English: (a) Liver development in vivo. The liver cell lineage steps during hepatic development from definitive endoderm (DE) to functional adult hepatocytes and biliary epithelium. Hepatocytes, along with cholangiocytes (known as biliary epithelial cells) are derived from the DE (known as embryonic endoderm), while the stromal cells (stellate cells, Kupffer cells and blood vessels) are of mesodermal origin. (b) Directed differentiation of human ES cells into hepatocyte-like cells. To mimic the hepatic extracellular matrix, the human ES cells were plated on matrix (e.g. Matrigel, or collagen) and were treated with a series of growth factors and cytokines. The Activin A-treated human ES cells efficiently differentiate into DE cells. To mimic hepatic induction, FGF (fibroblast growth factor) and/ or BMP (bone morphogenetic protein) are added to the DE cells. This is followed by the combination of HGF (hepatocyte growth factor), OSM (oncostatin M), FGF and Dex (dexamethasone) to expand the hepatoblast population and to promote hepatic maturation.

English: Liver development and in vitro hepatic differentiation of embryonic stem cells