title: Acute alcohol modulates cardiac function as PI3K/Akt regulates oxidative stress.
abstract: BACKGROUND
  Clinical manifestations of alcohol abuse on the cardiac muscle include defective contractility with the development of heart failure. Interestingly, low alcohol consumption has been associated with reduced risk of cardiovascular disease. Although several hypotheses have been postulated for alcoholic cardiomyopathy and for the low-dose beneficial cardiovascular effects, the precise mechanisms and mediators remain largely undefined. We hypothesize that modulation of oxidative stress by PI3K/Akt plays a key role in the cardiac functional outcome to acute alcohol exposure.
  
  
  METHODS
  Thus, acutely exposed rat cardiac tissue and cardiocytes to low (LA: 5 mM), moderate (MA: 25 mM), and high (HA: 100 mM) alcohol were assessed for markers of oxidative stress in the presence and absence of PI3K/Akt activators (IGF-1 0.1 μM or constitutively active PI3K: Ad.BD110 transfection) or inhibitor (LY294002 1 μM or Akt-negative construct Ad.Akt(K179M) transfection).
  
  
  RESULTS
  Acute LA reduced Akt, superoxide dismutase (SOD-3) and NFκB, ERK1, and p38 MAPK gene expression. Acute HA only increased that of SOD-3 and NFκB. These effects were generally inhibited by Ad.Akt(K179M) and enhanced with Ad.BD110 transfection. In parallel, LA reduced but HA enhanced Akt activity, which was reversed by IGF-1 and inhibited by Ad.Akt(K179M), respectively. Also, LA reduced caspase 3/7 activity and oxidative stress, while HA increased both. The former was blocked, while the latter effect was enhanced by Ad.Akt(K179M). The reverse was true with PI3K/Akt activation. This translated into reduced viability with HA, with no effect with LA. On the functional level, acute LA improved cardiac output and ejection fraction, mainly through increased stroke volume. This was accompanied with enhanced end-systolic pressure-volume relationship and preload recruitable stroke work. Opposite effect was recorded for HA. LA and HA in vivo functional effects were alleviated by LY and enhanced by IGF-1 treatment.
  
  
  CONCLUSIONS
  Acute LA and HA seem to oppositely affect cardiac function through modulation of oxidative stress where PI3K/Akt plays a pivotal role.
authors: Department of Physiology & Biophysics, College of Medicine, Howard University, Washington, District of Columbia.
authors: Nsini A
authors: NA
authors: Umoh
authors: Robin K
authors: RK
authors: Walker
authors: Mustafa
authors: M
authors: Al-Rubaiee
authors: Miara A
authors: MA
authors: Jeffress
authors: Georges E
authors: GE
authors: Haddad
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002867:Chromones / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000008:administration & dosage* / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D009206:Myocardium / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D055647:Rats, Transgenic; D015398:Signal Transduction / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D015415:Biomarkers; D002867:Chromones; D000431:Ethanol; D007334:Insulin-Like Growth Factor I; D020928:Mitogen-Activated Protein Kinases; D009025:Morpholines; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D013482:Superoxide Dismutase; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
keywords: Akt; Alcohol; Cardiac; Contractility; Oxidative Stress; PI3K