Procoagulant Stimulus Processing by the Intrinsic Pathway of Blood Plasma Coagulation

摘要

Potentiation of the intrinsic pathway of human blood plasma coagulation in vitro by contact with a solidprocoagulant surface leads to bolus release of thrombin (FIIa) in concentration proportion to the intensity of activation asmeasured by procoagulant surface area or energy (water wettability). This rather remarkable finding is confirmed using twodifferent assays: one triggering coagulation substantially through the intrinsic pathway alone and the second triggeringcoagulation through the intrinsic pathway in the presence of exogenous FIIa spikes.Similarity of experimental outcomes of these assays strongly suggests that endogenous FIIa production through the intrinsicpathway is independent of the absolute amount of FIIa present in plasma. Furthermore, we corroborate previous workindicating that procoagulant surfaces remain activating after repeated use and are not poisoned or denatured in the process ofactivating plasma coagulation. It is concluded that the sharp control mechanism that gives rise to bolus-production of FIIa fromthe intrinsic pathway must occur between surface activation of FXII and the FII → FIIa step, is not related to inhibition byFIIa, and does not involve deactivation of procoagulant surfaces.