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Defibrillation remains the optimal therapy for terminating ventricular fibrillation (VF) in out‐of‐hospital cardiac arrest (OHCA) patients, with reported shock success rates of ∼90%. A key persistent challenge, however, is the high rate of VF recurrence (∼50–80%) seen during post‐shock cardiopulmonary resuscitation (CPR). Studies have shown that the incidence and time spent in recurrent VF are negatively associated with neurologically‐intact survival. Recurrent VF also results in the administration of extra shocks at escalating energy levels, which can cause cardiac dysfunction. Unfortunately, the mechanisms underlying recurrent VF remain poorly understood. In particular, the role of chest‐compressions (CC) administered during CPR in mediating recurrent VF remains controversial. In this review, we first summarize the available clinical evidence for refibrillation occurring during CPR in OHCA patients, including the postulated contribution of CC and non‐CC related pathways. Next, we examine experimental studies highlighting how CC can re‐induce VF via direct mechano‐electric feedback. We postulate the ionic mechanisms involved by comparison with similar phenomena seen in commotio cordis. Subsequently, the hypothesized contribution of partial cardiac reperfusion (either as a result of CC or CC independent organized rhythm) in re‐initiating VF in a globally ischaemic heart is examined. An overview of the proposed ionic mechanisms contributing to VF recurrence in OHCA during CPR from a cellular level to the whole heart is outlined. Possible therapeutic implications of the proposed mechanistic theories for VF recurrence in OHCA are briefly discussed. [ABSTRACT FROM AUTHOR]

Key points Renal ischaemia and reperfusion (I/R) is caused by a sudden temporary impairment of the blood flow. I/R is a prevalent cause of acute kidney injury. As nitric oxide generated by inducible nitric oxide synthase (iNOS) has detrimental effects during I/R, the pharmacological blockade of iNOS has been proposed as a potential strategy to prevent I/R injury. The aim of this study was to improve the understanding of 1400W (an iNOS inhibitor) on renal I/R as a pharmacological strategy against kidney disease. BALB/c mice received 30 min of bilateral ischaemia, followed by 48 h or 28 days of reperfusion. Vehicle or 1400W (10 mg/kg) was administered 30 min before inducing ischaemia. We found that after 48 h of reperfusion 1400W decreased the serum creatinine, blood urea nitrogen, neutrophil gelatinase‐associated lipocalin and proliferating cell nuclear antigen 3 in the I/R animals. Unexpectedly, we observed mRNA upregulation of genes involved in kidney injury, cell‐cycle arrest, inflammation, mesenchymal transition and endothelial activation in the renal medulla of sham animals treated with 1400W. We also explored if 1400W promoted chronic kidney dysfunction 28 days after I/R and did not find significant alterations in renal function, fibrosis, blood pressure or mortality. The results provide evidence that 1400W may have adverse effects in the renal medulla. Importantly, our data point to 1400W‐induced endothelial dysfunction, establishing therapeutic limitations for its use. Acute kidney injury is a global health problem associated with high morbidity and mortality. The pharmacological blockade of inducible nitric oxide synthase (iNOS) has been proposed as a potential strategy to prevent AKI induced by ischaemia and reperfusion (I/R). Our main finding is that 1400W, a selective and irreversible iNOS inhibitor with low toxicity that is proposed as a therapeutic strategy to prevent kidney I/R injury, produces aberrant gene expression in the medulla associated to tissue injury, cell cycle arrest, inflammation, mesenchymal transition and endothelial activation. The negative effect of 1400W observed in the renal medulla at 48 h from drug administration, is transient as it did not translate into a chronic kidney disease condition. [ABSTRACT FROM AUTHOR]

Abstract Hindlimb ischaemia–reperfusion (IR) is among the most prominent pathophysiological conditions observed in peripheral artery disease (PAD). An exaggerated arterial blood pressure (BP) response during exercise is associated with an elevated risk of cardiovascular events in individuals with PAD. However, the precise mechanisms leading to this exaggerated BP response are poorly elucidated. The P2X3 signalling pathway, which plays a key role in modifying the exercise pressor reflex (EPR), is the focus of the present study. We determined the regulatory role of P2X3 on the EPR in a rat model of hindlimb IR. In vivo and in vitro approaches were used to determine the expression and functions of P2X3 in muscle afferent nerves and EPR in IR rats. We found that in IR rats there was (1) upregulation of P2X3 protein expression in the L4–6 dorsal root ganglia (DRG); (2) amplified P2X currents in isolated isolectin B4 (IB4)‐positive muscle DRG neurons; and (3) amplification of the P2X‐mediated BP response. We further verified that both A‐317491 and siRNA knockdown of P2X3 significantly decreased the activity of P2X currents in isolated muscle DRG neurons. Moreover, inhibition of muscle afferents’ P2X3 receptor using A‐317491 was observed to alleviate the exaggerated BP response induced by static muscle contraction and P2X‐induced BP response by α,β‐methylene ATP injection. P2X3 signalling pathway activity is amplified in muscle afferent DRG neurons in regulating the EPR following hindlimb IR.

Hindlimb ischaemia–reperfusion (IR) is among the most prominent pathophysiological conditions observed in peripheral artery disease (PAD). An exaggerated arterial blood pressure (BP) response during exercise is associated with an elevated risk of cardiovascular events in individuals with PAD. However, the precise mechanisms leading to this exaggerated BP response are poorly elucidated. The P2X3 signalling pathway, which plays a key role in modifying the exercise pressor reflex (EPR), is the focus of the present study. We determined the regulatory role of P2X3 on the EPR in a rat model of hindlimb IR. In vivo and in vitro approaches were used to determine the expression and functions of P2X3 in muscle afferent nerves and EPR in IR rats. We found that in IR rats there was (1) upregulation of P2X3 protein expression in the L4–6 dorsal root ganglia (DRG); (2) amplified P2X currents in isolated isolectin B4 (IB4)‐positive muscle DRG neurons; and (3) amplification of the P2X‐mediated BP response. We further verified that both A‐317491 and siRNA knockdown of P2X3 significantly decreased the activity of P2X currents in isolated muscle DRG neurons. Moreover, inhibition of muscle afferents' P2X3 receptor using A‐317491 was observed to alleviate the exaggerated BP response induced by static muscle contraction and P2X‐induced BP response by α,β‐methylene ATP injection. P2X3 signalling pathway activity is amplified in muscle afferent DRG neurons in regulating the EPR following hindlimb IR. What is the central question of this study?Is the P2X3 signal pathway engaged in the exaggerated exercise pressor reflex (EPR) response in the ischaemia–reperfusion (IR) injury of peripheral artery disease (PAD)?What is the main finding and its importance?IR upregulates expression of the P2X3 receptor and increases the P2X currents in muscle afferent DRG neurons. Pharmacological inhibition using A‐317491 (P2X3 antagonist) and the genetic knockdown of P2X3 reduce the P2X currents in the muscle afferent DRG neurons. A‐317491 also attenuates the exacerbated EPR response following IR.The findings provide evidence that interventions attenuating the P2X3 signalling pathway may enhance tolerance of and adherence to exercise rehabilitation for PAD patients. [ABSTRACT FROM AUTHOR]

Abstract Flap necrosis, the most prevalent postoperative complication of reconstructive surgery, is significantly associated with ischaemia–reperfusion injury. Recent research indicates that exosomes derived from bone marrow mesenchymal stem cells (BMSCs) hold potential therapeutic applications in several diseases. Traditionally, BMSCs are cultured under normoxic conditions, a setting that diverges from their physiological hypoxic environment in vivo. Consequently, we propose a method involving the hypoxic preconditioning of BMSCs, aimed at exploring the function and the specific mechanisms of their exosomes in ischaemia–reperfusion skin flaps. This study constructed a 3 × 6 cm2 caudal superficial epigastric skin flap model and subjected it to ischaemic conditions for 6 h. Our findings reveal that exosomes from hypoxia-pretreated BMSCs significantly promoted flap survival, decrease MCP-1, IL-1β, and IL-6 levels in ischaemia–reperfusion injured flap, and reduce oxidative stress injury and apoptosis. Moreover, results indicated that Hypo-Exo provides protection to vascular endothelial cells from ischaemia–reperfusion injury both in vivo and in vitro. Through high-throughput sequencing and bioinformatics analysis, we further compared the differential miRNA expression profiles between Hypo-Exo and normoxic exosomes. Results display the enrichment of several pathways, including autophagy and mTOR. We have also elucidated a mechanism wherein Hypo-Exo promotes the survival of ischaemia–reperfusion injured flaps. This mechanism involves carrying large amounts of miR-421-3p, which target and regulate mTOR, thereby upregulating the expression of phosphorylated ULK1 and FUNDC1, and subsequently further activating autophagy. In summary, hypoxic preconditioning constitutes an effective and promising method for optimizing the therapeutic effects of BMSC-derived exosomes in the treatment of flap ischaemia–reperfusion injury.

Abstract Aims Ischaemia–reperfusion injury (IRI) following myocardial infarction remains a challenging topic in acute cardiac care and consecutively arising heart failure represents a severe long‐term consequence. The extent of neutrophil infiltration and neutrophil‐mediated cellular damage are thought to be aggravating factors enhancing primary tissue injury. Toll‐like receptor 9 was found to be involved in neutrophil activation as well as chemotaxis and may represent a target in modulating IRI, aspects we aimed to illuminate by pharmacological inhibition of the receptor. Methods and results Forty‐nine male adult Sprague–Dawley rats were used. IRI was induced by occlusion of the left coronary artery and subsequent snare removal after 30 min. Oligonucleotide (ODN) 2088, a toll‐like receptor 9 (TLR9) antagonist, control‐ODN, or DNase, were administered at the time of reperfusion and over 24 h via a mini‐osmotic pump. The hearts were harvested 24 h or 4 weeks after left coronary artery occlusion and immunohistochemical staining was performed. Echocardiography was done after 1 and 4 weeks to determine ventricular function. Inhibition of TLR9 by ODN 2088 led to left ventricular wall thinning (P = 0.003) in association with drastically enhanced neutrophil infiltration (P = 0.005) and increased markers of tissue damage. Additionally, an up‐regulation of the chemotactic receptor CXCR2 (P = 0.046) was found after TLR9 inhibition. No such effects were observed in control‐ODN or DNase‐treated animals. We did not observe changes in monocyte content or subset distribution, hinting towards neutrophils as the primary mediators of the exerted tissue injury. Conclusions Our data indicate a TLR9‐dependent, negative regulation of neutrophil infiltration. Blockage of TLR9 appears to prevent the down‐regulation of CXCR2, followed by an uncontrolled migration of neutrophils towards the area of infarction and the exertion of disproportional tissue injury resulting in potential aneurysm formation. In comparison with previous studies conducted in TLR−/− mice, we deliberately chose a transient pharmacological inhibition of TLR9 to highlight effects occurring in the first 24 h following IRI.

Aims Empagliflozin (EMPA), a potent inhibitor of the renal sodium–glucose cotransporter 2 and an effective treatment for Type 2 diabetes, has been shown to have cardioprotective effects, independent of improved glycaemic control. Several non-canonical mechanisms have been proposed to explain these cardiac effects, including increasing circulating ketone supply to the heart. This study aims to test whether EMPA directly alters cardiac ketone metabolism independent of supply. Methods and results The direct effects of EMPA on cardiac function and metabolomics were investigated in Langendorff rat heart perfused with buffer containing 5 mM glucose, 4 mM β-hydroxybutyrate (βHb) and 0.4 mM intralipid, subject to low flow ischaemia/reperfusion. Cardiac energetics were monitored in situ using 31P NMR spectroscopy. Steady-state 13C labelling was performed by switching 12C substrates for 13C1 glucose or 13C4 βHb and 13C incorporation into metabolites determined using 2D 1H-13C HSQC NMR spectroscopy. EMPA treatment improved left ventricular-developed pressure during ischaemia and reperfusion compared to vehicle-treated hearts. In EMPA-treated hearts, total adenosine triphosphate (ATP) and phosphocreatine (PCr) levels, and Gibbs free energy for ATP hydrolysis were significantly higher during ischaemia and reperfusion. EMPA treatment did not alter the incorporation of 13C from glucose into glycolytic products lactate or alanine neither during ischaemia nor reperfusion. In ischaemia, EMPA led to a decrease in 13C1 glucose incorporation and a concurrent increase in 13C4 βHb incorporation into tricarboxylic acid (TCA) cycle intermediates succinate, citrate, and glutamate. During reperfusion, the concentration of metabolites originating from 13C1 glucose was similar to vehicle but those originating from 13C4 βHb remained elevated in EMPA-treated hearts. Conclusion Our findings indicate that EMPA causes a switch in metabolism away from glucose oxidation towards increased ketone utilization in the rat heart, thereby improving function and energetics both during ischaemia and recovery during reperfusion. This preference of ketone utilization over glucose was observed under conditions of constant supply of substrate, suggesting that EMPA acts directly by modulating cardiac substrate preference, independent of substrate availability. The mechanisms underlying our findings are currently unknown, warranting further study. [ABSTRACT FROM AUTHOR]

Abstract Background Adipose‐derived mesenchymal stem cells (ADMSCs) and their extracellular vesicles (EVs) are a promising source of therapies for ischaemia‐reperfusion (IR) because of their potent anti‐inflammatory and immunomodulatory properties. Objectives The aims of this study were to explore the therapeutic efficacy and potential mechanism of ADMSC‐EVs in canine renal IR injury. Methods Mesenchymal stem cells (MSCs) and EVs were isolated and characterised for surface markers. A canine IR model administered with ADMSC‐EVs was used to evaluate therapeutic effects on inflammation, oxidative stress, mitochondrial damage and apoptosis. Results CD105, CD90 and beta integrin ITGB were positively expressed in MSCs, while CD63, CD9 and intramembrane marker TSG101 were positively expressed in EVs. Compared with the IR model group, there was less mitochondrial damage and reduction in quantity of mitochondria in the EV treatment group. Renal IR injury led to severe histopathological lesions and significant increases in biomarkers of renal function, inflammation and apoptosis, which were attenuated by the administration of ADMSC‐EVs. Conclusions Secretion of EVs by ADMSCs exhibited therapeutic potential in renal IR injury and may lead to a cell‐free therapy for canine renal IR injury. These findings revealed that canine ADMSC‐EVs potently attenuate renal IR injury‐induced renal dysfunction, inflammation and apoptosis, possibly by reducing mitochondrial damage.

Flap necrosis, the most prevalent postoperative complication of reconstructive surgery, is significantly associated with ischaemia–reperfusion injury. Recent research indicates that exosomes derived from bone marrow mesenchymal stem cells (BMSCs) hold potential therapeutic applications in several diseases. Traditionally, BMSCs are cultured under normoxic conditions, a setting that diverges from their physiological hypoxic environment in vivo. Consequently, we propose a method involving the hypoxic preconditioning of BMSCs, aimed at exploring the function and the specific mechanisms of their exosomes in ischaemia–reperfusion skin flaps. This study constructed a 3 × 6 cm2 caudal superficial epigastric skin flap model and subjected it to ischaemic conditions for 6 h. Our findings reveal that exosomes from hypoxia-pretreated BMSCs significantly promoted flap survival, decrease MCP-1, IL-1β, and IL-6 levels in ischaemia–reperfusion injured flap, and reduce oxidative stress injury and apoptosis. Moreover, results indicated that Hypo-Exo provides protection to vascular endothelial cells from ischaemia–reperfusion injury both in vivo and in vitro. Through high-throughput sequencing and bioinformatics analysis, we further compared the differential miRNA expression profiles between Hypo-Exo and normoxic exosomes. Results display the enrichment of several pathways, including autophagy and mTOR. We have also elucidated a mechanism wherein Hypo-Exo promotes the survival of ischaemia–reperfusion injured flaps. This mechanism involves carrying large amounts of miR-421-3p, which target and regulate mTOR, thereby upregulating the expression of phosphorylated ULK1 and FUNDC1, and subsequently further activating autophagy. In summary, hypoxic preconditioning constitutes an effective and promising method for optimizing the therapeutic effects of BMSC-derived exosomes in the treatment of flap ischaemia–reperfusion injury. [ABSTRACT FROM AUTHOR]

Aims: Ischaemia–reperfusion injury (IRI) following myocardial infarction remains a challenging topic in acute cardiac care and consecutively arising heart failure represents a severe long‐term consequence. The extent of neutrophil infiltration and neutrophil‐mediated cellular damage are thought to be aggravating factors enhancing primary tissue injury. Toll‐like receptor 9 was found to be involved in neutrophil activation as well as chemotaxis and may represent a target in modulating IRI, aspects we aimed to illuminate by pharmacological inhibition of the receptor. Methods and results: Forty‐nine male adult Sprague–Dawley rats were used. IRI was induced by occlusion of the left coronary artery and subsequent snare removal after 30 min. Oligonucleotide (ODN) 2088, a toll‐like receptor 9 (TLR9) antagonist, control‐ODN, or DNase, were administered at the time of reperfusion and over 24 h via a mini‐osmotic pump. The hearts were harvested 24 h or 4 weeks after left coronary artery occlusion and immunohistochemical staining was performed. Echocardiography was done after 1 and 4 weeks to determine ventricular function. Inhibition of TLR9 by ODN 2088 led to left ventricular wall thinning (P = 0.003) in association with drastically enhanced neutrophil infiltration (P = 0.005) and increased markers of tissue damage. Additionally, an up‐regulation of the chemotactic receptor CXCR2 (P = 0.046) was found after TLR9 inhibition. No such effects were observed in control‐ODN or DNase‐treated animals. We did not observe changes in monocyte content or subset distribution, hinting towards neutrophils as the primary mediators of the exerted tissue injury. Conclusions: Our data indicate a TLR9‐dependent, negative regulation of neutrophil infiltration. Blockage of TLR9 appears to prevent the down‐regulation of CXCR2, followed by an uncontrolled migration of neutrophils towards the area of infarction and the exertion of disproportional tissue injury resulting in potential aneurysm formation. In comparison with previous studies conducted in TLR−/− mice, we deliberately chose a transient pharmacological inhibition of TLR9 to highlight effects occurring in the first 24 h following IRI. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate the protective effects of gallic acid (GA) in the rat intestine against ischaemia-reperfusion (IR) injury. Materials and methods: Thirty male Wistar albino rats with a mean weight of 200–250 g were used. Animals were categorized into the sham, IR, and IR+GA groups. Ischaemia of the intestine was induced for 3 h by occluding the superior mesenteric artery (SMA) and then left for 3 h of reperfusion. In the IR+GA group, after ischaemia induction, 50 mg/kg GA was orally administered to the animals. Blood samples were collected for biochemical assays. Intestinal tissues were excised for histopathologic and immunohistochemical processing. Results: Malondialdehyde (MDA) levels were increased, and catalase (CAT) and glutathione (GSH) levels were decreased in the IR group compared to the sham group. After GA treatment, MDA levels decreased and CAT and GSH levels increased in the GA-treated group compared to the IR group. In the sham group, normal intestinal histology was observed. In the IR group, the villi structures were completely degenerated. In the IR+GA group, histology was improved after GA treatment. In the sham group, the caspase-3 reaction was generally negative in the epithelium and glands. In the IR group, the caspase-3 reaction increased in apoptotic bodies and inflammatory cells. The caspase-3 reaction was negative in goblet cells and the epithelium. A moderate caspase-3 reaction was observed in the IR+GA group. The beclin-1 reaction was negative in epithelial cells and goblet cells in villi in the sham group. In the IR group, the beclin-1 reaction was positive in the degenerated villi. An intense beclin-1 reaction was also observed in some inflammatory cells. After GA treatment, the beclin-1 reaction was positive in a few cells. In general, moderate beclin-1 positivity was observed. Conclusions: Gallic acid, with its antioxidative effect, inhibited the apoptotic pathway (caspase-3) through beclin-1 regulation. [ABSTRACT FROM AUTHOR]

Zynamite PX®, a mango leaf extract combined with quercetin, enhances exercise performance by unknown molecular mechanisms. Twenty-five volunteers were assigned to a control (17 males) or supplementation group (8 males, receiving 140 mg of Zynamite® + 140 mg quercetin/8 h for 2 days). Then, they performed incremental exercise to exhaustion (IE) followed by occlusion of the circulation in one leg for 60 s. Afterwards, the cuff was released, and a 30 s sprint was performed, followed by 90 s circulatory occlusion (same leg). Vastus lateralis muscle biopsies were obtained at baseline, 20 s after IE (occluded leg) and 10 s after Wingate (occluded leg), and bilaterally at 90 s and 30 min post exercise. Compared to the controls, the Zynamite PX® group showed increased basal protein expression of Thr287-CaMKIIδD (2-fold, p = 0.007) and Ser9-GSK3β (1.3-fold, p = 0.005) and a non-significant increase of total NRF2 (1.7-fold, p = 0.099) and Ser40-NRF2 (1.2-fold, p = 0.061). In the controls, there was upregulation with exercise and recovery of total NRF2, catalase, glutathione reductase, and Thr287-CaMKIIδD (1.2–2.9-fold, all p < 0.05), which was not observed in the Zynamite PX® group. In conclusion, Zynamite PX® elicits muscle signaling changes in resting skeletal muscle resembling those described for exercise training and partly abrogates the stress kinases responses to exercise as observed in trained muscles. [ABSTRACT FROM AUTHOR]

Heart failure continues to be a common and deadly sequela of myocardial infarction (MI). Despite strong evidence suggesting the importance of myocardial mechanics in cardiac remodelling, many MI studies still rely on two-dimensional analyses to estimate global left ventricular (LV) function. Here, we integrated four-dimensional ultrasound with three-dimensional strain mapping to longitudinally characterize LV mechanics within and around infarcts in order to study the post-MI remodelling process. To induce infarcts with varying severities, we separated 15 mice into three equal-sized groups: (i) sham, (ii) 30 min ischaemia-reperfusion, and (iii) permanent ligation of the left coronary artery. Four-dimensional ultrasound from a high-frequency small animal system was used to monitor changes in LV geometry, function and strain over 28 days. We reconstructed three-dimensional myocardial strain maps and showed that strain profiles at the infarct border followed a sigmoidal behaviour. We also identified that mice with mild remodelling had significantly higher strains in the infarcted myocardium than those with severe injury. Finally, we developed a new approach to non-invasively estimate infarct size from strain maps, which correlated well with histological results. Taken together, the presented work provides a thorough approach to quantify regional strain, an important component when assessing post-MI remodelling.

Heart failure continues to be a common and deadly sequela of myocardial infarction (MI). Despite strong evidence suggesting the importance of myocardial mechanics in cardiac remodelling, many MI studies still rely on two-dimensional analyses to estimate global left ventricular (LV) function. Here, we integrated four-dimensional ultrasound with three-dimensional strain mapping to longitudinally characterize LV mechanics within and around infarcts in order to study the post-MI remodelling process. To induce infarcts with varying severities, we separated 15 mice into three equal-sized groups: (i) sham, (ii) 30 min ischaemia-reperfusion, and (iii) permanent ligation of the left coronary artery. Four-dimensional ultrasound from a high-frequency small animal system was used to monitor changes in LV geometry, function and strain over 28 days. We reconstructed three-dimensional myocardial strain maps and showed that strain profiles at the infarct border followed a sigmoidal behaviour. We also identified that mice with mild remodelling had significantly higher strains in the infarcted myocardium than those with severe injury. Finally, we developed a new approach to non-invasively estimate infarct size from strain maps, which correlated well with histological results. Taken together, the presented work provides a thorough approach to quantify regional strain, an important component when assessing post-MI remodelling.

p21-Activated kinase 4 (PAK4), one of the serine/threonine kinases activated by Rho-family GTPases, has been widely studied as an oncogenic protein that is overexpressed in many types of cancers. In our recent study, PAK4 upregulation was observed in mice exhibiting hepatic ischaemia-reperfusion (I/R) and in liver transplantation patients. Liver I/R injury was also attenuated in Pak4 KO mice. Herein, we report a novel series of pyrazolo[3,4-d]pyrimidine derivatives of type I ½ PAK4 inhibitors. The most potent compound SPA7012 was evaluated to determine the pharmacological potential of PAK4 inhibitor in I/R injury in mice. Mice with I/R injury showed typical patterns of liver damage, as demonstrated by increases in serum levels of aminotransferases and proinflammatory cytokines, hepatocellular necrosis and apoptosis, and inflammatory cell infiltration, relative to sham mice. Conversely, intraperitoneal administration of SPA7012 dramatically attenuated biochemical and histopathologic changes. Mechanistically, stabilisation of nuclear factor-erythroid 2-related factor 2 (Nrf2), a master regulator of anti-oxidative response, was observed following SPA7012 treatment. SPA7012 treatment in primary hepatocytes also attenuated hypoxia-reoxygenation-induced apoptotic cell death and inflammation. Together, these results provide experimental evidence supporting the use of PAK4 inhibitors for alleviation of I/R-induced liver damage.

Context Globally, the morbidity and mortality of cardiovascular diseases remain high. Didymin, a flavonoid glycoside, has long been used as a dietary antioxidant.Objective To determine the role of didymin in myocardial infarction (MI), and its possible myocardial protective mechanism.Materials and methods C57/BL6 mice (aged 6–8 weeks, n = 40) were divided into five groups: sham group, ischaemia–reperfusion (I/R) group, I/R + didymin (1 mg/kg) group, I/R + didymin (2 mg/kg) group and I/R + didymin (4 mg/kg) group. Didymin was administered intragastrically daily before I/R for 5 consecutive days. H9C2 cells were divided into five groups: control group, H/R group, H/R + didymin (3 μM) group, H/R + didymin (10 μM) group and H/R + didymin (30 μM) group. H9C2 cells were treated with didymin for 24 h before hypoxia/reoxygenation (H/R).Results In vivo, didymin reduced the pathological damage and fibrosis of myocardial tissues, decreased the levels of lactate dehydrogenase, creatine kinase, connective tissue growth factor, collagen I and collagen III. Moreover, didymin reduced myocardial apoptosis, inhibited NLRP3, ASC and caspase-1 expression, and alleviated the inflammatory response. In vitro, didymin reduced MI, apoptosis, inflammation and the levels of NLRP3, ASC and caspase-1 in H9C2.Discussion and conclusions Didymin prevented the deterioration of MI by inhibiting NLRP3 inflammasome in vivo and in vitro, and may be a potential natural drug for the treatment of MI. Our study provides the scientific basis for further research of didymin.

Kidney transplantation is a lifesaving procedure for patients with end-stage kidney disease (ESKD). Organs derived from donation after cardiac death (DCD) are constantly increasing; however, DCD often leads to ischaemia-reperfusion (IR) and Acute Kidney Injury (AKI) events. These phenomena increase kidney cell turnover to replace damaged cells, which are voided in urine. Urine-derived renal epithelial cells (URECs) are rarely present in the urine of healthy subjects, and their loss has been associated with several kidney disorders. The present study aimed to characterize the phenotype and potential applications of URECs voided after transplant. The results indicate that URECs are highly proliferating cells, expressing several kidney markers, including markers of kidney epithelial progenitor cells. Since the regulation of the immune response is crucial in organ transplantation and new immunoregulatory strategies are needed, UREC immunomodulatory properties were investigated. Co-culture with peripheral blood mononuclear cells (PBMCs) revealed that URECs reduced PBMC apoptosis, inhibited lymphocyte proliferation, increased T regulatory (Treg) cells and reduced T helper 1 (Th1) cells. URECs from transplanted patients represent a promising cell source for the investigation of regenerative processes occurring in kidneys, and for cell-therapy applications based on the regulation of the immune response. [ABSTRACT FROM AUTHOR]

Background: Adipose‐derived mesenchymal stem cells (ADMSCs) and their extracellular vesicles (EVs) are a promising source of therapies for ischaemia‐reperfusion (IR) because of their potent anti‐inflammatory and immunomodulatory properties. Objectives: The aims of this study were to explore the therapeutic efficacy and potential mechanism of ADMSC‐EVs in canine renal IR injury. Methods: Mesenchymal stem cells (MSCs) and EVs were isolated and characterised for surface markers. A canine IR model administered with ADMSC‐EVs was used to evaluate therapeutic effects on inflammation, oxidative stress, mitochondrial damage and apoptosis. Results: CD105, CD90 and beta integrin ITGB were positively expressed in MSCs, while CD63, CD9 and intramembrane marker TSG101 were positively expressed in EVs. Compared with the IR model group, there was less mitochondrial damage and reduction in quantity of mitochondria in the EV treatment group. Renal IR injury led to severe histopathological lesions and significant increases in biomarkers of renal function, inflammation and apoptosis, which were attenuated by the administration of ADMSC‐EVs. Conclusions: Secretion of EVs by ADMSCs exhibited therapeutic potential in renal IR injury and may lead to a cell‐free therapy for canine renal IR injury. These findings revealed that canine ADMSC‐EVs potently attenuate renal IR injury‐induced renal dysfunction, inflammation and apoptosis, possibly by reducing mitochondrial damage. [ABSTRACT FROM AUTHOR]

Necmiye &Scedil;engel,1 Zeynep Köksal,2 Ali Do&gbreve;an Dursun,3 Ömer Kurtipek,2 &Scedil;aban Cem Sezen,4 Mustafa Arslan,2 Mustafa Kavutçu5 1Department of Oral and Maxillofacial Surgery, Gazi University Faculty of Dentistry, Ankara, Turkey; 2Department of Anesthesiology and Reanimation, Gazi University Faculty of Medicine, Ankara, Turkey; 3Department of Physiology, At&inodot;l&inodot;m University Faculty of Medicine, Ankara, Turkey; 4Department of Histology and Embryology, K&inodot;r&inodot;kkale University Faculty of Medicine, K&inodot;r&inodot;kkale, Turkey; 5Department of Medical Biochemistry, Gazi University Faculty of Medicine, Ankara, TurkeyCorrespondence: Mustafa Arslan, Gazi University, Medical Faculty, Department of Anesthesiology and Reanimation, Ankara, 06510, Turkey, Tel +90 533 422 85 77, Email mustarslan@gmail.comBackground: Ischaemia–reperfusion (IR) injury, which can be encountered during surgical procedures involving the abdominal aorta, is a complex process that affects distant organs, such as the heart, liver, kidney, and lungs, as well as the lower extremities. In this study, we aimed to contribute to the limited literature by investigating the protective effect of dexmedetomidine, which was administered through different routes, on kidney tissue in rats with spinal cord IR injury.Methods: A total of 30 rats were randomly divided into five groups: control (C group), IR (IR group), IR-intraperitoneal dexmedetomidine (IRIPD group), IR-intrathecal dexmedetomidine (IRITD group), and IR-intravenous dexmedetomidine (IRIVD group). The spinal cord IR model was established. Dexmedetomidine was administered at doses of 100 μg/kg intraperitoneally, 3 μg/kg intrathecally, and 9 μg/kg intravenously. Histopathologic parameters in kidney tissue samples taken at the end of the reperfusion period and biochemical parameters in serum were evaluated.Results: When examined histopathologically, tubular dilatation was found to be significantly reduced in the IRIVD, IRITD, and IRIPD groups compared with the IR group (p = 0.012, all). Vascular vacuolization and hypertrophy were significantly decreased in the IRIVD, IRITD, and IRIPD groups compared with the IR group (p = 0.006, all). Tubular cell degeneration and necrosis were significantly reduced in the IRIVD, IRITD, and IRIPD groups compared with the IR group (p = 0.008, p = 0.08, and p = 0.030, respectively). Lymphocyte infiltration was significantly decreased in the IRIVD and IRITD groups compared with the IR group (p = 0.006 and p = 0.06, respectively).Conclusion: It was observed that dexmedetomidine administered by different routes improved the damage caused by IR in kidney histopathology. We think that the renoprotective effects of dexmedetomidine administered intravenously and intrathecally before IR in rats are greater.Keywords: dexmedetomidine, ischaemia–reperfusion, intrathecal, intravenous, rat

Abstract Epidemiological studies suggest that acute kidney injury has certain effect on myocardial function. In this study, for the first time, we tested a boron compound namely lithium tetraborate an act as an anti-oxidant and anti-inflammatory agent in ischemia-reperfusion injury. For this, we employed an in vivo rat model with kidney ischemia reperfusion injury to evaluate cardiac injury to clarify the mechanisms of lithium tetraborate. The evaluation of cardiac injury through kidney artery occlusion and reperfusion rat model indicated that lithium tetraborate could (1) reduce oxidative stress-induced endothelial dysfunction; (2) attenuate the inflammatory response of cardiac cells; and (3) alleviate the apoptosis and necrosis of myocytes. In summary, lithium tetraborate demonstrates significant therapeutic properties that contribute to the amelioration of cardiac damage, and it could be a promising candidate for future applications in myocardial dysfunction.

Testis ischaemia–reperfusion (I/R) plays a vital role in male infertility. Recent studies have demonstrated that paracrine factors of mesenchymal stem cells exert the transplanted cells' reparative effects. The present experimental study aimed to investigate the effects of conditioned medium (CM) of bone marrow‐derived mesenchymal stem cells (BMMSCs). In this study, 21 rats were separated into three groups of 7 animals: sham, I/R and I/R plus CM. Sperm parameters were measured at the end of this study. Moreover, histological parameters were examined. 2‐Deoxyuridine 5‐triphosphate nick‐end labelling (TUNEL) assay was done to assess the apoptotic cells. The count of adhered neutrophils was measured in subtunical venules. Testicular I/R led to a significant reduction in the viability and concentration of sperm and resulted in a significant elevation in the rate of abnormal sperms in comparison with sham. The CM‐treated group demonstrated a significant reduction in the rate of abnormal sperm and a significant elevation in the viability and concentration of sperm compared with the I/R group. Based on the morphometric analysis, in the I/R group, epithelial thickness and seminiferous tubule diameter significantly decreased in comparison with sham. A significant reduction was seen between the I/R and sham groups regarding the mean testicular biopsy score (MTBS) value. However, an improvement was observed in the I/R + CM group MTBS value in comparison with the I/R group. TUNEL assay showed that the apoptotic cells in the seminiferous tubules belonging to the I/R group were significantly higher compared with the control. Nevertheless, apoptotic cells were reduced in the I/R + CM group compared with the I/R group. Results of the present study showed that CM of BMMSCs exerts protective effects on the testicular I/R damages. [ABSTRACT FROM AUTHOR]

Ischaemia and reperfusion (I/R)-induced gastrointestinal disorders are caused by free radicals, resulting in organ damage and functional disarrangement. This study aimed to investigate the healing effects of hydroalcoholic extracts from the leaves of Eugenia punicifolia (Kunth) DC. (HEEP) in male and female Wistar rats with I/R-induced peptic injuries, and the role of antioxidants in improving this response. After I/R-induced gastric and duodenal injuries, male and female [intact (INT) and ovariectomized (OVZ)] rats were orally treated with HEEP for 6 days. Biochemical analysis was used to determine the catalase (CAT), superoxide dismutase (SOD), and myeloperoxidase (MPO) activities, as well as malondialdehyde and reduced glutathione levels, to measure the gastric and duodenal healing process. Six days of HEEP treatment significantly decreased the I/R-induced gastric [male (73.68%), INT (52.83%), and OVZ (43.13%)] and duodenal damage [male (57.03%), INT (56.04%), and OVZ (54.83%)] in all groups. In OVZ rats, the healing effect of HEEP occurred because of the increased activity of SOD (2x) and CAT (1.16x) in the gastric mucosa. In the duodenal mucosa of INT rats, the extract reduced MPO (20.83%) activity. The 6-day HEEP treatment improved the healing of I/R-induced peptic ulcer injury, with the system acting differently in males and females. The antioxidant system is an important component of the HEEP activity during post-I/R mucosal recovery. This result revealed the importance of antioxidant compounds in minimizing the severity of I/R-related events. [ABSTRACT FROM AUTHOR]

Abstract Background Hepatic ischaemia-reperfusion injury (HIRI) is inevitable in complicated liver surgery and is a major factor leading to postoperative complications and liver dysfunction. Studies have shown that the paracrine mechanisms of stem cell may be essential to tissue repair and functional improvement after transplantation. However, the role of the adipose-derived mesenchymal stem cell secretome (ASC-secretome) in liver regeneration in large animals remains to be determined. Methods Twenty-four miniature pigs were subjected to laparoscopic liver ischaemia-reperfusion combined with partial hepatectomy and divided into the following four groups: the saline group, the DMEM group, the ASC group and the ASC-secretome group. Serum and liver tissue samples were collected before the operation and at 1, 3 and 7 days after the operation, and changes in tissue pathology, serum inflammation, liver function, angiogenesis-related factors and liver tissue regeneration-related genes and proteins were evaluated. Results Detailed histological analysis showed that ASCs and the ASC-secretome changed pathological damage to liver tissue after liver ischaemia-reperfusion combined with partial hepatectomy (1 and 3 days: p

Objective: The aim of this study was to investigate (a) macrophage migration inhibitory factor (MIF) levels in polytrauma patients and rats after haemorrhagic shock (HS), (b) the potential of the MIF inhibitor ISO-1 to reduce multiple organ dysfunction syndrome (MODS) in acute (short-term and long-term follow-up) HS rat models and (c) whether treatment with ISO-1 attenuates NF-κB and NLRP3 activation in HS. Background: The MODS caused by an excessive systemic inflammatory response following trauma is associated with a high morbidity and mortality. MIF is a pleiotropic cytokine which can modulate the inflammatory response, however, its role in trauma is unknown. Methods: The MIF levels in plasma of polytrauma patients and serum of rats with HS were measured by ELISA. Acute HS rat models were performed to determine the influence of ISO-1 on MODS. The activation of NF-κB and NLRP3 pathways were analysed by western blot in the kidney and liver. Results: We demonstrated that (a) MIF levels are increased in polytrauma patients on arrival to the emergency room and in rats after HS, (b) HS caused organ injury and/or dysfunction and hypotension (post-resuscitation) in rats, while (c) treatment of HS-rats with ISO-1 attenuated the organ injury and dysfunction in acute HS models and (d) reduced the activation of NF-κB and NLRP3 pathways in the kidney and liver. Conclusion: Our results point to a role of MIF in the pathophysiology of trauma-induced organ injury and dysfunction and indicate that MIF inhibitors may be used as a potential therapeutic approach for MODS after trauma and/or haemorrhage. [ABSTRACT FROM AUTHOR]

ObjectiveThe aim of this study was to investigate (a) macrophage migration inhibitory factor (MIF) levels in polytrauma patients and rats after haemorrhagic shock (HS), (b) the potential of the MIF inhibitor ISO-1 to reduce multiple organ dysfunction syndrome (MODS) in acute (short-term and long-term follow-up) HS rat models and (c) whether treatment with ISO-1 attenuates NF-κB and NLRP3 activation in HS.BackgroundThe MODS caused by an excessive systemic inflammatory response following trauma is associated with a high morbidity and mortality. MIF is a pleiotropic cytokine which can modulate the inflammatory response, however, its role in trauma is unknown.MethodsThe MIF levels in plasma of polytrauma patients and serum of rats with HS were measured by ELISA. Acute HS rat models were performed to determine the influence of ISO-1 on MODS. The activation of NF-κB and NLRP3 pathways were analysed by western blot in the kidney and liver.ResultsWe demonstrated that (a) MIF levels are increased in polytrauma patients on arrival to the emergency room and in rats after HS, (b) HS caused organ injury and/or dysfunction and hypotension (post-resuscitation) in rats, while (c) treatment of HS-rats with ISO-1 attenuated the organ injury and dysfunction in acute HS models and (d) reduced the activation of NF-κB and NLRP3 pathways in the kidney and liver.ConclusionOur results point to a role of MIF in the pathophysiology of trauma-induced organ injury and dysfunction and indicate that MIF inhibitors may be used as a potential therapeutic approach for MODS after trauma and/or haemorrhage.

CD36, also known as the scavenger receptor B2, is a multifunctional receptor widely expressed in various organs. CD36 plays a crucial role in the uptake of long-chain fatty acids, the main metabolic substrate in myocardial tissue. The maturation and transportation of CD36 is regulated by post-translational modifications, including phosphorylation, ubiquitination, glycosylation, and palmitoylation. CD36 is decreased in pathological cardiac hypertrophy caused by ischaemia–reperfusion and pressure overload, and increased in diabetic cardiomyopathy and atherosclerosis. Deficiency of CD36 alleviates diabetic cardiomyopathy and atherosclerosis, while overexpression of CD36 eliminates ischaemia–reperfusion damage, together suggesting that CD36 is closely associated with the progression of cardiovascular diseases and may be a new therapeutic target. This review summarizes the regulation and post-translational modifications of CD36 and evaluates its role in cardiovascular diseases and its potential as a therapeutic target. [ABSTRACT FROM AUTHOR]

Spinal cord injury (SCI), a major cause of disability, causes high global disease and economic burdens. Stress‐induced phosphoprotein 1 (STIP1) has been identified to be involved in spinal cord ischaemia‐reperfusion injury (SCII); however, the effect of STIP1 on SCII remains unclear until now. This study aimed to examine the role of STIP1 in SCII and unravel the possible mechanisms. Western blotting and immunohistochemical staining showed that STIP1 expression rapidly increased and then decreased in rat spinal cord following SCII treatment. Neurological function scoring, HE staining, immunohistochemical staining and Western blotting revealed that STIP1 overexpression alleviated SCII‐induced motor dysfunction of hind limbs, neuronal loss and inflammation in spinal cord, and inhibited activity of nuclear factor kappa B (NF‐κB) signalling in rats. Immunoprecipitation identified that STIP1 was co‐located with Iba‐1. In addition, STIP1 was found to ameliorate oxygen and glucose deprivation (OGD)‐induced inflammation and activation of NF‐κB signalling in mouse microglia BV2 cells, and STIP1 resulted in decrease of heat shock protein family A member 8 (HSPA8), increase of IκBβ expression and reduced binding of IκBβ to HSPA8 in BV2 cells. The results of the present study demonstrate that STIP1 alleviates ischaemia/reperfusion‐induced neuronal injury and inflammation in rat spinal cord and mouse microglial cells by deactivating NF‐κB signalling. These findings may provide novel insights for the clinical diagnosis and treatment of SCI. [ABSTRACT FROM AUTHOR]

Objective LncRNA Fendrr plays an important role in cardiac development, but its role in myocardial ischaemia-reperfusion (I/R) injury remains unclear. P53 has been shown to be an important regulator of apoptosis and is involved in myocardial I/R-induced apoptosis. This study aims at investigating whether Fendrr affects hypoxia/reoxygenation (H/R)-induced cardiomyocyte apoptosis through p53. Methods The left anterior descending coronary artery of the rat was ligated for 30 min and then reperfusion for 120 min by releasing the suture. Neonatal rat ventricular myocytes (NRVM) and rat cardiac cell line H9c2 were cultured for 6 h in hypoxia (95% N2 and 5% CO2), followed by reoxygenation (95% air and 5% CO2) for 6 h. Transfection were performed in cells. Apoptosis was detected by flow cytometry. Moreover, RNA pull-down, RNA immunoprecipitation, ubiquitination assay, GST pull-down assay and co-immunoprecipitation were used to detect the regulation of Fendrr on p53 protein. Key findings Fendrr was decreased in I/R-induced myocardium and H/R-induced cardiomyocyte, and overexpression of Fendrr inhibited H/R-induced NRVM or H9c2 cells apoptosis. Further research found that the 1381-2100 nt of Fendrr bound to p53 protein and Fendrr promoted t direct binding of p53 to Cop1. The inhibition of Fendrr reduced the binding of E3 ubiquitin-protein ligase constitutive photomorphogenesis protein 1 (COP1) to p53 and reduced the ubiquitination of p53. Furthermore, the inhibition of Fendrr on H/R-induced NRVM or H9c2 cells apoptosis could be reversed by overexpression of p53. Conclusions Fendrr can inhibit H/R-induced cardiomyocyte apoptosis, which is partly through promoting the ubiquitination and degradation of p53 by increasing the binding of Cop1 and p53. [ABSTRACT FROM AUTHOR]

Renal ischaemia-reperfusion (IR) is a major cause of acute kidney injury (AKI). Cold-inducible RNA-binding protein (CIRBP) may contribute to AKI because its deficiency protects against renal IR injury in a mechanism believed to involve ferroptosis. We aimed to investigate whether ferroptosis is associated with CIRBP-mediated renal damage. The differential expression of CIRBP was examined in tubular epithelial (HK2) cells during hypoxia-reoxygenation (HR) or in response to erastin, an inducer of ferroptosis. CIRBP expression was increased in response to HR or erastin in HK2 cells but the silencing of CIRBP inhibited HR and erastin-induced ferroptosis together with ferritinophagy. We discovered an interaction between CIRBP and ELAVL1 using STRING software, which was verified through co-immunoprecipitation and fluorescence colocalization assays. We found that ELAVL1 is a critical regulator in the activation of ferritinophagy and the promotion of ferroptosis. HR or erastin also induced the expression of ELAVL1. An autophagy inhibitor (hydroxychloroquine) or si-ELAVL1 transfection reversed CIRBP-enhanced ferritinophagy activation and ferroptosis in HK2 cells under HR. Injection of anti-CIRBP antibody into a mouse model of IR inhibited ferroptosis and decreased renal IR injury in vivo. In summary, our results provide evidence that ferritinophagy-mediated ferroptosis could be responsible for CIRBP-enhanced renal IR injury. [ABSTRACT FROM AUTHOR]

Purpose. The aim of our study was to analyse the effect of a single-cycle ischaemic preconditioning (IPC) protocol on performance in the 100-m front crawl swimming modality. Methods. Overall, 16 swimmers were recruited: 8 female athletes (12.9 ± 0.88 years) and 8 male athletes (13.1 ± 0.88 years). In a randomized crossover design, all participants performed a 100-m front crawl sprint preceded by an IPC or placebo cycle. In the IPC trial, a pneumatic cuff was attached to the proximal thigh and was inflated at a pressure equivalent to 80% of arterial occlusion and remained inflated for 5 min (ischaemia); in the placebo trial, the cuff remained inflated for the same amount of time, but at low external pressure levels (20 mm Hg). The volunteers started the test 5 min after cuff pressure release (reperfusion). Results. It was not possible to verify significant differences within the time (seconds) required to complete the test between the IPC and placebo interventions (75.68 ± 7.2 and 75.75 ± 8.1 s, respectively; p = 0.916). Conclusions. Therefore, we can conclude that the tested IPC protocol does not seem to be sufficient to provide performance improvement in 100-m front crawl in young athletes. [ABSTRACT FROM AUTHOR]

Nuclear receptor subfamily 4, group A, member 1 (NR4A1) can aggravate ischaemia‐reperfusion (I/R) injury in the heart, kidney and brain. Thus, the present study aimed to unravel the role of NR4A1 on hepatic I/R injury. For this purpose, the mouse hepatic I/R model and H/R‐exposed mouse hepatocytes model were established to stimulate the hepatic and hepatocellular damage. Then, the levels of ALT and AST as well as TNF‐α and IL‐1β expression were measured in the mouse serum and supernatant of hepatocyte s, respectively. Thereafter, we quantified the levels of NR4A1, CYR61, NF‐kB p65 and TGFβ1 under pathological conditions, and their interactions were analysed using ChIP and dual‐luciferase reporter gene assays. The in vivo and in vitro effects of NR4A1, CYR61, NF‐kB p65 and TGFβ1 on I/R‐induced hepatic and H/R‐induced hepatocellular damage were evaluated using gain‐ and loss‐of‐function approaches. NR4A1 was up‐regulated in the hepatic tissues of I/R‐operated mice and in H/R‐treated hepatocytes. Silencing NR4A1 relieved the I/R‐induced hepatic injury, as supported by suppression of ALT and AST as well as TNF‐α and IL‐1β. Meanwhile, NR4A1 knockdown attenuated the H/R‐induced hepatocellular damage by inhibiting the apoptosis of hepatocyte s. Moreover, we also found that NR4A1 up‐regulated the expression of CYR61 which resulted in the activation of the NF‐κB signalling pathway, thereby enhancing the transcription of TGFβ1, which was validated to be the mechanism underlying the contributory role of NR4A1 in hepatic I/R injury. Taken together, NR4A1 silencing reduced the expression of CYR61/NF‐κB/TGFβ1, thereby relieving the hepatic I/R injury. [ABSTRACT FROM AUTHOR]

This study was performed to evaluate the effect of liraglutide on experimental testicular ischaemia reperfusion in rats in terms of biochemistry, histopathology and immunohistochemistry. A total of 28 male Wistar‐Albino rats were divided randomly into 4 groups: control (7), sham (7), ischaemia‐reperfusion (7) and ischaemia‐reperfusion + liraglutide (7). Biochemically, Nitric Oxide, Malondialdehyde, Superoxide dismutase, Glutathione peroxidase and Catalase levels were measured in the testis. Apoptosis protease activating factor‐1 and inducible nitric oxide synthase activity were evaluated immunohistochemically as well. Statistical analyses were made via the Kruskal–Wallis and Mann–Whitney U tests. In the reperfusion group, CAT and SOD values were increased (p >.05), NO and MDA values were decreased (p <.05) after administration of liraglutide. In addition, GPx values were significantly increased in ischaemia reperfusion + liraglutide administered group compared to reperfusion group (p <.05). Apaf‐1 and iNOS activity were significantly decreased with the addition of liraglutide treatment to the ischaemia‐reperfusion group (p <.05). First of all, we would like to say that liraglutide treatment is moderately preventive against I/R injury in testicular torsion. The anti‐inflammatory, antioxidant and antiapoptotic properties of liraglutide are create a moderately protective effect as we show in this study. [ABSTRACT FROM AUTHOR]

Open in new tab Download slide Open in new tab Download slide OBJECTIVES Endothelial dysfunction during ischaemia-reperfusion (IR) is a major cause of primary graft dysfunction during lung transplantation. The routine use of cardiopulmonary bypass (CPB) during lung transplantation remains controversial. However, the contribution of CPB to pulmonary endothelial dysfunction remains unclear. The objective was to investigate the impact of CPB on endothelial dysfunction in a lung IR rat model. METHODS Rats were allocated to 4 groups: (i) Sham, (ii) IR, (iii) CPB and (iv) IR-CPB. The primary outcome was the study of pulmonary vascular reactivity by wire myograph. We also assessed glycocalyx degradation by enzyme-linked immunosorbent assay and electron microscopy and both systemic and pulmonary inflammation by enzyme-linked immunosorbent assay and immunohistochemistry. Rats were exposed to 45 min of CPB and IR. We used a CPB model allowing femoro-femoral support with left pulmonary hilum ischaemia for IR. RESULTS Pulmonary endothelium-dependent relaxation to acetylcholine was markedly reduced in the IR-CPB group (10.7 ± 9.1%) compared to the IR group (50.5 ± 5.2%, P  < 0.001), the CPB group (54.1 ± 4.7%, P  < 0.001) and the sham group (80.8 ± 6.7%, P  < 0.001), suggesting that the association of pulmonary IR and CPB increases endothelial dysfunction. In IR-CPB, IR and CPB groups, vasorelaxation was completely abolished when inhibiting nitric oxide synthase, suggesting that this relaxation process was mainly mediated by nitric oxide. We observed higher syndecan-1 plasma levels in the IR-CPB group in comparison with the other groups, reflecting an increased degradation of glycocalyx. We also observed higher systemic inflammation in the IR-CPB group as shown by the increased plasma levels of IL-1β, IL-10. CONCLUSIONS CPB significantly increased the IR-mediated effects on pulmonary endothelial dysfunction. Therefore, the use of CPB during lung transplantation could be deleterious, by increasing endothelial dysfunction. [ABSTRACT FROM AUTHOR]

Ischaemia-reperfusion (I/R) injury is a serious problem subsequent to reperfusion treatment for ovarian torsion. The role of nitric oxide (NO) in ovarian I/R injury is debatable. The main focus of this study was to explore the protective role of L-arginine, a potent NO precursor, on ovarian I/R injury. Female Wistar rats were divided into three groups (n = 5). In the control group, only laparotomy was performed. In the I/R group, ischaemia and reperfusion were performed and no drug was given. In the I/R + arginine group, ischaemia was followed by reperfusion and 200 mg kg-1 L-arginine was injected 5 min before reperfusion. Concentration of malondialdehyde, NO and reduced glutathione, as well as activity of superoxide dismutase and catalase were analyzed. Hematoxylin and eosin-stained slides were microscopically examined for histological evaluation of the ovaries. Superoxide dismutase and catalase activity along with concentration of reduced glutathione and NO were significantly lower in the I/R group in comparison to the control group. Malondialdehyde concentration was significantly higher in the I/R group than in control group. These results were reversed with supplementation of L-arginine. Light microscopic examination revealed severe vascular congestion, edema, haemorrhage, and follicular degeneration in the ovary tissue. The extent of ovarian damage was much higher in the I/R group than in the I/R + L-arginine group. Treatment with L-arginine seems to have an ameliorating effect against oxidative stress in I/R injury in rat ovary. It considerably reduced the altered histological changes in the ovaries. Thus, it can be speculated that L-arginine might play a pivotal role as a potent therapeutic agent against ovarian torsion. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the role of farnesoid X receptor (FXR), a ligand‐dependent transcription factor, in renal ischaemia‐reperfusion (I/R) injury. Materials and Methods: We performed unilateral renal I/R model in FXR knockout (Fxr−/−) and wild‐type (WT) mice in vivo and a hypoxia‐reoxygenation (H/R) model in vitro. The pathways by which FXR induces apoptosis were detected using a proteome profiler array. The effects of FXR on apoptosis were evaluated using immunoblotting, TUNEL assays and flow cytometry. Results: Compared with WT mice, Fxr−/− mice showed improved renal function and reduced tubular injury scores and apoptosis. Consistent with the in vivo results, the silencing of FXR decreased the number of apoptotic HK‐2 cells after H/R, while FXR overexpression aggravated apoptosis. Notably, bone marrow transplantation (BMT) and immunohistochemistry experiments revealed the involvement of FXR in the tubular epithelium rather than in inflammatory cells. Furthermore, in vivo and in vitro studies demonstrated that FXR deficiency increased phosphorylated Bcl‐2 agonist of cell death (p‐Bad) expression levels and the ratio of Bcl‐2/Bcl‐xL to Bax expression in the kidney. Treatment with wortmannin, which reduced p‐Bad expression, inhibited the effects of FXR deficiency and eliminated the tolerance of Fxr−/− mouse kidneys to I/R injury. Conclusions: These results established the pivotal importance of FXR inactivation in tubular epithelial cells after I/R injury. FXR may promote the apoptosis of renal tubular epithelial cells by inhibiting PI3k/Akt‐mediated Bad phosphorylation to cause renal I/R damage. [ABSTRACT FROM AUTHOR]

Objective: Previous studies indicate that eosinophils are recruited into the allograft following orthotopic liver transplantation and protect from ischaemia reperfusion (IR) injury. In the current studies, we aim to explore whether their protective function could outlast during liver repair., Design: Eosinophil-deficient mice and adoptive transfer of bone marrow-derived eosinophils (bmEos) were employed to investigate the effects of eosinophils on tissue repair and regeneration after hepatic IR injury. Aside from exogenous cytokine or neutralising antibody treatments, mechanistic studies made use of a panel of mouse models of eosinophil-specific IL-4/IL-13-deletion, cell-specific IL-4rα-deletion in liver macrophages and hepatocytes and macrophage-specific deletion of heparin-binding epidermal growth factor-like growth factor (hb-egf)., Result: We observed that eosinophils persisted over a week following hepatic IR injury. Their peak accumulation coincided with that of hepatocyte proliferation. Functional studies showed that eosinophil deficiency was associated with a dramatic delay in liver repair, which was normalised by the adoptive transfer of bmEos. Mechanistic studies demonstrated that eosinophil-derived IL-4, but not IL-13, was critically involved in the reparative function of these cells. The data further revealed a selective role of macrophage-dependent IL-4 signalling in liver regeneration. Eosinophil-derived IL-4 stimulated macrophages to produce HB-EGF. Moreover, macrophage-specific hb-egf deletion impaired hepatocyte regeneration after IR injury., Conclusion: Together, these studies uncovered an indispensable role of eosinophils in liver repair after acute injury and identified a novel crosstalk between eosinophils and macrophages through the IL-4/HB-EGF axis., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Competing Interests: Competing interests: None declared.

Myocardial infarction (MI) is a disease of major consequence in the modern world, causing permanent, irreversible damage to the heart. Survivors are at risk for developing further cardiovascular pathologies such as heart failure. Further study of MI injury is crucial to improve the understanding and treatment of the post-MI heart. The most commonly used model for MI in vivo is surgical ligation of the left anterior descending coronary artery (LAD). There are two predominant approaches: permanent ligation (PL), where the LAD is permanently occluded with a suture, or ischaemia-reperfusion (IR), where the LAD is temporarily occluded before removing the suture to restore blood flow and tissue reperfusion. PL results in the majority of the area at risk becoming infarcted, leading to significant apoptotic cell death and a large scar. Conversely, IR salvages some of the area at risk; thus, the scar is smaller and includes reperfusion injury, an additional, albeit smaller, second wave of necrotic damage. PL may be a more appropriate model choice for studies of heart tissue injury and wound healing, owing to the larger, more consistent infarcts, while IR enables the study of reperfusion injury. Both are clinically relevant, and the choice of model depends upon the precise pre-clinical research questions to be addressed.

Background: Hepatic ischaemia-reperfusion injury (HIRI) is inevitable in complicated liver surgery and is a major factor leading to postoperative complications and liver dysfunction. Studies have shown that the paracrine mechanisms of stem cell may be essential to tissue repair and functional improvement after transplantation. However, the role of the adipose-derived mesenchymal stem cell secretome (ASC-secretome) in liver regeneration in large animals remains to be determined. Methods: Twenty-four miniature pigs were subjected to laparoscopic liver ischaemia-reperfusion combined with partial hepatectomy and divided into the following four groups: the saline group, the DMEM group, the ASC group and the ASC-secretome group. Serum and liver tissue samples were collected before the operation and at 1, 3 and 7 days after the operation, and changes in tissue pathology, serum inflammation, liver function, angiogenesis-related factors and liver tissue regeneration-related genes and proteins were evaluated. Results: Detailed histological analysis showed that ASCs and the ASC-secretome changed pathological damage to liver tissue after liver ischaemia-reperfusion combined with partial hepatectomy (1 and 3 days: p < 0.01). Compared with the saline and DMEM control groups, the ASC-secretome group had significantly reduced expression levels of ALP (1 and 3 days: p < 0.05), ALT (1 day: p < 0.01; 3 days: p < 0.05) and AST (1 and 3 days: p < 0.01), which promoted the recovery of liver function. Moreover, detection of the expression levels of TNF-α and IL-1β (1 day: p < 0.01; 3 days: p < 0.05), IL-6 (1 and 3 days: p < 0.05) and IL-10 (1 and 3 days: p < 0.01) in serum confirmed that the ASC-secretome had obvious anti-inflammatory effects. In addition, the ASC-secretome increased the expression levels of ANG-1 (3 days: p < 0.01), ANG-2 (3 and 7 days: p < 0.01) and VEGF (1 and 7 days: p < 0.05; 3 days: p < 0.01) and promoted angiogenesis during liver regeneration. Moreover, it promoted the mRNA expression of HGF and Cyclin D1 (1 and 3 days: p < 0.01); increased the levels of p-STAT3 (1 and 3 days: p < 0.01), PCNA and Ki67 (1 and 3 days: p < 0.01; 7 days: p < 0.05); inhibited the negative feedback of SOCS3 (1 and 3 days: p < 0.01); and decreased the mRNA expression of TGF-β (3 days: p < 0.01). The cytokines and growth factors detected in the ASC-secretome included TNF-α, IL-6, IL-1β, ANG-1, ANG-2, VEGF and b-FGF. Conclusion: The ASC-secretome alleviates the inflammatory response induced by ischaemia-reperfusion combined with partial hepatectomy in miniature pigs and promotes liver regeneration. [ABSTRACT FROM AUTHOR]

Hypertension is the most important modifiable risk factor for stroke and is associated with poorer post-stroke outcomes. The antioxidant uric acid is protective in experimental normotensive ischaemic stroke. However, it is unknown whether this treatment exerts long-term protection in hypertension. We aimed to evaluate the impact of transient intraluminal middle cerebral artery (MCA) occlusion (90 min)/reperfusion (1–15 days) on brain and vascular damage progression in adult male Wistar-Kyoto (WKY; n = 36) and spontaneously hypertensive (SHR; n = 37) rats treated (i.v./120 min post-occlusion) with uric acid (16 mg kg−1) or vehicle (Locke's buffer). Ischaemic brain damage was assessed longitudinally with magnetic resonance imaging and properties of MCA from both hemispheres were studied 15 days after stroke. Brain lesions in WKY rats were associated with a transitory increase in circulating IL-18 and cerebrovascular oxidative stress that did not culminate in long-term MCA alterations. In SHR rats, more severe brain damage and poorer neurofunctional outcomes were coupled to higher cortical cerebral blood flow at the onset of reperfusion, a transient increase in oxidative stress and long-lasting stroke-induced MCA hypertrophic remodelling. Thus, stroke promotes larger brain and vascular damage in hypertensive rats that persists for long-time. Uric acid administered during early reperfusion attenuated short- and long-term brain injuries in both normotensive and hypertensive rats, an effect that was associated with abolishment of the acute oxidative stress response and prevention of stroke-induced long-lasting MCA remodelling in hypertension. These results suggest that uric acid might be an effective strategy to improve stroke outcomes in hypertensive subjects. [ABSTRACT FROM AUTHOR]

Testicular torsion is an emergency, and unless there is an urgent intervention, irreversible ischaemic damage and gonad loss occur in the testicle. We aimed to investigate myricetin's antioxidant properties as well as its protective effect against ischaemia–reperfusion (I/R) damage in the testicular torsion model. A total of 18 rats were divided into three equal groups. Group 1 was the sham group. Group 2: testicular torsion was performed, and orchiectomy was done 2 hr after detorsion. Group 3: received torsion and 1 mg/kg intraperitoneal myricetin was given 30 min before detorsion, and orchiectomy was applied 2 hr after detorsion. We evaluated tissue malondialdehyde, superoxide dismutase, and catalase levels and Johnsen Testicular Biopsy Score to show its histopathological effect. There was a statistically significant decrease in MDA values in myricetin group compared to Group 2 (p <.017). There was no significant difference in the statistical analysis of SOD and CAT values (p =.337 and p =.025). There was a statistically significant difference in testicular I/R damage in the myricetin group compared to Group 1 and Group 2 (p <.017). Myricetin treatment significantly decreased testicular tissue damage compared to the torsion group but did not reach the values close to the control group. [ABSTRACT FROM AUTHOR]

This study was performed to investigate the protective effects of royal jelly (RJ) on a testicular torsion‐induced ischaemia/reperfusion (I/R) injury in adult rats. A total of 40 male Wistar rats were divided into four groups, including 10 rats in each group: Group 1 (sham), Group 2 (Control), group 3 (I/R rats treated with 100 mg/kg RJ for 50 days after torsion) and group 4(I/R rats treated with 20 mg/kg vitamin C for 50 days after torsion). Testicular torsion was created by rotating the right testes 720° a clockwise direction for 90 min. The levels of testosterone were measured by ELISA. Pathological evaluation, mean maturity and quality of the seminiferous tubules were used. Results showed that the testicular histopathology standards and testosterone levels changes were statistically significant in groups 3 and 4. The results obtained in this study may suggest that RJ like vitamin C had protective effects on a testicular ischaemia/reperfusion‐induced injury in rats. [ABSTRACT FROM AUTHOR]

Objective: LncRNA Fendrr plays an important role in cardiac development, but its role in myocardial ischaemia–reperfusion (I/R) injury remains unclear. P53 has been shown to be an important regulator of apoptosis and is involved in myocardial I/R‐induced apoptosis. This study aims at investigating whether Fendrr affects hypoxia/reoxygenation (H/R)‐induced cardiomyocyte apoptosis through p53. Methods: The left anterior descending coronary artery of the rat was ligated for 30 min and then reperfusion for 120 min by releasing the suture. Neonatal rat ventricular myocytes (NRVM) and rat cardiac cell line H9c2 were cultured for 6 h in hypoxia (95% N2 and 5% CO2), followed by reoxygenation (95% air and 5% CO2) for 6 h. Transfection were performed in cells. Apoptosis was detected by flow cytometry. Moreover, RNA pull‐down, RNA immunoprecipitation, ubiquitination assay, GST pull‐down assay and co‐immunoprecipitation were used to detect the regulation of Fendrr on p53 protein. Key findings: Fendrr was decreased in I/R‐induced myocardium and H/R‐induced cardiomyocyte, and overexpression of Fendrr inhibited H/R‐induced NRVM or H9c2 cells apoptosis. Further research found that the 1381–2100 nt of Fendrr bound to p53 protein and Fendrr promoted t direct binding of p53 to Cop1. The inhibition of Fendrr reduced the binding of E3 ubiquitin–protein ligase constitutive photomorphogenesis protein 1 (COP1) to p53 and reduced the ubiquitination of p53. Furthermore, the inhibition of Fendrr on H/R‐induced NRVM or H9c2 cells apoptosis could be reversed by overexpression of p53. Conclusions: Fendrr can inhibit H/R‐induced cardiomyocyte apoptosis, which is partly through promoting the ubiquitination and degradation of p53 by increasing the binding of Cop1 and p53. [ABSTRACT FROM AUTHOR]

Ranolazine is a drug used in refractory chronic stable angina. In this study, it was aimed to evaluate the protective effect of ranolazine in a testis torsion model in light of objective biochemical and pathological data. A total of 24 pre‐pubertal male Wistar albino rats were separated into three groups of 8 as the sham group, control group and ranolazine group. Testis torsion was applied for 3 hr to all the rats in Group Control and Group Ranolazine. In Group Control, 0.9% NaCl was applied 1 hr after the torsion. In Group Ranolazine, ranolazine 30 mg/kg was dissolved in a 0.9% NaCl solution and was administered intraperitoneally 1 hr after torsion. Histopathological evaluation was made using the Cosentino score. As a result of the objective biochemical and pathological criteria used in this study, this protective effect of ranolazine was observed in testis torsion. The results obtained in this study may suggest that ranolazine is a drug that could be applied after detorsion to patients diagnosed with torsion. [ABSTRACT FROM AUTHOR]