Inhibition of human platelet aggregation by the proteolytic effect of streptokinase. Role of the human factor-VIII-related protein.
Defective ADP-induced aggregation was observed in in vitro streptokinases(SK)-treated normal platelet-rich plasma. Classic haemophilia and normal platelet poor plasma (PPP) treated with SK inhibit the aggregation of washed platelets; plasmin-treated normal human serum also shows an inhibitory effect on platelet aggregation. However, SK-treated von Willebrand plasmas do not inhibit the aggregation of washed platelets. This confirms the fact that the anti-aggregating effect is mainly linked to the digested factor VIII) but not to the digested fibrinogen. Defective ristocetin-induced platelet aggregation has also been observed in SK-treated plasmas. The presence of normal PPP does not modify the inhibition of the ADP-induced aggregation of washed platelets in SK-treated PPP. However, it does correct the ristocetin-induced aggregation. These results suggest that the inhibition of the ADP-induced aggregation is caused by the factor VIII degradation products, while the inhibition of the ristocetin-induced aggregation appears because of a defective von Willebrand activity of the factor VIII molecule.
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000941:Antigens / Q000032:analysis; D005169:Factor VIII / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D010447:Peptide Hydrolases / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects*; D012310:Ristocetin / Q000494:pharmacology; D013300:Streptokinase / Q000494:pharmacology*; D014842:von Willebrand Diseases / Q000097:blood
D000941:Antigens; D012310:Ristocetin; D000244:Adenosine Diphosphate; D005169:Factor VIII; D010447:Peptide Hydrolases; D013300:Streptokinase