Changes in mitochondrial properties may contribute to enhanced resistance to ischemia–reperfusion injury in the diabetic rat heart

2017 ◽  
Vol 95 (8) ◽  
pp. 969-976 ◽  
Author(s):  
Martina Muráriková ◽  
Miroslav Ferko ◽  
Iveta Waczulíková ◽  
Magdaléna Jašová ◽  
Ivana Kancirová ◽  
...  
Keyword(s):  
Membrane Fluidity ◽  
Manganese Superoxide Dismutase ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Complete Recovery ◽  
Left Ventricular ◽  
Functional Restoration ◽  
Diabetic Rat ◽  
Protein Levels ◽  
Male Wistar Rats

Diabetes mellitus, besides having deleterious effects, induces cardiac adaptation that may reduce the heart’s susceptibility to ischemia–reperfusion (IR) injury. This study aimed to investigate whether changes in mitochondrial properties are involved in the mechanisms of increased resistance of the diabetic heart to IR. Adult male Wistar rats were made diabetic by a single dose of streptozotocin (65 mg·kg–1, i.p.), and on the day 8, Langendorff-perfused hearts were subjected to 30 min global ischemia and 40 min reperfusion. Baseline preischemic parameters in the diabetic hearts did not differ markedly from those in the nondiabetic controls, except for lower left ventricular developed pressure, higher mitochondrial membrane fluidity, and protein levels of manganese superoxide dismutase. On the other hand, diabetic hearts showed significantly better post-IR functional restoration and reduced arrhythmogenesis associated with lower reactive oxygen species production as compared with healthy controls. IR decreased membrane fluidity in both experimental groups; however, it led to a complete recovery of mitochondrial Mg2+-ATPase activity in diabetics in contrast to its reduction in nondiabetics. These findings indicate that the heart may become adapted to diabetes-induced alterations that might increase its tolerance to an ischemic insult. Preserved mitochondrial function might play a role in the mechanisms of the heart’s resistance to IR injury in diabetics.

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.

Differential temporal inhibition of mitochondrial fission by Mdivi-1 exerts effective cardioprotection in cardiac ischemia/reperfusion injury

2018 ◽  
Vol 132 (15) ◽  
pp. 1669-1683 ◽  
Author(s):  
Chayodom Maneechote ◽  
Siripong Palee ◽  
Sasiwan Kerdphoo ◽  
Thidarat Jaiwongkam ◽  
Siriporn C. Chattipakorn ◽  
...  
Keyword(s):  
Infarct Size ◽  
Mitochondrial Function ◽  
Ischemia Reperfusion Injury ◽  
Mitochondrial Dynamics ◽  
Ischemia Reperfusion ◽  
Mitochondrial Fission ◽  
Left Ventricular ◽  
Lv Function ◽  
Male Wistar Rats ◽  
Group A

Altered cardiac mitochondrial dynamics with excessive fission is a predominant cause of cardiac dysfunction during ischemia/reperfusion (I/R) injury. Although pre-ischemic inhibition of mitochondrial fission has been shown to improve cardiac function in I/R injury, the effects of this inhibitor given at different time-points during cardiac I/R injury are unknown. Fifty male Wistar rats were subjected to sham and cardiac I/R injury. For cardiac I/R injury, rats were randomly divided into pre-ischemia, during-ischemia, and upon onset of reperfusion group. A mitochondrial fission inhibitor, Mdivi-1 (mitochondrial division inhibitor 1) (1.2 mg/kg) was used. During I/R protocols, the left ventricular (LV) function, arrhythmia score, and mortality rate were determined. Then, the heart was removed to determine infarct size, mitochondrial function, mitochondrial dynamics, and apoptosis. Our results showed that Mdivi-1 given prior to ischemia, exerted the highest level of cardioprotection quantitated through the attenuated incidence of arrhythmia, reduced infarct size, improved cardiac mitochondrial function and fragmentation, and decreased cardiac apoptosis, leading to preserved LV function during I/R injury. Mdivi-1 administered during ischemia and upon the onset of reperfusion also improved cardiac mitochondrial function and LV function, but at a lower efficacy than when it was given prior to ischemia. Taken together, mitochondrial fission inhibition after myocardial ischemic insults still exerts cardioprotection by attenuating mitochondrial dysfunction and dynamic imbalance, leading to decreased infarct size and ultimately improved LV function after acute cardiac I/R injury in rats. These findings indicate its potential clinical usefulness.

scholarly journals Preconditioning protects the heart in a prolonged uremic condition

2012 ◽  
Vol 303 (10) ◽  
pp. H1229-H1236 ◽  
Author(s):  
Gabriella F. Kocsis ◽  
Márta Sárközy ◽  
Péter Bencsik ◽  
Márton Pipicz ◽  
Zoltán V. Varga ◽  
...  
Keyword(s):  
Infarct Size ◽  
Ischemic Preconditioning ◽  
Metabolic Diseases ◽  
Ischemia Reperfusion Injury ◽  
Myocardial Dysfunction ◽  
Ischemia Reperfusion ◽  
Cardioprotective Effect ◽  
Area At Risk ◽  
Protein Levels ◽  
Male Wistar Rats

Metabolic diseases such as hyperlipidemia and diabetes attenuate the cardioprotective effect of ischemic preconditioning. In the present study, we examined whether another metabolic disease, prolonged uremia, affects ischemia/reperfusion injury and cardioprotection by ischemic preconditioning. Uremia was induced by partial nephrectomy in male Wistar rats. The development of uremia was verified 29 wk after surgery. Transthoracic echocardiography was performed to monitor cardiac function. At week 30, hearts of nephrectomized and sham-operated rats were isolated and subjected to a 30-min coronary occlusion followed by 120 min reperfusion with or without preceding preconditioning induced by three intermittent cycles of brief ischemia and reperfusion. In nephrectomized rats, plasma uric acid, carbamide, and creatinine as well as urine protein levels were increased as compared with sham-operated controls. Systolic anterior and septal wall thicknesses were increased in nephrectomized rats, suggesting the development of a minimal cardiac hypertrophy. Ejection fraction was decreased and isovolumic relaxation time was shortened in nephrectomized rats demonstrating a mild systolic and diastolic dysfunction. Infarct size was not affected significantly by nephrectomy itself. Ischemic preconditioning significantly decreased infarct size from 24.8 ± 5.2% to 6.6 ± 1.3% in the sham-operated group and also in the uremic group from 35.4 ± 9.5% to 11.9 ± 3.1% of the area at risk. Plasma ANG II and nitrotyrosine were significantly increased in the uremic rats. We conclude that although prolonged experimental uremia leads to severe metabolic changes and the development of a mild myocardial dysfunction, the cardioprotective effect of ischemic preconditioning is still preserved.

Depressed tolerance to fluorocarbon-simulated ischemia in failing myocardium due to impaired [Ca2+]imodulation

2000 ◽  
Vol 278 (5) ◽  
pp. H1446-H1456 ◽  
Author(s):  
Jiang-Yong Min ◽  
Thomas G. Hampton ◽  
Ju-Feng Wang ◽  
Joseph DeAngelis ◽  
James P. Morgan
Keyword(s):  
Mechanical Performance ◽  
Ischemia Reperfusion Injury ◽  
Isometric Force ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Physiological Salt Solution ◽  
Simulated Ischemia ◽  
Severe Impairment ◽  
Intracellular Ca ◽  
Male Wistar Rats

The aim of this study was to investigate the tolerance of failing myocardium from postinfarction rats to simulated ischemia. Myocardial infarction (MI) was induced by ligation of the left coronary artery in male Wistar rats. Isometric force and free intracellular Ca2+ concentration ([Ca2+]i) were measured in isolated left ventricular papillary muscles from sham-operated and post-MI animals 6 wk after surgery. Ischemia was simulated by using fluorocarbon immersion with hypoxia. Results showed that mechanical performance was depressed during the period of hypoxia in physiological salt solution (44 ± 7% of baseline in sham vs. 30 ± 6% of baseline in MI, P < 0.05) or ischemia (16 ± 2% of baseline in sham vs. 9 ± 1% of baseline in MI, P< 0.01) accompanied by no corresponding decrease of peak [Ca2+]i (hypoxia: 51 ± 8% of baseline in sham vs. 46 ± 7% of baseline in MI, P = NS; ischemia: 47 ± 5% of baseline in sham, 39 ± 7% of baseline in MI, P = NS). After reoxygenation, [Ca2+]i rapidly returned to near preischemic basal levels, whereas developed tension in fluorocarbon remained significantly lower. This dissociation between peak [Ca2+]i and isometric contractility was more pronounced in the failing myocardium from postinfarction rats. In conclusion, more severe impairment of [Ca2+]i homeostasis in the failing myocardium from postinfarction rats increases susceptibility to ischemia-reperfusion injury.

scholarly journals AMPK/mTOR-mediated therapeutic effect of metformin on myocardial ischemia reperfusion injury in diabetic rat

2020 ◽  
Author(s):  
Lei Zhang ◽  
Xiaochun Zhang ◽  
Lihua Guan ◽  
Daxin Zhou ◽  
Junbo Ge
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Negative Control ◽  
Signalling Pathways ◽  
Diabetic Rat ◽  
Myocardial Infarct Size ◽  
Protein Levels ◽  
Myocardial Ischemia Reperfusion

Abstract BACKGROUND: The autophagy associated signalling pathways such as AMPK/mTOR previously were suggested to play a crucial role in protecting from ischemia-reperfusion injury (IRI). The objective of this study was to evaluate the effect of metformin (DMBG) on autophagy during myocardial IRI with diabetes mellitus (DM). METHODS: The DM rat model was established using streptozocin, and further induced ischemia model via transitory ligation of the left anterior coronary artery and following reperfusion. The model rats were treated with 400 mg/kg/day DMBG for one week. Autophagosomes were investigated using transmission electron microscopy. Autophagy-associated signalling pathways were detected by western blot. RESULTS: The myocardial infarct size was shown to significantly increase in the DM rats exposed to IRI compared to negative control, but decrease in DMBG treated. The mature autophagosomes were elevated in infarction and marginal zones of DM+IRI+DMBG compared to DM+IRI. Furthermore, the increasing protein levels of LC3-II, BECLIN 1, autophagy related 5 (ATG5) and AMP-activated protein kinase suggested activated autophagy-associated intracellular signalling AMPK and mTOR pathways upon DMBG treated. CONCLUSIONS: Taken together, the outcomes demonstrated that DMBG could activate autophagy process to provide a cardio-protective effect against DM induced myocardial IRI.

The role of coronary flow and adenosine in postischemic recovery of septic rat hearts

1998 ◽  
Vol 275 (1) ◽  
pp. H8-H14 ◽  
Author(s):  
Jitka A. Ismail ◽  
Kathleen H. McDonough
Keyword(s):  
Coronary Flow ◽  
Myocardial Function ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Complete Recovery ◽  
Left Ventricular ◽  
Endogenous Adenosine ◽  
Rat Hearts ◽  
Adenosine Antagonism ◽  
Postischemic Recovery

Sepsis depresses myocardial function but prevents subsequent ischemia-reperfusion injury. Elevated coronary flow (CF) and endogenous adenosine may be important factors in the complete recovery of postischemic myocardial function observed in septic rat hearts. The purpose of this study was to determine the effects of manipulating CF and of antagonizing adenosine receptors on the postischemic recovery of left ventricular developed pressure (LVDP) in septic and control rat hearts. The relationship between CF and LVDP in septic rat hearts before ischemia was depressed compared with control. However, this relationship was unaltered by ischemia in septic hearts, whereas in control hearts it was severely depressed. Preventing the elevation of CF during reperfusion did not significantly affect the recovery of LVDP in septic rat hearts. Adenosine antagonism by 8-phenyltheophylline (0.1 and 1 nM) prevented the elevated CF during reperfusion, and the higher dose significantly depressed postischemic function. We conclude that elevated CF did not contribute to the recovery of postischemic LVDP in septic rat hearts but that endogenous adenosine may provide protection from ischemia.

scholarly journals Involvement of PKCε in Cardioprotection Induced by Adaptation to Chronic Continuous Hypoxia

2015 ◽  
pp. 191-201 ◽  
Author(s):  
K. HOLZEROVÁ ◽  
M. HLAVÁČKOVÁ ◽  
J. ŽURMANOVÁ ◽  
G. BORCHERT ◽  
J. NECKÁŘ ◽  
...  
Keyword(s):  
Cell Viability ◽  
Ventricular Myocytes ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Acute Ischemia ◽  
Mrna Levels ◽  
Inhibitory Peptide ◽  
Male Wistar Rats ◽  
Ldh Release

Continuous normobaric hypoxia (CNH) renders the heart more tolerant to acute ischemia/reperfusion injury. Protein kinase C (PKC) is an important component of the protective signaling pathway, but the contribution of individual PKC isoforms under different hypoxic conditions is poorly understood. The aim of this study was to analyze the expression of PKCε after the adaptation to CNH and to clarify its role in increased cardiac ischemic tolerance with the use of PKCε inhibitory peptide KP-1633. Adult male Wistar rats were exposed to CNH (10 % O2, 3 weeks) or kept under normoxic conditions. The protein level of PKCε and its phosphorylated form was analyzed by Western blot in homogenate, cytosolic and particulate fractions; the expression of PKCε mRNA was measured by RT-PCR. The effect of KP-1633 on cell viability and lactate dehydrogenase (LDH) release was analyzed after 25-min metabolic inhibition followed by 30-min re-energization in freshly isolated left ventricular myocytes. Adaptation to CNH increased myocardial PKCε at protein and mRNA levels. The application of KP-1633 blunted the hypoxia-induced salutary effects on cell viability and LDH release, while control peptide KP-1723 had no effect. This study indicates that PKCε is involved in the cardioprotective mechanism induced by CNH.

Abstract 183: Improved Ca-cycling by Dexamethasone Preserves Contractility After Ischemia/Reperfusion in Diabetic Rat Cardiomyocytes

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Christian Schach ◽  
Michael Goetz ◽  
Hendrik Busse ◽  
York Zausig ◽  
Marzena Drymalski ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Heart Function ◽  
Ischemia Reperfusion ◽  
Cellular Level ◽  
Left Ventricular ◽  
Diabetic Rat ◽  
Rat Cardiomyocytes ◽  
Zucker Diabetic Fatty Rats

Glucocorticoid receptor (GR) stimulation is essential for normal heart function and dexamethasone (DEX) treatment has been shown to reduce ischemia reperfusion injury (IRI). Prevalence of diabetes is increasing and myocardial infarction in such patients is more severe and risk of complications is augmented. We tested the hypothesis, that GR stimulation with DEX protects diabetic myocardium from IRI by improving Ca cycling. Cardiomyocytes from type 2 diabetic Zucker diabetic fatty rats were isolated and cultured in DEX (10 μg/mL) vs. vehicle for 24h. [Ca] i and fractional shortening (FS) was measured in electrical field-stimulated cardiomyocytes loaded with Fura-2 AM (10 μM). Compared to control, DEX-treated cells display increased Ca transient amplitude (0.33±0.03 vs. 0.46±0.04, P = 0.01, n=6 animals) and FS (fig.) DEX also significantly increased sarcoplasmic reticulum (SR) Ca content (Caffeine, 10 mM) and reduced SR Ca leak measured as Ca spark frequency (SpF), fluo-4 loaded myocytes, confocal microscopy (fig.). To test, whether DEX reduced IRI, rats were treated with DEX (2 mg/kg i.p.) 24h before measurement (vehicle as control). Left ventricular developed pressure (LVDP) was monitored in Langendorff-perfused-hearts during global ischemia for 30 min and reperfusion. During reperfusion, DEX-treated hearts showed significantly greater LVDP (P < 0.05, 2way ANOVA, fig.). In diabetic rats, glucocorticoid receptor stimulation with DEX leads to a more efficient Ca cycling with reduced SR Ca leakage, which translates to an increased contractility on the cellular level and protection against ischemia reperfusion injury in the whole organ.

scholarly journals Cardioprotective Effects of PPARβ/δ Activation against Ischemia/Reperfusion Injury in Rat Heart Are Associated with ALDH2 Upregulation, Amelioration of Oxidative Stress and Preservation of Mitochondrial Energy Production

2021 ◽  
Vol 22 (12) ◽  
pp. 6399
Author(s):  
Ioanna Papatheodorou ◽  
Eleftheria Galatou ◽  
Georgios-Dimitrios Panagiotidis ◽  
Táňa Ravingerová ◽  
Antigone Lazou
Keyword(s):  
Oxidative Stress ◽  
Mrna Expression ◽  
Energy Production ◽  
Citrate Synthase ◽  
Ischemia Reperfusion Injury ◽  
Ex Vivo ◽  
Uncoupling Protein ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Isocitrate Dehydrogenase 2

Accumulating evidence support the cardioprotective properties of the nuclear receptor peroxisome proliferator activated receptor β/δ (PPARβ/δ); however, the underlying mechanisms are not yet fully elucidated. The aim of the study was to further investigate the mechanisms underlying PPARβ/δ-mediated cardioprotection in the setting of myocardial ischemia/reperfusion (I/R). For this purpose, rats were treated with PPARβ/δ agonist GW0742 and/or antagonist GSK0660 in vivo and hearts were subjected to ex vivo global ischemia followed by reperfusion. PPARβ/δ activation improved left ventricular developed pressure recovery, reduced infarct size (IS) and incidence of reperfusion-induced ventricular arrhythmias while it also up-regulated superoxide dismutase 2, catalase and uncoupling protein 3 resulting in attenuation of oxidative stress as evidenced by the reduction in 4-hydroxy-2-nonenal protein adducts and protein carbonyl formation. PPARβ/δ activation also increased both mRNA expression and enzymatic activity of aldehyde dehydrogenase 2 (ALDH2); inhibition of ALDH2 abrogated the IS limiting effect of PPARβ/δ activation. Furthermore, upregulation of PGC-1α and isocitrate dehydrogenase 2 mRNA expression, increased citrate synthase activity as well as mitochondrial ATP content indicated improvement in mitochondrial content and energy production. These data provide new mechanistic insight into the cardioprotective properties of PPARβ/δ in I/R pointing to ALDH2 as a direct downstream target and suggesting that PPARβ/δ activation alleviates myocardial I/R injury through coordinated stimulation of the antioxidant defense of the heart and preservation of mitochondrial function.

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