title: Protective role of HO-1 for alcohol-dependent liver damage.
abstract: OBJECTIVE
  Alcoholic liver disease is continuously increasing in developed countries being a leading cause of death worldwide. Chronic ethanol consumption induces oxidative stress by accumulation of reactive oxygen intermediates (ROI) while reducing the cellular antioxidant defense. Induction of heme oxygenase-1 (HO-1) may protect primary human hepatocytes (hHeps) from such damage. Thus, the aim of this study was to investigate the potential of polyphenols to protect hHeps from ethanol-dependent oxidative damage.
  
  
  METHODS
  hHeps were isolated by collagenase perfusion. ROI and cellular glutathione (GSH) were measured by fluorescent-based assays. Cellular damage was determined by lactate dehydrogenase (LDH) leakage and staining for apoptosis and necrosis. Nuclear translocation of Nrf2 and HO-1 expression were analyzed by Western blot.
  
  
  RESULTS
  Ethanol and TGF-β rapidly increase ROI and reduce GSH in hHeps, causing apoptosis with a release of approximately 40% total LDH after 72 h. Similar to incubation with hemin preincubation and co-incubation of cells with nifedipine, verapamil and quercetin significantly reduce oxidative stress and resulting cellular damage, in a dose-dependent manner, by initiating nuclear translocation of Nrf2 which in turn induces HO-1 under the control of p38 and ERK. Blocking of HO-1 activity with ZNPP9 reverses the protective effect of all three substances.
  
  
  CONCLUSIONS
  Our results suggest that increasing HO-1 activity in hHeps protects them from oxidative stress-dependent damage. As polyphenols have great potential to induce HO-1 expression, they may play an important role for future therapeutic strategies to protect liver from oxidative stress-dependent damage observed during chronic alcohol consumption.
authors.affiliation: Department of Traumatology, MRI, Technische Universität München, München, Germany. andreas.nuessler@gmail.com
authors.forename: A K
authors.initials: AK
authors.lastname: Nussler
authors.forename: L
authors.initials: L
authors.lastname: Hao
authors.forename: D
authors.initials: D
authors.lastname: Knobeloch
authors.forename: P
authors.initials: P
authors.lastname: Yao
authors.forename: N C
authors.initials: NC
authors.lastname: Nussler
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: L
authors.initials: L
authors.lastname: Liu
authors.forename: S
authors.initials: S
authors.lastname: Ehnert
mesh_terms: D002021:Buffers; D019610:Cytoprotection / Q000187:drug effects; D000431:Ethanol / Q000633:toxicity; D005419:Flavonoids / Q000494:pharmacology; D051547:Heme Oxygenase-1 / Q000378:metabolism*; D022781:Hepatocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008108:Liver Diseases, Alcoholic / Q000201:enzymology* / Q000473:pathology / Q000517:prevention & control*; D008954:Models, Biological; D018384:Oxidative Stress / Q000187:drug effects; D010636:Phenols / Q000494:pharmacology; D059808:Polyphenols; D020011:Protective Agents / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000633:toxicity; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D002021:Buffers; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D020011:Protective Agents; D016212:Transforming Growth Factor beta; D000431:Ethanol; D007770:L-Lactate Dehydrogenase; D051547:Heme Oxygenase-1