to health and quality of life in later years.

New research has shown that older people with very low heart disease risks also have very little frailty, raising the possibility that frailty could be prevented. The largest study of its kind found that even small reductions in risk factors helped to reduce frailty, as well as dementia, chronic pain, and other disabling conditions of old age. Many perceive frailty to be an inevitable consequence of ageing - but the study found that severe frailty was 85% less likely in those with near ideal cardiovascular risk factors.

"This study indicates that frailty and other age-related diseases could be prevented and significantly reduced in older adults. Getting our heart risk factors under control could lead to much healthier old ages. Unfortunately, the current obesity epidemic is moving the older population in the wrong direction, however our study underlines how even small reductions in risk are worthwhile." The study analysed data from more than 421,000 people aged 60-69 in both GP medical records and in the UK Biobank research study. Participants were followed up over ten years.

The researchers analysed six factors that could impact on heart health. They looked at uncontrolled high blood pressure, cholesterol and glucose levels, plus being overweight, doing little physical activity and being a current smoker. "Individuals with untreated cardiovascular disease or other common chronic diseases appear to age faster and with more frailty. In the past, we viewed ageing and these common chronic diseases as being both inevitable and unrelated to each other. Now our growing body of scientific evidence on ageing shows what we have previously considered as inevitable might be prevented or delayed through earlier and better recognition and treatment of cardiac disease."


Cerebrospinal Fluid Flow Influences Neural Stem Cell Activity

Researchers have found that a physical mechanism in the brain, the flow of cerebrospinal fluid and the shear forces generated by that flow, influences the activity of neural stem cells via a distinctive set of biochemical signals. This will in turn influence the rate of neurogenesis, the creation of new neurons and their integration into existing neural networks. This process is important in learning, neurodegeneration, and the resilience of the brain when it comes to recovery from damage.

It is worth considering this recent discovery in the context of what is already known of reduced and impeded drainage of cerebrospinal fluid with age. The system of spaces through which cerebrospinal fluid circulates is not entirely closed off from the rest of the body, and normally drainage serves to remove metabolic wastes from the brain. It is thought that loss of drainage with age is an important contributing cause of the buildup of protein aggregates found in many neurodegenerative conditions, particularly the amyloid associated with Alzheimer's disease.

More generally, the production of cerebrospinal fluid declines with age, its fluid pressure falls, and the flow characteristics both change and diminish. It is well known that neurogenesis rates also fall with aging, at least in the well explored mouse brain, and setting aside the present controversy over the existence of adult human neurogenesis. That the fluid dynamics of cerebrospinal fluid ties into this aspect of aging is perhaps an important advance in understanding, given that we are likely to see an increased focus on this part of the brain's physiology from the Alzheimer's research community in the years ahead.

Flow of cerebrospinal fluid regulates neural stem cell division

Researchers have discovered that the flow of cerebrospinal fluid is a key signal for neural stem cell renewal. Neural stem cells in the brain can divide and mature into neurons and this process plays important roles in various regions of the brain - including olfactory sense and memory. These cells are located in what is known as the neurogenic stem cell niche one of which is located at the walls of the lateral ventricles, where they are in contact with circulating cerebrospinal fluid.

The cerebrospinal fluid fills the brain and its roles are still poorly understood. This work highlights the role of this fluid as a key signal - but this time not a chemical but a physical signal. The mechanism is controlled by the ENaC molecule. This abbreviation stands for epithelial sodium (Na) channel and describes a channel protein on the cell surface through which sodium ions stream into the cell's interior. "We were able to show in an experimental model that brain stem cells are no longer able to divide in the absence of ENaC. Conversely, a stronger ENaC function promotes cell proliferation."

Further tests showed that the function of ENaC is augmented by shear forces exerted on the cells by the cerebrospinal fluid. The physical stimulation causes the channel protein to open for longer time and allow sodium ions to flow into the cell, thus stimulating division. "The results came as a big surprise, since ENaC had previously only been known for its functions in the kidneys and lungs." Pharmacological ENaC blockers are already used clinically to relieve certain types of hypertension. Now it is known that they can also influence stem cells in the brain and thus brain function.

Epithelial Sodium Channel Regulates Adult Neural Stem Cell Proliferation in a Flow-Dependent Manner

One hallmark of adult neurogenesis is its adaptability to environmental influences. Here, we uncovered the epithelial sodium channel (ENaC) as a key regulator of adult neurogenesis as its deletion in neural stem cells (NSCs) and their progeny in the murine subependymal zone (SEZ) strongly impairs their proliferation and neurogenic output in the olfactory bulb.

Importantly, alteration of fluid flow promotes proliferation of SEZ cells in an ENaC-dependent manner, eliciting sodium and calcium signals that regulate proliferation via calcium-release-activated channels and phosphorylation of ERK. Flow-induced calcium signals are restricted to NSCs in contact with the ventricular fluid, thereby providing a highly specific mechanism to regulate NSC behavior at this special interface with the cerebrospinal fluid. Thus, ENaC plays a central role in regulating adult neurogenesis, and among multiple modes of ENaC function, flow-induced changes in sodium signals are critical for NSC biology.

PCSK9, a Review of the Progress from Discovery to Therapy

PCSK9 inhibition therapies dramatically reduce cholesterol levels in the bloodstream, and seem set to take over from statins as the next generation approach to cholesterol management in the context of cardiovascular disease risk. Atherosclerosis results from the ability of a combination of damaged lipids - such as oxidized cholesterol - and overall level of lipids to overwhelm macrophage cells called in to clean up points of irritation in blood vessel walls. A feedback loop of inflammation and cell death sets in, as macrophages, filled with lipids and in the process of dying, call for further help, secreting cytokines that produce inflammation. The fatty deposits that weaken and narrow blood vessels in the later stages of atherosclerosis are composed of dead macrophages and the lipids they failed to clean up.

One way to try to slow down this runaway process of damage is to reduce the input of cholesterol. This is the basis of the success of statins in lowering cardiovascular risk, and the evidence suggests that further lowering of cholesterol levels will reduce that risk to a greater degree. This is still, however, only a stepping stone on the way to an effective and complete solution. PCSK9 inhibition doesn't halt or significantly reverse atherosclerosis, it still only slows it down somewhat. The research community must focus on different mechanisms and strategies, such as perhaps ways to make macrophages more resilient and more effective, allowing them to continue to operate in old people just as well as they do in young people. The SENS approach of removing oxidized lipids via delivery of bacterial enzymes is one example.

Unknown 15 years ago, PCSK9 (proprotein convertase subtilisin/kexin type 9) is now common parlance among scientists and clinicians interested in prevention and treatment of atherosclerotic cardiovascular disease. What makes this story so special is not its recent discovery nor the fact that it uncovered previously unknown biology but rather that these important scientific insights have been translated into an effective medical therapy in record time. Indeed, the translation of this discovery to novel therapeutic serves as one of the best examples of how genetic insights can be leveraged into intelligent target drug discovery.

Initial clues were provided by a French family with familial hypercholesterolemia (FH) in 2003. Gain-of-function mutations in PCSK9 were linked with hypercholesterolemia and ultimately uncovered a key new player in lipid metabolism. This seminal discovery led to a series of investigations that demonstrated that loss-of-function (LOF) mutations in PCSK9 associate with lifelong low cholesterol levels and marked reductions in the risk of atherosclerotic cardiovascular disease (ASCVD). The rare individuals with homozygous LOF mutations in PCSK9 (and no circulating protein) demonstrated extremely LDL cholesterol (LDL-C; ≈15 mg/dL), normal health and reproductive capacity, and no evidence of neurological or cognitive dysfunction.

This complementary set of observations has been leveraged into the most important therapy for the treatment of hypercholesterolemia and ASCVD since the introduction of statins. Indeed, the so-called PCSK9 inhibitors, fully human monoclonal antibodies that bind PCSK9, reduce LDL-C by ≈60% and risk of myocardial infarction and stroke by ≈20% after more than 2 years of treatment. Remarkably, these agents antagonizing PCSK9 action were approved by regulatory agencies spanning the globe only a decade after its discovery - although the scientific and medical communities have swiftly uncovered many facets of PCSK9 biology, there is still much to learn.


Uncovering the Senolytic Mechanism of Piperlongumine

Senolytic compounds are those capable of selectively destroying senescent cells. They are useful because the buildup of senescent cells over time is one of the root causes of aging. A number of mechanisms have been discovered by which senescent cells can be provoked into self-destruction, such as bcl-2 inhibition or interference in FOXO4-p53 interactions. These examples are fairly well understood. Other mechanisms are known but less well understood; they require more work in order to proceed on the production of improved senolytic compounds.

In some cases, however, the primary mechanism of action of a compound found to be senolytic through experimental screening isn't yet known. The open access paper noted here is an example of how to move forward in this situation: the researchers report on their efforts to characterize the mechanism underlying the ability of piperlongumine to selectively destroy senescent cells. This line of work has been ongoing for a few years now; it takes time. Given sufficiently knowledge of the mechanism, however, it is usually possible to find or develop more effective candidate drugs in this family. Piperlongumine isn't perfect, and can be improved upon.

Cellular senescence occurs when irreversible cell cycle arrest is triggered by telomere shortening or exposure to stress. Senescent cells (SCs) accumulate if they cannot be removed rapidly by the immune system due to immune dysfunction and/or a sustained, overwhelming increase in SC production. This occurs during aging or under certain pathological conditions. Under these circumstances, SCs can be detrimental and play a causal role in aging, age-related diseases, and chemotherapy- and radiotherapy-induced side effects, in part through the expression of the senescence-associated secretory phenotype.

This hypothesis is supported by recent studies demonstrating that the genetic clearance of SCs prolongs the lifespan of mice and delays the onset of several age-related diseases and disorders in both progeroid and naturally aged mice. Therefore, the pharmacological clearance of SCs with a small molecule, a senolytic agent that can selectively kill SCs, is potentially a novel anti-aging strategy and a new treatment for chemotherapy- and radiotherapy-induced side effects.

However, a major challenge facing the discovery and development of effective senolytic agents is to identify and validate more senolytic targets. Since the first senolytic was published, twelve molecular targets have been identified. These findings led to the discovery of a few senolytic agents, but the clinical application of these senolytic agents for age-related diseases and cytotoxic cancer therapy-induced side effects may be limited by agent toxicity and manufacturing challenges.

Piperlongumine (PL) is one of a few natural products identified to have the ability to selectively kill SCs. Compared to other known senolytic agents, PL has the advantage of low toxicity, an excellent PK/PD profile, and oral bioavailability. However, its molecular targets and mechanisms of action are unknown. To facilitate the development of PL and its analogues as senolytic drug candidates, it is critical to identify PL molecular targets, which can form a molecular basis for the rational design of new PL analogues.

Herein, we report the identification and validation of oxidation resistance 1 (OXR1) as a molecular target of PL in SCs. OXR1 is a cellular oxidative stress sensor that regulates the expression of a variety of antioxidant enzymes and modulates the cell cycle and apoptosis. We found that OXR1 was upregulated in SCs induced by ionizing radiation or extensive replication. PL bound to OXR1 directly and induced its degradation through the ubiquitin-proteasome system in an SC-specific manner. Knocking down OXR1 selectively induced apoptosis in SCs and sensitized the cells to oxidative stress caused by hydrogen peroxide (H2O2). These findings suggest that OXR1 is a potential senolytic target that can be exploited for the development of selective senolytic agents with improved potency and selectivity. In addition, these findings also provide new insight into the mechanism by which SCs are highly resistant to oxidative stress.


The Many Possible Influences of the Nucleolus in Aging

The open access review paper I'll point out today covers numerous areas of cellular biochemistry relevant to aging wherein the nucleolus may have a role - though as is always the case, cause and effect in relationships with other aspects of aging are hard to pin down. As one might guess, this largely relates to stress responses, quality control, and damage repair within the cell. These line items are important in the way in which the operation of cellular metabolism determines natural variations in the pace of aging between species and between individuals within species. While the nucleolus is primarily responsible for building the ribosome structures where proteins are assembled, it has been found to play a part in a wide range of other cellular activities. Evolution tends to generate systems in which any given component has many and varied functions, and everything within a cell is connected to everything else.

This is an example of the broad, dominant class of aging research that is purely investigative. Most research into the detailed mechanisms of degenerative aging is very far removed from any thought of application, and it is lucky happenstance when such an opportunity does arise. Systems very closely tied to cellular housekeeping, or responses to stress, or replication seem unlikely to result in the foundations of truly effective therapies. We can look at calorie restriction or exercise, both of which alter all of the above items quite profoundly and throughout the body, to see the plausible benefits that might be attained through manipulation of these fundamental aspect of cellular behavior. Searching for means to adjust metabolism to modestly slow aging is not a winning strategy; the expected benefits are just not large enough. We must find ways to add decades of vigorous life, not just a few few healthy years.

Nucleolar Function in Lifespan Regulation

The nucleolus is an intranuclear organelle primarily involved in ribosomal RNA (rRNA) synthesis and ribosome assembly, but also functions in the assembly of other important ribonucleoprotein particles that affect all levels of information processing. Recent evidence has highlighted novel roles of the nucleolus in major physiological functions including stress response, development, and aging. Due to its crucial role in ribosome biogenesis, the nucleolus actively determines the metabolic state of a cell. In fact, the size of the nucleolus positively correlates with rRNA synthesis, which in turn is governed by cell growth and metabolism.

The nucleolus has been regarded as a housekeeping structure mainly known for its role in ribosomal RNA production and ribosome assembly. However, accumulating evidence has revealed its functions in numerous cellular processes that control organismal physiology, thereby taking the nucleolus much beyond its conventional role in ribosome biogenesis. Indeed, the nucleolus has been implicated in a number of other important functions including signal recognition particle (SRP) assembly, pre-transfer-RNA (tRNA) maturation, RNA editing, telomerase assembly, spliceosome maturation, and genome stability maintenance, thus more generally serving as a critical control site for ribonucleoprotein maturation as well as genome architecture.

There is also growing evidence ascribing a key role for the nucleolus in aging. Since the discovery of various genes and signaling pathways that regulate lifespan, there has been a dramatic expansion in the research on understanding the biology of aging. A number of hallmarks of aging, including genomic instability, telomere attrition, epigenetic modifications, and perturbations in proteostasis have been well established. Recent literature also highlights the crosstalk of different nucleolar functions with some of these hallmarks.

The target of rapamycin (TOR) pathway is a major pathway that integrates inputs on nutrients, growth factors, energy, and stress. When food is plentiful, it promotes cell growth and suppresses recycling processes like autophagy. When food is scarce it suppresses growth and promotes autophagy. Notably, TOR inhibition extends lifespan. Active TOR signaling has also been associated with elevated rRNA transcription in multiple studies. The TOR complex stimulates rRNA synthesis in the nucleolus. As nucleolar size correlates with rRNA synthesis, the TOR signaling pathway has correspondingly been shown to regulate nucleolar size.

Ribosome biogenesis is one of the most energy demanding processes in the cell. It is estimated that almost 80% of cellular energy reserves are required for ribosome biogenesis. Major perturbations in the cell have repercussions at the level of ribosome biogenesis and conversely, factors involved in ribosome biogenesis can regulate other processes. A number of studies have highlighted the role of ribosomal factors in regulating the lifespan of an organism. Downregulation of genes encoding multiple ribosomal proteins has been shown to extend lifespan in yeast and C. elegans. Though it remains to be tested if single ribosomal protein knockdown can have lifespan benefits in vertebrates, there is evidence suggesting that this might be the case.

The highly repeated structure of the ribsosomal DNA (rDNA) locus and its high rates of transcription make it particularly vulnerable to genome instability and damage. Multiple studies have reported a link between rDNA stability and cellular aging, as well as the association of proteins involved in genome integrity transiting the nucleolus. Aging in yeast is accompanied by nucleolar enlargement and fragmentation, suggesting a mechanism of cellular aging that may be related to nucleolar structure. Concordantly a recent study reported that the premature aging disorder Hutchinson-Gilford progeria syndrome leads to nucleolar expansion and increased ribosome biogenesis. Furthermore, there is evidence suggesting an association of replication stress on rDNA loci with the aging of hematopoietic stem cells, adding more evidence to the general function of the nucleolus in genome integrity and aging.

The nucleolus also impacts other vital cellular processes like the cell cycle and the response to cellular stress. One of the major tumor suppressor proteins central to regulating cell cycle is p53. The nucleolus acts as a platform connecting a cellular stress response with cell cycle through the central tumor suppressor p53. Interestingly multiple studies have implicated p53 in aging in different organisms. The nucleolus has also been associated with regulation of cell senescence. Alterations in nucleolar morphology have been reported in aging cells. In particular, presenescent cells exhibit multiple small-sized nucleoli compared to senescent cells which possess a single enlarged nucleolus.

The perception that the nucleolus is simply the place where ribogenesis takes place has clearly evolved. We now know that it is a highly dynamic organelle that coordinates signals from growth, energy, and stress to the balanced production and assembly of multiple ribonucleoprotein particles and the maintenance of genome integrity. This has ramifications for essentially all levels of molecular organization from genome architecture, RNA metabolism, protein synthesis and quality control to metabolism.

The Damage Done by a Lack of Exercise, and Digging Yourself Out of the Hole

How much harm is done - and how quickly - by failing to maintain an exercise program? How long does it take to reverse those consequences? No-one has the final answer to those questions, firm numbers derived from the way in which the human body functions. We can look at the results of studies such as this one with some interest, however. We might compare this with studies of weight and mortality, in which the evidence suggests that lasting harm is done by carrying excess fat tissue over years, even if lost later.

By analyzing reported physical activity levels over time in more than 11,000 American adults, researchers conclude that increasing physical activity to recommended levels over as few as six years in middle age is associated with a significantly decreased risk of heart failure. The same analysis found that as little as six years without physical activity in middle age was linked to an increased risk of the disorder. "In everyday terms our findings suggest that consistently participating in the recommended 150 minutes of moderate to vigorous activity each week, such as brisk walking or biking, in middle age may be enough to reduce your heart failure risk by 31 percent. Additionally, going from no exercise to recommended activity levels over six years in middle age may reduce heart failure risk by 23 percent."

The researchers caution that their study was observational, meaning the results can't and don't show a direct cause-and-effect link between exercise and heart failure. But the trends observed in data gathered on middle-aged adults suggest that it may never be too late to reduce the risk of heart failure with moderate exercise. "Unlike other heart disease risk factors like high blood pressure or high cholesterol, we don't have specifically effective drugs to prevent heart failure, so we need to identify and verify effective strategies for prevention and emphasize these to the public." There are drugs used to treat heart failure, such as beta blockers and ACE inhibitors, but they are essentially "secondary" prevention drugs, working to reduce the heart's workload after dysfunction is already there.

The researchers used data already gathered from 11,351 participants in the long term Atherosclerosis Risk in Communities (ARIC) study, recruited from 1987 to 1989. The participants' average age was 60, and 57 percent were women. Participants were monitored annually for an average of 19 years for cardiovascular disease events such as heart attack, stroke, and heart failure using telephone interviews, hospital records and death certificates. Over the course of the study there were 1,693 hospitalizations and 57 deaths due to heart failure.

In addition to those measures, at the first and third ARIC study visits (six years apart), each participant filled out a questionnaire, which asked them to evaluate their physical activity levels, which were then categorized as poor, intermediate or "recommended," in alignment with guidelines issued by the American Heart Association. The "recommended" amount is at least 75 minutes per week of vigorous intensity or at least 150 minutes per week of moderate intensity exercise. One to 74 minutes per week of vigorous intensity or one to 149 minutes per week of moderate exercise per week counted as intermediate level activity. And physical activity qualified as "poor" if there was no exercise at all.

Heart failure risk decreased by about 12 percent in the 2,702 participants who increased their physical activity category from poor to intermediate or recommended, or from intermediate to recommended, compared with those with consistently poor or intermediate activity ratings. Conversely, heart failure risk increased by 18 percent in the 2,530 participants who reported decreased physical activity from visit one to visit three, compared with those with consistently recommended or intermediate activity levels.


A Review of Growth Hormone in Aging

The author of this open access review of the study of growth hormone in aging is one of the eminent experts in this part of the field, noted for work on various loss of function mutant mice, lacking either functional growth hormone or functional growth hormone receptor genes. The current record for mouse longevity is held by a growth hormone knockout variant: these mice wouldn't survive in the wild, as they are small and vulnerable to cold, but they live 60-70% longer than their unmodified peers in the laboratory.

It is well documented that circulating levels of GH decline with age in various mammalian species, including humans, domestic dogs, and laboratory rodents. Yet in laboratory mice, disruption of growth hormone (GH) signaling leads to a remarkable extension of longevity. These findings were hard to interpret and were originally received with some skepticism because they implied that normal actions of a hormone have significant 'costs' in terms of longevity, and that a gross defect in the functioning of the endocrine system can have striking benefits for healthy survival. However, the evidence that absence of GH signaling extends longevity of mice is strong, reproducible, and now generally accepted.

Several aspects of the findings in GH-deficient and GH-resistant mice deserve particular emphasis. First, the significant extension of longevity in these animals is reproducible and not limited to a particular laboratory, diet, or genetic background. Second, lifespan is extended in both females and males. Third, extension of longevity is associated with a similarly striking extension of healthspan. Fourth, the magnitude of the increase in longevity exceeds the effects of most genetic, pharmacological, or dietary interventions that have anti-aging effects in mice.

A recent study examined longevity of mice lacking both GH and functional GH receptors. While these tiny 'double mutants' were remarkably long-lived compared to their normal siblings, they did not live significantly longer than mice lacking only GH or only GH receptors. In females, survival curves of GH-deficient Ames dwarf, GH-resistant GHRKO, and 'double mutant' (df/KO) animals were nearly identical.

The importance of GH signaling in the control of murine lifespan is further emphasized by the evidence that disruption of signaling events 'downstream' from GH and its receptor also extends longevity. Early findings of extended longevity of female mice heterozygous for the deletion of IGF-1 receptor were confirmed and extended in further studies. Major increase of longevity was seen in mice in which amount of bioavailable IGF-1 was reduced at the tissue level by germline or adult disruption of the gene coding for pregnancy associated plasma protein A, an enzyme degrading IGF-1 binding protein. Significant and reproducible extension of longevity was also produced by pharmacological suppression of the activity of mechanistic target of rapamycin, a kinase regulated by GH and IGF1.

Importantly, conclusions concerning pro-aging effects of normal or elevated GH based on studies in mutant, gene knockout, transgenic, or drug treated mice appear to apply to genetically normal mice and to other mammalian species. Multiple studies reported negative association of adult body size (a strongly GH- and IGF-1-dependent trait) with longevity in comparisons of different mouse strains, selected lines, and individual animals.


Is Lipid Level or Inflammation the Critical Factor for Cardiovascular Disease Risk?

No orthodoxy lacks accompanying heretics; it often seems that science is a business of proceeding abruptly and messily from one steady state consensus to another via the mechanism of heresy. It is of course worth bearing in mind that most heretics do turn out to be wrong, and are consequently forgotten by all but the most painstaking of scientific historians. In the paper I'll point out today, the orthodoxy of blood lipid levels as a cause of cardiovascular disease is challenged. The heresy is to suggest that it isn't the lipids at all, but all down to a matter of chronic inflammation.

This is a tough topic to arbitrate, because raised lipids, such as cholesterol, and raised inflammation go hand in hand. Dietary approaches to tackling cholesterol levels are minimally effective in the grand scheme of things, as dietary content is only a small factor in the lipid content of blood, but they also, inconveniently, tend to move the needle on inflammation as well. The calorie content of the diet, considered over the long-term, is linked to lipids and inflammation in equal measures via the amount of visceral fat tissue an individual carries. Therapies that are available and widely used to reduce blood cholesterol, such as statins, are shown to have anti-inflammatory effects. Therapies under development, such as delivery of the APOA1 protein that makes up the HDL particles responsible for dragging cholesterol out of vulnerable cells and transporting it to the liver, also have significant anti-inflammatory effects. You can probably see the challenge.

On the one hand, it doesn't seem completely unreasonable to mount the argument that lipid levels are a smokescreen, and we should be caring about chronic inflammation. We know that chronic inflammation is very damaging, and contributes to the progression of all of the common age-related diseases. When it comes to cardiovascular disease, and particularly atherosclerosis, it seems hard to write off a role for lipid levels in blood, however. Atherosclerosis is caused by oxidized lipids that overwhelm the cells sent to clean them up when they irritate blood vessel walls; the fatty deposits that narrow blood vessels are made up of lipids and dead cells. More lipids means more overwhelmed cells. Lower lipid levels means fewer oxidized lipids. But does that simple calculus hold up when looked at in detail? To answer that question, we need more data on highly effective therapies that are either anti-lipid or anti-inflammatory, but not both.

Inflammation, not Cholesterol, Is a Cause of Chronic Disease

According to the 'cholesterol hypothesis', high blood cholesterol is a major risk factor, while lowering cholesterol levels can reduce risk. Dyslipidaemias (i.e., hypercholesterolaemia or hyperlipidaemia) are abnormalities of lipid metabolism characterised by increased circulating levels of serum total cholesterol, LDL cholesterol, triglycerides, and decreased levels of serum HDL cholesterol. High levels of LDL cholesterol and non-HDL cholesterol have been associated with cardiovascular risk, while other cholesterol-related serum markers, such as the small dense LDL cholesterol, lipoprotein(a), and HDL particle measurements, have been proposed as additional significant biomarkers for cardiovascular disease (CVD) risk factors to add to the standard lipid profile.

HDL cholesterol has been considered as the atheroprotective 'good' cholesterol because of its strong inverse correlation with the progression of CVD; however, it is the functionality of HDL cholesterol, rather than its concentration that is more important for the preventative qualities of HDL cholesterol in CVD. In general, dyslipidaemias have been ranked as significant modifiable risk factors contributing to prevalence and severity of several chronic diseases including aging, hypertension, diabetes, and CVD. High serum levels of these lipids have been associated with an increased risk of developing atherosclerosis.

Furthermore, dyslipidaemias have been characterised by several studies not only as a risk factor but as a "well-established and prominent cause" of cardiovascular morbidity and mortality worldwide. Even though such an extrapolation is not adequate, it was, however, not surprising that this was made, because since the term arteriosclerosis was first introduced by pioneering pathologists of the 19th century, it has long been believed that atherosclerosis merely involved the passive accumulation of cholesterol into the arterial walls for the formation of foam cells. This process was considered the hallmark of atherosclerotic lesions and subsequent CVD.

Moreover, one-sided interpretations of several epidemiological studies, such as the Seven Countries Study (SCS), have highlighted outcomes that mostly concerned correlations between saturated fat intake, fasting blood cholesterol concentrations, and coronary heart disease mortality. Such epidemiological correlations between dyslipidaemias and atherosclerosis led to the characterisation of atherosclerosis as primarily a lipid disorder, and the "lipid hypothesis" was formed, which would dominate thinking for much of the 20th century.

On the other hand, since cholesterol is an essential biomolecule for the normal function of all our cells, an emerging question has recently surfaced: "how much do we need to lower the levels of cholesterol"? Furthermore, given the fact that cholesterol plays a crucial role in several of our cellular and tissue mechanisms, it is not surprising that there are several consequences due to the aggressive reduction of cholesterol levels in the body. Moreover, recent systematic reviews and meta-analyses have started to question the validity of the lipid hypothesis, as there is lack of an association or an inverse association between LDL cholesterol and both all-cause and CVD mortality in the elderly.

The principles of the Mediterranean diet and relevant data linked to the examples of people living in the five blue zones demonstrate that the key to longevity and the prevention of chronic disease development is not the reduction of dietary or serum cholesterol but the control of systemic inflammation. In this review, we present all the relevant data that supports the view that it is inflammation induced by several factors, such as platelet-activating factor (PAF), that leads to the onset of cardiovascular diseases (CVD) rather than serum cholesterol. The key to reducing the incidence of CVD is to control the activities of PAF and other inflammatory mediators via diet, exercise, and healthy lifestyle choices.

Alcor Receives $5 Million Donation

Today's good news is that the Alcor Life Extension Foundation, one of the two oldest US cryonics providers, has received a $5 million donation. Like a number of recent donations in our broader community, this originates from an individual who has done well in the growth of cryptocurrencies. I think that this philanthropy is a sign of things to come; these newly wealthy individuals are, on balance, younger and less set in their ways than those who come to wealth via the slower and more traditional means. They will be, accordingly, more adventurous, more disruptive, more supportive of causes that have a high utility but are not yet mainstream. This is all to the good, I feel.

This donation is an enormous sum for the non-profit cryonics community - it is a significant fraction of the existing Alcor assets, near all of which are locked up to support the long-term commitments of providing for its members. Cryonics is just as important to the cause of minimizing human death as the forms of medical biotechnology more usually featured here at Fight Aging! Sadly, it is also far worse off when it comes to the available resources, particular in the very necessary endeavor of research and development, to improve the state of the art, and produce a viable, self-sustaining industry based on reversible low-temperature storage of tissues. I would like to see this state of affairs change for the better, and this donation is a sizable first step on that road.

I am delighted to announce that Alcor has received a stunning $5,000,000 contribution to fund cryonics research. Alcor member Brad Armstrong (A-3000), came to visit Alcor in November 2016. After a tour and long and fascinating chat, before he left I suggested that he finally sit down and sign the membership paperwork. We would provide the witnesses and the Notary Public. 90 minutes later, Brad was done and handed us a check, making him a member. (See? It's not as difficult as you think.)

Fast forward to April 2018. Brad's assistant called to say that Brad wanted to make a major contribution to Alcor for the purposes of cryonics research. When I called Brad, I was immediately reminded that he is a down-to-earth, easygoing fellow who wants cryonics to work and is eager to fund what he knows matters. Brad is an enthusiast of cryptocurrencies and an admirer of Hal Finney - the first recipient and early developer of Bitcoin - and an Alcor member cryopreserved in August 2014. The $5 million research contribution is being held in the name of the "Hal Finney Cryonics Research Fund".

On behalf of Alcor and the cryonics effort in general, I want to say thank you. But how can I possibly express those thanks adequately? With a gift of this magnitude comes the responsibility of managing and spending it wisely for maximum impact. Until the Alcor board and Research Group determine how best to hold and use this funding, I have moved it from Alcor's bank account into a money market fund. Stay tuned as we determine how to use this remarkable influx of funding to boost Alcor's cryonics research.


Is the Architecture of the Nuclear Envelope Fundamental to the Evolution of Aging?

Hydra are functionally immortal, given a suitably static environment. They exhibit continual proficient regeneration, and their mortality risk is low and constant over time. As a species they appear near unique in this. Why is aging and imperfect regeneration almost universal among species? One explanation is that environmental change gives aging species an advantage: non-aging species can certain emerge in eras of comparative environmental stability, but will be out-competed when the environment shifts. Other explanations involve the more complex structure in higher species, particularly in the central nervous system, where data must be stored as lasting molecular and cellular structures. Long-term persistence of fine cellular structure and proficient, continual regeneration don't go well together.

This study looks at the complexity and structure of the nuclear envelope inside cells as a possible dividing line between the few immortal species such as hydra and all of the others. The authors propose that increased complexity of the nuclear structure, and thus its greater vulnerability to certain kinds of molecular damage known to be associated with aging, limits the degree to which longevity and highly proficient regeneration can evolve - though I think that this is certainly something that could be argued either way, and at length.

The freshwater polyp Hydra represents a rare case of an animal with extreme longevity. It demonstrates unlimited clonal growth with no detectable signs of senescence, such as age-dependent increase in mortality or decrease in fertility, and thus is considered as non-senescent. Hydra body is made of cells of three lineages, originating from unipotent ectodermal and endodermal epithelial stem cells, and from multipotent interstitial stem cells. In contrast to most other animals, stem cells in Hydra indefinitely maintain their self-renewal capacity, thus sustaining non-senescence and everlasting asexual growth.

While unlimited self-renewal capacity of the stem cells is long recognized fundamental for Hydra's non-senescence, the underlying molecular mechanisms remain poorly understood. So far, the transcriptional factor FoxO was found as critical regulator of Hydra stem cell homeostasis and longevity, supporting the view that components of the insulin/insulin-like growth factor signaling pathways govern lifespan throughout the animal kingdom. Several other transcriptional factors are supposed to contribute to the non-aging of Hydra. However, the putative effector molecules downstream from these transcriptional factors that might contribute to the sustained stem-cell activity and non-senescence in Hydra remain unclear.

Studies in bilaterian animals propose proteins of the Lamin family to be the major effector molecules involved in the age-related cellular senescence and, hence, in the genetic control of ageing and lifespan. These highly conserved intermediate filament proteins form a complex network at the inner nuclear membrane, arrange the nuclear architecture and orchestrate multiple nuclear processes, such as DNA replication and repair, chromatin condensation, and transcription. Importantly, bilaterian cells are highly sensitive to the nuclear lamina disturbances. Decline in the expression level of Lamin B1 and increase of an aberrant Prelamin A isoform are associated with the age-dependent alterations in the nuclear lamina morphology and chromatin organization observed upon physiological ageing in mammals and invertebrates.

A homologue of vertebrate lamin B genes has been identified in Hydra, yet no efforts have been reported addressing the role of Lamin in cnidarian longevity. Here we present detailed analysis of the single Hydra lamin gene (hyLMN), its expression pattern, and distribution and function of its protein product (HyLMN). We demonstrate that proliferation of stem cells in Hydra is robust against the disturbance of Lamin expression and localization. While Lamin is indispensable for Hydra, the stem cells tolerate overexpression, downregulation, and mislocalization of Lamin, and disturbances in the nuclear envelope structure. This extraordinary robustness may underlie the indefinite self-renewal capacity of stem cells and the non-senescence of Hydra. A relatively low complexity of the nuclear envelope architecture might allow for the observed extreme lifespans of Hydra, while an increasing complexity of the nuclear architecture in bilaterians resulted in restricted lifespans.


Considering Mitochondria and Neurodegeneration

Since mitochondria seem to be the dominant theme this week, today I thought I'd point out a couple of recent open access papers that focus on the role of mitochondrial function (and dysfunction) in the neurodegeneration that accompanies aging. Every cell bears a swarm of mitochondria, the descendants of ancient symbiotic bacteria. Even though mitochondria long ago evolved into integrated cellular components, they still behave very much like bacteria in many ways. They multiply through division, and can fuse together and swap component parts, pieces of the molecular machinery necessary to their function. They also contain their own DNA, distinct from that of the cell nucleus.

The primary role of mitochondria is to undertake the energetic process of packaging chemical energy store molecules to power cellular operations. This is of particularly importance to energy-hungry tissues such as the brain, and why mitochondrial dysfunction with advancing age is thought to be especially relevant to neurodegenerative conditions. The evidence for this is more clear or less clear depending on which condition is discussed. In Parkinson's disease, for example, it is very evident that mitochondrial function is central to the characteristic loss of specialized neurons that drives the condition. For Alzheimer's disease, on the other hand, it is a real challenge to talk about the degree to which the numerous involved mechanisms are more or less important than one another. There is a lot of conflicting evidence.

The decline of mitochondrial function with age appears to have several distinct causes, not all of which are fully understood. Quality control mechanisms responsible for destroying errant and worn out mitochondria become less effective in later life. Some forms of mitochondrial DNA damage can produce mitochondria that are more resilient to quality control or more able to replicate than their peers, and they can take over cells to make them malfunction and cause harm. But aside from this, all mitochondria change profoundly in activity and structure in older individuals, and this may be a broad reaction to rising levels of molecular damage or other changes in signaling and cell behavior, above and beyond issues caused by failing quality control.

Brain Mitochondria, Aging, and Parkinson's Disease

High energy requirements tissues such as the brain are highly dependent on mitochondria. Mitochondria are intracellular organelles deriving and storing energy through the respiratory chain by oxidative phosphorylation. In a single neuron, hundreds to thousands of mitochondria are contained. Non-inherited mitochondrial DNA (mtDNA) mutations are called somatic mutations and appear over time. Mutated mtDNA replication is better when compared to wild-type mtDNA, which facilitates its clonal expansion. Once mutated mtDNA reaches at least 60%, the cell will have deficient respiration and will accumulate additional mtDNA mutations until cell death.

Somatic mtDNA mutations are important in aging and disease such as Parkinson's disease (PD). PD results mostly from the loss of dopaminergic neurons in the substantia nigra (SN). SN dopaminergic neurons are lost in an age and mitochondrial dysfunction related way. When compared to other neurons, SN dopaminergic neurons have more mtDNA deletions, where the load of mtDNA mutations parallels the deficiency of the respiratory chain.

Aging, at the cell level, is an increasingly incapacity to recycle organelles and macromolecules. Mitochondria DNA is very vulnerable. The aging process is tightly linked to mtDNA deletions and point mutations and to reactive oxygen species (ROS). Additionally, mtDNA deletions and point mutations accumulate over time. This leads to energetics impairment, increased ROS production, mtDNA lesions, and the decline of mitochondrial respiration.

Mitochondrial Chaperones in the Brain: Safeguarding Brain Health and Metabolism?

The brain orchestrates organ function and regulates whole body metabolism by the concerted action of neurons and glia cells in the central nervous system. To do so, the brain has tremendously high energy consumption and relies mainly on glucose utilization and mitochondrial function in order to exert its function. As a consequence of high rate metabolism, mitochondria in the brain accumulate errors over time, such as mitochondrial DNA (mtDNA) mutations, reactive oxygen species, and misfolded and aggregated proteins. Thus, mitochondria need to employ specific mechanisms to avoid or ameliorate the rise of damaged proteins that contribute to aberrant mitochondrial function and oxidative stress.

To maintain mitochondria homeostasis (mitostasis), cells evolved molecular chaperones that shuttle, refold, or in coordination with proteolytic systems, help to maintain a low steady-state level of misfolded and aggregated proteins. Their importance is exemplified by the occurrence of various brain diseases which exhibit reduced action of chaperones. Chaperone loss (of expression and/or function) has been observed during aging, metabolic diseases such as type 2 diabetes and in neurodegenerative diseases such as Alzheimer's, Parkinson's or even Huntington's diseases, where the accumulation of damage proteins is evidenced. Within this perspective, we propose that proper brain function is maintained by the joint action of mitochondrial chaperones to ensure and maintain mitostasis contributing to brain health, and that upon failure, alter brain function which can cause metabolic diseases.

XPO1 as a Novel Target for Therapies to Enhance Autophagy

Autophagy is the name given to a collection of cellular housekeeping processes that recycle damaged and unwanted proteins and structures inside a cell. Most of the means of slowing aging demonstrated in laboratory species involve increased autophagy: it is an important response to any form of stress likely to result in more damage inside the cells. The less damage there is, the better off the cells. This in turn can leads to a longer, healthier life span to some degree. It is also worthy of note that autophagy declines with age, and this is though important in a range of age-related conditions.

Autophagy enhancement therapies have been on the research community agenda for a long time now. There have been scores of papers published on this topic in the last decade alone, even putting to one side the point that all calorie restriction mimetic development is likely based on increased levels of autophagy somewhere under the hood. Unfortunately, means of directly enhancing autophagy have not as yet made it out of the lab; there has been very little progress towards the clinic. This is worth bearing in mind when reading publicity materials of the sort presented here. It is little different in tone from similar items published many years ago, and which subsequently went nowhere.

The process of autophagy involves the rounding up of misfolded proteins and obsolete organelles within a cell into vesicles called autophagosomes. The autophagosomes then fuse with a lysosome, an enzyme-containing organelle that breaks down those cellular macromolecules and converts it into components the cell can re-use. Researchers wanted to see if they could increase autophagy by manipulating a transcription factor (a protein that turns gene expression on and off) that regulates autophagic activity. In order for the transcription factor to switch autophagic activity on, it needs to be localized in the nucleus of a cell. So the team screened for genes that enhance the level of the autophagy transcription factor, known as TFEB, within nuclei.

Using the nematode C. elegans, the screen found that reducing the expression of a protein called XPO1, which transports proteins out of the nucleus, leads to nuclear accumulation of the nematode version of TFEB. That accumulation was associated with an increase in markers of autophagy, including increased autophagosome, autolysosomes as well as increased lysosome biogenesis. There was also a marked increase in lifespan among the treated nematodes of between about 15 and 45 percent.

The next step was to see if there were drugs that could mimic the effect of the gene inhibition used in the screening experiment. The researchers found that selective inhibitors of nuclear export (SINE), originally developed to inhibit XPO1 to treat cancers, had a similar effect - increasing markers of autophagy and significantly increasing lifespan in nematodes. The researchers then tested SINE on a genetically modified fruit fly that serves as a model organism for the neurodegenerative disease ALS. Those experiments showed a small but significant increase in the lifespans of the treated flies.

As a final step, the researchers set out to see if XPO1 inhibition had similar effects on autophagy in human cells as it had in the nematodes. After treating a culture of human HeLa cells with SINE, the researchers found that, indeed, TFEB concentrations in nuclei increased, as did markers of autophagic activity and lysosomal biogenesis. "Our study tells us that the regulation of the intracellular partitioning of TFEB is conserved from nematodes to humans and that SINE could stimulate autophagy in humans. SINE have been recently shown in clinical trials for cancer to be tolerated, so the potential for using SINE to treat other age-related diseases is there."


A View of Aging Centered Around Mutation and Senescence

Many researchers see stochastic mutational damage to nuclear DNA as an important mechanism in aging, above and beyond its contribution to cancer risk. The challenge has always been that there don't seem to be enough mutations to explain significant harm, if the harm remains restricted to only the cell in which the mutation occurs. One way to explain how DNA damage causes more general issues is through clonal expansion of detrimental mutations that occur in stem and progenitor cells. Another possible explanation, presently being energetically explored by the research community, is that DNA damage can cause cellular senescence. In this case, just a few senescent cells can cause outsized amounts of harm in surrounding tissue through the potent mix of signals they secrete: generating inflammation, remodeling the extracellular matrix, changing the behavior of other cells for the worse, and so on. We'll be seeing a great many papers like this one in the years ahead, I think.

During an organism's lifetime, cells are constantly exposed to exogenous and endogenous stressful agents. Cells can cope with these stressors by various response mechanisms, or in case of irreversible damage, programmed cell death (apoptosis), or permanent cell-cycle arrest (cellular senescence). Cellular senescence is characterized by a halt in cellular replication, accompanied by a specific molecular phenotype. This phenotype can be the result of a few factors, such as accumulation of DNA damage, telomere attrition, and various epigenetic alterations.

Cellular senescence is one of the cellular pathways contributing to organismal aging. Senescent cells can accumulate in tissues and organs and can ultimately result in tissue lesions that will cause organ dysfunction, such as through the senescence-associated secretory phenotype (SASP). Age-related accumulation of DNA damage has been studied thoroughly, showing correlation between age and damage levels or mutation frequency. In the presence of DNA lesions or abnormalities, the DNA damage response (DDR) is activated and can eventually lead to cell cycle arrest. In older organisms, accumulation of DNA damage and loss of regenerative potential consequently increase the number of senescent cells, leading to aging cells, tissues, organs, and inevitable death.

The accumulation of genomic abnormalities is influenced by the quality of the repair pathways, which may also decline with age. Researchers studied age-related DNA damage in peripheral blood cells using single nucleotide polymorphism (SNP) microarray data from over 50,000 individuals. The frequency of detectable genomic abnormalities was low (less than 0.5%) at birth and rose to 2-3% in 50-year-old donors. Peripheral blood cells were also studied using whole-exome sequencing data from DNA of 17,182 individuals lacking hematologic phenotypes. Somatic mutations were rare in young donors (~40 years old) but became more frequent with age. Furthermore, while studying subjects at 70-79 years, compared with 90-108 years, mutation frequency rose from 9.5 to 18.4%, respectively.

In conclusion, the connection between DNA damage and aging is emphasized by the secretion of senescence-associated proteins during cellular senescence, a phenotype which is activated by DNA damage and is common for both human and mice. Though much progress has been achieved, full understanding of these mechanisms has still a long way to go.


Reduced C/EBPβ-LIP Expression Modestly Slows Aging in Mice

There is an unbounded amount of research work that might be performed to investigate methods of modestly slowing aging in mice. Doing no more than exploring the surrounding biochemistry related to mTOR might be enough to occupy most of the researchers capable of this work for a decade. The open access paper I'll point out today is an example of the type: the authors picked one of the scores of proteins identified as having a closer relationship to mTOR and its biochemistry, and spent several person-years of time and funding learning something about its role.This type of project could easily be multiplied a hundredfold, across dozens of teams, and that would still capture only a fraction of the state space to be explored. Cells are complicated.

The research community will explore all of that state space in the fullness of time. This activity isn't, however, a cost-effective path towards meaningful therapies that might address aging in humans. That isn't even the goal of this research, though it is a useful flag to wave from time to time when seeking funding. The primary goal is to map all of mammalian metabolism, to fully understand its operation - knowledge is the motivation of pure science, not application of knowledge. Whenever researchers state in public that human life extension is only a distant prospect, they are thinking in terms of the time taken to gather a fairly complete understanding of cellular metabolism, and then on top of that the time taken to build a new metabolism that functions more efficiently and ages less rapidly.

This is why I am much in favor of the SENS rejuvenation research approach to aging. The strategy there is to keep the metabolism we have, the one we don't fully understand, but that nonetheless works well enough while we are young, and periodically repair the known forms of root cause damage that make it run awry to produce degenerative aging. This way of looking at the problem bypasses the need to fully understand cellular metabolism, and even bypasses the need to fully understand exactly how the root cause damage produces aging. Thus a much smaller set of challenges in this line of work relate to planning, building, and executing successful repair therapies, while disrupting cellular biochemistry as little as possible. Via this path, it is possible to talk about significantly turning back aging within our lifetimes.

Mutant mice hold back the years

Biologists have created mice that live longer and appear to age more slowly than ordinary mice. In previous work, researchers developed mice with a mutation that reduces the animals' production of a protein called C/EBPβ-LIP. This mutation conferred metabolic benefits similar to those achieved by limiting calorie intake, which is known to extend lifespan in some animals.

The team's new experiments show that female mice with the mutation lived approximately 10% longer than ordinary mice, and were less susceptible to cancer. As females aged, those with the mutation gained less weight and maintained better overall motor skills. Both male and female mice with reduced C/EBPβ-LIP were more resistant to age-related changes in the immune and metabolic systems, compared with control animals.

Reduced expression of C/EBPβ-LIP extends health- and lifespan in mice

Ageing is associated with physical decline and the development of age-related diseases such as metabolic disorders and cancer. Few conditions are known that attenuate the adverse effects of ageing, including calorie restriction (CR) and reduced signalling through the mechanistic target of rapamycin complex 1 (mTORC1) pathway. Synthesis of the metabolic transcription factor C/EBPβ-LIP is stimulated by mTORC1, which critically depends on a short upstream open reading frame (uORF) in the Cebpb-mRNA.

Here we describe that reduced C/EBPβ-LIP expression due to genetic ablation of the uORF delays the development of age-associated phenotypes in mice. Moreover, female mice engineered in this way display an extended lifespan. Since LIP levels increase upon aging in wild type mice, our data reveal an important role for C/EBPβ in the aging process and suggest that restriction of LIP expression sustains health and fitness. Thus, therapeutic strategies targeting C/EBPβ-LIP may offer new possibilities to treat age-related diseases and to prolong healthspan.

An Interview with Reason at the Life Extension Advocacy Foundation

Following the launch of Repair Biotechnologies, and since I'll be at the Life Extension Advocacy Foundation's one-day conference, Ending Age-Related Disease, this coming July in New York, I recently answered a few questions and offered a few opinions for the LEAF volunteers. That interview was published yesterday. Regular readers here at Fight Aging! are no doubt all too familiar with many of those opinions already, since I'm not exactly what one might call reticent about putting them forward, but it never hurts to check.

Thanks to the efforts of many advocates, yours included, public perception of rejuvenation is also shifting. How close do you think we are to widespread acceptance?

I don't think acceptance matters - that might be the wrong term to focus on here. Acceptance will occur when the therapies are in the clinic. People will use them, and everyone will conveniently forget all the objections voiced. The most important thing is not acceptance but rather material support for development of therapies. The help of only a tiny fraction of the population is needed to fund the necessary research to a point of self-sustained development, and that is the important thing. Create beneficial change, and people will accept it. Yet you cannot just go and ask a few people. Persuading many people is necessary because that is the path to obtaining the material support of the necessary few: people do not donate their time and funds to unpopular or unknown causes; rather, they tend to follow their social groups.

Presently, rejuvenation is a relatively unknown topic; people who say they're against this technology probably don't think it's a concrete possibility anyway. However, as more important milestones will be reached - for example, robust mouse rejuvenation - this might change. Do you think that these milestones will result in opponents changing their attitudes or becoming more entrenched?

Opposition to human rejuvenation therapies is almost entirely irrational; either (a) it's a dismissal of an unfamiliar topic based on the heuristic that 95% of unfamiliar topics turn out to be not worth the effort when investigated further, or (b) it's a rejection of anything that might result in sizable change in personal opinion, life, and plans, such as the acceptance of aging and death that people have struggled to attain. This sort of opposition isn't based on an engagement with facts, so I think a sizable proportion of these folk will keep on being irrational in the face of just about any scientific advance or other new factual presentation short of their physicians prescribing rejuvenation therapies to treat one or more of their current symptoms of aging.

On the other hand, there will be steady progress in winning people over in the sense of supporting rejuvenation in the same sense as supporting cancer research: they know nothing much about the details, but they know that near everyone supports cancer research, and cancer is generally agreed to be a bad thing, so they go along. Achieving this change is a bootstrapping progress of persuading opinion makers and broadcasters, people who are nodes in the network of society. Here, milestones and facts are much more helpful.

After years of financially supporting other rejuvenation startups, you're now launching your own company focused on gene therapies relevant to rejuvenation. Your company's first objective is thymic regeneration. Why do you think the thymus is the ideal initial target for your work?

It is a very straightforward goal, with a lot of supporting evidence from the past few decades of research. It think it is important to set forth at the outset with something simple, direct, and focused, insofar as any biotechnology project can be said to have those attributes. This is a part of the SENS rejuvenation research agenda in the sense of cell atrophy: the core problem is loss of active thymic tissue, which leads to loss of T cell production and, consequently, immunodeficiency. However, the immune system is so core to the health of the individual that any form of restoration can beneficially affect a great many other systems. The many facets of the immune system don't just kill off invading pathogens; they are also responsible for destroying problem cells (cancers, senescent cells), and they participate in tissue maintenance and function in many ways.

You are using gene therapy; why have you chosen this delivery method specifically and not, for example, a small-molecule approach?

If your aim is to raise or lower expression of a specific protein, and you don't already have a small molecule that does pretty much what you want it to do without horrible side-effects, then you can pay $1-2M for a shot at finding a starting point in the standard drug discovery databases. That frequently doesn't work, the odds of success are essentially unknown for any specific case, and the starting point then needs to be refined at further cost and odds of failure. This is, for example, the major sticking point for anyone wanting to build a small-molecule glucosepane breaker - the price of even starting to roll the dice is high, much larger than the funding any usual startup crew can obtain.

On the other hand, assuming you are working with a cell population that can be transduced by a gene therapy to a large enough degree to produce material effects, then $1-2M will fairly reliably get you all the way from the stage of two people in a room with an idea to the stage of having animal data sufficient enough to start the FDA approval process.


Improved Approaches to Messing with Metabolism Will Use Gene Therapies

I see that noted geneticist George Church has been discussing his new company Rejuvenate Bio in the media. The projects undertaken there are the logical progression of attempts to slow aging with pharmaceuticals, moving them into the era of gene therapy. This is still guided by the a philosophy of what Aubrey de Grey would call "messing with metabolism." This means that researchers are attempting to alter the amounts of specific proteins in ways that adjust the operation of metabolism into what is hopefully a more optimal state, one in which cell and tissue damage, or the consequences of that damage, accrue more slowly. Gene therapies are far more effective tools than pharmaceuticals when it comes to achieving this outcome with minimal side-effects, and there are many candidate genes to explore.

This is not, however, likely to be as effective as repairing the underlying damage that causes aging. It is tinkering with the broken state of metabolism that arises due to damage, trying to make it more functional without addressing the root cause of its problems. Clearly it is possible to do useful things via this approach, as demonstrated by the existence of statins, first generation stem cell therapies, and the like, but all of these technologies are in principle very limited in comparison to what might be achieved by reversing the root causes of aging.

Professor George Church of Harvard Medical School has co-founded a new startup company, Rejuvenate Bio, which has plans to reverse aging in dogs as a way to market anti-aging therapies for our furry friends before bringing them to us. The company has already carried some initial tests on beagles and plans to reverse aging by using gene therapy to add new instructions to their DNA. If it works, the goal is ultimately to try the same approach in people. "Dogs are a market in and of themselves. It's not just a big organism close to humans. It's something that people will pay for, and the FDA process is much faster. We'll do dog trials, and that'll be a product, and that'll pay for scaling up in human trials."

Church and the team also understand that developing therapies that address aging in humans and getting them approved would not be so easy. It would take too long to prove something worked. "You don't want to go to the FDA and say we extend life by 20 years. They'd say, 'Great, come back in 20 years with the data.'" So, the team has taken a different tack; rather than aiming to increase human lifespan as its main focus, it is instead focusing on the typical age-related diseases common to dogs. The hope is that by targeting the aging processes directly, these diseases could be entirely prevented from developing. If successful, this would lend additional supporting evidence that directly treating aging to prevent age-related diseases could also work in humans.

The lab has been working on a collection of over 60 different gene therapies and has been testing their effects both individually and in combinations. The team intends to publish a report on an approach that extends mouse lifespan by modifying two genes that protect against heart and kidney failure, obesity, and diabetes. Professor Church has commented that the results of this study are "pretty eye-popping". The new startup has been contacting dog breeders, veterinarians, and ethicists to discuss its plans for restoring youth and increasing the lifespan of dogs. Its plan is to gain a foothold in the pet market and then use that as the basis for moving therapies to people.


Arguing for Mitochondrial ROS to Cause Stochastic Nuclear DNA Damage that then Causes Cellular Senescence

The open access paper I'll point out today ties together a number of common themes in aging research. The authors propose that mitochondrial production of reactive oxygen species (ROS) is a significant cause of stochastic nuclear DNA damage, which in turn is a significant cause of cellular senescence. Those issues can then also disrupt mitochondrial function to increase ROS production, forming a feedback loop. In this view of the driving processes of aging, mitochondria are largely at fault for anything that can be pinned to rising levels of random mutations in nuclear DNA: cancer risk, cellular senescence, generally increased levels of cellular malfunction, and so forth.

An important caution regarding this paper is that the researchers used mice with a DNA repair deficiency in order to assemble their data. Such animals exhibit the appearance of accelerated aging, but it isn't in fact accelerated aging. It is usually an excess of cellular damage that isn't all that relevant in normal aging - any sort of global dysfunction in cells will tend to share high level similarities with aging, even if the damage is different. When it is significantly different, however, you usually can't learn much from it. So whether or not work in such mice is in fact useful in understanding normal aging depends very strongly on the low-level biochemical details in question. That can be hard to judge for those of us who are not life scientists.

The approach to the problem taken here sounds basically sensible as it is described below, but it nonetheless calls out for some form of confirming study in normal mice in order to rule out any peculiarity of DNA repair deficiency. One possibility would be to take one of the existing mitochondrially targeted antioxidant compounds and design a study that specifically evaluates reduced nuclear DNA mutation and reduced cellular senescence burden as a result of administration. Researchers have already run numerous studies in mice with these compounds, and some of that existing data might be helpful from this point of view. I note, however, that those studies didn't produce very large gains in life span where those gains were measured, which should perhaps temper our enthusiasm for this whole line of thought.

Spontaneous DNA damage to the nuclear genome promotes senescence, redox imbalance, and aging

Cellular senescence was recently established to play a causal role in aging and many age-related diseases. Senescence is a programmed cell fate characterized by growth arrest, a metabolic shift, resistance to apoptosis and often a secretory phenotype. The senescent cell burden increases with age in virtually all vertebrates. In replicating human cells, shortened telomeres drive senescence. It has become increasingly clear that non-replicating cells also undergo senescence. However, in non-dividing cells, which are the majority of cells in mammalian organisms, the cause of senescence is not clear.

A variety of cellular stressors including genotoxic, proteotoxic, inflammatory, and oxidative have been implicated in driving senescence. However, senescence itself is associated with many of these cellular stressors, making it very difficult to decipher cause and effect. For example, DNA damaging agents definitively cause increased senescence (e.g. in cancer patients). Yet senescent cells are defined by persistent activation of the DNA damage response, increased expression of surrogate markers of DNA damage and are able to trigger genotoxic stress in neighboring cells. Therefore, in vivo, the importance of DNA damage as a driver of senescence and aging is debated.

Even less is known about endogenous DNA damage as a potential driver of senescence and aging. The vast majority of evidence implicating DNA damage in senescence comes from experiments implementing very high doses of environmental genotoxins such as ionizing radiation or doxorubicin. Also of note, all genotoxins damage not only DNA, but also all cellular nucleophiles including phospholipids, proteins, and RNA. Thus, it remains unknown whether physiological levels of spontaneous DNA damage is sufficient to drive cellular senescence.

A major source of endogenous DNA damage is reactive oxygen species (ROS) produced during mitochondrial-based aerobic metabolism. Some mitochondrial-derived ROS, such as H2O2, can diffuse throughout the cell, resulting in oxidative damage to lipids, proteins, RNA and DNA. Thus, mitochondrial dysfunction, which leads to an increase in ROS production, was proposed to be central to the aging process. However, this too remains controversial.

To address these gaps in knowledge, we utilized a genetic approach to increase endogenous nuclear DNA damage in mice. ERCC1-XPF is an endonuclease complex required for nucleotide excision repair, interstrand crosslink repair and the repair of a subset of DNA double-strand breaks. Mutations that mediate reduced expression of this enzyme cause accelerated aging in humans and mice. Genetic depletion of DNA repair mechanisms does not increase the amount of damage incurred, it simply accelerates the pace at which damage triggers a demonstrable physiological impact, affording an opportunity to investigate the role of endogenous nuclear DNA damage in driving senescence.

Here, we demonstrate that Ercc1-/Δ mice accumulate oxidative DNA damage and senescent cells more rapidly than age-matched wild-type (WT) controls, yet comparable to WT mice over two years of age. Surprisingly, we found that Ercc1-/Δ mice are also under increased oxidative stress. Increased ROS production and decreased antioxidant buffering capacity contributed to the oxidative stress, which was also observed in aged WT mice. Treatment of Ercc1-/Δ mice with a mitochondrial-targeted radical scavenger (XJB-5-131) was sufficient to suppress oxidative DNA damage, senescence, and age-related pathologies. These data demonstrate that damage of the nuclear genome arising spontaneously in vivo is sufficient to drive cellular senescence. Our data also demonstrate that endogenous DNA damage, as a primary insult, is able to trigger increased reactive oxygen species (ROS) and further oxidative damage in vivo.

By definition, the primary insult in untreated Ercc1-/Δ mice is unrepaired endogenous DNA damage to the nuclear genome. Not surprisingly, the Ercc1-/Δ mice accumulate senescent cells more rapidly than WT mice. This formally demonstrates that physiologically-relevant types and levels of endogenous DNA damage are able to trigger the time-dependent accumulation of senescent cells. Chronic administration of XJB-5-131 significantly reduced both oxidative DNA damage and senescence. The reduced level of senescent cells corresponded to a reduction in age-related morbidity. The observation that suppressing oxidant production is sufficient to decreases senescence indicates that reactive species are required to ultimately cause or maintain senescence in response to genotoxic stress.

Increased Mitochondrial DNA Copy Number Slows Vascular Aging in Mice

The open access paper here presents an interesting result in mitochondrial biology. Mitochondria are the power plants of the cell, a herd of bacteria-like structures responsible for packaging chemical energy store molecules. They have their own small genome of a few mitochondrial genes. A mitochondrion may have one or several copies of this genome, and mitochondria promiscuously fuse together, divide, and swap around their component parts from one to another. This makes it quite hard to understand how their age-related dysfunction and damage progresses in detail.

Nonetheless, it is well demonstrated that mitochondria become progressively less functional with advancing age, and this is particularly relevant in energy-hungry tissues such as muscles and the brain. Some of this decline may be reaction to forms of cell and tissue damage, and some of this is due to stochastic mutational damage occurring to mitochondrial DNA. In this context, the researchers here show that forcing an increase in the number of copies of mitochondrial DNA can maintain mitochondrial function in old age, and thereby slow vascular aging. It remains unclear, however, as to the exact chain of mechanisms that make this the case: the causes and immediate consequences of an age-related reduction in the number of copies of mitochondrial DNA are not well understood at this point in time.

Mitochondria contain multiple copies of mitochondrial DNA (mtDNA) that encode ribosomal and transfer RNAs and many essential proteins required for oxidative phosphorylation. Loss of mtDNA integrity by both altered mitochondrial DNA copy number (mtCN) and increased mutations is implicated in cellular dysfunction with aging. Reactive oxygen species (ROS), many of which are generated by mitochondria, also increase with age. However, the role of mitochondria in aging may extend beyond ROS, and it is unclear whether decreased mitochondrial function promotes vascular aging directly or is just a consequence of aging.

Aging of the large conduit arteries is a major cause of morbidity and mortality, contributing to hypertension (high blood pressure) and stroke. Currently, it is unclear what the earliest time points that constitute vascular aging in laboratory mice are, which physiological measures of large artery stiffness correspond most closely to humans, and whether similar processes underlie changes in mechanical properties in mouse and human arteries. Aging research is time-consuming and expensive because of the long time courses needed. Therefore, identifying the earliest time points that show the most sensitive and reproducible changes and parameters is crucial in obtaining scientific consensus for mouse models of vascular aging.

We examined multiple parameters of vascular function, histological markers, and markers of mitochondrial damage and function during normal vascular aging, and the effects of reducing or augmenting mitochondrial function on the onset and progression of vascular aging. We identify early, standardized time points and reproducible physiological parameters for vascular aging studies in mice. Vascular aging begins at far earlier time points than previously described in mice, with compliance, distensibility, stiffness, and pulse wave velocity (PWV) being the best discriminators for normal aging and manipulations. Mitochondrial DNA copy number and mitochondrial respiratory function are reduced when functional and structural manifestations of vascular aging begin. Rescue of the copy number deficit observed in normal aging improves mitochondrial respiration and delays all parameters of vascular aging, while reduced mtDNA integrity accelerates vascular aging. Together these data highlight the direct role of mtDNA-mediated mitochondrial dysfunction in the progression of vascular aging.


Unexpectedly Better Results Cause Phase III Trial Failure for Gensight

Clinical trials must produce exactly the expected result or they are declared a failure. A clinical trial can fail by producing unexpected benefit, and this has happened to Gensight Biologics' work on allotopic expression of the mitochondrial NH4 gene, aimed at the treatment of inherited retinal degeneration caused by mutation in NH4. Allotopic expression is a process in which a copy of the correctly formed gene is placed into the cell nucleus, suitably altered to enable transport of the protein produced back to the mitochondria where it is need.

In a sane world, this therapy would long ago have been available to anyone willing to accept the risk, based on positive earlier results and lack of serious side-effects. In that same sane world, the therapy would now be available to anyone willing undergo the risk of gaining a greater benefit than was hoped for. Unfortunately we don't live in that world, and Gensight will now have to run further very expensive trials before regulators will permit the treatment to reach the clinic.

We watch progress at Gensight because allotopic expression of NH4 is one-thirteenth of a rejuvenation therapy - Gensight is the result of research supported and encouraged by the Methuselah Foundation some ten years ago. If all thirteen important mitochondrial genes can be copied into the cell nucleus, then that would make an individual largely invulnerable to stochastic mitochondrial DNA damage and resultant dysfunction. It is thought that this is an important root cause of degenerative aging.

GenSight Biologics, a biopharma company focused on discovering and developing innovative gene therapies for retinal neurodegenerative diseases and central nervous system disorders, today announced topline results from the REVERSE Phase III clinical trial evaluating the safety and efficacy of a single intravitreal injection of GS010 (rAAV2/2-ND4) in 37 subjects whose visual loss due to 11778-ND4 Leber Hereditary Optic Neuropathy (LHON) commenced between 6 and 12 months prior to study treatment.

Topline results further highlight the favorable safety and tolerability profile of GS010, and demonstrate a clinically meaningful improvement of +11 ETDRS letters in treated eyes at 48 weeks as compared to baseline in all 37 patients. Unexpectedly, untreated contralateral eyes (treated with a sham injection) show a similar improvement of +11 ETDRS letters. Due to this improvement in untreated eyes, the trial did not meet its primary endpoint, defined as a difference of improvement in visual acuity in GS010-treated eyes compared to sham-treated eyes at 48 weeks.

The improvement of visual acuity in sham-treated eyes was unexpected based on the natural history of LHON, for which partial spontaneous recovery is reported in only 8-22% of patients with the G11778 ND4 mutation. "This meaningful improvement of untreated eyes observed at week 48 was totally unexpected given what is known and has been published about the natural history of this devastating disease. We will continue to analyze the data to better understand our results, but they suggest that GS010 benefits both eyes in a way that is still to be understood. The fact that structural measures of the retina showed such a large statistical difference with treatment is compelling and objective evidence that this gene therapy protects the integrity of many retinal ganglion cells from the damage of LHON."

Based on preliminary analysis of the safety data, GS010 was well tolerated after 48 weeks. The ocular adverse events most frequently reported in the therapy group were mainly related to the injection procedure, except for the occurrence of intraocular inflammation (accompanied by elevation of intraocular pressure in some patients) that is likely related to GS010, and which was responsive to conventional treatment and without sequelae. There were no withdrawals from the trial. GS010 is currently being investigated in two additional ongoing Phase III trials, RESCUE and REFLECT, while patients in REVERSE continue to be followed for another 4 years.


SENS Research Foundation 2017-2018 Annual Report

The latest annual report from the SENS Research Foundation is out, covering progress in 2017 and early 2018. The SENS Research Foundation remains one of the very few philanthropic organizations focused on speeding the development of rejuvenation therapies - something we hope to see change in the years to come, as more support arrives for this field. The foundation staff use the charitable donations provided by our community to fund research programs specifically focused on areas of biotechnology that are presently blocked or neglected, but that can potentially give rise to ways to repair, remove, or work around the cell and tissue damage that causes aging. They also support networking, advocacy, and conference series designed to build bridges between academia and industry in order to smooth the road towards commercial development of advances developed in the laboratory.

Along with the Methuselah Foundation, where the SENS rejuvenation research programs started, the SENS Research Foundation has done a great deal to change the way in which the scientific community and broader public view aging. Back at the turn of the century, when the SENS program was proposed, and Aubrey de Grey presented his synthesis of existing evidence for seven broad categories of molecular damage that caused aging, the leaders in the research and funding communities actively suppressed any effort to work on or discuss the treatment of aging as a medical condition. It was career suicide to openly work towards that goal. The change achieved since then has been profound, and now researchers openly debate how best to go about treating aging to extend healthy life spans. This required a great deal of hard work.

A few strands of rejuvenation research have moved into clinical development in recent years: the removal of senescent cells, and clearance of a few kinds of harmful metabolic waste. As a part of its efforts, the SENS Research Foundation can now point to the ongoing development of startup biotechnology companies that it helped to seed fund, in some cases in partnership with the Methuselah Foundation. We will be seeing more of this in the years ahead: successful young companies can typically raise a great deal more funding than is available via philanthropy, and their efforts also go a long way towards attracting more validation and attention to the field.

SENS Research Foundation 2018 Annual Report

The valley of death - the chasm between innovation and availability that has become such a common theme in drug development - is especially wide for the field of rejuvenation biotechnology. Besides the time and resources required to develop any medicine, the few who initially strove to develop this field faced the added challenge of demonstrating that we could feasibly intervene to prevent age- related disease by redressing the underlying damage that causes such disease. There is scarcely a biotech organization that hasn't used, at some point, a 'bridging the gulf' metaphor to address the valley of death. But it has been such an integral part of our identity that we built it into our brand; the multi-colored ribbon of our logo having been designed to evoke both double-helix and suspension bridge imagery (and yes, it's always had seven twists).

Upon the launch of his project to build the Golden Gate Bridge, Chief Engineer Joseph Strauss had this to say: "It took two decades and two hundred million words to convince people the bridge was feasible." We have at times wondered whether even that would be sufficient. But with the diligent efforts of our own research teams and those of a growing number of institutions, the question of feasibility has increasingly fallen away. Today we see our research programs successfully translating into development, our former students becoming rejuvenation biotechnologists and developers, new collaborative energy from the investment arena, and the groundwork being laid for regulatory models for rejuvenation interventions.

Programmatic Investments

Antoxerene, a portfolio company of Ichor Therapeutics, is a small molecule drug discovery company that focuses on molecular pathways of aging. To our knowledge, Antoxerene is the first and only company with small molecule hits on the p53/FOXO4 pathway, which has been implicated in cellular senescence. Antoxerene is developing these hits for eventual clinical use.

Lysoclear, a portfolio company of Ichor Therapeutics, is an ophthalmology company developing an enzyme therapy for age-related macular degeneration and Stargardt's disease. In 2017, the company completed pivotal proof-of-concept studies with its first generation enzyme lead and conducted extensive mechanistic work to clarify the role of retinal lipofuscin in the onset and progression of macular degeneration. These results have been submitted for peer-reviewed publication. Lysoclear is now optimizing its enzyme into a drug candidate in preparation for IND enabling studies.

Oisín is developing a DNA construct that recognizes that a cell has become senescent and then destroys it, and safely and efficiently delivering this construct into cells throughout the body. Both goals have been achieved in pioneering proof of concept experiments in 2016. Now they are embarked on experiments that will show improvements in both healthspan and lifespan in model organisms from mice to primates.

Arigos has made great strides towards the banking of human organs, demonstrating functional and structural recovery of similarly-sized tissues from below -120°C. Their ability to cryopreserve large, complex tissue structures is a breakthrough in medical research. Stable banking for larger tissue structures and organs could more than double the number of transplants performed each year and would eliminate five of the current organ waiting lists within a few years.


The MitoSENS team is working on a potential rejuvenation biotechnology to sustain and recover electron transport chain (ETC) function: allotopic expression of functional mitochondrial genes. Allotopic expression involves placing "backup copies" of all of the protein-coding genes of the mitochondria in the "safe harbor" of the nucleus, which can then deliver the proteins mitochondria need to build their ETC and continue producing energy normally, even when the original mitochondrial copies have been mutated. The team is working to establish a "landing pad" in mouse cells to enable reliable and safe gene therapy for animal studies, via the Maximally-Modifiable Mouse Project. They expect to soon begin preliminary in vivo testing of allotopic ATP8 in transgenic mice. Meanwhile, they are also looking to expand the strategy to other mitochondrial genes and further improve allotopic expression of the ATP6 gene.

A major cause of crosslink accumulation in aging is Advanced Glycation Endproducts (AGE), and one AGE in particular - called glucosepane - is currently thought to be the single largest contributor to tissue AGE crosslinking, with consequences such as arterial stiffening. The Yale team is developing new reagents and approaches to accelerate glucosepane research. They now are able to synthesize all three conformational variants (diastereomers) of glucosepane that may occur in vivo. They are also working to generate antibodies that can then be used to label glucosepane crosslinks in tissue samples and in vivo. Further, the Yale team has identified some potential glucosepane-breakers, about which we hope to be able to make further announcements this year pending publication in a peer-reviewed journal.

One of the reasons why senescent cells secrete inflammatory signals is to attract Natural Killer (NK) immune cells, which then clear senescent cells from the tissue. Despite this, senescent cells accumulate over the course of the lifespan. A critical question is therefore that of how some senescent cells are able to escape immune surveillance and what might be done to overcome their defenses. Dr. Judith Campisi, a renowned pioneer in senescence research, is answering this question and developing strategies to enhance immune clearance of senescent cells. Campisi's group has already discovered that one of the key NK cell binding markers on the surface of senescent cells begins to disappear within weeks of the cell becoming senescent. Without this marker ligand, NK cell binding cannot occur, and the NK cells' killing ability cannot be unleashed. Early results suggest some potential strategies for restoring NK cell immunosurveillance of senescent cells.

Aggregates composed of aberrant tau protein accumulate with age, both inside and outside of neurons. These aggregates are an important driver of neurodegenerative diseases of aging. One possible basis for this intracellular accumulation may be as a consequence of age-related lysosomal dysfunction that is driven by the accumulation of other kinds of intracellular aggregates. As such, this deleterious accumulation might be reversed if lysosomal function could be restored. This line of investigation will inform strategy: do we need a custom solution just for intracellular tau aggregates, or will clearing other age-related lysosomal junk be sufficient to restore an existing capacity to eliminate these aggregates? The Andersen lab is testing this possibility using neurons that express mutant versus wild-type human tau.

Atherosclerotic lesions form when immune cells called macrophages take in 7-ketocholesterol (7-KC) and other damaged cholesterol byproducts in an effort to protect the arterial wall from their toxicity but ultimately fall prey to that same toxicity themselves. Dr. O'Connor's team has identified a family of small molecules that may be able to selectively remove toxic forms of cholesterol from human blood, which would help combat the development of atherosclerosis. They have been testing its effects and those of closely-related compounds in human blood samples, seeking potential modifications and combinations that would maximize selectivity for toxic cholesterol byproducts while leaving native cholesterol alone.

Investigations of p66(Shc) Knockout Mice Continue

Gene knockout of p66(Shc) is one of the many genetic alterations shown to extend mouse life span. The role of p66(Shc) in the intersection of aging and metabolism has been investigated for more than two decades now, though its ability to extend life is disputed by at least some researchers - the data isn't as reliable as is the case for some other approaches. This is a common issue for methods that alter the operation of metabolism, as metabolism is very complex, and all sorts of other factors beyond the intended genetic adjustment might have a meaningful influence.

To the extent that p66(Shc) knockout improves health and function in mice, it appears to work via an improvement in mitochondrial activity, or a slowing in the age-related mitochondrial dysfunction that affects unmodified mice. Mitochondria in older individuals produce more oxidative molecules, are less efficient at their primary task of producing chemical energy stores, and their appearance changes, all of which is slowed in p66(Shc) knockout mice. Which is interesting, but what do we get out of this at the end of the day? The papers produced as a result of research into p66(Shc) this year look little different in content and character from those of decade ago; there is little apparent likelihood of a therapy to slow the progression of aging emerging from this fundamental science in the near future.

In the last years, more cases of cooperation between reactive oxygen species (ROS) and aging-regulating genes have been established in senescence and aging development. The adaptor protein p66Shc is a genetic determinant of lifespan that regulates ROS metabolism and cellular apoptosis. p66Shc ablation in mice is translated into a significant decrease in mitochondria-produced ROS and a 30% increase in lifespan. These knockout mice for p66Shc (p66Shc(-/-)) have been shown to be thinner, to exhibit an increased metabolic rate, and to have less body fat than their wild-type littermates. And more remarkably, they have been described as an animal model of healthy aging with better cognitive abilities at adulthood in a spatial memory task and improved physical performance at senescence.

Based on the improved bioenergetics parameters observed in p66Shc(-/-) mice and the already accepted downregulated mitochondrial biogenesis in aging, it is interesting to study how p66Shc impacts on mitochondrial quantity and structure. The mitochondrial content of a sample can be determined using different methods that provide information about mitochondrial biogenesis and tissue's oxidative capacity. Mitochondrial DNA (mtDNA) content relative to nuclear DNA was determined by real-time qPCR in brain samples of the study groups and shown as a percentage of the 3-month-old wild type (WT) relative mtDNA content. During aging, mitochondrial content was reduced by 30% in the WT group, while in the p66Shc(-/-) group, a 45% increase was observed.

For both WT and p66Shc(-/-) 3-month-old mice, normal size and volume mitochondria were observed, with predominantly tubular-shaped mitochondria (70% of total measured mitochondria), while the remaining displayed round (fragmented) morphology. However, at the end of their life, the time point of maximal ROS production, 24-month-old WT mouse brain slices were characterized by decreased tubular mitochondria (-44%) and increased round-shaped mitochondria (+120%). This age effect in mitochondrial morphology was partially mitigated in 24-month-old p66Shc(-/-) mice, to the extent that both types of mitochondrial populations coexisted in this group (55% tubular mitochondria) showing an intermediate phenotype between 3- and 24-month-old WT mice.


Burying Dead Cells Requires Oxidative Signaling

The research here considers how the debris of dead cells is cleared away, something that has to happen efficiently in order to avoid inflammation and other issues in tissue. As is true of a range of beneficial processes in the body, this turns out to require a certain level of oxidative signaling. This is probably one of the reasons why long-term general use of antioxidants appears to be, on balance, modestly harmful to health and longevity. The process is interesting when considered in the context of recent work on necroptosis, a fairly recently discovered form of programmed cell death that results in inflammatory cell debris, as well as past considerations of cellular debris as a mechanism by which excess fat tissue produces chronic inflammation. Is this sort of thing important in the progression of aging, more of a root cause of many issues rather than a downstream consequence of failing maintenance processes? That is an interesting question.

Billions of cells die daily as a consequence of regular wear and tear, tissue turnover and during an inflammatory response. The body dedicates a significant amount of energy in the specific recognition and uptake of these dead cells via specific pathways. If you don't bury the dead cells, they can burst open and cause harm, however the underlying mechanisms are incompletely characterized. Now, researchers have uncovered how NADPH-oxidase is activated to generate reactive oxygen species (ROS) in macrophages, a kind of white blood cell that eats dead cells. These cells also are involved in getting rid of viruses and bacteria.

The presence of ROS is critical as its generation drives additional mechanisms involved in the digestion of cellular corpses to perform at an optimal level. This allows the macrophage to complete the digestion process of efferocytosis. "Independent of their role in microbial killing, we are gaining even greater appreciation of ROS for their huge role in the regulation of host immune response. Uncovering this role of ROS in the clearance of dead cells sheds some mechanistic insights on how oxidants function in limiting of host inflammation rather than activating it. When our bodies produce too much or too little ROS, we become pre-disposed to autoimmune disease and chronic inflammation. Producing just enough - the optimal level - is what's needed."


Circular RNAs are Enigmatic, and Grow in Number with Age

Large swathes of cellular biochemistry remain comparatively unexplored and uncategorized. Any process or cellular component discovered in the past twenty to thirty years still has, at the very least, sizable gaps in the body of knowledge relating to it. Cells as a whole are by no means fully understood at the detail level - and this is exactly why, if we want to see significant progress towards human rejuvenation in the next few decades, the approach taken has to be to reverse the known root causes of aging, while tampering as little as possible with the way in which cells work, and let the cells take care of everything else. Other approaches are based on altering the way in which cells operate. These require far too much new work and new knowledge in order to safely implement, or even understand how to produce effective results.

Today's topic is circular RNA (circRNA), a form of RNA quite prevalent in cells, but that was only discovered in the 1990s. These molecules are highly varied in form and function, and what exactly those functions might be remains largely unknown. Interestingly, the open access paper I'll point out today reports that circRNAs increase in number inside cells with advancing age, particularly in long-lived cells. Does that mean they are significant in aging? Perhaps, perhaps not. It is a topic to watch in the years ahead, but the research community is presently some distance removed from being able to answer questions of this sort regarding circRNAs. Work is still focused on the foundation of a basic understanding. The sort of extensive investigation of relationships and mechanisms that takes place for other forms of RNA still lies ahead for circRNAs.

Global accumulation of circRNAs during aging in Caenorhabditis elegans

Circular RNAs (circRNAs) have recently been identified as a natural occurring family of widespread and diverse endogenous RNAs. They are highly stable molecules mostly generated by backsplicing events from protein-coding genes. The expression trends of circRNAs are only recently emerging. Most circRNAs are derived from protein-coding genes, and thus one challenge in mapping and quantifying circRNAs is to distinguish reads that can be uniquely ascribed to circular molecules versus linear RNAs emanating from the same gene. Elements located within introns flanking circularizing exons play a role in promoting circRNA biogenesis, and several RNA binding proteins and splicing factors have been shown to influence circRNA expression.

Despite the current interest in circRNAs, their functions are only beginning to emerge. Recent reports have identified roles for circRNAs in regulating transcription, protein binding, and sequestration of microRNAs. Some circRNAs can be translated via cap-independent mechanisms to generate proteins. Moreover, circRNAs have been implicated in antiviral immunity, and expression patterns of circRNAs in the brain suggest that they might serve important functions in the nervous system.

Several RNA-seq studies have found that circRNAs are differentially expressed during aging. Over 250 circRNAs increased in expression within Drosophila head tissue between 1 and 20 days of age. Trends for increased circRNA expression have also been identified during embryonic/postnatal mouse development, suggesting that circRNA accumulation might begin early in development. We recently reported that circRNAs were biased for age-accumulation in the mouse brain. In hippocampus and cortex, ~5% of expressed circRNAs were found to increase from 1 month to 22 months of age, whereas ~1% decreased. This accumulation trend was independent of linear RNA changes from cognate genes and thus was not attributed to transcriptional regulation. CircRNA accumulation during aging might be a result of the enhanced stability of circRNAs compared to linear RNAs. Age-related deregulation of alternative splicing leading to increased circRNA biogenesis might also play a role.

C. elegans is a powerful model organism for studying aging. Previously, thousands of circRNAs were annotated from RNA-seq data obtained from C. elegans sperm, oocytes, embryos, and unsynchronized young adults. Here, we annotated circRNAs from very deep total RNA-seq data obtained from C. elegans at different aging time points and uncovered 575 novel circRNAs. A massive trend for increased circRNA levels with age was identified. This age-accumulation was independent of linear RNA changes from shared host genes. Our findings suggest that circRNA resistance to degradation in post-mitotic cells is largely responsible for the age-upregulation trends identified both here in C. elegans, and possibly in neural tissues of other animals.

Aging of the Locus Coeruleus and Loss of Focus in Older Individuals

Cognitive ability has many different dimensions. While all decline with age, it is quite possible for any given individual to find them declining at different rates and at different times, according to the individual distribution of damage and atrophy in the brain. The research noted here illustrates one of many links between a particular cognitive function and a particular location in the brain. In most cases we can look at this sort of evidence and consider that it would be very helpful to have a way to (a) spur greater generation of new cells in the brain, that can integrate into tissues, repair areas of damage, and restore lost function, and (b) clear out the protein aggregates and other forms of metabolic waste associated with the progression towards neurodegenerative disease.

Older adults appear more easily distracted by irrelevant information than younger people when they experience stress or powerful emotions - and a specific network in the brain recently identified as the epicenter for Alzheimer's and dementia may be to blame. A study finds that seniors' attention shortfall is associated with the locus coeruleus, a tiny region of the brainstem that connects to many other parts of the brain. The locus coeruleus helps focus brain activity during periods of stress or excitement.

Increased distractibility is a sign of cognitive aging. The study found that older adults are even more susceptible to distraction under stress or emotional arousal, indicating that the locus coeruleus' ability to intensify focus weakens over time. For instance, if an older adult is taking a memory test in a clinician's office, he or she may be trying hard to focus but will be more easily distracted than a younger adult by other thoughts or noises in the background.

The locus coeruleus appears to be one of the earliest sites of tau pathology, the tangles that are a hallmark of Alzheimer's disease. "Initial signs of this pathology are evident in the locus coeruleus in most people by age 30. Thus, it is critical to better understand how locus coeruleus function changes as we age." The locus coeruleus connects to many parts of the brain and controls the release of the hormone norepinephrine, which influences attention, memory and alertness. Normally, norepinephrine increases the "gain" on neural activity - highly active neurons become more excited, while less active neurons get suppressed.

The researchers recorded physiological arousal and locus coeruleus activity in 28 younger adults and 24 older adults using both brain scans and the measurement of pupil dilation in participants' eyes - an outwardly visible marker for emotional arousal and locus coeruleus activity. During the scans, study participants were shown pairs of photographs. Some trials started with a tone that warned participants that they might receive an electric shock at the end of the trial. Other trials started with a tone indicating that there would be no shock. Participants showed greater pupil dilation and sweat during trials when they might get a shock, indicating greater physiological arousal.

The brain's parahippocampal "place area" becomes active when a person is looking at images of places. In younger adults, expecting a shock amplified activity in the place area when they looked a clear, highlighted image of a building. Pathways in their brains linking the locus coeruleus, the place area, and the frontoparietal network - regions of the brain's cortex that help control what to pay attention to and what to ignore - were uninterrupted. This enabled them to more effectively ignore the information that wasn't important. Older adults, however, showed less activity in the frontoparietal network when anticipating a shock. Their network seemed to no longer effectively respond to signals from the locus coeruleus.


Elite Chess Players and Elite Athletes Have Similar Advantages in Life Expectancy

We can file the study noted here alongside a 2015 twin study as a compelling piece of evidence that stands in opposition to a significant role for high levels of exercise in human longevity. These two are still vastly outnumbered by studies supporting the idea that exercise drives a modestly slower pace of aging, particularly when it comes to the difference between no exercise and some exercise, but they are nonetheless quite clear in and of themselves and quite hard to ignore. The association between athletic performance and greater life expectancy is well proven, but if similar benefits are observed in more cerebral sports, what does that tell us about the underlying mechanisms?

This isn't just a question about physical activity or its absence, or about the confounding correlations between social status, education, intelligence, wealth, and health. There is a growing line of evidence to suggest that associations between intelligence and longevity may be as much mediated by genetics as by greater odds of economic success and sustained better health practices. Natural variation in human longevity is an intensely complex subject, which is one of the many reasons that I'm more in favor of forging ahead with rejuvenation therapies rather than spending significant time trying to understand the present state of aging.

In recent decades much research has been conducted into the longevity of a wide variety of sporting achievers. Almost all of the studies have been focused on a wide range of physical sports. A recent meta-analysis and several recent reviews have consistently found that elite athletes engaged in physical sports have a significant lower rate of mortality compared with the general population. The most comprehensive review, which involved nearly half a million individuals from 57 studies, indicates that the survival advantage for elite athletes was generally between 4 to 8 years longer.

Much less is known about those engaged in mind sports such as chess where the mental exercise component dominates. A search for articles reporting longevity of players of mind sports identified only one early study involving 32 chess players born before 20th century. This study found that professional chess players had shorter lifespans than those players who had careers outside of chess and argued that this might be due to the mental strain of international chess competition.

In the present study, we focused on survival of International Chess Grandmasters (GMs) which represent players, of whom most are professional, at the highest level. In 2010, the overall life expectancy of GMs at the age of 30 years was 53.6 years, which is significantly greater than the overall weighted mean life expectancy of 45.9 years for the general population. In all three regions examined, mean life expectancy of the GMs was longer than that of the matched general population, with gaps between them ranging from 1 to 14 years depending on age. Across the combined sample from 28 countries, the survival advantage over the general population significantly increased over time.

While intelligence may be a potential confounding factor given its positive effect on longevity, evidence of the link between IQ and chess ability is inconclusive. Several studies have failed to find a superiority of expert chess players in a variety of intellectual dimensions. A more likely channel is that to attain the Grandmaster title an individual may be encouraged to make necessary health improvements to improve one's cognitive performance. Although there has been some concern that chess training promotes a sedentary lifestyle that may reduce participation of the chess players in physical activities, this is not supported by existing evidence.

Another causal argument on the effect of developing chess expertise on survival relates to socioeconomic mechanisms. Becoming a chess grandmaster may provide an economic and social boost, which has been strongly linked to increased life expectancy. The relative income and social status benefits of GMs are plausibly highest for individuals in Eastern Europe, which would explain the particularly substantial relative survival advantage we found in this region.


Ladies and Gentlemen, We Are All Dying

Ladies and gentlemen, we are all dying. Our bodies and brains will fail gradually over the next few decades, rendering us first incapacitated, and later dead. Our children will not be spared; they too will suffer this fate a few decades after we do. We face nothing less than a rolling, continual apocalypse. Everyone we know will die. Everything we maintain will crumble in our absence. All we understand and feel, save for the tiny portion of the human experience that we can record, will vanish. We will end.

Do you like life? It is being stolen from you. Inexorable physical processes are degrading the bodily systems needed to walk, think, and enjoy a sunny day for what it is. Muscles weaken. The mind slows. The skin becomes fragile. A billion tiny failures in our cells and their chemistry cascade forward over the years. We rust like iron, distortions and accretions and structural failures taking place in an accelerating and ultimately fatal corrosion.

Ah, but we are complacent in its slowness! To be young is to take function for granted. The old are not real - to be old is not real. Yet the day will come when you can look back and remember a stronger arm and faster mind. The grasping delays when a word or a concept will not come to you, because the internal mechanisms of your brain are faltering? That will happen sooner than you would like. You do not have as much time as you might think. How many summers are there in a life? How many victories? Countless when they lie ahead. All too few when they are half done.

Friends, the progression of medical science from idea to therapy in the clinic is the work of a career. Fifteen to twenty years can pass from start to finish. The young adults who today look upon the opening years of rejuvenation research with interest will no longer be young when the first generation biological repair toolkit of the Strategies for Engineered Negligible Senescence is complete. They will be discovering the first small and concerning failures of their own personal supporting infrastructure. The researchers who led the effort will be retired or retiring, insofar as researchers ever choose to do that. The watch will have changed, the apocalypse taken place, another part of the world lost, destroyed, and mourned again.

And the new young people will be immortal, in their own slow time.

To live is to change. The rolling apocalypse will not go away, but it will be made kind, almost gentle. All that we build will crumble in time, as interest is lost, individuals will evolve to the point of disavowing their earlier selves, knowledge will come and go, and the time after will always be a foreign country to the time before. But there will be no death, no suffering on the vast scale that causes our present world to end over and again. To effect this transformation is the point of our efforts, to sustain human health for as long as we choose through periodic repair of the biological damage that causes aging.

How could we do otherwise? To let aging continue would be barbarism, a rejection of the core precepts of medicine and progress. If we are not building a better world, then why act at all? The capacity to build a better world is the only thing distinguishing us from a rabbit or a rockfall. Everything other than this we do because we must, driven by the biology we inherited, rolling downhill for no reason other than gravity. Are we to be human in truth rather than only in name? Then then we must break all of our physical constraints, not just the few achieved so far. We must prevent all of the suffering, not the little so far addressed. We must bring an end to the poor hand that nature has dealt us, and indeed stop playing the game entirely. In this new era of biotechnology, it is time to grow up, to become adult, to take ownership.

Mesenchymal Stem Cell Therapy Aids Spinal Cord Regeneration in Rats

Arguably the most reliable of first generation stem cell therapies is the transplantation of mesenchymal stem cells. The cells don't last long in the recipient, which is a problem characteristic of all such cell therapies, but the signals they secrete while still alive act to change native cell behavior and suppress inflammation for an extended period of time. Since chronic inflammation degrades tissue maintenance and regeneration, this respite can allow some degree of healing that wouldn't have otherwise occurred - though that benefit is much less reliable than the initial suppression of inflammation.

In the study reported here, researchers turn this set of mechanisms towards regeneration from spinal injury, demonstrating improvements in rats. This is still a long way from comprehensive repair, and much of the discussion centers around just how variable and poorly controlled the cell behavior is in this "most reliable" of cell therapies, but it is a good deal better than failing to intervene in the inflammation that causes scarring following nerve injury. Nerves are in principle capable of regeneration in absence of that scar formation: the mechanisms to support that regeneration exist in mammals, but are not deployed at the right time and in the right way. One line item is the behavior of macrophages, an important player in the intricate dance of cell types involved in regeneration, and whether they adopt the beneficial M2 polarization or the inflammatory M1 polarization. This topic shows up in a lot of regenerative research these days.

There are numerous studies of the therapeutic potential of combinatorial approaches based on mesenchymal stem cell (MSC) therapy and biomaterials for spinal cord injury (SCI) treatment. The transplantation of bone marrow-MSCs combined with a gelatin matrix into the area of complete rat spinal cord transection in the subacute period improves inflammation, stimulates angiogenesis, reduces abnormal cavitation and promotes regeneration of nerve fibers. Human umbilical cord blood-derived MSCs combined with hydrogel implanted into the area of injury can significantly modify the immune response in a proinflammatory environment within the area of SCI by increasing the macrophage M2 population and promoting an appropriate microenvironment for regeneration.

We have studied the effects of the application of adipose-derived mesenchymal stem cells (AD-MSCs) combined with a fibrin matrix on structural and functional recovery following SCI in a subacute period in rats. Our results demonstrated that the AD-MSC application is found to exert a positive impact on the functional and structural recovery after SCI that has been confirmed by the behavioral/electrophysiological and morphometric studies demonstrating reduced area of abnormal cavities and enhanced tissue retention in the site of injury.

We have also assessed astroglial and microglial cells in this study. The results obtained confirm the evidence that AD-MSCs are able to prevent the second phase of neuronal injury by contributing to astroglia and microglia suppression. The latter is consistent with past results, which showed that intravenous injection of AD-MSCs after acute SCI in dogs may prevent further damage through enhancement of antioxidative and anti-inflammatory mechanisms including through lesser microglial infiltration in injured tissue.

Considering their unique therapeutic properties, their ease of accessibility and expansion, AD-MSCs combined with a scaffold reveals a potential for a widespread use in clinical medicine. Nevertheless, there remain critical challenges - (1) standardization of generation protocols, including cell culture conditions, (2) the heterogeneity of secretory phenotype of the MSC population, (3) cellular mechanisms and biological properties of MSCs should be disclosed more clearly, (4) translation to the clinic will need preclinical studies on larger animals, (5) randomized, controlled, multicenter clinical trials are necessary to determine the optimal conditions and doses for MSC therapy.


HMGB1 Accelerates Tissue Regeneration by Increasing Stem Cell Activity

Researchers here outline a method of pushing stem cells in several different tissues into greater activity, thereby accelerating regeneration from injury and potentially improving ongoing tissue maintenance. Given a few more decades of development, regenerative medicine will probably bear little resemblance to today's approaches of cell transplantation, and will instead rely upon a combination of (a) delivering signal molecules or otherwise controlling cell behavior, and (b) repairing damage that accumulates in important cell populations, such as stem cells. If stem cells are kept in a well maintained state, and can be directed to perform as needed, then a major component of the progression of aging will be eliminated. This is, of course, a very large project. There are hundreds of types of cell in the body, and every tissue has its own distinct stem cell populations, all significantly different from one another. The present state of the art in stem cell research is barely the first step on a long road ahead.

Adult stem cells are an essential component of tissue homeostasis with indispensable roles in both physiological tissue renewal and tissue repair following injury. The regenerative potential of stem cells has been very successful for hematological disorders. In contrast, there has been comparatively little clinical impact on enhancing the regeneration of solid organs despite continuing major scientific and public interest. Strategies that rely on ex vivo expansion of autologous stem cells on an individual patient basis are prohibitively expensive, and success in animal models has often failed to translate in late-phase clinical trials. The use of allogeneic cells would overcome the problems of limited supply but commonly entails risky lifelong immunosuppressive therapy. Some safety concerns remain about induced pluripotent stem cells. Furthermore, successful engraftment of exogenous stem cells to sites of tissue injury requires a supportive inductive niche, and the typical proinflammatory scarred bed in damaged recipient tissues is suboptimal.

An attractive alternative strategy, which overcomes many of the limitations described above, is to promote repair by harnessing the regenerative potential of endogenous stem cells. This requires identification of key soluble mediators that enhance the activity of stem cells and can be administered systemically. An interesting observation was made in 1970 that a priming injury at a distant site at the time of or before the second trauma resulted in accelerated healing. This phenomenon was explained only recently, when it was shown that a soluble mediator is released following the priming tissue injury which transitions stem cells elsewhere in the body to a state the authors termed GAlert, which is intermediate between G0 (quiescence) and G1. In the presence of activating factors the primed GAlert cells enter the cell cycle more rapidly than quiescent stem cells, leading to accelerated tissue repair. However, the identity of the soluble mediators that transition stem cells to GAlert remain to be clarified.

Our long-standing interest in tissue injury has recently centered on alarmins, a group of evolutionarily unrelated endogenous molecules with diverse homeostatic intracellular roles, which, when released from dying, injured, or activated cells, trigger an immune/inflammatory response. Much effort has been focused on their deleterious role in autoimmune and inflammatory conditions, and of the few studies that have investigated their role in tissue repair, none has used a combination of human tissues and multiple animal-injury models to characterize their effects on endogenous adult stem cells in vivo. Here we show that high mobility group box 1 (HMGB1) is a key upstream mediator of tissue regeneration which acts by transitioning CXCR4+ skeletal, hematopoietic, and muscle stem cells from G0 to GAlert and that, in the presence of appropriate activating factors, exogenous administration before or at the time of injury leads to accelerated tissue repair.


The First Set of Videos from the Undoing Aging 2018 Conference are Available Online

The first set of presentation videos from Undoing Aging are now available online, via the conference YouTube channel. The conference was held earlier this year in Berlin, jointly hosted by the SENS Research Foundation and Forever Healthy Foundation. The former should need no introduction here, while the latter was founded by philanthropist and investor Michael Greve, a strong supporter of the SENS rejuvenation research programs. By all accounts the conference was a rousing success, adding to a series of past events that have brought together research and industry interests focused on the development of rejuvenation therapies after the SENS model of damage repair. Undoing Aging will return again next year:

Due to the incredible success of the 2018 Undoing Aging Conference in Berlin, Germany, SENS Research Foundation and Michael Greve's Forever Healthy Foundation are pleased to announce that Undoing Aging will return in 2019. This will be an annual conference series, co-sponsored by SRF and FHF to promote awareness of age-related disease and the ongoing scientific breakthroughs in rejuvenation biotechnology. Undoing Aging 2019 will once again focus on bringing together scientists from around the globe in their respective fields who are leading the charge in combating age-related disease. It is through the collaborative efforts of these scientists, investors, policy makers, and media that we will continue to expand the rejuvenation biotechnology industry and reimagine aging.

Kelsey Moody at Undoing Aging 2018

​Kelsey Moody is CEO and Founder at Ichor Therapeutics, a pre-clinical biotechnology company with a focus on drug development for age-associated disease. The two SENS categories that have, arguably, seen the greatest contribution from research funded by the SENS Research Foundation are those relating to damage within cells: mitochondrial mutations and "garbage". Our in-house team has made immense progress recently in rendering mitochondrial mutations harmless by installing "backup copies" in the nuclear genome, while Ichor Therapeutics has taken on one strand of the garbage removal work. Kelsey Moody will describe the state of play in relation to elimination of one of the best-characterised types of intracellular garbage, part of the lipofuscin that drives development of macular degeneration.​

Brian Kennedy at Undoing Aging 2018

Brian Kennedy is internationally recognized for his research in the basic biology of aging and as a visionary committed to translating research discoveries into new ways of delaying, detecting, preventing and treating human aging and associated diseases. From 2010 to 2016 he was the President and CEO of the Buck Institute for Research on Aging, and is now Director of the Center for Healthy Ageing at the Yong Loo Lin School of Medicine at National University Singapore. He here talks about the arrival of Singapore in the aging research community, outlining some of the lines of research underway in that country.

CAR-T Therapy Eliminates Metastatic Colorectal Cancer in Mice

Chimeric antigen receptor T-cell (CAR-T) therapies are a very promising form of cancer immunotherapy. Initially developed for use against blood cancers, they are now showing their worth in the treatment of solid tumors. The most important aspect of this technology platform is not that it is effective, but rather that it can be adapted at an incremental cost to many types of cancer. The future of cancer treatment is entirely determined by choice of strategy: without a broadly applicable therapy with a low cost of adaptation, or ideally a universal therapy that can be applied as-is to any cancer, then there are too few researchers and far, far too many different types of cancer for the progress we'd like to see. If we wish to see cancer controlled in our lifetimes, then the development of general therapies that can be applied to most or all types of cancer is a requirement.

Immunotherapy has given patients and oncologists new options, which for some patients, has meant cures for diseases that had been untreatable. Colorectal cancer has a high mortality rate in advanced stages of the disease with few effective therapies. Researchers have shown that a type of immunotherapy called CAR-T cell therapy, successfully kills tumors and prevents metastases in mouse models of the disease. The work is the last step of preclinical testing prior to human clinical trials. "The antigen we target for colorectal cancer is one that is shared across several high mortality cancers including esophageal cancer and pancreatic cancer. Taken together, 25 percent of people who die from cancer could potentially be treated with this therapy."

CAR-T immunotherapy involves removing a patient's immune cells, engineering them to target the tumor (and only the tumor) and then multiplying those cells en masse before infusing them back into the patient. This powerful burst of targeted immune cells, quickly overcomes the cancer's own immune-suppression to kill the tumors, but requires a marker or homing beacon specific to the cancer. For colorectal cancer that beacon, or tumor antigen, is called GUCY2C. Researchers created a CAR-T therapy made specifically to treat GUCY2C-expressing cancers such as colorectal cancer.

In this study, the researchers tested a human-ready version of the therapy in mice. They showed that mice with human colorectal tumors treated with CAR-T therapy successfully fought the tumor cells. All of the mice studied survived without side effects for the duration of the observation period - or 75 days, compared to a 30-day average survival of mice with control treatment. In order to more closely replicate late-stage disease in humans, researchers also looked at a mouse model of colorectal cancer that developed lung metastases, a common site for metastasis in colorectal cancer patients. Mice that were treated with the CAR-T therapy survived over 100 days with no metastases, whereas the control group survived an average of 20 days. The next steps for the researchers would be a phase 1 clinical trial in humans.


The Gut Microbiome as a Contributing Cause of Sarcopenia

Sarcopenia is the name given to more severe manifestations of the characteristic age-related loss of muscle mass and strength that occurs in all older people. A review of the literature will find ongoing debates over many possible contributing causes of this muscle degeneration, some with better evidence than others, many related to one another: lower dietary intake of protein in the elderly; a failure to correctly process dietary amino acids, particularly leucine; degeneration in the connections between muscle and nervous system; declining activity in muscle stem cell populations; chronic inflammation such as that produced by senescent cells; lack of exercise, particularly strength training; and so forth. From where I stand, I'd say the stem cell explanation is by far the most robust, but then one has to think about why the stem cell populations are in decline.

The open access paper here weighs in with thoughts on age-related changes in the types and behavior of bacteria in the gut as a contributing cause of sarcopenia. A great deal of attention has been given to the gut microbiome in the context of aging in recent years. It is most likely in the same order of magnitude of influence as diet when it comes to the relationship between metabolism and natural variations in the pace of aging, as it mediates diet. These bacteria also produce a wide range of compounds that affect cellular populations throughout the body in various ways, and appear particularly relevant in the chronic inflammation that arises in older individuals. But is it as important as other mechanisms in driving accumulation of the forms of cell and tissue damage outlined in the SENS rejuvenation research proposals, which in turn produce outcomes such as stem cell decline? Perhaps, perhaps not.

The progressive loss of skeletal muscle mass and strength/function, referred to as sarcopenia, is increasingly recognized as a relevant determinant of negative health outcomes in late life. However, the incomplete knowledge of the pathophysiology of sarcopenia hampers the identification of targets that could be exploited for drug development. A growing body of evidence suggests that the innumerable microorganisms that populate the mammalian gastrointestinal tract (gut microbiota) are tightly linked to the aging process of their host. Indeed, this microbial community, mostly composed of bacteria, participates in crucial activities of the gut barrier including the generation of metabolites essential for several host functions and the mediation of exogenous chemical effects on their host.

Age-related changes in the bacterial composition of the microbiota are well known, and alterations of gut microbiota driven by the diet may affect the health of elderly people. However, the complexity of mammalian gut microbiota and the technical challenges in isolating specific "prolongevity" microbial variants limit the knowledge of the microbiota to taxonomic and metagenomic profiling. The functions of individual microbial genes and the molecular mechanisms through which they intervene in host aging are yet to be elucidated. Even less is known about the implications of microbiota-immune system crosstalk on muscle aging.

Most gut microbial changes observed during aging are attributable to diet composition. Both environmental and behavioral factors, including loss of sensation, tooth loss, chewing difficulties, changes in lifestyle, increased consumption of high sugar-fat foods and reduction in plant-based foods have been suggested to influence age-associated diet variations. Taken as a whole, current data supports a link between aging and microbiota alterations relying on a proinflammatory loop. In this context, the age-related decline in masticatory function together with a reduction of appetite and gastrointestinal motility induces dietary changes (reduction in fruits and vegetables) that is reflected in microbiota rearrangement (dysbiosis). This alteration, in turn, can activate a proinflammatory loop fueled by the immunosenescence of gut-associated lymphoid tissue releasing proinflammatory mediators which further favors microbiota rearrangements.

Gut microbiota plays a crucial role in maintaining the balance of pro- and anti-inflammatory responses. Aged gut microbiota may elicit an inflammatory response and display lower capability of counteracting adverse microbes or removing their metabolites. The entrance of pathogens into the intestinal mucosa is also facilitated by the secretion of mucins by intestinal epithelial cells, which is triggered by a reduction in short-chain fatty acids (SCFA) levels in the intestines. SCFA serves within the gut not only as an energy source for colonic epithelial cells but also as strong anti-inflammatory molecules regulating host metabolism and immunity. Increased intestinal permeability to lipopolysaccharide (LPS) is another element in support of a mechanistic link between microbial dysbiosis and systemic inflammation.

In such a context, chronic inflammation may represent the unifying trait of microbial alterations and the development of muscle-wasting conditions in advanced age through a gut microbiota-muscle crosstalk. The molecular players involved in this process are not yet fully understood, but results from several studies indicate the relevant contribution of microbial changes and activity in the gut to the repertoire of inflammatory molecules involved in the milieu characterizing muscle aging. This represents an important matter to be addressed by future investigations to unravel the signaling pathways that may serve as targets for interventions.


Reason Launches Repair Biotechnologies, a Venture to Bring Rejuvenation Therapies to the Clinic: Chief Scientist Sought

Starting a company is a sizable commitment, made in order to produce a better future. With this in mind I have founded Repair Biotechnologies, a new venture that will focus on the development of gene therapies relevant to human rejuvenation. My partner in this, Bill Cherman, is an investor in our rejuvenation research community. He has supported a number of interesting startup biotechnology companies in the past few years, including several that I've also helped in one way or another. Together we intend to carry forward some of the most promising advances produced by the scientific community, picking the best of the many lines of research relevant to human rejuvenation undertaken in recent years. Given even a cursory glance through the Fight Aging! archives, you'll see that we are spoiled for choice: it is a great time to be working in this field.

We are in search of a Chief Scientist! If you have a scientific background in gene therapy, experience in the field, and a taste for the biotechnology startup life, then give some thought to joining our team. The role is a hands-on Chief Scientist: someone with an interest in building new gene therapies for the treatment of aging as a medical condition, and capable of running an ambitious biotechnology program from its earliest stages onward. A history of working through the US or European regulatory system of clinical trials would also be helpful, but is not required. If you are an entrepreneurially minded scientist who knows the ins and outs of modern gene therapy, then we would very much like to hear from you.

The many variants of gene therapy, alongside other novel, long-lasting methods of delivering proteins into cells, collectively form a technology platform that will power much of the future of medicine. This is particularly true for rejuvenation therapies. Just look at the SENS research portfolio: gene therapies are fundamental to, for example, the LysoSENS efforts to deliver enzymes capable of breaking down metabolic waste, or the MitoSENS project to copy mitochondrial genes into the cell nucleus. These are far from the only broad areas of development that are or can be built atop gene therapy, of course.

Out of the gate, our initial focus is on the development of gene therapies to spur regeneration of the thymus. This has the potential to restore production of T cells in older individuals, or other cases in which patients suffer from immunodeficiency and its consequences. The thymus is where T cells mature after their creation in the bone marrow, and its capacity places a limit on the rate at which new T cells take up their duties in the body. The thymus atrophies quite profoundly at the end of childhood, in a process called involution, cutting the rate of T cell creation dramatically. It then declines further over the course of adult life. This loss of function, and falling rate of T cell creation, is an important contribution to the age-related loss of immune function that makes old people frail and vulnerable in comparison to their younger counterparts. This isn't just a matter of defending against pathogens or responding to the yearly influenza vaccination: the immune system is also responsible for suppressing cancerous and senescent cells. All of these functions falter alongside the loss of active thymic tissue.

This can be reversed! It has been reversed in mice, and must now be brought to human medicine. We are embarking upon our first program of work in partnership with the team at Ichor Therapeutics, one of the success stories in the transition of our broader community of scientists and advocates from research to commercial development. Later, other lines of development are planned. Looking at the broader field, as defined in the SENS rejuvenation research proposals, there is a certainly a great deal to accomplish on the road ahead - from where we stand today, all the way to the advent of a comprehensive suite of first generation rejuvenation therapies. We aim to do our part and more in pushing the present state of the art towards that goal. Even in our starting point, consider that there is considerable promise in any meaningful degree of restoration of the aged immune system.

For now, the grand vision of what can be achieved through widespread availability of thymic regeneration therapies lies ahead, past many initial steps: pre-clinical development, clinical trials, validation. We are very excited to embark on this journey, towards the goal of bringing benefits to patients, the goal of turning back aspects of aging and age-related disease. Bill and I look forward to future success in this endeavor.


Nothing in this post should be construed as an offer to sell, or a solicitation of an offer to buy, any security or investment product. Certain information contained herein may contains statements, estimates and projections that are "forward-looking statements." All statements other than statements of historical fact in this post are forward-looking statements and include statements and assumptions relating to: plans and objectives of Repair Biotechnologies' management for future operations or economic performance; conclusions and projections about current and future economic and political trends and conditions; and projected financial results and results of operations. These statements can generally be identified by the use of forward-looking terminology including "may," "believe," "will," "expect," "anticipate," "estimate," "continue", "rankings" or other similar words. Repair Biotechnologies does not make any representations or warranties (express or implied) about the accuracy of such forward-looking statements. Accordingly, you should not place reliance on any forward-looking statements.

Blocking an Astrocyte Receptor Produces Benefits in an Alzheimer's Mouse Model

Researchers here produce an interesting demonstration in a mouse model of Alzheimer's disease. With a comparatively simple change, they rein in the abnormal behavior of astrocyte cells in the brain, and thereby reverse the symptoms of the condition. As noted in the publicity materials, the relevance of mouse models of Alzheimer's to the real thing in humans is often strained - the models are highly artificial, as mice and most other mammals don't normally suffer anything resembling Alzheimer's disease. Thus in cases like this it is hard to say without further work whether or not the discovery is relevant to human biochemistry.

Nonetheless, the supporting cells of the brain, the various categories of neuroglia such as the astrocytes noted here, cannot be ignored in the progression neurodegenerative conditions. They perform a wide range of important functions: clearing up debris and waste; supplying necessary proteins and other molecules to neurons; participating in the maintenance and operation of synaptic connections between neurons; and much more. In neurodegenerative conditions such as Alzheimer's disease, the neuroglia malfunction or change their behavior in harmful ways. Chronic inflammation is one consequence, but also disruption of the normal function of neural networks.

In studies in mice, researchers were able to show that blocking a particular receptor located on astrocytes normalized brain function and improved memory performance. Astrocytes are star-shaped, non-neuronal cells involved in the regulation of brain activity and blood flow. "The brain contains different types of cells including neurons and astrocytes. Astrocytes support brain function and shape the communication between neurons, called synaptic transmission, by releasing a variety of messenger proteins. They also provide metabolic and structural support and contribute to the regulation of blood flow in the brain."

Similar to neurons, astrocytes are organized into functional networks that may involve thousands of cells. "For normal brain function, it is crucial that networks of brain cells coordinate their firing rates. Interestingly, one of the main jobs of astrocytes is very similar to this: to keep neurons healthy and to help maintain neuronal network function. However, in Alzheimer's disease, there is aberrant activity of these networks. Many cells are hyperactive, including neurons and astrocytes. Hence, understanding the role of astrocytes, and targeting such network dysfunctions, holds a strong potential for treating Alzheimer's."

Researchers tested this approach in an experimental study involving mice. Due to a genetic disposition, these rodents exhibited certain symptoms of Alzheimer's similar to those that manifest in humans with the disease. In the brain, this included pathological deposits of proteins known as amyloid-beta plaques and aberrant network activity. In addition, the mice showed impaired learning ability and memory. The scientists targeted a cell membrane receptor called P2Y1R, which is predominately expressed by astrocytes. Previous experiments had revealed that activation of this receptor triggers cellular hyperactivity in mouse models of Alzheimer's. Therefore, the researchers treated groups of mice with different P2Y1R antagonists. These chemical compounds can bind to the receptor, thus switching it off. The treatment lasted for several weeks.

"We found that long-term treatment with these drugs normalized the brain's network activity. Furthermore, the mice's learning ability and memory greatly improved. On the other hand, in a control group of wild type mice this treatment had no significant effect on astrocyte activity. This indicates that P2Y1R inhibition acts quite specifically. It does not dampen network activity when pathological hyperactivity is absent. This is an experimental study that is currently not directly applicable to human patients. However, our results suggest that astrocytes, as important safeguards of neuronal health and normal network function, may hold the potential for novel treatment options in Alzheimer's disease."


The Extracellular Matrix may Determine Regenerative Capacity in Mammals

Very shortly after birth, mammals are capable of far greater feats of regeneration than is the case for older individuals. The research community has put a fair amount of effort into determining why this is the case, though far less progress has been made here than in investigations of the biochemistry of highly regenerative species such as salamanders and zebrafish. This popular science article captures some of the present state of knowledge and uncertainty. Near future advances in medicine arising from this line of research seem unlikely at the present time, as by the look of it there is further to go yet in building a foundation of understanding sufficient to start talking about therapies.

Newborn mice are able to repair damaged heart tissue better than animals injured just a few days later in their lives. What accounts for this regenerative capacity, and exactly when and why it disappears, have been unanswered questions. A new report posits that the extracellular matrix (ECM) gets in the way of heart tissue renewal. The investigators also found that scarring was minimal in mice injured on their first day of life, but damage occurring after that, even just a day later, led to large fibrotic scars. Other scientists are skeptical that what the researchers observed is true regeneration, arguing that the team did not actually show the growth of new muscle. "There is a problem in this research field that we rely on this fibrosis hallmark because the extent of ventricle outgrowth is very hard to determine. If fibrosis is absent, people are very eager to conclude, 'OK, this is regeneration.' But it is not evidence of myocardial regrowth."

Because the adult mammalian heart cannot regenerate to any significant degree, an injury, such as that caused by a heart attack, damages the muscle irrevocably and can ultimately lead to heart failure and death. Following a 2011 paper that showed newborn mice could regenerate their hearts after having a chunk removed, some scientists began speculating that if they could figure out the mechanisms behind this renewal and recapitulate them in human heart attack victims, they might be able to prevent heart failure. The researchers reasoned that determining precisely when in the first week of life this capacity ceases might enable the identification of the factors involved. It was known that heart muscle cells continue to copy their DNA for a few days after birth, so one idea was that the heart's renewal capacity might be linked to this replication.

Researchers cut out the apical tips from the hearts of newborn mice on day 1, 2, 3, 4, or 9 after birth. Three weeks later, the researchers sacrificed the mice and reexamined their hearts. Animals whose hearts were resected on day 1 showed minimal scarring and the hearts were approximately the same size and shape as those of control animals. By contrast, animals who underwent heart surgery on day 2, 3, 4, or 9 exhibited large fibrotic scars in place of regrowth. Given the different recoveries of day 1 and day 2 mice, the team looked for differences between the animals' transcriptomes. "We were actually expecting to find differences in cell cycle genes, but that was not the case. The main difference that we found was in genes related to the extracellular matrix." The group saw a general upregulation of genes for ECM components and went on to show that the ECMs of day 2 mouse hearts were approximately 50 percent stiffer than those of day 1 hearts.

To determine whether ECM stiffness and regeneration were causally linked, researchers disrupted ECM formation in developing pups. They treated the pups with β-aminopropionitrile (BAPN) - an inhibitor of the ECM cross-linking enzyme LOX - during pregnancy (via the mothers' drinking water) and for three days after birth (through the mothers' milk). As a result, three-day-old pups were able to regenerate their hearts with significantly reduced fibrosis compared with controls whose ECMs were intact. Other researchers note that the proof that these mice are actually regenerating heart tissue wasn't provided, but the team is confident: "When there is no regeneration, you can see that the heart ventricular apex is missing a bit, and is replaced by a white patch (a scar). In contrast, it is not possible to distinguish, morphologically, a heart that completely regenerated from one that was not amputated."


Fasting Reverses Age-Related Decline in Regenerative Capacity of Intestinal Stem Cells

Today I'll point out a demonstration of one of the many ways in which calorie restriction and fasting improve matters in our biology, in this case via improved stem cell function. As always it is worth bearing in mind that while forms of calorie restriction produce useful short term and long term healthy benefits in humans, they don't have anywhere near the same size of effect on life span as occurs in short-lived species such as mice. We didn't evolve to react as strongly to famines, as famines are typically a much shorter fraction of our life span in comparison to that of a mouse.

Stem cell populations, of different types for each variety of tissue in the body, support surrounding tissue by providing a supply of daughter somatic cells. As aging progresses, stem cell populations become ever less active, and this supply diminishes. Tissue function falters and eventually fails as a consequence. The evidence to date suggests that this decline is at least as much an evolved reaction to the state of damage in the body as it is dysfunction in the stem cells themselves. Numerous demonstrations show that, placed into a less damaged environment, old stem cells are just as active as young stem cells. Other lines of research have delivered signal molecules to induce old stem cells into greater activity in situ.

Is this safe? The consensus on why stem cell activity declines with age is that it balances mortality due to cancer versus mortality due to failing tissue function. Stem cells in old individuals do accumulate mutations and other forms of damage, while at the same time rising levels of inflammation and incapacity of the immune system lead to an environment that favors the development of cancer. Thus unrestricted cellular replication should have a higher risk of cancer. Evolutionary pressures have led our species to a long life span among mammals, but at the cost of a slow functional decline in later life.

Conversely, consider what has been discovered and achieved in the field of regenerative medicine: all sorts of methodologies to achieve enhanced stem cell activity. Consider the mice genetically engineered for greater levels of telomerase, in which their enhanced life span is probably mediated by increased levels of stem cell activity and tissue maintenance. The evolutionary balance appears to have a fair degree of wiggle room in which it is possible to build therapies to increase tissue maintenance without also needing to first repair the stem cells involved. The research community should still be aiming to repair and replace stem cell populations, of course - diminished numbers and cell damage become significant and problematic in very late life. This is a part of the SENS rejuvenation research agenda that, despite the high levels of funding and activity in the stem cell research community, hasn't yet made anywhere near enough material progress.

Fasting boosts stem cells' regenerative capacity

As people age, their intestinal stem cells begin to lose their ability to regenerate. These stem cells are the source for all new intestinal cells, so this decline can make it more difficult to recover from gastrointestinal infections or other conditions that affect the intestine. This age-related loss of stem cell function can be reversed by a 24-hour fast, according to a new study. The researchers found that fasting dramatically improves stem cells' ability to regenerate, in both aged and young mice.

Intestinal stem cells are responsible for maintaining the lining of the intestine, which typically renews itself every five days. When an injury or infection occurs, stem cells are key to repairing any damage. As people age, the regenerative abilities of these intestinal stem cells decline, so it takes longer for the intestine to recover. After mice fasted for 24 hours, the researchers removed intestinal stem cells and grew them in a culture dish, allowing them to determine whether the cells can give rise to "mini-intestines" known as organoids. The researchers found that stem cells from the fasting mice doubled their regenerative capacity.

Further studies, including sequencing the messenger RNA of stem cells from the mice that fasted, revealed that fasting induces cells to switch from their usual metabolism, which burns carbohydrates such as sugars, to metabolizing fatty acids. This switch occurs through the activation of transcription factors called PPARs, which turn on many genes that are involved in metabolizing fatty acids. The researchers found that if they turned off this pathway, fasting could no longer boost regeneration. They now plan to study how this metabolic switch provokes stem cells to enhance their regenerative abilities. They also found that they could reproduce the beneficial effects of fasting by treating mice with a molecule that mimics the effects of PPARs.

Fasting Activates Fatty Acid Oxidation to Enhance Intestinal Stem Cell Function during Homeostasis and Aging

Acute fasting regimens have pro-longevity and regenerative effects in diverse species, and they may represent a dietary approach to enhance aged stem cell activity in tissues. Aging in lower organisms and mammals results in the attrition of stem cell numbers, function, or both in a myriad of tissues. Such age-related changes in stem cells are proposed to underlie some of the untoward consequences of organismal aging.

It has long been appreciated that fasting has a profound impact on aging and tissue homeostasis. Our data illustrate that a 24-hr fast augments intestinal stem cell (ISC) function through the activation of fatty acid oxidation (FAO), which subsequently improves ISC activity in young and aged mice. Fasting increases FAO in ISCs by driving both a robust PPAR-mediated FAO program in ISCs and by increasing circulating levels of triglycerides and free fatty acids (FFAs) that can be then used by cells to generate acetyl-CoA for energy. Although FAO is critical for tissues with high-energy needs like skeletal and cardiac muscle, little is known about the role of FAO in ISC biology. An important question is how does increased FAO boost ISC function.

Our data indicate that aged ISCs have a reduced capacity to utilize lipids for FAO. Consistent with this notion, aging has been associated with impaired mitochondrial metabolism and FAO in a number of tissues. Because the addition of palmitic acid (PA) or induction of FAO with PPAR-delta agonists largely restores aged ISC function in our organoid assay, one possibility is that ISCs rely on FAO and a shortage in cellular energy hampers old ISC activity.

The Alzheimer's Research Community is Increasingly Supportive of the Leucadia Therapeutics Approach to the Condition

The Leucadia Therapeutics team are developing a means to restore the pace at which cerebrospinal fluid drains from the brain. Atrophy of systems of drainage with age causes metabolic wastes such as amyloid and tau to accumulate, leading to Alzheimer's disease. In the past few years, a growing number of papers have emerged in support of this class of approach to the treatment of Alzheimer's. This one is a more general example, suggesting that any means of reducing protein aggregates in cerebrospinal fluid would help - though since a simple fluid flow mechanism already exists in the body, it seems like a good idea to get that working again in older individuals rather than trying something more complex and biochemical, such as immunotherapy.

Amyloid-β (Aβ) is cleared from the brain by several independent mechanisms, including drainage to the vascular and glymphatic systems, and in situ degradation by glial cells. Astrocytes and microglia can produce Aβ degrading proteases like neprilysin, as well as chaperones involved in the clearance of Aβ. There is also a receptor mediated endocytosis, where receptors located in the surface of glial cells are involved in the uptake and clearance of Aβ. In transcytosis, Aβ is removed from interstitial fluid (ISF) across the blood brain barrier (BBB) into the systemic blood.

A perivascular pathway facilitates cerebrospinal fluid (CSF) flow through the brain parenchyma and the clearance of interstitial solutes, including Aβ. It was thought that changes in arterial pulsatility may contribute to accumulation and deposition of toxic solutes, including Aβ, in the aging brain. However, mathematical simulation showed that arterial pulsations are not strong enough to produce drainage velocities comparable to experimental observations and that a valve mechanism such as directional permeability of the intramural periarterial drainage pathway is necessary to achieve a net reverse flow.

The pathophysiology of Alzheimer's disease (AD) is characterized by the accumulation of Aβ and phosphorylated tau protein in the form of neuritic plaques and neurofibrillary tangles, respectively. Amyloid-β accumulation has been hypothesized to result from an imbalance between Aβ production and clearance. An overproduction is probably the main cause of the disease in the familial AD where a mutation in the APP, PSEN1, or PSEN2 genes is present while altered clearance is probably the main cause of the disease in sporadic AD. A good amount of studies reporting altered clearance of Aβ in AD have been published in recent years, becoming one of the hot topics in AD research today.

The different clearance systems probably contribute to varying extents on Aβ homeostasis. Any alteration to their function may trigger the progressive accumulation of Aβ, which is the fundamental step in the hypothesis of the amyloid cascade. There is a relationship between the decrease in the rate of turnover of amyloid peptides and the probability of aggregation due to incorrect protein misfolding resulting in its accumulation. As soluble molecules can move in constant equilibrium between the ISF and the CSF, Aβ monomers and oligomers can be detected in the CSF. Indeed, measuring the levels of Aβ in the CSF is one of the main proposed biomarkers already accepted in the diagnostic criteria of AD.

Different approaches have been investigated with the aim of removing brain Aβ. Among all strategies to enhance the clearance of Aβ, immunotherapy is the most explored approach so far, but has failed to show conclusive results to date. There is an urgent need to find alternative methods to achieve a depletion of Aβ in the brain. A number of studies showed that blood dialysis and plasmapheresis reduces Aβ levels in plasma and CSF in humans and attenuates AD symptoms and pathology in AD mouse models, suggesting that removing Aβ from the plasma seems to be an effective - albeit indirect - way of removing Aβ. However, there might be a much more direct way of removing Aβ from the ISF than clearing it from the plasma: clearing it from the CSF.

The "CSF-sink" therapeutic strategy consists on sequestering Aβ from the CSF. Today, we can conceive several ways of accessing the CSF with implantable devices. These devices can be endowed with different technologies able to capture target molecules, such as Aβ, from the CSF. Thus, these interventions would work as a central sink of Aβ, reducing the levels of CSF Aβ, and by means of the CSF-ISF equilibrium would promote the efflux of Aβ from the ISF to the CSF. The "CSF-sink" therapeutic strategy is expected to provide an intense and sustained depletion of Aβ in the CSF and, in turn, a steady decrease Aβ in the ISF, preventing the formation of new aggregates and deposits in the short term and potentially reversing the already existing deposits in the medium and long terms.


Suggesting that the Gut Microbiome Contributes to Atherosclerosis

Researchers here report a correlation that suggests age-related changes in gut bacterial populations may contribute to the development of atherosclerosis. This is a condition in which damaged lipids in the bloodstream produce an inflammatory overreaction in blood vessel walls. The macrophages that arrive to help clear up damage are overcome and die, producing more inflammation and cellular debris. Over years this grows into fatty plaques that narrow and weaken blood vessels, eventually resulting in catastrophic structural failure or blockage. How might bacteria in the gut contribute to this process? The most plausible mechanisms involve secretion of compounds that encourage chronic inflammation or oxidative stress, changing cell behavior in ways that drives the creation of more of the damaged lipids that spur atherosclerosis. While a range of evidence supports such a role for the compounds mentioned below, this is an area of research in which much remains to be conclusively proven.

Researchers have shown a novel relationship between the intestinal microbiome and atherosclerosis, one of the major causes of heart attack and stroke. This was measured as the burden of plaque in the carotid arteries. In order to understand the role that bacteria in the gut may play in atherosclerosis, the researchers examined blood levels of metabolic products of the intestinal microbiome. They studied a total of 316 people from three distinct groups of patients - those with about as much plaque as predicted by traditional risk factors, those who seem to be protected from atherosclerosis because they have high levels of traditional risk factors but normal arteries, and those with unexplained atherosclerosis who don't have any traditional risk factors but still have high levels of plaque burden.

"What we found was that patients with unexplained atherosclerosis had significantly higher blood levels of these toxic metabolites that are produced by the intestinal bacteria." The researchers looked specifically at the metabolites TMAO, p-cresyl sulfate, p-cresyl glucuronide, and phenylacetylglutamine, and measured the build-up of plaque in the arteries using carotid ultrasound. The study noted that these differences could not be explained by diet or kidney function, pointing to a difference in the make-up of their intestinal bacteria. "There is growing consensus in the microbiome field that function trumps taxonomy. In other words, bacterial communities are not defined so much by who is there, as by what they are doing and what products they are making."


Higher Levels of Progerin are Found in Cardiomyopathy Patients

Hutchinson-Gilford progeria syndrome (HGPS), or simply progeria, is a rare genetic condition that presents the superficial appearance of greatly accelerated aging. It isn't in fact accelerated aging, but rather one specific form of molecular damage run amok, causing severe and increasing dysfunction in near all cells. Normal aging is a collection of many varied forms of molecular damage that eventually cause severe and increasing dysfunction in near all cells. The consequences of a failure of any given population of cells or an organ to function correctly can appear superficially similar even if the causes are not the same, but as soon as one digs in to the details, the different mechanisms become evidence and significant.

Soon after the turn of the century, the cause of progeria was identified: a mutation in the LMNA gene that gives rise to a broken protein now called progerin. The normal, unbroken form of this protein, lamin A, is a vital part of the internal structure of a cell, and once once that structural support falters, all of the other finely balanced mechanisms begin to fail as well. Soon thereafter, it was discovered that progerin can also be found in small amounts in older genetically normal individuals, and for many years it has been an open question as to whether progerin plays a significant role in the degeneration of normal aging. Given that it exists, it is certainly causing harm, but the size of the effect is key: there are plenty of areas in the biochemistry of aging where it might be argued that observed forms of damage and change do not rise to the level of being significant causes of dysfunction, disease, and mortality. We can worry about them after every other problem is fixed.

The paper here identifies a patient group suffering from an age-related disease in which progerin is elevated in comparison to their healthier peers. This is an intriguing addition to what is known of progerin in normal aging. It is still a long way from being able to assign numbers to the position of progerin in a hierarchy of cell damage, especially given that the research community has yet to achieve this for any of the other root causes of aging, but it is a small step along that road. It also suggests that a more careful survey of age-related disease might turn up other conditions in which progerin may be either a contributing factor, or a consequence of other disease processes.

Upregulation of the aging related LMNA splice variant progerin in dilated cardiomyopathy

Age is a major cardiovascular risk factor including cardiovascular disease. Therefore, elucidating aging-related processes might lead to the identification of novel treatment options for heart failure, which has a prevalence of 1-2% in the adult population in developed countries and is a growing health care problem worldwide. Premature aging-like syndromes like Hutchinson-Gilford progeria syndrome (HGPS) have been investigated to achieve a better understanding of pathophysiological aging processes. HGPS is based on mutations affecting the proper encoding and further processing of lamin A an important protein in the nucleus of eukaryotic cells resulting in misprocessed lamin A (progerin) which also plays an important role in normal ageing.

Lamin A is an intermediate filament protein which is involved in forming a filamentous meshwork between the chromatin and the nuclear membrane. It is very important to keep the nuclear envelope upright regulating important processes like DNA replication, DNA repair, and RNA transcription. In 90% of the cases in HGPS a point mutation in the LMNA A gene results in the production of a truncated prelamin A protein, also called progerin. Consequently, the protein cannot be processed to functional lamin A, causing structural and functional nuclear abnormalities.

With time proceeding progerin accumulates in the nucleus and not only alters the structure of the nuclear lamina but also negatively influences the stiffness and mechanochemical properties of the nucleus. Patients with HGPS develop severe cardiovascular morbidities like atherosclerosis and heart failure and die as teenagers due to stroke or myocardial infarction. Toward the end of life HGPS patients suffer from cardiomegaly and cardiac dilatation. It has been shown that low levels of progerin are expressed in non HGPS-cells and that a positive correlation exists between accumulation of progerin in the nucleus and the process of ageing. However, the role of progerin in human dilated cardiomyopathy (DCM), a major reason of severe heart failure, has never been investigated so far.

Here we provide first experimental evidence that progerin, associated with premature aging in HGPS is upregulated in human DCM. Progerin mRNA expression in the heart was strongly significantly correlated with left ventricular remodeling. Although there was a weak positive correlation between age and progerin mRNA expression, statistical testing revealed no significant differences. These data suggest that not the age of the heart per se but rather the process of "myocardial aging" defined by a progressive deterioration in cellular and organ function with time is associated with increased levels of progerin mRNA.

It is known that prelamin A accumulation plays a key role in aging in several tissues, including the vasculature and is discussed as a marker for vascular aging. However, it is currently unknown whether this is relevant in myocardial aging, too. Since LMNA gene mutations are causally involved in patients with idiopathic dilated cardiomyopathy (3.6%) and familial dilated cardiomyopathy (7.5%), we hypothesized that accumulation of progerin in non-HGPS individuals in the heart may as well be involved in the progression of DCM. To our knowledge we show for the first time that progerin is upregulated in human DCM hearts suggesting that accumulation of progerin (prelamin A) could be involved in the progression of DCM and myocardial aging.

How Many Years of Additional Life Expectancy Does a Healthy Lifestyle Provide?

What does a healthy lifestyle achieve for life expectancy? It is surprisingly hard to answer that question for humans. Researchers can't construct carefully cultivated lifestyle choice groups and follow them from birth to death. Instead, messy and imperfect vaults of epidemiological data must be fed into complicated statistical machinery, using strategies that are, at the end of the day, guided by a healthy dose of intuition and common sense. Different groups can and do produce widely different answers to questions regarding additional years added by diet, exercise, or other factors. One has to survey the field in aggregate, averaging over dozens of studies to try to get an idea of what might or might not be the reality. So take this one study in that context - the number produced at the end is large in comparison to other studies I've seen in past years, but the authors are trying to consider all of the major effects rather than just one.

Maintaining a healthy lifestyle, including eating a healthy diet, regular exercise, and not smoking, could prolong life expectancy at age 50 by 14 years for women and just over 12 years for men, according to new research. Heart disease and stroke are major contributors to premature death in this country, with 2,300 Americans dying of cardiovascular disease each day, or one death every 38 seconds. Researchers point out that the U.S. healthcare system focuses heavily on drug discovery and disease management; however, a greater emphasis on prevention could change this life expectancy trend.

To quantify the effects of prevention, researchers analyzed data from two major ongoing cohort studies that includes dietary, lifestyle and medical information on thousands of adults in the Nurses' Health Study and the Health Professionals Follow-up Study. These data were combined with National Health and Nutrition Examination Survey (NHANES) data, as well as mortality data from the Centers for Disease Control and Prevention (CDC), to estimate the impact of lifestyle factors on life expectancy in the U.S. population. Specifically, they looked at how the following five behaviors affected a person's longevity: not smoking, eating a healthy diet (diet score in the top 40 percent of each cohort), regularly exercising (30+ minutes a day of moderate to vigorous activity), keeping a healthy body weight (18.5-24.9 kg/m), and moderate alcohol consumption (5-15 g/day for women, 5-30 g/day for men).

Over the course of nearly 34 and 27 years of follow-up of women and men, respectively, a total of 42,167 deaths were recorded, of which 13,953 were due to cancer and another 10,689 were due to cardiovascular disease. Following all five lifestyle behaviors significantly improved longevity for both men and women. Compared with people who didn't follow any of the five lifestyle habits, those who followed all five were 74 percent less likely to die during the follow-up period; 82 percent less likely to die from cardiovascular disease and 65 percent less likely to die from cancer. There was a direct association between each individual behavior and a reduced risk of premature death, with the combination of following all five lifestyle behaviors showing the most protection.

Between 1940 and 2014, Americans' life expectancy at birth rose from around 63 years to nearly 79 years. However, researchers believe the improvement of life expectancy would be even larger without the widespread prevalence of obesity - a known risk factor for heart disease, stroke, and premature death. "It is critical to put prevention first. Prevention, through diet and lifestyle modifications, has enormous benefits in terms of reducing occurrence of chronic diseases, improving life expectancy as shown in this study, and reducing healthcare costs."


Longevity Industry Landscape Overview Volume II: The Business of Longevity

The second volume has been published in the Longevity Industry Landscape Overview compendium. The various authors and funding organizations aim to survey all of the participants in the present scientific and business communities focused on the treatment of aging as a medical condition. The focus is on breadth of coverage rather than depth, so this is another sizable document. Once past the introductory sections, most of it is useful for reference rather than reading. But you should still take a look at those opening chapters.

"The majority of politicians and the general public are unaware of the tremendous potential benefits of regenerative medicine. They fail to grasp the profound implications that extended longevity could have on the global economy, on their respective nation's economic survival, and on their own lifespan and health." When did geroscience become a science? When did longevity become an industry? When did it become a 'business'? For almost all of recorded history, it has been a fantasy. During the first half of the 20th century, healthy life extension meant either devising specialised techniques for treating specific diseases or nursing and elderly care. This remained the case throughout both the scientific and industrial revolutions, until the 1940s, when the metabolic processes of aging became an area of modest scientific interest.

Thus began what would eventually become modern geroscience. It retained something of a fringe reputation even into the 21st century. Driven by academic curiosity and the vague hope of modest biomedical intervention, the science plodded along, gaining occasional insights for half a century under the title of 'biomedical gerontology'. As biomedical gerontology advanced, parallel technologies such as regenerative medicine and gene therapy, which dealt with the constituent phenomena of aging but using the language of engineering, had been been coming of age. In the mid-2000s technologists began to notice that the science was ahead of the technology and that the identification of the problem was nearly complete. The solution lay in the technology, which was then, as now, woefully underdeveloped.

This was the period when the concept of 'rejuvenation biotechnology' emerged - not an industry unto itself but an arm of regenerative medicine. Propped up by various non-profits, rejuvenation biotechnology staggered forward into the second decade of the century. In 2013 Google launched the healthcare venture Calico (the 'California Life Company', whose stated remit is healthy human life extension by technological means), an act which dramatically raised the profile of healthy life extension as a legitimate, technological pursuit, thereby bringing the notion of a longevity industry from the fringe to the cutting edge of biomedicine. If 2013 raised the science of longevity out of obscurity, 2017 did the same for the industry, marking the end of a long winter of non-investment in longevity technologies.

The net benefit of all these developments has been that those initially highly skeptical of the formation of a veritable, scientifically validated and profitable longevity industry began to sit up and take notice. The 2015 investment boom was followed by another boom in 2017 in longevity biomedicine. This was the period in which investors finally began to equate rejuvenation with repair. That is, with regenerative medicine. After a long period of dismissal, an increasing number of prominent scientists have come to work for and publicly endorse efforts to enable and accelerate progress in this area, changing the face of medicine and improving the prospects for human lifespan - and healthspan. This, however, has not yet become a fully fledged commercial industry.


Gene Therapy to Enhance Proteosomal Activity Slows Retinal Degeneration in Mice

Many of the methods by which aging can be modestly slowed in laboratory species are characterized by increased cellular housekeeping: more repair, more clearance of broken molecular machinery, more removal of metabolic waste. The extended life span produced by calorie restriction appears to depend on this increase: it doesn't happen in mice in which housekeeping processes are disabled. Most of the work on cellular housekeeping in aging is focused on autophagy, responsible for removing protein aggregates and cellular structures. The proteasome is a part of a separate system of housekeeping that deals with broken or otherwise unwanted proteins. (Though it can be debated as to just how separate these two systems actually are in practice - everything inside a cell connects to everything else in some way).

With this in mind, I'll point out a paper that caught my eye today, in which researchers genetically enhance proteasomal activity in a mouse model of retinal degeneration. They show that the mice are better able to resist the loss of retinal cells: the cells are more robust in the face of damaged and harmful proteins that accumulate either with age or because of inherited mutations that disrupt correct cellular function. This is more interesting for the demonstration of the possibility rather than the results in this particular case. Absent side-effects, permanently improved cellular housekeeping would be a desirable enhancement technology, something that might reproduce many of the long-term health benefits of calorie restriction and exercise.

The work in this paper for the proteasome is analogous to the LAMP2A gene therapy used in mice to enhance autophagy in the liver some years ago. That slowed the impact of aging on tissue function by making cells more resilient and capable of carrying out their assigned tasks. Both that and this proteasomal enhancement involve increasing the production of one of the component parts of the housekeeping system, and that is apparently enough to boost overall activity and efficiency. All forms of cellular housekeeping decline with age, an outcome that is caused by fundamental forms of damage, such as the buildup of forms of metabolic waste that our biochemistry cannot effectively break down. Enhancing housekeeping operations without dealing with that damage is essentially compensatory, an approach of limited effectiveness, given that the damage remains to cause all of its other consequences. It may still be cost-effective enough to pursue, provided it isn't pursued to the exclusion of addressing the underlying cell and tissue damage that causes aging and all of its issues.

Strategy prevents blindness in mice with retinal degeneration

More than 2 million people worldwide live with inherited and untreatable retinal conditions, including retinitis pigmentosa, which slowly erodes vision. Developing treatments is challenging for scientists, as these conditions are caused by more than 4,000 different gene mutations. But many of these mutations have something in common - a propensity for creating misfolded proteins that cells in the eye can't process. These proteins build up inside cells, killing them from the inside out.

Now scientists have shown that boosting the cells' ability to process misfolded proteins could keep them from aggregating inside the cell. The researchers devised and tested the strategy in mice, significantly delaying the onset of blindness. Their approach potentially could be used to prevent cell death in other neurodegenerative diseases, such as Huntington's, Parkinson's and Alzheimer's.

The researchers focused on the proteasome: machinery inside all cells that eliminates misfolded proteins. You can compare the barrel-shaped structure to a paper shredder, with the cutting elements hidden inside. Misfolded proteins must pass through a "lid" on the shredder to be processed, but cells in diseased mice do not have enough lids, enabling the buildup of the damaged proteins. Instead of trying to alter the shredders, researchers genetically increased the quantities of lids for the shredders, allowing cells to process more misfolded proteins. In trials, mice with added proteasome lids retained four times the number of functional retinal cells by adulthood than mice with the same form of retinitis pigmentosa, which went blind as adults.

Increased proteasomal activity supports photoreceptor survival in inherited retinal degeneration

Studies of animal models of retinitis pigmentosa (RP) have revealed a number of common pathological conditions: oxidative stress, unfolded protein response, retinoid cytotoxicity, iron toxicity, and aberrant phototransduction. Our recent work demonstrated that another major cellular stress factor prevalent in a broad spectrum of mouse RP models is the insufficient capacity of the ubiquitin-proteasome system to process misfolded or mistargeted proteins in affected cells. We further demonstrated that the severity of photoreceptor retinal degeneration correlates with the degree of misfolded protein production. Conversely, genetic manipulation reducing the proteolytic capacity of proteasomes evoked RP-like pathology in otherwise normal retinas.

The goal of the present study was to determine whether survival of degenerating photoreceptors could be supported by enhancing the proteolytic capacity of their proteasomes. We aimed to increase the proteasome activity in these cells using two independent genetic strategies and found that the strongest effect was achieved by overexpressing the PA28α subunit of the 11S proteasome cap. We also show that the underlying mechanism is based primarily on the stimulation of ubiquitin-independent protein degradation. Breeding PA28α-overexpressing mice with two mouse models of photoreceptor degeneration results in a delay of disease progression.

Promising Long Term Results in Stem Cell Therapy for Peripheral Artery Disease

Five years ago, a small group of patients who had exhausted other treatment options for their peripheral artery disease were treated with stem cells. Researchers have followed the patients since then, and here report on the long term results - they are promising. This is also the case for a range of other comparatively simple stem cell transplant therapies, now that the research and medical communities have had years to practice and refine the methodologies involved.

A long-term study of patients who received stem cells to treat angiitis-induced critical limb ischemia (AICLI) shows the cells to be both safe and effective. The study could lead to an option for those who suffer from this serious form of peripheral arterial disease (PAD). AICLI is caused by an inflammation of the blood vessels that leads to a severe blockage in the arteries of the lower or upper extremities. It causes severe pain and impaired mobility, and can even lead to amputation and death. While endovascular and surgical reconstruction are the mainstream treatments for critical limb ischemia (CLI), these classical treatments are unfeasible in approximately 15 to 20 percent of patients.

Stem cell therapy is a promising option for these otherwise no-option CLI patients. As one of the promising stem cell therapies, purified CD34+ cell transplantation (PuCeT) has shown favorable short-term results, but prior to this new study no one had looked at its long-term outcome. Researchers tracked 27 AICLI patients for five years after each had received an intramuscular injection of PuCeT to treat their disease. The primary endpoint - major-amputation-free survival rate - as well as secondary endpoints such as peak pain-free walking time and the scale of the patient's pain, were routinely evaluated during the five-year follow-up period.

The results showed that the major-amputation-free survival rate of these patients was 88.89%, the pain free walking time increased nearly 6-fold and the level of pain they experienced was reduced by more than half. Notably, in 17 patients (65.38 percent) not only were their limbs saved, but they also fully recovered their labor competence and returned to their original jobs by week 260.


Inflammatory Necroptosis Increases with Aging and is Slowed by Calorie Restriction

Calorie restriction modestly slows near every measure of aging, so it isn't surprising to see it in action here. Putting that to one side, the interesting part of this paper is the new data on necroptosis, a form of programmed cell death recently enough discovered to receive little attention in comparison to other, similar cell fates. Necroptosis is inflammatory, and rising levels of chronic inflammation occur with aging, driving progression of many of the common age-related diseases. To what degree is this caused by necroptosis versus malfunction in the immune system versus senescent cells versus other causes? Time will tell. Based on research from past years, I'd guess that necroptosis will turn out to be significant as one of the mediating mechanisms linking excess fat tissue with chronic inflammation - there is evidence for cellular debris from dead fat cells to produce that outcome.

Aging is characterized by the progressive increase in chronic, low-grade inflammation termed "inflammaging," which is believed to play an important role in the mechanism underlying aging. Necroptosis is a newly identified form of cell death that initiates an inflammatory process when the dying cells release cell debris and self-molecules, that is, damage-associated molecular patterns, DAMPs or alarmins. DAMPs are a major activator of NLRP3 inflammasome that triggers maturation of interleukin-1β (IL-1β), and NLRP3 inflammasome activation is one of the mechanisms that induces low-grade chronic inflammation with age. Several studies show that blocking necroptosis either genetically or pharmacologically dramatically reduces inflammation in a variety of mouse models. In addition, blocking/reducing necroptosis appears to have an impact on the aging of the male reproductive system and increases the lifespan of ApoE knockout mice and G93A transgenic mouse model of ALS. Necroptosis also appears to play a role in neuron loss in Alzheimer's disease.

To determine whether necroptosis might be a factor in inflammaging, we determined whether necroptosis increases with age and whether it was attenuated by dietary restriction (DR), which retards aging and reduces the increase in chronic inflammation. We measured necroptosis in epididymal white adipose tissue (eWAT), which is a visceral fat depot that is associated with the greatest inflammatory cytokine production, compared to other fat depots, and inguinal WAT (iWAT), which is a subcutaneous fat depot less inflammatory in nature. The level of P-MLKL, a well-accepted marker of necroptosis, was 2.7-fold greater in eWAT of old mice (25-29 months) compared to adult mice (9 months), and DR (started at 4 months of age) reduced P-MLKL to a level similar to adult mice.

We next determined whether the increase in necroptosis in eWAT was associated with increased inflammation. DAMPs produced by necroptosis are reported to increase the release of pro-inflammatory cytokines from innate immune cells through the activation of NF-κB. Therefore, we measured activation of NF-κB in eWAT by the phosphorylation of NF-κB. The level of phospho-NF-κB normalized to NF-κB was 1.4-fold greater in eWAT of old mice compared to adult mice, and DR reduced phospho-NF-κB to a level similar to adult mice.

In summary, our study is the first to demonstrate that biomarkers of necroptosis increase with age. The observation that the changes in necroptosis in eWAT with age and DR are paralleled by changes in the expression of pro-inflammatory cytokines support the possibility that necroptosis may play a role in the age-related increase in chronic inflammation in visceral fat, and possibly inflammaging in the whole animal. Using genetic and pharmacological manipulations which block necroptosis, it will be possible to determine whether the age-related increase in necroptosis causes the increased inflammation observed with age.


How to Plan and Carry Out a Simple Self-Experiment, a Single Person Trial of a Mitochondrially Targeted Antioxidant

This lengthy post walks through the process of setting up and running a self-experiment - a trial of one - with one of the various established mitochondrially targeted antioxidant compounds. Metrics are assessed beforehand and afterwards in order to shed some light on whether or not it worked, in the sense of improving one or more measures of cardiovascular health. The outline here is informed by a recently published small human trial of MitoQ, but cutting down the assessments to those that are cost-effective, easily carried out, and available without the aid of a physician.

The purpose in publishing this outline is not to encourage people to immediately set forth to follow it. This post, like others in this series, is intended to illustrate how to think about self-experimentation in the matter of interventions that might help to improve health or turn back aspects of aging: set your constraints; identify likely approaches; do the research to fill in the necessary details; establish a plan of action; perhaps try out some parts of it in advance, such as the measurement portions, as they never quite work as expected; and most importantly identify whether or not the whole plan is worth actually trying, given all that is known of the risks involved. Ultimately that must be a personal choice.


Why Self-Experiment with Mitochondrially Targeted Antioxidants?

Ordinary antioxidant supplements are thought to be, on balance, modestly harmful to long term health. They block signaling that is important to the beneficial response to exercise, for example. Mitochondrially targeted antioxidants, on the other hand, have been shown to slightly slow aging in short-lived species, and improve measures of health along the way. They also appear to be a viable treatment for some localized inflammatory conditions. The theory here is that mitochondria generate oxidative molecules in the normal course of operation that cause damage within the mitochondria themselves, and that in turn leads to dysfunctional cells in which the mitochondria produce a vastly greater amount of oxidative molecules. Delivering a constant supply of mitochondrially targeted antioxidants may either slow down the pace at which mitochondria damage themselves, or dampen the consequences of cells overtaken by damaged mitochondria, or both.

One of those consequences is the bulk export of oxidative molecules into surrounding tissues and the bloodstream, where they react with lipids. Oxidized lipids can cause further harm in all sorts of cellular processes, but of particular interest is the development of atherosclerosis. Oxidized lipids can cause inappropriate inflammatory reactions in blood vessel walls, and some forms can also cause the cells responding to that inflammation to become overwhelmed and die. This is how the fatty plaques of atherosclerosis form, then grow to weaken and narrow major blood vessels. Statin drugs, that reduce blood cholesterol, succeed in slowing atherosclerosis because they reduce the amount of oxidized lipids in the course of reducing the amount of all lipids.

Further, some degree of dysfunction in the vascular smooth muscle responsible for blood vessel contraction and dilation is thought to be caused by rising levels of oxidative stress in aging - too many dysfunctional mitochondria, too many oxidative molecules. This contributes to vascular stiffness and consequent hypertension, cardiovascular disease, and so forth. Suppressing the oxidative consequences of malfunctioning mitochondria may help here as well.

Mitochondrially targeted antioxidants don't solve the roots of these problems. At best, they somewhat compensate or attenuate ongoing mechanisms. They are cheap, however, and if they can produce effects on risk factors for cardiovascular disease that are, say, somewhere in the same order of magnitude as those achieved by statins or drugs that control blood pressure, with minimal side-effects, then they may well be worth using.


While some mitochondrially targeted antioxidants are approved by regulators, widely used, and readily available, or otherwise come with an adequate set of human data to judge risk, one must still think about personal responsibility in any self-experiment. Firstly, read the relevant papers on the mitochondrially targeted antioxidant of choice - its effects, side-effects, and dosages - and make an individual decision on risk and comfort level based on that information. This is true of any supplement, whether or not approved for use. Do not trust other opinions you might read online: go to the primary sources, the scientific papers, and read those. Understand that where the primary data is sparse, it may well be wrong or incomplete in ways that will prove harmful. Also understand that older physiologies can be frail and vulnerable in ways that do not occur in younger people and that are sometimes not well covered by the studies.

Secondly, while work on mitochondrially targeted antioxidants hasn't moved all that rapidly over the past decade, it does move. This post will become outdated in its specifics at some point, as new knowledge and new mitochondrially targeted antioxidants arrive on the scene. Nonetheless, the general outline should still be a useful basis for designing new self-experiments involving later and hopefully better compounds, as well as tests involving more logistical effort.

Lastly, obtaining and using arbitrary compounds not yet approved in your country for human use - such as SkQ1 - in the manner described here is potentially illegal: not yet being a formally registered medical treatment in all jurisdictions, it falls into a nebulous area of regulatory and prosecutorial discretion as to which of the overly broad rules and laws might apply. In effect it is illegal if one of the representatives of the powers that be chooses to say it is illegal in any specific case, and there are few good guidelines as to how those decisions will be made. The clearest of the murky dividing lines is that it is legal to sell such compounds for research use, but illegal to market and sell them for personal use in most circumstances. This is very selectively enforced, however, and reputable sellers simply declare that their products are not for personal use, while knowing full well that this is exactly what their customers are doing in many cases.

Choosing to purchase and use SkQ1 would therefore likely be a matter of civil disobedience, as is the case for anyone obtaining medicines or potential medicines outside the established national system of prescription and regulation. People are rarely prosected for doing so for personal use in the US - consider the legions of those who obtain medicines overseas for reasons of cost, despite the fact that doing so is illegal - but "rarely" is not "never." If you believe that the law is unjust, then by all means stand up against it, but accept that doing so carries the obvious risks of arrest, conviction, loss of livelihood, and all the other ways in which the cogs of modern society crush those who disagree with the powers that be.

Choosing a Mitochondrially Targeted Antioxidant

There are two mitochondrially targeted antioxidants worth considering: MitoQ and SkQ1. These have the greatest human usage and data. A third, SS-31, also has useful data, but must be injected. It may well be that one or another of these compounds is significantly better than the others (and SkQ1 would probably be the one, if so), but there is no compelling reason to pick an injected compound over one that can be taken orally for the purposes of this self-experiment. Injections require a great deal more logistical organization than simply taking a pill.

Establishing Dosages

The only definitive way to establish a dosage for a supplement pharmaceutical in order to achieve a given effect is to run a lot of tests in humans. Testing in mice can only pin down a likely starting point for experiments to determine a human dose, but the way in which you calculate that starting point is fairly well established for most cases. That established algorithm is essentially the same for most ingested and intravenously (or intraperitoneally in small animals) injected medicines, but doesn't necessarily apply to other injection routes. The relationship between different forms of injection, dosage, and effects is actually a complicated and surprisingly poorly mapped topic, and we'll set that to one side here. Some compounds - as always - are exceptions to the rule, and the only way that scientists discover that any specific compound is an exception is through testing at various doses in various species.

Fortunately, some mitochondrially targeted antioxidants do have human data, so guesstimating an initial dose based on a mouse study can be skipped. Just use the amounts from the human studies. If lacking that data, the steps to figure out a suitable starting point for a human test based on data from a mouse study are as follows: firstly read the mouse studies for the compound in question, in order to find out how much was given to the mice and for how long. Doses for most ingested pharmaceuticals of interest will usually be expressed in mg/kg. Secondly apply a standard multiplier to scale this up to human doses, which you can find in the open access paper "A simple practice guide for dose conversion between animals and human". Do not just multiply by the weight of the human in kilograms - that is not how this works. The relative surface area of the two species is the more relevant scaling parameter. Read the paper and its references in order to understand why this is the case. Again, note that the result is only a ballpark guess at a starting point in size of dose. The duration of treatment translates fairly directly, however. For the period of treatment, start with the same number of doses, spacing of doses, and duration as takes place in the animal study.


All the work is already done in this case. The 2018 MitoQ human study used a daily 20mg dose for six weeks, and that seems a good place to start.


SkQ1 is a little more challenging, in that it was initially approved by regulators for the treatment of inflammatory eye disease under the name Visomitin; most of the human data focuses on delivery via eye drop. Dosage there isn't relevant at all to the ingested pill scenario, which is still earlier in the regulatory process. So retreating to one of the mouse life span studies, we find that the daily dose of SkQ1, delivered in drinking water, was in the 0.7-1.0 μmol/kg range. Scaling this up to a 60kg human comes to 3.5-5.0 μmol per day. The study ran for more than 150 days of treatment, as it was assessing life span, but mirroring the six weeks of the MitoQ study above seems reasonable when looking for short term effects.

Visomitin eye drops come in a 5ml container, with 0.155 mcg/ml dilution. To convert between micrograms (mcg or μg) and micromoles (μmol), one needs the molecular weight of SkQ1, which is where resources such as PubChem come in handy. That gives the figure of 617.608 g/mol. Thus a daily dose of 5μmol = 0.000005 x 617.608 = 0.0031g = 3100mcg = 3.1mg. Which suggests that people buying Visomitin to put in their drinking water are wasting their time - it is intended for point administration to a very small area of the body, the eye.

Over 6 weeks of daily administration, the above means a supply of about 130mg is needed.

Verify All of the Above

Assume that anything written anywhere other than the primary materials might be incorrect or misleading. Do not take my word for any of the above information; chase down the primary sources, run the numbers, and make the judgement calls yourself.

Obtaining Mitochondrially Targeted Antioxidants


MitoQ is cheap and readily available from MitoQ Limited via any number of reputable online storefronts. It really isn't worth the effort to find another, cheaper supplier, and then be tasked with verifying the quality of the product batch. Just buy it from a store.


Given a few years, pill forms will be readily available at a useful dosage for oral ingestion. For now, however, it is a matter of finding a manufacturer or supplier in the global marketplace, and then validating the product when it arrives. For individuals without suitable connections, the easiest way to obtain compounds that are not yet mass manufactured is to order them from manufacturers in China or other overseas locations.

As noted at the outset of this post, efforts to obtain, ship, and use a compound yet to be approved for human use in your country, such as SkQ1, may be to some degree illegal - it would be an act of civil disobedience carried out because the laws regarding these matters are unjust, albeit very unevenly enforced. Many people regularly order pharmaceuticals from overseas, with and without prescriptions, for a variety of economic and medical reasons, and all of this is illegal. The usual worst outcome for individual users is intermittent confiscation of goods by customs, though in the US, the FDA is actually responsible for this enforcement rather than the customs authorities. Worse things can and have happened to individuals, however, even though enforcement is usually targeted at bigger fish, those who want to resell sizable amounts of medication on the gray market, or who are trafficking in controlled substances. While the situation with an arbitrary compound such as SkQ1 isn't the same from a regulatory perspective, there is a fair amount written on the broader topic online, and I encourage reading around the subject.

Open a Business Mailbox

A mailbox capable of receiving signature-required packages from internal shipping concerns such as DHL and Fedex will be needed. Having a business name and address is a good idea. Do not use a residential address.

Use Alibaba to Find Manufacturers

Alibaba is the primary means for non-Chinese-language purchasers to connect to Chinese manufacturers. The company has done a lot of work to incorporate automatic translation, to reduce risk, to garden a competitive bazaar, and to make the reputation of companies visible, but it is by now quite a complicated site to use. It is a culture in and of itself, with its own terms and shorthand. There are a lot of guides to Alibaba out there that certainly help, even if primarily aimed at retailers in search of a manufacturer, but many of the specific details become obsolete quickly. The Alibaba international payment systems in particular are a moving target at all times: this year's names, user interfaces, and restrictions will not be the same as next year's names, user interfaces, and restrictions.

Start by searching Alibaba for suppliers of interest. There are scores of resellers and manufacturing biotech companies in China for any even somewhat characterized supplement, pharmaceutical, or candidate pharmaceutical. Filter the list for small companies, as larger companies will tend to (a) ignore individual purchasers in search of small amounts of a compound, for all the obvious economic reasons, and (b) in any case require proof of all of the necessary importation licenses and paperwork. Shop around for prices - they may vary by an order of magnitude, and it isn't necessarily the case that very low prices indicate a scam of some sort. Some items are genuinely very cheap to obtain via some Chinese sources.

Many manufacturers will state that they require a large (often ridiculously large) minimum order; that can be ignored. Only communicate with gold badge, trade assurance suppliers with several years or more of reputation and a decent response rate. Make sure the companies exist outside Alibaba, though for many entirely reliable Chinese businesses there are often sizable differences between storefronts on Alibaba, real world presence, and the names of owners and bank accounts. Use your best judgement; it will become easier with practice.

Arrange Purchase and Shipping via Alibaba

Given the names of a few suppliers, reach out via the Alibaba messaging system and ask for a quote for a given amount of the compound in question. Buy twice what you'll think you need, as some of it will be used to validate the identity and quality of the compound batch, and buy that much from at least two different suppliers present in widely separated regions. Payment will most likely have to be carried out via a wire transfer, which in Alibaba is called telegraphic transfer (TT). Alibaba offers a series of quite slick internal payment options that can be hooked up to a credit card or bank account, but it is hit and miss whether or not those methods will be permitted for any given transaction. Asking the seller for a pro-forma invoice (PI), then heading to the bank to send a wire, and trusting to their honesty is good enough for low cost transactions. It should work just fine when dealing with companies that have a long-standing gold badge.

To enable shipping with tracking via carriers such as DHL, the preferred method of delivery for Chinese suppliers shipping to the US or Europe, you will need to provide a shipping address, email address, and phone number. Those details will find their way into spam databases if you are dealing with more than a few companies, and will be, of course, sold on by Alibaba itself as well. Expect to see an uptick of spam after dealing with suppliers via Alibaba, so consider using throwaway credentials where possible.

Chinese manufacturers active on Alibaba are familiar with international shipping practices, and smaller companies will, on their own initiative, apply whatever description to packages will most likely get it past customs. Since declared pharmaceuticals may well be taken aside and confiscated, the description will therefore not involve pharmaceuticals. This is as much motivated by dealing with customs at the Chinese end as pushing things past the US authorities; it is again a form of widespread civil disobedience that reflects a popular disdain for petty laws and regulators where they act as impediments to useful activity.

Storage of Mitochondrially Targeted Antioxidants

Both MitoQ and SkQ1 have a long shelf life of years if kept in a freezer. For more convenient use over shorter periods of time, say a few weeks to a few months, should be kept in the dark in a refrigerator for shorter periods of time. SkQ1 is less resilient than MitoQ and will degrade after few weeks at room temperature.

Validating the Purchased Mitochondrially Targeted Antioxidants

While it is reasonable to trust MitoQ Limited to deliver what was ordered, that may not be the case for other sources. A compound may have been ordered, but that doesn't mean that what turns up at the door is either the right nondescript powder or free from impurities or otherwise of good quality. Even when not ordering from distant, infrequent suppliers, regular testing of batches is good practice in any industry. How to determine whether a compound is what it says it is? Run the compound through a process of liquid chromatography and mass spectrometry, and compare the results against the standard data for a high purity sample of that compound. Or rather pay a small lab company to do that.

Obtain the Necessary Equipment

Since this process will involve weighing, dividing up, and shipping powders in milligram amounts, a few items will be necessary: spatulas or scoops for small amounts of a substance; a reliable jeweler's scale such as the Gemini-20; sealable vials; small ziplock bags; labels; and shipping and packing materials. All of these are easily purchased online. The recommended shipping protocol is to triple wrap: a labelled vial, secured within a ziplock bag and tape, and then enclosed within a padded envelope.

Use Science Exchange to Find Lab Companies

Science Exchange is a fairly robust way to identify providers of specific lab services, request quotes, and make payments. Here again, pick a small lab company to work with after searching for LC-MS (liquid chromatography and mass spectrometry) services. Large companies will want all of the boilerplate registrations and legalities dotted and crossed, and are generally a pain to deal with in most other ways as well. Companies registered with Science Exchange largely don't provide their rates without some discussion, but a little over $100 per sample is a fair price for LC-MS to check the identity and purity of the compound.

Work with the Company to Arrange the Service

The process of request, bid, acceptance, and payment is managed through the Science Exchange website, with questions and answers posted to a discussion board for the task. Certainly ask if you have questions; most providers are happy to answer questions for someone less familiar with the technologies used. Service providers will typically want a description of the compounds to be tested and their standard data sheets, as a matter of best practice and safety. It is good enough to provide the name for established pharmaceuticals, as the data sheets, mass spectrometry profiles, and other detailed information are freely available online from databases such as DrugBank.

Ship the Samples

Measure out a small amount (1mg is more than enough) from each separate order as a distinct sample, label it carefully, make sure you have a record linking the sample label to the specific supplier, and package it up. More in the sample is better than less, as several attempts might be needed to get a good result out of the machines used, but each attempt really only needs a very tiny amount of the compound. Ship the sample via a carrier service such as DHL, UPS, or FedEx. Some LC-MS service companies may provide shipping instructions or recommendations. These are usually some variety of common sense: add a description and invoice to the package; reference the order ID, sender, and receiver; clearly label sample containers; and package defensively with three layers of packing; and so forth.

Examine the Results

Once the LC-MS process runs, the lab company should provide a short summary regarding whether or not the compound is in fact the correct one and numbers for the estimated purity. Also provided are the mass spectra, which can be compared with the standard spectra for the compound, which can be found at DrugBank or other sources online.

Ingestion Logistics

MitoQ comes prepackaged in a convenient pill form, so there is no need to do any additional work here. Just take the pills in the appropriate amount. If ordered from a source other than MitoQ Limited, it may arrive dissolved in an ethanol solution, or as a solid. Similarly, an order of SkQ1 will arrive as a tiny amount of powder that needs to be dissolved in solution in order to be ingested. Neither MitoQ nor SkQ1 is soluable in water. In dry form they should be dissolved in a minimal amount of ethanol or dimethyl sulfoxide (DMSO) - very little is needed, and can be applied gradually with a dropper. Then pour the resulting solution into a glass of water and drink it. This will roughly replicate the delivery mode used in many of the animal studies.

Establishing Tests and Measures

The objective here is a set of tests that (a) match up to the expected outcome based on human trials of mitochondrially targeted antioxidants, and (b) that anyone can run without the need to involve a physician, as that always adds significant time and expense. These tests are focused on the cardiovascular system, particularly measures influenced by vascular stiffness, and some consideration given to parameters relevant to oxidative stress and the development of atherosclerosis.

The cardiovascular health measures in that list are those that are impacted by changes in the elasticity or functional capacity of blood vessels, such as would be expected to occur to some degree in a treatment that compensated in some way for the effects of aging on the smooth muscule cells in blood vessel walls - as is thought to be the case for mitochondrially targeted antioxidants. Positive change of the average values in most of these metrics are achievable with significant time and effort spent in physical training, so movement in the numbers in a short period of time as the result of a treatment should be an interesting data point.


There exist online services such as WellnessFX where one can order up a blood test and then head off the next day to have it carried out by one of the widely available clinical service companies. Of the set of test packages offered by WellnessFX, the Baseline is probably all that is needed for present purposes. But shop around; this isn't the only provider.

Oxidized LDL Cholesterol

The more mainstream blood test services such as WellnessFX don't offer as wide a range of testing as some of the specialists. For example, the Life Extension Foundation maintains a blood test service that includes a test for oxidized LDL cholesterol. Again, shop around. There are others.

Resting Heart Rate and Blood Pressure

A simple but reliable tool such as the Omron 10 is all you need to measure heart rate and blood pressure. It is worth noting here a couple of general principles for cardiovascular measures. Firstly, the further away from the center of the body that the measurement is taken, the less reliable it is - the more influenced by any number of circumstances, such as position, mood, stress, time of day, and so forth. Fingertip devices are convenient, but nowhere near as useful as something like the Omron 10 that uses pressure on the upper arm. Secondly, all of the above-mentioned line items also influence every cardiovascular measure, so when you are creating a baseline or measuring changes against that baseline, carry out each measure in the same position, at the same time of day, and make multiple measurements over a week to gain a more accurate view of the state of your physiology. The Omron 10 is solid: it just works, and seems quite reliable.

Heart Rate Variability

Surprisingly few of the numerous consumer tools for measuring heart rate variability actually deliver the underlying values used in research papers rather than some form of aggregate rating derived by the vendor; the former is required for any serious testing, and the latter is useless. Caveat emptor, and read the reviews carefully. As an alternative to consumer products, some of the regulated medical devices are quite easy to manage, but good luck in navigating the system to obtain one. The easiest way is to buy second hand medical devices via one of the major marketplaces open to resellers, but that requires a fair-sized investment in time and effort - which comes back to the rule about keeping things simple at the outset.

After some reading around the subject, I settled on the combination of the Polar H10 device coupled with the SelfLoops HRV Android application. I also gave the EliteHRV application a try. Despite the many recommendations for Polar equipment, I could not convince either setup to produce sensible numbers for heart rate variability data: all I obtained during increasingly careful and controlled testing was a very noisy set of clearly unrealistic results, nowhere near the values reported in papers on the subject. However, plenty of people in the quantified self community claim that these systems work reasonably well, so perhaps others will have better luck than I. Take my experience as a caution, and compare data against that reported in the literature before investing a lot of time in measurement.

Pulse Wave Velocity

For pulse wave velocity, choice in consumer tools is considerably more limited. Again, carefully note whether or not a device and matching application will deliver the actual underlying data used in research papers rather than a made-up vendor aggregate rating. I was reduced to trying a fingertip device, the iHeart, picked as being more reliable and easier to use than the line of scales that measure pulse wave velocity. Numerous sources suggest that decently reliable pulse wave velocity data from non-invasive devices is only going to be obtained by measures at the aorta and other core locations, or when using more complicated regulated medical devices that use cuffs and sensors at several places on the body.

Still, less reliable data can be smoothed out to some degree by taking the average of measures over time, and being consistent about position, finger used for a fingertip device, time of day, and so forth when the measurement is taken. It is fairly easy to demonstrate the degree to which these items can vary the output - just use the fingertip device on different fingers in succession and observe the result. All of this is a trade-off. A good approach is to take two measures at one time, using the same finger of left and right hand, as a way to demonstrate consistency. While testing an iHeart device in this way, I did indeed manage to obtain consistent and sensible data, though there is a large variation from day to day even when striving to keep as many of the variables as consistent as possible. That large variation means that only sizable effects could be detected.

DNA Methylation

DNA methylation tests can be ordered from either Osiris Green or Epimorphy / Zymo Research - note that it takes a fair few weeks for delivery in the latter case. From talking to people at the two companis, the normal level of variability for repeat tests from the same sample is something like 1.7 years for the Zymo Research test and 4.8 years for the Osiris Green tests. The level of day to day or intraday variation between different samples from the same individual remains more of a question mark at this point in time, though I am told they are very consistent over measures separated by months. Nonetheless, as for the cardiovascular measures, it is wise to try to make everything as similar as possible when taking the test before and after a treatment: time of day, recency of eating or exercise, recent diet, and so forth.

An Example Set of Daily Measures

An example of one approach to the daily cardiovascular measures is as follows, adding extra measures as a way to demonstrate the level of consistency in the tools:

  • Put on the Polar H10; this is involved enough to increase heart rate a little for a short period of time, so get it out of the way first.
  • Sit down in a comfortable position and relax for a few minutes.
  • Measure blood pressure and pulse on the left arm using the Omron 10.
  • Measure blood pressure and pulse on the right arm using the Omron 10.
  • Measure pulse wave velocity on the left index fingertip over a 30 second period using the iHeart system.
  • Measure pulse wave velocity on the right index fingertip over a 30 second period using the iHeart system.
  • Measure heart rate variability for a ten minute period using the Polar 10 and Selfloops.

Consistency is Very Important

Over the course of an experiment, from first measurement to last measurement, it is important to maintain a consistent weight, diet, and level of exercise. Sizable changes in lifestyle can produce results that may well prevent the detection of any outcome using the simple tests outlined here. Further, when taking any measurement, be consistent in time of day, distance in time from last exercise or meal, and position of the body. Experimentation with measurement devices will quickly demonstrate just how great an impact these line items can have.

Guesstimated Costs

The costs given here are rounded up for the sake of convenience, and in some cases are blurred median values standing in for the range of observed prices in the wild.

  • Business mailbox, such as from UPS: $250 / year
  • Baseline tests from WellnessFX: $220 / test
  • Oxidized LDL test from LEF: $170 / test
  • MyDNAage kits: $310 / kit
  • Osiris Green sample kits: $70 / kit
  • Omron 10 blood pressure monitor: $80
  • Polar H10 heart monitor: $100
  • iHeart monitor: $210
  • American Weigh Gemini-20 microscale: $90
  • Miscellenous equipment: spatulas, labels, vials, pill capsules, etc: $60
  • SkQ1 via Alibaba: $200
  • A bottle of dimethyl sulfoxide (DMSO): $20
  • MitoQ capsules from MitoQ Limited: $190
  • Shipping and LC-MS analysis of samples: $120 / sample

Schedule for the Self-Experiment

One might expect the process of discovery, reading around the topic, ordering materials, and validating the pharmaceuticals to take a couple of months. Once all of the decisions are made and the materials are in hand, pick a start date. The schedule for the self-experiment is as follows:

  • Day 1-10: Once or twice a day, take measures for blood pressure, pulse wave velocity, and heart rate variability.
  • Day 10: Bloodwork and DNA methylation test.
  • Day 11: Start on the six week program of daily doses.
  • Day 53-62: Repeat the blood pressure, pulse wave velocity, and heart rate variability measures.
  • Day 62: Repeat the bloodwork and DNA methylation test.

Where to Publish?

If you run a self-experiment and keep the results to yourself, then you helped only yourself. The true benefit of rational, considered self-experimentation only begins to emerge when many members of community share their data, to an extent that can help to inform formal trials and direction of research and development. There are numerous communities of people whose members self-experiment with various compounds and interventions, with varying degrees of rigor. One can be found at the LongeCity forums, for example, and that is a fair place to post the details and results of a personal trial. Equally if you run your own website or blog, why not there?

When publishing, include all of the measured data, the compounds and doses taken, duration of treatment, and age, weight, and gender. Fuzzing age to a less distinct five year range (e.g. late 40s, early 50s) is fine. If you wish to publish anonymously, it should be fairly safe to do so, as none of that data can be traced back to you without access to the bloodwork provider. None of the usual suspects will be interested in going that far. Negative results are just as important as positive results. For example, given the measures proposed in this post it is entirely plausible that positive changes in a basically healthy late 40s or early 50s individual will be too small to identify - they will be within the same range as random noise and measurement error. Data that confirms this expectation is still important and useful for the community, as it will help to steer future, better efforts.

Reduced Expression of Antimicrobial Peptide Genes Partially Determines the Temperature-Lifespan Relationship in Flies

Short-lived species have a much greater plasticity of life span in response to environmental circumstances than is the case for long-lived species such as our own. Among the most important factors are calorie intake and temperature of the surrounding environment. Both produce sweeping changes in metabolism, and are thus challenging to investigate. Nonetheless, researchers here appear to have identified one of the drivers of the relationship between temperature and lifespan in flies, centered around a portion of the innate immune system that may have multiple roles in the regulation of metabolism.

Fruit flies, which are ectothermic animals, can live more than twice as long at 18°C than at 25°C. Even though it has been thought that this enhanced longevity at a lower temperature (18°C) is caused by a change of metabolic rate, the mechanisms that regulate longevity by ambient temperature are poorly understood. Previously, we found that development at 18°C significantly enhances stress resistance of adult flies with more accumulation of nutrients (especially fat) in the body than development at 25°C. This enhanced resistance to stress was similarly observed in both sexes and sustained up to 30 days after hatching of the adult flies indicating that development at a lower temperature, 18°C, significantly enhances the mechanism(s) of stress resistance.

Higher stress resistance and/or fat accumulation are frequently found in long-lived flies such as mutants of the IGF (insulin/insulin-like growth factor) signaling pathway. From tests of representative stress-related genes, we showed that the development at a lower temperature (18°C) downregulates antimicrobial peptide genes, AttA and DptB, of the Immune deficiency (Imd) pathway. The Imd pathway is known to regulate innate immune responses in Drosophila, and the Imd protein activates two downstream branches which are subsequently responsible for the upregulation of stress tolerance and antimicrobial peptide genes.

The roles of the Imd pathway have been well studied in a humoral response against intruders, which is characterized by the secretion of antimicrobial peptides (AMPs) into the hemolymph. However, whether the Imd pathway is involved in a longevity mechanism has not been reported. Using hypomorphic imd and AttC mutant flies, here, we show that the mild downregulation of the Imd pathway has a beneficial effect for stress resistance with higher fat content in the body even when developed at 25°C. The Imd pathway functions for the immune response in the fat body which is involved in the metabolism and storage of fat in adult flies. Surprisingly, our data show that the fat-body-specific downregulation of Imd AMP genes significantly enhances heat resistance and extends lifespan.

In summary, our data indicate that mild downregulation of the Imd pathway increases stress resistance, lifespan, and fat content in adult flies, which mimics the enhanced stress resistance caused by a lower developmental temperature.


An Interview on Mitochondrial Damage and Dysfunction in Aging

In this interesting interview, the topic is mitochondria and their role in aging. Mitochondria are the power plants of the cell, descendants of ancient symbiotic bacteria that still contain a small genome left over from that origin. Small it might be, but it is significant: stochastic damage to mitochondrial DNA (mtDNA) is one of the root causes of aging. Through a complex chain of events, this results a small but significant fraction of cells overtaken by mutant mitochondria and made to export harmful levels of oxidative molecules into surrounding tissues. This, to pick one example, produces oxidized lipids in the bloodstream that irritate blood vessel walls to start the inflammatory cascade that results in atherosclerosis. Quite aside from this process, however, mitochondria also undergo a general decline with advancing age, changing in many ways, and failing to keep up with their primary task of energy store production. This may be a reaction to other forms of damage in the tissue environment, and is particularly problematic in energy-hungry tissues like the brain and muscles.

Mitochondria, first and foremost, are these double membrane bound organelles that are in, essentially, all cells in your body. What makes them particularly interesting is that there are hundreds to thousands of them in each cell. The mitochondria produce the bulk of the ATP that you use every day, ATP is the energy currency of the cell. The other critical thing about mitochondria, is they have their own genome. You have your nuclear genome, where you got one copy from your mother, one from your father, but with respect to mitochondrial genomes, you have hundreds to thousands of them. Those are distributed among these organelles floating in the cytoplasm.

A final feature of mitochondria that turns out to be very important, they're not just static structures that sit in the cytoplasm like parked cars. They actually fuse with each other and then share contents and then they can also break apart, undergo fission. The sharing of components allows cells to, often times, maximize the amount of ATP that they want to produce. This turns out to have important consequences because it also does something else that's not so good, that defeats the ability to identify mitochondria containing mitochondrial DNA that is in some way mutant.

The way to think about this is the idea of quality control. The question is, mitochondria are always being generated, they have to work very hard, they create a lot of free radicals, a lot of damaging small molecules, and eventually they get turned over. So, even in non-dividing cells like muscle and neurons in your brain, the mitochondria are always being generated and then always being destroyed. That's important, because if you didn't get rid of these damaged mitochondria they would accumulate, and your cells wouldn't survive that, because they would lose the ability to generate energy.

The key issue with respect to quality control and mtDNA, and the fact that there are many mitochondria, or many mitochondrial genomes per cell, is that quality control may take a backseat, often times, to meeting more immediate cellular needs, like maximizing ATP production. Which is fine when you're young, but as you get older, and as that damage starts to accumulate, then you would really like it if quality control could kick in and do a bit of housecleaning.

We should think of mitochondrial DNA in a way, perhaps, still having its own selfish interests, left over from symbiosis. Because there is constant turnover, the mitochondria in you today aren't necessarily the ones that make you the most fit as an individual. They're the ones that survive this intracellular competition with other mitochondria and other mitochondrial genomes, the ones that have found a way to increase in frequency. The reason this relates to aging is that it turns out, as we age, we accumulate mutant mitochondrial DNA, such that, at some point, cells have so much mutant mtDNA that they either die or become otherwise dysfunctional. That leads to loss of function in critical tissues like heart, muscle, and the nervous system.

A very interesting question that we don't know the answer to is to figure out how it is that mutant genomes, in particular, deleterious genomes, seem to preferentially get amplified. There seems to be something a little bit haywire in cells, often, such that the quality control machinery, while it may exist, it doesn't get rid of the bad mitochondria with their mutant genomes. Those genomes have instead, found some way to increase in frequency and that then leads to a problem with aging.