Nydahl S, Frebelius S, Swedenborg J
Department of Surgery, Karolinska Hospital, Stockholm, Sweden.
Thromb Haemost. 1993 Jan 11;69(1):41-4.
Disappearance of thrombin enzymatic activity was measured during recirculation through the microvasculature in a rat Langendorff heart preparation. This resulted in a 50% loss of thrombin from the recirculating solution. No increased loss of thrombin could be demonstrated if a mixture of antithrombin III and thrombin was recirculated, compared to thrombin alone. If, however, a heparin/thrombin mixture was recirculated, a 90% loss of thrombin could be demonstrated. Pretreating the microvasculature with large amounts of heparin resulted in recovery of antithrombin III in the recirculated heparin solution. At a subsequent recirculation with a heparin/thrombin mixture the loss of thrombin was decreased to the control level, as seen when recirculation with thrombin alone was performed. It is concluded that disappearance of thrombin enzymatic activity from a solution when recirculated through the microcirculation can be considerably increased if recirculated together with heparin, which probably reacts with endogenous antithrombin III on the vessel wall. The disappearance of thrombin in the absence of heparin was, however, unaffected by antithrombin III. The latter finding is compatible with the hypothesis that, in the microcirculation, antithrombin III/glycosaminoglycans play only a minor role for inhibition of thrombin coagulant activity and that thrombin binds mainly to thrombomodulin.
在大鼠Langendorff心脏制备模型中，通过微血管再循环过程中测定凝血酶酶活性的消失情况。这导致再循环溶液中凝血酶损失50%。与单独循环凝血酶相比，若抗凝血酶III和凝血酶的混合物进行再循环，未显示出凝血酶损失增加。然而，若肝素/凝血酶混合物进行再循环，则可显示出90%的凝血酶损失。用大量肝素预处理微血管，会使再循环的肝素溶液中抗凝血酶III恢复。在随后用肝素/凝血酶混合物进行再循环时，凝血酶的损失降至对照水平，这与单独循环凝血酶时的情况相同。得出结论：当溶液与肝素一起再循环通过微循环时，溶液中凝血酶酶活性的消失会显著增加，这可能是因为肝素与血管壁上的内源性抗凝血酶III发生反应。然而，在没有肝素的情况下，凝血酶的消失不受抗凝血酶III的影响。后一发现与以下假设相符：在微循环中，抗凝血酶III/糖胺聚糖对凝血酶凝血活性的抑制作用仅起次要作用，且凝血酶主要与血栓调节蛋白结合。
