Search the Community
Showing results for tags 'mimetics'.
Found 2 results
Dean Pomerleau posted a topic in CR Science & TheoryI posted about this a while back on the (now defunct) CR email list, but I thought it interesting enough to bring up here, especially since the forum enables the inclusion of a very nice graphic illustration (see below)... CR (and exercise) are thought to serve as stressors which actively upregulate endogenous repair and defensive mechanisms that improve health and longevity in insects and animals. But plants have also had billions of years to evolve similar endogenous mechanisms to protect themselves from environmental stresses like drought, famine, insects, diseases, etc. The idea of xenohormesis is that phytochemicals are the signalling mechanisms of these stress responses in plants, and they are healthy for us because we share many of the same biochemical pathways with plants. The way Dr. Greger puts it in this video, rather than endure the hardship (sic?!) of calorie restriction ourselves to upregulate our defenses, why not torture plants, then eat them to gain the benefits of CR via the CR memetics they produce in response to the stress. What I thought was most interesting in the video was this figure (click to enlarge): which shows how specific, well-known plant phytonutrients (Curcumin in turmeric/curry powder, Resveratrol in red wine and ECGC in green tea), influence the same pathways that are modulated by calorie restriction (i.e. "low energy" in the diagram), and therefore may serve as (partial) CR mimetics. For more discussion on the topic, see this thread from the old mailing list. --Dean
All, Here is an MIT Technology Review article on a new study just getting underway to study the potential anti-aging effects of the CR mimetic rapamycin in dogs. It is directed by CR-friendly aging researcher Matt Kaeberlein from the University of Washington. Here are a couple highlights from the very informative article: Over time cells are degraded by several factors, including damaged DNA, misfolded proteins, and excessive inflammation. This degeneration can’t be stopped altogether, but researchers have found a surprising number of ways to slow it down in yeast cells and other living things. The common thread seems to be calorie restriction. If you cut down the food supply enough, a series of biochemical changes switch the body into a kind of lower gear so it can hunker down for survival. Rapamycin and other drugs that appear to slow aging in animals work by triggering this same biochemical pathway. The idea, says Harvard Medical School researcher David Sinclair, is to trick the body into acting as if it’s running out of energy and putting more effort into long-term survival. <snip> [A]t high doses, rapamycin can raise blood sugar and thereby increase the risk of diabetes. It causes mouth lesions known as canker sores. Researchers originally worried that because it works as part of an immune-suppressive cocktail for organ transplants, it would raise the risk of infection. But then a study last year in Science Translational Medicine showed that a derivative of the drug seemed to enhance human immunity following a flu shot. <snip> Rapamycin, originally isolated from soil bacteria on Easter Island and named after the island’s native name, Rapa Nui, is one of five drugs that have extended the lives of mice in studies. But it probably will be a lot easier to achieve life extension in mice than in people. Still, he and a number of others in the field are optimistic about rapamycin because it extended mouse life spans between 9 percent and 14 percent, and it worked whether mice began getting the drug during middle age or very late in their short lives. Moreover, it prevented cardiovascular damage and memory loss. That suggests that it might lengthen the period in which people are healthy and functional rather than drawing out a period of decline. <snip> The study includes only larger dogs, since they age faster than small dogs for reasons that are not completely understood, says University of Washington biologist Matt Kaeberlein, who is heading the study. The researchers plan to eventually follow 32 dogs in an initial phase, after which they’ll examine the data. One quarter of the dogs will get a placebo, not because dogs are subject to the placebo effect but to prevent bias in the owners who will be reporting regularly on their dogs’ health. So far the owners have reported no notable side effects, Kaeberlein says. “The last thing we want to do,” he says, “is harm people’s pets.” The article says the dogs in the study are all at least 6 years old. Since the larger breeds they are using typically live 8-14 years, these dogs are late middle age / early elderly, and it will be several years before longevity results are available. The whole article is worth reading. --Dean