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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.

Purpose: The role of platelets during myocardial ischemia/reperfusion (I/R) is ambivalent. They contribute to injury but also to cardioprotection. Repeated blood flow restriction and reperfusion in a tissue/organ remote from the heart (remote ischemic conditioning, RIC) reduce myocardial I/R injury and attenuate platelet activation. Whether or not platelets mediate RIC's cardioprotective signal is currently unclear., Methods and Results: Venous blood from healthy volunteers (without or with pretreatment of 500/1000 mg aspirin or 180 mg ticagrelor orally, 2-3 h before the study, n = 18 each) was collected before and after RIC (3 × 5 min blood pressure cuff inflation at 200 mmHg on the left upper arm/5 min deflation). Washed platelets were isolated. Platelet-poor plasma was used to prepare plasma-dialysates. Platelets (25 × 10 3 /µL) or plasma-dialysates (1:10) prepared before and after RIC from untreated versus aspirin- or ticagrelor-pretreated volunteers, respectively, were infused into isolated buffer-perfused rat hearts. Hearts were subjected to global 30 min/120 min I/R. Infarct size was stained. Infarct size was less with infusion of platelets/plasma-dialysate after RIC (18 ± 7%/23 ± 9% of ventricular mass) than with platelets/plasma-dialysate before RIC (34 ± 7%/33 ± 8%). Aspirin pretreatment abrogated the transfer of RIC's cardioprotection by platelets (after/before RIC, 34 ± 7%/33 ± 7%) but only attenuated that by plasma-dialysate (after/before RIC, 26 ± 8%/32 ± 5%). Ticagrelor pretreatment induced an in vivo formation of cardioprotective factor(s) per se (platelets/plasma-dialysate before RIC, 26 ± 7%/26 ± 7%) but did not impact on RIC's cardioprotection by platelets/plasma-dialysate (20 ± 7%/21 ± 5%)., Conclusion: Platelets serve as carriers for RIC's cardioprotective signal through an aspirin-sensitive and thus cyclooxygenase-dependent mechanism. The P2Y 12 inhibitor ticagrelor per se induces a humoral cardioprotective signal., (© 2022. The Author(s).)

S-Allylcysteine (SAC) is an extensively studied natural product which has been proven to confer cardioprotection. This potentiates SAC into many clinical relevance possibilities, hence, the use of it ought to be optimally elucidated. To further confirm this, an ischemia/reperfusion model has been used to determine SAC at 10 mM and 50 mM on cardiac function, cardiac marker, and mitochondrial permeability. Using Langendorff setup, 24 adult male Wistar rats' hearts were isolated to be perfused with Kreb-Henseleit buffer throughout the ischemia/reperfusion method. After 20 min of stabilization, global ischemia was induced by turning off the perfusion for 35 min followed by 60 min of reperfusion with either Kreb-Henseleit buffer or SAC with the dose of 10 mM or 50 mM. The cardiac function was assessed and coronary effluent was collected at different timepoints throughout the experiment for lactate dehydrogenase (LDH) measurement. The harvested hearts were then used to measure glutathione while isolated mitochondria for mPTP analysis. SAC-reperfused hearts were shown to prevent the aggravation of cardiac function after I/R induction. It also dose-dependently upregulated glutathione reductase and glutathione level and these were also accompanied by significant reduction of LDH leakage and preserved mitochondrial permeability. Altogether, SAC dose-dependently was able to recover the post-ischemic cardiac function deterioration alongside with improvement of glutathione metabolism and mitochondrial preservation. These findings highly suggest that SAC when sufficiently supplied to the heart would be able to prevent the deleterious complications after the ischemic insult., (Copyright © 2021 Elsevier Inc. All rights reserved.)

This research is the first to use β-sitosterol on myocardial and renal tissues in renal ischemia/reperfusion (IR) damage. Female Wistar rats were randomly divided into three groups: control (sham), renal IR (50 min ischemia - 3 h reperfusion), and renal IR + 150 mg/kg/p.o. β-sitosterol (the rats were treated with β-sitosterol orally once 1 h before the IR procedure). β-Sitosterol pretreatment caused an increase in superoxide dismutase and glutathione activities and a decrease in malondialdehyde levels in the kidney and heart. Moreover, it alleviated histopathological changes and downregulated the levels of tumor necrosis factor-alpha and interleukin-6 and upregulated the levels of endothelial nitric oxide synthase. As conclusion, the potential of β-sitosterol for renal and cardiac necrosis and apoptosis appears to act by limiting inflammatory response and oxidative stress. Thus, the potential of this compound is noteworthy and may serve as a potential therapeutic in the treatment of acute organ damages due to renal IR.

Retinal ischemia leads to an early severe damage of the retina and thus plays an important role in eye diseases such as angle-closure glaucoma or retinal vascular occlusion. In retinal diseases, there is common sense about the affection of the optic nerve by ischemic injury. However, the exact dynamic processes of this optic nerve degeneration are mainly unclear. In this study, retinal ischemia was induced in one eye of Brown-Norway rats by raising the intraocular pressure 60 min to 140 mmHg followed by natural reperfusion. Optic nerves were analyzed at six different points in time: 2, 6, 12, and 24 h as well as 3 and 7 days after ischemic injury. Cell infiltration and moreover signs of tissue demyelination and dissolution were noticed in optic nerves 7 days after ischemia (hematoxylin & eosin: p < 0.001, luxol fast blue: p = 0.04). Although microglial activation was verified already from 12 h on after ischemia (p = 0.030), the beginning of a structural degeneration of the neurofilament was seen at 3 days (p = 0.02). Interestingly, proliferative microglia were present later on (7 days: p = 0.017). At this point, the number of total microglia was also increased in ischemic nerves (p = 0.003). Concluding, our data indicate that not only retinal tissue is affected by an ischemia, the optic nerve also demonstrates progressive damage. Interestingly, a microglia activation was noted days before structural damage became visible., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Apoptosis, reactive oxidative stress (ROS) and inflammation act as the pivotal pathogenesis of myocardial ischemia/reperfusion (I/R) injury (MIRI). Our prior study and other investigation have demonstrated the participations of src homology 2 (SH2) B adaptor protein 1 (SH2B1) in ischemic injury and cardiac hypertrophy; whereas, the involvements of SH2B1 in MIRI and underlying mechanisms are completely unknown., Method: In present study, MIRI model in vivo was induced by 30 min of ligation of LAD coronary artery and 24 h of reperfusion, and primary cultured cardiomyocytes were challenged with 2 h of hypoxia followed by 4 h of reoxygenation (H/R) to mimic MIRI in vitro. Adenovirus encoding for SH2B1 or GFP were pre-transfected into myocardium prior to MIRI both in vivo and in vitro. The myocardial damage, cardiac function, apoptosis, ROS and inflammation were evaluated systematically. Immunofluorescence staining and western blotting were alternatively performed to detect protein expression., Results: The results exhibited that H/R or I/R significantly reduced SH2B1 in cardiomyocytes, followed by impaired cell survival and function, which were strongly reversed after the adenovirus-mediated SH2B1 up-regulation. Meanwhile, I/R- and H/R-elevated inflammation, apoptosis and ROS were also alleviated by SH2B1 up-regulation. A mechanistic study suggested that the protective contributions of SH2B1 on H/R-suffered cardiomyocytes were based on the activation of the PI3K/AKT pathway. The abolishment of the PI3K/AKT via a pharmacological inhibitor (LY294002) repressed anti-H/R capabilities of SH2B1., Conclusion: Therefore, SH2B1 prevents cardiomyocytes from inflammation, apoptosis and ROS in MIRI partially through the PI3K/AKT-dependent avenues. It may provide a novel therapeutic target for the treatment of MIRI., Competing Interests: Declaration of competing interest The authors declare that there is no duality of interest associated with this manuscript., (Copyright © 2019. Published by Elsevier B.V.)

In a recent study, we identified a fucosylated damage-associated ligand exposed by ischemia on renal tubule epithelial cells, which after recognition by collectin-11 (CL-11 or collectin kidney 1 (CL-K1)), initiates complement activation and acute kidney injury. We exploited the ability to increase the local tissue concentration of free l-fucose following systemic administration, in order to block ligand binding by local CL-11 and prevent complement activation. We achieved a thirty-five-fold increase in the intrarenal concentration of l-fucose following an IP bolus given before the ischemia induction procedure - a concentration found to significantly block in vitro binding of CL-11 on hypoxia-stressed renal tubule cells. At this l-fucose dose, complement activation and acute post-ischemic kidney injury are prevented, with additional protection achieved by a second bolus after the induction procedure. CL-11 -/- mice gained no additional protection from l-fucose administration, indicating that the mechanism of l-fucose therapy was largely CL-11-dependent. The hypothesis is that a high dose of l-fucose delivered to the kidney obstructs the carbohydrate recognition site on CL-11 thereby reducing complement-mediated damage following ischemic insult. Further work will examine the utility in preventing post-ischemic injury during renal transplantation, where acute kidney injury is known to correlate with poor graft survival., (© 2019 The Authors. The FASEB Journal published by Wiley Periodicals, Inc. on behalf of Federation of American Societies for Experimental Biology.)

Background: It has been reported that n-butanol extract of Potentilla anserina L (NP) had protective effect against acute myocardial ischemia/reperfusion (I/R) injury in mice. Because of limited phytochemical study on NP, its bioactive compounds and underlying protective mechanisms are largely unclear., Purpose: The purpose of this study was to investigate the major bioactive compounds and possible mechanism for the cardioprotective effect of NP on rat with I/R injury., Methods: We analyzed the phytochemical isolation of NP and identified the structure of compounds, which was elucidated by a combination of spectroscopic analyses. An I/R model was established by I-30 min/R-2 h in Sprage-Dawley rats. The rats were given intragastric administration of NP (49.3, 98.6, and 197.2 mg•kg -1 ) continuously for 10 days before I/R operation. The morphological changes and apoptosis of cardiomyocytes were observed by H&E staining, Transmission electron microscope and TUNEL staining respectively. The activities or contents of catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) in plasma were detected. Apoptosis related factors were also measured by RT-PCR and western blot. In order to discover the underlying mechanism of NP on I/R, we performed proteomic analysis using two-dimensional gel electrophoresis (2D-DIGE) and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF/MS) to describe differential proteins expression. Potential target protein resulted from 2D-DIGE coupled to MALDI-TOF/MS analysis were further confirmed by immunohistochemical staining, RT-PCR, and western blot., Results: We isolated and identified 14 compounds, of which 7 compounds belong to triterpenes. Rats pretreated with NP showed a significant increase on the activities of GSH, SOD and CAT, and remarkable decrease on the content of MDA. NP significantly inhibited the apoptosis of cardiomyocyte and decreased the expression of Cyt C and cleaved-caspase-3. Proteomic analysis revealed that alpha B-crystallin (CryAB) might participate in the NP protective effect against I/R. NP enhanced the level of pCryAB Ser59, whereas the expression of CryAB was decreased., Conclusion: NP was showed to alleviate I/R injury and inhibit myocardial apoptosis, which might be associated with reduction on oxidative stress and apoptosis. CryAB as a possible target involved in the NP protective effect. This study supplied valuable information to develop novel cardioprotective agents from NP extract., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Background: A correlation between the level of asymmetric dimethylarginine (ADMA) - the inhibitor of the nitric oxide (NO) synthesis - and the liver function and survival after a liver transplantation has been reported., Objectives: The aim of this study was to evaluate the effect of sitagliptin -the inhibitor of dipeptidyl peptidase-4 (DPP-4) - on the NO-ADMA-dimethylarginine dimethylaminohydrolase (DDAH) pathway in rat livers subjected to ischemia/reperfusion (IR)., Material and Methods: The rats received sitagliptin (5 mg/kg, per os - p.o.) (groups: S - livers not subjected to IR procedure, and SIR - livers subjected to IR procedure) or a saline solution (groups: C - livers not subjected to IR procedure, and CIR - livers subjected to IR procedure) for 14 days; following this, livers in the SIR and CIR groups were subjected to ischemia (60 min) and reperfusion (24 h). Aminotransferases were measured before the surgery; additionally, the arginine (ARG), ADMA and symmetric dimethylarginine (SDMA) levels were estimated just before ischemia and during reperfusion (at 0.5, 4 and 24 h). After IR, citrulline, the DDAH activity, mRNA for type 1 DDAH (DDAH1), and arginine methyltransferase type 1 (PRMT1) were determined., Results: The increase in the initial level of ARG/ADMA0 (A/A) ratio in group S compared to group C verged on statistical significance. At 0.5 and 4 h of reperfusion, the highest concentration of ADMA was found in group CIR. At those time points, the ARG level and the A/A ratio were decreased in groups CIR and SIR as compared to groups C and S, respectively. The alanine transaminase (ALT) activity was lower in the sitagliptin-treated group than in the non-treated one. The DDAH and citrulline levels were reduced in group CIR as compared to group C, but were greater in group SIR as compared to group S. The PRMT1 mRNA expression was higher in groups CIR and SIR, compared to groups C and S, respectively., Conclusions: The increased A/A ratio suggests a protective effect of sitagliptin on livers not subjected to IR. Changes in the DDAH activity and the PRMT1 mRNA expression also imply the protective activity of sitagliptin during IR.

Renal iron recycling preserves filtered iron from urinary excretion. However, it remains debated whether ferroportin (FPN), the only known iron exporter, is functionally involved in renal iron recycling and whether renal iron recycling is required for systemic iron homeostasis. We deleted FPN in whole nephrons by use of a Nestin-Cre and in the distal nephrons and collecting ducts, using a Ksp-Cre, and investigated its impacts on renal iron recycling and systemic iron homeostasis. FPN deletion by Nestin-Cre, but not by Ksp-Cre, caused excess iron retention and increased ferritin heavy chain (FTH1) specifically in the proximal tubules and resulted in the reduction of serum and hepatic iron. The systemic iron redistribution was aggravated, resulting in anemia and the marked downregulation of hepatic hepcidin in elderly FPN knockout (KO)/Nestin-Cre mice. Similarly, in iron-deficient FPN KO/Nestin-Cre mice, the renal iron retention worsened anemia with the activation of the erythropoietin-erythroferrone-hepcidin pathway and the downregulation of hepatic hepcidin. Hence, FPN likely located at the basolateral membrane of the proximal tubules to export iron into the circulation and was required for renal iron recycling and systemic iron homeostasis particularly in elderly and iron-deficient mice. Moreover, FPN deletion in the proximal tubules alleviated ischemic acute kidney injury, possibly by upregulating FTH1 to limit catalytic iron and by priming antioxidant mechanisms, indicating that FPN could be deleterious in the pathophysiology of ischemic acute kidney injury (AKI) and thus may be a potential target for the prevention and mitigation of ischemic AKI.

Retinal ischemia is an important factor in several eye disorders. To investigate the impact of VEGF inhibitors, as a therapeutic option, we studied these in a retinal ischemia animal model. Therefore, animals received bevacizumab or ranibizumab intravitreally one day after ischemia induction. Via electroretinography, a significant decrease in a- and b-wave amplitudes was detected fourteen days after ischemia, but they were reduced to a lesser extent in the ranibizumab group. Ischemic and bevacizumab retinae displayed fewer retinal ganglion cells (RGCs), while no significant cell loss was noted in the ranibizumab group. Apoptosis was reduced after therapy. More autophagocytotic cells were observed in ischemic and bevacizumab eyes, but not in ranibizumab eyes. Additionally, more microglia, as well as active ones, were revealed in all ischemic groups, but the increase was less prominent under ranibizumab treatment. Fewer cone bipolar cells were detected in ischemic eyes, in contrast to bevacizumab and ranibizumab-treated ones. Our results demonstrate a reduced apoptosis and autophagocytosis rate after ranibizumab treatment. Furthermore, a certain protection was seen regarding functionality, RGC, and bipolar cell availability, as well as microglia activation by ranibizumab treatment after ischemic damage. Thus, ranibizumab could be an option for treatment of retinal ischemic injury.

Mitochondria are a major target in hypoxic/ischemic injury. Mitochondrial impairment increases with age leading to dysregulation of molecular pathways linked to mitochondria. The perturbation of mitochondrial homeostasis and cellular energetics worsens outcome following hypoxic-ischemic insults in elderly individuals. In response to acute injury conditions, cellular machinery relies on rapid adaptations by modulating posttranslational modifications. Therefore, post-translational regulation of molecular mediators such as hypoxia-inducible factor 1α (HIF-1α), peroxisome proliferator-activated receptor γ coactivator α (PGC-1α), c-MYC, SIRT1 and AMPK play a critical role in the control of the glycolytic-mitochondrial energy axis in response to hypoxic-ischemic conditions. The deficiency of oxygen and nutrients leads to decreased energetic reliance on mitochondria, promoting glycolysis. The combination of pseudohypoxia, declining autophagy, and dysregulation of stress responses with aging adds to impaired host response to hypoxic-ischemic injury. Furthermore, intermitochondrial signal propagation and tissue wide oscillations in mitochondrial metabolism in response to oxidative stress are emerging as vital to cellular energetics. Recently reported intercellular transport of mitochondria through tunneling nanotubes also play a role in the response to and treatments for ischemic injury. In this review we attempt to provide an overview of some of the molecular mechanisms and potential therapies involved in the alteration of cellular energetics with aging and injury with a neurobiological perspective., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

We have found that Fas/FasL-mediated "extrinsic" pathway promoted cell apoptosis induced by renal ischemic injury. This study is to elucidate the upstream mechanism regulating FasL-induced extrinsic pathway during renal ischemia/reperfusion. Results demonstrated that when SIRT2 was activated by renal ischemia/reperfusion, activated SIRT2 could bind to and deacetylate FOXO3a, promoting FOXO3a nuclear translocation which resulted in an increase of nuclear FOXO3a along with FasL expression and activation of caspase8 and caspase3, triggering cell apoptosis during renal ischemia/reperfusion. The administration of SIRT2 inhibitor AGK2 prior to renal ischemia decreased significantly the number of apoptotic renal tubular cells and alleviated ultrastructure injury. These results indicate that inhibition of FOXO3a deacetylation might be a promising therapeutic approach for renal ischemia /reperfusion injury.

Sulfur dioxide (SO2) is naturally synthesized by glutamate-oxaloacetate transaminase (GOT) from L-cysteine in mammalian cells. We found that SO2 may have a protective effect on acute lung injury (ALI) induced by limb ischemia/reperfusion (I/R) in rats. The PI3K/Akt, p38MAPK, and JAK2/STAT3 pathways are crucial in cell signaling transduction. The present study aims to verify the role of SO2 on limb I/R-induced ALI, and investigate whether PI3K/Akt, p38MAPK, and JAK2/STAT3 pathways were involved, as well as the relationship among the three pathways; we used specific inhibitors (LY294002, SB03580, and Stattic) to block them, respectively. The experimental methods of Western, ELISA, TUNEL, etc., were used to test the results. In the I/R group, the parameters of lung injury (MDA, MPO, TUNEL, cytokines) increased significantly, but the administration of Na2SO3/NaHSO3 attenuated the damage in the lung. The Western results showed that the rat's lung exist expression of P-STAT3, P-AKT, and P-p38 proteins. After I/R, P-STAT3, P-Akt, and P-p38 proteins expression all increased. After using Na2SO3/NaHSO3, P-Akt, and P-p38 proteins expression increased, but P-STAT3 protein expression decreased. We also found a strange phenomenon; compared to the I/R + SO2 group, the administration of stattic, P-p38 protein expression showed no change, but P-Akt protein expression increased (p < 0.05). In conclusion, SO2 has a protective effect on rats with limb I/R-induced ALI. The JAK2/STAT3, PI3K/Akt, and p38MAPK pathways are likely all involved in the process, and the JAK2/STAT3 pathway may have an impact on the P13K/Akt pathway.

Sevoflurane has been shown to improve ischemia/reperfusion injury (IRI) through several mechanisms, including amelioration of inflammatory response. However, there haven't been any studies considering the potential role of the complement system in sevoflurane-mediated amelioration of ischemia/reperfusion injury. Our purpose was to investigate the molecular mechanisms involved in sevoflurane preconditioning in liver and lung injury induced by liver ischemia-reperfusion (LIR), giving emphasis to the immunological mechanisms. In order to do that, fifty male Wistar rats were randomly allocated in five groups (n=10 each): Animals in group LIR received ketamine and xylazine and were then subjected to ischemia of the right and median hepatic lobe for 45 min and reperfusion for 6h. Group SEVO/LIR received sevoflurane and then LIR was induced, as in group LIR. Animals in group SHAM/LIR were anesthetized with ketamine and xylazine and then laparotomy followed. Group SHAM/SEVO received sevoflurane for 30 min and then laparotomy followed. Finally, in group VEN, animals only received ketamine and xylazine. Our results showed that sevoflurane preconditioning significantly improved liver-biochemical tests (decreased Alanine transaminase (ALT), Alkaline phosphatase (ALP), Aspartate transaminase (AST) and Alkaline phosphatase (ALP) levels) and limited inflammatory cell infiltration in BALF. Additionally, compared with the LIR group, the reduction in plasma C3 was significantly reduced in the SEVO/LIR group. No significant differences were observed in histological examination in the liver and lung. Immunostaining of the liver for Intracellular Adhesion Molecule 1 (ICAM1) however, showed a decrease in ICAM1 levels in the SEVO/LIR group. In the lung, sevoflurane seemed to exert no effect in ICAM1 levels. Caspase 3 (CASP3) levels in the liver and the lung also appeared unaffected by sevoflurane preconditioning. In the SEVO/LIR group, ICAM1 mRNA expression was significantly reduced in the liver. No statistical significantly differences were observed in Complement component 3 (C3), Complement component 5 (C5) and Clusterin (CLU) mRNA levels in the liver or the lung tissue. Summarizing, sevoflurane preconditioning seems to ameliorate LIR-induced injury in the rats, mediated by mechanisms that include ICAM1 and complement C3 down regulation., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Background: Creatine (Cr) is a dietary supplement that presents beneficial effects in experimental models of heart and brain ischemia and reperfusion (I/R) injury. It can improve adenosine 5'-triphosphate generation and reduce cell damage. This study evaluated the effects of Cr supplementation in a model of lung I/R., Methods: Forty male Wistar rats were divided into 4 groups: sham operated, Cr+sham, I/R, and Cr+I/R. We investigated the effects of 5 days of Cr supplementation (0.5 g/kg/day by gavage) before left pulmonary artery ischemia (90 minutes) and reperfusion (120 minutes) on pulmonary and systemic response., Results: Cr inhibited the I/R-induced increase in exhaled nitric oxide (p < 0.05), total cells (p < 0.01), and neutrophils (p < 0.001) in bronchoalveolar lavage fluid and in the systemic circulation (p < 0.001). The levels of interleukin-1β (p < 0.05), tissue damping, and tissue elastance (p < 0.05) were also minimized. Cr also inhibited pulmonary edema formation (total proteins in bronchoalveolar lavage fluid, p < 0.001; histologic edema index, p < 0.001) and neutrophils accumulation in lung tissue (p < 0.001). As possible mechanisms underlying Cr effects, we observed a reduced expression of caspase 3 (p < 0.05), reduced expression of Toll-like receptor (TLR) 4, and increased expression of TLR7 in lung tissue (p < 0.001)., Conclusions: Cr supplementation presents pulmonary and systemic protective effects in acute lung injury induced by I/R in rats. These beneficial effects seem to be related to the anti-inflammatory and anti-oxidant properties of Cr and modulation of TLRs., (Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Preventing acute kidney injury (AKI) in high-risk patients following medical interventions is a paramount challenge for clinical practice. Recent data from animal experiments and clinical trials indicate that remote ischemic preconditioning, represented by limb ischemic preconditioning, confers a protective action on the kidney. Ischemic preconditioning is effective in reducing the risk for AKI following cardiovascular interventions and the use of iodinated radiocontrast media. Nevertheless, the underlying mechanisms for this protective effect are elusive. A protective signal is conveyed from the remote site undergoing ischemic preconditioning, such as the limb, to target organs, such as the kidney, by multiple potential communication pathways, which may involve humoral, neuronal, and systemic mechanisms. Diverse transmitting pathways trigger a variety of signaling cascades, including the reperfusion injury salvage kinase and survivor activating factor enhancement pathways, all of which converge on glycogen synthase kinase 3β (GSK3β). Inhibition of GSK3β subsequent to ischemic preconditioning reinforces the Nrf2-mediated antioxidant defense, diminishes the nuclear factor-κB-dependent proinflammatory response, and exerts prosurvival effects ensuing from the desensitized mitochondria permeability transition. Thus, therapeutic targeting of GSK3β by ischemic preconditioning or by pharmacologic preconditioning with existing US Food and Drug Administration-approved drugs having GSK3β-inhibitory activities might represent a pragmatic and cost-effective adjuvant strategy for kidney protection and prophylaxis against AKI., (Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Surgical embolectomy for thrombosis and ischemia following femoral arterial cannulation in small infants is rare. The nonavailability of embolectomy balloons in small sizes and the small size of the native vessels pose a challenge in repair. We describe the use of a coronary angioplasty balloon for the purpose of embolectomy in a 2.5-kg infant with femoral arterial occlusion and limb ischemia., (© The Author(s) 2015.)

Background & Aims: Fatty acid binding protein 4 (FABP4) has been known as a mediator of inflammatory response in the macrophages and adipose tissue, but its hepatic function is poorly understood. The goal of this study is to investigate the role of FABP4 in liver ischemia/reperfusion (I/R), a clinical condition that involves both hypoxia and inflammation., Methods: To examine the I/R regulation of FABP4, mice were subjected to I/R surgery before being measured for FABP4 gene expression. Both loss-of-function (by using a pharmacological FABP4 inhibitor) and gain-of-function (by adenoviral overexpression of FABP4) were used to determine the functional relevance of FABP4 expression and its regulation during I/R. To determine the hypoxia responsive regulation of FABP4, primary mouse hepatocytes were exposed to hypoxia. The FABP4 gene promoter was cloned and its regulation by hypoxia inducible factor 1α (HIF-1α) was characterized by luciferase reporter gene, electrophoretic mobility shift, and chromatin immunoprecipitation assays., Results: We found that the hepatic expression of FABP4 was markedly induced by I/R. At the functional level, pharmacological inhibition of FABP4 alleviated the I/R injury, whereas adenoviral overexpression of FABP4 sensitized mice to I/R injury. We also showed that exposure of primary hepatocytes to hypoxia or transgenic overexpression of HIF-1α in the mouse liver was sufficient to induce the expression of FABP4. Our promoter analysis established FABP4 as a novel transcriptional target of HIF-1α., Conclusions: FABP4 is a hypoxia inducible gene that sensitizes mice to liver I/R injury. FABP4 may represent a novel therapeutic target, and FABP4 inhibitors may be used as therapeutic agents to manage hepatic I/R injury., (Copyright © 2015 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Introduction: Many pathways have been reported involving the effect of hydrogen-rich saline on protecting skin flap partial necrosis induced by the inflammation of ischemia/reperfusion injury. This study focused on the influence of hydrogen-rich saline treatment on apoptosis pathway of ASK-1/JNK and Bcl-2/Bax radio in I/R injury of skin flaps., Methods: Adult male Sprague-Dawley rats were divided into three groups. Group 1 was sham surgery group, Group 2 and 3 were ischemia/reperfusion surgery treated with physiological saline and hydrogen-rich saline respectively. Blood perfusion of flap was measured by Laser doppler flowmeters. Hematoxylin and eosin staining was used to observe morphological changes. Early apoptosis in skin flap was observed through TUNEL staining and presented as the percentage of TUNEL-positive cells of total cells. pASK-1, pJNK, Bcl-2 and Bax were examined by immunodetection. In addition Bcl-2, Bax and caspase-3 were detected by qPCR. Caspase-3 activity was also measured., Results: Compared to the Group 2, tissues from the group 3 were observed with a high expression of Bcl-2 and a low expression of pASK-1, pJNK, and Bax, a larger survival area and a high level of blood perfusion. Hydrogen-rich saline ameliorated inflammatory infiltration and decreased cell apoptosis., Conclusion: The results indicate that hydrogen-rich saline could ameliorate ischemia/reperfusion injury and improve flap survival rate by inhibiting the apoptosis factor and, at the same time, promoting the expression of anti-apoptosis factor., (Copyright © 2015. Published by Elsevier Ltd.)

Background: Epithelial cell (EC)-derived Interleukin-7 (IL-7) plays a crucial role in control of neighboring intestinal intraepithelial lymphocytes (IEL) development and homeostasis, and IEL derived keratinocyte growth factor (KGF) promotes intestinal epithelial growth, which was regulated by EC-derived IL-7. On this basis, we hypothesize that there is a crosstalk between IELs and ECs, and KGF could regulate the EC-derived IL-7 expression, which should be associated with the protective effects by KGF on intestinal injury., Methods: Histological evaluation was performed in small intestine tissues of patients with intestinal obstruction and IL-7 expression was detected by immunofluorescence. Intestinal epithelial cells (LoVo) and adult C57BL/6J mice undergoing ischemia/reperfusion injury were treated with recombinant KGF. KGF, KGF receptor(KGFR) and IL-7 expressions were measured with western blot and immunofluorescence analysis., Results: IL-7 expression increased in the mild ischemia while decreased in severe ischemia small intestinal tissues of patients with intestinal obstruction. KGF expression significantly decreased while IL-7 expression increased early after acute intestinal I/R administration in a mouse model. KGF treatment significantly increased the IL-7 expression both in vitro and in vivo, while when the KGFR was blocked, the findings above were absent. In addition, our results showed changes of IL-7 expression at different stages after acute intestinal I/R administration, KGF treatment significantly attenuated the decreasing of IL-7 expression caused by acute intestinal I/R., Conclusion: KGF could up-regulate the IL-7 expression both in vitro and in vivo through KGFR pathway, which should have associated with the protective effects of KGF in intestinal injury.

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]

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]

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.

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]

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]

OBJECTIVE: In this study, the effect of tocilizumab (TCZ) on lung tissue in lung ischemia-reperfusion (I/R) injury in rats was investigated. MATERIAL AND METHODS: A total of 24 Wistar rats were divided into 4 equal groups, with 6 rats in each group: Left lung I/R was applied to I/R groups. In the I/R groups, the left lung hilum was clamped for 45 minutes, and then the clamp was removed and reperfused for 120 minutes. In the TCZ groups, 4 mg/kg and 8 mg/kg of TCZ were administered intraperitoneally to the rats 30 minutes before surgery. RESULTS: The tumor necrosis factor-alpha mean value was not statistically significant between the groups (P = .091). Statistically significant results were observed between group I/R-TCZ (8 mg/kg) and group I/R for catalase. (P = .005). Statistically significant results were observed between group I/R-TCZ (8 mg/kg) and group I/R for malondialdehyde. (P = .009). The difference in total ischemia score between group I/R-TCZ (4 mg/kg) and group I/R-TCZ (8 mg/kg) and group I/R was statistically significant (P < .001). In terms of alveolar hemorrhage, there was a statistically significant difference between group I/R-TCZ (4 mg/kg) and group I/R-TCZ (8 mg/kg) and group I/R (P = .01 and P = .002, respectively). There was a statistically significant difference between group I/R-TCZ (8 mg/kg) and group I/R in terms of neutrophil accumulation (P = .01). In terms of interstitial edema, there was a statistically significant difference between group I/R-TCZ (4 mg/kg) and group I/R-TCZ (8 mg/kg) and group I/R (P = .006 and P = .001, respectively). In terms of pulmonary edema, there was a statistically significant difference between group I/R-TCZ (4 mg/kg) and group I/R-TCZ (8 mg/kg) and group I/R (P = .01 and P = .009, respectively). CONCLUSION: Lung tissue may be affected by I/R injury and this damage can be reversed with the use of TCZ. [ABSTRACT FROM AUTHOR]

Purpose: Hepatic ischemic post-conditioning (IPOC) is shown to protect the liver from injury induced by ischemia/reperfusion (IR). However, the mechanism underlying this protection has remained elusive. The present study aimed to investigate the role of the interleukin 6-Janus kinase-signal transducers and activators of transcription (IL-6-JAK-STAT) pathway in the protective effect of hepatic IPOC against the IR-induced injury in the liver. Methods: Twenty-five rats were randomly divided into 5 groups of (1) sham-operated, (2) IR, (3) IR+hepatic IPOC, (4) IR+tofacitinib (TOFA), and (5) IR+TOFA+hepatic IPOC. The changes induced by IR and the effects of different treatments were assessed by enzyme release, histopathological observations, the serum level of IL-6, and the occurrence of apoptosis detected via the expression of the Bax/Bcl-2 ratio. Results: The hepatic IPOC improved the liver injury induced by IR as shown by histological changes, reduction of IL-6 level, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) compared to the IR group (P <0.001,> P <0.05,> P P<0.05).> Conclusion: It suggests that the protective effect of hepatic IPOC against IR-induced injury may be mediated by activating the IL-6-JAK-STAT pathway. [ABSTRACT FROM AUTHOR]

While reperfusion, or restoration of coronary blood flow in acute myocardial infarction, is a requisite for myocardial salvage, it can paradoxically induce a specific damage known as ischemia/reperfusion (I/R) injury. Our understanding of the precise pathophysiological molecular alterations leading to I/R remains limited. In this study, we conducted a comprehensive and unbiased time-course analysis of post-translational modifications (PTMs) in the post-reperfused myocardium of two different animal models (pig and mouse) and evaluated the effect of two different cardioprotective therapies (ischemic preconditioning and neutrophil depletion). In pigs, a first wave of irreversible oxidative damage was observed at the earliest reperfusion time (20 min), impacting proteins essential for cardiac contraction. A second wave, characterized by irreversible oxidation on different residues and reversible Cys oxidation, occurred at late stages (6–12 h), affecting mitochondrial, sarcomere, and inflammation-related proteins. Ischemic preconditioning mitigated the I/R damage caused by the late oxidative wave. In the mouse model, the two-phase pattern of oxidative damage was replicated, and neutrophil depletion mitigated the late wave of I/R-related damage by preventing both Cys reversible oxidation and irreversible oxidation. Altogether, these data identify protein PTMs occurring late after reperfusion as an actionable therapeutic target to reduce the impact of I/R injury. [ABSTRACT FROM AUTHOR]

Background Sodium-calcium (Ca2+) exchanger isoform 1 (NCX1) is the dominant Ca2+ efflux mechanism in cardiomyocytes and is critical to maintaining Ca2+ homeostasis during excitation-contraction coupling. NCX1 activity has been implicated in the pathogenesis of cardiovascular diseases, but a lack of specific NCX1 blockers complicates experimental interpretation. Our aim was to develop a tamoxifen-inducible NCX1 knockout (KO) mouse to investigate compensatory adaptations of acute ablation of NCX1 on excitation-contraction coupling and intracellular Ca2+ regulation, and to examine whether acute KO of NCX1 confers resistance to triggered arrhythmia and ischemia/reperfusion injury. Methods and Results We used the α-myosin heavy chain promoter (Myh6)-MerCreMer promoter to create a tamoxifen-inducible cardiac-specific NCX1 KO mouse. Within 1 week of tamoxifen injection, NCX1 protein expression and current were dramatically reduced. Diastolic Ca2+ increased despite adaptive reductions in Ca2+ current and action potential duration and compensatory increases in excitation-contraction coupling gain, sarcoplasmic reticulum Ca2+ ATPase 2 and plasma membrane Ca2+ ATPase. As these adaptations progressed over 4 weeks, diastolic Ca2+ normalized and SR Ca2+ load increased. Left ventricular function remained normal, but mild fibrosis and hypertrophy developed. Transcriptomics revealed modification of cardiovascular-related gene networks including cell growth and fibrosis. NCX1 KO reduced spontaneous action potentials triggered by delayed afterdepolarizations and reduced scar size in response to ischemia/reperfusion. Conclusions Tamoxifen-inducible NCX1 KO mice adapt to acute genetic ablation of NCX1 by reducing Ca2+ influx, increasing alternative Ca2+ efflux pathways, and increasing excitation-contraction coupling gain to maintain contractility at the cost of mild Ca2+-activated hypertrophy and fibrosis and decreased survival. Nevertheless, KO myocytes are protected against spontaneous action potentials and ischemia/reperfusion injury.

Modulation of mitochondrial K channels represents a pharmacological strategy to promote cardioprotective effects. Isothiocyanates emerge as molecules capable of releasing hydrogen sulfide (H2S), an endogenous pleiotropic gasotransmitter responsible for anti-ischemic cardioprotective effects also through the involvement of mitoK channels. Erucin (ERU) is a natural isothiocyanate resulting from the enzymatic hydrolysis of glucosinolates (GSLs) present in Eruca sativa Mill. seeds, an edible plant of the Brassicaceae family. In this experimental work, the specific involvement of mitoKATP channels in the cardioprotective effect induced by ERU was evaluated in detail. An in vivo preclinical model of acute myocardial infarction was reproduced in rats to evaluate the cardioprotective effect of ERU. Diazoxide was used as a reference compound for the modulation of potassium fluxes and 5-hydroxydecanoic acid (5HD) as a selective blocker of KATP channels. Specific investigations on isolated cardiac mitochondria were carried out to evaluate the involvement of mitoKATP channels. The results obtained showed ERU cardioprotective effects against ischemia/reperfusion (I/R) damage through the involvement of mitoKATP channels and the consequent depolarizing effect, which in turn reduced calcium entry and preserved mitochondrial integrity. [ABSTRACT FROM AUTHOR]

Ischemia/reperfusion (IR) injury is an inevitable pathological event occurring when blood is resupplied to the tissues after a period of ischemia. One of major causes of IR injury is the overproduction of reactive oxygen species (ROS) including hydrogen peroxide (H 2 O 2), which mediates the expression of various inflammatory cytokines to exacerbate tissue damages. The overproduced H 2 O 2 could therefore serve as a diagnostic and therapeutic biomarker of IR injury. In this study, poly(boronated methacrylate) (pBMA) nanoparticles were developed as nanotheranostic agents for renal IR injury, which not only generate CO 2 bubbles to enhance the ultrasound contrast but also provide potent preventive effects in a H 2 O 2 -triggered manner. The surface of pBMA nanoparticles was decorated with taurodeoxycholic acid (TUDCA) that binds P-selectin overexpressed in inflamed tissues. In the mouse model of renal IR injury, TUDCA-coated pBMA (T-pBMA) nanoparticles preferentially accumulated in the injured kidney and markedly enhanced the ultrasound contrast. T-pBMA nanoparticles also effectively prevented renal IR injury by scavenging H 2 O 2 and suppressing the expression of inflammatory cytokines. Treatment progress of IR injury could be also monitored by echogenic T-pBMA nanoparticles. Given their targeting ability, excellent H 2 O 2 -responsiveness, anti-inflammatory activity and H 2 O 2 -triggered echogenicity, T-pBMA nanoparticles have excellent translational potential for the management of various H 2 O 2 -related diseases including IR injury. [Display omitted] [ABSTRACT FROM AUTHOR]

Previous studies have shown niacin has neuroprotective effects on the central nervous system. However, its specific effect on spinal cord ischemia/reperfusion injury has not yet been explored. This study aims to evaluate whether niacin can contribute neuroprotective effects on spinal cord ischemia/reperfusion injury. Rabbits were randomized into 4 groups of 8 animals: group I (control), group II (ischemia), group III (30 mg/kg methylprednisolone, intraperitoneal), and group IV (500 mg/kg niacin, intraperitoneal). The rabbits in group IV were premedicated with niacin for 7 days prior to inducing ischemia/reperfusion injury. The control group was subjected only to a laparotomy, while the remaining groups underwent spinal cord ischemia through a 20-minute occlusion of the aorta caudal to the left renal artery. Following the procedure, levels of catalase, malondialdehyde, xanthine oxidase, myeloperoxidase, and caspase-3 were analyzed. Ultrastructural, histopathological, and neurological evaluations were also performed. Spinal cord ischemia/reperfusion injury resulted in increased levels of xanthine oxidase, malondialdehyde, myeloperoxidase, and caspase-3, with a concomitant decrease in catalase levels. Treatment with methylprednisolone and niacin led to decreased levels of xanthine oxidase, malondialdehyde, myeloperoxidase, and caspase-3 and an increase in catalase. Both methylprednisolone and niacin treatments demonstrated improvements in histopathological, ultrastructural, and neurological assessments. Our findings suggest that niacin has antiapoptotic, anti-inflammatory, antioxidant, and neuroprotective effects at least equal to methylprednisolone in ischemia/reperfusion injury of the spinal cord. This study is the first to report the neuroprotective impact of niacin on spinal cord ischemia/reperfusion injury. Further research is warranted to elucidate the role of niacin in this context. [ABSTRACT FROM AUTHOR]

Aims No effective therapy is available in clinics to protect the heart from ischaemia/reperfusion (I/R) injury. Endothelial cells are activated after I/R, which may drive the inflammatory response by releasing ATP through pannexin1 (Panx1) channels. Here, we investigated the role of Panx1 in cardiac I/R. Methods and results Panx1 was found in cardiac endothelial cells, neutrophils, and cardiomyocytes. After in vivo I/R, serum Troponin-I, and infarct size were less pronounced in Panx1−/− mice, but leukocyte infiltration in the infarct area was similar between Panx1−/− and wild-type mice. Serum Troponin-I and infarct size were not different between mice with neutrophil-specific deletion of Panx1 and Panx1fl/fl mice, suggesting that cardioprotection by Panx1 deletion rather involved cardiomyocytes than the inflammatory response. Physiological cardiac function in wild-type and Panx1−/− hearts was similar. The time to onset of contracture and time to maximal contracture were delayed in Panx1−/− hearts, suggesting reduced sensitivity of these hearts to ischaemic injury. Moreover, Panx1−/− hearts showed better recovery of left ventricle developed pressure, cardiac contractility, and relaxation after I/R. Ischaemic preconditioning failed to confer further protection in Panx1−/− hearts. Panx1 was found in subsarcolemmal mitochondria (SSM). SSM in WT or Panx1−/− hearts showed no differences in morphology. The function of the mitochondrial permeability transition pore and production of reactive oxygen species in SSM was not affected, but mitochondrial respiration was reduced in Panx1−/− SSM. Finally, Panx1−/− cardiomyocytes had a decreased mitochondrial membrane potential and an increased mitochondrial ATP content. Conclusion Panx1−/− mice display decreased sensitivity to cardiac I/R injury, resulting in smaller infarcts and improved recovery of left ventricular function. This cardioprotective effect of Panx1 deletion seems to involve cardiac mitochondria rather than a reduced inflammatory response. Thus, Panx1 may represent a new target for controlling cardiac reperfusion damage. [ABSTRACT FROM AUTHOR]

Age‐related sensors Sirtuin1 (SIRT1) and Sirtuin3 (SIRT3) play an essential role in the protective response upon myocardial ischemia and/or reperfusion (I/R). However, the subcellular localization and co‐regulatory network between cardiac SIRT1 and SIRT3 remain unknown, especially their effects on age‐related metabolic regulation during acute ischemia and I/R. Here, we found that defects of cardiac SIRT1 or SIRT3 with aging result in an exacerbated cardiac physiological structural and functional deterioration after acute ischemic stress and failed recovery through reperfusion operation. In aged hearts, SIRT1 translocated into mitochondria and recruited more mitochondria SIRT3 to enhance their interaction during acute ischemia, acting as adaptive protection for the aging hearts from further mitochondria dysfunction. Subsequently, SIRT3‐targeted proteomics revealed that SIRT1 plays a crucial role in maintaining mitochondrial integrity through SIRT3‐mediated substrate metabolism during acute ischemic and I/R stress. Although the loss of SIRT1/SIRT3 led to a compromised PGC‐1α/PPARα‐mediated transcriptional control of fatty acid oxidation in response to acute ischemia and I/R, their crosstalk in mitochondria plays a more important role in the aging heart during acute ischemia. However, the increased mitochondria SIRT1‐SIRT3 interaction promoted adaptive protection to aging‐related fatty acid metabolic disorder via deacetylation of long‐chain acyl CoA dehydrogenase (LCAD) during ischemic insults. Therefore, the dynamic network of SIRT1/SIRT3 acts as a mediator that regulates adaptive metabolic response to improve the tolerance of aged hearts to ischemic insults, which will facilitate investigation into the role of SIRT1/SIRT3 in age‐related ischemic heart disease. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ischemia-reperfusion injury (IRI) can induce major changes in the function of different organs, including the liver. Studies have indicated that ischemic post-conditioning (HIPO) can protect the tissues against ischemia-reperfusion injury. OBJECTIVES: To investigate the antioxidant and anti-inflammatory effects of ischemia post-conditioning against the IRI of the rat liver through four 30-second cycles of alternating ischemia and reperfusion, before 24-hour persistent reperfusion. METHODS: Fifteen rats were randomly divided into 3 groups 1) operation control group, 2) ischemia-reperfusion (IR) group whose liver was exposed to 60-miute ischemia of by 24-hour reperfusion and 3) ischemic post-conditioning (IR+IPO) group underwent the same procedure as the second group except that before persistent reperfusion, the rats were subject to post-conditioning by four 30-second cycles of alternating ischemia and reperfusion. The changes induced by IRI and the antioxidant and anti-inflammatory effects of ischemic post-conditioning were assessed by the serum level of IL-6 using the ELISA method, malondialdehyde (MDA), and total antioxidant capacity (TAC). RESULTS: Ischemic post-conditioning potentiated antioxidant effects and reduced the inflammation caused by the IR in the liver. The serum level of IL-6 reduced from 394.4±126.4 to 124.4±29.07 pg/ml (post-conditioning group), and the tissue MDA reduced from 431.4±76.53 to 207.2±25.77 nmol/g) compared to the IR group. The data revealed that the levels of the indices returned almost to the level of the operation control group (P<0.001). Additionally, the total antioxidant capacity of the liver significantly improved (P<0.01) from 11.58±1.87 (in the IR group) to 17.53±2.51 mmol/mg (in the IR+IPO group). CONCLUSIONS: The study demonstrates that the protective effect of ischemic post-conditioning against IR-induced injury may be mediated through decreasing inflammation and improving antioxidant activities. [ABSTRACT FROM AUTHOR]

Introduction: The shortage of available donor hearts and the risk of ischemia/reperfusion injury restrict heart transplantation (HTX). Alpha-1-antitrypsin (AAT), a well-characterized inhibitor of neutrophil serine protease, is used in augmentation therapy to treat emphysema due to severe AAT deficiency. Evidence demonstrates its additional anti-inflammatory and tissue-protective effects. We hypothesized that adding human AAT in a preservation solution reduces graft dysfunction in a rat model of HTX following extended cold ischemic storage. Methods: The hearts from isogenic Lewis donor rats were explanted, stored for either 1h or 5h in cold Custodiol supplemented with either vehicle (1h ischemia, n=7 or 5h ischemia, n=7 groups) or 1 mg/ml AAT (1h ischemia+AAT, n=7 or 5h ischemia+AAT, n=9 groups) before heterotopic HTX. Left-ventricular (LV) graft function was evaluated in vivo 1.5h after HTX. Immunohistochemical detection of myeloperoxydase (MPO) was performed in myocardial tissue and expression of 88 gene quantified with PCR was analyzed both statistical and with machinelearning methods. Results: After HTX, LV systolic function (dP/dtmax 1h ischemia+AAT 4197 ± 256 vs 1h ischemia 3123 ± 110; 5h ischemia+AAT 2858 ± 154 vs 5h ischemia 1843 ± 104mmHg/s, p<0.05) and diastolic function (dP/dtmin 5h ischemia+AAT 1516 ± 68 vs 5h ischemia 1095 ± 67mmHg/s, p<0.05) at an intraventricular volume of 90µl were improved in the AAT groups compared with the corresponding vehicle groups. In addition, the rate pressure product (1h ischemia+AAT 53 ± 4 vs 1h ischemia 26 ± 1; 5h ischemia+AAT 37 ± 3 vs 5h ischemia 21 ± 1mmHg*beats/min at an intraventricular volume of 90µl; p<0.05) was increased in the AAT groups compared with the corresponding vehicle groups. Moreover, the 5h ischemia +AAT hearts exhibited a significant reduction in MPO-positive cell infiltration in comparison to the 5h ischemia group. Our computational analysis shows that ischemia+AAT network displays higher homogeneity, more positive and fewer negative gene correlations than the ischemia+placebo network. Discussion: We provided experimental evidence that AAT protects cardiac grafts from prolonged cold ischemia during HTX in rats. [ABSTRACT FROM AUTHOR]

Mildronate is a useful anti-ischemic agent and has antiinflammatory, antioxidant, and neuroprotective activities. The aim of this study is to investigate the potential neuroprotective effects of mildronate in the experimental rabbit spinal cord ischemia/reperfusion injury (SCIRI) model. Rabbits were randomized into 5 groups of 8 animals as groups 1 (control), 2 (ischemia), 3 (vehicle), 4 (30 mg/kg methylprednisolone [MP]), and 5 (100 mg/kg mildronate). The control group underwent only laparotomy. The other groups have the spinal cord ischemia model by a 20-minute aortic occlusion just caudal to the renal artery. The malondialdehyde and catalase levels and caspase-3, myeloperoxidase, and xanthine oxidase activities were investigated. Neurologic, histopathologic, and ultrastructural evaluations were also performed. The serum and tissue myeloperoxidase, malondialdehyde, and caspase-3 values of the ischemia and vehicle groups were statistically significantly higher than those of the MP and mildronate groups (P < 0.001). Serum and tissue catalase values of the ischemia and vehicle groups were statistically significantly lower than those of the control, MP, and mildronate groups (P < 0.001). The histopathologic evaluation showed a statistically significantly lower score in the mildronate and MP groups than in the ischemia and vehicle groups (P < 0.001). The modified Tarlov scores of the ischemia and vehicle groups were statistically significantly lower than those of the control, MP, and mildronate groups (P < 0.001). This study presented the antiinflammatory, antioxidant, antiapoptotic, and neuroprotective effects of mildronate on SCIRI. Future studies will elucidate its possible use in clinical settings in SCIRI. [ABSTRACT FROM AUTHOR]

Remote ischemic preconditioning (RIPC) represents one of the forms of innate cardioprotection. While being effective in animal models, its application in humans has not been always beneficial, which might be attributed to the presence of various comorbidities, such as hypertension, or being related to the confounding factors, such as patients' sex and age. RIPC has been shown to mediate its cardioprotective effects through the activation of Reperfusion Injury Salvage Kinase (RISK) pathway in healthy animals, however, scarce evidence supports this effect of RIPC in the hearts of spontaneously hypertensive (SHR) rats, in particular, in relationship with aging. The study aimed to investigate the effectiveness of RIPC in male SHR rats of different age and to evaluate the role of RISK pathway in the effect of RIPC on cardiac ischemic tolerance. RIPC was performed using three cycles of inflation/deflation of the pressure cuff placed on the hind limb of anesthetized rats aged three, five and eight months. Subsequently, hearts were excised, Langendorffperfused and exposed to 30-min global ischemia and 2-h reperfusion. Infarct-sparing and antiarrhythmic effects of RIPC were observed only in three and five months-old animals but not in eight months-old rats. Beneficial effects of RIPC were associated with increased activity of RISK and decreased apoptotic signaling only in three and five months-old animals. In conclusion, RIPC showed cardioprotective effects in SHR rats that were partially age-dependent and might be attributed to the differences in the activation of RISK pathway and various aspects of ischemia/reperfusion injury in aging animals. [ABSTRACT FROM AUTHOR]

Ischemia and perfusion (I/R) induce inflammation and oxidative stress, which play a notable role in tissue damage. The aim of this study was to investigate the role of an NADPH oxidase inhibitor (apocynin) in the protection of the heart from I/R injury. Hearts isolated from Wistar rats (n = 8 per group) were perfused with a modified Langendorff preparation. Left ventricular (LV) contractility and cardiovascular hemodynamics were evaluated by a data acquisition program, and infarct size was evaluated by 2,3,5-Triphenyl-2H-tetrazolium chloride (TTC) staining. Furthermore, the effect of apocynin on the pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and anti-inflammatory cytokine (IL-10) was evaluated using an enzyme linked immunosorbent assay (ELISA). Hearts were subjected to 30 min of regional ischemia, produced by ligation of the left anterior descending (LAD) coronary artery, followed by 30 min of reperfusion. Hearts were infused with apocynin before ischemia, during ischemia or at reperfusion. To understand the potential pathways of apocynin protection of the heart, a nitric oxide donor (S-nitroso-N-acetylpenicillamine, SNAP), nitric oxide blocker (N (gamma)-nitro-L-arginine methyl ester, L-Name), nicotinic acid adenine dinucleotide phosphate (NAADP) inhibiter (Ned-K), cyclic adenosine diphosphate ribose (cADPR) agonist, or CD38 blocker (Thiazoloquin (az)olin (on)e compound, 78c) was infused with apocynin. Antioxidants were evaluated by measuring superoxide dismutase (SOD) and catalase (CAT) activity. Apocynin infusion before ischemia or at reperfusion protected the heart by normalizing cardiac hemodynamics and decreasing the infarct size. Apocynin treatment resulted in a significant (p < 0.05) decrease in pro-inflammatory cytokine levels and a significant increase (p < 0.05) in anti-inflammatory and antioxidant levels. Apocynin infusion protected the heart by improving LV hemodynamics and coronary vascular dynamics. This treatment decreased the infarct size and inflammatory cytokine levels and increased anti-inflammatory cytokine and antioxidant levels. This protection follows a pathway involving CD38, nitric oxide and acidic stores. [ABSTRACT FROM AUTHOR]

Ischemia-reperfusion (IR) injury to the lower extremities causes damage to various tissues, notably the limbs. Because research in recent years have demonstrated that saffron and its components are useful in ischemic strokes, the goal of this study was to see whether Crocin (Cr), one of the active constituents in saffron, could protect the gastrocnemius muscle from IR injury. A total number of 32 Sprague-Dawley rats were randomized into four groups randomly: control, Cr, IR, and IR + Cr. Xylazine and ketamine were used to anesthetize all of the rats. The left lower limbs of the other two groups were subjected to 2 hr of ischemia and 2 hr of reperfusion with tourniquet, with the exception of the control and Cr groups. Tumor necrosis factor alfa (TNF-α), interleukin 6 (IL-6), IL-1β, total antioxidant status (TAS) and total oxidant status (TOS) levels were assessed in the blood as well as muscle IL-6, IL1β, SOD1-2, catalase (CAT) and glutathione peroxidase (GPx) expression. According to the IR group, increases in TAS levels and decreases in TNF-α, IL-6, and IL-1β levels were substantial in the Cr therapy group. Cr significantly reduced IL-6 and IL-1β mRNA expression levels in the muscle of the IR group and increased superoxide dismutases 1 (SOD1), SOD2, catalase (CAT), and GPx. Our data showed that Cr protected the gastrocnemius muscle from IR injury in rats and reduced inflammatory markers significantly. These effects of Cr might have been mediated by improved antioxidant enzyme activity, suppression of free radical generation and reduction of oxidative stress. [ABSTRACT FROM AUTHOR]

Objective: Testicular torsion is one of the most common genital diseases in males in adolescence and it should be treated as soon as possible without ipsilateral testicular dysfunction. We investigated the protective effect of Capsaicin, which is an active ingredient of red-hot pepper, an antioxidant substance, on tissue damage caused by ischemia/reperfusion (I/R). Materials and Methods: Forty male, 250-300 g adult male rats were divided into 4 groups, 10 in each group. The torsion was created by rotating the spermatic cord of both testicles counterclockwise by 720°. In the experimental group where we applied capsaicin, detorsion was performed after 2 h of torsion. Malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) were evaluated. Testicular tissue was stained with hematoxylin/eosin for histopathological evaluation. Results: In the Capsaicin group showed reduced tubular damage and seminiferous tubules in a structure similar to ischemia and spermatogenic cell series in the tubular wall and decreased edema in the interstitial area. SOD, MDA and CAT levels evaluated for the determination of lipid peroxidation were observed to be close to the control group values in the Capsaicin administered group. Conclusion: Capsaicin had a protective effect on I/R injury in the testicle. [ABSTRACT FROM AUTHOR]

Introduction: Cordycepin has been reported to exhibit hepatic protective and anti‐inflammatory properties. Here, we investigated the role of cordycepin in ischemia/reperfusion (IR)‐induced liver injury in a mouse model. Methods: Mice were pretreated with cordycepin by gavage for 3 weeks, followed by the establishment of the IR modeling. Liver injury, Suzuki's histological grading, hepatic apoptosis, and inflammatory responses were evaluated by biochemical and pathological analysis. Results: It was found that Cordycepin pretreatment at 50 mg/kg for 3 weeks attenuated IR‐induced liver injury, as reflected by the significant decrease of the levels of aspartate aminotransferase, alanine transaminase, lactate dehydrogenase, and low‐density lipoprotein. Cordycepin pretreatment also reduced histopathological changes, attenuated hepatocyte apoptosis, inflammatory responses in the livers of IR mice. Mechanically, toll‐like receptor 4/nuclear factor kappa‐B signaling in liver tissues was inhibited by Cordycepin pretreatment. Conclusions: In conclusion, Cordycepin pretreatment protects IR‐induced liver injury, which demonstrates its potential for the treatment of IR in the liver. [ABSTRACT FROM AUTHOR]

Endothelial dysfunction is a potential side effect of brain death (BD). Ischemia/reperfusion (IR) injury during heart transplantation may lead to further endothelial damage. Protective effects of alpha-1-antitrypsin (AAT), a human neutrophil serine protease inhibitor, have been demonstrated against IR injury. We hypothesized that AAT protects brain-dead rats' vascular grafts from IR injury. Donor rats were subjected to BD by inflation of a subdural balloon. After 5.5 h, aortic rings were immediately mounted in organ baths (BD, n = 6 rats) or preserved in saline, supplemented either with vehicle (BD-IR, n = 8 rats) or AAT (BD-IR + AAT, n = 14 rats) for 24 h. During organ bath experiment, rings from both IR groups were exposed to hypochlorite to simulate warm reperfusion-associated endothelial injury. Endothelial function was measured ex vivo. Immunohistochemical staining for caspases was carried out and DNA-strand breaks were evaluated using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling. Data are presented as median (interquartile range). AAT improved IR-induced decreased maximum endothelium-dependent vasorelaxation to acetylcholine in the BD-IR + AAT aortas compared to the BD-IR group (BD: 83 (9-28) % versus BD-IR: 49 (39-60) % versus BD-IR + AAT: 64 (24-42) %, P < 0.05). Additionally, an increase in the rings' sensitivity to acetylcholine was noted after AAT (pD 2 -value: BD-IR + AAT: 7.35 (7.06-7.89) versus BD-IR: 6.96 (6.65-7.21), P < 0.05). Caspase-3, -8, -9, and -12 immunoreactivity and the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells were significantly decreased by AAT. AAT alleviates endothelial dysfunction, prevents increased caspase-3, -8, -9, and -12 levels, and decreases apoptotic DNA breakage due to BD and IR injury. This suggests that AAT treatment may be therapeutically beneficial to reduce IR-induced vascular damage. [ABSTRACT FROM AUTHOR]

Spinal cord ischemia/reperfusion injury (SCII) is a severe complication driven by apoptosis and neuroinflammation. An increase in the expression of c‐Fos, a member of the AP‐1 family, is known as a neuronal activation marker in SCII. The AP‐1 family is composed of Jun, Fos, and is associated with the regulation of cytokines expression and apoptosis. Fra‐1 is a member of the Fos family, however, the contribution of Fra‐1 to SCII is still unclear. In our study, Fra‐1 was highly upregulated especially in neurons and microglia and promoted apoptosis by changing the expression of Bax/Bcl‐2 after SCII. Furthermore, we found that Fra‐1 directly regulated the transcription expression of S100A8. We demonstrated that knockdown of Fra‐1 alleviated S100A8 mediated neuronal apoptosis and inflammatory factor release, thus improved motor function after SCII. Interestingly, we showed that administration of TAK‐242, the TLR4 inhibitor, to the ischemia/reperfusion (I/R) injury induced rats suppressed the activation of the ERK and NF‐κB pathways, and further reduced Fra‐1 expression. In conclusion, we found that Fra‐1‐targeted S100A8 was expressed the upstream of Fra‐1, and the Fra‐1/S100A8 interaction formed a feedback loop in the signaling pathways activated by SCII. [ABSTRACT FROM AUTHOR]

Background. Ischemia/reperfusion (I/R) can cause damage to distant organs. Rutin is known to have antioxidant and anti-inflammatory properties, and inhibits cytokine and polymorphonuclear leukocyte (PMNL) infiltration. It may prevent the development of reperfusion injury. Objectives. This study aimed to examine the role of PMNLs in distant organ (lung) injury after a liver I/R procedure, and to evaluate the protective effects of rutin in rats using biochemical and immunohistochemical methods. Materials and methods. In this study, 18 Wistar albino male rats (255-275 g) were used. Experimental animals were divided into 3 groups: a liver I/R (LIR) group, a 50 mg/kg rutin+liver I/R (RLIR) group and a sham operation (SG) control group. Experimental results obtained from the RLIR group were compared with the LIR and SG groups. Results. Blood malondialdehyde (MDA) levels in the RLIR and SG groups were significantly lower compared to the LIR group (p < 0.001). Blood myeloperoxidase (MPO) activity in the RLIR and SG groups was significantly lower compared to the LIR group (p < 0.001). Total glutathione (tGSH) levels in the RLIR and SG groups were significantly higher compared to the LIR group (p < 0.001). Conclusions. Rutin can be used to prevent distant organ (lung) damage due to liver I/R. However, more extensive studies are needed on this issue. [ABSTRACT FROM AUTHOR]

The early-onset Parkinson's disease protein DJ-1 is a multifunctional protein that plays a protective role against ischemia and reperfusion (I/R) injury and oxidative stress. Despite lacking a canonical RNA-binding domain DJ-1 exhibits RNA-binding activity and multiple transcripts have been identified. However, no functional characterization has been provided to date. Here, we have investigated the DJ-1-interacting transcripts, as well as the role of DJ-1 RNA-binding activity during ischemia and reperfusion. Among the identified DJ-1-interacting transcripts, we have distinguished a significant enrichment of mRNAs encoding mitochondrial proteins. The effects of DJ-1 depletion on mitochondrial protein expression and mitochondrial morphology were investigated using a CRISPR/Cas9 generated DJ-1 knockout (DJ-1KO) cell model. DJ-1 depletion resulted in increased MTND2 protein expression in resting cells; however, after exposure to I/R, MTND2 levels were significantly reduced with respect to wild type cells. Increased mitochondrial fission was consistently found in DJ-1KO cells after I/R exposure. MTND2 transcript binding to DJ-1 was increased during ischemia. Our results indicate that the RNA-binding activity of DJ-1 shield mitochondrial transcripts from oxidative damage. [Display omitted] • DJ-1 preferentially interacts with mitochondria-encoded RNA transcripts. • DJ-1 RNA-binding increases during ischemia. • RNA-binding to DJ-1 protects transcripts from degradation during I/R. • Knockout of DJ-1 results in hyper-fused mitochondria in normoxia and increased fragmentation after I/R. [ABSTRACT FROM AUTHOR]

Dexpanthenol (DXP) reportedly protects tissues against oxidative damage in various inflammation models. This study aimed to evaluate its effects on oxidative stress, inflammation, apoptosis, and neurological recovery in an experimental rabbit spinal cord ischemia/reperfusion injury (SCIRI) model. Rabbits were randomized into 5 groups of 8 animals each: group 1 (control), group 2 (ischemia), group 3 (vehicle), group 4 (methylprednisolone, 30 mg/kg), and group 5 (DXP, 500 mg/kg). The control group underwent laparotomy only, whereas other groups were subjected to spinal cord ischemia by aortic occlusion (just caudal to the 2 renal arteries) for 20 min. After 24 h, a modified Tarlov scale was employed to record neurological examination results. Malondialdehyde and caspase-3 levels and catalase and myeloperoxidase activities were analyzed in tissue and serum samples. Xanthine oxidase activity was measured in the serum. Histopathological and ultrastructural evaluations were also performed in the spinal cord. After SCIRI, serum and tissue malondialdehyde and caspase-3 levels and myeloperoxidase and serum xanthine oxidase activities were increased (P < 0.05–0.001). However, serum and tissue catalase activity decreased significantly (P < 0.001). DXP treatment was associated with lower malondialdehyde and caspase-3 levels and reduced myeloperoxidase and xanthine oxidase activities but increased catalase activity (P < 0.05–0.001). Furthermore, DXP was associated with better histopathological, ultrastructural, and neurological outcome scores. This study was the first to evaluate antioxidant, anti-inflammatory, antiapoptotic, and neuroprotective effects of DXP on SCIRI. Further experimental and clinical investigations are warranted to confirm that DXP can be administered to treat SCIRI. [ABSTRACT FROM AUTHOR]

Ischemia/reperfusion (IR) injury contributes to disability and mortality worldwide. Due to the complicated mechanisms and lack of proper therapeutic targets, few interventions are available that specifically target the pathogenesis of IR injury. Regulated cell death (RCD) of endothelial and parenchymal cells is recognized as the promising intervening target. Recent advances in IR injury suggest that small molecules exhibit beneficial effects on various RCD against IR injury, including apoptosis, necroptosis, autophagy, ferroptosis, pyroptosis, and parthanatos. Here, we describe the mechanisms behind these novel promising therapeutic targets and explain the machinery powering the small molecules. These small molecules exert protection by targeting endothelial or parenchymal cells to alleviate IR injury. Therapies of the ideal combination of small molecules targeting multiple cell types have shown potent synergetic therapeutic effects, laying the foundation for novel strategies to attenuate IR injury. [ABSTRACT FROM AUTHOR]