The cumulative impact of oxidative stress on mitochondrial DNA

NEW YORK — The cumulative impact of oxidative stress on mitochondrial DNA may be responsible for many age-associated changes, perhaps including neurodegenerative disorders, Dr. M. Flint Beal said at the annual meeting of the Association for Research in Nervous and Mental Disease.

Some evidence suggests that increased antioxidant dietary intake or supplementation could ameliorate the process and attenuate the risk of Alzheimer’s disease, said Dr. Beal, professor and chairman of neurology at Cornell University, New York.

The “oxidative stress theory of aging” maintains that cells are subject to a constant imbalance between damage caused by reactive oxygen species and the protection afforded by endogenous antioxidant and repair mechanisms. As the theory goes, such damage increases with age, and the process is responsible for physiologic and functional deficits of aging.

Mitochondria would appear to be a prime candidate site of damage: 85%-90% of cellular oxygen consumption occurs in these structures, and 1%-3% of the process produces reactive oxygen species. “It’s the Achilles’ heel of the cell,” Dr. Beal said.


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