Abstract
Several epidemiologic studies suggest that moderate consumption of alcohol, particularly red wine, lowers mortality rates from coronary heart diseases. Aberrant expression of tissue factor (TF), a cellular receptor of coagulation factor VIIa, is thought to contribute to the pathogenesis of coronary heart diseases (CHD) and acute coronary events associated with atherosclerosis. Therefore we hypothesized earlier that consumption of red wine provides protection against CHD by suppressing the aberrant expression of TF in vascular cells, and showed two red wine phenolics, resveratrol and quercetin, suppressed TF induction in endothelial cells and mononuclear cells. However these studies revealed that relatively high concentrations of these compounds (10 to 100 μM), which were unlikely to be achieved in vivo after moderate consumption of red wine, were needed to suppress TF induction. The present study was undertaken to investigate whether other red wine phenolics potentiate the inhibitory effects of resveratrol or quercetin and evaluate the effect of various resveratrol analogs, which were shown to be 10 to 1000 times more effective than resveratrol in modulating other cellular effects, on TF induction in mononuclear cells. Mononuclear cells isolated from healthy human blood donors were treated with various wine phenolics alone or in a combination for 1 h and the cells were stimulated with LPS (10 ng/ml for 6 h) to induce TF expression. TF activity in cell lysates was measured as its ability to support factor VIIa catalyzed activation of factor X. Studies of treating mononuclear cells with varying concentrations of resveratrol and quercetin alone or in a combination revealed that their inhibitory effects were additive and not synergistic. Treatment of cells with a cocktail of red wine phenolics (in concentrations that present in red wine) completely suppressed LPS-induced TF activity. Exclusion resveratrol, epicatechin, catechin or rutin from the cocktail did not diminish the inhibitory effect. In contrast, exclusion of quercetin from the cocktail fully attenuated the inhibitory effect of the cocktail. Further experiments showed that quercetin (55 μM) alone fully suppressed TF induction. Among various resveratrol analogs tested, the cis-form methylated derivative of resveratrol (3,5,4′-trimethoxystilbene, TMS) was 10-times more effective than resveratrol in inhibiting TF induction. A 2 μM of TMS inhibited the induction of TF by more than 75%. None of the wine phenolics or resveratrol analogs had a significant effect on the cell viability. Overall these data suggest that quercetin is the principal inhibitor of TF induction among red wine phenolics and no synergism exists among various wine phenolics in inhibiting TF induction. Comparison of our data on the effect of resveratrol analogs on TF induction with previously published studies on other cellular functions suggests that resveratrol analogs exhibit varying potencies in modulating different cellular activities.
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