OBJECTIVETo investigate the correlation between the number and activity of circulating endothelial progenitor cells (EPCs), insulin resistance and severity of coronary lesions in patients with coronary artery disease (CAD).

METHODSPatients with coronary angiography evidenced CAD were divided in insulin resistance group (IR, n = 25) and insulin sensitive group (IS, n = 44) according to insulin level, 25 health volunteers served as control. Circulating EPCs were marked as KDR/CD133+ cells via fluorescence-activated cell sorter analysis. EPCs were also isolated from peripheral blood and cultured in vitro for 7 days, identified by DiI-acLDL uptake and lectin staining methods. EPCs migration activities were determined by modified Boyden chamber assay, EPCs proliferation activities were determined by MTT assay.

RESULTCirculating EPCs number was significantly lower in IR group compared with IS group [(0.34 +/- 0.08) per thousand vs. (0.47 +/- 0.09) per thousand, P < 0.01] and control group (P < 0.05). Both insulin resistance index (r = -0.291, P = 0.01)and Gensini score (r = -0.3984, P = 0.006)were negatively correlated with number of circulating EPCs. Proliferation and migration capacities of EPCs were also significantly lower in IR group compared to those in IS group (all P < 0.05) and control group (all P < 0.05).

CONCLUSIONSInsulin resistance/hyperinsulinemia could aggravate severity of coronary artery lesions via reducing the number and activities of circulating EPCs in patients with CAD.