The Effect of Flow on Hemostasis and Thrombosis
The Effect of Flow on Hemostasis and Thrombosis
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DOI：
10.1055/s-0038-1646406
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发表时间：
1991-09
影响因子：
6.7
通讯作者：
Y. Nemerson;V. Turitto
中科院分区：
文献类型：
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作者：
Y. Nemerson;V. Turitto
虽然促凝剂的稀释通常被认为是流动减少表面凝结的机制，但这种机制从未经过实验验证，事实上，有理论依据怀疑这种假设的有效性 (29)。除了流动具有增强反应物和产物进出血管壁的运输这一明确的作用之外，流动还可能对血栓形成中涉及的某些酶或聚合动力学产生直接影响，这是非常合理的。流动对固定化酶的这种影响偶尔会被观察到，但从未在凝固过程中进行过研究 (30)。关于血流对止血和血栓形成的影响的研究虽然很多，但仍处于起步阶段。如上所述，增加剪切力会增加管式反应器中因子Xa的形成速率。在存在因子 VIII 和 IX 的情况下，剪切诱导的 Xa 生成也会增强 (31)。这些研究表明，在高剪切力存在下，至少一些凝固反应会加速。然而，据观察，随着剪切速率的增加，纤维蛋白的形成会减少 (20)。这意味着凝血级联的至少一个步骤被高剪切抑制。一种可能性是纤维蛋白单体被高局部流量条件去除，尽管纤维蛋白肽 A 的伴随减少与这种解释相悖。另一种尚未测试的可能性是凝血酶本身被血流去除。（摘要截断为 250 字）
While dilution of procoagulants has generally been proposed as the mechanism by which flow reduces coagulation at surfaces, such a mechanism has never been verified experimentally and, in fact, there are theoretical grounds for suspecting the validity of such a hypothesis (29). It is quite plausible that flow may have direct effects on certain enzyme or polymerization kinetics involved in thrombosis, in addition to the well-defined effect that flow has an enhancing transport of reactants and products to and from the vessel wall. Such effects of flow on immobilized enzymes have occasionally been observed, but never studied with respect to coagulative processes (30). The study of the effects of flow on hemostasis and thrombosis, while numerous, are still in their infancy. As noted above, increasing shear increases the rate of formation of factor Xa in a tubular reactor. In the presence of factors VIII and IX, there is also a shear-induced enhancement of Xa production (31). These studies indicate that at least some coagulation reactions are accelerated in the presence of high shear. However, it has been observed that fibrin formation is diminished at increasing shear rates (20). This implies that at least one step of the coagulation cascade is being inhibited by high shear. One possibility is that fibrin monomer is being removed by the high local flow conditions, although the concomitant reduction in fibrinopeptide A argues against this interpretation. Another possibility, not yet tested, is that thrombin itself is removed by flow.(ABSTRACT TRUNCATED AT 250 WORDS)