title: Repetitive short-term bile duct obstruction and relief causes reproducible and reversible bile acid regurgitation.
abstract: BACKGROUND
  Long-term bile duct obstruction causes sinusoidal regurgitation of bile acids, a shift in bile acid metabolism, and alterations of liver histology. In this study we investigated the regurgitation of bile acids during short-term bile duct obstruction and its reversibility and reproducibility. In addition, the biotransformation of taurodeoxycholate and its appearance in bile and perfusate effluent were studied as well as liver histology.
  
  
  METHODS
  Rat livers (n = 5) were perfused in vitro with 32 nmol/min/g liver taurodeoxycholate over 85 min with the bile duct being intermittently closed for 30 and 20 min, respectively.
  
  
  RESULTS
  Within the first 5 min after bile duct obstruction bile acids started to regurgitate to the perfusate effluent amounting to approximately 15% of hepatic uptake until the end of the perfusion period. After relief of obstruction, bile flow and biliary bile acid excretion showed an overshoot phenomenon and were almost doubled compared to preobstruction. In contrast, sinusoidal bile acid regurgitation declined. The same phenomenon was observed during the second closure/opening cycle of the bile duct. Regurgitated bile acids consisted of significantly more taurodeoxycholate metabolites (approximately 70%) than did biliary bile acids (approximately 30%). Histology of liver parenchyma was preserved.
  
  
  CONCLUSIONS
  During repetitive short-term bile duct obstruction bile acid regurgitation is reversible and reproducible. The absence of altered mechanical barriers suggests that specific pathways are involved in the regurgitation process of bile acids.
authors.affiliation: Department of Surgery, University of Freiburg, Freiburg, Germany. baumgart@chir.ukl.uni-Freiburg.de <baumgart@chir.ukl.uni-Freiburg.de>
authors.forename: Ulrich
authors.initials: U
authors.lastname: Baumgartner
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schölmerich
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Feuerstein
authors.forename: Peter
authors.initials: P
authors.lastname: Baier
authors.forename: Christian
authors.initials: C
authors.lastname: Ihling
mesh_terms: D000208:Acute Disease; D000818:Animals; D001646:Bile / Q000378:metabolism; D001647:Bile Acids and Salts / Q000378:metabolism*; D001711:Biotransformation; D002756:Cholagogues and Choleretics / Q000493:pharmacokinetics; D002779:Cholestasis / Q000150:complications* / Q000378:metabolism* / Q000628:therapy; D005764:Gastroesophageal Reflux / Q000209:etiology*; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D013657:Taurodeoxycholic Acid / Q000493:pharmacokinetics
chemical_list: D001647:Bile Acids and Salts; D002756:Cholagogues and Choleretics; D013657:Taurodeoxycholic Acid