[Oxygen radicals and cardiovascular diseases: pathogenetic mechanisms, therapeutic possibilities]

"Oxygen radicals" is a term used as a synonym for a group of reactive radical and non-radical species formed by successive univalent reduction of oxygen, interaction of the primarily formed oxygen radicals and by reaction of oxygen radicals with other molecules and ions of the biological system e.g. polyunsaturated fatty acids and halogenides. Besides physiological reactions (metabolism of xenobiotics and arachidonic acid; phagocytosis), the high reactivity of oxygen radicals leads also to unspecific reactions with biomolecules resulting in cell damage. In the last fifteen years, the participation of oxygen radical induced processes of damage (lipid peroxidation, thiol group oxidation, Schiff bases formation) in the pathogenesis of chronic and acute diseases of the heart and circulatory system was studied extensively. This review summarizes essential results of in vitro, animal and clinical studies including our own investigations on the biochemical basis between oxygen radical dependent cell damage and the relation between oxygen radical formation and the development of diseases in the heart and circulatory system (atherosclerosis, myocardial ischemia and reperfusion). Open questions concerning the causes of enhanced formation and diminished inactivation of oxygen radicals and pathogeneticly important targets of oxygen radicals in the heart and circulatory system are discussed.