Microparticles in acute coronary syndrome.

BACKGROUND: Emerging evidence supports the role of cell-derived microparticles (MPs) in the pathophysiology of acute coronary syndrome (ACS).

OBJECTIVES: To explore the relationship between coronary and systemic MP levels, investigate the correlation between MPs, inflammatory markers and Troponin T in patients with ACS.

METHODS: Thirty seven patients with ACS scheduled for percutaneous coronary interventions (PCI) were studied. Eleven patients with stable angina (SA) were included as a control group. AnnexinV+MPs (AnV+MPs) and activated platelet-monocyte aggregates (PMA) from right atrium (RA) and culprit coronary artery (CO) distal to culprit lesion were measured using flow cytometry. High sensitivity C-reactive protein (CRP), Interleukin - 6 (IL-6), tumour necrosis factor - α (TNF-α), serum amyloid A (SAA) and Troponin T were assayed.

RESULTS: Total and cell specific AnV+MP expression were higher in the ACS group in both the CO and RA, with greater levels detected in the CO. Platelet activation showed positive correlation with Troponin-T and platelet MP in both CO and RA of the ACS group (r=0.4 for both; p=0.04 & p=0.03 respectively). Inflammatory markers levels did not differ between the ACS and SA patients.

CONCLUSIONS: Elevated coronary and systemic MP levels and positive correlation of platelet activation with Troponin-T and platelet MPs suggest a pathogenic role for MPs in ACS.