Zwaginga J J, de Boer H C, IJsseldijk M J, Kerkhof A, Muller-Berghaus G, Gruhlichhenn J, Sixma J J, de Groot P G
Department of Hematology, University Hospital Utrecht, The Netherlands.
Arteriosclerosis. 1990 May-Jun;10(3):437-48. doi: 10.1161/01.atv.10.3.437.
When the endothelial cell layer is damaged, a thrombotic reaction starts on the cells' subendothelium and on the connective tissue deposited by smooth muscle cells in the deeper layers. When more severe vascular damage occurs, hemostasis will involve the vessel adventitia in which fibroblasts are found. In this article, the influence of in vitro cultured endothelial cells, smooth muscle cells, and fibroblasts on the hemostatic balance was studied. To do so, perfusions were performed with low molecular weight heparin anticoagulated blood over the extracellular matrix of the cells. This method allowed the study of tissue factor-dependent thrombin generation and its influence on formation of fibrin and platelet aggregates. The experiments described in this article show that endothelial cells isolated from different human organs interfere differently in the hemostatic response. Endothelial cells isolated from umbilical veins are nonthrombogenic; they do not synthesize tissue factor under unstimulated conditions. On their extracellular matrix, only adherent platelets are found, but no aggregates and no fibrin. Endothelial cells isolated from omentum and atrium contain tissue factor activity under unstimulated conditions. As a consequence, thrombin is generated on their surfaces, and platelet aggregates and fibrin deposition are found on the extracellular matrices after perfusions with whole blood. The matrix of smooth muscle cells and fibroblasts behaved similarly. Increase in shear rate and perfusion time resulted in an increase in platelet aggregate formation. Polymerized fibrin deposition decreased when perfusions were performed at higher shear. Both platelet aggregation and fibrin deposition were tissue factor dependent and could be blocked more than 70% by an antibody against tissue factor. Based on these results, we conclude that endothelial cells isolated from umbilical veins form the best nonthrombogenic surface in vitro. Moreover, coagulation-dependent hemostasis should be included when thrombogenicity of subendothelium is discussed, especially when it concerns matrix derived from cells present in the deeper layer of the vessel wall.
当内皮细胞层受损时，血栓形成反应会在细胞的内皮下层以及更深层由平滑肌细胞沉积的结缔组织上启动。当发生更严重的血管损伤时，止血过程会涉及含有成纤维细胞的血管外膜。在本文中，研究了体外培养的内皮细胞、平滑肌细胞和成纤维细胞对止血平衡的影响。为此，用低分子量肝素抗凝的血液灌注细胞的细胞外基质。该方法能够研究组织因子依赖性凝血酶的生成及其对纤维蛋白和血小板聚集体形成的影响。本文所述实验表明，从不同人体器官分离的内皮细胞对止血反应的干扰方式不同。从脐静脉分离的内皮细胞不具有血栓形成性；在未受刺激的条件下，它们不合成组织因子。在其细胞外基质上，仅发现黏附的血小板，但没有聚集体和纤维蛋白。从大网膜和心房分离的内皮细胞在未受刺激的条件下含有组织因子活性。因此，在其表面会生成凝血酶，在用全血灌注后，在细胞外基质上会发现血小板聚集体和纤维蛋白沉积。平滑肌细胞和成纤维细胞的基质表现类似。剪切速率和灌注时间的增加导致血小板聚集体形成增加。在较高剪切力下进行灌注时，聚合纤维蛋白沉积减少。血小板聚集和纤维蛋白沉积均依赖于组织因子，并且可以被抗组织因子抗体阻断70%以上。基于这些结果，我们得出结论，从脐静脉分离的内皮细胞在体外形成了最佳的非血栓形成表面。此外，在讨论内皮下层的血栓形成性时，应考虑凝血依赖性止血，尤其是当涉及血管壁深层存在的细胞衍生的基质时。
