OBJECTIVETo study the role of a pathologic niche inducing mouse embryonic stem cells (ESC) to express hepatic cell functions in vitro.

METHODSEmbryoid bodies were developed from 5 to 7 day hanging-drop culture of mouse ESC, and their dissociated cells were planted in three differential systems: nothing added; with 20 ng/ml hepatocyte growth factor (HGF); and 5% rat cholestatic serum plus 20 ng/ml HGF added. Their differentiation was observed with inverted microscopes daily, and their hepatic functions were analyzed against their synthesis of glycogen, triglycerides, albumin, and urea nitrogen, and by their staining of indocyanine green (ICG) and fluorescein diacetate (FDA).

RESULTSESC spontaneous differentiation was hardly being controlled to form three germ layers. HGF prompted the ESC to develop further into visceral endoderm and mesoderm (myocardium), but both of them only expressed a low level of hepatocyte-specific metabolic functions. With cholestatic serum added into the HGF-induced system, differentiated cells grew into similar angular cells, and had a higher level synthesis of glycogen, triglycerides, albumin and urea nitrogen with positive ICG and FDA staining.

CONCLUSIONSSpontaneous or HGF-induced ESC differentiation has only limited hepatic functions expressed. A pathologic niche in vitro induces ESC to develop into hepatic lineages, with a higher level of hepatic metabolic functions.