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Ferroptosis is a pervasive non-apoptotic form of cell death highly relevant in various degenerative diseases and malignancies. The hallmark of ferroptosis is uncontrolled and overwhelming peroxidation of polyunsaturated fatty acids contained in membrane phospholipids, which eventually leads to rupture of the plasma membrane. Ferroptosis is unique in that it is essentially a spontaneous, uncatalyzed chemical process based on perturbed iron and redox homeostasis contributing to the cell death process, but that it is nonetheless modulated by many metabolic nodes that impinge on the cells susceptibility to ferroptosis. Among the various nodes affecting ferroptosis sensitivity, several have emerged as promising candidates for pharmacological intervention, rendering ferroptosis-related proteins attractive targets for the treatment of numerous currently incurable diseases. Herein, the current members of a Germany-wide research consortium focusing on ferroptosis research, as well as key external experts in ferroptosis who have made seminal contributions to this rapidly growing and exciting field of research, have gathered to provide a comprehensive, state-of-the-art review on ferroptosis. Specific topics include: basic mechanisms, in vivo relevance, specialized methodologies, chemical and pharmacological tools, and the potential contribution of ferroptosis to disease etiopathology and progression. We hope that this article will not only provide established scientists and newcomers to the field with an overview of the multiple facets of ferroptosis, but also encourage additional efforts to characterize further molecular pathways modulating ferroptosis, with the ultimate goal to develop novel pharmacotherapies to tackle the various diseases associated with - or caused by - ferroptosis.

BACKGROUND: Elephant seals exhibit extreme hypoxemic tolerance derived from repetitive hypoxia/reoxygenation episodes they experience during diving bouts. Real-time assessment of the molecular changes underlying protection against hypoxic injury in seals remains restricted by their at-sea inaccessibility. Hence, we developed a proliferative arterial endothelial cell culture model from elephant seals and used RNA-seq, functional assays, and confocal microscopy to assess the molecular response to prolonged hypoxia. RESULTS: Seal and human endothelial cells exposed to 1% O2 for up to 6 h respond differently to acute and prolonged hypoxia. Seal cells decouple stabilization of the hypoxia-sensitive transcriptional regulator HIF-1α from angiogenic signaling. Rapid upregulation of genes involved in glutathione (GSH) metabolism supports the maintenance of GSH pools, and intracellular succinate increases in seal but not human cells. High maximal and spare respiratory capacity in seal cells after hypoxia exposure occurs in concert with increasing mitochondrial branch length and independent from major changes in extracellular acidification rate, suggesting that seal cells recover oxidative metabolism without significant glycolytic dependency after hypoxia exposure. CONCLUSIONS: We found that the glutathione antioxidant system is upregulated in seal endothelial cells during hypoxia, while this system remains static in comparable human cells. Furthermore, we found that in contrast to human cells, hypoxia exposure rapidly activates HIF-1 in seal cells, but this response is decoupled from the canonical angiogenesis pathway. These results highlight the unique mechanisms that confer extraordinary tolerance to limited oxygen availability in a champion diving mammal.

Cardiorenal diseases represent a complex interplay between heart failure and renal dysfunction, being clinically classified as cardiorenal syndromes (CRS). Recently, the contributions of altered nicotinamide adenine dinucleotide (NAD+) metabolism, through deficient NAD+ synthesis and/or elevated consumption, have proved to be decisive in the onset and progress of cardiorenal disease. NAD+ is a pivotal coenzyme in cellular metabolism, being significant in various signaling pathways, such as energy metabolism, DNA damage repair, gene expression, and stress response. Convincing evidence suggests that strategies designed to boost cellular NAD+ levels are a promising therapeutic option to address cardiovascular and renal disorders. Here, we review and discuss the implications of NAD+ metabolism in cardiorenal diseases, focusing on the propitious NAD+ boosting therapeutic strategies, based on the use of NAD+ precursors, poly(ADP-ribose) polymerase inhibitors, sirtuin activators, and other alternative approaches, such as CD38 blockade, nicotinamide phosphoribosyltransferase activation and combined interventions. [ABSTRACT FROM AUTHOR]

Stroke remains one of the major health challenges due to its high rates of mortality and long-term disability, necessitating the development of effective therapeutic treatment. This study aims to explore the neuroprotective effects of hypoxic postconditioning (HPC) using a cell-based 3D cortical ischemic-hypoxic injury model. Our model employs murine cells to investigate HPC-induced modulation of glial cell reactivity and intercommunication post-oxygen-glucose deprivation-reoxygenation (OGD-R) injury. We found that a single HPC session (1HPC) provided the most significant neuroprotection post-OGD-R compared to multiple intermittent hypoxic treatments, evidenced by improved spheroidal structure, enhanced cell survival and reduced apoptosis, optimal modulation of neuronal phenotypes, dampened ischemic responses, and augmented neurite outgrowth of spheroids. Furthermore, 1HPC suppressed both pro-inflammatory A1 and anti-inflammatory A2 astrocyte phenotypes despite the induction of astrocyte activation while reducing microglial activation with inhibited M1 and M2 reactive states. This was accompanied by a decrease in gene expression of the pro-inflammatory cytokines essential to microglia-astrocyte signaling, collectively suggesting a shift of glial cells away from their traditional reactive states for neuroprotection. This study highlights the potential of 1HPC as a novel therapeutic intervention for ischemic injury via the modulation of neuroprotective glial reactivity. Moreover, the 3D cortical ischemic-hypoxic injury model employed here holds enormous potential serving as a disease model to further elucidate the underlying mechanism of HPC, which can also extend to the applications in brain regeneration, drug development, and the modeling of neural diseases. [ABSTRACT FROM AUTHOR]

Background and objective: This study aimed to assess the protective ability of edaravone on testicular torsion–detorsion injury in rats. Methods: Eighteen adult male Sprague–Dawley rats were randomly divided into three groups: Sham group (control, n = 6); testicular torsion/detorsion (T/D group, n = 6) and T/D+edaravone (T/D+E group, n = 6). The spermatic cords of rats of the T/D group and the T/D+E group were rotated 720° in a clockwise direction and maintained for 120 min in this torsion position. Around 90 min after the torsion, edaravone at a dose of 10 mg/kg dissolved in saline was administered IP to the T/D+E group. The testicle was counter‐rotated to its normal position to allow reperfusion for 4 h. Left testes of each animal were excised 240 min after beginning of reperfusion. Oxidative stress markers (TAS, TOS, SOD, and MDA) and apoptotic pathways (Caspase 3, Caspase 8, Caspase 9, Bcl‐2, and Bax,) were assessed by ELISA methods. Also, testicles were subjected to the histopathologic and ultrasound examinations. Results: Ultrasound imaging showed that edaravone reduced the surface area and increased vascularization in testicles with T/D (p < 0.0001, p < 0.05, respectively). Edaravone pretreatment markedly decreased the levels of MDA, TOS, Bcl‐2, Bax, Caspase 3, Caspase 8, and Caspase 9 (p < 0.0001). Also, it increased significantly TAS levels (p < 0.0001) and reduced insignificantly SOD activity. Histopathologic examinations demonstrated that edaravone significantly attenuated the histological damage caused by T/D in testicles. Conclusion: Taken together, the findings indicate that pretreatment of edaravone has protective effect against testicular T/D injury. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) is a devastating clinical condition characterized by an abrupt loss of renal function. The pathophysiology of AKI involves diverse processes and elements, of which survival and regeneration have been established to be significant hallmarks. And early studies have confirmed the fundamental role of FGFs in the regulation of AKI pathology, although the association between FGF18 and AKI still remains elusive. Our study demonstrates a substantial up‐regulation of FGF18 in the renal tubules of mice subjected to ischemia. Notably, targeted overexpression of FGF18 effectively mitigates the impairment of kidney function induced by AKI. Mechanistically, FGF18 facilitates cell proliferation and anti‐apoptosis in RTECs by enhancing the expression of YAP and facilitating its translocation to the nucleus. Aside from that, we also discovered that the substantial expression of FGF18 under ischemic conditions is HIF‐1α dependent. This study aims to uncover the inherent mechanism behind the beneficial effects of FGF18 in attenuating AKI. By doing so, it aims to offer novel insights into the development of therapeutic strategies for AKI. [ABSTRACT FROM AUTHOR]

Endothelial dysfunction (ED) is closely associated with most cardiovascular diseases. Experimental models are needed to analyze the potential impact of ED on cardioprotection in constant pressure Langendorff systems (CPLS). One cardioprotective strategy against ischemia/reperfusion injury (I/RI) is conditioning with the lipid emulsion Intralipid (IL). Whether ED modulates the cardioprotective effect of IL remains unknown. The aim of the study was to transfer a protocol using a constant flow Langendorff system for the induction of ED into a CPLS, without the loss of smooth muscle cell functionality, and to analyze the cardioprotective effect of IL against I/RI under ED. In isolated hearts of male Wistar rats, ED was induced by 10 min perfusion of a Krebs–Henseleit buffer containing 60 mM KCl (K+), and the vasodilatory response to the vasodilators histamine (endothelial-dependent) and sodium–nitroprusside (SNP, endothelial-independent) was measured. A CPLS was employed to determine cardioprotection of pre- or postconditioning with 1% IL against I/RI. The constant flow perfusion of K+ reduced endothelial response to histamine but not to SNP, indicating reduced vasodilatory functionality of endothelial cells but not smooth muscle cells. Preconditioning with IL reduced infarct size and improved cardiac function while postconditioning with IL had no effect. The induction of ED neither influenced infarct size nor affected the cardioprotective effect by preconditioning with IL. This protocol allows for studies of cardioprotective strategies under ED in CLPS. The protection by preconditioning with IL seems to be mediated independently of a functional endothelium. [ABSTRACT FROM AUTHOR]

Background: Ischemia/reperfusion (I/R) injury is a severe brain disorder with currently limited effective treatments. This study aims to explore the role of N6-methyladenosine (m6A) modification and associated regulatory factors in I/R to identify potential therapeutic targets. Methods: We utilized a middle cerebral artery occlusion (MCAO) rat model and SH-SY5Y cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to assess m6A levels and investigate the impact of METTL3 overexpression on long non-coding RNA (lncRNA) CRNDE expression. The effects of silencing lncRNA CRNDE on the interaction between YTHDC1 and ATG10 mRNA, as well as the stability of ATG10 mRNA, were evaluated. Additionally, apoptosis rates, pro-inflammatory and anti-inflammatory factor levels, ATG10 expression, and autophagic activity were analyzed to determine the effects of METTL3. The reverse effects of YTHDC1 overexpression were also examined. Results: MCAO rats and OGD/R-treated SH-SY5Y cells exhibited reduced m6A levels. METTL3 overexpression significantly inhibited lncRNA CRNDE expression. Silencing lncRNA CRNDE mitigated OGD/R-induced apoptosis and inflammation in SH-SY5Y cells, while enhancing autophagy and stabilizing ATG10 mRNA. METTL3 overexpression decreased cell apoptosis, reduced the levels of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and increased IL-10 secretion. Furthermore, METTL3 overexpression upregulated ATG10 expression and promoted autophagy. Conversely, lncRNA CRNDE overexpression negated these effects. Conclusion: The inhibition of lncRNA CRNDE affects the interaction between YTHDC1 and ATG10 mRNA and stabilizes ATG10 mRNA, mediated by METTL3 overexpression. These findings suggest that targeting lncRNA CRNDE to reduce apoptosis, inhibit inflammation, increase ATG10 expression, and enhance autophagy could offer new therapeutic strategies for I/R injury. [ABSTRACT FROM AUTHOR]

Ischemia/reperfusion (I/R) is an important inducer of acute kidney injury (AKI), and triggers the generation of reactive oxygen species (ROS) and the expression of matrix metalloproteinase 2 (MMP2), exacerbating kidney damage. Given the immense potential of vitamin E (VitE) as a natural fat-soluble antioxidant in kidney protection, we designed the nanoparticles (NPs) that could dual respond to ROS and MMP2, aiming to accurately deliver VitE to renal injury cells. The NPs utilized Gel-SH as a sensitive receptor for MMP2 and diselenide as a sensitive receptor for ROS, while PEG2k modification enhanced biocompatibility and prevented phagocytosis mediated by the mononuclear phagocyte system. The amphiphilic Gel-SH and diselenide encapsulate the liposoluble VitE and self-assemble into the NPs with a hydrodynamic size of 69.92 nm. Both in vivo and in vitro experiments based on these NPs show good biocompatibility and the ability of target renal injury cells. In vivo kidney I/R injury models and in vitro cell hypoxia/reoxygenation models, the NPs have demonstrated effects in reducing oxidative stress and alleviating AKI. Notably, VitE can preferentially react with peroxyl radical (LOO•) than polyunsaturated fatty acid (PUFA), inhibiting the formation of carbon centered radical (L•), thereby blocking the chain reaction between PUFA and LOO• in ferroptosis. The NPs also inhibit the transition from AKI to chronic kidney disease, with few side effects. Thus, the NPs with dual-responsiveness to MMP2 and ROS for targeted delivery of VitE to renal injury cells exhibit remarkable effects in inhibiting ROS and the chain reactions of ferroptosis, making it a promising therapeutic agent against AKI caused by I/R. [ABSTRACT FROM AUTHOR]

Reperfusion after myocardial infarction (MI) can lead to myocardial ischemia/reperfusion (I/R) damage. The transcription factor (TF) broad-complex, tramtrack, and bric-a-brac (BTB) and cap'n'collar (CNC) homology 1 (BACH1) is implicated in the injury. However, the downstream mechanisms of BACH1 in affecting myocardial hypoxia/reoxygenation (H/R) damage are still fully understood. AC16 cells were stimulated with H/R conditions to model cardiomyocytes under H/R. mRNA analysis was performed by quantitative real-time PCR. Protein levels were gauged by immunoblot analysis. The effect of BACH1/cyclin-dependent kinase inhibitor 3 (CDKN3) on H/R-evoked injury was assessed by measuring cell viability via Cell Counting Kit-8 (CCK-8), apoptosis (flow cytometry and caspase 3 activity), ferroptosis via Fe2+, glutathione (GSH), reactive oxygen species (ROS) and malondialdehyde (MDA) markers and inflammation cytokines interleukin-1beta (IL-1β) and tumor necrosis factor alpha (TNF-α). The BACH1/CDKN3 relationship was examined by chromatin immunoprecipitation (ChIP) experiment and luciferase assay. BACH1 was increased in MI serum and H/R-stimulated AC16 cardiomyocytes. Functionally, disruption of BACH1 mitigated H/R-evoked in vitro apoptosis, ferroptosis and inflammation of AC16 cardiomyocytes. Mechanistically, BACH1 activated CDKN3 transcription and enhanced CDKN3 protein expression in AC16 cardiomyocytes. Our rescue experiments validated that BACH1 disruption attenuated H/R-evoked AC16 cardiomyocyte apoptosis, ferroptosis and inflammation by downregulating CDKN3. Additionally, BACH1 disruption could activate the adenosine monophosphate-activated protein kinase (AMPK) signaling by downregulating CDKN3 in H/R-stimulated AC16 cardiomyocytes. Our study demonstrates that BACH1 activates CDKN3 transcription to induce H/R-evoked damage of AC16 cardiomyocytes partially via AMPK signaling. [ABSTRACT FROM AUTHOR]

Abstract Stroke remains one of the major health challenges due to its high rates of mortality and long-term disability, necessitating the development of effective therapeutic treatment. This study aims to explore the neuroprotective effects of hypoxic postconditioning (HPC) using a cell-based 3D cortical ischemic-hypoxic injury model. Our model employs murine cells to investigate HPC-induced modulation of glial cell reactivity and intercommunication post-oxygen-glucose deprivation-reoxygenation (OGD-R) injury. We found that a single HPC session (1HPC) provided the most significant neuroprotection post-OGD-R compared to multiple intermittent hypoxic treatments, evidenced by improved spheroidal structure, enhanced cell survival and reduced apoptosis, optimal modulation of neuronal phenotypes, dampened ischemic responses, and augmented neurite outgrowth of spheroids. Furthermore, 1HPC suppressed both pro-inflammatory A1 and anti-inflammatory A2 astrocyte phenotypes despite the induction of astrocyte activation while reducing microglial activation with inhibited M1 and M2 reactive states. This was accompanied by a decrease in gene expression of the pro-inflammatory cytokines essential to microglia-astrocyte signaling, collectively suggesting a shift of glial cells away from their traditional reactive states for neuroprotection. This study highlights the potential of 1HPC as a novel therapeutic intervention for ischemic injury via the modulation of neuroprotective glial reactivity. Moreover, the 3D cortical ischemic-hypoxic injury model employed here holds enormous potential serving as a disease model to further elucidate the underlying mechanism of HPC, which can also extend to the applications in brain regeneration, drug development, and the modeling of neural diseases.

Abstract Background Ischemia/reperfusion (I/R) injury is a severe brain disorder with currently limited effective treatments. This study aims to explore the role of N6-methyladenosine (m6A) modification and associated regulatory factors in I/R to identify potential therapeutic targets. Methods We utilized a middle cerebral artery occlusion (MCAO) rat model and SH-SY5Y cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to assess m6A levels and investigate the impact of METTL3 overexpression on long non-coding RNA (lncRNA) CRNDE expression. The effects of silencing lncRNA CRNDE on the interaction between YTHDC1 and ATG10 mRNA, as well as the stability of ATG10 mRNA, were evaluated. Additionally, apoptosis rates, pro-inflammatory and anti-inflammatory factor levels, ATG10 expression, and autophagic activity were analyzed to determine the effects of METTL3. The reverse effects of YTHDC1 overexpression were also examined. Results MCAO rats and OGD/R-treated SH-SY5Y cells exhibited reduced m6A levels. METTL3 overexpression significantly inhibited lncRNA CRNDE expression. Silencing lncRNA CRNDE mitigated OGD/R-induced apoptosis and inflammation in SH-SY5Y cells, while enhancing autophagy and stabilizing ATG10 mRNA. METTL3 overexpression decreased cell apoptosis, reduced the levels of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and increased IL-10 secretion. Furthermore, METTL3 overexpression upregulated ATG10 expression and promoted autophagy. Conversely, lncRNA CRNDE overexpression negated these effects. Conclusion The inhibition of lncRNA CRNDE affects the interaction between YTHDC1 and ATG10 mRNA and stabilizes ATG10 mRNA, mediated by METTL3 overexpression. These findings suggest that targeting lncRNA CRNDE to reduce apoptosis, inhibit inflammation, increase ATG10 expression, and enhance autophagy could offer new therapeutic strategies for I/R injury.

Abstract Ischemia/reperfusion (I/R) is an important inducer of acute kidney injury (AKI), and triggers the generation of reactive oxygen species (ROS) and the expression of matrix metalloproteinase 2 (MMP2), exacerbating kidney damage. Given the immense potential of vitamin E (VitE) as a natural fat-soluble antioxidant in kidney protection, we designed the nanoparticles (NPs) that could dual respond to ROS and MMP2, aiming to accurately deliver VitE to renal injury cells. The NPs utilized Gel-SH as a sensitive receptor for MMP2 and diselenide as a sensitive receptor for ROS, while PEG2k modification enhanced biocompatibility and prevented phagocytosis mediated by the mononuclear phagocyte system. The amphiphilic Gel-SH and diselenide encapsulate the liposoluble VitE and self-assemble into the NPs with a hydrodynamic size of 69.92 nm. Both in vivo and in vitro experiments based on these NPs show good biocompatibility and the ability of target renal injury cells. In vivo kidney I/R injury models and in vitro cell hypoxia/reoxygenation models, the NPs have demonstrated effects in reducing oxidative stress and alleviating AKI. Notably, VitE can preferentially react with peroxyl radical (LOO•) than polyunsaturated fatty acid (PUFA), inhibiting the formation of carbon centered radical (L•), thereby blocking the chain reaction between PUFA and LOO• in ferroptosis. The NPs also inhibit the transition from AKI to chronic kidney disease, with few side effects. Thus, the NPs with dual-responsiveness to MMP2 and ROS for targeted delivery of VitE to renal injury cells exhibit remarkable effects in inhibiting ROS and the chain reactions of ferroptosis, making it a promising therapeutic agent against AKI caused by I/R. Graphical abstract

BACKGROUND: Buqi Huoxue Compounds have significant clinical efficacy in treating ischemic stroke with Qi deficiency and phlegm stasis; however, the exact mechanism of action is not clear. OBJECTIVE: To observe the effect of Buqi Huoxue Compounds on the expression of vascular endothelial growth factor, basic fibroblast growth factor, brain-derived neurotrophic factor and autophagy related protein Beclin1 and p62 in a rat model of cerebral ischemia/reperfusion. METHODS: Forty male Sprague-Dawley rats were randomly divided into sham operation group, model group, Buqi Huoxue Compounds group and autophagy inhibitor group, with 10 rats in each group. In the latter three groups, a rat model of cerebral ischemia/reperfusion injury was established. The Buqi Huoxue Compounds group was intragastrically given Buqi Huoxue Compounds (6.49 g/kg, administered three times a day) 2 hours after reperfusion; the autophagy inhibitor group was intragastrically given Buqi Huoxue Compounds (6.49 g/kg, administered three times a day) 2 hours after reperfusion and intraperitoneally given 3-methyladenine 2 hours before gavage and at days 1-3 of gavage. The sham operation group and model group were given equal amounts of saline by gavage for 7 consecutive days. Neurological function, cerebral infarct volume, brain tissue morphology and expression of vascular endothelial growth factor, basic fibroblast growth factor, brain-derived neurotrophic factor and autophagy-related proteins Beclin1 and p62 in the ischemic cortical region of rats were detected at 24 hours after the final administration. RESULTS AND CONCLUSION: Zea-Longa scoring results showed that the neurological function of rats was severely damaged after modeling and neurological deficit of rats in the Buqi Huoxue Compounds group was less than that in the model group and the autophagy inhibitor group (P < 0.05). TTC staining showed that cerebral infarct foci were observed in the model group, Buqi Huoxue Compounds group, and autophagy inhibitor group, and the cerebral infarct volume in the Buqi Huoxue Compounds group was lower than that in the model group and the autophagy inhibitor group (P < 0.05). The results of hematoxylineosin staining in ischemic brain tissues showed that there were large gaps between nerve cells in the model group and cell arrangement was not neat, and cytoplasmic agglutination and pyknosis were observed. Immunohistochemical staining results showed that vascular endothelial growth factor was mostly expressed in neuronal cells, glial cells and capillary endothelium; basic fibroblast growth factor and brain-derived neurotrophic factor were mostly expressed in neuronal cells and glial cells; and there was no significant difference in the expression of vascular endothelial growth factor, basic fibroblast growth factor, and brain-derived neurotrophic factor among the four groups (P > 0.05). The results of western blot assay showed that compared with the sham operation group, Beclin1 protein expression was decreased (P < 0.05) and p62 protein expression was elevated (P < 0.05) in the model group; compared with the model group, Beclin1 protein expression was increased (P < 0.05) and p62 protein expression was reduced (P < 0.05) in the Buqi Huoxue Compounds group; compared with the Buqi Huoxue Compounds group, Beclin1 protein expression was decreased (P < 0.05) and p62 protein expression was elevated (P < 0.05) in the autophagy inhibitor group. To conclude, Buqi Huoxue Compounds attenuate cerebral ischemia-reperfusion injury in rats by promoting autophagy. [ABSTRACT FROM AUTHOR]

Abstract Background Gasdermin D (GSDMD) mediated pyroptosis plays a significant role in the pathophysiology of myocardial ischemia/reperfusion (I/R) injury. However, the precise mechanisms regulating pyroptosis remain unclear. In the study, we aimed to investigate the underlying mechanism of pyroptosis in myocardial I/R injury. Methods In the present study, we analyzed the effects of USP5 on the RIPK1 kinase activity mediated pyroptosis in vitro after H/R (hypoxia/reoxygenation) and in vivo in a MI/R mouse model. TTC and Evan’s blue dye, Thioflavin S and immunohistochemistry staining were performed in wild-type, RIPK1flox/flox Cdh5-Cre and USP5 deficiency mice. CMEC cells were transfected with si-USP5. HEK293T cells were transfected with USP5 and RIPK1 overexpression plasmid or its mutants. The levels of USP5, RIPK1, Caspase-8, FADD and GSDMD were determined by Western blot. Protein interactions were evaluated by immunoprecipitation. The protein colocalization in cells was monitored using a confocal microscope. Results In this study, our data demonstrate that RIPK1 is essential for limiting cardiac endothelial cell (CMEC) pyroptosis mediated by caspase-8 in response to myocardial I/R. Additionally, we investigate the role of ubiquitin-specific protease 5 (USP5) as a deubiquitinase for RIPK1. Mechanistically, USP5 interacts with RIPK1, leading to its deubiquitination and stabilization. Conclusions These findings offer new insights into the role of USP5 in regulating RIPK1-induced pyroptosis.

Cem Kaya,1 Alparslan Kapisiz,1 Sibel Eryilmaz,1 Ramazan Karabulut,1 Zafer Turkyilmaz,1 Mehmet Arda Inan,2 Gizem Yaz Aydin,3 Kaan Sonmez1 1Departments of Pediatric Surgery, Gazi University Faculty of Medicine, Yenimahalle, Ankara, Turkey; 2Pathology, Gazi University Faculty of Medicine, Yenimahalle, Ankara, Turkey; 3Biochemistry, Gazi University Faculty of Medicine, Yenimahalle, Ankara, TurkeyCorrespondence: Ramazan Karabulut, Department of Pediatric Surgery, Gazi University, Faculty of Medicine, Emniyet Mahallesi, Mevlana Bulvar&inodot;, No. 29, Yenimahalle, Ankara, 06500, Turkey, Tel +90 312 2026210, Fax +90 312 2230528, Email karabulutr@yahoo.com; ramazank@gazi.edu.trBackground: Ischemia-reperfusion (I/R) injury to the testis can lead to organ damage, infertility, and subfertility. The goal of this study was to investigate the effects of fasudil on this devastating condition.Methods: Thirty male Long-Evans rats were divided into five groups: a control group (no torsion), rats administered fasudil (30 mg/kg, no torsion), rats subject to ischemia with no treatment (I) (I/R injury), injured rats that received treatment 1 (T1) (I/R with 30 mg/kg fasudil before detorsion), and injured rats that received treatment 2 (T2) (I/R with 30 mg/kg fasudil after detorsion). Serum levels of TNF-ɑ and IL-6, along with tissue levels of glutathione (GSH), malondialdehyde (MDA), caspase-3, and Johnsen Tubular Biopsy Score (JTBS), were measured.Results: Group I exhibited significantly higher levels of MDA and caspase-3 than all other groups except T2 (p ˂ 0.05). Although the difference was not statistically significant, Group T2 exhibited lower MDA and caspase-3 levels than Group I (p ˃ 0.05). Additionally, Group I displayed significantly higher TNF-ɑ and IL-6 levels, and lower GSH and JTBS values, than the other groups (p ˂ 0.05).Conclusion: Our findings indicate that fasudil protects the testis from I/R injury, particularly when administered early.Keywords: fasudil, testis, ischemia/reperfusion

Selenium is an important element in nutrition and an essential part of several proteins with catalytic and structural properties. Selenium nanoparticles have a higher effect and less toxicity than conventional selenium. The aim of this study was to demonstrate the strong role of nano-selenium in protecting against renal ischemia/reperfusion (I/R) injury in a male rat model. For this purpose, I/R injury was caused by occlusion of the left renal artery for 20 minutes. A total of 54 male Wistar rats were randomly divided into healthy and sham control groups, three healthy experimental groups receiving selenium nanoparticles at doses of 0.25, 0.5 and 1 mg/kg, I/R control group and three groups of I/R receiving selenium nanoparticles at previously mentioned doses (n=6). Thirty days after administration, the animals were euthanized for biochemical and histopathological evaluation and the data were statistically analyzed (p˂0.05). Selenium nanoparticles in I/R groups significantly decreased serum urea and creatinine levels (p˂0.001) and significantly increased the antioxidant parameters of catalase, glutathione peroxidase and superoxide dismutase and significantly decreased the level of malondialdehyde (p˂0.001) and improved renal tissue damage (p˂0.001) in comparison to other groups. This study showed that selenium nanoparticles have protective effects against damage caused by renal ischemic reperfusion, and this protective effect can be due to their antioxidant properties in improving injuries caused by free radicals in the ischemic reperfusion process, thereby reducing oxidative stress and improving renal tissue structure.

Microcirculatory disturbances are complex processes caused by many factors, including abnormal vasomotor responses, decreased blood flow velocity, vascular endothelial cell injury, altered leukocyte and endothelial cell interactions, plasma albumin leakage, microvascular hemorrhage, and thrombosis. These disturbances involve multiple mechanisms and interactions among mechanisms that can include energy metabolism, the mitochondrial respiratory chain, oxidative stress, inflammatory factors, adhesion molecules, the cytoskeleton, vascular endothelial cells, caveolae, cell junctions, the vascular basement membrane, neutrophils, monocytes, and platelets. In clinical practice, aside from drugs that target abnormal vasomotor responses and platelet adhesion, there continues to be a lack of multi-target drugs that can regulate the complex mechanistic links and interactions underlying microcirculatory disturbances. Natural products have demonstrated obvious positive therapeutic effects in treating ischemia/reperfusion (I/R)- and lipopolysaccharide (LPS)-induced microcirculatory disturbances. In recent years, numerous research papers on the improvement of microcirculatory function by natural products have been published in international journals. In 2008 and 2017, the first listed author of this review was invited to publish reviews in the journal of Pharmacology & Therapeutics on the improvement of microcirculatory disturbances and organ injury induced by I/R using Salvia miltiorrhiza ingredients and other natural components of compounded Chinese medicine, respectively. This review systematically summarizes the effects, targets of action, and mechanisms of natural products regarding improving I/R- and LPS-induced microcirculatory disturbances and tissue injury. Based on this summary, scientific proposals are suggested for the discovery of new drugs to improve microcirculatory disturbances in disease.

Abstract Acute kidney injury (AKI) is closely related to lysosomal dysfunction and ferroptosis in renal tubular epithelial cells (TECs), for which effective treatments are urgently needed. Although selenium nanoparticles (SeNPs) have emerged as promising candidates for AKI therapy, their underlying mechanisms have not been fully elucidated. Here, we investigated the effect of SeNPs on hypoxia/reoxygenation (H/R)-induced ferroptosis and lysosomal dysfunction in TECs in vitro and evaluated their efficacy in a murine model of ischemia/reperfusion (I/R)-AKI. We observed that H/R-induced ferroptosis was accompanied by lysosomal Fe2+ accumulation and dysfunction in TECs, which was ameliorated by SeNPs administration. Furthermore, SeNPs protected C57BL/6 mice against I/R-induced inflammation and ferroptosis. Mechanistically, we found that lysosomal Fe2+ accumulation and ferroptosis were associated with the excessive activation of NCOA4-mediated ferritinophagy, a process mitigated by SeNPs through the upregulation of X-box binding protein 1 (XBP1). Downregulation of XBP1 promoted ferritinophagy and partially counteracted the protective effects of SeNPs on ferroptosis inhibition in TECs. Overall, our findings revealed a novel role for SeNPs in modulating ferritinophagy, thereby improving lysosomal function and attenuating ferroptosis of TECs in I/R-AKI. These results provide evidence for the potential application of SeNPs as therapeutic agents for the prevention and treatment of AKI.

Background: Gasdermin D (GSDMD) mediated pyroptosis plays a significant role in the pathophysiology of myocardial ischemia/reperfusion (I/R) injury. However, the precise mechanisms regulating pyroptosis remain unclear. In the study, we aimed to investigate the underlying mechanism of pyroptosis in myocardial I/R injury. Methods: In the present study, we analyzed the effects of USP5 on the RIPK1 kinase activity mediated pyroptosis in vitro after H/R (hypoxia/reoxygenation) and in vivo in a MI/R mouse model. TTC and Evan's blue dye, Thioflavin S and immunohistochemistry staining were performed in wild-type, RIPK1flox/flox Cdh5-Cre and USP5 deficiency mice. CMEC cells were transfected with si-USP5. HEK293T cells were transfected with USP5 and RIPK1 overexpression plasmid or its mutants. The levels of USP5, RIPK1, Caspase-8, FADD and GSDMD were determined by Western blot. Protein interactions were evaluated by immunoprecipitation. The protein colocalization in cells was monitored using a confocal microscope. Results: In this study, our data demonstrate that RIPK1 is essential for limiting cardiac endothelial cell (CMEC) pyroptosis mediated by caspase-8 in response to myocardial I/R. Additionally, we investigate the role of ubiquitin-specific protease 5 (USP5) as a deubiquitinase for RIPK1. Mechanistically, USP5 interacts with RIPK1, leading to its deubiquitination and stabilization. Conclusions: These findings offer new insights into the role of USP5 in regulating RIPK1-induced pyroptosis. [ABSTRACT FROM AUTHOR]

Objective: Chrysin (Chr) is a flavonoid with many biological activities such as antioxidant, anti-inflammatory and antiautophagic. The effects of Chr on autophagy, oxidative stress and inflammation was investigated in rats with kidney ischemia reperfusion (I/R) injury. Material and Method: Fifty male Sprague-Dawley rats were divided into 5 groups: Sham, I/R, Chr25mg/kg+I/R, Chr50mg/kg+I/R and Chr100mg/kg+I/R. The rats except sham group were give different doses of Chr and underwent bilateral kidney ischemia for 45 minutes on the 14th day then reperfusion for 24 hours. BUN, creatinine, oxidative stress parameters and cytokines levels were measured biochemically. Beclin-1 and LC-3II levels in left kidney tissues were determined immunohistochemically. Results: The low and medium doses of Chr decreased BUN, SOD, GSH and TAS, but also increased MDA and TOS levels. Histopathological findings showed a significant decrease in the Chr25mg/kg+I/R and Chr50mg/kg+I/R groups. LC-3II and Beclin-1 immunoreactivity were higher in I/R and Chr100mg/kg+I/R when compared to the other groups. Conclusion: Administration of low and medium doses of Chr was protective against damage via suppressing autophagy. In addition, low and moderate doses of Chr administration before ischemia also protected the tissues against oxidative damage and inflammation, while high-doses of Chr caused damage similar to I/R in the kidney tissue. [ABSTRACT FROM AUTHOR]

We demonstrated that the serum of pregnant rats increases viability of kidney epithelial cells and promotes their proliferation. The intensity of oxidative stress in the kidneys was also reduced during pregnancy, but only in rats that were not exposed to acute ischemic kidney injury. This decrease in oxidative stress was not associated with changes in transmembrane mitochondrial potential, the size of mitochondria, time of opening of mitochondrial permeability transition pore (mPTP), mitochondrial respiration rate, antioxidant activity, or nitric oxide level. [ABSTRACT FROM AUTHOR]

Ischemia/reperfusion (I/R) is inevitable during kidney transplantation and causes acute kidney injury (AKI), which affects immediate outcome and leads to chronic changes such as fibrotic remodeling of the graft. We investigated pro-fibrotic signaling after I/R, focusing on the complement component and receptor C5a/C5aR1 and macrophage/tubule crosstalk. Male Dark Agouti rats were subjected to I/R and their kidneys were harvested 10 min, 6 h, 24 h, 3 days, 5 days and 8 weeks after reperfusion. The development of renal fibrosis was assessed by the detection of Vimentin (VIM), α-smooth muscle actin (α-SMA) and collagen by immunohistochemistry and Sirius Red staining, respectively. The characterization of C5a/C5aR1 activity and C5aR1+ cells was performed by multiplex mRNA analysis, ELISA, immunofluorescence flow cytometry and in situ hybridization in animal models and cell culture analyses. In the cell culture experiments, we focused on macrophage/tubule cell crosstalk in co-culture experiments and mimicked in vivo conditions by hypoxia/reoxygenation and supplementation with C5a. Already 6–24 h after the induction of I/R in the rat model, C5a concentration in the plasma was significantly increased compared to the control. The matrix components VIM and α-SMA peaked on day 5 and declined after 8 weeks, when an increase in collagen was detected using Sirius Red. In contrast to early I/R-induced C5a activation, renal C5ar1 expression was maximal at day 5 and C5 expression increased until week 8, indicating that the renal upregulation of expression is not required for early complement activation. C5aR1 mRNA was detected in neutrophils and macrophages, but not in proximal tubular cells in the injured kidneys. The macrophage/tubular cell co-culture experiments showed that macrophages were mainly responsible for the increased expression of fibrosis-associated genes in tubule cells (ACTA2, VIM, SNAI1, TGFB1 and FGF-2), and hypoxia/reoxygenation had a partially enhancing effect. A direct pro-fibrotic effect of C5a was not observed. Increased TGF-ß levels were dependent on the differentiation of macrophages to the M2 subtype. In conclusion, the early activation of mesenchymal markers in tubular epithelial cells leads to long-term fibrotic remodeling characterized by VIM expression and driven by TGF-ß-dependent macrophage/tubular crosstalk. The chemoattractive properties of complement C5a may contribute to the recruitment of pro-fibrotic macrophages. [ABSTRACT FROM AUTHOR]

Ischemia/reperfusion (I/R) injury following myocardial infarction is a major cause of cardiomyocyte death and impaired cardiac function. Although clinical data show that metformin is effective in repairing cardiac I/R injury, its efficacy is hindered by non-specific targeting during administration, a short half-life, frequent dosing, and potential adverse effects on the liver and kidneys. In recent years, injectable hydrogels have shown substantial potential in overcoming drug delivery challenges and treating myocardial infarction. To this end, we developed a natural polymer hydrogel system comprising methacryloylated chitosan and methacryloylated gelatin modified with polyaniline conductive derivatives. In vitro studies demonstrated that the optimized hydrogel exhibited excellent injectability, biocompatibility, biodegradability, suitable mechanical properties, and electrical conductivity. Incorporating metformin into this hydrogel significantly extended the administration cycle, mitigated mitochondrial damage, decreased abnormal ROS production, and enhanced cardiomyocyte function. Animal experiments indicated that the metformin/hydrogel system reduced arrhythmia incidence, infarct size, and improved cardiac mitochondrial and overall cardiac function, promoting myocardial repair in I/R injury. Overall, the metformin-loaded conductive hydrogel system effectively mitigates mitochondrial oxidative damage and improves cardiomyocyte function, thereby offering a theoretical foundation for the potential application of metformin in cardioprotection. [ABSTRACT FROM AUTHOR]

Acute kidney injury (AKI) is closely related to lysosomal dysfunction and ferroptosis in renal tubular epithelial cells (TECs), for which effective treatments are urgently needed. Although selenium nanoparticles (SeNPs) have emerged as promising candidates for AKI therapy, their underlying mechanisms have not been fully elucidated. Here, we investigated the effect of SeNPs on hypoxia/reoxygenation (H/R)-induced ferroptosis and lysosomal dysfunction in TECs in vitro and evaluated their efficacy in a murine model of ischemia/reperfusion (I/R)-AKI. We observed that H/R-induced ferroptosis was accompanied by lysosomal Fe2+ accumulation and dysfunction in TECs, which was ameliorated by SeNPs administration. Furthermore, SeNPs protected C57BL/6 mice against I/R-induced inflammation and ferroptosis. Mechanistically, we found that lysosomal Fe2+ accumulation and ferroptosis were associated with the excessive activation of NCOA4-mediated ferritinophagy, a process mitigated by SeNPs through the upregulation of X-box binding protein 1 (XBP1). Downregulation of XBP1 promoted ferritinophagy and partially counteracted the protective effects of SeNPs on ferroptosis inhibition in TECs. Overall, our findings revealed a novel role for SeNPs in modulating ferritinophagy, thereby improving lysosomal function and attenuating ferroptosis of TECs in I/R-AKI. These results provide evidence for the potential application of SeNPs as therapeutic agents for the prevention and treatment of AKI. [ABSTRACT FROM AUTHOR]

Objective: To determine the efficacy of mechanical thrombectomy combined with prolonged mild hypothermia compared with conventional treatment in managing acute middle cerebral artery occlusion, and to explore whether extending the duration of hypothermia can improve neurological function. Method: From 2018 to June 2023, a retrospective analysis was conducted on 45 patients with acute middle cerebral artery occlusion treated at the NICU of Suzhou Kowloon Hospital, affiliated with Shanghai Jiao Tong University School of Medicine. After thrombectomy, patients were admitted to the neurological intensive care unit (NICU) for targeted temperature management. Patients were divided into two groups: the mild hypothermia group (34.5-35.9°C) receiving 5-7 days of treatment, and the normothermia group (control group) whose body temperature was kept between 36 and 37.5°C using pharmacological and physical cooling methods. Baseline characteristics and temperature changes were compared between the two groups of patients. The primary outcome was the modified Rankin Scale (mRS) score at 3 month after surgery, and the secondary outcomes were related complications and mortality rate. Prognostic risk factors were investigated using both univariate and multivariate logistic regression analyses. Results: Among 45 patients, 21 underwent prolonged mild hypothermia, and 24 received normothermia, with no significant differences in baseline characteristics between the two groups. The duration of mild hypothermia ranged from 5 to 7 days. The incidence of chills (33.3% vs. 8.3%, p = 0.031) and constipation (57.1% vs. 20.8%, p = 0.028) was significantly higher in the mild hypothermia group compared with the control group. There was no significant difference in mortality rates between the mild hypothermia and the control group (4.76% vs. 8.33%, p = 1.000, OR = 1.75, 95% CI, 0.171-17.949). At 3 month, there was no significant difference in the modified mRS (0-3) score between the mild hypothermia and control groups (52.4% vs. 25%, p = 0.114, OR = 0.477, 95% CI, 0.214-1.066). Infarct core volume was an independent risk factor for adverse neurological outcomes. Conclusion: Prolonged mild hypothermia following mechanical thrombectomy had no severe complications and shows a trend to improve the prognosis of neurological function. The Infarct core volume on CTP was an independent risk factor for predicting neurological function. [ABSTRACT FROM AUTHOR]

Ischemia/reperfusion injury (IRI) represents a significant contributor to morbidity and mortality associated with various clinical conditions, including acute coronary syndrome, stroke, and organ transplantation. During ischemia, a profound hypoxic insult develops, resulting in cellular dysfunction and tissue damage. Paradoxically, reperfusion can exacerbate this injury through the generation of reactive oxygen species and the induction of inflammatory cascades. The extensive clinical sequelae of IRI necessitate the development of therapeutic strategies to mitigate its deleterious effects. This has become a cornerstone of ongoing research efforts in both basic and translational science. This review examines the use of molecular hydrogen for IRI in different organs and explores the underlying mechanisms of its action. Molecular hydrogen is a selective antioxidant with anti-inflammatory, cytoprotective, and signal-modulatory properties. It has been shown to be effective at mitigating IRI in different models, including heart failure, cerebral stroke, transplantation, and surgical interventions. Hydrogen reduces IRI via different mechanisms, like the suppression of oxidative stress and inflammation, the enhancement of ATP production, decreasing calcium overload, regulating cell death, etc. Further research is still needed to integrate the use of molecular hydrogen into clinical practice. [ABSTRACT FROM AUTHOR]

Liver ischemia‐reperfusion (I/R) injury is a common cause of organ failure, developed by a sudden block in the blood and oxygen supply and subsequent restoration. I/R damage is responsible for acute and chronic rejection after organ transplantation, accounting for 10% of early graft failure. The study investigated the therapeutic properties of fangchinoline in liver injury‐induced rats. The rats were divided into three groups: Sham, I/R without pretreatment, and I/R + 10 mg/kg fangchinoline pretreatment. Blood and liver samples were collected for assays, and an in silico docking analysis was conducted to determine fangchinoline's inhibitory effect. The pretreatment with 10 mg/kg of fangchinoline effectively reduced hepatic marker enzymes such as AST, LDH, and ALT in the serum of rats with liver I/R damage. Fangchinoline treatment significantly reduced interleukin‐8 (IL‐8), IL‐6, and tumor necrosis factor‐α (TNF‐α) in I/R‐induced rats, boosting antioxidants and decreasing MDA. Histopathological studies showed liver injury protection, and fangchinoline inhibited TNF‐α and IL‐6 with improved binding affinity. Fangchinoline has hepatoprotective properties by reducing inflammation in rats with liver I/R damage, as demonstrated in the current study. Hence, it can be an effective salutary agent in preventing liver damage caused by I/R. [ABSTRACT FROM AUTHOR]

Acute limb ischemia (ALI) is defined as a sudden reduction in blood flow to a limb, resulting in cessation of blood flow and, therefore, cessation of the delivery of nutrients and oxygen to the tissues of the lower limb. Despite optimal treatment to restore blood flow to ischemic tissues, some patients may suffer from ischemia/reperfusion (I/R) syndrome, the most severe complication after a revascularization procedure used to restore blood flow. There are multiple molecular and cellular factors that are involved in each phase of ALI. This review focuses firstly on molecular and cellular factors of arterial thrombosis, highlighting the role of atherosclerotic plaques, smooth muscle cells (SMCs), and cytokine which may alter key components of the extracellular matrix (ECM). Then, molecular and cellular factors of arterial embolism will be discussed, highlighting the importance of thrombi composition. Molecular and cellular factors of ischemia/reperfusion syndrome are analyzed in depth, highlighting several important mechanisms related to tissue damage, such as inflammation, apoptosis, autophagy, necrosis, and necroptosis. Furthermore, local and general complications of ALI are discussed in the context of molecular alterations. Ultimately, the role of novel biomarkers and targeted therapies is discussed. [ABSTRACT FROM AUTHOR]

AIM: To investigate the effects of ginkgetin on neurological deficit and angiogenesis induced by cerebral ischemia/reperfusion (I/R) and its underlying mechanism. METHODS: Sixty SD rats were randomly allocated into three groups: sham group, I/R model group, and ginkgetin (40 mg/kg) treatment (I/R+ginkgetin) group, with twenty rats in each group. The middle cerebral artery occlusion/reperfusion (MCAO/R) rat model was employed to simulate cerebral I/R, and ginkgetin was administered continuously for 7 days following reperfusion. The cerebral infarction volume was quantified using TTC staining. Neuronal density in the ischemic penumbra was assessed through Nissl staining and immu-nohistochemistry for neuron-specific nuclear protein (NeuN). Microvessel density and angiogenesis in the ischemic penumbra of each group were analyzed using CD31 labeling and BrdU/von willebrand factor (vWF) double labeling immuno-fluorescence staining. Western blot analysis was performed to determine the levels of heat shock protein 70 (HSP70), vascular endothelial growth factor (VEGF), and hypoxia inducible factor-1α (HIF-1α) in the ischemic penumbra. RESULTS : Compared with the I/R model group, the cerebral infarction volume was significantly reduced in ginkgetin treatment group (P<0. 01), the number of neurons, the microvessel density, angiogenesis and the expression levels of HIF-1α, VEGF, and HSP70 in the ischemic penumbra were significantly increased (P<0. 01). CONCLUSION: Ginkgetin exhibits the potential to augment angiogenesis and facilitate neurological function recovery in MCAO rats, while concurrently upregulating the expression of HSP70, VEGF, and HIF-1α within the ischemic penumbra. [ABSTRACT FROM AUTHOR]

Introduction: The comorbidities of ischemic heart disease (IHD) and diabetes mellitus (DM) compromise the protection of the diabetic heart from ischemia/reperfusion (I/R) injury. We hypothesized that manipulation of reperfusion injury salvage kinase (RISK) and survivor activating factor enhancement (SAFE) pathways might protect the diabetic heart, and intervention of these pathways could be a new avenue for potentially protecting the diabetic heart. Methods: All hearts were subjected to 30-min ischemia and 30-min reperfusion. During reperfusion, hearts were exposed to molecules proven to protect the heart from I/R injury. The hemodynamic data were collected using suitable software. The infarct size, troponin T levels, and protein levels in hearts were evaluated. Results: Both cyclosporine-A and nitric oxide donor (SNAP) infusion at reperfusion protected 4-week diabetic hearts from I/R injury. However, 6-week diabetic hearts were protected only by SNAP, but not cyclosporin-A. These treatments significantly (p < 0.05) improved cardiac hemodynamics and decreased infarct size. Conclusions: The administration of SNAP to diabetic hearts protected both 4- and 6-week diabetic hearts; however, cyclosporine-A protected only the 4-week diabetic hearts. The eNOS/GLUT-4 pathway executed the SNAP-mediated cardioprotection. [ABSTRACT FROM AUTHOR]

Currently, the construction of novel biomimetic reduced graphene oxide (RGO)-based nanocomposites to induce neurite sprouting and repair the injured neurons represents a promising strategy in promoting neuronal development or treatment of cerebral anoxia or ischemia. Here, we present an effective method for constructing palladium-reduced graphene oxide (Pd-RGO) nanocomposites by covalently bonding Pd onto RGO surfaces to enhance neurite sprouting of cultured neurons. As described, the Pd-RGO nanocomposites exhibit the required physicochemical features for better biocompatibility without impacting cell viability. Primary neurons cultured on Pd-RGO nanocomposites had significantly increased number and length of neuronal processes, including both axons and dendrites, compared with the control. Western blotting showed that Pd-RGO nanocomposites improved the expression levels of growth associate protein-43 (GAP-43), as well as β-III tubulin, Tau-1, microtubule-associated protein-2 (MAP2), four proteins that are involved in regulating neurite sprouting and outgrowth. Importantly, Pd-RGO significantly promoted neurite length and complexity under oxygen-glucose deprivation/re-oxygenation (OGD/R) conditions, an in vitro cellular model of ischemic brain damage, that closely relates to neuronal GAP-43 expression. Furthermore, using the middle cerebral artery occlusion (MCAO) model in rats, we found Pd-RGO effectively reduced the infarct area, decreased neuronal apoptosis in the brain, and improved the rats’ behavioral outcomes after MCAO. Together, these results indicate the great potential of Pd-RGO nanocomposites as a novel excellent biomimetic material for neural interfacing that shed light on its applications in brain injuries.

Abstract Background L-theanine is a unique non-protein amino acid in tea that is widely used as a safe food additive. We investigated the cardioprotective effects and mechanisms of L-theanine in myocardial ischemia-reperfusion injury (MIRI). Methods The cardioprotective effects and mechanisms of L-theanine and the role of Janus Kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling were investigated in MIRI mice using measures of cardiac function, oxidative stress, and apoptosis. Results Administration of L-theanine (10 mg/kg, once daily) suppressed the MIRI-induced increase in infarct size and serum creatine kinase and lactate dehydrogenase levels, as well as MIRI-induced cardiac apoptosis, as evidenced by an increase in Bcl-2 expression and a decrease in Bax/caspase-3 expression. Administration of L-theanine also decreased the levels of parameters reflecting oxidative stress, such as dihydroethidium, malondialdehyde, and nitric oxide, and increased the levels of parameters reflecting anti-oxidation, such as total antioxidant capacity (T-AOC), glutathione (GSH), and superoxide dismutase (SOD) in ischemic heart tissue. Further analysis showed that L-theanine administration suppressed the MIRI-induced decrease of phospho-JAK2 and phospho-STAT3 in ischemic heart tissue. Inhibition of JAK2 by AG490 (5 mg/kg, once daily) abolished the cardioprotective effect of L-theanine, suggesting that the JAK2/STAT3 signaling pathway may play an essential role in mediating the anti-I/R effect of L-theanine. Conclusions L-theanine administration suppresses cellular apoptosis and oxidative stress in part via the JAK2/STAT3 signaling pathway, thereby attenuating MIRI-induced cardiac injury. L-theanine could be developed as a potential drug to alleviate cardiac damage in MIRI.

Objectives: Ovarian torsion is an important gynaecological emergency because it causes ischemia in ovary. Our aim is to research the effects of Hypericum perforatum on p53, TNF-α, CAT, SOD, GSH, PTEN and is haPI3K/Akt/mTOR pathway in ovarian of rats with ischemia reperfusion (I/R) injury. Materials and Methods: The study included 56 adult female rats which were allocated to 7 groups; control, ischemia, ischemia 300HP, ischemia 600HP, I/R, I/R 300HP and I/R 600HP. H. perforatum was applied to ischemia 300HP, ischemia 600HP, I/R 300HP and I/R 600HP groups at the dose of 300 mg/kg or 600 mg/kg by oral gavage. Collected ovarian tissues were examined by light microscopy, biochemical and real-time PCR techniques. Results: In histological examination, the least degeneration was seen in 600HP group among other groups, apart from control group. TUNEL results showed that apoptosis level of other groups was lower than that of ischemia and I/R groups. CAT and GSH levels of I/R 600HP group increased. The highest level of PTEN and mTOR was found in the ischemia group. The Akt level was lower in I/R and I/R 300HP groups but its level was close to that of control and I/R 600HP groups. TNF-α and p53 mRNA expressions in I/R group were increased. Conclusions: The result of the study showed that H. perforatum (600 mg/kg) had an effect on tissue degeneration, CAT and GSH levels, and also TNF-α and p53 mRNA expressions levels. We suggest that H. perforatum can be considered as an agent to protect against tissues damage during ischemia reperfusion.

Abstract Background Elephant seals exhibit extreme hypoxemic tolerance derived from repetitive hypoxia/reoxygenation episodes they experience during diving bouts. Real-time assessment of the molecular changes underlying protection against hypoxic injury in seals remains restricted by their at-sea inaccessibility. Hence, we developed a proliferative arterial endothelial cell culture model from elephant seals and used RNA-seq, functional assays, and confocal microscopy to assess the molecular response to prolonged hypoxia. Results Seal and human endothelial cells exposed to 1% O2 for up to 6 h respond differently to acute and prolonged hypoxia. Seal cells decouple stabilization of the hypoxia-sensitive transcriptional regulator HIF-1α from angiogenic signaling. Rapid upregulation of genes involved in glutathione (GSH) metabolism supports the maintenance of GSH pools, and intracellular succinate increases in seal but not human cells. High maximal and spare respiratory capacity in seal cells after hypoxia exposure occurs in concert with increasing mitochondrial branch length and independent from major changes in extracellular acidification rate, suggesting that seal cells recover oxidative metabolism without significant glycolytic dependency after hypoxia exposure. Conclusions We found that the glutathione antioxidant system is upregulated in seal endothelial cells during hypoxia, while this system remains static in comparable human cells. Furthermore, we found that in contrast to human cells, hypoxia exposure rapidly activates HIF-1 in seal cells, but this response is decoupled from the canonical angiogenesis pathway. These results highlight the unique mechanisms that confer extraordinary tolerance to limited oxygen availability in a champion diving mammal.

Targeted temperature management (TTM) is standard of care for neonatal hypoxic ischemic encephalopathy (HIE). Prevention of fever, not excluding cooling core body temperature to 33°C, is standard of care for brain injury post cardiac arrest. Although TTM is beneficial, HIE and cardiac arrest still carry significant risk of death and severe disability. Mammalian hibernation is a gold standard of neuroprotective metabolic suppression, that if better understood might make TTM more accessible, improve efficacy of TTM and identify adjunctive therapies to protect and regenerate neurons after hypoxic ischemia brain injury. Hibernating species tolerate cerebral ischemia/reperfusion better than humans and better than other models of cerebral ischemia tolerance. Such tolerance limits risk of transitions into and out of hibernation torpor and suggests that a barrier to translate hibernation torpor may be human vulnerability to these transitions. At the same time, understanding how hibernating mammals protect their brains is an opportunity to identify adjunctive therapies for TTM. Here we summarize what is known about the hemodynamics of hibernation and how the hibernating brain resists injury to identify opportunities to translate these mechanisms for neurocritical care.

Background: L-theanine is a unique non-protein amino acid in tea that is widely used as a safe food additive. We investigated the cardioprotective effects and mechanisms of L-theanine in myocardial ischemia-reperfusion injury (MIRI). Methods: The cardioprotective effects and mechanisms of L-theanine and the role of Janus Kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling were investigated in MIRI mice using measures of cardiac function, oxidative stress, and apoptosis. Results: Administration of L-theanine (10 mg/kg, once daily) suppressed the MIRI-induced increase in infarct size and serum creatine kinase and lactate dehydrogenase levels, as well as MIRI-induced cardiac apoptosis, as evidenced by an increase in Bcl-2 expression and a decrease in Bax/caspase-3 expression. Administration of L-theanine also decreased the levels of parameters reflecting oxidative stress, such as dihydroethidium, malondialdehyde, and nitric oxide, and increased the levels of parameters reflecting anti-oxidation, such as total antioxidant capacity (T-AOC), glutathione (GSH), and superoxide dismutase (SOD) in ischemic heart tissue. Further analysis showed that L-theanine administration suppressed the MIRI-induced decrease of phospho-JAK2 and phospho-STAT3 in ischemic heart tissue. Inhibition of JAK2 by AG490 (5 mg/kg, once daily) abolished the cardioprotective effect of L-theanine, suggesting that the JAK2/STAT3 signaling pathway may play an essential role in mediating the anti-I/R effect of L-theanine. Conclusions: L-theanine administration suppresses cellular apoptosis and oxidative stress in part via the JAK2/STAT3 signaling pathway, thereby attenuating MIRI-induced cardiac injury. L-theanine could be developed as a potential drug to alleviate cardiac damage in MIRI. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to investigate the effect of various astaxanthin (ATX) doses on oxidative damage and autophagy in renal ischemia-reperfusion (I/R) injury-modeled rats. Methods: The rats were divided into five groups: sham group (n=8), I/R (n=8), I/R + 5 mg/kg ATX (n=8), I/R + 10 mg/kg ATX (n=8), and I/R + 25 mg/kg ATX (n=8) groups. ATX was dissolved in 5 mg/kg, 10 mg/kg, and 25 mg/kg olive oil for 7 days and administered to the rats in the experimental group. Sham and I/R groups were also administered ATX solution (olive oil) via oral gavage for 7 days. Renal ischemia reperfusion was induced in all rats except the sham group after the last dose was administered on the 7th day. Reperfusion was conducted for 24 hours after 45 minutes of ischemia. Results: Blood samples were collected, and kidney tissue were incised for biochemical and histological analyses. Superoxide dismutase (SOD) and total antioxidant status (TAS) were significantly lower in the I/R group than in the sham group (p<0.05), whereas malondialdehyde (MDA) and total oxidant status (TOS) values were higher (p<0.05). It was determined that SOD and TAS increased and MDA and TOS decreased in the ATXadministration groups compared with the I/R group, independent of the dose (p<0.05). In the 25 mg/kg ATX + I/R group, Beclin-1 and LC3ß immunoreactivities were significantly higher than those in the other groups (p<0.05). The lowest p62 immunoreactivity was observed in the 25 mg/kg ATX + I/R group. Conclusions: ATX had a protective effect on kidney function and against oxidative damage. Furthermore, high-dose ATX administration protected kidney tissue via autophagy induction in this study. [ABSTRACT FROM AUTHOR]

Renal ischemia/reperfusion is a serious condition that not only causes acute kidney injury, a severe clinical syndrome with high mortality, but is also an inevitable part of kidney transplantation or other kidney surgeries. Alterations of oxygen levels during ischemia/reperfusion, namely hypoxia/reoxygenation, disrupt mitochondrial metabolism and induce structural changes that lead to cell death. A signature mitochondrial phospholipid, cardiolipin, with many vital roles in mitochondrial homeostasis, is one of the key players in hypoxia/reoxygenation-induced mitochondrial damage. In this study, we analyze the effect of hypoxia/reoxygenation on human renal proximal tubule epithelial cell (RPTEC) cardiolipins, as well as their metabolism and mitochondrial functions. RPTEC cells were placed in a hypoxic chamber with a 2% oxygen atmosphere for 24 h to induce hypoxia; then, they were replaced back into regular growth conditions for 24 h of reoxygenation. Surprisingly, after 24 h, hypoxia cardiolipin levels substantially increased and remained higher than control levels after 24 h of reoxygenation. This was explained by significantly elevated levels of cardiolipin synthase and lysocardiolipin acyltransferase 1 (LCLAT1) gene expression and protein levels. Meanwhile, hypoxia/reoxygenation decreased ADP-dependent mitochondrial respiration rates and oxidative phosphorylation capacity and increased reactive oxygen species generation. Our findings suggest that hypoxia/reoxygenation induces cardiolipin remodeling in response to reduced mitochondrial oxidative phosphorylation in a way that protects mitochondrial function. [ABSTRACT FROM AUTHOR]

Objective The aim of the study is to investigate the therapeutic effects of astaxanthin (AST) and resveratrol (RVT) on multiorgan damage in an animal model of the supraceliac aortic ischemia-reperfusion (I/R). Methods In this study, 28 rats (n = 7/group), 200 to 250 g in weight, were randomized to four groups (1: Sham, 2: Control + I/R, 3: AST + I/R, and 4: RVT + I/R). Following the abdominal incision, aortic dissection was performed in the sham group without injury. Other groups underwent I/R injury via supraceliac aortic clamping (20 minutes) and reperfusion. The rats were administered olive oil (3 mL/kg) orally for 2 weeks before and 1 week after the laparotomy. Additionally, oral AST (10 mg/kg) or RVT (50 mg/kg) was given to the study groups. All rats were sacrificed on the 3rd week of the experiment after blood samples were taken for analysis. Multiple rat tissues were removed. Results We found that RVT increased total antioxidant status (TAS) and superoxide dismutase (SOD) levels, and decreased total oxidant status (TOS), oxidative stress index (OSI), myeloperoxidase (MPO), and malondialdehyde (MDA) levels, while AST increased the levels of TAS, decreased TNF-α, MDA, TOS, and OSI (p <0.05). Pathological investigations of the rat tissues revealed that both AST and RVT ameliorated tissue damage and apoptosis. Conclusion Our study suggests that AST and RVT might show therapeutic effects against oxidative tissue damage and apoptosis in an animal model of aortic I/R. Further studies are required. Key Points Major congenital heart diseases are at high risk of multiorgan damage. Re-establishment of blood flow may result in ischemia-reperfusion (I/R) injury. Astaxanthin and resveratrol may have therapeutic effects against I/R injury. [ABSTRACT FROM AUTHOR]

Augmenting the natural melanocortin pathway in mouse eyes with uveitis or diabetes protects the retinas from degeneration. The retinal cells are protected from oxidative and apoptotic signals of death. Therefore, we investigated the effects of a therapeutic application of the melanocortin alpha-melanocyte-stimulating hormone (α-MSH) on an ischemia and reperfusion (I/R) model of retinal degenerative disease. Eyes were subjected to an I/R procedure and were treated with α-MSH. Retinal sections were histopathologically scored. Also, the retinal sections were immunostained for viable ganglion cells, activated Muller cells, microglial cells, and apoptosis. The I/R caused retinal deformation and ganglion cell loss that was significantly reduced in I/R eyes treated with α-MSH. While α-MSH treatment marginally reduced the number of GFAP-positive Muller cells, it significantly suppressed the density of Iba1-positive microglial cells in the I/R retinas. Within one hour after I/R, there was apoptosis in the ganglion cell layer, and by 48 h, there was apoptosis in all layers of the neuroretina. The α-MSH treatment significantly reduced and delayed the onset of apoptosis in the retinas of I/R eyes. The results demonstrate that therapeutically augmenting the melanocortin pathways preserves retinal structure and cell survival in eyes with progressive neuroretinal degenerative disease. [ABSTRACT FROM AUTHOR]

Ligusticum chuanxiong Hort (LC) is used in traditional medicine throughout Southeast Asia as a cardiovascular protective herb, antioxidant, vasorelaxant, and anti-inflammatory. To demonstrate the protective mechanisms of LC on hypoxia/reoxygenation (HR) induced injury in H9c2 cardiomyoblasts, intracellular reactive oxygen species (ROS) content was measured using dichlorodihydrofluorescein diacetate. The cardioprotective effects of LC ethanolic (E) and water (W) extracts were measured by the MTT assay. Changes in cell and nuclear morphology were observed under a phase-contrast and a fluorescent microscope. The mitochondrial membrane potential (MMP) was detected by Rhodamine123 staining. The expressions of pERK1/2, ERK1/2, and Bcl-2 were determined by immunoblotting. LCE and LCW extracts caused no cytotoxicity or ROS generation to H9c2 cardiomyoblasts. The incubation of LCE or LCW during hypoxia increased cell survival (p < 0.05) compared to HR without the extracts. HR-induced cells demonstrated cellular atrophy, cell membrane shrinkage, and DNA condensation. Healthy cells were found in the control, LCE and LCW-treated HR-induced cells. LC restored the reduction of MMP, while LCE and LCW increased the pERK/ERK ratio (p < 0.001). Meanwhile, LCW increased Bcl-2 expression (p < 0.05). LC extracts effectively protected H9c2 cardiomyoblasts from injury caused by HR exposure, suggesting a beneficial use of LC in alleviating damaged cardiomyoblasts from acute ischemia. [ABSTRACT FROM AUTHOR]

The high mortality rate among patients with acute myocardial infarction (AMI) is one of the main problems of modern cardiology. It is quite obvious that there is an urgent need to create more effective drugs for the treatment of AMI than those currently used in the clinic. Such drugs could be enzyme-resistant peptide analogs of glucagon-like peptide-1 (GLP-1). GLP-1 receptor (GLP1R) agonists can prevent ischemia/reperfusion (I/R) cardiac injury. In addition, chronic administration of GLP1R agonists can alleviate the development of adverse cardiac remodeling in myocardial infarction, hypertension, and diabetes mellitus. GLP1R agonists can protect the heart against oxidative stress and reduce proinflammatory cytokine (IL-1β, TNF-α, IL-6, and MCP-1) expression in the myocardium. GLP1R stimulation inhibits apoptosis, necroptosis, pyroptosis, and ferroptosis of cardiomyocytes. The activation of the GLP1R augments autophagy and mitophagy in the myocardium. GLP1R agonists downregulate reactive species generation through the activation of Epac and the GLP1R/PI3K/Akt/survivin pathway. The GLP1R, kinases (PKCε, PKA, Akt, AMPK, PI3K, ERK1/2, mTOR, GSK-3β, PKG, MEK1/2, and MKK3), enzymes (HO-1 and eNOS), transcription factors (STAT3, CREB, Nrf2, and FoxO3), KATP channel opening, and MPT pore closing are involved in the cardioprotective effect of GLP1R agonists. [ABSTRACT FROM AUTHOR]

Background and Objectives: Erdosteine (Erd) is an antioxidant and anti-inflammatory drug. Vitamin B has been reported to exert anti-inflammatory and antioxidant effects. In this study, we investigated the effect of erdosteine and vitamin B complex on a liver ischemia/reperfusion (I/R) model. Materials and Methods: Thirty-two Wistar Albino male rats weighing 350–400 g were used. The animals were randomly selected and divided into four groups. The groups are as follows: first group (Sham), second group (I/R), third group (I/R + vit B), and fourth group (I/R + vit B + Erd). Rats were subjected to 45 min of hepatic ischemia, followed by a 45 min reperfusion period in the I/R and Vitamin B + Erd groups. An amount of 150 mg/kg/day of erdosteine was given orally for 2 days, and 0.05 mL/kg of i.p. vitamin B complex was given 30 min before the reperfusion. Serum biochemical parameters were measured. Serum Total Antioxidant Status (TAS) and Total Oxidant Status (TOS) were measured, and the Oxidative Stress Index (OSI) was calculated. Hepatic tissue samples were taken for the evaluation of histopathological features. Results: In terms of all histopathological parameters, there were significant differences in the I/R + vit B group and I/R + vit B + Erd group compared with the I/R group (p < 0.01). In terms of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), TNF-alpha, and IL-6 levels, there were significant differences between the I/R group and treatment groups (p < 0.01). The lowest TOS and OSI levels were obtained in the treatment groups, and these groups had statistically significantly higher TAS levels compared with the sham and I/R groups (p < 0.01). Conclusions: As a preliminary experimental study, our study suggests that these agents may have potential diagnostic and therapeutic implications for both ischemic conditions and liver-related diseases. These results suggest that the combination of vit B + Erd may be used to protect against the devastating effects of I/R injury. Our study needs to be confirmed by clinical studies with large participation. [ABSTRACT FROM AUTHOR]

Background: Elephant seals exhibit extreme hypoxemic tolerance derived from repetitive hypoxia/reoxygenation episodes they experience during diving bouts. Real-time assessment of the molecular changes underlying protection against hypoxic injury in seals remains restricted by their at-sea inaccessibility. Hence, we developed a proliferative arterial endothelial cell culture model from elephant seals and used RNA-seq, functional assays, and confocal microscopy to assess the molecular response to prolonged hypoxia. Results: Seal and human endothelial cells exposed to 1% O2 for up to 6 h respond differently to acute and prolonged hypoxia. Seal cells decouple stabilization of the hypoxia-sensitive transcriptional regulator HIF-1α from angiogenic signaling. Rapid upregulation of genes involved in glutathione (GSH) metabolism supports the maintenance of GSH pools, and intracellular succinate increases in seal but not human cells. High maximal and spare respiratory capacity in seal cells after hypoxia exposure occurs in concert with increasing mitochondrial branch length and independent from major changes in extracellular acidification rate, suggesting that seal cells recover oxidative metabolism without significant glycolytic dependency after hypoxia exposure. Conclusions: We found that the glutathione antioxidant system is upregulated in seal endothelial cells during hypoxia, while this system remains static in comparable human cells. Furthermore, we found that in contrast to human cells, hypoxia exposure rapidly activates HIF-1 in seal cells, but this response is decoupled from the canonical angiogenesis pathway. These results highlight the unique mechanisms that confer extraordinary tolerance to limited oxygen availability in a champion diving mammal. [ABSTRACT FROM AUTHOR]

We have recently demonstrated that Jumonji domain‐containing protein D3 (JMJD3), a histone demethylase of histone H3 on lysine 27 (H3K27me3), is protective against renal fibrosis, but its role in acute kidney injury (AKI) remains unexplored. Here, we report that JMJD3 activity is required for renal protection and regeneration in murine models of AKI induced by ischemia/reperfusion (I/R) and folic acid (FA). Injury to the kidney upregulated JMJD3 expression and induced expression of H3K27me3, which was coincident with renal dysfunction, renal tubular cell injury/apoptosis, and proliferation. Blocking JMJD3 activity by GSKJ4 led to worsening renal dysfunction and pathological changes by aggravating tubular epithelial cell injury and apoptosis in both murine models of AKI. JMJD3 inhibition by GSKJ4 also reduced renal tubular cell proliferation and suppressed expression of cyclin E and phosphorylation of CDK2, but increased p21 expression in the injured kidney. Furthermore, inactivation of JMJD3 enhanced I/R‐ or FA‐induced expression of TGF‐β1, vimentin, and Snail, phosphorylation of Smad3, STAT3, and NF‐κB, and increased renal infiltration by F4/80 (+) macrophages. Finally, GSKJ4 treatment caused further downregulation of Klotho, BMP‐7, Smad7, and E‐cadherin, all of which are associated with renal protection and have anti‐fibrotic effects. Therefore, these data provide strong evidence that JMJD3 activation contributes to renal tubular epithelial cell survival and regeneration after AKI. [ABSTRACT FROM AUTHOR]

Objectives: Ovarian torsion is an important gynaecological emergency because it causes ischemia in ovary. Our aim is to research the effects of Hypericum perforatum on p53, TNF-α, CAT, SOD, GSH, PTEN and is haPI3K/Akt/mTOR pathway in ovarian of rats with ischemia reperfusion (I/R) injury. Materials and Methods: The study included 56 adult female rats which were allocated to 7 groups; control, ischemia, ischemia 300HP, ischemia 600HP, I/R, I/R 300HP and I/R 600HP. H. perforatum was applied to ischemia 300HP, ischemia 600HP, I/R 300HP and I/R 600HP groups at the dose of 300 mg/kg or 600 mg/kg by oral gavage. Collected ovarian tissues were examined by light microscopy, biochemical and real-time PCR techniques. Results: In histological examination, the least degeneration was seen in 600HP group among other groups, apart from control group. TUNEL results showed that apoptosis level of other groups was lower than that of ischemia and I/R groups. CAT and GSH levels of I/R 600HP group increased. The highest level of PTEN and mTOR was found in the ischemia group. The Akt level was lower in I/R and I/R 300HP groups but its level was close to that of control and I/R 600HP groups. TNF-α and p53 mRNA expressions in I/R group were increased. Conclusions: The result of the study showed that H. perforatum (600 mg/kg) had an effect on tissue degeneration, CAT and GSH levels, and also TNF-α and p53 mRNA expressions levels. We suggest that H. perforatum can be considered as an agent to protect against tissues damage during ischemia reperfusion. [ABSTRACT FROM AUTHOR]

Aim: Mitochondrial dysfunction, a characteristic pathological feature of renal Ischemic/reperfusion injury (I/RI), predisposes tubular epithelial cells to maintain an inflammatory microenvironment, however, the exact mechanisms through which mitochondrial dysfunction modulates the induction of tubular injury remains incompletely understood. Methods: ESI‐QTRAP‐MS/MS approach was used to characterize the targeted metabolic profiling of kidney with I/RI. Tubule injury, mitochondrial dysfunction, and fumarate level were evaluated using qPCR, transmission electron microscopy, ELISA, and immunohistochemistry. Results: We demonstrated that tubule injury occurred at the phase of reperfusion in murine model of I/RI. Meanwhile, enhanced glycolysis and mitochondrial dysfunction were found to be associated with tubule injury. Further, we found that tubular fumarate, which resulted from fumarate hydratase deficiency and released from dysfunctional mitochondria, promoted tubular injury. Mechanistically, fumarate induced tubular injury by causing disturbance of glutathione (GSH) hemostasis. Suppression of GSH with buthionine sulphoximine administration could deteriorate the fumarate inhibition‐mediated tubule injury recovery. Reactive oxygen species/NF‐κB signaling activation played a vital role in fumarate‐mediated tubule injury. Conclusion: Our studies demonstrated that the mitochondrial‐derived fumarate promotes tubular epithelial cell injury in renal I/RI. Blockade of fumarate‐mediated ROS/NF‐κB signaling activation may serve as a novel therapeutic approach to ameliorate hypoxic tubule injury. [ABSTRACT FROM AUTHOR]