Extending Your Life
Through Genetics
By Charlene Laino
Imagine taking a drug that offers the promise of allowing you to live to be 180 " without suffering such crippling disabilities as arthritis or fatigue. That may no longer be the stuff of science fiction, thanks to new studies in genetics. While the work has so far only be done in worms, there is every reason to think it may be applicable to humans.
"THE FIELD of aging research is exciting because we feel we,re starting to really get somewhere, said Cynthia Kenyon , a professor of biochemistry and biophysics at the University of California at San Francisco. "This is new and mind-blowing. "If what we,re finding in lower organisms hold true for humans, it is possible that we might know how to change the rate of aging in humans within 20 years, she said. Kenyon discussed her research on anti-aging at an American Medical Association media briefing Thursday. "If you look in nature, you find that every animal ages at a different rate " a mouse only lives two years, a canary lives 13 years and a bat can live 50 years, she said. "These animals differ because of their genes, so it follows that genes in animals control their rate of aging. And now her new studies show that the genes that control aging are the same genes that control hormones involved in food metabolism " "a most fundamental process, as she puts it In her new work, Kenyon has been focusing on a small worm called C. elegans, studying what makes the worm age. According to Kenyon, there are many similarities between the cells of worms and other animals. "Its cells have to grow and divide and make tissues, make nerve chemicals, make muscles, just like other organisms do, she said. "The genes that control all those processes end up being the same genes that control these processes in us.
Calculate your life expectancy
C. elegans has a life span of about two weeks. But Kenyon found than when the gene known as daf-2 is altered, the worm,s life spa doubles. "So we now know that the worm has its own kind of death gene, Kenyon said. "In C. elegans, this gene speeds up the aging process. When its activity is inhibited, the worms live much longer, and remain active and youthful for much longer than normal. Th protein in worms that regulates life span looks similar to the hormone in humans that binds to insulin and IGF-1, which control food utilization and metabolism, she said.
So what does this mean for us? In essence, it means that a simple drug that blocks the action of such hormones might retard aging. In the worm, her team went in and directly changed its genetic material " telling the receptor not to bind as well to the hormone " and thus extending life span. "In humans, we would want to develop drugs that mimic this, she said. "If this pans out, it is quite reasonable to think we can double life span " and improve the quality of life, working toward eliminating aging diseases. The next step, Kenyon said, is to try to duplicate the work in mice. "By about five years from now, we should know if mice are wired similarly, she said. "If so, it should probably hold true for humans too.