Bone marrow–derived mesenchymal stem cells (BM-MSCs) represent an interesting alternative to liver or hepatocyte transplantation to treat liver injuries. Many studies have reported that MSCs can treat several diseases, including liver damage, just by injection into the bloodstream, without evidence of differentiation. The improvements were attributed to the organotrophic factors, low immunogenicity, immunomodulatory, and anti-inflammatory effects of MSCs, rather than their differentiation. The aim of the present study was to answer the question of whether the presence of BM-MSCs in the hepatic microenvironment will lead to their differentiation to functional hepatocyte-like cells. The hepatic microenvironment was mimicked in vitro by culture for 21 d with liver extract. The resulted cells expressed marker genes of the hepatic lineage including AFP, CK18, and Hnf4a. Functionally, they were able to detoxify ammonia into urea, to store glycogen as observed by PAS staining, and to synthesize glucose from pyruvate/lactate mixture. Phenotypically, the expression of MSC surface markers CD90 and CD105 decreased by differentiation. This evidenced differentiation into hepatocyte-like cells was accompanied by a downregulation of the stem cell marker genes sox2 and Nanog and the cell cycle regulatory genes ANAPC2, CDC2, Cyclin A1, and ABL1. The present results suggest a clear differentiation of BM-MSCs into functional hepatocyte-like cells by the extracted liver microenvironment. This differentiation is confirmed by a decrease in the stemness and mitotic activities. Tracking transplanted BM-MSCs and proving their in vivo differentiation remains to be elucidated.

骨髓来源的间充质干细胞（BM-MSC）代表了肝脏或肝细胞移植治疗肝损伤的一种有趣替代方法。许多研究报告称，仅通过注入血流，MSC就可以治疗多种疾病，包括肝损伤，而无分化迹象。改善归因于MSC的器官营养因子，低免疫原性，免疫调节和抗炎作用，而不是它们的分化。本研究的目的是回答肝微环境中BM-MSC的存在是否会导致它们分化为功能性肝细胞样细胞的问题。体外模拟肝微环境用肝提取物培养21天。产生的细胞表达肝谱系的标记基因，包括AFP，CK18和Hnf4a。从功能上讲，它们能够将氨解毒为尿素，通过PAS染色观察到可以存储糖原，并可以从丙酮酸盐/乳酸盐混合物中合成葡萄糖。表型上，MSC表面标志物CD90和CD105的表达通过分化而降低。这种分化为肝细胞样细胞的证据伴随着干细胞标记基因sox2和Nanog以及细胞周期调控基因ANAPC2，CDC2，Cyclin A1和ABL1的下调。。目前的结果表明，通过提取的肝脏微环境将BM-MSC明显分化为功能性肝细胞样细胞。这种分化可以通过降低茎和有丝分裂活性来确认。跟踪移植的BM-MSC并证明其体内分化仍有待阐明。