Hexarelin treatment preserves myocardial function and reduces cardiac fibrosis in a mouse model of acute myocardial infarction

Physiol Rep. 2018 May;6(9):e13699. doi: 10.14814/phy2.13699.


Ischemic heart disease (IHD) is a leading cause of morbidity and mortality worldwide. Growth hormone secretagogues (GHS) have been shown to improve cardiac function in models of IHD. This study determined whether hexarelin (HEX), a synthetic GHS, preserves cardiac function and morphology in a mouse model of myocardial infarction (MI). MI was induced by ligation of the left descending coronary artery in C57BL/6J mice followed by vehicle (VEH; n = 10) or HEX (0.3 mg/kg/day; n = 11) administration for 21 days. MI-injured and sham mice (treated with VEH; n = 6 or HEX; n = 5) underwent magnetic resonance imaging for measurement of left ventricular (LV) function, mass and infarct size at 24 h and 14 days post-MI. MI-HEX mice displayed a significant improvement (P < 0.05) in LV function compared with MI-VEH mice after 14 days treatment. A significant decrease in LV mass, interstitial collagen and collagen concentration was demonstrated with chronic HEX treatment (for 21 days), accompanied by a decrease in TGF-β1 expression, myofibroblast differentiation and an increase in collagen-degrading MMP-13 expression levels. Furthermore, heart rate variability analysis demonstrated that HEX treatment shifted the balance of autonomic nervous activity toward a parasympathetic predominance and sympathetic downregulation. This was combined with a HEX-dependent decrease in troponin-I, IL-1β and TNF-α levels suggestive of amelioration of cardiomyocyte injury. These results demonstrate that GHS may preserve ventricular function, reduce inflammation and favorably remodel the process of fibrotic healing in a mouse model of MI and hold the potential for translational application to patients suffering from MI.

Keywords: Fibrosis; heart failure; ischemia; myocardial infarction; remodeling.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Pressure
  • Disease Models, Animal
  • Fibrosis
  • Heart / drug effects*
  • Heart / physiopathology
  • Inflammation / complications
  • Inflammation / metabolism
  • Male
  • Mice, Inbred C57BL
  • Myocardial Infarction / etiology
  • Myocardial Infarction / pathology*
  • Myocardial Infarction / physiopathology*
  • Myocardium / pathology
  • Oligopeptides / administration & dosage*
  • Ventricular Remodeling / drug effects


  • Oligopeptides
  • hexarelin