title: Combined remote perconditioning and postconditioning failed to attenuate infarct size and contractile dysfunction in a rat model of coronary artery occlusion.
abstract: OBJECTIVE
  Although preconditioning remains one of the most powerful maneuvers to reduce myocardial infarct size, it is not feasible in the clinical setting to pretreat patients prior to acute myocardial infarction (MI). The purpose of this study was to investigate the effect of more clinically relevant therapies of remote perconditioning, postconditioning, and the combined effect of remote perconditioning and postconditioning on myocardial infarct size in an anesthetized rat model.
  
  
  METHODS
  Anesthetized rats were subjected to 45 minutes of proximal left coronary artery occlusion followed by 2 hours of reperfusion. Remote perconditioning was performed 5 minutes after left coronary occlusion with 4 cycles of 5 minutes of occlusion and reperfusion of both the femoral arteries. Postconditioning was applied immediately prior to 2 hours of full reperfusion with 6 cycles of 10 seconds occlusion-reperfusion of the coronary artery. The combined effect was produced by preceding the postconditioning regimen with remote perconditioning, after 5 minutes of left coronary occlusion.
  
  
  RESULTS
  Remote perconditioning and postconditioning alone failed to reduce infarct size expressed as percentage of the risk zone (42.2% ± 3.9% and 45.0% ± 4.3%). The combination of remote perconditioning and postconditioning also failed to reduce infarct size (45.3% ± 4.1%) as compared to the untreated ischemia-reperfusion group (48.7% ± 3.4%). Hemodynamics including left ventricular end-systole and end-diastolic pressures, +dP/dt, -dP/dt, and heart rate did not show any improvement in the conditioning groups.
  
  
  CONCLUSIONS
  This study shows that remote perconditioning and postconditioning alone or combined neither improve hemodynamics nor reduce infarct size in the rat model of MI.
authors.affiliation: The Heart Institute of Good Samaritan Hospital, and Division of Cardiovascular Medicine of the Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Jaspreet
authors.initials: J
authors.lastname: Sachdeva
authors.affiliation: The Heart Institute of Good Samaritan Hospital, and Division of Cardiovascular Medicine of the Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Wangde
authors.initials: W
authors.lastname: Dai
authors.affiliation: The Heart Institute of Good Samaritan Hospital, and Division of Cardiovascular Medicine of the Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Paul Z
authors.initials: PZ
authors.lastname: Gerczuk
authors.affiliation: The Heart Institute of Good Samaritan Hospital, and Division of Cardiovascular Medicine of the Keck School of Medicine, University of Southern California, Los Angeles, CA, USA rkloner@goodsam.org.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kloner
mesh_terms: D000818:Animals; D054059:Coronary Occlusion / Q000150:complications / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D004195:Disease Models, Animal; D005260:Female; D006339:Heart Rate; D006614:Hindlimb; D057775:Ischemic Postconditioning / Q000379:methods*; D019194:Ischemic Preconditioning / Q000379:methods*; D018482:Muscle, Skeletal / Q000098:blood supply*; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D009206:Myocardium / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D016277:Ventricular Function, Left; D017725:Ventricular Pressure
keywords: ischemia–reperfusion; postconditioning; remote perconditioning