http://www.usnews.com/usnews/issue/...th/29kenyon.htm
Cover Story 12/29/03
In A Hurry To Slow Life's Clock
Cynthia Kenyon | Biologist
Outlook 2004: People to watch
By Nell Boyce
The first time Cynthia Kenyon laid eyes on an old worm, her life changed in a flash. Kenyon had been studying the genetics of tiny, translucent roundworms that produce hundreds of offspring. The older wrigglers always got lost in a sea of younger ones, but one day more than a decade ago Kenyon forgot to throw out a lab dish. This one held a mutant that made only a few offspring, so the oldsters stood out when she came across the dish a month later.
"There were all these old worms on the plate. I had never seen an old worm. I had never even thought about an old worm," Kenyon recalls. Shriveled and lethargic, the worms inspired her pity--and an idea. "I felt sorry for them. And I felt sorry for myself, `Oh, I'm getting old, too.' And right on the heels of that, I thought, `Oh, my gosh, you could study this.' " Kenyon has done that ever since, and she is finding increasingly strong hints that the aging clock can be slowed--in people as well as worms.
Her early work helped sweep away the notion that aging is an inevitable result of simple wear and tear. When Kenyon first got interested in aging, her colleagues tried to discourage her, saying the process is too complicated to understand, let alone control. But in 1993, her lab at the University of California-San Francisco doubled the life span of worms just by altering a single gene called daf-2, which makes a protein similar to the human insulin receptor.
"Few people were expecting single genes to have a huge effect," says David Sinclair, who studies aging at Harvard University. Thanks to discoveries like Kenyon's, "the field is exploding."
This October, for example, Kenyon's group described worms that live six times as long as normal, the equivalent of 500 human years. What's more, the super-old worms look and act young. When Kenyon first saw these old worms, she felt not pity but envy: "I wanted to be those worms."
That isn't a total fountain-of-youth fantasy anymore. Early this year, another lab reported that altering the daf-2 gene in mice increased life span by 26 percent, with no ill effects. If targeting this gene works in mice--much closer to humans than roundworms are--why not in people? Now Kenyon has set her sights on figuring out what normally controls daf-2 activity. Some early work, for example, suggests that environmental signals--for example, the smell of other animals, indicating overcrowding--might affect the gene and regulate life span.
A calling. Tracking the molecules that control our destiny has become Kenyon's calling. She was slow to find it. Although she is the daughter of a college professor, Kenyon dropped out of the University of Georgia, unsure what to do with her life. Then one day her mother brought home a book by DNA guru James Watson. Called the Molecular Biology of the Gene, it captured Kenyon's imagination and spurred her to study genetics: "It was like a path to understanding the secrets of the molecular underpinning of life."
For Kenyon, aging is the most tantalizing secret of all. Why, she wonders, do mice live only two years, while similar-size bats can live to 50? But she freely admits that pure curiosity isn't her only motivator. There's also the lure of a longer life.
Kenyon limits her intake of carbohydrates to keep her insulin levels low, since her work shows that animals with less active insulin receptors live longer. She has also helped set up a biotech company aimed at finding life-extending therapies that might work, for example, by regulating daf-2. "If our company could make a pill, every one would want it," says Kenyon. She says she's no exception: "I want to take that pill."
animals with less active insulin receptors live longer
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