Oxidants, Antioxidants, and Aging

Abstract

INTRODUCTION: DEGENERATION AND AGING
Aging is associated with the degeneration of cells, tissues, and organs, resulting in diseases such as cancer, cardiovascular failure, cataracts, and Alzheimer’s disease, as well as the decline of most measures of physiological performance. Many scientists have focused on the molecular basis of age-associated degeneration, in the hope that its physiological complexity could be reduced to a limited number of principles. Implicit in this approach has often been the belief that aging results from random deleterious events (“stochastic” as opposed to “programmed” aging) (Finch 1990). Over the past four decades, a great deal of evidence has been gathered which validates this approach, and which suggests that oxidative damage is the major, although not the only, contributor to cellular degeneration; the resulting paradigm is often referred to as the “free radical theory of aging.” Although there are certainly aspects of aging that are not degenerative (Finch 1990; Medvedev 1990), we concern ourselves here with those theories that aim to explain cellular degeneration.

A number of recent reviews have addressed the role of oxidants and antioxidants in aging (Cutler 1991; Fleming et al. 1992; Floyd and Carney 1992; Harman 1992, 1993, 1994; Sohal and Orr 1992; Stadtman 1992; Ames et al. 1993; Feuers et al. 1993; Matsuo 1993; Nohl 1993; Sohal 1993; Shigenaga et al. 1994a; Warner 1994; Beal 1995; King and Barnett 1995; Knight 1995; Smith et al. 1995). In addition to updating these reviews, we aim to define the types of approaches that have been used...