The aging process: major risk factor for disease and death.

Abstract

Aging is the accumulation of changes responsible for the sequential alterations that accompany advancing age and the associated progressive increases in the chance of disease and death. Average life expectancies at birth in the developed countries are now approaching plateau values as the aging changes associated with the environment and disease near irreducible levels. The inborn aging process is now the major risk factor for disease and death after around age 28 in the developed countries and limits average life expectancy at birth to approximately 85 years. Future significant increases in average life expectancy-a rough measure of the healthy, productive life-span, i.e., the functional life-span-in these countries will be achieved only by slowing the rate of production of aging changes by the aging process. Many theories have been advanced to account for the aging process. The free radical theory of aging is discussed briefly. The importance attached to increasing the functional life-span dictates that aging hypotheses be explored for practical means of achieving this goal while work continues toward a consensus on the cause(s) of the aging process. Efforts to further increase the functional life-span by conventional measures are now almost futile, whereas those directed toward slowing the aging process are just beginning. These new efforts show promise.

Yno1p/Aim14p, a NADPH-oxidase ortholog, controls extramitochondrial reactive oxygen species generation, apoptosis, and actin cable formation in yeast

“…This includes also nonmitochondrial sources, besides the long-studied mitochondrially generated ROS. These findings can be viewed as important additions to the classical "free radical theory of aging" (1) and theories developed thereafter (2,3).…”

Protective effect of carnosine on adriamycin-induced oxidative heart damage in rats

“…However, CAT and GSH-Px activity also increased. It has been reported that a rise in SOD activity, without a concomitant rise in the activity of CAT and/or GSH-Px might be detrimental (33), because SOD generates hydrogen peroxide as a metabolite, which is cytotoxic and has to be scavenged by CAT or GSH-Px. Thus, a simultaneous increase in CAT and/or GSH-Px activities is essential for an overall beneficial effect of an increase in SOD activity (29).…”

Age-related changes in the activity and expression of manganese superoxide dismutase, and mitochondrial oxidant generation in female and male rats

“…It is suggested that age-related decline in health conditions is the result of accumulated damage over time [1,2]. In the "Free Radical Theory of Aging" proposed by Harman in 1950s, it has been suggested that the cumulative effect of free radicals produced during aerobic metabolism ultimately causes aging and death of all living things through oxidative damage [3].…”