There are many studies that involve extending the lives of laboratory animals – through gene manipulation, pharmaceutical intervention, and dietary restriction. But according to Steven Austad, a biologist at the Barshop Institute for Longevity and Aging Studies, these manipulations “pale in comparison to the remarkable diversity of lifespan produced by evolution.” He points out that maximum life span across the animal kingdom varies 40,000-fold. For example, some adult flies live less than an hour; some shellfish for centuries. Among mammals alone, longevity varies 1,000-fold.
The average fruit fly lives a little more than a month, so scientists’ ability to double its lifespan is a remarkable achievement but Austad says we may be missing something by focusing so much of our longevity research on animals—flies, worms, mice—that are “demonstrably unsuccessful at combating basic aging processes.” He suggests we put more effort into understanding molecular solutions nature has devised to help long-living creatures evade their deaths.
“Working on a dozen different species simultaneously is a new and unique approach to try to understand aging,” says Austad. “More and more animal genomes are being sequenced all the time, so we’re also getting more information.” And with that genetic information come greater opportunities to visually identify molecular differences between similar long- and short-lived species and examine whether long-living species have common traits that can be applied to humans.
“The answer to this phenomenon,” says Austad, “is in understanding the genome — the cell’s DNA.” They’ve discovered that the DNA of long-lived species repairs itself more quickly than that of short-lived species, and that their proteins are more stable and resistant to change. Healthy DNA helps organisms fight internal and external damage and disease, and keeps cells and organs functioning properly. Proteins, whose coding is contained within the DNA, form the cell’s structure and run the body’s chemical reactions. Stable proteins enable our cells and organs to operate longer, more efficiently. Both contribute to extended longevity.
Some laboratory animals in Dr. Austad’s research projects are evidence that life can be extended through science. His team has successfully increased the life span of test animals six-fold by manipulating genes associated with how the body processes insulin — a protein involved in metabolizing glucose. In another experiment, researchers found that mice that ate considerably less lived 30 to 40 percent longer, which, according to Austad, would be 20 to 30 years in human terms. Studies involving insulin activity and production hold tremendous promise for slowing aging as well as managing diabetes. In fact, Austad envisions a day when medicine will be able to encourage the body to mimic the chemical reactions that occur when food consumption is reduced. “Basically, you’ll flip a switch,” he says, “without having to eat less. You will take your little caloric restriction pill every day that will make you age more slowly.”
“Aging affects all of us,” says Dr. Austad. “People are going to continue to live longer because of medical advances. We want them to live healthier as well as live longer. The best way to achieve longer health is to figure out ways to medically slow aging. That’s a different sort of approach than figuring out how to cure cancer or heart disease. If you can cure aging, or if you can slow it, then you can really delay or prevent a whole host of disabilities and diseases.”