BACKGROUND: Emerging evidence suggests that "adaptive" induction of autophagy (the cellular process responsible for the degradation and recycling of proteins and organelles) may confer a cardioprotective phenotype and represent a novel strategy to limit ischemia-reperfusion injury. Our aim was to test this paradigm in a clinically relevant, large animal model of acute myocardial infarction. METHODS AND RESULTS: Anesthetized pigs underwent 45 minutes of coronary artery occlusion and 3 hours of reperfusion. In the first component of the study, pigs received chloramphenicol succinate (CAPS) (an agent that purportedly upregulates autophagy; 20 mg/kg) or saline at 10 minutes before ischemia. Infarct size was delineated by tetrazolium staining and expressed as a % of the at-risk myocardium. In separate animals, myocardial samples were harvested at baseline and 10 minutes following CAPS treatment and assayed (by immunoblotting) for 2 proteins involved in autophagosome formation: Beclin-1 and microtubule-associated protein light chain 3-II. To investigate whether the efficacy of CAPS was maintained with "delayed" treatment, additional pigs received CAPS (20 mg/kg) at 30 minutes after occlusion. Expression of Beclin-1 and microtubule-associated protein light chain 3-II, as well as infarct size, were assessed at end-reperfusion. CAPS was cardioprotective: infarct size was 25±5 and 41±4%, respectively, in the CAPS-pretreated and CAPS-delayed treatment groups versus 56±5% in saline controls (P<0.01 and P<0.05 versus control). Moreover, administration of CAPS was associated with increased expression of both proteins. CONCLUSIONS: Our results demonstrate attenuation of ischemia-reperfusion injury with CAPS and are consistent with the concept that induction of autophagy may provide a novel strategy to confer cardioprotection.
BACKGROUND: Emerging evidence suggests that "adaptive" induction of autophagy (the cellular process responsible for the degradation and recycling of proteins and organelles) may confer a cardioprotective phenotype and represent a novel strategy to limit ischemia-reperfusion injury. Our aim was to test this paradigm in a clinically relevant, large animal model of acute myocardial infarction. METHODS AND RESULTS: Anesthetized pigs underwent 45 minutes of coronary artery occlusion and 3 hours of reperfusion. In the first component of the study, pigs received chloramphenicol succinate (CAPS) (an agent that purportedly upregulates autophagy; 20 mg/kg) or saline at 10 minutes before ischemia. Infarct size was delineated by tetrazolium staining and expressed as a % of the at-risk myocardium. In separate animals, myocardial samples were harvested at baseline and 10 minutes following CAPS treatment and assayed (by immunoblotting) for 2 proteins involved in autophagosome formation: Beclin-1 and microtubule-associated protein light chain 3-II. To investigate whether the efficacy of CAPS was maintained with "delayed" treatment, additional pigs received CAPS (20 mg/kg) at 30 minutes after occlusion. Expression of Beclin-1 and microtubule-associated protein light chain 3-II, as well as infarct size, were assessed at end-reperfusion. CAPS was cardioprotective: infarct size was 25±5 and 41±4%, respectively, in the CAPS-pretreated and CAPS-delayed treatment groups versus 56±5% in saline controls (P<0.01 and P<0.05 versus control). Moreover, administration of CAPS was associated with increased expression of both proteins. CONCLUSIONS: Our results demonstrate attenuation of ischemia-reperfusion injury with CAPS and are consistent with the concept that induction of autophagy may provide a novel strategy to confer cardioprotection.
Authors: Smadar Yitzhaki; Chengqun Huang; Wayne Liu; Youngil Lee; Asa B Gustafsson; Robert M Mentzer; Roberta A Gottlieb Journal: Basic Res Cardiol Date: 2009-02-26 Impact factor: 17.165
Authors: Hongxin Zhu; Paul Tannous; Janet L Johnstone; Yongli Kong; John M Shelton; James A Richardson; Vien Le; Beth Levine; Beverly A Rothermel; Joseph A Hill Journal: J Clin Invest Date: 2007-07 Impact factor: 14.808
Authors: Zoltán Giricz; Zoltán V Varga; Gábor Koncsos; Csilla Terézia Nagy; Anikó Görbe; Robert M Mentzer; Roberta A Gottlieb; Péter Ferdinandy Journal: Life Sci Date: 2017-08-01 Impact factor: 5.037
Authors: Min Xie; Yongli Kong; Wei Tan; Herman May; Pavan K Battiprolu; Zully Pedrozo; Zhao V Wang; Cyndi Morales; Xiang Luo; Geoffrey Cho; Nan Jiang; Michael E Jessen; John J Warner; Sergio Lavandero; Thomas G Gillette; Aslan T Turer; Joseph A Hill Journal: Circulation Date: 2014-01-06 Impact factor: 29.690