May 12, 1999
Worm Enzyme May Help Extend Life
By JEFF DONN Associated Press Writer
Scientists have found an enzyme in worms that helps them live longer - a
discovery that raises hopes of finding treatments for Alzheimer's and
other human diseases associated with aging.
The next step is to determine whether a similar enzyme exists in humans.
The finding ``gets us closer to understanding what's involved in the
aging process and where we can intervene,'' said Anna McCormick, a
biochemist at the National Institute on Aging.
The research was led by biologist Martin Chalfie at Columbia University.
The findings were published in Thursday's issue of the journal Nature.
The researchers studied a nearly microscopic roundworm known as
Caenorhabditis elegans. When it is well-fed, it survives only about
three weeks, but it can withstand food shortages in a larval state for
at least two months. Several genes in this worm were already linked to
the larva's longer life, but their mechanism wasn't known.
The research team from Columbia and Dartmouth College identified an
enzyme known as a cytosolic catalase that seems to act as a central
agent in allowing some worms to live longer.
When the normal gene that makes the enzyme, ctl-1, is removed, the worms
die sooner.
The researchers argue that cytosolic catalase allows longer life by
performing a function it was already known to serve: blocking cell
damage caused by oxygen compounds.
Such oxidative damage - analogous to metal rusting - is already
implicated in human aging and diseases like Alzheimer's, Lou Gehrig's
and Parkinson's. Vitamin E, an antioxidant, is now used to prevent heart
attacks and treat Alzheimer's in some patients.
The discovery of the catalase gene bolsters the theory that oxidative
damage is central to both aging and its diseases.
The worm gene ``should give impetus to people working on the human genes
to try to look for things like this,'' Chalfie said. It may eventually
be possible to protect human nerve cells by boosting catalase with a
drug, McCormick suggested.
Siegfried Hakimi, a McGill University biologist who also studies life
span in roundworms, said researchers should now seek to establish if
higher levels of cytosolic catalase alone will make worms live longer,
not just block cell
damage.
Tom Johnson, a University of Colorado geneticist who also works with
roundworms, cautioned that their life-extending mechanisms may
ultimately have limited relevance to human disease.
But he said researchers have made roundworms live five times longer with
genetic manipulations. Johnson thinks such work suggests that people can
also live longer with the right drug - or mix of drugs - in the future.
``I'm not sure how much of a magic bullet it will be. I think it will be
a variety of bullets,'' he said.
Copyright © 1999 The Associated Press.
--
Judith Richards, London, Ontario, Canada
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