In vitro hepatic differentiation of human endometrial stromal stem cells.

Human endometrial stromal stem cells (hESSCs) can differentiate into mesodermal and ectodermal cellular lineages in the endometrium. However, whether hESSCs can differentiate into functional hepatic-like cells is unknown. In this study, we developed a multiple-step induction protocol to differentiate hESSCs into functional hepatic-like cells in vitro. Endometrial stromal cells were isolated by magnetic affinity sorting using anti-epithelial cell adhesion molecule-coated Dynabeads. The enriched hESSCs were analyzed by flow cytometry and were able to differentiate into osteoblasts or adipocytes under proper induction media. To differentiate into hepatic-like cells, hESSCs were cultured in a stepwise system containing hepatocyte growth factor, fibroblast growth factor-4, oncostatin M, and trichostatin A for a total of 24 d. The hepatic-like cell differentiation was analyzed by confocal microscopy and immunocytochemical staining. Glycogen storage, cellular urea synthesis, and ammonia concentrations were measured. Hepatic-like cells were successfully generated from hESSCs and were identified by their epithelial-like shape characteristics and expression of specific biomarkers albumin and cytokeratin 8 accompanied with a reduction of alpha-fetoprotein and alpha-smooth muscle actin expression. The hepatic-like cells generated were functional as evidenced by urea synthesis and glycogen storage. Our study demonstrated that hESSCs were able to differentiate into hepatic-like cells in vitro. Thus, endometrial stromal cells may be used as an easily accessible alternative source of stem cells for potential therapeutic applications in liver disease.