Down-regulation of nuclear HMGB1 reduces ischemia-induced HMGB1 translocation and release and protects against liver ischemia-reperfusion injury

Ac2-26 reduced the liver injury after cardiopulmonary bypass in rats via AKT1/GSK3β/eNOS pathway

OBJECTIVE

About 10% of patients after cardiopulmonary bypass (CPB) would undergo acute liver injury, which aggravated the mortality of patients. Ac2-26 has been demonstrated to ameliorate organic injury by inhibiting inflammation. The present study aims to evaluate the effect and mechanism of Ac2-26 on acute liver injury after CPB.

METHODS

A total of 32 SD rats were randomized into sham, CPB, Ac, and Ac/AKT1 groups. The rats only received anesthesia, and rats in other groups received CPB. The rats in Ac/AKT1 were pre-injected with the shRNA to interfere with the expression of AKT1. The rats in CPB were injected with saline, and rats in Ac and Ac/AKT1 groups were injected with Ac2-26. After 12 h of CPB, all the rats were sacrificed and the peripheral blood and liver samples were collected to analyze. The inflammatory factors in serum and liver were detected. The liver function was tested, and the pathological injury of liver tissue was evaluated.

RESULTS

Compared with the sham group, the inflammatory factors, liver function, and pathological injury were worsened after CPB. Compared with the CPB group, the Ac2-26 significantly decreased the pro-inflammatory factors and increased the anti-inflammatory factor, improved liver function, and ameliorated the pathological injury. All the therapeutic effects of Ac2-26 were notably attenuated by the shRNA of AKT1. The Ac2-26 increased the GSK3β and eNOS, and this promotion was inhibited by the shRNA.

CONCLUSION

The Ac2-26 significantly treated the liver injury, inhibited inflammation, and improved liver function. The effect of Ac2-26 on liver injury induced by CPB was partly associated with the promotion of AKT1/GSK3β/eNOS.

Emerging role of regulated cell death in intestinal failure-associated liver disease

Intestinal failure-associated liver disease (IFALD) is a common complication of long-term parenteral nutrition that is associated with significant morbidity and mortality. It is mainly characterized by cholestasis in children and steatohepatitis in adults. Unfortunately, there is no effective approach to prevent or reverse the disease. Regulated cell death (RCD) represents a fundamental biological paradigm that determines the outcome of a variety of liver diseases. Nowadays cell death is reclassified into several types, based on the mechanisms and morphological phenotypes. Emerging evidence has linked different modes of RCD, such as apoptosis, necroptosis, ferroptosis, and pyroptosis to the pathogenesis of liver diseases. Recent studies have shown that different modes of RCD are present in animal models and patients with IFALD. Understanding the pathogenic roles of cell death may help uncover the underlying mechanisms and develop novel therapeutic strategies in IFALD. In this review, we discuss the current knowledge on how RCD may link to the pathogenesis of IFALD. We highlight examples of cell death-targeted interventions aiming to attenuate the disease, and provide perspectives for future basic and translational research in the field.

Focusing on Ischemic Reperfusion Injury in the New Era of Dynamic Machine Perfusion in Liver Transplantation

Liver transplantation is the most effective treatment for end-stage liver disease. Transplant indications have been progressively increasing, with a huge discrepancy between the supply and demand of optimal organs. In this context, the use of extended criteria donor grafts has gained importance, even though these grafts are more susceptible to ischemic reperfusion injury (IRI). Hepatic IRI is an inherent and inevitable consequence of all liver transplants; it involves ischemia-mediated cellular damage exacerbated upon reperfusion and its severity directly affects graft function and post-transplant complications. Strategies for organ preservation have been constantly improving since they first emerged. The current gold standard for preservation is perfusion solutions and static cold storage. However, novel approaches that allow extended preservation times, organ evaluation, and their treatment, which could increase the number of viable organs for transplantation, are currently under investigation. This review discusses the mechanisms associated with IRI, describes existing strategies for liver preservation, and emphasizes novel developments and challenges for effective organ preservation and optimization.

Carbon dot nanozymes as free radicals scavengers for the management of hepatic ischemia-reperfusion injury by regulating the liver inflammatory network and inhibiting apoptosis

BACKGROUND

Hepatic ischemia-reperfusion injury (HIRI) is a pathophysiological process during liver transplantation, characterized by insufficient oxygen supply and subsequent restoration of blood flow leading to an overproduction of reactive oxygen species (ROS), which in turn activates the inflammatory response and leads to cellular damage. Therefore, reducing excess ROS production in the hepatic microenvironment would provide an effective way to mitigate oxidative stress injury and apoptosis during HIRI. Nanozymes with outstanding free radical scavenging activities have aroused great interest and enthusiasm in oxidative stress treatment.

RESULTS

We previously demonstrated that carbon-dots (C-dots) nanozymes with SOD-like activity could serve as free radicals scavengers. Herein, we proposed that C-dots could protect the liver from ROS-mediated inflammatory responses and apoptosis in HIRI, thereby improving the therapeutic effect. We demonstrated that C-dots with anti-oxidative stress and anti-inflammatory properties improved the survival of L-02 cells under H2O2 and LPS-treated conditions. In the animal model, Our results showed that the impregnation of C-dots could effectively scavenge ROS and reduce the expression of inflammatory cytokines, such as IL-1β, IL-6, IL-12, and TNF-α, resulting in a profound therapeutic effect in the HIRI. To reveal the potential therapeutic mechanism, transcriptome sequencing was performed and the relevant genes were validated, showing that the C-dots exert hepatoprotective effects by modulating the hepatic inflammatory network and inhibiting apoptosis.

CONCLUSIONS

With negligible systemic toxicity, our findings substantiate the potential of C-dots as a therapeutic approach for HIRI, thereby offering a promising intervention strategy for clinical implementation.

Liver ischemia-reperfusion injury: From trigger loading to shot firing

An ischemia-reperfusion injury (IRI) results from a prolonged ischemic insult followed by the restoration of blood perfusion, being a common cause of morbidity and mortality, especially in liver transplantation. At the maximum of the potential damage, IRI is characterized by 2 main phases. The first is the ischemic phase, where the hypoxia and vascular stasis induces cell damage and the accumulation of damage-associated molecular patterns and cytokines. The second is the reperfusion phase, where the local sterile inflammatory response driven by innate immunity leads to a massive cell death and impaired liver functionality. The ischemic time becomes crucial in patients with underlying pathophysiological conditions. It is possible to compare this process to a shooting gun, where the loading trigger is the ischemia period and the firing shot is the reperfusion phase. In this optic, this article aims at reviewing the main ischemic events following the phases of the surgical timeline, considering the consequent reperfusion damage.

Deficiency of neutrophil high-mobility group box-1 in liver transplant recipients exacerbates early allograft injury in mice

BACKGROUND AND AIMS

Early allograft dysfunction (EAD) is a severe event leading to graft failure after liver transplant (LT). Extracellular high-mobility group box-1 (HMGB1) is a damage-associated molecular pattern that contributes to hepatic ischemia-reperfusion injury (IRI). However, the contribution of intracellular HMGB1 to LT graft injury remains elusive. We hypothesized that intracellular neutrophil-derived HMGB1 from recipients protects from post-LT EAD.

APPROACH AND RESULTS

We generated mice with conditional ablation or overexpression of Hmgb1 in hepatocytes, myeloid cells, or both. We performed LTs and injected lipopolysaccharide (LPS) to evaluate the effect of intracellular HMGB1 in EAD. Ablation of Hmgb1 in hepatocytes and myeloid cells of donors and recipients exacerbated early allograft injury after LT. Ablation of Hmgb1 from liver grafts did not affect graft injury; however, lack of Hmgb1 from recipient myeloid cells increased reactive oxygen species (ROS) and inflammation in liver grafts and exacerbated injury. Neutrophils lacking HMGB1 were more activated, showed enhanced pro-oxidant and pro-inflammatory signatures, and reduced biosynthesis and metabolism of inositol polyphosphates (InsPs). On LT reperfusion or LPS treatment, there was significant neutrophil mobilization and infiltration into the liver and enhanced production of ROS and pro-inflammatory cytokines when intracellular Hmgb1 was absent. Depletion of neutrophils using anti-Ly6G antibody attenuated graft injury in recipients with myeloid cell Hmgb1 ablation.

CONCLUSIONS

Neutrophil HMGB1 derived from recipients is central to regulate their activation, limits the production of ROS and pro-inflammatory cytokines, and protects from early liver allograft injury.

Assessing Donor Liver Quality and Restoring Graft Function in the Era of Extended Criteria Donors

Liver transplantation (LT) is the final treatment option for patients with end-stage liver disease. The increasing donor shortage results in the wide usage of grafts from extended criteria donors across the world. Using such grafts is associated with the elevated incidences of post-transplant complications including initial nonfunction and ischemic biliary tract diseases, which significantly reduce recipient survival. Although several clinical factors have been demonstrated to impact donor liver quality, accurate, comprehensive, and effective assessment systems to guide decision-making for organ usage, restoration or discard are lacking. In addition, the development of biochemical technologies and bioinformatic analysis in recent years helps us better understand graft injury during the perioperative period and find potential ways to restore graft function. Moreover, such advances reveal the molecular profiles of grafts or perfusate that are susceptible to poor graft function and provide insight into finding novel biomarkers for graft quality assessment. Focusing on donors and grafts, we updated potential biomarkers in donor blood, liver tissue, or perfusates that predict graft quality following LT, and summarized strategies for restoring graft function in the era of extended criteria donors. In this review, we also discuss the advantages and drawbacks of these potential biomarkers and offer suggestions for future research.

Protective effect of pinocembrin from Penthorum chinense Pursh on hepatic ischemia reperfusion injury via regulating HMGB1/TLR4 signal pathway

Hepatic ischemia-reperfusion injury (HIRI) is of common occurrence during liver surgery and transplantation. Pinocembrin (PIN) is a kind of flavonoid monomer extracted from the local traditional Chinese medicine Penthorum chinense Pursh (P. chinense). However, the effect of PIN on HIRI has not determined. We investigated the protective effect and potential mechanism of PIN against HIRI. Model mice were subjected to partial liver ischemia for 60 min, experimental mice were pretreated with PIN orally for 7 days, and H₂ O₂ -induced oxidative damage model in AML12 hepatic cells was established in vitro. Histopathologic analysis and serum biochemical levels revealed that PIN had hepatoprotective activities against HIRI. The variation of GSH, SOD, MDA, and ROS levels indicated that PIN treatments attenuated oxidative stress in tissue. PIN pretreatment obviously ameliorated apoptosis, and restrained the expression of HMGB1 and TLR4 in vivo. In vitro, compared with H₂ O₂ group, the contents of ROS, mitochondrial membrane potential, apoptotic cells, and Bcl-2 protein were decreased, while the Bax protein expression was increased. Moreover, HMGB-1 small interfering RNA test and western blotting showed that PIN pretreatment reduced HMGB1 and TLR4 protein levels. In conclusion, PIN pretreatment effectively protected hepatocytes from HIRI and inhibited the HMGB1/TLR4 signaling pathway.

Effects of iNOS in Hepatic Warm Ischaemia and Reperfusion Models in Mice and Rats: A Systematic Review and Meta-Analysis

Warm ischaemia is usually induced by the Pringle manoeuver (PM) during hepatectomy. Currently, there is no widely accepted standard protocol to minimise ischaemia-related injury, so reducing ischaemia-reperfusion damage is an active area of research. This systematic review and meta-analysis focused on inducible nitric oxide synthase (iNOS) as an early inflammatory response to hepatic ischaemia reperfusion injury (HIRI) in mouse- and rat-liver models. A systematic search of studies was performed within three databases. Studies meeting the inclusion criteria were subjected to qualitative and quantitative synthesis of results. We performed a meta-analysis of studies grouped by different HIRI models and ischaemia times. Additionally, we investigated a possible correlation of endothelial nitric oxide synthase (eNOS) and nitric oxide (NO) regulation with iNOS expression. Of 124 included studies, 49 were eligible for the meta-analysis, revealing that iNOS was upregulated in almost all HIRIs. We were able to show an increase of iNOS regardless of ischemia or reperfusion time. Additionally, we found no direct associations of eNOS or NO with iNOS. A sex gap of primarily male experimental animals used was observed, leading to a higher risk of outcomes not being translatable to humans of all sexes.

Modifying organs with gene therapy and gene modulation in the age of machine perfusion

PURPOSE OF REVIEW

This review aims to highlight current advances in gene therapy methods, describing advances in CRISPR-Cas9 gene editing and RNA interference in relevance to liver transplantation, and machine perfusion.

RECENT FINDINGS

In order to minimize rejection, increase the donor pool of available organs, and minimize the effects of ischemia-reperfusion injury, gene therapy and gene modification strategies are, thus, required in the context of liver transplantation.

SUMMARY

Gene therapy has been used successfully in a diverse array of diseases, and, more recently, this technique has gained interest in the field of organ transplantation. Biological and logistical challenges reduce the rate of successful procedures, increasing the waiting list even more. We explore the exciting future implications of customized gene therapy in livers using machine perfusion, including its potential to create a future in which organs destined for transplant are individualized to maximize both graft and recipient longevity.

Pre-Ischemic Hypothermic Oxygenated Perfusion Alleviates Protective Molecular Markers of Ischemia-Reperfusion Injury in Rat Liver

To expand the pool of organs, hypothermic oxygenated perfusion (HOPE), one of the most promising perfusion protocols, is currently performed after cold storage (CS) at transplant centers (HOPE-END). We investigated a new timing for HOPE, hypothesizing that performing HOPE before CS (HOPE-PRE) could boost mitochondrial protection allowing the graft to better cope with the accumulation of oxidative stress during CS. We analyzed liver injuries at 3 different levels. Histologic analysis demonstrated that, compared to classical CS (CTRL), the HOPE-PRE group showed significantly less ischemic necrosis compared to CTRL vs HOPE-END. From a biochemical standpoint, transaminases were lower after 2 hours of reperfusion in the CTRL vs HOPE-PRE group, which marked decreased liver injury. qPCR analysis on 37 genes involved in ischemia-reperfusion injury revealed protection in HOPE-PRE and HOPE-END compared to CTRL mediated through similar pathways. However, the CTRL vs HOPE-PRE group demonstrated an increased transcriptional level for protective genes compared to the CTRL vs HOPE-END group. This study provides insights on novel biomarkers that could be used in the clinic to better characterize graft quality improving transplantation outcomes.

Delivering siRNA Compounds During HOPE to Modulate Organ Function: A Proof-of-Concept Study in a Rat Liver Transplant Model

BACKGROUND

Apoptosis contributes to the severity of ischemia-reperfusion injury (IRI), limiting the use of extended criteria donors in liver transplantation (LT). Machine perfusion has been proposed as a platform to administer specific therapies to improve graft function. Alternatively, the inhibition of genes associated with apoptosis during machine perfusion could alleviate IRI post-LT. The aim of the study was to investigate whether inhibition of an apoptosis-associated gene (FAS) using a small interfering RNA (siRNA) approach could alleviate IRI in a rat LT model.

METHODS

In 2 different experimental protocols, FASsiRNA (500 µg) was administered to rat donors 2 h before organ procurement, followed by 22 h of static cold storage, (SCS) or was added to the perfusate during 1 h of ex situ hypothermic oxygenated perfusion (HOPE) to livers previously preserved for 4 h in SCS.

RESULTS

Transaminase levels were significantly lower in the SCS-FASsiRNA group at 24 h post-LT. Proinflammatory cytokines (interleukin-2, C-X-C motif chemokine 10, tumor necrosis factor alpha, and interferon gamma) were significantly decreased in the SCS-FASsiRNA group, whereas the interleukin-10 anti-inflammatory cytokine was significantly increased in the HOPE-FASsiRNA group. Liver absorption of FASsiRNA after HOPE session was demonstrated by confocal microscopy; however, no statistically significant differences on the apoptotic index, necrosis levels, and FAS protein transcription between treated and untreated groups were observed.

CONCLUSIONS

FAS inhibition through siRNA therapy decreases the severity of IRI after LT in a SCS protocol; however the association of siRNA therapy with a HOPE perfusion model is very challenging. Future studies using better designed siRNA compounds and appropriate doses are required to prove the siRNA therapy effectiveness during liver HOPE liver perfusion.

The Effect of Hypothermic Machine Perfusion to Ameliorate Ischemia-Reperfusion Injury in Donor Organs

Hypothermic machine perfusion (HMP) has become the new gold standard in clinical donor kidney preservation and a promising novel strategy in higher risk donor livers in several countries. As shown by meta-analysis for the kidney, HMP decreases the risk of delayed graft function (DGF) and improves graft survival. For the liver, HMP immediately prior to transplantation may reduce the chance of early allograft dysfunction (EAD) and reduce ischemic sequelae in the biliary tract. Ischemia-reperfusion injury (IRI), unavoidable during transplantation, can lead to massive cell death and is one of the main causes for DGF, EAD or longer term impact. Molecular mechanisms that are affected in IRI include levels of hypoxia inducible factor (HIF), induction of cell death, endothelial dysfunction and immune responses. In this review we have summarized and discussed mechanisms on how HMP can ameliorate IRI. Better insight into how HMP influences IRI in kidney and liver transplantation may lead to new therapies and improved transplant outcomes.

Sodium butyrate ameliorates Schistosoma japonicum-induced liver fibrosis by inhibiting HMGB1 expression

Schistosomiasis is a prevalent zoonotic parasitic disease caused by schistosomes. Its main threat to human health is hepatic granuloma and fibrosis due to worm eggs. Praziquantel remains the first choice for the treatment of schistosomiasis but has limited benefit in treating liver fibrosis. Therefore, the need to develop effective drugs for treating schistosomiasis-induced hepatic fibrosis is urgent. High-mobility group box 1 protein (HMGB1) is a potential immune mediator that is highly associated with the development of some fibrotic diseases and may be involved in the liver pathology of schistosomiasis. We speculated that HMGB1 inhibitors could have an anti-fibrotic effect. Sodium butyrate (SB), a potent inhibitor of HMGB1, has shown anti-inflammatory activity in some animal disease models. In this study, we evaluated the effects of SB on a murine schistosomiasis model. Mice were percutaneously infected with 20 ± 2 cercariae of Schistosoma japonicum. SB (500 mg/kg/day) was administered every 3 days for the entire experiment period. The activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), liver histopathology, HMGB1 expression, and the levels of interferon gamma (IFN-γ), transforming growth factor-β1 (TGF-β1), and interleukin-6 (IL-6) in serum were analyzed. SB reduced hepatic granuloma and fibrosis of schistosomiasis, reflected by the decreased levels of ALT and AST in serum and the reduced expression of pro-inflammatory and fibrogenic cytokines (IFN-γ, TGF-β1, and IL-6). The protective effect could be attributable to the inhibition of the expression of HMGB1 and release by SB.

Liraglutide protects against lethal renal ischemia-reperfusion injury by inhibiting high-mobility group box 1 nuclear-cytoplasmic translocation and release

Liraglutide, a glucagon-like peptide-1 receptor (GLP-1R) agonist, has been reported to exert protective effects against myocardial, hepatic, and gastric ischemia-reperfusion injury (IRI), but whether it can protect against renal IRI remains unknown. Here, a lethal renal IRI model was established with a 100% mortality rate in untreated mice. Treatment with liraglutide involving a regimen of multiple doses resulted in 100% survival, remarkable preservation of renal function, a significant reduction in pathological damage, and blunted upregulation of TNF-α, IL-1β, IL-6, MCP-1, TLR-2, TLR-4, and RAGE mRNA. We found that liraglutide treatment dramatically inhibited ischemia-induced nucleocytoplasmic translocation and release of HMGB1. This inhibition was associated with a marked decrease (~ 60%) in nuclear histone acetyltransferase activity. In addition, the protective effects of liraglutide on renal IRI were largely abolished by the administration of exogenous HMGB1. When the GLP-1R antagonist exendin (9-39) was given to mice before each liraglutide administration, or GLP-1R-/- mice were used for the renal IRI experiments, the protective effect of liraglutide on renal IRI was partially reversed. Moreover, liraglutide pretreatment significantly inhibited HMGB1 nucleocytoplasmic translocation during hypoxic culture of HK-2 cells in vitro, but the addition of exendin (9-39) significantly eliminated this inhibition. We demonstrate here that liraglutide can exert a strong protective effect on lethal renal IRI in mice. This protection appears to be related to the inhibition of HMGB1 nuclear-cytoplasmic translocation and release and partially depends on GLP-1R. Thus, liraglutide may be therapeutically useful for the clinical prevention and treatment of organ IRI.

Identification of High-Mobility Group Box 1 (HMGB1) Expression as a Potential Predictor of Rejection and Poor Prognosis After Liver Transplantation

BACKGROUND Acute cellular rejection (ACR) frequently occurs after liver transplantation (LT) and can result in permanent damage of the liver allograft. Specific and sensitive biomarkers for predicting and monitoring ACR are vital for guiding post-transplantation care. In the present study, we aimed to investigate the function of high-mobility group box 1 (HMGB1) in predicting ACR and prognosis after LT. MATERIAL AND METHODS A total of 113 LT recipients were enrolled in the study, including 62 patients in an ACR group and 51 patients in a non-rejection group. Using tissues from the 113 patients, HMGB1 expression was examined by immunohistochemistry, and the total score for HMGB1 expression was calculated by multiplying the percentage of immunoreactive cells score and the staining intensity score. We then analyzed the association between HMGB1 expression and clinical features. Finally, the function of HMGB1 in predicting the prognosis of LT was determined using Kaplan-Meier (K-M) survival and Cox multivariate analyses. RESULTS Immunohistochemical staining results demonstrated that the expression of HMGB1 was significantly increased in the ACR group, compared with that in the non-rejection group (P<0.05). Clinical characteristic analysis revealed that high HMGB1 levels were related to ACR (P<0.05). Moreover, K-M survival analysis showed that patients with high HMGB1 expression displayed poorer prognosis (P<0.05). Cox multivariate analysis demonstrated that HMGB1 was an independent prognostic predictor for post-LT survival (odds ratio, 3.283; P=0.008). CONCLUSIONS LT recipients' HMGB1 levels may be a useful and noninvasive biomarker for the prediction of ACR and prognosis after LT.

Dexmedetomidine inhibits inflammatory response and oxidative stress through regulating miR-205-5p by targeting HMGB1 in cerebral ischemic/reperfusion

OBJECTIVE

To investigate effects of dexmedetomidine (DEX) on miR-205-5p/HMGB1 axis in cerebral ischemic/reperfusion (I/R) injury.

METHODS

Both in vivo I/R rat model and in vitro hypoxia/reoxygenation (H/R) cell model using rat hippocampal neurons cells were established. miR-205-5p was overexpressed or inhibited by transfection of miR-205-5p mimics or inhibitor. HMGB1 was overexpressed by transfection overexpression plasmids (OE-HMGB1). TTC staining was used for measurement of infraction volume. Oxidative stress was evaluated by measurement of reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) and inflammation was evaluated by measurement of IL-1β, IL-6 and TNF-α. Dual luciferase reporter assay was performed to confirm binding between miR-205-5p and HMGB1. The expression levels of miR-205-5p, and HMGB1 were measured using RT-qPCR. Western blotting was used to test the protein expression levels of HMGB1, nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione peroxidase (GPx), glutathione reductase (GR), heme oxygenase 1 (HO-1) and catalase (CAT).

RESULTS

Treatment of DEX significantly reduced brain infraction volume, decreased Longa's neurological function score and inhibited oxidative stress and inflammation in brain tissues of I/R rats, which were all reversed by inhibition of miR-205-5p. Both treatment of DEX or overexpression of miR-205-5p restricted oxidative stress and inflammation in H/R rat hippocampal neurons cells. The inhibition of miR-205-5p reversed the effects of DEX, while the overexpression of HMGB1 reversed the effects of miR-205-5p overexpression in H/R rat hippocampal neurons cells. Dual luciferase reporter assay showed miR-205-5p directly targeted HMGB1.

CONCLUSION

DEX improved I/R injury by suppressing brain oxidative stress and inflammation DEX improved I/R injury by suppressing brain oxidative stress and inflammation through activating miR-205-5p/HMGB1 axis through activating miR-205-5p/HMGB1 axis.

HMGB1 signaling-regulated endoplasmic reticulum stress mediates intestinal ischemia/reperfusion-induced acute renal damage

BACKGROUND

Ischemia/reperfusion of the intestine often leads to distant organ injury, but the mechanism of intestinal ischemia/reperfusion-induced renal dysfunction is still not clear. The present study aimed to investigate the mechanisms of acute renal damage after intestinal ischemia/reperfusion challenge and explore the role of released high-mobility group box-1 in this process.

METHODS

Intestinal ischemia/reperfusion was induced in male Sprague-Dawley rats by clamping the superior mesenteric artery for 1.5 hours. At different reperfusion time points, anti-high-mobility group box-1 neutralizing antibodies or ethyl pyruvate were administered to neutralize or inhibit circulating high-mobility group box-1, respectively.

RESULTS

Significant kidney injury was observed after 6 hours of intestinal reperfusion, as indicated by increased serum levels of urea nitrogen and creatinine, increased expression of neutrophil gelatinase-associated lipocalin, interleukin-6, and MIP-2, and enhanced cell apoptosis, as indicated by cleaved caspase 3 levels in renal tissues. The levels of phosphorylated eIF2ɑ, activating transcription factor 4, and C/EBP-homologous protein (CHOP) were markedly elevated, indicating the activation of endoplasmic reticulum stress in the impaired kidney. High-mobility group box-1 translocated to cytoplasm in the intestine and serum concentrations of high-mobility group box-1 increased notably during the reperfusion phase. Both anti-high-mobility group box-1 antibodies and ethyl pyruvate treatment significantly reduced serum high-mobility group box-1 concentrations, attenuated endoplasmic reticulum stress in renal tissue and inhibited the development of renal damage. Moreover, the elevated expression of receptor for advanced glycation end products in the kidneys after intestinal ischemia/reperfusion was abrogated after high-mobility group box-1 inhibition.

CONCLUSION

These results suggested that high-mobility group box-1 signaling regulated endoplasmic reticulum stress and promoted intestinal ischemia/reperfusion-induced acute kidney injury. High-mobility group box-1 neutralization/inhibition might serve as a pharmacological intervention strategy for these pathophysiological processes.

Nanotheranostics for the Management of Hepatic Ischemia-Reperfusion Injury

Hepatic ischemia-reperfusion injury (IRI), in which an insufficient oxygen supply followed by reperfusion leads to an inflammatory network and oxidative stress in disease tissue to cause cell death, always occurs after liver transplantations and sections. Although pharmacological treatments favorably prevent or protect the liver against experimental IRI, there have been few successes in clinical applications for patient benefits because of the incomprehension of complicated IRI-induced signaling events as well as short blood circulation time, poor solubility, and severe side reactions of most antioxidants and anti-inflammatory drugs. Nanomaterials can achieve targeted delivery and controllable release of contrast agents and therapeutic drugs in desired hepatic IRI regions for enhanced imaging sensitivity and improved therapeutic effects, emerging as novel alternative approaches for hepatic IRI diagnosis and therapy. In this review, the application of nanotechnology is summarized in the management of hepatic IRI, including nanomaterial-assisted hepatic IRI diagnosis, nanoparticulate systems-mediated remission of reactive oxygen species-induced tissue injury, and nanoparticle-based targeted drug delivery systems for the alleviation of IRI-related inflammation. The current challenges and future perspectives of these nanoenabled strategies for hepatic IRI treatment are also discussed.

Drug delivery nanosystems targeted to hepatic ischemia and reperfusion injury

Hepatic ischemia and reperfusion injury (IRI) is an acute inflammatory process that results from surgical interventions, such as liver resection surgery or transplantation, or hemorrhagic shock. This pathology has become a severe clinical issue, due to the increasing incidence of hepatic cancer and the high number of liver transplants. So far, an effective treatment has not been implemented in the clinic. Despite its importance, hepatic IRI has not attracted much interest as an inflammatory disease, and only a few reviews addressed it from a therapeutic perspective with drug delivery nanosystems. In the last decades, drug delivery nanosystems have proved to be a major asset in therapy because of their ability to optimize drug delivery, either by passive or active targeting. Passive targeting is achieved through the enhanced permeability and retention (EPR) effect, a main feature in inflammation that allows the accumulation of the nanocarriers in inflammation sites, enabling a higher efficacy of treatment than conventional therapies. These systems also can be actively targeted to specific compounds, such as inflammatory markers and overexpressed receptors in immune system intermediaries, allowing an even more specialized therapy that have already showed encouraging results. In this manuscript, we review drug delivery nanosystems designed for hepatic IRI treatment, addressing their current state in clinical trials, discussing the main hurdles that hinder their successful translation to the market and providing some suggestions that could potentially advance their clinical translation.

The effects of meldonium on the acute ischemia/reperfusion liver injury in rats

Acute ischemia/reperfusion (I/R) liver injury is a clinical condition challenging to treat. Meldonium is an anti-ischemic agent that shifts energy production from fatty acid oxidation to less oxygen-consuming glycolysis. Thus, we investigated the effects of a 4-week meldonium pre-treatment (300 mg/kg b.m./day) on the acute I/R liver injury in Wistar strain male rats. Our results showed that meldonium ameliorates I/R-induced liver inflammation and injury, as confirmed by liver histology, and by attenuation of serum alanine- and aspartate aminotransferase activity, serum and liver high mobility group box 1 protein expression, and liver expression of Bax/Bcl2, haptoglobin, and the phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells. Through the increased hepatic activation of the nuclear factor erythroid 2-related factor 2, meldonium improves the antioxidative defence in the liver of animals subjected to I/R, as proved by an increase in serum and liver ascorbic/dehydroascorbic acid ratio, hepatic haem oxygenase 1 expression, glutathione and free thiol groups content, and hepatic copper-zinc superoxide dismutase, manganese superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activity. Based on our results, it can be concluded that meldonium represent a protective agent against I/R-induced liver injury, with a clinical significance in surgical procedures.

Aucubin Attenuates Liver Ischemia-Reperfusion Injury by Inhibiting the HMGB1/TLR-4/NF-κB Signaling Pathway, Oxidative Stress, and Apoptosis

Liver ischemia-reperfusion injury (IRI) is a common clinical event with high morbidity in patients undergoing complex liver surgery or having abdominal trauma. Inflammatory and oxidative stress responses are the main contributing factors in liver IRI. The iridoid glucoside aucubin (AU) has good anti-inflammatory and antioxidative effects; however, there are no relevant reports on the protective effect of glucosides on hepatic IRI. The purpose of this study was to determine whether AU pretreatment could prevent liver IRI and to explore the mechanism. Sprague–Dawley rats were randomly divided into five groups. The sham operation and IRI control groups were given intraperitoneal injections of normal saline, while the AU low-dose (AU-L) group, AU medium-dose (AU-M) group, and AU high-dose (AU-H) group were given intraperitoneal injections of AU at doses of 1, 5, and 10 mg/kg/day, respectively. After 10 d, liver IRI (70% liver ischemia for 1 h, reperfusion for 6 h) was surgically established in all groups except the sham group. Our results confirmed that liver injury was significantly aggravated after hepatic ischemia-reperfusion. AU alleviated the increase of transaminase and pathological changes induced by ischemia-reperfusion and improved liver damage. AU could also ameliorate the inflammatory and oxidative stress responses induced by ischemia-reperfusion and reduced expression of high mobility group protein (HMG)B1, receptor for advanced glycation end-products (RAGE), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and reactive oxygen species (ROS). Moreover, AU reduced ischemia-reperfusion-induced mitochondrial dysfunction and cells apoptosis, increased peroxisome proliferator-activated receptor γ coactivator (PGC)-1α and uncoupling (UCP)2 protein expression, and reduced caspase-3, cleaved caspase-3, and Cytochrome P450 proteins (CYP) expression. To determine expression levels of the Toll-like receptor (TLR)-4/nuclear factor-κB (NF-κB) pathway-related proteins in vitro and in vivo, we also measured TLR-4, myeloid differentiation factor88 (MyD88), NF-κB P65, p-P65, I-kappa-B-alpha (IκB-α), and p-IκB-α levels. The results showed that AU effectively inhibited activation of the TLR-4/NF-κB signaling pathway. In conclusion, we showed for the first time a hepatoprotective effect for AU in liver IRI, which acted by inhibiting the HMGB1/TLR-4/NF-κB signaling pathway, oxidative stress, and apoptosis. Pretreatment with AU may be a promising strategy for preventing liver IRI.

Necroptosis in Hepatosteatotic Ischaemia-Reperfusion Injury

While liver transplantation remains the sole treatment option for patients with end-stage liver disease, there are numerous limitations to liver transplantation including the scarcity of donor livers and a rise in livers that are unsuitable to transplant such as those with excess steatosis. Fatty livers are susceptible to ischaemia-reperfusion (IR) injury during transplantation and IR injury results in primary graft non-function, graft failure and mortality. Recent studies have described new cell death pathways which differ from the traditional apoptotic pathway. Necroptosis, a regulated form of cell death, has been associated with hepatic IR injury. Receptor-interacting protein kinase 3 (RIPK3) and mixed-lineage kinase domain-like pseudokinase (MLKL) are thought to be instrumental in the execution of necroptosis. The study of hepatic necroptosis and potential therapeutic approaches to attenuate IR injury will be a key factor in improving our knowledge regarding liver transplantation with fatty donor livers. In this review, we focus on the effect of hepatic steatosis during liver transplantation as well as molecular mechanisms of necroptosis and its involvement during liver IR injury. We also discuss the immune responses triggered during necroptosis and examine the utility of necroptosis inhibitors as potential therapeutic approaches to alleviate IR injury.

MTMR14 protects against hepatic ischemia-reperfusion injury through interacting with AKT signaling in vivo and in vitro

Hepatic ischemia-reperfusion (IR) injury is characterized by severe inflammation and cell death. However, very few effective therapies are presently available for hepatic IR injury treatment. Here, we reported a protective function and the underlying mechanism of myotubularin-related protein 14 (MTMR14) during hepatic IR injury. Hepatocyte-specific MTMR14 knockout (HKO) and transgenic (TG) mice were subjected to hepatic IR operation to explore MTMR14 function in vivo. Primary hepatocytes isolated from MTMR14-HKO and MTMR14-TG mice were subjected to hypoxia/reoxygenation (HR) insult in vitro. We found that MTMR14 expression in liver tissues from individuals with hepatic IR was markedly decreased, and similar results were detected in mice with hepatic IR surgery. MTMR14-TG mice following hepatic IR operation had obviously ameliorated liver pathological changes, along with improved hepatic dysfunction, which was proved by the decreased serum alanine amino transferase (ALT) and aspartate amino transferase (AST) levels. MTMR14-HKO and MTMR14-TG animal models indicated that MTMR14 alleviated cell death and inflammatory response. In addition, MTMR14 inhibited nuclear transcription factor κB (NF-κB) signaling. Of note, promoting MTMR14 expression improved phosphatidylinositol 3-kinase/protein kinase-B (PI3K/AKT) pathway through a physical interaction with AKT, subsequently reducing cell death and inflammation. Therefore, MTMR14 is a protective factor during hepatic IR injury, and the MTMR14/AKT signaling is involved the pathogenesis hepatic IR injury. Improvement of this axis might be a novel therapeutic strategy for the prevention of this pathological process.

Quercetin Attenuates d-GaLN-Induced L02 Cell Damage by Suppressing Oxidative Stress and Mitochondrial Apoptosis via Inhibition of HMGB1

High mobility group box-1 (HMGB1) plays an important role in various liver injuries. In the case of acute liver injury, it leads to aseptic inflammation and other reactions, and also regulates specific cell death responses in chronic liver injury. HMGB1 has been demonstrated to be a good therapeutic target for treating liver failure. Quercetin (Que), as an antioxidant, is a potential phytochemical with hepatocyte protection and is also considered to be an inhibitor of HMGB1. However, the mechanism of its hepatoprotective effects remains to be characterized. The present study explored whether the hepatoprotective effect of Que antagonizes HMGB1, and subsequent molecular signaling events. Our results indicated that Que protects L02 cells from d-galactosamine (d-GaLN)-induced cellular damage by reducing intracellular reactive oxygen species (ROS) production and apoptotic responses in the mitochondrial pathway. Immunofluorescence and Western blot assays showed that HMGB1 was involved in d-GaLN-induced L02 cell damage. Further research showed that after transfection with HMGB1 short hairpin RNA (shRNA), cell viability was improved, and intracellular ROS production and apoptosis were suppressed. When co-treated with Que, the expression of HMGB1 was decreased significantly, the expression of proteins in the corresponding signal pathway were further reduced, and the production of ROS and apoptosis were further suppressed. Molecular docking also indicated the binding of Que and HMGB1. Taken together, these results indicate that Que significantly improves d-GaLN-induced cellular damage by inhibiting oxidative stress and mitochondrial apoptosis via inhibiting HMGB1.

RNA interference therapeutics in organ transplantation: The dawn of a new era

RNA interference (RNAi) is a natural process through which double-stranded RNA molecules can silence the gene carrying the same code as the particular RNA of interest. In 2006, the discovery of RNAi was awarded the Nobel Prize in Medicine and its success has accumulated since. Gene silencing through RNAi has been used successfully in a broad range of diseases, and, more recently, this technique has gained interest in the field of organ transplantation. Here, genes related to ischemia-reperfusion injury (IRI) or graft rejection may be silenced to improve organ quality after transplantation. Several strategies have been used to deliver siRNA, and pretransplant machine perfusion presents a unique opportunity to deliver siRNA to the target organ during ex situ preservation. In this review, the potential of RNAi in the field of organ transplantation will be discussed. A brief overview on the discovery of RNAi, its mechanism, and limitations are included. In addition, studies using RNAi to target genes related to IRI in liver, kidney, lung, and heart transplantation are discussed.

Remote Ischemic Preconditioning and Diazoxide Protect from Hepatic Ischemic Reperfusion Injury by Inhibiting HMGB1-Induced TLR4/MyD88/NF-κB Signaling

Remote ischemic preconditioning (RIPC) is known to have a protective effect against hepatic ischemia-reperfusion (IR) injury in animal models. However, the underlying mechanism of action is not clearly understood. This study examined the effectiveness of RIPC in a mouse model of hepatic IR and aimed to clarify the mechanism and relationship of the ATP-sensitive potassium channel (K_ATP) and HMGB1-induced TLR4/MyD88/NF-κB signaling. C57BL/6 male mice were separated into six groups: (i) sham-operated control, (ii) IR, (iii) RIPC+IR, (iv) RIPC+IR+glyburide (K_ATP blocker), (v) RIPC+IR+diazoxide (K_ATP opener), and (vi) RIPC+IR+diazoxide+glyburide groups. Histological changes, including hepatic ischemia injury, were assessed. The levels of circulating liver enzymes and inflammatory cytokines were measured. Levels of apoptotic proteins, proinflammatory factors (TLR4, HMGB1, MyD88, and NF-κB), and IκBα were measured by Western blot and mRNA levels of proinflammatory cytokine factors were determined by RT-PCR. RIPC significantly decreased hepatic ischemic injury, inflammatory cytokine levels, and liver enzymes compared to the corresponding values observed in the IR mouse model. The K_ATP opener diazoxide + RIPC significantly reduced hepatic IR injury demonstrating an additive effect on protection against hepatic IR injury. The protective effect appeared to be related to the opening of K_ATP, which inhibited HMGB1-induced TRL4/MyD88/NF-kB signaling.

The Effects of Meldonium on the Renal Acute Ischemia/Reperfusion Injury in Rats

Acute renal ischemia/reperfusion (I/R) injury is a clinical condition that is challenging to treat. Meldonium is an anti-ischemic agent that shifts energy production from fatty acid oxidation to less oxygen-consuming glycolysis. Thus, in this study we investigated the effects of a four-week meldonium pre-treatment (300 mg/kg b.m./day) on acute renal I/R in male rats (Wistar strain). Our results showed that meldonium decreased animal body mass gain, food and water intake, and carnitine, glucose, and lactic acid kidney content. In kidneys of animals subjected to I/R, meldonium increased phosphorylation of mitogen-activated protein kinase p38 and protein kinase B, and increased the expression of nuclear factor erythroid 2-related factor 2 and haeme oxygenase 1, causing manganese superoxide dismutase expression and activity to increase, as well as lipid peroxidation, cooper-zinc superoxide dismutase, glutathione peroxidase, and glutathione reductase activities to decrease. By decreasing the kidney Bax/Bcl2 expression ratio and kidney and serum high mobility group box 1 protein content, meldonium reduced apoptotic and necrotic events in I/R, as confirmed by kidney histology. Meldonium increased adrenal noradrenaline content and serum, adrenal, hepatic, and renal ascorbic/dehydroascorbic acid ratio, which caused complex changes in renal lipidomics. Taken together, our results have confirmed that meldonium pre-treatment protects against I/R-induced oxidative stress and apoptosis/necrosis.

Human Mesenchymal Stromal Cell-Derived Extracellular Vesicles Improve Liver Regeneration After Ischemia Reperfusion Injury in Mice

Hepatic ischemia reperfusion injury (IRI) remains a major obstacle in liver resection and transplantation surgery, especially in diseased organs. Human mesenchymal stromal cells (MSCs) are reported to acutely alleviate hepatic IRI in mice by releasing bioactive membrane-enclosed extracellular vesicles (EVs), but the long-term effects of MSC-derived EV on hepatic IRI are unknown. Given the considerable differentiation capacity of fibroblasts (FBs) during wound healing and their morphological similarities with MSC, the present study aimed to investigate the potential of these two cell types and their cell-derived EV in attenuating liver damage after IRI. EVs were isolated and purified from the supernatant of MSC and FB cultures and, subsequently, characterized by electron microscopy, nanoparticle tracking analysis, and western blot. Liver injury and organ regeneration in a murine in vivo model of IRI were assessed by serum transaminase levels, histopathology, and immunohistochemistry. Changes in expression of inflammation-associated genes within liver tissue were evaluated by reverse transcriptase quantitative polymerase chain reaction. MSC, MSC-derived EV, FB, and FB-derived EV were systemically administered before hepatic IRI. We found that MSC and MSC-derived EV decreased serum transaminase levels, reduced hepatic necrosis, increased the amount of Ki67-positive hepatocytes, and repressed the transcription of inflammation-associated genes. Although they had no impact on organ damage, FB and FB-derived EV showed some regenerative potential in the late phase of hepatic IRI. Compared to FB, MSC and their derived EV had a stronger potential to attenuate liver damage and improve organ regeneration after hepatic IRI. These results suggest that the key therapeutic factors are located within EV.

Comparative study on protective effect of hydrogen rich saline and adipose-derived stem cells on hepatic ischemia-reperfusion and hepatectomy injury in swine

AIM

To compare and evaluate the hepatoprotective effect of liver parenchyma injection of ADSCs and portal vein injection of HRS in laparoscopic hepatic ischemia reperfusion combined with hepatectomy injury in miniature pigs.

METHODS

Eighteen miniature pigs were randomly assigned to IRI group, HRS group and ADSCs group. HRS was injected through the portal vein 10 min before reperfusion, 1 d, 2 d, and 3 d after surgery. ADSCs were injected into liver parenchyma after hepatectomy. The serum and liver tissue samples were collected at different time points (preoperative, and postoperative at 1 d, 3 d and 7 d).

RESULTS

Compared with the IRI group, both ADSCs and HRS groups can promote liver function recovery, reduce oxidative stress, reduce inflammation, and promote liver regeneration. Compared with HRS, ALT and TBIL in ADSCs group were significantly decreased at 3 d, and AST was significantly reduced at 1 d. The activities of SOD and GSH-Px in ADSCs group were significantly higher than that in HRS group, but the MDA level in HRS group was markedly lower than that in ADSCs group at 1 d. IL-1β was significantly lower in the ADSCs group than in the HRS group at 1 day after operation. The expressions of HGF and PCNA were significantly higher than that in the HRS group at 3 day after surgery.

CONCLUSION

Our study has demonstrated that HRS and ADSCs have significant hepatoprotective effects in miniature pigs after HIRI and hepatectomy injury. However, liver parenchyma injection of ADSCs is more beneficial to the recovery of liver function than portal vein injection of HRS.

Necroptotic Cell Death in Liver Transplantation and Underlying Diseases: Mechanisms and Clinical Perspective

Cell death is a natural process for the turnover of aged cells, but it can also arise as a result of pathological conditions. Cell death is recognized as a key feature in both acute and chronic hepatobiliary diseases caused by drug, alcohol, and fat uptake; by viral infection; or after surgical intervention. In the case of chronic disease, cell death can lead to (chronic) secondary inflammation, cirrhosis, and the progression to liver cancer. In liver transplantation, graft preservation and ischemia/reperfusion injury are associated with acute cell death. In both cases, so-called programmed cell death modalities are involved. Several distinct types of programmed cell death have been described of which apoptosis and necroptosis are the most well known. Parenchymal liver cells, including hepatocytes and cholangiocytes, are susceptible to both apoptosis and necroptosis, which are triggered by distinct signal transduction pathways. Apoptosis is dependent on a proteolytic cascade of caspase enzymes, whereas necroptosis induction is caspase-independent. Moreover, different from the "silent" apoptotic cell death, necroptosis can cause a secondary inflammatory cascade, so-called necroinflammation, triggered by the release of various damage-associated molecular patterns (DAMPs). These DAMPs activate the innate immune system, leading to both local and systemic inflammatory responses, which can even cause remote organ failure. Therapeutic targeting of necroptosis by pharmacological inhibitors, such as necrostatin-1, shows variable effects in different disease models.

TAK242 suppresses the TLR4 signaling pathway and ameliorates DCD liver IRI in rats

Ischemia-reperfusion injury (IRI) is a notable cause of tissue damage during surgical procedures and a major risk factor in graft dysfunction in liver transplantation. Livers obtained from donors after circulatory death (DCD) are prone to IRI and toll-like receptor 4 (TLR4) serves a prominent role in the inflammatory response associated with DCD liver IRI. The present study was designed to investigate whether TAK242, a specific TLR4 inhibitor, improves hepatic IRI following a DCD graft and to investigate its underlying protective mechanisms. Male Sprague-Dawley rats were randomized into 4 groups: Control, TAK242, DCD and DCD+TAK242 groups. Rats were pretreated with TAK242 or its vehicle for 30 min, then the livers were harvested without warm ischemia (control group and TAK242 group) or with warm ischemia in situ for 30 min. The livers were stored in cold University of Wisconsin solution for 24 h and subsequently perfused for 60 min with an isolated perfused rat liver system. Rat liver injury was evaluated thereafter. When compared with the DCD group, DCD livers with TAK242 pretreatment displayed significantly improved hepatic tissue injury and less tissue necrosis (P<0.05). Compared with DCD livers, mechanistic experiments revealed that TAK242 pretreatment alleviated mitochondrial dysfunction, reduced reactive oxygen species and malondialdehyde levels and inhibited apoptosis. Additionally, TAK242 significantly inhibited the IRI-associated inflammatory response, indicated by the decreased expression of TLR4, interleukin (IL)-1β, IL-6 and cyclooxygenase 2 at the mRNA and protein levels (P<0.05). TAK242 ameliorates DCD liver IRI via suppressing the TLR4 signaling pathway in rats. The results of the present study have revealed that TAK242 pretreatment harbors a potential benefit for liver transplantation.

Association between Early Acute Respiratory Distress Syndrome after Living-Donor Liver Transplantation and Perioperative Serum Biomarkers: The Role of Club Cell Protein 16

Background

Acute respiratory distress syndrome (ARDS) after living-donor liver transplantation (LDLT) is not uncommon, but it lacks the biomarkers for early detection. Club cell protein 16 (CC16), high-motility group box 1 protein (HMGB1), interleukin-1β (IL-1β), and IL-10 have been reported as relevant to the development of ARDS. However, they have not been investigated during LDLT.

Methods

Seventy-three consecutive recipients undergoing LDLT were enrolled and received the same perioperative care plan. Perioperative serum CC16, HMGB1, IL-1β, and IL-10 levels were measured at the pretransplant state, 30 minutes after reperfusion, postoperative day 1 (POD1), and POD3. ARDS was diagnosed according to the 2012 Berlin definition.

Results

Of the 73 recipients, 13 developed ARDS with significantly longer durations of mechanical ventilation and intensive care unit stay. Serum CC16 levels on POD1 increased significantly from the pretransplant state in the ARDS group but not in the non-ARDS group. Pretransplant serum CC16 levels were also higher in the ARDS group. The area under the receiver operating characteristic curves for POD1 serum CC16 levels used to discriminate ARDS was 0.803 (95% confidence interval: 0.679 to 0.895; p < 0.001). By comparison, HMGB1, IL-1β, and IL-10 were not associated with ARDS after LDLT.

Conclusion

The higher pretransplant serum CC16 level and its increased level on POD1 were associated with the development of early ARDS after LDLT. This trial is registered with NCT01936545, 27 August 2013.

[rotective effect of bone marrow mesenchymal stem cells-derived exosomes against testicular ischemia-reperfusion injury in rats]

OBJECTIVE

To investigate the protective effect of bone marrow mesenchymal stem cells (BMSCs)-derived exosomesagainst testicular ischemia-reperfusion injury (IRI) in rats.

METHODS

Rat BMSCs were isolated, cultured and identified in theprimary culture. The exosomes were extracted from the BMSCs and characterized using nanoparticle tracking analysis, transmission electron microscopy, and Western blotting. Twenty-four healthy male SD rats were randomly divided into shamoperation group, testicular IRI with saline treatment group and IRI with exosome treatment group. The contralateral testes ofthe rats were collected for pathological observation, aseessment of superoxide dismutase (SOD) and malondialdehyde (MDA), and detection of HMGB1, caspases-3 and cleaved caspase-3 expressions using Western blotting.

RESULTS

We successfullyobtained exosomes from rat BMSCs. Testicular IRI significantly impaired testicular spermatogenesis, which was markedlyimproved by treatment with the exosomes (P < 0.05). Testicular IRI also caused significant increase in the protein expression ofHMGB1, caspase-3 and cleaved caspase-3 in the testicular tissue, and treatment with the exosomes obviously amelioratedthese changes (P < 0.05).

CONCLUSIONS

BMSCs-derived exosomes protects against testicular IRI due to the anti-oxidant, antiinflammatory and anti-apoptosis activities of the exosomes.

Dual Effect of Hepatic Macrophages on Liver Ischemia and Reperfusion Injury during Liver Transplantation

Ischemia-reperfusion injury (IRI) is a major complication in liver transplantation (LT) and it is closely related to the recovery of grafts' function. Researches has verified that both innate and adaptive immune system are involved in the development of IRI and Kupffer cell (KC), the resident macrophages in the liver, play a pivotal role both in triggering and sustaining the sterile inflammation. Damage-associated molecular patterns (DAMPs), released by the initial dead cell because of the ischemia insult, firstly activate the KC through pattern recognition receptors (PRRs) such as toll-like receptors. Activated KCs is the dominant players in the IRI as it can secret various pro-inflammatory cytokines to exacerbate the injury and recruit other types of immune cells from the circulation. On the other hand, KCs can also serve in a contrary way to ameliorate IRI by upregulating the anti-inflammatory factors. Moreover, new standpoint has been put forward that KCs and macrophages from the circulation may function in different way to influence the inflammation. Managements towards KCs are expected to be the effective way to improve the IRI.

Hydrogen-Rich Saline Ameliorates Hepatic Ischemia-Reperfusion Injury Through Regulation of Endoplasmic Reticulum Stress and Apoptosis

OBJECTIVE

To evaluate the effect of hydrogen-rich saline (HS) on hepatic ischemia-reperfusion (I/R) injury.

METHODS

Forty rats were randomly allocated into five groups: one sham group (control group), one group treated with 20 min of ischemia and normal saline (NS; I/R1 + NS group), one group treated with 20 min of ischemia and HS (I/R1 + HS group), one group treated with 60 min of ischemia and NS (I/R2 + NS group), and one group treated with 60 min of ischemia and HS (I/R2 + HS group). After reperfusion for 6 h, hepatic function, oxidative stress, pathological changes, and apoptosis of hepatic cells were evaluated. Furthermore, the expression levels of endoplasmic reticulum (ER) stress-associated proteins were identified.

RESULTS

Serum ALT and AST levels and tissue MDA content in the I/R + HS groups were significantly lower than those in the I/R + NS groups. Pathological changes were also significantly ameliorated in the HS groups compared with those in the NS groups. Moreover, HS appeared to significantly attenuate hepatic I/R-induced ER stress responses, as indicated by the decreased expression of C/EBP homologous protein, protein-kinase-RNA-like ER kinase, and inositol-requiring protein-1α, as well as the increased expression of GRP78 proteins. Finally, the levels of apoptotic markers such as caspase-3 and TUNEL-positive cells were significantly lower in the HS groups than in the NS control groups, whereas the level of Bcl2 protein increased in the HS groups.

CONCLUSION

The protective effect of HS can be attributed to ER stress and apoptosis inhibition.

Elevated microRNA-129-5p level ameliorates neuroinflammation and blood-spinal cord barrier damage after ischemia-reperfusion by inhibiting HMGB1 and the TLR3-cytokine pathway

Background

Ischemia-reperfusion (IR) affects microRNA (miR) expression and causes substantial inflammation. Multiple roles of the tumor suppressor miR-129-5p in cerebral IR have recently been reported, but its functions in the spinal cord are unclear. Here, we investigated the role of miR-129-5p after spinal cord IR, particularly in regulating high-mobility group box-1 (HMGB1) and the Toll-like receptor (TLR)-3 pathway.

Methods

Ischemia was induced via 5-min occlusion of the aortic arch. The relationship between miR-129-5p and HMGB1 was elucidated via RT-PCR, western blotting, and luciferase assays. The cellular distribution of HMGB1 was determined via double immunofluorescence. The effect of miR-129-5p on the expression of HMGB1, TLR3, and downstream cytokines was evaluated using synthetic miRs, rHMGB1, and the TLR3 agonist Poly(I:C). Blood-spinal cord barrier (BSCB) permeability was examined by measuring Evans blue (EB) dye extravasation and the water content.

Results

The temporal miR-129-5p and HMGB1 expression profiles and luciferase assay results indicated that miR-129-5p targeted HMGB1. Compared with the Sham group, the IR group had higher HMGB1 immunoreactivity, which was primarily distributed in neurons and microglia. Intrathecal injection of the miR-129-5p mimic significantly decreased the HMGB1, TLR3, interleukin (IL)-1β and tumor necrosis factor (TNF)-α levels and the double-labeled cell count 48 h post-surgery, whereas rHMGB1 and Poly(I:C) reversed these effects. Injection of miR-129-5p mimic preserved motor function and prevented BSCB leakage based on increased Basso Mouse Scale scores and decreased EB extravasation and water content, whereas injection rHMGB1 and Poly(I:C) aggravated these injuries.

Conclusions

Increasing miR-129-5p levels protect against IR by ameliorating inflammation-induced neuronal and BCSB damage by inhibiting HMGB1 and TLR3-associated cytokines.