Liver Ischemia-reperfusion Injury Research Articles

Melatonin attenuates liver ischemia-reperfusion injury via inhibiting the PGAM5-mPTP pathway

Phosphoglycerate mutase/protein phosphatase (PGAM5)-mediated cell death plays an important role in multiple liver diseases. However, few studies have confirmed the regulatory mechanism of melatonin acting on PGAM5-mediated cell death in the context of liver ischemia-reperfusion (I/R) injury. The liver I/R injury model and cell hypoxia-reoxygenation model were established after melatonin pretreatment. Liver injury, cell activity, cell apoptosis, oxidative stress index, and PGAM5 protein expression were detected. To investigate the role of PGAM5 in melatonin-mediated liver protection during I/R injury, PGAM5 silencing, and overexpression were performed before melatonin pretreatment. Our results indicated that PGAM5 was significantly elevated by I/R injury, and predominantly localized in the necrosis area. However, treatment with melatonin blocked PGAM5 activation and conferred a survival advantage of hepatocytes in liver I/R injury, similar to the results achieved by silencing PGAM5. In terms of mechanism, we illustrated that activated PGAM5 promoted mitochondrial permeability transition pore (mPTP) opening, and administration of melatonin inhibited mPTP opening and interrupted hepatocytes death via blocking PGAM5. Our data indicated that the PGAM5-mPTP axis is responsible for I/R-induced liver injury. In contrast, melatonin supplementation blocked the PGAM5-mPTP axis and thus decreased cell death, providing a protective advantage to hepatocytes in I/R. These results established a new paradigm in melatonin-mediated hepatocyte protection under the burden of I/R attack.

Targeting S100A9-TLR2 axis controls macrophage NLRP3 inflammasome activation in fatty liver ischemia reperfusion injury

Abstract Liver ischemia reperfusion (IR) injury significantly impacts clinical outcomes by increasing the risk of hepatic dysfunction after liver surgery. Fatty livers are more susceptible to IR stress. Recent studies have demonstrated that S100A9 plays a crucial role in both IR injury and the progression of liver steatosis. Nevertheless, the precise mechanisms underlying these effects remain unclear. In our study, transcriptome analysis of fatty livers subjected to IR insult in mice identified S100A9 as an important mediator. Employing loss-of-function approaches, we investigated the immune regulatory function of S100A9 and its downstream signaling in fatty liver IR injury. As expected, S100A9 emerged as one of the most significantly upregulated genes during the reperfusion stage in fatty livers. Genetic knockdown of S100A9 markedly ameliorated liver pathological damage, evidenced by reduced macrophage/neutrophil infiltration as well as the decreased expression of proinflammatory factors. Transcriptome/functional studies revealed that S100A9 triggered liver inflammatory response via regulating Toll-like receptor 2 (TLR2)/Activating transcription factor 4 (ATF4) signaling. Additionally, TLR2 expression was notably increased in macrophages from ischemic fatty livers. In vitro, recombinant S100A9-stimulated macrophages exhibited the elevated production of proinflammatory factors and TLR2/ATF4 pathway activation. Intriguingly, S100A9 facilitated ATF4 nuclear translocation and enhanced NEK7/NLRP3 inflammasome activation in macrophages. In conclusion, our study identified S100A9 as a key regulator responsible for macrophage NLRP3 inflammasome activation and subsequent inflammatory injury in fatty liver IR process. Targeting TLR2/ATF4 signaling may offer a novel therapeutic strategy for mitigating S100A9-mediated liver injury.

Phosphatidylserine-mediated uptake of extracellular vesicles by hepatocytes ameliorates liver ischemia-reperfusion injury.

Compelling evidence suggests that mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) promote regeneration in animal models of liver injury by delivering signaling molecules. However, their target cells and uptake mechanism remain elusive. In this study, MSC-EVs were intravenously administered in a mouse model of liver ischemia-reperfusion injury (IRI). Our results revealed that MSC-EVs exhibit enhanced liver targeting in IRI mice, and injured hepatocytes display a greater capacity for MSC-EV uptake. We found that phosphatidylserine (PS) displayed on the exterior of injured hepatocytes promotes MSC-EV internalization, possibly by binding to MFGE8, a protein expressed on the MSC-EV membrane. Furthermore, the therapeutic effect of MSC-EVs on liver IRI is highly dependent on this PS-mediated uptake pathway. Our findings provide evidence that MSC-EVs preferentially target injured hepatocytes, relying on a PS-dependent uptake route to exert hepatoprotective effects, which are critical for the future design of EV-based therapeutic strategies for liver IRI.

S100A9 regulates M1 macrophage polarization and exacerbates steatotic liver ischemia-reperfusion injury

ObjectiveSteatotic livers exhibit higher susceptibility to ischemia reperfusion (IR) injury, which increase the risk of primary graft non-function following liver transplantation. S100A9 is identified as a pivotal innate immune sensor that regulates the progression of liver diseases. However, its significance in steatotic liver IR injury remains under-investigated. MethodsIn mice model, we generated S100A9 knockout (S100A9 KO) mice to investigate the role of S100A9 in IR-stimulated steatotic livers. In vitro, primary bone marrow-derived macrophages were utilized to explore the effect of S100A9 in regulating macrophage polarization and inflammation. ResultsS100A9 expression was markedly increased in steatotic livers of mice subjected to IR insult. S100A9 deletion significantly attenuated liver inflammatory injury, as evidenced by the diminished infiltration of both monocytes/macrophages and neutrophils (p < 0.05). The expression of proinflammatory factors was reduced (p < 0.05) at the same time. Additionally, S100A9-deficient livers demonstrated M1 polarization decrease and Toll-like receptor 4 (TLR4) suppression (p < 0.05). In vitro, genetic TLR4 inhibition led to nuclear factor kappa B (NF-κB) inactivation and subsequent M1 polarization decrease (p < 0.05) in macrophages treated with recombinant S100A9. ConclusionIn this study, we highlight the pivotal role of TLR4/NF-κB as a critical mediator of S100A9 in inducing M1 macrophage polorization- dependent inflammation in steatotic livers IR injury.

Gut-Liver Axis: Modulating the Gut Microbiota and Its Metabolic Products as a Potential Therapeutic Strategy for the Treatment of Hepatic Ischemia-Reperfusion Injury.

Hepatic ischemia-reperfusion injury (HIRI) is a major complication reported in various clinical scenarios such as liver transplantation (LTx), hepatectomy, and acute hepatic insult. This condition affects the restoration of hepatic functionalities post-LTx. Contemporary scientific inquiries have highlighted the involvement of intestinal microbiota and their metabolic by-products in the initiation and progression of HIRI. Perturbations in the gut microbiome, instigated by external stressors such as inflammatory processes, ischemic conditions, and reperfusion events, affect the biosynthesis of metabolites such as short-chain fatty acids (SCFAs), bile acids (BAs), and lipopolysaccharides (LPS). SCFAs can exert anti-inflammatory effects, modulate cellular apoptosis, and attenuate oxidative stress, thereby ameliorating hepatic injury. Other studies have shown that the intestinal microbiota confers hepatoprotective effects by modulating the host's immune response and synthesis of cytokines, controlling inflammation, and enhancing liver protection. This review comprehensively describes the mechanisms underlying the association of gut microbiota and its metabolites with hepatic disease and ischemia-reperfusion injury. The findings from recent studies investigating the gut-liver axis are reviewed to identify therapeutic avenues for the prevention and treatment of liver dysfunction and ischemia-reperfusion injury. In-so-doing, novel pathways and perspectives can be exploited to develop therapies for the control of inflammatory hepatic ischemia-reperfusion injury, particularly following liver transplantation or surgical intervention.

Redox-sensitive epigenetic activation of SUV39H1 contributes to liver ischemia-reperfusion injury

Liver ischemia-reperfusion (I/R) injury is a clinically relevant pathophysiological process that determines the effectiveness of life-saving liver transplantation, to which aberrant ROS accumulation plays a key role. In the present study we investigated the role of SUV39H1, a lysine methyltransferases, in this process focusing on regulatory mechanism and translational potential. We report that SUV39H1 expression was up-regulated in the liver tissues of mice subjected to ischemia-reperfusion and in hepatocytes exposed to hypoxia-reoxygenation (H/R) in a redox-sensitive manner. Mechanistically, coactivator associated arginine methyltransferases 1 (CARM1) mediated redox-sensitive Suv39h1 trans-activation by promoting histone H3R17 methylation. Consistently, pharmaceutical CARM1 inhibition attenuated liver I/R injury. In addition, global or hepatocyte conditional Suv39h1 KO mice were protected from liver I/R injury. RNA-seq revealed that aldehyde dehydrogenase 1 family 1a (Aldh1a1) as a novel target for SUV39H1. SUV39H1 directly bound to the Aldh1a1 promoter and repressed Aldh1a1 transcription in H/R-challenged hepatocytes. ALDH1A1 silencing abrogated the protective effects of SUV39H1 deficiency on H/R-inflicted injuries whereas ALDH1A1 over-expression mitigated liver I/R injury in mice. Importantly, administration of a small-molecule SUV39H1 inhibitor achieved similar hepatoprotective effects as SUV39H1 deletion. Finally, increased Suv39h1 expression and decreased Aldh1a1 expression were observed in liver I/R specimens in humans. In conclusion, our data uncover a regulatory role for SUV39H1 in liver I/R injury and serve as proof-of-concept that targeting the SUV39H1- ALDH1A1 axis might be considered as a reasonable approach for the intervention of liver I/R injury.

High Intensity Aerobicexercise Preconditioning Decreases Oxidative Stress Damage Associated With Rat Liver Ischemia-reperfusion Injury

High Intensity Aerobicexercise Preconditioning Decreases Oxidative Stress Damage Associated With Rat Liver Ischemia-reperfusion Injury

Sedentary Lifestyle Worsens Liver Ischemia-Reperfusion Injury Via Inflammation Mediated By Myeloperoxidase In Animal Model

Sedentary Lifestyle Worsens Liver Ischemia-Reperfusion Injury Via Inflammation Mediated By Myeloperoxidase In Animal Model

Differential Effects of HDAC6 Inhibition Versus Knockout During Hepatic Ischemia-Reperfusion Injury Highlight Importance of HDAC6 C-terminal Zinc-finger Ubiquitin-binding Domain.

Ischemia-reperfusion injury (IRI) causes significant morbidity in liver transplantation among other medical conditions. IRI following liver transplantation contributes to poor outcomes and early graft loss. Histone/protein deacetylases (HDACs) regulate diverse cellular processes, play a role in mediating tissue responses to IRI, and may represent a novel therapeutic target in preventing IRI in liver transplantation. Using a previously described standardized model of murine liver warm IRI, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were assessed at 24 and 48 h after reperfusion to determine the effect of different HDAC inhibitors. Broad HDAC inhibition with trichostatin-A (TSA) was protective against hepatocellular damage ( P < 0.01 for AST and P < 0.05 for ALT). Although HDAC class I inhibition with MS-275 provided statistically insignificant benefit, tubastatin-A (TubA), an HDAC6 inhibitor with additional activity against HDAC10, provided significant protection against liver IRI ( P < 0.01 for AST and P < 0.001 for ALT). Surprisingly genetic deletion of HDAC6 or -10 did not replicate the protective effects of HDAC6 inhibition with TubA, whereas treatment with an HDAC6 BUZ-domain inhibitor, LakZnFD, eliminated the protective effect of TubA treatment in liver ischemia ( P < 0.01 for AST and P < 0.01 for ALT). Our findings suggest TubA, a class IIb HDAC inhibitor, can mitigate hepatic IRI in a manner distinct from previously described class I HDAC inhibition and requires the HDAC6 BUZ-domain activity. Our data corroborate previous findings that HDAC targets for therapeutic intervention of IRI may be tissue-specific, and identify HDAC6 inhibition as a possible target in the treatment of liver IRI.

Ferroptosis Inhibition: A Key Opportunity for the Treatment of Ischemia/Reperfusion Injury in Liver Transplantation.

The outcome after liver transplantation has improved in recent years, which can be attributed to superior storage and transportation conditions of the organs, as well as better peri- and postoperative management and advancements in surgical techniques. Nevertheless, there is an increasing discrepancy between the need for organs and their availability. Consequently, the mortality rate on the waiting list is high and continues to rise. One way of counteracting this trend is to increase the use of "expanded criteria donors." This means that more and more donors will be included, especially those who are older and having additional comorbidities (eg, steatosis). A major complication of any transplantation is the occurrence of ischemia/reperfusion injury (IRI), which often leads to liver dysfunction and failure. However, there have been various promising approaches to minimize IRI in recent years, but an effective and clinically applicable method to achieve a better outcome for patients after liver transplantation is still missing. Thereby, the so-called marginal organs are predominantly affected by IRI; thus, it is crucial to develop suitable and effective treatment options for patients. Recently, regulated cell death mechanisms, particularly ferroptosis, have been implicated to play a major role in IRI, including the liver. Therefore, inhibiting this kind of cell death modality presents a promising therapeutic approach for the management of this yet untreatable condition. Thus, this review provides an overview of the role of ferroptosis in liver IRI and transplantation and discusses possible therapeutic solutions based on ferroptosis inhibition to restrain IRI in marginal organs (especially steatosis and donation after circulatory death organs).

Perfusate hemoglobin during normothermic liver machine perfusion as biomarker of early allograft dysfunction: Apilot study.

Normothermic machine perfusion (NMP) aims to reduce ischemia-reperfusion injury in donor livers and its clinical manifestation, early allograft dysfunction (EAD) by maintaining perfusion and oxygenation. However, there is limited data on which NMP perfusate biomarkers might be associated with such EAD and the role of perfusate hemoglobin has not been assessed. We performed a pilot retrospective analysis of adult donor livers undergoing NMP between 2020 and 2022 at our center. NMP was commenced at the recipient hospital after initial static cold storage. All NMP circuits were primed in the same manner according to the manufacturer's instructions. Livers were stratified by initial perfusate hemoglobin below (≤5.2 mmol/L) or above (>5.2 mmol/L) the median. The association between hemoglobin levels and EAD or recipient peak transaminase levels was assessed. Among 23 livers, eight were considered unsuitable for transplantation, leaving 15 livers for assessment. Higher initial hemoglobin was associated with a lower risk of EAD (0% vs. 55.6%, p = 0.04). Perfusate hemoglobin decreased after NMP initiation (p = 0.003) and negatively correlated with recipient peak transaminase levels (ALT: ρ = -0.72, p = 0.002; AST: ρ = -0.79, p < 0.001). Consistently, higher hemoglobin livers also demonstrated lower perfusate liver enzymes. Perfusate hemoglobin levels decreased during NMP, and lower perfusate hemoglobin levels were associated with a higher incidence of EAD and higher levels of liver injury markers. Maintaining higher hemoglobin levels during NMP may help reduce ischemia-reperfusion injury and prevent or attenuate EAD. Larger prospective studies are needed to validate the findings of this pilot study.

CTGF regulated by ATF6 inhibits vascular endothelial inflammation and reduces hepatic ischemia–reperfusion injury

Vascular endothelial inflammation is crucial in hepatic ischemia–reperfusion injury (IRI). Our previous research has shown that connective tissue growth factor (CTGF), secreted by endothelial cells, protects against acute liver injury, but its upstream mechanism is unclear. We aimed to clarify the protective role of CTGF in endothelial cell inflammation during IRI and reveal the regulation between endoplasmic reticulum stress-induced activating transcription factor 6 (ATF6) and CTGF. Hypoxia/reoxygenation in endothelial cells, hepatic IRI in mice and clinical specimens were used to examine the relationships between CTGF and inflammatory factors and determine how ATF6 regulates CTGF and reduces damage. We found that activating ATF6 promoted CTGF expression and reduced liver damage in hepatic IRI. In vitro, activated ATF6 upregulated CTGF and downregulated inflammation, while ATF6 inhibition had the opposite effect. Dual-luciferase assays and chromatin immunoprecipitation confirmed that activated ATF6 binds to the CTGF promoter, enhancing its expression. Activated ATF6 increases CTGF and reduces extracellular regulated protein kinase 1/2 (ERK1/2) phosphorylation, decreasing inflammatory factors. Conversely, inhibiting ATF6 decreases CTGF and increases the phosphorylation of ERK1/2, increasing inflammatory factor levels. ERK1/2 inhibition reverses this effect. Clinical samples have shown that CTGF increases after IRI, inversely correlating with inflammatory cytokines. Therefore, ATF6 activation during liver IRI enhances CTGF expression and reduces endothelial inflammation via ERK1/2 inhibition, providing a novel target for diagnosing and treating liver IRI.

JuA alleviates liver ischemia-reperfusion injury by activating AKT/NRF2/HO-1 pathways

Liver ischemia-reperfusion (I/R) injury is a detrimental complication of organ transplantation, shock, and sepsis. However, the available drugs to mitigate I/R injury remain limited. Jujuboside A (JuA) is renowned for its antioxidant, anti-inflammatory, and anti-apoptotic properties; nevertheless, its potential in liver I/R injury remains unknown. Thus, this study aimed to explore the role and underlying mechanisms of JuA in liver I/R injury. Mouse models of I/R and AML12 cell models of hypoxia/reoxygenation (H/R) were constructed. Haematoxylin and eosin staining, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) detection, and cell viability analysis were used to assess liver injury. To evaluate oxidative stress, inflammation, apoptosis, and mitochondrial damage, immunofluorescence staining, transmission electron microscopy analysis, enzyme-linked immunosorbent assay, and flow cytometry were conducted. Moreover, molecular docking techniques and western blot were employed to identify downstream target molecules and pathways affected by JuA. The results showed that JuA pretreatment effectively attenuated liver necrosis and ALT and AST level elevations induced by I/R while enhancing AML12 cell viability following H/R. Furthermore, JuA pretreatment suppressed oxidative stress triggered by I/R and H/R, thereby inhibiting the level of pro-inflammatory factors and NLRP3 inflammasome activation. Notably, JuA pretreatment alleviated mitochondrial damage and apoptosis. Mechanistically, JuA pretreatment resulted in the activation of the AKT/NRF2/HO-1 signalling pathways, whereas MK2206, the inhibitor of AKT, partially reversed the hepatoprotective effects of JuA during liver I/R. Collectively, our findings illustrated that JuA mitigated oxidative stress, inflammation, apoptosis, and mitochondrial damage by facilitating the AKT/NRF2/HO-1 signalling pathway, thereby alleviating liver I/R injury.

XBP1 Facilitating NF-κB-p65 Nuclear Translocation Promotes Macrophage-Originated Sterile Inflammation Via Regulating MT2 Transcription in the Ischemia/Reperfusion Liver

Background & AimsXBP1, most conserved transcription factor of endoplasmic reticulum (ER) stress, plays important roles in physiological and pathological settings and has profound effects on disease progression and prognosis, so it’s necessary to investigate XBP1 in macrophage-originated sterile inflammation during liver ischemia/reperfusion injury (IRI). Macrophage XBP1 expression and liver injury are analyzed in patients undergoing ischemia-related hepatectomy. MethodsA myeloid-specific male XBP1-knockout (XBP1M-KO) strain is created for function and mechanism of XBP1 on macrophage-derived sterile inflammation in murine liver IRI with in-vitro parallel research. Macrophages co-cultured with hypoxia-treated hepatocytes are applied to investigate impact of XBP1 in vitro, with analysis of RNA sequencing and databases. ResultsClinically, macrophage XBP1 expression significantly increases in ischemic liver tissues and positively correlates with liver injury after hepatectomy. Less hepatocellular damage is presented in XBP1M-KO mice than in XBP1-proficient (XBP1FL/FL) controls. In vitro, XBP1 deficiency inhibits sterile inflammation and migration in macrophages co-cultured with hypoxia-treated hepatocytes. Analysis of RNA sequencing and databases determines Metallothionein 2 (MT2) as XBP1 target gene, negatively regulated by binding with its promoter. XBP1 deficiency increases MT2 and IKBα expression, but inhibits NF-κB-p65 phosphorylation, markedly neutralizing XBP1M-KO-related benefits by promoting sterile inflammation during liver IRI. ConclusionsXBP1 promotes macrophage-originated sterile inflammation, increases liver IRI by binding to MT2 promoter, and regulates MT2/NF-κB pathway, potentially therapeutic for clinical liver IRI.

Leukocyte cell-derived chemotaxin 2 (LECT2) regulates liver ischemia–reperfusion injury

Background and aimHepatic ischemia–reperfusion injury (IRI) is a significant challenge in liver transplantation, trauma, hypovolemic shock, and hepatectomy, with limited effective interventions available. This study aimed to investigate the role of leukocyte cell-derived chemotaxin 2 (LECT2) in hepatic IRI and assess the therapeutic potential of Lect2-short hairpin RNA (shRNA) delivered through adeno-associated virus (AAV) vectors. Materials and methodsThis study analyzed human liver and serum samples from five patients undergoing the Pringle maneuver. Lect2-knockout and C57BL/6J mice were used. Hepatic IRI was induced by clamping the hepatic pedicle. Treatments included recombinant human LECT2 (rLECT2) and AAV-Lect2-shRNA. LECT2 expression levels and serum biomarkers including alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, and blood urea nitrogen (BUN) were measured. Histological analysis of liver necrosis and quantitative reverse-transcription polymerase chain reaction were performed. ResultsSerum and liver LECT2 levels were elevated during hepatic IRI. Serum LECT2 protein and mRNA levels increased post reperfusion. Lect2-knockout mice had reduced weight loss; hepatic necrosis; and serum ALT, AST, creatinine, and BUN levels. rLECT2 treatment exacerbated weight loss, hepatic necrosis, and serum biomarkers (ALT, AST, creatinine, and BUN). AAV-Lect2-shRNA treatment significantly reduced weight loss, hepatic necrosis, and serum biomarkers (ALT, AST, creatinine, and BUN), indicating therapeutic potential. ConclusionsElevated LECT2 levels during hepatic IRI increased liver damage. Genetic knockout or shRNA-mediated knockdown of Lect2 reduced liver damage, indicating its therapeutic potential. AAV-mediated Lect2-shRNA delivery mitigated hepatic IRI, offering a potential new treatment strategy to enhance clinical outcomes for patients undergoing liver-related surgeries or trauma.

264.4: Macrophage SETDB1 reduces inflammatory macrophage infiltration by inhibiting P2rx7 expression and alleviates liver ischemia-reperfusion injury.

264.4: Macrophage SETDB1 reduces inflammatory macrophage infiltration by inhibiting P2rx7 expression and alleviates liver ischemia-reperfusion injury.

ZLN005, a PGC-1α Activator, Protects the Liver against Ischemia-Reperfusion Injury and the Progression of Hepatic Metastases.

Exercise can promote sustainable protection against cold and warm liver ischemia-reperfusion injury (IRI) and tumor metastases. We have shown that this protection is by the induction of hepatic mitochondrial biogenesis pathway. In this study, we hypothesize that ZLN005, a PGC-1α activator, can be utilized as an alternative therapeutic strategy. Eight-week-old mice were pretreated with ZLN005 and subjected to liver warm IRI. To establish a liver metastatic model, MC38 cancer cells (1 × 106) were injected into the spleen, followed by splenectomy and liver IRI. ZLN005-pretreated mice showed a significant decrease in IRI-induced tissue injury as measured by serum ALT/AST/LDH levels and tissue necrosis. ZLN005 pretreatment decreased ROS generation and cell apoptosis at the site of injury, with a significant decrease in serum pro-inflammatory cytokines, innate immune cells infiltration, and intrahepatic neutrophil extracellular trap (NET) formation. Moreover, mitochondrial mass was significantly upregulated in hepatocytes and maintained after IRI. This was confirmed in murine and human hepatocytes treated with ZLN005 in vitro under normoxic and hypoxic conditions. Additionally, ZLN005 preconditioning significantly attenuated tumor burden and increased the percentage of intratumoral cytotoxic T cells. Our study highlights the effective protection of ZLN005 pretreatment as a therapeutic alternative in terms of acute liver injury and tumor metastases.

Mitigating Cold Ischemic Injury: HTK, UW and IGL-2 Solution's Role in Enhancing Antioxidant Defence and Reducing Inflammation in Steatotic Livers.

Liver transplantation remains the only definitive treatment for end-stage liver diseases. However, the increasing prevalence of fatty liver disease among potential donors exacerbates the shortage of suitable organs. This study evaluates the efficacy of the preservation solution Institut Georges Lopez-2 (IGL-2) compared to Histidine-Tryptophan-Ketoglutarate (HTK) and University of Wisconsin (UW) preservation solutions in mitigating ischemia-reperfusion injury (IRI) in steatotic livers. Using Zucker Obese rat livers, we assessed the impact of 24-h static cold storage (SCS) with each solution on transaminase release, glutathione redox balance, antioxidant enzyme activity, lipoperoxidation, and inflammation markers. IGL-2 and UW solutions demonstrated reduced transaminase and lactate levels compared to HTK, indicating better preservation of liver integrity. IGL-2 maintained a higher reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, suggesting more effective management of oxidative stress. Antioxidant enzyme activities catalase, superoxide dismutase, and glutathione peroxidase (CAT, SOD, GPX) were higher in IGL-2 preserved livers, contributing to decreased oxidative damage. Lipid peroxidation markers and inflammatory markers were lower in IGL-2 than in HTK, indicating reduced oxidative stress and inflammation. Additionally, improved mitochondrial function was observed in the IGL-2 group, correlating with reduced reactive oxygen species (ROS) production and lipid peroxidation. These findings suggest that IGL-2 offers superior preservation of liver viability, reduces oxidative stress, and minimizes inflammation compared to HTK and UW solutions. By maintaining a higher ratio of reduced glutathione and antioxidant enzyme activity, IGL-2 effectively mitigates the harmful effects of ischemia-reperfusion injury. The reduced lipid peroxidation and inflammation in the IGL-2 group further underscore its potential in improving liver transplant outcomes. These results highlight the importance of optimizing preservation solutions to enhance the viability and functionality of donor organs, potentially expanding the donor pool and improving the success rates of liver transplantation. Future research should focus on refining preservation techniques and exploring additional protective agents to further improve organ preservation and transplant outcomes.

Hypothermic oxygenated machine perfusion influences the immunogenicity of donor livers in humans.

Hypothermic oxygenated machine perfusion (HOPE) is an organ preservation strategy shown to reduce ischemia-reperfusion-injury (IRI)-related complications following liver transplantation (LT). In animal models HOPE can also decrease alloimmune responses post-transplantation, but this remains to be evaluated in humans. Our study, involving 27 LT patients enrolled in 2 randomised controlled trials comparing static cold storage (SCS) with HOPE (14 HOPE- and 13 SCS-treated), delves into the impact of HOPE on the molecular profile of liver allografts and on the immune responses elicited post-transplantation. Following HOPE treatment, fewer intra-hepatic immune cells were observed in liver perfusates compared to SCS. Analysis of liver tissue transcriptome at reperfusion revealed an effect of HOPE on the reactive oxygen species pathway. Two weeks post-transplantation, HOPE recipients exhibited increased circulating CD4+FOXP3+CD127lo regulatory T cells (Tregs) (p<0.01), which corresponded to a higher frequency of donor specific Tregs (p<0.01) and was followed by reduced alloreactivity index of CD8+ T cells 3 months post-transplant. Our study provides novel mechanistic insight into the capacity of HOPE to influence liver IRI and to modulate effector and regulatory donor-specific T cell responses post-transplantation. These findings, which confirm observations made in animal models, help explain the decreased rejection rates reported in patients receiving HOPE-treated allografts.

Reversible Fluorescent Probes for Dynamic Imaging of Liver Ischemia-Reperfusion Injury.

ConspectusHepatic ischemia-reperfusion injury (HIRI) is an inevitable complication of clinical surgeries such as liver resection or transplantation, often resulting in postoperative liver dysfunction, hepatic failure in up to 13% of postresection patients, and early graft failure in 11-18% of liver transplantation patients. HIRI involves a series of biochemical events triggered by abnormal alterations in multiple biomarkers, characterized by short lifespans, dynamic changes, subcellular regional distribution, and multicollaborative regulation. However, traditional diagnosis, including serology, imaging, and liver puncture biopsy, suffers from low sensitivity, poor resolution, and hysteresis, which hinder effective monitoring of HIRI markers. Thus, to address the unique properties of HIRI markers, there is a pressing demand for developing novel detection strategies that are highly selective, transiently responsive, dynamically reversible, subcellular organelle-targeted, and capable of simultaneous multicomponent analysis.Optical probe-based fluorescence imaging is a powerful tool for real-time monitoring of biomarkers with the advantages of high sensitivity, noninvasiveness, rapid analysis, and high-fidelity acquisition of spatiotemporal information on signaling molecules compared with conventional methods. Moreover, with the growing demand for continuous monitoring of biomarkers, probes with reversible detection features are receiving more and more attention. Importantly, reversible probes can not only monitor fluctuations in marker concentrations but also distinguish between transient bursts of markers during physiological events and long-term sustained increases in pathological marker levels. This can effectively avoid false-positive test results, and in addition, reversible probes can be reutilized with green and economical features. Therefore, our team has employed various effective methods to design reversible optical probes for HIRI. We proposed reversible recognition strategies based on specific reactions or interactions to detect dynamic changes in markers. Given the biomarkers' unique signaling in subcellular organelles and the synergistic regulatory properties of multiple markers for HIRI, bifunctional reversible detection strategies are exploited, including organelle-targeted reversible and multicomponent simultaneous detection. With these strategies, we have tailored a variety of high-fidelity fluorescent probes for a series of HIRI markers, including reactive oxygen/nitrogen species (O2•- and ONOO-), ATP, protein (Keap1), mitochondrial DNA, etc. Utilizing the probes, the in situ dynamic imaging detection of the HIRI markers was successfully achieved. While performing the precise examination of the earlier occurrence of HIRI disease and visualizing the real-time monitoring of the disease process, we have also further elucidated the HIRI-associated signaling pathways. It is envisioned that our summarized work will inspire the design of future reversible fluorescent probes and help to improve the clinical diagnosis and therapeutic efficiency of these diseases.