title: The role of dietary fatty acids in predicting myocardial structure in fat-fed rats.
abstract: BACKGROUND
  Obesity increases the risk for development of cardiomyopathy in the absence of hypertension, diabetes or myocardial ischemia. Not all obese individuals, however, progress to heart failure. Indeed, obesity may provide protection from cardiovascular mortality in some populations. The fatty acid milieu, modulated by diet, may modify obesity-induced myocardial structure and function, lending partial explanation for the array of cardiomyopathic phenotype in obese individuals.
  
  
  METHODS
  Adult male Sprague-Dawley rats were fed 1 of the following 4 diets for 32 weeks: control (CON); 50% saturated fat (SAT); 40% saturated fat + 10% linoleic acid (SAT+LA); 40% saturated fat + 10% α-linolenic acid (SAT+ALA). Serum leptin, insulin, glucose, free fatty acids and triglycerides were quantitated. In vivo cardiovascular outcomes included blood pressure, heart rate and echocardiographic measurements of structure and function. The rats were sacrificed and myocardium was processed for fatty acid analysis (TLC-GC), and evaluation of potential modifiers of myocardial structure including collagen (Masson's trichrome, hydroxyproline quantitation), lipid (Oil Red O, triglyceride quantitation) and myocyte cross sectional area.
  
  
  RESULTS
  Rats fed SAT+LA and SAT+ALA diets had greater cranial LV wall thickness compared to rats fed CON and SAT diets, in the absence of hypertension or apparent insulin resistance. Treatment was not associated with changes in myocardial function. Myocardial collagen and triglycerides were similar among treatment groups; however, rats fed the high-fat diets, regardless of composition, demonstrated increased myocyte cross sectional area.
  
  
  CONCLUSIONS
  Under conditions of high-fat feeding, replacement of 10% saturated fat with either LA or ALA is associated with thickening of the cranial LV wall, but without concomitant functional changes. Increased myocyte size appears to be a more likely contributor to early LV thickening in response to high-fat feeding. These findings suggest that myocyte hypertrophy may be an early change leading to gross LV hypertrophy in the hearts of "healthy" obese rats, in the absence of hypertension, diabetes and myocardial ischemia.
authors.affiliation: Department of Biomedical Sciences, Campus delivery #1680, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Kimberly M
authors.initials: KM
authors.lastname: Jeckel
authors.forename: Kelsey E
authors.initials: KE
authors.lastname: Miller
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Chicco
authors.forename: Phillip L
authors.initials: PL
authors.lastname: Chapman
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Mulligan
authors.forename: Paul H
authors.initials: PH
authors.lastname: Falcone
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Miller
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pagliassotti
authors.forename: Melinda A
authors.initials: MA
authors.lastname: Frye
mesh_terms: D050154:Adiposity / Q000187:drug effects; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D004452:Echocardiography; D005227:Fatty Acids / Q000008:administration & dosage / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects*; D006439:Hemodynamics / Q000187:drug effects; D006909:Hydroxyproline / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013347:Subcellular Fractions / Q000187:drug effects; D014280:Triglycerides / Q000378:metabolism
chemical_list: D004041:Dietary Fats; D005227:Fatty Acids; D010743:Phospholipids; D014280:Triglycerides; D006909:Hydroxyproline