Myocardial preconditioning against ischemia-reperfusion injury is abolished in Zucker obese rats with insulin resistance

2007 ◽  
Vol 292 (2) ◽  
pp. R920-R926 ◽  
Author(s):  
Prasad V. G. Katakam ◽  
James E. Jordan ◽  
James A. Snipes ◽  
Christina D. Tulbert ◽  
Allison W. Miller ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Manganese Superoxide Dismutase ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Mitochondrial Protein ◽  
Cardiac Injury ◽  
Mitochondrial Oxidative Stress ◽  
Isolated Mitochondria

Insulin resistance (IR) precedes the onset of Type 2 diabetes, but its impact on preconditioning against myocardial ischemia-reperfusion injury is unexplored. We examined the effects of diazoxide and ischemic preconditioning (IPC; 5-min ischemia and 5-min reperfusion) on ischemia (30 min)-reperfusion (240 min) injury in young IR Zucker obese (ZO) and lean (ZL) rats. ZO hearts developed larger infarcts than ZL hearts (infarct size: 57.3 ± 3% in ZO vs. 39.2 ± 3.2% in ZL; P < 0.05) and also failed to respond to cardioprotection by IPC or diazoxide (47.2 ± 4.3% and 52.5 ± 5.8%, respectively; P = not significant). In contrast, IPC and diazoxide treatment reduced the infarct size in ZL hearts (12.7 ± 2% and 16.3 ± 6.7%, respectively; P < 0.05). The mitochondrial ATP-activated potassium channel (KATP) antagonist 5-hydroxydecanoic acid inhibited IPC and diazoxide-induced preconditioning in ZL hearts, whereas it had no effect on ZO hearts. Diazoxide elicited reduced depolarization of isolated mitochondria from ZO hearts compared with ZL (73 ± 9% in ZL vs. 39 ± 9% in ZO; P < 0.05). Diazoxide also failed to enhance superoxide generation in isolated mitochondria from ZO compared with ZL hearts. Electron micrographs of ZO hearts revealed a decreased number of mitochondria accompanied by swelling, disorganized cristae, and vacuolation. Immunoblots of mitochondrial protein showed a modest increase in manganese superoxide dismutase in ZO hearts. Thus obesity accompanied by IR is associated with the inability to precondition against ischemic cardiac injury, which is mediated by enhanced mitochondrial oxidative stress and impaired activation of mitochondrial KATP.

scholarly journals Transient Receptor Potential Ankyrin 1 Activation within the Cardiac Myocyte Limits Ischemia–reperfusion Injury in Rodents

2016 ◽  
Vol 125 (6) ◽  
pp. 1171-1180 ◽  
Author(s):  
Yao Lu ◽  
Honit Piplani ◽  
Stacy L. McAllister ◽  
Carl M. Hurt ◽  
Eric R. Gross
Keyword(s):  
Infarct Size ◽  
Reperfusion Injury ◽  
Cardiac Myocytes ◽  
Cardiac Myocyte ◽  
Transient Receptor Potential ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Cardiac Injury ◽  
In Vivo Model

Abstract Background Recent evidence suggests that cross talk exists between cellular pathways important for pain signaling and ischemia–reperfusion injury. Here, the authors address whether the transient receptor potential ankyrin 1 (TRPA1) channel, important in pain signaling, is present in cardiac myocytes and regulates cardiac ischemia–reperfusion injury. Methods For biochemical analysis of TRPA1, techniques including quantitative polymerase chain reaction, Western blot, and immunofluorescence were used. To determine how TRPA1 mediates cellular injury, the authors used an in vivo model of rat cardiac ischemia–reperfusion injury and adult rat–isolated cardiac myocytes subjected to hypoxia–reoxygenation. Results The authors’ biochemical analysis indicates that TRPA1 is within the cardiac myocytes. Further, using a rat in vivo model of cardiac injury, the TRPA1 activators ASP 7663 and optovin reduce myocardial injury (45 ± 5%* and 44 ± 8%,* respectively, vs. control, 66 ± 6% infarct size/area at risk; n = 6 per group; mean ± SD; *P &lt; 0.001). TRPA1 inhibition also blocked the infarct size–sparing effects of morphine. In isolated cardiac myocytes, the TRPA1 activators ASP 7663 and optovin reduce cardiac myocyte cell death when given during reoxygenation (20 ± 3%* and 22 ± 4%* vs. 36 ± 3%; percentage of dead cells per field, n = 6 per group; mean ± SD; *P &lt; 0.05). For a rat in vivo model of cardiac injury, the infarct size–sparing effect of TRPA1 activators also occurs during reperfusion. Conclusions The authors’ data suggest that TRPA1 is present within the cardiac myocytes and is important in regulating myocardial reperfusion injury. The presence of TRPA1 within the cardiac myocytes may potentially explain why certain pain relievers that can block TRPA1 activation, such as cyclooxygenase-2 inhibitors or some nonsteroidal antiinflammatory drugs, could be associated with cardiovascular risk.

Abstract 115: Post-ischemic Estrogen Administration Protects the Myocardium Against Ischemia/Reperfusion Injury by Reducing Mitochondrial Protein Ubiquitination, Acetylation and Calpain10 Levels and Inhibition of the mPTP Opening via GPER1 Activation

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Yansheng Feng ◽  
Ngonidzashe Benson Madungwe ◽  
Mohammad Enamul Kabir ◽  
Jean C. Bopassa
Keyword(s):  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Mitochondrial Protein ◽  
Myocardial Infarct Size ◽  
Protein Acetylation ◽  
Protein Ubiquitination ◽  
Mptp Opening

Introduction: We recently found in isolated perfused hearts that acute pre-ischemic estrogen-induced cardioprotection against ischemia/reperfusion injury is mainly mediated via G protein-coupled estrogen receptor1 (GPER1) activation but not through classical estrogen receptors: alpha (ERα) and beta (ERβ). Hypothesis: We investigated whether acute post-ischemic estrogen (PI-E2) treatment can also induce cardioprotective effects via GPER1 activation in the intact animal subjected to ischemia/reperfusion injury. Methods: Male and ovariectomized female Sprague-Dawley rats were anesthetized with ketamine (80 mg/kg i.p.) and xylazine (8 mg/kg i.p.). Hearts were subjected to 35 min of the left anterior descending (LAD) artery occlusion, followed by 180 min reperfusion. An E2 bolus (50 mg/kg body weight) or PBS (same volume) was applied via the femoral vein 5 min before reperfusion and a GPER1 antagonist, G15, was given 10 min before E2. Area at risk (AAR) was identified using Evans Blue dye and myocardial infarct size assessed by TTC staining method. Mitochondria calcium retention capacity (CRC) required to induce mitochondrial permeability transition pore (mPTP) opening was assessed after 10 min reperfusion. Expression of ubiquitinated, acetylated, as well as calpains 1 and 10 proteins was measured by Western Blot in mitochondrial and cytosolic fractions. Results: We found that PI-E2 treatment reduced myocardial infarct size normalized to the AAR or the whole LV and improved mitochondrial CRC. PI-E2 treatment reduced mitochondrial protein acetylation, ubiquitination, and decreased calpain10 levels in mitochondrial but not in cytosolic fractions as compared to control, respectively. Interestingly, all these effects of E2 were abolished by addition of G15. Conclusion: Acute post-ischemic GPER1 activation by E2 induces cardioprotection against ischemia/reperfusion injury. PI-E2 effects through GPER1 involve the reduction of the levels of mitochondrial protein acetylation, ubiquitination, and calpain10. These PI-E2-GPER1 effects lead to inhibition of the mPTP opening.

Abstract 442: Intralipid Protects the Heart in Late Pregnancy Against Ischemia/Reperfusion Injury by Reducing Cardiomyocyte Apoptosis via Mir122 Induction

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Jingyuan Li ◽  
Negar Motayagheni ◽  
Neusha Barakati ◽  
Mansoureh Eghbali
Keyword(s):  
Coronary Artery ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Microarray Analysis ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Late Pregnancy ◽  
Control Group ◽  
Myocardial Infarct Size ◽  
Microrna Microarray

The prevalence of coronary artery disease in late pregnancy (LP) has increased recently due to significant changes in women’s lifestyle patterns (age, stress, smoking, diabetes and chronic hypertension). Myocardial infarction during LP and the peripartum is associated with significant maternal mortality and morbidity compared to non pregnant women for unclear reasons. We have recently demonstrated that cardiac vulnerability to I/R injury drastically increases in LP rodents, leading to myocardial infarct size ~4 fold greater than in non-pregnant controls. We also discovered that administration of intralipid (an emulsion of soy bean oil, egg yolk phospholipids and glycerol) at reperfusion resulted in ~60% reduction in infarct size of the heart in LP rat subjected to I/R injury. However, the molecular mechanisms underlying intralipid-induced cardioprotection in late pregnancy is not clear. Here we hypothesized that intralipid protects the heart in late pregnancy by regulating the levels of specific microRNAs. The left anterior descending coronary artery was occluded in LP rats (21-22 days of pregnancy) for 45 min followed by 3 hr of reperfusion. One single bolus of PBS (control group) or 20% intralipid (intralipid group) was applied through the femoral vein 5 min before the reperfusion. The hearts of control and intralipid groups were used for microRNA microarray analysis (Ocean Ridge Biosciences). MicroRNA-microarray analysis identified MiR122 as a novel micro-RNA which its expression was strikingly upregulated more than 10 fold in the heart of LP rats in intralipid group compared to control group. miR122 regulates apoptosis in cardiomyocytes subjected to hypoxia/reoxygenation since miR122-overexpression resulted in reduced apoptosis, whereas knockdown of miR122 enhanced apoptosis. Pyruvate kinase isoform M2 (PKM2), which is known to regulate cell apoptosis in the liver, is a direct target of miR122. Our data show that PKM2 and caspase 3 are two targets of miR122 since the expression of PKM2 and capase-3 in the heats subjected to I/R was significantly lower in intralipid group compared to control group in LP. In conclusion intralipid protects the heart in late pregnancy against ischemia/reperfusion injury via inducing miR122 by targeting PKM2.

Abstract 16598: The Role of Paraoxonase 2 in Myocardial Ischemia/Reperfusion Injury

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Jingyuan Li ◽  
Victor R Grijalva ◽  
Srinivasa T Reddy ◽  
Mansoureh Eghbali
Keyword(s):  
Myocardial Ischemia ◽  
Infarct Size ◽  
Er Stress ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ros Production ◽  
Myocardial Ischemia Reperfusion Injury ◽  
Myocardial Ischemia Reperfusion

Objectives: Paraoxonases (PON) gene family consists of three proteins PON1, PON2, and PON3. PON2 is an intracellular membrane-associated protein that is widely expressed in vascular cells and many tissues. At the subcellular level, PON2 is localized to both the ER and mitochondria, and protects against oxidative stress. Hypothesis: The aim of this study was to investigate the role of PON2 in myocardial ischemia reperfusion injury. Methods: PON2 deficient (PON2-/-) and WT male mice were subjected to in-vivo ischemia/reperfusion injury. The left anterior descending coronary artery was occluded for 30 min followed by 24 hr of reperfusion. The infarct size, mitochondrial calcium retention capacity (CRC) and reactive oxygen species (ROS) generation were measured. The expression of C/EBP homologous protein (CHOP), GSK3b and phosphate GSK3b protein were examined by Western Blot. The number of animals was 5-7/group and data were expressed as mean±SEM. T test were used for statistical analysis. Probability values <0.05 were considered statistically significant. Results: The infarct size was ~2 fold larger in PON2 deficient mice compared to WT mice (p<0.05). The threshold for opening of mitochondrial permeability transition pore (mPTP) in response to calcium overload was much lower in PON2-/- mice compared with WT mice (173±19 in PON2-/-, 250±41 in WT, nmol/mg-mitochondrial protein, p<0.05). The ROS production was ~2 fold higher in isolated cardiac mitochondria from PON2-/- mice compared with WT mice (p<0.05). ER stress protein CHOP increased significantly in PON2-/- mice compared to WT mice (normalized to WT: 1±0.05 in WT, 1.66±0.08 in PON2-/-, p<0.001). Phospho-GSK3b level was significantly downregulated in in PON2-/- mice compared to WT mice (pGSK3b/GSK3b normalized to WT: 1±0.06 in WT 0.67±0.08 in PON2-/-, p<0.05). Conclusions: PON2 regulates myocardial ischemia/reperfusion injury via inhibiting the opening of mPTP, which is associated with reduced mitochondria ROS production, deactivation of ER stress signaling CHOP and GSK3b.

scholarly journals Heat Shock Protein 72 Enhances Manganese Superoxide Dismutase Activity During Myocardial Ischemia-Reperfusion Injury, Associated With Mitochondrial Protection and Apoptosis Reduction

Circulation ◽  
2002 ◽  
Vol 106 (12_suppl_1) ◽  
Author(s):  
Ken Suzuki ◽  
Bari Murtuza ◽  
Ivan A. Sammut ◽  
Najma Latif ◽  
Jay Jayakumar ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Reperfusion Injury ◽  
Manganese Superoxide Dismutase ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Heat Shock Protein 72 ◽  
Manganese Superoxide

Background Heat shock protein 72 (HSP72) is known to provide myocardial protection against ischemia-reperfusion injury by its chaperoning function. Target molecules of this effect are presumed to include not only structural proteins but also other self-preservation proteins. The details, however, remain unknown. Manganese superoxide dismutase (Mn-SOD) is an enzyme that preserves mitochondria, a key organelle for cellular respiration, from reperfusion injury and limits mitochondria-related apoptosis. We hypothesized that Mn-SOD would play a role in HSP72-mediated cardioprotection. Methods and Results Rat hearts were transfected with human HSP72 by intra-coronary infusion of Hemagglutinating Virus of Japan-liposome, resulting in global myocardial overexpression of HSP72. After ischemia-reperfusion injury, cardiac function (left ventricular systolic pressure, maximum dP/dt, minimum dP/dt, and coronary flow) was improved in the HSP72-transfected hearts compared with control-transfected ones, corresponding with less leakage of creatine kinase and mitochondrial aspartate aminotransferase. Postischemic Mn-SOD content and activity in the HSP72-transfected hearts were enhanced in comparison with the controls (content: 96.9±4.1 versus 85.5±2.5% to the preischemic level, P =0.038; activity: 93.9±2.2 versus 82.2±3.7%, P =0.022), associated with improved mitochondrial respiratory function (postischemic percent respiratory control index; NAD + -linked: 81.3±3.8 versus 18.5±4.4%; FAD-linked: 71.8±5.5 versus 20.7±5.3%, P <0.001). In addition, incidence of postischemic cardiomyocyte apoptosis was attenuated in the HSP72-transfected hearts (4.0±1.1 versus 10.3±3.3%, P =0.036), correlating with an increased Bcl-2 level and reduced up-regulation of caspase-3. Conclusions These data suggest that the enhanced Mn-SOD activity during ischemia-reperfusion injury, which is associated with mitochondrial protection and apoptosis reduction, is a possible mechanism of HSP72-induced cardioprotection.

Blocking Na+/H+ exchange reduces [Na+]i and [Ca2+]i load after ischemia and improves function in intact hearts

2001 ◽  
Vol 281 (6) ◽  
pp. H2398-H2409 ◽  
Author(s):  
Jianzhong An ◽  
Srinivasan G. Varadarajan ◽  
Amadou Camara ◽  
Qun Chen ◽  
Enis Novalija ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Infarct Size ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ringer Solution ◽  
Left Ventricular ◽  
Isolated Hearts ◽  
Intracellular Ca ◽  
Ionic Basis

We determined in intact hearts whether inhibition of Na+/H+ exchange (NHE) decreases intracellular Na+ and Ca2+ during ischemia and reperfusion, improves function during reperfusion, and reduces infarct size. Guinea pig isolated hearts were perfused with Krebs-Ringer solution at 37°C. Left ventricular (LV) free wall intracellular Na+ concentration ([Na+]i) and intracellular Ca2+ concentration ([Ca2+]i) were measured using fluorescence dyes. Hearts were exposed to 30 min of ischemia with or without 10 μM of benzamide (BIIB-513), a selective NHE-1 inhibitor, infused for 10 min just before ischemia or for 10 min immediately on reperfusion. At 2 min of reperfusion, BIIB-513 given before ischemia decreased peak increases in [Na+]i and [Ca2+]i, respectively, from 2.5 and 2.3 times (controls) to 1.6 and 1.3 times preischemia values. At 30 min of reperfusion, BIIB-513 increased systolic-diastolic LV pressure (LVP) from 49 ± 2% (controls) to 80 ± 2% of preischemia values. BIIB-513 reduced ventricular fibrillation by 54% and reduced infarct size from 64 ± 1% to 20 ± 3%. First derivative of the LVP, O2 consumption, and cardiac efficiency were also improved by BIIB-513. Similar results were obtained with BIIB-513 given on reperfusion. These data show that Na+ loading is a marker of reperfusion injury in intact hearts in that inhibiting NHE reduces Na+ and Ca2+ loading during reperfusion while improving function. These results clearly implicate the ionic basis by which inhibiting NHE protects the guinea pig intact heart from ischemia-reperfusion injury.

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