title: Isolation and characterization of a stem cell population from adult human liver.
abstract: Several studies suggested the presence of stem cells in the adult normal human liver; however, a population with stem cell properties has not yet been isolated. The purpose of the present study was to identify and characterize progenitor cells in normal adult human liver. By stringent conditions of liver cell cultures, we isolated and characterized a population of human liver stem cells (HLSCs). HLSCs expressed the mesenchymal stem cell markers CD29, CD73, CD44, and CD90 but not the hematopoietic stem cell markers CD34, CD45, CD117, and CD133. HLSCs were also positive for vimentin and nestin, a stem cell marker. The absence of staining for cytokeratin-19, CD117, and CD34 indicated that HLSCs were not oval stem cells. In addition, HLSCs expressed albumin, alpha-fetoprotein, and in a small percentage of cells, cytokeratin-8 and cytokeratin-18, indicating a partial commitment to hepatic cells. HLSCs differentiated in mature hepatocytes when cultured in the presence of hepatocyte growth factor and fibroblast growth factor 4, as indicated by the expression of functional cytochrome P450, albumin, and urea production. Under this condition, HLSCs downregulated alpha-fetoprotein and expressed cytokeratin-8 and cytokeratin-18. HLSCs were also able to undergo osteogenic and endothelial differentiation when cultured in the appropriated differentiation media, but they did not undergo lipogenic differentiation. Moreover, HLSCs differentiated in insulin-producing islet-like structures. In vivo, HLSCs contributed to regeneration of the liver parenchyma in severe-combined immunodeficient mice. In conclusion, we here identified a pluripotent progenitor population in adult human liver that could provide a basis for cell therapy strategies.
authors.affiliation: Department of Internal Medicine, University of Torino, Torino, Italy.
authors.forename: Maria Beatriz
authors.initials: MB
authors.lastname: Herrera
authors.forename: Stefania
authors.initials: S
authors.lastname: Bruno
authors.forename: Stefano
authors.initials: S
authors.lastname: Buttiglieri
authors.forename: Ciro
authors.initials: C
authors.lastname: Tetta
authors.forename: Stefano
authors.initials: S
authors.lastname: Gatti
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Deregibus
authors.forename: Benedetta
authors.initials: B
authors.lastname: Bussolati
authors.forename: Giovanni
authors.initials: G
authors.lastname: Camussi
mesh_terms: D050156:Adipogenesis; D000328:Adult; D053687:Adult Stem Cells / Q000166:cytology* / Q000648:ultrastructure; D000818:Animals; D002469:Cell Separation / Q000379:methods*; D003114:Colony-Forming Units Assay; D042783:Endothelial Cells / Q000166:cytology; D005347:Fibroblasts / Q000166:cytology; D005434:Flow Cytometry; D022781:Hepatocytes / Q000166:cytology / Q000648:ultrastructure; D006801:Humans; D016130:Immunophenotyping; D007515:Islets of Langerhans / Q000166:cytology; D007700:Kinetics; D008099:Liver / Q000166:cytology* / Q000648:ultrastructure; D008115:Liver Regeneration; D051379:Mice; D016513:Mice, SCID; D010012:Osteogenesis