title: High fat diet enhances cardiac abnormalities in SHR rats: Protective role of heme oxygenase-adiponectin axis.
abstract: BACKGROUND
  High dietary fat intake is a major risk factor for development of cardiovascular and metabolic dysfunction including obesity, cardiomyopathy and hypertension.
  
  
  METHODS
  The present study was designed to examine effect of high fat (HF) diet on cardio-vascular structure and function in spontaneously hypertensive rats (SHR), fed HF diet for 15 weeks, a phenotype designed to mimic metabolic syndrome.
  
  
  RESULTS
  Development of metabolic syndrome like phenotype was confirmed using parameters, including body weight, total cholesterol and blood pressure levels. High fat diet impaired vascular relaxation by acetylcholine and exacerbated cardiac dysfunction in SHRs as evidenced by lower left ventricular function, and higher coronary resistance (CR) as compared to controls (p < 0.05). The histological examination revealed significant myocardial and peri-vascular fibrosis in hearts from SHRs on HF diet. This cardiac dysfunction was associated with increased levels of inflammatory cytokines, COX-2, NOX-2, TxB2 expression and increase in superoxide (O2-) levels in SHR fed a HF diet (p < 0.05). HO-1 induction via cobalt-protoporphyrin (CoPP,3 mg/kg), in HF fed rats, not only improved cardiac performance parameters, but also prevented myocardial and perivascular fibrosis. These effects of CoPP were accompanied by enhanced levels of cardiac adiponectin levels, pAMPK, peNOS and iNOS expression; otherwise significantly attenuated (p < 0.05) in HF fed SHRs. Prevention of such beneficial effects of CoPP by the concurrent administration of the HO inhibitor stannic mesoporphyrin (SnMP) corroborates the role of HO system in mediating such effects.
  
  
  CONCLUSIONS
  In conclusion, this novel study demonstrates that up-regulation of HO-1 improves cardiac and vascular dysfunction by blunting oxidative stress, COX-2 levels and increasing adiponectin levels in hypertensive rats on HF diet.
authors.affiliation: Department of Geriatric Cardiology, Chinese PLA General Hospital, Beijing 100853, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Cao
authors.affiliation: Department of Physiology and Pharmacology, College of Medicine, University of Toledo, Toledo, Ohio, 43614, USA.
authors.forename: Komal
authors.initials: K
authors.lastname: Sodhi
authors.affiliation: Department of Physiology and Pharmacology, College of Medicine, University of Toledo, Toledo, Ohio, 43614, USA.
authors.forename: Nitin
authors.initials: N
authors.lastname: Puri
authors.affiliation: Department of Physiology and Pharmacology, College of Medicine, University of Toledo, Toledo, Ohio, 43614, USA.
authors.forename: Sumit R
authors.initials: SR
authors.lastname: Monu
authors.affiliation: Department of Biomedical Science, Division of Anatomy, University of Brescia, Brescia Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Rezzani
authors.affiliation: Department of Physiology and Pharmacology, College of Medicine, University of Toledo, Toledo, Ohio, 43614, USA.
authors.forename: Nader G
authors.initials: NG
authors.lastname: Abraham