飲酒の抗血栓作用

―特に血小板機能との関連―

抄録

The relationship between alcohol consumption and incident ischemic heart disease and stroke is characterized by a J- or U-shape. This denotes that light drinking has a preventive effect on cardiovascular diseases. Effects of alcohol drinking on lipid metabolism including an increase in HDL cholesterol concentration and a decrease in LDL cholesterol concentration are the main reasons for the anti-atherosclerotic action of alcohol. The antithrombotic effect of alcohol through the inhibition of platelet function is also involved in the lower incidence of ischemic arterial disease in drinkers. Capacitative Ca²⁺ entry, a main mechanism for platelet aggregation, is inhibited by ethanol. Ethanol also inhibits plasmalemmal phospholipase A₂ activity and consequent thromboxane A₂ production. French paradox is a phenomenon showing the merit of red wine consumption for the prevention of ischemic heart disease. In addition to ethanol, red wine contains anti-oxidative polyphenol compounds, represented by resveratrol, which has an antiplatelet action. Resveratrol also inhibits the capacitative Ca²⁺ entry in platelets. Furthermore, ethanol and resveratrol show a synergic inhibitory action on platelet aggregation, which may be caused by the reduction in the Ca²⁺ sensitivity of the contractile apparatus of platelets and the attenuation of COX-1 activity. Thus, the strength of the antithrombotic action is thought to differ depending on alcohol beverage. Decreases in concentrations of coagulation factors including fibrinogen are also involved in the alcohol-induced antithrombotic action. Alcohol drinking causes hemorrhagic diathesis as well as antithrombotic tendency.