title: Liraglutide directly protects cardiomyocytes against reperfusion injury possibly via modulation of intracellular calcium homeostasis.
abstract: BACKGROUND
  Liraglutide is glucagon-like peptide-1 receptor agonist for treating patients with type 2 diabetes mellitus. Our previous studies have demonstrated that liraglutide protects cardiac function through improving endothelial function in patients with acute myocardial infarction undergoing percutaneous coronary intervention. The present study will investigate whether liraglutide can perform direct protective effects on cardiomyocytes against reperfusion injury.
  
  
  METHODS
  In vitroexperiments were performed using H9C2 cells and neonatal rat ventricular cadiomyocytes undergoing simulative hypoxia/reoxygenation (H/R) induction. Cardiomyocytes apoptosis was detected by fluorescence TUNEL. Mitochondrial membrane potential (ΔΨm) and intracellular reactive oxygen species (ROS) was assessed by JC-1 and DHE, respectively. Fura-2/AM was used to measure intracellular Ca2+concentration and calcium transient. Immunofluorescence staining was used to assess the expression level of sarcoplasmic reticulum Ca2+-ATPase (SERCA2a).In vivoexperiments, myocardial apoptosis and expression of SERCA2a were detected by colorimetric TUNEL and by immunofluorescence staining, respectively.
  
  
  RESULTS
  In vitroliraglutide inhibited cardiomyotes apoptosis against H/R.ΔΨm of cardiomyocytes was higher in liraglutide group than H/R group. H/R increased ROS production in H9C2 cells which was attenuated by liraglutide. Liraglutide significantly lowered Ca2+overload and improved calcium transient compared with H/R group. Immunofluorescence staining results showed liraglutide promoted SERCA2a expression which was decreased in H/R group. In ischemia/reperfusion rat hearts, apoptosis was significantly attenuated and SERCA2a expression was increased by liraglutide compared with H/R group.
  
  
  CONCLUSIONS
  Liraglutide can directly protect cardiomyocytes against reperfusion injury which is possibly through modulation of intracellular calcium homeostasis.
authors.affiliation: Department of Cardiology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Shun-Ying
authors.initials: SY
authors.lastname: Hu
authors.affiliation: Department of Cardiology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Ping-Jun
authors.initials: PJ
authors.lastname: Zhu
authors.affiliation: Department of Cardiology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Cardiology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Yun-Dai
authors.initials: YD
authors.lastname: Chen
keywords: Calcium overload; Cardiomyocyte; Liraglutide; Reperfusion injury; Sarcoplasmic reticulum Ca2+-ATPase