Enhancement by human umbilical vein endothelial cells of factor Xa- catalyzed activation of factor VII

摘要: In blood coagulation on endothelium, an unperturbed vascular endothelial cell surface apparently provides activity equivalent to the phospholipid needed for generation of factor Xa and thrombin in soluble systems. Phospholipid systems also markedly enhances ability activate VII; therefore we investigated influence monolayer human umbilical vein cells (HUVEC) upon VII activation. HUVEC were found augment Xa-catalyzed activation VII. This appeared result from binding trace amounts cells. Adding active site-inhibited reaction mixtures, but not X, abolished enhanced either anti-factor V antibodies or exogenous Va had no effect rates. Thus does function as a cofactor reaction. further experiments prothrombin was studied by varying order addition supernatants monolayers. Evidence obtained that HUVEC, unlike platelets, possess functional site is independent Va. Since only known Xa/Ca2+-induced VII, demonstration presence cultured supports hypothesis procoagulant available luminal endothelium vivo.