Abstract 4331: Role of p-selectin Glycoprotein Legand in Occlusive Thrombus in Acute Coronary Syndrome: Immunohistochemical Analysis of Aspirated Tissue Samples
Introduction: Circulating inflammatory cells are considered to participate in formation of occlusive thrombus after plaque disruption in acute coronary syndrome (ACS). Recent studies suggested leukocyte-derived tissue factor (TF), a component of the extrinsic coagulation system, positive microparticles can bind activated platelets through the interaction of p-selectin glycoprotein legand-1 (PSGL-1). With immunohistochemical staining, tissues from thrombus aspiration therapy were analyzed.
Methods: Two hundred twenty consecutive samples were examined. Samples were stained with hematoxylin and eosin, elastica van Gieson, and phosphotungstic acid hematoxylin. The sample area, white thrombus area (platelets and fibrin), and red thrombus area (red blood cells and fibrin) were measured. As antibodies in immunohistochemical staining, CD66b expressed on activated neutrophils, CD68 on macrophages, p-selectin on activated platelets were employed respectively. In addition, immunohistochemical staining against TF, and PSGL-1 were performed.
Results: With digitalized area measurement for developing occlusive thrombus, red and white thrombi area ratio was correlated with whole sample area (r=0.48, p<0.01). Leukocytes were aggregated on the periphery of the white thrombus especially on the boundary between white and red thrombi. With immunohistochemical examination in this area, activation of neutrophils was observed with highly expression of CD66b. Among leukocytes in thrombus tissue, activated neutrophils were predominantly than macrophages. With abundance of the p-selectin positive activated platelets, PSGL-1 was highly expressed on aggregated leukocytes within ACS thrombi. In this area, percentage of PSGL-1 positive cells was related to the whole sample area (r=0.56, p<0.05). TF was also stained on immigrated leukocytes, and percentage of TF positive leukocytes was significantly correlated with the whole sample area (r=0.43, p<0.01).
Conclusion: These results suggested the circulating leukocytes and platelets might reciprocally participate in thrombus growth through the interaction of PSGL-1 positive leukocytes and p-selectin positive activated platelets in patients with ACS.