Isoprostane release following coronary revascularization in humans

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ABSTRACTS / Journal of Molecular and Cellular Cardiology 42 (2007) S190–S218

Cardiac specific overexpression of COX-2 protects against ischemia/reperfusion injury Javier Inserte2, Belen Molla1 , Victor Hernando2, Paloma Martín-Sanz1, Lisardo Boscá1, Marta Casado1, David GarciaDorado2. 1IBV, Valencia, Spain. 2HUVH. S Cardiologia, Barcelona, Spain Cyclooxygenase (COX)-2 expression in the heart increases after myocardial infarction. Its contribution to reperfusion induced cell death is still a matter of debate. The aim of this study was to analyse the tolerance of a new transgenic murine model overexpressing COX-2 in the heart to reperfusion induced myocardial cell death. Transgenic mice overexpress functional COX-2 (TgCOX-2) specifically in cardiomyocytes under the control of alphamyosin heavy chain promoter as was confirmed by immunoblotting and increased levels of PGE2 myocardium. Histological and echocardiographic analysis of the heart showed no differences in the phenotype with respect to wild type (WT) mice. To test the role of COX-2 in reperfusion injury, hearts from male TgCOX-2 and WT mice were perfused in a langendorff system and subjected to 40 min of global ischemia and 1 h of reperfusion. Reperfused TgCOX-2 hearts significantly improved functional recovery (32.9 ± 6.2% vs. 9.45 ± 4.4%, p = 0.004) and reduced cell death assessed by LDH release (178.9 ± 22.7 U/60 min/gdw vs. 314.6 ± 28.6 U/60 min/ gdw, p < 0.001) and TTC staining (54.7 ± 5.2% vs. 32.1 ± 5.0%, p = 0.002). Pretreatment of mice with the COX-2 inhibitor DFU (10 mg/Kg) before the ischemia/reperfusion protocol resulted in a 42% reduction of myocardial PGE2 levels and attenuated cardioprotection. DFU treatment revealed a significant linear correlation between the level of myocardial PGE2 and the extend of myocardial cell death (r2 = 0.66, p < 0.001). In conclusion, our results demonstrate that COX-2 overexpression has a cardioprotective effect against ischemia/reperfusion induced cell death. Keywords: Ischemia/reperfusion; COX-2; Transgenic mice doi:10.1016/j.yjmcc.2007.03.606

Acute myocardial infarction is a global coronary phenomenon Rami M. Chreih, Dan Deleanu, Irina Modavu, Carmen Ginghina. “Prof. Dr. C.C. Iliescu” Inst. for Cardiovascular Disease - Bucharest, Romania This study aims at appreciating whether myocardial infarction represents a global phenomenon that affects the whole myocardium, also affecting coronary artery flow in non-culprit arteries, rather than a localized one, only affecting coronary flow in culprit arteries. 84 patients that underwent primary PTCA (percutaneous transluminal coronary angioplasty) with stent and 172 patients with normal angiographic coronary arteries were enrolled in the study. The number of

frames necessary for the dye to reach certain standardized landmarks was registered, in order to objectively assess the coronary artery flow as a continuous variable. The statistic data revealed that the quantitative assessment of the coronary flow through CTFC (corrected TIMI frame count) pins up a difference between the flow on non-culprit coronary arteries (24.651 ± 8.381) and the flow on normal angiographic coronary arteries (17.529 ± 3.16) (p < 0.005), the result also being valid for each of the three coronary arteries separately analyzed: LAD (left anterior descending (24.48 ± 7.6 vs. 17.767 ± 3.27) (p < 0.005), Cx (circumflex) (22.574 ± 7.238 vs. 16.96 ± 2.943) (p < 0.005) and RCA (right coronary artery) (27.046 ± 10.211 vs. 17.72 ± 3.235) (p < 0.005). Conclusions: Significant differences regarding the flow on non-culprit coronary arteries in patients that suffered acute myocardial infarction (AMI) and the flow on the coronary arteries of the patients with normal angiographic results might be interpreted as the expression of global myocardial suffering. Keywords: Infarction; Coronary flow doi:10.1016/j.yjmcc.2007.03.607

Isoprostane release following coronary revascularization in humans Kirsti Berg, Heidi Brurok, Sissel Skarra, Rune Haaverstad, Rune Wiseth, Samar Basu, Per Jynge. Dept. of Circ and Med Imag, NTNU, Norway The aim of the present work is to identify oxidative stress during ischemia–reperfusion in humans. In three clinical studies on patients treated with elective PCI (P1, n = 38); primary PCI (P2, n = 16), and elective CABG (P3, n = 20) we have followed levels of 8-iso-PGF2α (a major isoprostane, and a marker of oxidative stress in vivo) and Troponin T in blood samples taken at multiple timepoints before, during and after procedures. 8-iso-PGF2α increased from baseline level (median 62, 30 and 192 pM) in P1, 2 and 3 respectively to 104, 72 and 423 pM after revascularization. In P3 we observed a stepwise rise with elevation after start of surgery and a non-significant further increase after onset of cardiopulmonally bypass (CPB) and after reperfusion. No correlation between 8-iso-PGF2α and Troponin T was found. Baseline levels of plasma 8-iso-PGF2α differ in all groups with lowest level among the patients with acute myocardial infarction (P2), and the highest level among the patients with stable angina recruited for CABG (P3). These patients reflecting the status of treatment with acetylsalicylic acid (ASA) and heparin. Conclusions: Oxidative stress in the form of isoprostane release was observed during all procedures. However, following CABG isoprostane release was related to the surgical trauma rather than to CPB or reperfusion. Oxidative stress is a multifactorial process with complex interactions between pro- and antioxidant factors. Drugs in common use

ABSTRACTS / Journal of Molecular and Cellular Cardiology 42 (2007) S190–S218

like ASA and heparin may reduce isoprostane release in a clinical setting. Keywords: Oxidative stress; Isoprostane; Ischemia/reperfusion doi:10.1016/j.yjmcc.2007.03.608

Novel cardioprotective role of connective tissue growth factor (CTGF) in ischemia/reperfusion J. Gravning, M. Ahmed, V. Martinov, T. Lueder, G. Czibik, T. Edvardsen, G. Valen, H. Attramadal. Inst. Surg. Res. and Dept. Physio. Univ. of Oslo NO Background: Myocardial CCN2/CTGF is robustly induced in heart failure of diverse etiologies, yet its pathophysiologic role remains unresolved. Methods and results: To elucidate the role of myocardial CTGF in ischemia/reperfusion injury, transgenic mice with cardiac-restricted overexpression of CTGF were employed. Cardiac function as assessed by in vivo left ventricular (LV) pressure-volume analysis was unaltered in Tg-CTGF vs. NLC mice. Global analysis of gene expression by DNA microarray revealed activation of endoplasmatic reticulum stress response genes and a genomic switch to increased glucose utilization in Tg-CTGF hearts. This suggests involvement of CTGF in tissue protection. Accordingly, isolated hearts from Tg-CTGF and NLC mice were subjected to 40 min of global ischemia and subsequently 60 min of reperfusion. Infarct size was markedly diminished in Tg-CTGF vs. NLC hearts (13.9 ± 2.5 vs. 50.6 ± 7.9%, p < 0.01) and recovery of LV developed pressure was enhanced. The ischemia/reperfusion injury salvage kinase pathway was activated in Tg-CTGF hearts, evident as increased phosphorylation of Akt/PKB (Ser 473) and GSK-3β (Ser 9) with resulting activation of glycogen synthase. Increased content of glycogen was evident in the Tg-CTGF hearts. Conclusion: CTGF confers cardioprotection by preemptive preconditioning due to reprogramming of gene expression and activation of survival factors against ischemic injury. Keywords: Cardioprotection; Growth factors; Ischemia/reperfusion doi:10.1016/j.yjmcc.2007.03.609

Attenuation of ischemia reperfusion injury in failing hearts by endothelin-a receptor blockade Karola Trescher, Michael Bauer, Wolfgang Dietl, Seth Hallstroem, Ernst Wolner, Bruno Podesser. LBC for Cardiovascular Research, Vienna, A Objective: Ischemia/reperfusion (I/R) injury due to cardioplegic arrest is a problem in patients with reduced LV function. We investigated the effect of chronic versus acute administration of the selective endothelin-A receptor antagonist TBC3214Na during I/R in failing hearts.

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Methods: Male SD rats underwent coronary ligation. 3 days post infarction group 1 (n = 11) was administered TBC-3214Na continuously with their drinking water, group 2 and 3 received placebo. 7 weeks post infarction hearts were evaluated on a blood perfused working heart during 60′ ischemia and 30′ reperfusion. In group 2 (n = 10) TBC-3214Na and in group 3 placebo were added to cardioplegia during ischemia. Data: At similar infarct size postischemic recovery of cardiac output (group1: 91 ± 10%, group2: 86 ± 11% vs. placebo: 52 ± 15%; p < 0,05) and external heart work (group1: 90 ± 10%, group2: 85 ± 13% vs. placebo: 51 ± 17%, p < 0,05) was significantly enhanced in group 1 + 2 while recovery of coronary flow was only improved in group 2 (group2: 121 ± 23% vs. group1: 75 ± 13%, placebo: 64 ± 15%, p < 0,05). In group 2 myocardial oxygen delivery and high energy phosphates were enhanced accompanied by a lower lactate production, and transmission electron microscopy revealed less ultrastructural damage. Conclusion: Ultrastructural and biochemical evaluation indicates an improvement in capillary perfusion only under acute TBC-3214Na administration during ischemia/reperfusion resulting in a better cardiac function post ischemia. Keywords: Ischemia/reperfusion; Heart failure doi:10.1016/j.yjmcc.2007.03.610

Differential cardioprotective effects of cardiac and non-cardiac adenosine during global ischemia and reperfusion Anwar S. Abd-Elfattah, Mai Ding, S. Jamal Mustafa, Magda A. Mansour, Farid R. Nomair. Department of Surgery, Virginia Commonwealth University, Richmond, VA, USA Simultaneous inhibition of adenosine deaminase with 9erythro(2-hydroxy-3nonyl)adenine (EHNA)] and nucleoside transport (es-ENT1) system with p-nitrobenzylmercapto-purine riboside (NBMPR) before ischemia allows diffrentiation between cardiac and non-cardiac adenosine-mediated protection, in vivo. Methods: Hearts of anesthetized dogs (n = 45) were instrumented to measure global function, in vivo. A vehicle solution (Series A) or a vehicle solution containing 100 μM EHNA and 25 μM of NBMPR (Series B) was infused into the CPB before subjecting the hearts to 30 min of normothermic aortic cross clamping (NACC) and 60 min of reperfusion. Animals in Series A and B were divided to receive a single intracoronary infusion of saline (Control group), 100 μM 8-SPT or 10 μM DPCPX immediately following NACC. ATP pool intermediates were determined using HPLC. Results: Adenosine/inosine ration during ischemia was 10folds higher in B groups than in series A groups. At the end of reperfusion, both 8-SPT and DPPX treatments resulted in an equal reduction in LV function regardless of ENA/NBMPR treatment (Series A vs. B).