Antioxidative defense mechanisms in the aging brain

Abstract

Aging is an extremely complex, multifactorial process that is characterized by a gradual and continuous loss of physiological functions and responses, particularly marked in the brain. A common hallmark in aging and age-related diseases is an increase in oxidative stress and the failure of antioxidant defense systems. Current knowledge indicates that the level of glutathione progressively declines during aging. Because nerve cells are the longest-living cells that exhibit a high consumption rate of oxygen throughout an individual's lifetime, the brain may be especially vulnerable to oxidative damage and this vulnerability increases during aging. In addition, the brain contains high concentrations of polyunsaturated fatty acids and transition metals and low antioxidative defense mechanisms. Although aging is an inevitable event, a growing volume of data confirms that antioxidant supplementation in combination with symptomatic drug treatments reduces oxidative stress and improves cognitive function in aging and age-related diseases. The present review discusses the neuroprotective effects of antioxidants in the aging brain.