Chimeric Antigen Receptor T Cells as a Treatment for Fibrosis

Chimeric antigen receptor (CAR) T cell therapies are used to treat cancer, engineering T cells to be more aggressive towards cancer cells. The approach has proven quite effective in comparison to past treatments for a number of cancer types. In principle this CAR-T immunotherapy can be used to target any cell population that has distinct surface markers, not just cancer cells. Here, researchers demonstrate the ability to destroy the fibroblasts responsible for generating fibrosis in the aging heart. Fibrosis is a form of dysregulated tissue maintenance, in which cells build up scar-like deposits of collagen that degrade tissue structure and function. It is interesting to compare this with work on clearing senescent cells in heart tissue, which also reverses fibrosis. Senescence is clearly one of the factors driving fibroblasts to become overactive, most likely via the inflammatory, pro-growth signaling produced by senescent cells, rather than via fibroblasts becoming senescent in large numbers.

Heart disease is the leading cause of death in the United States, and excessive cardiac fibrosis is an important factor in the progression of many forms of heart disease. It develops after chronic inflammation or cardiac injury, when cardiac fibroblasts - cells that play an important role in the structure of the myocardium, the muscular middle layer of the heart's wall - become activated and begin to remodel the myocardium via extracellular matrix deposition. Research has shown that the removal of activated cardiac fibroblasts can reduce heart stiffness, making it easier for the ventricles to relax. However, there are no therapies that directly target excessive fibrosis, and very few interventions have shown the ability to improve heart function and outcomes among patients with impaired cardiac compliance.

As a first step, researchers launched a genetic proof-of-concept experiment using mice that can express an artificial antigen (OVA) on cardiac fibroblasts. The mice were treated with agents to model hypertensive heart disease, a condition associated with left ventricular hypertrophy (enlargement or thickening of the heart walls), systolic and diastolic dysfunction (pumping of blood in and out of the heart), and widespread cardiac fibrosis. To selectively target the OVA proteins expressing cardiac fibroblasts, the team treated one cohort of mice with engineered CD8+ T cells that express a T-cell receptor against the OVA peptide. At the four-week mark, the mice who were treated with the reengineered cells had significantly less cardiac fibrosis, whereas the mice in the control groups still had widespread fibrosis.

After establishing the feasibility of this approach, researchers sought to identify a protein specifically expressed by activated fibroblasts that they could program the genetically modified T cells to recognize and attack. Using an RNA sequence database, the team analyzed gene expression data of patients with heart disease and identified the target: fibroblast activation protein (FAP), a cell surface glycoprotein. Researchers then transferred engineered FAP CAR T-cells into mice at the one and two week marks, aiming to target and deplete FAP-expressing cardiac fibroblasts. Within a month, researchers saw a significant reduction of cardiac fibrosis in the mice that were treated with the engineered cells, as well as improvements in diastolic and systolic function.


A Rapid Process for Senolytic Drug Discovery

In Silico Medicine specializes in the application of computational methods to speed up the process of screening small molecule drugs, while reducing the costs, an advance in infrastructure technology that is very much in favor these days. Most of the large entities in medical development still proceed exactly has they have done for decades in the matter of developing new therapies: find a molecular target, then find a small molecule that influences that target, then iterate over variations to try to increase efficacy and reduce side-effects. Thus numerous groups work in this part of the field, trying to cut presently sizable costs and improve the presently poor odds of success. In this paper, the In Silico Medicine team demonstrates that they can very rapidly identify candidate small molecule senolytic drugs, capable of clearing the senescent cells that contribute to aging and age-related disease.

A team of researchers has succeeded in using Artificial Intelligence to design, synthesize and validate a novel drug candidate in just 46 days, compared to the typical 2-3 years required using the standard hit to lead (H2L) approach used by the majority of pharma corporations.

By using a combination of Generative Adversarial Networks (GANs) and Reinforcement Learning (RL), the team of researchers behind this study (documented in a paper published this month) have succeeded in validating the real power that AI has to expedite timelines in drug discovery and development, and to transform the entire process of bringing new drugs to market from a random process rife with dead ends and wrong turns to an intelligent, focused and directed process, that takes into account the specific molecular properties of a given disease target into account from the very first step.

Researchers have long advocated for the extreme potentials that AI has in terms of making the process of discovering and validating new drugs a faster and more efficient process, especially as it pertains to aging and longevity research and the development of drugs capable of extending human healthspan and compressing the incidence of age-related disease into the last few years of life. While this is the newest in a long line of steps and accomplishments aiming to turn the theoretical potentials of AI for longevity research into practice, it is also the largest step made thus far, and goes a very long way in terms of proving that potential via hard science.


Arguing for Extracellular Vesicles to Mediate Beneficial Effects of Parabiosis

Cells communicate with one another constantly, and a large portion of that communication is not carried by individual secreted molecules, though there are certainly a lot of those, but rather takes the form of small membrane-bound packages of diverse molecules known as extracellular vesicles. Cells generate and secrete extracellular vesicles of various sizes, and other cells ingest them. Two important areas of active research into cell signaling are the way in which young tissue can restore the function of old cells, and the way in which senescent cells change the activity of surrounding cells for the worse. In both cases, extracellular vesicles are important in this process of communication and influence.

There is a substantial faction in the research community focused on potentially beneficial effects that derive from young blood, emerging from the study of heterochronic parabiosis in which the circulatory systems of a young and old mouse are linked. The old mouse benefits and shows some signs of reversal of the consequences of aging, the young mouse exhibits accelerated signs of aging. Is this in fact due to beneficial signals in young blood? There is good evidence that strongly supports the case that benefits result from a dilution of harmful factors in old blood, and that beneficial factors in young blood are not important. Nonetheless, there is further independent evidence in which factors or extracellular vesicles derived from young blood have been used to produce benefits in old mice. There are also a number of failures to show meaningful benefits from blood or plasma transfusion, in mice and humans. It is an interesting field, in which conflicting evidence abounds.

Extracellular vesicles circulating in young organisms promote healthy longevity

In the late 1950s, parabiosis experiments provided some scientific consistency to these beliefs. Indeed, a shared circulatory system was sufficient to increase bone weight and density of old mice when joined to younger ones. The same experimental design was applied to demonstrate a lifespan-enhancing effect of young blood. Many years later, elegant reports demonstrated a rejuvenation-promoting effect of young blood in a wide variety of cells and tissues, e.g. stem cells, muscle, brain, and the heart. However, the pursuit of the circulating factors responsible for such effects did not achieve the same success. In fact, the suggested pro-regeneration role of growth differentiation factor 11, a member of the TGFβ superfamily, has been questioned.

Extracellular vesicles (EVs) are membrane-coated nanoparticles actively released by almost all cell types. Increasing evidence indicates that both are able to shuttle and deliver functional proteins and nucleic acids in a paracrine and systemic manner. Blood contains a heterogeneous mixture of EVs of different origins, which are currently being characterized for therapeutic and diagnostic purposes. The effects of EVs are now attracting intense interest also in the context of ageing and age-related diseases (ARDs).

In particular, senescent cells (SCs) are emerging as major drivers of ageing and key contributors to inflammaging, the age-associated pro-inflammatory drift that promotes the development of ARDs. Recent evidence suggests that EVs are also central constituents of the SCs secretome. In particular, SCs secrete an increased amount of EVs, excreting pro-inflammatory DNA and possibly spreading pro-ageing signals. Conversely, a seminal paper suggests that a 4-month injection of small EVs derived from hypothalamic neural stem cells and rich in specific miRNAs into the hypothalamic third ventricle is sufficient to ameliorate some age-associated detrimental outcomes in C57BL/6 mice, including hypothalamic inflammation and the drop in physical activity.

These and other observations prompted the hypothesis that EVs are central mediators of the circulating communicosome fostering inflammaging. In that framework, we hypothesized that the chronic administration of EVs purified from a young healthy mouse to an old one should ameliorate some age-associated phenotypes. This experimental approach appeared to be enough feasible and robust to demonstrate a tangible role of EVs in the ageing process. Researchers have now shown a clear pro-longevity role for EVs isolated from young mouse plasma. Indeed, they injected EVs isolated from 4-to-12-month-old mice into 26-month-old female mice once a week until sacrifice and observed an increase of 10.2% and of 15.8% in median and maximal lifespan, respectively, in mice receiving the treatment vs. vehicle-treated mice of the same age.

Controlling Hypertension Slows Cognitive Decline

The study here shows that given a population of individuals with hypertension, those who manage to control their high blood pressure go on to suffer lesser degrees of cognitive decline. Numerous mechanisms may link hypertension to structural damage in the brain: degeneration of the blood-brain barrier, allowing inappropriate molecules and cells into the brain, leading to neuroinflammation and other effects; rupture of capillaries causing microbleeds, effectively tiny strokes; outright pressure damage in tissue very close to small vessels that directly harms brain cells; and so forth. This damage adds up, but note that it is a set of physical issues that stem from increased pressure rather than the biochemistry that causes that increased pressure. Therefore these downstream issues can be suppressed by any method that reduces blood pressure consistently, even though that will leave the underlying damaged biochemistry to continue to cause other issues.

High blood pressure appears to accelerate cognitive decline among middle-aged and older adults, but treating high blood pressure may slow this down, according to a preliminary study. According to the American Heart Association's 2017 Hypertension Guidelines, high blood pressure affects approximately 80 million U.S. adults and one billion people globally. Moreover, the relationship between brain health and high blood pressure is a growing interest as researchers examine how elevated blood pressure affects the brain's blood vessels, which in turn, may impact memory, language, and thinking skills.

In this observational study, the researchers analyzed data collected on nearly 11,000 adults from the China Health and Retirement Longitudinal Study (CHARLS) between 2011-2015, to assess how high blood pressure and its treatment may influence cognitive decline. High blood pressure was defined as having a systolic blood pressure of 140 mmHg or higher and a diastolic blood pressure of 90 mmHg or higher, and/or taking antihypertensive treatment. According to guidelines of the American Heart Association, high blood pressure is defined as 130 mmHg or higher or a diastolic reading of 80 mmH or higher.

Researchers interviewed study participants at home about their high blood pressure treatment, education level, and noted if they lived in a rural or urban environment. They were also asked to perform cognitive tests, such as immediately recalling words as part of a memory quiz. Among the study's findings: (a) Overall cognition scores declined over the four-year study; (b) Participants ages 55 and older who had high blood pressure showed a more rapid rate of cognitive decline compared with participants who were being treated for high blood pressure and those who did not have high blood pressure; (c) The rate of cognitive decline was similar between those taking high blood pressure treatment and those who did not have high blood pressure.


Lipid Turnover in Fat Tissue Decreases with Age

Researchers here show that lipid turnover in fat tissue decreases with age, and suggest that this mechanism explains some fraction of the tendency to gain weight with age. Everyone of a certain age recognizes that it takes ever more effort to evade or get rid of excess fat tissue. It remains an open question as to which underlying mechanisms cause this change in lipid turnover, though given progress in rejuvenation research we are at the point of being able to test hypotheses such as chronic inflammation resulting from senescent cells, or mitochondrial dysfunction. We shall see what new data on this topic emerges in the years ahead.

Scientists studied the fat cells in 54 men and women over an average period of 13 years. In that time, all subjects, regardless of whether they gained or lost weight, showed decreases in lipid turnover in the fat tissue, that is the rate at which lipid (or fat) in the fat cells is removed and stored. Those who didn't compensate for that by eating less calories gained weight by an average of 20 percent, according to the study.

The researchers also examined lipid turnover in 41 women who underwent bariatric surgery and how the lipid turnover rate affected their ability to keep the weight off four to seven years after surgery. The result showed that only those who had a low rate before the surgery managed to increase their lipid turnover and maintain their weight loss. The researchers believe these people may have had more room to increase their lipid turnover than those who already had a high-level pre-surgery.

"The results indicate for the first time that processes in our fat tissue regulate changes in body weight during ageing in a way that is independent of other factors. This could open up new ways to treat obesity." Prior studies have shown that one way to speed up the lipid turnover in the fat tissue is to exercise more. This new research supports that notion and further indicates that the long-term result of weight-loss surgery would improve if combined with increased physical activity.


Matthew O'Connor Presenting on Underdog Pharmaceuticals at Undoing Aging 2019

Here Matthew O'Connor of the SENS Research Foundation talks about the research that led to founding of Underdog Pharmaceuticals, a biotech startup incubated by the foundation to commercialize a means of targeting 7-ketocholesterol in atherosclerosis and other conditions. Oxidized cholesterols, and largely 7-ketocholesterol, are the primary cause of dysfunction in the macrophage cells normally responsible for preventing the build up of fatty plaques in blood vessel walls. That dysfunction is the cause of atherosclerosis, and the fact that the presence of oxidized cholesterols increases with age is one of the reasons why atherosclerosis is an age-related disease, and why young people don't exhibit the plaques that narrow and weaken blood vessels.

A sufficiently effective way of selectively clearing 7-ketocholesterol from the body should go a long way towards preventing and reversing atherosclerosis - and possibly other conditions as well. As noted here, there is evidence for 7-ketocholesterol to accumulate in other tissues and contribute to age-related conditions in other ways. The particular approach taken by the SENS Research Foundation scientists is to find a non-toxic molecule that selectively binds to the toxic molecule that one would like to remove, 7-ketocholesterol in this case, and deliver it to the body in volume. The bound molecules are then processed and excreted in the normal way. It will be interesting to see how the Underdog project progresses in the years ahead.

Matthew O´Connor presenting at Undoing Aging 2019

Thank you everybody. It is a real honor and a pleasure to be here today, speaking in a last minute slot. Don't volunteer to take over to speak for someone who didn't show up, because then you have to stay up all night, working on your slides. This slide is the SENS team from this last summer, a combination of the MitoSENS team and the team working on 7-ketocholesterol that Aubrey de Grey was just referring to, that we're calling the Underdog team. You can see me as the chief Underdog there.

I want to just spend a minute, Aubrey had mentioned that this is the tenth anniversary of SENS Research Foundation, and it is my 9th year with SENS Research Foundation. It has been a privilege to have started so early, to help build the lab, and I wish that I could show a time lapse photography of where it started and where it has gone, and also to be involved with some of these amazing interns. So many of these projects, including this one, are very intern driven. Regarding the MitoSENS team, people may not realize that all the progress Aubrey was talking about, publishing papers all of a sudden, didn't happen until after we hired Amutha, so you can see why that project got taken away from me and given to her. She is just a phenomenal mitochondrial biologist.

So this project that I'm about to tell you about involves a story about 7-ketocholesterol. I hope that a lot of you have heard about it. It is kind of one of the classic bad guy molecules that Aubrey has been talking about for a long time. My history with it goes back even further than SENS Research Foundation, as the foundation and Methuselah Foundation before it have been funding work on trying to get rid of this really nasty molecule 7-ketocholesterol for at least ten years, with work that we've funded in various places. I actually heard Aubrey give a talk about this, one of the best talks I've ever seen, at Rice University something like 15 years ago when I was in graduate school. So I've been thinking about it ever since then.

This project kind of started out as some ideas about how to think about this problem and how to get rid of this nasty molecule a different way. It started out as something that we were sort of dabbling in, and graduated from being my 20% project to something that is all-consuming now. On this slide, you can see causes of death worldwide, which probably looks familiar to you many of you. As Aubrey was just saying, atherosclerosis is the world's biggest killer. If you risk-adjust all of these diseases for what their underlying cause is, atherosclerosis is believed by world health organizations to kill about 44% of everybody. This molecule, 7-ketocholesterol, an oxidized form of cholesterol, is thought to be one of the earliest stages leading to atherosclerosis. But not everyone simplistically believes in that model; the classic model is that you eat too many hamburgers and you get too much cholesterol in your bloodstream, and that just sort of stochastically builds up, and eventually you get plaques, and eventually they rupture and you have heart attacks and strokes, and you die.

However 7-ketocholesterol is many, many, many times more toxic than LDL cholesterol is - so I call it the really bad cholesterol. It is by far the most common product of the reaction between a free radical and cholesterol, and so more often than not you get this stable 7-ketocholesterol which is extremely toxic. It has no useful purpose in your body. It can accumulate in the lysosomes of macrophages and can be an early step in the progression towards becoming a foam cell. Foam cells build up as a layer in atherosclerotic plaques, and 7-ketocholesterol is found inside them, as well as in the necrotic core of the plaque.

Let me change gears now and reveal the class of drug, the class of molecules, that we have been playing around with for the last few years. They are called cyclodextrins. You may or may not have heard of them, but they are a huge industry, and they have a huge variety of applications. The medical applications, despite the fact that cyclodextrins have been studied and applied for many decades, are only just starting to be realized. They come in three basic flavors, alpha, beta, and gamma, which are three different sizes, and they have six, seven, or eight different sugar rings that they are made out of. There are different forms of them, probably thousands of different ones that have been invented. They are extremely customizable and modifiable. Any one of these hydroxyl groups you can stick just about anything you want on it, doing synthetic chemistry.

The slide here shows just a few examples of common cyclodextrins that are used for various industrial purposes. Medically, they are mostly now only used as excipients, meaning as carrier molecules for small hydrophobic drugs. They are used in food: alpha-cyclodextrin is approved in the European Union as a bulk fiber supplement, so maybe you ate some of it this morning. There are versions of these that are extremely low toxicity household items, like Febreze. People can use cyclodextrins, use different formulations of them mixed with other guest molecules that stick into the cyclodextrin cavity, to engineer all kinds of materials such as self-healing gels. They look like jello, and you cut it in half and put it back together and there is no seam any more. Somebody in Japan built a car out of cyclodextrins, and there is a German scientist who is making self-healing paint for cars.

Now let me summarize a bit the history of using cyclodextrins themselves as the active component of drugs. That is what we're trying to do here, to engineer them to be drugs to target 7-ketocholesterol directly. The history here goes back to the 1990s, where this Australian group had a lot of foresight; they already knew that 7-ketocholesterol was a really toxic atherogenic molecule back then, this isn't a new discovery. There has been tons of evidence for that for decades. Cyclodextrins were just starting to be explored in the 80s and 90s as cholesterol binding drugs; different versions of them bind cholesterol well. So they went looking for a modified cyclodextrin that can specifically bind 7-ketocholesterol with a hypothesis, and they found hydroxpropyl-beta-cyclodextrin, which I will tell you about. After they published a bunch of papers, however, they abandoned it and never went into any animal studies.

However, there was a group in Texas that seems to have picked up on this idea, and there was an orphan disease called Niemann-Pick type C, which is a lysosomal storage disease, that hyperaccumulates 7-ketocholesterol. These patients, almost always children, are very sick and die very young. There are good mouse and cat models for this disease, and if you dose them with very high doses of hydroxpropyl-beta-cyclodextrin, you can rescue the small animals. People have started to look at this for atherosclerosis because hydroxpropyl-beta-cyclodextrin is so safe, but there is some debate as to whether you are targeting 7-ketocholesterol, and I'll present some evidence as to why I'm strongly in favor of one hypothesis over the other. For the Niemann-Pick studies, it is going into clinical trials, it is entering phase II, there is a lot of funding going into this now. Presumably because they've got their eyes on atherosclerosis rather than just Niemann-Pick, which is an extraordinarily rare disease.

This slide shows some older data on cyclodextrin, and this came from the Australians. They are soluablizing 7-ketocholesterol, and here is the effect that it has on cholesterol, which is to say nothing, while it does a great job soluablizing 7-ketocholesterol. I'm going to talk a lot about this assay, so if you don't understand it, hold tight and I'll explain it in more detail. 7-ketocholesterol is very toxic, so with increasing doses you kill cells in culture and this was work we funded at Rice University, kind of as a scientific control for the experiments that they were doing. They were playing with cyclodextrin; as I said, it has a lot of different functions. They were using it as a carrier molecule, and found that it was working better than anything else that they were using, while we were working on the earlier LysoSENS enzymatic process to rescue the cells from 7-ketocholesterol toxicity. Then more recently, work in that same lab led to a paper and a patent on the idea of using that same cyclodextrin to prevent and reverse lipofuscin from forming in cells.

So I'll leave that there as history and show you this happy and sad video of cats with Neimann-Pick disease. All three of these cats have this disease and their phenotype is pretty similar to that of the humans. It is a devastating disease. All of these cats have it, one of these cats has been treated with hydroxpropyl-beta-cyclodextrin at a very high dose. Apparently this video is famous in the FDA for how you get something fast tracked into humans by showing a heart-tugging video like this. Because it clearly is working very dramatically to help these cats.

This slide shows the assay that we use. It is a really simplistic assay to screen through many different compounds, the many different cyclodextrins, many different modifications to cyclodextrins that we've made. It is a simple turbidity assay that we've automated. If you dump most sterols that are not water soluable into an aqueous solution, they get cloudy. Then if you managed to add something to the solution that can soluablize the sterols, then the solution turns clear. That is an indication that they are binding to your target.

So we've automated it, you run many of these plates, read them in a plate reader, and you get data that looks like this next slide. I'm just reporting the percent turbidity, so start at 100% and then go down, or in some cases it becomes more cloudy. So these are some cyclodextrins that have been studied for Neimann-Pick disease, as I keep talking about, hydroxpropyl-beta-cyclodextrin is one of our favorites. It doesn't bind cholesterol, even at ridiculously high concentrations. With 7-ketocholesterol it has nice specificity. There's another one, sulphobutyl, that has also been tested somewhat in animal models for Neimann-Pick disease but hasn't really gone further than that, and doesn't seem to be as effective as hydroxpropyl-beta-cyclodextrin.

The safety profile for some cyclodextrins such as hydroxpropyl-beta-cyclodextrin is just phenomenal. It is much less toxic than aspirin, or something like that. So you can dose humans or animals with grams of it and they are fine. As you can see, hydroxpropyl-gamma-cyclodextrin, a bigger one, doesn't do anything in the assays.

We've checked many different cyclodextrins and run them through our screening process. This slide shows a bunch more from the catalogs. Some of them are better and some of them are worse. The point of showing this to you is to show how we gathered a ton of data about which cyclodextrins were interacting with which targets in which ways, and I deleted a whole bunch of data because I was practicing this this morning, and I had too much in the presentation. But we also screened a bunch of other targets, other sterols that you can order from the Sigma catalog. That helps us look at off-target effects.

We can also do it computationally. On this slide you see the former intern that Aubrey was bragging about before. She had the idea when she was an intern - we were already working on this project, and making some progress, and she said well why don't you just model them, you can learn so much about them. She said I'll figure it out. So now she's one of the world's experts in modeling cyclodextrins. Which is a very niche field. Only a few people in the world know how to do this.

What you see here is a molecular dynamic simulation of just a basic beta-cyclodextrin. We've done hundreds of different simulations on different tweaks and different cyclodextrins, mostly with just cholesterol and 7-ketocholesterol, trying to optimize selectivity binding. Also to optimize the affinity. So beta-cyclodextrin, just the core molecule, is known as a good cholesterol binding molecule, but we can learn additional things here. If you stick it in this way, both cyclodextrin and cholesterol are asymmetrical molecules and if you start with it the wrong way, it will go in the way that it prefers. It seems kind of nitty-gritty to talk about, but that kind of information is what helped us figure out all the different subtle ways in which cyclodextrins are binding their targets.

Now on this slide is a model of hydroxpropyl-beta-cyclodextrin binding 7-ketocholesterol extremely tightly and with specificity. To really get the lowdown on this, and this is all unpublished data, we'll have a publication coming out soon, that we're furiously writing now. Go see the posters at this conference, and grill me on this, because the author is brilliant, she's great at explaining it. So we started optimizing cyclodextrins, making little tweaks to them, and came up with some tricks on how to improve the affinity for them, starting out with hundreds of these models. This slide shows the kind of data you'll get from it, the geometry of how they are interacting, how closely in space they are interacting. Then the information, that I think is the most dramatic, about the affinity.

So when you find one that is actually going to grab on super-tightly, then you massively increase the free energy of interaction, or decrease it. You can see that this also corresponds with super-close, tight, and stable interaction between the two molecules. Those kinds of simulations are extremely high resolution. We do them for a whole microsecond, which is an eternity in terms of nanosecond resolution simulations of molecules. The chief way to do lots of simulations is to do molecular docking, and so using this method - this slide is, I think, 28 different simulations that are done quickly, doing just small little tweaks to a particular family of cyclodextrins. We look for areas such as here where you seem to get separation between cholesterol and 7-ketocholesterol.

That is what led us to the step shown on this slide, which is that we synthesized some new cyclodextrins and checked to see if they could increase their affinity and maintain specificity for 7-ketocholesterol. Up at the top here you have hydroxpropyl-beta-cyclodextrin, which doesn't bind cholesterol, it binds 7-ketocholesterol a little bit. However, note the change in scale down here, we're using lower dosing ranges. The modifications that we're making to these that I'm showing you here today, they all work phenomenally well to massively increase the affinity for our target 7-ketocholesterol. However, all of them also increase their affinity for cholesterol. You probably can't see all of them in this slide, but some of them are maintaining better specificity than others, and those are the ones we're most excited about.

So there are a couple of different families of new cyclodextrins that we've invented that have extremely high affinity for 7-ketocholesterol. One in particular that caught our eye that we're really excited about - again, hydroxpropyl-beta-cyclodextrin up here at the top of the slide, some nice specificity for 7-ketocholesterol. Down here, one of the new cyclodextrins that we made has an extremely high affinity for 7-ketocholesterol, and good specificity.

Like I was saying before, these are exciting molecules to work on because they are really safe, the different versions are edible, breathable, or injectable, as in happening in the Neimann-Pick trials. A classic safety test before going in vivo is to collect some blood from whatever hapless CEO or intern happens to be wandering down the wrong time, and then treat their blood with something, and if it lyses it, then it is killing their blood cells, and if it stays clear then it is not. All of the new cyclodextrins that we've made seem to be non-toxic in the pharmacological range, and as you go above that you get some variation. For the one we're most excited about, that had the highest specificity for 7-ketocholesterol, we couldn't find a dose at which we would kill any blood cells.

I'm going to try to make the case that animal models for atherosclerosis are useless, and that we should skip straight to humans. My argument is that mice, rodents, don't get atherosclerosis naturally, and when you do give it to them by knocking out their ability to metabolize cholesterol, they are just not able to take up cholesterol, to clear it, so that it just builds up into artificial plaques. We don't think that is a good model. So once again we're working in humans, we're stealing their blood, and then treating blood with the drug in concentrations that we think are realistic and for time periods that we think are realistic. We know a lot - so much work has been done on safety for cyclodextrins over the years. We know a lot about how quickly it is cleared from circulation in different animal systems and even humans.

Then what we're doing is instead of trying to measure serum 7-ketocholesterol levels, which basically don't exist, as 7-ketocholesterol isn't transported in HDL or LDL, and that is part of what makes 7-ketocholesterol so toxic, as it can't be transported out of cells. We're measuring our ability to release 7-ketocholesterol into the serum, and measuring it by mass spectrometry. The early data on our new cyclodextrins is looking good. In this slide here is hydroxpropyl-beta-cyclodextrin that can remove some 7-ketocholesterol from human blood cells, and the first new cyclodextrin that we made can do a lot more, a lot better, and with blood from multiple donors.

So to recap, there are some big players in this area that are excited about being able to treat an orphan disease like Neimann-Pick disease. They probably have their eyes on going after bigger indications like heart disease, but they think that they are treating cholesterol, which I think is crazy. I think that they are actually treating 7-ketocholesterol, and that they are having the success that they are having because of this. However our drug blows it away in terms of affinity for the target by something like tenfold.

Beyond atherosclerosis, 7-ketocholesterol is implicated in a number of diseases, as shown on this slide. It is one of those bad guys that accumulates in different tissues with age, and we don't even know yet everything that it is implicated in. Just as for senescent cells now that people are finding ways to kill them, all of a sudden you are finding aspects of aging that are being reversed when you kill senescent cells, and I predict that someday we'll see the same thing with 7-ketocholesterol. However, atherosclerosis and heart failure I think are great indications. Of course familial hypercholesterolemia is just an exaggerated way to get atherosclerosis. There is Neimann Pick disease, and we think are drug would work better than the ones that are out there now.

I don't want to try to claim that 7-ketocholesterol causes everything that has ever made everyone sick, but it does accumulate in macular degeneration and some cells in Alzheimer's disease. Our tools that we've developed to make new cyclodextrins, to test them, to model them, I think that this is a great platform. There are other toxic oxysterols that we could be going after that we haven't starting working on yet, but are good targets for this kind of technology. Basically any small hydrophobic molecule that is bioaccumulating is a potential target. So the space in this area looks crowded because there are tens of thousands of patents on cyclodextrins, however when you get down into using cyclodextrins as drugs themselves, then you are down into single digits, like four or five patents that are out there. So we think that we have pretty strong data and protections that will get there.

Because cyclodextrins have such a good regulatory profile and are so well established in how you can use them safely, industrially, in food, in medicine, we think that the pathway to turning this into an actually effective drug - that we can write a plan, and have it be realistic is good. We're talking to experts on formulation and manufacturing, and what you see on this slide are realistic timelines. We're developing some more assays that we think will be more effacious; assays that will demonstrate that we can reverse a foam cell phenotype for example, or remove 7-ketocholesterol from plaque samples that we're working on getting from human patients or cadavers. So we have a detailed month by month plan on how we think that we could get a drug to clinical trials in three years.

As Aubrey said, we're working and making great strides on turning this into a SENS Research Foundation spinout, wholly incubated and owned at the foundation. We're calling it Underdog Pharmaceuticals.

An Interview with Aubrey de Grey at Longevity.Technology

It is always pleasant to see new efforts to produce longevity-focused interest sites and publications; Longevity.Technology is a recent example, here publishing an interview with Aubrey de Grey of the SENS Research Foundation that touches on recent developments in the field of rejuvenation research. There have been many such news organization initiatives over the past ten to fifteen years, and all too few of them lasted. Hopefully that will change now that an industry of rejuvenation is forming, beginning with the development of senolytic therapies, and ever greater degrees of funding and attention are directed towards this part of the life science field. If we look at larger fields, enough of that funding and attention can spill over to support a community focused on analysis, reporting, and other such work. That should happen here as well.

We've read a lot of very compelling reasons from you as to why we as a society should care about aging, but we're very curious what made you care about it?

Nothing really made me care about it. It was always obvious to me that it was the number one most important problem in the world. It's the thing that causes by far the greatest amount of suffering and everyone gets it. The astonishing thing was that other people didn't think that way. In fact, I only discovered that others didn't in my late 20s. I had gone through my entire life presuming that it was as obvious as the colour of the sky. It wasn't something I would even have conversations about, so I'd never done the experiment to determine whether anyone else agreed. Then I met my ex-wife, who was quite a senior biologist at the time. And I began to discover that, actually, people didn't think that way, not even in biology. And hardly any work was being done to deal with this problem. So I thought "Well, that won't do."

What is the SENS platform and why did you need to create it?

SENS stands for Strategies for Engineered Negligible Senescence. It's a formal name for the way my organisation, the SENS Research Foundation, develops therapies for the diseases and disabilities of aging. I was able to see that there was indeed a very different, and entirely overlooked, approach to dealing with aging. And it was something the people who were studying it weren't doing: that we should essentially be trying to repair damage in the body. When I'm feeling frivolous, I like to compare gerontologists of that era to seismologists. What they studied was bad for you, but they had no idea whatsoever how they could actually do anything about it. I stuck to my guns, stood my ground and people have gradually caught up and understood the kinds of things I've been saying all the time. Now it's totally mainstream - orthodox - and people are reinventing the idea in slightly different language. So that's all very nice.

What undeveloped areas are you working on at the moments?

One that really is a centrepiece project in-house (and has been for quite some time) is to put back-up copies of the mitochondrial DNA in the cell nucleus. For non-biologists who are reading, mitochondria are very essential parts of each cell that perform the chemistry of breathing. They combine oxygen with nutrients in order to extract energy from those nutrients. And, unlike any other part of the cell, the mitochondria have their own DNA - separate from the DNA of the nucleus.

But the process of extracting energy from nutrients using oxygen is chemically hairy, producing a load of by-products (in particular free radicals) that can damage the mitochondrial DNA and give it a really bad day. So the idea that we've taken, that was put forward in the mid 80s, is to essentially put copies of the mitochondrial DNA inside the nucleus, modified so that it still works in there, to shield it from this damage. It's not as hard as it sounds, but it still is very hard! People gave up on it ... they thought it was too hard. I thought that they'd given up a bit too easily. And it turns out I was right - we had to work about ten years or so before we eventually got to the point of being able to publish a single paper on this. But we eventually got there a couple of years ago, and now we have a second paper in the works demonstrating that we have done most of the job.


The Longevity Associated Variant of BPIFB4

In principle, genetic variants associated with longevity should help to point out which processes are more important in the aging process, and therefore steer researchers towards more effective approaches to interventions aimed at slowing or reversing aging. In practice, however, so few longevity-associated variants have been found that little has been accomplished on this front. One of them is examined in this open access paper. The mechanism by which it contributes to longevity may be a reduction in the burden of hypertension and consequent tissue damage.

To be clear, near any study of genetics and aging turns up all sorts of variants that correlate with longevity in the study population in question, but only a handful have ever been replicated in other study populations. This tells us that the genetics of aging is a matter of hundreds or thousands of tiny, interacting contributions, highly sensitive to environmental factors. This is why I am not optimistic that genetic studies of this nature are the road to any sort of meaningful progress towards greater human longevity. Even the variant here, if it operates via a lowering of blood pressure, is a poor substitute for long-standing drugs that achieve the same result to a greater degree, and those drugs were developed without any reference to the genetic study of longevity.

Frailty reflects the individual's biological age and life expectancy better than chronological age. Studies in long-living individuals (LLIs), which, in spite of their exceptional biological age, are protected from and cope better with age-related diseases, confirm this concept. Moreover, several genetic factors that are reportedly implicated in the determination of exceptional longevity are also inversely related with frailty disabilities.

The Bactericidal/Permeability-Increasing Fold-Containing Family B member 4 (BPIFB4) gene encodes a secreted protein, initially found to be expressed in salivary glands, and more recently discovered to play important pathophysiological roles at systemic level. A genome wide association study (GWAS), performed on an Italian set of LLIs and controls and validated on two independent populations from Germany and USA, identified the BPIFB4 variants associate with lifespan.

The BPIFB4 protein is expressed in undifferentiated and highly proliferative cells and in fetal/stressed heart tissue (cardiac hypertrophy), which share a common hypoxic environment. Overexpression of BPIFB4 isoforms induced the activation of stress response-related heat-shock proteins (HSPs) and the modification of protein homeostatic processes (translation, ribosome biogenesis, spliceosome), two processes that are usually lost during aging.

Furthermore, the circulating levels of immunoreactive BPIFB4 protein are reportedly higher in healthy LLIs than in diseased LLIs or young controls. Similarly, CD34+ hematopoietic cells and mononuclear cells (MNCs) of LLIs expressed higher levels of BPIFB4 than corresponding cells of young controls. Studies in experimental models of cardiovascular disease confirmed that overexpression of the human LAV-BPIFB4 gene results in attenuation of hypertension, atherosclerosis, and ischemic disease, which are hallmarks of aging.


Embedded 3D Printing Used to Assemble Tiny Organoids into Larger Vascularized Tissue Masses

For as long as I have been watching progress in tissue engineering, the primary and most important barrier to building organs to order has been the inability to construct vascular networks. A network of capillaries must exist for blood, and thus nutrients and oxygen necessary to cell survival, to reach more than a few millimeters into a tissue. In live tissues, hundreds of minuscule capillaries pass through every square millimeter, considered in cross-section. Replicating this level of capillary density in engineered tissue has yet to be accomplished, with even the more advanced technology demonstrations falling well short of this goal.

Well funded initiatives such as the effort to produce genetically engineered pigs with organs that can be decellularized for transplantation into humans, or the application of decellularization to donor human organs, should be considered as attempts to work around the vascular challenge. That is why they exist. If a suitable vascular network cannot be produced from scratch, then the existing vascular network in an existing organ is the only viable alternative. It remains to be seen as to how long these approaches will be needed, how long it will take the research community to be able to grow larger tissues with sufficient vascular networks for practical use in medicine.

As the research community continues to wrestle with the production of vascular networks, scientists have become ever more proficient in the production of small sections of organ tissue from the starting point of a cell sample, known as organoids. Given the ability to reprogram patient cells into induced pluripotent stem cells, which can then be used to produce cells of any type, building functional organoids only requires a suitable protocol: the right signals and conditions to convince cells to form tissue as they do in the body. Discovering how to do this for the more important internal organs has proceeded apace over the past decade: livers, kidneys, lungs, the thymus, and more. As soon as a viable approach to vascularization of tissue emerges, scaled up and fully functional organs made to order will soon follow.

Sacrificial ink-writing technique allows 3D printing of large, vascularized human organ building blocks

Artificially grown human organs are seen by many as the "holy grail" for resolving the shortage of donor organs for transplant, and advances in 3D printing have led to a boom in using that technique to build living tissue constructs in the shape of human organs. However, all 3D-printed human tissues to date lack the cellular density and organ-level functions required for them to be used in organ repair and replacement. Now, a new technique called SWIFT (sacrificial writing into functional tissue) overcomes that major hurdle by 3D printing vascular channels into living matrices composed of stem-cell-derived organ building blocks (OBBs), yielding viable, organ-specific tissues with high cell density and function.

"This is an entirely new paradigm for tissue fabrication. Rather than trying to 3D-print an entire organ's worth of cells, SWIFT focuses on only printing the vessels necessary to support a living tissue construct that contains large quantities of OBBs, which may ultimately be used therapeutically to repair and replace human organs with lab-grown versions containing patients' own cells."

SWIFT involves a two-step process that begins with forming hundreds of thousands of stem-cell-derived aggregates into a dense, living matrix of OBBs that contains about 200 million cells per milliliter. Next, a vascular network through which oxygen and other nutrients can be delivered to the cells is embedded within the matrix by writing and removing a sacrificial ink. "Forming a dense matrix from these OBBs kills two birds with one stone: not only does it achieve a high cellular density akin to that of human organs, but the matrix's viscosity also enables printing of a pervasive network of perfusable channels within it to mimic the blood vessels that support human organs."

Biomanufacturing of organ-specific tissues with high cellular density and embedded vascular channels

Engineering organ-specific tissues for therapeutic applications is a grand challenge, requiring the fabrication and maintenance of densely cellular constructs. Organ building blocks (OBBs) composed of patient-specific-induced pluripotent stem cell-derived organoids offer a pathway to achieving tissues with the requisite cellular density, microarchitecture, and function. However, to date, scant attention has been devoted to their assembly into 3D tissue constructs.

Here, we report a biomanufacturing method for assembling hundreds of thousands of these OBBs into living matrices with high cellular density into which perfusable vascular channels are introduced via embedded three-dimensional bioprinting. The OBB matrices exhibit the desired self-healing, viscoplastic behavior required for sacrificial writing into functional tissue (SWIFT). As an exemplar, we created a perfusable cardiac tissue that fuses and beats synchronously over a 7-day period. Our SWIFT biomanufacturing method enables the rapid assembly of perfusable patient- and organ-specific tissues at therapeutic scales.

Evidence for an Intestinal Origin of Parkinson's Disease

As is the case for many neurodegenerative conditions, Parkinson's disease is associated with the spread of protein aggregation. Specific proteins become changed in ways that cause them to form solid deposits, surrounded by a halo of associated toxic biochemistry that harms neurons. The aggregates in Parkinson's patients are formed from α-synuclein, and here, researchers provide evidence for the origins of α-synuclein related neurological dysfunction to begin in the intestine, and only later migrate to the brain.

Parkinson's disease is characterised by a slow destruction of the brain due to the accumulation of the protein alpha-synuclein and the subsequent damage to nerve cells. The disease leads to shaking, muscle stiffness, and characteristic slow movements of sufferers. In a new research project, scientists used genetically modified laboratory rats which overexpress large amounts of the alpha-synuclein protein. These rats have an increased propensity to accumulate harmful varieties of alpha-synuclein protein and to develop symptoms similar to those seen in Parkinson's patients. The researchers initiated the disease process by injecting alpha-synuclein into the small intestines of the rats.

"After two months, we saw that the alpha-synuclein had travelled to the brain via the peripheral nerves with involvement of precisely those structures known to be affected in connection with Parkinson's disease in humans. After four months, the magnitude of the pathology was even greater. It was actually pretty striking to see how quickly it happened."

Patients with Parkinson's disease often already have significant damage to their nervous system at the time of diagnosis, but it is actually possible to detect pathological alpha-synuclein in the gut up to twenty years before diagnosis. "With this new study, we've uncovered exactly how the disease is likely to spread from the intestines of people. We probably cannot develop effective medical treatments that halt the disease without knowing where it starts and how it spreads - so this is an important step in our research. Parkinson's is a complex disease that we're still trying to understand. However, with this study and a similar study that has recently arrived at the same result using mice, the suspicion that the disease begins in the gut of some patients has gained considerable support."


Senolytic Treatment Reverses Age-Related Loss of Regenerative Capacity in the Liver

You might recall a paper published last year in which the authors reported that cellular senescence is a primary cause of declining capacity in liver regeneration with age. Here the obvious next step is taken, and a senolytic therapy is tested for its ability to restore the capacity of the aging liver to regenerate by clearing senescent cells. Improvement in all sorts of measures that normally decline with age is the expected result of senolytic treatment at this point, given the extensive evidence accumulated to date. Senescent cells are a cause of aging and age-related decline, they actively maintain a dysfunction state of metabolism via their secretions, and thus of course getting rid of them helps. Though, as noted in this paper, things are never as simple as we might hope them to be.

Many tissues, including the liver, heart and limbs possess a limited regenerative capacity in newborn or young mice, but which is lost upon maturation. As far as we are aware, misregulation of senescence has not been causally linked to such loss of regenerative capacity. Here, we first assessed the dynamic patterns of senescence markers during liver regeneration in young and adult mice. Although a transient p53-independent increase in p21 is well described following partial hepatectomy, its precise functions remain unclear, and loss of p21 does not seem to adversely impact regeneration in young animals. However, in models of advanced aging and severe liver damage, aberrantly expressed senescence markers, including p21 and p16Ink4a have been reported to impede liver regeneration. For example, in models of liver fibrosis, a robust senescence response is induced primarily in the stellate cells, which serves to limit fibrosis. Other models of severe liver damage induce a pronounced p21-expressionin hepatocytes, which results in decreased regeneration, senescence,and senescence-spreading.

We find that following partial hepatectomy, the senescence markers p21, p16Ink4a, and p19Arf become dynamically expressed at an age when regenerative capacity decreases. In addition, we demonstrate that treatment with a senescence-inhibiting drug improves regenerative capacity, through targeting of aberrant p21 expression. Surprisingly, we also find that the senescence marker p16Ink4a is expressed in a different cell-population to p21, and is unaffected by senescence targeting. This work suggests that senescence may initially develop as a heterogeneous cellular response, and that treatment with senolytic drugs may aid in promoting organ regeneration.

Senolytic treatment is increasingly shown to have beneficial effects in enhancing tissue function and alleviating disease symptoms in a variety of tissues. However, in many cases, the specific cellular targets or molecular mediators in vivo remain to be identified. Our study suggests that p21-positive cells may be a primary target. This is supported by the findings that protection from apoptosis is a main function of p21, including in senescent cells, and many senolytics, including the one used here, work by blocking anti-apoptotic pathways. In addition,as p21 functions to protect cells from damage, prolonged loss of p21 in aging mice predisposes to cancer through loss of this cytoprotective effect.

Interestingly, our study suggests that a one-time removal of p21 positive cells using a senolytic has a beneficial effect on regeneration, but probably without the long-term consequences of p21-loss. Surprisingly however, we see no effect of senolytic treatment on the increased expression of p16Ink4a that is present prior to hepatectomy, and which becomes detectable at the same stage as the decrease in regenerative capacity. Many studies show how targeting p16Ink4a expression has beneficial effects on aged and damaged tissue. However, in most cases, this also results in reduction of p21 and p19Arf, making it difficult to discern specific effects of each gene.

As p16Ink4a and p21 are expressed in different cell populations in our study, this hints that p16Ink4a, at this level of expression at least, may have beneficial effects in the liver also. However, why senolytic treatment seems to eliminate p16Ink4a positive cells in other contexts and not here remains unknown, but probably relates to the level of p16Ink4a-expression or co-expression with other senescence genes, as p16Ink4a levels become increasingly higher with age. Perhaps with advanced age or chronic damage, p21 and p16Ink4a become co-expressed, and at higher levels in the same cell types, resulting in a full-senescence response, and what we witness here is an early stage in a cumulative and progressive decline that becomes more complex over time.


Short Term versus Long Term Gains in Working Memory Following Exercise

Research has established that exercise rapidly produces an improvement in memory function, within a matter of minutes. It is also the case that regular exercise slows cognitive decline with age and taking up exercise improves cognitive function in older individuals, when considered over the long term rather than immediately following exercise. Given that only a minority of the population in wealthier parts of the world, and particularly the older segment of the population, exercise to the degree recommended to best maintain health, these findings should probably be considered more a case of people doing themselves harm than a case of there being benefits to be obtained.

Today's research materials are interesting for directly comparing the short term and long term benefits of exercise to the operation of working memory in older people. The effect size is about the same, in that the same degree of improvement is observed immediately following exercise versus after a period of regular exercise, but the former benefit is very short-lived, while the latter benefit is sustained over time. The short-term benefit is also only observed in some people, and those differences correlated with structural differences in the brain. Is this all of any practical use at the present time, beyond being yet another recommendation to undertake more exercise? Probably not, but in the long term there is no such thing as useless knowledge.

New study suggests exercise is good for the aging brain

Researchers have found that a single bout of exercise improves cognitive functions and working memory in some older people. In experiments that included physical activity, brain scans, and working memory tests, the researchers also found that participants experienced the same cognitive benefits and improved memory, for a short time, from a single exercise session as they did in a sustained fashion from longer, regular exercise.

Previous research has shown exercise can confer a mental boost. But the benefits vary: One person may improve cognitively and have improved memory, while another person may show little to no gain. Limited research has been done on how a single bout of physical activity may affect cognition and working memory specifically in older populations, despite evidence that some brain functions slip as people age. Researchers wanted to tease out how a single session of exercise may affect older individuals. The team enrolled 34 adults between 60 and 80 years of age who were healthy but not regularly active. Each participant rode a stationary bike on two separate occasions - with light and then more strenuous resistance when pedaling - for 20 minutes. Before and after each exercise session, each participant underwent a brain scan and completed a memory test.

After a single exercise session, the researchers found in some individuals increased connectivity between the medial temporal lobe (which surrounds the brain's memory center, the hippocampus) and the parietal cortex and prefrontal cortex, two regions involved in cognition and memory. Those same individuals also performed better on the memory tests. Other individuals showed little to no gain. The boost in cognition and memory from a single exercise session lasted only a short while for those who showed gains, the researchers found.

The participants also engaged in regular exercise, pedaling on a stationary bike for 50 minutes three times a week for three months. One group engaged in moderate-intensity pedaling, while another group had a mostly lighter workout in which the bike pedals moved for them. Most individuals in the moderate and lighter-intensity groups showed mental benefits, judging by the brain scans and working memory tests given at the beginning and at the end of the three-month exercise period. But the brain gains were no greater than the improvements from when they had exercised a single time.

Acute Exercise Effects Predict Training Change in Cognition and Connectivity

Previous studies report memory and functional connectivity of memory systems improve acutely after a single aerobic exercise session or with training, suggesting the acute effects of aerobic exercise may reflect initial changes that adapt over time. In this trial, for the first time, we test the proof-of-concept of whether the acute and training effects of aerobic exercise on working memory and brain network connectivity are related in the same participants. Cognitively normal older participants (N=34) were enrolled in a randomized clinical trial. Participants completed fMRI resting state and a working memory task acutely after light and moderate intensity exercise and after a 12-week aerobic training intervention.

Functional connectivity did not change more after moderate compared with light intensity training. However, both training groups showed similar changes in cardiorespiratory fitness (maximal exercise oxygen uptake, VO2peak), limiting group-level comparisons. Acute effects of moderate intensity aerobic exercise on hippocampal-cortical connections in the default network predicted training enhancements in the same connections. Working memory also improved acutely, especially following moderate intensity, and greater acute improvements predicted greater working memory improvement with training. Exercise effects on functional connectivity of right lateralized fronto-parietal connections were related to both acute and training gains in working memory.

Repair of a Damaged Cornea Using Cells Derived from Induced Pluripotent Stem Cells

Since the discovery of induced pluripotency more than a decade ago, researchers have been working towards the use of this technology to produce cells for use in tissue engineering and regenerative therapies. Induced pluripotent stem cells are functionally equivalent to embryonic stem cells; given suitable recipes and methods for the surrounding environment and signals, they can be made to generate any of the cell types in the body. The cornea of the eye is a comparatively simple starting point for tissue engineering, easier to work with in many ways, in generating tissues and in delivering cells to the patient. Here, the first repair of a human cornea is reported, using tissue structures produced from induced pluripotent stem cells.

A Japanese woman in her forties has become the first person in the world to have her cornea repaired using reprogrammed stem cells. The woman has a disease in which the stem cells that repair the cornea, a transparent layer that covers and protects the eye, are lost. The condition makes vision blurry and can lead to blindness. To treat the woman, researchers created sheets of corneal cells from induced pluripotent stem (iPS) cells. These are made by reprogramming adult skin cells from a donor into an embryonic-like state from which they can transform into other cell types, such as corneal cells.

The woman's cornea remained clear and her vision had improved since the transplant a month ago. Currently people with damaged or diseased corneas are generally treated using tissue from donors who have died, but there is a long waiting list for such tissue in Japan. Japan has been ahead of the curve in approving the clinical use of iPS cells, which were discovered by stem-cell biologist Shinya Yamanaka. Japanese physicians have also used iPS cells to treat spinal cord injury, Parkinson's disease, and another eye disease. The Japanese health ministry gave permission to try the procedure on four people. The team is planning the next operation for later this year and hope to have the procedure in the clinic in five years.


LEAF Interviews David Sinclair

David Sinclair recently published a new book to assist in publicizing his present research directions, companies, and thinking on aging, and is here interviewed by the Life Extension Advocacy Foundation (LEAF) volunteers. The work presently underway includes supplements to increase levels of NAD+ in mitochondria and, separately, partial reprogramming of cells in a living individual in order to gain some of the effects of full reprogramming, particularly restoration of mitochondrial function. Fully reprogramming cells into induced pluripotent stem cells has been shown to clear out dysfunctional mitochondria and reset epigenetic markers of age to a more youthful configuration.

It is worth noting that this strategy will not be able to fix a great many of the issues that arise in cells with age, such as the accumulation of metabolic waste that even youthful cells cannot break down effectively. If it can be used to safely restore mitochondrial function in old tissues for an extended period of time, however, then that is certainly interesting enough to chase aggressively in and of itself. Mitochondrial dysfunction is a noteworthy aspect of aging, and is involved in numerous age-related diseases.

Currently, medicine treats the symptoms, not the causes, of age-related diseases. Do you think that we might soon reach the point where therapies will be taken in a preventive manner to delay the onset of age-related diseases?

Well, there's a subset of the population, particularly in the US, but increasingly around the world, who are using the internet to educate themselves and are trying to take action before they become sick. Sometimes with medical supervision, sometimes not. It's a grassroots movement right now; for it to become mainstream, the regulations would have to change so that doctors can feel comfortable prescribing medicines to prevent diseases. But, if we don't change, then we will continue to practice whack-a-mole medicine and only treat one disease at a time after it's already developed.

You are very well known for your work with NAD+ and its precursors; we're often asked whether nicotinamide riboside or nicotinamide mononucleotide is better?

They're very similar molecules, and both have been shown to provide a variety of health benefits in mice. That doesn't mean either of them will work to slow aging in humans, and that's why placebo-controlled clinical trials are required to know if one of them, or both of them, will work in certain conditions. Those studies began over a year ago, and they are currently Phase 1 safety studies in healthy volunteers. Next year, the plan is to test the pharmaceutical product in a disease area, most likely a rare disease, but also in the elderly to see if we can recapitulate some of the results we've seen in mice, such as increased blood flow and endurance.

Another area that you are involved in is partial cellular reprogramming to reverse age-related epigenetic alterations in cells and tissues. Please tell us a little bit about this approach and the approach that you are taking and how you're progressing so far?

For 20 years, we've been working on epigenetic changes as a cause of aging, starting with work in yeast and now in mammals. We've developed viral vectors and combinations of reprogramming factors that appear to be much safer than past approaches, and we've used them to reprogram the eye to restore vision in mice with glaucoma and in very old mice. Currently, it is believed that the epigenetic clock is just an indicator of age and not part of the actual aging process, but our recent work strongly suggests that the process of reversing the clock doesn't just change the apparent age of the body, it actually reverses aging itself by restoring the function of the old cells to behave as though they're young again. Therefore, the clock may not just be telling time; it may actually be controlling time.

Could you please tell us a little bit about your book and what the readers should look forward to?

"Lifespan: Why We Age and Why We Don't Have To" takes the reader on a journey through history, looking at the endeavor of humans to try to live longer and using that historical perspective to look at today's situation and project into the future. The book also takes readers on a journey through the very cutting edge of aging research and things that the reader can do right now to take advantage of these new discoveries in their daily lives with changes in their daily activity, what they eat, when they eat, but also medicines that are currently available on the market that may extend lifespan. The last chapter is about where we are headed, what are the medicines that are in development, and then when these drugs become available, what does the world look like? Is it a better place or a worse place, and how will our lives change?


Lower LDL Cholesterol and Blood Pressure Over a Lifetime Correlate with Greatly Reduced Risk of Cardiovascular Disease

Numerous genetic variants correlate with either lower LDL cholesterol or lower blood pressure. Some of these have been shown to result in greatly reduced risk of cardiovascular disease, such as variants in APOB, DSCAML1, ANGPTL4, and ASGR1. Researchers here adopt the position that one can use data on the health of individuals with these and other variants from a large population database as a way to model the outcome should a non-variant individual diligently control LDL cholesterol and blood pressure through lifestyle choices throughout life. This is probably a fair assumption, though it is also fair to suggest that not all of the relevant mechanisms touched on by these genetic variants are fully understood.

As one might expect, based on the results from earlier studies of specific variants and risk of cardiovascular disease, the data here shows a large reduction in risk for people who have one or more of these variants. This can then be associated with the level of reduction in LDL cholesterol and blood pressure needed for a non-variant individual to achieve the same outcome. Assuming, of course, that cholesterol levels and blood pressure are the only relevant mechanisms, or at least the dominant mechanisms. They are undoubtedly influential, given that higher LDL cholesterol accelerates atherosclerosis and higher blood pressure results in all sorts of tissue damage, but they are not the only influential processes in aging.

A life of low cholesterol and BP slashes heart and circulatory disease risk

In this study, researchers studied 438,952 participants in the UK Biobank, who had a total of 24,980 major coronary events - defined as the first occurrence of non-fatal heart attack, ischaemic stroke, or death due to coronary heart disease. They used an approach called Mendelian randomisation, which uses naturally occurring genetic differences to randomly divide the participants into groups, mimicking the effects of running a clinical trial.

People with genes associated with lower blood pressure, lower LDL cholesterol, and a combination of both were put into different groups, and compared against those without these genetic associations. Differences in blood LDL cholesterol and systolic blood pressure (the highest level that blood pressure reaches when the heart contracts), along with the number of cardiovascular events was compared between groups.

A long-term reduction of 1 mmol/L low-density lipoprotein (LDL), or 'bad' cholesterol, in the blood with a 10 mmHg reduction in blood pressure led to an 80 percent lower lifetime risk of developing heart and circulatory disease. This combination also reduced the risk of death from these conditions by 67 percent. The team found that even small reductions can provide health benefits. A decrease of 0.3 mmol/L LDL cholesterol in the blood and 3 mmHg lower blood pressure was associated with a 50 percent lower lifetime risk of heart and circulatory disease.

Association of Genetic Variants Related to Combined Exposure to Lower Low-Density Lipoproteins and Lower Systolic Blood Pressure With Lifetime Risk of Cardiovascular Disease

Numerous randomized trials have demonstrated that treatment for up to 5 years with therapies that reduce low-density lipoprotein cholesterol (LDL-C) and systolic blood pressure (SBP) reduce the risk of cardiovascular events. In addition, mendelian randomization studies suggest that the benefit of exposure to lower LDL-C levels and lower SBP may accumulate over time. Because the biological effects of LDL-C and SBP may be cumulative, long-term exposure to the combination of both could potentially substantially reduce the lifetime risk of cardiovascular disease. However, the association of combined lifetime exposure to both lower LDL-C and lower SBP with the risk of cardiovascular disease has not been reliably quantified.

Ideally, this question would be addressed by conducting a randomized trial to minimize the effect of confounding that can occur in observational studies. However, a randomized trial evaluating the association between maintaining prolonged exposure to both lower LDL-C levels and lower SBP with the risk of cardiovascular disease would take several decades to complete, and therefore is unlikely to ever be conducted.

In an attempt to fill this evidence gap, this study used genetic variants associated with lower LDL-C levels and SBP as instruments of randomization to divide participants into groups with lifelong exposure to lower LDL-C levels, lower SBP, or both; and then compared the differences in plasma LDL-C, SBP, and cardiovascular event rates in each group to estimate the association of combined lifetime exposure with the lifetime risk of cardiovascular disease in a manner analogous to a long-term randomized clinical trial. The primary objective of this study was to assess and quantify the association of prolonged exposure to the combination of both lower LDL-C and lower SBP with the lifetime risk of cardiovascular disease.