血管再生中的内皮祖细胞

循环血液里存在一种被称为内皮祖细胞(endothelial progenitor cells,EPCs)的祖细胞亚群,具有在体内外分化为成熟内皮细胞的能力。根据内皮祖细胞与其他血液细胞的粘附能力的差异和内皮祖细胞的抗原特异性,内皮祖细胞可通过贴壁培养和免疫磁珠筛选而分离获得。内皮祖细胞可特异性表达三种祖细胞分子标志：CD133、CD34和血管内皮生长因子受体-2。当内皮祖细胞分化为成熟内皮细胞后,血小板内皮细胞粘附分子-1(CD31)、血管内皮粘附素(VE-cadherin,又称CD144)和Ⅷ因子(vWF)表达将上调。越来越多的证据显示,内皮祖细胞有利于体内内皮损伤后修复和血管再生。我们的研究发现,内皮祖细胞可修复apoE-缺陷小鼠血管移植物中的损伤内皮并且在动脉血管外膜中存在大量的血管祖细胞。然而,在机体的血管再生和动脉硬化的形成进程中,这些内皮祖细胞的作用和机制还不太明确。另外,有关机体内相应心血管疾病危险因素是如何影响内皮祖细胞功能的机制也不清楚。因此,对内皮祖细胞的归巢、释放和粘附机制的进一步深入研究将有助于人们探索内皮祖细胞的基础理论和临床应用价值。

Endothelial progenitor cells in angiogenesis

Circulating blood contains a subtype of progenitor cells that have the capacity to differentiate into mature endothelial cells in vitro and in vivo. These cells have been termed endothelial progenitor cells (EPCs). The isolation of EPCs by adherence culture or magnetic microbeads has been described. EPCs are characterized by the expression of 3 markers, CD133, CD34, and the vascular endothelial growth factor receptor-2. After differentiation, EPCs express CD31, vascular endothelial cadherin, and von Willebrand factor. Evidence is accumulating that EPCs can facilitate endothelial repair and angiogenesis in vivo. We observed that EPCs can regenerate damaged endothelial cells in vascular grafts in apoE-deficient mice, and that abundant vascular progenitor cells are present in the adventitia of the vessel wall. It is not clear yet, however, whether these EPCs are essential for these angiogenic and atherogenic processes. Moreover, there are still many uncertainties about how cardiovascular risk factors alter EPC function. Thus, further studies on the mechanisms of EPC homing, releasing and attaching will be of help to explore areas of potential basic research and clinical application of EPCs.