Heterogeneity in Agonist-induced Activation Responses and Thrombus Formation: Differences between Large and Small Platelets

摘要: Background: Heterogeneity between the platelets of a subject exist in response to collagen and thrombin, for instance in Ca 2+-dependent exposure of procoagulant phosphatidylserine (PS). The reasons for these differences are largely unknown. Here, we investigated if platelet size is a contributor to this functional heterogeneity.Methods: Fractions of large and small platelets were separated by differential centrifugation, using blood from healthy blood donors. Aggregation of the isolated platelets was measured by light transmission aggregometry. In platelets loaded with fluorescent ratioed Ca 2+ dye, cytosolic Ca 2+ rises were measured in response to thapsigargin, 2-t-butylhydrochinone (TBHQ), or TRAP-6. Static adhesion of isolated platelets was followed in time by microscopy. Autologous blood, depleted from platelets and leukocytes, was reconstituted with large or small platelets at similar amounts or similar …