fr-167653 and Myocardial-Ischemia

Coronary artery occlusion increased the TNF alpha level in the membrane fraction of the rat heart, almost maximally at 30 min. TNF alpha immunofluorescence labeled streak-like reticular structures inside of the cardiomyocyte but not vascular or interstitial cells in myocardial ischemia. Immuno-electron microscopy confirmed the localization of TNF alpha between myofibrils, mitochondria, or other membrane structures in the ischemic cardiomyocyte. Ischemic preconditioning (IP) is the protection of myocardium conferred by cycles of brief ischemia-reperfusion. The increases in TNF alpha production, as well as phosphorylation of p38 MAP kinase and S6 kinase after ischemia were inhibited by IP or p38 MAP kinase inhibitors (SB203580, FR167653). TNF alpha production appeared to be regulated possibly at the post-transcriptional step by ribosomal S6 phosphorylation given that IP did not suppress TNF alpha mRNA up-regulation and was independent of NFkappaB activation. Electron microscopy (EM) showed mitochondria damage in ischemic cardiomyocyte, which was inhibited either by IP or SB203580. This is the first demonstration of the TNF alpha up-regulation in membrane structures of ischemic cardiomyocyte through p38 MAP kinase-mediated post-transcriptional mechanism, in association with mitochondrial damage.

Topics: Animals; Enzyme Inhibitors; Imidazoles; Ischemic Preconditioning, Myocardial; Male; Mitochondria, Heart; Myocardial Ischemia; Myocardium; Myocytes, Cardiac; p38 Mitogen-Activated Protein Kinases; Pyrazoles; Pyridines; Rats; Rats, Sprague-Dawley; RNA, Messenger; Tumor Necrosis Factor-alpha; Up-Regulation

The activation of p38 mitogen-activated protein kinase (MAPK) plays an important role in ischemia-reperfusion injury. This study evaluated the effects of p38 MAPK inhibition using FR167653, a novel p38 MAPK inhibitor, as an additive to Celsior solution in canine heart transplantation from non-heart-beating donors (NHBDs).. Donor hearts were left in situ for 20 minutes after cardiac arrest, which was induced by rapid exsanguination. Twelve donor-recipient pairs of mongrel dogs were divided into two groups: the control and FR167653 (FR) groups (n=6 each). In both groups, the grafts were subjected to coronary flushing and immersed in Celsior solution for 4 hours with or without FR167653. Orthotopic heart transplantation was then performed. Cardiac output (CO), left ventricular pressure (LVP), and end-systolic maximal elastance (Emax) were measured 2 hours after weaning from cardiopulmonary bypass (CPB), and the hearts were then harvested for histopathologic study. The activation of p38 MAPK was evaluated in another 20 mongrel dogs.. In the FR group, CO, LVP recovery rate, and Emax were significantly (P<0.05) higher 2 hours after weaning from CPB, histopathologic damage was attenuated, and the activation of p38 MAPK was significantly (P<0.05) inhibited 10 minutes after reperfusion compared with the control group.. The addition of FR167653 to Celsior solution improved heart-graft viability, probably by way of the inhibition of p38 MAPK activation, which may attenuate ischemia-reperfusion injury in heart transplantation from NHBDs.

Topics: Animals; Cardioplegic Solutions; Disaccharides; Dogs; Electrolytes; Enzyme Activation; Enzyme Inhibitors; Glutamates; Glutathione; Growth Inhibitors; Heart; Heart Arrest; Heart Transplantation; Histidine; Mannitol; Mitogen-Activated Protein Kinases; Models, Animal; Myocardial Ischemia; Myocardium; p38 Mitogen-Activated Protein Kinases; Pyrazoles; Pyridines; Reperfusion Injury

FR167653 inhibits the production of inflammatory cytokines such as interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) in human monocytes in a dose-dependent manner. We examined the effects of FR167653 on the propagation of myocardial infarction resulting from coronary occlusion-reperfusion and the time course of expression of these cytokines in myocardial tissue in rats. Myocardial infarction was induced by coronary ligation for 20 minutes followed by 2 hours of reperfusion. Although hemodynamic parameters did not differ significantly during coronary occlusion-reperfusion, the size of the infarct was significantly reduced by intravenous administration of FR167653 before occlusion (p < 0.01). mRNA levels of IL-1beta and TNF-alpha assessed by the reverse-transcriptase polymerase chain reaction method were significantly increased during coronary occlusion-reperfusion in the ischemic myocardium. Treatment with FR167653, however, significantly reduced the increased expression of these cytokines. These results indicate that the expression of inflammatory cytokines increases in the ischemic-reperfused myocardium and that the inhibition of the increased expression of cytokines by FR167653 effectively reduces myocardial ischemia-reperfusion injury.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Dose-Response Relationship, Drug; Hemodynamics; Immunosuppressive Agents; Interleukin-1; Male; Myocardial Ischemia; Polymerase Chain Reaction; Pyrazoles; Pyridines; Rats; Rats, Wistar; Reperfusion Injury; Reverse Transcriptase Polymerase Chain Reaction; Time Factors