The mediterranean lecture: wine and thrombosis--from epidemiology to physiology and back

The protective effect of moderate alcohol consumption on the risk of cardiovascular disease has been consistently shown in many epidemiological studies. Antiatherogenic alterations in plasma lipoproteins, particularly increase in high-density lipoprotein (HDL) cholesterol,are considered as the most plausible mechanism of the protective effect of alcohol consumption on coronary artery disease (CHD). Other potential mechanisms contributing to the cardio-protective effects of moderate alcohol consumption include anti-thrombotic down regulation of blood platelet function, as well as of the coagulation and fibrinolysis balance. Since the proposal of a "French paradox" in the early Nineties, the possibility that consuming alcohol in the form of wine might confer a protection against CHD above that expected from its alcohol content, has made the topic"wine and health" increasingly popular. Many epidemiological studies have explored such a possibility, by comparing specific alcoholic beverage types (wine,beer, liqueur) in respect to their relative capacity to reduce the risk of CHD. In parallel, experimental studies have been done, in which wine and wine-derived products have been tested for their capacity to interfere with molecular and cellular mechanisms relevant to the pathogenesis of CHD. Wine might indeed conceivably have other ethanol unrelated beneficial effects. The biological rationale for such a hypothesis has been linked to the enrichment in grape-derived, non-alcoholic components, that possibly make it peculiar in respect to other alcoholic beverages. In fact, while the mechanisms underlying the effects of alcohol on cardiovascular disease have been limited to lipid metabolism and the haemostatic system, those related to wine consumption have also been extended to specific anti-inflammatory, antioxidant and nitric oxide related vaso-relaxant properties of its polyphenolic constituents. The effect of wine consumption has been carefully investigated to account for potential confounding of several conditions (inappropriate use of abstainers as control population, correlation between wine or total alcohol consumption and markers of healthy lifestyle and socioeconomic factors, diet, etc.). Strong evidence indicates that moderate wine consumption rather than confounders reduces both fatal and non fatal CHD events. In spite of the fact that the healthy effect of moderate intake of wine is by now well accepted, important issues remain to be resolved about the relationship between wine, alcohol and alcoholic beverages, the (possibly different) optimal amount of alcohol intake in men and women, the individual or environmental modulation of the alcohol related effect and the pattern of drinking. Some of these issues have been recently addressed in a large meta-analysis, in which the relationship between wine or beer consumption and CHD risk was quantitatively evaluated. We shall summarize here the experimental and epidemiological studies with wine or wine-derived products aimed at finding biological explanations for the supposed superior cardio-protective effects of wine consumption and to discuss some open questions about wine and vascular disease as approached in epidemiological studies.