Isolated endothelial microparticles impaired ACh-induced vasorelaxation and nitric oxide production in a concentration-dependent manner, accompanied by increased superoxide production.
Do isolated endothelial microparticles impair endothelial function in vitro?
Endothelial microparticles directly impair endothelial function by reducing nitric oxide production and increasing superoxide production, suggesting they aggravate preexisting endothelial cell dysfunction.
Endothelial cell dysfunction (ECD) is emerging as the common denominator for diverse and highly prevalent cardiovascular diseases. Recently, an increased number of procoagulant circulating endothelial microparticles (EMPs) has been identified in patients with acute myocardial ischemia, preeclampsia, and diabetes, which suggests that these particles represent a surrogate marker of ECD. Our previous studies showed procoagulant potential of endothelial microparticles and mobilization of microparticles by PAI-1. The aim of this study was to test the effects of isolated EMPs on the vascular endothelium. EMPs impaired ACh-induced vasorelaxation and nitric oxide production by aortic rings obtained from Sprague-Dawley rats in a concentration-dependent manner. This effect was accompanied by increased superoxide production by aortic rings and cultured endothelial cells that were coincubated with EMPs and was inhibited by a SOD mimetic and blunted by an endothelial nitric oxide synthase inhibitor. Superoxide was also produced by isolated EMP. In addition, p22(phox) subunit of NADPH-oxidase was detected in EMP. Our data strongly suggest that circulating EMPs directly affect the endothelium and thus not only act as a marker for ECD but also aggravate preexisting ECD.
Brodsky et al. (Thu,) conducted a other in Endothelial cell dysfunction. Isolated endothelial microparticles (EMPs) was evaluated on ACh-induced vasorelaxation and nitric oxide production. Isolated endothelial microparticles impaired ACh-induced vasorelaxation and nitric oxide production in a concentration-dependent manner, accompanied by increased superoxide production.