Oxidant stress: the role of nutrients in cell-lipoprotein interactions

Oxidant stress is increasingly becoming an important hypothesis to explain the genesis of several pathologies, including cancer, atherosclerosis and a lso ageing. Beside a few rare genetic defects, dietary factors are thought to play a key role in the regulation of the production of reactive oxygenat ed species. An imbalance between nutrients, and in particular those involve d in antioxidant status, could explain the onset of an enhanced production of free radicals. We will briefly review information concerning oxidation o f lipids and Lipoproteins which lead to atherothrombosis. We also present n ew findings supporting a role for blood platelets in generating oxidant spe cies. New data are also described concerning the role of oxygenated derivat ives of cholesterol, oxysterols, in cellular cholesterol efflux and NO prod uction. Also, new developments relating to the influence of direct effects of free radicals on cellular cholesterol homeostasis are presented. Finally , the in vitro effects of butyrate, a natural short-chain fatty acid produc ed by bacterial fermentation, in the protection against free radical-mediat ed cytotoxicity are discussed. These data provide information on the mechan isms of dietary antioxidants in preventing oxidant stress.