title: Chronic high-fat diet-induced obesity decreased survival and increased hypertrophy of rats with experimental eccentric hypertrophy from chronic aortic regurgitation.
abstract: BACKGROUND
  The composition of a diet can influence myocardial metabolism and development of left ventricular hypertrophy (LVH). The impact of a high-fat diet in chronic left ventricular volume overload (VO) causing eccentric LVH is unknown. This study examined the effects of chronic ingestion of a high-fat diet in rats with chronic VO caused by severe aortic valve regurgitation (AR) on LVH, function and on myocardial energetics and survival.
  
  
  METHODS
  Male Wistar rats were divided in four groups: Shams on control or high-fat (HF) diet (15 rats/group) and AR rats fed with the same diets (ARC (n = 56) and ARHF (n = 32)). HF diet was started one week before AR induction and the protocol was stopped 30 weeks later.
  
  
  RESULTS
  As expected, AR caused significant LV dilation and hypertrophy and this was exacerbated in the ARHF group. Moreover, survival in the ARHF group was significantly decreased compared the ARC group. Although the sham animals on HF also developed significant obesity compared to those on control diet, this was not associated with heart hypertrophy. The HF diet in AR rats partially countered the expected shift in myocardial energy substrate preference usually observed in heart hypertrophy (from fatty acids towards glucose). Systolic function was decreased in AR rats but HF diet had no impact on this parameter. The response to HF diet of different fatty acid oxidation markers as well as the increase in glucose transporter-4 translocation to the plasma membrane compared to ARC was blunted in AR animals compared to those on control diet.
  
  
  CONCLUSIONS
  HF diet for 30 weeks decreased survival of AR rats and worsened eccentric hypertrophy without affecting systolic function. The expected adaptation of myocardial energetics to volume-overload left ventricle hypertrophy in AR animals seemed to be impaired by the high-fat diet suggesting less metabolic flexibility.
authors.forename: Wahiba
authors.initials: W
authors.lastname: Dhahri
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Drolet
authors.forename: Elise
authors.initials: E
authors.lastname: Roussel
authors.affiliation: Groupe de Recherche en Valvulopathies, Centre de Recherche, Institut universitaire de cardiologie et de pneumologie de Québec, 2725, Chemin Sainte-Foy, Quebec City, Quebec G1V 4G5, Canada. jacques.couet@med.ulaval.ca.
authors.forename: Jacques
authors.initials: J
authors.lastname: Couet
authors.forename: Marie
authors.initials: M
authors.lastname: Arsenault
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001022:Aortic Valve Insufficiency / Q000150:complications* / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology; D059305:Diet, High-Fat / Q000009:adverse effects*; D004195:Disease Models, Animal; D004734:Energy Metabolism; D005227:Fatty Acids / Q000378:metabolism; D051858:Forkhead Transcription Factors / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D017379:Hypertrophy, Left Ventricular / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D009206:Myocardium / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009765:Obesity / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D010084:Oxidation-Reduction; D017208:Rats, Wistar; D012307:Risk Factors; D013997:Time Factors; D016277:Ventricular Function, Left; D000071161:Forkhead Box Protein O1
chemical_list: D005227:Fatty Acids; D051858:Forkhead Transcription Factors; D005947:Glucose; D051275:Glucose Transporter Type 4; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D009419:Nerve Tissue Proteins; C495694:Slc2a4 protein, rat; C074639:Foxo1 protein, rat; D000071161:Forkhead Box Protein O1