title: The role of small intestinal bacterial overgrowth, intestinal permeability, endotoxaemia, and tumour necrosis factor alpha in the pathogenesis of non-alcoholic steatohepatitis.
abstract: BACKGROUND
  Small intestinal bacterial overgrowth may contribute to the development of non-alcoholic steatohepatitis, perhaps by increasing intestinal permeability and promoting the absorption of endotoxin or other enteric bacterial products.
  
  
  OBJECTIVE
  To investigate the prevalence of small intestinal bacterial overgrowth, increased intestinal permeability, elevated endotoxin, and tumour necrosis factor alpha (TNF-alpha) levels in patients with non-alcoholic steatohepatitis and in control subjects.
  
  
  METHODS
  Twenty two patients with non-alcoholic steatohepatitis and 23 control subjects were studied. Small intestinal bacterial overgrowth was assessed by a combined (14)C-D-xylose and lactulose breath test. Intestinal permeability was assessed by a dual lactulose-rhamnose sugar test. Serum endotoxin levels were determined using the limulus amoebocyte lysate assay and TNF-alpha levels using an ELISA.
  
  
  RESULTS
  Small intestinal bacterial overgrowth was present in 50% of patients with non-alcoholic steatosis and 22% of control subjects (p=0.048). Mean TNF-alpha levels in non-alcoholic steatohepatitis patients and control subjects were 14.2 and 7.5 pg/ml, respectively (p=0.001). Intestinal permeability and serum endotoxin levels were similar in the two groups.
  
  
  CONCLUSIONS
  Patients with non-alcoholic steatohepatitis have a higher prevalence of small intestinal bacterial overgrowth, as assessed by the (14)C-D-xylose-lactulose breath test, and higher TNF-alpha levels in comparison with control subjects. This is not accompanied by increased intestinal permeability or elevated endotoxin levels.
authors.affiliation: Department of Gastroenterology, Queen Elizabeth Hospital, Adelaide, South Australia, Australia. alan.wigg@flinders.edu.au
authors.forename: A J
authors.initials: AJ
authors.lastname: Wigg
authors.forename: I C
authors.initials: IC
authors.lastname: Roberts-Thomson
authors.forename: R B
authors.initials: RB
authors.lastname: Dymock
authors.forename: P J
authors.initials: PJ
authors.lastname: McCarthy
authors.forename: R H
authors.initials: RH
authors.lastname: Grose
authors.forename: A G
authors.initials: AG
authors.lastname: Cummins
mesh_terms: D000328:Adult; D001944:Breath Tests; D016022:Case-Control Studies; D019446:Endotoxemia / Q000150:complications* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005234:Fatty Liver / Q000209:etiology* / Q000378:metabolism; D005260:Female; D006505:Hepatitis / Q000209:etiology* / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000382:microbiology; D008033:Limulus Test; D008297:Male; D008875:Middle Aged; D010539:Permeability; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis*
chemical_list: D014409:Tumor Necrosis Factor-alpha