Researchers discover compounds that slow aging across species

by Wendy Y. Lawton

Marc Tatar, an associate professor in the Department of Ecology and Evolutionary Biology, this month published a major paper in Nature. His work marks a true milestone in aging research: discovery of the first compounds that slow aging across species.

Along with colleagues at Harvard Medical School and the University of Connecticut, Tatar tested resveratrol, an antioxidant found in red wine, along with fisetin, a close cousin in its plant-based family. Tatar and the team fed the compounds to yeast, worms and flies. Results showed that molecules, called sirtuins, slowed aging in all organisms.

Flies, for example, live an average of 43 days. But flies that ate resveratrol lived up to 51 days. Flies that ate fisetin lived as long as 53 days.

Why? Sirtuins mimic the life-extending effects of caloric restriction, a biochemical cascade known to slow aging in mammals. Scientists don't fully understand why caloric restriction prolongs life. Tatar said the best thinking is this: Living creatures are hard-wired to reproduce. But a severe low-calorie diet trips physiological sensors, sending a message throughout the body that conditions aren't ripe for reproduction. Cellular defense systems go up and aging slows, preserving the body for better, more reproduction-friendly times.

"In this case, a little stress is actually beneficial," Tatar explained. "It's evolution."

What was startling about the experiment is that sirtuins don't extend life when coupled with real caloric restriction. In fact, when flies on a low-calorie diet ate resveratrol and fisetin, they didn't live any longer than average flies. Another surprising discovery was the fact that flies feasting on sirtuins didn't have problems reproducing - a negative side effect of caloric restriction.

One practical application of the research is in prescription drug development. But Tatar said a "Ponce de Leon pill" won't be found in pharmacies any time soon. Because sirtuins dissipate quickly in the blood, Tatar predicted that it would take scientists at least five years to create compounds stable enough for use in drugs.

Consumers shouldn't expect a silver-bullet centenarian pill. "We'd probably see these compounds used in drugs that target a specific age-related disease, such as diabetes or heart failure," he said. "If those diseases are delayed, we'd live longer."