Leu H J, Feigl W, Susani M
Virchows Arch A Pathol Anat Histopathol. 1987;411(1):5-14. doi: 10.1007/BF00734508.
In organizing thrombi angiogenesis is not dependent on invasion of vasa vasora from the vascular wall. Mononuclear cells of the monohistiocytic system are always present within the clotted blood and are capable of differentiation into various types of mesenchymal cells, including endothelial cells. At first autolytic slits and clefts appear in the fibrinous superficial areas of the thrombus. They are gradually lined by spindle-shaped "pre-endothelial" cells that already possess immunohistological properties of endothelial cells but still resemble primitive mesenchymal cells ultrastructurally. Later these cells gain connection with each other by pseudopodia, overlapping and interdigitation until the channels in the fibrinous matrix are covered by an uninterrupted layer of cells. These cells are now characterized ultrastructurally by the appearance of specific endothelial organelles (Weibel-Palade bodies). Circulation within these channels begins from the blood stream. In addition, angiogenesis by sprouting of vasa vasora from the vascular wall occurs in those areas of the thrombus in contact with the vessel wall. In blood vessels with on unimpaired intimal layer, angiogenesis by invasion of capillaries occurs at an earlier date than capillary formation by mononuclear cells.
在有组织的血栓形成过程中，血管生成并不依赖于来自血管壁的血管滋养管的侵入。单核吞噬细胞系统的单核细胞总是存在于凝血块中，并且能够分化为各种类型的间充质细胞，包括内皮细胞。起初，自溶裂隙出现在血栓的纤维蛋白浅表区域。它们逐渐被梭形的“前内皮”细胞所覆盖，这些细胞已经具有内皮细胞的免疫组织学特性，但在超微结构上仍类似于原始间充质细胞。后来，这些细胞通过伪足相互连接，重叠并相互交错，直到纤维蛋白基质中的通道被一层连续的细胞覆盖。现在，这些细胞在超微结构上的特征是出现了特定的内皮细胞器（魏-帕小体）。这些通道内的循环从血流开始。此外，在与血管壁接触的血栓区域，会发生血管壁的血管滋养管发芽形成血管的情况。在内膜层未受损的血管中，通过毛细血管侵入形成血管的过程比单核细胞形成毛细血管的过程更早发生。
