FIGHT AGING! NEWSLETTER
January 19th 2015
Fight Aging! provides a weekly digest of news and commentary for thousands of subscribers interested in the latest longevity science: progress towards the medical control of aging in order to prevent age-related frailty, suffering, and disease, as well as improvements in the present understanding of what works and what doesn't work when it comes to extending healthy life. Expect to see summaries of recent advances in medical research, news from the scientific community, advocacy and fundraising initiatives to help speed work on the repair and reversal of aging, links to online resources, and much more.
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- Considering the Impact of Age-Related Conditions on the Effectiveness of Regenerative Medicine
- Immortality and Death, Not Necessarily in that Order
- Comparing the Damage Done by Inactivity and Obesity
- A Winter Update from the Methuselah Foundation
- Extending Healthy Life by Eliminating More Unfit Cells
- Latest Headlines from Fight Aging!
- Surveying Present Initiatives in Longevity Science
- mTOR and Contact Inhibition
- On Bat Exceptionalism
- Overexpression of EGL-27 Extends Life in Nematodes
- Tissue Engineering of a Section of Contracting Muscle
- Reviewing Age-Related Changes in the Neuromuscular Junction
- Cold Shock Proteins and Neurodegeneration
- Lifespan and Healthspan in Nematode Longevity Mutants
- Investigating Iron in Aging
- An Attempt to Compensate for Deficiencies in Stem Cells Derived from Heart Failure Patients
CONSIDERING THE IMPACT OF AGE-RELATED CONDITIONS ON THE EFFECTIVENESS OF REGENERATIVE MEDICINE
Most people would like to focus on the impact of regenerative medicine on age-related conditions, but there is every reason to suspect the existence of a negative impact in the other direction. These conditions may well have varied detrimental effects on the class of cell transplant therapies that are presently fairly widely available via medical tourism. Aging is a matter of cellular and molecular damage, but damage spirals out to cause systematic dysfunction that in turn leads to more and different forms of damage: it is an accelerating curve downwards towards frailty and death once it gets going in earnest. These later types of damage and system failure can certainly turn around and influence the progression of earlier root cause damage, and can also potentially interfere in efforts to fix that root cause. It is the same in every complex machine, and things can break in ways that actively hinder repair. It all depends on the details of course, but even though researchers can now very partially treat the attenuation of a few of the various important cell populations and loss of tissue maintenance via cell transplants, that doesn't mean there is a direct and unhindered path to the goal of ending this contribution to aging.
So far the data somewhat mixed on the degree to which cell transplant treatments work less well in the old than in the young. A number of studies suggest that old stem cells can work just as well as young ones, if given the same cues. Other studies suggest the opposite, and it may well be that outcomes can vary widely by cell type and by the methodologies used in the clinic. Many types of stem cell transplant are producing clear and measurable benefits, and are somewhat better than any of the other available treatment options, but others are struggling in the labs or trials to bring reliable benefits to older patients.
A while back I suggested that we should feel fairly good about the long term development of regenerative medicine and tissue engineering as it pertains to aging because near all of the potential profits in this industry involve treating age-related diseases. Therefore the research and development community is highly motivated to identify and fix all of the potential problems inherent in treating older people. At the core that essentially boils down to understanding why stem cell activity fails with age, and in enough detail to be able to safely reverse that process at least for the duration of a cell therapy, but there will be much more to than that. Cell therapies themselves are going to become far more broad than simply a matter of stem cells and transplants. Ultimately the goal is a sophisticated control over cellular behavior wherever those cells might be. Currently the tools and outcomes are very crude, but they will become much sharper in the years ahead.
Here is a consideration of some of the hurdles that might be presented by the existence of specific age-related diseases in a patient, considered distinctly from the underlying aging process. What to do when one part of the machinery is very much more broken in this particular machine? That line of thought seems useful, I think, all part of the nuts and bolts of making the next generation of therapies work reliably and well:
Is stem cell therapy less effective in older patients with chronic diseases?
A promising new therapeutic approach to treat a variety of diseases involves taking a patient's own cells, turning them into stem cells, and then deriving targeted cell types such as muscle or nerve cells to return to the patient to repair damaged tissues and organs. But the clinical effectiveness of these stem cells has only been modest, which may be due to the advanced age of the patients or the effects of chronic diseases such as diabetes and cardiovascular disease.
Autologous Stem Cell Therapy: How Aging and Chronic Diseases Affect Stem and Progenitor Cells
Cardiovascular diseases (CVD), particularly coronary artery disease (CAD), are the most frequent causes of mortality worldwide, and along with metabolic pathologies, especially diabetes mellitus type 2 (T2DM), they approach an epidemic status. An ongoing high frequency of CVD is caused both by the progressive aging of the population and an unhealthy lifestyle associated with risk factors such as obesity, hyperglycemia, hyperlipidemia, and arterial hypertension, which promote early development of atherosclerosis and progression of cardiovascular pathologies.
Aging is characterized by numerous morphological and functional changes within different tissues and organs. The elasticity of blood vessels declines with age along with an increase in their stiffness, which predetermines the progression of arterial hypertension. As people age, their adipose tissue mass increases, while their muscle volume decreases, leading to the development of insulin resistance, the most important pathogenic factor of T2DM. Aging is also associated with comorbidities, the simultaneous presence of two or more different diseases, often with chronic long-lasting progression. The most frequent age-associated comorbidities confounding each other are CAD and T2DM and obesity, arterial hypertension, and T2DM.
The target affected by the most CVD risk factors is the blood vessel wall. Endothelial dysfunction is considered to be the key pathogenic mechanism of angiopathies associated with CAD and T2DM. It should be noted that endothelial dysfunction develops as a result of the interaction of different risk factors, such as insulin resistance, hyperglycemia, and dyslipidemia. The long-term presence of these factors affects endothelial cells and promotes their apoptosis, which leads to the nitric oxide (NO) production failure. As a consequence, the vasodilatation and anti-aggregation functions of the endothelium are dysregulated along with its ability to inhibit smooth muscle cell proliferation. These factors potentiate atherosclerosis progression, forming the morphological basis of CAD.
Many types of stem/progenitor cells, including mesenchymal stem cells (MSCs), have already been used in clinical trials of cell therapy for ischemic pathologies, and their safety and feasibility have been demonstrated, but the clinical effectiveness of these protocols was relatively modest and could not corroborate the promising results of preclinical studies. One reason for the insufficient effectiveness of autologous cell therapy may be a lack of understanding about stem/progenitor cells properties in patients with CVD. Most data regarding the regenerative potential of these cells were obtained from cells derived from relatively healthy young donors. However, aging and disease itself may negatively affect stem/progenitor cells and their microenvironment, and impaired stem/progenitor cell functional properties may diminish the effectiveness of autologous cell therapy in aged patients with CAD and metabolic disorders. In this review, we analyze how aging and chronic diseases such as CAD and T2DM affect the properties of stem/progenitor cells.
IMMORTALITY AND DEATH, NOT NECESSARILY IN THAT ORDER
Over the decades to come we will become an immortal species. Immortality is a word somewhat degraded from its old absolute meanings, and now people tend to use it as a lazy shorthand for an end to degenerative aging and disease achieved through medical science, such that no-one will grow frail or die. In that sense immortality means a life expectancy of about a thousand years or so given today's accident rates, but there is no reason to expect those rates to stay the same. Imagine every science fiction technology that might possibly be developed over the next few centuries, all of which will be applied to reduce the risk of injury and accident in everyday life. That will happen. It won't stop there, of course. A life expectancy of millions of years, involving a transition to become something far larger and more resilient than the present human form, existing as a distributed machine entity that can shrug off local supernovae as a passing inconvenience - well, that also is on the cards. Someone alive today will do that or something similar: all it takes is for that person to live sufficiently far into the decades ahead to enter the time in which medical advances increase future life expectancy faster than aging eats it away.
The big deal in today's advocacy is to help determine whether it is plausible to talk about people in middle age reaching that upward curve of life expectancy versus today's newborns. That latter demographic are, I think, almost certainly going to benefit from a life no longer limited by aging. They have time to wait out half a century of technological development at today's breakneck pace. It seems unlikely that they will miss out. The point of advocacy is to speed up what is inevitable for the 2060s and make a reality for the 2030s, as that is by no means a sure thing. There are all too many examples in the past of technological innovators and early advances making their mark and setting out the foundations of their field, only for it to take decades for interest to grow to the point of widespread development and availability.
Immortality as a term is often used to mock people who aim to speed progress towards even modestly extended life spans, attained through advances in medicine. This is somewhat interesting given modern cultural relationships with death. We have become a society that hides the ugly reality of the end of life behind curtains. It is the thing not shown, not talked about. I was struck by this comment from a writer who attained some popularity a little while back:
Living Longer, Dying Differently
"We're seeing death in a new way. Instead of taking it for granted, the people I know see it as a personal catastrophe. I get emails from people who are actually surprised that someone has died. They regard it as an injustice. I understand their feelings, I get it, but this is a fairly new perspective on death. Nobody in the 1900s would have regarded death as a personal catastrophe. They would have mourned and might have been grief-stricken, but they saw death all around them."
This is another part of the strange puzzle that is the indifference and even hostility of the public at large towards efforts to treat aging as a disease and thus extend healthy life: (a) few people acknowledge death and aging in the same way as was the case in the past, (b) yet billions are spent on obviously fake ways to obscure the cosmetic consequences of aging, or to try to slow its progression, and (c) at the same time all sorts of accusations are thrown at those who are engaged in serious scientific work to actually slow or reverse aging, while (d) people are largely supportive of efforts to treat specific conditions that are caused by aging, such as cancer and Alzheimer's disease. I have always found this mix of views and opinions, often all held at the same time by a single individual, to be mystifying.
One of the ways in which people reject even the possibility of modest life extension is to talk about how bored they would be, and how terrible it is to be alive and bored versus dead. After ten years of following progress in longevity science and advocacy for longer healthy lives it remains unclear to me just how much of that is a matter of rolling out any old argument to justify a predetermined position of opposition, the pro-aging trance as Aubrey de Grey has it, versus it being an actual heartfelt belief in the endless dull grey doldrums that await should anyone dare set foot past their 120th year of life. Like many of the arguments against treating aging as a disease and extending healthy lives as far as possible as quickly as possible, it doesn't stand up to even a cursory logical examination. In all probability it is not meant to - that isn't the point.
Longer Lives and the Alleged Tedium of Immortality
Categorical desires are more significant desires. They are akin to life projects or plans. They are desires around which our self-worth is organised, e.g. the desire to write a great novel, raise happy and successful children, make important scientific discoveries, and so forth. Williams claims that the satisfaction of contingent desires, while important, is not really what makes life worth living. It is the satisfaction of categorical desires that does that. Since they are the focal point of what we do on a daily basis, it is their satisfaction that makes us want to live. Williams's worry is that there are only so many categorical desires that one self can pursue. In the course of an immortal life, you would end up pursuing and satisfying every achievable categorical desire. Eventually, you would have nothing left to make your life worth living. You would be bored, listless and tired of life.
Which all seems pretty silly to be concerned about to me. Boredom is a high class problem to have in comparison to pain, frailty, and the drawn-out death of everyone you care about. First things first: make the world a better place incrementally, and don't try to pretend that arm-waving about mental states in as yet hypothetical futures are in any way important in comparison to the prevention of suffering and death today.
COMPARING THE DAMAGE DONE BY INACTIVITY AND OBESITY
Looking over the day to day aspects of an ordinary life that an individual has control over, those with the greatest negative influence on long-term health are as follows: a diet that leads you to be overweight or obese for years, lack of regular exercise, and smoking. Studies suggest that these cause around the same level of harm, a loss of perhaps five years to a decade of life expectancy, and the addition of many more years spent in ill health rather than in good health. In the golden future ahead medicine will be capable of efficiently and effectively rescuing you from all the consequences of poor health practices, but we do not yet live in that future, and neglecting your health today reduces the odds of living to benefit from the impressive medical technologies of tomorrow.
There are of course strong correlations between diet, level of exercise, and excess weight, but that doesn't stop epidemiologists from peering deeply into the statistics of large population studies to try to pick apart the various contributions to shorter rather than than longer lives. This latest study of hundreds of thousands of people provides confirming evidence for a number of themes set out in past research. For example, it is fairly easy to establish sizable differences between the long term outcome for no exercise and the long term outcome for regular moderate exercise, but there is little to show that any greater benefits result from more exercise or different types of exercise. Obviously there are studies of elite athletes such as cyclists wherein these individuals live a decade longer than the rest of the population, but this is only correlation: are they long-lived because of the exercise, or is it instead because only the most robust individuals tend to become successful athletes? For everyone else there is no good study out there to say that twice as much exercise is twice as good. The big threshold is between none and some, and after that the data is increasingly nebulous.
Lack of exercise responsible for twice as many deaths as obesity
Physical inactivity has been consistently associated with an increased risk of early death, as well as being associated with a greater risk of diseases such as heart disease and cancer. Although it may also contribute to an increased body mass index (BMI) and obesity, the association with early death is independent of an individual's BMI. To measure the link between physical inactivity and premature death, and its interaction with obesity, researchers analysed data from 334,161 men and women across Europe participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study.
Using the most recent available data on deaths in Europe the researchers estimate that 337,000 of the 9.2 million deaths amongst European men and women were attributable to obesity (classed as a BMI greater than 30): however, double this number of deaths (676,000) could be attributed to physical inactivity. The researchers found that the greatest reduction in risk of premature death occurred in the comparison between inactive and moderately inactive groups. The authors estimate that doing exercise equivalent to just a 20 minute brisk walk each day - burning between 90 and 110 kcal ('calories') - would take an individual from the inactive to moderately inactive group and reduce their risk of premature death by between 16-30%. The impact was greatest amongst normal weight individuals, but even those with higher BMI saw a benefit.
Physical activity and all-cause mortality across levels of overall and abdominal adiposity in European men and women: the European Prospective Investigation into Cancer and Nutrition Study (EPIC)
The higher risk of death resulting from excess adiposity may be attenuated by physical activity (PA). However, the theoretical number of deaths reduced by eliminating physical inactivity compared with overall and abdominal obesity remains unclear. We examined whether overall and abdominal adiposity modified the association between PA and all-cause mortality and estimated the population attributable fraction (PAF) and the years of life gained for these exposures.
This was a cohort study in 334,161 European men and women. The mean follow-up time was 12.4 y, corresponding to 4,154,915 person-years. Height, weight, and waist circumference (WC) were measured in the clinic. Significant interactions (PA × BMI and PA × WC) were observed, so hazard ratios were estimated within BMI and WC strata. The hazards of all-cause mortality were reduced by 16-30% in moderately inactive individuals compared with those categorized as inactive in different strata of BMI and WC. Avoiding all inactivity would theoretically reduce all-cause mortality by 7.35%. Corresponding estimates for avoiding obesity (BMI of more than 30) were 3.66%.
The greatest reductions in mortality risk were observed between the 2 lowest activity groups across levels of general and abdominal adiposity, which suggests that efforts to encourage even small increases in activity in inactive individuals may be beneficial to public health.
The difference in projected mortality reductions from eliminating lack of exercise versus eliminating clinical obesity stems, I think, from the demographics: many more people live sedentary lives than are overweight to that level.
A WINTER UPDATE FROM THE METHUSELAH FOUNDATION
The Methuselah Foundation is one of the more important small non-profits involved in steering the near future course of aging research and human longevity. It is generally the case that the larger non-profits in medical research fund the status quo only, and so it is up to more nimble and driven organizations to make the status quo better - to really change the world, in other words. Organizations like the Methuselah Foundation and its core of dedicated supporters lead the way, change minds, and steer the broader community towards new and better directions more likely to extend healthy lives sooner rather than later.
It is worth remembering that, like the SENS Research Foundation, the Methuselah Foundation grew and established its presence due to the generosity of hundreds of donors of largely modest means. Their support helped to ensure the Foundation's important role in the sweeping changes that have taken place in the field of aging research and its goals over the past decade, shifting the leaders in the field towards open support for treating aging as a medical condition and the goal of extending healthy life spans. In the years since spinning off the SENS Research Foundation, the Methuselah Foundation has focused more on tissue engineering, but that is far from the only research activity funded and promoted by the Foundation staff.
A recent update on the activities of the Methuselah Foundation turned up in my in-box today, and I think many of you will be most interested to see that the Foundation is now funding a biotech startup effort to clear senescent cells and thus remove their contribution to degenerative aging. Senescent cell clearance is on my list as the most likely of the SENS repair-based technologies to be implemented first, even though funding is very limited for this area of research, as (a) there are a range of groups working on the problem or aspects of the problem, and (b) all of the various technologies needed to assemble a viable treatment either exist already or are very close to realization. It is good to see the Methuselah Foundation stepping in to support this field.
2014 was a year to remember. With a Methuselah Prize awarded to Dr. Huber Warner of the National Institute on Aging's Interventions Testing Program, the first six teams officially announced for the New Organ Liver Prize, and our first Organovo 3D printer awarded to the Yale School of Medicine, we've certainly been keeping busy.
Thanks to all of you, and especially to the passionate support of our many generous donors, we're also looking forward to an impactful 2015. We're still gathering more teams for the Liver Prize, exploring a possible New Organ Vasculature Challenge with federal agency partners, looking forward to the inaugural Organ Banking Summit in February, and much more.
We closed out last year by taking part in a successful fundraiser for the SENS Research Foundation, and we're ringing in the new one with a founding investment in Oisin Biotechnology. We also look forward to sharing more illuminating conversations with you from around the world of tissue engineering and regenerative medicine on our blog, "The Bristlecone."
Backing Oisin Biotechnology
The Methuselah Foundation has become a founding investor in Oisin Biotechnology, Inc, an early-stage company that aims to provide targeted biological solutions to degenerative aging conditions. We are also now represented on Oisin's Board of Directors. Initial research and development at Oisin will focus on controlled removal of senescent cells that underlie certain degenerative aging conditions. Both proprietary treatment protocols as well as proprietary methods for delivery of biologics to affected cells will be employed. Oisin is currently performing in vitro studies to confirm the expected mode of action of its therapy.
"We invested in Oisin," Methuselah CEO Dave Gobel explained, "because of the promise of their highly targeted approach to removing senescent cells without causing collateral damage or side effects. To put it more colloquially, I like to think of this as 'getting the crud out' - one of our key themes at Methuselah." We hope this founding investment will enable Oisin to establish proof of principle (does it work in vitro or not?). If it does work, we believe that Oisin will become extremely important in the field of longevity science - and provide us with a mission-aligned solution that is industrializable by harnessing infotech, biotech, and the body's own systems. We'll keep you posted.
New Federal Grant Program for Organ Cryobanking
We're excited to announce that the Organ Preservation Alliance, one of New Organ's partner organizations, has informed the development of three new federal grant programs by the Department of Defense targeting complex tissue and organ cryobanking for transplantation. These three unique but complimentary "Small Business Innovation Research" (SBIR) grants, the first of their kind, will launch on January 15, 2015. Together, they could fund research for 20 or more U.S. teams, with strong candidates potentially receiving $3-$3.5 million across phase one and phase two awards. Congratulations to the Organ Preservation Alliance for its critical role in this landmark moment for the undervalued field of cryopreservation.
Bowhead Whale Study Published
We've seen great news coverage recently of the bowhead whale research we funded at the University of Liverpool, and the full paper by Dr. Joao Pedro de Magelhaes and his team is being published in the journal Cell Reports. According to Magelhaes, "The bowhead whale is the longest-lived mammal, possibly capable of living over 200 years. Thanks to generous support from the Methuselah Foundation, we sequenced the bowhead genome and transcriptome and performed a comparative analysis with other cetaceans and mammals. We found that changes in bowhead genes related to cell cycle, DNA repair, cancer, and ageing could all be biologically relevant."
Exploring c60oo and Cancer Growth
Ichor Therapeutics, Inc., an exciting pre-clinical biotechnology company funded in part by Methuselah donors, is preparing to commence pilot studies to investigate the effects of c60oo administration on human cancer proliferation in vivo. It has been theorized that c60oo may be a potent inhibitor of primary tumor growth or metastasis. Data about human leukemia growth rates in the presence and absence of c60oo is expected to pave the way for additional studies of c60oo's effects on a variety of tumor models. "We are grateful to the Methuselah Foundation," Ichor CEO Kelsey Moody said recently, "for providing much of the necessary funding for this project, without which this important research could not be completed."
EXTENDING HEALTHY LIFE BY ELIMINATING MORE UNFIT CELLS
An intriguing open access paper was published earlier this week in which the authors made significant headway in understanding the details of a mechanism by which flies eliminate less functional cells on an ongoing basis. The researchers then manipulated this mechanism via gene therapy so that a greater proportion of these less fit cells were destroyed, and as a result the genetically altered flies lived longer. The effect on median life span is a 50-60% increase, and for maximum life span a more modest 10-20% gain:
Prolonging lifespan: Researchers create 'Methuselah fly' by selecting best cells
"Our bodies are composed of several trillion cells, and during aging those cells accumulate random errors due to stress or external insults, like UV-light from the sun." But those errors do not affect all cells at the same time and with the same intensity: "Because some cells are more affected than others, we reasoned that selecting the less affected cells and eliminating the damaged ones could be a good strategy to maintain tissue health and therefore delay aging and prolong lifespan."
To test their hypothesis, the researchers used Drosophila melanogaster flies. The first challenge was to find out which cells within the organs of Drosophila were healthier. The team identified a gene which was activated in less healthy cells. They called the gene ahuizotl (azot) after a mythological Aztec creature selectively targeting fishing boats to protect the fish population of lakes, because the function of the gene was also to selectively target less healthy or less fit cells to protect the integrity and health of the organs like the brain or the gut.
Normally, there are two copies of this gene in each cell. By inserting a third copy, the researchers were able to select better cells more efficiently. The consequences of this improved cell quality control mechanism were that the flies appeared to maintain tissue health better, aged slower and had longer lifespans. However, the potential of the results goes beyond creating Methuselah flies, the researchers say: Because the gene azot is conserved in humans, this opens the possibility that selecting the healthier or fitter cells within organs could in the future be used as an anti aging mechanism. For example, it could prevent neuro- and tissue degeneration produced in our bodies over time.
Elimination of Unfit Cells Maintains Tissue Health and Prolongs Lifespan
Individual cells can suffer insults that affect their normal functioning, a situation often aggravated by exposure to external damaging agents. A fraction of damaged cells will critically lose their ability to live, but a different subset of cells may be more difficult to identify and eliminate: viable but suboptimal cells that, if unnoticed, may adversely affect the whole organism. What is the evidence that viable but damaged cells accumulate within tissues? The theory is supported by the experimental finding that clonal mosaicism occurs at unexpectedly high frequency in human tissues as a function of time. Does the high prevalence of mosaicism in our tissues mean that it is impossible to recognize and eliminate cells with subtle mutations and that suboptimal cells are bound to accumulate within organs? Or, on the contrary, can animal bodies identify and get rid of unfit viable cells?
In Drosophila, cells can compare their fitness using different isoforms of the transmembrane protein Flower. The "fitness fingerprints" are therefore defined as combinations of Flower isoforms present at the cell membrane that reveal optimal or reduced fitness. The isoforms that indicate reduced fitness have been called FlowerLose isoforms, because they are expressed in cells marked to be eliminated by apoptosis called "Loser cells". However, the presence of FlowerLose isoforms at the cell membrane of a particular cell does not imply that the cell will be culled, because at least two other parameters are taken into account: (1) the levels of FlowerLose isoforms in neighboring cells: if neighboring cells have similar levels of Lose isoforms, no cell will be killed; (2) the levels of a secreted protein called Sparc, the homolog of the Sparc/Osteonectin protein family, which counteracts the action of the Lose isoforms.
Here, we aimed to clarify how cells integrate fitness information in order to identify and eliminate suboptimal cells. We find Azot expression in a wide range of "less fit" cells, such as WT cells challenged by the presence of "supercompetitors," slow proliferating cells confronted with normal proliferating cells, cells with mutations in several signaling pathways, or photoreceptor neurons forming incomplete ommatidia. In order to be expressed specifically in "less fit" cells, the transcriptional regulation of azot integrates fitness information from at least three levels: (1) the cell's own levels of FlowerLose isoforms, (2) the levels of Sparc, and (3) the levels of Lose isoforms in neighboring cells. Therefore, Azot ON/OFF regulation acts as a cell-fitness checkpoint deciding which viable cells are eliminated. We propose that by implementing a cell-fitness checkpoint, multicellular communities became more robust and less sensitive to several mutations that create viable but potentially harmful cells. Moreover, azot is not involved in other types of apoptosis, suggesting a dedicated function, and - given the evolutionary conservation of Azot - pointing to the existence of central cell selection pathways in multicellular animals.
We show that active elimination of unfit cells is required to maintain tissue health during development and adulthood. We identify a gene (azot), whose expression is confined to suboptimal or misspecified but morphologically normal and viable cells. When tissues become scattered with suboptimal cells, lack of azot increases morphological malformations and susceptibility to random mutations and accelerates age-dependent tissue degeneration. On the contrary, experimental stimulation of azot function is beneficial for tissue health and extends lifespan.
The paper makes for an interesting read, as it is the first I've heard of this line of research and the details of this particular quality control mechanism. I look forward to seeing the results of further studies conducted in mammals whenever they might take place: is the process in fact similar in higher animals such as mammals, and similarly open to beneficial manipulation? The gain in maximum life span here is on a par with that seen in lower animals as a result of boosting the operation of other, better known quality control systems, such as autophagy. There is probably going to be a sizable grey area in the future between the undesirable approach of "messing with metabolism" and the desirable approach of repair of damage as the two distinct possible strategies when building treatments for degenerative aging, and this result is a good illustration of the midpoint of that grey area, I think.
One possibility that occurred to me is that this may be a path towards putting some numbers to the degree to which we should expect stochastic nuclear DNA damage to be a significant contributing cause of degenerative aging. As you might know the consensus is that yes of course the random accumulation of this damage leads to less well regulated cells, and thus should be relevant to aging - and not just in the matter of cancer, but in the more general dysfunction of tissues. This is not a consensus without debate, however, and at present there are no good studies providing evidence to quantify the degree to which nuclear DNA damage contributes to aging. That might fall out of further study of azot, though I see that the categories of less fit cells quoted above include a wide range of states and situations that probably have no direct relationship with nuclear DNA damage.
LATEST HEADLINES FROM FIGHT AGING!
SURVEYING PRESENT INITIATIVES IN LONGEVITY SCIENCE
Monday, January 12, 2015
This popular press article takes a look at some of the present initiatives aimed at producing ways to treat aging and extend healthy life spans. The world at large is slowly coming to notice the position of the more forward-looking factions of the research community, which is that aging is just another medical condition and thus amenable to treatment:
In Palo Alto in the heart of Silicon Valley, hedge fund manager Joon Yun is doing a back-of-the-envelope calculation. According to US social security data, he says, the probability of a 25-year-old dying before their 26th birthday is 0.1%. If we could keep that risk constant throughout life instead of it rising due to age-related disease, the average person would - statistically speaking - live 1,000 years. Yun finds the prospect tantalising and even believable. Late last year he launched a $1m prize challenging scientists to "hack the code of life" and push human lifespan past its apparent maximum of about 120 years (the longest known/confirmed lifespan was 122 years).
Yun believes it is possible to "solve ageing" and get people to live, healthily, more or less indefinitely. His Palo Alto Longevity Prize, which 15 scientific teams have so far entered, will be awarded in the first instance for restoring vitality and extending lifespan in mice by 50%. But Yun has deep pockets and expects to put up more money for progressively greater feats. He says this is a moral rather than personal quest. Our lives and society are troubled by growing numbers of loved ones lost to age-related disease and suffering extended periods of decrepitude, which is costing economies. Yun has an impressive list of nearly 50 advisers, including scientists from some of America's top universities.
In September 2013 Google announced the creation of Calico, short for the California Life Company. Its mission is to reverse engineer the biology that controls lifespan and "devise interventions that enable people to lead longer and healthier lives". Though much mystery surrounds the new biotech company, it seems to be looking in part to develop age-defying drugs.
In an office not far from Google's headquarters in Mountain View, with a beard reaching almost to his navel, Aubrey de Grey is enjoying the new buzz about defeating ageing. For more than a decade, he has been on a crusade to inspire the world to embark on a scientific quest to eliminate ageing and extend healthy lifespan indefinitely (he is on the Palo Alto Longevity Prize board). It is a difficult job because he considers the world to be in a "pro-ageing trance", happy to accept that ageing is unavoidable, when the reality is that it's simply a "medical problem" that science can solve. Just as a vintage car can be kept in good condition indefinitely with periodic preventative maintenance, so there is no reason why, in principle, the same can't be true of the human body, thinks de Grey. We are, after all, biological machines, he says.
His claims about the possibilities (he has said the first person who will live to 1,000 years is probably already alive), and some unconventional and unproven ideas about the science behind ageing, have long made de Grey unpopular with mainstream academics studying ageing. (Even his critics say he funds some good science, however). But the appearance of Calico and others suggests the world might be coming around to his side, he says. "There is an increasing number of people realising that the concept of anti-ageing medicine that actually works is going to be the biggest industry that ever existed by some huge margin and that it just might be foreseeable."
MTOR AND CONTACT INHIBITION
Monday, January 12, 2015
Contact inhibition is a mechanism that suppresses cell division, halting the cell cycle in a densely packed cluster of cells. Much more efficient contact inhibition is presently a leading candidate for the reason why naked mole-rats do not suffer cancer: cancer creates dense masses of cells, and thus is halted at the outset in this species. There is considerable interest in the research community in finding ways to exploit this sort of mechanism, bringing it to humans as a therapy of some sort. Hence investigations are presently underway on a range of related mechanisms in cellular biology.
Here a researcher focused on the role of mTOR considers contact inhibition in that context, which spans cancer, cellular senescence, and numerous other aspects of aging. Of particular interest are the mechanisms determining the difference between reversible arrest of cell division, called quiescence, and irreversible arrest as occurs in cellular senescence:
Numerous studies have been aimed to pinpoint the difference between quiescence and senescence based on either the point of cell cycle arrest, the nature of stresses or peculiarities of Cyclin Dependent Kinase-inhibitor (CDKi)-induced arrest (p21 versus p16). Yet, despite all efforts, the distinction remained elusive. In fact, the difference between quiescence and senescence lies outside the cell cycle. A senescent program consists of two steps: cell cycle arrest and gerogenic conversion or geroconversion, for brevity. It is geroconversion that distinguishes quiescence from senescence. Geroconversion is "futile cellular growth" driven by mTOR as well as related mitogen-activated and growth-promoting signaling pathways. Rapamycin suppresses geroconversion, maintaining quiescence instead. Furthermore, any condition that directly or indirectly inhibits mTOR in turn suppresses geroconversion.
The two-step model is applicable to contact inhibition. Given that contact inhibition is reversible, we predicted that mTOR is inhibited. In fact, we found that mTORC1 targets are dephosphorylated in contact inhibited cells. Furthermore, activation of mTOR shifts reversible contact inhibition towards senescence. Thus, it is deactivation of mTOR that suppresses geroconversion in contact inhibited cells. Deactivation of mTOR was associated with induction of p27. In cancer cells, there is no induction of p27 in high cell density. Accordingly, cancer cells do not get arrested in confluent cultures.
There is a complex relationship between p27 and mTOR. It turned out that the mTOR pathway was inhibited in dense cultures of cancer cells. Yet, cancer cells do not induce p27 and do not undergo contact inhibition. mTOR is constitutively activated in cancer and induction of p21 by itself does not inhibit mTOR. So why mTOR is deactivated not only in contact-inhibited but also in confluent cancer cells? The answer is that cancer cells with highly increased metabolism rapidly exhaust and acidify the medium, thus inhibiting mTOR by starvation-like mechanism. In fact, change of the medium restored mTOR activity. Therefore, in normal cells with low metabolism, mTOR is deactivated by contact inhibition and the change of the medium only marginally affects mTOR. In cancer cells, mTOR is inhibited due to exhaustion of the medium. And some cell lines are somewhere in between.
ON BAT EXCEPTIONALISM
Tuesday, January 13, 2015
Comparative biology is a field gathering momentum these days. The tools of biotechnology have advanced to the point at which it is worth asking exactly how it is that some species are longer-lived, or more resistant to cancer, or capable of regenerating organ damage and lost limbs. It is especially useful to find similar species in which one is very different from the other in one of these aspects, as that gives a better chance of pinning down the important mechanisms. The end goal is better medicine: is there any possibility of deriving the basis for enhancements or therapies for humans from the longevity of whales, or the cancer immunity of naked mole-rats, or the regenerative prowess of salamanders? The answer will probably vary on a case by case basis: it is not unreasonable to expect that some aspects of biology in another species will be very hard to recreate in humans. The only way to find out is to make further progress in research.
Bats are on the list of exceptional species for many of the same reasons as those mentioned above, though not yet as well studied as naked mole-rats or salamanders. The evolution of flight has necessitated a set of unusual metabolic adaptations for a mammal, and as a result there are bats that are certainly unusually long-lived for their size, possibly cancer resistant, and so forth. This is an opportunity for researchers to learn more about how the operation of metabolism determines these outcomes:
The bat immune system is astonishingly tolerant of most pathogens. Evidence is mounting that bats can serve as reservoirs of many of the world's deadliest viruses, yet bats appear largely immune to the many viruses they carry and rarely show signs of the diseases that will rapidly overwhelm any human, monkey, horse, pig or other mammalian host the microbes manage to infiltrate. Scientists have also learned that bats live a seriously long time for creatures of their small size. The insectivorous Brandt's bat of Eurasia, for example, weighs an average of just six grams, compared with 20 grams for a mouse. But while a mouse is lucky to live for a year, the Brandt's bat can survive well into its 40s. Bats may be girded against cancer, too. "At this stage, the evidence is anecdotal. But of all the bat biologists I've spoken with, I've only heard of one or two cases of bat tumors."
Researchers found an "unexpected concentration" of genes involved in repairing damaged DNA. Those fix-it factors, the scientists proposed, are the bat's solution to the blistering demands of flight. When a bat flies, its heart beats an impressive 1,000 times a minute, and its metabolism ramps up 15-fold over resting rate. By contrast the metabolism of a running rodent is seven times normal, "and that's only for a short burst, whereas a bat can fly at 15-fold metabolic rate for hours." All that fiery flapping ends up generating a huge number of metabolic byproducts called free radicals, which could mutilate the bat's DNA were it not for its extra-strength molecular repair crew. And countering DNA damage happens to be a great strategy for overall health, which could explain bats' exceptional longevity and apparent resistance to cancer. Researchers suggest that changes to the bat's immune system originated as part of the heightened demand for DNA repair, and later proved valuable for its general life strategy.
OVEREXPRESSION OF EGL-27 EXTENDS LIFE IN NEMATODES
Tuesday, January 13, 2015
Many of the alterations found to extend life in lower animals like the nematode species Caenorhabditis elegans involve changes in the response to cellular stresses such as heat, starvation, and rising levels of oxidative damage due to cellular and other dysfunctions in aging. Stress response mechanisms such as increased cellular housekeeping and repair activities are important determinants of longevity in short-lived animals, but evolution has not optimized their operation for the longest possible life span. Thus a range of genetic changes can make these systems work more effectively from that perspective. Here is another example:
Stress is a fundamental aspect of aging, but it is unclear whether the molecular mechanisms underlying stress response become altered during normal aging and whether these alterations can affect the aging process. In this study, we found a GATA transcription factor called egl-27, whose targets are significantly enriched for age-dependent genes and stress response genes, and whose expression increases with age.
In contrast to previous work describing factors that are causal for aging, we found that egl-27 activity is likely beneficial for survival since egl-27 overexpression extends lifespan. egl-27 promotes longevity by enhancing stress response; specifically, increased levels of egl-27 protect animals against heat stress, while reduced egl-27 activity impairs survival following heat and oxidative stress. These results suggest that aging is not simply a process of constant decline. Some factors, such as egl-27, are more active in old animals, working to restore organismal function and to improve survival. Our work offers novel insight into the interplay between stress and aging, and suggests that aging is not simply a process of moving from an ideal young transcriptome to an inadequate old transcriptome. Rather, age-dependent changes in gene expression are likely comprised of a mix of beneficial, detrimental, and neutral changes.
TISSUE ENGINEERING OF A SECTION OF CONTRACTING MUSCLE
Wednesday, January 14, 2015
Researchers are making further progress towards fully functional muscle tissue grown from cells, though at this point the principal use for such engineered tissue is in research rather than treatment. Scaling up the size of the tissue produced remains a tough challenge due to the need to produce complex blood vessel networks within the engineered tissue. This is why techniques such as decellularization of a donor organ are making headway, as that provides a scaffold complete with a framework for blood vessels and the chemical cues needed to guide cells to repopulate them, something that cannot yet be produced from scratch:
Researchers started with a small sample of human cells that had already progressed beyond stem cells but hadn't yet become muscle tissue. They expanded these "myogenic precursors" by more than 1000-fold, and then put them into a supportive, 3D scaffolding filled with a nourishing gel that allowed them to form aligned and functioning muscle fibers. "We have a lot of experience making bioartifical muscles from animal cells in the laboratory, and it still took us a year of adjusting variables like cell and gel density and optimizing the culture matrix and media to make this work with human muscle cells."
Researchers subjected the new muscle to a barrage of tests to determine how closely it resembled native tissue inside a human body. They found that the muscles robustly contracted in response to electrical stimuli - a first for human muscle grown in a laboratory. They also showed that the signaling pathways allowing nerves to activate the muscle were intact and functional. To see if the muscle could be used as a proxy for medical tests, the researchers studied its response to a variety of drugs, including statins used to lower cholesterol and clenbuterol, a drug known to be used off-label as a performance enhancer for athletes. The effects of the drugs matched those seen in human patients. The statins had a dose-dependent response, causing abnormal fat accumulation at high concentrations. Clenbuterol showed a narrow beneficial window for increased contraction. Both of these effects have been documented in humans. Clenbuterol does not harm muscle tissue in rodents at those doses, showing the lab-grown muscle was giving a truly human response.
REVIEWING AGE-RELATED CHANGES IN THE NEUROMUSCULAR JUNCTION
Wednesday, January 14, 2015
Synapses of the neuromuscular junction (NMJ) connect nerves to muscles. Researchers have observed age-related detrimental changes in the NMJ and its ability to regenerate, though at this point it isn't completely clear how these alterations arise from underlying damage. Here is an open access review on this topic:
Autopsy studies in persons who died of acute trauma while relatively healthy have shown that aging is associated with a gradual loss of motor neurons. The mechanism that leads to neuronal loss with aging is still unclear and may involve both impaired trophic signaling from the central nervous system, local degeneration, and feedback from dysfunctional muscle.
Regardless of the cause, when a motor neuron is lost, fibers previously innervated by that neuron, globally defined as a motor unit, are no longer controlled by the nervous system and fail to contribute to the force generated during a volitional muscle contraction. In the attempt to counteract the functional consequence of this process, denervated orphan fibers express proteins and produce chemotactic signals that stimulate the sprouting of new dendrites from residual motor neurons. This process leads re-innervation by the expansion of pre-existing motor units and is aimed at returning to function previously denervated muscle fibers. This dynamic denervation/re-innervation cycle successfully compensates for neuronal loss, with little decline in global strength and only slightly reduced control. However, there is evidence that this compensatory mechanism starts failing with aging. Some denervated fibers are not successfully re-innervated, become apoptotic, and are not replaced by new fibers. It is hypothesized that this phenomenon contributes to a progressive decline in muscle mass and strength with aging.
The reason for a progressive impairment of the re-innervation process with aging is unknown, but some lines of evidence point to changes that occur with aging in the neuromuscular junction (NMJ), which is the synaptic interface between a branch of a motor neuron and muscle cells. Over the last decade, age-associated degeneration of the NMJ has been reported. It has been proposed that such changes may be causally related to the decline in muscle mass and function that occurs in most aging individuals. However, whether changes in the NMJ precede or follow the decline of muscle mass and strength remains unresolved. In this report, we review our current understanding of the events that lead to NMJ dysfunction with aging, including studies on biomarkers, signaling pathways, and animal models. We propose that interventions aimed at preventing the deterioration of the NMJ should be aimed at reversing the mechanisms that lead to NMJ degeneration with aging. It is important to underline that our comprehension of the global mechanism that lead to NJM impairment with aging is still patchy.
COLD SHOCK PROTEINS AND NEURODEGENERATION
Thursday, January 15, 2015
You may be familiar with the research interest in heat shock proteins and their role in cellular health and repair. They are a part of the reaction to heat necessary to allow individuals to survive high temperatures. There is an analogous but different reaction to the other end of the temperature scale, also intended to assure survival under potentially damaging low temperatures. Here is an interesting result in which researchers investigate some of the mechanisms involved in the cellular reaction to cold, arising out of the study of hibernation in mammals:
It has long been known that during hibernation, where a mammal's core temperature cools to well below normal body temperature, synapses (the connections between brain cells) are depleted. This allows the animal to enter a state of 'torpor', similar to a very deep sleep but where no brain activity occurs, allowing the animal to survive without nutrition for weeks or months. As the animal comes out of hibernation and warms up, connections between brain cells are reformed and the number of synapses once again rises, restoring normal brain activity. In humans, a reduction in body temperature (hypothermia) is known to protect the brain. For example, people have survived hours after a cardiac arrest with no brain damage after falling into icy water. Artificially cooling the brains of babies that have suffered a loss of oxygen at birth is also used to protect against brain damage.
Cooling and hibernation lead to the production of a number of different proteins in the brain known as 'cold-shock' proteins. One of these, RBM3, has been associated with preventing brain cell death, but it has been unclear how it affects synapse degeneration and regeneration. Knowing how these proteins activate synapse regeneration might help scientists find a way of preventing synapse loss, without the need for actual cooling.
Researchers reduced the body temperature of healthy mice to 16-18ºC - similar to the temperature of a hibernating small mammal - for 45 minutes. They found that the synapses in the brains of these mice, which do not naturally hibernate, also dismantled on cooling and regenerated on re-warming. The team then repeated the cooling in mice bred to reproduce features of neurodegenerative diseases (Alzheimer's and prion disease) and found that the capacity for synapse regeneration disappeared as the disease progressed, accompanied by a disappearance of RBM3 levels. When the scientists artificially boosted levels of the RBM3 protein they found that this alone was sufficient to protect the Alzheimer and prion mice, preventing synapse and brain cell depletion, reducing memory loss and extending lifespan.
LIFESPAN AND HEALTHSPAN IN NEMATODE LONGEVITY MUTANTS
Thursday, January 15, 2015
All things being equal if you extend life by slowing aging, meaning a slowing of the pace of damage accumulation, then you end up with a longer period of disease and frailty in later life simply because life is longer overall. More time is spent at a given level of damage. All things are not equal, however, and the mechanisms and interaction between damage and biological systems are quite complicated: it isn't a straightforward linear path from youthful function to aged dysfunction. So the end result of slowing aging by altering the operation of metabolism could be either less frailty or more frailty, and the outcome could vary widely by both species and method of slowing aging.
Overall it is better to aim for rejuvenation through repair of damage rather than altering metabolism to slow down aging by reducing the pace of damage accumulation. In the case of damage repair there is no ambiguity about outcomes: there will be a restored set of biological systems with less dsyfunction as a result, and the more comprehensive the repair treatments, the better the outcome for the treated individual.
Despite the fact that there are now many, many ways of lengthening life in lower animals such as the nematode species Caenorhabditis elegans, I don't recall much in the way of examination of time spent in frailty, as is carried out in this study:
Aging research has been very successful at identifying signaling pathways and evolutionarily conserved genes that extend lifespan with the assumption that an increase in lifespan will also increase healthspan. However, it is largely unknown whether we are extending the healthy time of life or simply prolonging a period of frailty with increased incidence of age-associated diseases. Here we use Caenorhabditis elegans, one of the premiere systems for lifespan studies, to determine whether lifespan and healthspan are intrinsically correlated.
We conducted multiple cellular and organismal assays on wild type as well as four long-lived mutants until animals reached 80% maximum lifespan (insulin/insulin-like growth factor-1, dietary restriction, protein translation, mitochondrial signaling) in a longitudinal manner to determine the health of the animals as they age. We find that some long-lived mutants performed better than wild type when measured chronologically (number of days). However, all long-lived mutants increased the proportion of time spent in a frail state.
Together, these data suggest that lifespan can no longer be the sole parameter of interest and reveal the importance of evaluating multiple healthspan parameters for future studies on antiaging interventions. We show lifespan and healthspan can be separated and all of the long-lived mutants extend the period of frailty as a consequence. If applied to humans, this would likely lead to unsustainable healthcare costs and demonstrates the importance of examining healthspan as opposed to lifespan for future research.
INVESTIGATING IRON IN AGING
Friday, January 16, 2015
This work on iron and aging in nematodes is interesting but still quite speculative at this stage: wait for studies along these lines to take place using mice before paying too much more attention to it.
It's been known for decades that some metals, including iron, accumulate in human tissues during aging and that toxic levels of iron have been linked to neurologic diseases, such as Parkinson's. Common belief has held that iron accumulation happens as a result of the aging process. But research in the nematode C. elegans shows that iron accumulation itself may also be a significant contributor to the aging process, causing dysfunction and malfolding of proteins already implicated in the aging process.
Researchers began manipulating the nematode's diet. "We fed iron to four day-old worms, and within a couple of days they looked like 15 day-old worms. Excess iron accelerated the aging process." Excess iron is known to generate oxidative stress and researchers expected to see changes in the worm based on that toxicity. "Instead, what we saw looked much more like normal aging. The iron was causing dysfunction and aggregation in proteins that have already been associated with the aging process. Now we're wondering if excess iron also drives aging."
Researchers also treated normal nematodes with the FDA-approved metal chelator CaEDTA - a drug that's used in humans at risk for lead poisoning. The drug slowed age-related accumulation of iron and extended the healthspan and lifespan of the nematodes. Researchers also gave the drug to worms genetically bred to develop specific protein aggregations implicated in human disease. The chelator was also protective in those animals. "This is a phenomena that has not been extensively studied by aging researchers and it's an area that has potential for positive exploitation, but CaEDTA has a very blunt mechanism of action and is associated with dangerous side effects in humans and the track record for other chelators is not well established."
AN ATTEMPT TO COMPENSATE FOR DEFICIENCIES IN STEM CELLS DERIVED FROM HEART FAILURE PATIENTS
Friday, January 16, 2015
One of the ongoing themes in stem cell research is that cells and environments in old people do not function correctly, this interferes with most potential treatments in numerous ways, and thus scientists are in search of fixes and workarounds. Most potential applications of regenerative therapies involve the treatment of age-related diseases, and so the industry must address these issues in order to succeed. It is good for all of us that this incentive exists, as it spurs progress in an important area of research. The paper referenced below is a modest example of one approach in this field, in which researchers catalog some of the differences between the stem cells of healthy individuals and heart failure patients, noting that these cause issues when trying to expand a cell sample into a large enough number of cells for a transplant treatment:
Chronic heart failure (HF) is one of the most common causes of death worldwide, and the only radical treatment for severe chronic HF remains to be heart transplantation. It is necessary to search for new therapeutic approaches to restore the structure and function of cardiac muscle. In the past two decades cell therapy has been considered as the prospective therapeutic approach to the treatment of cardiovascular diseases including HF. The cells intended for cell therapy must have certain characteristics: they should be relatively easy available, safe, and demonstrate efficiency in stimulation of reparation of cardiac muscle. Different cell types were tested in regeneration protocols and by now multipotent mesenchymal stromal cells from bone marrow (BM-MMSC) remain to be the most attractive, and one of the best characterized substrates for clinical applications: these cells could be rapidly and efficiently expanded in vitro and this type of cells is known to be immunologically privileged.
Many researchers still believe that the ideal substrate for cell therapy are autologous cells. However, it was demonstrated in several animal-based studies that donor-specific factors could attenuate stem cell functions and reduce regenerative potential. Influence of donor's age and gender on the properties of BM-MMSC has been studied actively in recent years in many laboratories, but the studies of impact of chronic cardiovascular disorders, including HF, on multipotent progenitor cells are limited.
In present work we have found that a number of properties were altered in BM-MMSC derived from HF patients compared to healthy donor-derived BM-MMSC. In particular, in HF-derived BM-MMSC a decrease in proliferative activity during in vitro expansion was detected, accompanied by upregulation of signaling pathways that control both tissue regeneration and fibrosis. We have demonstrated that decrease in efficiency of expansion could be markedly improved by culturing of BM-MMSC under moderate hypoxic conditions and substantial decrease in cell seeding density. Further experiments are necessary to learn how to manipulate the culturing conditions in order to predict and, most importantly, control the balance between proliferation rate, replicative senescence, regenerative potential, pro-fibrotic and anti-fibrotic properties of cellular sample intended for experimental or therapeutic protocols.