Released platelet and granule contents: implication of thrombospondin in haemorrhagic diathesis in hepatosplenic schistosomiasis

ABSTRACT

This work was carried out on 75 subjects, 60 patients suffering from hepatosplenic schistosomiasis in different stages of the disease; in addition to 15 nonbilharzial normal controls. Thrombospondin and other platelet alpha granule contents including firbronectin, platelet factor 4, Beta-thromboglobulin, alpha 2-antiplasmin, plasminogen activator inhibitor, C1 inactivator, histidine rich glycoprotein, fibrinogen and plasminogen were studied. They were estimated in all groups in a trial to clarify the impact of thrombospondin and other alpha-granule contents on the alteration or haemostasis and haematemesis in hepatosplenic schistosomiasis. Specific investigations for platelets were estimated including bleeding time, platelet count and platelet aggregation. The data obtained revealed significant progressive decrease of the platelet alpha-granule contents studied [except thrombospondin] with the advancement of the disease especially in advanced fibrotic and haematemesis groups. Thrombospondin [TSP] showed significant progressive increase parallel to the progress of the disease. This may be explained by its longer life span and by its extraplatelet sources mainly the vascular endothelium. The data confirm that high level of TSP may serve as a templet whereupon the cofactors for the initiation or enhancement of fibrinolysis occur. These data confirm that the platelets play an important role in haemorrhagic diathesis in late stages of hepatosplenic schistosomiasis; this is through thrombocytopenia, decrease platelet function and its alpha-granule contents including antiproteases in addition to the important role played by TSP