间充质干细胞免疫学特点及在肾脏疾病中的应用

Immunology characteristics and application of mesenchymal stem cells in treatment of nephropathy

间充质干细胞的多向分化潜能尤其是可分化为肾脏实质细胞的发现让肾脏移植提到了新的高度--自体肾脏移植。间充质干细胞仅低水平表达人类主要组织相容性Ⅰ类分子,而不表达人类主要组织相容性Ⅱ类分子,故而免疫原性较低。此外,间充质干细胞还可阻断树突状细胞的成熟,降低T细胞的免疫应答,并可通过分泌一些可溶性因子来介导免疫抑制。间充质干细胞上述独特的免疫调节功能使其在人和动物体内可以避免异种移植排斥反应的发生。已有较多报道利用啮齿类动物胚胎移植人的间充质干细胞异生培育出新的肾脏及输尿管,且可从成长后的输尿管收集的液体中检测到尿素氮和肌酐明显高于该动物的血清水平,这说明新的肾脏已经产生尿液,而且自体肾脏免疫原性小,植入后不良反应较少,来源供给方便,从而为自体肾脏移植的发展开辟了广阔空间。

Mesenchymal stem cells express major histocompability complex （MHC） Ⅰ in low levels, but do not express MHC Ⅱ, so it has a low immunogenicity. It can block maturity of dendritic cells, depress immune response of T lymphocytes, and also mediate immune suppression by secreting several soluble cytokines. In light of these characters, mesenchymal stem cell can avoid allograff rejection in human and animal transplantation. It has been reported previously that human mesenchymal stem cells cultivated in growing rodent embryos can grew out of new kidney and ureter. Furthermore, urea nitrogen and creatinine levels were significantly higher in liquid collected from the new ureter compared with the animal serum levels, which suggested that the new kidney had generated urine. This native kidney has low immunogenicity, little side-effect after transplantation, extensive sources, so it may have wide space in self-kidney transplantation.