Moritoki Yuki, Ueno Yoshiyuki, Kanno Noriatsu, Yamagiwa Yoko, Fukushima Koji, Gershwin M Eric, Shimosegawa Tooru
Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai Miyagi, Japan.
Liver Int. 2006 May;26(4):457-66. doi: 10.1111/j.1478-3231.2006.01250.x.
Ductopenia is observed in end-stage human cholestatic diseases. The limited capability of cholangiocytes for proliferation is suggested to be the principal reason. Recently, bone marrow cells (BMCs) have been reported to behave as hepatic stem cells; however, their capability to differentiate into cholangiocytes in cholestasis remains unclear.
Normal mice were lethally irradiated to suppress the proliferation of self-BMCs; thereafter, the BMCs from enhanced green fluorescent protein (EGFP)-transgenic mice were transferred to recipients. Chronic cholestasis was induced by 0.1%alpha-naphtylisothiocyanate (ANIT) feeding. The proliferation of cholangiocytes and oval cells was assessed morphologically and immunohistchemically (cytokeratin-7 (CK-7), A6). Proliferative activity (proliferating cell nuclear antigen (PCNA) protein expression), hepatic growth factor (HGF) receptor (c-Met), stem cell factor receptor (c-kit), Notch2 and Hes1 expression were also evaluated.
Marked cholangiocyte proliferation was observed in ANIT-fed mice. However, no EGFP/CK-7 double positive cells were identified in any of the liver specimens after BMCs transfer (Tx). In hepatic parenchyma, there were scattered EGFP-positive cells, although none of them were positive for CK-7.
In spite of the significant ductular proliferations after ANIT feeding, no EGFP-positive cholangiocytes were confirmed by any other means in this chronic cholestasis model. Thus, different from hepatocytes, BMCs Tx seems not to contribute to the differentiation of cholangiocytes. Future studies are feasible to clarify the origin of proliferative cholangiocytes observed in this chronic cholestatic ductular hyperplasia model.
在人类终末期胆汁淤积性疾病中可观察到胆管减少。胆管细胞增殖能力有限被认为是主要原因。最近，有报道称骨髓细胞（BMCs）可作为肝干细胞；然而，它们在胆汁淤积时分化为胆管细胞的能力仍不清楚。
对正常小鼠进行致死性照射以抑制自身骨髓细胞的增殖；此后，将来自增强型绿色荧光蛋白（EGFP）转基因小鼠的骨髓细胞移植到受体小鼠体内。通过喂食0.1%的α-萘异硫氰酸酯（ANIT）诱导慢性胆汁淤积。通过形态学和免疫组织化学方法（细胞角蛋白-7（CK-7）、A6）评估胆管细胞和卵圆细胞的增殖情况。还评估了增殖活性（增殖细胞核抗原（PCNA）蛋白表达）、肝生长因子（HGF）受体（c-Met）、干细胞因子受体（c-kit）、Notch2和Hes1的表达。
在喂食ANIT的小鼠中观察到明显的胆管细胞增殖。然而，在骨髓细胞移植（Tx）后的任何肝脏标本中均未发现EGFP/CK-7双阳性细胞。在肝实质中，有散在的EGFP阳性细胞，但均未检测到CK-7阳性。
尽管在喂食ANIT后胆管有显著增殖，但在该慢性胆汁淤积模型中未通过其他任何方法证实有EGFP阳性胆管细胞。因此，与肝细胞不同，骨髓细胞移植似乎对胆管细胞的分化没有贡献。未来的研究有必要阐明在该慢性胆汁淤积性胆管增生模型中观察到的增殖性胆管细胞的来源。
