title: Induction of autophagy restores the loss of sevoflurane cardiac preconditioning seen with prolonged ischemic insult.
abstract: Sevoflurane preconditioning against myocardial ischemia-reperfusion injury is lost if the ischemic insult is too long. Emerging evidence suggests that induction of autophagy may also confer cardioprotection against ischemia-reperfusion injury. We examined whether induction of autophagy prolongs sevoflurane preconditioning protection during a longer ischemic insult. Isolated guinea pigs hearts were subjected to 30 or 45 min ischemia, followed by 120 min reperfusion (control). Anesthetic preconditioning was elicited with 2% sevoflurane for 10 min prior to ischemia (SEVO-30, SEVO-45). Chloramphenicol (autophagy upregulator, 300 µM) was administered starting 20 min before ischemia and throughout reperfusion in SEVO-45 (SEVO-45+CAP). To inhibit autophagy, 3-methyladenine (10 μM) was administered during sevoflurane administration in SEVO-45+CAP. Infarct size was determined by triphenyltetrazolium chloride stain. Tissue samples were obtained before ischemia to determine autophagy-related protein (microtubule-associated protein light chain I and II: LC3-I, II), Akt and glycogen synthase kinase 3β (GSK3β) expression using Western blot analysis. The effect of autophagy on calcium-induced mitochondrial permeability transition pore (MPTP) opening in isolated calcein-loaded mitochondria was assessed. Electron microscopy was used to detect autophagosomes. Infarct size was significantly reduced in SEVO-30, but not in SEVO-45. Chloramphenicol restored sevoflurane preconditioning lost by 45 min ischemia. There were more abundant autophagozomes and LC3-II expression was significantly increased in SEVO-45+CAP. Induction of autophagy before ischemia enhanced GSK3β phosphorylation and inhibition of calcium-induced MPTP opening. These effects were abolished by 3-methyladenine. Pre-ischemic induction of autophagy restores sevoflurane preconditioning lost by longer ischemic insult. This effect is associated with enhanced inhibition of MPTP by autophagy.
authors.affiliation: Department of Anesthesiology, Osaka Medical College, Osaka, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Shiomi
authors.affiliation: Department of Internal Medicine, Osaka Dental University, 8-1 Kuzuha hanazono-cho Hirakata, Osaka 573-1121, Japan. Electronic address: miyamae0907@gmail.com.
authors.forename: Masami
authors.initials: M
authors.lastname: Miyamae
authors.affiliation: Department of Cardiology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Genzou
authors.initials: G
authors.lastname: Takemura
authors.affiliation: Department of Anesthesiology, Osaka Dental University, Osaka, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kaneda
authors.affiliation: Department of Anesthesiology, Osaka Dental University, Osaka, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Inamura
authors.affiliation: Department of Anesthesiology, Osaka Dental University, Osaka, Japan.
authors.forename: Anna
authors.initials: A
authors.lastname: Onishi
authors.affiliation: Department of Anesthesiology, Osaka Dental University, Osaka, Japan.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Koshinuma
authors.affiliation: Department of Anesthesiology, Osaka Dental University, Osaka, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Momota
authors.affiliation: Department of Anesthesiology, Osaka Medical College, Osaka, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Minami
authors.affiliation: Institute for Heart and Vascular Health, Einstein Medical Center, and Jefferson Medical College, Philadelphia, USA.
authors.forename: Vincent M
authors.initials: VM
authors.lastname: Figueredo
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D001343:Autophagy; D002316:Cardiotonic Agents / Q000494:pharmacology*; D002701:Chloramphenicol / Q000494:pharmacology*; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D046529:Microscopy, Electron, Transmission; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008929:Mitochondria, Heart; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D002316:Cardiotonic Agents; D008738:Methyl Ethers; D008869:Microtubule-Associated Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D000077149:Sevoflurane; C025946:3-methyladenine; D002701:Chloramphenicol; D000071679:Glycogen Synthase Kinase 3 beta; D051057:Proto-Oncogene Proteins c-akt; D038362:Glycogen Synthase Kinase 3; D000225:Adenine
keywords: Autophagy; Chloramphenicol; Ischemia-reperfusion; Preconditioning; Sevoflurane