Tiny creatures offer clues to human aging

When its aging gene is not working right, a worm named C. elegans lives three times longer than normal, according to Harvard researcher Gary Ruvkun. The development gene keeps an animal forever youthful in the sense that it never develops into a reproducing adult. There is a corresponding human gene, opening up fascinating possibilities. Worms that have lost the function of their daf-2 gene live for the human equivalent of 240 years. “We didn’t know how the worm gene actually regulates aging until we compared it with the human copy,” Ruvkun says. The human gene is responsible for making a protein receptor in cells. This receptor is activated by insulin, and the activation converts blood sugar into energy. In C. elegans, signals from its brain activate the worm equivalent of insulin, fueling the animal’s metabolism. When the gene doesn’t work, the worm burns less fuel and lives longer. “This is the first indication that aging may be regulated from the brain,” Ruvkun notes. “And it fits nicely with recent findings that insulin in rats, and possibly humans, may also act in the brain to control metabolism.”