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Evidence that antioxidants can slow mitochondrial aging, at least in a lower
order animal, particularly the nematode worm, has come from a recent report
published in the September 1, 2000 issue of the journal Science. The study,
by scientists at Emory University, describes how the normal lifespan of
the nematode worm was extended by approximately 50%. The feat was accomplished
by treating the animals with synthetic forms of superoxide dismutase and
catalase - enzymes that naturally help control oxidative stress. The researchers
were also able to restore a normal lifespan to mutant worms that had a mitochondrial
defect causing increased oxygen free radical production and rapid aging.
The results suggest that using artificial means to neutralize harmful oxidants
can slow aging - at least in these primitive organisms. These experiments
extend observations that antioxidant vitamins are effective for sopping
up mitochondrial oxygen free radicals and slowing mitochondrial aging.
Clearly, drugs designed to neutralize mitochondrial oxidative stress
might be better equipped for their mission if they could selectively focus
on mitochondria. Scientists have succeeded in designing such a drug in
animal models. Researchers at the University of Otago School of Medicine
in New Zealand published a report in the May 2000 issue of Free Radical
Biology and Medicine describing the creation of antioxidants that are
specifically targeted to mitochondria. The compounds are thiol (sulfur-containing)
reagents that have a special affinity for mitochondria. The same group
had earlier created a targeted antioxidant that accumulated in mitochondria
to a level that was 80-times that of the normal level of a natural mitochondrial
antioxidant, vitamin E. However, translating these findings into safe,
effective drugs for humans, of course, will likely take several years
or more.
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