ROLE OF REACTIVE OXYGEN SPECIES IN CARDIOVASCULAR AGING

Biochemical and structural changes occurring in the myocardium with ag ing are mainly resulting from the association of a general tissue atro phy with the hypertrophy of the remaining myocytes. Whilst hypertrophy seems to be a compensatory process to the loss of cardiomyocytes and to a mild systolic hypertensive condition that accompanies elderly peo ple, atrophy should be the modification more closely related to aging 'per se.' In support to the free radical theory of aging, several sign s of oxidative damage have been shown in the aged heart, such as lipof uscin accumulation, decreased phospholipid unsaturation index, greater formation of both hydrogen peroxide and 8-hydroxy-2'deoxyguanosine. A s a compensatory reaction, the activities of the main oxygen-radical s cavenger enzymes are stimulated in the mitochondria of aged rat heart. Endothelium-mediated vasoregulation is more susceptible to oxidative stress in aged with respect to young rats, suggesting that also the va sculature can be negatively influenced by the oxygen free radicals gen erated during aging. The possible primary role of oxygen free radicals in the development of myocardial atrophy is also discussed.