Salicylates as an Autophagy Based Approach to Modestly Slow Aging in Nematodes

A sizable fraction of the many methods demonstrated to slow aging and increase longevity in nematode worms involve increased levels of autophagy. This collection of cellular maintenance and recycling mechanisms becomes more active following any sort of cellular stress, from heat to toxicity to lack of nutrients. Life span in short lived species is highly plastic in response to environmental circumstances; any minor stress can produce a net benefit. This can make it somewhat challenging to determine whether any particular approach shown to slow aging is in fact acting directly or indirectly via the controlling mechanisms of autophagy, or just stressing cells in some novel way. In the case of salicylates, a category that includes acetylsalicylic acid, better known as aspirin, there is by now enough data to be more certain about what is going on under the hood, however.

It is known that salicylates have beneficial activity on several pathways implicated in inflammation. For example, acetylsalicylic acid (ASA) is known to act as an anti-inflammatory. Interestingly, salicylates and other nonsteroidal anti-inflammatory drugs were also shown to extend lifespan of yeast and fly through inhibition of tryptophan uptake. Salicylates have also been shown to activate the adenosine monophosphate-activated protein kinase (AMPK) pathway, which has been suggested to control the aging process in general. Targeting AMPK has been discussed as a potential strategy to slow down aging in humans.

Interestingly, ASA has recently been revealed as a lifespan-extending treatment in both mice and nematodes. Salicylic acid also extends lifespan of C. elegans, albeit with a less pronounced effect than ASA. Work on the molecular mechanism in C. elegans has shown that activation of AAK-2/AMPK and DAF-16/FOXO was required for the lifespan-extending activity of ASA. These results led us to investigate in the present work another salicylic acid derivate, 5-octanoyl salicylic acid (referred to as C8-SA).

Unlike for ASA or salicylic acid, no anti-inflammatory activity has been detected for C8-SA. However, we were able to show that C8-SA displays a similar activity to ASA with regard to lifespan in the roundworm Caenorhabditis elegans. C8-SA activates AMPK and inhibits TOR both in nematodes and in primary human keratinocytes. We also show that C8-SA can induce both autophagy and the mitochondrial unfolded protein response (UPRmit) in nematodes. This induction of both processes is fully required for lifespan extension in the worm. In addition, we found that the activation of autophagy by C8-SA fails to occur in worms with compromised UPRmit, suggesting a mechanistic link between these two processes.


Dietary Fiber in the Context of Gut Bacteria, Inflammation, and Aging

Gut microbes have some level of influence over the pace of natural aging. It isn't yet clear as to how large this influence might be, but it may well turn out to be of a similar magnitude to that of exercise. Identifying the most important mechanisms by which the microbiota of the gut affect aging is an ongoing process, still in its comparatively early stages. Many researchers are, quite reasonably, focused on inflammation as a primary concern. Inflammation rises with age, and accelerates the development of all of the common age-related conditions. Scientists are thus attempting to trace back the ways in which different bacterial populations and byproducts can spur the immune system into inappropriate chronic inflammation, and link those mechanisms with known dietary changes and bacterial population changes that take place in later life.

As mammals age, immune cells in the brain known as microglia become chronically inflamed. In this state, they produce chemicals known to impair cognitive and motor function. That's one explanation for why memory fades and other brain functions decline during old age. Dietary fiber promotes the growth of good bacteria in the gut. When these bacteria digest fiber, they produce short-chain fatty acids (SCFAs), including butyrate, as byproducts. "Butyrate is of interest because it has been shown to have anti-inflammatory properties on microglia and improve memory in mice when administered pharmacologically."

Although positive outcomes of sodium butyrate - the drug form - were seen in previous studies, the mechanism wasn't clear. A new study reveals, in old mice, that butyrate inhibits production of damaging chemicals by inflamed microglia. One of those chemicals is interleukin-1β, which has been associated with Alzheimer's disease in humans. Understanding how sodium butyrate works is a step forward, but the researchers were more interested in knowing whether the same effects could be obtained simply by feeding the mice more fiber.

The concept takes advantage of the fact that gut bacteria convert fiber into butyrate naturally. Butyrate derived from dietary fiber should have the same benefits in the brain as the drug form, but no one had tested it before. The researchers fed low- and high-fiber diets to groups of young and old mice, then measured the levels of butyrate and other SCFAs in the blood, as well as inflammatory chemicals in the intestine. "The high-fiber diet elevated butyrate and other SCFAs in the blood both for young and old mice. But only the old mice showed intestinal inflammation on the low-fiber diet. It's interesting that young adults didn't have that inflammatory response on the same diet. It clearly highlights the vulnerability of being old." On the other hand, when old mice consumed the high-fiber diet, their intestinal inflammation was reduced dramatically, showing no difference between the age groups. The researchers examined about 50 unique genes in microglia and found the high-fiber diet reduced the inflammatory profile in aged animals.


A Primitive Form of Memory Exhibited by the Innate Immune System may Contribute to the Overall State of Immune Aging

The innate immune system evolved long before the adaptive immune system arose as a more sophisticated layer atop it. It is generally considered that only jawed vertebrates have an adaptive immune system, but there are interesting examples of stranger, adaptive-like innate immune systems in some of the more ancient jawless vertebrate lineages, such as lampreys. An overly simplistic view of the difference between innate and adaptive immunity is that the innate immune response is always the same, that for a given stimulus it will respond in the same way tomorrow as it does today. The adaptive immune system, on the other hand, maintains a memory. It will respond far more quickly and efficiently to any future incidence of a stimulus that it has encountered in the past.

Nothing in biology is simple, however. Researchers have become aware that the innate immune response in mammals can in fact change over time in response to stimuli, a phenomenon termed trained immunity. This appears to be an epigenetic process, and thus may or may not be truly lasting for any given individual - it may fade over time, if the stimulus is removed. Nonetheless, in the open access commentary noted below, researchers suggest that trained immunity may contribute to the age-related decline of the immune system into chronic inflammation and incapacity.

The impact of persistent infection or overall lifetime burden of infection on immune aging is more usually considered in terms of its effects on the adaptive immune system. Since the supply of new T cells declines with age as the thymus atrophies, the adaptive immune system behaves ever more like a resource-limited system. Only so many T cells that can become devoted to memory or to specific threats before there are too few naive T cells remaining to effectively tackle new pathogens. Prevalent and persistent herpesviruses such as cytomegalovirus are considered to be the most important burden in this sense, and the immune system uselessly devotes ever more resources to futile attempts to remove these viruses. It is interesting to consider that an analogous harmful reaction to persistent infection may be taking place in the innate immune system as well.

Be aware, innate immune cells remember

Aging is one of the most powerful independent risk factors for the development of atherosclerosis. Among many other explanations, this could be driven by age-related changes in the immune system. Systemic inflammation contributes to atherogenesis and an increased low-level inflammation during the aging process ("inflammaging") has been proposed as a culprit for many age-related diseases. Monocyte-derived macrophages are the most abundant immune cells in atherosclerotic plaques, and are key to the formation, growth, and rupture of these lesions. Monocyte production capacity for several pro-atherogenic inflammatory cytokines was higher with increasing age.

In the past few years, three novel mechanisms have been proposed to contribute to this age-related activation of the innate immune system. First, cellular senescence, a permanent arrest of cell growth, is associated with an enhanced secretion of pro-inflammatory mediators, e.g. cytokines. Secondly, due to an accumulation of acquired mutations in hematopoietic stem cells that confer a competitive advantage, more than 10% of subjects aged over 70 years have significant amounts of mutant clones in peripheral leukocytes, which is called clonal hematopoiesis of indeterminate potential (CHIP). CHIP is associated with an increased risk for cardiovascular disease because these clonal leukocytes have an increased NLRP3 inflammasome-mediated interleukin-1β secretion. Thirdly, we and others have described that innate immune cells can effectively build a non-specific immunological memory that results in an increased proinflammatory phenotype, a process which is termed trained immunity.

Recent studies have shown that circulating monocytes and myeloid progenitor cells in the bone marrow have the intriguing capacity to reprogram towards a long-term non-specific pro-inflammatory phenotype following initial exposure to microorganisms or microbial products. Although beneficial in the context of resistance against reinfections, this mechanism might be detrimental in non-infectious chronic inflammatory conditions in which myeloid cells contribute to disease progression, such as atherosclerosis. We have recently proposed this mechanism to contribute to the well-known association between acute and chronic infections and atherosclerosis. Interestingly, trained immunity is not only induced by microbial products, but also by endogenous sterile atherogenic stimuli such as oxidized low-density lipoprotein (oxLDL) or lipoprotein(a).

Osteoporosis Linked with Increased Risk of Later Development of Dementia

The pace of aging varies to some degree between individuals, largely a result of differences in lifestyle and choice. Genetics only begins to significantly influence the outcome at a very late age, and by that time it becomes a question of resilience to high levels of molecular damage. Between 60 and 80, the span of time in which age-related diseases become very prevalent given today's state of medical science, it is the case that very few people can claim genetics to have a significant contribution to their present state of health.

Of the unifying mechanisms one can invoke to explain links between lifestyle and pace of aging, chronic inflammation and raised blood pressure are two of the obvious choices. These two contribute in some way to all of the common age-related conditions, directly or indirectly. So when faced with an epidemiological study that shows a broad correlation between existing osteoporosis and risk of later dementia, chronic inflammation is the obvious candidate. There is plenty of evidence for it to contribute to both disruption of bone maintenance and the progression of neurodegeneration, and lifestyle choices such as exercise and weight gain both strongly influence the state of chronic inflammation in later life.

"There is big interest in the relationship between osteoporosis and dementia. This study is the first to address this question in a very large database enabling the case-control-comparison between patients with and without osteoporosis." This retrospective cohort study used data from the Disease Analyzer database (IQVIA), which compiles information on drug prescriptions, diagnoses, and demographic data obtained directly and in anonymous format from computer systems used by general practitioners and specialists. This database has already been used in several studies focusing on osteoporosis and dementia in recent years.

The study included patients diagnosed with osteoporosis between January 1993 and December 2012 (index date) and were followed for up to 20 years. After applying similar inclusion criteria, controls were matched (1:1) to osteoporosis patients using propensity scores based on age, gender, index year, several comorbidities, and co-therapies. The main outcome of the study was to determine the proportion of patients with all-cause-dementia diagnoses within 20 years of the index date.

The study included 29,983 patients with osteoporosis and 29,983 controls without osteoporosis. After 20 years of follow-up, 20.5% of women with osteoporosis and 16.4% of controls had been diagnosed with dementia. At the end of the follow-up period, dementia was found in 22.0% of men previously diagnosed with osteoporosis and 14.9% of men without this chronic condition. Osteoporosis was associated with a 1.2-fold increase in the risk of being diagnosed with dementia in women and a 1.3-fold increase in the risk of being diagnosed with dementia in men.

"The major hypothesis to explain the association between osteoporosis and dementia is that these two conditions have similar risk factors. These factors include APOE4 allele of the apolipoprotein E, a major cholesterol carrier, lower vitamin K levels, vitamin D deficiency, but also androgens and estrogens." The main limitations of the study are missing data on bone mineral density and on lifestyle-related risk factors (e.g., smoking, alcohol, and physical activity).


An Independent Group Working on a LysoSENS Medical Bioremediation Program

This is an interesting and welcome development; a group independent of the SENS Research Foundation and its scientific network has chosen of their own accord to work on one of the LysoSENS rejuvenation research programs. This sort of thing is a sign of progress, a point at which newcomers turn up out of the blue and pitch in with no prompting required. The team is in the early stages of assessing bacterial species for their ability to break down 7-ketocholesterol, a form of metabolic waste important in aging. Cells struggle to degrade this and similar forms of oxidized lipids, and a faster progression of atherosclerosis is one of the numerous consequences. The next step for the team is to identify the specific enzymes employed by promising bacterial species, and assess them for potential use as the basis for a therapy.

Intrinsic insufficiencies in cellular catabolism and transport, particularly in post-mitotic and senile cells, lead to the build up of specific compounds that exert deleterious effects on cellular function and viability. One example of accumulation of pathogenic compounds is the formation of transformed oxysterols that exhibit cytotoxicity towards mammalian cells and are shown to participate in the pathogenesis of several age-related diseases. The major intracellular cholesterol oxide, 7-ketocholesterol, has been involved in pathogenesis of age-related diseases such as atherosclerosis, Alzheimer's disease, Parkinson's disease, and cancer. This compound is a natural oxysterol produced via autooxidation of cholesterol and cholesterol-fatty acid esters and mainly found in oxidized lipoprotein deposits associated with atheromatous plaques.

Therefore, the delivery of microbial sterol-catabolizing enzymes into affected cell types may be advantageous for controlling elevated 7-ketocholesterol levels, and consequently help to reduce the severity of the diseases associated with the accumulation of this oxysterol. Several human enzymes are capable of metabolizing 7-ketocholesterol, but the main limitation is their localization in cellular compartments other than the lysosomes that makes them not very efficient at preventing lysosomal membrane permeabilization as well as resulting death-signalling cascade. The goal of this study was to isolate the microorganisms with high catabolic activity towards 7-ketocholesterol from diverse environmental samples (sea water sediment, soil, manure piles).

Four bacterial isolates, showing high catabolic activity towards 7-ketocholesterol were isolated: Alcanivorax jadensis IP4 (sea water sediment), Streptomyces auratus IP2 (soil), Serratia marcescens IP3 (soil) and Thermobifida fusca IP1 (manure piles). All the isolates were capable of utilizing 7-ketocholesterol as the sole organic substrate, resulting in its mineralisation. Overall, these results support the notion that oxysterol levels might be controlled by biodegradation processes, and further investigation of specific microbial enzymes involved in catabolism as well as the specific pathways involved in microbial 7-ketocholesterol degradation can be the next goals leading to come up with identifying enzymes capable of transforming oxysterols for potential environmental, industrial, pharmaceutical, and medical applications.


Methuselah Fund Closes Initial Fundraising, Reports on Some Early Investments

I'm pleased to note that the Methuselah Fund has closed its first fundraising effort after hitting the target amount, obtaining the support of many long-standing members of our community. The fund is a mixed for-profit/non-profit vehicle that is intended to expand the investment efforts undertaken by the Methuselah Foundation in past years, helping promising lines of rejuvenation research to make the leap from laboratory to commercial development. At the present point in time there are few enough rejuvenation focused companies that doing this well requires extensive connections within the research community, and a willingness to step in and help specific teams and lines of work to crystallize into startup companies sooner than might otherwise have been the case. Traditional venture capital tends to do more sitting on the sidelines, waiting for opportunities to arise. That works, more or less, in a more mature field, but not here, not yet.

Given the rise of senolytics startups and the notable financial success of Unity Biotechnology, an increasing number of venture funds are starting to pay attention and take the treatment of aging seriously. Their principals should take notes regarding the the activities of the highly connected early participants - such as the Methuselah Fund, Longevity Fund, Kizoo Technology Ventures, and so forth - as following the standard biotechnology venture playbook probably won't work all that well for another few years at least. This is a field in the early stages of a sweeping transition and what will ultimately be enormous growth, in which one really has to dive in and get to know the researchers and research programs. Success comes from reaching into academia and helping companies to form; backing specific models of intervention and specific researchers, not the offerings of specific companies and entrepreneurs.

The Methuselah Foundation successfully closes its boutique venture fund, the Methuselah Fund, focused on companies that can extend the healthy human lifespan.

The Methuselah Foundation, promoting the extension of the healthy human lifespan for 17 years, announces the successful closing of fundraising for its boutique venture fund, Methuselah Funds LLC (M Fund). The M Fund is mission-oriented and focused on seed-stage companies that have technology to increase the healthy human lifespan in multiple ways. The investment thesis of the M Fund is based around six pathfinding strategies that provide a structure to how the Fund believes healthy longevity can be achieved. These strategies have been purposefully named in a non-academic way in order to explain the thought process via analogies and recognizable ideas. These strategies and the details are:

1) New Parts for People - As we age, the wear and tear we put on our bodies begins to take a toll. As one body component begins to weaken, this leads to an exponential strain on the body that stresses remaining parts, leading to failure and eventual death. This strategy focuses on technologies that create replacement parts of our bodies, such as organs, cartilage, bones, and vasculature.

2) Get the Crud Out - Cellular processes of life result in by-products that are harmful if not cleared by the cell. As we age, there is an increasing amount of DNA damage and accumulation of wastes, which negatively affect cellular and organ function. This strategy focuses on technologies that clear harmful substances from the body at both the microscopic (cellular), and macroscopic (organ) level.

3) Restore the Rivers - As an individual ages, the vascular system becomes less effective due to vessel stiffening, less effective pumping, insufficient waste clearance, poor oxygen exchange, and inadequate angiogenesis. This affects every process of the body, down to the sub-cellular level. This strategy addresses the need to restore the circulatory system to youthful competence.

4) Debug the Code - The code includes DNA, and also the "action code", RNA, and proteins that actually do the work of the cells, which become damaged and altered with age. This strategy deals with the informational life of the cell and its expression.

5) Restock the Shelves - As we age, stem cells become fewer and less effective, senescent cells become more prolific, and the immune system becomes weakened. This strategy addresses the need to provide the aged body with the tools required to rebuild and protect itself.

6) Lust for Life - Among the aged, depression, loss of purpose, loss of senses, loss of independence, and social isolation are serious problems. This strategy addresses the need to help elderly patients want to increase their longevity, and to empower them to make the most of longer life.

The M Fund was conceived after successful angel mission-focused investments by the Methuselah Foundation. These include being the lead investor in the seed-stage round of Organovo Holdings, Inc, a medical laboratory and research company which designs and develops functional, three-dimensional human tissue for medical research and therapeutic applications. Investment in the longevity field is heating up significantly and the M Fund anticipates that investments will begin pouring into the area over the next 18 months. The M Fund's current portfolio companies include:

OncoSenX - A pre-clinical cancer company that targets solid tumors based on transcriptional activity using a unique lipid nanoparticle and plasmid DNA. OncoSenX is working on the next generation in cancer therapy that will be more targeted and with fewer side effects. Their treatment delivers a simple program that induces apoptosis in cancerous cells.

Leucadia - Has a unique and compelling approach on how to potentially predict, halt, and cure early stage Alzheimer's disease. 25 years of research have focused on plaques and tangles as the cause of AD. At Leucadia, it is known that those are previously undiscovered pathological effects of a more serious underlying condition. Leucadia's technology may allow for the creation of a simple, yet sophisticated surgical procedure bypassing the unsuccessful small-molecule approach.

Oisin - Their research and platform technology demonstrate that one of the solutions to mitigating the effects of age-related diseases is to address the damage resulting from the aging process itself. Oisín is developing a highly precise, DNA-targeting platform to clear senescent cells. Oisín's platform has shown as much as an 80% reduction in senescent cells in cell culture and significant reductions of senescent cell burden in naturally aged mice.

Revercell - Is developing global and transformational epigenetic solutions, moving past the single gene/pathway manipulations of traditional approaches, to address the multifaceted manifestation of cellular age, with tissue and organ level benefit. The company is developing the technology to effectively turn mature differentiated cells to a dramatically younger state, without first turning them into totipotent or pluripotent cells.

A Possible Role for Sirtuin 7 in Osteoporosis

Researchers recently provided evidence to suggest that sirtuin 7 is involved in the imbalance between bone creation and and bone destruction that arises in old age, leading to osteoporosis. The extracellular matrix of bone tissue is constantly remodeled, with osteoclast cells breaking it down and osteoblast cells building it up. In older people the activity of osteoclasts begins to outweigh the activity of osteoblasts, weakening bones. There are many possible contributing causes, from the effects of inflammation on the generation of these cells to altered signaling environments in aged tissue affecting the pace at which the cells undertake work. Overall it has the look of a condition in which the proximate cellular cause of imbalanced bone remodeling is a fair way downstream from the roots of aging.

Bone is a living tissue that is repeatedly broken down (bone resorption) and remade (bone formation) little by little every day. If this balance collapses and bone resorption exceeds bone formation, bone density decreases and can lead to osteoporosis. Sirtuins are enzymes that play important roles in controlling aging, stress responses, various areas of the metabolism, and several other body functions. In mammals, there are seven types of sirtuins, SIRT1 to SIRT7. Although SIRT7 has been reported to be involved in cancer and lipid metabolism, its role in bone tissue and bone aging was unknown.

Recent experiments showed that mice lacking the SIRT7 gene had reduced bone mass. Analysis showed that bone formation and the number of osteoblasts (bone-building cells) had been reduced. Furthermore, the researchers obtained similar results using osteoblast-specific SIRT7 deficient mice, thereby showing that osteoblast-specific SIRT7 is important for bone formation. To clarify the mechanism, the researchers compared sirtuin (SIRT1, 6, and 7) expression in the skeletal tissue of young and old mice, and found that SIRT7 decreased with age. Additionally, the expression of genes indicating osteoblast differentiation was also decreased, thereby revealing that SIRT7 controls the differentiation of osteoblasts.

Researchers found that the transcription activity of SP7 (also known as Osterix), a protein known to induce differentiation of pre-osteoblasts into mature osteoblasts and osteocytes, was markedly decreased in osteoblasts that lacked the SIRT7 gene. "In situations where SIRT7 does not work sufficiently, such as in an older individual, osteoblast formation is impaired due to low SP7/Osterix transcriptional activity. We believe that this decreased osteogenesis is associated with osteoporosis. Our results show that the regulatory pathway of SIRT7 - SP7 / Osterix is a promising target for new therapeutic agents to treat decreased osteogenesis and osteoporosis."


Daily Low Dose Aspirin Fails to Extend Healthy Life Spans in Older Patients

Aspirin is arguably a calorie restriction mimetic, able to spur some of the same beneficial cellular stress responses that are activated by low nutrient levels. Calorie restriction itself, practiced over the long term, does not have a very large effect on human life span. Given the existing demographic data, a gain of even five years of life would be very surprising. Further, it is well established that the life extension resulting from calorie restriction scales down as species life span scales up. Mice live up to 40% longer on calorie restricted diets, but we humans certainly don't.

Aspirin has other effects besides increasing cellular stress responses, some good and some bad. Either no effect, a very small reduction, or a very small gain in life span are all plausible predictions for the outcome of a study on use of aspirin in older patients. The initial results from this study of aspirin cannot be used to discuss overall life span, but the data does show no gain in a common measure of healthy life span, free from disability. Nonetheless, this is a result that can be compared to studies in short-lived species in which it does modestly extend healthy life. This is more or less exactly what we should expect to see from most of the current crop of calorie restriction mimetic drugs. It would be surprising to see large effects on life span in humans, given what is known of the underlying mechanisms, and given that most of these compounds are only mildly mimetic of the actual calorie restriction response.

The large ASPirin in Reducing Events in the Elderly (ASPREE) trial is intended to determine the risks and benefits of daily low-dose aspirin in healthy older adults without previous cardiovascular events. Initial results show that aspirin did not prolong healthy, independent living (life free of dementia or persistent physical disability). Risk of dying from a range of causes, including cancer and heart disease, varied and will require further analysis and additional follow-up of study participants.

ASPREE is an international, randomized, double-blind, placebo-controlled trial that enrolled 19,114 older people (16,703 in Australia and 2,411 in the United States). The study began in 2010 and enrolled participants aged 70 and older; 65 was the minimum age of entry for African-American and Hispanic individuals in the United States because of their higher risk for dementia and cardiovascular disease. At study enrollment, ASPREE participants could not have dementia or a physical disability and had to be free of medical conditions requiring aspirin use. They were followed for an average of 4.7 years to determine outcomes.

In the total study population, treatment with 100 mg of low-dose aspirin per day did not affect survival free of dementia or disability. Among the people randomly assigned to take aspirin, 90.3 percent remained alive at the end of the treatment without persistent physical disability or dementia, compared with 90.5 percent of those taking a placebo. Rates of physical disability were similar, and rates of dementia were almost identical in both groups.

The group taking aspirin had an increased risk of death compared to the placebo group: 5.9 percent of participants taking aspirin and 5.2 percent taking placebo died during the study. This effect of aspirin has not been noted in previous studies; and caution is needed in interpreting this finding. The higher death rate in the aspirin-treated group was due primarily to a higher rate of cancer deaths. A small increase in new cancer cases was reported in the group taking aspirin but the difference could have been due to chance. As would be expected in an older adult population, cancer was a common cause of death, and 50 percent of the people who died in the trial had some type of cancer.

The researchers also analyzed the ASPREE results to determine whether cardiovascular events took place. They found that the rates for major cardiovascular events - including coronary heart disease, nonfatal heart attacks, and fatal and nonfatal ischemic stroke - were similar in the aspirin and the placebo groups. In the aspirin group, 448 people experienced cardiovascular events, compared with 474 people in the placebo group.


The Conservatism Inherent to Human Nature Strives to Kill Us All

All people are conservative, their first impulse being to preserve the status quo. There are few examples of day to day life that is so terrible it will not be defended against change. Near all change is resisted, viewed with suspicion, and rouses resentment against the effort of will and thought required. This is the case whether or not the change is positive. The greater the change, the more that people dig in their heels. These highly conservative urges are set deep within the core of the human condition, a part of the primate evolutionary heritage of hierarchy and state of mind.

Now consider that we are proposing to up-end everything to do with aging, to change everything in the trajectory of a life through the introduction of rejuvenation therapies. To change the view of parents and grandparents, to change relationships with all older people, to throw out all long term plans for the future and replace them with different ones. The result will be a world made enormously better, in the sense that the disease, suffering, and slow death of later life will diminish rapidly and eventually go away entirely. Yet people are genuinely slow to buy in to this vision: it is a struggle to discard an accepted, known certainty (even if it is of aging, pain, and death) in order to take on the unwanted effort of engaging with future change (even if it is an end to that aging, pain, and death). So people stick with what they know.

This is a deep and serious flaw in our species. Our inherent conservatism strives to kill us in this era of rapid progress in biotechnology, by encouraging us to reject the greatest and most beneficial applications of new life science technologies. It is possible to bring an end to aging in the decades ahead, but that will require the sort of massive funding and widespread support that attends efforts to treat cancer. It requires an acceptance that the new status quo - for now - is to live in a world that strives for healthy longevity, in which the future of a life has an uncertain and unbounded upside. Everything changes for the better, but all planning and assumptions must be reworked. This sweeping change in the public view of aging has yet to happen, and as a consequence funding for rejuvenation research remains anemic.

The Status Quo of Aging

One of the reasons why the idea of rejuvenating people isn't all that easy to sell is that it challenges the status quo. For good or bad, we're used to the fact that our health goes south on us as time goes by, ultimately killing us if nothing else does. That's not a nice certainty to have, but our species is one of planners; we tend to prefer bad certainties to uncertainty. For example, some people want to be certain that, at some point, they won't be fit for work anymore and will need to retire; they prefer this over the uncertainty of not knowing how they'd make a living at age 150.

That's not the only reason. Radical change requires radical rethinking of anything affected by the change itself; as rejuvenation would affect our social contracts, the job market, future planning, our idea of life milestones, of family, what it means to be old, and many other things, it would take a lot of rethinking - which is something humanity generally does only grudgingly and on its own sweet time.

Think about it: "Granny" is more likely to make you think of a sweet, gray-haired lady with large glasses on her nose baking a cake than of an attractive girl out one late night with friends. Yet, in a world in which comprehensive rejuvenation is common, the granny and grandpa that inhabit our collective imagination would simply not exist; rather, you'd find that grannies and grandpas in their late 80s can't be told apart from people in their 20s; elderly would look just as young as "truly young" people, would be just as healthy, and would be engaged in the activities they prefer rather than having their activities limited by their declining health.

This is only one example out of many more new situations that we, having grown up in a world plagued by aging, would have to get used to; newer generations born in a post-aging world would hardly have any problem with it and would probably end up wondering how anyone could possibly have opposed it in the past. Examples like this are different from concerns such as overpopulation in that they don't represent a potential but tangible issue that might arise as a consequence of rejuvenation; people may have problems with biologically young elderly people simply because they're new and unfamiliar ideas, not because they pose any actual problem.

The Chronic Inflammation of Aging Impairs Nerve Maintenance and Regeneration

Chronic inflammation arises in aging for a variety of reasons. Researchers focused on immune system dysfunction refer to inflammaging, a state in which the immune system is both roused and ineffective. This is in part a result of the burden of persistent infection gained across a lifetime, but also a consequence of growing numbers of senescent cells. The immune system should be removing these cells, but progressively fails at that task also. Thus immune system failure feeds upon itself, accelerating like all aspects of age-related decline. Damage causes damage.

A more subtle consequence of continual inflammation is disruption of the normal processes of tissue maintenance and regeneration. Brief and localized inflammatory signaling is a necessary part of the normal operation of regenerative processes in youthful tissues, helping to guide the intricate interactions between stem cells, immune cells, and somatic cells that is required to rebuild and repair tissue structures. Constant inflammation runs roughshod over the delicate relationships at the heart of regeneration.

The regenerative capacity of peripheral nerves declines during aging, contributing to the development of neuropathies, limiting organism function. Changes in Schwann cells prompt failures in instructing maintenance and regeneration of aging nerves; molecular mechanisms of which have yet to be delineated. Here, we identified an altered inflammatory environment leading to a defective Schwann cell response, as an underlying mechanism of impaired nerve regeneration during aging.

Chronic inflammation was detected in intact uninjured old nerves, characterized by increased macrophage infiltration and raised levels of monocyte chemoattractant protein 1 (MCP1) and CC chemokine ligand 11 (CCL11). Schwann cells in the old nerves appeared partially dedifferentiated, accompanied by an activated repair program independent of injury. Upon sciatic nerve injury, an initial delayed immune response was followed by a persistent hyperinflammatory state accompanied by a diminished repair process. As a contributing factor to nerve aging, we showed that CCL11 interfered with Schwann cell differentiation in vitro and in vivo.

Our results indicate that increased infiltration of macrophages and inflammatory signals diminish regenerative capacity of aging nerves by altering Schwann cell behavior. The study identifies CCL11 as a promising target for anti-inflammatory therapies aiming to improve nerve regeneration in old age.


Linking Altered Signaling to Splicing Factors and Cellular Senescence in Aging

Alterations in the levels and behaviors of splicing factors have gained more attention of late in the study of aging, particularly in the context of the increased numbers of senescent cells present in aged tissues. Researchers here report on an exploration of some of the connections that exist between splicing factors, cellular senescence, and a number of proteins already known to undergo age-associated changes in their gene expression.

Aging is at root the consequence of numerous forms of molecular damage, but every tissue is a dynamic system in which any given change leads to countless chains of consequences: altered signaling, altered mechanisms, a complex dance of interlocking feedback loops. Tracing these paths is an enormous task, and building a full map is far beyond the present capacity of the research community. It will require decades to make even modest inroads into thin slices of cellular biochemistry - just look at the history of sirtuin research for an example of such a lengthy and narrowly focused research effort.

Waiting for full understanding before taking action is not the right strategy in the matter of aging. We do not have the luxury of time. Given that the molecular damage that causes aging has been identified with a high degree of confidence, the right path is to repair this damage and then see whether benefits result. As efforts related to the selective destruction of senescent cells have demonstrated in recent years, the beneficial outcomes will be very clear and the effect sizes large and reliable if the target is in fact a significant cause of aging.

A study has found that certain genes and pathways that regulate splicing factors - a group of proteins in our body that tell our genes how to behave - play a key role in the ageing process. Significantly, the team found that disrupting these genetic processes could reverse signs of ageing in cells. Aged, or senescent, cells are thought to represent a driver of the ageing process and other groups have shown that if such cells are removed in animal models, many features of ageing can be corrected. This new work found that stopping the activity of the pathways ERK and AKT, which communicate signals from outside the cell to the genes, reduced the number of senescent cells in in cultures grown in the laboratory. Furthermore, they found the same effects from knocking out the activity of just two genes controlled by these pathways - FOXO1 and ETV6.

The ERK and AKT pathways are repeatedly activated throughout life, through aspects of ageing including DNA damage and the chronic inflammation of ageing. The research suggests that this activation may hinder the activity of splicing factors that tell genes how to behave. This, in turn, could lead to a build-up of senescent cells - those which have deteriorated or stopped dividing as they age. To stop the activity of the ERK and AKT pathways, the study used inhibitors which are already used as cancer drugs in clinics. When the pathways were disrupted, the team observed an increase in splicing factors, meaning better communication between protein and genes. They also noted a reduction in the number of senescent cells. Researchers saw a reversal of many of the features of senescent cells that have been linked to the ageing process.


A View of Advanced Glycation End-Products that is Primarily Inflammatory

In the materials noted here, a Buck Institute researcher puts forward a view of just one side of the science of advanced glycation end-products (AGEs) and their role in degenerative aging. AGEs are sugary metabolic byproducts of many different varieties, both present in the diet and generated in the body. In the view of AGEs and aging expounded here, near all of the many types of AGE are important, most are transient and levels will vary in response to day to day circumstances, dietary intake of AGEs probably has a significant negative influence on long-term health, and AGEs present in tissues disrupt metabolism by hammering on a set of receptors that trigger chronic inflammatory signaling and a range of other inappropriate cellular behavior.

This leads to proposals for interventions that run along the lines of eating a better diet, finding ways to block the interaction between AGEs and receptors such as RAGE and RANKL, and so forth. If successful, these approaches could be expected to slightly slow the pace of aging, largely via reduced levels of chronic inflammation. It isn't an unreasonable viewpoint: the evidence for AGEs to cause inflammation is fairly robust; the involvement of RAGE is well demonstrated; inflammation does indeed accelerate the progression of all of the common age-related diseases. The question of whether or not dietary intake of AGEs is important in comparison to the creation of AGEs in the body can be debated. It is hard to separate this one potentially negative contribution to health from the many others associated with the sort of sugary, fatty diet that is high in AGEs.

All of this, however, is just the one side of considerations of AGEs and aging. In the materials here there is no mention of the other side, which is that in humans, the overwhelming majority of persistent cross-links formed by AGEs involve glucosepane rather than any of the other varieties of AGE. So when it comes to damage to the material properties of the extracellular matrix, leading to structural change in skin and blood vessels due to loss of elasticity, or structural change in bone and cartilage due to loss of tensile strength, only one type of AGE really counts. In this view of AGEs and aging, the vast majority of short-lived AGEs ebb and flow, while age-related degeneration is driven by the glucosepane AGEs that persist to shackle molecules of the extracellular matrix to one another, weakening and stiffening tissues.

A key challenge in this area of research is that the important classes of persistent AGEs and cross-links are completely different between mammalian species, and hence (a) past attempts to remove cross-links failed to translate from mice to humans, while (b) the ability to work with glucosepane at all was only developed comparatively recently, as this compound isn't a focus for groups working primarily in mice, and (c) ongoing work on AGEs in short-lived species is of little relevance to cross-links and aging in humans. That said, give it another five to ten years or so and I'd imagine we'll have solid evidence to back a declaration regarding which of these views of AGEs is the more important in aging. Glucosepane cross-link breaker development at the Spiegel Lab and elsewhere has been nearing the leap from laboratory to startup company for a few years now. If the Buck Institute is signaling interest in the other side of the AGE field, then approaches on that side of the house may also start to emerge in the near future.

Advanced Glycation End Products As Drivers of Age-Related Disease

An inevitable by-product of metabolism, advanced glycation end products (AGEs) are toxic molecules formed when proteins, DNA, and fats become bound after exposure to sugar. They are also in some of the foods we eat. Some Buck Institute researchers think the research community has neglected the importance of AGEs because they are challenging to study. Now they are on a mission to get scientists to focus on them as a driver of many age-related diseases. AGEs affect nearly every cell type and our bodies have inherent defense mechanisms that can clear them. But the production of AGEs really ramps up when blood sugar is high, and eating a typical high-carbohydrate, highly processed Western diet can overwhelm those natural defenses. Further, some of us are likely to be genetically prone to develop more of them, no matter what we eat.

AGEs make our cells old before their time, and over time the molecules accumulate in our tissues. The AGEs cause chronic inflammation, make proteins lose their shape, and send our metabolism into a sugar burning state, making it hard to lose weight. To make matters worse, the molecular damage from AGEs is irreversible. AGEs contribute to obesity and metabolic syndrome. They've long been implicated in insulin-resistant type 2 diabetes and are linked to its complications. In addition, AGEs are now seen as potential players in neurodegeneration. Recent findings associate AGEs with familial, early-onset and sporadic forms of Parkinson's disease, and with proteins linked to Alzheimer's disease. In one study, plaques extracted (post-mortem) from brains of patients with Alzheimer's show a 3-fold increase in AGEs content compared to age-matched individuals who died from other causes. AGEs are even found in cataracts.

The chemistry behind the formation of AGES was discovered in 1912 and an AGEs-based theory of aging was proposed more than three decades ago. Interest in the then red-hot field flagged when a drug designed to clear AGEs in diabetic kidney disease failed in clinical trials in 1998. But it's nearly impossible to study the biological development of AGEs and their implications in humans because they take decades to accumulate and there are obvious ethical concerns in encouraging the development of the toxic molecules in test subjects. So how to get researchers excited about understanding and exploiting the biology of AGEs?

The Buck Impact Circle, a donor group that pools its resources to support collaborative early-stage research at the Institute, has chosen to fund many projects involving AGEs. In addition to supporting research on the complications of diabetes and the link between AGEs and Parkinson's disease, the group has also funded projects aimed at determining if a ketogenic diet can protect against the complications of diabetes. This year they put their money toward research that tests compounds that show promise in lowering AGES associated with Alzheimer's disease pathology.

The Role of Advanced Glycation End Products in Aging and Metabolic Diseases: Bridging Association and Causality

Accumulation of advanced glycation end products (AGEs) on nucleotides, lipids, and peptides/proteins are an inevitable component of the aging process in all eukaryotic organisms, including humans. To date, a substantial body of evidence shows that AGEs and their functionally compromised adducts are linked to and perhaps responsible for changes seen during aging and for the development of many age-related morbidities. However, much remains to be learned about the biology of AGE formation, causal nature of these associations, and whether new interventions might be developed that will prevent or reduce the negative impact of AGEs-related damage. To facilitate achieving these latter ends, we show how invertebrate models, notably Drosophila melanogaster and Caenorhabditis elegans, can be used to explore AGE-related pathways in depth and to identify and assess drugs that will mitigate against the detrimental effects of AGE-adduct development.

An Update from the CellAge Team

The Life Extension Advocacy Foundation staff note a recent update from the CellAge team. That company was partially funded by a crowdfunding event, held at, that completed in early 2017. The founders are now moving forward with their work on synthetic promoters as a way to identify senescent cells and quantify the burden of senescence in specific tissues. The senolytics development community has spent the past few years forging ahead with ways to destroy senescent cells, but improvements in the state of assays for senescence has lagged behind.

Staining a tissue sample for simple markers of senescence, such as expression of p16, is the present standard procedure. It is good enough for development, but really not acceptable for either commercial use or more sophisticated research in the years ahead. If someone wants to assess on a month to month or year to year basis just how many senescent cells are in specific tissues, a much better approach will be needed. That demand will arise rapidly enough once human data starts to arrive from trials of early senolytic therapies. The microfluidics approach to counting senescent cells by size that was published last year is a step in the right direction, and hopefully the CellAge work will in the fullness of time lead to still better options.

We have been quiet for a while so we thought it was time for a small update about the Cellage project. We are working with Circularis to screen for new senescent cell promoters using a unique technological platform never used before with human or senescent cells. A promoter is a region of DNA that initiates the expression of a particular gene. Promoters are located near the transcription start sites of genes, on the same strand and upstream on the DNA. In this case, we are searching for gene expression relating to cellular senescence and using p16 and CMV promoters as our positive controls.

If this is successful we will then move onto screening for synthetic promoters from a library of over 100,000 novel synthetic promoters. The objective being to identify suitable promoters so we can develop a highly accurate way to detect the presence of senescent cells that surpasses the current state of the art methods such as p16.


Exosomes from Young Mice are Shown to Reverse Changes in Expression of Aging-Associated Genes in Old Mice

Work on heterochronic parabiosis, in which an old and young mouse have their circulatory systems joined, has led to a wide variety of investigations into which signal molecules present in the bloodstream might be important in aging. The signaling environment changes in response to rising levels of molecular damage with age, leading to alterations in cellular behavior, some of which help to compensate, and some of which cause further harm.

At the same time, there is a rising level of interest in the roles played by various forms of extracellular vesicle in intracellular communication. These membrane-wrapped packages contain a diverse set of signal molecules, and are passed promiscuously back and forth between cells. That vesicles are conveniently packaged and distinguishable by size makes it comparatively easy to harvest them from cell cultures or blood samples, and from there they can be analyzed, or perhaps used as the basis for a therapy to change the behavior of cells in old tissues.

Changing the signaling environment may produce benefits large enough to be worth chasing, as the stem cell research community has demonstrated over the past twenty years. Most first generation cell therapies work because of the signals generated by transplanted cells, not because the cells manage to survive and integrate into tissue. Unfortunately, this approach doesn't target the underlying damage that causes aging, and thus will always be limited as to how great the benefits can be at the end of the day. If the molecular damage of aging remains unrepaired, it will continue to cause pathology.

Understanding the regulatory mechanisms and the involved molecules underlying aging has aroused interest to prevent or delay aging or aging-associated diseases. It has been reported that the upregulated or downregulated miRNAs induce cellular senescence. In cell-to-cell signaling in systemic aging, miRNAs are reported to be released in circulation and transferred to remote tissues. The released miRNAs can affect their levels in circulation in aged individuals, and in a recent study, they served as regulatory molecules to control aging speed. Therefore, they are strongly considered as aging-associated biomarkers, possibly determined by minimally invasive or noninvasive methods. So far, several studies comparing miRNA expression profiles from the blood of young and old animals have revealed differences in the expression levels of several miRNAs with aging.

One of the ways by which miRNAs are released in circulation is via vesicles blebbed out from cellular membranes. A representative type of these vesicles is exosomes, which are tens to hundreds of nanometers in diameter. The exosomes released from parent cells enter systemic circulation, which thus explains the signaling process among remote tissues. Cells under stress would release more exosomes in vitro to dispose unnecessary molecules or communicate their signals to the surrounding cells. Actually, aging is a type of cellular stress; thus, exosomes are secreted at higher levels from senescent cells than from normal cells. However, limited information is available on changes in the miRNA contents of exosomes in naturally aged individuals and their effects in the aging process. Therefore, the identification of miRNA molecules deregulated in exosomes in the aging process would be required to understand the mechanisms underlying aging and may have potential applications in evaluating or reversing the aging status of an individual.

In this study, we primarily identified differentially expressed miRNAs in exosomes from aged mice and compared them with those from young mice. If the miRNAs in exosomes have regulatory capability in systemic aging, their increased levels in young exosomes were expected to exert a reversing effect on tissues of old mice. Therefore, after intravenously injecting exosomes from young mice to aged mice, changes in aging-associated molecule levels were analyzed in aged mice. In the aged tissues injected with young exosomes, mmu-miR-126b-5p levels were reversed in the lungs and liver. Expression changes in aging-associated molecules in young exosome-injected mice were obvious: p16Ink4A, mTOR, and IGF1R were significantly downregulated in the lungs and/or liver of old mice. In addition, telomerase-related genes such as Men1, Mre11a, Tep1, Terf2, Tert, and Tnks were significantly upregulated in the liver of old mice after injection of young exosomes. These results indicate that exosomes from young mice could reverse the expression pattern of aging-associated molecules in aged mice. Eventually, exosomes may be used as a novel approach for the treatment and diagnosis of aging animals.


Tau Aggregation in the Aging Brain Disrupts Nuclear Pores, Possibly Explaining Loss of Function in Alzheimer's Disease

As the amyloid cascade hypothesis of Alzheimer's disease has it, the condition begins with growing levels of amyloid-β in the brain. The amyloid forms solid deposits with a surrounding halo of harmful biochemistry, degrading the function of nearby cells. Perhaps this is caused by failing drainage of cerebrospinal fluid, perhaps by the innate immune response to persistent infections, perhaps by other mechanisms such as the age-related failure of the immune system to clear up molecular waste as aggressively as it should. The amyloid sets the stage for mild cognitive impairment and the later deposition of altered forms of tau protein into neurofibrillary tangles. It is the tau aggregation that is associated with the real damage of Alzheimer's disease: the inflammation, the major dysfunction, the death of neurons in large numbers.

How exactly is tau wreaking such havoc, however? This is an open question, still awaiting a definitive collection of evidence and consensus. There is the hope that, given a good answer to this question, some form of molecular sabotage could prove to be the basis for a therapy to rescue patients who are far along in the progression of Alzheimer's disease. This would be an alternative to the more mainstream strategy of building ways to clear tau from the brain, analogous to the existing lines of work on anti-amyloid immunotherapies. Could this work? I'm not sure, and my feeling is that it is unlikely to be more cost effective than attempts to remove tau aggregates. Finding and blocking any one mode of damage without removing the neurofibrillary tangles will still leave all of the other modes of damage - and there will always be more than one path to harm. Biochemistry is nothing if not exceedingly complex. This is, more generally, the usual objection to adjusting the state of a diseased metabolism rather than removing the cause of disease.

The research here reports on an association between nuclear pore dysfunction and tau aggregration, and this may prove to be a significant contribution to neuronal dysfunction in tauopathies such as Alzheimer's disease. It is interesting to consider that nuclear pores in neurons contain some of the longest-lived proteins in the body. The very same molecule, the same atoms in the same configuration, might accompany you throughout life from birth to death. There is some speculation regarding these and other extremely long lived proteins as the next frontier of longevity science, the challenge that arises after all of the SENS rejuvenation programs are somewhere near completion, and we can largely repair all of the common forms of damage that cause aging. How to deal with potentially damaged molecules deep within countless vital brain cells that our biochemistry will never replace if left to its own devices? Perhaps there will be good answers to that question sooner rather than later, but it is beyond current capabilities, if not beyond present vision.

Tau interferes with nuclear transport in Alzheimer's disease

Researchers have long known that tau accumulates in the brains of individuals with Alzheimer's disease (AD), a major component of AD's hallmark neurofibrillary tangles. Precisely how tau contributes to the disease has remained a mystery. Now scientists have found that the nuclear pore complex, which controls the transport of molecules into the cell nucleus, is defective in animal and human AD cells and that the defect is associated with tau aggregation inside neurons. In a cell, the nucleus is surrounded by a membrane separating contents inside the nucleus from everything else within the cell. The nucleus communicates with the cell through the protein-rich structures known as nuclear pores. Defects in these pores have been suggested in other causes of dementia, particularly frontotemporal dementia, and in amyotrophic lateral sclerosis (ALS).

The nuclear pore complex includes more than 400 different proteins. Researchers focused on one of the major structural proteins of the pore, Nup98. In the presence of tau, the Nup98 nuclear pores are not evenly spaced throughout the structure as expected. Instead, they were physically disrupted, fewer in number, and coalesced with each other. Nup98 seemed to leak or be mislocalized in the cytoplasm of AD brain cells rather than remaining in the nuclear pore. Whenever it was mislocalized, those same cells tended to have aggregates of tau. The team found that the more extreme the AD disease was while patients were alive, at autopsy they had worse pathology related to Nup98 mislocalization with tau. In mice models, when human tau was added to cultures of living rodent neurons, Nup98 was mislocalized in the cytoplasm and functional nuclear import was disrupted.

Tau Protein Disrupts Nucleocytoplasmic Transport in Alzheimer's Disease

Here, we show that phospho-tau-positive cells in human AD and tau transgenic mouse brains, as well as in cellular models of tau-related AD neuropathology, have an impaired nuclear transport. Indeed, we found that tau can interfere with nuclear pore complex (NPC) integrity in different ways. Tau directly interacts with the nucleoporin Nup98 in vitro, leads to cytoplasmic mislocalization of Nup98 in neurofibrillary tangles (NFTs) and in neurons with phospho-tau in vivo, and induces a disruption of the NPC distribution in the nuclear membrane.

Consequently, we observe failure of nuclear pore transport and diffusion-barrier properties, with changes in pore permeability to inert test molecules (dextrans) of various sizes, as well as alterations in active protein import and export, including Ran, an endogenous protein whose localization is known to be sensitive to NPC dysfunction. We further show that tau and Nup98 directly interact as assessed by co-immunoprecipitation from human AD brain tissue and surface plasmon resonance (SPR) of recombinant proteins. In addition, in vitro experiments show that Nup98 triggers tau aggregation and accelerates tau fibrilization and thereby possibly contributes to tau aggregation and tangle formation or stabilization in neuronal somata in AD and tauopathy brains.

In summary, we provide in vivo and in vitro evidence for a pathogenic model in which accumulation of tau in the somatodendritic compartment, as occurs in AD and tauopathies, increases the tau concentration in the perinuclear space and enables abnormal interaction of tau with Nups, which in turn leads to impairment in nuclear transport. These tau:Nup interactions may induce a pathological disruption of NPC function and contribute to tau-induced neurotoxicity. Targeting this pathway could provide a new therapeutic strategy for AD and similar neurodegenerative diseases.