Acute Ischemia-reperfusion Injury Research Articles

Hypothermic oxygenated perfusion combined with TJ-M2010-5 alleviates hepatic ischemia-reperfusion injury in donation after circulatory death

Ischemia-reperfusion injury (IRI) is an inevitable pathological process during donation after circulatory death (DCD) liver transplantation, which contributes to serious damage to the graft. Oxidative stress, inflammation and apoptosis are all fatal causes of IRI of the liver. Hypothermic oxygenated perfusion (HOPE), as an emerging dynamic preservation technology, has a more significant effect on reducing DCD liver IRI than static cold storage (CS) mainly by regulating oxidative stress and inflammation. To further enhance the effect of HOPE and reveal its underlying mechanisms, investigators have recently combined HOPE with various methods. Excessive activation of the TLR/MyD88 signaling pathway can lead to severe immune inflammatory response. TJ-M2010-5 (TJ-5), a novel thiazaol-aminoramification MyD88 inhibitor, plays an essential role in the treatment of various diseases or pathological injuries in mice, such as hepatocellular carcinoma, acute liver injury and myocardial IRI. However, little is known about the role of TJ-5 in HOPE alleviating DCD liver IRI. Herein, we sought to investigate the role of HOPE combined with TJ-5 in reducing DCD liver IRI. We found that HOPE combined with TJ-5 significantly reduced oxidative stress, lessened inflammation, and decreased apoptosis during DCD liver IRI. Furthermore, HOPE combined with TJ-5 exerted their effects by inhibiting the TLR/MyD88 signaling pathway. Overall, these results demonstrated that HOPE combined with TJ-5 has a significant effect on alleviating DCD liver IRI. Therefore, the combined application of HOPE and TJ-5 may be an available and valid treatment option for DCD liver IRI.

Analysis of microRNA Expression after Glutamine Intervention in Acute Renal Ischemia-Reperfusion Injury.

Background Ischemia-reperfusion acute kidney injury (I/R AKI) is a severe kidney disease with high mortality and morbidity. This study aimed to explore the protective mechanism of glutamine (GLN) against I/R AKI. MethodsThe I/R AKI rat model was established, and HE staining of kidney tissue and serum creatinine (SCr) and blood urea nitrogen (BUN) detection were performed. The miRNAs were sequenced by high throughput in rat kidney tissue samples. Differentially expressed miRNAs (DEmiRs) between the I/R group and I/R + GLN group were screened, and enrichment analysis for target genes of DEmiRs was performed. Meanwhile, human HK-2 cells were cultured, and an I/R model was established to verify the expression of DEmiRs. Results Compared with the I/R group, the SCr and BUN levels at each time point were lower in the I/R + GLN group. Vacuolar degeneration of renal tubules in the I/R + GLN group was significantly reduced. In the 104 DEmiRs, we selected miR-132-5p, miR-205, and miR-615 as key miRNAs. KEGG analysis showed that the Notch signaling pathway, PI3K-Akt signaling pathway, and cGMP signaling pathway were mainly related to the GLN against I/R. qRT-PCR verified the downregulation of miR-205 in the I/R group, compared to the sham and I/R + GLN group. The I/R model was established with HK-2 cells, and the expression of miR-132-5p and miR-205 was decreased. Conclusion GLN reduced I/R-induced AKI. There were significant differences between miRNAs expression in I/R after GLN treatment. The process of GLN against I/R-induced AKI may be related to the Notch and PI3K-Akt signaling pathway.

Lupeol Alleviates Myocardial Ischemia-Reperfusion Injury in Rats by Regulating NF-[Formula: see text]B and Nrf2 Pathways.

Cardiovascular disease is a global health problem. Previous studies revealed that it involves acute myocardial infarction and ischemia-reperfusion (I/R) injury. The mechanism of myocardial I/R injury is complex. But recognizing its mechanisms will bring important clinical significance. Lupeol is widely found in Chinese medicinal herbs and has been shown to have a variety of bio-activities. However, the pharmacological action of lupeol in the progress of myocardial ischemia-reperfusion injury (MIRI) is unclear. This study used a rat myocardial I/R model and the morphological changes in myocardium were determined by 2,3,5-triphenyltetrazolium chloride (TTC) staining. The expression levels of IL-10, IL-1[Formula: see text], TNF-[Formula: see text], and IL-6 were assessed by quantitative real-time PCR (qRT-PCR) and ELISA. The expression levels of MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase (LDH) level and inflammatory cytokines were quantified using ELISA. The cellular apoptotic rate was determined by TUNEL staining. The findings showed that lupeol significantly decreased myocardial infarction after I/R and ameliorated I/R-induced myocardial inflammation, apoptosis, and oxidative stress. Furthermore, our results suggested that lupeol protected against MIRI-induced myocardial infarction through modulation of NF-[Formula: see text]B and Nrf2 signaling pathways. In summary, this study first clarified the cardioprotective effects of lupeol against I/R-induced myocardial infarction in rats, which could be due to its anti-oxidant, anti-inflammatory, and anti-apoptotic activities. Our study also highlighted a mechanism of NF-[Formula: see text]B and Nrf2 signaling, through which lupeol could be a promising agent in protecting against I/R-induced myocardial infarction.

Impact of Acute Ischemia-Reperfusion Injury on Left Ventricular Pressure-Volume Relations in Dogs

Objective: Ischemic conditioning (IC) limits myocyte necrosis after acute myocardial ischemia-reperfusion; however, controversy persists regarding its potential to attenuate LV contractile dysfunction. Pressure-volume (P-V) loop analysis, via the load-insensitive conductance catheter method, was used to evaluate LV contractility, diastolic function, and ventriculo-arterial coupling. The goal of this study was to evaluate the ability of IC to improve post-ischemic recovery of LV contractile function. Methods: Twelve anesthetized dogs were randomly distributed to either the IC or the non-IC group; all dogs were subject to 60-min acute coronary occlusion followed by 180-min reperfusion. IC consisted of 4 repeated cycles of 5-min occlusion and 5-min reperfusion of the left main coronary artery. LV P-V relations were constructed under steady-state conditions (by inferior vena cava occlusion) at the beginning and end of the experiments; P-V loops were acquired at different time points before and during ischemia-reperfusion. Results: During ischemia and reperfusion, dP/dtmax decreased significantly compared to baseline in both groups; dP/dtmin, an indicator of the rate of LV relaxation rate was not affected for either group. Significant changes in several parameters of LV function including LVEF, SW, tPFR, ESV, and EDV caused by ischemia were also identified; none of these negative effects were resorbed, even in part, during reperfusion. Conclusions: Diminished LV contractile efficiency during systole and diastole produced by ischemia-reperfusion did not improve with IC pre-treatment despite significant endogenous protection against tissue necrosis.

Human Lysyl Oxidase Over-Expression Enhances Baseline Cardiac Oxidative Stress but Does Not Aggravate ROS Generation or Infarct Size Following Myocardial Ischemia-Reperfusion

Lysyl oxidase (LOX) is an enzyme critically involved in collagen maturation, whose activity releases H2O2 as a by-product. Previous studies demonstrated that LOX over-expression enhances reactive oxygen species (ROS) production and exacerbates cardiac remodeling induced by pressure overload. However, whether LOX influences acute myocardial infarction and post-infarct left ventricular remodeling and the contribution of LOX to myocardial oxidative stress following ischemia-reperfusion have not been analyzed. Isolated hearts from transgenic mice over-expressing human LOX in the heart (TgLOX) and wild-type (WT) littermates were subjected to global ischemia and reperfusion. Although under basal conditions LOX transgenesis is associated with higher cardiac superoxide levels than WT mice, no differences in ROS production were detected in ischemic hearts and a comparable acute ischemia-reperfusion injury was observed (infarct size: 56.24 ± 9.44 vs. 48.63 ± 2.99% of cardiac weight in WT and TgLOX, respectively). Further, similar changes in cardiac dimensions and function were observed in TgLOX and WT mice 28 days after myocardial infarction induced by transient left anterior descending (LAD) coronary artery occlusion, and no differences in scar area were detected (20.29 ± 3.10 vs. 21.83 ± 2.83% of left ventricle). Our data evidence that, although LOX transgenesis induces baseline myocardial oxidative stress, neither ROS production, infarct size, nor post-infarction cardiac remodeling were exacerbated following myocardial ischemia-reperfusion.

Total Flavonoids of Chuju Decrease Oxidative Stress and Cell Apoptosis in Ischemic Stroke Rats: Network and Experimental Analyses.

Background: Pharmacological research results showed that total flavonoids of Chuju (TFCJ) could be used to treat acute myocardial ischemia and myocardial ischemia-reperfusion injury. In this study, we explored the protective effect of TFCJ on ischemic stroke (IS) in the IS rat model. We hypothesized that TFCJ might exert its neuroprotective effects by suppressing apoptosis and oxidative stress that are closely related to PI3K/Akt/mTOR signaling pathway.Method: TFCJ (10, 20, and 40 mg/kg) was administered for 7 days. Rats (260 ± 20 g) were subjected to middle cerebral artery occlusion (MCAO) for 2 h and reperfusion for 24 h. The neuroprotective effect of TFCJ was substantiated in terms of neurological deficits, oxidative stress (superoxide dismutase, glutathione peroxidase, catalase, and malondialdehyde), pathomorphological changes (HE staining and TUNEL staining), and neurobehavioral functions in the rats. Then, we employed network pharmacology to reveal the potential mechanism of TFCJ against IS. Western blot was used to determine the levels of PI3K/AKT/mTOR pathway proteins. The expression of BCL-2, BAX, and cleaved-Caspase-3 was also measured by Western blots and RT-PCR.Results: The histopathological assessment showed that TFCJ reduced MCAO-induced brain damage. Besides, TFCJ exerted a protective role in MCAO rats by alleviating cell apoptosis and oxidative stress. Network pharmacology showed that TFCJ might be used against IS through the PI3K/AKT signaling pathway. TFCJ reduced cell apoptosis and oxidative stress by increasing the level of p-AKT and p-mTOR in MCAO rats, while the effect of TFCJ was significantly reversed when applying LY294002 (PI3k inhibitor).Conclusion: These results indicated that TFCJ might decrease oxidative stress and apoptosis that are closely related to PI3K/Akt/mTOR pathway in IS. TFCJ is a promising authentic traditional Chinese medicine for the management of IS.

The effect of mesenchymal stromal cells of various origins on mortality and neurologic deficit in acute ischemia-reperfusion in rats

Stroke is a global epidemic issue and the second leading cause of death in the world and in Ukraine. According to official statistics, every year 100-110 thousand Ukrainians suffer acute cerebrovascular disorders. One third of such patients are of working age, up to 50 % will have a disability, and only one in ten will fully return to full life. So far, promising experimental data on the treatment of neurological dysfunction using mesenchymal stromal cells (MSCs) have been obtained. The aim of study is to compare the effect of MSCs of different origins on mortality and neurologic deficit in rats with acute cerebral ischemia-reperfusion injury (CIRI). Materials and methods. Transient bilateral 20-minute occlusion of internal carotid arteries was modeled in male Wistar rats aged 4 months and animals were injected intravenously with MSCs derived from human umbilical cord Wharton's-jelly (hWJ-MSC), human and rat adipose tissue. Other groups of experimental animals were injected intravenously with rat fetal fibroblasts and cell lysate from hWJ-MSC. The last group of rats received Citicoline at a dose of 250 mg/kg as a reference drug. Control animals were injected intravenously with normal saline. The cerebroprotective effect of therapy was assessed by mortality and neurologic deficit in rats on the McGraw's stroke index score. Results. After 12 hours of observation in the crucial period in the development of experimental acute cerebrovascular disorders with the administration of hWJ-MSC, mortality was only 10 % against 45 % of animals in the control group. The use of rat fetal fibroblasts reduced the mortality of animals compare to the control group by an average of 25 %. CIRI in rats caused severe neurologic deficits: paralysis, paresis, ptosis, circling behavior. On the 7th day of observation in the control group of animals, the mean score on the McGrow's stroke index indicated severe neurological disorders. On the 14th day of observation in this group of animals there was no complete recovery of lost central nervous system functions. Compared with the control group of animals, all the treatment agents for acute CIRI (MSCs of various origins, MSC's lysate and Citicoline) contributed to a significant regression of neurologic deficit. Conclusions. Thus, transplantation of human Wharton's jelly-derived MSCs and rat fetal fibroblasts reduced mortality and alleviated neurological symptoms in rats with experimental ischemic stroke. hWJ-MSC, rat fetal fibroblasts, and rat adipose-derived MSCs reduced the incidence of neurological disorders better than Citicoline, which was accompanied by a regression of neurologic deficit dynamics on the 14th day of follow-up. The ability of stem cells of different origins to reduce neurologic deficit indicates the feasibility of their use in experimental acute cerebral ischemia.

Can Erythropoietin Reduce Hypoxemic Neurological Damages in Neonates With Congenital Heart Defects?

Congenital heart defects (CHD), the most common cause of birth defects with increasing birth prevalence, affect nearly 1% of live births worldwide. Cyanotic CHD are characterized by hypoxemia, with subsequent reduced oxygen delivery to the brain, especially critical during brain development, beginning in the fetus and continuing through the neonatal period. Therefore, neonates with CHD carry a high risk for neurological comorbidities, even more frequently when there are associated underlying genetic disorders. We review the currently available knowledge on potential prevention strategies to reduce brain damage induced by hypoxemia during fetal development and immediately after birth, and the role of erythropoietin (EPO) as a potential adjunctive treatment. Maternal hyper-oxygenation had been studied as a potential therapeutic to improve fetal oxygenation. Despite demonstrating some effectiveness, maternal hyper-oxygenation has proven to be impractical for extensive clinical application, thus prompting the investigation of specific pathways for pharmacological intervention. Among those, the role of antioxidant pathways and Hypoxia Inducible Factors (HIF) have been studied for their involvement in the protective response to hypoxic injury. One of the proteins induced by HIF, EPO, has properties of being anti-apoptotic, antioxidant, and protective for neurons, astrocytes, and oligodendrocytes. In human trials, EPO administration in neonates with hypoxic ischemic encephalopathy (HIE) significantly reduced the neurological hypoxemic damages in several reported studies. Currently, it is unknown if the mechanisms of pathophysiology of cyanotic CHD are like HIE. Neonates with cyanotic CHD are exposed to both chronic hypoxemia and episodes of acute ischemia-reperfusion injury when undergo cardiopulmonary bypass surgery requiring aortic cross-clamp and general anesthesia. Our review supports future trials to evaluate the potential efficiency of EPO in reducing the hypoxemic neurologic damages in neonates with CHD. Furthermore, it suggests the need to identify early biomarkers of hypoxia-induced neurological damage, which must be sensitive to the neuroprotective effects of EPO.

Influence of Intrinsic Aerobic Exercise Capacity and Sex on Cardiac Injury Following Acute Myocardial Ischemia and Reperfusion.

Purpose: Previous reports have suggested that active exercise aside, intrinsic aerobic running capacity (Low = LCR, high = HCR) in otherwise sedentary animals may influence several cardiovascular health-related indicators. Relative to the HCR phenotype, the LCR phenotype is characterized by decreased endothelial reactivity, increased susceptibility to reperfusion-induced arrhythmias following short, non-infarction ischemia, and increased diet-induced insulin resistance. More broadly, the LCR phenotype has come to be characterized as a “disease prone” model, with the HCRs as “disease resistant.” Whether these effects extend to injury outcomes in an overt infarction or whether the effects are gender specific is not known. This study was designed to determine whether HCR/LCR phenotypic differences would be evident in injury responses to acute myocardial ischemia-reperfusion injury (AIR), measured as infarct size and to determine whether sex differences in infarction size were preserved with phenotypic selection.Methods: Regional myocardial AIR was induced in vivo by either 15 or 30 min ligation of the left anterior descending coronary artery, followed by 2 h of reperfusion. Global ischemia was induced in isolated hearts ex vivo using a Langendorff perfusion system and cessation of perfusion for either 15 or 30 min followed by 2 h of reperfusion. Infarct size was determined using 2, 3, 5–triphenyltetrazolium chloride (TTC) staining, and normalized to area at risk in the regional model, or whole heart in the global model. Portions of the tissue were paraffin embedded for H&E staining and histology analysis.Results: Phenotype dependent differences in infarct size were seen with 15 min occlusion/2 h reperfusion (LCR > HCR, p < 0.05) in both regional and global models. In both models, longer occlusion times (30 min/2 h) produced significantly larger infarctions in both phenotypes, but phenotypic differences were no longer present (LCR vs. HCR, p = n.s.). Sex differences in infarct size were present in each phenotype (LCR male > LCR female, p < 0.05; HCR male > HCR female, p < 0.05 regardless of length of occlusion, or ischemia model.Conclusions: There is cardioprotection afforded by high intrinsic aerobic capacity, but it is not infinite/continuous, and may be overcome with sufficient injury burden. Phenotypic selection based on endurance running capacity preserved sex differences in response to both short and longer term coronary occlusive challenges. Outcomes could not be associated with differences in system characteristics such as circulating inflammatory mediators or autonomic nervous system influences, as similar phenotypic injury patterns were seen in vivo, and in isolated crystalloid perfused heart ex vivo.

Hyperbaric oxygen therapy does not alleviate tourniquet-induced acute ischemia-reperfusion injury in mouse skeletal muscles

During tourniquet application, blood flow is restricted to a limb to stop excessive limb hemorrhage in a trauma setting and to create a bloodless operating field in the surgical setting. During tourniquet-related ischemia, aerobic respiration stops, and ATP is depleted, and during subsequent reperfusion, there is an increase in reactive oxygen species (ROS) production and other endogenous substances, which leads to acute ischemia-reperfusion (IR) injuries, including tissue necrosis and skeletal muscle contractile dysfunction. Hyperbaric oxygen (HBO) therapy can increase the arterial oxygen tension in the tissues of patients with general hypoxia/anoxia, including carbon monoxide poisoning, circulatory arrest, and cerebral and myocardial ischemia. Here, we studied the protective effects of HBO pretreatment with 100% oxygen at 2.5 ATA against tourniquet/IR injury in mice. After one hour of HBO therapy with 100% oxygen at 2.5 ATA was administered to C57/BL6 mice, a rubber band was placed at the hip joint of the unilateral hindlimb to induce 3 h of ischemia and then released for 48 h of reperfusion. We analyzed gastrocnemius muscle morphology and contractile function and measured the levels of ATP and ROS accumulation in the muscles. HBO pretreatment did not improve tourniquet/IR-injured gastrocnemius muscle morphology and muscle contraction. Tourniquet/IR mice with HBO pretreatment showed no increase in ATP levels in IR tissues, but they did have a decreased amount of ROS accumulation in the muscles, compared to IR mice with no HBO pretreatment. These data suggest that one hour of HBO pretreatment with 100% oxygen at 2.5 ATA increases the antioxidant response to lower ROS accumulation but does not increase ATP levels in IR muscles and improve tourniquet/IR-injured muscle morphology and contractile function.

A Randomized, double-blind, dose ranging clinical trial of intravenous FDY-5301 in acute STEMI patients undergoing primary PCI

BackgroundIschemia-reperfusion injury remains a major clinical problem in patients with ST-elevation myocardial infarction (STEMI), leading to myocardial damage despite early reperfusion by primary percutaneous coronary intervention (PPCI). There are no effective therapies to limit ischemia-reperfusion injury, which is caused by multiple pathways activated by rapid tissue reoxygenation and the generation of reactive oxygen species (ROS).FDY-5301 contains sodium iodide, a ubiquitous inorganic halide and elemental reducing agent that can act as a catalytic anti-peroxidant. We tested the feasibility, safety and potential utility of FDY-5301 as a treatment to limit ischemia-reperfusion injury, in patients with first-time STEMI undergoing emergency PPCI. MethodsSTEMI patients (n = 120, median 62 years) presenting within 12 h of chest pain onset were randomized at 20 PPCI centers, in a double blind Phase 2 clinical trial, to receive FDY-5301 (0.5, 1.0 or 2.0 mg/kg) or placebo prior to reperfusion, to evaluate the feasibility endpoints. Participants underwent continuous ECG monitoring for 14 days after PPCI to address pre-specified cardiac arrhythmia safety end points and cardiac magnetic resonance imaging (MRI) at 72 h and at 3 months to assess exploratory efficacy end points. ResultsIntravenous FDY-5301 was delivered before re-opening of the infarct-related artery in 97% participants and increased plasma iodide levels ~1000-fold within 2 min. There was no significant increase in the primary safety end point of incidence of cardiac arrhythmias of concern. MRI at 3 months revealed median final infarct sizes in placebo vs. 2.0 mg/kg FDY-5301-treated patients of 14.9% vs. 8.5%, and LV ejection fractions of 53.9% vs. 63.2%, respectively, although the study was not powered to detect statistical significance. In patients receiving FDY-5301, there was a significant reduction in the levels of MPO, MMP2 and NTproBNP after PPCI, but no reduction with placebo. ConclusionsIntravenous FDY-5301, delivered immediately prior to PPCI in acute STEMI, is feasible, safe, and shows potential efficacy. A larger trial is justified to test the effects of FDY-5301 on acute ischemia-reperfusion injury and clinical outcomes.Clinical Trial Registration: CT.govNCT03470441; EudraCT 2017-000047-41

Current Strategies to Minimize Ischemia-Reperfusion Injury in Liver Transplantation: A Systematic Review.

Hepatic Ischemia Reperfusion Injury (IRI) is a serious threat that characterizes the liver but also other transplantable organs. The worst effect of long-term IRI on an impaired graft could lead to irreversible damage and organ failure. Several events characterize the cascade that ultimately leads to organ failure. Among all, multiple strategies have been attempted to identify early phenomena of IRI with divergent results, and biomarkers might represent a novel approach to early detect ischemic damage. A literature review of the current state-of-the-art on IRI was conducted in the present manuscript. Information was collected from worldwide clinical trials conducted in highly specialized institutions. Experiments conducted on IRI animal models and clinical studies were screened. The final outcomes were analyzed and reported in the present review. Matrix Metalloproteinases (MMPs) represent an interesting example of the early detector of neutrophil invasion after acute and chronic hepatic IRI. Neutrophil Gelatinase-associated Lipocalin (NGAL) is another biomarker which seems more predictable of the IRI gravity phase. Mitochondrial flavin mononucleotide (FMN) was recently discovered and might become a reliable biomarker of hepatic IRI during Hypothermic Oxygenation Machine Perfusion (HOPE). The available strategies to avoid IRI, despite constantly improving, are still lacking a gold standard method. Further studies are still needed to explore new options in the IRI diagnosis and treatment, and to this purpose, regenerative medicine and tissue engineering surely can play a pivotal role in the transplantation field.

Hydrogen-Rich Water Improves Cognitive Ability and Induces Antioxidative, Antiapoptotic, and Anti-Inflammatory Effects in an Acute Ischemia-Reperfusion Injury Mouse Model.

Background Cerebral ischemia and its reperfusion injury facilitate serious neurodegenerative diseases such as dementia due to cell death; however, there is currently no treatment for it. Reactive oxygen species is one of the many factors that induce and worsen the development of such diseases, and it can be targeted by hydrogen treatment. This study examined the effect of molecular hydrogen in cerebral ischemia-reperfusion injury, which is emerging as a novel therapeutic agent for various diseases. Methods Ischemia-reperfusion injury was generated through bilateral common carotid artery occlusion in C57BL/6 mice. The test group received hydrogen-rich water orally during the test period. To confirm model establishment and the effect of hydrogen treatment, behavioural tests, biochemical assays, immunofluorescence microscopy, and cytokine assays were conducted. Results Open field and novel object recognition tests revealed that the hydrogen-treated group had improved cognitive function and anxiety levels compared to the nontreated group, while hematoxylin and eosin stain showed abundant pyknotic cells in a model mouse brain, and this was attenuated in the hydrogen-treated mouse brain. Total antioxidant capacity and thiobarbituric acid reactive substance assays revealed that hydrogen treatment induced antioxidative effects in the mouse brain. Immunofluorescence microscopy revealed attenuated apoptosis in the striatum, cerebral cortex, and hippocampus of hydrogen-treated mice. Western blotting showed that hydrogen treatment reduced Bax and TNFα levels. Finally, cytokine assays showed that IL-2 and IL-10 levels significantly differed between the hydrogen-treated and nontreated groups. Conclusion Hydrogen treatment could potentially be a future therapeutic strategy for ischemia and its derived neurodegenerative diseases by improving cognitive abilities and inducing antioxidative and antiapoptotic effects. Hydrogen treatment also decreased Bax and TNFα levels and induced an anti-inflammatory response via regulation of IL-2 and IL-10. These results will serve as a milestone for future studies intended to reveal the mechanism of action of molecular hydrogen in neurodegenerative diseases.

Remote liver injury following acute renal ischaemia–reperfusion: involvement of circulating exosomal miR‐687 and regulation by thymoquinone

What is the central question of this study? What is the role of circulating exosomal miR-687 in remote hepatic injury following renal ischaemia-reperfusion injury (IRI) and does thymoquinone have a modulatory impact? What is the main finding and its importance? Exosomal miR-687 was expressed in renal IRI, entered the circulation and was deposited in the liver. Liver exosomal miR-687 was correlated with liver inflammation and apoptosis. Thymoquinone aborted the renal production of exosomal miR-687 and its further circulation to the liver. The pathophysiology of remote hepatic injury following acute renal ischaemia-reperfusion injury (IRI) is of particular clinical interest. Secreted small non-coding microRNA (miRs) are thought to exist in exosome-encapsulated form. Thymoquinone (TQ) is the main bioactive ingredient of Nigella sativa and has several renoprotective actions. We expected exosomal miR-687 to be relevant as it could act as a humoral mediator, with possible modulation by TQ. Thirtyadult male Wister albino rats were assigned to three groups (n=10); (1) sham-operated, (2) renal ischaemia-reperfusion injury (IRI), and (3) renal IRI pre-treated with TQ 10mg/kg/day i.v. (TQ-IRI) for 10days in addition to a dose administered at reperfusion onset. Following 24h of reperfusion, the IRI group showed renal tissue hypoxia-inducible factor upregulation (P<0.001). Electron microscopy images of exosomes and analysis of miR-687 revealed elevated levels, which appeared in the circulation. Large amounts of exosomal miR-687 were transmitted to the liver tissue. In the IRI group, liver transaminases (alanine aminotransferase, aspartate aminotransferase) were markedly (P<0.001) elevated. The hepatic tissue inflammatory markers (vascular cell adhesion molecule-1, myeloperoxidase, monocyte chemotactic protein-1 and nuclear factor-κB) were upregulated (P<0.001) accompanied with elevated caspase-3. TQ suppressed (P<0.001) the renal expression and release of exosomal miR-687 into the circulation and its further deposition in the liver tissue; consequently, TQ diminished (P<0.001) liver tissue inflammation and cellular apoptosis. The results were confirmed by histological tissue assessment. In conclusion, exosomal miR-687 liberated from injured renal tissues into the circulation may be an important factor in inducing remote hepatic injury. Exosomal miR-687 inhibition by TQ protected both renal and hepatic tissues from injury.

Extracellular vesicles derived from melatonin-preconditioned mesenchymal stem cells containing USP29 repair traumatic spinal cord injury by stabilizing NRF2.

Spinal cord injury (SCI) is a devastating trauma that leads to irreversible motor and sensory dysfunction and is, so far, without effective treatment. Recently, however, nano-sized extracellular vesicles derived from preconditioned mesenchymal stem cells (MSCs) have shown great promise in treating various diseases, including SCI. In this study, we investigated whether extracellular vesicles (MEVs) derived from MSCs pretreated with melatonin (MT), which is well recognized to be useful in treating diseases, including Alzheimer's disease, non-small cell lung cancer, acute ischemia-reperfusion liver injury, chronic kidney disease, and SCI, are better able to promote functional recovery in mice after SCI than extracellular vesicles derived from MSCs without preconditioning (EVs). MEVs were found to facilitate motor behavioral recovery more than EVs and to increase microglia/macrophages polarization from M1-like to M2-like in mice. Experiments in BV2 microglia and RAW264.7 macrophages confirmed that MEVs facilitate M2-like polarization and also showed that they reduce the production of reactive oxygen species (ROS) and regulate mitochondrial function. Proteomics analysis revealed that ubiquitin-specific protease 29 (USP29) was markedly increased in MEVs, and knockdown of USP29 in MEVs (shUSP29-MEVs) abolished MEVs-mediated benefits in vitro and in vivo. We then showed that USP29 interacts with, deubiquitinates and therefore stabilizes nuclear factor-like 2 (NRF2), thereby regulating microglia/macrophages polarization. In NRF2 knockout mice, MEVs failed to promote functional recovery and M2-like microglia/macrophages polarization. We also showed that MT reduced global N6-methyladenosine (m6 A) modification and levels of the m6 A "writer" methyltransferase-like 3 (METTL3). The stability of USP29 mRNA in MSCs was enhanced by treatment with MT, but inhibited by overexpression of METTL3. This study describes a very promising extracellular vesicle-based approach for treating SCI.

Lack of gamma delta T cells ameliorates inflammatory response after acute intestinal ischemia reperfusion in mice

T-cells have been demonstrated to modulate ischemia–reperfusion injury (IRI) in the kidney, lung, liver, and intestine. Whereas most T-cell subpopulations contribute primarily to the antigen-specific effector and memory phases of immunity, γδ-T-cells combine adaptive features with rapid, innate-like responses that can place them in the initiation phase of immune reactions. Therefore, we aimed to clarify the role of γδ-T-cells in intestinal IRI. Adult wild-type (WT) and γδ-T-cell-deficient mice were subjected to acute intestinal IRI. Gene expression of pro-inflammatory cytokines and influx of leukocyte subpopulations in the gut were assessed by qPCR and flow cytometry. Serum transaminases were measured as an indicator of distant organ IRI. Intestinal IRI led to increased influx of neutrophils, pro-inflammatory cytokine expression and LDH/ALT/AST elevation. Selective deficiency of γδ-T-cells significantly decreased pro-inflammatory cytokine levels and neutrophil infiltration in the gut following IRI compared to controls. Furthermore, γδ-T-cell deficiency resulted in decreased LDH and transaminases levels in sera, indicating amelioration of distant organ injury. Increasing evidence demonstrates a key role of T-cell subpopulations in IRI. We demonstrate that γδ-T-cell deficiency ameliorated pro-inflammatory cytokine production, neutrophil recruitment and distant organ injury. Thus, γδ-T-cells may be considered as mediators contributing to the inflammatory response in the acute phase of intestinal IRI.

Beneficial Electrophysiological Effects of Rotigaptide Are Unable to Suppress Therapeutic Hypothermia-Provoked Ventricular Fibrillation in Failing Rabbit Hearts With Acute Ischemia-Reperfusion Injury.

Aims: Whether therapeutic hypothermia (TH) is proarrhythmic in preexisting failing hearts with acute ischemia–reperfusion (IR) injury is unknown. Additionally, the effectiveness of rotigaptide on improving conduction slowing in hearts with IR injury is ambiguous. We investigated the electrophysiological effects of TH and rotigaptide in failing rabbit hearts with acute IR injury and determined the underlying molecular mechanisms.Methods and Results: Heart failure was induced by right ventricular pacing (320 beats/min, 4 weeks). Rabbits with pacing-induced heart failure were randomly divided into TH (n = 14) and non-TH (n = 7) groups. The IR rabbit model was created by ligating the coronary artery for 60 min, followed by reperfusion for 15 min in vivo. Then, the hearts were excised quickly and Langendorff-perfused for simultaneous voltage and intracellular Ca2+ (Cai) optical mapping. Electrophysiological studies were conducted, and vulnerability to ventricular fibrillation (VF) was evaluated using pacing protocols. TH (33°C) was instituted after baseline studies, and electrophysiological studies were repeated. Rotigaptide (300 nM) was infused for 20 min, and electrophysiological studies were repeated under TH. Cardiac tissues were sampled for Western blotting. TH increased the dispersion and beat-to-beat variability of action potential duration (APD), aggravated conduction slowing, and prolonged Cai decay to facilitate spatially discordant alternans (SDA) and VF induction. Rotigaptide reduced the dispersion and beat-to-beat variability of APD and improved slowed conduction to defer the onset of arrhythmogenic SDA by dynamic pacing and elevate the pacing threshold of VF during TH. However, the effect of rotigaptide on TH-enhanced VF inducibility was statistically insignificant. TH attenuated IR-induced dysregulation of protein expression, but its functional role remained uncertain.Conclusion: Therapeutic hypothermia is proarrhythmic in failing hearts with acute IR injury. Rotigaptide improves TH-induced APD dispersion and beat-to-beat variability and conduction disturbance to defer the onset of arrhythmogenic SDA and elevate the VF threshold by dynamic pacing, but these beneficial electrophysiological effects are unable to suppress TH-enhanced VF inducibility significantly.

Caspase-3-dependent peritubular capillary dysfunction is pivotal for the transition from acute to chronic kidney disease after acute ischemia-reperfusion injury.

Ischemia-reperfusion injury (IRI) is a major risk factor for chronic renal failure. Caspase-3, an effector responsible for apoptosis execution, is activated within the peritubular capillary (PTC) in the early stage of IRI-induced acute kidney injury (AKI). Recently, we showed that caspase-3-dependent microvascular rarefaction plays a key role in fibrosis development after mild renal IRI. Here, we further characterized the role of caspase-3 in microvascular dysfunction and progressive renal failure in both mild and severe AKI, by performing unilateral renal artery clamping for 30/60 min with contralateral nephrectomy in wild-type (C57BL/6) or caspase-3-/- mice. In both forms of AKI, caspase-3-/- mice showed better long-term outcomes despite worse initial tubular injury. After 3 wk, they showed reduced PTC injury, decreased PTC collagen deposition and α-smooth muscle actin expression, and lower tubular injury scores compared with wild-type animals. Caspase-3-/- mice with severe IRI also showed better preservation of long-term renal function. Intravital imaging and microcomputed tomography revealed preserved PTC permeability and better terminal capillary density in caspase-3-/- mice. Collectively, these results demonstrate the pivotal importance of caspase-3 in regulating long-term renal function after IRI and establish the predominant role of PTC dysfunction as a major contributor to progressive renal dysfunction.NEW & NOTEWORTHY Our findings demonstrate the pivotal importance of caspase-3 in regulating renal microvascular dysfunction, fibrogenesis, and long-term renal impairment after acute kidney injury induced by ischemia-reperfusion injury. Furthermore, this study establishes the predominant role of peritubular capillary integrity as a major contributor to progressive renal dysfunction after ischemia-reperfusion injury.

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

Ischemia-reperfusion injury (IRI) is one of the major risk factors implicated in morbidity and mortality associated with cardiovascular disease. During cardiac ischemia, the buildup of acidic metabolites results in decreased intracellular and extracellular pH, which can reach as low as 6.0 to 6.5. The resulting tissue acidosis exacerbates ischemic injury and significantly affects cardiac function. We used genetic and pharmacologic methods to investigate the role of acid-sensing ion channel 1a (ASIC1a) in cardiac IRI at the cellular and whole-organ level. Human induced pluripotent stem cell-derived cardiomyocytes as well as ex vivo and in vivo models of IRI were used to test the efficacy of ASIC1a inhibitors as pre- and postconditioning therapeutic agents. Analysis of human complex trait genetics indicates that variants in the ASIC1 genetic locus are significantly associated with cardiac and cerebrovascular ischemic injuries. Using human induced pluripotent stem cell-derived cardiomyocytes in vitro and murine ex vivo heart models, we demonstrate that genetic ablation of ASIC1a improves cardiomyocyte viability after acute IRI. Therapeutic blockade of ASIC1a using specific and potent pharmacologic inhibitors recapitulates this cardioprotective effect. We used an in vivo model of myocardial infarction and 2 models of ex vivo donor heart procurement and storage as clinical models to show that ASIC1a inhibition improves post-IRI cardiac viability. Use of ASIC1a inhibitors as preconditioning or postconditioning agents provided equivalent cardioprotection to benchmark drugs, including the sodium-hydrogen exchange inhibitor zoniporide. At the cellular and whole organ level, we show that acute exposure to ASIC1a inhibitors has no effect on cardiac ion channels regulating baseline electromechanical coupling and physiologic performance. Our data provide compelling evidence for a novel pharmacologic strategy involving ASIC1a blockade as a cardioprotective therapy to improve the viability of hearts subjected to IRI.

Eupatilin pretreatment ameliorates hepatic ischemia-reperfusion injury in mice

Eupatilin, a pharmacologically active flavone derived from Artemisia species, is known to have antioxidant and anti-inflammatory activities. Ischemia-reperfusion injury (IRI) is a major critical event that commonly occurs after liver transplantation and resection. Furthermore, inflammatory responses to IRI exacerbate the resultant hepatic injury. In this study, we investigated whether eupatilin protects against IR-induced acute liver injury in mice. Partial (70%) hepatic IRI was induced in male C57BL/6 mice by portal triad pedicle occlusion for 45 minutes followed by reperfusion for 6 hours. Eupatilin (10 mg/kg body weight, oral) was administered 4 days before the IRI. Treatment with eupatilin significantly decreased serum alanine aminotransferase and serum aspartate aminotransferase as well as liver histological changes. Eupatilin also prevented hepatic glutathione depletion and increased malondialdehyde levels induced by IRI. Western blotting indicated that eupatilin significantly increased the levels of heat shock protein 70 and B-cell lymphoma 2 protein, attenuated inducible nitric oxide synthase, and cleaved caspase-3 levels 6 hours after IRI. The expression of the toll-like receptor 2/4, and phosphorylated nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (p-IkB-α) was significantly decreased in the eupatilin pretreatment group. Eupatilin improved the acute hepatic IRI by reducing inflammation and apoptosis. These findings suggest that eupatilin is a promising therapeutic agent against acute IR-induced hepatic damage.