In the past few years two ongoing studies of long term calorie restriction (CR) in primates have started to publish their results on longevity. Both research programs have been underway for more than 20 years, one run by the National Institute on Aging and the other by the University of Wisconsin-Madison. Researchers have followed small groups of rhesus monkeys to see how the benefits to health and life expectancy resulting from a restricted calorie intake compare with those obtained in mice and other short-lived species. At this point the results are ambiguous, unfortunately: one study shows a modest gain in life expectancy that has been debated, while the other shows no gain in life expectancy, and that result has also been debated.

Calorie restriction does produce considerable benefits in short term measures of health in rhesus monkeys and humans, that much is definitive, but the present consensus in the research community is that it doesn't greatly extend life in longer-lived primates - perhaps a few years at most in humans. Differences and issues in the two primate studies mean that effects of this size on longevity may never be clear from the data generated. Other factors will wash it out, such as differences in the diet fed to the control groups, or the different age at which calorie restriction started. Certainly the results so far support the conjecture that calorie restriction is exceedingly good for health but doesn't have the same impressive effects on longevity as it does in short-lived animals. Why that is the case is a puzzle to be solved - but not one that has a great deal of relevance to the future of human longevity. One would hope that we'll be a long way down the road to rejuvenation therapies by the time another set of better constructed primate studies are nearing completion.

You'll find a long article over at the SENS Research Foundation that examines the NIA and Wisconsin primate studies, their differences, and their results in great detail - but I'm just going to skip ahead and quote some of the conclusions:

CR in Nonhuman Primates: A Muddle for Monkeys, Men, and Mimetics

In this post, I have sketched out in detail two major possible interpretations of the disparate mortality outcomes in the NIA and WNPRC nonhuman primate CR studies. The "Diminishing Returns" hypothesis posits that the health and longevity benefits of "CR" reported in the WNPRC study were merely the unsurprising results of one group of animals being fed a high-sucrose, low-nutrient chow on a literally ad libitum basis, and another group being kept to portions of that diet low enough to avoid the deranged metabolisms flowing from obesity and (possibly) fructose toxicity. In this interpretation, the more severe restrictions of energy intake imposed at the NIA - particularly when the chow to which access was restricted may have been healthier to begin with - led to no further health benefit, because there are none to be gained: the dramatic age-retarding effects of CR observed in laboratory rodents and other species do not translate into longevous species such as primates, and the sole benefit of controlling energy intake is avoidance of overweight and obesity.

The "Dose-Response" hypothesis begins from the same interpretation of the WNPRC study, but posits that far from being excessive (or, at best, superfluous) to that required for good health, the additional energy restriction imposed at NIA were too little, and imposed during too narrow a window, to elicit a clear signal in health and lifespan benefits; this is supported by the evidence that the NIA primates were not especially hungry, and only weakly and inconsistently exhibited improvements in risk factors and endocrine signatures of CR that are seen both in life-extending CR in rodents, and in humans under rigorous CR.

Unfortunately, it seems very unlikely that this question will be resolved. Even the narrow question of whether the age-retarding effects of CR in laboratory rodents translate into nonhuman primates could only be established with confidence after yet another trial in nonhuman primates. [Such] a study is extremely unlikely in light of the enormous expense of the first two trials, disappointment (and possibly embarrassment) with the results, [and] the ill winds for nonhuman primate research. [Even] if such a well-designed and well-executed study were initiated: what then? Supposing that support were maintained for the duration of the experiment [it] would be a further three decades before the earliest point at which survival data could be reported.

The timescales involved in resolving these questions cannot be reconciled with the immediate imperatives that drive us to pose them. With the scale of the humanitarian, economic, and social crisis that looms in the coming decades due to global demographic aging and associated ill-health, the near-term need for effective interventions against the aging process could not be greater. Whether CR can retard aging in nonhuman primates or not; whether it can retard aging in humans or not; whether even effective CR mimetics can somehow be shepherded through clinical trials - even the most optimistic projection for retarding aging through such approaches is inadequate to the needs and suffering of aging world.

The point made in the article is the same one that should be made for all means of slowing the pace of aging by altering metabolism, whether by the use of drugs to replicate some of the changes caused by calorie restriction or via other mechanisms. These are very difficult and challenging projects, certainly very expensive in time and funds, and which will produce poor and uncertain end results even if successful. Ways to modestly slow aging do nothing for people who are already old, and we will grow old waiting for success in the development of drugs that can safely tinker our metabolisms into a state of slower aging.

The better approach is that outlined by the SENS Research Foundation: targeted therapies to repair the known forms of cellular and molecular damage that cause aging. This path is cheaper, more certain, and the resulting therapies will be capable of rejuvenation - of reversing degenerative aging, not just slowing it down a little. They will be greatly beneficial for the old, and extend the length of life lived in health and vigor. This is why I say that calorie restriction studies are irrelevant to the future of our health and longevity: the only thing that really matters is whether or not the SENS vision or similar repair therapies are prioritized, funded, and developed.

Source:
http://www.fightaging.org/archives/2013/05/reviewing-the-results-of-calorie-restriction-primate-studies.php

There are any number of techniques under development that allow individual cells to be destroyed provided that you can distinguish them from their neighbors: the challenge is in finding characteristic differences in the cells you want destroyed, such as cancer cells or senescent cells. Most of the efforts aimed at producing targeted cell destruction therapies are taking place in the cancer research community, but senescent cells accumulate with age and contribute to degenerative aging - they must also be destroyed. Unfortunately good ways to target senescent cells are somewhat lacking. Candidate mechanisms are emerging, however, and here is another of them:

Due to its role in aging and antitumor defense, cellular senescence has recently attracted increasing interest. However, [the] detection of senescent cells remains difficult due to the lack of specific biomarkers. ndeed, most determinants of cellular senescence, such as the upregulation of p53, p16Ink4a, p21WAF/CIP1 or SASP-associated cytokines, are not exclusively observed in senescence, but can also occur in other types of stress responses. In addition, alterations like SAHF or DNA-SCARS formation are frequently observed, but not necessarily a mandatory feature or exclusive to senescent cells.

The current gold standard for the detection of senescence is the so-called senescence-associated ?-galactosidase (SA-?-Gal) activity. Although SA-?-Gal has been first suggested as a distinct enzyme, its activity is derived from lysosomal ?-Gal encoded by the GLB1 gene. ?-Gal is an accepted marker of senescence, but its reliability and specificity have been questioned, as a positive ?-Gal reaction has also been detected in human cancer cells that were chemically induced to differentiate, or upon contact inhibition. Moreover, several cell types, such as epithelial cells and murine fibroblasts generally show a weak ?-Gal staining.

In the present study, we investigated several lysosomal hydrolases for their suitability as senescence markers and identified ?-fucosidase, a lysosomal glycosidase involved in the breakdown of glycoproteins, oligosaccharides and glycolipids, as a novel biomarker for senescence. We demonstrate that ?-fucosidase is upregulated [in] all canonical types of cellular senescence, including replicative, DNA damage- and oncogene-induced senescence. Our results suggest that detection of ?-fucosidase might be a highly valuable biomarker for senescence in general and in particular in those cases where SA-?-Gal activity fails to properly discriminate between senescent- and non-senescent cells.

Link: http://www.landesbioscience.com/journals/cc/article/24944/?show_full_text=true

Source:
http://www.fightaging.org/archives/2013/05/a-possible-biomarker-for-senescent-cells.php

Progress towards a therapy for the rare accelerated aging condition progeria continues. It remains unclear as to whether the mechanisms responsible for progeria exist in normal aging to a level that is in any way significant. Progeria is caused by malformed prelamin A, and tiny amounts of broken prelamin A can be found in old tissues - but it would really require a therapy for progeria that addressed the issues with prelamin A to easily find out whether this has any meaningful contribution to normal aging.

The classical form of progeria, called Hutchinson-Gilford Progeria Syndrome (HGPS), is caused by a spontaneous mutation, which means that it is not inherited from the parents. Children with HGPS usually die in their teenage years from myocardial infarction and stroke.

The progeria mutation occurs in the protein prelamin A and causes it to accumulate in an inappropriate form in the membrane surrounding the nucleus. The target enzyme, called ICMT, attaches a small chemical group to one end of prelamin A. Blocking ICMT, therefore, prevents the attachment of the chemical group to prelamin A and significantly reduced the ability of the mutant protein to induce progeria. "We are collaborating with a group in Singapore that has developed candidate ICMT inhibitor drugs and we will now test them on mice with progeria. Because the drugs have not yet been tested in humans, it will be a few years before we know whether these drugs will be appropriate for the treatment of progeria."

"The resemblance between progeria patients and normally-aged individuals is striking and it is tempting to speculate that progeria is a window into our normal aging process. The children develop osteoporosis, myocardial infarction, stroke, and muscle weakness. They display poor growth and lose their hair, but interestingly, they do not develop dementia or cancer." [The researchers are] also studying the impact of inhibiting ICMT on the normal aging process in mice.

Link: http://www.eurekalert.org/pub_releases/2013-05/uog-ptf051413.php

Source:
http://www.fightaging.org/archives/2013/05/inhibiting-icmt-as-a-progeria-therapy.php

We'll take a short excursion into ranking futurists for today, prompted by a recent article that offers a (transhumanism-slanted) opinion on the identity of the most important futurists of the past few decades.

The Most Significant Futurists of the Past 50 Years

Our visions of the future tend to be forged in the pages of science fiction. But for the past half-century, a number of prominent thinkers, activists, and scientists have made significant contributions to our understanding of what the future could look like. Here are 10 recent futurists you absolutely need to know about. Needless to say, there were dozens upon dozens of amazing futurists who could have been included in this article, so it wasn't easy to pare down this list. But given the width and breadth of futurist discourse, we decided to select thinkers whose contributions should be considered seminal and highly influential to their field of study.

Those selected include Robert Ettinger, one of the founders of modern cryonics, and Aubrey de Grey, who presently works to make his SENS roadmap to human rejuvenation a reality. Ray Kurzweil is notably absent from the list.

It isn't mentioned as a selection criteria in the article, but I think that ranking the importance of futurists by how effectively they help to create the future that they envisage isn't all that bad of an idea. Advocates and popularists play a needed role in moving from vision to reality, but progress also needs people to perform and orchestrate the actual work of research and development. Kurzweil, for example, is a popularist and an advocate with respect to his futurism: beyond the books and films and persuasion his day job as an inventor and entrepreneur is so far largely irrelevant to the future he envisages. I don't think anyone can argue that he isn't important in the arena of ideas regarding machine intelligence, accelerating change, and how this will all play out in the decades ahead. But how much more important would Kurzweil be if, for example, he had decided a decade or two back to create a company like Zyvex as a long term play to advance molecular manufacturing, or something equivalent in AI work?

In contrast Ettinger and de Grey both founded successful organizations devoted to realizing their particular visions: the Cryonics Institute and the SENS Research Foundation. Both were instrumental in creating the groundwork and the early community of supporters to enable a new industry and branch of research in applied medicine. That seems like the best approach to futurism to me: not just persuasion, but also working to create the change you want to see in the world.

Source:
http://www.fightaging.org/archives/2013/05/are-the-most-influential-futurists-those-who-put-in-the-work-to-make-their-visions-real.php

There are all sorts of good reasons to avoid becoming fat. Excess fat tissue is linked to an increased risk of all the common diseases of aging, and correlates well with a shorter life expectancy and higher lifetime medical expenditures. Fat tissue creates higher levels of chronic inflammation and alters the signaling environment in the body, causing a wide range of changes. Here is another of them:

Having too much body fat makes arteries become stiff after middle age, a new study has revealed. In young people, blood vessels appear to be able to compensate for the effects of obesity. But after middle age, this adaptability is lost, and arteries become progressively stiffer as body fat rises - potentially increasing the risk of dying from cardiovascular disease. The researchers suggest that the harmful effects of body fat may be related to the total number of years that a person is overweight in adulthood. Further research is needed to find out when the effects of obesity lead to irreversible damage to the heart and arteries, they said.

Researchers [scanned] 200 volunteers to measure the speed of blood flow in the aorta, the biggest artery in the body. Blood travels more quickly in stiff vessels than in healthy elastic vessels, so this allowed them to work out how stiff the walls of the aorta were using an MRI scanner. In young adults, those with more body fat had less stiff arteries. However, after the age of 50 increasing body fat was associated with stiffer arteries in both men and women. Body fat percentage, which can be estimated by passing a small electric current through the body, was more closely linked with artery stiffness than body mass index, which is based just on weight and height.

"We don't know for sure how body fat makes arteries stiffer, but we do know that certain metabolic products in the blood may progressively damage the elastic fibres in our blood vessels. Understanding these processes might help us to prevent the harmful effects of obesity."

Link: http://www.sciencedaily.com/releases/2013/05/130515085333.htm

Source:
http://www.fightaging.org/archives/2013/05/excess-body-fat-hardens-arteries.php