title: Chronic Alcohol Exposure Enhances Lipopolysaccharide-Induced Lung Injury in Mice: Potential Role of Systemic Tumor Necrosis Factor-Alpha.
abstract: BACKGROUND
  It is well known that liver and lung injury can occur simultaneously during severe inflammation (e.g., multiple organ failure). However, whether these are parallel or interdependent (i.e., liver-lung axis) mechanisms is unclear. Previous studies have shown that chronic ethanol (EtOH) consumption greatly increases mortality in the setting of sepsis-induced acute lung injury (ALI). The potential contribution of subclinical liver disease in driving this effect of EtOH on the lung remains unknown. Therefore, the purpose of this study was to characterize the impact of chronic EtOH exposure on concomitant liver and lung injury.
  
  
  METHODS
  Male mice were exposed to EtOH-containing Lieber-DeCarli diet or pair-fed control diet for 6 weeks. Some animals were administered lipopolysaccharide (LPS) 4 or 24 hours prior to sacrifice to mimic sepsis-induced ALI. Some animals received the tumor necrosis factor-alpha (TNF-α)-blocking drug, etanercept, for the duration of alcohol exposure. The expression of cytokine mRNA in lung and liver tissue was determined by quantitative PCR. Cytokine levels in the bronchoalveolar lavage fluid and plasma were determined by Luminex assay.
  
  
  RESULTS
  As expected, the combination of EtOH and LPS caused liver injury, as indicated by significantly increased levels of the transaminases alanine aminotransferase/aspartate aminotransferase in the plasma and by changes in liver histology. In the lung, EtOH preexposure enhanced pulmonary inflammation and alveolar hemorrhage caused by LPS. These changes corresponded with unique alterations in the expression of pro-inflammatory cytokines in the liver (i.e., TNF-α) and lung (i.e., macrophage inflammatory protein-2 [MIP-2], keratinocyte chemoattractant [KC]). Systemic depletion of TNF-α (etanercept) blunted injury and the increase in MIP-2 and KC caused by the combination of EtOH and LPS in the lung.
  
  
  CONCLUSIONS
  Chronic EtOH preexposure enhanced both liver and lung injury caused by LPS. Enhanced organ injury corresponded with unique changes in the pro-inflammatory cytokine expression profiles in the liver and the lung.
authors.affiliation: Department of Pharmacology and Toxicology, University of Louisville Health Sciences Center, Louisville, Kentucky.|University of Louisville Alcohol Research Center, Louisville, Kentucky.
authors.forename: Veronica L
authors.initials: VL
authors.lastname: Massey
authors.affiliation: Department of Pharmacology and Toxicology, University of Louisville Health Sciences Center, Louisville, Kentucky.|University of Louisville Alcohol Research Center, Louisville, Kentucky.
authors.forename: Lauren G
authors.initials: LG
authors.lastname: Poole
authors.affiliation: Department of Pharmacology and Toxicology, University of Louisville Health Sciences Center, Louisville, Kentucky.|University of Louisville Alcohol Research Center, Louisville, Kentucky.
authors.forename: Deanna L
authors.initials: DL
authors.lastname: Siow
authors.affiliation: Division of Pulmonary, Critical Care and Sleep Disorders Medicine, Department of Medicine, University of Louisville Health Sciences Center, Louisville, Kentucky.
authors.forename: Edilson
authors.initials: E
authors.lastname: Torres
authors.affiliation: Department of Micriobiology and Immunology, University of Louisville Health Sciences Center, Louisville, Kentucky.
authors.forename: Nikole L
authors.initials: NL
authors.lastname: Warner
authors.affiliation: Department of Pharmacology and Toxicology, University of Louisville Health Sciences Center, Louisville, Kentucky.|University of Louisville Alcohol Research Center, Louisville, Kentucky.
authors.forename: Robin H
authors.initials: RH
authors.lastname: Schmidt
authors.affiliation: Division of Pulmonary, Critical Care and Sleep Disorders Medicine, Department of Medicine, University of Louisville Health Sciences Center, Louisville, Kentucky.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Ritzenthaler
authors.affiliation: Division of Pulmonary, Critical Care and Sleep Disorders Medicine, Department of Medicine, University of Louisville Health Sciences Center, Louisville, Kentucky.
authors.forename: Jesse
authors.initials: J
authors.lastname: Roman
authors.affiliation: Department of Pharmacology and Toxicology, University of Louisville Health Sciences Center, Louisville, Kentucky.|University of Louisville Alcohol Research Center, Louisville, Kentucky.
authors.forename: Gavin E
authors.initials: GE
authors.lastname: Arteel
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D054426:Chemokine CXCL2 / Q000378:metabolism; D018925:Chemokines / Q000378:metabolism; D000068800:Etanercept / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology*; D008070:Lipopolysaccharides; D008099:Liver / Q000378:metabolism; D055370:Lung Injury / Q000139:chemically induced / Q000378:metabolism*; D008297:Male; D051379:Mice; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D054426:Chemokine CXCL2; D018925:Chemokines; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; C074302:keratinocyte-derived chemokines; D000431:Ethanol; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000068800:Etanercept
keywords: Acute Lung Injury; Alcohol; Alcoholic Liver Disease; Inflammation