APOPTOSIS AND AGING

During the adult life, a delicate balance between cell death and cell proliferation ensure that a constant number of cells is maintained throughout the organism. During the course of aging, this homeostatic control is altered and the equilibrium is shifted toward cell death. This results in considerable cell loss in senescent organisms. The true nature of this age-related cell deletion phenomenon could be apoptotic. Indeed, activation of the regulatory mechanisms of apoptosis may occur as a consequence of some pathophysiological alterations known to accompany aging. Namely, diminished synthesis of growth and/or survival factors, transmembrane signaling defects, defaults in the expression of particular genes implicated in cell cycle regulation, and the inability to cope with oxidative stress represent major risk factors liable to induce apoptosis. The untimely activation of biochemical pathways leading to apoptosis would result in excessive cell death, thereby contributing to the characteristic tissular and organismic atrophy observed during the process of senescence