title: Stereological characterization of left ventricular cardiomyocytes, capillaries, and innervation in the nondiabetic, obese mouse.
abstract: BACKGROUND
  Obesity is associated with left ventricular hypertrophy and dysfunction, but little is known about the structural remodeling of cardiomyocytes, capillaries, and nerve fibers in this state. We hypothesized that all three compartments should show quantitative structural alterations.
  
  
  METHODS
  Ten C57Bl6 mice were randomly assigned to a control or obesity group. Lean mice received standard chow, whereas obese mice received a high-fat Western diet. After 28 weeks, the mice were sacrificed, and the hearts were prepared for design-based stereology using light and electron microscopy.
  
  
  RESULTS
  Body mass and left ventricular mass were significantly elevated in obese vs. control mice. The left ventricular hypertrophy was accompanied by a significant increase in cardiomyocyte lipid droplets and total myocyte volume. The volume fractions of myofibrils, free sarcoplasm, and mitochondria did not differ between the groups. The total length of capillaries was significantly enhanced in obese vs. control mice, whereas the total length of axons ramifying between cardiomyocytes was not different.
  
  
  CONCLUSIONS
  Obesity is associated with significant structural alterations in cardiomyocytes and capillaries, whereas no structural changes in the myocardial innervation were observed. The structural characteristics in obese mice do not provide a clear basis for functional changes observed in obesity-related cardiac hypertrophy.
authors.affiliation: Institute of Anatomy and Cell Biology, Justus-Liebig-Universität Giessen, Aulweg 123, 35385 Giessen, Germany.
authors.forename: Carina
authors.initials: C
authors.lastname: Gruber
authors.forename: Karin
authors.initials: K
authors.lastname: Kohlstedt
authors.forename: Annemarieke E
authors.initials: AE
authors.lastname: Loot
authors.forename: Ingrid
authors.initials: I
authors.lastname: Fleming
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kummer
authors.forename: Christian
authors.initials: C
authors.lastname: Mühlfeld
mesh_terms: D000818:Animals; D001341:Autonomic Nervous System / Q000187:drug effects / Q000473:pathology; D001835:Body Weight / Q000187:drug effects; D002196:Capillaries / Q000187:drug effects / Q000473:pathology*; D059305:Diet, High-Fat; D006321:Heart / Q000187:drug effects; D006352:Heart Ventricles / Q000187:drug effects / Q000294:innervation / Q000473:pathology*; D017379:Hypertrophy, Left Ventricular / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology*; D050356:Lipid Metabolism / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D009206:Myocardium / Q000473:pathology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D009765:Obesity / Q000235:genetics; D009929:Organ Size / Q000187:drug effects