[Implications of oxidative stress in senescence]

After a short review of the literature concerning the paradox of oxygen and the participation of the oxidative stress created by the prevalence of its reactive radical species over the antioxidant enzymes, the main experimental arguments favoring the hypothesis of the implication of free radicals in senescence will be exposed. The amplification of degrading processes of lipid peroxidation and altering of the protein thiol groups in the presence of reactive oxygen species will be outlined. Both the aging of mitochondria due to the alteration of the electron transport chain and the oxidative attack on the mitochondrial DNA and the activation of the apoptosis as programmed cell death phenomenon in the presence of free radicals of oxygen, nitrogen and carbon will be given a particular interest. Finally, the implication of radical species in the production of some cardiovascular degenerative diseases of elderly patients will be discussed, together with the protective role of antioxidant compounds and diet, as factors that confine the progressive degradation of the senescent human body.