title: Acute ethanol causes hepatic mitochondrial depolarization in mice: role of ethanol metabolism.
abstract: OBJECTIVE
  An increase of ethanol metabolism and hepatic mitochondrial respiration occurs in vivo after a single binge of alcohol. Here, our aim was to determine how ethanol intake affects hepatic mitochondrial polarization status in vivo in relation to ethanol metabolism and steatosis.
  
  
  METHODS
  Hepatic mitochondrial polarization, permeability transition (MPT), and reduce pyridine nucleotides, and steatosis in mice were monitored by intravital confocal/multiphoton microscopy of the fluorescence of rhodamine 123 (Rh123), calcein, NAD(P)H, and BODIPY493/503, respectively, after gavage with ethanol (1-6 g/kg).
  
  
  RESULTS
  Mitochondria depolarized in an all-or-nothing fashion in individual hepatocytes as early as 1 h after alcohol. Depolarization was dose- and time-dependent, peaked after 6 to 12 h and maximally affected 94% of hepatocytes. This mitochondrial depolarization was not due to onset of the MPT. After 24 h, mitochondria of most hepatocytes recovered normal polarization and were indistinguishable from untreated after 7 days. Cell death monitored by propidium iodide staining, histology and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was low throughout. After alcohol, mitochondrial NAD(P)H autofluorescence increased and decreased, respectively, in hepatocytes with polarized and depolarized mitochondria. Ethanol also caused steatosis mainly in hepatocytes with depolarized mitochondria. Depolarization was linked to ethanol metabolism, since deficiency of alcohol dehydrogenase and cytochrome-P450 2E1 (CYP2E1), the major ethanol-metabolizing enzymes, decreased mitochondrial depolarization by ∼ 70% and ∼ 20%, respectively. Activation of aldehyde dehydrogenase decreased depolarization, whereas inhibition of aldehyde dehydrogenase enhanced depolarization. Activation of aldehyde dehydrogenase also markedly decreased steatosis.
  
  
  CONCLUSIONS
  Acute ethanol causes reversible hepatic mitochondrial depolarization in vivo that may contribute to steatosis and increased mitochondrial respiration. Onset of this mitochondrial depolarization is linked, at least in part, to metabolism of ethanol to acetaldehyde.
authors.affiliation: Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America; Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, United States of America.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhong
authors.affiliation: Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America; Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, United States of America.
authors.forename: Venkat K
authors.initials: VK
authors.lastname: Ramshesh
authors.affiliation: Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America.
authors.forename: Hasibur
authors.initials: H
authors.lastname: Rehman
authors.affiliation: Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America.
authors.forename: Qinlong
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America.
authors.forename: Tom P
authors.initials: TP
authors.lastname: Theruvath
authors.affiliation: Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America.
authors.forename: Yasodha
authors.initials: Y
authors.lastname: Krishnasamy
authors.affiliation: Department of Drug Discovery & Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America; Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America; Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina, United States of America.
authors.forename: John J
authors.initials: JJ
authors.lastname: Lemasters
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000426:Alcohol Dehydrogenase / Q000378:metabolism; D000818:Animals; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000378:metabolism* / Q000494:pharmacology; D005234:Fatty Liver / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress; D010539:Permeability
chemical_list: D027682:Cation Transport Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D000431:Ethanol; D000255:Adenosine Triphosphate; D003577:Cytochrome P-450 Enzyme System; D000426:Alcohol Dehydrogenase