Alcohol-related changes in the intestinal microbiome influence neutrophil infiltration, inflammation and steatosis in early alcoholic hepatitis in mice

• Published in: PloS one Vol. 12; no. 3; p. e0174544
• Main Authors: Lowe, Patrick P, Gyongyosi, Benedek, Satishchandran, Abhishek, Iracheta-Vellve, Arvin, Ambade, Aditya, Kodys, Karen, Catalano, Donna, Ward, Doyle V, Szabo, Gyongyi
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 28-03-2017; Public Library of Science (PLoS)
• Subjects: Alcohol use; Alcoholism; Alcohols; Analysis; Animals; Anti-Bacterial Agents - administration & dosage; Anti-Bacterial Agents - pharmacology; Antibiotics; Bacteria; Bacteria - classification; Bacteria - drug effects; Bacteria - genetics; Biology and Life Sciences; Care and treatment; Central Nervous System Depressants - administration & dosage; Central Nervous System Depressants - toxicity; Cytokines; Deoxyribonucleic acid; DNA; Ethanol; Ethanol - administration & dosage; Ethanol - toxicity; Fatty Liver - chemically induced; Fatty Liver - genetics; Fatty Liver, Alcoholic - etiology; Fatty Liver, Alcoholic - genetics; Female; Gastroenterology; Gastrointestinal Microbiome - drug effects; Gastrointestinal Microbiome - genetics; Gene expression; Gene Expression - drug effects; Health aspects; Hepatitis; Hepatitis, Alcoholic - etiology; Hepatitis, Alcoholic - genetics; Immunology; Infiltration; Inflammation; Inflammation - chemically induced; Inflammation - genetics; Intestinal microflora; Laboratories; Ligands; Lipids; Lipopolysaccharides; Liver; Liver - drug effects; Liver - metabolism; Liver - pathology; Liver diseases; Medical research; Medical schools; Medicine; Medicine and Health Sciences; Mice, Inbred C57BL; Microbiota (Symbiotic organisms); Neutrophil Infiltration - drug effects; Neutrophil Infiltration - genetics; Neutrophils; Physiological aspects; Research and Analysis Methods; Reverse Transcriptase Polymerase Chain Reaction; RNA, Ribosomal, 16S - genetics; Rodents; United States; United States > US; Massachusetts
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0174544

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.
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.
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 (Tnfα), 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).
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.