title: Adipocyte-derived factors suppress heart contraction.
abstract: BACKGROUND
  Obesity is strongly associated with cardiovascular diseases including systemic hypertension, coronary artery disease and heart failure. Despite several investigations the pathophysiological mechanisms involved remain unclear. We have previously shown that adipose tissue exerts a highly potent activity with an acute depressant effect on cardiomyocytes, thus suggesting direct involvement of adipose tissue in the development of heart dysfunction.
  
  
  OBJECTIVE
  This study investigates the effects of adipocyte factors obtained from subcutaneous adipose tissue on the whole cardiac function by using isolated perfused rat hearts in a Langendorff mode. We recorded changes in coronary flow, developed isovolumetric left ventricular pressure, contraction rate and relaxation rate.
  
  
  RESULTS
  We observed a significant decrease in heart contractility parameters as well as in coronary flow within a few seconds of incubation with adipocyte factors. The cardiodepressant effects could not be blocked by the nonselective cyclooxygenase-inhibitor indomethacin. Human adipocytes release tumor necrosis factor-α, interleukin-6 (IL-6) and IL-1β into extracellular medium. These cytokines were tested for their potential effect but were, however, not responsible for the cardiodepressant effect observed.
  
  
  CONCLUSIONS
  These data indicate that human adipocytes secrete factors with a strong acute depressant effect on cardiac force generation and coronary flow due to contraction of the coronary vessels, thus suggesting a direct role of adipose tissue in the pathogenesis of cardiac dysfunction.
authors.affiliation: Clinical Medicine III, University of Technology, Dresden, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Look
authors.forename: I
authors.initials: I
authors.lastname: Morano
authors.forename: M
authors.initials: M
authors.lastname: Ehrhart-Bornstein
authors.forename: S R
authors.initials: SR
authors.lastname: Bornstein
authors.forename: V
authors.initials: V
authors.lastname: Lamounier-Zepter
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D052436:Adipose Tissue, White / Q000473:pathology*; D000328:Adult; D000368:Aged; D000818:Animals; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D009765:Obesity / Q000150:complications / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D053583:Interleukin-1beta; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha