Reconstruction of cirrhotic liver by means of extracellular matrix remodeling and differential stimulation of stem cells.

本研究的目的是阐明骨髓来源的多能干细胞在肝细胞生长因子（HGF）cDNA基因治疗中对移植肝重建过程中的作用。[方法] C57 BL/6 J小鼠经口灌胃CCl_4（2.0ml/kg），持续6周，发展为肝硬化。经900 cGy照射后，这些动物接受了来自LacZ转基因小鼠的骨髓细胞移植。移植后，部分受者腹腔注射HVJ脂质体包裹的HGFcDNA（200μg/只），观察移植后肝细胞生长情况。每周一次，持续4周。对照动物接受空HVJ-脂质体。CCl_4持续给药，每周1次。在这些动物中，采用免疫化学方法研究了LacZ阳性骨髓源性细胞向肝脏中的募集。还检测了骨髓细胞表面c-Met/HGF受体的表达。[结果] HGF cDNA基因治疗能有效减轻小鼠肝硬化。在移植肝的重建过程中，供者来源的LacZ阳性细胞大多分化为内皮细胞或肝窦内皮细胞。小部分LacZ阳性细胞也分化为枯否细胞，但不分化为肝细胞、卵圆细胞和肝星状细胞。免疫组化法检测部分骨髓细胞c-Met表达。[结论]肝组织源性干细胞与骨髓源性干细胞联合诱导分化可有效地进行移植肝重建。HGF可能加速这些干细胞向肝构成细胞的分化。

The purpose of the present study was to clarify the role of bone marrow-derived multipotent stem cells in the reconstructing process of cirrhotic livers during gene therapy with hepatocyte growth factor(HGF) cCDNA. [Methods]C57BL/6J mice received CCl_4(2.0ml/kg p.o.) for 6 weeks, developing liver cirrhosis. After irradiation of 900cGy, these animals underwent transplantation with bone marrow cells derived from LacZ transgenic mice. After the transplantation, some of the recipients were injected with HGF cDNA encapsulated in HVJ-liposome(200μg/body i.m.) once a week for 4 weeks. Control animal received empty HVJ-liposome. CCl_4 administration was continued once a week during this period. In these animals, recruitment of LacZ-positive bone marrow-derived cells into the liver was investigated immunohistochemically. Expression of c-Met/HGF receptor on the cell surface of bone marrow cells was also examined. [Results]Gene therapy with HGF cDNA effectively attenuated liver cirrhosis in the mice. During the reconstructing process of the cirrhotic livers, most of the donor derived LacZ-positive cells differentiated into the endothelial cells or sinusoidal endothelial cells. Small part of the LacZ-positive cells also differentiated into Kupffer cells, but not into hepatocyte, oval cells, or hepatic sttelate cells. Expression of c-Met was detected immunohistochemically on some of the bone marrow cells. [Conclusion]These results suggest that reconstruction of cirrhotic liver is efficiently carried out in combination of hepatic tissue-derived and bone-marrow-derived stem cell differentiation. HGF possibly accelerates differentiation of these stem cells into liver-constituting cells.