Extended Deadline

Several people emailed me recently for my reaction to media stories on a University of Pittsburgh study in which the short lifespans of mice with a severe form of progeria (accelerated aging) were extended by injections of stem-cell-like muscle cells from young mice. So I took a look at the study and some related research, and here are some things that jumped out at me.

First, it has never been clear how much progerias can tell us about normal aging. Further, it’s not even clear which life-shortening syndromes to anoint as forms progeria, which implies that they have something to do with aging—there are a myriad degenerative diseases that shorten life and cause forms of bodily decay reminiscent of aging’s toll, and it’s a judgment call, sometimes rashly made, to label one of them a form of accelerated aging. Besides, no one knows whether 10% or 90% of the zillion forms of deterioration caused by aging, or something in between, must be present in a purported form of progeria in order for it to tell us truly interesting things about aging. As a general rule, I tend to think that progerias that kill very early in life, as does the one investigated in the Pittsburgh study (it’s called XFE progeroid syndrome, by the way, and it kills mice with a few weeks of birth), are usually less like normal aging than ones that work slower. Thus, I didn’t find the Pittsburgh study all that interesting at first glance—it seemed to be about a possible treatment for a rare congenital disease, not a study on aging.
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When I recently speculated that taking vitamin pills may contribute to unhealthy choices because many people assume the pills shield them from the choices’ ill effects, I figured there was no way to support my hunch. But I was mistaken: A recent Taiwanese study demonstrated that taking multivitamins does indeed make people feel protected against health hazards and thus more likely to indulge in unhealthy choices.

Led by Wen-Bin Chiou at National Sun Yat-Sen University, the researchers gave daily placebos for a week to 82 adults (45 women, 37 men, average age 31). They told half of the group that they were taking multivitamins, and at the end of the week administered surveys on the subjects’ health-related inclinations. The results: Those who thought they were taking vitamins reported a 44% higher tendency to partake in risky activities (examples included casual sex, sunbathing, and binge drinking), and a 61% higher preference for all-you-can-eat buffets over healthy meals, compared with those who knew they were taking placebos. The “multivitamin” group also reported exercising 14% less. The researchers concluded that multivitamin takers may experience an “illusory invulnerability” contributing to all kinds of risky behaviors.
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If you follow aging science—and my guess is that you’re one of those mortal, aging types who do—you might want to take a look at the latest issue of Scientific American (the January 2012 issue), which has a cover story I wrote for the magazine about research on target of rapamycin (TOR) and its implications for aging and finding ways to slow it down. Accompanying the article is a blog I wrote about how politics and faulty perceptions are preventing the huge practical promise of aging research from being realized, and why we should change that ASAP. There’s also a slide show about the very different rates of aging (and longevity) across mammals, and a piece on the extraordinary longevity of naked mole-rats, an adaptation of part of my book’s chapter on aging across species.

If you’ve tuned into the resveratrol story over the past five years, you’ve probably heard that you’d need to take giant doses of the red-wine ingredient to do any good. That idea was based on mouse studies in 2006 that showed massive doses of the compound blocked bad effects of eating too much fat. A front-page New York Times story on the studies, memorably headlined “Yes, Red Wine Holds Answer. Check Dosage,” conveyed the conventional wisdom at the time that “a 150-lb person would need to drink 750 to 1,500 bottles of red wine a day to get such a dose.”

Recent placebo-controlled clinical trials with resveratrol, however, suggest that much smaller doses—maybe a tenth as much as suggested by the Times‘ story—can have significant cardiac benefits. These smaller doses are still too large to get from drinking wine—you’d need to take resveratrol pills to equal them. But evidence is plainly growing that a rethink is in order.
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The negative buzz about sirtuins recently grew louder when Science ran a lengthy news piece on Dec. 2 titled, “Aging Genes: The Sirtuin Story Unravels.” The article played up studies in lower organisms casting doubt on earlier high-profile reports that sirtuin enzmes play major roles in aging, which in turn challenged the idea that they mediate health benefits linked to resveratrol, the famed red-wine ingredient. The most glaring of the skeptical reports, a British-led study that appeared in September in Nature, contradicted earlier studies that showed amping up a sirtuin called Sir2 in roundworms and fruit flies extends their lifespans. In the Science article, Linda Partridge, one of the British researchers, was quoted as saying that her team’s study “‘is basically a boring little story that says if you do the experiments properly,’ you arrive at the correct results.” This is pretty strong acid, no?

Partridge, along with editors of Science, apparently see the sirtuin story as an overfilled balloon begging to be popped. Joining in the fun, Nature‘s editors recently ran a headline—”Don’t write off sirtuins”—implying that they’re now in danger of being placed in the same category as a deadbeat’s IOU. But thanks to all the gleeful popping, we’re faced with a strange situation: The studies in yeast, worms and flies have totally upstaged a large, growing body of encouraging findings on sirtuins and resveratrol in mammals, including several small but revealing human clinical studies that recently appeared with little or no media notice. This situation is a first as far as I know when it comes to coverage of an important biomedical topic.
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