Alison M R, Golding M, Sarraf C E
Histopathology Department, ICSM, London, UK.
Int J Exp Pathol. 1997 Dec;78(6):365-81. doi: 10.1046/j.1365-2613.1997.500375.x.
The ability of the liver to regenerate is widely acknowledged, and this is usually accomplished by the entry of normally proliferatively quiescent hepatocytes into the cell cycle. However, when hepatocyte regeneration is impaired, small bile ducts proliferate and invade into the adjacent hepatocyte parenchyma. In humans and experimental animals these ductal cells are referred to as oval cells, and their association with defective regeneration has led to the belief that they are the progeny of facultative stem cells. Oval cells are of great biological interest since they may represent a target population for hepatic carcinogens, and they may also be useful vehicles for ex vivo gene therapy for the correction of inborn errors of metabolism. The ability of oval cells to differentiate into hepatocytes has been demonstrated unequivocally. However, this process only occurs when the regenerative capacity of hepatocytes is overwhelmed, and thus, unlike the intestinal epithelium, the liver is not behaving as a classical continually renewing stem cell-fed lineage.
肝脏的再生能力已得到广泛认可，这通常是通过正常处于增殖静止状态的肝细胞进入细胞周期来实现的。然而，当肝细胞再生受损时，小胆管会增殖并侵入相邻的肝实质。在人类和实验动物中，这些导管细胞被称为卵圆细胞，它们与再生缺陷的关联导致人们认为它们是兼性干细胞的后代。卵圆细胞具有极大的生物学研究价值，因为它们可能是肝致癌物的靶细胞群体，也可能是用于纠正先天性代谢缺陷的体外基因治疗的有效载体。卵圆细胞分化为肝细胞的能力已得到明确证实。然而，这个过程只在肝细胞的再生能力不堪重负时才会发生，因此，与肠上皮不同，肝脏并非表现为典型的由干细胞持续供应的不断更新的谱系。
