FIGURE 1.

Scheme of liver organoid formation. Adult stem cells (ASCs), primary hepatocytes, or cholangiocytes could be obtained from primary liver tissue, intrahepatic/extrahepatic bile duct, gallbladder, or human bile by means of surgical resection, needle biopsy, and endoscope brushing. After mechanical or enzymatic dissociation, single hepatocytes or cholangiocytes are plated on ECM that contains exclusive growth factors and chemical molecules. In addition, liver organoids can be derived from PSCs, including iPSCs and ESCs. PSCs are firstly induced into definitive endoderm and then into hepatoblasts, which can differentiate into hepatocyte or cholangiocyte organoids with careful modulation of specific signaling pathway modeling liver development (relative growth factors in the medium are listed above). Abbreviations: BMP4, bone morphogenetic protein 4; ESCs, embryonic stem cells; iPSCs, induced pluripotent stem cells; PSCs, pluripotent stem cells.