ISOLATION OF ENDOTHELIAL PROGENITOR CELL FROM HUMAN UMBILICAL CORD BLOOD

内皮前体细胞（EPCs）在成人外周血中已被发现。我们研究了内皮祖细胞是否可以从脐带血（造血祖细胞的丰富来源）中分离，以及内皮祖细胞的体内移植是否可以调节出生后的新生血管形成。脐带血单个核细胞（MNCs）培养后可形成大量细胞簇、梭形和贴壁（AT）细胞以及索状结构。示踪实验显示，细胞簇、AT细胞和索状结构主要来源于CD 34阳性MNC（MNC <CD 34 +>）。更多数量的AT细胞和细胞簇从脐带血-MNCs比从等量的成人外周血-MNCs。AT细胞掺入乙酰化LDL，释放一氧化氮，并表达KDR，VE-钙粘蛋白，CD 31和血管性血友病因子，但不表达CD 45。局部移植的AT细胞在免疫缺陷裸鼠缺血组织中存活并参与毛细血管网络。因此，AT细胞具有多种内皮表型，并被定义为EPCs的主要群体。此外，激光多普勒和免疫组化分析显示，EPC移植定量增加缺血后肢的新血管形成和血流。总之，脐带血是分离内皮祖细胞的宝贵来源，脐带血来源的内皮祖细胞的移植将是一种新的策略，以调节出生后的新生血管。

Endothelial precursor cells (EPCs) have been identified in adult peripheral blood. We examined whether EPCs could be isolated from Umbilical cord blood, a rich source for hematopoietic progenitors, and whether in vivo transplantation of EPCs could modulate postnatal neovascularization. Numerous cell clusters, spindle-shaped and attaching (AT) cells, and cord-like structures developed from culture of cord blood mononuclear cells (MNCs). Fluorescence-trace experiments revealed that cell clusters, AT cells and cord-like structures predominantly derived from CD34-positive MNCs (MNC^<CD34+>). Greater numbers of AT cells and cell clusters developed from cord blood-MNCs than from an equal amount of adult peripheral blood-MNCs. AT cells incorporated acetylated-LDL, released nitric oxide, and expressed KDR, VE-cadherin, CD31, and von Willebrand factor but not CD45. Locally transplanted AT cells survived and participated in capillary networks in the ischemic tissues of immunodeficient nude rats in vivo. AT cells thus had multiple endothelial phenotypes and were defined as a major population of EPCs. Furthermore, laser Doppler and immunohistochemical analyses revealed that EPC transplantation quantitatively augmented neovascularization and blood flow in the ischemic hindlimb. In conclusion, umbilical cord blood is a precious source for isolating EPCs, and transplantation of cord blood-derived EPCs would be a novel strategy to modulate postnatal neovascularization.