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.

Antioxidant tempol suppresses heart cytosolic phospholipase A2α stimulated by chronic intermittent hypoxia

2017 ◽  
Vol 95 (8) ◽  
pp. 920-927 ◽  
Author(s):  
Petra Míčová ◽  
Martina Klevstig ◽  
Kristýna Holzerová ◽  
Marek Vecka ◽  
Jitka Žurmanová ◽  
...  
Keyword(s):  
Intermittent Hypoxia ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Chronic Intermittent Hypoxia ◽  
Acute Ischemia ◽  
Left Ventricular Myocardium ◽  
Ros Generation ◽  
Mrna Levels

Adaptation to chronic intermittent hypoxia (CIH) is associated with reactive oxygen species (ROS) generation implicated in the improved cardiac tolerance against acute ischemia–reperfusion injury. Phospholipases A2(PLA2s) play an important role in cardiomyocyte phospholipid metabolism influencing membrane homeostasis. Here we aimed to determine the effect of CIH (7000 m, 8 h/day, 5 weeks) on the expression of cytosolic PLA2(cPLA2α), its phosphorylated form (p-cPLA2α), calcium-independent (iPLA2), and secretory (sPLA2IIA) at protein and mRNA levels, as well as fatty acids (FA) profile in left ventricular myocardium of adult male Wistar rats. Chronic administration of antioxidant tempol was used to verify the ROS involvement in CIH effect on PLA2s expression and phospholipid FA remodeling. While CIH did not affect PLA2s mRNA levels, it increased the total cPLA2α protein in cytosol and membranes (by 191% and 38%, respectively) and p-cPLA2α (by 23%) in membranes. On the contrary, both iPLA2and sPLA2IIA were downregulated by CIH. CIH further decreased phospholipid n-6 polyunsaturated FA (PUFA) and increased n-3 PUFA proportion. Tempol treatment prevented only CIH-induced cPLA2α up-regulation and its phosphorylation on Ser505. Our results show that CIH diversely affect myocardial PLA2s and suggest that ROS are responsible for the activation of cPLA2α under these conditions.

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.

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.

Silencing of sodium/hydrogen exchanger in the heart by direct injection of naked siRNA

2011 ◽  
Vol 111 (2) ◽  
pp. 566-572 ◽  
Author(s):  
Patricio E. Morgan ◽  
María V. Correa ◽  
Irene L. Ennis ◽  
Ariel A. Diez ◽  
Néstor G. Pérez ◽  
...  
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Direct Injection ◽  
Experimental Models ◽  
Left Ventricular ◽  
Maximal Velocity ◽  
Mrna Levels ◽  
Small Interference Rna

Cardiac Na+/H+ exchanger (NHE1) hyperactivity is a central factor in cardiac remodeling following hypertension, myocardial infarction, ischemia-reperfusion injury, and heart failure. Treatment of these pathologies by inhibiting NHE1 is challenging because specific drugs that have been beneficial in experimental models were associated with undesired side effects in clinical practice. In the present work, small interference RNA (siRNA) produced in vitro to specifically silence NHE1 (siRNANHE1) was injected once in vivo into the apex of the left ventricular wall of mouse myocardium. After 48 h, left ventricular NHE1 protein expression was reduced in siRNANHE1-injected mice compared with scrambled siRNA by 33.2 ± 3.4% ( n = 5; P < 0.05). Similarly, NHE1 mRNA levels were reduced by 20 ± 2.0% ( n = 4). At 72 h, siRNANHE1 spreading was evident from the decrease in NHE1 expression in three portions of the myocardium (apex, medium, base). NHE1 function was assessed based on maximal velocity of intracellular pH (pHi) recovery (dpHi/d t) after an ammonium prepulse-induced acidic load. Maximal dpHi/d t was reduced to 14% in siRNANHE1-isolated left ventricular papillary muscles compared with scrambled siRNA. In conclusion, only one injection of naked siRNANHE1 successfully reduced NHE1 expression and activity in the left ventricle. As has been previously suggested, extensive NHE1 expression reduction may indicate myocardial spread of siRNA molecules from the injection site through gap junctions, providing a valid technique not only for further research into NHE1 function, but also for consideration as a potential therapeutic strategy.

IKKβ inhibition attenuates myocardial injury and dysfunction following acute ischemia-reperfusion injury

2007 ◽  
Vol 293 (4) ◽  
pp. H2248-H2253 ◽  
Author(s):  
Nancy C. Moss ◽  
William E. Stansfield ◽  
Monte S. Willis ◽  
Ru-Hang Tang ◽  
Craig H. Selzman
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Cardiac Injury ◽  
Myocardial Damage ◽  
Nuclear Factor Κb ◽  
Left Ventricular ◽  
Acute Ischemia ◽  
Artery Ligation ◽  
Cardiac Morbidity

Despite years of experimental and clinical research, myocardial ischemia-reperfusion (IR) remains an important cause of cardiac morbidity and mortality. The transcription factor nuclear factor-κB (NF-κB) has been implicated as a key mediator of reperfusion injury. Activation of NF-κB is dependent upon the phosphorylation of its inhibitor, IκBα, by the specific inhibitory κB kinase (IKK) subunit, IKKβ. We hypothesized that specific antagonism of the NF-κB inflammatory pathway through IKKβ inhibition reduces acute myocardial damage following IR injury. C57BL/6 mice underwent left anterior descending (LAD) artery ligation and release in an experimental model of acute IR. Bay 65-1942, an ATP-competitive inhibitor that selectively targets IKKβ kinase activity, was administered intraperitoneally either prior to ischemia, at reperfusion, or 2 h after reperfusion. Compared with untreated animals, mice treated with IKKβ inhibition had significant reduction in left ventricular infarct size. Cardiac function was also preserved following pretreatment with IKKβ inhibition. These findings were further associated with decreased expression of phosphorylated IκBα and phosphorylated p65 in myocardial tissue. In addition, IKKβ inhibition decreased serum levels of TNF-α and IL-6, two prototypical downstream effectors of NF-κB activity. These results demonstrate that specific IKKβ inhibition can provide both acute and delayed cardioprotection and offers a clinically accessible target for preventing cardiac injury following IR.

Abstract 19837: DJ-1/Park7 Protects the Heart Against Ischemia-reperfusion Injury Through the Modulation of SUMOylation (Best of Basic Science Abstract)

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Yuuki Shimizu ◽  
Larry Barr ◽  
Travis Fields ◽  
John W Calvert
Keyword(s):  
Protein Expression ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Cell Injury ◽  
Troponin I ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Mrna Levels ◽  
Modified Proteins

Background: DJ-1/Park7 is a ubiquitously expressed protein typically associated with the development of early onset Parkinson’s disease. Recent data suggests that it also plays a role in the cellular response to stress. Although much is known about DJ-1 in the brain, very little has been investigated in the heart. Here, we aimed to examine the underlying molecular mechanisms mediating the actions of DJ-1 in the heart following the onset of myocardial ischemia-reperfusion (I/R) injury. Methods and Results: Wild-type (WT) control and DJ-1 deficient (DJ-1 KO) mice were subjected to in vivo myocardial I/R injury. DJ-1 KO mice (n=9) displayed increased areas of infarction (%INF/LV or AAR: 30.2 vs 22.0%, 53.6 vs 39.0%, Troponin-I: 47.4 vs 19.9ng/ml, p<0.05 respectively) and worsened left ventricular function (LVEF: 43.7 vs 58.1%, p<0.001) when compared to WT mice (n=9), confirming a protective role for DJ-1 in the heart. In an effort to evaluate the potential mechanism(s) responsible for the increased injury in DJ-1 KO mice, we focused on SUMOylation, a post-translational modification process which regulates various aspects of protein function, including transcription, subcellular localization, DNA repair, and cell cycle. DJ-1 KO hearts after I/R injury were found to display enhanced accumulation of SUMO-1 modified proteins, (this modification is generally associated with cell injury), and reduced SUMO-2/3 modified proteins (this modification is generally associated with cytoprotection). Further analysis, revealed that the protein expression of the de-SUMOylation enzyme SENP-1 (removes SUMO-1 modifications) was reduced, whereas the expression of SENP-5 (removes SUMO-2/3 modifications) was enhanced in DJ-1 KO hearts after I/R injury. Changes in mRNA levels did not account for the altered protein expression of SENP-1 and SENP-5. So, we evaluated the direct interaction of DJ-1 with both proteins in hearts of WT mice following I/R using co-immunoprecipitation. We found that SENP1 binding with DJ-1 was down-regulated, whereas SENP5 binding with DJ-1 was up-regulated. Conclusion: Our data demonstrated that the activation of DJ-1 in response to myocardial I/R injury protects the heart by the modulation of SUMOylation via direct binding of SENP1 and SENP5.

Human Mesenchymal Stem Cell-derived Exosomes Reduce Ischemia/Reperfusion Injury by the Inhibitions of Apoptosis and Autophagy

2019 ◽  
Vol 24 (44) ◽  
pp. 5334-5341 ◽  
Author(s):  
Xiaofei Jiang ◽  
Kar-Sheng Lew ◽  
Qiying Chen ◽  
Arthur M. Richards ◽  
Peipei Wang
Keyword(s):  
Stem Cell ◽  
Mesenchymal Stem Cell ◽  
Cell Viability ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Isolated Heart ◽  
Ischemia Reperfusion ◽  
Human Mesenchymal Stem Cell ◽  
Ldh Release ◽  
Induced Apoptosis

Background: Human mesenchymal stem cell-derived exosomes (hMSC-Exo) have been shown to reduce ischemia/reperfusion injury (I/R) in multiple models. I/R-induced apoptosis or autophagy play important roles in cell death. However, little or no reports demonstrate any roles of hMSC-Exo in this regards. Objective: To test the hypothesis that the inhibition of I/R-induced apoptosis and autophagy play a pivotal role in the cardioprotection of hMSC-Exo. Methods: Myoblast H9c2 cells and isolated rat hearts underwent hypoxia/re-oxygenate (H/R) or ischemia/ reperfusion (I/R) respectively. H9c2 were treated with 1.0 μg/ml Exo, in comparison with 3-MA or rapamycin (Rapa), a known anti- or pro-autophagic agent respectively. Hearts were treated with 0.5, 1.0 and 2.0 μg/ml Exo for 20 min in the beginning of reperfusion. Cell viability, WST assay, LDH release, Annexin-V staining apoptosis assay and GFP-LC3 labeled autophagosomes formation, cardiac function and Western blot were measured. Results: Exo significantly reduced H/R injury as indicated by increased cell viability and reduced LDH and apoptosis. 3-MA, while Rapa, showed increased or decreased protective effects. Rapa-induced injury was partially blocked by Exo. Exo decreased LC3-II/I ratio and increased p62, inhibited autophagosome formation, an indication of autophagy inhibition. In isolated heart, Exo increased cardiac functional recovery and reduced LDH release in I/R. Bcl-2 was significantly upregulated by Exo but not 3-MA. Exo downregulated Traf6 and upregulated mTORC1/p-4eBP1. Conclusion: Exo reduce I/R-induced apoptosis and autophagy. Up-regulation of Bcl-2 is the cross-talk between these two processes. The down-regulation of Traf6 and activation of mTORC1 are additional mechanisms in the inhibition of apoptosis and autophagy.

Ischemia–reperfusion injury stimulates gelatinase expression and activity in kidney glomeruli

2005 ◽  
Vol 83 (3) ◽  
pp. 287-300 ◽  
Author(s):  
Annick Caron ◽  
Richard R Desrosiers ◽  
Stéphanie Langlois ◽  
Richard Béliveau
Keyword(s):  
Renal Failure ◽  
Acute Renal Failure ◽  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Gelatin Zymography ◽  
Acute Ischemia ◽  
Mrna Levels ◽  
Gelatinase Activity ◽  
Stimulation Of

Although ischemia remains the leading cause of acute renal failure in humans, there is little information on the expression and activities of gelatinases of kidney glomeruli during ischemia–reperfusion injury. In this study, we used a unilateral ischemia–reperfusion model to investigate the activity and expression of gelatinases in glomeruli during acute ischemia. Unilateral ischemia was induced in rats by vascular clamping (30 min) followed by reperfusion (60 min) and isolation of glomeruli. The activity and expression of gelatinase proteins were determined by gelatin zymography and Western blotting. Gelatinase mRNA levels were evaluated by reverse transciptase-PCR. Ischemia and reperfusion increased serum creatinine levels, hallmark of acute renal failure. Ischemia induced mRNA and protein MMP-2 expression. There was strong stimulation of MMP-9 mRNA, both forms of dimeric MMP-9, and active mono meric MMP-9. In contrast to TIMP-1 decreasing, TIMP-2 protein and mRNA increased during ischemia. During reperfusion, there was a gradual reversal of the MMP-2 and MMP-9 levels and a strong inhibition of TIMP-1 and TIMP-2 at the protein and mRNA levels. Endocytic receptor LRP was increased during ischemia and returned to normal during reperfusion. Expression of MMP-9 docking receptor CD-44 was increased during reperfusion. Finally, ZO-1, an in vivo MMP-9 substrate, was degraded during ischemia, revealing that MMP-9 upregulated during ischemia was functional. Our data suggest that stimulation of gelatinase activity during ischemia could contribute to glomeruli injury, providing new therapeutic targets for acute renal failure in humans. In contrast, elevated monomeric MMP-9 activity due to TIMP-1 decrease during reperfusion may participate to glomerular recovery.Key words: gelatinases, ischemia-reperfusion, TIMPs, ZO-1, CD-44, LRP, glomeruli.

Effects of diet-induced obesity on inflammation and remodeling after myocardial infarction

2006 ◽  
Vol 291 (5) ◽  
pp. H2504-H2514 ◽  
Author(s):  
Geeta D. Thakker ◽  
Nikolaos G. Frangogiannis ◽  
Marcin Bujak ◽  
Paul Zymek ◽  
John W. Gaubatz ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Insulin Resistance ◽  
Cardiac Hypertrophy ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Cardiovascular Effects ◽  
Left Ventricular ◽  
Mrna Levels ◽  
Diet Induced Obesity ◽  
Macrophage Density

Epidemiological studies indicate that obesity, insulin resistance, and diabetes are important comorbidities of patients with ischemic heart disease and increase mortality and development of congestive heart failure after myocardial infarction. Although ob/ob and db/db mice are commonly used to study obesity with insulin resistance or diabetes, mutations in the leptin gene or its receptor are rarely the cause of obesity in humans, which is, instead, primarily a consequence of dietary and lifestyle factors. Therefore, we used a murine model of diet-induced obesity to examine the physiological effects of obesity and the inflammatory and healing response of diet-induced obese (DIO) mice after myocardial ischemia-reperfusion injury. DIO mice developed hyperinsulinemia and insulin resistance and hepatic steatosis, with significant ectopic lipid deposition in the heart and cardiac hypertrophy in the absence of significant changes in blood pressure. The mRNA levels of chemokines at 24 h and cytokines at 24 and 72 h of reperfusion were higher in DIO than in lean mice. In granulation tissue at 72 h of reperfusion, macrophage density was significantly increased, whereas neutrophil density was reduced, in DIO mice compared with lean mice. At 7 days of reperfusion, collagen deposition in the scar was significantly reduced and left ventricular (LV) dilation and cardiac hypertrophy were increased, indicative of adverse LV remodeling, in infarcted DIO mice. Characterization of a murine diet-induced model of obesity and insulin resistance that satisfies many aspects commonly observed in human obesity allows detailed examination of the adverse cardiovascular effects of diet-induced obesity at the molecular level.

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.

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