Green Tea Catechins Improve Human Forearm Endothelial Dysfunction and Have Antiatherosclerotic Effects in Smokers

Background: Because green tea reduces cardiovascular and cerebrovascular risk, the purpose of this study aimed to elucidate the effect of green tea catechins (GTC) on endothelial dysfunction in smokers. Methods and Results: The 30 healthy male smokers were divided into 3 groups and given green tea beverages containing 0 mg (control group), 80 mg (medium-dose group) or 580 mg (high-dose group) of GTC daily for 2 weeks. Endothelial-dependent and- independent vasodilatation was investigated by measuring the forearm blood flow (FBF) responses to acetylcholine and sodium nitroprusside using venous occlusion strain-gauge plethysmography. The FBF response to acetylcholine significantly increased at 2 h and 1 and 2 weeks after GTC intake in the high-dose group, but no increase was observed in the other groups. FBF responses to sodium nitroprusside did not alter in any group at any time point. A significant increase in plasma nitric oxide and a decrease in asymmetrical dimethylarginine, malondealdehyde and 4-hydroxynonenal, C-reactive protein, monocyte chemotactic protein-1, and soluble CD40 ligand levels were detected after chronic consumption of high-dose GTC. Conclusions: GTC have antiatherosclerotic effects on dysfunctional vessels in smokers through increasing the level of nitric oxide and reducing oxidative stress. (Circ J 2010; 74: 578 - 588)