Department of Medicine, Division of Gastroenterology; Center for Microbiome Research; Department of Microbiology and Physiological Systems; Graduate School of Biomedical Sciences, Translational Science Program; UMass Metabolic Network
Cell Biology | Cellular and Molecular Physiology | Digestive System Diseases | Gastroenterology | Hepatology
BACKGROUND: Alcohol-induced intestinal dysbiosis disrupts homeostatic gut-liver axis function and is essential in the development of alcoholic liver disease. Here, we investigate changes in enteric microbiome composition in a model of early alcoholic steatohepatitis and dissect the pathogenic role of intestinal microbes in alcohol-induced liver pathology.
MATERIALS AND METHODS: Wild type mice received a 10-day diet that was either 5% alcohol-containing or an isocaloric control diet plus a single binge. 16S rDNA sequencing defined the bacterial communities in the cecum of alcohol- and pair-fed animals. Some mice were treated with an antibiotic cocktail prior to and throughout alcohol feeding. Liver neutrophils, cytokines and steatosis were evaluated.
RESULTS: Acute-on-chronic alcohol administration induced shifts in various bacterial phyla in the cecum, including increased Actinobacteria and a reduction in Verrucomicrobia driven entirely by a reduction in the genus Akkermansia. Antibiotic treatment reduced the gut bacterial load and circulating bacterial wall component lipopolysaccharide (LPS). We found that bacterial load suppression prevented alcohol-related increases in the number of myeloperoxidase- (MPO) positive infiltrating neutrophils in the liver. Expression of liver mRNA tumor necrosis factor alpha (Tnfalpha), C-X-C motif chemokine ligand 1 (Cxcl1) and circulating protein monocyte chemoattractant protein-1 (MCP-1) were also reduced in antibiotic-treated alcohol-fed mice. Alcohol-induced hepatic steatosis measured by Oil-Red O staining was significantly reduced in antibiotic treated mice. Genes regulating lipid production and storage were also altered by alcohol and antibiotic treatment. Interestingly, antibiotic treatment did not protect from alcohol-induced increases in serum aminotransferases (ALT/AST).
CONCLUSIONS: Our data indicate that acute-on-chronic alcohol feeding alters the microflora at multiple taxonomic levels and identifies loss of Akkermansia as an early marker of alcohol-induced gut dysbiosis. We conclude that gut microbes influence liver inflammation, neutrophil infiltration and liver steatosis following alcohol consumption and these data further emphasize the role of the gut-liver axis in early alcoholic liver disease.
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Copyright: © 2017 Lowe et al. Citation: PLoS One. 2017 Mar 28;12(3):e0174544. doi: 10.1371/journal.pone.0174544. eCollection 2017. Link to article on publisher's site
Lowe, Patrick; Gyongyosi, Benedek; Satishchandran, Abhishek; Iracheta-Vellve, Arvin; Ambade, Aditya; Kodys, Karen; Catalano, Donna; Ward, Doyle V.; and Szabo, Gyongyi, "Alcohol-related changes in the intestinal microbiome influence neutrophil infiltration, inflammation and steatosis in early alcoholic hepatitis in mice" (2017). University of Massachusetts Medical School Faculty Publications. 1193.
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