Immortality Isn’t Quite Here

A popular maxim holds that the secret to longevity will be handed down by some aged sage: a Zen master, perhaps, or the representative of an alien race. But in recent weeks it has been two humbler organisms--yeast and a tiny roundworm called the nematode--and the enzyme telomerase (tel-AHM-er-ase) that have given scientists tantalizing insights into the mechanisms of eternal youth.

In the 1960s, California biologist Leonard Hayflick showed that human cells can divide only a limited number of times before dying, and in the 1980s scientists discovered why: Telomerase acts like a biological stopwatch, counting how many times a cell has divided and then telling the cell to shut down.

But last month, two competing teams of scientists announced their discovery of a protein in telomerase that can cause the cell to start up and be “youthful” again. On the same day, another team of scientists found that a gene known to extend life span in nematodes is remarkably similar to a gene that helps regulate metabolism in humans. And three days later, MIT researchers announced their finding that a genetic mutation causing premature aging in yeast works similarly in humans.

Some of the scientists used words like Holy Grail to describe their discoveries, but in truth, clinical applications to humans are a long way off. The problem with using the newfound telomerase protein to breathe new life into human cells, for instance, is that the same process also causes cancer. And though genetic engineers are seeking to extend life in yeast and worms, there’s no assurance that what works for those creatures would work for us too.

So while scientists may now be able to see the promise of a fountain of youth, it’s likely to be some while before we can drink from it.