Liver ischaemia-reperfusion injury: a new understanding of the role of innate immunity

Ticlopidine protects hepatic ischemia-reperfusion injury via suppressing ferroptosis

Hepatic ischemia-reperfusion injury (IRI) is a major cause of liver damage during hepatic resection, transplantation, and other surgical procedures, often leading to graft failure and liver dysfunction. Recent studies have identified ferroptosis, a form of regulated cell death characterized by iron-dependent lipid peroxidation, as a key contributor to IRI. In this study, we investigated the protective effects of Ticlopidine, a thienopyridine compound and platelet aggregation inhibitor, on hepatic IRI. Using a C57BL/6J mouse model, we demonstrated that prophylactic Ticlopidine treatment significantly reduced necrotic and fibrotic areas in liver tissues, as well as serum levels of alanine transaminase (ALT) and aspartate aminotransferase (AST). Prussian Blue staining revealed that Ticlopidine pretreatment decreased iron accumulation in hepatic tissues, whereas markers of lipid peroxidation (malondialdehyde and 4-hydroxynonenal) and ferroptosis (PTGS2) were significantly downregulated. Additionally, Ticlopidine ameliorated inflammatory infiltration as indicated by reduced Gr-1 staining. In vitro, Ticlopidine dose-dependently inhibited ferroptosis induced by various inducers in liver cancer cell lines HUH7 and fibrosarcoma cells HT1080. The protective effects involved partial rescue of lipid peroxidation, significant reduction of ferrous iron levels, and strong protection against mitochondrial damage. These findings suggested that Ticlopidine acts as a broad-spectrum ferroptosis inhibitor, offering a promising therapeutic approach for protecting the liver against IRI.

FGF21 modulates immunometabolic homeostasis via the ALOX15/15-HETE axis in early liver graft injury

Fibroblast growth factor 21 (FGF21) is essential for modulating hepatic homeostasis, but the impact of FGF21 on liver graft injury remains uncertain. Here, we show that high FGF21 levels in liver graft and serum are associated with improved graft function and survival in liver transplantation (LT) recipients. FGF21 deficiency aggravates early graft injury and activates arachidonic acid metabolism and regional inflammation in male mouse models of hepatic ischemia/reperfusion (I/R) injury and orthotopic LT. Mechanistically, FGF21 deficiency results in abnormal activation of the arachidonate 15-lipoxygenase (ALOX15)/15-hydroxy eicosatetraenoic acid (15-HETE) pathway, which triggers a cascade of innate immunity-dominated pro-inflammatory responses in grafts. Notably, the modulating role of FGF21/ALOX15/15-HETE pathway is more significant in steatotic livers. In contrast, pharmacological administration of recombinant FGF21 effectively protects against hepatic I/R injury. Overall, our study reveals the regulatory mechanism of FGF21 and offers insights into its potential clinical application in early liver graft injury after LT.

Factors affecting neutrophil functions during sepsis: human microbiome and epigenetics

Sepsis is a severe disease that occurs when the body's immune system reacts excessively to infection. The body's response, which includes an intense antibacterial reaction, can damage its tissues and organs. Neutrophils are the major components of white blood cells in circulation, play a vital role in innate immunity while fighting against infections, and are considered a feature determining sepsis classification. There is a plethora of basic research detailing neutrophil functioning, among which, the study of neutrophil extracellular traps is providing novel insights into mechanisms and treatments of sepsis. This review explores their functions, dysfunctions, and influences in the context of sepsis. The interplay between neutrophils and the human microbiome and the impact of DNA methylation on neutrophil function in sepsis are crucial areas of study. The interaction between neutrophils and the human microbiome is complex, particularly in the context of sepsis, where dysbiosis may occur. We highlight the importance of deciphering neutrophils' functional alterations and their epigenetic features in sepsis because it is critical for defining sepsis endotypes and opening up the possibility for novel diagnostic methods and therapy. Specifically, epigenetic signatures are pivotal since they will provide a novel implication for a sepsis diagnostic method when used in combination with the cell-free DNA. Research is exploring how specific patterns of DNA methylation in neutrophils, detectable in cell-free DNA, could serve as biomarkers for the early detection of sepsis.

Exosome-related gene identification and diagnostic model construction in hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury (HIRI) may cause severe hepatic impairment, acute hepatic insufficiency, and multiorgan system collapse. Exosomes can alleviate HIRI. Therefore, this study explored the role of exosomal-related genes (ERGs) in HIRI using bioinformatics to determine the underlying molecular mechanisms and novel diagnostic markers for HIRI. We merged the GSE12720, GSE14951, and GSE15480 datasets obtained from the Gene Expression Omnibus (GEO) database into a combined gene dataset (CGD). CGD was used to identify differentially expressed genes (DEGs) based on a comparison of the HIRI and healthy control cohorts. The impact of these DEGs on HIRI was assessed through gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA). ERGs were retrieved from the GeneCards database and prior studies, and overlapped with the identified DEGs to yield the set of exosome-related differentially expressed genes (ERDEGs). Functional annotations and enrichment pathways of these genes were determined using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Diagnostic models for HIRI were developed using least absolute shrinkage and selection operator (LASSO) regression and support vector machine (SVM) algorithms. Key genes with diagnostic value were identified from the overlap, and single-sample gene-set enrichment analysis (ssGSEA) was conducted to evaluate the immune infiltration characteristics. A molecular regulatory interaction network was established using Cytoscape software to elucidate the intricate regulatory mechanisms of key genes in HIRI. Finally, exosome score (Es) was obtained using ssGSEA and the HIRI group was divided into the Es_High and Es_Low groups based on the median Es. Gene expression was analyzed to understand the impact of all genes in the CGD on HIRI. Finally, the relative expression levels of the five key genes in the hypoxia-reoxygenation (H/R) model were determined using quantitative real-time PCR (qRT-PCR). A total of 3810 DEGs were identified through differential expression analysis of the CGD, and 61 of these ERDEGs were screened. Based on GO and KEGG enrichment analyses, the ERDEGs were mainly enriched in wound healing, MAPK, protein kinase B signaling, and other pathways. GSEA and GSVA revealed that these genes were mainly enriched in the TP53, MAPK, TGF[Formula: see text], JAK-STAT, MAPK, and NFKB pathways. Five key genes (ANXA1, HNRNPA2B1, ICAM1, PTEN, and THBS1) with diagnostic value were screened using the LASSO regression and SVM algorithms and their molecular interaction network was established using Cytoscape software. Based on ssGSEA, substantial variations were found in the expression of 18 immune cell types among the groups (p < 0.05). Finally, the Es of each HIRI patient was calculated. ERDEGs in the Es_High and Es_Low groups were enriched in the IL18, TP53, MAPK, TGF[Formula: see text], and JAK-STAT pathways. The differential expression of these five key genes in the H/R model was verified using qRT-PCR. Herein, five key genes were identified as potential diagnostic markers. Moreover, the potential impact of these genes on pathways and the regulatory mechanisms of their interaction network in HIRI were revealed. Altogether, our findings may serve as a theoretical foundation for enhancing clinical diagnosis and elucidating underlying pathogeneses.

Oleanolic acid alleviating ischemia-reperfusion injury in rat severe steatotic liver via KEAP1/NRF2/ARE

Severe steatosis in donor livers is contraindicated for transplantation due to the high risk of ischemia-reperfusion injury (IRI). Although Ho-1 gene-modified bone marrow mesenchymal stem cells (HO-1/BMMSCs) can mitigate IRI, the role of gut microbiota and metabolites in this protection remains unclear. This study aimed to explore how gut microbiota and metabolites contribute to HO-1/BMMSCs-mediated protection against IRI in severe steatotic livers. Using rat models and cellular models (IAR20 and THLE-2 cells) of steatotic liver IRI, this study revealed that ischemia-reperfusion led to significant liver and intestinal damage, heightened immune responses, impaired liver function, and altered gut microbiota and metabolite profiles in rats with severe steatosis, which were partially reversed by HO-1/BMMSCs transplantation. Integrated microbiome and metabolome analyses identified gut microbial metabolite oleanolic acid as a potential protective agent against IRI. Experimental validation showed that oleanolic acid administration alone alleviated IRI and inhibited ferroptosis in both rat and cellular models. Network pharmacology and molecular docking implicated KEAP1/NRF2 pathway as a potential target of oleanolic acid. Indeed, OA experimentally upregulated NRF2 activity, which underlies its inhibition of ferroptosis and protection against IRI. The gut microbial metabolite OA protects against IRI in severe steatotic liver by promoting NRF2 expression and activity, thereby inhibiting ferroptosis.

Extracellular vesicles containing GAS6 protect the liver from ischemia-reperfusion injury by enhancing macrophage efferocytosis via MerTK-ERK-COX2 signaling

Hepatic ischemia-reperfusion injury (HIRI) is a significant issue during liver transplantation and surgery, contributing to the liver failure or even mortality. Although extracellular vesicles derived from mesenchymal stem cells (MSC-EVs) have shown substantial potentials in cell replacement therapy of various organ ischemia reperfusion injuries (IRIs), the precise mechanisms remain unclear. In this study, we demonstrate that systemic MSC-EVs administration is predominantly absorbed by macrophages, and verified that it could significantly reduce the liver injury and inflammatory response in mice suffering from HIRI. Furthermore, treatment with MSC-EVs induces macrophage polarization toward an anti-inflammatory phenotype. Mechanistically, proteomic profiling reveals an enrichment of growth arrest-specific 6 (GAS6) in MSC-EVs, significantly promoting the activation of myeloid-epithelial-reproductive tyrosine kinase/extracellular regulated protein kinases/cyclooxygenase 2 (MerTK/ERK/COX2) signaling pathway in macrophages and further enhancing their efferocytosis efficiency. Knockdown of GAS6 via lentiviral transfection or inhibition of MerTK using UNC2025 (a MerTK small molecule inhibitor) partially eliminates the protective effects of MSC-EVs on macrophage efferocytosis and liver injury. Overall, our findings support that MSC-EVs enriched GAS6 execute an anti-inflammation effect, highlighting that treatment based on the modulation of macrophage function by MSC-EVs as a promising approach in IRI. HIRI is a thorny problem after liver surgery such as liver transplantation. In a murine model of HIRI, MSC-EVs enriched GAS6 effectively enhance macrophage efferocytosis both in vivo and in vitro through the GAS6/MerTK/ERK/COX2 signaling pathway and significantly mitigate liver injury. This image was drawn by the authors.

tBHQ mitigates fatty liver ischemia-reperfusion injury by activating Nrf2 to attenuate hepatocyte mitochondrial damage and macrophage STING activation

BACKGROUND

Liver ischemia-reperfusion (IR) injury is an inevitable pathophysiological process in various liver surgeries. Previous studies have found that IR injury is exacerbated in fatty liver due to significant hepatocellular damage and macrophage inflammatory activation, though the underlying mechanisms are not fully understood. In this study, we aim to explore the role and mechanism of Nrf2 (Nuclear factor erythroid 2-related factor 2) signaling in regulating hepatocellular damage and macrophage immune response in fatty liver IR injury.

METHODS

The study used high-fat diet-induced fatty liver mice to establish an IR model, alongside an in vitro co-culture system of primary hepatocytes and macrophages. This approach was used to examine mitochondrial dysfunction, oxidative stress, mitochondrial DNA (mtDNA) release, and activation of macrophage STING (Stimulator of interferon genes) signaling. We also conducted recovery verification using H-151 (a STING inhibitor) and tBHQ (an Nrf2 activator).

RESULTS

Compared to the control group, mice on a high-fat diet demonstrated more severe liver IR injury, as evidenced by increased histological damage, elevated liver enzyme levels, and heightened inflammatory markers. The HFD group showed significant oxidative stress and mitochondrial dysfunction and damage post-IR, as indicated by elevated levels of ROS and lipid peroxidation markers, and decreased antioxidant enzyme activity. Elevated mtDNA release from hepatocytes post-IR activated macrophage STING signaling, worsening inflammation and liver damage. However, STING signaling inhibition with H-151 in vivo or employing STING knockout macrophages significantly reduced these injuries. In-depth mechanism studies have found that the transfer of Nrf2 protein into the nucleus of liver cells after IR in fatty liver is reduced. Pre-treatment with tBHQ ameliorated liver oxidative stress, mitochondrial damage and suppressed the macrophage STING signaling activation.

CONCLUSIONS

Our study reveals a novel mechanism where the interaction between hepatocellular damage and macrophage inflammation intensifies liver IR injury in fatty liver. Enhancing Nrf2 activation to protect mitochondrial from oxidative stress damage and inhibiting macrophage STING signaling activation emerge as promising strategies for clinical intervention in fatty liver IR injury.

Icaritin attenuates ischemia-reperfusion injury by anti-inflammation, anti-oxidative stress, and anti-autophagy in mouse liver

BACKGROUND

Hepatic ischemia-reperfusion (IR) injury is a major complication of liver transplantation and gravely affects patient prognosis. Icaritin (ICT), the primary plasma metabolite of icariin (ICA), plays a critical role in anti-inflammatory and immunomodulatory processes. However, the role of ICT in hepatic IR injury remains largely undefined. In this study, we aimed to elucidate the role of ICT in hepatic IR injury.

METHODS

We established hepatic IR injury models in animals, as well as an oxygen-glucose deprivation/reperfusion (OGD/R) cell model. Liver injury in vivo was assessed by measuring serum alanine aminotransferase (ALT) levels, necrotic areas by liver histology and local hepatic inflammatory responses. For in vitro analyses, we implemented flow-cytometric and western blot analyses, transmission electron microscopy, and an mRFP-GFP-LC3 adenovirus reporter assay to assess the effects of ICT on OGD/R injury in AML12 and THLE-2 cell lines. Signaling pathways were explored in vitro and in vivo to identify possible mechanisms underlying ICT action in hepatic IR injury.

RESULTS

Compared to the mouse model group, ICT preconditioning considerably protected the liver against IR stress, and diminished the levels of necrosis/apoptosis and inflammation-related cytokines. In additional studies, ICT treatment dramatically boosted the expression ratios of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR proteins in hepatic cells following OGD/R damage. We also applied LY294002 (a PI3K inhibitor) and RAPA (rapamycin, an mTOR inhibitor), which blocked the protective effects of ICT in hepatocytes subjected to OGD/R.

CONCLUSION

This study indicates that ICT attenuates ischemia-reperfusion injury by exerting anti-inflammation, anti-oxidative stress, and anti-autophagy effects, as demonstrated in mouse livers. We thus posit that ICT could have therapeutic potential for the treatment of hepatic IR injury.

Neutrophil extracellular traps and citrullinated fibrinogen contribute to injury in a porcine model of limb ischemia and reperfusion

Background

Ischemia/reperfusion injury (IRI) is a complex pathological process, triggered by the restoration of blood flow following an interrupted blood supply. While restoring the blood flow is the only option to salvage the ischemic tissue, reperfusion after a prolonged period of ischemia initiates IRI, triggering a cascade of inflammatory responses ultimately leading to neutrophil recruitment to the inflamed tissue, where they release neutrophil extracellular traps (NETs). NETs are web-like structures of decondensed chromatin and neutrophilic proteins, including peptidyl-arginine deiminase 2 and 4 (PAD2, PAD4), that, once outside, can citrullinate plasma proteins, irreversibly changing their conformation and potentially their function. While the involvement of NETs in IRI is known mainly from rodent models, we aimed to determine the effect of NET formation and especially PADs-mediated extracellular protein citrullination in a porcine model of limb IRI.

Methods

We conducted our study on amputated pig forelimbs exposed to 1 h or 9 h of ischemia and then reperfused in vivo for 12 h. Limb weight, edema formation, compartmental pressure were measured, and skeletal muscle was analyzed by immunofluorescence (TUNEL assay and dystrophin staining) to evaluate tissue damage. Fibrin tissue deposition, complement deposition and NETs were investigated by immunofluorescence. Citrullinated plasma proteins were immunoprecipitated and citrullinated fibrinogen was identified in the plasma by Western blot and in the tissue by immunofluorescence and Western blot.

Results

Our data consolidate the involvement of NETs in a porcine model of limb IRI, correlating their contribution to damage extension with the duration of the ischemic time. We found a massive infiltration of NETs in the group subjected to 9 h ischemia compared to the 1 h and citrullinated fibrinogen levels, in plasma and tissue, were higher in 9 h ischemia group. We propose fibrinogen citrullination as one of the mechanisms contributing to the worsening of IRI. NETs and protein citrullination represent a potential therapeutic target, but approaches are still a matter of debate. Here we introduce the idea of therapeutic approaches against citrullination to specifically inhibit PADs extracellularly, avoiding the downstream effects of hypercitrullination and keeping PADs' and NETs' intracellular regulatory functions.

IL-1 receptor-associated kinase family proteins: An overview of their role in liver disease

The interleukin-1 receptor-associated kinase (IRAK) family is a group of serine-threonine kinases that regulates various cellular processes via toll-like receptor (TLR)/interleukin-1 receptor (IL1R)-mediated signaling. The IRAK family comprises four members, including IRAK1, IRAK2, IRAK3, and IRAK4, which play an important role in the expression of various inflammatory genes, thereby contributing to the inflammatory response. IRAKs are key proteins in chronic and acute liver diseases, and recent evidence has implicated IRAK family proteins (IRAK1, IRAK3, and IRAK4) in the progression of liver-related disorders, including alcoholic liver disease, non-alcoholic steatohepatitis, hepatitis virus infection, acute liver failure, liver ischemia-reperfusion injury, and hepatocellular carcinoma. In this article, we provide a comprehensive review of the role of IRAK family proteins and their associated inflammatory signaling pathways in the pathogenesis of liver diseases. The purpose of this study is to explore whether IRAK family proteins can serve as the main target for the treatment of liver related diseases.

Polyethylene glycol and caspase inhibitor emricasan alleviate cold injury in primary rat hepatocytes

Current methods of storing explanted donor livers at 4 °C in University of Wisconsin (UW) solution result in loss of graft function and ultimately lead to less-than-ideal outcomes post transplantation. Our lab has previously shown that supplementing UW solution with 35-kilodalton polyethylene glycol (PEG) has membrane stabilizing effects for cold stored primary rat hepatocytes in suspension. Expanding on past studies, we here investigate if PEG has the same beneficial effects in an adherent primary rat hepatocyte cold storage model. In addition, we investigated the extent of cold-induced apoptosis through treating cold-stored hepatocytes with pan caspase inhibitor emricasan. In parallel to storage at the current cold storage standard of 4 °C, we investigated the effects of lowering the storage temperature to -4 °C, at which the storage solution remains ice-free due to the supercooling phenomenon. We show the addition of 5 % PEG to the storage medium significantly reduced the release of lactate dehydrogenase (LDH) in plated rat hepatocytes and a combinatorial treatment with emricasan maintains hepatocyte viability and morphology following recovery from cold storage. These results show that cold-stored hepatocytes undergo multiple mechanisms of cold-induced injury and that PEG and emricasan treatment in combination with supercooling may improve cell and organ preservation.

Identification and validation of ferroptosis-related hub genes and immune infiltration in liver ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) is a cumulation of pathophysiological processes that involves cell and organelle damage upon blood flow constraint and subsequent restoration. However, studies on overall immune infiltration and ferroptosis in liver ischemia-reperfusion injury (LIRI) are limited. This study explored immune cell infiltration and ferroptosis in LIRI using bioinformatics and experimental validation. The GSE151648 dataset, including 40 matched pairs of pre- and post- transplant liver samples was downloaded for bioinformatic analysis. Eleven hub genes were identified by overlapping differentially expressed genes (DEGs), iron genes, and genes identified through weighted gene co-expression network analysis (WGCNA). Subsequently, the pathway enrichment, transcription factor-target, microRNA-mRNA and protein-protein interaction networks were investigated. The diagnostic model was established by logistic regression, which was validated in the GSE23649 and GSE100155 datasets and verified using cytological experiments. Moreover, several drugs targeting these genes were found in DrugBank, providing a more effective treatment for LIRI. In addition, the expression of 11 hub genes was validated using quantitative real-time polymerase chain reaction (qRT-PCR) in liver transplantation samples and animal models. The expression of the 11 hub genes increased in LIRI compared with the control. Five genes were significantly enriched in six biological process terms, six genes showed high enrichment for LIRI-related signaling pathways. There were 56 relevant transcriptional factors and two central modules in the protein-protein interaction network. Further immune infiltration analysis indicated that immune cells including neutrophils and natural killer cells were differentially accumulated in the pre- and post-transplant groups, and this was accompanied by changes in immune-related factors. Finally, 10 targeted drugs were screened. Through bioinformatics and further experimental verification, we identified hub genes related to ferroptosis that could be used as potential targets to alleviate LIRI.

Exercise Preconditioning of the Donor Liver Decreases Cold Ischemia/Reperfusion Injury in a Mouse Model

BACKGROUND

Liver transplantation stands as the primary treatment for end-stage liver disease, with demand surging in recent decades because of expanded indications. However, hepatic ischemia/reperfusion injury can lead to liver transplant failure in both deceased donor and living donor transplantation. This study explored whether preconditioning donor livers through exercise training (ExT) could mitigate cold ischemic injury posttransplantation.

METHODS

Donor C57BL/6 mice underwent ExT via treadmill running or remained sedentary. After 4 wk, the donor liver underwent cold storage and subsequent orthotopic liver transplantation or ex vivo warm reperfusion.

RESULTS

Donor liver from mice subjected to ExT showed significantly decreased hepatic injury on reperfusion. Tissue histology revealed decreased sinusoidal congestion, vacuolization, and hepatocellular necrosis in livers from ExT mice, and immunofluorescence staining further revealed a decreased number of apoptotic cells in ExT grafts. Livers from ExT donors expressed decreased intragraft inflammatory cytokines cascade, decreased neutrophil infiltration and neutrophil extracellular traps, and increased M2 phenotype of recipient macrophages compared with grafts from sedentary mice. After cold storage, liver grafts from ExT donors showed decreased accumulation of reactive oxygen species and decreased levels of cytochrome c and high mobility group box 1 released in the liver effluent. In addition, ExT grafts showed upregulated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and higher levels of mitochondrial content. Similar effects of decreased hepatic injury were observed in wild-type mice when pretreated with a PGC-1α stimulator ZLN005 instead of ExT.

CONCLUSIONS

These findings suggest that augmenting hepatocytic mitochondrial content through donor exercise or PGC-1α stimulation may offer therapeutic avenues to mitigate postreperfusion inflammation and improve transplant outcomes.

Production of physiological amounts of hemostatic proteins by human donor livers during ex situ long-term normothermic machine perfusion for up to 7 days

BACKGROUND

Normothermic machine perfusion (NMP) is used for preservation and assessment of human donor livers prior to transplantation. During NMP, the liver is metabolically active, which allows detailed studies on the physiology of human livers.

OBJECTIVES

To study the production of hemostatic proteins in human donor livers during NMP for up to 7 days.

METHODS

In this observational study, 9 livers underwent NMP for up to 7 days with a heparinized perfusate based on red blood cells and colloids using a modified Liver Assist device (XVIVO). Perfusate samples were collected before NMP and daily thereafter for measurement of antigen and activity levels of a comprehensive panel of hemostatic proteins after heparin neutralization.

RESULTS

Within 1 day, perfusate samples displayed the potential for coagulation activation as evidenced by international normalized ratio and activated partial thromboplastin assays. This was accompanied by detection of substantial quantities of functionally active coagulation proteins and inhibitors, although the specific activity of many proteins was decreased, compared with that in normal plasma. Perfusate levels of hemostatic proteins increased in the first days, reaching a stable level after 3 to 4 days of perfusion.

CONCLUSION

During long-term NMP of human livers, functionally active hemostatic proteins are released into the perfusate in substantial quantities, but some proteins appear to have decreased functional properties compared with proteins in normal human plasma. We propose that NMP may be used as a platform to test efficacy of drugs that stimulate or inhibit the production of coagulation factors or to test liver-mediated clearance of prohemostatic protein therapeutics.

Pathogenesis and interaction of neutrophils and extracellular vesicles in noncancer liver diseases

Liver disease ranks as the eleventh leading cause of mortality, leading to approximately 2 million deaths annually worldwide. Neutrophils are a type of immune cell that are abundant in peripheral blood and play a vital role in innate immunity by quickly reaching the site of liver injury. They exert their influence on liver diseases through autocrine, paracrine, and immunomodulatory mechanisms. Extracellular vesicles, phospholipid bilayer vesicles, transport a variety of substances, such as proteins, nucleic acids, lipids, and pathogenic factors, for intercellular communication. They regulate cell communication and perform their functions by delivering biological information. Current research has revealed the involvement of the interaction between neutrophils and extracellular vesicles in the pathogenesis of liver disease. Moreover, more research has focused on targeting neutrophils as a therapeutic strategy to attenuate disease progression. Therefore, this article summarizes the roles of neutrophils, extracellular vesicles, and their interactions in noncancerous liver diseases.

Sunitinib alleviates hepatic ischemia reperfusion injury by inhibiting the JAK2/STAT pathway and promoting the M2 polarization of macrophages

BACKGROUND

Hepatic ischemia reperfusion injury (IRI) is a common liver surgery complication. This study aims to explore the effect and potential mechanism of Sunitinib - a multi-target tyrosine kinase inhibitor - on hepatic IRI.

METHODS

We established a hepatic IRI model using C57BL/6 mice, and integrated 40 mg/kg of Sunitinib, solely or combined with 100 μg/kg of coumermycin A1 (C-A1), in the treatment strategy. H&E staining, TUNEL assay, and detection of serum ALT and AST activities were used to assess liver damage. Further, ELISA kits and Western Blots were utilized to determine IL-1β, TNF-α, IL-6, CXCL10, and CXCL2 levels. Primary macrophages, once isolated, were cultured in vitro with either 2 nM of Sunitinib, or Sunitinib in conjunction with 1 μM of C-A1, to gauge their influence on macrophage polarization. qPCR and Western blot were conducted to examine the level of p-STAT1/STAT1, p-STAT3/STAT3, p-JAK2/JAK2, and M1/M2 polarization markers. To quantify immune cell infiltration, we applied Immunofluorescence.

RESULTS

Sunitinib pretreatment significantly alleviated liver injury and reduced p-STAT1/STAT1, p-STAT3/STAT3, p-JAK2/JAK2 levels. In vitro, Sunitinib treatment curbed M1 polarization induced by LPS + IFN-γ and bolstered M2 polarization triggered by IL-4. C-A1 application upregulated JAK2/STAT pathway phosphorylation and promoted LPS + IFN-γ-induced M1 polarization, which was reversed by Sunitinib treatment. In IL-4-stimulated macrophages, application of C-A1 activated the JAK2/STAT pathway and decreased M2-type macrophages, which was reversed by Sunitinib treatment either.

CONCLUSION

Sunitinib is capable of guiding the polarization of macrophages toward an M2-type phenotype via the inhibition of the JAK2/STAT pathway, thereby exerting a protective effect on hepatic IRI.

Controlling Pericellular Oxygen Tension in Cell Culture Reveals Distinct Breast Cancer Responses to Low Oxygen Tensions

In oxygen (O2)-controlled cell culture, an indispensable tool in biological research, it is presumed that the incubator setpoint equals the O2 tension experienced by cells (i.e., pericellular O2). However, it is discovered that physioxic (5% O2) and hypoxic (1% O2) setpoints regularly induce anoxic (0% O2) pericellular tensions in both adherent and suspension cell cultures. Electron transport chain inhibition ablates this effect, indicating that cellular O2 consumption is the driving factor. RNA-seq analysis revealed that primary human hepatocytes cultured in physioxia experience ischemia-reperfusion injury due to cellular O2 consumption. A reaction-diffusion model is developed to predict pericellular O2 tension a priori, demonstrating that the effect of cellular O2 consumption has the greatest impact in smaller volume culture vessels. By controlling pericellular O2 tension in cell culture, it is found that hypoxia vs. anoxia induce distinct breast cancer transcriptomic and translational responses, including modulation of the hypoxia-inducible factor (HIF) pathway and metabolic reprogramming. Collectively, these findings indicate that breast cancer cells respond non-monotonically to low O2, suggesting that anoxic cell culture is not suitable for modeling hypoxia. Furthermore, it is shown that controlling atmospheric O2 tension in cell culture incubators is insufficient to regulate O2 in cell culture, thus introducing the concept of pericellular O2-controlled cell culture.

Bile acids attenuate hepatic inflammation during ischemia/reperfusion injury

Background & Aims

Persistent cholestasis has been associated with poor prognosis after orthotopic liver transplantation. In this study, we aimed to investigate how the accumulation of tauro-beta-muricholic acid (TβMCA), resulting from the reprogramming of bile acid (BA) metabolism during liver ischemia/reperfusion (IR) stress, attenuates liver inflammation.

Methods

Ingenuity Pathway Analysis was performed using transcriptome data from a murine hepatic IR model. Three different models of hepatic IR (liver warm IR, bile duct separation-IR, common bile duct ligation-IR) were employed. We generated adeno-associated virus-transfected mice and CD11b-DTR mice to assess the role of BAs in regulating the myeloid S1PR2-GSDMD axis. Hepatic BA levels were analyzed using targeted metabolomics. Finally, the correlation between the reprogramming of BA metabolism and hepatic S1PR2 levels was validated through RNA-seq of human liver transplant biopsies.

Results

We found that BA metabolism underwent reprogramming in murine hepatocytes under IR stress, leading to increased synthesis of TβMCA, catalyzed by the enzyme CYP2C70. The levels of hepatic TβMCA were negatively correlated with the severity of hepatic inflammation, as indicated by the serum IL-1β levels. Inhibition of hepatic CYP2C70 resulted in reduced TβMCA production, which subsequently increased serum IL-1β levels and exacerbated IR injury. Moreover, our findings suggested that TβMCA could inhibit canonical inflammasome activation in macrophages and attenuate inflammatory responses in a myeloid-specific S1PR2-GSDMD-dependent manner. Additionally, Gly-βMCA, a derivative of TβMCA, could effectively attenuate inflammatory injury in vivo and inhibit human macrophage pyroptosis in vitro.

Conclusions

IR stress orchestrates hepatic BA metabolism to generate TβMCA, which attenuates hepatic inflammatory injury by inhibiting the myeloid S1PR2-GSDMD axis. Bile acids have immunomodulatory functions in liver reperfusion injury that may guide therapeutic strategies.

Impact and implications

Our research reveals that liver ischemia-reperfusion stress triggers reprogramming of bile acid metabolism. This functions as an adaptive mechanism to mitigate inflammatory injury by regulating the S1PR2-GSDMD axis, thereby controlling the release of IL-1β from macrophages. Our results highlight the crucial role of bile acids in regulating hepatocyte-immune cell crosstalk, which demonstrates an immunomodulatory function in liver reperfusion injury that may guide therapeutic strategies targeting bile acids and their receptors.

Mesenchymal Stem Cell Membrane-Camouflaged Liposomes for Biomimetic Delivery of Cyclosporine A for Hepatic Ischemia-Reperfusion Injury Prevention

Hepatic ischemia-reperfusion injury (HIRI) is a prevalent issue during liver resection and transplantation, with currently no cure or FDA-approved therapy. A promising drug, Cyclosporin A (CsA), ameliorates HIRI by maintaining mitochondrial homeostasis but has systemic side effects due to its low bioavailability and high dosage requirements. This study introduces a biomimetic CsA delivery system that directly targets hepatic lesions using mesenchymal stem cell (MSC) membrane-camouflaged liposomes. These hybrid nanovesicles (NVs), leveraging MSC-derived proteins, demonstrate efficient inflammatory chemotaxis, transendothelial migration, and drug-loading capacity. In a HIRI mouse model, the biomimetic NVs accumulated at liver injury sites entered hepatocytes, and significantly reduced liver damage and restore function using only one-tenth of the CsA dose typically required. Proteomic analysis verifies the protection mechanism, which includes reactive oxygen species inhibition, preservation of mitochondrial integrity, and reduced cellular apoptosis, suggesting potential for this biomimetic strategy in HIRI intervention.

Dietary sulforaphane glucosinolate mitigates depression-like behaviors in mice with hepatic ischemia/reperfusion injury: A role of the gut-liver-brain axis

Nutrition has been increasingly recognized for its use in mental health. Depression is commonly observed in patients with chronic liver disease (CLD). Building on our recent findings of depression-like behaviors in mice with hepatic ischemia/reperfusion (HI/R) injury, mediated by the gut-liver-brain axis, this study explored the potential influence of dietary sulforaphane glucosinolate (SGS) on these behaviors. Behavioral assessments for depression-like behaviors were conducted 7 days post either sham or HI/R injury surgery. Dietary intake of SGS significantly prevented splenomegaly, systemic inflammation, depression-like behaviors, and downregulation of synaptic proteins in the prefrontal cortex (PFC) of HI/R-injured mice. Through 16S rRNA analysis and untargeted metabolomic analyses, distinct bacterial profiles and metabolites were identified between control + HI/R group and SGS + HI/R group. Correlations were observed between the relative abundance of gut microbiota and both behavioral outcomes and blood metabolites. These findings suggest that SGS intake could mitigate depression-like phenotypes in mice with HI/R injury, potentially through the gut-liver-brain axis. Additionally, SGS, found in crucial vegetables like broccoli, could offer prophylactic nutritional benefits for depression in patients with CLD.

Mid1 aggravates hepatic ischemia-reperfusion injury by inducing immune cell infiltration

Hepatic ischemia-reperfusion injury (HIRI) represents a major risk factor in liver transplantation and resection surgeries. Kupffer cells (KCs) produce proinflammatory cytokines and lead to hepatic neutrophil infiltration in the liver, which is one of the leading causes of HIRI. Mid1 is involved in immune infiltration, but the role of Mid1 remains poorly understood. Herin, our study aimed to investigate the effect of Mid1 on HIRI progression. Male C57BL/6 mice aged 6 weeks were used for the HIRI model established. The function of Mid1 on liver injury and hepatic inflammation was evaluated. In vitro, KCs were used to investigate the function and mechanism of Mid1 in modulating KC inflammation upon lipopolysaccharide (LPS) stimulation. We found that Mid1 expression was up-regulated upon HIRI. Mid1 inhibition alleviated liver damage, as evidenced by neutrophil infiltration, intrahepatic inflammation, and hepatocyte apoptosis. In vitro experiments further revealed that Mid1 knockdown reduced the secretion of proinflammatory cytokines and chemokines in KCs. Moreover, silenced-Mid1 suppressed proinflammatory responses by the inhibition of NF-κB, JNK, and p38 signaling pathways. Taken together, Mid1 contributes to HIRI via regulating the proinflammatory response of KCs and inducing neutrophil infiltration. Targeting Mid1 may be a promising strategy to protect against HIRI.

Self-Sulfhydrated, Nitro-Fixed Albumin Nanoparticles as a Potent Therapeutic Agent for the Treatment of Acute Liver Injury

Exogenous polysulfhydryls (R-SH) supplementation and nitric oxide (NO) gas molecules delivery provide essential antioxidant buffering pool components and anti-inflammatory species in cellular defense against injury, respectively. Herein, the intermolecular disulfide bonds in bovine serum albumin (BSA) molecules were reductively cleaved under native and mild conditions to expose multiple sulfhydryl groups (BSA-SH), then sulfhydryl-nitrosylated (R-SNO), and nanoprecipitated to form injectable self-sulfhydrated, nitro-fixed albumin nanoparticles (BSA-SNO NPs), allowing albumin to act as a NO donor reservoir and multiple sulfhydryl group transporter while also preventing unfavorable oxidation and self-cross-linking of polysulfhydryl groups. In two mouse models of ischemia/reperfusion-induced and endotoxin-induced acute liver injury (ALI), a single low dosage of BSA-SNO NPs (S-nitrosothiols: 4 μmol·kg-1) effectively attenuated oxidative stress and systemic inflammation cascades in the upstream pathophysiology of disease progression, thus rescuing dying hepatocytes, regulating host defense, repairing microcirculation, and restoring liver function. By mechanistically upregulating the antioxidative signaling pathway (Nrf-2/HO-1/NOQ1) and inhibiting the inflammatory cytokine storm (NF-κB/p-IκBα/TNF-α/IL-β), BSA-SNO NPs blocked the initiation of the mitochondrial apoptotic signaling pathway (Cyto C/Bcl-2 family/caspase-3) and downregulated the cell pyroptosis pathway (NLRP3/ASC/IL-1β), resulting in an increased survival rate from 26.7 to 73.3%. This self-sulfhydrated, nitro-fixed functionalized BSA nanoformulation proposes a potential drug-free treatment strategy for ALI.

Programmed cell death, from liver Ischemia-Reperfusion injury perspective: An overview

Liver ischemia-reperfusion injury (LIRI) commonly occurs in liver resection, liver transplantation, shock, and other hemorrhagic conditions, resulting in profound local and systemic effects via associated inflammatory responses and hepatic cell death. Hepatocyte death is a significant component of LIRI and its mechanism was previously thought to be limited to apoptosis and necrosis. With the discovery of novel types of programmed cell death (PCD), necroptosis, ferroptosis, pyroptosis, autophagy, NETosis, and parthanatos have been shown to be involved in LIRI. Understanding the mechanisms underlying cell death following LIRI is indispensable to mitigating the widespread effects of LIRI. Here, we review the roles of different PCD and discuss potential therapy in LIRI.

Glycogen synthase kinase-3β: A multifaceted player in ischemia-reperfusion injury and its therapeutic prospects

Ischemia-reperfusion injury (IRI) results in irreversible metabolic dysfunction and structural damage to tissues or organs, posing a formidable challenge in the field of organ implantation, cardiothoracic surgery, and general surgery. Glycogen synthase kinase-3β (GSK-3β) a multifunctional serine/threonine kinase, is involved in a variety of biological processes, including cell proliferation, apoptosis, and immune response. Phosphorylation of its tyrosine 216 and serine 9 sites positively and negatively regulates the activation and inactivation of the enzyme. Significantly, inhibition or inactivation of GSK-3β provides protection against IRI, making it a viable target for drug development. Though numerous GSK-3β inhibitors have been identified to date, the development of therapeutic treatments remains a considerable distance away. In light of this, this review summarizes the complicated network of GSK-3β roles in IRI. First, we provide an overview of GSK-3β's basic background. Subsequently, we briefly review the pathological mechanisms of GSK-3β in accelerating IRI, and highlight the latest progress of GSK-3β in multiorgan IRI, encompassing heart, brain, kidney, liver, and intestine. Finally, we discuss the current development of GSK-3β inhibitors in various organ IRI, offering a thorough and insightful reference for GSK-3β as a potential target for future IRI therapy.

Mild hypothermia pretreatment improves hepatic ischemia-reperfusion injury: A systematic review and meta-analysis of animal experiments

BACKGROUND AND AIM

Mild hypothermia in hepatic ischemia-reperfusion injury is increasingly being studied. This study aimed to conduct a systematic evaluation of the effectiveness of mild hypothermia in improving hepatic ischemia-reperfusion injury.

METHODS

We systematically searched CNKI, WanFang Data, PubMed, Embase, and Web of Science for original studies that used animal experiments to determine how mild hypothermia(32-34°C) pretreatment improves hepatic ischemia-reperfusion injury(in situ 70% liver IR model). The search period ranged from the inception of the databases to May 5, 2023. Two researchers independently filtered the literature, extracted the data, and assessed the risk of bias incorporated into the study. The meta-analysis was performed using RevMan 5.4.1 and Stata 15 software.

RESULTS

Eight randomized controlled trials (RCTs) involving a total of 117 rats/mice were included. The results showed that the ALT levels in the mild hypothermia pretreatment group were significantly lower than those in the normothermic control group [Standardized Mean Difference (SMD) = -5.94, 95% CI(-8.09, -3.78), P<0.001], and AST levels in the mild hypothermia pretreatment group were significantly lower than those in the normothermic control group [SMD = -4.45, 95% CI (-6.10, -2.78), P<0.001]. The hepatocyte apoptosis rate in the mild hypothermia pretreatment group was significantly lower than that in the normothermic control group [SMD = -6.86, 95% CI (-10.38, -3.33), P<0.001]. Hepatocyte pathology score in the mild hypothermia pretreatment group was significantly lower than that in the normothermic control group [SMD = -4.36, 95% CI (-5.78, -2.95), P<0.001]. There was no significant difference in MPO levels between the mild hypothermia preconditioning group and the normothermic control group [SMD = -4.83, 95% CI (-11.26, 1.60), P = 0.14]. SOD levels in the mild hypothermia preconditioning group were significantly higher than those in the normothermic control group [SMD = 3.21, 95% CI (1.27, 5.14), P = 0.001]. MDA levels in the mild hypothermia pretreatment group were significantly lower than those in the normothermic control group [SMD = -4.06, 95% CI (-7.06, -1.07) P = 0.008].

CONCLUSION

Mild hypothermia can attenuate hepatic ischemia-reperfusion injury, effectively reduce oxidative stress and inflammatory response, prevent hepatocyte apoptosis, and protect liver function.

Oridonin attenuates liver ischemia-reperfusion injury by suppressing PKM2/NLRP3-mediated macrophage pyroptosis

BACKGROUND

The NOD-like receptor protein 3 (NLRP3) mediated pyroptosis of macrophages is closely associated with liver ischemia reperfusion injury (IRI). As a covalent inhibitor of NLRP3, Oridonin (Ori), has strong anti-inflammasome effect, but its effect and mechanisms for liver IRI are still unknown.

METHODS

Mice and liver macrophages were treated with Ori, respectively. Co-IP and LC-MS/MS analysis of the interaction between PKM2 and NLRP3 in macrophages. Liver damage was detected using H&E staining. Pyroptosis was detected by WB, TEM, and ELISA.

RESULTS

Ori ameliorated liver macrophage pyroptosis and liver IRI. Mechanistically, Ori inhibited the interaction between pyruvate kinase M2 isoform (PKM2) and NLRP3 in hypoxia/reoxygenation（H/R）-induced macrophages, while the inhibition of PKM2/NLRP3 reduced liver macrophage pyroptosis and liver IRI.

CONCLUSION

Ori exerted protective effects on liver IRI via suppressing PKM2/NLRP3-mediated liver macrophage pyroptosis, which might become a potential therapeutic target in the clinic.

The potential role of Hypericum perforatum in wound healing: A literature review on the phytochemicals, pharmacological approaches, and mechanistic perspectives

St. John's Wort, commonly known as Hypericum perforatum L., is a flowering plant in the Clusiaceae family that traditionally been employed for treating anxiety, depression, wounds, burns, sunburn, irritation, and stomach ailments. This review provides a synopsis of H. perforatum L. phytoconstituents and their biological effects, highlighting its beneficial therapeutic properties for dermatological indications, as well as its antioxidant, antimicrobial, anti-inflammatory, and anti-angiogenic activity in various applications including wound healing and skin conditions such as eczema, sun burn and minor burns also spastic paralysis, stiff neck and mood disorders as anti-depressant and nerve pains such as neuralgia. The data were collected from several databases as Web of Science PubMed, ScienceDirect, Scopus and Google Scholar using the terms: "H. perforatum L.", "H. perforatum L. /phytochemistry," and "H. perforatum extracts/wound healing" collected from 1994 to 2023. The findings suggest H. perforatum L. acts through various mechanisms and plays a role in each phase of the wound healing process, including re-epithelialization, angiogenesis, wound contraction, and connective tissue regeneration. H. perforatum L. enhances collagen deposition, decreases inflammation, inhibits fibroblast migration, and promotes epithelialization by increasing the number of fibroblasts with polygonal shape and the number of collagen fibers within fibroblasts. H. Perforatum L. extracts modulate the immune response and reduce inflammation were found to accelerate the wound healing process via inhibition of inflammatory mediators' production like interleukin-6, tumor necrosis factor-α, cyclooxygenase-2 gene expression, and inducible nitric oxide synthase. Thus, H. perforatum L. represents a potential remedy for a wide range of dermatological problems, owing to its constituents with beneficial therapeutic properties. H. perforatum L. could be utilized in the development of novel wound healing therapies.

Gradual rewarming with a hemoglobin-based oxygen carrier improves viability of donation after circulatory death in rat livers

Background

Donation after circulatory death (DCD) grafts are vital for increasing available donor organs. Gradual rewarming during machine perfusion has proven effective in mitigating reperfusion injury and enhancing graft quality. Limited data exist on artificial oxygen carriers as an effective solution to meet the increasing metabolic demand with temperature changes. The aim of the present study was to assess the efficacy and safety of utilizing a hemoglobin-based oxygen carrier (HBOC) during the gradual rewarming of DCD rat livers.

Methods

Liver grafts were procured after 30 min of warm ischemia. The effect of 90 min of oxygenated rewarming perfusion from ice cold temperatures (4 °C) to 37 °C with HBOC after cold storage was evaluated and the results were compared with cold storage alone. Reperfusion at 37 °C was performed to assess the post-preservation recovery.

Results

Gradual rewarming with HBOC significantly enhanced recovery, demonstrated by markedly lower lactate levels and reduced vascular resistance compared to cold-stored liver grafts. Increased bile production in the HBOC group was noted, indicating improved liver function and bile synthesis capacity. Histological examination showed reduced cellular damage and better tissue preservation in the HBOC-treated livers compared to those subjected to cold storage alone.

Conclusion

This study suggests the safety of using HBOC during rewarming perfusion of rat livers as no harmful effect was detected. Furthermore, the viability assessment indicated improvement in graft function.

Mechanism of Reactive Oxygen/Nitrogen Species in Liver Ischemia-Reperfusion Injury and Preventive Effect of Chinese Medicine

Liver ischemia-reperfusion injury (LIRI) is a pathological process involving multiple injury factors and cell types, with different stages. Currently, protective drugs targeting a single condition are limited in efficacy, and interventions on immune cells will also be accompanied by a series of side effects. In the current bottleneck research stage, the multi-target and obvious clinical efficacy of Chinese medicine (CM) is expected to become a breakthrough point in the research and development of new drugs. In this review, we summarize the roles of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in various stages of hepatic ischemia-reperfusion and on various types of cells. Combined with the current research progress in reducing ROS/RNS with CM, new therapies and mechanisms for the treatment of hepatic ischemia-reperfusion are discussed.

Research progress on the role of mitochondria in the process of hepatic ischemia-reperfusion injury

During liver ischemia-reperfusion injury, existing mechanisms involved oxidative stress, calcium overload, and the activation of inflammatory responses involve mitochondrial injury. Mitochondrial autophagy, a process that maintains the normal physiological activity of mitochondria, promotes cellular metabolism, improves cellular function, and facilitates organelle renewal. Mitochondrial autophagy is involved in oxidative stress and apoptosis, of which the PINK1-Parkin pathway is a major regulatory pathway, and the deletion of PINK1 and Parkin increases mitochondrial damage, reactive oxygen species production, and inflammatory response, playing an important role in mitochondrial quality regulation. In addition, proper mitochondrial permeability translational cycle regulation can help maintain mitochondrial stability and mitigate hepatocyte death during ischemia-reperfusion injury. This mechanism is also closely related to oxidative stress, calcium overload, and the aforementioned autophagy pathway, all of which leads to the augmentation of the mitochondrial membrane permeability transition pore opening and cause apoptosis. Moreover, the release of mitochondrial DNA (mtDNA) due to oxidative stress further aggravates mitochondrial function impairment. Mitochondrial fission and fusion are non-negligible processes required to maintain the dynamic renewal of mitochondria and are essential to the dynamic stability of these organelles. The Bcl-2 protein family also plays an important regulatory role in the mitochondrial apoptosis signaling pathway. A series of complex mechanisms work together to cause hepatic ischemia-reperfusion injury (HIRI). This article reviews the role of mitochondria in HIRI, hoping to provide new therapeutic clues for alleviating HIRI in clinical practice.

A comprehensive analysis of m6A/m7G/m5C/m1A-related gene expression and immune infiltration in liver ischemia-reperfusion injury by integrating bioinformatics and machine learning algorithms

BACKGROUND

Liver ischemia-reperfusion injury (LIRI) is closely associated with immune infiltration, which commonly occurs after liver surgery, especially liver transplantation. Therefore, it is crucial to identify the genes responsible for LIRI and develop effective therapeutic strategies that target immune response. Methylation modifications in mRNA play various crucial roles in different diseases. This study aimed to identify potential methylation-related markers in patients with LIRI and evaluate the corresponding immune infiltration.

METHODS

Two Gene Expression Omnibus datasets containing human liver transplantation data (GSE12720 and GSE151648) were downloaded for integrated analysis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were conducted to investigate the functional enrichment of differentially expressed genes (DEGs). Differentially expressed methylation-related genes (DEMRGs) were identified by overlapping DEG sets and 65 genes related to N6-methyladenosine (m6A), 7-methylguanine (m7G), 5-methylcytosine (m5C), and N1-methyladenosine (m1A). To evaluate the relationship between DEMRGs, a protein-protein interaction (PPI) network was utilized. The core DEMRGs were screened using three machine learning algorithms: least absolute shrinkage and selection operator, random forest, and support vector machine-recursive feature elimination. After verifying the diagnostic efficacy using the receiver operating characteristic curve, we validated the expression of the core DEMRGs in clinical samples and performed relative cell biology experiments. Additionally, the immune status of LIRI was comprehensively assessed using the single sample gene set enrichment analysis algorithm. The upstream microRNA and transcription factors of the core DEMRGs were also predicted.

RESULTS

In total, 2165 upregulated and 3191 downregulated DEGs were identified, mainly enriched in LIRI-related pathways. The intersection of DEGs and methylation-related genes yielded 28 DEMRGs, showing high interaction in the PPI network. Additionally, the core DEMRGs YTHDC1, METTL3, WTAP, and NUDT3 demonstrated satisfactory diagnostic efficacy and significant differential expression and corresponding function based on cell biology experiments. Furthermore, immune infiltration analyses indicated that several immune cells correlated with all core DEMRGs in the LIRI process to varying extents.

CONCLUSIONS

We identified core DEMRGs (YTHDC1, METTL3, WTAP, and NUDT3) associated with immune infiltration in LIRI through bioinformatics and validated them experimentally. This study may provide potential methylation-related gene targets for LIRI immunotherapy.

Activation of the PPARγ/NF-κB pathway by A-MPDA@Fe3O4@PVP via scavenging reactive oxygen species to alleviate hepatic ischemia-reperfusion injury

Hepatic ischemia-reperfusion injury (IRI) is a common pathological process during hepatectomy and liver transplantation and the two primary reasons for hepatic IRI are reactive oxygen species (ROS)-mediated oxidative stress and excessive inflammatory responses. Herein, a novel antioxidant nanodrug (A-MPDA@Fe3O4@PVP) is prepared by employing L-arginine-doped mesoporous polydopamine (A-MPDA) nanoparticles as the carrier for deposition of ultra-small ferric oxide (Fe3O4) nanoparticles and further surface modification with polyvinylpyrrolidone (PVP). A-MPDA@Fe3O4@PVP not only effectively reduces the aggregation of ultra-small Fe3O4, but also simultaneously replicates the catalytic activity of catalase (CAT) and superoxide dismutase (SOD). A-MPDA@Fe3O4@PVP with good antioxidant activity can rapidly remove various toxic reactive oxygen species (ROS) and effectively regulate macrophage polarization in vitro. In the treatment of hepatic IRI, A-MPDA@Fe3O4@PVP effectively alleviates ROS-induced oxidative stress, reduces the expression of inflammatory factors, and prevents apoptosis of hepatocytes through immune regulation. A-MPDA@Fe3O4@PVP can further protect liver tissue by activating the PPARγ/NF-κB pathway. This multiplex antioxidant enzyme therapy can provide new references for the treatment of IRI in organ transplantation and other ROS-related injuries such as fibrosis, cirrhosis, and bacterial and hepatic viral infection.

CX3CR1 deficiency promotes resolution of hepatic ischemia-reperfusion injury by regulating homeostatic function of liver infiltrating macrophages

Hepatic ischemia-reperfusion injury(HIRI) remains to be an unsolved risk factor that contributes to organ failure after liver surgery. Our clinical retrospective study showed that lower donor liver CX3-C chemokine receptor-1(CX3CR1) mRNA expression level were correlated with upregulated pro-resolved macrophage receptor MERTK, as well as promoted restoration efficiency of allograft injury in liver transplant. To further characterize roles of CX3CR1 in regulating resolution of HIRI, we employed murine liver partial warm ischemia-reperfusion model by Wt & Cx3cr1-/- mice and the reperfusion time was prolonged from 6 h to 4-7 days. Kupffer cells(KCs) were depleted by clodronate liposome(CL) in advance to focus on infiltrating macrophages, and repopulation kinetics were determined by FACS, IF and RNA-Seq. CX3CR1 antagonist AZD8797 was injected i.p. to interrogate potential pharmacological therapeutic strategies. In vitro primary bone marrow macrophages(BMMs) culture by LXR agonist DMHCA, as well as molecular and functional studies, were undertaken to dissect roles of CX3CR1 in modulating macrophages cytobiological development and resolutive functions. We observed that deficiency or pharmacological inhibition of CX3CR1 facilitated HIRI resolution via promoted macrophages migration in CCR1/CCR5 manner, as well as enhanced MerTK-mediated efferocytosis. Our study demonstrated the critical roles of CX3CR1 in progression of HIRI and identified it as a potential therapeutic target in clinical liver transplantation.

METTL3 Modulates TXNIP Expression to Affect the Activation of NLRP3 Inflammasome in Hepatic Cells Under Oxygen-Glucose Deprivation/Reperfusion Injury

Hepatic ischemia-reperfusion (I/R) injury is still a major risk factor and unsolved problem in hepatic surgery. Methyltransferase-like 3 (METTL3), an important m6A-modified methylase, regulates inflammation and cellular stress response. In this study, we demonstrated the special role of METTL3 and its underlying mechanism in hepatic I/R injury. In the mouse model of hepatic I/R and in the oxygen-glucose deprivation and reoxygenation (OGD/R)-induced AML12 and NCTC 1469 cells, the expression of METTL3 was significantly upregulated. Inhibition of METTL3 in OGD/R-induced AML12 and NCTC 1469 cells both increased the cell viability, declined the cell apoptosis, and decreased the reactive oxygen species (ROS) and the release levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18), diminishing NLRP3 and Caspase1-p20 expressions. Moreover, METTL3 positively modulated TXNIP expression in an m6A manner. TXNIP overexpression reversed the effects of METTL3 knockdown on OGD/R-induced injury in AML12 cells. Furthermore, inhibition of NLRP3 inflammasome activity contributed to the protective effects of TXNIP knockdown in OGD/R-induced AML12 cells. In conclusion, METTL3 knockdown alleviated OGD/R-induced hepatocyte injury, and the specific mechanism was associated with the inhibition of NLRP3 inflammasome activation, which was attributed to the reduction of TXNIP in an m6A-dependent manner.

Human umbilical cord mesenchymal stem cells alleviate fatty liver ischemia-reperfusion injury by activating autophagy through upregulation of IFNγ

Liver ischemia-reperfusion injury (IRI) is an important factor affecting the prognosis of liver transplantation, and extended criteria donors (e.g., steatosis donor livers) are considered to be more sensitive to ischemia-reperfusion injury in liver transplantation. Currently, the application of human umbilical cord mesenchymal stem cells (hMSCs) has great promise in the treatment of various injuries in the liver. This study aimed to investigate the therapeutic role and mechanism of hMSCs in fatty liver IRI. After more than 8 weeks of high-fat chow feeding, we constructed a fatty liver mouse model and established ischemic injury of about 70% of the liver. Six hours after IRI, liver injury was significantly alleviated in hMSCs-treated mice, and the expression levels of liver enzyme, inflammatory factor TNF-α, and apoptotic proteins were significantly lower than those of the control group, which were also significant in pathological sections. Transcriptomics analysis showed that IFNγ was significantly upregulated in the hMSCs group. Mechanistically, IFNγ, which activates the MAPK pathway, is a potent agonist that promotes the occurrence of autophagy in hepatocytes to exert a protective function, which was confirmed by in vitro experiments. In summary, hMSCs treatment could slow down IRI in fatty liver by activating autophagy through upregulation of IFNγ, and this effect was partly direct.

Crocetin preconditioning attenuates ischemia reperfusion-induced hepatic injury by disrupting Keap1/Nrf2 interaction and activating Nrf2/HO-1 pathway

BACKGROUND

Ischemia reperfusion (I/R) injury is a frequent occurrence during liver transplantation surgery, resulting from the temporary cessation of blood flow and subsequent restoration of blood flow. Serious I/R injury is a significant factor causing transplant failure. Hepatic I/R process is characterized by excessive inflammation, oxidation, and apoptosis. Crocetin (Crt) is a natural compound exhibiting beneficial roles in various I/R-induced organ damages. However, Crt's potential role in hepatic I/R remains unexplored.

OBJECTIVE AND METHODS

In order to reveal the impact of Crt on hepatic I/R and the associated signaling pathway, we utilized a syngeneic orthotopic liver transplantation rat model to induce hepatic I/R injury.

RESULTS

Pretreatment with Crt significantly mitigated hepatic I/R injury. This was evident by decreased activities of serum ALT, AST and LDH, indicating improved liver function. Crt treatment also alleviated oxidative stress, as demonstrated by decreased serum MDA content and elevated serum SOD and GSH-Px activities. Furthermore, Crt suppressed inflammatory responses by downregulating both the serum and liver IL-1β, IL-6 and TNF-α while upregulating IL-10 expression. Additionally, Crt reduced apoptosis by decreasing pro-apoptotic Bax, cleaved caspase-3 and cleaved caspase-9, while increasing anti-apoptotic Bcl2 expression. Notably, these protective effects of Crt were dose-dependent. Moreover, our data indicates that Crt plays protective functions during hepatic I/R via disrupting Keap1/Nrf2 interaction and activating Nrf2/HO-1 signaling. This was further supported by observations of alleviated hepatic histopathological changes in I/R rats treated with Crt.

CONCLUSIONS

Crt shows potential as a therapeutic agent for preventing hepatic I/R injury during clinical liver transplantation.

An integrated proteomics and metabolomics approach to assess graft quality and predict early allograft dysfunction after liver transplantation: a retrospective cohort study

BACKGROUND

Early allograft dysfunction (EAD) is a common complication after liver transplantation (LT) and is associated with poor prognosis. Graft itself plays a major role in the development of EAD. We aimed to reveal the EAD-specific molecular profiles to assess graft quality and establish EAD predictive models.

METHODS

A total of 223 patients who underwent LT were enrolled and divided into training ( n =73) and validation ( n =150) sets. In the training set, proteomics was performed on graft biopsies, together with metabolomics on paired perfusates. Differential expression, enrichment analysis, and protein-protein interaction network were used to identify the key molecules and pathways involved. EAD predictive models were constructed using machine learning and verified in the validation set.

RESULTS

A total of 335 proteins were differentially expressed between the EAD and non-EAD groups. These proteins were significantly enriched in triglyceride and glycerophospholipid metabolism, neutrophil degranulation, and the MET-related signaling pathway. The top 12 graft proteins involved in the aforementioned processes were identified, including GPAT1, LPIN3, TGFB1, CD59, and SOS1. Moreover, downstream metabolic products, such as lactate dehydrogenase, interleukin-8, triglycerides, and the phosphatidylcholine/phosphorylethanolamine ratio in the paired perfusate displayed a close relationship with the graft proteins. To predict the occurrence of EAD, an integrated model using perfusate metabolic products and clinical parameters showed areas under the curve of 0.915 and 0.833 for the training and validation sets, respectively. It displayed superior predictive efficacy than that of currently existing models, including donor risk index and D-MELD scores.

CONCLUSIONS

We identified novel biomarkers in both grafts and perfusates that could be used to assess graft quality and provide new insights into the etiology of EAD. Herein, we also offer a valid tool for the early prediction of EAD.

Extracellular CIRP promotes Kupffer cell inflammatory polarization in sepsis

Introduction

Sepsis is a life-threatening inflammatory condition caused by dysregulated host responses to infection. Extracellular cold-inducible RNA-binding protein (eCIRP) is a recently discovered damage-associated molecular pattern that causes inflammation and organ injury in sepsis. Kupffer cells can be activated and polarized to the inflammatory M1 phenotype, contributing to tissue damage by producing proinflammatory mediators. We hypothesized that eCIRP promotes Kupffer cell M1 polarization in sepsis.

Methods

We stimulated Kupffer cells isolated from wild-type (WT) and TLR4-/- mice with recombinant mouse (rm) CIRP (i.e., eCIRP) and assessed supernatant IL-6 and TNFα levels by ELISA. The mRNA expression of iNOS and CD206 for M1 and M2 markers, respectively, was assessed by qPCR. We induced sepsis in WT and CIRP-/- mice by cecal ligation and puncture (CLP) and assessed iNOS and CD206 expression in Kupffer cells by flow cytometry.

Results

eCIRP dose- and time-dependently increased IL-6 and TNFα release from WT Kupffer cells. In TLR4-/- Kupffer cells, their increase after eCIRP stimulation was prevented. eCIRP significantly increased iNOS gene expression, while it did not alter CD206 expression in WT Kupffer cells. In TLR4-/- Kupffer cells, however, iNOS expression was significantly decreased compared with WT Kupffer cells after eCIRP stimulation. iNOS expression in Kupffer cells was significantly increased at 20 h after CLP in WT mice. In contrast, Kupffer cell iNOS expression in CIRP-/- mice was significantly decreased compared with WT mice after CLP. CD206 expression in Kupffer cells was not different across all groups. Kupffer cell M1/M2 ratio was significantly increased in WT septic mice, while it was significantly decreased in CIRP-/- mice compared to WT mice after CLP.

Conclusion

Our data have clearly shown that eCIRP induces Kupffer cell M1 polarization via TLR4 pathway in sepsis, resulting in overproduction of inflammatory cytokines. eCIRP could be a promising therapeutic target to attenuate inflammation by preventing Kupffer cell M1 polarization in sepsis.

Quercetin, a natural flavonoid, protects against hepatic ischemia-reperfusion injury via inhibiting Caspase-8/ASC dependent macrophage pyroptosis

INTRODUCTION

Hepatic ischemia-reperfusion injury (IRI) is an inevitable adverse event following liver surgery, leading to liver damage and potential organ failure. Despite advancements, effective interventions for hepatic IRI remain elusive, posing a significant clinical challenge. The innate immune response significantly contributes to the pathogenesis of hepatic IRI by promoting an inflammatory cytotoxic cycle. We have reported that blocking GSDMD-induced pyroptosis in innate immunity cells protected hepatic IRI from inflammatory injury. However, the search for effective pyroptosis inhibitors continues.

OBJECTIVES

This study aims to evaluate whether quercetin, a natural flavonoid, can inhibit GSDMD-induced pyroptosis and mitigate hepatic IRI.

METHODS

We established the hepatic IRI murine model and cellular pyroptosis model to evaluate the efficacy of quercetin.

RESULTS

Quercetin effectively alleviated hepatic IRI-induced tissue necrosis and inflammation. We found that during hepatic IRI, the cleavage of GSDMD occurred in hepatic macrophages, but not in other non-parenchymal cells. Quercetin inhibited the cleavage of GSDMD in macrophages. Moreover, we found that quercetin blocked the ASC assembly to inhibit the formation of NLRP3 inflammasomes and AIM2 inflammasomes, suppressing macrophage pyroptosis. Co-immunoprecipitation experiments confirmed that quercetin inhibited the interaction between ASC and Caspase-8, which is the mechanism of ASC complex and inflammasome formation. Overexpression of Caspase-8 abolished the anti-pyroptosis effect of quercetin in NLRP3 and AIM2 inflammasome signaling. Furthermore, we found that the hepatoprotective activity of quercetin was reduced in myelocytic GSDMD-deficient mice.

CONCLUSION

Our findings suggest that quercetin has beneficial effects on hepatic IRI. Quercetin could attenuate hepatic IRI and target inhibition of macrophage pyroptosis via blocking Caspase-8/ASC interaction. We recommend that quercetin might serve as a targeted approach for the prevention and personalized treatment of hepatic IRI in perioperative patients.

Enhanced external counterpulsation treatment improves multi-organ hemodynamics for postoperative liver transplantation patient. A case report

INTRODUCTION

Post liver transplantation (LT) patients endure high morbidity rate of multi-organ ischemic symptoms following reperfusion. We hypothesize that enhanced external counterpulsation (EECP) as a typical non-invasive assisted circulation procedure, which can efficiently inhibit the relative ischemic symptoms via the systemic improvement of hemodynamics.

CASE PRESENTATION

A 51-year-old male patient, 76 kg, 172 cm, received orthotopic LT surgery for viral hepatitis B induced acute-on-chronic liver failure hepatic failure. His medical records revealed ischemic symptoms in multi-organ at the time of hospital discharge, including headache, refractory insomnia, abdominal paralysis, and lower limb pain. The EECP treatment was introduced for assisted rehabilitation and to improve the postoperative quality of life. Doppler Ultrasound examination showed significant augmentation of blood flow volume in the carotid arteries, the hepatic artery, the portal vein and the femoral artery during EECP intervention. A standard 35-hour EECP treatment led to significant improvement in quality of life, e.g. sleep quality and walking ability.

CONCLUSION

We report a case of multi-organ ischemic symptoms in a post LT patient. EECP treatment can significantly improve the quality of life via the systematic promotion of hemodynamics.

Algorithmic Approach to Deranged Liver Functions After Transplantation

Liver transplant (LT) recipients require close follow-up with regular monitoring of the liver function tests (LFTs). Evaluation of deranged LFT should be individualized depending upon the time since LT, peri-operative events, clinical course, and any complications. These derangements can range from mild and asymptomatic to severe and symptomatic elevations requiring expedited personalized assessment and management. Pattern of LFT derangement (hepatocellular, cholestatic, or mixed), donor-recipient risk factors, timing after LT (post-operative, 1-12 months, and >12 months since LT) along with clinical context and symptomatology are important considerations before proceeding with the initial evaluation. Compliance to immunosuppression and drug interactions should be ascertained along with local epidemiology of infections. Essential initial evaluation must include an ultrasound abdomen with Doppler to rule out any structural causes such as biliary or vascular complications apart from focussed laboratory evaluation. Early allograft dysfunction, ischemia reperfusion injury, small-for-size syndrome, biliary leaks, hepatic artery, and portal vein thrombosis are usual culprits in the early post-operative period whereas viral hepatitis (acute or reactivation), opportunistic infections, and recurrence of the primary disease are more frequent in the later period. Graft rejection, biliary strictures, sepsis, and drug induced liver injury remain possible etiologies at all times points after LT. Initial evaluation algorithm must be customized based on history, clinical examination, risk factors, and pattern and severity of deranged LFT. Allograft rejection is a diagnosis of exclusion and requires liver biopsy to confirm and assess severity. Empirical treatment of rejection sans liver biopsy is discouraged.

Ferroptosis: a new target for hepatic ischemia-reperfusion injury?

Ischemia-reperfusion injury (IRI) can seriously affect graft survival and prognosis and is an unavoidable event during liver transplantation. Ferroptosis is a novel iron-dependent form of cell death characterized by iron accumulation and overwhelming lipid peroxidation; it differs morphologically, genetically, and biochemically from other well-known cell death types (autophagy, necrosis, and apoptosis). Accumulating evidence has shown that ferroptosis is involved in the pathogenesis of hepatic IRI, and targeting ferroptosis may be a promising therapeutic approach. Here, we review the pathways and phenomena involved in ferroptosis, explore the associations and implications of ferroptosis and hepatic IRI, and discuss possible strategies for modulating ferroptosis to alleviate the hepatic IRI.

Anti-apoptotic treatment of warm ischemic male rat livers in machine perfusion improves symptoms of ischemia-reperfusion injury

Background

Liver donation after cardiac death (DCD) makes up a small percentage of the organs used in transplantation and poses a higher risk of graft loss compared to donation after brain death (DBD); this is a result of ischemia reperfusion for which the exact injury mechanisms are currently not fully understood. However, reperfusion injury has been shown to lead to necrosis as well as apoptosis through oxidative stress and mitochondrial dysfunction. In this work, we propose that use of the pro-survival, anti-apoptotic CEPT cocktail in post-ischemia normothermic machine perfusion (NMP) may improve recovery in rat livers subjected to extended durations of warm ischemia.

Materials and Methods

Livers procured from male Lewis rats were subjected to 90 min of warm ischemia, followed by 6 h of NMP where they were treated either with the survival-enhancing anti-apoptotic cocktail (CEPT), the vehicle (DMSO) or the base media with no additives.

Results

The CEPT-treated group exhibited lower expression of hepatic injury biomarkers, and improvement in a range of hepatocellular symptoms associated with the hepatic parenchyma, biliary epithelium and the sinusoidal endothelium, including recovery of bile secretion and lowered vascular resistance.

Conclusions

This study's findings suggest apoptosis plays a more significant role in ischemia-reperfusion injury than previously understood, and provide useful insight for further investigation of the specific underlying mechanisms and development of novel treatment methods.

Bulk and single-cell RNA sequencing analysis with 101 machine learning combinations reveal neutrophil extracellular trap involvement in hepatic ischemia-reperfusion injury and early allograft dysfunction

BACKGROUND

Hepatic ischaemia-reperfusion injury (HIRI) is a major clinical concern during the perioperative period and is closely associated with early allograft dysfunction (EAD), acute rejection (AR) and long-term graft survival. Neutrophil extracellular traps (NETs) are extracellular structures formed by the release of decondensed chromatin and granular proteins following neutrophil stimulation. There is growing evidence that NETs are involved in the progression of various liver transplantation complications, including ischaemia-reperfusion injury (IRI). This study aimed to comprehensively analyse the expression patterns of NET-related genes (NRGs) in HIRI, identify HIRI subtypes with distinct characteristics, and develop a reliable EAD prediction model.

METHODS

Microarray, bulk RNA-seq, and single-cell sequencing datasets were obtained from the GEO database. Initially, differentially expressed NRGs (DE-NRGs) were identified using differential gene expression analyses. We then utilised a non-negative matrix factorisation (NMF) algorithm to classify HIRI samples. Subsequently, we employed machine learning algorithms to screen the hub NRGs related to EAD and developed an EAD prediction model based on these hub NRGs. Concurrently, we assessed the expression patterns of hub NRGs at the single-cell level using the HIRI. Additionally, we validated C5AR1 expression and its effect on HIRI and NETs formation in a rat orthotopic liver transplantation (OLT) model.

RESULTS

In this study, we identified 11 DE-NRGs in the HIRI context. Based on these 11 DE-NRGs, HIRI samples were classified into two distinct clusters. Cluster1 exhibited a low expression of DE-NRGs, minimal neutrophil infiltration, mild inflammation, and a low incidence of EAD. Conversely, Cluster2 displayed the opposite phenotype, with an activated inflammatory subtype and a higher incidence of EAD. Furthermore, an EAD prediction model was developed using the four hub NRGs associated with EAD. Based on risk scores, HIRI samples were classified into high- and low-risk groups. The OLT model confirmed substantial upregulation of C5AR1 expression in the liver tissue, accompanied by increased formation of NETs. Treatment with a C5AR1 antagonist improved liver function, reduced tissue inflammation, and decreased NETs formation.

CONCLUSIONS

This study distinguished two apparent HIRI subtypes, established a predictive model for EAD, and validated the effect of C5AR1 on HIRI. These findings provide novel perspectives for the development of advanced clinical strategies to enhance the outcomes of liver transplant recipients.

NLRP3 Inflammasome in Acute and Chronic Liver Diseases

NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) is an intracellular complex that upon external stimuli or contact with specific ligands, recruits other components, forming the NLRP3 inflammasome. The NLRP3 inflammasome mainly mediates pyroptosis, a highly inflammatory mode of regulated cell death, as well as IL-18 and IL-1β production. Acute and chronic liver diseases are characterized by a massive influx of pro-inflammatory stimuli enriched in reactive oxygen species (ROS) and damage-associated molecular patterns (DAMPs) that promote the assemblage and activation of the NLRP3 inflammasome. As the major cause of inflammatory cytokine storm, the NLRP3 inflammasome exacerbates liver diseases, even though it might exert protective effects in regards to hepatitis C and B virus infection (HCV and HBV). Here, we summarize the current knowledge concerning NLRP3 inflammasome function in both acute and chronic liver disease and in the post liver transplant setting, focusing on the molecular mechanisms involved in NLRP3 activity.

Identification and validation of potential diagnostic signature and immune cell infiltration for HIRI based on cuproptosis-related genes through bioinformatics analysis and machine learning

Background and aims

Cuproptosis has emerged as a significant contributor in the progression of various diseases. This study aimed to assess the potential impact of cuproptosis-related genes (CRGs) on the development of hepatic ischemia and reperfusion injury (HIRI).

Methods

The datasets related to HIRI were sourced from the Gene Expression Omnibus database. The comparative analysis of differential gene expression involving CRGs was performed between HIRI and normal liver samples. Correlation analysis, function enrichment analyses, and protein-protein interactions were employed to understand the interactions and roles of these genes. Machine learning techniques were used to identify hub genes. Additionally, differences in immune cell infiltration between HIRI patients and controls were analyzed. Quantitative real-time PCR and western blotting were used to verify the expression of the hub genes.

Results

Seventy-five HIRI and 80 control samples from three databases were included in the bioinformatics analysis. Three hub CRGs (NLRP3, ATP7B and NFE2L2) were identified using three machine learning models. Diagnostic accuracy was assessed using a receiver operating characteristic (ROC) curve for the hub genes, which yielded an area under the ROC curve (AUC) of 0.832. Remarkably, in the validation datasets GSE15480 and GSE228782, the three hub genes had AUC reached 0.904. Additional analyses, including nomograms, decision curves, and calibration curves, supported their predictive power for diagnosis. Enrichment analyses indicated the involvement of these genes in multiple pathways associated with HIRI progression. Comparative assessments using CIBERSORT and gene set enrichment analysis suggested elevated expression of these hub genes in activated dendritic cells, neutrophils, activated CD4 memory T cells, and activated mast cells in HIRI samples versus controls. A ceRNA network underscored a complex regulatory interplay among genes. The genes mRNA and protein levels were also verified in HIRI-affected mouse liver tissues.

Conclusion

Our findings have provided a comprehensive understanding of the association between cuproptosis and HIRI, establishing a promising diagnostic pattern and identifying latent therapeutic targets for HIRI treatment. Additionally, our study offers novel insights to delve deeper into the underlying mechanisms of HIRI.

The navel nanoethosomal formulation of gamma-oryzanol attenuates testicular ischemia/reperfusion damages

Testicular torsion reduces blood flow to testes and induces tissue ischemia. Antioxidant can have pivotal roles in alleviation of the effects of torsion/reperfusion. Gamma-oryzanol (γ-Oryzanol) has several pharmacological properties such as antioxidant and anti-apoptosis that can be used in this way. This study was conducted to evaluate the effects of nanoethosomal formulation of gamma-oryzanol (γ-Oryzanol-NEs) on testicular damages in a mouse model of ischemia/reperfusion damage. Following induction of ischemia/reperfusion, the mice were treated with γ-Oryzanol and γ-Oryzanol-NEs (6 mg/kg) in times of 3 h and 6 h. The expression of positive cells of TUNEL, superoxide dismutase (SOD), glutathione peroxidase (GPx), heat shock protein-70 (HSP70) and caspase 3 and histopathological parameters were assessed. The results showed higher expression of positive cells of TUNEL, HSP70 and caspase 3 and lower expressions of SOD and GPx in control mice compared with those treated with γ-Oryzanol-NEs (P = 0.001). The treatment with γ-Oryzanol-NEs could decrease pathological damages and the expression of positive cells of TUNEL, HSP70 and caspase 3 and increase the expressions of SOD and GPx. In conclusion, γ-Oryzanol-NEs could have the protective effects on torsion/reperfusion by decreasing apoptosis and increasing antioxidant status in a mouse model.

Calorie restriction mimetic, resveratrol, attenuates hepatic ischemia and reperfusion injury through enhancing efferocytosis of macrophages via AMPK/STAT3/S1PR1 pathway

Calorie restriction (CR) mimetic, resveratrol (RSV), has the capacity of promoting phagocytosis. However, its role in hepatic ischemia and reperfusion injury (HIRI) remains poorly understood. This study aimed to investigate the effect of RSV on alleviating HIRI and explore the underlying mechanisms. RSV was intraperitoneally injected in mice HIRI model, while RSV was co-incubated with culture medium for 24 h in RAW 264.7 cells and kupffer cells. Macrophage efferocytosis was assessed by immunostaining of PI and F4/80. The clearance of apoptotic neutrophils in the liver was determined by immunostaining of Ly6-G and cleaved-caspase-3. HE staining, Suzuki's score, serum levels of ALT, AST, TNF-α and IL-1β were analyzed to evaluate HIRI. The efferocytosis inhibitor, Cytochalasin D, was utilized to investigate the effect of RSV on HIRI. Western blot was employed to measure the levels of AMPKα, phospho-AMPKα, STAT3, phospho-STAT3 and S1PR1. SiSTAT3 and inhibitors targeting AMPK, STAT3 and S1PR1, respectively, were used to confirm the involvement of AMPK/STAT3/S1PR1 pathway in RSV-mediated efferocytosis and HIRI. RSV facilitated the clearance of apoptotic neutrophils and attenuated HIRI, which was impeded by Cytochalasin D. RSV boosted macrophage efferocytosis by up-regulating the levels of phospho-AMPKα, phospho-STAT3 and S1PR1, which was reversed by AMPK, STAT3 and S1PR1 inhibitors, respectively. Inhibition of STAT3 suppressed RSV-induced clearance of apoptotic neutrophils and exacerbated HIRI. CR mimetic, RSV, alleviates HIRI by promoting macrophages efferocytosis through AMPK/STAT3/S1PR1 pathway, providing valuable insights into the mechanisms underlying the protective effects of CR on attenuating HIRI.

A single-chain antibody construct with specificity of a natural IgM antibody reduces hepatic ischemia reperfusion injury in mice

Natural immunoglobulin M (IgM) antibodies have been shown to recognize post-ischemic neoepitopes following reperfusion of tissues and to activate complement. Specifically, IgM antibodies and complement have been shown to drive hepatic ischemia reperfusion injury (IRI). Herein, we investigate the therapeutic effect of C2 scFv (single-chain antibody construct with specificity of a natural IgM antibody) on hepatic IRI in C57BL/6 mice. Compared with PBS-treated mice, C2 scFv-treated mice displayed almost no necrotic areas, significant reduction in serum ALT, AST and LDH levels, and significantly reduced in the number of TUNEL positive cells. Moreover, C2 scFv-treated mice exhibited a notable reduction in inflammatory cells after hepatic IRI than PBS-treated mice. The serum IL-6, IL-1β, TNF-α and MPC-1 levels were also severely suppressed by C2 scFv. Interestingly, C2 scFv reconstituted hepatic inflammation and IRI in Rag1-/- mice. We found that C2 scFv promoted hepatic cell death and increased inflammatory cytokines and infiltration of inflammatory cells after hepatic IRI in Rag1-/- mice. In addition, IgM and complement 3d (C3d) were deposited in WT mice and in Rag1-/- mice reconstituted with C2 scFv, indicating that C2 scFv can affect IgM binding and complement activation and reconstitute hepatic IRI. C3d expression was significantly lower in C57BL/6 mice treated with C2 scFv compared to PBS, indicating that excessive exogenous C2 scFv inhibited complement activation. These data suggest that C2 scFv alleviates hepatic IRI by blocking complement activation, and treatment with C2 scFv may be a promising therapy for hepatic IRI.

Imp7 siRNA nanoparticles protect against mechanical ventilation-associated liver injury by inhibiting HMGB1 production and NETs formation

Mechanical ventilation (MV) has the potential to induce extra-pulmonary organ damage by adversely affecting the lungs and promoting the secretion of inflammatory cytokines. High-mobility group box 1 protein (HMGB1) is a pro-inflammatory mediator in ventilator-induced lung injury (VILI), but its effect on MV-associated liver injury and the mechanisms are poorly understood. In the present study, mice were subjected to high-volume MV (20 ml/kg) to induce VILI. MV-induced HMGB1 prompted neutrophil extracellular traps (NETs) formation and PANoptosis within the liver. Inhibiting NETs formation by DNase I or PAD4 inhibitor, or by HMGB1 neutralizing ameliorated the liver injury. HMGB1 activated neutrophils to form NETs through TLR4/MyD88/TRAF6 pathway. Importantly, Importin7 siRNA nanoparticles inhibited HMGB1 release and protected against MV-associated liver injury. These data provide evidence of MV-induced HMGB1 prompted NETs formation and PANoptosis in the liver via the TLR4/MyD88/TRAF6 pathway. HMGB1 is a potential therapeutic target for MV-associated liver injury.