Publicou 4 edições por ano
ISSN Imprimir: 2155-014X
ISSN On-line: 2155-0158
Endothelium-Independent Activation of Protein C in Whole Blood
RESUMO
Physiological conditions of formation and subsequent lysis of thrombi were reconstituted in the in vitro experiment. Thrombus formation in minimally altered whole blood was initiated either by adding exogenous thrombin or by the blood contact with anionic surface, which stimulates spontaneous (intrinsic) coagulation. Recombinant tissue plasminogen activator (rt-PA) and/or human protein C (hPC) were previously added to the blood sample. The time of the beginning and total degradation of blood clot as well as the level of total PC in clot's lysates was controlled. Addition of hPC alone or in combination with rt-PA led to the most effective lysis of blood clots: their residual weight was 18% and 5%, respectively, compared to the control clot formed without hPC and rt-PA. Addition of rt-PA alone or in combination with hPC caused a decrease in the total PC level during lysis of blood clots initiated either by contact way or by thrombin. Protein C level in lysate of blood clot formed by thrombin was 54% lower than that in spontaneously formed clot. Therefore, changes in the PC content in thrombus milieu seem to be controlled by thrombin at the stage of thrombus formation and by fibrinolytic system at the stage of fibrinolysis. The content of PC in lysate from a blood clot formed by exogenous thrombin was decreasing over the next 10 hours of clot lysis, which can also be the evidence of the interaction between the fibrinolytic and PC activation systems. It is postulated that the endothelium-independent pathway considerably influences plasma protein C activation in the presence of blood cells. Moreover, thrombolysis efficiently stimulates this pathway.