title: The role of intestinal microbiota in murine models of acetaminophen-induced hepatotoxicity.
abstract: OBJECTIVE
  Variations in intestinal microbiota may influence acetaminophen metabolism. This study aimed to determine whether intestinal microbiota are a source of differential susceptibility to acetaminophen-induced hepatotoxicity.
  
  
  METHODS
  Conventionally housed C3H/HeH (CH) and C3H/HeH germ-free (GF) mice were administered a 200 mg/kg IP dose of acetaminophen. The severity of hepatotoxicity at 8 h was assessed by histology and biochemical indices. A urinary metabolic profile was obtained using (1) H-NMR. Baseline hepatic glutathione content and CYP2E1 expression were quantified. An additional group of C3H/HeJ (LPS-r) mice were assessed to determine the contribution of LPS/TLR4 signalling.
  
  
  RESULTS
  Baseline glutathione levels were significantly reduced (P = 0.03) in GF mice. CYP2E1 mRNA expression and protein levels were not altered. Interindividual variability did not differ between GF and CH groups. No significant differences in the extent of hepatocellular injury (ALT or percentage necrosis) were demonstrated. However, a milder acute liver failure (ALF) phenotype was shown in GF compared with CH mice, with reduced plasma bilirubin and creatinine and increased blood glucose. Differential acetaminophen metabolism was demonstrated. GF mice displayed a higher urinary acetaminophen-sulphate:glucuronide ratio compared with CH (P = 0.01). Urinary analysis showed metabolic differentiation of GF and CH groups at baseline and 8 h (cross-validated anova P = 1 × 10(-22) ). Interruption of TLR4 signalling in LPS-r mice had additional protective effects.
  
  
  CONCLUSIONS
  Variations in intestinal microbiota do not fully explain differential susceptibility to acetaminophen-induced hepatotoxicity. GF mice experienced some protection from secondary complications following acetaminophen overdose and this may be mediated through reduced TLR4/LPS signalling.
authors.affiliation: Department of Hepatology, Imperial College, London, W2 1NY, UK.
authors.forename: Lucia A
authors.initials: LA
authors.lastname: Possamai
authors.forename: Mark Jw
authors.initials: MJ
authors.lastname: McPhail
authors.forename: Wafa
authors.initials: W
authors.lastname: Khamri
authors.forename: Bishan
authors.initials: B
authors.lastname: Wu
authors.forename: Danilo
authors.initials: D
authors.lastname: Concas
authors.forename: Mark
authors.initials: M
authors.lastname: Harrison
authors.forename: Roger
authors.initials: R
authors.lastname: Williams
authors.forename: Roger D
authors.initials: RD
authors.lastname: Cox
authors.forename: I Jane
authors.initials: IJ
authors.lastname: Cox
authors.forename: Quentin M
authors.initials: QM
authors.lastname: Anstee
authors.forename: Mark R
authors.initials: MR
authors.lastname: Thursz
mesh_terms: D000082:Acetaminophen / Q000633:toxicity*; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D056486:Chemical and Drug Induced Liver Injury / Q000382:microbiology / Q000503:physiopathology*; D019392:Cytochrome P-450 CYP2E1 / Q000097:blood; D016207:Cytokines / Q000097:blood; D004195:Disease Models, Animal; D005978:Glutathione / Q000097:blood; D007422:Intestines / Q000382:microbiology*; D008099:Liver / Q000473:pathology*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D064307:Microbiota; D066244:Proton Magnetic Resonance Spectroscopy
chemical_list: D016207:Cytokines; D000082:Acetaminophen; D019392:Cytochrome P-450 CYP2E1; D000410:Alanine Transaminase; D005978:Glutathione
keywords: acetaminophen; acute liver failure; germ-free; metabonomics; microbiota