CPHPC, now called miridesap, is a cautionary tale of what all too often happens to promising approaches in the field of medical development, once they advance to the point of expensive clinical trials and the requirement for partners with deep pockets to fund those trials. Miridesap was one of the earlier methodologies demonstrated to clear out transthyretin amyloid from tissues. This form of amyloid appears to be an important contribution to risk of cardiovascular disease, as well as a factor in osteoarthritis, and the evidence suggests it is the majority cause of death in supercentenarians. Its accumulation in old tissues is a form of damage, one of the root causes of aging. Ways to remove transthyretin amyloid should be pursued aggressively, but so far most of the effort in the research community has focused on the inherited form of transthyretin amyloidosis, using therapies that are not all that helpful for the age-related form of amyloidosis.

The first attempt to develop miridesap with a major pharmaceutical concern failed in the 1990s and early 2000s. The company founded to develop miridesap, Pentraxin Therapeutics, then partnered with Glaxosmithkline, GSK, at which point it took something like nine years to get to the point of running a small trial in 2015. That trial was successful, but thereafter GSK discontinued the work. The problem is less that initiatives sometimes fail, and more that (a) major pharmaceutical entities do not have the right incentives operating in order to carry out development programs rapidly and reliably, and (b) their ownership of intellectual property rights prevents anyone else from trying variants on the same approach, even when very little is being done, or the research is entirely halted. While in principal it is possible to obtain rights to a moribund program, in practice that is far from easy, and too expensive for most of the people who would consider trying it. This might all be seen as a symptom of excessive regulatory costs. Either way, research and development languishes.

Miridesap has a third act, however, one that has been in the works for a few years now. Those involved are attempting to use it as a way to remove amyloid-β in Alzheimer's disease, and are organizing a trial that is now recruiting. It will be interesting to see whether this works well enough to make it competitive. It is certainly less harsh on patients in comparison to the immunotherapies that make up the majority of attempts to treat Alzheimer's disease. Perhaps if this works, then the rights for use against transthyretin amyloid can be wrested from GSK, or GSK might be convinced to proceed again with that line of development.

NIHR-backed trial to test miridesap in Alzheimer's

Mark Pepys, who has been working on amyloidosis for 43 years, discovered way back in the 1980s that SAP, a normal, nonfibrous circulating plasma glycoprotein, is involved in the formation of amyloid deposits. He went on to show it is always present as a minor component of human amyloid deposits of all types, and that it prevents amyloid fibrils from being cleared via opsonization and phagocytosis. Despite attracting the interest of big pharma, attempts to translate those insights to the clinic have been slow to bear fruit.

A collaboration with Roche Holding AG that started in 1993 led to the discovery of miridesap (then known as CPHPC). When tested in the rare disease systemic amyloidosis, miridesap removed SAP from the blood, but could not shift large deposits of amyloid from organs. Amyloidosis patients treated with miridesap remained stable, but the deposits did not disappear. After Roche handed back rights in 2008, Pepys formed a collaboration with Glaxosmithkline to develop miridesap in combination with an anti-SAP antibody for treating amyloidosis. The rationale was to remove SAP from the blood and then use the antibody to target SAP in amyloid, activating the complement system to clear the deposits. That played out in a phase I study published in 2015, but a phase II, 30-patient study of the combination therapy recently was suspended by GSK.

Meanwhile, Pepys has been pursuing development of miridesap as a monotherapy in Alzheimer's disease. His basis for thinking miridesap can remove amyloid from the brain when it was not effective in removing it from other organs, is related to the much lower level of SAP that needs to be sponged up. SAP is generated and catabolized only in the liver and is not expressed in the brain. In a mouse model of Alzheimer's that is genetically engineered to generate human SAP, depleting SAP in the bloodstream removed all detectable SAP from amyloid in the brain.

The study is funded with $6.2 million in grants from NIHR. GSK has no commercial interest, but has assisted with the logistics of setting up the Despiad (Depletion of serum amyloid P component in Alzheimer's disease) trial. Patients in the trial will be required to inject miridesap three times a day over 12 months and to undergo a wide range of tests, including PET scans, lumbar punctures, and cognitive assessments. Pepys hopes the 100-patient, double-blind, placebo-controlled Despiad trial, will show the reduction in SAP levels translates into clinical benefit.

Researchers here describe one very thin slice of the sweeping metabolic changes produced by exercise and calorie restriction. Both interventions act to reduce blood pressure, most likely through numerous distinct mechanisms. One of those mechanisms involves raised levels of β-hydroxybutyrate, an effect that can in principle be mimicked or enhanced via carefully designed therapies. The raised blood pressure that occurs with age is one of the more destructive changes that take place with aging; it is in effect a way to translate accumulating damage and dysfunction at the cellular level into a physical bludgeon that destroys delicate structures throughout the body. Blood pressure is so influential in aging that current pharmacological methods that force a lowered blood pressure result in sizable reductions in disease incidence and mortality even though they fail to address the underlying damage of aging in any way.

Hypertension is a modifiable risk factor for cardiovascular disease and exercise is widely recommended for hypertensive patients as a lifestyle modification because of the well-documented beneficial effect of exercise on lowering blood pressure (BP). Similarly, calorie restriction, although not widely recommended for patients, is also documented to lower hypertension. Interestingly, both exercise and calorie-restriction are associated with increased circulating levels of ketone bodies such as β-hydroxybutyrate (βOHB). βOHB is produced predominantly in the liver, transported to other tissues, and traditionally recognized as a vital alternative metabolic fuel during times of starvation. However, contemporary evidence indicates that apart from serving as energy fuels, ketone bodies such as βOHB block inflammasome-mediated inflammatory diseases and thereby play a prominent role in maintaining physiological homeostasis.

In contrast to exercise and calorie-restriction, consumption of high salt promotes hypertension. Studies on the effects of dietary salt have focused mainly on organs and tissues relevant to BP regulation such as kidney, vasculature, heart, and brain. A recent report suggests that a reduction in salt intake serves as an additional interventional approach for reducing the risk for developing metabolic syndrome, of which, hypertension is one of the hallmark features. Taken together, these studies point to an intriguing possibility that a high salt diet induced a deleterious effect on hypertension and could mechanistically represent the opposite scenario to that of the protective effects of exercise and calorie-restriction on hypertension by altering the levels of metabolites such as ketone bodies.

Here, we examined this possibility, first by an untargeted mass spectrometry-based plasma metabolomics study and discovered altered ketogenesis and over-activation of renal Nlrp3 as a key mechanistic link between high salt and hypertension. These results indicated that a high salt diet has mechanistically opposite effects of exercise and calorie-restriction on BP. Next, we demonstrated that nutritional intervention with 1,3-butanediol, a precursor of the endogenous ketone body, βOHB, reversed the adverse effects of high salt induced renal Nlrp3-mediated inflammation, fibrosis, and hypertension. Based on these observations in the Dahl S rat, which is a salt-sensitive pre-clinical model of hypertension, we propose dietary intervention with 1,3-butanediol as an intriguing strategy for the clinical management of salt-sensitive hypertension.

Link: https://doi.org/10.1016/j.celrep.2018.09.058

This open access paper is an example of a model of future life expectancy that projects existing trends, with a little variation in here and there based on whether or not public health measures related to smoking and diet prove to be more successful or less successful. It predicts an average global increase in life expectancy of 4 to 5 years by 2040. In recent years I would have said that this is probably incorrect. I think we are at the point now in the development of rejuvenation therapies at which I can say that it is definitely incorrect. Any study that fails to consider progress in the treatment of aging as a medical condition is disconnected from reality.

Twenty years from now senolytic drugs will be used by a sizable percentage of the world's population, and will cost cents per dose. They will dramatically reduce the suffering and death resulting from inflammatory age-related diseases by removing some fraction of lingering senescent cells from old tissues. The first such therapies already exist today, are easily available, and some cost a few hundred dollars per dose or less. It isn't hard to see that the use of senolytics will spread like wildfire just as soon as the first clinical trials report their results over the course of 2019. Further consider that this is just one branch of rejuvenation biotechnology. Numerous other branches are under development today, and will certainly be clinically available by the late 2020s. The historical trend in life expectancy will be smashed; life expectancy will jump upward quite dramatically.

This was the first study to forecast a comprehensive set of cause-specific and all-cause mortality and associated indicators using a framework that allows for exploring different scenarios for many risk factors and other independent drivers. In our reference scenario, life expectancy was forecasted to continue increasing globally, and 116 of 195 countries and territories were projected to have significant advances in life expectancy by 2040. Gains were projected to be faster among many low-to-middle SDI countries, indicating that inequalities in life expectancy could narrow by 2040.

As shown by the better health scenarios, greater progress might be possible, yet for some drivers such as high body-mass index (BMI), their toll will rise in the absence of intervention. We forecasted global life expectancy to increase by 4.4 years for men and 4.4 years for women by 2040, but based on better and worse health scenarios, trajectories could range from a gain of 7.8 years to a non-significant loss of 0.4 years for men, and an increase of 7.2 years to essentially no change (0.1 years) for women.

In 2040, Japan, Singapore, Spain, and Switzerland had a forecasted life expectancy exceeding 85 years for both sexes, and 59 countries including China were projected to surpass a life expectancy of 80 years by 2040. At the same time, Central African Republic, Lesotho, Somalia, and Zimbabwe had projected life expectancies below 65 years in 2040, indicating global disparities in survival are likely to persist if current trends hold.

Taken together, our forecasts point to a world where most populations are living longer and many health improvements are likely to occur if current trajectories hold; at the same time, such gains are not without potential important social consequences, particularly if long-term planning and policy design are not fully considered today.

An important finding is that in the reference scenario, we forecasted slower progress in 2040 than that achieved in the past; however, in the better health scenario, global life expectancy improvements exceeded gains that occurred from 1990-2016. This forecasted slowdown in the reference scenario is rooted in a combination of several factors. First, some risks were projected to worsen in the future, most notably high BMI. Second, past progress on other leading risk factors for premature mortality, namely tobacco and ambient particulate matter air pollution, was highly variable and thus such heterogeneity was projected through 2040. Third, several countries that have already achieved higher levels of life expectancy have also had stagnated gains.

Link: https://doi.org/10.1016/S0140-6736(18)31694-5

This open access paper reviews the interactions between cellular senescence, autophagy, and immunosenescence, with chronic infection as a mediating mechanism. Given the present state of knowledge and biotechnology, it is challenging enough to look at any two aspects of the aging body and consider how they might interact in isolation, but this can only ever be a thin slice of the bigger picture. All systems and states in our biochemistry interact with one another in some way, directly or indirectly, and examining ever larger sets of relationships between greater numbers of systems and states is the path to greater understanding of aging as a phenomenon. It is also somewhat beyond present capabilities, a complex, challenging endeavor for the scientists of future decades, which is why bypassing the need for this sort of understanding is highly desirable when working towards therapies to treat aging. We cannot afford to wait for a near complete knowledge of the progression of aging.

The state of cellular senescence, in which replication is shut down, can be a reaction to damage. It is one of the ways in which cancer risk is sufficiently minimized to allow higher forms of multicellular life to exist. Senescent cells are unfortunately harmful to surrounding tissues, and their accumulation with age is one of the root causes of degenerative aging. Autophagy is a collection of cellular damage control processes, responsible for recycling broken and unwanted proteins or structures in the cell. Loss of autophagy to the point of excessive accumulation of molecular damage is one way for cells to become senescent, and unfortunately autophagy declines with age. Immunosenescence is the aged state of the immune system, characterized by chronic inflammation and incapacity. In later life, the immune system becomes far less effective in removing damaged cells, such as senescent cells, as well as less effective when it comes to a defense against invading pathogens.

Even when simply considering just these three line items, the potential interactions are complex and challenging to rigorously prove. The authors of this paper advance the common view that chronic infection impairs autophagy, and thus in turn generates increased numbers of senescent cells, which accelerates the progression of immunosenescence.

Chronic Infections: A Possible Scenario for Autophagy and Senescence Cross-Talk

Cellular senescence is induced as a consequence of cellular damage accumulation, with the extent of activation directly depending on a fine-tuned balance between cellular conditions generating damage and those involved in counteracting them. The autophagic pathway plays a key role in preventing cell damage accumulation, however, the aging process leads to a decrease in autophagy capacity, and therefore also its effectiveness. In this context, senescence activation shows a more preponderant protective role.

The immune system does not escape from aging effects and displays senescence characteristics in aged individuals. Immunosenescence refers to the state of dysregulated immune function that contributes to the increased susceptibility to infections, autoimmune diseases, or cancer. Aged individuals are predisposed to more severe symptoms from certain infections and they do not mount an effective immune response upon vaccination. In general, aged populations fail to generate an appropriate innate and adaptive immune response against microorganisms, thus it becomes clear that senescence is involved in this failure.

Besides the normal occurrence of immunosenescence, several pathogen microorganisms accelerate the activation of senescence and predisposal to premature immunosenescence. For instance, hosts infected with bacteria such as P. aeuruginosa, M. tuberculosis, or H. pylori, some viruses, including HCMV, or the parasite T. cruzi, show characteristics of immunosenescence. A common issue of all of these pathogens is that they are able to generate chronic infections. In each of these, regardless of the fact that the host is faced with the same antigen several times during its lifetime, the immune response is inefficient. Furthermore, data shows that this condition generates an immune exhaustion and immunosenescence seems to be the major causative factor offering the pathogens an extra advantage since their elimination by the host tends to be even less effective.

Interestingly, a common characteristic of chronic infections is the autophagy blockage that usually occurs during autophagosome maturation, representing a factor that could contribute to or accelerate immunosenescence activation since it predisposes cells to damage accumulation. Deeper exploration to elucidate whether the activation of senescence in chronic infection is a consequence of autophagy impairment produced by pathogens to avoid degradation or, alternatively, whether it is a mechanism employed by the host to diminish infection spreading when the degradation of the pathogens has been halted. This exploration is needed to further understand the infection-autophagy-senescence relationship. With the available data, we hypothesize that chronic infections induce senescence with similar characteristics of aging, i.e., increase of inflammatory state and autophagy inhibition.

There is plenty of evidence for exercise of all sorts to improve cognitive function in later life. That outcome might be mediated via increased blood supply to the brain, which is a particularly energy-hungry organ. Or it might be mediated via improved mitochondrial function, for much the same underlying reasons relating to energy demands. Or via any one of a number of other related mechanisms that one can link to exercise. Strength training is thought helpful in yet another way, via building or retaining muscle mass that then in turn alters metabolism in favorable ways (that usually lead back to blood flow and mitochondrial function in some way).

There is some overlap between researchers interested in strength training and those interested in ischemic conditioning, a form of intermittent restriction of blood flow that appears synergistic with exercise. One can view this all from the perspective of triggering stress responses. Exercise triggers stress responses, and so does transient ischemia. The former is far more explored, and the latter is harder to undertake safely. One might also view this area of research as the preliminary exploration that leads to drug candidates somewhere down the line, ways to artificially trigger beneficial stress responses, but I think that the past few decades of work on calorie restriction have demonstrated that to be slow, expensive, and challenging.

The integrity of the musculature and the muscle strength is of great importance throughout the entire life span. Age-related decreases in muscle mass and strength are also associated with morphological losses in the brain and decreased cognitive functions. There is growing evidence with respect to positive effects of physical activity preventing and treating morphological and functional losses in muscles and the brain. In recent years, evidence has emerged emphasizing the existence of a bidirectional relationship between physical performance and brain health. The bidirectional relationship suggests that physical training may be a valuable intervention strategy to decelerate not only physical but also cognitive decline in old age. However, the exercise type (e.g., resistance training, endurance training) and exercise variables (e.g., load, duration, frequency), which would be optimal to efficiently enhance cognitive performance are largely unknown.

A promising and cost-effective physical intervention strategy which preserves and enhances both, physical performance (especially with regard to the musculature) and cognitive functions, is resistance training (also known as strength training). A relative new method in the field of resistance training is blood flow restriction training (BFR). While resistance training with BFR is widely studied in the context of muscular performance, this training strategy also induces an activation of signaling pathways associated with neuroplasticity and cognitive functions. Based on this, it seems reasonable to hypothesize that resistance training with BFR is a promising new strategy to boost the effectiveness of resistance training interventions regarding cognitive performance.

Link: https://doi.org/10.3390/jcm7100337

Members of the research community have in recent years exhibited a growing interest in the analysis of gut microbes in the context of metabolism and the pace of aging. Some inroads are being made into better understanding helpful versus unhelpful microbial populations and behaviors, and how exactly their activities might influence health over the long term. It is unclear as to how large this influence is. Perhaps it is in the same ballpark as exercise, but perhaps not. The usual problems arise when comparing results between species, in that short-lived species have greater plasticity of life span, their length of life more readily extended or shortened in response to changing circumstances. It should be no great surprise to find that the practice of calorie restriction, well known to slow aging in near all species tested to date, induces changes in gut microbial populations that conform to alterations that are seen as being helpful for health in other contexts.

The gut microbiota (GM) largely derives nutrients from dietary intake. In this respect, a large number of studies have been reported on the variations of the GM composition occurring according to different diets. The majority of these studies have focused on the comparison of low vs. high energy density (i.e., high fat or high sugar) diets in animals fed ad libitum (AL), showing an increase in the Firmicutes/Bacteroidetes ratio and the proliferation of pro-inflammatory Proteobacteria in the latter condition.These changes occur rapidly and can be partially restored by reverting to the control diet. Animal experimental data also agree with observational studies in humans, where similar taxonomic features were found to be changed between obese and lean individuals.

In addition, the GM composition varies rapidly and significantly in response to macronutrient changes, even when equal numbers of calories are provided. This clearly suggests that the relative abundance of the specific GM members strongly depends on the quality of nutrients they have access to. Hence, given the strong relationship among diet, GM and health, there is a growing interest in developing novel dietary strategies to modulate the composition and, possibly, the metabolic functions of the GM.

Among dietary interventions, caloric restriction (CR) is well known for the health-promoting impact on lipid metabolism and longevity. CR is generally applied without changing the macronutrient composition and solely reducing the caloric intake compared to the AL condition. As a consequence, in experimental models, caged individuals fed a CR diet consume completely their food and then fast for several hours before the next feed administration. We have recently reported that CR induces a rapid change (as early as after 3 weeks of CR) of the GM composition in young rats, that parallels a reduction of triglycerides and cholesterol levels in the blood, and that these changes are maintained up to mid age. In particular, a CR diet enabled the expansion of Lactobacillus rapidly and persistently up to adulthood. CR-induced variation of the GM composition might then play a role in helping extend lifespan and delay the onset of age-related disorders by preserving gut homeostasis. However, the precise biochemical changes the GM undergoes during CR are still undetermined, in the short and in the long term.

Here, we investigated the short- and long-term effects of CR on the rat GM using a metaproteogenomic approach. We show that a switch from ad libitum (AL) low fat diet to CR in young rats is able to induce rapid and deep changes in their GM metaproteomic profile, related to a reduction of the Firmicutes/Bacteroidetes ratio and an expansion of lactobacilli. Specifically, we observed a significant change in the expression of the microbial enzymes responsible for short-chain fatty acid biosynthesis, with CR boosting propionogenesis and limiting butyrogenesis and acetogenesis.

Link: https://doi.org/10.1038/s41598-018-33100-y

There is a point in the life of a young biotech company at which one traditionally appoints an established figure from industry as the CEO. Running a company that is in the public eye due to clinical trials and heading in the direction of an IPO requires a whole different set of skills than were needed for early growth and technical success in development programs. It also tends to be a sign of the changing balance of influence between founders, investors, and industry partners as development programs progress. This happened earlier in the year for Navitor Pharmaceuticals, one of a number of companies working on mTOR inhibitor therapies capable of modestly slowing the aging process.

Talking up one's position is a part of the duties of an industry CEO: a good CEO is an advocate for the company, for the technology, for the industry. That is expected. I point out this commentary from the new Navitor CEO not for the expected content, but rather as an example of our present slow movement though an important tipping point in the great, many-threaded cultural conversation about aging and the prospects for treating aging as a medical condition. The message of the life science community, that aging can be slowed and reversed, is being taken up by industry and media. It is spreading broadly, and more rapidly than in past years.

In short, the goal of bringing aging under medical control is increasingly being taken seriously, finally, after more than twenty years of earnest advocacy and hard-fought, incremental progress in obtaining research funding. Now, the battle must turn to one of steering funding towards the better rather than the worse options for development. When people agree that the goal must be reached, it becomes very important to settle on the best possible strategy.

On that note, I don't think that therapies that function via inhibition of mTOR, based as they are on modulation of dysfunctional metabolism without doing much to address the causes of that dysfunction, have anywhere near as large an upside, considered in terms of additional healthy years of life, as is the case for the SENS approaches to aging. SENS rejuvenation therapies are intended to repair the underlying damage that causes aging, while mTOR inhibition and similar approaches largely adjust harmful reactions to that damage. They are beneficial to some degree, particularly now that it is possible to separate the desirable and undesirable components of the early mTOR inhibitors such as rapamycin. Still, while modest gains are better than nothing, we should be aiming for large gains.

Targeting Aging Comes Of Age

We finally are beginning to understand the biological basis of aging and age-related diseases, making the discovery of new therapies actionable for the first time. Aging and its underlying biological mechanisms are becoming recognized as a catalyst, if not the central catalyst, for a wide range of poorly treated prevalent diseases. This is a promising new area in science providing actionable insights with potential for tremendous impact on human healthspan.

I have been following the field of the biology of aging since the beginning of my career in science, more than thirty years, while working in targeted ways to find and advance new therapies in the areas of metabolic and cardiovascular disease. Recently, I became the CEO of a biotechnology company, Navitor Pharmaceuticals, that is squarely in this space and focused on leveraging new discoveries to target the activity of mTOR (mechanistic target of rapamycin). In many ways, the progress in the field has reached a tipping point and has prompted me to reflect on the advancements.

Chronic conditions of aging are the major cost drivers for healthcare. There are some shocking statistics to be found regarding the cost of chronic conditions affecting our healthcare system. The multiple chronic conditions chartbook published in 2010 by the Agency for Healthcare Research and Quality is a short and fascinating read. Almost half of all people aged 45-64, and 80% of those 65 and over, have multiple chronic conditions. 71 cents of every US healthcare dollar go to treating people with multiple chronic conditions. Just take a moment to think about that. First off, this is a huge portion of our healthcare budget. It's not cancer. It's not rare diseases. It's not cosmetic or elective procedures. It's chronic illnesses, primarily associated with aging.

Id you have one disorder that is commonly associated with aging, chances are you have another or will develop another one. Basically, it's tough to get old. We all know that. But, now science is leading us to harness some fundamental mechanisms of aging. Two core aging mechanisms appear to have emerged as being accessible to new pharmacological intervention - the mechanistic target of rapamycin, or mTOR, and cellular senescence (which is wrapped up in mTOR as well). Drug development approaches using cellular senescence are emerging, and they are fascinating and worthy of attention. It's an exciting time in the aging space, and hopefully one that yields important new medications capable of reducing the personal, societal, and financial burdens of chronic diseases.

Mitochondria are the power plants of the cell, responsible for generating adenosine triphosphate (ATP), a chemical energy store molecule used to power cellular operations. The inner workings of each mitochondrion are energetic and complicated, consisting of a number of interacting protein complexes that collectively perform the work needed to manufacture ATP molecules. Mitochondrial function occupies a central position in the interaction between metabolism and aging for a number of reasons. Firstly, they generate reactive oxygen species (ROS) as a side effect of ATP production, and the flux of ROS is both damaging and a signal to the cell to step up its efforts to repair damage. A little more ROS than usual can be beneficial. Too much ROS is harmful. Secondly, some of the critical proteins in mitochondrial complexes are produced from DNA inside the mitochondria rather than in the cell nucleus, and that DNA is vulnerable to damage. Some forms of mitochondrial DNA damage can produce damaged mitochondria that cause great harm to the cell and surrounding tissue. Thirdly, cells need ATP, and reductions in ATP production have detrimental consequences over time.

There are many ways in which mitochondrial function can be altered through the removal or reduced production of a specific subunit of one of the mitochondrial protein complexes. Some such changes are disastrous, some are beneficial. Why that is the case is a complicated topic. It has a great deal to do with the balance between production of ROS and production of ATP, the needs of cells, and the reactions of cells, particularly the activation of repair and maintenance mechanisms. That balance is different in each case, and it is a slow and expensive process to run through the protein biochemistry needed to gain insight into what exactly is going on under the hood. The paper here is an example of the sort of work that takes place in this part of the field.

Mitochondria play an essential role in many important physiological processes, including aging. Mitochondrial function has been thought to gradually decline with age, while oxidative damage and mitochondrial DNA mutations accumulate. Although complete disruption of mitochondrial function is detrimental or even lethal for many eukaryotes, including humans, accumulating evidence has revealed that partial inhibition of mitochondrial function tends to increase lifespan. In C. elegans, mutations in various mitochondrial electron transport chain (ETC) genes can greatly extend lifespan; these include mutations in isp-1 and clk-1. In addition, RNAi knockdown of various mitochondrial ETC genes prolongs lifespan in yeast, worms, and fruit flies.

The effects of mitochondrial ETC genes on modulating lifespan appear to be complex. Inhibition of some ETC genes increases lifespan, whereas inhibition of others decreases or does not alter lifespan in C. elegans and Drosophila. For example, mutations in mev-1, which encodes a subunit of complex II, causes a short lifespan in worms. In addition, the underlying causes for lifespan regulation by ETC genes remain incompletely understood. For example, the roles of reactive oxygen species (ROS) production and mitochondrial function in aging and lifespan of ETC mutants can be opposite ways. One model interpreting these opposite effects is that moderate mitochondrial impairments increase lifespan until a threshold is reached, beyond which animals display wide-spread damage, shortened lifespan, or even death. Nevertheless, how mitochondrial genes modulate lifespan and whether they function in modulating lifespan in other species remain incompletely elucidated.

ATP synthase, also known as complex V of the mitochondrial respiratory chain, is the primary cellular energy-generating machinery. In mammals, ATP synthase deficiency is one of the rarer mitochondrial oxidative phosphorylation deficiencies. ATP synthase is also intimately linked to aging. In worms, genetic inhibition of the atp-2 gene, which encodes a subunit in complex V, leads to developmental delay and increased lifespan. Additionally, a genome-wide RNAi screen revealed that RNAi knockdown of subunits atp-3, atp-5, or asb-2 prolongs worm lifespan. However, the underlying mechanism for lifespan extension due to inhibition of these subunits in the ATP synthase remains unclear. As ATP synthase is highly conserved throughout evolution, understanding the role of the ATP synthase in lifespan regulation can lead to untangling of the complexity of mitochondrial ETC genes in modulating lifespan.

Link: https://doi.org/10.1038/s41598-018-32025-w

The practice of calorie restriction reliably slows aging and extends life span in most species tested to date. The degree to which this happens is much reduced in longer-lived species, but a detailed understanding of why this is the case is yet to be assembled. It makes sense from an evolutionary perspective: extended health and life in response to famine helps to raise the odds of successful reproduction. Famines tend to be seasonal, and a season is a large fraction of a mouse life span, but only a tiny faction of a human life span. Thus only short-lived species evolve a sizable gain in life span in response to reduced calorie intake, even though the short-term benefits to health appear quite similar in both short-lived and long-lived mammals.

From a biochemical perspective, cellular metabolism is so complex, and calorie restriction changes so much of it, that it remains a major undertaking to try to put everything in order to understand how exactly calorie restriction works. It is clearly an adaptive response, a shift of the whole of metabolism from one state into another, a change of great complexity. Deciphering all of the details is a fascinating scientific endeavor, but one that will come to be of increasingly little relevance to the future of human longevity. Calorie restriction mimetic therapies that modestly slow aging are hard to construct, while rejuvenation therapies based on repair of the damage that causes aging will deliver far greater benefits with far lower expense.

In 1989, the anti-aging and prolongevity actions of calorie restriction (CR) were explained from the evolutionary viewpoint of organisms having evolved adaptive response systems to maximize survival during periods of food shortage. On the basis of this evolutionary viewpoint, we divided the beneficial actions of CR into two systems; "systems activated under sufficient energy resource conditions" and "systems activated under insufficient energy resource conditions". The former is activated under natural environmental conditions that grant animals free use of energy by providing a plentiful food supply. In other words, when there is grace for free use of energy, animals grow well, reproduce more, and store excess energy as triglyceride in white adipose tissue for later use, but not to such an extent that they become obese. The latter is activated under natural environmental conditions that do not permit free use of energy because of food shortages.

In other words, when there is no grace for free use of energy, animals suppress growth and reproduction and shift energy use from growth and reproduction to maintenance of biological function, but not to such an extent that they become severely starved. Adaptation to natural environmental changes is a top priority for survival in animals. On the basis of the adaptive response hypothesis, we propose a suite of mechanisms for the beneficial actions of CR. Since experimental CR conditions can mimic insufficient energy conditions, we hypothesized that CR suppresses "systems activated under sufficient energy conditions" and activates "systems activated under insufficient energy conditions", and additively induces anti-aging and prolongevity actions. The first set of systems involves GH/IGF1, FOXO, mTOR, adiponectin and BMAL1 signaling, and CR appears to suppress these anabolic reactions. The second set of systems involves SREBP-1c/mitochondria redox, SIRT and NPY signaling, and it is likely that CR activates these reactions to make optimal use of insufficient energy resources.

Studies using monkeys suggest that the beneficial actions of CR may occur in humans as well as other mammals. Ongoing CR research focuses on two themes, i.e. elucidation of the molecular mechanisms of CR, and development of CR mimetic medicines. We consider development of novel CR mimetic medicines to be difficult without an understanding of the molecular mechanisms of CR. To develop CR mimetic medicines that are applicable to humans, further studies are therefore required on the molecular mechanisms of CR, particularly in non-human primates. In this report, we propose that the molecular mechanisms of beneficial actions of CR should be classified and discussed according to whether they operate under rich or insufficient energy resource conditions. Future studies of the molecular mechanisms of the beneficial actions of CR should also consider the extent to which the signals/factors involved contribute to the anti-oxidative, anti-inflammatory, anti-tumor and other CR actions in each tissue or organ, and thereby lead to anti-aging and prolongevity.

Link: https://doi.org/10.18632/aging.101557

Our community year end fundraiser for 2018 will soon be underway to support scientific programs for the development of rejuvenation therapies carried out at the non-profit SENS Research Foundation. As was the case last year, once again Fight Aging! and a few fellow travelers will assemble a challenge fund to encourage new SENS Patrons to set up subscriptions to make monthly or yearly recurring donations to the SENS Research Foundation. The first year of any such new donations will be matched dollar for dollar from the challenge fund.

We think that recurring donations are important: the more that our community supports the SENS programs by providing a regular supply of funding, the easier it becomes for the SENS Research Foundation staff to plan ahead and commit to long-term projects. In past years this initiative has been a success: our matching fund was met last year, and the new monthly donors largely stick around for the long term to continue to support SENS rejuvenation research. This year regular donor Josh Triplett is going above and beyond to put up $36,000 to encourage new SENS Patrons to make the leap. Christophe and Dominique Cornuejols are contributing $12,000, and I myself will put in $6,000. We are looking for other challenge fund donors to join us in this initiative. Do you want to make a sizable difference to the future of human health and longevity? This is how it is done.

The SENS Research Foundation uses our donations to fund a range of scientific work on the foundations of rejuvenation therapies, focused on those areas that are furthest behind or that most need unblocking in order to achieve meaningful progress. These are all programs that achieve rejuvenation through repair: validating the list of cell and tissue damage that lies at the roots of aging, and then reversing these forms of damage, one by one. It is in large part thanks to the advocacy, networking, and funding provided by the SENS Research Foundation, and by the Methuselah Foundation before it, that rejuvenation research is as far ahead as it is. When the SENS programs started, popular culture and the scientific community were opposed to any initiative aiming to produce rejuvenation via targeting the molecular damage that causes aging, despite decades of evidence to strongly support this strategy.

In recent years the naysayers have been proven clearly and categorically wrong. Clearance of senescent cells through the use of senolytic therapies has been shown to produce rejuvenation in mice. The first such treatments are in human trials, in development by multiple biotech companies, and being used by a growing number of self-experimenters worldwide. That today there is a new and rapidly growing senolytics industry, poised to deploy rejuvenation therapies that can remove some of the burden of senescent cells in older individuals, is due in large part to the network of advocacy, science, and funding centered on the SENS Research Foundation and Methuselah Foundation. Clearance of senescence cells was in the SENS proposals, front and center, from the very start. Back then, at the turn of the century, the goal of rejuvenation was widely ridiculed. Nonetheless, with persistence, persuasion, and the support of our community of everyday philanthropists, here we are today, embarking upon the construction of an industry that aims to reverse aging.

Senolytics are just the start. They are only a part of the story, and only a narrow slice of the complete human rejuvenation that remains only a possibility, rather than a certainty. Scores of other equally important and beneficial projects under the SENS umbrella of repair therapies are still comparatively neglected, or blocked by the lack of tools, or blocked by the lack of funding, or lacking strong champions in the research community. We can help to change this. We did a great deal to make that change come about for senescent cell clearance, and we can do the same for mitochondrial DNA repair, for breaking the cross-links that stiffen tissues, for clearing amyloids and other harmful metabolic wastes, and more. We shine the light that shows the way, and, given time and resources, we are successful.

Give some thought to joining us. A future in which being old does not mean being sick and diminished is a future worth bringing into existence. We can all help in some way to make this vision a reality.

I think it is entirely appropriate to greet the advent of senolytics with enthusiasm. These treatments are the first legitimate rejuvenation therapies to successfully target one of the root causes of aging, the accumulation of lingering senescent cells in old tissues. The first human trial data is approaching publication, but even before it arrives, the evidence to date strongly suggests that meaningful levels of rejuvenation can be achieved in old people at a very low cost. The first senolytic drugs (such as dasatinib and navitoclax) and plant extracts (such as fisetin and piperlongumine) cost very little, and remove only some senescent cells, no more than half in some tissues, and far fewer than that in others. Nonetheless, in mouse studies they reliably reduce chronic inflammation, reverse the progression of numerous conditions ranging from arthritis to Alzheimer's disease, and extend healthy life span even when applied a limited number of times in very late life.

As we get older, more and more of our the cells in our bodies become dysfunctional and enter into a state known as senescence. These senescent cells no longer divide or support the tissues and organs of which they are part; instead, they secrete a range of harmful inflammatory chemical signals, which are known as the senescence-associated secretory phenotype (SASP). Dr. Judith Campisi from the Buck Institute for Research on Aging, along with her research team, identified that senescent cells secreted the various harmful chemicals that characterize the SASP in 2008, which was when interest in senescent cells really began.

The SASP is a real problem: it increases inflammation, harms tissue repair and function, causes the immune system to malfunction, and raises the risk of developing age-related diseases such as cancer. Even worse, the SASP also encourages nearby healthy cells to become senescent, so even a very small number of senescent cells can cause big problems. Normally, senescent cells destroy themselves by a self-destruct process known as apoptosis or are cleared away by the immune system. Unfortunately, as we age, the immune system becomes weaker, and the senescent cells start to build up in the body. The accumulation of senescent cells is considered to be one of the reasons why we age and develop age-related diseases.

With these experiments, the biotechnology industry had initial proof that targeting one of the aging processes directly could improve health by delaying aging in mice; this began the search to develop therapies that target and destroy these harmful cells. This was the birth of a new class of drugs and therapies that would become known as senolytics. So far, there have been a number of drugs and naturally occurring compounds with senolytic potential and multiple mouse experiments demonstrating that the clearance of these cells can delay the onset of diseases such as cancer, heart disease, osteoporosis, arthritis, and Alzheimer's.

Interest in senolytics has seen a meteoric rise in the last couple of years, with investment money pouring in as confidence in the approach has reached new heights. There are also a number of companies developing therapies to destroy senescent cells, and it is likely that more will join them in the coming years. Leading the charge is Unity Biotechnology, which was founded in 2011 and has raised over $385 million in funding since then. Other companies are hot on its heels developing ways to seek and destroy these harmful cells. Oisin Biotechnologies, based in Seattle, is one such company. Founded in 2016, it has raised around $4 million to date and is developing a unique lipid nanoparticle-based system to deliver senolytic and cancer therapies. Cleara Biotech, based in the Netherlands, and Spain-based Senolytic Therapeutics are also busy developing senolytic therapies.

Link: https://www.leafscience.org/senolytics-target-aging/

Naturally grown tissues are intricately structured, and the physical properties of tissue derive from the patterning of cells and their behavior in generating a supporting extracellular matrix. This natural complexity ensures that there is still a great deal of work to be accomplished when it comes to the 3-D bioprinting of functional tissue structures; not all tissues can be produced using the current state of the art systems, or at least not in a useful state. The work here is an example of the sort of incremental advance needed to produce tissues that are closer in form and function to those growing naturally inside bodies.

The 3-D-printing method, which took two years to research, involves taking stem cells from the patient's own body fat and printing them on a layer of hydrogel to form a tendon or ligament which would later grow in vitro in a culture before being implanted. But it's an extremely complicated process because that kind of connective tissue is made up of different cells in complex patterns. For example, cells that make up the tendon or ligament must then gradually shift to bone cells so the tissue can attach to the bone. "This technique is used in a very controlled manner to create a pattern and organizations of cells that you couldn't create with previous technologies. It allows us to very specifically put cells where we want them."

To do that, the team used a 3-D printer typically used to print antibodies for cancer screening applications. The researchers developed a special printhead for the printer that can lay down human cells in the controlled manner they require. To prove the concept, the team printed out genetically-modified cells that glow a fluorescent color so they can visualize the final product. The technology is initially designed for creating ligaments, tendons and spinal discs, but in the future it could be adapted to any type of tissue engineering application, such as the 3-D printing of whole organs, an idea researchers have been studying for years.

Link: https://unews.utah.edu/the-fine-print/

Salivary glands are one of many small organs that we give little thought to until they fail, and then it becomes difficult to think of anything else. Just like every other tissue in the aging body, that failure becomes more likely with each passing year, with the accumulation of molecular damage and its consequences. One of the potential approaches to this general category of gradual organ failure is the generation of new organs or new functional tissue for transplantation, building tissues in bioreactors from the starting point of cells. This can in principle fix damage that is internal to an organ by replacing that organ entirely, or augment function of a failing organ with the use of tissue patches. The aged environment and its harmful influence on organ function through signaling will remain a challenge, however, until more general rejuvenation therapies are widely deployed.

Japanese researchers have been working on the tissue engineering of functional salivary glands for some years now, and the paper noted below reports on their latest success. Like most groups in the field, they are focused on discovering the necessary signals and environment that can direct cells to build a specific tissue in the same way that occurs during embryonic development. This is quite different on a tissue by tissue basis, but nonetheless progress is being made. The researchers here can build organoids, small sections of functional salivary gland tissue that are limited in size because they lack a capillary network. An important demonstration of functionality is to implant organoids into an animal and show that they integrate and perform the tasks expected of the naturally grown organ. That rarely implies complete success, as the assessed function usually isn't exactly the same, but nonetheless, it may indicate that the research program has progressed far enough to start thinking about use in human medicine.

Researchers create a functional salivary gland organoid

Salivary glands develop from an early structure called the oral ectoderm, but the actual process is not fully understood. It is known that organ development takes place through a complex process of chemical signaling and changes in gene expression, so the scientists began to unravel what the important changes were. They identified two transcription factors - Sox9 and Foxc1 - as being key to the differentiation of stem cells into salivary gland tissue, and also identified a pair of signaling chemicals - FGF7 and FGF10 - which induced cells expressing those transcription factors to differentiate into salivary gland tissue.

To create an organoid, researchers used a cocktail of chemicals that allowed the formation of the oral ectoderm. They used this cocktail to induce embryonic stem cells to form the ectoderm, and then used viral vectors to get the cells to express both Sox9 and Foxc1. Adding the two chemicals to the mix induced the cells to form tissue that genetic analysis revealed was very similar to actual developing salivary glands in the embryo.

The final step was to see if the organoid would actually function in a real animal. They implanted the organoids into actual mice without saliva glands and tested them by feeding them citric acid. When the organoids were transplanted along with mesenchymal tissue -another embryonic tissue that is important as it forms the connecting tissue that allows the glands to attach to other tissues - the implanted tissues were found to be properly connected to the nerve tissue, and in response to the stimulation secreted a substance that was remarkably similar to real saliva.

Generation of orthotopically functional salivary gland from embryonic stem cells

Organoids generated from pluripotent stem cells are used in the development of organ replacement regenerative therapy by recapitulating the process of organogenesis. These processes are strictly regulated by morphogen signalling and transcriptional networks. However, the precise transcription factors involved in the organogenesis of exocrine glands, including salivary glands, remain unknown. Here, we identify a specific combination of two transcription factors (Sox9 and Foxc1) responsible for the differentiation of mouse embryonic stem cell-derived oral ectoderm into the salivary gland rudiment in an organoid culture system.

Following orthotopic transplantation into mice whose salivary glands had been removed, the induced salivary gland rudiment not only showed a similar morphology and gene expression profile to those of the embryonic salivary gland rudiment of normal mice but also exhibited characteristics of mature salivary glands, including saliva secretion. This study suggests that exocrine glands can be induced from pluripotent stem cells for organ replacement regenerative therapy.

That females live longer than males in numerous species is a topic of some interest to evolutionary theorists and other researchers in the life sciences. There are any number of possible explanations, but that this phenomenon exists in many different species tends to favor evolutionary arguments. Something fundamental to gender as it exists in most higher species is closely tied to aging, and the result is near always females that age more slowly than males. In the research noted here, scientists report on an experiment in fly populations that suggests this longevity difference will arise quite naturally from the differing mating strategies of male and female genders, each under selection pressure to maximize their success in reproduction.

Differences in aging and the length of life between males and females are common in the animal realm. Males often have shorter lifespans than females. Researchers used fruit flies, Drosophila melanogaster, to investigate whether sexual selection lies behind sex differences in aging. They wanted to determine whether the two sexes are affected differently when they are in poorer physical condition, in other words, when they have poorer access to nutrients and energy. In particular, they were interested in the ability of the flies to reproduce, and how this ability changes when the flies age, in a process known as "reproductive aging".

Researchers had manipulated the genetic material of some of the flies, such that they had many small harmful mutations in their genes. These mutations had a negative influence throughout life, meaning that an individual with such mutations converted food to useful energy slightly less efficiently. Thus, even though all of the flies had access to the same food and could eat equal amounts, the manipulated flies were in poorer physical condition.

In order to mate with available females, the aging males were compelled to compete with young males. It turned out, as expected, that males in good physical condition were better at this than those who were in poorer condition, independently of how old they were. The reproductive aging of males, however, decreased at the same rate, independently of whether they were in good or poor physical form. Things were different for females. Early in life, there was no difference between the number of offspring produced by females in good condition, who could use the available resources better, and the number produced by mutated females, who were in poorer condition. The two groups, however, aged at different rates. As the females became older, those who were in good physical form had more offspring than their less fortunate sisters.

"The results show that sexual selection contributes to the differences between the sexes in reproductive aging. This is probably because females in good condition, with good access to nutrients, invest the extra resources into maintaining their bodies, such that they can continue to reproduce to a more advanced age. Males, in contrast, seem to invest a great deal of their resources, independent of their condition, into trying to ensure that they achieve successful mating here and now."

Link: https://liu.se/en/news-item/darfor-aldras-honor-langsammare

Bill Cherman and I, cofounders of Repair Biotechnologies, were recently interviewed on the topic of the Longevity Investor Network, an initiative organized by the Life Extension Advocacy Foundation volunteers. The Network is a group of angel investors and venture capitalists of varying backgrounds, all of whom are interested in the rapidly growing longevity industry. Some want to speed the advent of therapies capable of turning back aging, some are long-time fellow travelers from our broader advocacy community, some are newly arrived, just starting to learn about the science and the potential scale of this market. It is a real mix of views and motivations.

Every month a few aging-focused startup companies are presented to the network, and the gatherings are a chance to make connections and put names to faces. To an outsider it might sometimes seem that all of the behind the scenes communication in the venture community just happens automatically, with no need for effort. Nothing could be further from the truth; communication is hard, and building professional networks is an essential part of growing any industry. This is a very helpful initiative for a period in which we are striving to connect promising lines of research to commercial development groups and venture capital.

Why, generally, do you invest in longevity companies?

Reason: It is an effective means of advancing the state of rejuvenation biotechnologies that are at a certain stage of maturity. It is at least ten times easier to raise investment funding than it is to raise philanthropic funding, but there is very little difference in the use such money is put to when comparing late-stage lab work with early-stage startup work.

Venture capital and its angel community cousin like to present themselves as bold and risk-taking, but there is nonetheless an awful lot of herd behavior taking place. Investors follow for preference. A great deal can be accomplished in terms of steering money to sensible destinations by stepping out in front of the crowd and presenting a solid rationale for investment choices, by being the first to put some money down and explaining in detail why you choose to do that. It works at the level of small angel investments, and it works at the level of Jim Mellon's Juvenescence venture.

Bill: There are mission and financial motivations. Mission-wise, no industry can have a more positive impact on humanity than the longevity industry; after all, life is man's fundamental value, and all others require it. Biotech startup investing has historically delivered distinctive results to investors; if longevity startups succeed in extending healthspan, even larger financial outcomes will follow, I believe. I particularly like early-stage preclinical companies, which are often valued in the 7-, low-8-digit range and can IPO and reach unicorn status in as early as 2-3 years.

Why do you see value in having a network of investors who share and collaborate on deals?

Reason: Rare is the deal in which a network of investors was not in some way involved in bringing it about. The present ad hoc assembly of happenstance meetings, persuasion, and passage of information is an essential part of setting up companies, even if the investment is ultimately made by just a few of those participants. Formalizing the networks helps greatly in lowering the barriers to entry for entrepreneurs (there are never enough entrepreneurs) and to finding good investment opportunities on the part of investors. AngelList, I think, has proven this quite comprehensively. The same applies at any level of investment.

Ultimately, however, this is a little different from your run-of-the-mill investment where, at the end of the day, the point is to obtain more of those funny little tokens called money. Here, the goal is more life and the medical control of aging, and, at some point, the funny little tokens become a little less important than getting the job done. That dynamic is still shaking itself out, but I think we need communities whose members recognize that doing no more than aiming at increments of net worth to enable an ever-more luxurious tomb marker at some increasingly near point in the future is obsolete thinking when it comes to life science investment.

Bill: I would note there is value to investors and entrepreneurs. Investors get a more curated deal flow and a more thorough due diligence process, while entrepreneurs, many of whom lack business experience (to their benefit, many times), get access to several people who they can bounce ideas with and who can give them some guidance on fundraising, communicating with stakeholders, etc.

What do you hope the Longevity Investor Network can grow into?

Reason: A much bigger group of investors who largely understand that the point of this exercise is to generate a world in which aging can be controlled and that funding and profit are just means to an end. In a world in which money can truly buy additional health in late life, buy time spent vigorously alive, then money is somewhat less the central focus that it is today. The point becomes living, and, in this, we all win together or we all lose together. Senolytics show the way: high-tech development at the core, and a surrounding halo of cheap, highly beneficial treatments, something that will benefit the entire world as a result of early investments in the field.

Bill: Ideally, a one-stop shop for longevity startups to quickly raise money from smart and helpful investors, so they don't have to burn months of energy with fundraising and can go back to the science as soon as possible.

Link: https://www.leafscience.org/investing-in-longevity/