Effect of green tea consumption on endothelial function and circulating endothelial progenitor cells in chronic smokers

Background The present study was designed to investigate the effect and relationship of endothelial function and endothelial progenitor cells (EPCs) by green tea consumption in chronic smokers. The numbers of circulating EPCs have an inverse correlation with chronic smoking and endothelial dysfunction. Green tea catechin improved endothelial dysfunction in chronic smokers. Method and Results In 20 young healthy smokers, endothelial functions, defined by flow-mediated endothelium dependent vasodilation (FMD) of the brachial artery via ultrasound as well as the number of EPCs isolated from peripheral blood, were determined at baseline and at 2 weeks after green tea consumption (8 g/day). Circulating EPCs were quantified by flow cytometry as CD45lowCD34+KDR2+ cells and by acyl-low-density lipoprotein and fluorescein isotiocyanate-lectin double positive cells after culture for 7 days. Clinical characteristics and laboratory findings were not significantly different between the baseline and at 2 weeks after green tea intake. EPC levels were inversely correlated with the number of cigarettes smoked. Circulating EPCs by flow cytometry (78.6 +/- 72.6 vs 156.1 +/- 135.8/ml, p < 0.001) and cultured EPCs (118.2 +/- 35.7 vs 169.31 +/- 58.3/10 field, p < 0.001) increased rapidly at 2 weeks after green tea consumption. FMD was significantly improved after 2 weeks (7.2 +/- 2.8 vs 9.3 +/- 2.4, p < 0.001). The FMD correlated with EPC counts (r=0.67, p=0.003) before treatment and after 2 weeks (r=0.60, p=0.013). Conclusions A short-term administration of green tea consumption induces a rapid improvement of EPC levels and FMD. Green tea consumption may be effective to prevent future cardiovascular events in chronic smokers.