Morphological and Immunohystochemical Characteristics of Aspirated Thrombi in Patients with ST-Elevation Myocardial Infarction

Abstract

The aim of study was to evaluate the morphological and immunohystochemical characteristics of aspirated thrombi in patients with ST-elevation myocardial infarction undergoing precutaneous coronary intervention to find the possible platelet activation and inflammatory cell involvement in coronary thrombi. Materials and methods. Thrombi collected from 67 patients with ST-elevation myocardial infarction were studied. Macroscopic and immunohystochemical analyses were performed to reveal the cellular components of thrombi. The peroxidase - antiperoxidase immunohystochemical method was applied with monoclonal antibodies to CD4+, CD8+, CD15+, CD63+ and CD105+ using diaminobenzidine agent as a visualization agent to investigate the potential involvement of different cellular subpopulations. Results. The macroscopic examination revealed friable thrombi with apparent laminations (lines of Zahn). Microscopic analysis of thrombi revealed a loose meshwork of fibrin fibers with compact accumulation of activated platelets. The platelets were surrounded by neutrophilic granulocytes.The immunohystochemical analysis confirmed that cell aggregates are consisting of CD 63+ activated platelets and leucocytes. The granulocytes also tested positive for CD15 antigen. The immunohystochemical analysis revealed the presence of CD8+ cytotoxic T-lymphocytes and CD4+ helper T-lymphocytes. No expression of iNOS, CD105 and VEGF was found in the analyzed thrombi. Conclusions. The hystopathological evaluation of thrombi in patients with acute ST-elevation myocardial infarction revealed the presence of activated CD63+ platelets and CD15+ neutrophilic granulocytes. Activated platelets and neutrophils may play a role in thromboinflammatory activation course leading to destabilization of atherosclerotic plaque and development of acute thrombosis in patients with ST-elevation acute myocardial infarction.