The activated caveolin-3/µ-opioid receptor complex drives morphine-induced rescue therapy in failing hearts.

BACKGROUND AND PURPOSE: Opioid analgesics can alleviate ischaemia/reperfusion (I/R) injury in chronic heart failure. However, the underlying mechanisms and targets remain unknown. Here, we investigate if caveolin-3 (Cav3) interacts with µ opioid receptors and if Cav3-µ receptor interactions play a role in morphine-induced cardioprotection in failing hearts. EXPERIMENTAL APPROACH: Cav3 and µ receptor proteins in human and rat heart tissue were determined by western blot, immunofluorescence and co-immunoprecipitation. Methyl-ß-cyclodextrin (MßCD), a destroyer of caveolae, and AAV-Cav3 shRNA were used to reduce Cav3 expression in failing rat hearts. CTOP, a specific µ antagonist, was administrated before morphine preconditioning in perfused failing heart models of myocardial I/R injury. KEY RESULTS: Levels of Cav3 and µ receptor proteins were significantly higher in human and rat myocardial tissues with heart failure than in control tissues. Cav3 and µ receptor expression levels were positively correlated with disease severity. The signal of the cardiac Cav3 protein was colocalized with µ receptor in both the human and rat heart sections. Disruption of caveolae in the failing heart by either MßCD or AAV-Cav3 shRNA significantly inhibits morphine-induced phosphorylation of ERK1/2 and cardioprotection. Administration of CTOP substantially reduced Cav3 expression and morphine-induced cardioprotective effect in heart failure. CONCLUSION AND IMPLICATIONS: Our data suggest that up-regulation of the Cav3/µ receptor complex is critical for morphine protection of the failing heart against I/R injury by regulating the ERK1/2 pathway. The activated Cav3/µ receptor complex is an understudied therapeutic target for opioid treatment of heart failure and ischaemic insult.

CBR-470-1 protects against cardiomyocyte death in ischaemia/reperfusion injury by activating the Nrf2-GPX4 cascade.

Cardiac ischaemia/reperfusion (I/R) impairs mitochondrial function, resulting in excessive oxidative stress and cardiomyocyte ferroptosis and death. Nuclear factor E2-related factor 2 (Nrf2) is a key regulator of redox homeostasis and has cardioprotective effects against various stresses. Here, we tested whether CBR-470-1, a noncovalent Nrf2 activator, can protect against cardiomyocyte death caused by I/R stress. Compared with vehicle treatment, the administration of CBR-470-1 (2 mg/kg) to mice significantly increased Nrf2 protein levels and ameliorated the infarct size, the I/R-induced decrease in cardiac contractile performance, and the I/R-induced increases in cell apoptosis, ROS levels, and inflammation. Consistently, the beneficial effects of CBR-470-1 on cardiomyocytes were verified in a hypoxia/reoxygenation (H/R) model in vitro, but this cardioprotection was dramatically attenuated by the GPX4 inhibitor RSL3. Mechanistically, CBR-470-1 upregulated Nrf2 expression, which increased the expression levels of antioxidant enzymes (NQO1, SOD1, Prdx1, and Gclc) and antiferroptotic proteins (SLC7A11 and GPX4) and downregulated the protein expression of p53 and Nlrp3, leading to the inhibition of ROS production and inflammation and subsequent cardiomyocyte death (apoptosis, ferroptosis and pyroptosis). In summary, CBR-470-1 prevented I/R-mediated cardiac injury possibly through inhibiting cardiomyocyte apoptosis, ferroptosis and pyroptosis via Nrf2-mediated inhibition of p53 and Nlrp3 and activation of the SLC7A11/GPX4 pathway. Our data also highlight that CBR-470-1 may serve as a valuable agent for treating ischaemic heart disease.

Ulinastatin attenuated cardiac ischaemia/reperfusion injury by suppressing activation of the tissue kallikrein-kinin system.

BACKGROUND AND PURPOSE: Ulinastatin has beneficial effects in patients undergoing coronary artery bypass grafting (CABG) surgery due to its anti-inflammatory properties, but the underlying mechanism remains unclear. EXPERIMENTAL APPROACH: We used samples from patients undergoing CABG, a model of cardiac ischaemia-reperfusion injury (IRI) in mice and murine cardiac endothelial cell cultures to investigate links between ulinastatin, the kallikrein-kinin system (KKS), endothelial dysfunction and cardiac inflammation in the response to ischaemia/reperfusion injury (IRI). These links were assessed using clinical investigations, in vitro and in vivo experiments and RNA sequencing analysis. KEY RESULTS: Ulinastatin inhibited the activity of tissue kallikrein, a key enzyme of the KKS, at 24 h after CABG surgery, which was verified in our murine cardiac ischaemia-reperfusion model. Under normal conditions, ulinastatin only inhibited kallikrein activity but did not affect bradykinin (B1/B2) receptors. Ulinastatin protected against IRI, in vivo and in vitro, by suppressing activation of the kallikrein-kinin system and down-regulating B1/B2 receptor-related signalling pathways including ERK/ iNOS, which resulted in enhanced endothelial barrier function, mitigation of inflammation and oedema, decreased infarct size, improved cardiac function and decreased mortality. Inhibition of kallikrein and knockdown of B1, but not B2 receptors prevented ERK translocation into the nucleus, reducing reperfusion-induced injury in murine cardiac endothelial cells. CONCLUSIONS AND IMPLICATIONS: Treatment with ulinastatin exerts a protective influence on cardiac reperfusion by suppressing activation of the kallikrein-kinin system. Our findings highlight the potential of targeting kallikrein /bradykinin receptors to alleviate endothelial dysfunction, thus improving cardiac IRI.

Hydrogen attenuates ischaemia-reperfusion injury in skeletal muscles post-limb replantation by activating the NRF2/HO-1 signalling pathway to reduce BAX expression.

Background: Ischaemia-reperfusion injury (IRI) is a critical complication post-limb replantation. The oxidative stress and cellular apoptosis due to IRI considerably hinder the healing process. This study aimed to investigate the modulatory effects of pre-perfusion with hydrogen-rich heparin sodium on the nuclear factor erythroid 2-related factor 2 (NRF2)/haeme oxygenase-1 (HO-1) pathway and its potential mechanisms in mitigating skeletal muscle IRI post-limb replantation. Methods: Forty healthy Sprague-Dawley rats (250-300 g) were classified into five groups (n = 8 each): normal control, IRI + heparin sodium pre-perfusion (heparin group), IRI + hydrogen-rich heparin sodium pre-perfusion (hydrogen-rich heparin group), IRI + hydrogen-rich heparin sodium pre-perfusion + NRF2 inhibitor (hydrogen-rich heparin + all-trans retinoic acid [ATRA] group), and IRI + heparin sodium pre-perfusion + NRF2 inhibitor (heparin + ATRA group). The activation of the NRF2/HO-1 pathway in skeletal muscle IRI was evaluated based on HO-1 expression using western blotting and immunofluorescence. Furthermore, haematoxylin and eosin staining and transmission electron microscopy were employed to determine the histopathological characteristics. Additionally, superoxide dismutase and malondialdehyde levels in skeletal muscle tissue were measured to assess antioxidant capacity and the degree of oxidative stress damage. Tissue hypoxia was assessed based on hypoxia-inducible factor 1-alpha expression, whereas apoptosis markers BCL-2-associated X protein (BAX) and Caspase-3 in skeletal muscle tissues were analysed using western blotting with terminal deoxynucleotidyl transferase dUTP nick end labelling staining to quantify cell apoptosis. Results: Compared with the control group, the heparin group exhibited significant pathological changes, including inflammatory infiltration and cellular hypertrophy, with increased apoptosis and oxidative stress. Notably, NRF2 suppression aggravated these effects. However, hydrogen-rich heparin sodium prominently activated the NRF2/HO-1 pathway, enhancing antioxidant defence and reducing BAX/Caspase-3-mediated apoptosis, thereby mitigating IRI-induced damage. The use of an NRF2 inhibitor to inhibit NRF2 excitation by hydrogen-rich heparin sodium notably weakened NRF2 activation and the antioxidant response, resulting in a substantial increase in cellular apoptosis. Conclusion: Pre-perfusion with hydrogen-rich heparin sodium markedly diminishes the BAX/Caspase-3-mediated apoptotic pathway in skeletal muscle tissues with IRI through the excitation of the NRF2/HO-1 pathway.

SEA Alleviates Hepatic Ischaemia-Reperfusion Injury by Promoting M2 Macrophage Polarisation.

Hepatic ischaemia-reperfusion (I/R) injury is a frequent and nearly inevitable pathophysiological process without widely accepted effective therapy. Soluble egg antigen (SEA) of Schistosoma japonicum (S. japonicum) is the main mediators capable of regulating immunological activities and has received increased attention in immune-mediated diseases. But its role in hepatic I/R injury has not been well defined. This study aimed to elucidate whether SEA protects liver against hepatic I/R injury and explore underlying mechanism. After intraperitoneal injecting SEA three times a week for 4 weeks, mice underwent 70% hepatic I/R injury. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), haematoxylin-eosin (HE) and TdT-mediated dUTP nick-end labelling (TUNEL) staining were used to evaluate liver injury. The severity related to the inflammatory response was also investigated. Furthermore, immunofluorescence was used to detect macrophage polarisation. Compared with the hepatic I/R injury group, SEA pretreatment significantly alleviated hepatic I/R injury induced liver damage, apoptosis and inflammatory. Interestingly, SEA enhanced the polarisation of macrophages towards M2 macrophages in vivo. We are the first to investigate the therapeutic efficacy of S. japonicum SEA in a hepatic I/R injury model in mice. We provided the first direct evidence that SEA attenuated hepatic I/R injury by promoting M2 macrophage polarisation.

Hypomethylated leptin receptor reduces cerebral ischaemia-reperfusion injury by activating the JAK2/STAT3 signalling pathway.

OBJECTIVE: To investigate the cerebroprotective effects of leptin in vitro and in vivo via the Janus kinase-2 (JAK2)/transcription factor signal transducer and activators of transcription-3 (STAT3) pathway and leptin receptors (LEPR). METHODS: The study used the cellular oxygen-glucose deprivation (OGD) model in PC12 cells and the middle cerebral artery occlusion (MCAO) rat model of cerebral ischaemia-reperfusion injury (CIRI) to assess changes in gene expression and protein levels following leptin pretreatment. The methylated DNA immunoprecipitation (MeDIP) assay measured DNA methylation levels. RESULTS: The optimal leptin concentration for exerting neuroprotective effects against ischaemia-reperfusion injury in PC12 cells was 200 ng/ml in vitro, but excessive leptin diminished this effect. Leptin pretreatment in the MCAO rat model demonstrated a similar effect to previously reported leptin administration post-CIRI. In addition to regulating the expression of inflammation-related cytokines, Western blot analysis showed that leptin pretreatment upregulated BCL-2 and downregulated caspase 3 levels. The MeDIP analysis demonstrated that DNA methylation regulated LEPR gene expression in the MCAO rat model when leptin pretreatment was used. CONCLUSION: Exogenous leptin might bind to extra-activated LEPR by reducing the methylation level of the LEPR gene promoter region, which leads to an increase in phosphorylated JAK2/STAT3 and apoptotic signalling pathways.

Jun-activated SOCS1 enhances ubiquitination and degradation of CCAAT/enhancer-binding protein ß to ameliorate cerebral ischaemia/reperfusion injury.

This study investigates the molecular mechanisms behind ischaemia/reperfusion (I/R) injury in the brain, focusing on neuronal apoptosis. It scrutinizes the role of the Jun proto-oncogene in apoptosis, involvement of SOCS1 in neural precursor cell accumulation in ischaemic regions, and the upregulation of C-EBPß in the hippocampus following I/R. Key to the study is understanding how Jun controls C-EBPß degradation via SOCS1, potentially offering new clinical treatment avenues for I/R. Techniques such as mRNA sequencing, KEGG enrichment analysis and protein-protein interaction (PPI) in mouse models have indicated involvement of Jun (AP-1) in I/R-induced cerebral damage. The study employs middle cerebral artery occlusion in different mouse models and oxygen-glucose deprivation/reoxygenation in cortical neurons to examine the impacts of Jun and SOCS1 manipulation on cerebral I/R injury and neuronal damage. The findings reveal that I/R reduces Jun expression in the brain, but its restoration lessens cerebral I/R injury and neuron death. Jun activates SOCS1 transcriptionally, leading to C-EBPß degradation, thereby diminishing cerebral I/R injury through the SOCS1/C-EBPß pathway. These insights provide a deeper understanding of post-I/R cerebral injury mechanisms and suggest new therapeutic targets for cerebral I/R injury. KEY POINTS: Jun and SOCS1 are poorly expressed, and C-EBPß is highly expressed in ischaemia/reperfusion mouse brain tissues. Jun transcriptionally activates SOCS1. SOCS1 promotes the ubiquitination-dependent C-EBPß protein degradation. Jun blunts oxygen-glucose deprivation/reoxygenation-induced neuron apoptosis and alleviates neuronal injury. This study provides a theoretical basis for the management of post-I/R brain injury.

Protective effects of fructose-1,6-bisphosphate postconditioning on myocardial ischaemia-reperfusion injury in patients undergoing valve replacement: a randomized, double-blind, placebo-controlled clinical trial.

OBJECTIVES: Pharmacological postconditioning can protect against myocardial ischaemia-reperfusion injury during cardiac surgery with extracorporeal circulation. The aim of this study was to observe the protective effects of fructose-1,6-bisphosphate (FDP) postconditioning on myocardial ischaemia-reperfusion injury in patients undergoing cardiac valve replacement with extracorporeal circulation. METHODS: Patients undergoing elective mitral valve replacement and/or aortic valve replacement were divided into normal saline postconditioning group (NS group) and FDP postconditioning group (FDP group). The primary outcome was the plasma concentration of creatine kinase-MB (CK-MB). The secondary outcomes were the plasma concentrations of lactate dehydrogenase, CK, high-sensitivity C-reactive protein, alpha-hydroxybutyrate dehydrogenase and cardiac troponin I, the spontaneous cardiac rhythm recovery profile, the extracorporeal circulation time and duration of surgery, intensive care unit and postoperative hospitalization. RESULTS: Forty patients were randomly assigned to receive intervention and included in the analysis. The serum concentrations of CK-MB, lactate dehydrogenase, CK, cardiac troponin I, alpha-hydroxybutyrate dehydrogenase and high-sensitivity C-reactive protein at T1∼4 were lower in the FDP group than in the NS group (P < 0.001). Compared with the NS group, the dosage of dopamine administered 1-90 min after cardiac resuscitation, the spontaneous cardiac rhythm recovery time and the incidence of ventricular fibrillation were lower in the FDP group (P < 0.001, P < 0.001 and P = 0.040, respectively). The values of ST- changes were increased more significantly in the NS group than in the FDP group (median [standard deviation] 1.3 [0.3] mm vs 0.7 [0.2] mm; P < 0.001). Compared with the NS group, the time of recovery of ST-segment deviations was shorter in the FDP group (50.3 [12.3] min vs 34.6 [6.9] min; P < 0.001). CONCLUSIONS: The FDP postconditioning could improve both myocardial ischaemia-reperfusion injury and the spontaneous cardiac rhythm recovery during cardiac valve surgery with extracorporeal circulation.

SENP1 reduces oxidative stress and apoptosis in renal ischaemia-reperfusion injury by deSUMOylation of HIF-1α.

Renal ischaemia-reperfusion injury (RIRI) is a primary cause of acute kidney damage, occurring frequently in situations like renal transplantation, yet the underlying mechanisms were not fully understood. Sentrin-specific protease 1 (SENP1) is an important member of the SENP family, which is widely involved in various diseases. However, the role of SENP1 in RIRI has been unclear. In our study, we discovered that SENP1 was involved in RIRI and reduced renal cell apoptosis and oxidative stress at elevated levels. Further mechanistic studies showed that hypoxia-inducible factor-1α (HIF-1α) was identified as a substrate of SENP1. Furthermore, SENP1 deSUMOylated HIF-1α, which reduced the degradation of HIF-1α, and exerted a renoprotective function. In addition, the protective function was lost after application of the HIF-1α specific inhibitor KC7F2. Briefly, our results fully demonstrated that SENP1 reduced the degradation of HIF-1α and attenuated oxidative stress and apoptosis in RIRI by regulating the deSUMOylation of HIF-1α, suggesting that SENP1 may serve as a potential therapeutic target for the treatment of RIRI.

Inhibition of inflammation and apoptosis through the cyclic GMP-AMP synthase-stimulator of interferon genes pathway by stress granules after ALKBH5 demethylase activation during diabetic myocardial ischaemia-reperfusion injury.

AIM: Post-transcriptional modifications and their specific mechanisms are the focus of research on the regulation of myocardial damage. Stress granules (SGs) can inhibit the inflammatory response by inhibiting the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway. This study investigated whether alkylation repair homologue protein 5 (ALKBH5) could affect myocardial inflammation and apoptosis during diabetic myocardial ischaemia-reperfusion injury (IRI) through the cGAS-STING pathway via SGs. METHODS: A diabetes ischaemia-reperfusion rat model and a high glucose hypoxia/reoxygenation cell model were established. Adeno-associated virus (AAV) and lentivirus (LV) were used to overexpress ALKBH5, while the SG agonist arsenite (Ars) and the SG inhibitor anisomycin were used as interventions. Then, the levels of apoptosis and related indicators in the cell and rat models were measured. RESULTS: In the in vivo experiment, compared with the normal sham group, the degree of myocardial tissue damage, creatine kinase-MB and cardiac troponin I in serum, and myocardial apoptosis, the infarcted area of myocardium, and the level of B-cell lymphoma 2 associated X protein, cGAS-STING pathway and inflammatory factors in the diabetes ischaemia-reperfusion group were significantly increased. However, the expression of SGs and the levels of ALKBH5, rat sarcoma-GTPase-activating protein-binding protein 1, T-cell intracellular antigen-1 and Bcl2 were significantly decreased. After AAV-ALKBH5 intervention, the degree of myocardial tissue damage, degree of myocardial apoptosis, and extent of myocardial infarction in myocardial tissue were significantly decreased. In the in vitro experiment, compared with those in the normal control group, the levels of lactate dehydrogenase, inflammation and apoptosis were significantly greater, and cell viability and the levels of ALKBH5 and SGs were decreased in the high glucose and hypoxia/reoxygenation groups. In the high glucose hypoxia/reoxygenation cell model, the degree of cell damage, inflammation, and apoptosis was greater than those in the high glucose and hypoxia/reoxygenation models, and the levels of ALKBH5 and SGs were further decreased. LV-ALKBH5 and Ars alleviated the degree of cell damage and inhibited inflammation and cell apoptosis. The inhibition of SGs could partly reverse the protective effect of LV-ALKBH5. The cGAS agonist G140 antagonized the inhibitory effects of the SG agonist Ars on cardiomyocyte apoptosis, inflammation and the cGAS-STING pathway. CONCLUSION: Both ALKBH5 and SGs inhibited myocardial inflammation and apoptosis during diabetic myocardial ischaemia-reperfusion. Mechanistically, ALKBH5 might inhibit the apoptosis of cardiomyocytes by promoting the expression of SGs through the cGAS-STING pathway.

Weighted gene co-expression network analysis and single-cell sequence analysis uncover immune landscape and reveal hub genes of necroptosis in macrophages in myocardial ischaemia-reperfusion injury.

Myocardial ischaemia-reperfusion injury (MIRI) caused by the treatment of acute myocardial infarction (AMI) is the primary cause of severe ventricular remodelling, heart failure (HF), and high mortality. In recent studies, research on the role of necroptosis in MIRI has focused on cardiomyocytes, but new biomarkers and immunocyte mechanisms of necroptosis are rarely studied. In the present study, weighted gene co-expression network analysis (WGCNA) algorithms were used to establish a weighted gene co-expression network, and Casp1, Hpse, Myd88, Ripk1, and Tpm3 were identified as biological markers of necroptosis using least absolute shrinkage, selection operator (LASSO) regression and support vector machine (SVM) feature selection algorithms. The role and discriminatory power of these five genes in MIRI had never been studied. Single-cell and cell-talk analyses showed that hub genes of necroptosis were focused on macrophages, which mediate the functions of monocytes, fibroblasts, haematopoietic stem cells, and cardiomyocytes, primarily through the TNF/TNFRSF1A interaction. The polarisation and functional activation of macrophages were affected by the MIF signalling network (MIF CD74/CXCR4 and MIF CD74/CD44) of other cells. The results of the immune infiltration assay showed that the five genes involved in necroptosis were significantly related to the infiltration and functional activity of M2 macrophages. TWS-119 is predicted to be a molecular drug that targets key MIRI genes. A mouse model was established to confirm the expression of five hub genes, and ventricular remodelling increased with time after ischaemia-reperfusion injury (IRI). Therefore, Casp1, Hpse, Myd88, Ripk1, and Tpm3 may be key genes regulating necroptosis and polarisation in macrophages, and causing ventricular remodelling.

A Novel Postconditioning Approach Attenuates Myocardial Ischaemia-Reperfusion Injury in Rats.

Background: Ischaemia-reperfusion injury (IRI) is the damage that occurs when blood flow is restored to a tissue or organ after a period of ischaemia. Postconditioning is a therapeutic strategy aimed at reducing the tissue damage caused by IRI. Postconditioning in rodents is a useful tool to investigate the potential mechanisms of postconditioning. Currently, there is no convenient approach for postconditioning rodents. Methods: Rats were subjected to a balloon postconditioning procedure. A balloon was used to control the flow in the vessel. This allowed for easy and precise manipulation of perfusion. Evans blue and triphenyltetrazolium chloride (TTC) double staining were used to determine the infarct size. Apoptosis in the myocardium was visualised and quantified by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). Western blotting was performed to assess the expression of key apoptotic proteins, i.e., B-cell lymphoma 2 (Bcl-2), Bcl-2 Associated X (Bax), and cleaved caspase-3. Results: The balloon control approach to postconditioning provided accurate control of coronary blood flow and simplified the postconditioning manipulation. Infarct size reduction was observed in IRI rats after post-conditioning. There was a decrease in cardiac apoptosis in IRI rats after conditioning, as detected by TUNEL staining. IRI rats showed increased Bcl-2 levels and decreased Bax and cleaved caspase-3 levels in the myocardium. Conclusions: Postconditioning was successfully applied in rats using this novel approach. Postconditioning with this approach reduced infarct size and apoptosis in the area at risk.

Ginsenoside Rg1 mitigates cerebral ischaemia/reperfusion injury in mice by inhibiting autophagy through activation of mTOR signalling.

Reperfusion injury, which is distinct from ischaemic injury, occurs when blood flow is restored in previously ischaemic brain tissue, further compromising neurons and other cells and worsening the injury. There is currently a lack of pharmaceutical agents and therapeutic interventions that specifically mitigate cerebral ischaemia/reperfusion (I/R) injury. Ginsenoside Rg1 (Rg1), a protopanaxatriol-type saponin isolated from Panax ginseng C. A. Meyer, has been found to protect against cerebral I/R injury, but its intricate protective mechanisms remain to be elucidated. Numerous studies have shown that autophagy plays a crucial role in protecting brain tissue during the I/R process and is emerging as a promising therapeutic strategy for effective treatment. In this study, we investigated whether Rg1 protected against I/R damage in vitro and in vivo by regulating autophagy. Both MCAO and OGD/R models were established. SK-N-AS and SH-SY5Y cells were subjected to OGD followed by reperfusion with Rg1 (4-32 µM). MCAO mice were injected with Rg1 (30 mg·kg-1·d-1. i.p.) for 3 days before and on the day of surgery. Rg1 treatment significantly mitigated ischaemia/reperfusion injury both in vitro and in vivo. Furthermore, we demonstrated that the induction of autophagy contributed to I/R injury, which was effectively inhibited by Rg1 in both in vitro and in vivo models of cerebral I/R injury. Rg1 inhibited autophagy through multiple steps, including impeding autophagy initiation, inducing lysosomal dysfunction and inhibiting cathepsin enzyme activities. We revealed that mTOR activation was pivotal in mediating the inhibitory effect of Rg1 on autophagy. Treatment with Torin-1, an autophagy inducer and mTOR-specific inhibitor, significantly reversed the impact of Rg1 on autophagy, decreasing its protective efficacy against I/R injury both in vitro and in vivo. In conclusion, our results suggest that Rg1 may serve as a promising drug candidate against cerebral I/R injury by inhibiting autophagy through activation of mTOR signalling.

Safety and efficacy of platelet-derived mitochondrial transplantation in ischaemic heart disease.

BACKGROUND: Acute ST-elevation myocardial infarction (STEMI) remains a globally significant health challenge in spite of improvement in management strategy. Being aware that mitochondrial dysfunction plays a crucial role in ischaemia-reperfusion injury (IRI) modulation, empirical evidence suggests functional mitochondrial transplantation strikes as a reliable therapeutic approach for patients with acute myocardial infarction. METHODS AND RESULTS: We conducted a prospective, triple-blinded, parallel-group, blocked randomised clinical trial to investigate the therapeutic effects and clinical outcomes of platelet-derived mitochondrial transplantation in 30 patients with acute STEMI, such that the 15 subjects in the control group were given standard of care treatment, whereas the subjects in the intervention group received autologous platelet-derived mitochondria through the intracoronary injection. We observed that within 40 days, the intervention group had a slightly greater improvement in the left ventricular ejection fraction (LVEF) compared to the control group and experienced a significant enhancement in the exercise capacity (p < 0.001). Moreover, major adverse cardiac events (MACE), arrhythmia, fever, and tachycardia were compared between the groups and lack of significant difference marks the safety of mitochondrial transplantation (p > 0.05). Furthermore, the two groups were not significantly distinct as regards the average length of stay for a hospitalisation (p > 0.05). CONCLUSION: We suggest platelet-derived mitochondrial transplantation appears as a beneficial and highly promising therapeutic option for patients of ischaemic heart disease (IHD); however, we are aware that further in-depth studies with larger sample sizes along with longer follow-up periods are necessary for validating the clinical implications of our findings.

Protective effect of ischaemic preconditioning on acute and chronic renal damage following ischaemia reperfusion injury: characterisation of fibrosis development after inflammation resolution.

OBJECTIVES: Acute Kidney Injury (AKI) and Chronic Kidney Disease (CKD) are increasingly recognised as one disease continuum, rather than distinct entities, and are associated with a huge burden to healthcare services. The leading cause of AKI worldwide is Ischaemia Reperfusion Injury (IRI), most commonly seen in clinical settings of sepsis-driven hypotension. Ischaemic Preconditioning (IPC) is a strategy aimed at reducing the deleterious effects of IRI. The objectives of this study were to demonstrate an efficacious in vivo model of Kidney IRI, and the protective influence of IPC in attenuating AKI and development of renal fibrosis. METHODS: A rat model of bilateral kidney IRI was used: Male Lewis rats (n=84) were assigned to IRI, sham or IPC. In IRI, renal pedicles were clamped for 45 minutes. IPC groups underwent pulsatile IPC prior to IRI. Kidneys were retrieved at 24 hours, 48 hours, 7 days, 14 days and 28 days, and assessed histologically. RESULTS: IRI led to marked AKI (24-48 h) and renal fibrosis development by 28 days. IPC attenuated this damage, with 66% less fibrosis. Interestingly, at 14-days, the histological appearance of both IRI and IPC kidneys was rather similar, potentially representing an important transitional point at which kidneys commit to either fibrosis or recovery. This may provide a suitable inflexion point for introduction of novel anti-fibrotic therapies. CONCLUSIONS: In conclusion, we have characterised a model of kidney injury from acute to chronic phases, allowing detailed mechanistic understanding and which can be manipulated by effective treatment strategies such as IPC.

The benefits of oral glucose-lowering agents: GLP-1 receptor agonists, DPP-4 and SGLT-2 inhibitors on myocardial ischaemia/reperfusion injury.

Myocardial infarction (MI) is a life-threatening cardiovascular disease that, on average, results in 8.5 million deaths worldwide each year. Timely revascularization of occluded vessels is a critical method of myocardial salvage. However, reperfusion paradoxically leads to the worsening of myocardial damage known as myocardial ischaemia/reperfusion injury (MI/RI). Therefore, reducing the size of myocardial infarction after reperfusion is critical and remains an important therapeutic goal. The susceptibility of the myocardium to MI/RI may be increased by diabetes. Currently, some traditional antidiabetic agents such as metformin reduce MI/RI by decreasing inflammation, inhibiting oxidative stress, and improving vascular endothelial function. This appears to be a new direction for the treatment of MI/RI. Recent cardiovascular outcome trials have shown that several oral antidiabetic agents, including glucagon-like peptide-1 receptor agonists (GLP-1RAs), dipeptidyl peptidase-4 inhibitors (DPP-4is), and sodium-glucose-linked transporter-2 inhibitors (SGLT-2is), not only have good antidiabetic effects but also have a protective effect on myocardial protection. This article aims to discuss the mechanisms and effects of oral antidiabetic agents, including GLP-1RAs, DPP-4is, and SGLT-2is, on MI/RI to facilitate their clinical application.

Dual-specificity phosphatase 26 protects against kidney injury caused by ischaemia-reperfusion through restraint of TAK1-JNK/p38-mediated apoptosis and inflammation of renal tubular epithelial cells.

Dual-specificity phosphatase 26 (DUSP26) acts as a pivotal player in the transduction of signalling cascades with its dephosphorylating activity. Currently, DUSP26 attracts extensive attention due to its particular function in several pathological conditions. However, whether DUSP26 plays a role in kidney ischaemia-reperfusion (IR) injury is unknown. Aims of the current work were to explore the relevance of DUSP26 in kidney IR damage. DUSP26 levels were found to be decreased in renal tubular epithelial cells following hypoxia-reoxygenation (HR) and kidney samples subjected to IR treatments. DUSP26-overexpressed renal tubular epithelial cells exhibited protection against HR-caused apoptosis and inflammation, while DUSP26-depleted renal tubular epithelial cells were more sensitive to HR damage. Upregulation of DUSP26 in rat kidneys by infecting adenovirus expressing DUSP26 markedly ameliorated kidney injury caused by IR, while also effectively reducing apoptosis and inflammation. The mechanistic studies showed that the activation of transforming growth factor-ß-activated kinase 1 (TAK1)-JNK/p38 MAPK, contributing to kidney injury under HR or IR conditions, was restrained by increasing DUSP26 expression. Pharmacological restraint of TAK1 markedly diminished DUSP26-depletion-exacebated effects on JNK/p38 activation and HR injury of renal tubular cells. The work reported a renal-protective function of DUSP26, which protects against IR-related kidney damage via the intervention effects on the TAK1-JNK/p38 axis. The findings laid a foundation for understanding the molecular pathogenesis of kidney IR injury and provide a prospective target for treating this condition.

Increasing expression of dual-specificity phosphatase 12 mitigates oxygen-glucose deprivation/reoxygenation-induced neuronal apoptosis and inflammation through inactivation of the ASK1-JNK/p38 MAPK pathway.

Dual-specificity phosphatase 12 (DUSP12) is abnormally expressed under various pathological conditions and plays a crucial role in the pathological progression of disorders. However, the role of DUSP12 in cerebral ischaemia/reperfusion injury has not yet been investigated. This study explored the possible link between DUSP12 and cerebral ischaemia/reperfusion injury using an oxygen-glucose deprivation/reoxygenation (OGD/R) model. Marked decreases in DUSP12 levels have been observed in cultured neurons exposed to OGD/R. DUSP12-overexpressed neurons were resistant to OGD/R-induced apoptosis and inflammation, whereas DUSP12-deficient neurons were vulnerable to OGD/R-evoked injuries. Further investigation revealed that DUSP12 overexpression or deficiency affects the phosphorylation of apoptosis signal-regulating kinase 1 (ASK1), c-Jun NH2-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) in neurons under OGD/R conditions. Moreover, blockade of ASK1 diminished the regulatory effect of DUSP12 deficiency on JNK and p38 MAPK activation. In addition, DUSP12-deficiency-elicited effects exacerbating neuronal OGD/R injury were reversed by ASK1 blockade. In summary, DUSP12 protects against neuronal OGD/R injury by reducing apoptosis and inflammation through inactivation of the ASK1-JNK/p38 MAPK pathway. These findings imply a neuroprotective function for DUSP12 in cerebral ischaemia/reperfusion injury.

miR-486-5p protects against rat ischemic kidney injury and prevents the transition to chronic kidney disease and vascular dysfunction.

AIM: Acute kidney injury (AKI) increases the risk for progressive chronic kidney disease (CKD). MicroRNA (miR)-486-5p protects against kidney ischemia-reperfusion (IR) injury in mice, although its long-term effects on the vasculature and development of CKD are unknown. We studied whether miR-486-5p would prevent the AKI to CKD transition in rat, and affect vascular function. METHODS: Adult male rats were subjected to bilateral kidney IR followed by i.v. injection of liposomal-packaged miR-486-5p (0.5 mg/kg). Kidney function and histologic injury were assessed after 24 h and 10 weeks. Kidney endothelial protein levels were measured by immunoblot and immunofluorescence, and mesenteric artery reactivity was determined by wire myography. RESULTS: In rats with IR, miR-486-5p blocked kidney endothelial cell increases in intercellular adhesion molecule-1 (ICAM-1), reduced neutrophil infiltration and histologic injury, and normalized plasma creatinine (P<0.001). However, miR-486-5p attenuated IR-induced kidney endothelial nitric oxide synthase (eNOS) expression (P<0.05). At 10 weeks, kidneys from rats with IR alone had decreased peritubular capillary density and increased interstitial collagen deposition (P<0.0001), and mesenteric arteries showed impaired endothelium-dependent vasorelaxation (P<0.001). These changes were inhibited by miR-486-5p. Delayed miR-486-5p administration (96 h, 3 weeks after IR) had no impact on kidney fibrosis, capillary density, or endothelial function. CONCLUSION: In rats, administration of miR-486-5p early after kidney IR prevents injury, and protects against CKD development and systemic endothelial dysfunction. These protective effects are associated with inhibition of endothelial ICAM-1 and occur despite reduction in eNOS. miR-486-5p holds promise for the prevention of ischemic AKI and its complications.