Initiation and propagation of blood coagulation at artificial surfaces studied in a capillary flow reactor
Initiation and propagation of blood coagulation at artificial surfaces studied in a capillary flow reactor
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DOI：
10.1055/s-0037-1614981
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发表时间：
1998-02-01
影响因子：
6.7
通讯作者：
Lindhout, T
中科院分区：
文献类型：
--
作者：
Blezer, R;Willems, GM;Lindhout, T
我们利用新型流动反应器来研究人工表面离体血液凝固过程的启动和传播。流动反应器由连接到第二玻璃毛细管的第一玻璃或聚合物毛细管组成，所述第二玻璃毛细管的内壁涂覆有25摩尔%二油酰磷脂酰丝氨酸/75摩尔%二油酰磷脂酰胆碱（DOPS/DOPC）的磷脂双层。柠檬酸盐化的无血小板血浆和CaCl 2溶液通过注射泵输送，并在流动反应器入口前混合。测定流出血浆的因子XIa、因子IXa、因子Xa和凝血酶活性。通过裸玻璃毛细管灌注纯化血浆导致液相因子XIa的瞬时产生。与此相反，因子IXa生产缓慢增加，达到稳定的稳态水平。我们确定，表面结合因子XIa负责因子IXa的连续生产。只有当接触活化血浆随后通过DOPS/DOPC包被的毛细管灌注时，才观察到因子IXa诱导的因子Xa和凝血酶的产生，表明因子IXa触发物的传播需要促凝血剂、含磷脂酰丝氨酸的磷脂膜。肝素涂层聚氨酯毛细管的带负电荷的内表面，当用抗凝血浆灌注时，与玻璃毛细管一样产生大量因子XIa和因子IXa。未发现普通肝素和无抗凝活性肝素之间存在差异。因此，可以得出结论，流动血浆中的接触活化和因子IXa生成不受固定化抗凝活性肝素的抑制。因此，因子IXa依赖性凝血酶生成在下游位于磷脂膜是相似的，无论固定化肝素的具体抗凝活性。
We have made use of a novel flow reactor to study the initiation and propagation of the ex vivo blood coagulation processes at artificial surfaces. The flow reactor consisted of a primary glass or polymer capillary that is connected to a secondary glass capillary, which inner wall was coated with a phospholipid bilayer of 25 mol% dioleoylphosphatidylserine/75 mol% dioleoylphosphatidylcholine (DOPS/DOPC). Citrated platelet free plasma and a CaCl2 solution were delivered by syringe pumps and mixed just before the entrance of the flow reactor. The outflowing plasma was assayed for factor XIa, factor IXa, factor Xa and thrombin activity. Perfusion of recalcified plasma through a bare glass capillary resulted in a transient generation of fluid phase factor XIa. In contrast, factor IXa production increased slowly to attain a stable steady-state level. We established that surface-bound factor XIa was responsible for a continuous production of factor IXa. Factor IXa-induced generation of factor Xa and thrombin was only observed when contact activated plasma was subsequently perfused through a DOPS/DOPC-coated capillary, showing that propagation of the factor IXa trigger requires a procoagulant, phosphatidylserine-containing, phospholipid membrane. The negatively charged inner surface of a heparin-coated polyurethane capillary, generated like the glass capillary significant amounts of factor XIa and factor IXa when perfused with recalcified plasma. No differences were found between unfractionated heparin and heparin devoid of anticoagulant activity. Thus, it is concluded that contact activation and factor IXa generation in flowing plasma is not inhibited by immobilised anticoagulant active heparin. Consequently, factor IXa-dependent thrombin generation at a downstream located phospholipid membrane was similar, regardless the specific anticoagulant activity of immobilised heparin.