The Effect of Green Tea on Endothelial Function and the Circulating Endothelial Progenitor Cell in Chronic Smokers

ABSTRACT

BACKGROUND AND OBJECTIVES: Circulating endothelial progenitor cells (EPC) with an endothelial phenotype contribute to the regeneration and repair of arteries. The number of circulating EPCs has an inverse correlation with chronic smoking and endothelial dysfunction. Green tea cathechin many improve endothelial dysfunction. The effect of green tea cathechin on the number of circulating EPCs and the endothelial dysfunction in chronic smokers is not known. Subjects and METHODS: In 20 young healthy smokers (27.6+/-3.6 years, all male), the endothelial functions that were defined by flow-mediated endothelium dependent vasodilation (FMD) of the brachial artery, as well as the number of EPC isolated from peripheral blood, were determined at baseline and also at 2 weeks after taking green tea (8 g/day). The circulating EPCs were quantified by flow cytometry as CD45low CD34+ KDR2+ cells and as acyl-LDL and FITC-lectin double positive cells after culture for 7 days. RESULTS: The changes of the clinical characteristics and the laboratory findings were not different between baseline and at 2 weeks after green tea intake. The EPC levels were inversely correlated with the number of smoked cigarettes. Circulating EPCs, as determined-by flow cytometry, and the cultured EPCs increased rapidly at 2 weeks after green tea consumption (78.6+/-72.6/mL vs. 156.1+/-135.8/mL, respectively, p<0.001; 118.2+/-35.7/10 field vs. 169.31+/-58.3/10 field, respectively, p<0.001). The FMD was significantly improved after 2 weeks (7.2+/-2.8 vs. 9.3+/-2.4, respectively, p<0.001). The FMD was correlated with the EPC count before treatment (r=0.67, p=0.003) and after 2 weeks (r=0.60, p=0.013). CONCLUSION: The number of circulating EPCs and the FMD are reduced in chronic smokers. Green tea induces rapid improvements of the EPC levels and the FMD. A short-term of consumption of green tea may be effective for reducing the cardiovascular risk in chronic smokers.