Pathophysiological importance of nitric oxide in coronary heart disease / Patofiziološki značaj azot-monoksida u koronarnoj bolesti srca

Summary: Nitric oxide (NO) is pr oduced by many cells in the body; however, its production by vascular endothelium is particularly important in the r egulation of blood flow . Vascular actions of NO include the following: dir ect vasodilation, indirect vasodilation by inhibiting the vasoconstrictor influences, anti-thrombotic, anti-inflammatory and anti-proliferative effects. Due to its importance in vascular function, abnormal production of NO, occurring in different diseases can adversely affect blood flow and other vascular functions. It has been suggested that alterations in NO generation ar e a critical cause of injury in the ischemic heart. A biologic link between the endothelial damage and ather osclerotic coronary arterial disease has been pr esumably related to de creased arterial bioavailability of NO thr ough the increased leucocyte and platelet adhesions, vasoconstriction and smooth muscle cell pr oliferation. However, the precise me chanism of the impair ed NO generation is not known, and there is a considerable contr oversy regarding whether myo cardial ischemia r esults in incr eased or decr eased NO for mation. Asymmetric dimethylar ginine (ADMA) is a natural, com petitive inhibitor, and one of the primary factors controlling the nitric oxide production. ADMA was found to be elevated and closely cor related with the impair ed vasodilator function in conditions associated with the endothelial dysfunction, such as hypercholesterolemia, hypertension, insulin resistance and type 2 diabetes, and renal failure. But ADMA also seems to be involved in myocar dial ischemia, since its plasma levels predict future coronary events in patients with the elevated cardiovascular risk. It has been r ecently reported that the elevated plasma ADMA concentrations in the acute coronary events ar e an independent car diovascular risk factor.