In Vitro Studies on Human Endothelial Cells, Seeded on Materials for the purpose of Artificial Blood Vessels

血管内皮细胞在体内与血液接触，正常状态下不形成血栓。植入人血管内皮细胞（HUVEC）的人造高分子材料有望产生抗血栓形成的表面。这种混合材料可作为长期植入的人造血管。然而，血管内皮细胞在细胞因子的刺激下，会转变为促凝状态。本研究考察了HUVEC与人工材料对纤溶相关蛋白的相容性，即组织型纤溶酶原激活物（tPA）和1型纤溶酶原抑制剂（PAI-1）。得到以下结果：1)观察到HUVEC在培养初期4天释放出较高的tPA。2)用荧光合成底物测定的tPA活性在HUVEC培养基中几乎检测不到，而在灭活PAI-1的HUVEC裂解物组分中检测到tPA活性。从HUVEC中释放出来的tPA可能在培养基中与PAI-1形成复合物。3) tPA与PAI-1在培养基中释放量的比值取决于细胞外基质（ECM），即ECM蛋白和人工材料的使用。

Vascular endothelial cells contact with blood in vivo form no thrombi in the normal state. Artificial polymer materials where human vascular endothelial cells (HUVEC) are seeded may be expected to lead to antithrombogenic surfaces. Such hybrid materials will be useful as artificial blood vessels for a long-term implantation. Vascular endothelial cells, however, stimulated with cytokines, are known to change to the procoagulant state.In this study, the compatibility of HUVEC with artificial materials was investigated on fibrinolysis-related proteins, i.e., tissue-type plasminogen activator (tPA) and plasminogen inhibitor type 1 (PAI-1). The following results were obtained ;1) HUVEC were observed to be released relatively high amount of tPA in the initial culture period for four days.2) The activity of tPA,measured with a fluorogenic synthetic substrate, was scarcely detected in the culture medium of HUVEC,while the activity of tPA was detected in the HUVEC lysate component in which PAI-1 was inactivated. Probably, tPA,released from HUVEC,should form complex with PAI-1 in the culture medium.3) The ratio of amount of tPA against that of PAI-1, released in the culture medium, was dependent on extracellular matrices (ECM), i.e., ECM proteins and artificial materials used.