RESUMO
BACKGROUND: First-degree relatives of patients with premature coronary artery disease (CAD) develop endothelial dysfunction even in the case they are apparently healthy. In this study we wanted to clarify whether reduced blood levels of circulating endothelial progenitor cells (EPCs), an endogenous repair mechanism to replace dysfunctional endothelium, or elevated endothelial-derived microparticles (EMPs), an indicator and a mediator of increased endothelial cell damage/apoptosis, are an initial step in the pathogenesis of endothelial dysfunction in genetically predisposed subjects. MATERIALS AND METHODS: Fifty-six healthy young men (aged 23 to 31 years) from a fire brigade were enrolled, of which 20 subjects had a positive family history (FH) for premature CAD. Subjects with or without a positive FH did not differ with respect to age, body mass index, risk factors and C-reactive protein. Endothelial function was assessed by hyperaemia-mediated relaxation of the brachial artery, blood levels of EPCs (VEGFR2(+)CD34(+) cells) and number of EMPs (CD31(+(bright))/Annexin V(+) particles) were analysed by flow cytometry. RESULTS: Hyperaemia-mediated relaxation of the brachial artery was similar in both groups, and the blood levels of EPCs were comparable. However, the number of EMPs were significantly increased in subjects with a positive FH compared to those with a negative FH (neg. FH: 55.31 +/- 4.88 vs. pos. FH: 70.37 +/- 6.32 particles microL(-1 )platelet poor plasma; P < 0.05). Number of EMPs correlate inversely with the FMD response. CONCLUSIONS: These results suggest that increased plasma levels of EMPs may be an initial step in the development of endothelial dysfunction in genetically predisposed subjects.
