Enzyme May Be Key to a Longer Life

WASHINGTON —  As Americans feasted on plates of Thanksgiving turkey Thursday, U.S. scientists reported they have made progress in understanding how eating less leads to longer life.

Studies in rodents, yeast and other organisms have found that drastically cutting calories extends life span, and researchers are striving to find out how that happens. The hope is that drugs may mimic that effect in humans, without making them eat less.

In a report in today’s edition of the journal Science, researchers said studies with fruit flies, which have many genes similar to mammals, showed that an enzyme called Rpd3 histone deacetylase likely is a key to longevity.

“If you decrease the level of enzyme without eating less, you still get life span extension,” said Stewart Frankel, a Yale University research scientist and the study’s senior author.

In the study, flies with genetic mutations that resulted in lower levels of the enzyme lived from 33% to 50% longer than normal. With a low-calorie diet, life span was extended by 41%.

The enzyme may be an attractive drug target, said Frankel.

He said more research, which probably would take several years, is needed before scientists find a drug that can safely provide the same effect in people. The drug would have to be convenient and safe to take for many years, he said.

One drug, called phenylbutyrate, is thought to target the Rpd3 enzyme, Frankel said. A study published earlier this year showed that feeding that drug to fruit flies extended their lives.