Clearing Microglia Without Clearing Amyloid Produces Benefits in a Mouse Model of Alzheimer's Disease

Researchers have reduced inflammation and cell death in a mouse model of Alzheimer's disease by reducing the numbers of microglia present in brain tissue, an approach that doesn't reduce amyloid-β levels associated with the progression of Alzheimer's disease even though it results in functional benefits. Microglia are a class of immune cell specific to the brain, where portions of the immune system have more roles and more complicated roles than is the case elsewhere in the body. Types of immune cell only found in the brain are responsible for supporting neurons in many ways, not just by attacking pathogens. Dysfunction in microglia has long been implicated in the chronic inflammation that accompanies many neurodegenerative conditions, and microglia are a target for numerous lines of research related to potential Alzheimer's therapies, which in some cases include increasing microglial activity or otherwise altering their behavior rather than the approach of removal tried here.

Animal models are never the same as the human disease they are trying to mimic, and that can mean garbage in, garbage out. Judging relevance of results must always be on a case by case basis, and while considering all of the fine details, because just as it is possible to learn a great deal from a good animal model, it is also possible to create states and scenarios in that same animal model that have no real relevance to human biochemistry. For example, researchers have in the past created scenarios in which mice are heavily loaded with amyloid-β and yet show few or no signs of neurodegeneration, and it has never been entirely clear as to the degree to which that helps in understanding Alzheimer's disease in humans. This microglia study might help shed some further light on those results, at least in mouse models, given the inflammation angle. It is generally accepted that inflammation is important in the progression of Alzheimer's disease, and there are certainly other studies in mice models in which reductions in inflammation have been shown to reduce Alzheimer's-like symptoms.

On the whole, this study does well as supporting evidence for those who are trying to build treatments for neurodegenerative conditions based on targeting microglia. As is the case for a lot of the work on Alzheimer's in animal models, it raises at least as many questions as it answers, however.

Blocking inflammation prevents cell death, improves memory in Alzheimer's disease

Researchers found that flushing away the abundant inflammatory cells produced in reaction to beta-amyloid plaques restored memory function in test mice. Their study showed that these cells, called microglia, contribute to the neuronal and memory deficits seen in this neurodegenerative disease. "Our findings demonstrate the critical role that inflammation plays in Alzheimer's-related memory and cognitive losses. While we were successful in removing the elevated microglia resulting from beta-amyloid, further research is required to better understand the link among beta-amyloid, inflammation and neurodegeneration in Alzheimer's."

The neurobiologists treated Alzheimer's disease model mice with a small-molecule inhibitor compound called pexidartinib, or PLX3397, which is currently being used in several cancer studies. The inhibitor works by selectively blocking signaling of microglial surface receptors, known as colony-stimulating factor 1 receptors, which are necessary for microglial survival and proliferation in response to various stimuli, including beta-amyloid. This led to a dramatic reduction of these inflammatory cells, allowing for analysis of their role in Alzheimer's. The researchers noted a lack of neuron death and improved memory and cognition in the pexidartinib-treated mice, along with renewed growth of dendritic spines that enable brain neurons to communicate. Although the compound swept away microglia, the beta-amyloid remained, raising new questions about the part these plaques play in Alzheimer's neurodegenerative process.

Eliminating microglia in Alzheimer's mice prevents neuronal loss without modulating amyloid-β pathology

In addition to amyloid-β plaque and tau neurofibrillary tangle deposition, neuroinflammation is considered a key feature of Alzheimer's disease pathology. Inflammation in Alzheimer's disease is characterized by the presence of reactive astrocytes and activated microglia surrounding amyloid plaques, implicating their role in disease pathogenesis. Microglia in the healthy adult mouse depend on colony-stimulating factor 1 receptor (CSF1R) signalling for survival, and pharmacological inhibition of this receptor results in rapid elimination of nearly all of the microglia in the central nervous system.

In this study, we set out to determine if chronically activated microglia in the Alzheimer's disease brain are also dependent on CSF1R signalling, and if so, how these cells contribute to disease pathogenesis. Ten-month-old 5xfAD mice were treated with a selective CSF1R inhibitor for 1 month, resulting in the elimination of ∼80% of microglia. Chronic microglial elimination does not alter amyloid-β levels or plaque load; however, it does rescue dendritic spine loss and prevent neuronal loss in 5xfAD mice, as well as reduce overall neuroinflammation. Importantly, behavioural testing revealed improvements in contextual memory. Collectively, these results demonstrate that microglia contribute to neuronal loss, as well as memory impairments in 5xfAD mice, but do not mediate or protect from amyloid pathology.

Engineered Calcium Receptors in the Heart Improve Function

Researchers here demonstrate that using gene therapy to introduce a modified calcium receptor into the heart can improve the calcium signaling that drives the heartbeat, and that the effects are measurable even for a small uptake of the new receptor in heart cells. In the context of heart disease and degenerative aging of the heart, this approach could partially compensate for progressive failure of function in the organ, though it doesn't fix any of the underlying cell and tissue damage, or the prior remodeling of the heart caused by arterial stiffening and consequent hypertension.

Researchers have engineered new calcium receptors for the heart to tune the strength of the heartbeat in an animal model. The team developed a protein engineering approach by tailoring the heart's ability to respond to calcium, which is the signal for contraction. Using a modified version of troponin C (TnC L48Q), their study showed it can enhance or therapeutically preserve heart function and cardiovascular performance in mice without harmful effects commonly seen with other agents that increase heart muscle contraction.

Most heart muscle diseases involve problems with contraction. Many strategies increase the calcium signal to improve heart contraction. However, they do so at the expense of other functions. This can cause negative side effects, such as arrhythmias and cell death, and ultimately increase mortality. The team evaluated TnC L48Q in a common heart pathology - myocardial infarction, or a heart attack. Compared to the infarcted control group, TnC L48Q mice had better heart function and cardiovascular performance. There were also no signs of congestive heart failure or increased mortality, both of which were observed in the control group. When assessing the long-term effects and therapeutic potential of TnC L48Q, the researchers observed steady and significant improvement in heart function, cardiovascular performance, and significantly less detrimental remodeling compared to the control group. This resulted in better survival.

"It's long been presumed that altering the receptor would be ineffective, that it was better to change the calcium signal. We're seeing strong evidence that's not the case. Changing the calcium receptor does have a significant and safer impact." The scientists report these results were achieved by replacing only a modest amount of the original TnC receptor through gene therapy. This makes it more likely that this strategy will be a viable and personalized treatment option in the future. The researchers believe these findings could open the door for new treatments against cardiac diseases. In previous in vitro work, the team has customized several TnC receptors designed to combat various cardiac disorders. The team is also working on engineering other calcium receptors for a variety of diseases, such as high blood pressure and heart arrhythmias.


New Problems in Nematode Life Span Studies

Researchers have uncovered a new way in which many past studies of extended life span in nematode worms have been distorted by a part of the experimental process. This isn't the first time this has happened in recent years. The metabolic processes and life spans of short-lived species are very plastic in response to all sorts of circumstances, and thus smaller effects are easier to produce, intentionally and otherwise. As a general rule these effects are irrelevant to longer-lived species, where life span is much less plastic. Even large extension of life in short-lived species via methods of metabolic alteration that have also been tried in humans, such as calorie restriction or growth hormone receptor loss of function, have no such matching effect in humans.

In matters of the fundamental molecular biology of aging, we mammals are not so different from tiny C. elegans worms. Some of the biggest differences only serve to make them convenient research models. But one distinction - their ability to asexually reproduce exact copies of themselves - may have led to many research discrepancies. The reason, according to a new study, is that the drug scientists use prevent such confusing reproduction turns out to help aging worms rebound from stress, thereby significantly lengthening their lifespan in some cases. In the study researchers identify the human chemotherapy drug FUdR as the culprit. Their detailed experiments show that the drug goes well beyond squelching worm reproduction. It also triggers stress response and turns on DNA repair pathways (that are also found in mammals) that allow the worms to better endure adverse conditions such as saltiness, heat, or low oxygen.

"We can explain a lot of the disagreement in the C. elegans aging field by realizing that FuDR can dramatically change the answer. There were very different effects in published papers that had different doses of FUdR in them. Sometimes it's a very profound disagreement." Moreover, some other studies may involve FUdR-related discrepancies but insufficient documentation of the methods prevented researchers from being sure.

In the absence of any stress, FUdR makes no difference to lifespan in normal worms, they confirmed. But when worms were exposed to a modest concentration of salt, animals who were not exposed to FUdR had only half the lifespan of those who were exposed to the drug. Meanwhile, adding even more FUdR caused even longer lifespan under salt stress. A tenfold increase in FUdR concentration extended lifespan by a factor of three. Other experiments suggested that FUdR causes better stress resistance in hot or low-oxygen conditions. Further research revealed details of how FUdR protects the worms from stress. They found evidence that the drug turns on the gene that produces the protein FOXO, a master regulator of stress resistance in many organisms that is often central in longevity studies. They also found that exposure to FUdR forced DNA mutations that then activated a DNA-repair process. That process, once activated, also fixes a lot of DNA damage caused by environmental stresses, including dreaded double-strand breaks, a clean severing of the DNA molecule.

Link: Project: Help to Crowdfund the Sinclair Lab NMN Calorie Restriction Mimetic Lifespan Study in Mice

The crew have launched their latest longevity science crowdfunding project in partnership with the Sinclair lab at Harvard: the goal is to raise funds for a novel calorie restriction mimetic mouse life span study based on research published last year. You might recall that David Sinclair was the researcher behind Sirtris, one of the more hyped initiatives in sirtuin research, though far from the only one. Over the past twenty years a lot of work has gone into trying to understand the activities of proteins and pathways thought to be important in the extended longevity produced by calorie restriction in short-lived species, sirtuins among their number, and there was considerable enthusiasm for drug development along these lines a decade ago. A few companies were founded, such as Sirtris, but while some people made a bunch of money, nothing came out of this save for a greater appreciation of the complexities of cellular metabolism and a mountain of new data.

Research on sirtuins didn't halt following the realization that this wasn't a fast path to modestly slowing the aging process. It continues, along with a great many other, similar investigations into the detailed operation of mammalian biochemistry, and how it changes in response to circumstances. In fact much of aging research and longevity science even now is arguably just a thin excuse to bring funds into the grand endeavor of mapping cellular metabolism, in much the same way that Alzheimer's research is used as the rallying banner for fundamental work on understanding the biochemistry of the brain. Decades of work remain to be accomplished in the project of mapping metabolism in the context of aging, even given the advanced tools of modern biotechnology. Actions speak louder than words, and most scientists in the field are doing a lot more mapping than work on potential treatments for aging.

So what are the researchers at the Sinclair lab up to these days? You might recall that they are investigating possible drug candidates to alter the behavior of mitochondria for the better in aged tissues, which is another line of research fairly closely connected to calorie restriction. This particular approach involves manipulating nicotinamide adenine dinucleotide (NAD) levels using compounds such as nicotinamide mononucleotide (NMN) or precursors. NAD levels decline with aging, decline more slowly in calorie restricted individuals, and restoring NAD levels artificially has been shown to produce some benefits in old mice. However there is yet a lot of uncertainty in this; it is a good thing at this point to remember the data on and view of sirtuins and their relevance to aging, and how that changed over time. For my money the research on this to date at the Sinclair lab is much more interesting for the connections it exposes between mitochondria, nutrient sensing, and regulation of cellular maintenance, some of the foundation stones for the operation of hormesis, than as the basis for therapies.

Can NMN Reverse the Effects of Aging in Mice?

One of the best studied anti-aging treatments is a diet reduced in calories, yet high enough in nutrients to avoid malnutrition. Known as calorie restriction (CR), this dietary regimen provides irrefutable evidence of the importance of metabolism in the aging process. While CR has been studied extensively and even tested in human trials, long term adherence to a CR dietary regimen is extremely difficult for most individuals to maintain. One method to achieve the benefits of CR for everyone would be to administer compounds which act as a "CR mimetic." Such compounds are capable of stimulating the cellular signaling cascades that are normally induced during CR. Over the past 20 years, we have made great strides in understanding the key cellular components involved in mediating many of the metabolic changes that contribute to the aging process.

A major metabolic signaling molecule that we and others have shown to exhibit significant declines with increasing age is NAD+. Importantly, CR reverses the age-related decline of bioavailable NAD+. This key metabolite plays a crucial role in regulating the activity of many important signaling molecules involved in age-related diseases. However, feeding or administering NAD+ directly to organisms is not a practical option. The NAD+ molecule cannot readily cross cell membranes and therefore would be unavailable to positively affect metabolism. Instead, precursor molecules to NAD+ must be used to increase bioavailable levels of NAD+.

One such metabolic precursor of NAD+, niacin, is currently used as a medical therapeutic in humans to regulate blood lipid profiles and ward off cardiovascular disease. Niacin, however, has unwanted side-effects and is separated by too many metabolic steps upstream of the final production of cellular NAD+ to substantially impact the magnitude of NAD+ bioavailability. Recently, we have shown that by administering the NAD+ precursor NMN (Nicotinamide Mononucleotide) in normal drinking water, bioavailable NAD+ levels were restored to those normally associated with younger healthy animals. By administering NMN to mice for just one week, our lab demonstrated a robust correction in age-associated metabolic dysfunction and restored muscle function in old mice to levels seen in younger control mice.

In our project, we will test the hypothesis that by restoring bioavailable NAD+, we can reverse the aging process. Starting with mice that are one year old (roughly equivalent to a 30 year old human), longer-term NMN treatments will be applied in order to restore levels of cellular NAD+ to those found in youthful mice. Along with a large cohort of normal mice, a novel genetically engineered mouse, termed the ICE mouse (Induced Change in Epigenetics) will be used during the trial. These ICE mice manifest an accelerated aging phenotype and as a result are short lived. By using ICE mice in our trial, in addition to normal control mice, we will be able to more rapidly test the effectiveness of potential anti-aging treatments, such as NMN, thus obtaining faster experimental results.

Your donations will not only allow us to purchase the materials necessary to perform this experiment, but also open the doors to working together with you in the future eventually leading to human clinical trials aimed at showing, for the first time, that we can actually slow down human aging.

As I'm sure you're all aware by now, I'm really not in favor of traditional drug development with the goal of modestly slowing the aging process. The prime example of this is any attempt to recapture some fraction of the effects of calorie restriction by tinkering with the operation of metabolism. One of the good things to come out of years of sirtuin research is that it now serves as a calibration point to demonstrate (a) just how expensive it is to try to manipulate the operation of metabolism with drugs, even when seeking to recreate a well-studied and easily reproduced natural metabolic state like the calorie restriction response, and (b) just how unlikely it is for this sort of approach to produce useful therapies, even given large investments of time and money. So I'd say that helping to fund this proposed life span study in mice using nicotinamide mononucleotide as a calorie restriction mimetic should be approached with the view that you are assisting fundamental research with the aim of understanding more of the relationships between mitochondria, calorie restriction, and aging, not that you are assisting an approach likely to lead to useful therapies in humans. Clearly life span studies like this are useful fundamental life science research, of the sort undertaken by the Interventions Testing Program and the NIA, who never have enough funding to do as much as they'd like to do, but they are not in the same class of expected value as SENS rejuvenation research projects.

Reopening Development of β-secretase Inhibitors as a Therapy for Alzheimer's Disease

One approach to the treatment of Alzheimer's disease is to interfere in the production of β-amyloid rather than trying to clear it after it has been produced. Insofar as Alzheimer's is a disease of amyloid accumulation, the evidence suggests it results from a gradual failure of clearance and filtration mechanisms operating on cerebrospinal fluid, and amyloid levels are fairly dynamic on a short time frame. This makes blocking production more viable here than in age-related conditions where the causative metabolic waste accumulates and clears only slowly. One possible way to block production is to interfere with the proteins that produce β-amyloid from amyloid precursor protein, but as this article points out, that has proven to be challenging:

Protein deposits in the brain are hallmarks of Alzheimer's disease and partly responsible for the chronically progressive necrosis of the brain cells. Nowadays, these plaques can be detected at very early stages, long before the first symptoms of dementia appear. The protein clumps mainly consist of the β amyloid peptide (Aβ), a protein fragment that forms when two enzymes, β and γ secretase, cleave the amyloid precursor protein (APP) into three parts, including Aβ, which is toxic. If β or γ secretase is blocked, this also inhibits the production of any more harmful β amyloid peptide. Consequently, for many years biomedical research has concentrated on these two enzymes as therapeutic points of attack. To date, however, the results of clinical studies using substances that block γ secretase have been sobering. The problem is that the enzyme is also involved in other key cell processes. Inhibiting the enzymes in patients therefore triggered severe side effects, such as gastrointestinal hemorrhaging or skin cancer.

For a number of years researchers have also been focusing their efforts on β secretase. A large number of substances have been developed, including some highly promising ones that reduced the amount of Aβ in mouse models effectively. Nevertheless this presents the same challenge: "The current β secretase inhibitors don't just block the enzyme function that drives the course of Alzheimer's, but also physiologically important cell processes. Therefore, the substances currently being tested in clinical studies may also trigger nasty side effects - and thus fail." To address this, researchers studied how β secretase might be inhibited selectively - in other words, the harmful property blocked without affecting any useful functions. In a series of experiments, the scientists were able to demonstrate that the Alzheimer's protein APP is cleft by β secretase in endosomes, special areas of the cells that are separated by membrane envelopes, while the other vital proteins are processed in other areas of the cell. The researchers exploited this spatial separation of the protein processing within the cell.

"We managed to develop a substance that only inhibits β secretase in the endosomes where the β amyloid peptide forms. The specific efficacy of our inhibitor opens up a promising way to treat Alzheimer's effectively in future, without causing the patients any serious side effects." The researchers' next goal is to hone their drug candidate so that it can initially be tested in mice and ultimately in clinical studies on Alzheimer's patients.


Even Small Gains in Healthy Longevity Bring Huge Economic Benefits

Even small changes in the trajectory of aging bring enormous economic gains, and here I'll point out an interview with one of the few economists to have modeled these gains, albeit for small increases in healthy life span after the Longevity Dividend view of slightly slowing the progression of aging via calorie restriction mimetic drugs and the like. Most expenditure on healthcare occurs due to aging, and increases greatly in the final stages of life. Care of those disabled by aging and the provision of largely palliative therapies for late stage age-related disease are both expensive undertakings, and because existing treatments don't target the causes of aging and age-related disease they are also unreliable and of only marginal benefit. This situation will change radically in the years ahead as the first therapies following the SENS vision for rejuvenation biotechnology arrive in the clinic, capable of repairing the cell and tissue damage that causes aging, with senescent cell clearance and transthyretin amyloid clearance first out of the gate. The deployment of the full spectrum of SENS treatments will do far more than add just a couple of years to life.

ResearchGate: What are the economic benefits of delayed aging?

Dana Goldman: We need to think about benefits more broadly than just traditional measures like Gross Domestic Product (GDP). Now that people are living longer, we need to make decisions about a whole host of treatments for diseases like cancer and Alzheimer's that are much more prevalent post-retirement. Thus, economists have developed ways to think about - and measure - the benefits of a healthy, productive life using the concept of a quality-adjusted life year. Thus, the 'economic' benefits come from better functioning, improved cognition, and a life free of comorbidities as much as possible. The key benefit of delayed aging is not just to extend life, but to also reduce the amount of time we spend with disability and disease - all of which can be measured and valued.

RG: How do the projected benefits compare with the costs?

DG: Once we do a good job valuing the health gains - both in terms of life expectancy and quality of life - it is clear that the benefits likely outweigh the costs by a factor of ten or more. This does not mean that delayed aging will pay for itself in reduced health care spending - quite the contrary. However, it is a very different question to ask if the medical spending is less or more than to ask if the benefits outweigh the costs. That is because the benefits include all the value we place on healthier, longer life. For example, we find that if the promise of delayed aging is fully realized - based on the best animal models - we could increase life expectancy by an additional 2.2 years, most of which would be spent in good health. The economic value of would be about $7.1 trillion over fifty years - with little additional government costs if we index Medicare and Social Security to the life expectancy increases.

RG: Research has shown that delayed aging simultaneously lowers the risk of all fatal and disabling diseases. What changes to healthcare systems and related costs do you foresee?

DG: This makes delayed aging a lot like other important interventions we know about, like reduced smoking, more physical activity, or a better diet. All of those 'treatments' have benefits for a constellation of illnesses. The big change we need is to make sure the health care system is rewarded for keeping people free of disease, rather than getting paid only when people get sick.


Using Epigenetic Measures of Age to Determine that Cellular Aging is Distinct From Cellular Senescence

One of the research groups involved in developing biomarkers of aging based on characteristic epigenetic changes published a most interesting paper earlier this month, linked below, in which they use their tools to investigate cellular senescence and cell aging. Biomarkers to measure biological age, the degree to which an individual is damaged and their biology has become dysfunctional in response to that damage, are an important line of development. An effective biomarker might be used to quickly assess the overall benefits of a potential rejuvenation therapy in mammals. As an alternative to running full life span studies this would dramatically reduce the time and cost required for such research. Cheaper research and faster results are certainly good for the pace of progress where they can be achieved.

Individual cells age, accumulating metabolic waste and unrepaired damage in the case of long-lived cells, or marching towards the Hayflick limit placed on the number of divisions permitted them in the case of short-lived somatic cells, but the relationship between cellular aging and tissue aging is not a straightforward one. A living being is a a dynamic system in which the majority of cells that make up its tissues are at some point replaced, on a schedule of days or months in most cases. Only in the central nervous system and a few other places do we find individual cells lasting a very long time, even the whole lifetime, and in which the steady accumulation of damage and waste are more important factors. In most tissues the importance is the pace of turnover, the number of lingering senescent cells that behave badly and refuse to die, the level of waste in the environment outside cells, and the quality of the stem cells that are responsible for producing a supply of new somatic cells to keep tissue functional.

Cells become senescent, removing themselves from the cycle of division and replication in response to a range of circumstances: damage, a toxic local environment, short telomeres as a result of reaching the Hayflick limit, and so forth. This probably serves to reduce cancer risk, at least initially, but senescent cells generate harmful signals that degrade surrounding tissues and produce localized inflammation. As their numbers grow, this damaging behavior contributes meaningfully to degenerative aging. As illustrated by recent research linking mitochondrial dsyfunction and cellular senescence, cells are very complicated machines: senescence isn't a single uniform state, not all senescent states are similar, and nor is it the case that all of the states that can be created in the laboratory are known to occur to a significant degree in living tissues. So this is an interesting area of cellular biochemistry to explore, even as clinical development is moving ahead on the blunt and direct approach of clearing senescent cells from the body so as to remove their detrimental effects. This is absolutely the way things should be: taking the fast road to therapies that will effectively treat the causes of aging even in the absence of detailed understanding, and those researchers who can raise funds for more leisurely investigation and mapping can continue their work in the meanwhile. If only this were the case in other fields relevant to aging, but for the most part only the leisurely investigation is taking place there.

Epigenetic clock analyses of cellular senescence and ageing

One model of ageing posits that the failure of tissues to function properly is due to the depletion of stem cells. Stem cells, which are the reservoir cells of tissues, may have finite capacities of proliferation such as being limited by the lengths of their telomeres. Their eventual depletion leads to the deficit of properly functioning cells, causing phenotypic changes that constitute ageing. While this model is plausible and supported by strong circumstantial evidence, it is presently difficult to prove or refute directly, not least because the identification of specific tissue stem cells is difficult. Similarly, the association between telomere length and ageing, although widely reported, is not without inconsistencies.

There is however, another model of ageing which is based on the observation that the number of senescent cells in the body increases in function of organism age. While this could be interpreted to mean that senescent cells cause ageing, it could also equally mean that senescent cells are a consequence of ageing. In this regard, it is noteworthy that there is increasing evidence to demonstrate that senescent cells are not benign. Instead they secrete bio-chemicals that are detrimental to normal functioning of neighbouring cells. The senescence-associated secretory phenotype (SASP) proteins include cytokine, chemokines and proteases and their paracrine activities are very diverse and include oncogenic characteristics that stimulate cellular proliferation and epithelial-mesenchymal transition. Importantly, SASP proteins also promote chronic inflammation, which is the origin of almost all age-related pathologies. As such, SASP proteins, through their different effects on normal and cancer cells, induce deterioration of the tissue. Recently, it was demonstrated that removal of senescent cells in mice delays ageing-associated disorders, providing very strong support for the notion that senescent cells mediate the effects of ageing. Hence it follows that to understand ageing, it is necessary to understand cellular senescence. This model of active induction of ageing (via senescent cells) does not exclude the role of stem cell depletion described above, which could indeed be a result of stem cell senescence.

At present, the causes of cellular senescence in vivo are not known for certain but in vitro, cells can become senescent through (i) telomere shortening via exhaustive replication (replicative senescence), (ii) over-expression of oncogene or (iii) DNA damage. While it is easy to perceive replicative senescence (RS) as part of a bona fide mechanism of ageing, it is more challenging to consider oncogene-induced senescence (OIS) as a significant contributor to natural ageing. Instead OIS has been proposed to function as a tumour suppressor mechanism. The only obvious common factor between RS and OIS is the co-opting of the DNA damage signalling mechanism to usher cells into arrest.

Recently, we developed a multivariate estimator of chronological age, referred to as epigenetic clock, based on methylation levels. The following features of this clock demonstrates that its age estimates capture several aspects of biological age: (a) it can accurately measure the age of cells regardless of tissue types including brain, liver, kidney, breast and lung (b) its accuracy is substantially higher than that of other molecular markers such as telomere length (c) it is able to predict mortality independent of health, life-style or genetic factors (d) its measurements correlate with cognitive and physical fitness amongst the elderly and (e) it is able to detect accelerated ageing induced by various factors including obesity, Down syndrome and HIV infection. Here, we apply this epigenetic clock to study the relationship between ageing and senescence of isogenic cells induced by exhaustive replication, ectopic oncogene over-expression or radiation-induced DNA damage.

We show that induction of replicative senescence (RS) and oncogene-induced senescence (OIS) are accompanied by ageing of the cell. However, senescence induced by DNA damage is not, even though RS and OIS activate the cellular DNA damage response pathway. Collectively, these two sets of observation make an effective case for the uncoupling of senescence from cellular ageing. This however, appears at first sight to be inconsistent with the fact that senescent cells contribute to the physical manifestation of organism ageing, as demonstrated elegantly by studies in which removal of senescent cells slowed down ageing. In the light of our observations however, it is proposed that cellular senescence is a state that cells are forced into as a result of external pressures such as DNA damage, ectopic oncogene expression and exhaustive proliferation of cells to replenish those eliminated by external/environmental factors. These senescent cells, in sufficient numbers, will undoubtedly cause the deterioration of tissues, which is interpreted as organism ageing. However, at the cellular level, ageing, as measured by the epigenetic clock, is distinct from senescence. It is an intrinsic mechanism that exists from the birth of the cell and continues. This implies that if cells are not shunted into senescence by the external pressures described above, they would still continue to age. This is consistent with the fact that mice with naturally long telomeres still age and eventually die even though their telomere lengths are far longer than the critical limit, and they age prematurely when their telomeres are forcibly shortened, due to replicative senescence. Hence senescence is a route by which cells exit prematurely from the natural course of cellular ageing.

Finally, it is necessary to address specifically the role of telomeres as it is easy to confound them with cellular ageing because at first view, they appear to share similar features. Since critical telomere length is attained after many rounds of proliferation, which takes a long time and hence occurs later in life, it is easy to mistake this for a functional link with age even though telomere length has only a modest correlation with chronological age, while cellular ageing as measured by the epigenetic clock has a far higher degree of association with biological ageing. The fact that maintenance of telomere length by telomerase did not prevent cellular ageing defines the singular role of telomeres as that of a means by which cells restrict their proliferation to a certain number; which was the function originally ascribed to it. Cellular ageing on the other hand proceeds regardless of telomere length.

Although the characteristics of cellular ageing are still not well known, the remarkable precision with which the epigenetic clock can measure it and correlate it to biological ageing remove any doubt of its existence, distinctiveness and importance. This inevitably raises the question of what is the nature of this cellular ageing, and what are its eventual physical consequences. Admittedly, the observations above do not purport to provide the answer, but they have however, cleared the path to its discovery by unshackling cellular ageing from senescence, telomeres and DNA damage response, hence inviting fresh perspectives into its possible mechanism. In summary, the results from these experiments, while apparently simple in their presentation, untangles a conceptual knot that hitherto tied senescence, DNA damage signalling, ageing and telomeres together in an incomprehensible way. Here we propose that cellular ageing, as measured by the epigenetic clock, is an intrinsic property of cells, and while independent, its speed can be affected by some factors; a feature that would undoubtedly be exploited to characterise and elucidate its mechanism.

Commentary on a Connection Between Mitochondrial Dysfunction and Cellular Senescence

Last year, researchers demonstrated a link between mitochondrial dysfunction and cellular senescence, both implicated as mechanisms of aging. It isn't clear at this stage whether the link demonstrated is relevant in normal aging, as the senescent state produced through induced mitochondrial dysfunction doesn't appear to be the same as that observed in naturally aged tissues, but it is nonetheless quite intriguing. Here is a commentary on that research from one of the scientists involved:

Mitochondria are the primary source of energy (largely in the form of ATP) for most of our cells. They also more closely resemble bacteria than they do other parts of the cell. In fact, they have their own unique genome that, much like bacteria, is circular. Moreover, our mitochondrial DNA acquires mutations much more rapidly than our nuclear genome - due to a combination of weaker DNA repair and close proximity to reactive oxygen species (ROS) produced by respiration. These and other factors result in a state in which mitochondria become less and less functional as we age, a term generically called "mitochondrial dysfunction".

We show that cells with mitochondrial dysfunction undergo cellular senescence - a tumor-suppressive process that permanently halts cell division. However, these senescent cells lack many of the secretory features of the other types of senescence that we and others have studied. Cells that undergo mitochondrial dysfunction-associated senescence (MiDAS) secrete many biologically active factors, but they don't produce many of the typical inflammatory molecules produced by other forms of senescence. Instead, these cells secrete their own unique blend of biologically active factors that prevent adipogenesis and promote skin cell differentiation. In a model of mice that age prematurely due to mitochondrial mutations, MiDAS cells accumulate in fat deposits and skin, causing the mice to lose fat, lose hair, and develop very thin skin as they age.

Mechanistically, MiDAS occurred due to decreased cytosolic NAD+/NADH ratios. Mitochondria oxidize NADH to NAD+ as part of normal respiration, so when mitochondria are compromised NADH levels rise in the cell. As a consequence of lower NAD+/NADH ratios, AMP and ADP rise, leading to activation of AMP-activated protein kinase (AMPK), which then phosphorylates and activates p53 - a major mediator of senescence. Therefore, senescence is a natural outcome of metabolic stress following mitochondrial compromise. NADH can be oxidized by alterative means - and addition of factors such as pyruvate to the culture media allowed mitochondria-independent enzymes to oxidize NADH, restoring the NAD+/NADH ratio. When cultured in the presence of these compounds, cells with mitochondrial dysfunction grew normally and did not senesce. Surprisingly, these non-senescent cells had a secretome that largely resembled the canonical senescence-associated secretory phenotype (SASP)! Upon pyruvate withdrawal, these cells underwent senescence and lost their SASP-like secretome.

Many questions are still unanswered. Do MiDAS cells accumulate during normal aging? If so, where and when do they do so? Are NAD-targeted therapeutics still beneficial if they allow secretion of inflammatory factors? More importantly, can we target these cells to prevent or even cure some of the disorders associated with aging? Now that we know that MiDAS exists, we are positioned to answer these important questions.


Theorizing on Oxidized Cholesterol as a Driving Mechanism for Alzheimer's Disease

There are a growing number of theories on the mechanisms of Alzheimer's disease. The biochemistry of the brain is very complex and still incompletely mapped, and it is cheaper to theorize than it is to build therapies and test them, so the theorizing is always going to be far more extensive and diverse than ongoing efforts to treat the condition. This is especially true since the consensus efforts based on clearing amyloid from the brain have yet to produce compelling results in trials. It is unclear as to whether this is because it is a difficult challenge, even for the present state of biotechnology, or because it isn't yet the right direction.

This theory focuses on rising levels of oxidative damage to lipids and cholesterols, a process that plays an important role in other age-related disease, such as atherosclerosis. These oxidized molecules can spread throughout the body via the bloodstream, allowing inflammation and generation of reactive oxidizing molecules caused by scattered damaged or senescent cells to contribute to aging everywhere.

Alzheimer's disease (AD), the most common neurodegenerative disorder associated with dementia, is typified by the pathological accumulation of amyloid Aβ peptides and neurofibrillary tangles (NFT) within the brain. Considerable evidence indicates that many events contribute to AD progression, including oxidative stress, inflammation, and altered cholesterol metabolism. The brain's high lipid content makes it particularly vulnerable to oxidative species, with the consequent enhancement of lipid peroxidation and cholesterol oxidation, and the subsequent formation of end products, mainly 4-hydroxynonenal and oxysterols, respectively from the two processes.

The chronic inflammatory events observed in the AD brain include activation of microglia and astrocytes, together with enhancement of inflammatory molecule and free radical release. Along with glial cells, neurons themselves have been found to contribute to neuroinflammation in the AD brain, by serving as sources of inflammatory mediators. Oxidative stress is intimately associated with neuroinflammation, and a vicious circle has been found to connect oxidative stress and inflammation in AD. Alongside oxidative stress and inflammation, altered cholesterol metabolism and hypercholesterolemia also significantly contribute to neuronal damage and to progression of AD. Increasing evidence is now consolidating the hypothesis that oxidized cholesterol is the driving force behind the development of AD, and that oxysterols are the link connecting the disease to altered cholesterol metabolism in the brain and hypercholesterolemia; this is because of the ability of oxysterols, unlike cholesterol, to cross the blood brain barrier. The key role of oxysterols in AD pathogenesis has been strongly supported by research pointing to their involvement in modulating neuroinflammation, Aβ accumulation, and cell death.


The Global Healthspan Policy Institute Wants Your Support in Lobbying for TAME Metformin Trial Funding

The Global Healthspan Policy Institute (GHPI) is a recently launched group whose principals are focused on much the same goals as the researchers of the Longevity Dividend initiative, which is to say pulling a lot more public funding into aging research aimed at extending healthy human life spans. The chosen methodology is the traditional one of lobbying and political action, aimed at politicians and bureaucrats who influence budgets relevant to the National Institutes of Health, the National Insitute on Aging in particular, and other public sources of medical research funding.

The first public initiative for the GHPI is to petition and lobby for political support and public funding for the proposed TAME human trial of metformin as a drug to treat aging. The expectation that this will produce meaningful results in terms of extended health seems low to me, unfortunately: the animal study evidence for metformin to influence aging is scattered, contradictory, and terrible. This drug is, however, very safe, already approved, and widely used for decades. Arguably the real purpose of this exercise is to push the FDA into accepting a trial for a treatment aimed explicitly at intervention in aging rather than the treatment of any specific disease, using a vehicle - metformin - that regulators can't possibly object to on other grounds. Then the door stands open to anyone else with a potential therapy to treat the causes of aging. The FDA is otherwise a roadblock for all who wish to work within the US regulatory system, as its bureaucrats have up until this point not recognized aging as a medical condition and thus blocked any possible treatments for aging from entering the approval process. This in turn echoes back down the chain of research and development to make raising funding very challenging.

Ask Congress to Fund the First FDA-Approved Drug Trial to Prevent Cancer and Other Diseases of Aging

Aging brings illness. All of our major diseases get worse as we age, including heart disease, cancer, arthritis, dementia, cataract, osteoporosis, diabetes, hypertension, and Alzheimer's disease. Now for the first time in history, the US Food and Drug Administration has approved human testing of a drug to slow human aging that would decrease the risk for all of these illnesses, dramatically lowering healthcare costs and boosting quality of life for the elderly. Named "one of the most innovative projects of the year" by the Washington Post and the subject of the hit Ron Howard documentary "The Age of Aging", the TAME/Metformin study would take place in research centers nationwide.

Unfortunately, this study will not be funded by drug companies. Metformin has a long history treating diabetes, so it is known to be safe, but its also past the early phase where a drug company will invest in a drug because it can own it and profit by it. So the only way for this landmark drug trial to move forward is to be funded by Congress, much like they have funded thousands of other studies. The Global Healthspan Policy Institute is leading this charge. We are a non-profit think tank and policy institute that does not represent any government agency, corporation, or medical center. We have many allies in Congress who love the project, but we need your help with specific members of Congress whose position on appropriations committees can make or break this movement.

Petition: Tell Congress to Fund Critical Healthspan Research

Right now, the federal government spends billions each year in medical research seeking to cure one disease at a time - while virtually ignoring the underlying processes that eventually lead to a whole host of fatal diseases. It is estimated that 75 percent of the $1.9 trillion spent on all health care in the United States stems from preventable chronic health conditions - but only 1 percent is allocated to protecting health and preventing illness.

Every year Congress sets the Department of Defense's budget, which contains a "Peer Reviewed Medical Research Program" just for research like the TAME/Metformin drug trial. Join us in asking Congress to allocate funds. To get started they need $13 million per year for the first two years for the TAME/Metformin study that will span 6 years for a total cost of $64 million. Funding will be given to 14 university locations around the country - including possibly in your state - that will study a total of 3,000 people.

Let's plant the seeds for a future where we can all have more healthy, productive years of life - where major diseases can be stopped before they ever begin, and no one has to shoulder the burden of rising healthcare costs. Tell your representative today!

I'm sure you all know my opinions on engaging with a broken system of regulation and on metformin by now, so I won't do more than summarize. I think that the damage done to the pace of progress by the FDA is best fought by avoiding that agency so as to make it irrelevant, not by legitimizing it through engagement, and the best way to do this is for treatments to be deployed to clinics outside the US and accessed via medical tourism, just as happened for stem cell medicine. More bluntly, I see work on metformin in connection with aging as a waste of effort. It is a comparatively bad choice, as compared to, say, rapamycin analogs, within what is itself a comparatively bad class of initiatives to treat aging, mining existing drugs to find those capable of marginally slowing the aging process. This approach is both expensive and capable of producing at best poor results that are of little use to people already old and damaged. It boggles the mind that so much time and effort is spent on this type of research and development in an age in which senescent cell clearance and other forms of damage repair for living beings, capable in principle of rejuvenation of the old, and already producing much more robust results in animal studies, are in or nearing clinical development.

I understand that I'm in a minority in holding these views, that the majority of the community would rather fight for change within the present system, and that there are people geared up and ready to go with the TAME organizational and lobbying efforts. But if people absolutely must have this fight with the FDA, to expend significant resources to try to change the system from within, I'd rather it was happening two or three years from now for the first trials of senescent cell clearance therapies - a rejuvenation treatment with a high expectation of producing meaningful and reliable benefits in humans, rather than something that I expect to produce results that lie somewhere between nothing and a tiny statistical benefit.

I encourage you all to make up your own minds of course, and you should certainly take a look at what the Global Healthspan Policy Institute is up to, and keep an eye on their progress in the years ahead.

Rejecting the Mistaken Idea that the Defeat of Aging Would Somehow Diminish the Value of Human Life

I wasn't aware that some objectivists use Ayn Rand's thought experiments to support an opposition to extended human longevity. The essay linked here refutes that interpretation, but this is only one facet of a much broader set of arguments - found in or arising from adherents of near every philosophy - made to suggest that aging and death gives human life value, or moral or ethical standing. From this perspective the medical control of aging, and the elimination of pain, suffering and death caused by age-related disease, achieved through technologies such as SENS rejuvenation treatments, would somehow make us all worse off. This is one of many reasons why most philosophical positioning, like the theology it evolved from, isn't worth the paper it is printed on, or the time taken to understand its errors. It is self-evidently ridiculous to argue that less age-related disease and more healthy life diminishes us, and I don't see any of the people making that argument rushing to give up the advantages of present day medicine when it comes to treating age-related disease. Hypocrites, the lot of them. Nonetheless, that is is exactly the position regularly deployed against advocates of greater research and development in longevity science. It is both irrational and, to the extent it harms progress, dangerous for all of us.

Some advocates of Ayn Rand's philosophy believe that indefinite life would turn human beings into "immortal, indestructible robots" that, according to Ayn Rand, would have no genuine values. Both of these claims are false. Indefinite life would not turn humans into indestructible robots, nor would an indestructible robot with human abilities lack values or motivation for doing great things. Rand's "immortal robot" argument is found in "The Objectivist Ethics": "To make this point fully clear, try to imagine an immortal, indestructible robot, an entity which moves and acts, but which cannot be affected by anything, which cannot be changed in any respect, which cannot be damaged, injured or destroyed. Such an entity would not be able to have any values; it would have nothing to gain or to lose; it could not regard anything as for or against it, as serving or threatening its welfare, as fulfilling or frustrating its interests. It could have no interests and no goals."

First, at no point in time will human beings become "immortal, indestructible robots". The simple reason for this is that our existence is physical and contingent on certain physical prerequisites being fulfilled. The moment one of these physical prerequisites is lacking, our existence ceases. This will always be the case, even if we no longer have a necessary upper limit on our lifespans. For instance, biomedical advances that would greatly expand human lifespans - allowing periodic reversions to a more youthful biological state and therefore the possibility of an indefinite existence - would not turn humans into indestructible robots. There would still be the need to actively turn back biological processes of decay, and the active choice to pursue such treatments or not. People who live longer by successfully combating senescence could still get run over by a car or experience a plane crash.

Moreover, the need to reject the "immortal robot" argument when discussing indefinite life extension does not stem solely from a desire to achieve philosophical correctness. Rather, we should recognize the potential for actually achieving meaningful, unprecedented longevity increases within our own lifetimes. Thus, it is premature to conclude that death is a certainty for those who are alive today. Medical advances on the horizon could indeed turn many humans into beings who are still potentially vulnerable to death, but no longer subject to any upper limit on their lifespans.

It is therefore ill-advised to pin any ethical justifications for the ultimate value of human life to the current contingent situation, where it just so happens that human lifespans are finite because we have not achieved the level of technological advancement to overcome senescence yet. If such advances are achieved, common interpretations of the "immortal robot" argument and its derivative claims would suggest that life for human beings would transform from an ultimate value to some lesser value or to no value at all. This implication reveals a flaw in arguments that rely on the finitude of life and the inevitability of death. How is it that, by making life longer, healthier, and of higher quality (with less suffering due to the diseases of old age), humans would, in so doing, deprive life of its status as an ultimate value? If life is improved, it does not thereby lose a moral status that it previously possessed.

But suppose that a true immortal, indestructible robot could exist and be identical to human beings in every other respect. Even if death were not a possibility for such a being, it could still pursue and enjoy art, music, inventions, games - any activity that is appealing from the perspective of the senses, the intellect, or the general civilizing project of transforming chaos into order and transforming simpler orders into more complex ones.

The fear of death is not the sole motivator for human actions by far. Indeed, most great human accomplishments are a result of positive, not negative motivations. I concur fully with the goal of a full life, of flourishing, and recognize the existence of numerous positive motivations besides mere survival. For example, the desire to see oneself create something, to witness a product of one's mind become embodied in the physical reality, is a powerful motivation indeed. One can furthermore seek to take aesthetic pleasure from a particular object or activity. This does not require even a thought of death. Creating art and music, undertaking scientific discoveries, envisioning new worlds - actual and fictional - does not rely on having to die in the future. None of these activities even rely on the threat of death. Life is not merely about survival and should be about the pursuit of individual flourishing as well. Survival is a necessary prerequisite, but, once it is achieved, an individual is free to pursue higher-order values, such as self-actualization. The individual would only be further empowered in the quest for flourishing and self-actualization in a hypothetical environment where no threats to survival existed.


Existing Drug Found to Slow Progression of Transthyretin Amyloidosis

Researchers have discovered that an existing drug can slow the progression of rare forms of transthyretin amyloidosis caused by mutation by interfering in the formation of this type of amyloid. It is unclear as to how useful this would be in practice for the age-related accumulation of transthyretin amyloid known as senile systemic amyloidosis that occurs in every individual, however, as that happens at a much slower pace over a greater span of time. The growing presence of this amyloid is implicated in a range of age-related conditions, particular cardiovascular disease. The ideal approach to amyloidosis, whether age-related or not, is clearance of amyloid rather than slowing its formation, however. Clearance can be applied at any point in the progression of the amyloidosis to obtain benefits, and applied repeated as needed, at a much lower cost. Slowing progression requires constant treatment at a much higher cost, and produces smaller and diminishing benefits. Fortunately a therapy capable of transthyretin amyloid has already been successful in a small trial, though the pace of clinical development in this field is, as ever, glacial.

Researchers have published the results of a drug repositioning study in which they describe a powerful drug, SOM0226 (tolcapone) that could significantly improve the pharmacological treatment of familial transthyretin amyloidosis (ATTR). ATTR is a rare degenerative disease that mainly affects the nervous system and heart muscle tissue (myocardium), and which is usually passed on from parents to children. It originates when the liver and other areas of the organism produce mutations of the protein transthyretin (TTR), which lose their functional structure. This causes toxic aggregates of amyloid fibres to build up, which, depending on the mutation involved, are deposited in different organs, such as the brain, the kidneys, the nerves, the eyes, or the myocardium, causing them to malfunction and bringing on the various forms of the disease. To prevent the disease from progressing, a liver transplant or liver and heart transplant is needed.

The researchers conducted trials in vitro in cell cultures and ex vivo in human plasma and in mouse models of the disease to show that tolcapone is a powerful inhibitor of the aggregation of amyloid fibres by TTR. Tolcapone acts by imitating the process by which the thyroid hormone - T4 or thyroxine - binds to TTR in the bloodstream. Just like the hormone, the drug binds closely to the protein, tying together the four protein sub-units that form the protein's structure. This binding has been proven to stabilise the protein, preventing the sub-units from separating and then forming aggregates. This is a hitherto unknown property of the drug, which is used to treat Parkinson's disease. The compound turns out to be four times more effective than the only medicine currently available for treating the polyneuropathic variant of ATTR. The results were positive for all variants of the disease that were studied: familial amyloid polyneuropathy and cardiomyopathy (which affects the peripheral nerves and the myocardium, respectively) and senile systemic amyloidosis, a sporadic form that appears in a very high percentage of men over 60 years of age (and also affects the myocardium). In addition, the treatment was shown to cross the blood-brain barrier, making it the first to tackle the variants that affect the central nervous system.

According to the researchers, this molecule has the potential to become an effective drug for preventing the protein depositions that cause the disease and slowing down its progress, one that could be on the market within five years, as it has already been tested in a clinical trial with persons affected by the neuropathic variant.


A Little Backstory for UNITY Biotechnology

UNITY Biotechnology made a big splash a few weeks ago to announce their venture funding and intent to develop a senescent cell clearance technology to treat age-related disease by removing one of its causes. The press linked the company to researchers involved in proof of concept work in mice that has been ongoing since 2011, using a clever system of genetic engineering to eliminate senescent cells first in an accelerated aging mouse lineage and then in mice that age normally. This culminated in a life span study showing 25% life extension in mice through this methodology, which clearly sets the stage for much greater interest in this approach to the treatment of aging as a medical condition. This is good news all round, since Strategies for Engineered Negligible Senescence (SENS) advocates and researchers have been calling for progress towards senescent cell clearance for more than a decade, and now the rest of the research community is finally catching up.

UNITY Biotechnology didn't emerge from nothing, and isn't just an outgrowth of the particular research group noted in the press material. It is more a union between that group, Buck Institute researchers who have been working on the same challenge, and a preexisting commercial venture with its own potential technology for senescent cell clearance. This makes sense, as the genetic engineering approach used in mice as a proof of concept would essentially have to be ripped up and rebuilt from scratch in order to be useful in humans. That is a poor alternative if there is some other approach to build on instead. As I pointed out last year, if you go digging there is a lot of dark matter out there from the past ten years when it comes to efforts to clear senescent cells. There are patents on a variety of approaches, and a number of dead, quiet, or dormant small companies that clearly never got to the point at which they could convince the venture community to fund their work.

One of these companies is Cenexys, started by the same successful entrepreneur who is at the helm of UNITY Biotechnology. There are relationships there with established biotechnology company Kythera Biopharmaceuticals, and with the Buck Institute group run by Judith Campisi where a lot of senescent cell work has taken place in recent years. Cenexys was probably just a holding company for the senescent cell clearance intellectual property: if you take a look at relevant patent registrations, you'll find the following patents, and note that they are now assigned to UNITY Biotechnology.

Use of engineered viruses to specifically kill senescent cells (2013)

Polypeptides, viruses, methods and compositions provided herein are useful for the selective elimination of senescent cells. Method aspects include methods for inducing apoptosis in a senescent cell comprising administering to the cell a polynucleotide, virus, host cell, or pharmaceutical composition described herein. Other methods include expressing a pro-apoptotic gene in a senescent cell comprising administering to the cell the polynucleotide, virus, or pharmaceutical composition as described herein.

Immunogenic compositions for inducing an immune response for elimination of senescent cells (2013)

Provided herein are immunogenic compositions (vaccines) and methods for immunizing a subject with the immunogenic compositions for inducing an adaptive immune response directed specifically against senescent cells for treatment and prophylaxis of age-related diseases and disorders, and other diseases and disorders associated with or exacerbated by the presence of senescent cells. The immunogenic compositions provided herein comprise at least one or more senescent cell-associated antigens, polynucleotides encoding senescent cell-associated antigens, and recombinant expression vectors comprising the polynucleotides for use in administering to a subject in need thereof.

Compositions and methods for detecting or eliminating senescent cells to diagnose or treat disease (2014)

Disclosed are agents (e.g., peptides, polypeptides, proteins, small molecules, antibodies, and antibody fragments that target senescent cells) and methods of their use for imaging senescent cells in vivo and for treating or preventing cancer, age-related disease, tobacco-related disease, or other diseases and disorders related to or caused by cellular senescence in a mammal. The methods include administering one or more of the agents of the invention to a mammal, e.g., a human. The agents, which specifically bind to senescent cells, can be labeled with a radioactive label or a therapeutic label, e.g., a cytotoxic agent.

UNITY Biotechnology is the brand under which the final assembly of technology, money, and will for this line of research came together, after some years of groundwork, which clearly involved filing (arguably overly) broad patents on anything that looked promising. At any point in time over the past five years someone could have funded a senescent cell clearance approach and started good work on making it real. Things are always late, however, coming together well past the point at which they are obvious to many in the industry, especially when you have to convince outsiders to give you venture funding. This is why it is very rare for any company to emerge alone, and UNITY Biotechnology is only one of a number of efforts. There are competitors I know about, such as Oisin Biotechnologies whose founders have assembled an impressive gene therapy approach, and no doubt competitors I don't know about because they are either quiet groups internal to Big Pharma entities, or scientists elsewhere in the world with nascent senescent cell clearance technology and the connections to launch a company sometime in the next year or two.

The breadth of these patents unfortunately doesn't give much of an indication as to what exactly the UNITY Biotechnology staff is working on for their first attempt at a senescent cell clearance technology, other than to suggest that they are indeed doing nothing with the genetic engineering proof of concept used in the mouse life span studies. Tagging senescent cells and then sending engineered immune cells to destroy them wouldn't be a terrible guess, however. Immunotherapy is certainly a very viable approach to targeted cell destruction; a lot of time and effort goes toward this sort of immunotherapy in the cancer research community, for example.

An Improved System for Testing Lipofuscin Removal

A team funded by the SENS Research Foundation has developed an improved system for evaluating methods of lipofuscin removal in cells. Lipofuscin, a mix of many different forms of hardy metabolic waste, builds up in tissues with age. It clogs up lysosomes, the cellular recycling units, causing them to become bloated and dysfunctional. As all forms of cellular garbage accumulate due to this issue, cells themselves become dysfunctional or die. This is a significant and damaging problem in long-lived cell populations, such as those of the central nervous system. The compounds involved in the lipofuscin mix found in the retina, for example, directly contribute to the progressive age-related blindness caused by macular degeneration. Elsewhere in the body lipofuscin accumulation is implicated in the pathology of a range of age-related diseases. Clearing these waste compounds is an important goal in the development of rejuvenation therapies to treat aging by addressing its root causes.

Lipofuscin accumulation has an inverse relationship with lifespan and is a well-documented hallmark of aging. Many age-related disease states including Alzheimer's, Parkinson's, and age-related macular degeneration show increased lipofuscin accumulation. Some organisms accumulate lipofuscin in a nearly linear manner over time, and therefore their age is determined using methods that quantify lipofuscin levels. Two primary theories have been proposed for lipofuscin formation: the mitochondrial-lysosomal axis theory of aging and the protease inhibitor model of aging. The former focuses on irreparable oxidative damage caused by oxygen-driven Fenton reactions associated with mitochondrial processes, while the latter espouses inadequate lysosomal proteolysis as a cause of aging. Both theories have significant merit and lend credence to the 'garbage catastrophe' theory of aging, which states that the buildup of recalcitrant nondegradable material within the cell eventually leads to cell senescence or inhibited function.

Since lipofuscin accumulation impairs proteosome and lysosome pathways critical to cell health and homeostasis, the ability to quickly generate lipofuscin in vitro, and identify drugs that mitigate the accumulation or clear lipofuscin would be of great benefit to aging research. Here, we present a platform to quickly create lipofuscin-loaded but otherwise healthy cells and screen drugs for efficacy in lipofuscin removal. The combination of leupeptin, iron (III) chloride and hydrogen peroxide generates significant amounts of lipofuscin within cells while eliminating the need for a 40% hyperoxic chamber required by another existing protocol for lipofuscin generation. Alternative methods which load fibroblasts with "artificial" lipofuscin obtained via UV-peroxidation of mitochondrial fragments are much more labor-intensive. This method is faster (≤10 days) than most protocols to generate lipofuscin and assess its removal, which typically require 2 to 4 weeks or longer to complete.


Regenerating the Thymus to Treat Age-Related Autoimmunity

Autoimmune diseases are caused by a range of malfunctions in the configuration of the immune system that lead it to attack the patient's own tissues, causing chronic inflammation at the least and eventually fatal damage at the worst. Most incidence of autoimmune disease is not very age-related, but aging does bring a rising level of autoimmunity as the immune system becomes increasingly dysfunctional and ineffective, falling into the state known as immunosenescence. One contributing cause of immune aging is a limited and diminishing supply of new immune cells, and one potential approach to treatment is to restore the thymus so as to increase the pace of production of immune cells:

We tend to focus on rejuvenating the aging immune system's specific immunity to pathogens because the loss of this ability is more often acutely life-threatening, as can be seen in the terrifying rise of influenza-associated pneumonia hospitalization and death rates beginning around age 65. But there is also a substantial rise in autoimmunity with age, leading to greater incidence of specific autoimmune diseases such as rheumatoid arthritis and lupus, along with a less specific rise in autoimmune reactivity in the aging immune system, which is seen in the rising frequency of autoantibodies even in people with no overt autoimmune disorder. These may be linked to the rising inflammatory tone with age, and possibly to the increase in cancer, atherosclerosis, and neurodegeneration with age. While their effects are incomplete and not without side-effects, existing models of slow aging already show us that the age-related rise in autoimmunity is modifiable. Both laboratory rodents subjected to calorie restriction (a strong model of slow aging, at least in mice and rats) and human centenarians enjoy rates of autoimmune antibodies and disease that resemble those of controls with much lower calendar ages.

One key to rejuvenating the aging immune system and eliminating the autoimmunity of aging is engineering biologically young thymus tissue to supplement or supplant the shrunken and structurally-damaged ("involuted") aging thymus. The young, healthy thymus prevents autoimmunity in two ways. First, it screens newly-matured T-cells and eliminates any that target "self" proteins in a process known as negative selection. Recently, researchers created mice whose thymuses decayed more rapidly than normal with age by gradually eliminating a gene (FoxN1) that is involved in maturing and maintaining the organ. This accelerated thymic involution resulted in the release of high numbers of autoreactive T-cells from the thymus, which rapidly became activated and began attacking body tissues, leading to increased inflammation. The scientists traced this back to an impairment of the activity of a protein involved in negative selection, and the involuted thymus tissue's inability to recruit the innate immune cells needed to present the thymus with the tissue-specific self-antigens needed to screen out the harmful self-reactive cells. Engineered young thymic tissue grafts would restore the youthful thymus' strong capacity for negative selection.

Additionally, aging people suffer a loss of regulatory T cells (Tregs), also known as suppressor T cells, which help to enforce tolerance to "self" antigens. One possible cause of this is the sheer failure of the involuted thymus to generate sufficient total numbers of T-cells, a subset of which go on to become Tregs. If so, then engineered youthful thymic tissue will reverse that deficit.

But an additional, non-exclusive cause of the loss of Tregs with age is that they may be crowded out by rising clones of dysfunctional T-cells with age. If so, then rejuvenation biotechnology to ablate these "anergic" T-cells might make room to allow the body to restore their numbers, just as it is expected to do for killer T-cells directed at new pathogens. The technology required to eliminate such cells (such as a mature version of the prototype "T-cell scrubber" developed by researchers with SENS Research Foundation and now being adapted as part of Foundation-funded work to rejuvenate the aging systemic environment) could potentially also be turned directly on the self-reactive T-cell clones themselves, purging them from the body even as other aspects of immune aging are reversed by other rejuvenation biotechnologies. Very similar technology could also be applied to clearing out autoreactive B-cell clones, which are essential for autoantibody production and for perpetuation of the autoimmune response. There is, indeed, already proof-of-concept work in ablating aged B-cell clones as rejuvenation biotechnology for humoral immunity. Depending on the full fruits of other rejuvenation therapies, these techniques might need to be periodically reapplied, and could also potentially be used to suppress hereditary and other non-age-related causes of autoimmunity.


Engaging the Elephant: the SENS Research Foundation on the Need for Debate on Rejuvenation Research

The latest newsletter from the SENS Research Foundation turned up in my in-box today, and includes some interesting thoughts on advocacy. The SENS Research Foundation remains one of the best and most effective of organizations dedicated to bringing about the creation of therapies capable of greatly extending the healthy human life span - in fact, therapies capable in principle of rejuvenation, turning back the clock by repairing the forms of cell and tissue damage that cause aging. Other organizations, like Calico, are investing vastly more money, but since they aren't funding the right sort of scientific programs, they may as well not exist. Their only value lies in the fact that they may, later, choose to adopt approaches based on repair of cell and tissue damage that SENS-funded and SENS-encouraged research groups demonstrate to be effective, such as senescent cell clearance.

It is frustrating to see such potential sitting right at the sideline, flirting with doing something useful yet not crossing that line, but that is sadly the way things work in longevity science. The overwhelming majority of funding and effort is devoted to metabolic tinkering - such as work on calorie restriction mimetics - that cannot possibly produce meaningful gains in human life span, while programs that can in principle produce indefinite healthy life spans must struggle to gain even a small amount of funding.

The SENS approach of damage repair to reverse aging rather than metabolic manipulation to slow aging is nonetheless slowly gaining ground in this challenge for support and adoption. This is illustrated by, among other things, the fact that there is now more than one venture funded company working on aspects of SENS rejuvenation biotechnology. Nonetheless, there is still a long way to go towards the goal of the mass adoption of SENS research and development goals by a large swathe of the research community, and the goal of the same public support for the defeat of aging as there is for the defeat of cancer. Advocacy for this cause remains very important and very much needed.

SENS Research Foundation Newsletter, February 22, 2016

On January 19, 2016, Intelligence Squared hosted a debate on the motion: "Lifespans Are Long Enough". Arguing for the motion were Ian Ground, a Philosopher and Lecturer at the University of Newcastle, and Paul Root Wolpe, Director, Emory Center for Ethics. Arguing against the motion were Aubrey de Grey, Chief Science Officer of SENS Research Foundation, and Brian Kennedy, CEO and President of the Buck Institute for Research on Aging.

At SENS Research Foundation, we know that the tragic lack of funding for damage-repair-oriented research into these conditions is in part due to simple lack of awareness, which is why one major goal of SENS Research Foundation's outreach program is to increase global awareness of the potential of our approach. We also know that the vast majority of humanity is on our side when it comes to changing the way the world researches and treats age-related disease. The amount of time and money already going into attempts to mitigate diseases like Alzheimer's speaks volumes here. Anyone who has watched the deterioration of a beloved family member, or had to address caregiving needs for a person suffering from dementia, or seen the sadness and frustration of a loved one losing one ability after another as every life activity becomes a source of pain would jump at the chance to provide genuine relief for age-related maladies to those they care about.

That said, some people still maintain an abstract objection to the very notion of living beyond what they consider a 'natural' lifespan. This puts a damper on their enthusiasm for programs like SENS Research Foundation's, which, if successful, could result in more people living longer as an incidental effect of the rejuvenation biotechnologies that protect them from sickness and frailty. Some individuals are uncomfortable with this scenario. We want to reach these people too, and perhaps introduce them to points of view they may not have considered before, in the hopes they might come to see that we all ultimately want the same thing: a world with the least possible amount of needless suffering.

This recent Intelligence Squared debate in particular did a great job of engaging the 'elephant in the room' we often contend with in our attempts to communicate our mission and goals to a wider audience, i.e., the fact that fixing age-related disease will necessarily mean fewer people 'dying of old age'. More to the point, longer healthspan may be inextricable from longer lifespan due to simple biological realities.

It is up to each person to determine their position on this matter, but from the standpoint of our work, SENS Research Foundation maintains that it is an ethical imperative to prevent the undeniable suffering caused by age-related disease. We don't expect to cure disease through debate, but participating in these events can be a great way to introduce people to new perspectives - perhaps even ones that change their minds and encourage them to support our research. Speaking of supporting our research, remember that as a 501(c)(3) public charity, SRF depends on you to help enable critical research, as well as our education and outreach programs. Please consider making a generous contribution today.

Many Methods of Modestly Slowing Aging in Laboratory Species are Gender Specific

Over the past twenty years researchers have demonstrated a great many ways to slightly slow aging in short-lived laboratory species: flies, worms, and mice. As a general rule these are largely irrelevant to the future of human longevity, however. They are adjustments to the operation of metabolism, something that is expensive and challenging to understand well enough to do safely in humans, and the beneficial effects are small (and in many cases unreliable and disputed) even when operating over the entire life span. Trying to make human therapies of these results is a dead end in comparison to the approach of repairing age-related cell and tissue damage. Many of the methods of slightly slowing aging through metabolic alterations produce different results in males and females, which is probably to be expected given that there are differences in metabolism between the genders that are at least as large as the changes produced by some of these interventions.

Analyzing years of previous research on dietary and pharmaceutical tests on flies and mice, researchers showed that aging interventions can have opposite effects on mortality rates in males versus females. The findings appear consistent with data gathered on humans as well. Researchers found that treating flies with the steroid hormone mifespristone/RU486 (used in humans for terminating pregnancy) decreased egg production in females while increasing longevity. Similar effects were seen by tweaking the diets of flies and mice, but the effects were sometimes opposite in males versus females.

Increasing life span also increased the acceleration of age-dependent mortality rate of the population. That's evidence of a strong Strehler-Mildvan relationship, which is described by the Gompertz equation, a model for mortality named for the British mathematician who first suggested it in 1825. Here's what that means: Suppose you could create a graph of the mortality rate of everyone born in a single year - from birth until the last person died. You'd see two key things: Off the bat, there'd be a small number of individuals dying here and there - typically due to infections and pathogens. That's non-age-driven mortality. Then, as the group aged, you'd see the mortality rate rise exponentially until the last person died. This acceleration is thought to represent true aging - the inexplicable breakdown of the body over time. "We all speculate, but no one has really figured out what the cause of that acceleration is. Our results show that dietary and genetic interventions sometimes have opposite effects on that acceleration in males versus females."

What the Strehler-Mildvan relationship implies is that this equation is affected by the mixture of strong and frail individuals in a population - and that if you tweak the mixture, the mortality rates will adjust accordingly. "There are weaker, low-vitality individuals in the population and if you kill them off, you're left with high-vitality individuals and the population has a slow mortality acceleration with age. The relationship was so striking in how robust it was in the data we analyzed. I've never seen numbers like that. It confirms that this is a very fundamental relationship."

The findings would also seem to support the antagonistic pleiotropy model for aging, proposed in 1957. Pleiotropy refers to a single gene that affects multiple physical characteristics. In part, the model tries to explain why our bodies ultimately break down and die. Natural selection might select for a gene that creates a fatal flaw later in life if it offers some significant benefit earlier -- that is, if it helps individuals reproduce successfully, it's beneficial to the species even if it does ultimately shorten the individual's life span. The mifespristone intervention appears to prevent such a trade-off between life span and reproductive ability - albeit, a sex-dependent one.


GDF11 Levels Correlate with Mouse Strain Life Spans and are Strongly Heritable

Growth differentiation factor 11 (GDF11) is a protein that appears connected to regulation of stem cell activity in response to rising levels of cell and tissue damage that occur with aging. GDF11 levels fall with aging, as does stem cell activity, and increased GDF11 has been shown to increase stem cell activity in aged mice, producing benefits to health and organ function. There is still some debate over exactly what is going on under the hood in the GDF11 studies carried out to date, and whether researchers are correctly interpreting the results, however. A number of groups are presently exploring the molecular and genetic mechanisms that determine variations in GDF11 levels, with an eye towards the goal of therapies that can compensate for falling levels in aged individuals, and here is news of recent research on this topic:

Previous studies have found that blood levels of this hormone, growth differentiation factor 11, decrease over time. Restoration of GDF11 reverses cardiovascular aging in old mice and leads to muscle and brain rejuvenation. Scientists have now discovered that levels of this hormone are determined by genetics, representing another potential mechanism by which aging is encoded in the genome. Future studies will seek to reveal why GDF11 levels decrease later in life and whether they can be sustained to prevent disease. "Finding that GDF11 levels are under genetic control is of significant interest. Since it is under genetic control, we can find the genes responsible for GDF11 levels and its changes with age."

The study confirmed results from previous experiments showing that GDF11 levels decrease over time and also showed that most of the depletion occurs by middle age. In addition, the study examined the relationship between GDF11 levels and markers of aging such as lifespan in 22 genetically diverse inbred mice strains. Of note, the strains with the highest GDF11 levels tended to live the longest. Using gene mapping, the researchers then identified seven candidate genes that may determine blood GDF11 concentrations at middle age, demonstrating for the first time that GDF11 levels are highly heritable. "Essentially, we found a missing piece of the aging/genetics puzzle. Very generally, we've made an important step toward learning about aging and why we age and what are the pathways that drive it. It's the first step down a long road, but it's an important step."


An Interview with Researcher David Spiegel on the Development of Glucosepane Cross-Link Breakers

The Longecity community leadership runs a regular podcast series, interviewing notable advocates and researchers in the longevity science community. The latest podcast is a discussion with researcher David Spiegel at Yale on the topic of glucosepane cross-link breaking. His research group, funded in part by the SENS Research Foundation, is working towards the means to remove glucosepane cross-link accumulation as a contributing cause of aging. Loss of tissue elasticity lies at the root of arterial stiffening, hypertension, and cardiovascular disease, for example, but this is only one of many problems caused by the growing numbers of persistent cross-links in old tissues. You can look back in the Fight Aging! archives for a long post from earlier this year that outlines the present state of research in this field, so I won't cover the same ground here, but rather skip straight to the podcast transcript:

Justin Loew: Welcome back to Longecity Now. Some of you have been following the SENS theory of aging for over a decade now, and might be wondering if there is any progress. The answer is "yes", as we learned from a podcast with Aubrey de Grey late last year. In that interview Aubrey mentioned the artificial synthesis of glucosepane had recently been achieved. This is important because glucosepane is suspected be a significant culprit in aging tissues. In this edition we hear from the head of the lab that artificially created glucosepane. For those of you who are dying to hear more of the technical details of aging interventions, this interview with David Spiegel should satisfy your curiosity.

David Spiegel: Hello! Great to be here.

Justin Loew: As a little background, how did you come to be interested in synthetic chemistry? Was it mostly scientific curiosity, or was it a determination to cure human diseases?

David Spiegel: So, it's funny, I often get asked this question. I was probably a six-year-old kid, asked in second grade what I thought I would be doing in the year 2000, at the time still 21 years away. I still have the document in which I wrote that I wanted to be a chemist in a drug company. And so, I have stayed pretty true to that vision for my life. I have always been fascinated by molecules, and the fact that simple chemical matter has profound changes on human beings. So chemistry was a natural outgrowth of that interest, and in particular the idea that I could rationally design drugs to do things that nobody else had thought a drug could do. So that has led to research interests in my lab, one of which is in the area of immunotherapeutics, new kinds of molecules that can manipulate the immune system, to do interesting and cool things there. Also, the idea that drugs, small molecules, can be useful in reversal of the aging process.

Justin Loew: Your synthetic chemistry lab made headlines last year for synthesizing glucosepane. Many listeners are familiar with the theory that glucosepane is possibly a significant contributer to the aging process, being an extracellular cross-linking molecule that stiffens tissues, but most less familiar with the reasons why it is so difficult to do anything about it. Why has science been so stymied in regards to this molecule, even though it has been known for decades.

David Spiegel: Yes, it is a good question. So, it is a very difficult molecule to make. Well, two issues: first it is very difficult molecule to make, but also it is actually a difficult molecule to isolate. So even though it is found in all of us, it is found in our tissues, our bones, trying to isolate it in a pure form from the human body is incredibly difficult. Only very small quantities are obtained, and the compounds isolated are actually mixtures of very similar stereoisomers, a kind of different versions of glucosepane that simply can't be separated. So from my perspective I thought it would be quite valuable to take on this challenge, and that is really one of the main areas of focus for my laboratory, which is making very difficult molecules using techniques in organic chemistry. So in my mind, this is something that believed in for a long time. For glucosepane, it is a perfect marriage of interesting chemistry and incredibly interesting biology. The biology here is hard, and people have had a hard time, as you said, studying glucosepane, and of course making it has proven an incredibly difficult challenge because of its complex and intricate chemical structure. So we've been very interested in making it, and now we're in the phase of seeing what we can do with it, particularly with the goal of breaking glucosepane, or developing agents that can break glucosepane, that we think can actually reverse the pathology associated with aging.

Justin Loew: And on that, to add to the pathology aging, do you have any idea on how big of a role glucosepane plays in the aging process?

David Spiegel: You know, there is certainly a lot of evidence indicating that glucosepane levels correlate with organ damage and diseases like diabetes, and there is an argument that in diabetes one of the hallmark features is a kind of accelerated aging of the tissues. Also in people who are simply older, in people greater than 65 years of age, it turns out that there is more glucosepane found in collage than there are enzyme-catalyzed cross-links, the cross-links that are actually supposed to be there are outnumbered by glucosepane. It is these very tissues that are involved in the disease of old age. So collagen-containing tissues include blood vessels, bones, joints, and what do we see in old age? We see cardiovascular disease, we see joint disease, we see renal disease, often. So there is a lot of correlative evidence that is backed by with reasonable mechanistic speculation about a causative role that glucosepane can play, that I think really does implicate it as a key factor in what we term the pathophysiology, the damage, the disease, the element of old age that is a disease.

Justin Loew: Now that you made the molecule, and are looking at breaking the molecule, do you have any estimate of how long it might be before there is an effective therapy that addresses glucosepane?

David Spiegel: That's a good question. I think that from the standpoint of basic research, we've already made some progress in identifying some potential strategies for breaking glucosepane. As you know, there is a significant regulatory challenge associated with bringing new therapeutics to market, and so if I had to estimate - well, this is a very high bar in terms of ... well it is an extraordinary challenge, just the idea of making therapeutics that can break a molecule is kind of an untested concept. But the progress we are making, and the surge of interest right now in protein and enzyme-based therapeutics in pharma, makes me speculate that it is possible we could have something that is therapeutically viable on the order of 10-20 years from now. That may not seem like a short time, but from a therapeutics perspective, I think it is within our kind of vision.

Justin Loew: Staying on that kind of thought there, that the breaking of glucosepane cross-links could be very important for aging research, some people think that cross-link breaking enzymes would be too big to reach the links that must be cut in collagen fibrils, and prefer small molecules. Other people think that small molecules would not be specific enough for the task, what do you think? What is your prefered strategy?

David Spiegel: That's another excellent question. I think that as a small molecule chemist, I would love nothing more than to develop a small molecule that could break glucosepane cross-links, and it is certainly something we've been thinking about for quite some time. I think it is actually a very difficult challenge for a small molecule to break a stable cross-link like glucosepane. Mechanistically speaking, in terms of the underlying chemistry, I think it's not clear how a small molecule would function. Now, on the enzyme side, or I should say on the protein side, I think it's possible to imagine low molecular weight enzymes that could be tissue-permeable to the extent that they actually do reach glucosepane cross-links. So my preferred strategy is a protein agent, but by all means I encourage anyone out there listening, and I'm also encouraging people in my own lab group, that small molecule strategies should not be abandoned. I think that both strategies are viable, but the one I see succeeding on the shortest time frame is probably an enzyme.

Justin Loew: Other work in your lab has revolved around using synthetic molecules to detect cancer, and encourage the immune system to attack. Do you think antibodies could be brought to bear against glucosepane?

David Spiegel: Absolutely, and I should say our lab is in the process, and we're making great strides towards identifying the first selective anti-glucosepane antibodies with just that goal in mind. One can imagine an antibody that can bind to glucosepane, and have attached to it some kind of catalyst that would enhance the breakdown of glucosepane. One could also imagine an antibody that is useful for the diagnosis, the detection of glucosepane cross-links in tissue, and so I think that antibody strategies are really high on the list.

Justin Loew: A lot people who would like to help out in this type of research but don't have the expertise use crowdsourced computing efforts such as folding@home. Could the search for a glucosepane breaker be helped by this type of work?

David Spiegel: Absolutely, and in fact we've certainly discussed those efforts. We have collaborators who have started work along those lines for computationally modelling the role of glucosepane in collagen cross-links, and with that information in hand, it really could be possible to develop a kind of hypothetical mechanistic strategy. When I say mechanistic I mean how would a molecule work, what would the chemistry have to look like for an antibody, a small molecule, some other kind of therapeutic modality, to break down glucosepane. It does have a very unique and suprisingly stable chemical structure. In fact, breaking down glucosepane is more than just causing it to degrade. One would also need to cleave the molecule in such a way as to separate the lysine and arginine strands that are being cross-linked by glucosepane, such as to restore the mobility and flexibility in the tissues that are being cross-linked.

Justin Loew: Then for the do-it-yourselfers who might be into synthetic chemistry, or for the other labs who might be listening in, is the molecule you synthesized patented? Is your university licensing the process or the molecule?

David Spiegel: Yes, so it is patented. We are in discussions surrounding licensing the molecule. We are also providing the molecule to the community for basically the cost it takes for us to make it. We want to encourage efforts of all kinds to find glucosepane breakers, so making it commercially available and developing collaborations with other laboratories are all very high on our priority list. For the do-it-yourselfers out there who are interested, feel free to contact me, and we can certainly make an arrangement where our lab will provide glucosepane for research purposes.

Justin Loew: They should just look online for the Spiegel Research Group at Yale University, and they'll be able to contact you or a member of your lab?

David Spiegel: Correct.

Justin Loew: Great! And lastly here, what other research is underway in your lab currently, something people should be keeping an eye out for?

David Spiegel: We have a number of research programs devoted to aging and age-related cross-links. I should also point out that we have been very grateful to the SENS Research Foundation for funding our work - Aubrey de Grey, William Bains, Michael Kope, and others at the organization have just been incredible in terms of the vision for funding this. This is fairly high risk research. We have antibodies, we are developing reagents for detecting a wide variety of advanced glycation end-products, all of which we believe are involved in the aging process. We also have a major effort, and as I mentioned before, in the development of new immunotherapies. So we're using small molecules that we designed to seek out various kinds disease-causing cells, organisms, proteins, for detection by the immune system. So we can actually make molecules that can alert the immune system to the presence of disease-causing factors that the immune system might have missed. So there is obvious therapeutic potential there, not only in aging, but also in cancer, infectious disease, autoimmune disease, and a whole range of other conditions as well.

Justin Loew: Well, that does sound very promising. We'll all look forward to future research publications from your lab. Dr. Spiegel, thank you for joining me.

David Spiegel: Thank you! Great to be a guest.

Justin Loew: It is refreshing to hear of the collaboration between SENS and the Spiegel research group. It seems that SENS has achieved good results from this investment. The problem is that the money is running out. Dr. Spiegel informed me that funding at his university is drying up, and Aubrey de Grey mentioned the same thing late last year in regard to SENS. This means that your support for rejuvenation research is even more crucial this year, as the world economy slows down. As a non-profit that advocates for life extension and provides funding for small-scale research, Longecity has the power to help out. Please consider joining us as a member, and watch for Longecity-approved fundraisers through 2016. Until next time.

As ever, progress in the field of rejuvenation research is constrained far more by lack of funding than by the difficulty of the challenges involved. The challenge in bootstrapping a movement is always the leap from funding source to funding source, the need to raise enough to get things done, and then build on that progress to attract the next source of revenue. Collectively we have achieved great success in the past fifteen years, going from no investment in SENS to tens of millions devoted to this field. That, of course, is just a set up for the latest leaps in search of more funding, enough to carry out the work that remains to be done. It is amazing the degree to which persuasion is required to get people to help in saving their own lives in the future, but that is the nature of the world we live in.

Cancer Found in Naked Mole-Rats

Naked mole-rats are very long-lived in comparison to near relative species, and have a great resistance to cancer - to the point at which researchers have not characterized and reported on any incidence of cancer in their laboratory colonies, now numbering thousands of individuals, and not for lack of searching. This is a far cry from similarly-sized rodent species, all of which have a very high rate of cancer. There has been considerable interest in the research community in recent years in identifying the underlying mechanisms of cancer resistance in naked mole-rats, with an eye to seeing whether or not they can form the basis for human therapies or enhancements.

Here researchers finally manage to find unambiguous incidence of cancer in naked mole-rats, which will hopefully go some way towards better understanding the mechanisms involved in the suppression of cancer in this species. Reading between the lines, I suspect that these researchers think that cancer incidence in naked mole-rats is very low but not as low as is presently implied in the literature, and there is perhaps a lack of rigor in this area of reporting. In any case, "highly resistant" is not the same thing as "immune":

In recent years, the use of naked mole-rats (NMRs) as animal models in aging and cancer research has increased as a result of their demonstrated extreme longevity and apparent resistance to cancer. We previously surveyed spontaneous histologic lesions in a zoo-housed NMR colony over a 10-year period, which revealed several age-related diseases and uncommon pre-cancerous lesions, consistent with their reported cancer resistance. However, overt cancer has not been formally documented in NMRs from either zoos or biomedical research facilities. Herein, we describe cancer in 2 NMRs and relate this to our previous findings of proliferative and pre-cancerous lesions found in additional zoo-housed NMRs with a brief discussion of diagnostic criteria of rodent neoplasia in a laboratory setting.

In Case No. 1, we observed a subcutaneous mass in the axillary region of a 22-year-old male NMR, with histologic, immunohistochemical (pancytokeratin positive, rare p63 immunolabeling, and smooth muscle actin negative), and ultrastructural characteristics of an adenocarcinoma possibly of mammary or salivary origin. In Case No. 2, we observed a densely cellular, poorly demarcated gastric mass of polygonal cells arranged in nests with positive immunolabeling for synaptophysin and chromogranin indicative of a neuroendocrine carcinoma in an approximately 20-year-old male NMR. We also include a brief discussion of other proliferative growths and pre-cancerous lesions diagnosed in a zoo colony. Although these case reports do not alter the longstanding observation of cancer resistance, they do raise questions about the scope of cancer resistance and the interpretation of biomedical studies in this model. These reports also highlight the benefit of long-term disease investigations in zoo-housed populations to better understand naturally occurring disease processes in species used as models in biomedical research.


A Stem Cell Treatment for Optic Neuritis

Some classes of first generation stem cell transplants are known to reduce inflammation, though the signaling mechanisms involved are still poorly understood. Nonetheless, this means that a range of conditions thought to have a strong inflammatory component to their pathology are potential targets for treatment. Here for example, a clinician has found that stem cell transplants produce benefits in some patients suffering from the blindness produced by optic neuritis, chronic inflammation of the optic nerve that can occur for reasons that are unclear in many cases:

Vanna Belton was in Washington in 2009 when, while stuck in traffic one day, she noticed the streetlights were blurry. Weeks later she had almost no vision and no explanation for why everything seemingly went dark. She was diagnosed with a sudden and perplexing case of optic neuritis, a general term meaning optic nerve inflammation. As Belton searched for alternatives, she found Dr. Jeffrey N. Weiss, who was enrolling blind patients in an unorthodox stem cell study. He wasn't affiliated with a university or government institute, but he was taking on all those who could afford the roughly $20,000 to pay for the study and injecting stems cells into their eyes in one of three ways -- around the retina, in the retina and directly into the optic nerve -- in hopes of restoring some people's sight. He made no promises.

In early 2014, she had the surgery. During the four-hour procedure, Weiss and a medical team extracted bone marrow from Belton's hip, separated her stem cells in a machine and then injected the cells in and around her right eye's retina and directly into her left eye's optic nerve. Weiss is not following the usual steps of clinical studies. Among other things, he didn't test his treatment theories first on lab animals or using computer models, or randomize his trials by using either stem cells or placebos in study participants. He didn't test the procedure for safety on a small group before moving to a larger trial. Weiss, who is board-certified in ophthalmology, said he didn't have the patience for academic research, which is strictly governed by internal review boards and requires fundraising. Without a long history of stem cell research and a current academic appointment, he said, he sought legitimacy for his work by registering the trial with NIH, which scientific journals require to publish promising results.

The NIH also requires researchers to gain approval and oversight from an ethics review panel. Universities and government agencies have their own panels; Weiss tapped the International Cellular Medicine Society, an independent group that promotes stem cell therapies. Weiss said that 60 percent of his 278 patients with macular degeneration, glaucoma and other diseases have regained some sight. While he can't explain how it works, he believes that will become clear eventually. "We didn't know how penicillin worked for many years, but it saved many lives in the meantime. It is hubris to think that something can't work until you understand how it does. ... It is more important what the patient sees, not what I see." Sitting on the front steps of her home a year and a half ago, Vanna Belton was startled and thrilled when her eyes focused on a car's license plate. Essentially blind for more than five years, she could read the numbers and letters. No one disputes that Belton now sees well enough to, for example, read the menus in a restaurant. She can navigate the streets without the white cane she once used.


Engineering Arteries in Hours Rather than Weeks

Today I'll point out a good example of a new and improved methodology in tissue engineering: model arteries created in hours rather than the previous standard of weeks. There is a lot going in in this field, and the ability to create tissues from the starting point of cells and raw biomaterials is improving in leaps and bounds from year to year. From the point of view of speeding up research, many of the most important advances in the life sciences relate to logistics, and thus go largely unheralded because they have no direct connection to clinical translation of research into therapies. Yet any new technique that dramatically reduces time or cost in materials means that all of the research groups using it can get more done at a given level of funding. Moreover, reductions in cost usually also mean that researchers who were previously stuck on the sidelines can now get involved, adding their efforts to moving the state of the art that much faster. At the large scale, and over the long term, science is built on a foundation of ever-better infrastructure, not leaps of ideation.

At the present time a lot of the most important advances in tissue engineering are logistical, somewhat distant from clinical applications. The first engineered tissues very similar to those in living individuals are not destined for therapies, but rather to be used to speed up testing and research. Living tissue sections can replace a lot of the use of animal models, and at a much lower cost. At some stages small amounts of engineered human tissue can be far better tools for research than animal models, especially where tissue can be produced from the cells of patients with specific diseases or genetic conditions.

Another reason for this focus on small tissue sections for research is that generating blood vessel networks sufficient to support larger solid tissue masses, such as whole organs, is not yet a robustly solved problem. Researchers are definitely making progress, especially with the use of bioprinters capable of generating scaffolds incorporating small-scale structures, but the practical upper size limit on engineered tissue is still too small to be building organs in their entirety. This is one of the reasons why a great deal of effort is going into decellulization as a transitional technology, the use of donor organs cleared of cells to create a scaffold with blood vessels already in place that can be repopulated with a recipient's cells.

Looking at the results linked below, I think you'll agree that this is an impressive piece of work, though still removed a way from the desired end goals of firstly producing patient-matched replacement blood vessels to order for transplantation, and secondly finding a way to create blood vessel networks to order inside engineered tissue as it grows.

Rapidly Building Arteries that Produce Biochemical Signals

Arterial walls have multiple layers of cells, including the endothelium and media. The endothelium is the innermost lining of all blood vessels that interacts with circulating blood. The media is made mostly of smooth muscle cells that help control the flow and pressure of the blood within. These two layers communicate through a suite of chemical signals that control how the vascular system reacts to stimuli such as drugs and exercise. In a new study, biomedical engineers successfully engineered artificial arteries containing both layers and demonstrated their ability to communicate and function normally. The blood vessels are also miniaturized to enable 3D microscale artificial organ platforms to test drugs for efficacy and side effects. The new technique may also enable researchers to conduct experiments on arterial replacements in record time.

"We wanted to focus on arteries because that's where most of the damage is caused in coronary diseases. Most previous studies had focused on the media cells but hadn't spent much time on the endothelial cells, and nobody had shown how the two would interact. Many of the techniques for creating artificial tissue also were rather lengthy, which was frustrating." The frustration came from the six-to-eight weeks it took to grow arteries in the laboratory. Turning to the literature, researchers found a paper detailing a much faster technique used to create a trachea. The method works by putting cells of the desired tissue inside collagen and compressing for a few minutes. This both squeezes out excess water and increases the mechanical strength of the resulting tissue. For the next six months, researchers worked to convert the technique so they could create arteries. And not just any arteries - arteries scaled down to one tenth the size of a typical human's, which made the translation even trickier. "With a smaller diameter, we could make a lot of these artificial vessels in a short amount of time. We can make these vessels and use them in only a few hours. To me that was the biggest advance, because spending several weeks on each set was driving me crazy. While our arteries are small and intended for testing, they're just as mechanically strong as those intended to be put inside of the body. So the technique could be beneficial to researchers trying to create artificial arteries to replace damaged ones in patients as well."

Human Vascular Microphysiological System for in vitro Drug Screening

In vitro human tissue engineered human blood vessels (TEBV) that exhibit vasoactivity can be used to test human toxicity of pharmaceutical drug candidates prior to pre-clinical animal studies. TEBVs were made by embedding human neonatal dermal fibroblasts (hNDFs) or human bone marrow-derived mesenchymal stem cells (hMSCs) in dense collagen gel. The TEBVs developed in this study had several novel features. They could be prepared with inner diameters of 500-800 μm and perfused in less than three hours. In contrast, other approaches to prepare TEBVs require 6-8 weeks in vitro culture before the mechanical strength is sufficient to enable perfusion.

After 1 week of perfusion, medial hNDFs or hMSCs expressed contractile proteins α-smooth muscle actin and calponin, indicating a switch to a contractile phenotype. TEBVs also produced the extracellular matrix proteins laminin, collagen IV, and fibronectin and exhibited burst pressures similar to human saphenous veins. Quantifiable and physiologically relevant reactions to vasoactive stimuli occurred after only 1 week. TEBVs released nitric oxide, elicited endothelium-independent vasoconstriction to phenylephrine and endothelium-dependent vasodilation in response to acetylcholine, and maintained these responses during 5 weeks of in vitro perfusion culture.

Older Measures of Age via DNA Methylation Correlate with Increased Risk of Cancer

Patterns of DNA methylation, a type of epigenetic marker that regulates protein production, have been shown to change with age in fairly well defined ways. This provides the basis for a biomarker of aging, a way to quickly measure how physically aged an individual is, meaning how much age-related cell and tissue damage he or she has accumulated in comparison to peers of the same chronological age. A part of the process of validating this approach to measuring biological rather than chronological age is to compare age-related disease incidence over time in people with higher and lower measures of biological age:

Epigenetic age is a new way to measure your biological age. When your biological (epigenetic) age is older than your chronological age, you are at increased risk for getting and dying of cancer, reports a new study. And the bigger the difference between the two ages, the higher your risk of dying of cancer. "This could become a new early warning sign of cancer. The discrepancy between the two ages appears to be a promising tool that could be used to develop an early detection blood test for cancer. People who are healthy have a very small difference between their epigenetic/biological age and chronological age. People who develop cancer have a large difference and people who die from cancer have a difference even larger than that. Our evidence showed a clear trend."

A person's epigenetic age is calculated based on an algorithm measuring 71 blood DNA methylation markers that could be modified by a person's environment, including environmental chemicals, obesity, exercise and diet. This test is not commercially available but is currently being studied by academic researchers. In DNA methylation, a cluster of molecules attaches to a gene and makes the gene more or less receptive to biochemical signals from the body. The gene itself - your DNA code - does not change. This is the first study to link the discrepancy between epigenetic age and chronological age with both cancer development and cancer death using multiple blood samples collected over time. The multiple samples, which showed changing epigenetic age, allowed for more precise measurements of epigenetic age and its relationship to cancer risk. Other studies have looked at blood samples collected only at a single time point.

The study was a longitudinal design with multiple blood samples collected from 1999 to 2013. Scientists used 834 blood samples collected from 442 participants who were free of cancer at the time of the blood draw. For each one-year increase in the discrepancy between chronological and epigenetic ages, there was a 6 percent increased risk of getting cancer within three years and a 17 percent increased risk of cancer death within five years. Those who will develop cancer have an epigenetic age about six months older than their chronological age; those who will die of cancer are about 2.2 years older, the study found.


DNA Methylation Changes with Aging in Younger Individuals

The measurement of changing patterns of DNA methylation is developing into a promising biomarker of aging. The study linked below provides confirming evidence to show that this approach works for a wide range of ages in humans, but can still be discerning over a fairly narrow age range, even at younger ages, those at which people are likely to first start using future rejuvenation treatments. DNA methylation is a form of epigenetic marker that alters protein production: decorations attached to DNA that change constantly in response to circumstances. Some of those circumstances involve the accumulating cell and tissue damage that causes aging, processes that are the same in every individual, and so we should expect to find characteristic changes in DNA methylation patterns that reflect the state of aging.

Biomarkers of aging of this sort are important as an independent measure of the degree to which a putative rejuvenation therapy is actually working, a test that can be carried out much more rapidly and cheaply than the only currently viable approach of life span studies. By "actually working" I mean not just clearing senescent cells, or breaking cross-links, or replacing stem cells, all of which are simple enough to verify in and of themselves given the technology to build the treatment in the first place, but that a successful implementation of such as therapy also has an impact on global measures that are (a) strongly associated with aging, and (b) sensitive enough to pick up a change in biological age corresponding to a few years of normal aging.

Chronological aging-associated changes in the human DNA methylome have been studied by multiple epigenome-wide association studies (EWASs). Certain CpG sites have been identified as aging-associated in multiple studies, and the majority of the sites identified in various studies show common features regarding location and direction of the methylation change. However, as a whole, the sets of aging-associated CpGs identified in different studies, even with similar tissues and age ranges, show only limited overlap. In this study, we further explore and characterize CpG sites that show close relationship between their DNA methylation level and chronological age during adulthood and which bear the relationship regardless of blood cell type heterogeneity.

In this study, with a multivariable regression model adjusted for cell type heterogeneity, we identified 1202 aging-associated CpG sites in whole blood in a population with an especially narrow age range (40 - 49 years). Repeatedly reported CpGs located in genes ELOVL2, FHL2, PENK and KLF14 were also identified. Regions with aging-associated hypermethylation were enriched regarding several gene ontology (GO) terms (especially in the cluster of developmental processes), whereas hypomethylated sites showed no enrichment. The genes with higher numbers of CpG hits were more often hypermethylated with advancing age. The comparison analysis revealed that of the 1202 CpGs identified in the present study, 987 were identified as differentially methylated also between nonagenarians and young adults in a previous study (the Vitality 90+ study), and importantly, the directions of changes were identical in the previous and in the present study.

Here we report that aging-associated DNA methylation changes can be identified in a middle-aged population with a narrow age range of 9 years. A great majority of these sites have been previously reported as aging-associated in a population aged 19 to 90 years. Aging-associated DNA methylation changes are not uniform, but occur due to different reasons, at different rates and directions in different parts of the genome and are not alike in all cell types. Thus, due to this diverse nature of aging-associated DNA methylation changes, all confounding factors should be accounted for in the analysis, in order to obtain comparable results. Our results support the notion that cell type heterogeneity should be adjusted for when analyzing tissues consisting of mixed cell types. Moreover, our results imply that considerable proportion of DNA methylation changes show clock-like behavior throughout adulthood.


Oregon Cryonics, a New US Cryonics Provider

Cryonics is the low-temperature preservation of the recently deceased, with the aim of preserving the fine structure of the brain, and thus the data of the mind, for a future in which advanced technology will allow for a return to active life. The odds of success are unknown, but certainly infinitely greater than the zero odds offered by all of the present alternatives. Billions will die from old age before the earliest possible date on which the first complete set of robust rejuvenation therapies will become widespread. Are we really to write them off? I would like to think that we can do better than that - and hence the one viable chance offered by cryonics.

The non-profit cryonics industry, as opposed to the hobbyist endeavors that immediately preceded it, has existed for more than 40 years. Yet it has struggled to grow; over that time, only a few hundred people at most have been preserved. Only in recent years has the subject been treated with greater respect by the media and public, and bridges built with the cryobiology research community, who have long treated cryonics as an assault upon the integrity of their field. Now that reversible vitrification of organs is clearly plausible, and numerous groups are working towards that goal to improve the logistics of organ donation, transplantation, and tissue engineering, it is no longer possible to abitrarily declare that preserving the brain through the same methods is somehow fringe and outlandish.

Still, there are very few cryonics providers in the world, and only one outside the US, although this tiny, still largely non-profit industry also includes a surrounding halo of service and research companies such as Suspended Animation and 21st Century Medicine. These are as much involved in working towards the use of cryonics technologies in other areas of medicine as they are in improving the methodologies used to preserve patients at the end of life. The actual cryonics providers are simply listed: the long-standing US duopoly of the Alcor Life Extension Foundation and Cryonics Institute, and comparatively recent addition of KrioRus in Russia.

Given this, it is encouraging to see that a new group is launching another small US cryonics provider capable of long-term cryopreservation: Oregon Cryonics based in Salem. Their intent is clearly to compete on price with the established US non-profits, as their materials focus on preservation of the brain alone at a comparatively low price point. Assuming they have the technical resources to back up their efforts, and it is always important to carry out due diligence when paying for these sorts of services, then this strikes me as a positive evolution in the industry. More well-founded efforts, and a greater diversity of focus in those efforts, is very welcome. It is a little early for any meaningful public discussion in the cryonics community on the recent press for Oregon Cryonics, and the evolving contents of their web site, but it should be interesting to see what is thought of this approach.

As is usually the case, note that the local press coverage is terrible on the science and specific details. In particular, it is important to note that people are not frozen when cryopreserved, they are vitrified. There is a very big difference between these two things. After 40 years of practice, the operations and methodologies involved in carrying out a cryopreservation have become quite refined. It is also interesting to note that the Oregon Cryonics founder is another individual in the industry who favors the end goal of scanning and emulation of the mind in software rather than restoration of the original tissue, which will always seem to me to be a matter of engineering self-defeat at the final hurdle. A copy is not the self, and survival means survival of the specific package of matter that expresses the self, which means the brain must be restored.

Oregon Cryonics: 'The ultimate lottery ticket'

A Salem non-profit, Oregon Cryonics, is one of only four facilities around the world. The Salem location is run by Dr. Jordan Sparks. Cryonics is considered controversial, but Sparks says the hope is there. He envisions a future human or digital self in the next hundred years. "We can see a clear pathway from here to how somebody might be revived. If we don't do preservation, there's zero chance for survival," says Sparks. "We have electron micro-graphs showing good structured preservation and scientists around the world are currently mapping out neuroconnectors." He knows people are skeptical. "For some it's radical but so were the Wright brothers hanging out in the garage trying to invent flight. So until it happens, until people see it demonstrated, then it probably will remain controversial."

Frozen in time: Oregon firm preservex brains in hopes that science catches up

Until recently, there were only two cryonics facilities in the country freezing people or their brains, the Cryonics Institute in Detroit and Alcor Life Extension in Scottsdale, Ariz. Oregon Cryonics has signed up 10 clients to have either their bodies or their brains preserved and frozen after they die. Its operating model also has promised no small bit of controversy. The industry appears to be gradually gaining adherents, especially among young men who embrace technology. Sparks is a successful dentist and entrepreneur who says his startup is filling an industry niche -- lower-cost cryo for people willing to have just their brains preserved. He's banking on technology -- the idea that brain scanning will someday become sophisticated enough to map an entire brain and all its neural circuits. Then the brains that have been cryopreserved can be thawed, mapped and digitally downloaded. The people who once lived with those brains might live again, as software.

Phaedra and Aschwin de Wolf have opened a Northeast Portland lab called Advanced Neural Biosciences. There, among other things, they research the best methods for delivering cryoprotectant chemicals prior to freezing. Before moving to Portland, de Wolf worked for a Florida firm called Suspended Animation that provides services to cryonics companies. De Wolf also has signed up for full-body cryopreservation. He guesses that in 75 years technology will have reached a point where he can be brought back, with techniques to repair molecular damage that took place while he was frozen.

Fledgling Oregon Cryonics in Salem would seem to be a natural choice for the eventual preservation of Phaedra and de Wolf, since every minute counts in preserving the body after death if cellular decay is to be minimized. But both say they currently are committed to being preserved at Alcor in Arizona, and leaving open the possibility of switching over to Oregon Cryonics at some point. Both say they are concerned with the less than state-of-the-art preservation methods Oregon Cryonics has been willing to employ. In addition, de Wolf points out that in the past, cryo labs have shut down their operations and abandoned clients who were in cryo storage. The lesson there, de Wolf says, is that cryonics labs need to be well-established and accept only clients who can fully fund their treatment and preservation up front. "Some people say something is better than nothing, but I think that's not a good principle for cryonics," de Wolf says.

De Wolf's is not an uncommon position to take. Young companies are inherently risky, and in the case of cryonics the risk isn't just that you have to switch to use another product, but that you may indeed wind up in the grave and oblivion if the company goes out of business and can't negotiate a rescue with the rest of the industry. This is a challenge, but it is a challenge that every new entry in the field of medical services has to deal with. The way forward is to offer robust, reliable products and services, and to make use of independent certification agencies who can verify the claims made by the company and so offer customers peace of mind and assurance.

Links Between Mammalian Hibernation and Longevity

In this open access paper, researchers review what is known of the commonalities between the biochemistry of hibernation and variations in longevity between mammalian species:

Many mammals employ strategies of metabolic rate depression - entry into winter hibernation, summer aestivation, or daily torpor - to allow them to extend their survival chances under extreme environmental conditions. Hibernation is perhaps the best known phenomenon and has been observed in eight different groups of mammal. Prior to hibernation, metabolic re-programming is initiated that includes hyperphagia in the late summer /early autumn, which results in massive weight gain due to increased fat storage in white adipose tissue. Animals then typically go through a number of "test drop" events of short torpor bouts at reduced body temperatures that appear to induce metabolic re-programming. Subsequently animals can initiate prolonged periods of torpor (days to weeks) with up to 95-99% reduction of basal metabolic rate as compared to the nonhibernating state, body temperatures that can fall to near 0°C, and metabolism switched over to a main reliance on lipid as the primary metabolic fuel for all organs. In addition to regulating metabolic fuel storage to support hypometabolism, hibernators are also faced with increased cellular stress during their torpor bouts. The decrease in respiration and heart rate during torpor creates an environment that is vulnerable to hypoxia/ischemia damage, whereas animals are also susceptible to oxidative stress during interbout arousals when metabolic rate and oxygen consumption increases massively to rewarm the animal back to euthermic conditions. As such, hibernators are incredible models to study the mammalian metabolic plasticity and stress resistance.

While metabolic rate depression and stress resistance have been shown to be the fundamental mechanisms that are required to support hibernation, they are also two of the most common cellular processes that have been shown to directly influence aging. While research in the aging field to date has utilized impressive genetic models that have uncovered many fundamental mechanisms that regulate aging and longevity in a conserved manner, research in non-traditional models such as hibernators can provide new insights into how environmentally-induced metabolic adaptations could influence aging and longevity. Hibernators may provide an advantage over traditional aging models as they naturally induce a hypometabolic state that triggers regulatory responses in a number of cellular signaling pathways which produce a significant increase in maximum lifespan when genetically altered.

Understanding the mechanisms of the hibernation response is important from a comparative point of view, since the molecular mechanisms that regulate torpor-mediated metabolic depression are likely conserved across other similar adaptive stress responses such as anoxia and hypoxia tolerance. However, the uniqueness of hibernation as an adaptation in mammals provides potential applications for biomedicine. In addition to its potential importance in aging and longevity, hibernators are great research models for (1) natural organ preservation, as they experience minimal tissue damage while maintained at body temperature just above freezing, and (2) insulin resistance, as they undergo reversible periods of insulin resistance and obesity without the detrimental effects seen in diabetic patients.


An Example of the Present State of Tissue Printing

Researchers here demonstrate the ability to print simpler tissues such as muscle and bone, using a novel approach to somewhat increase the size of the tissue that can be constructed and transplanted. Size is limited by the need to supply oxygen and nutrients to cells via a blood vessel network, and reliably producing that blood vessel network in printed tissue is still an open problem:

Scientists have printed ear, bone and muscle structures. When implanted in animals, the structures matured into functional tissue and developed a system of blood vessels. Most importantly, these early results indicate that the structures have the right size, strength and function for use in humans. "This novel tissue and organ printer is an important advance in our quest to make replacement tissue for patients. It can fabricate stable, human-scale tissue of any shape. With further development, this technology could potentially be used to print living tissue and organ structures for surgical implantation."

The system deposits both bio-degradable, plastic-like materials to form the tissue "shape" and water-based gels that contain the cells. In addition, a strong, temporary outer structure is formed. The printing process does not harm the cells. A major challenge of tissue engineering is ensuring that implanted structures live long enough to integrate with the body. The scientists addressed this in two ways. They optimized the water-based "ink" that holds the cells so that it promotes cell health and growth and they printed a lattice of micro-channels throughout the structures. These channels allow nutrients and oxygen from the body to diffuse into the structures and keep them live while they develop a system of blood vessels.

It has been previously shown that tissue structures without ready-made blood vessels must be smaller than 200 microns (0.007 inches) for cells to survive. In these studies, a baby-sized ear structure (1.5 inches) survived and showed signs of vascularization at one and two months after implantation. "Our results indicate that the bio-ink combination we used, combined with the micro-channels, provides the right environment to keep the cells alive and to support cell and tissue growth." Another advantage of the system is its ability to use data from CT and MRI scans to "tailor-make" tissue for patients. For a patient missing an ear, for example, the system could print a matching structure.


Fight Aging! Invests in Oisin Biotechnologies

As I mentioned in yesterday's interview with Gary Hudson of Oisin Biotechnologies, I'm pleased to be able to say that Fight Aging! participated in the recent funding round for this senescent cell clearance startup. It was an unexpected opportunity to support this important line of SENS rejuvenation research, and will be my principle material contribution to the cause this year. From the point of view of where the money goes, there is actually little to no difference between investing in an early stage startup and making charitable donations to a laboratory group. In both cases the money buys research: lab time, reagents, mice, and the efforts of scientists. There is no rule that says a particular study has to be carried out before or after the point at which non-profit labwork transitions to for-profit labwork; where the work happens in the typical chronology of clinical translation is very much a matter of circumstance and the character of those involved. The closer things come to a working prototype, the more likely that someone will launch a company.

I consider it to be just as important to support the development of nascent SENS companies in their early stages as it is to fund the foundational work required prior to the point at which founding a startup becomes practical. An important part of the future of the rejuvenation biotechnology field is to create a virtuous cycle in which which an ecosystem of growing companies feeds new funding back into fundamental research. The ideal situation for such a company is the one for Oisin Biotechnologies, in which the people and organizations with the largest ownership stakes and the earliest investment are all SENS insiders who are going to pour any realized gains back into research in one way or another. As for all startups in biotechnology, these are long bets, and there must be many of them in order to catch the few that spark into lasting flame. Most will fail, leaving only their research results, and the ones that succeed may take five years or so to get to the point at which funds can meaningfully flow back to research.

Ah, but ... all it takes is one SENS startup to do well enough, and, provided it is run by the right people, it will sweep up and carry forward all of the rest of the SENS agenda. One thing to remember about SENS rejuvenation biotechnology is that it is very cheap in comparison to, say, traditional drug development. At this point finishing the SENS agenda to produce first generation therapies in mice capable of repairing all of the primary forms of cell and tissue damage that cause aging, say half a billion to a billion at this point, is much less than the cost of developing a single small molecule drug in the big pharma world, say two billion or so. A startup company in this field that made the transition to look something like a mid-sized pharmaceutical entity, with a market capitalization of billions, could probably finish up prototyping SENS on its own over a decade. It wouldn't be on its own, of course. If nothing else, the current clinical development of senescent cell clearance therapies, coupled with lifespan studies in mice, is going to wake up the world on the topic of rejuvenation. That is another good reason to support Oisin Biotechnologies.

At this point let me take a brief diversion into the evils of the US Securities and Exchange Commission (SEC). How is it that I knew about and had the chance to invest in Oisin Biotechnology and you didn't? Simply because I'm close enough to being an insider in this community to get an invite. The rules put in place on early stage investment essentially act to forbid what is called general solicitation: an early stage startup company can't simply advertise for investors. The founders can't reach out to the community at large. Raising a round cannot be public. The only only people normally allowed to invest in startups are those in the upper 5-10% of income or net worth, and the exceptions to that rule needed for seed and friends and family rounds, consisting of people of modest means like myself, to exist at all again require refraining from general solicitation. This is a great example of regulatory capture at work. The rules, ostensibly to protect people from themselves, as heaven forbid anyone actually be trusted to make their own assessments of risk in this world, are absolutely and definitely shaped over the years for far less altruistic reasons. The goal is to restrict the opportunity to invest in high-risk, high-reward early stage companies to established networks of professionals, to build barriers and keep out anyone not on the inside.

This is changing, however. The advent of Kickstarter and its competitors has meant that suddenly a whole range of companies could bypass the whole idea of early stage investment in favor of mass preordering as a source of early funding. That works really well for manufacturing and creative efforts with a fairly short time frame. It is obviously much less useful for biotechnology and medical development. The SEC, for reasons that may have to do with the basic bureaucratic urge to control everything, or the interest of various parties in building new opportunities for regulatory capture, has altered their rules on early stage funding to permit general solicitation in a crowdfunding like manner. Though of course, this being the SEC, it is legalistic, top-heavy, and people are still quite restricted in what they can invest. However, the basic point is that the investment process can be open and public, and in such a case anyone can invest. The new rules go into effect in the middle of 2016, and it remains to be seen how much of a mess or an opportunity it will be.

Mess or not, there is the potential to do something with this in our community. We are, modesty aside, pretty good at putting together and supporting modestly sized fundraisers for SENS research. If we can raise a quarter of a million in charitable donations for research, as happened last year, then I don't see it as beyond the pale that we could raise that much to crowdfund the founding of a future rejuvenation biotechnology company. Perhaps a glucosepane clearance venture, when that research gets to the point of a drug candidate, for example. Will this or something similar come to pass? Perhaps. It is at least possible, and as I pointed out above the funds still go to carrying out research. It is all a question of where that research is in the line of development from first spark through to clinical prototype.

So to finish up, what does this all mean for SENS charitable fundraising this year? Well, 2016 certainly promises to be as active as 2015 based on what I know is coming up already. The Major Mouse Testing Program will be running a crowdfunding effort in the months ahead, and I think at least one other SENS-relevant group may do the same. When it comes to this year's main SENS fundraising in the last quarter of the year, however, I can't lead in the same way as I've done in past years by putting money on the table and telling the world to match it - what might have been those funds went to Oisin Biotechnology and senescent cell research this year, an opportunity I could scarce turn down. Nonetheless, I believe we have plenty of time left in which to organize something interesting and useful, and I will still be the cheerleader to match the SENS Research Foundation's leadership when it comes to running the fundraiser. But let me put it to this audience: here is a bit of a gap, and all assistance in filling it will be greatly appreciated.

A Look at the Laron Syndrome Population

Laron syndrome is a form of dwarfism that occurs in a small human population all descended from a single mutant ancestor. It is of interest to aging researchers because the mutation is on the growth hormone receptor, analogous to that approach used to engineer the present record holder for mouse longevity, the growth hormone receptor knockout (GHRKO) lineage. These dwarf mice live 60-70% longer than their peers. However, as is the case for the differences in the long-term outcome of calorie restriction between mice and humans, there is no sign that Laron syndrome produces any meaningful lengthening of life. Human longevity has evolved to be much less plastic than that of short-lived mammals in response to circumstances and changes - such as those involving growth hormone - that affect insulin metabolism, and Laron syndrome is one of the illustrations of that point.

In the remote villages of Ecuador, 100 very small people may hold the key to a huge medical breakthrough. They all suffer from Laron Syndrome, an incredibly rare genetic disorder that stops them from growing taller than 4 feet but also seems to protect them against cancer and diabetes and maybe even heart disease and Alzheimer's. "There's only one patient that has died of cancer among all of the subjects. And that is fascinating," said Dr. Jaime Guevara-Aguirre, who has been studying the Laron population for 30 years.

The project has two goals: figuring out how to distill the anti-disease properties of Laron Syndrome into a medication that could be used to fight cancer, diabetes and other illnesses in the rest of the world, and getting treatment that could help young people with the syndrome grow to full size. "The complaint of these little people was, 'We're doing so much for you. What are science and the pharmaceutical companies, etc., doing for us?'" said Dr. Valter Longo, a longevity specialist.

Laron Syndrome was first identified in 1950 and there are only 350 people with it in the world, all descended from a single ancestor who introduced the mutated gene thousands of years ago. A third of them live in isolated communities in Ecuador, while others live in Spain. Unlike others with dwarfism, Laron patients don't lack growth hormone, but they have a defect in the receptor in the liver that is supposed to bind to the hormone and produce a substance called insulin-like growth factor 1. In Laron, there is no binding and no IGF-1 - and stunted growth as a result. But the absence of IGF-1 may also prevent the uncontrolled growth of cells that turn into cancer, and it creates extra sensitivity to insulin that serves as a shield against diabetes.

Longo duplicated Laron in lab rats. "The mice actually lived 50 percent longer and get a lot less diseases. It's very clear in the mice. Can it be true for people?'" His lab is testing drugs that would block IGF-1 in people, but the question is whether medicine will work as well as an actual mutation in humans. Longo said it will be at least a decade before they know the answer. Meanwhile, his team is also investigating its theory that Laron may be a defense against heart disease and Alzheimer's. Preliminary results show that at the very least, the little people don't have any higher risk of those conditions. The researchers say Laron patients tend to live just as long as their average-sized siblings.


Anti-Myostatin Antibody Treatment Increases Muscle Mass and Strength in Mice

As an alternative to myostatin gene therapy, treatments that temporarily block the action of myostatin have potential as a therapy to build muscle mass and strength. This is of particular interest as a way to compensate for sarcopenia, the characteristic loss of muscle that accompanies aging, and the approach is already in human trials. It is quite likely that such alternatives to gene therapy will reach the clinic first in more regulated regions, if only because they are favored by researchers and regulators for translation of genetic studies into the clinic. There is a tendency to researchers to look for approaches that require ongoing treatment to maintain, a tendency for pharmaceutical companies to want treatments that require ongoing expenditure rather than a one-time payment, and a tendency for regulators to endlessly delay anything related to gene therapy. Given the relentless advance of CRISPR, however, reducing costs and spreading the capability for gene therapy to many new labs and clinics, this will be happening at the very same time that gene therapies are available via medical tourism, I'll wager.

Sarcopenia, or aging-associated muscle atrophy, increases the risk of falls and fractures and is associated with metabolic disease. Because skeletal muscle is a major contributor to glucose handling after a meal, sarcopenia has significant effects on whole-body glucose metabolism. Despite the high prevalence and potentially devastating consequences of sarcopenia, no effective therapies are available.

Here, we show that treatment of young and old mice with an anti-myostatin antibody (ATA 842) for 4 weeks increased muscle mass and muscle strength in both groups. Furthermore, ATA 842 treatment also increased insulin-stimulated whole body glucose metabolism in old mice, which could be attributed to increased insulin-stimulated skeletal muscle glucose uptake as measured by a hyperinsulinemic-euglycemic clamp. Taken together, these studies provide support for pharmacological inhibition of myostatin as a potential therapeutic approach for age-related sarcopenia and metabolic disease.


An Interview with Gary Hudson of Oisin Biotechnologies, Senescent Cell Clearance Startup

As an approach to treating aging, senescent cell clearance has come of age. Rapid progress in a number of strategies has taken place in the past couple of years, UNITY Biotechnology made their big splash announcement of intent a few weeks ago, and life extension has been robustly demonstrated in mice through the removal of senescent cells. It is a great time for SENS, the Strategies for Engineered Negligible Senescence, as this one important strand of rejuvenation research - supported and advocated for more than a decade - is now energetically moving into clinical development. This pulls in previously unavailable funding from the venture community and at the same time expands public awareness of the plausibility of treating aging as a medical condition.

Today's topic is another young senescent cell clearance company that I've been enthused about since early last year: the company is Oisin Biotechnologies, founded and initially self-funded by Gary Hudson and Matthew Scholz. The Oisin researchers have what is arguably the best of current approaches to senescent cell removal and are to my eyes closer to implementation in humans than is UNITY. The early Oisin prototype work was known to the SENS Research Foundation folk soon after they started - this is a small community - but the path to getting the company seed funding in 2014 from first the Methuselah Foundation and then a few months later by the SENS Research Foundation was driven by David Gobel of the Methuselah Foundation. That funding paid for a successful proof of concept demonstration in mice, and earlier this year a new round of fundraising took place to set in motion the next stage of clinical development. I'm pleased to say that Fight Aging! participated in that round, a small helping hand for this important development project. More on that tomorrow, but for now let me turn you over to Gary Hudson of Oisin Biotechnologies to explain how they are approaching the challenge of senescent cell clearance to produce a rejuvenation therapy:

Who is Oisin Biotechnologies, how did you meet and decide that this was going to be your next venture?

Oisin was founded by two individuals, Matthew Scholz, who came up with the basic scientific approach for our first technology, and myself, who provided the initial angel funds along with the Methuselah Foundation and later, the SENS Research Foundation. I'm serving as Acting CEO while the company is in virtual mode.

Matt and I met a few years ago at one of the Bay Area Health Extension Salon evening programs (created by Joe Betts-Lacroix of Mousera). Interestingly, the primary speaker that evening was an old friend of mine, Judy Campisi of the Buck Institute. Matthew was a kick-off speaker introducing his then-new gene therapy company Immusoft. Judy was talking about exciting work that had just been published out of the Mayo Clinic that showed profound benefits of removing senescent cells in transgenic mice. Coincidentally, a follow up to this original work just published in Nature last week showing that clearing senescent cells could substantially extend life in naturally aged mice.

After the talks, Matthew and I were musing about potential ways to kill senescent cells that could be viable in humans. (By this time Matthew had spent a great deal of time researching vectors for gene therapy and was working with a non-viral suicide gene developed at Baylor and already used in humans). Matthew said he thought we could use a particular liposomal vector he'd come across in the past with the suicide gene to kill senescent cells in humans. He said he was too busy with and committed to Immusoft to take on another project, and it was so different from Immusoft's technology that it would likely be a detrimental distraction to their work if he tried to pursue it there. But the more we talked about it, the more compelling it sounded. Finally, I just said, "This has to happen. If you write this up, I'll fund it myself. I'll be the CEO and raise the rest of the money we need to see if it works." So, we licensed the liposomal vector, filed the first patent and built our prototype.

You are clearing senescent cells; what is the approach you are using, and how far along is it?

Our approach is quite different from most other attempts to clear these cells. We have two components to our potential therapy. First, there is a gene sequence consisting of a promoter that is active in the cells we want to kill and a suicide gene that encodes a protein that triggers apoptosis. This gene sequence can be simple, like the one in the Baker paper that kills p16-expressing cells, or more complicated, for example, incorporating logic to make it more cell type specific. The second component is a unique liposomal vector that is capable of transporting our gene sequence into virtually any cell in the body. This vector is unique in that it both very efficient, and appears to be very safe even at extremely high doses.

There's a subtle but profound distinction between our approach and others. The targeting of the cells is done with the gene sequence, not the vector. The liposomal vector doesn't have any preference for senescent cells. It delivers the gene sequence to healthy and senescent cells. We don't target based on surface markers or other external phenotypic features. As Matthew likes to say "we kill cells based on what they are thinking, not based on surface markers." So if the promoter used in our gene sequence (say, p16) is active in any given cell at the time of treatment, the next part of our gene sequence - the suicide gene - will be transcribed and drive the cell to apoptosis. However, if p16 isn't active in a given cell, then nothing happens, and shortly afterwards the gene sequence we delivered would simply be degraded by the body. This behavior allows our therapy to be highly specific and importantly, transient. Since we don't use a virus to deliver our gene sequence, and our liposomal vector isn't immunogenic, our hope is that we should be able to use it multiple times in the same patient.

So far we have demonstrated that our vector and gene sequence can efficiently and selectively kill senescent human cells in culture, and that we can target senescent cells in vivo in mice treated with chemotherapy. The next step is to show that our approach can achieve senescent cell clearance along the lines of the work done at the Mayo Clinic, but in a translatable model - without the use of their transgenic INK-ATTAC mice. After all, we aren't transgenic mice. As exciting as their work is, the data in those papers is purely an academic exercise; the treatment they gave the mice would be of limited value in humans. Our hope is that we will have our first data from our next studies this year.

How does your approach differ from that of UNITY Biotechnology?

I don't have any first-hand knowledge of the activities underway at UNITY; you and I have probably read the same coverage of their efforts. It appears that they are focused primarily developing small molecule drugs to kill senescent cells. As I was describing earlier, we are taking a transient gene therapy approach. Put another - less conventional - way, we're effectively killing senescent cells with a genetic computer program that we upload with our liposomal vector.

The beauty of our approach compared against a small molecule is that, if we want or need to, we can very rapidly tailor our treatment to kill a specific kind of cell under a specific circumstance, or tailor it to avoid a specific kind of cell - all by just changing the gene sequence we deliver. What we really have is a platform that allows us to selectively kill cells based on very specific and customizable genetic criteria. That kind of flexibility just isn't possible with a small molecule drug.

You just raised a funding round, what is the plan for the next year or so?

As I mentioned, all of the elements of our approach are working well, so now it is time to combine the pieces and do the work required to turn a promising candidate into a life-changing therapeutic. We hope to conduct several in vivo studies in the near future to assess the impact of the treatment on senescence induced by various means. If time and money permit, we'll also begin to try to understand what dose ranges are optimal, how many treatments might be required to dramatically diminish senescent cell body burden, and so on. We'd also like to set up for a large lifespan study in mice and maybe other animals as well. We'll be looking to make alliances with pharma partners that are focused on particular FDA indications, such as COPD, BPH, and so on.

What is your take on the bigger picture of SENS and the goal of ending aging?

I've been interested in this topic since I was a teenager, right at the time we were doing real moonshots (not the Google equivalent). When people asked me what I wanted to do with my life, I routinely and only half jokingly replied - "fly to the stars and live forever" - borrowing a theme from the science-fiction writer James Blish. But I found that it was hopeless to expect progress on the aging front in 1969, so I turned my attention to space, and became one of the first commercial space entrepreneurs. After 45 years in that "space" I'm now ready to spend some time focusing on engineering a solution to the problems of aging.

I was also the first major contributor to the SENS project. I helped fund the first SENS conferences and also the Methuselah Mouse Prize. I believe in the basic SENS notion of treating aging as an engineering problem - repair, replace, and restore function and you will both increase healthspan and move towards escape velocity.

What do you see as the best approach to getting nascent SENS technologies like this one out into the clinic?

This is a complex question. Personally, I'm not too interested in the normal "pharma" path to the clinic. That's not to say that we (or more likely some future pharma partners) won't pursue this route, but the costs have to be weighed against the need to move therapies into public view, soon. So it's necessary to examine alternative routes to the clinic. One area that is slightly orthogonal to the traditional path is to work on veterinary and companion animal treatments before a human product. Working out our strategy is a significant part of my near-term job, with the other focus being the next major raise of dollars in our Series A, sometime in 2016.

If this works stupendously well and everyone involved becomes wealthy, what next?

Essentially all of my ownership stake in Oisin will go into my nonprofit (to be announced shortly) and will be used to advance cutting edge translational medicine. But while I hope we make a profit for our investors' sake, my ambition in helping found Oisin has been to move the needle on true anti-senescence therapies. If we're successful, yes, we have a good chance to make money. But money is only important to me in that it'd allow us to move quickly onto the next aging-related problem, and that's what we'll do.

To the degree that Oisin succeeds, that success will channel funds into the Methuselah Foundation and SENS Research Foundation, as well as to a number of individuals who are already strong supporters of the longevity science cause. These are people who, like myself, are well aware that the only rational use for excess money is to fund the development of radical life extension technologies. What use is wealth to the sick and the dead? The true power of wealth in our day and age is that it can now be spent to build the technologies needed to defeat aging and illness. If only it was the case that more people realized this, we might be so much further ahead.

We Create Technology to Remove Suffering and Death

Right from the outset, the spur for the creation of new technology was the desire to reduce the personal impact of suffering and death. In this I agree with author Stephen Cave that to a large degree the rise to civilization was driven by the day to day minutiae of the quest for immortality: don't starve, don't be cold, don't get injured, don't be conquered, cure sickness, heal wounds, preserve life and health in the moment so as to see another dawn. We're still building the medical aspects of that edifice one small brick at a time, most of the way through dealing with infectious disease, and now turning our view to aging. The agents of technological progress, the researchers and the developers, gnaw away at each of the myriad individual causes of pain and mortality, one at a time, sometimes getting rid of them entirely (smallpox, insufficient food production), sometimes merely reducing them a little (heart disease, cancer). The next group picks up the banner, and continues to try to further erode that cause of mortality and sickness.

Progress is accelerating. We can envisage numerous paths ahead that might lead to a defeat of degenerative aging before the end of this century. We may well begin the replacement of our evolved biology with much more efficient and resilient designed machinery, such as artificial immune systems and oxygen transport nanomachines. We may augment ourselves with new tissues, perhaps genetically improved, such as additional thymus organoids or extensions to the kidneys and liver. Alternatively we may remain in our present human form for a long time, and simply repair the damage that causes aging. All of these will be spurred by the desire to remove first mortality, then pain, and finally - when nothing else is left - inconvenience and frustrated desire. There is a hierarchy of needs, and we will follow it.

If death is inevitable, then all we can do is die and hope for the best. But perhaps we don't have to die. Many respectable scientists now believe that humans can overcome death and achieve immortality through the use of future technologies. But how will we do this? The first way we might achieve physical immortality is by conquering our biological limitations - we age, become diseased, and suffer trauma. Aging research, while woefully underfunded, has yielded positive results. In addition to biological strategies for eliminating death, there are a number of technological scenarios for immortality which utilize advanced brain scanning techniques, artificial intelligence, and robotics.

But why conquer death? Why is death bad? It is bad because it ends something which at its best is beautiful; bad because it puts an end to all our projects; bad because all the knowledge and wisdom of a person is lost at death; bad because of the harm it does to the living; bad because it causes people to be unconcerned about the future beyond their short lifespan; bad because it renders fully meaningful lives impossible; and bad because we know that if we had the choice, and if our lives were going well, we would choose to live on. That death is generally bad - especially for the physically, morally, and intellectually vigorous - is nearly self-evident.

Yes there are indeed fates worse than death and in some circumstances death may be welcomed. Nevertheless for most of us most of the time, death is one of the worst fates that can befall us. That is why we think that suicide and murder and starvation are tragic. That is why we cry at the funerals of those we love. Our lives are not our own if they can be taken from us without our consent. We are not truly free unless death is optional.


The Slow Upward Trend in Life Expectancy at 65 Continues

Remaining life expectancy for older people, such as at 65, has been increasing slowly for a long time. The smoothed rate is in the vicinity of one year of additional life expectancy gained for every passing decade, though as recent data shows the year to year changes in the statistical measure of life expectancy are more variable. This upward trend is most likely the result of some combination of increased wealth, which allows for greater use of medical technology among other things, and improvements in the quality of medical technology to treat age-related disease. Therapies and outcomes for heart disease have improved greatly over the past twenty years, for example.

It is still the case that all of this additional life is something of an incidental side-effect, however: the clinical community isn't yet deliberately targeting and treating the forms of cell and tissue damage that cause aging. Treatments are instead patching the consequences. While the patches are getting better, for so long as they fail to address the root causes of disease and degeneration, the benefits will always be limited. When efforts to repair the damage that causes aging start in earnest, when for example it is possible for the average person to buy a senescent cell clearance therapy a few years from now, then expect to see the life expectancy trend to leap upwards in comparison to the past.

Over the last 30 years there has been an upward trend in life expectancy at older ages in England. However, male life expectancy was lower in 2012 than 2011 at ages 85 and 95, and at ages 65 and 75 it was the same in both years. There were no further falls in 2013, and this flattening of the recent trend has not continued in 2014, which saw a rise in life expectancy once again.

For those aged 65, men can expect to live for another 19 years and women a further 21 years. Life expectancy among older age groups in England rose to its highest level in 2014 - with male life expectancy increasing by 0.3 years at age 65 and 0.2 years at ages 75, 85 and 95 since 2013. Female life expectancy increased by the same amounts at the same ages. In the past, statistics have tended to focus on life expectancy at birth but now that most deaths in England occur in people over the age of 80, patterns of mortality in older age groups are becoming more important.

In the EU as a whole there has been an overall upward trend in life expectancy at older ages. The charts show an upward trend for male and female life expectancy at ages 65, 75 and 85 for the EU as a whole and its largest countries, including the UK. There was a dip in life expectancy in 2012 for the EU and many of the largest EU countries. In the EU as a whole, male life expectancy at age 85 fell by 0.1 years between 2011 and 2012, and female life expectancy at age 85 fell by 0.2 years. In contrast, between 2012 and 2013, almost all countries in the EU had an increase in life expectancy. While some countries had particularly large increases in life expectancy at older ages between 2012 and 2013, the increases for the UK were small in comparison. The rise in the UK was smaller than the EU average rise in every age group except males aged 85, was smaller than similar sized countries such as France and Spain, but was greater than Germany.


Alcor Position Statement on Aldehyde-Stabilized Cryopreservation

Cryonics provider Alcor have today published their position on aldehyde-stabilized cryopreservation. This is the vitrification methodology used by 21st Century Medicine to win the first stage of the Brain Preservation Prize earlier this month. The researchers demonstrated exceptional preservation of fine structure in mammalian brains, which by the present consensus in neurobiology is a compelling argument that the data of the mind encoded in that structure is also preserved. This in turn lends weight of validation to the existing methods of vitrification used by the cryonics industry, and can be placed alongside last year's results showing preservation of memory in vitrified and restored nematode worms.

It is worth noting that end goals are not aligned among advocates for cryopreservation and other forms of tissue preservation that can in principle maintain the data of the mind. This is important because end goals steer today's decisions on research, development, and advocacy, such as the type of approach used to preserve brain tissue. There is a strong contingent, the Brain Preservation Foundation founders among their number, that sees cryopreservation as a step on the road towards mind uploading. Their expectation is that preserved minds will be scanned and run in emulation, the original cryopreserved brain discarded or destroyed in the process. From this viewpoint, tissue restoration isn't even a question, and it certainly isn't a goal to optimize for. All optimization of technique should go towards provable preservation.

Those of us who think that a copy is not the self, and that the original tissue must be restored in order for a preserved individual to actually survive, have different and arguably harder goals. Not only do we want provable preservation of neural structure but we also want to make life easier for those who will one day work to restore the archives of cryopreserved brains. In this I find myself on the fence; I'm not certain that the additional chemical entanglements of, for example, aldehyde fixation raise the bar that much in comparison to what we already know future restoration requires. Molecular nanotechnology, a full understanding of brain biochemistry, and absolute control over cellular biochemistry are the plausible requirements at the high level, and communities or entities capable of deploying that mix of capabilities shouldn't be much daunted by whatever we have done today, provided that we succeeded in preserving the structure and did not destroy the biological macromolecules involved.

Alcor Position Statement on Brain Preservation Foundation Prize

We are pleased that vitrification, the same basic approach that Alcor Life Extension Foundation has utilized since 2001, is finally being recognized by the scientific mainstream as able to eliminate ice damage in the brain. Alcor first published results showing this in 2004. The technology and solutions that Alcor uses for vitrification, a technology from mainstream organ banking research, were actually developed by the same company (21st Century Medicine) that developed Aldehyde-Stabilized Cryopreservation (ASC) and has now won the Brain Preservation Prize.

ASC under the name "fixation and vitrification" was first proposed for cryonics use in 1986. ASC enables excellent visualization of cellular structure - which was the objective that had to be met to win the prize - and shows that brains can be preserved well enough at low temperature for neural connectivity to be shown to be preserved. Vitrification without fixation leads to dehydration. Dehydration has effects on tissue contrast that make it difficult to see whether the connectome is preserved or not with electron microscopy. That does not mean that dehydration is especially damaging, nor that fixation with toxic aldehyde does less damage. In fact, the M22 vitrification solution used in current brain vitrification technology is believed to be relatively gentle to molecules because it preserves cell viability in other contexts, while still giving structural preservation that is impressive when it is possible to see it.

While ASC produces clearer images than current methods of vitrification without fixation, it does so at the expense of being toxic to the biological machinery of life by wreaking havoc on a molecular scale. Chemical fixation results in chemical changes (the same as embalming) that are extreme and difficult to evaluate in the absence of at least residual viability. Certainly, fixation is likely to be much harder to reverse so as to restore biological viability as compared to vitrification without fixation. Fixation is also known to increase freezing damage if cryoprotectant penetration is inadequate, further adding to the risk of using fixation under non-ideal conditions that are common in cryonics. Another reason for lack of interest in pursuing this approach is that it is a research dead end on the road to developing reversible tissue preservation in the nearer future.

Alcor looks forward to continued research in ASC and continued improvement in conventional vitrification technology to reduce cryoprotectant toxicity and tissue dehydration. We are especially interested in utilizing blood-brain barrier opening technology such as was used to win the prize, but which pre-dated work on ASC. For cryonics under ideal conditions, the damage that still requires future repair is now more subtle than freezing damage. That damage is believed to be chiefly cryoprotectant toxicity and associated tissue dehydration. Nonetheless this is a groundbreaking result that further strengthens the already strong case that medical biostasis now clearly warrants mainstream scientific discussion, evaluation, and focus.

The folk at Evidence Based Cryonics have also put out a statement, focused on the technical details as much as the significance:

Groundbreaking Scientific Results Prove that the Proposition of Human Medical Biostasis has Potential and Needs to Be Brought into Mainstream Scientific and Medical Focus

Recently we have seen scientific evidence that long-term memory is not modified by the process of whole organism cryopreservation through vitrification and revival in simple animal models (C. elegans nematode), supplementing knowledge that other small animals with nervous systems can also be healthily revived after storage in storage in liquid nitrogen at a temperature of -196C (O. jantseanus leech). Earlier we also knew that in mammalian hippocampal brain slices viability, ultrastructure, and the electrical responsiveness of the neurobiological molecular machinery that elicits long-term potentiation, a mechanism of memory, can be preserved without appreciable damage following cryopreservation. Published transmission and scanning electron microscopic images from a whole brain cryopreserved through vitrification and also indicate structural integrity.

And now, a new cryobiological and neurobiological technique, aldehyde-stabilized cryopreservation (ASC) provides a strong proof that brains can be preserved well enough at low temperature for neural connectivity (the connectome) to be completely visualized. The connectome is believed to be an important encoding mechanism for memory and personal identity (sense of self/where the mind lives) within the brain. This is a truly groundbreaking result and puts the proposition of human medical biostasis as a way to save humans who otherwise would die squarely within the realm of what may be possible.

Cytomegalovirus Presence Expands Considerably in Old Age

The open access paper referenced here expands the picture of cytomegalovirus and the aging immune system with additional data. Cytomegalovirus (CMV) is a common herpesvirus present in near everyone by the time old age rolls around. In the majority of people it presents no symptoms, but it is apparently an important factor in the age-related decline of the immune system. Like all herpesviruses it cannot be effectively cleared from the body, and over the years the immune system devotes ever more of its limited resources to uselessly fighting it. An old immune system contains legions focused on cytomegalovirus and all too few cells capable of responding to other pathogens. This is one of the contributing causes of immunosenescence, the progressive failure of the immune system with age.

The best approaches to solving this problem actually involve expanding the population of useful immune cells rather than getting rid of cytomegalovirus. Clearing it doesn't fix the damage done: the specialized cells are already specialized. So possible treatments might involve delivering infusions of immune cells grown from the patient's own stem cells, selectively destroying cytomegalovirus-targeted immune cells to free up space for replacement with new immune cells, or restoring the thymus to increase the pace at which new immune cells are created.

Cytomegalovirus infection has been associated with a variety of health problems in elderly people and there is increasing interest in the mechanisms that underlie this association. A key determinant in this regard will be greater understanding of the balance of the viral load and the host immune response during healthy ageing. In this study we report, for the first time, that the level of cytomegalovirus viral load within the blood increased markedly in elderly people. A novel feature of our work was the use of digital droplet PCR (ddPCR) to provide an accurate quantitative measure of latent viral DNA. Previous methods for detection of CMV generally relied on nested PCR techniques, which made quantification challenging and also raised substantial problems with reproducibility.

Our work was performed using DNA isolated from monocytes, which are established as the most important haemopoietic site of viral latency. The first interesting finding was the observation that CMV was detectable in only a minority of donors, as 64% of people remained negative by ddPCR despite the presence of chronic infection as confirmed by CMV-specific IgG positivity. Indeed, in younger people below the age of 50 years, the detection of CMV load in the blood was uncommon, being observed in only 13% of donors tested. The lower limit of detection provided by ddPCR in our assay was for a single copy of virus within the total reaction volume and as such a negative result indicated absent or extremely low levels of virus. This low level carriage may reflect a lower intrinsic probability of viral reactivation in younger donors but is perhaps more likely to reflect the consequence of effective immune surveillance of viral replication in younger individuals.

The frequency of viral detection increased markedly with each decade above the age of 50 years to 37.5% and 50% and finally became positive in every donor who was older than 70. Interestingly the amount of viral DNA detected within the blood also increased substantially with age with a 29 fold increase observed between donors aged less than 70 and those over this age. The use of nested PCR also detected viral DNA within the majority of healthy elderly donors. These data indicate that a gradual impairment in the ability to control CMV load within blood starts around the age of 50 years and then deteriorates markedly beyond the age of 70. In conclusion, these data reveal the delicate balance that has evolved between chronic CMV infection and the host immune response and indicate that this symbiosis can break down during ageing, where an increase in CMV viral load occurs as the attritional effects of chronic surveillance and the impact of immune senescence become more apparent. It is likely that increased understanding of the clinical importance of chronic viral infection on human health will become an important health consideration in future years.


Poor Fitness Correlates with Later Smaller Brain Volume

The results of this study can be added to the many reasons to keep up with a decent level of exercise. A sedentary lifestyle has costs, most of which manifest as a greater risk of age-related disease in later later:

Poor physical fitness in middle age may be linked to a smaller brain size 20 years later. "We found a direct correlation in our study between poor fitness and brain volume decades later, which indicates accelerated brain aging." For the study, 1,583 people enrolled in the Framingham Heart Study, with an average age of 40 and without dementia or heart disease, took a treadmill test. They took another one two decades later, along with MRI brain scans. The researchers also analyzed the results when they excluded participants who developed heart disease or started taking beta blockers to control blood pressure or heart problems; this group had 1,094 people.

Exercise capacity was estimated using the length of time participants were able to exercise on the treadmill before their heart rate reached a certain level. For every eight units lower a person performed on the treadmill test, their brain volume two decades later was smaller, equivalent to two years of accelerated brain aging. When the people with heart disease or those taking beta blockers were excluded, every eight units of lower physical performance was associated with reductions of brain volume equal to one year of accelerated brain aging. The study also showed that people whose blood pressure and heart rate went up at a higher rate during exercise also were more likely to have smaller brain volumes two decades later. People with poor physical fitness often have higher blood pressure and heart rate responses to low levels of exercise compared to people with better fitness.


Proposing a Microbial Cause of Alzheimer's Disease, Again

The biochemistry of the brain is enormously complex and still poorly understood at the detail level. This is also true of the mechanisms of Alzheimer's disease. Treating Alzheimer's is, more or less, the unified banner under which the research community raises funds to map and catalog the brain. It is why so much funding pours into the study of this one condition in comparison to others. In the research mainstream it is expected that only with much greater understanding of neurobiology will effective therapies emerge. Since the molecular biology involved is so very complicated, there are many gaps into which new theories of disease progression can fit without much challenge. Building theories is a lot easier and cheaper than running studies, and so there will always tend to be more theorizing than construction of potential therapies. This is especially true when, as is the case today, the dominant paradigm of amyloid clearance has yet to produce results despite years of trials. Perhaps that indicates it is harder than expected, or perhaps it indicates that it is a wrong direction.

Some of the more interesting alternative theories include the idea that amyloid clearance channels in tissues close to the brain fail with age for many of the same reasons that blood vessels accumulate damage in aging issues. This is a putative cause and possible fix for increasing amyloid levels. The Methuselah Foundation is funding a test of that theory, as such a test should be cheap and fairly conclusive one way or another.

Another set of theories argues that Alzheimer's has a meaningful microbial contribution to its development, that progression of the condition is sped up by exposure to fungal and other pathogens. In the paper here, this is presented as a new category of Alzheimer's disease rather than as a contributing factor to a single unified condition called Alzheimer's. I think it pretty likely that Alzheimer's will be formally split up into categories in the years ahead. Neurobiochemistry is a big enough space to fit numerous distinct paths leading to a similar end result in which aggregates like amyloid overrun the brain and harm its cells, and that seems a more likely reality than one path.

Inhalational Alzheimer's disease: An unrecognized - and treatable - epidemic

Identifying subtypes of Alzheimer's disease may aid in the development of therapeutics, and recently three different subtypes have been described: type 1 (inflammatory), type 2 (non-inflammatory or atrophic), and type 3 (cortical). Type 3 is very dissimilar to the other two types, and may be mediated by a fundamentally different pathophysiological process (although, by definition, still β-amyloid positive and phospho-tau positive): the onset is typically younger (late 40s to early 60s); ApoE genotype is usually 3/3 instead of 4/4 or 3/4; the family history is typically negative (or positive only at much greater age); symptom onset usually follows a period of great stress, sleep loss, anesthesia, or menopause/andropause; presentation is not predominantly amnestic but is instead cortical, with dyscalculia, aphasia, executive dysfunction, or other cortical deficits; and the neurological presentation is often preceded by, or accompanied by, depression.

Over the past two decades, elegant work has demonstrated unequivocally that biotoxins such as mycotoxins are associated with a broad range of symptoms, including cognitive decline. These researchers and clinicians identified a constellation of symptoms, signs, genetic predisposition, and laboratory abnormalities characteristic of patients exposed to, and sensitive to, these biotoxins. The resulting syndrome has been designated chronic inflammatory response syndrome (CIRS). The most common cause of CIRS is exposure to mycotoxins, typically associated with molds.

Our findings suggest that patients with presentations compatible with type 3 Alzheimer's disease should be evaluated for CIRS (as well as other toxic exposures, such as mercury and copper). These are treatable etiologic agents, and thus treatable causes of Alzheimer's disease. Furthermore, it may be particularly important to identify or exclude these toxins in patients with type 3 Alzheimer's disease since amyloid may be protective against toxins, especially metals, so reducing the amyloid burden without reducing the toxic exposure may potentially exacerbate the pathophysiology. Conversely, the exclusion of patients with type 3 Alzheimer's disease may potentially enhance the group efficacy of anti-amyloid therapies.

It is noteworthy that there has been direct detection of fungi in the brains of patients who had died with Alzheimer's disease, contrasting with a lack of detection of fungi in control brains. This finding raises the possibility that the mycotoxic effects that occur in CIRS associated with type 3 Alzheimer's disease may be accompanied by active infection. However, unlike in the case of CIRS, there is as yet no indication that treating the putative fungal infection has any ameliorative effect on the cognitive decline. The increasing number of reports of various pathogens identified in the brains of patients with Alzheimer's disease raises the possibility that what is referred to as Alzheimer's disease may actually be the result of a protective response to various brain perturbations. Thus amyloid may function as part of an inflammatory/antimicrobial response.

A Study Suggesting that Dementia Incidence is Declining

The research noted here stands in opposition to the present consensus on dementia, which is that incidence will increase as other age-related diseases are increasingly controlled. Many people avoid dementia because other conditions kill them first, particularly heart disease. If given additional years of life thanks to improved therapies, then some will later suffer dementia. However, it appears that the improvements in vascular health in old age that have reduced the impact of heart disease also have the effect of significantly reducing dementia incidence. A large fraction of the causes of dementia is a matter damage and dysfunction of the blood vessels in the brain, leading to slow, incremental structural damage to brain tissue.

Despite the concern of an explosion of dementia cases in an aging population over the next few decades, a new study, based on data from the Framingham Heart Study (FHS), suggests that the rate of new cases of dementia actually may be decreasing. It is believed that the number of Americans with Alzheimer's disease and other dementias will grow each year as the size and proportion of the U.S. population age 65 and older continues to increase. By 2025 the number of people age 65 and older with Alzheimer's disease is estimated to reach 7.1 million - a 40 percent increase from the 5.1 million aged 65 and older affected in 2015. By 2050, the number of people in this age population with Alzheimer's disease may nearly triple, from 5.1 million to a projected 13.8 million, barring the development of medical breakthroughs to prevent or cure the disease.

FHS participants have been continuously monitored for the occurrence of cognitive decline and dementia since 1975. Thanks to a rigorous collection of information, FHS researchers have been able to diagnose Alzheimer's disease and other dementias using a consistent set of criteria over the last three decades. Researchers looked at the rate of dementia at any given age and attempted to explain the reason for the decreasing risk of dementia over a period of almost 40 years by considering risk factors such as education, smoking, blood pressure and medical conditions including diabetes, high blood pressure or high cholesterol among many others.

Looking at four distinct periods in the late 1970s, late 1980s, 1990s and 2000s, the researchers found that there was a progressive decline in incidence of dementia at a given age, with an average reduction of 20 percent per decade since the 1970s, when data was first collected. The decline was more pronounced with a subtype of dementia caused by vascular diseases, such as stroke. There also was a decreasing impact of heart diseases, which suggests the importance of effective stroke treatment and prevention of heart disease. Interestingly, the decline in dementia incidence was observed only in persons with high school education and above.


Long-Term Benefits of Senolytic Drugs on Vascular Health

Senolytic treatments are those that at least partially clear senescent cells, producing a narrow form of rejuvenation, enhanced longevity, and improvement in long-term health. One of the fortuitous discoveries of recent years was that a combination of the drugs dasatinib and quercetin can clear enough senescent cells in a single treatment in mice to demonstrate that doing so is beneficial. The research noted here extends that result to investigate some of the outcomes of a series of treatments over time.

It is unfortunately unlikely that the same degree of clearance will happen in humans via the use of these particular drugs, but people are certainly going to try anyway. The real value of this research lies in the ability to prove that getting rid of these cells is robustly beneficial in mammals. This will result in increased support for the clinical development of methods that will work in humans. Some of those methods already exist in prototype form and work is presently underway on these approaches at Oisin Biotechnology and Unity Biotechnology, for example.

Cells become senescent in response to stress or damage, irreversibly removing themselves from the cycle of division and replication. This most likely initially serves to reduce risk of cancer by suppressing the ability of the most vulnerable cells to become cancerous, but as the number of senescent cells rises, they have a growing detrimental effect on tissue function. Senescent cells secrete signals that produce chronic inflammation, haphazardly remodel surrounding tissue structures, and encourage bad behavior in neighboring cells. In short, senescent cells are one of the causes of aging, and therapies under development to remove them are the first practical rejuvenation biotechnologies after the SENS model.

Building on previous studies, researchers have demonstrated significant health improvements in the vascular system of mice following repeated treatments to remove senescent cells. They say this is the first study to show that regular and continual clearance of senescent cells improves age-related vascular conditions - and that the method may be a viable approach to reduce cardiovascular disease and death. "Cardiovascular disease remains the leading cause of death in our population today, and disability related to heart disease and stroke has a tremendous impact on our aging population. This is the first evidence that longer term use of senolytic drugs to clear these damaged cells from the body can have a preventative impact against vascular diseases."

Senescent cells are damaged cells that no longer function properly, but remain in the body and contribute to frailty and many of the other health conditions associated with aging. Prior studies showed chronic removal of the cells from genetically-altered mice can alter or delay many of these conditions, and short-term treatment with drugs that remove senescent cells can improve the function of the endothelial cells that line the blood vessels. This study, however, looked at the structural and functional impacts of cell clearance using a unique combination of drugs on blood vessels over time. Mice were 24 months old when the drugs - a cocktail of dasatinib and quercetin - were administered orally over a three-month period following those initial two years. A separate set of mice with high cholesterol was allowed to develop atherosclerotic plaques for 4 months and were then treated with the drug cocktail for two months.

The research showed that senescent cell clearance in either naturally-aged or atherosclerotic mice alleviated vascular dysfunction. Although it did not reduce the size of plaques in mice with high cholesterol, it did reduce calcification of existing plaques on the interior of vessel walls. "Our finding that senolytic drugs can reduce cardiovascular calcification is very exciting, since blood vessels with calcified plaques are notoriously difficult to reduce in size, and patients with heart valve calcification currently do not have any treatment options other than surgery. While more research is needed, our findings are encouraging that one day removal of senescent cells in humans may be used as a complementary therapy along with traditional management of risk factors to reduce surgery, disability, or death resulting from cardiovascular disease."


Arguing that Progeria Mechanisms are Significant Enough in Normal Aging to Be Worth Addressing

Today I'll point out a very long post that argues we should pay more attention to the mechanisms of Hutchinson-Gilford progeria syndrome (HGPS, or simply progeria) in normal aging. Progeria is one of a small number of rare conditions in which patients have the appearance of accelerated aging. It isn't really accelerated aging, but it is at root a form of biological breakage that leads to greatly increased rates of cellular damage and dysfunction. This produces medical conditions that overlap with those of normal aging since they, also, are the consequence of high levels of cellular damage and dysfunction. Both aging and progeria result in cardiovascular disease and kidney failure, for example, but the root causes are very different. In the case of progeria damage results from a mutation in the lamin A gene, and as a consequence an encoded protein that is vital to cellular function has abnormal behavior. Among other issues observed in progeroid tissues, cell nuclei are misshapen and the ability for cells to replicate is consequently limited.

The cause of progeria was discovered not so long after the turn of the century, and researchers have since then made some inroads towards a treatment. The latest and most promising - and perhaps also the most surprising - is the use of methylene blue, one of the oldest of modern medical compounds. Along the way, evidence has accumulated for the basic mechanism of progeria, damaged lamin A, to be present to a small degree in normally aged tissues. It is far from clear that this has any meaningful impact in comparison to the other forms of cell and tissue damage that cause aging, and for my part I would be surprised to find that it rivals the others to a level that demands action now. This is still a scientific discussion in progress, however, and opinions can differ.

The post linked here is written from a programmed aging perspective, which I think tends to make people look for links that are not there. In search of a genetic program for degenerative aging, the author proposes that lamin A mutations can act as a trigger for that program, and therefore it is worth following the chain of cause and consequence to see what falls out of that investigation. In the alternative view of aging as the consequence of accumulated damage, there is no need for such work: damage causes dysfunction, and progeria is just a much more uniform source of fundamental cellular damage than is the normal aging process. Our level of concern with progeria should therefore match the degree that it contributes to normal aging, which is at present an open question with the presumption that the answer will probably be "not greatly."

Hutchinson-Gilford Progeria Syndrome - a disease of accelerated aging due to Alternative Splicing

HGPS has received attention because it so closely mimics the normal picture of aging. A main difference between normal aging and HGPS is that the entire "aging program" is completed in about 15 years with HGPS, whereas with normal aging, the "aging program" takes almost 100 years to complete. Whereas a few people with normal aging can live as long as 122 years, almost all of the people with HGPS die by 16-20 years of age. The most common findings in HGPS include features that mimic normal aging, such as alopecia, skin atrophy, mottled pigmentation of the skin, generalized lipodystrophy, joint stiffness, arthritis, arteriosclerosis, coronary artery disease, left ventricular enlargement, and strokes. However, HGPS children also have unique findings that do not "mimic" normal aging, such as absent eyebrows, prominent eyes/proptosis, micrognathia, open cranial bone fontanelles, and absent sexual maturation. This is why some have called HGPS a "caricature of normal aging", rather than a "copy of normal aging."

Until 2006, no one really thought that there was much true overlap between HGPS and normal aging. Even expert scientists studying the biology of aging did not think that progerin, the mutant form of prelamin A, accumulated in cells undergoing normal aging. No one says that today. Several independent research teams have published data between 2006 and 2013 which confirm that progerin accumulates in normal skin cells with aging and triggers the same cellular and molecular features of HGPS. Another recent study showed that cellular senescence induces progerin production, whereas immortalized cells suppressed progerin production. Further, progerin accumulates as a function of chronological aging in the blood vessel walls of normal individuals who do not have HGPS. Although the adventitia has the highest concentration of progerin, it also accumulates in the media and intima as well. Progerin accumulation in the walls of blood vessels only affects 1 out of every 1,000 cells at birth and increases at a rate of 3.34% per year. As the endothelial cells divide, they "pass on" the progerin to subsequent generations of daughter cells.

The first obvious lesson we can learn from HGPS is that "a single gene abnormality can trigger the entire aging program". This is not to say that aging is simply due to a cryptic space site mutation in the LMNA gene, but rather that one cryptic splice site can trigger all of aging. HGPS is not the only disease that can do this. Several other diseases due to single point mutations in completely different genes can do the same thing (Ex: DNA repair deficiencies such as Werner's syndrome). However none of these other mutations produce an "aging phenotype" at such a young age or that has such a close resemblance to normal aging. For instance, Werner's syndrome does produce an accelerated aging phenotype that looks like normal aging, but occurs later in life (This is why Werner's syndrome is often called "adult progeria").

Another important lesson we can learn from HGPS is that this disease shows that aging is more like a program which is accelerated from the normal 100 years (normal aging) to 15 years (HGPS). Nature has given us many examples of "molecular programs", such as gestation and embryogenesis. It is hard for most people to accept that aging is programmed too, but there is good evidence for this. The best line of evidence against a non-programmed type of aging is that 100% of humans develop the same set of features with aging in a similar order of events. If aging was truly a random, stochastic event, the features of aging would occur in random order and would not affect 100% of human beings (i.e. random events don't happen 100% of the time in the same order). The fact that over 80% of the features of normal aging are also seen in children with HGPS suggest that this disease is truly an accelerated aging model. The million dollar question, however, is can this aging program be reversed or slowed?

Needless to say I don't agree with any of the above thinking on programmed aging and the relevance of progeria in that light. The ordering argument doesn't seem a good one to me: people do develop age-related conditions in different orders, and the overall progression of aging is the gestalt of countless trillions of molecular events, meaning that randomness is smoothed over time. The author does present and comment on a great many papers on the molecular biochemistry of progeria and aging, and the post is well worth reading for that regardless of where you stand on aging as a process.

Tuning Macrophages in Cancer Immunotherapy

Immunotherapy is a broad category, and covers many very different strategies for tackling cancer and other conditions by engineering immune cells or adjusting the behavior of the immune system as a whole. In this case, researchers have found a novel and interesting approach:

Similar to stem cells differentiating to make your body's tissues, the immune system's macrophages pick a life path, differentiating into macrophages that recruit resources for wound repair or macrophages that recruit resources for wound sterilization. Cancers encourage macrophages to pick the path of wound-repair, making what are called "M2" or "repair-type" macrophages. Cancers use these M2 macrophages to promote their own growth. However, researchers can now successfully flip M2 macrophages into their wound-sterilizing cousins, called "M1" or "kill-type" macrophages, which, contrary to promoting the growth of new tissue, may aid the immune system in clearing the body of cancer.

Previous work has shown that people with a naturally high ratio of M1 to M2 macrophages are less prone to develop cancer. And in mouse models of the disease, encouraging a high M1-to-M2 ratio can "slow or stop cancer growth." In fact, there are two schools of thought describing how, exactly, to change a population of M2 macrophages into a population of M1 macrophages. In the first school of thought, M2 macrophages can reverse their differentiation to become briefly more "stem-like" before being encouraged to use their second chance to pick the more beneficial M1/kill-type phenotype. In the second school of thought, as macrophages naturally die out, they could be replaced by a new population dominated by M1 macrophages. The paper describes a way to accomplish the second: In the presence of the cytokine interferon gamma, macrophages take on the M1 phenotype.

"Interferon gamma has been explored as a possible therapeutic agent, but there are problems with it. Interferon gamma mediates hundreds of effects and some of them aren't very comfortable." Instead, one idea is to improve the sensitivity of cells to the interferon gamma that already exists in the body. "In the right context, macrophages lose their sensitivity to interferon gamma and we want to prevent that." Another approach seeks to augment interferon gamma only in tumor tissue, keeping its effects localized. "The immune system's killer cells produce interferon gamma and one promising strategy is to get them to the tumor and activated in the right way." In fact, existing immunotherapies seek to recruit the body's killer cells, especially cytotoxic T cells, to recognize and attack tumor tissue. A byproduct of this activation is the production of interferon gamma at the tumor site, which causes macrophages to take the M1 and not M2 phenotype. "Cytotoxic T cells can directly kill tumor cells. But they also produce interferon gamma. Both are likely contributing to the anti-tumor effect. By devising approaches to tune macrophages in the right way, we hope to further improve immunotherapies."


On Building Measures to Link Aging and Disease

In this popular science article on the relationship between aging and age-related disease, a researcher discusses one of a number of approaches to producing a biomarker of aging, a sensitive measure of the degree to which an individual is impacted by the cell and tissue damage of aging. A good biomarker should predict the onset of disease and remaining life expectancy to the degree that these are determined by damage:

In epidemiological studies, particular those focused on the molecular mechanisms of 'growing older', loss of function and the emergence of 'biomarkers' of disease, even in young middle-aged 'healthy' adults, are often presented as diagnostics for human ageing. From my perspective, this is almost certainly misleading as it implies that health, disease and longevity are all interchangeable synonyms for ageing. If we wish to identify a definitive 'ageing' molecular programme (e.g. biological age), one that is independently informative for future health and life span then it is critical that we clearly define what is meant by the term 'ageing' and appropriately develop an assay that measures this parameter. We also have to consider if the developed diagnostic, while statistically significantly related to biological age, is sufficiently sensitive and specific enough to be considered a useful diagnostic (most will fail this final criteria e.g. telomere assays).

The other major consideration relates to how a novel diagnostic of 'biological age' would be used. If it were to be used as an independent diagnostic of longevity then it would be combined with other factors and behaviours that determine life-span, such as smoking and obesity. One could imagine the generation of an integrated risk 'score' utilised to determine insurance premiums for healthcare or to calculate pension requirements. These may seem controversial examples, but in reality our chronological age (birth year) and behaviours are already judged and used for these purposes. Why not have a more accurate 'diagnosis' of the contribution 'age' makes to these decisions? For example, if you are a poor 'biological age' (for your chronological age) then your breast-cancer or prostate-cancer screening might be scheduled 5-10 yr earlier than average.

Variation in the human transcriptome (RNA) has proven particularly powerful for identifying the huge variations in human physiology and physiological responses to environmental influences. So it is not surprising it has been used to develop diagnostics of human ageing, including our own model. While you can't use chronological age to diagnose the health status of an individual - the relationship between chronological age and disease is an epidemiological one - existing RNA or DNA methylation assays represent composites of ageing, disease and drug-treatment and not chronological age. We believe that 'biological' age will determine when you show clinical symptoms of disease and that we need an assay which accurately reflects your underlying 'rate of ageing' or 'biological age'. Which 'age associated' disease an individual then develops will depend on their genetic, epigenetic and environmental risks factors (and stochasticity).

To produce this new diagnostic of 'biological age' we had the hypothesis that we can find a set of RNAs in the tissue that was diagnostic for telling tissue from healthy old from healthy young people apart. In our study healthy old people were living a normal sedentary lifestyle, did not have type II diabetes and importantly had good fitness levels. By applying machine learning to this 'special' healthy ageing cohort, we found 150 RNA markers. In fact we could see that these 150 RNAs were either up or down regulated in tissue from healthy old people and we reasoned that activation of this gene expression 'programme' may help explain why these 65 year old people achieved good health despite living a sedentary life style. In fact, when we then applied the 150 RNA assay to a group of 70 year old people (people with the same chronological age) we found that their 'biological age' score varied dramatically and for those that failed to switch the gene expression pattern "on" as much died sooner and had a greater decline in organ function (kidney).


21st Century Medicine Wins the Small Mammal Brain Preservation Prize

The folk at 21st Century Medicine have been working, largely unheralded, for years with the aim of improving the technologies used in cryopreservation of tissue. The goals are twofold: firstly to make cryonics a much more reliable and robust end of life choice, and secondly to introduce reversible organ vitrification into the tissue engineering and transplant industry. These go hand in hand, as if it is possible to store a kidney for years or decades and later transplant it, fully functional, into a patient, then it is also possible for the body and brain to be preserved at death rather than going to the grave and oblivion. This opens up the chance at a longer life in the future for those who will age to death too soon to benefit from the rejuvenation therapies presently under development.

Cryonics, like longevity science, is simultaneously one of the most neglected and important areas of science and development. So very many lives could be saved were there just a little more support for the growth of this industry. So I am pleased to see that the 21st Century Medicine researchers have won the Small Mammal Brain Preservation Prize offered by the Brain Preservation Foundation. They have demonstrated exceptional preservation of the fine structures of the brain that the present scientific consensus believes store the data of the mind. This is an important step forward for cryonics, being both the basis for a potentially better approach to cryopreservation, as well as solid support for the contention that cryopreservation of the brain preserves the mind. This is good, unequivocal evidence to add to that from last year's study demonstrating that memory survives vitrification in nematode worms.

Newly invented Aldehyde-Stabilized Cryopreservation procedure wins Brain Preservation Prize

The Small Mammal Brain Preservation Prize has officially been won by researchers at 21st Century Medicine. Using a combination of ultrafast chemical fixation and cryogenic storage, it is the first demonstration that near­ perfect, long­-term structural preservation of an intact mammalian brain is achievable. You can view images and videos demonstrating the quality of the preservation method for yourself at the evaluation page. This result directly answers what has been a main scientific criticism against cryonics, and sets the stage for renewed interest, research, and debate within the mainstream scientific and medical communities. "​Every neuron and synapse looks beautifully preserved across the entire brain. Simply amazing given that I held in my hand this very same brain when it was vitrified glassy solid... This is not your father's cryonics."

A team from 21st Century Medicine, spearheaded by recent MIT graduate Robert McIntyre, has discovered a way to preserve the delicate neural circuits of an intact rabbit brain for extremely long-­term storage using a combination of chemical fixation and cryogenic cooling. Proof of this accomplishment, and the full "Aldehyde ­Stabilized Cryopreservation" protocol, was recently published in the journal Cryobiology and has been independently verified by the Brain Preservation Foundation through extensive electron microscopic examination.

Throughout the contest, the 21CM team was in a tight race with Max Planck researcher Shawn Mikula to be the first to meet the prize's strict requirements. Although the prize will be awarded to 21CM, we wish to emphasize that a mouse brain entry submitted by Dr. Mikula also came extremely close to meeting the prize requirements. Dr. Mikula's laboratory is attempting to perfect not only brain preservation (using a different method based on chemical fixation and plastic embedding) but whole brain electron microscopic imaging as well. Focus now shifts to the final Large Mammal phase of the contest which requires an intact pig brain to be preserved with similar fidelity in a manner that could be directly adapted to terminal patients in a hospital setting. The 21st Century Medicine team has recently submitted to the BPF such a preserved pig brain for official evaluation. Lead researcher Robert McIntyre has started the company Nectome to further develop this method.

Aldehyde-stabilized cryopreservation

We describe here a new cryobiological and neurobiological technique, aldehyde-stabilized cryopreservation (ASC), which demonstrates the relevance and utility of advanced cryopreservation science for the neurobiological research community. ASC is a new brain-banking technique designed to facilitate neuroanatomic research such as connectomics research, and has the unique ability to combine stable long term ice-free sample storage with excellent anatomical resolution. To demonstrate the feasibility of ASC, we perfuse-fixed rabbit and pig brains with a glutaraldehyde-based fixative, then slowly perfused increasing concentrations of ethylene glycol over several hours in a manner similar to techniques used for whole organ cryopreservation. Once 65% w/v ethylene glycol was reached, we vitrified brains at -135C for indefinite long-term storage.

Vitrified brains were rewarmed and the cryoprotectant removed either by perfusion or gradual diffusion from brain slices. We evaluated ASC-processed brains by electron microscopy of multiple regions across the whole brain and by Focused Ion Beam Milling and Scanning Electron Microscopy (FIB-SEM) imaging of selected brain volumes. Preservation was uniformly excellent: processes were easily traceable and synapses were crisp in both species. Aldehyde-stabilized cryopreservation has many advantages over other brain-banking techniques: chemicals are delivered via perfusion, which enables easy scaling to brains of any size; vitrification ensures that the ultrastructure of the brain will not degrade even over very long storage times; and the cryoprotectant can be removed, yielding a perfusable aldehyde-preserved brain which is suitable for a wide variety of brain assays.

One interesting point worth noting is that many of the people involved in these efforts don't see restoration as the ultimate goal of cryonics. Rather they are in favor of scanning the structure of the brain, possibly destructively, followed by reconstruction of the mind in software in the form of a whole brain emulation of some sort. So to their eyes the complete goal here is fidelity of preservation, the quality of the vitrification of fine structures: everything else is a matter of scaling up the capabilities of scanning, software, and computational hardware, all of which look like foregone conclusions for the decades ahead at the moment. For those of us who think that a copy of the self is someone else, and for whom the self means the actual physical structure of the brain, there is the matter of how this preservation would be reversed in the future, however. It is very interesting - and encouraging - to watch progress towards reversible vitrification of organs for the transplant and tissue engineering industry, as that is where the still missing pieces of technology needed for the other side of cryonics will emerge.

In Search of the Genetics of Longevity in Sea Urchins

Comparative biology is an important tool in aging research, as the analysis of similar species with widely divergent life spans can in theory point out the more important mechanisms of aging. The more similar the species the better, and so here researchers investigate the genetics of two sea urchin species that exhibit a twenty-fold difference in life span. This is a preliminary set of data, absent any rigorous analysis, but even at the outset it doesn't exactly fit the expected picture. There is no real reason to expect a universality of relative importance of mechanisms across diverse species, so things that have proved to be important in well-studied species such as flies, mice, and people may well turn out to have little relevance to more distant branches of the tree of life. As a general rule, we should always expect biology to be more complex and varied rather than less so:

Sea urchins have attracted attention due to the extreme longevity of some of their species. Red sea urchin, S. franciscanus, populating cold waters of Pacific coast of North America, was demonstrated to survive over a century. Although S. franciscanus could not be cultivated in the lab for a century for direct observation, deposition pattern of radioactive carbon released to the Pacific upon nuclear tests and skeleton growth rate studies using tetracycline labeling allowed red sea urchin to climb the pedestal of the most long-lived marine animals. At the same time, green sea urchin, L. variegatus, populating warm Caribbean sea hardly survive over four years. Although direct difference in the senescence rates between red and green sea urchins is hard to demonstrate directly on the sole basis of field studies, these two related species might be the a convenient pair for comparative genetics of longevity. In this report we aimed to obtain draft genome assemblies of S. franciscanus and L. variegatus and compare the sequence of their proteins related to longevity with longevity related proteins of other species.

Analysis revealed several aminoacid positions that co-vary with longevity. Although this approach is not guaranteed from mistakes originated from misalignment, identification of related proteins that have different function, it could present a framework of further hypothesis-driven experiments on longevity. Our analysis revealed highly uneven distribution of proteins having aminoacid residues that co-vary with longevity among functional categories. Surprisingly, several categories of proteins were completely devoid of such positions. For example, nuclear encoded mitochondrial proteins and proteins involved in reactive oxygen species inactivation. Minimum of such aminoacids were found in the components of insulin/IGF1 pathway. Particularly enriched in positions that vary in coordination with longevity are categories of mitochondrial proteins encoded in mitochondrial genome, lipid transport proteins, proteins involved in amyloidogenesis and system of telomere maintenance. Among other, catalytic subunit of telomerase, telomerase reverse transcriptase (TERT) holds absolute record of the frequency of such positions. Despite the fact, that somatic telomerase activity could be detected in short and long living sea urchins, TERT might be involved in longevity due to more intricate mechanisms, such as maintaining the balance between support of tissue renovation and simultaneous restriction of unwanted proliferation of cancerous cells.


Protecting Osteoblasts to Enhance Bone Mass and Strength

Bone is constantly remodeled at the small scale, created by cells called osteoblasts and destroyed by cells called osteoclasts. One of the proximate causes of osteoporosis, age-related loss of bone mass and strength, is a growing imbalance between these two cell populations. Any of a range of approaches that can tilt the balance back towards osteoblasts and bone creation is likely to slow skeletal degeneration, and that is demonstrated in mice in the study linked here. As a matter of interest note that this particular approach is the exact opposite of that used in the first senolytic drugs: inhibiting cell self-destruction rather than encouraging it via the same target of Bcl2 proteins.

The Bcl2 family proteins, Bcl2 and BclXL, suppress apoptosis by preventing the release of caspase activators from mitochondria through the inhibition of Bax subfamily proteins. We reported that BCL2 overexpression in osteoblasts increased osteoblast proliferation, failed to reduce osteoblast apoptosis, inhibited osteoblast maturation, and reduced the number of osteocyte processes, leading to massive osteocyte death. We generated BCLXL transgenic mice using the same promoter in order to investigate BCLXL functions in bone development and maintenance.

Bone mineral density in the trabecular bone of femurs was increased, whereas that in the cortical bone was similar to that in wild-type mice. Osteocyte process formation was unaffected and bone structures were similar to those in wild-type mice. A micro-CT analysis showed that trabecular bone volume in femurs and vertebrae and the cortical thickness of femurs were increased. Analysis revealed that the mineralizing surface was larger in trabecular bone, while the bone formation rate was increased in cortical bone. The three-point bending test indicated that femurs were stronger in BCLXL transgenic mice than in wild-type mice.

The frequency of TUNEL-positive primary osteoblasts was lower in BCLXL transgenic mice than in wild-type mice during cultivation, and osteoblast differentiation was enhanced, but depended on cell density, indicating that enhanced differentiation was mainly due to reduced apoptosis. Increased trabecular and cortical bone volumes were maintained during aging in male and female mice. These results indicate that BCLXL overexpression in osteoblasts increased the trabecular and cortical bone volumes with normal structures and maintained them majorly by preventing osteoblast apoptosis, implicating BCLXL as a therapeutic target of osteoporosis.


Is the Present Human Life Span Enough?

Is the present human life span enough? This was the topic for a recent debate, wherein Aubrey de Grey of the SENS Research Foundation and Brian Kennedy of the Buck Institute were matched against Ian Ground of Newcastle University and Paul Root Wolpe of the Emory Center for Ethics. Obviously my answer to the question is a resounding no; we should absolutely be doing far more than we are to eliminate aging and extend healthy life spans to the greatest degree possible. I am in a minority for holding that view, however. A growing minority, but a minority nonetheless. Two thirds of the population, when asked, say that yes, the present length of life is just fine. For my money, I think this is simply that most people live in the moment, within the bounds of what is, and give little thought to what might be different. If the wall is white and has always been white, you'll only get blank stares if you ask people what color it should be. What is familiar is equated with what is best, or sufficient, or good. Most people see the future as more of the present, just a different day with different fashions. Managing to hold this state of mind whilst standing amidst the fastest pace of progress in history is a feat, but clearly we humans are up to it.

Perhaps the most interesting aspect of the position that present length of life is sufficient is that near all of the people who think this way, will if asked, also say that cancer, heart disease, Alzheimer's, and other well-known age-related conditions should be cured. This is inconsistent, to say the least, as these conditions are caused by aging. They, and the other failure modes of organs and tissues that have been given formal names, are what kill people. Aging is the wear and tear that gives rise to these conditions, but these are not separate things. The only way to prevent age-related disease is to control the processes of aging - such as through periodic repair of damage after the SENS model - so as to indefinitely sustain function and health. If function and health are sustained, then life is lengthened. It is impossible to decouple aging from health.

The next time you find someone who thinks that the present length of life is fine, ask them what disease they want to suffer and die from. What is an acceptable way to decay into death? Heart disease? Kidney failure? How about neurodegeneration, the loss of the mind? My guess is that they don't want to suffer any of the above, and have hazy notions of an easy death at the end of life. Modern societies have pushed the ugly realities of what it means to age to death out of mind, behind curtains and into nursing homes and hospitals. That ugly reality for near everyone is pain and degeneration, the loss of function over time, and a very unpleasant end. Again, the only way to prevent that is to control the underlying processes of damage that cause aging and disease, and by doing so extend health and life. There is no picking that apart. It is only through ignorance of how things actually work in our biology that people can hold the strange and inconsistent positions that they do on aging, medicine, and longevity.

Lifespans are Long Enough

What if we didn't have to grow old and die? The average American can expect to live for 78.8 years, an improvement over the days before clean water and vaccines, when life expectancy was closer to 50, but still not long enough for most of us. So researchers around the world have been working on arresting the process of aging through biotechnology and finding cures to diseases like Alzheimer's and cancer. What are the ethical and social consequences of radically increasing lifespans? Should we accept a "natural" end, or should we find a cure to aging?

Is 78.8 Years Long Enough to Live?

First to argue in favor of the motion that "Lifespans are long enough" was professor of bioethics and director of the Emory Center for Ethics, Paul Root Wolpe. He said: "We all want to live longer. Maybe even forever. But I think the quest for immortality is a narcissistic fantasy. It's about us. It's about me. It's not about what's good for society." As Wolpe saw it, the question is not about whether it's possible to extend life but whether it's desirable. He viewed making the pursuit of indefinitely long life a goal in and of itself as wrong-headed. "Will life extension make the world a better place, a kinder place? Has extended life expectancy made it better? I don't think so," Wolpe said.

First to debate against the motion that lifespans are long enough was Aubrey de Grey, chief science officer of SENS Research Foundation. "I believe that the defeat of aging is the most important challenge facing humanity," he declared. "I'm going to start with this question about the alleged conflict between individual desire and societal good." De Grey compared the issue to people not wanting themselves or anyone else to get Alzheimer's disease. "It's a societal good because we don't like each other to get sick any more than we want to get sick," he said. De Grey doesn't believe that future problems are anywhere near as horrifying as the problem we have today. He said: "Let me tell you exactly how bad the problem that we have today actually is. Worldwide roughly 150- to 160,000 people die each day. And more than two-thirds of those people die of aging. It's crazy. In the industrialized world, we're talking more like 90 percent of all deaths. Let's actually do something about it."

Philosopher Ian Ground of Newcastle University and Secretary of the British Wittgenstein Society supported the motion that lifespans are long enough. Ground questioned the wisdom of having an indefinitely long life that could be led with no thought about its ending or decline. He urged us to consider a decision like committing to a certain career, person or place. People can't do everything, marry everybody or live everywhere, Ground said. We become particular people by making those choices, and must recognize that with natural capacities come natural limitations, he added.

The final panelist, who argued against the motion "Lifespans Are Long Enough," was Brian Kennedy, CEO and president of the Buck Institute for Research on Aging. Kennedy addressed speculation from the previous three speakers about what life might be like if we lived to 150, from how society would change to the prospect of boredom. "Maybe we're going to be bored. Well, you know, if you ask me: 'Do I want to have cancer at 75? Do I want to have Alzheimer's disease at 85? Or do I want to be bored at 110?' I know which one I'm going to take," said Kennedy.

In the end, the team arguing against the motion "Lifespans Are Long Enough" won, according to the audience. The post-debate score results were 40 percent for the proposition, 49 percent against and 11 percent undecided.

Aging Hair Follicles Change to Become Skin

An interesting mechanism that appears to contribute to age-related hair loss was recently identified. It is unusual in that cells of one tissue structure are changing to cells of another as a result of age-related damage:

Scientists have uncovered a new mechanism behind hair loss: When stem cells in hair follicles are damaged by age, they turn themselves into skin. Over time, this happens to more and more stem cells, causing hair follicles to shrink and eventually disappear. This is the first time such a switch has been associated with aging in any tissue. Stem cells - precursor cells that can give rise to specialized cells like skin and hair - regenerate throughout the life of an organism and are located all over the body. But unlike stem cells in the blood or intestinal lining, hair follicle stem cells regenerate on a cyclical basis. Their active growth phase is followed by a dormant phase, in which they stop producing hair. These discrete on-off periods make hair follicle stem cells a useful model for studying stem cell regulation - and hair loss.

To figure out why hair thins in old age, researchers looked at hair follicle stem cell growth cycles in live animals - a daunting task - and found that age-related DNA damage triggers the destruction of a protein called Collagen 17A1. That in turn triggers the transformation of stem cells into epidermal keratinocytes. In their new state, the damaged stem cells slough off easily from the skin's surface. "When damaged cells deplete that niche of collagen 17A1, they alter their own signaling environment. It is interesting that these damaged cells change their fate rather than committing suicide through apoptosis (programmed cell death) or stopping cell division through senescence."

To see whether their results carried over to people, the researchers analyzed hair follicles in scalps from women aged 22 to 70. They found that follicles in people over 55 were smaller, with lower levels of Collagen 17A1. "We assume that ... aging processes and mechanisms similar to those in the mice explain the human age-associated hair thinning and hair loss." Stem cell depletion is unlikely to be the only factor behind the condition, however.


How Do Stem Cell Transplants Produce Heart Regeneration?

Stem cell transplants spur greater regeneration in an injured heart that would normally be the case, and so far it appears to be the case that this is a matter of signaling that changes the behavior of native cells rather than the transplanted stem cells integrating with native tissue and generating new cells. Past studies have shown that the stem cells don't last long following transplant. Nonetheless the beneficial effects do last quite a while, and this is presently a mystery - what mechanisms are mediating this result? This is the latest in a line of studies that examine this question, and the novel finding here is that the transplanted cells do leave behind a lingering population of new cells in the heart, but the nature of those cells is unexpected, which is perhaps why past studies have missed them:

In numerous clinical trials, researchers have injected patients with various types of progenitor cells to help heal injured hearts. In some cases, subjects have ended up with better cardiac function, but exactly how has been a subject of disagreement among scientists. According to study on rats, the introduced cells themselves don't do the job by proliferating to create new muscle. "These cells do not become adult cardiac myocytes. So the mechanism is clearly a paracrine action, where the cells release 'something' which makes the heart better. And the million-dollar question now is, 'What is the something?'"

Researchers investigated the fate of so-called c-kit+ cells, progenitors harvested from the heart and named for the presence of a particular kinase. These cells have been the source of a long debate about their role in building cardiac muscle, with some studies finding no evidence of them producing new cardiomyocytes in vivo and others concluding that, if the conditions are right, c-kit cells do indeed make heart muscle. C-kit cells have also been deployed in a clinical trial on heart attack patients. Studies on a variety of cardiac cell therapies have found that the vast majority of the cells don't stick around in the heart for much longer than a few weeks, suggesting that their mode of action is likely not based on the cells themselves producing new muscle tissue directly. To test whether that's the case with c-kit cells, researchers harvested c-kit cells from healthy male rats' hearts and injected them into female rats who had been made to have a heart attack.

Compared to controls, the treated rats had smaller scars, more muscle in their hearts, and improvements in cardiac function. To follow what had happened to the injected c-kit cells, the researchers picked out cells with Y chromosomes, finding that they made up 4 percent to 8 percent of the nuclei in the heart. Many of them had lost c-kit positivity, and it was clear from their morphology that these cells are not heart muscle and don't contribute to cardiac contraction. "Honestly, I do not know what they are. That's what we're trying to figure out." It appeared that the treated animals did have more cell proliferation, which researchers attributes to the cell therapy. "Pretty amazingly, it lasts up to 12 months after transplantation, which is another thing I cannot explain. How can the transplantation, done only once, stimulate a proliferative response for 12 months?"


The SENS Rejuvenation Biotechnology Companies

After the laboratory, the next stage of development in rejuvenation therapies involves the founding of biotechnology startups. There is no clear-cut point at which research stops being non-profit in the laboratory and starts being for-profit in a venture-funded startup. Every research team eyeballs the time and cost needed to get to the next level, something ready for the first human trial. Once that comes down to a gap that can be crossed with the combination of a seed round and angel investment round - say half a million to a million dollars and a year or two of work with a couple of clearly identifiable goals and go/no-go decisions - then the adventurous will make the leap. As I'm sure you've noticed it looks like a bear market is getting underway, but what better time to pull in investment for a project that might take a couple of years of heads-down work out of the limelight to reach the next stage? Bear markets only last a year or two, so by the time a new biotech startup has completed its first stage work successfully, it'll be ready to catch the headwinds of the next bull market.

Numerous lines of SENS rejuvenation research are, piece by piece, leaving the laboratory for the startup world. This is the success that we as a community have achieved with our years of charitable support for research aimed at advancing the state of the art. Whenever a new SENS-related biotechnology startup launches, bear in mind that a diverse group of people, investors and researchers, have looked at the technology and said "yes, we think can get a prototype therapy for human trials done in a couple of years." It is an important sign of progress, and one that is hard to fake: people with meaningful amounts of money on the line made those calls. You should expect our community to transition in part from one of fellow traveler non-profits and research groups to one made up equally of a network of startups, entrepreneurs, and investors of various stripes, from occasional angels to professionals at venture funds.

Here is a short list of interesting companies I am aware of that are working on SENS-related therapies at various stages, some very new, some years old, and proceeding at differing paces and with different strategies for development. They are not the only companies of interest to people who follow this space: I am omitting Arigos Biomedical, Organovo, and BioViva, among others, but the companies I list below are all very clearly working on aspects of SENS rejuvenation biotechnology. I'm certain there are others that I don't know about at this point - I am certainly far from well connected. I foresee a future in which in addition to the important work still ongoing in the laboratory, we can help to support a incubator-like environment of friendly companies under the SENS umbrella, helping one another succeed, each focused on one slice of the rejuvenation therapies needed to bring an end to aging. Those that succeed will act as guides for the growth of others: in diversity there is the greater chance of finding winning strategies. Importantly, among these companies today there are lot of people who are in this primarily to get the therapies built and out there and available. They are long-term SENS supporters. If they strike it rich, a good portion of that wealth is going to be reinvested in the next cycle of research development because, like us, they have a good idea of which of the two of life and money is more important. That is what success will look like once things become more commercial.


I've posted on the topic of Gensight in the past. This is a French company with tens of millions in venture funding that is built on technology for allotopic expression of mitochondrial genes originally partly funded by the SENS Research Foundation. They are focused on generating a robust commercial implementation for one mitochondrial gene, initially to deploy gene therapies to treat hereditary mitochondrial disease. Creating such a robust implementation is an important foundation for a future effort in which all mitochondrial genes can be backed up to the cell nucleus, and thus the contribution of mitochondrial DNA damage to aging can be eliminated.

Human Rejuvenation Technologies

Human Rejuvenation Technologies is a venture run by philanthropist Jason Hope, who you may recall funded a sizable chunk of the ongoing work on glucosepane cross-link breaking at the SENS Research Foundation back a few years ago. Glucosepane cross-link breaker drug candidates seem to be a few years in the future yet, so Human Rejuvenation Technologies is instead working with a drug candidate for clearing a form of metabolic waste key to plaque formation in atherosclerosis. This candidate is one of the results produced by the long-running SENS Research Foundation LysoSENS program.

Ichor Therapeutics

Ichor Therapeutics has been around for a couple of years, and has done a good job in setting a sustainable lab business on the side. The interesting work here, however, is the continuation of SENS research programs aimed at removing the buildup of A2E, one of the components of lipofuscin that builds up in cells and interferes with cellular garbage disposal. Unusually among the forms of cellular damage, even those involving buildup of metabolic waste such as lipofusin, A2E is linked very directly and solidly to some forms of age-related disease that involve retinal degeneration. In most cases the fundamental damage that causes aging is separated from the end stage of disease by lengthy and barely understood chains of cause and consequence, but here it is very clear that getting rid of A2E is a good thing.

Oisin Biotechnologies

Oisin Biotechnologies is developing a senescent cell clearance therapy, an approach to treating aging that has definitely arrived with a splash: there are multiple methods demonstrated in mice, and a number of different groups at the point of launching commercial development efforts. The company was funded more than a year ago by the Methuselah Foundation and SENS Research Foundation, and you'll be hearing much more about them in the year ahead, I predict.

Pentraxin Therapeutics

Pentraxin Therapeutics is the oldest and slowest of these companies, founded way back in 2001. The SENS-relevant work started in 2008 or 2009 with a partnership with GlaxoSmithKline to develop a treatment to clear transthyretin amyloid, a form of metabolic waste that builds up with age and is linked to cardiovascular disease, osteoarthritis, and death by heart failure in the oldest human beings. A human trial recently produced very positive results, showing significant clearance of amyloid in patients, and this is consequently probably the furthest advanced of all SENS technologies. Unfortunately it is also the most locked up within the slow regulatory system and a Big Pharma partnership. It is hard to say what is going to happen next here, but don't hold your breath expecting to see anything in the clinic soon.

Unity Biotechnology

Unity Biotechnology has emerged from the first successful efforts to clear senescent cells via gene therapy, back in 2011, as well as ongoing programs such as those of the Campisi laboratory. They have a sizable staff for a startup, good venture backing, and are developing treatments based on these methods, but which will be more suitable for use in human patients. You no doubt saw the full court press in the media put on by the various organizational backers of Unity earlier this week. It is great to see such a large number of people pushing the SENS line of damage repair as the approach to treatment of aging. As more companies reach the point of gaining support from deep pockets in the venture community, we will see more of this media attention for SENS-like rejuvenation therapies.

Cytomegalovirus Associated with Cognitive Decline in Aging

Researchers here find an association in an older study population between the presence of cytomegalovirus (CMV) - and other common herpesviruses - and the observed degree of cognitive decline. A good deal of evidence from past years supports the theory that CMV accelerates immune system aging, causing the immune system to devote ever more of its limited capacity to uselessly fighting CMV rather than productively carrying out its other tasks. Our immune response is incapable of clearing CMV from the body, and the virus lingers to return in force again and again regardless of the effort devoted to battle it. Since immune failure is a large component of age-related frailty, this is an important topic, and more consideration should be given to approaches that might fix the problem, such as selective destruction of CMV-focused immune cells to free up space for replacement with useful immune cells. As a further consideration, since portions of the immune system serve specialized support roles in brain tissue, it isn't a stretch to think that immune dysfunction may be a contributing cause of cognitive decline in aging.

Certain chronic viral infections could contribute to subtle cognitive deterioration in apparently healthy older adults. Many cross-sectional studies, which capture information from a single time point, have suggested a link between exposure to cytomegalovirus (CMV) and herpes simplex viruses (HSV) 1 and 2, as well as the protozoa Toxoplasma gondii and decreased cognitive functioning. "Our study is one of the few to assess viral exposure and cognitive functioning measures over a period of time in a group of older adults. It's possible that these viruses, which can linger in the body long after acute infection, are triggering some neurotoxic effects."

The researchers looked for signs of viral exposures in blood samples that were collected during the Monongahela-Youghiogheny Healthy Aging Team (MYHAT) study, in which more than 1,000 participants 65 years and older were evaluated annually for five years to investigate cognitive change over time. They found CMV, HSV-2 or toxoplasma exposure is associated with different aspects of cognitive decline in older people that could help explain what is often considered to be age-related decline. "This is important from a public health perspective, as these infections are very common and several options for prevention and treatment are available. As we learn more about the role that infectious agents play in the brain, we might develop new prevention strategies for cognitive impairment." Now, the researchers are trying to determine if there are subgroups of people whose brains are more vulnerable to the effects of chronic viral infection.


Towards Reversible Cryopreservation of Organs

There is a fairly strong connection between the small cryonics industry, focused on preserving the human mind following death in order to offer a chance at renewed life in a more technologically capable future, and present efforts to reversibly cryopreserve organs. The technologies used are much the same, and there is a fair degree of overlap in the people involved and the sources of funding. To my eyes success in organ cryopreservation, and consequent growth of an industry focused on making the logistics of transplantation and near future creation of new organs much easier, is the most plausible path to greater public acceptance of cryonics. When livers and hearts can be reliably vitrified, stored for years, and restored as needed, then it isn't a leap to understand that, with further progress and suitable techniques, this could be done for the brain as well.

Over the course of an average winter North American wood frogs, Rana sylvatica, may freeze solid several times. They are able to get away with this by replacing most of the water in their bodies with glucose mobilised from stores in their livers. That stops ice forming in their tissues as temperatures drop. When things warm up again, the frogsicles thaw out, with no evident ill effects. What frogs do without thinking, human researchers are trying, with a great deal of thinking, to replicate. The prize is not the freezing and reanimation of entire people but the long-term preservation of organs for transplant.

According to the World Health Organisation, less than 10% of humanity's need for transplantable organs is being met. The supply has fallen as cars have become safer and intensive-care procedures more effective, and part of what supply there is is lost for want of an instantly available recipient. Cooled, but not frozen, a donated kidney might last 12 hours. A donated heart cannot manage even that span. If organs could be frozen and then thawed without damage, all this would change. Proper organ banks could be established. No organs would be wasted. And transplants that matched a patient's requirements precisely could be picked off the shelf as needed. The problem is that water expands when it freezes. If that water is in living tissue, it does all sorts of damage in the process. But an alliance of experts, ranging from surgeons and biochemists to mechanical engineers and food scientists, is attempting to overcome this inconvenient fact. And, after years of labour, many of them think they are on the threshold of success, and that cryopreservation will soon become a valuable technology.

There are in fact many cryopreservationist ideas around - so many that some think a little co-ordination is in order. That is the purpose behind the Organ Preservation Alliance (OPA), an American charity. Last year it persuaded America's defence department, an organisation with an obvious interest in transplants, to seed seven cryopreservation-research teams with money. The XPRIZE Foundation is considering offering an award to any team that can transplant into five animals organs that have been cryopreserved for a week. The research-funding arm of the Thiel Foundation has given a grant to Arigos Biomedical, a firm working on high-pressure vitrification. New firms abound: Tissue Testing Technologies is working on ways of warming organs uniformly; Sylvatica Biotech is perfecting recipes for cryoprotectants; X-therma is attempting to mimic cryoprotective proteins. The cryopreservation race is on, then. And the winning post is the organ bank.


Enhanced Proteasomal Activity Restores Declining Self-Renewal in Aging Neural Stem Cells

The proteasome is a type of cellular structure tasked with breaking down damaged and unwanted proteins, its activities one part of a broad variety of maintenance mechanisms found inside the living cell. Today I'll point out the latest of a number of studies from recent years to investigate the underlying reasons for associations between declining cellular maintenance and specific aspects of degenerative aging. The researchers noted here have linked proteasomal activity to the vitality of neural stem cells. They show that both decline in aging, but the stem cells can be restored to more youthful vigor when proteasomes are artificially induced to pick up the slack once more.

Stem cells maintain tissues by providing a source of new cells and signals that influence cellular behavior. Even in the brain, stem cell populations deliver a supply of new neurons over time, and this is one of the sources of neural plasticity, the ability of the brain to change, learn, adapt, and (to a limited degree) repair itself. The activity of stem cell populations declines with advancing age, however, most likely a reaction to rising levels of cell and tissue damage. Less activity serves to reduce the risk of death by cancer, but at the cost of a faster decline into frailty and organ failure, the result of failing tissue maintenance. In the brain, this means a progressive loss of neural plasticity, and this is thought to contribute meaningfully to the development of neurodegenerative conditions. It probably has subtle and profound effects on the state of the human mind as well, beyond those caused by obvious structural failures in brain tissue, though that is far harder to prove one way or another.

As is the case for stem cell activity, proteasomal activity is also known to decrease in older tissues. All mechanisms of cellular maintenance go the same way, unfortunately, and this is a recurring theme in aging research. There are many who view aging as at least in part a garbage catastrophe: a downward spiral led by broken mechanisms and a growing inability to keep up. Many models of enhanced longevity have greater maintenance activities than their less fortunate peers. Naked mole rats for example, have very effective proteasomes. Aging is the accumulation of cell and tissue damage, and even repair systems get damaged - though in likelihood these age-related declines are not the direct results of damage, but rather mediated by a complex web of interacting signals and protein levels. For much of the past decade, some researchers have looked towards boosted maintenance, including increased proteasomal activity, as a possible way to slow the onset of aging or treat degenerative conditions. Despite a lot of research and many published papers, little concrete progress towards clinical translation of research has occurred on this front, however.

Essential role of proteasomes in maintaining self-renewal in neural progenitor cells

The breakdown of protein homeostasis has been suggested to be tightly associated with the aging process, because all cells have to keep a dynamic balance between protein synthesis and degradation in order to maintain their integrity and normal functions. In fast-proliferating cells, it is particularly crucial to recycle obsolete macromolecules to provide the raw materials for synthesis of subcellular compartments and molecules to satisfy the requirement of rapid proliferation and/or differentiation. Such a self-renewal ability of cells, however, is gradually compromised and eventually diminished with age. Hallmarks of aged cells include increased accumulation of hyper-oxidative, misfolded, or abnormally-aggregated proteins, all of which result from the dysfunctional cell clearance mechanisms, especially the protein degradation pathway.

The proteasome-dependent degradation is one of such cellular clearance mechanisms for retaining intracellular protein homeostasis, which targets and subsequently degrades damaged, misfolded or redundant proteins. The dysfunction of proteasomes, in turn, may contribute to the occurrence of many aging-related diseases. Various studies have shown that proteasomal activity might be compromised during the aging process in both animals and cells, given that its decrease has been found in a variety of aged tissues in humans, non-human mammals, and even in lower organisms such as fruit flies.

In this study, we investigated the role of proteasomes in self-renewal of neural progenitor cells (NPCs). Through both in vivo and in vitro analyses, we found that the expression of proteasomes was progressively decreased during aging. Likewise, proliferation and self-renewal of NPCs were also impaired in aged mice, suggesting that the down-regulation of proteasomes might be responsible for this senescent phenotype. We previously increased proteasomal activity in bone marrow stem cells by exogenously applying the proteasome activator 18α-GA or genetically over-expressing the β-subunit PSMB5, and found that both methods could effectively improve cell integrity and ameliorate replicative senescence, in addition to enhancements of cell survival and neuronal differentiation following the brain transplantation of PSMB5-overexpressing bone marrow stem cells. In the current study, we observed similar effects of 18α-GA on NPCs.

Lowering proteasomal activity by loss-of-function manipulations mimicked the senescence of NPCs both in vitro and in vivo; conversely, enhancing proteasomal activity restored and improved self-renewal in aged NPCs. These results collectively indicate that proteasomes work as a key regulator in promoting self-renewal of NPCs. This potentially provides a promising therapeutic target for age-dependent neurodegenerative diseases.

Iron Oxide Nanoparticles Reduce Oxidative Stress in Flies

Researchers have found that iron oxide nanoparticles can act in similar ways to cellular antioxidants such as catalase, soaking up oxidative molecules and reducing oxidative stress and consequent damage. To the degree that this helps mitochondria resist damage, or alters the behavior of mitochondria in a similar way to that of the activity of mitochondrial antioxidants like catalase, this should modestly slow aging. Indeed, that is the result observed here:

In a study on flies, researchers have found that nanoparticles could potentially extend lifespan. The team tested the effects of iron oxide (Fe3O4) nanoparticles on intracellular reactive oxygen species (ROS) levels and their biological consequences on several cell and animal models. Fe3O4 nanoparticles is a type of biocompatible nanomaterial that has previously been widely used for bioimaging, biodiagnostic and therapeutic purposes. Increased ROS production over time has been closely associated with greater risk of metabolic diseases such as type 2 diabetes and neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. Therefore, there is a need to explore the long-term effects of nanomaterials on intracellular ROS levels, particularly those with promising biomedical applications in vivo.

The researchers found that Fe3O4 nanoparticles could protect cultured cells under various stress conditions, including hydrogen peroxide (H2O2) treatment, through catalase-like activity. They demonstrated that Fe3O4 nanoparticles retained this mimetic activity in vivo, helping to maintain optimal ROS balance, reduce intracellular oxidative stress, suppress cellular damage, delay animal aging and protect against neurodegeneration. These novel effects were further confirmed in Drosophila models of aging, Parkinson's and Alzheimer's disease. The researchers hope that this study opens up new opportunities for the therapeutic use of Fe3O4 nanoparticles in the treatment of metabolic disorders, neurodegenerative diseases and aging.


Clearing Mitochondria Reverses Some Aspects of Cellular Senescence

Cellular senescence is a response to damage or environmental factors such as toxins, wounds, and oxidative stress. It removes cells from the processes of growth and replication, and probably serves, at least initially, as a way to reduce cancer risk. In this paper, researchers remove mitochondria from senescent cells and see measures of their state improve as a result. The publicity materials head in the wrong direction, I think, by talking about aging versus cellular senescence - these are two very different things, and the aging of individual cells has no direct relationship to aging of the organism.

Growth in the number of senescent cells lingering in tissues is a contributing cause of degenerative aging due to their overall bad behavior, but so is mitochondrial damage. This research could be taken as evidence for one way which mitochondrial damage and dysfunction is important in the mechanisms of aging, but it can also be taken as a straightforward improvement in the understanding of how cells manage their transition into senescence. In either case, we already know that both of these processes are targets for near future rejuvenation therapies.

A team of scientists has for the first time shown that mitochondria, the batteries of the cells, are essential for ageing. The researchers found that when mitochondria were eliminated from ageing, senescent cells they became much more similar to younger cells. This experiment was able for the first time to conclusively prove that mitochondria are major triggers of cell ageing. This brings scientists a step closer to developing therapies to counteract cellular senescence, by targeting mitochondria.

As we grow old, cells in our bodies accumulate different types of damage and have increased inflammation, factors which are thought to contribute to the ageing process. The team carried out a series of genetic experiments involving human cells grown in the laboratory and succeeded in eliminating the majority, if not all, the mitochondria from ageing cells. Cells can normally eliminate mitochondria which are faulty by a process called mitophagy. The scientists were able to "trick" the cells into inducing this process in a grand scale, until all the mitochondria within the cells were physically removed. To their surprise, they observed that the senescent cells, after losing their mitochondria, showed characteristics similar to younger cells, that is they became rejuvenated. The levels of inflammatory molecules, oxygen free radicals and expression of genes which are among the markers of cellular ageing dropped to the level that would be expected in younger cells.

The team also deciphered a new mechanism by which mitochondria contribute to ageing. They identified that as cells grow old, mitochondrial biogenesis, the complex process by which mitochondria replicate themselves, is a major driver of cellular ageing. "This is the first time that a study demonstrates that mitochondria are necessary for cellular ageing. Now we are a step closer to devising therapies which target mitochondria to counteract the ageing of cells."


25% Median Life Extension in Mice via Senescent Cell Clearance, Unity Biotechnology Founded to Develop Therapies

With today's news, it certainly seems that senescent cell clearance has come of age as an approach to treating aging and age-related conditions. Some of the leading folk in the cellular senescence research community today published the results from a very encouraging life span study, extending life in mice via a method of removing senescent cells. This is much the same approach employed in one of the first tests of senescent cell clearance, carried out in accelerated aging mice a few years ago, but in this case normal mice were used, leaving no room to doubt the relevance of the results. The researchers have founded a new company, Unity Biotechnology, to develop therapies for the clinic based on this technology. Clearance of senescent cells has been advocated as a part of the SENS vision for the medical control of aging for more than a decade now, and it is very encouraging to see the research and development community at last coming round to this view and making tangible progress.

Senescent cells have removed themselves from the cycle of replication in reaction to cell and tissue damage, or a local tissue environment that seems likely to result in cancer. Their numbers accumulate with age. Most are destroyed by the immune system or their own programmed cell death mechanisms, but enough linger for the long term for their growing presence to be one of the contributing causes of the aging process. These cells behave badly, secreting harmful signals that degrade tissue function, generate inflammation, and alter the behavior of surrounding cells as well. Near every common age-related condition is accelerated and made worse by the presence of large numbers of senescent cells. We would be better off without them, aging would be slowed by the regular removal of these errant cells, and the therapies to make that possible are on the near horizon.

The mouse lifespan study is the important news here, as it demonstrates meaningful extension of median life span through removal of senescent cells, the first such study carried out in normal mice for this SENS-style rejuvenation technology. This sort of very direct and easily understood result has a way of waking up far more of the public than the other very convincing evidence of past years. So it looks like Oisin Biotechnology, seed funded last year by the Methuselah Foundation and SENS Research Foundation to bring a senescent cell clearance therapy to market, now has earnest competition. Insofar as the competitive urge in business and biotechnology speeds progress and produces better results, let the games begin, I say.

Scientists Can Now Radically Expand the Lifespan of Mice - and Humans May Be Next

Researchers have made this decade's biggest breakthrough in understanding the complex world of physical aging. The researchers found that systematically removing a category of living, stagnant cells (ones which can no longer reproduce) extends the lives of otherwise normal mice by 25 percent. Better yet, scouring these cells actually pushed back the process of aging, slowing the onset of various age-related illnesses like cataracts, heart and kidney deterioration, and even tumor formation. "It's not just that we're making these mice live longer; they're actually stay healthier longer too. That's important, because if you were going to equate this to people, well, you don't want to just extend the years of life that people are miserable or hospitalized."

By rewriting a tiny portion of the mouse genetic code, the team developed a genetic line of mice with cells that could, under the right circumstances, produce a powerful protein called caspase when they start secreting p16. Caspase acts essentially as a self-destruct button; when it's manufactured in a cell, that cell rapidly dies. So what exactly are these circumstances where the p16 secreting cells start to create caspase and self-destruct? Well, only in the presence of a specific medicine the scientists could give the mice. With their highly-specific genetic tweak, the scientists had created a drug-initiated killswitch for senescent cells. In today's paper, the team reported what happened when the researchers turned on that killswitch in middle-aged mice, effectively scrubbing clean the mice of senescent cells.

Naturally occurring p16Ink4a-positive cells shorten healthy lifespan

Senescent cells accumulate in various tissues and organs over time, and have been speculated to have a role in ageing. To explore the physiological relevance and consequences of naturally occurring senescent cells, here we use a previously established transgene, INK-ATTAC, to induce apoptosis in p16Ink4a-expressing cells of wild-type mice by injection of AP20187 twice a week starting at one year of age. We show that AP20187 treatment extended median lifespan in both male and female mice of two distinct genetic backgrounds. The clearance of p16Ink4a-positive cells delayed tumorigenesis and attenuated age-related deterioration of several organs without apparent side effects, including kidney, heart and fat, where clearance preserved the functionality of glomeruli, cardio-protective KATP channels and adipocytes, respectively. Thus, p16Ink4a-positive cells that accumulate during adulthood negatively influence lifespan and promote age-dependent changes in several organs, and their therapeutic removal may be an attractive approach to extend healthy lifespan.

Unity Biotechnology Launches with a Focus on Preventing and Reversing Diseases of Aging

Unity will initially focus on cellular senescence, a biological mechanism theorized to be a key driver of many age-related diseases, including osteoarthritis, glaucoma and atherosclerosis. "Imagine drugs that could prevent, maybe even cure, arthritis or heart disease or loss of eyesight. It's an incredible aspiration. If we can translate this biology into medicines, our children might grow up in significantly better health as they age. There will be many obstacles to overcome, but our team is committed and inspired to achieve our mission. This has been a long journey, and we're at the point now where we can start making medicines to achieve in humans what we've achieved in mice. I can't wait to see what happens as we move into the clinic."

To close this post, and once again, I think it well worth remembering that SENS rejuvenation biotechnology advocates and supporters have been calling for exactly this approach to treating aging for more than a decade. That call was made based on the evidence arising from many fields of medical research, and from a considered perspective of aging as a process of damage accumulation, one that can be most effectively treated by repair of that damage. The presence of senescent cells is a form of damage. SENS was not so long ago derided and considered out on the fringe for putting forward that position, but for several years now it has been very clear that the SENS viewpoint was right all along. I strongly encourage anyone who remains on the fence about the validity of the SENS proposals for the treatment of aging to reexamine his or her position on the science.

Ampakine Prevents Loss of Dendrites in the Aging Rat Brain

The research community is very interested in loss of neural plasticity in the brain over the course of aging, a slowing of the introduction and integration of new neurons, and diminished pace of change in the connections between nerve cells. If aging is damage, then this is probably the tail end of a complicated chain of reactions to that damage. As seems to be the case for stem cell populations in other tissues, it is plausible that tinkering with signaling in brain tissue might be able to compensate for this loss, overriding some of this evolved reaction to damage without addressing the damage. The open question is the degree to which this approach can be effective; the evidence to date suggests it can produce large enough benefits in comparison to existing medicine to be worth trying, though if the underlying damage remains unrepaired, contributing to all of the other issues that accompany aging, then frailty and death is still inevitable.

As brain cells age they lose the fibers that receive neural impulses, a change that may underlie cognitive decline. Researchers recently found a way to reverse this process in rats. "There's a tendency to think that aging is an inexorable process, that it's something in the genes and there's nothing you can do about it. This paper is saying that may not be true." The researchers studied dendrites - the branch-like fibers that extend from neurons and receive signals from other neurons - in rats. Evidence from other studies in rodents, monkeys, and humans indicates that dendrites dwindle with age and that this process - called dendritic retraction - occurs as early as middle age.

The team wanted to know whether dendritic retraction was already underway in 13-month-old or "middle-aged" rats and, if it was, could they reverse it by giving rats a compound called an ampakine. Ampakines had previously been shown to improve age-related cognitive deficits in rats as well as increase production of a key growth factor, brain-derived neurotrophic factor (BDNF) in the brain. The researchers housed 10-month-old male rats in cages with enriched environments. Eleven rats received an oral dose of the ampakine each day for the next three months while the other 12 rats received a placebo. After three months the researchers examined an area of the rats' brains associated with learning and memory, the hippocampus, and compared that with the hippocampi of two-and-a-half-month-old or "adolescent" rats.

"Middle-aged" rats given the placebo had shorter dendrites and fewer dendritic branches than the younger rats. The brains of rats given the ampakine, however, were mostly indistinguishable from the young rats - dendrites in both were similar in length and in the amount of branching. What's more, the researchers also found that treated rats had significantly more dendritic spines, the small projections on dendrites that receive signals from other neurons, than either the untreated rats or the young rats. The researchers found that anatomical differences between the rats also correlated with differences in a biological measure of learning and memory: the treated rats showed enhanced signaling between neurons - a phenomenon called long-term potentiation. "The treated rats had better memory and developed strategies to explore."


On Developing a Stem Cell Therapy for Parkinson's Disease

This is an interesting short interview with a researcher working on aspects of a stem cell therapy for Parkinson's disease, with unusual results from animal studies in that the transplanted cells survive for a long time. In most first generation stem cell therapies, the cells produce benefits through signaling and do not live long or integrate with patient tissues in any significant numbers. Parkinson's is characterized by the loss of a small but vital population of neurons in the brain, something that happens in the course of normal aging as well, but not to the same degree. Thus for quite some time researchers have been aiming at replacement of these cells as a therapy:

Dr. Xianmin Zeng at The Buck Institute for Research on Aging focuses on potential treatments and therapies for Parkinson's disease. After years of dedicated work creating cell lines and collaborating on a delivery system the Zeng laboratory and their industry collaborators have developed a stem cell based treatment that is ready for human clinical trials. The treatment relies on a specialized process to make and purify nerve cells from induced pluripotent stem cells (iPSCs) which can be implanted into humans. In the process of creating the iPSCs multiple patient lines were also created resulting in an invaluable resource of a wide variety of Parkinson's patient lines. Having this vast variety of patient lines allows researchers to better understand the different mutations that can cause Parkinson's disease.

"Although the best-case scenario is having your own cells modified and implanted back into you, this is a therapy for only one person. An allogeneic donor line after being tested and verified can serve multiple patients. It is a bit like having a blood bank; one line of allogeneic cells will work for many patients, while another line of allogeneic cells will work for a different set of patients. The challenge is to calculate how many different allogeneic lines are needed to work with 90% of the patient population."

Another challenge with Parkinson's disease lies in delivering the desired treatment to the brain. These cells are able to populate the diseased area, differentiating into the appropriate cell type and replacing the dead neurons. One way in which this widespread delivery might be accomplished is to have a single injection that can be multi-pronged, reaching many areas of the brain. If this treatment works it could have a broad impact by serving as as a template to treat a variety of other neurodegenerative diseases. "It is not expected that you would need to do this treatment repeatedly. In the animal studies that we conducted the transplanted cells survived over six months. If one were to extrapolate this to human lifespan then it could be many years in which the cells will both survive and integrate into the brain after treatment."


Recent Research on Muscles, Stem Cells, and Aging

Today I thought I'd point out a few recent papers and publicity materials on muscle aging. A large chunk of the research into stem cell aging and changes in cell metabolism with aging focus on muscle tissue. In part this is a feedback loop: the better understood models and types of cell are found in or associated with muscle tissue. Therefore more researchers use this as a starting point, and therefore the knowledge grows faster than is the case for other tissue types. It doesn't hurt that muscle tissue is easily sampled and examined in people and animals, unlike the cell populations of internal organs. That reduces the cost across the board for many types of study, and researchers are very conscious of cost - there is no such thing as a laboratory with enough funding for optimal progress. Measured by deeds rather than words, our society places very little value on medical research, or indeed research at all for that matter. The investment that goes into building the scientific understanding necessary to produce better medicine is minuscule in the grand scheme of things. Thus a core skill for any scientist to be able to do more with less, because less is absolutely the state of things.

Muscle mass and strength diminishes with aging. It is called sarcopenia in those who suffer this loss to a significantly greater degree, and there has been an ongoing effort for the past decade to formally define this condition within the US regulatory system. That this process is still underway, and with no end in sight, is a sign of just how much that system holds back progress. It thus remains illegal to try to commercialize therapies for sarcopenia, and that is felt all the way back down the chain of research and development in the form of reduced availability of funding. There are many mechanisms involved in muscle degeneration in aging, ranging from the characteristic reduction in stem cell activity in old tissues to the effects of chronic inflammation, passing through mitochondrial dysfunction and numerous other metabolic changes that impair aspects of muscle growth or operation. As is always the case, definitively linking the observed changes into lines of cause and consequence is a challenge. Clinics will be repairing aging with SENS rejuvenation therapies long before the research community can produce a comprehensive, detailed model of aging that traces every step from fundamental damage through to final end stage of disease.

You may find the research linked here interesting, but remember that it's a thin slice of a large and diverse selection of scientific initiatives. These are small snapshots in an evolving album relating to muscle aging, and that in turn is but a small part of the larger field.

Regenerating damaged muscle after a heart attack

Researchers used human embryonic stem cells to create a kind of cell, called a cardiac mesoderm cell, which has the ability to turn into cardiomyocytes, fibroblasts, smooth muscle, and endothelial cells. All these types of cells play an important role in helping repair a damaged heart. As those embryonic cells were in the process of changing into cardiac mesoderms, the team was able to identify two key markers on the cell surface. The markers, called CD13 and ROR2, pinpointed the cells that were likely to be the most efficient at changing into the kind of cells needed to repair damaged heart tissue. The researchers then transplanted those cells into an animal model and found that not only did many of the cells survive but they also produced the cells needed to regenerate heart muscle and vessels.

"In a major heart attack, a person loses an estimated 1 billion heart cells, which results in permanent scar tissue in the heart muscle. Our findings seek to unlock some of the mysteries of heart regeneration in order to move the possibility of cardiovascular cell therapies forward. We have now found a way to identify the right type of stem cells that create heart cells that successfully engraft when transplanted and generate muscle tissue in the heart, which means we're one step closer to developing cell-based therapies for people living with heart disease."

The ins and outs of muscle stem cell aging

Skeletal muscle has a remarkable capacity to regenerate by virtue of its resident stem cells (satellite cells). This capacity declines with aging, although whether this is due to extrinsic changes in the environment and/or to cell-intrinsic mechanisms associated to aging has been a matter of intense debate. Furthermore, while some groups support that satellite cell aging is reversible by a youthful environment, others support cell-autonomous irreversible changes, even in the presence of youthful factors. Indeed, whereas the parabiosis paradigm has unveiled the environment as responsible for the satellite cell functional decline, satellite cell transplantation studies support cell-intrinsic deficits with aging.

In this review, we try to shed light on the potential causes underlying these discrepancies. We propose that the experimental paradigm used to interrogate intrinsic and extrinsic regulation of stem cell function may be a part of the problem. The assays deployed are not equivalent and may overburden specific cellular regulatory processes and thus probe different aspects of satellite cell properties. Finally, distinct subsets of satellite cells may be under different modes of molecular control and mobilized preferentially in one paradigm than in the other. A better understanding of how satellite cells molecularly adapt during aging and their context-dependent deployment during injury and transplantation will lead to the development of efficacious compensating strategies that maintain stem cell fitness and tissue homeostasis throughout life.

Hypothesis on Skeletal Muscle Aging: Mitochondrial Adenine Nucleotide Translocator Decreases Reactive Oxygen Species Production While Preserving Coupling Efficiency

Mitochondrial membrane potential is the major regulator of mitochondrial functions, including coupling efficiency and production of reactive oxygen species (ROS). Both functions are crucial for cell bioenergetics. We previously presented evidences for a specific modulation of adenine nucleotide translocase (ANT) appearing during aging that results in a decrease in membrane potential - and therefore ROS production - but surprisingly increases coupling efficiency under conditions of low ATP turnover. Careful study of the bioenergetic parameters of isolated mitochondria from skeletal muscles of aged and young rats revealed a remodeling at the level of the phosphorylation system, in the absence of alteration of the inner mitochondrial membrane (uncoupling) or respiratory chain complexes regulation.

For equivalent ATP turnover (cellular ATP demand), coupling efficiency is even higher in aged muscle mitochondria, due to the down-regulation of inner membrane proton leak caused by the decrease in membrane potential. In the framework of the radical theory of aging, these modifications in ANT function may be the result of oxidative damage caused by intra mitochondrial ROS and may appear like a virtuous circle where ROS induce a mechanism that reduces their production, without causing uncoupling, and even leading in improved efficiency. Because of the importance of ROS as therapeutic targets, this new mechanism deserves further studies.

Mitochondrial Quality Control and Muscle Mass Maintenance

Loss of muscle mass and force occurs in many diseases such as disuse/inactivity, diabetes, cancer, renal, and cardiac failure and in aging - sarcopenia. In these catabolic conditions the mitochondrial content, morphology and function are greatly affected. The changes of mitochondrial network influence the production of reactive oxygen species (ROS) that play an important role in muscle function. Moreover, dysfunctional mitochondria trigger catabolic signaling pathways which feed-forward to the nucleus to promote the activation of muscle atrophy. Exercise, on the other hand, improves mitochondrial function by activating mitochondrial biogenesis and mitophagy, possibly playing an important part in the beneficial effects of physical activity in several diseases. Optimized mitochondrial function is strictly maintained by the coordinated activation of different mitochondrial quality control pathways. In this review we outline the current knowledge linking mitochondria-dependent signaling pathways to muscle homeostasis in aging and disease and the resulting implications for the development of novel therapeutic approaches to prevent muscle loss.

Proposing a Role for Acetylation in the Damage of Aging

Researchers here investigate fruit flies in search of age-related changes in the cellular processes of metabolism that occur in mid-life, early signs of degeneration and damage accumulation. They find that an increase in acetylation that occurs with aging may act to both alter and raise the error rate of protein creation, leading to an increased number of damaged proteins and inappropriate levels of proteins in circulation. In support of this hypothesis, it is noted that more acetylation reduces fly life span, while suppressing the age-related rise in acetylation increases life span:

The aging process is accompanied by characteristic changes in physiology whose overall effect is to decrease the capacity for tissue repair and increase susceptibility to metabolic disease. In particular, the overall level of metabolic activity falls, and errors in the regulation of gene activity become more frequent. Researchers have now shown in the fruitfly Drosophila melanogaster that such age-dependent changes are already detectable in middle age. Genetic investigation of the signal pathways involved in mediating this effect identified a common process - the modification of proteins by the attachment of so-called acetyl groups (CH3COO−) to proteins - that links the age-related changes at the metabolic and genetic levels. Most studies of the aging process employ comparisons between young and old individuals belonging to the same species. "However, in aged animals, many of the potentially relevant physiological operations no longer function optimally, which makes it difficult to probe their interactions. That is why we chose to look in Drosophila to see whether we could find any characteristic metabolic changes or other striking modifications in flies on the threshold of old age and, if so, ask how these processes interact with each other."

Resarchers first made the surprising discovery that middle-aged male flies (7 weeks old) actually consume more oxygen than their younger counterparts. This points to a metabolic readjustment which is accompanied by an increase in mitochondrial activity, and indeed, the researchers noted a rise in the intracellular concentration of acetyl-CoA in these flies. Acetyl-CoA is a metabolite that is produced in the mitochondria, which participates in large number of processes in energy metabolism. Furthermore, it is an important source of acetyl groups for the chemical modification of proteins. "Acetyl groups are attached to specific positions in certain proteins by dedicated enzymes, and can be removed by a separate set of enzymes. These modifications modulate the functions of the proteins to which they are added, and our experiments have shown that many proteins are much more likely to be found in acetylated form in middle-aged flies than in younger individuals."

Strikingly, this is true not only for proteins that are involved in basic metabolism, but also for proteins that are directly responsible for regulating gene expression. "We were able to show that the histones in middle-aged flies are overacetylated. This reduces the packing density of the DNA, and with it the stringency of gene regulation. The overall result is a rise in the level of errors in the expression of the genetic information, because genetic material that should be maintained in a repressed state can now be reactivated. In the prime of their lives, fruitflies begin to produce a surfeit of acetylated proteins, which turns out to be too much of a good thing."

Taken together, these findings indicate that changes in acetylation may be a key factor in the process of natural aging, reflecting alterations in basic metabolism as well as modifying gene regulation. "A rise in the level of protein acetylation seems to be linked to a decrease in life expectancy. For inhibition of an acetylase enzyme which specifically attaches acetyl groups to histones, or attenuation of the rate of synthesis of acetyl-CoA - which reduces the supply of acetyl groups - reverses many of the age-dependent modifications seen in these animals, and both interventions are associated with a longer and more active lifespan." The researchers are now planning to look for comparable effects in mammals. "If that turns out to be the case, then the enzymes that specifically acetylate histones might well be interesting targets for the development of novel therapeutic agents that correct age-dependent dysregulation. Partial inhibitors that reduce enzyme activity without completely blocking it would probably be most effective in this context."


Model of Protein Charge Predicts Aging Associated Proteins

Researchers here use a model to predict aging-associated proteins, those in which damaged and misfolded molecules are noticeable prevalent in aged tissues. Since the model turns up proteins already known to be associated with aging, some of the others in the list may also be worth looking at, and the overall effort can be taken as supporting evidence for some theories on the relative importance of various mechanisms in aging:

Certain proteins known to be associated with aging and age-related diseases such as Alzheimer's disease and cancer are also at a high risk for destabilization caused by oxidation. This finding provides an understanding of how oxidative damage, which is a natural process in aging cells, affects proteins. It could also prove to be a foundation to a better understanding of age-related diseases. When people turn about 80 years of age, approximately half of the body's proteins are damaged by oxidation. Oxidation occurs because of random chemical degradations that are associated with converting food to energy in the presence of oxygen. Oxidation in the human body, mediated by free radicals, damages cellular proteins, lipids, DNA, and other cellular structures that contribute to disease processes.

Researchers used physics principles and computer analysis to evaluate protein electrostatics, or charges. They found that short, highly charged proteins are particularly susceptible to large destabilization and that even a single oxidation event within these proteins is sufficient to unfold its normally balled-up, folded structure. "Our paper explains the molecular mechanism by which natural chemical processes of aging affect our proteins. Our method predicts which proteins are the most at risk of unfolding when they get damaged. We then applied the principle in searching protein databases. Interestingly, we found that the proteins most at-risk for oxidative unfolding included 20 proteins that span a wide-spectrum of functionalities, all of which had been known by researchers previously to be associated with aging." The list of proteins includes telomerase proteins, which play a major role in aging of cells and cancer development by the extending of telomeres; and histones, which are DNA-binding proteins known to be relevant for many processes, including memory loss and cancer. The research could be a first step toward finding other proteins, not currently suspected, that are susceptible to high oxidation, instability and age-related diseases. The proteins could prove to be the key to targeted treatments against certain age-related diseases.


What Next for Transthyretin Amyloid Clearance Therapies?

If aging is damage, specific forms of cellular and molecular disarray, then rejuvenation is achieved through periodic repair of that damage. This is the Strategies for Engineered Negligible Senescence (SENS) vision for the future of treating aging, and it is a task that the medical research community is only just getting started on in any real way, sad to say. We are more than a decade in to advocacy and modest funding for SENS, and some progress has been achieved, however. Setting aside stem cell research and the amyloid clearing efforts of the Alzheimer's research community, as in both of those cases it is very hard to pick out the thin threads of rejuvenation biotechnology from other research that tries to compensate for damage or patch over damage, there are four SENS rejuvenation biotechnologies presently somewhere in the cusp between the laboratory and the clinic, in commercial development, and a fifth very close to that status.

Senescent cell clearance is achieved via several methods in rodents, and at least one company, Oisin Biotechnology, has been seed funded to bring such a therapy to market. Creating backup mitochondrial genes in the cell nucleus is still a matter of one gene at a time, but the technology to do that is at a comparatively advanced stage of commercial development at Gensight. Breaking down metabolic waste that contributes to atherosclerosis via the use of modified bacterial enzymes is an approach that recently moved from the SENS Research Foundation laboratories into development at Human Rejuvenation Technologies. The technology close to commercial development but not there yet is glucosepane cross-link clearance; based on recent discussions, it seems only a few years away from a viable drug candidate.

The topic for today, however, is transthyretin amyloid clearance, arguably the most advanced of the five SENS rejuvenation biotechnologies I've listed here. Amyloids are made up of misfolded proteins that in their damaged form precipitate from solution to form clumps and fibrils. There are a score of different types - the beta amyloid most people are familiar with, associated with Alzheimer's disease, is just one of them. In recent years, it has become clear that another type, transthyretin amyloid, is associated with heart failure, osteoarthritis, and a range of other conditions. In the oldest of humans, the small supercentenarian population, accumulation of transthyretin amyloid appears to be the predominant cause of death.

The small company Pentraxin signed up with GlaxoSmithKline back in 2009 to commercialize CPHPC as a treatment for transthyretin amyloidosis, a runaway version of the standard age-related accumulation of amyloid in which much more deposition occurs at a younger age, accompanied by organ failure and ultimately death. CPHPC works by clearing serum amyloid P component (SAP), a molecule associated with amyloid deposits and which seems to inhibit the normal processes of amyloid clearance. This therapy had been presented at the 4th SENS conference that same year. Like many lines of research in the Big Pharma world, this collaboration has moved forward only glacially since then, but it is moving. Along the way the use of CPHPC merged with another treatment based on the use of antibodies for SAP, and a small clinical trial of the combination therapy concluded with very positive results last year.

What next from here? At this point, a therapy exists that can, from a technical perspective, be deployed in humans with the expectation that it will clear meaningful amounts of transthyretin amyloid, with resulting improvement in the condition of patients. Unfortunately this is still very much locked up in the slow development processes at GSK, which most likely means years of trials yet, and no real urgency to move this out into the world. There is every reason to expect benefits to heart health over the long-term to result from periodic removal of transthyretin amyloid, and this is a technology I'd rather see widely used in clinics overseas, available via medical tourism, today, as opposed to being locked up behind closed regulatory doors. That outcome isn't in the GSK worldview, unfortunately, which means it will probably be an overly long time before these approaches reach the clinic. Meanwhile, diversification is a focus: finding more niches and potentially more lucrative niches in which to seek regulatory approval.

Pentraxin R&D Programmes

The single dose first in human study of anti-SAP antibodies co‑administered with CPHPC in patients with systemic amyloidosis remains currently underway. The initial results in the first 15 subjects to be treated have been accepted for publication and were be posted online in July 2015. The treatment has been safe and well tolerated so far and has produced unequivocal and unprecedented, swift and dramatic reduction in amyloid load, documented so far in the liver, spleen, kidneys and lymph nodes. Cardiac amyloidosis was excluded from the first part of the phase I study but subjects with cardiac involvement are now being treated.

Meanwhile alternative, novel immunotherapy approaches to treatment of amyloidosis are also being actively investigated. In a first clinical study of CPHPC in Alzheimer's disease we have shown that the drug safely and completely depletes SAP from the cerebrospinal fluid. We have now designed a comprehensive clinical trial of CPHPC in Alzheimer's disease, seeking evidence of disease modification and clinical efficacy. Preparation for and conduct of the 'Depletion of serum amyloid P component in Alzheimer's disease (DESPIAD) trial' is receiving substantial logistical and expert support from GSK and is being funded by the UCL/UCLH Biomedical Research Centre. It will start in 2016 and run to 2019.

There are alternative approaches to clearing transthyretin amyloidosis, such as the work on catalytic antibodies funded by the SENS Research Foundation. The expectation is that those, too, will be adopted by developers who set out to run the slow gauntlet of regulation, taking years longer than required for simple, sane considerations of safety and efficacy in order to get into the clinic. Even then therapies are only approved in a very limited way, and are made far more expensive by excessive regulatory costs. To my eyes the future needs much more of the distributed development and commercialization process that happened for stem cell medicine following the turn of the century, and is happening now for CRISPR gene therapies: many clinics offering services outside the restrictive regulation of the FDA and related agencies, building a market in which people can make their own informed choices on risk and early adoption, rather than being held back by the actions of self-serving, distant, and unaccountable bureaucrats.

21st Century Medicine Mentioned in Scientific American

The popular scientific press here looks at the work of 21st Century Medicine on cryopreservation. Specifically, the topic is the present efforts to provide conclusive proof that low-temperature vitrification of tissue, the process employed at Alcor and other cryonics providers, maintains the fine structures of the brain considered to encode the data of the mind, such as memory. For the many who will die prior to the advent of rejuvenation biotechnologies, this is the only shot at a longer life in the future, and it is to our shame as a society that so few choose this option over oblivion and the grave.

It is interesting to note that many of the people in this field, and their supporters, see the end goal as scanning and transcription of the data encoded in a stored brain into an emulated mind running in software. This is as opposed to restoration and repair of the original tissue via advanced forms of molecular nanotechnology and tissue engineering. The assumption of an emulated copy is very much in evidence in this article. I think this to be a profoundly mistaken strategic goal, as a copy of you is not you.

The soul is the pattern of information that represents you - your thoughts, memories and personality - your self. There is no scientific evidence that something like soul stuff exists beyond the brain's own hardwiring, so I was curious to visit the laboratories of 21st Century Medicine in Fontana, Calif., to see for myself an attempt to preserve a brain's connectome - the comprehensive diagram of all neural synaptic connections. This medical research company specializes in the cryopreservation of human organs and tissues using cryoprotectants (antifreeze). In 2009, for example, the facility's chief research scientist Gregory M. Fahy published a paper documenting how his team successfully transplanted a rewarmed rabbit kidney after it had been cryoprotected and frozen to −135 degrees Celsius through the process of vitrification, "in which the liquids in a living system are converted into the glassy state at low temperatures."

I witnessed the infusion of a rabbit brain through its carotid arteries with a fixative agent called glutaraldehyde, which binds proteins together into a solid gel. The brain was then removed and saturated in ethylene glycol, a cryoprotective agent eliminating ice formation and allowing safe storage at −130 degrees C as a glasslike, inert solid. At that temperature, chemical reactions are so attenuated that it could be stored for millennia. Think of a book in epoxy resin hardened into a solid block of plastic. "You're never going to open the book again, but if you can prove that the epoxy doesn't dissolve the ink the book is written with, you can demonstrate that all the words in the book must still be there ... and you might be able to carefully slice it apart, scan in all the pages, and print/bind a new book with the same words." The rabbit brain circuitry he examined through a 3-D scanning electron microscope "looks well preserved, undamaged, and it is easy to trace the synaptic connections between the neurons."


FGF21 in Calorie Restriction Compared in Mice and Humans

Increased gene expression of FGF21 is associated with calorie restriction and extends life in mice when artificially induced, such as via gene therapy. Researchers here find that the FGF21 response to calorie restriction in humans is quite different, which is a start on the journey to explain exactly how it is that calorie restriction has a much larger effect on mouse life span than on human life span, while the short-term benefits observed to date in both species are very similar:

The adaptive response to starvation includes a series of key physiologic changes in fuel utilization. Certain aspects of the starvation response, such as the depletion of adipose lipid stores and serum triglycerides, could, in theory, provide metabolic benefits if recapitulated outside the context of starvation, such as in obese individuals. This concept underscores the intense excitement elicited by the discovery of FGF21, a novel fasting-induced hormone in murine models. Having been ascribed a central role in coordinating the ketogenic response to starvation, FGF21 also mediates additional metabolically beneficial functions in mice. Although such preclinical mouse data provided a rationale to develop FGF21 or FGF21 mimetics to treat human metabolic disease, the very question of whether FGF21 is a fasting-induced hormone in humans has remained unresolved.

In this study, in which healthy volunteers underwent a prolonged, medically supervised fast, we provide strong evidence for induction of FGF21 over a 10-day period. By documenting the serial dynamics of circulating FGF21, we provide insight into why it has been so challenging to establish FGF21 as a fasting hormone in humans: namely, the protracted time scale necessary to elucidate the response. Not only did it take the full 10 days to demonstrate a statistically meaningful induction of FGF21, but we also observed an initial decline in FGF21 levels in the majority of subjects.

In considering potential explanations for the differing dynamics of circulating FGF21 between mice and humans, it is tempting to invoke the divergent metabolic rates between the 2 species. Indeed, the mass-specific resting metabolic rate of mice exceeds that of humans by a factor of approximately 7, which approximates the time-scale difference in the FGF21 effect between mice and humans. Our data, however, suggest that the difference between mice and humans with respect to FGF21 regulation and function may go beyond the time course of its release into the circulation. In contrast to the pattern observed in fasting mice, the ketogenic response in our human subjects preceded the induction of FGF21. Importantly, in several patients, the onset of ketosis occurred at a time point when serum FGF21 levels had dropped below baseline values. While this study does not exclude the possibility that FGF21 promotes ketone production in some contexts these data argue strongly against a paradigmatic role for FGF21 as a determinant of the human ketogenic response to starvation.

The late increase in FGF21 levels in humans correlated with weight loss and markers of tissue stress, providing a rationale to focus future mechanistic studies on the role of FGF21 in regulating fuel production and trafficking during the latter phase of starvation, with a particular focus on human studies, given the apparent evolutionary divergence in some FGF21 functions between mice and humans. With regard to the potential therapeutic implications of this study, we cannot assume that any hypothesized functional roles of FGF21 in the starved state are relevant to supraphysiologic administration of FGF21 mimetics in patients with metabolic disease.