人脐血基质细胞对脐血CD34^+细胞体外扩增的作用

Expansion of human umbilical cord blood CD34^+ cells using a co-cultured system with human umbilical cord blood stromal cell adherent layers

目的:研究人脐血基质细胞(hUCBSCs)对脐血CD34+细胞体外扩增的促进作用。方法:应用MACS磁珠分离系统分离脐血CD34+细胞,按照DEXTER法行脐血基质细胞培养,观察hUCBSCs的生长状态及细胞表面分子的表达情况。建立以hUCBSCs为滋养层的脐血CD34+细胞体外扩增体系,并对脐血CD34+细胞短期扩增后行集落形成单位(CFU)GM、CFUE和CFUMg半固体培养。结果:脐血基质细胞为混合细胞群,包括CD68(+)、Fn(+)、CD31(+)和CD34(-);以hUCBSCs为滋养层的体外扩增体系对脐血CD34+细胞具有明显的扩增作用,体外液体扩增后的脐血CD34+细胞集落形成能力明显高于对照组,其中细胞因子(SCF+IL3+EPO+TPO+GMCSF)联合hUCBSCs体系的扩增作用最强,hUCBSCs在促进CFUMg集落形成的作用中具有明显优势。结论:hUCBSCs具有体外支持造血作用,与细胞因子联合对促进脐血CD34+细胞扩增作用更加明显。hUCBSCs对促进巨核细胞扩增可能具有特殊的意义。

Objective:To elucidate the effects of human umbilical cord blood stromal cells(hUCBSCs) on expansion of umbilical cord blood CD34^(+) cells in vitro. Methods:Cord blood CD34^(+ )cells were separated by MACS system from 9 fresh samples. Cord blood stromal cells were cultured by using DEXTER culture system of stromal cells and their morphologic appearance and expression of surface antigen were examined. Human umbilical cord blood CD34^(+ )cells were expanded by coculture with hUCBSCs,or cytokines or both. The expanded CD34^(+ )cells were assessed for the degree of expansion and the number of colony-forming units in semisolid culture. Results:hUCBSCs were composed of several kinds of cells,and were positive for CD68,Fn and CD31,and negative for CD34. Adherent layer of hUCBSCs,alone or combined with cytokines,increased CD34^(+ )cells expansion. Ex vivo formation of CFU of expanded CD34^(+ )cells was significantly higher than that of primary CD34^(+ )cells. SCF+IL-3 +EPO+TPO+GM-CSF+hUCBSCs manifested the most potent combination. hUCBSCs had a significant superiority on the expansion of CFU-Mg. Conclusion:Human umbilical cord blood stromal cells could be used for the expansion of CD34^(+ )cells. Combining cytokines with hUCBSCs could further increase the degree of expansion. hUCBSCs could be of special value in enhancing expansion of CFU-Mg.