Cardioprotection by regular ethanol consumption: potential mechanisms and clinical application

Abstract

Epidemiological studies demonstrate that excessive drinking is associated with hypertension, cerebral bleeding and loss of cardiac contractility. Conversely, studies have shown that mortality rates for people who regularly drink ethanol in moderation are lower than in abstainers, primarily due to decreased fatal ischemic heart disease. Further, moderate ethanol consumers have lower rates of myocardial infarction compared with abstainers. These beneficial cardiac effects may be due to pleiotropic effects of ethanol on lipids, platelets, and fibrinolytic activity. During the past decade, studies conducted in several animal models have revealed that light to moderate regular ethanol consumption renders hearts more tolerant to myocardial ischemia-reperfusion injury; to a degree similar to cardiac ischemic preconditioning (brief episodes of ischemia dramatically limit infarct size following prolonged ischemia). Recent clinical evidence suggests that light to moderate ethanol consumption in the year prior to myocardial infarction is associated with reduced mortality following myocardial infarction. These findings suggest that light to moderate ethanol consumption not only prevents myocardial infarction but also improves survival after myocardial infarction. Proposed mechanisms of cardioprotection by regular ethanol consumption include activation of adenosine A1 receptors, alpha(1)-adrenoceptors, protein kinase C-delta and epsilon, adenosine triphosphate-dependent potassium (K(ATP)) channels, nitric oxide synthase and reduced leukocyte-endothelial cell adhesive interactions. In this review, we focus on the recent progress in elucidating the endogenous myocyte signaling mediating cardioprotection by light to moderate ethanol consumption.