Fukao H, Ueshima S, Tanaka N, Okada K, Matsuo O
Department of Physiology, Kinki University School of Medicine, Osaka, Japan.
Thromb Res Suppl. 1990;10:11-20. doi: 10.1016/0049-3848(90)90374-l.
The effect of fibrin stimulation on the fibrinolytic potential in cultured human umbilical vein endothelial cells (HUVEC) was investigated in the normal state and aged state. The amount of antigen of the two fibrinolytic factors, tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1), was determined using ELISA and the ABC method, respectively. When a fibrin clot was overlayered on the normal HUVEC, the secretion of t-PA or PAI-1 from the HUVEC was greatly changed. That is, PAI antigen was decreased 3-fold and t-PA antigen increased slightly in the conditioned medium. On the other hand, when the aged HUVEC were stimulated by a fibrin clot, PAI antigen was increased 3-fold and t-PA antigen did not change in the conditioned medium. When the level of fibrinolytic activity in the conditioned medium was expressed as the molar ratio of PAI and t-PA (PAI/t-PA), the value in the fibrin-stimulated normal HUVEC was markedly reduced (a 3.5-fold decrease) when compared with that of the non-stimulated normal HUVEC, reflecting a profibrinolytic state. On the other hand, the value in the fibrin-stimulated aged HUVEC was markedly increased (a 5-fold increase) when compared with that of the non-stimulated aged HUVEC, reflecting an antifibrinolytic state. Actinomycin D- or cycloheximide-treated HUVEC showed no response to the fibrin stimulation. We conclude that the level of HUVEC-mediated fibrinolytic activity was regulated mainly by the production and secretion of PAI from the HUVEC to protect against the generation of thrombi. In the aged HUVEC, the regulatory mechanism acts in an opposite manner and a thrombotic process may be induced.
研究了纤维蛋白刺激对正常状态和衰老状态下培养的人脐静脉内皮细胞（HUVEC）纤溶潜能的影响。分别采用ELISA法和ABC法测定了两种纤溶因子，即组织型纤溶酶原激活物（t-PA）和纤溶酶原激活物抑制剂1（PAI-1）的抗原量。当在正常HUVEC上覆盖纤维蛋白凝块时，HUVEC中t-PA或PAI-1的分泌发生了很大变化。也就是说，条件培养基中PAI抗原减少了3倍，t-PA抗原略有增加。另一方面，当衰老的HUVEC受到纤维蛋白凝块刺激时，条件培养基中PAI抗原增加了3倍，t-PA抗原没有变化。当将条件培养基中的纤溶活性水平表示为PAI与t-PA的摩尔比（PAI/t-PA）时，与未刺激的正常HUVEC相比，纤维蛋白刺激的正常HUVEC中的该值显著降低（降低了3.5倍），反映出纤溶状态。另一方面，与未刺激的衰老HUVEC相比，纤维蛋白刺激的衰老HUVEC中的该值显著增加（增加了5倍），反映出抗纤溶状态。用放线菌素D或环己酰亚胺处理的HUVEC对纤维蛋白刺激无反应。我们得出结论，HUVEC介导的纤溶活性水平主要受HUVEC中PAI的产生和分泌调节，以防止血栓形成。在衰老的HUVEC中，调节机制以相反的方式起作用，可能会诱导血栓形成过程。
