Small-size circulating microparticles in acute coronary syndromes: Relevance to fibrinolytic status, reparative markers and outcomes

Abstract Background Recent evidence suggests that circulating microparticles (MPs) contribute to inflammation, coagulation and vascular injury. Majority of MPs have usually not been included into prior analyses due their small size and limited resolution of conventional equipment. Our aim was to assess levels of MPs of different cellular origin sized below 0.5 μm polystyrene beads, denoted as small-size microparticles (sMP), their relation to markers of cardiovascular repair and their impact on prognosis in patients with acute coronary syndromes (ACS). Methods In a cross-sectional study, we initially compared levels of sMP between patients with ST-segment elevation myocardial infarction (STEMI, n = 50), non-STEMI ( n = 47), stable coronary artery disease (CAD, n = 40) and healthy individuals (HC, n = 40). In a separate study, the prognostic value of sMP was assessed in patients with non-STEMI ( n = 160). Annexin V-binding sMP (sAMP), platelet CD42b+ sMPs (sPMP), endothelial CD144+ sMP (sEMP) and monocyte CD14+ sMP (sMMP) were quantified using high resolution flow cytometry. Endothelial progenitor cells (EPCs) and monocyte expression of scavenger receptors was quantified by flow cytometry. Fibrinolytic factors were measured by ELISA. Results Counts of sAMP and sEMP were lower in STEMI after PCI ( p