Anticoagulant synergism of heparin and activated protein C in vitro. Role of a novel anticoagulant mechanism of heparin, enhancement of inactivation of factor V by activated protein C.
Anticoagulant synergism of heparin and activated protein C in vitro. Role of a novel anticoagulant mechanism of heparin, enhancement of inactivation of factor V by activated protein C.
复制标题
肝素和活化蛋白C的体外抗凝协同作用。
DOI：
10.1172/jci119454
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Griffin,JH
中科院分区：
文献类型：
--
作者：
Petaja,J;Fernandez,JA;Gruber,A;Griffin,JH
研究了标准肝素与生理抗凝血浆蛋白--活化蛋白C（APC）的相互作用。肝素延长正常血浆活化部分凝血活酶时间和Xa因子-一期凝血时间的能力通过向测定中加入纯化的APC而显著增强。使用纯化的凝血因子的实验表明，肝素增强四倍的磷脂依赖性灭活因子V的APC。与因子V相反，肝素对APC灭活凝血酶激活的因子Va没有影响。基于SDS-PAGE分析，肝素增强APC对因子V而不是因子Va的蛋白水解速率。使用免疫耗竭血浆的凝血试验表明，APC对肝素作用的增强不依赖于抗凝血酶III、肝素辅因子II和蛋白S。使用纯化的蛋白质的实验表明，肝素不抑制凝血酶激活因子V。总之，肝素和APC在血浆中显示出显著的抗凝协同作用，这是由于三种机制同时降低了凝血酶原酶复合物的凝血酶生成。这些机制包括：第一，肝素增强凝血酶对因子V活化的抗凝血酶III依赖性抑制;第二，APC对膜结合FVa的失活;和第三，APC对膜结合因子V的蛋白水解失活，其被肝素增强。
Interactions between standard heparin and the physiological anticoagulant plasma protein, activated protein C (APC) were studied. The ability of heparin to prolong the activated partial thromboplastin time and the factor Xa- one-stage clotting time of normal plasma was markedly enhanced by addition of purified APC to the assays. Experiments using purified clotting factors showed that heparin enhanced by fourfold the phospholipid-dependent inactivation of factor V by APC. In contrast to factor V, there was no effect of heparin on inactivation of thrombin-activated factor Va by APC. Based on SDS-PAGE analysis, heparin enhanced the rate of proteolysis of factor V but not factor Va by APC. Coagulation assays using immunodepleted plasmas showed that the enhancement of heparin action by APC was independent of antithrombin III, heparin cofactor II, and protein S. Experiments using purified proteins showed that heparin did not inhibit factor V activation by thrombin. In summary, heparin and APC showed significant anticoagulant synergy in plasma due to three mechanisms that simultaneously decreased thrombin generation by the prothrombinase complex. These mechanisms include: first, heparin enhancement of antithrombin III-dependent inhibition of factor V activation by thrombin; second, the inactivation of membrane-bound FVa by APC; and third, the proteolytic inactivation of membrane-bound factor V by APC, which is enhanced by heparin.