title: The biliary HCO(3)(-) umbrella: experimental evidence revisited.
abstract: OBJECTIVE
  To critically review most recent experimental evidence for the protective action of biliary HCO(3)(-) secretion against bile acid-induced bile duct damage and development of fibrosing cholangiopathy in humans and experimental animals.
  
  
  RESULTS
  Studies in human cholangiocytes in vitro indicate that a biliary HCO(3)(-) umbrella protects against bile acid-induced cholangiocyte damage and apoptosis in humans. The Cl(-)/HCO(3)(-) exchanger, AE2, and an intact biliary glycocalyx appear crucial for its stability. Related studies with experimental animal models in vivo have to be interpreted with caution as humans and mice differ not only with regard to bile salt pool, but also their expression patterns of transport proteins and signalling molecules.
  
  
  CONCLUSIONS
  Adequate biliary HCO(3)(-) secretion may protect against bile salt-induced cholangiopathies. Future therapeutic strategies in biliary diseases will aim at stabilizing the biliary HCO(3)(-) umbrella.
authors.affiliation: Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. u.h.beuers@amc.uva.nl
authors.forename: Ulrich
authors.initials: U
authors.lastname: Beuers
authors.forename: Luca
authors.initials: L
authors.lastname: Maroni
authors.forename: Ronald O
authors.initials: RO
authors.lastname: Elferink
mesh_terms: D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology*; D001647:Bile Acids and Salts / Q000378:metabolism*; D001652:Bile Ducts / Q000378:metabolism*; D001659:Biliary Tract / Q000378:metabolism / Q000473:pathology*; D027963:Chloride-Bicarbonate Antiporters / Q000378:metabolism; D015209:Cholangitis, Sclerosing / Q000378:metabolism / Q000473:pathology*; D005355:Fibrosis; D006801:Humans; D051379:Mice
chemical_list: D001639:Bicarbonates; D001647:Bile Acids and Salts; D027963:Chloride-Bicarbonate Antiporters