Chemical Extends Cell Life Span

Researchers at an American Red Cross research laboratory in Bethesda, Md., have succeeded in greatly extending the life span of human cells grown in the laboratory, a feat that promises to shed new insight on the aging process.

Researchers have long known that human cells grown in a test tube can reproduce no more than 60 times before they die from old age--that somehow the cells are genetically programmed to die after that number of generations has been achieved.

But molecular biologist Thomas Maciag and his colleagues reported in Science last week that their life spans could be more than doubled, to as many as 140 generations, if the cells were given a chemical that blocks the activity of a gene that is the blueprint for a hormone called interleukin-1-alpha.

The group found that the cells continued to divide as long as they received the chemical every day, but died when it was withdrawn. The researchers are now trying to determine how the hormone, which also plays a crucial role in the immune system, causes death.