YIA 6 Effects of limb ischaemia-reperfusion and radial artery injury on endothelial function and circulating CD133+/CD34+/VEGFR2+ endothelial progenitor cells

Rationale Circulating endothelial progenitor cells (EPC) increase after cardiovascular (CV) events. Whether this results from ischaemia or endothelial injury is unknown. We investigated effects of limb ischaemia-reperfusion (IR) and endothelial injury (EI) on endothelial function and EPC. Methodology Healthy subjects (n=42, 18–35 yr) underwent either limb IR generated by cuff inflation, or EI, induced by wire rotation through a cannula. Endothelial function was assessed by flow mediated dilation (FMD) and circulating CD34+/CD133+/VEGFR2+ EPC were enumerated by flow cytometry at baseline, 10 min, 1 h, 6 h, 2 days and 7 days. FMD and cytometry were also performed in patients (n=23, 40–75 yr) after EI from radial sheath insertion for coronary angiography, at baseline, 2 days, 7 days, 1 month and 4 months. Results Endothelial dysfunction occurred immediately after IR (50% reduction from baseline at 10 min, p Conclusions IR and EI cause significant endothelial dysfunction, proportional to the insult. More severe EI reduces CD133+/VEGFR2+ cells, consistent with consumption during repair. In health, CD133+/CD34+ cells expand after arterial insult. No expansion occurs in patients with CV risk factors, possibly reflecting impaired EPC mobilisation.