title: Pyruvate-fortified cardioplegia suppresses oxidative stress and enhances phosphorylation potential of arrested myocardium.
abstract: Cardioplegic arrest for bypass surgery imposes global ischemia on the myocardium, which generates oxyradicals and depletes myocardial high-energy phosphates. The glycolytic metabolite pyruvate, but not its reduced congener lactate, increases phosphorylation potential and detoxifies oxyradicals in ischemic and postischemic myocardium. This study tested the hypothesis that pyruvate mitigates oxidative stress and preserves the energy state in cardioplegically arrested myocardium. In situ swine hearts were arrested for 60 min with a 4:1 mixture of blood and crystalloid cardioplegia solution containing 188 mM glucose alone (control) or with additional 23.8 mM lactate or 23.8 mM pyruvate and then reperfused for 3 min with cardioplegia-free blood. Glutathione (GSH), glutathione disulfide (GSSG), and energy metabolites [phosphocreatine (PCr), creatine (Cr), P(i)] were measured in myocardium, which was snap frozen at 45 min arrest and 3 min reperfusion to determine antioxidant GSH redox state (GSH/GSSG) and PCr phosphorylation potential {[PCr]/([Cr][P(i)])}. Coronary sinus 8-isoprostane indexed oxidative stress. Pyruvate cardioplegia lowered 8-isoprostane release approximately 40% during arrest versus control and lactate cardioplegia. Lactate and pyruvate cardioplegia dampened (P < 0.05 vs. control) the surge of 8-isoprostane release following reperfusion. Pyruvate doubled GSH/GSSG versus lactate cardioplegia during arrest, but GSH/GSSG fell in all three groups after reperfusion. Myocardial [PCr]/([Cr][P(i)]) was maintained in all three groups during arrest. Pyruvate cardioplegia doubled [PCr]/([Cr][P(i)]) versus control and lactate cardioplegia after reperfusion. Pyruvate cardioplegia mitigates oxidative stress during cardioplegic arrest and enhances myocardial energy state on reperfusion.
authors.affiliation: Department of Integrative Physiology, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107-2699, USA.
authors.forename: E Marty
authors.initials: EM
authors.lastname: Knott
authors.forename: Myoung-Gwi
authors.initials: MG
authors.lastname: Ryou
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.forename: Abraham
authors.initials: A
authors.lastname: Heymann
authors.forename: Arti B
authors.initials: AB
authors.lastname: Sharma
authors.forename: Yu
authors.initials: Y
authors.lastname: Lei
authors.forename: Mirza
authors.initials: M
authors.lastname: Baig
authors.forename: Robert T
authors.initials: RT
authors.lastname: Mallet
authors.forename: Albert H
authors.initials: AH
authors.lastname: Olivencia-Yurvati
mesh_terms: D000136:Acid-Base Equilibrium; D000818:Animals; D002314:Cardioplegic Solutions / Q000494:pharmacology*; D015237:Dinoprost / Q000031:analogs & derivatives / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects; D005260:Female; D005947:Glucose / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D019803:Glutathione Disulfide / Q000378:metabolism; D006324:Heart Arrest, Induced / Q000379:methods*; D006400:Hematocrit; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy* / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D010766:Phosphorylation; D019289:Pyruvic Acid / Q000494:pharmacology*; D034421:Sus scrofa
chemical_list: D002314:Cardioplegic Solutions; C075750:8-epi-prostaglandin F2alpha; D019289:Pyruvic Acid; D015237:Dinoprost; D005978:Glutathione; D005947:Glucose; D019803:Glutathione Disulfide