Circulating CD31+ annexin V+ apoptotic microparticles correlate with coronary endothelial function in patients with coronary artery disease

Objective - Endothelial dysfunction predicts morbidity and mortality in patients at cardiovascular risk. Endothelial function may be decisively influenced by the degree of endothelial cell apoptosis. Methods and Results - To test this hypothesis in humans, endothelial-dependent vasodilatation was invasively assessed in 50 patients with coronary artery disease (CAD) by quantitative coronary angiography during intracoronary acetylcholine infusion. Flow cytometry was used to assess endothelial cell apoptosis by quantification of circulating CD31(+)/annexin V+ apoptotic microparticles in peripheral blood. Increased apoptotic microparticle counts positively correlated with impairment of coronary endothelial function. Multivariate analysis revealed that increased apoptotic microparticle counts predict severe endothelial dysfunction independent of classical risk factors, such as hypertension, hypercholesterolemia, smoking, diabetes, age, or sex. Conclusions - In patients with CAD, endothelial-dependent vasodilatation closely relies on the degree of endothelial cell apoptosis, which is readily measurable by circulating CD31(+)/annexin V+ apoptotic microparticles. These findings possibly provide new options for risk assessment and may have implications for future treatment strategies of CAD.