Alcoholic beverages are known to exert a protective effect on atherosclerotic disease. This study aimed to assess the in vivo and in vitro
effects of alcohol on matrix metalloproteinase (MMP) -2 and -9, known to determine atherosclerosis progression. Eighteen healthy volunteers,
regular drinkers (two standard alcohol servings/day, on average) at first examination (baseline) were asked to abstain from any alcoholic
beverage for one week (abstention), and then to assume two standard alcohol servings of beer daily for 1 week (re-exposure). Activity
of MMP-2 and -9, total antioxidant activity (AOA), glutathione (GSH) plasma levels were carried out at baseline, at the end of abstention,
and after 1 week of re-exposure. To validate the in vivo results, MMP-2 activity and expression, AOA, and GSH, were determined in human
smooth muscle cells treated for 96 h with increasing concentrations (12.5e100 mM) of ethanol. MMP-2, but not MMP-9 plasma activity
was higher at abstention than at baseline or re-exposure (P!.001 and P#.005, respectively). Changes in AOA and GSH throughout the
study were not significant. No correlation was found between MMPs and antioxidant activity. In vitro, ethanol at 25 mM reduced by around
10% MMP-2 activity (P5.003) in smooth muscle cells, whereas MMP-2 expression, AOA, and GSH were unaffected. Alcohol reduces
MMP-2 plasma activity in healthy humans and in isolated vascular smooth muscle cells. This in vitro reduction is unrelated to MMP-2
expression in vascular cells or to antioxidant levels changes.
