Genetics of Aging & Longevity: The Search for the Fountain of Youth

PRODUCERS: Karen Michel

New & Noteworthy, 2007
by Jennifer Jongsma

Botox®, collagen and Restylane® injections, chemical peels, liposuction, implants … combating the appeara, collagen and Restylane® injections, chemical peels, liposuction, implants...combating the appearance of aging is big business. In The Genetics of Aging and Longevity: The Search for the Fountain of Youth, host John Hockenberry looked at our long history of fighting the effects of aging. In 221 bc, Emperor Qin Shi Huang, best known for building the Great Wall of China, searched for the "elixir of life." In 1513, Ponce de Leon traveled to what is now Florida in search of the Fountain of Youth. Today, researchers are still searching for the "fountain of youth," but they are turning to genetic tools, rather than foreign lands, to find it.

Calorie restriction has long been the only proven means to stave off all age-related diseases, including cancer, heart disease, osteoporosis, diabetes, and neurodegeneration. While it may be easy to severely limit the diets of research animals, it is not practical in humans. Therefore, many scientists are studying ways to mimic the effects of caloric restriction through other means. Sirtris Pharmaceuticals is just one of the many companies developing drugs that executives hope will extend human life-spans. One such drug is a formulation of resveratrol. Resveratrol is an antioxidant that significantly increases the lifespan of fruit flies, the worm C. elegans, and yeast. Researchers are hoping it does the same in humans.

Cynthia Kenyon, a biochemist at UC San Francisco, believes that calorie restriction works by activating "longevity" genes. Her experiments targeting a gene known as daf-2 have produced genetically mutant worms that live up to six times the standard lifespan. Daf-2 helps the organism resist free-radical damage and directs certain proteins to help fix damaged cells, two processes involved in aging. Many of these systems work in humans much like they work in worms, a promising finding for future anti-aging drug development.

In 2007, the Buck Institute, which is devoted solely to basic research on aging and age-associated disease, began a large-scale project to screen over 120,000 chemical compounds. Researchers are hoping to discover which ones affect lifespan in yeast, nematode worms, fruit flies, and mice. Gordon Lithgow, the project leader, said, "Our aim is to discover and develop novel compounds...opening up new avenues to treat, prevent or postpone age-related conditions such as Alzheimer's disease, cancer, arthritis, and diabetes, among others."

The fountain of youth still remains more myth than reality, but recent developments in anti-aging research offer some hope to those who want to "live forever." Of course, no one can cheat death, but living a long, healthy life without any of the diseases associated with aging might be as close as we can get.

Original Program Description, 2001

A New Yorker cartoon shows a nurse shouting into the ear of a very elderly man: "Scientists have extended the life of the fruit fly." True, and other experiments on worms and mice have yielded similarly tantalizing results.

But will these and other studies have any bearing on prolonging human life or postponing the debilitating diseases of aging?

In this program, you'll go on a tour of aging research that is part fantasy, part science - an appropriate style with which to present a field harboring so much promise and so much hype.

Producer Karen Michel is known for her creative use of the radio medium. She has crafted a program that is part NOVA and part Wizard of Oz. While touring Florida's Fountain of Youth, John Hockenberry meets the immortal Cleopatra, disguised as a tourist, who whisks him away to DeNial Lounge, a fantasy casino that scientists frequent. There he meets real scientists who are exploring which genetic mechanisms make us age, and are trying new ways to thwart or delay them.

One of the first scientists we meet is Cynthia Kenyon. She studies C. elegans, a tiny worm which has yielded some big surprises. She has found genes in this simple organism that indirectly regulate hormones connected to aging; further, these genes are also found in flies, yeast, and possibly humans. If she can figure out how to switch them off, she says, she may have found a key to slow the aging process.

We meet Stewart Olshansky and Bruce Carnes, biodemographers who say we will never extend the human lifespan much beyond what it is in developed countries today. Once we've cleaned up our public health and thwarted the big killers like infectious disease, they contend, we can't physically wring much more than 85 years out of our lot.

We'll also meet Roy Walford, who believes that the way to slow aging is through radically restricting diet. In one study he reduced the caloric intake of mice by 30 percent. These animals, which usually live to be 38 months old, lived for 54 months.

Walford has become so convinced of the approach he's practicing it on himself, living on just 1,500 calories a day.

And we meet Titia De Lange, who is looking for the mechanism that drives our biological clock. She studies telomeres, the tiny sequences of repetitive DNA at the end of our chromosomes. Each time a cell divides, another segment of the telomere falls off until the cell stops dividing or doing its work (most cells divide 60 times).

De Lange and other researchers' studies on telomeres may lead to clues about how the whole body ages.

What would the world look like with a large population of people, say, in their 100s? Would people live longer and healthier lives? Is aging a disease that modern medicine must cure?

Although none of the research discussed in this program has yet resulted in a bona fide cure for aging, it has provided new insight into what role aging must play in evolution.

Apparently, aging has been around since, well, the beginning of time.