The Role of Tetrahydrobiopterin and Dihydrobiopterin in Ischemia/Reperfusion Injury When Given at Reperfusion

Reduced nitric oxide (NO) bioavailability and increased oxidative stress are major factors mediating ischemia/reperfusion (I/R) injury. Tetrahydrobiopterin (BH4) is an essential cofactor of endothelial NO synthase (eNOS) to produce NO, whereas dihydrobiopterin (BH2) can shift the eNOS product profile from NO to superoxide, which is further converted to hydrogen peroxide (H2O2) and cause I/R injury. The effects ofBH4andBH2on oxidative stress and postreperfused cardiac functions were examined in ex vivo myocardial and in vivo femoral I (20 min)/R (45 min) models. In femoral I/R,BH4increased NO and decreasedH2O2releases relative to saline control, and these effects correlated with improved postreperfused cardiac function. By contrast,BH2decreased NO release relative to the saline control, but increasedH2O2release similar to the saline control, and these effects correlated with compromised postreperfused cardiac function. In conclusion, these results suggest that promoting eNOS coupling to produce NO and decreaseH2O2may be a key mechanism to restore postreperfused organ function during early reperfusion.

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Nanotoxicology of Dendrimers in the Mammalian Heart: ex vivo and in vivo Administration of G6 PAMAM Nanoparticles Impairs Recovery of Cardiac Function Following Ischemia-Reperfusion Injury

International Journal of Nanomedicine ◽

10.2147/ijn.s255202 ◽

2020 ◽

Vol Volume 15 ◽

pp. 4393-4405

Author(s):

Fawzi Babiker ◽

Ibrahim F Benter ◽

Saghir Akhtar

Keyword(s):

Cardiac Function ◽

Reperfusion Injury ◽

Ischemia Reperfusion Injury ◽

Ex Vivo ◽

Ischemia Reperfusion ◽

Mammalian Heart ◽

In Vivo Administration

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Mixture of MMP-2, MLC, and NOS Inhibitors Affects NO Metabolism and Protects Heart from Cardiac I/R Injury

Cardiology Research and Practice ◽

10.1155/2020/1561478 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Anna Krzywonos-Zawadzka ◽

Aleksandra Franczak ◽

Grzegorz Sawicki ◽

Iwona Bil-Lula

Keyword(s):

Oxidative Stress ◽

Cardiac Function ◽

Ischemia Reperfusion Injury ◽

Ex Vivo ◽

Heart Function ◽

Ischemia Reperfusion ◽

Tissue Expression ◽

Matrix Metalloproteinase 2 ◽

No Production ◽

Nos Inhibitors

Objectives. Coronary reperfusion procedure leads to ischemia/reperfusion injury of the heart (IRI). IRI arises from increased degradation of myosin light chains and increased activity of matrix metalloproteinase 2 (MMP-2). Increased production of toxic peroxynitrite (ONOO−) during oxidative stress is a source of increased nitration/nitrosylation of contractile proteins, which enhance their degradation through MMP-2. Hence, an imbalance in nitric oxide (NO) metabolism along with oxidative stress is an important factor contributing to pathophysiology of cardiovascular disorders, including myocardial infarction. The aim of the current study was to provide an important insight into understanding the interaction of iNOS, eNOS, and ADMA during oxidative stress and to propose the beneficial therapy to modulate this interaction. Material and Methods. Pathogen-free Wistar rats were used in this study as a surrogate heart model ex vivo. Rat hearts perfused using the Langendorff method were subjected to global no-flow ischemia with or without administration of DOXY (1 µM), ML-7 (0.5 µM), and L-NAME (2 µM) mixture. Haemodynamic parameters of heart function, markers of I/R injury, tissue expression of iNOS, eNOS, and phospho-eNOS, asymmetric dimethylarginine, and NO production as well as MMP-2 activity were measured. Results. Mechanical heart function and coronary flow (CF) were decreased in the hearts subjected to I/R. Treatment of the hearts with the tested mixture resulted in a recovery of mechanical function due to decreased activity of MMP‐2. An infusion of Doxy, ML-7, and L-NAME mixture into I/R hearts decreased the expression of iNOS, eNOS, and phospho-eNOS and in consequence reduced ADMA expression. Decreased ADMA production led to enhanced NO synthesis and improvement of cardiac function at 85% of aerobic control. Conclusions. Synergistic effect of the multidrug therapy with the subthreshold doses allows addressing a few pathways of I/R injury simultaneously to achieve protection of cardiac function during I/R.

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Abstract 2487: Ischemia/Reperfusion Injury Impairs Myogenic Tone of Cerebral Vessels in both Ischemic and Nonischemic Hemispheres: Differential Role of Oxidative Stress.

Stroke ◽

10.1161/str.43.suppl_1.a2487 ◽

2012 ◽

Vol 43 (suppl_1) ◽

Author(s):

Maha Coucha ◽

Weiguo Li ◽

Adviye Ergul

Keyword(s):

Oxidative Stress ◽

Wistar Rats ◽

Ischemia Reperfusion Injury ◽

Ex Vivo ◽

Ischemia Reperfusion ◽

Cerebral Arteries ◽

Glucose Deprivation ◽

Myogenic Tone ◽

Ex Vivo Model

Cerebrovascular autoregulation and reactivity are critical to maintain constant perfusion during ischemic brain injury. It is known that ischemia/ reperfusion (I/R) injury and resulting oxidative stress impair vessel reactivity in ischemic hemisphere. Yet the behavior of vessels in nonischemic hemisphere is still unexplored. Hypothesis: I/R injury impairs myogenic tone of vessels in both ischemic and nonischemic hemispheres via increased peroxynitrite (ONOO - ) generation. Methods: Middle cerebral arteries (MCA) isolated from age matched male Wistar rats (n=6) subjected to 30 min MCA occlusion (MCAO)/45 min reperfusion, or MCAO followed by treatment with ONOO - scavenger FeTPPs (20mg/kg) at reperfusion were pressurized in arteriograph chamber. In another set of animals, MCA isolated from control Wistar rats were exposed to ex vivo oxygen-glucose deprivation (OGD) then their myogenic tones across the pressure range were determined. Results: I/R injury impaired myogenic tone of vessels in both ischemic and nonischemic sides albeit to a different degree. Interestingly FeTPPs restored myogenic tone of vessels from ischemic side only ( Table ). Vessels exposed to ex vivo and in vivo hypoxia experienced loss of myogenic tone. The reduction of myogenic tone % by OGD is similar to I/R injury. Conclusion: Our ex vivo model of hypoxia is a valuable method to assess the ischemic insult on vessel reactivity. Increased ONOO - production is one of the underlying mechanisms of loss of tone under I/R injury in ischemic hemisphere, but the impairment of myogenic tone in nonischemic hemisphere involves other mechanisms. Understanding how I/R alters myogenic tone and ultimately cerebral perfusion in both ischemic and nonischemic hemispheres is vital in improving current preventive and therapeutic strategies for acute stroke. + p<0.001, * p< 0.05 vs Sham, # p<0.001 vs ischemic MCA , ** p<0.01 vs nonischemic MCA

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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

International Journal of Molecular Sciences ◽

10.3390/ijms22126399 ◽

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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Abstract 14391: Transient Cell Cycle Induction in Cardiomyocytes is a Promising Approach to Treat Ischemia Induced Heart Failure

Circulation ◽

10.1161/circ.142.suppl_3.14391 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Riham Abouleisa ◽

Qinghui Ou ◽

Xian-liang Tang ◽

Mitesh Solanki ◽

Yiru Guo ◽

...

Keyword(s):

Cell Cycle ◽

Cardiac Function ◽

Single Cell ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Cardiomyocyte Proliferation ◽

Specific Expression ◽

Control Virus

Rationale: The regenerative capacity of the heart to repair itself after myocardial infarction (MI)is limited. Our previous study showed that ectopic introduction of Cdk1/CyclinB1 andCdk4/CyclinD1 complexes (4F) promotes cardiomyocyte proliferation in vitro and in vivo andimproves cardiac function after MI. However, its clinical application is limited due to the concernsfor tumorigenic potential in other organs. Objectives: To first, identify on a single cell transcriptomic basis the necessary reprogrammingsteps that cardiomyocytes need to undertake to progress through the proliferation processfollowing 4F overexpression, and then, to determine the pre-clinical efficacy of transient andcardiomyocyte specific expression of 4F in improving cardiac function after MI in small and largeanimals. Methods and Results: Temporal bulk and single cell RNAseq of mature hiPS-CMs treated with4F or LacZ control for 24, 48, or 72 h revealed full cell cycle reprogramming in 15% of thecardiomyocyte population which was associated with sarcomere disassembly and metabolicreprogramming. Transient overexpression of 4F specifically in cardiomyocytes was achievedusing non-integrating lentivirus (NIL) driven by TNNT2 (TNNT2-4F-NIL). One week after inductionof ischemia-reperfusion injury in rats or pigs, TNNT2-4F-NIL or control virus was injectedintramyocardially. Compared with controls, rats or pigs treated with TNNT2-4F-NIL showed a 20-30% significant improvement in ejection fraction and scar size four weeks after treatment, asassessed by echocardiography and histological analysis. Quantification of cardiomyocyteproliferation in pigs using a novel cytokinesis reporter showed that ~10% of the cardiomyocyteswithin the injection site were labelled as daughter cells following injection with TNNT2-4F-NILcompared with ~0.5% background labelling in control groups. Conclusions: We provide the first understanding of the process of forced cardiomyocyteproliferation and advanced the clinical applicability of this approach through minimization ofoncogenic potential of the cell cycle factors using a novel transient and cardiomyocyte-specificviral construct.

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Galangin Alleviates Liver Ischemia-Reperfusion Injury in a Rat Model by Mediating the PI3K/AKT Pathway

Cellular Physiology and Biochemistry ◽

10.1159/000495553 ◽

2018 ◽

Vol 51 (3) ◽

pp. 1354-1363 ◽

Cited By ~ 7

Author(s):

Yang Li ◽

Liquan Tong ◽

Jingyan Zhang ◽

Yafeng Zhang ◽

Feng Zhang

Keyword(s):

Oxidative Stress ◽

Ischemia Reperfusion Injury ◽

Hepatic Duct ◽

Ischemia Reperfusion ◽

Trauma Surgery ◽

Liver Ischemia ◽

Western Blots ◽

Phosphorylated Akt ◽

Related Proteins

Background/Aims: Liver ischemia-reperfusion (I/R) injury is a pathological process that often occurs during liver and trauma surgery. There are numerous causes of liver I/R injury, but the mechanism is unknown. Galangin (GA) is a flavonoid, a polyphenolic compound widely distributed in medicinal herbs that has anti-inflammatory, antioxidant, and antitumor activity. This study evaluated the protective effect of GA on hepatic I/R injury. Methods: An I/R model was created in male Wistar rats by clamping the hepatoportal vein, hepatic artery and hepatic duct for 30 min followed by reperfusion for 2 h. A hypoxia/restoration (H/R) model was established in buffalo rat liver (BRL) cells by hypoxia for 4 h followed by normoxic conditions for 10 h. The extent of liver injury was assayed by serum ALT/AST, hepatic histology, and MPO activity. Oxidative stress was assayed by serum superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA). Expression of apoptosis-related proteins in BRL cells was assayed in western blots. Expression of AKT and p-AKT proteins in vivo and vitro were assayed in western blots. Results: GA significantly decreased ALT/AST expression, reversed changes in oxidative stress markers induced by I/R, and mediated caspase-3 activity expression of apoptosis-related proteins in vivo and in vitro. Methylthiazol tetrazolium (MTT) assay, flow cytometry, and Hoechst 33258 staining confirmed that GA inhibited apoptosis of BRL cells. GA also increased the expression of phosphorylated AKT after H/R. Conclusion: GA reduced liver I/R injury both in vivo and vitro and inhibited BRL cell apoptosis. PI3K/AKT signaling have been involved. GA may protect against liver I/R and be a potential therapeutic candidate.

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mTOR‐mediated calcium transients affect cardiac function in ex vivo ischemia–reperfusion injury

Physiological Reports ◽

10.14814/phy2.14807 ◽

2021 ◽

Vol 9 (6) ◽

Author(s):

Briana K. Shimada ◽

Naaiko Yorichika ◽

Jason K. Higa ◽

Yuichi Baba ◽

Motoi Kobayashi ◽

...

Keyword(s):

Cardiac Function ◽

Reperfusion Injury ◽

Ischemia Reperfusion Injury ◽

Ex Vivo ◽

Ischemia Reperfusion ◽

Calcium Transients

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Therapeutic Inhibition of Acid Sensing Ion Channel 1a Recovers Heart Function After Ischemia-Reperfusion Injury

Circulation ◽

10.1161/circulationaha.121.054360 ◽

2021 ◽

Author(s):

Meredith A. Redd ◽

Sarah E. Scheuer ◽

Natalie J. Saez ◽

Yusuke Yoshikawa ◽

Han Sheng Chiu ◽

...

Keyword(s):

Ion Channel ◽

Reperfusion Injury ◽

Electromechanical Coupling ◽

Ischemia Reperfusion Injury ◽

Ex Vivo ◽

Heart Function ◽

Ischemia Reperfusion ◽

Genetic Ablation ◽

Organ Level

Background: Ischemia-reperfusion injury (IRI) is one of the major risk factors implicated in morbidity and mortality associated with cardiovascular disease. During cardiac ischemia, the build-up of acidic metabolites results in decreased intracellular and extracellular pH that can reach as low as 6.0-6.5. The resulting tissue acidosis exacerbates ischemic injury and significantly impacts cardiac function. Methods: We used genetic and pharmacological methods to investigate the role of acid sensing ion channel 1a (ASIC1a) in cardiac IRI at the cellular and whole organ level. Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) as well as ex vivo and in vivo models of IRI were used to test the efficacy of ASIC1a inhibitors as pre- and post-conditioning therapeutic agents. Results: Analysis of human complex trait genetics indicate that variants in the ASIC1 genetic locus are significantly associated with cardiac and cerebrovascular ischemic injuries. Using hiPSC-CMs in vitro and murine ex vivo heart models, we demonstrate that genetic ablation of ASIC1a improves cardiomyocyte viability after acute IRI. Therapeutic blockade of ASIC1a using specific and potent pharmacological inhibitors recapitulates this cardioprotective effect. We used an in vivo model of myocardial infarction (MI) and two models of ex vivo donor heart procurement and storage as clinical models to show that ASIC1a inhibition improves post-IRI cardiac viability. Use of ASIC1a inhibitors as pre- or post-conditioning agents provided equivalent cardioprotection to benchmark drugs, including the sodium-hydrogen exchange inhibitor zoniporide. At the cellular and whole organ level, we show that acute exposure to ASIC1a inhibitors has no impact on cardiac ion channels regulating baseline electromechanical coupling and physiological performance. Conclusions: Collectively, our data provide compelling evidence for a novel pharmacological strategy involving ASIC1a blockade as a cardioprotective therapy to improve the viability of hearts subjected to IRI.

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Mangiferin Attenuates Myocardial Ischemia-Reperfusion Injury via MAPK/Nrf-2/HO-1/NF-κB In Vitro and In Vivo

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/7285434 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Kun Liu ◽

Fei Wang ◽

Shuo Wang ◽

Wei-Nan Li ◽

Qing Ye

Keyword(s):

Oxidative Stress ◽

Coronary Artery ◽

Myocardial Injury ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

H9c2 Cells ◽

Myocardial Ischemia Reperfusion Injury ◽

Myocardial Ischemia Reperfusion

The aim of this study was to investigate the cardioprotective effect of mangiferin (MAF) in vitro and in vivo. Oxidative stress and inflammatory injury were detected in coronary artery ligation in rats and also in hypoxia-reoxygenation- (H/R-) induced H9c2 cells. MAF inhibited myocardial oxidative stress and proinflammatory cytokines in rats with coronary artery occlusion. The ST segment of MAF treatment groups also resumed. Triphenyltetrazolium chloride (TTC) staining and pathological analysis showed that MAF could significantly reduce myocardial injury. In vitro data showed that MAF could improve hypoxia/reoxygenation- (H/R-) induced H9c2 cell activity. In addition, MAF could significantly reduce oxidative stress and inflammatory pathway protein expression in H/R-induced H9c2 cells. This study has clarified the protective effects of MAF on myocardial injury and also confirmed that oxidative stress and inflammation were involved in the myocardial ischemia-reperfusion injury (I/R) model.

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