Circulating microparticles: a marker of procoagulant state in normal pregnancy and pregnancy complicated by preeclampsia or intrauterine growth restriction

Summary In the present study, we explored the microparticles involved in the control of hemostatic equilibrium, i.e microparticles originating from platelet, endothelial cells and total MP defined as annexin V positive microparticles. Our aim was to analyze the level and procoagulant activity of these microparticles in normal pregnancy and pregnancies complicated with preeclampsia or isolated intrauterine growth restriction. We reported increased levels of platelet and endothelial microparticles in normal pregnancy compared to non pregnant healthy women. Number of annexin V microparticles was significantly increased together with their procoagulant activity. In pathological pregnancies, significant reduction in platelet microparticle number was found in preeclampsia. The procoagulant activity generated by the total annexin V MP was unchanged, suggesting that the microparticles remaining in the circulation were pro-coagulant. This study evidenced that microparticles constitute a cellular marker of a proinflammatory and procoagulant responses in normal pregnancy. In pregnancies with vascular complications, circulating MP with procoagulant potential may be part of the exacerbation of these responses.