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目的探讨循环早期内皮祖细胞(early-EPC)与外向生长内皮细胞(OEC)的生物学差别以及在血管新生中的作用。方法分离单个核细胞于体外培养early-EPC和OEC,并通过流式细胞仪测定CD14、CD34、CD45、CD105、CD133、血管内皮生长因子2型受体(VEGFR2)、血管性血友病因子(vWF)的表达情况。应用激光共聚焦鉴定细胞吞噬及结合的能力,并分别测定两种细胞的增殖能力、黏附功能、成血管能力以及分泌一氧化氮及血管内皮生长因子(VEGF)。其次,将18只日本大耳白兔随机分为early-EPC组(n=6)、OEC组(n=6)及对照组(n=6)。在3组动物制造出急性心肌缺血模型后,分别向心肌内移植early-EPC、OEC及培养液。4周后测定移植细胞的分布情况及血管密度,并分析心功能的变化。结果 early-EPC显示为CD14、CD45阳性,而OEC不表达CD14、CD45。两种细胞均表达内皮标志CD105、VEGFR2及vWF;均可以吞噬乙酰化低密度脂蛋白(ac-LDL)并结合荆豆凝集素1(UEA-1)。OEC增殖力、成血管能力较early-EPC明显增强,但两种细胞黏附能力及分泌VEGF、一氧化氮的能力无差别。early-EPC移植不能增加血管密度及改善心功能,而OEC可以整合入血管、促进血管新生并改善心功能。结论 early-EPC不具备祖细胞的特征。OEC具有祖细胞的特征,能促进缺血心肌的血管新生,是适合的移植种子细胞。
Objective To investigate the biological differences of early circulating endothelial progenitor cells (EPCs) and outward growth endothelial cells (OECs) and their roles in angiogenesis. Methods Mononuclear cells were cultured in vitro and early-EPC and OEC were cultured. The expressions of CD14, CD34, CD45, CD105, CD133, VEGFR2 and vWF were measured by flow cytometry vWF) expression. The ability of phagocytosis and binding of cells was identified by laser confocal laser scanning microscope. The proliferative ability, adhesion function, angiogenesis ability, and the secretion of nitric oxide and vascular endothelial growth factor (VEGF) were measured. Second, 18 Japanese white rabbits were randomly divided into early-EPC group (n = 6), OEC group (n = 6) and control group (n = 6). After 3 groups of animals were made acute myocardial ischemia model, respectively, early myocardial EPC transplants, OEC and culture medium. After 4 weeks, the distribution of transplanted cells and the density of blood vessels were measured, and the changes of cardiac function were analyzed. Results Early-EPC showed CD14 and CD45 positive, while OEC did not express CD14 and CD45. Both cells expressed endothelial markers CD105, VEGFR2, and vWF; both phagocytosed acetylated low-density lipoprotein (ac-LDL) and bound to Vitexin L-1 (UEA-1). OEC proliferation and angiogenesis were significantly enhanced compared with those of early-EPC, but there was no difference in the ability of both cells to adhere and secrete VEGF and nitric oxide. Early-EPC transplantation does not increase blood vessel density and improves cardiac function, whereas OEC integrates into blood vessels, promotes angiogenesis and improves cardiac function. Conclusion Early-EPC does not have the characteristics of progenitor cells. OEC has the characteristics of progenitor cells that promote angiogenesis in ischemic myocardium and is a suitable transplanted seed cell.