Liver Ischemia Research Articles

Integrative analysis of the roles of lncRNAs and mRNAs in ischaemic preconditioning to alleviate liver ischaemia–reperfusion injury in mice

The objective of our study was to elucidate the possible underlying mechanism for the protective effect of ischaemic preconditioning (IPC) against ischaemia-reperfusion (I/R) injury and to provide new research perspectives of long non-coding RNAs (lncRNAs). In this study, serum and liver tissue samples were collected to measure indexes of liver injury from a mouse liver model in sham, I/R injury and I/R + IPC groups. Furthermore, liver samples from 5 randomly selected mice per group were extracted and subjected to the microarray and subsequent bioinformatics analysis. IPC ameliorated liver damage by lowered liver transaminase levels and pro-inflammatory cytokines. A total of 167 lncRNAs and 108 messenger RNAs (mRNAs) were significantly differentially expressed genes (DEGs) between the I/R + IPC and I/R groups. Gene Ontology (GO) analysis revealed that these genes were mainly related to unfolded proteins, responses to topologically incorrect proteins, responses to temperature stimuli, protein folding and protein refolding. Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis indicated that the DEGs were enriched in the following pathways: protein processing in the endoplasmic reticulum; antigen processing and presentation; and fructose and mannose metabolism. Additionally, the 7 selected DEGs (Hspa1ab, Chka, Clec2h, Mvd, Adra1a, AK085737 and AK088966) were validated in modules of the lncRNA-mRNA weighted coexpression network, which agreed with the qRT–PCR and chip data. And the identified differentially expressed lncRNAs and mRNAs may provide new clues to understand the pivotal pathophysiological mechanism by which IPC alleviates I/R-caused liver damage.

Ultrasensitive near-infrared fluorescence probe activated by nitroreductase for in vivo hypoxia detection

The fluorescence probe has attracted much attention in the detection of hypoxia-related pathological conditions with unique advantage. However, in vivo imaging the early stages of diseases formation and development remains a great challenge, mainly due to the lack of highly sensitive and specific fluorescence probe. Herein, a high-efficiency near-infrared fluorescence probe YQ-NO2 was synthesized to detect hypoxia via responding to nitroreductase (NTR) in living subjects. In vitro confocal-mediated competitive binding inhibition and flow cytometry analyses indicated YQ-NO2 was of high specificity on hypoxic cells. In vivo near-infrared imaging showed that the probe had the laudable characteristics of a low background inference, fast response and prolonged imaging time in the tumor-bearing mice. Furthermore, it had the property of high affinity and potent permeability, allowing for continuously monitoring cell hypoxia to evaluate longitudinal and dynamic change in the tumor area. Meanwhile, ischemic liver and enteritis sites could be accurately and timely imaged in mice. In addition, it was observed that the fluorescence intensity of the probe in tumor was significantly higher than that in inflammation. The probe has failed to exhibit any bio-toxicity in cells and animals treated with high doses. Ultimately, this near-infrared fluorescence probe will offer an imaging tool for characterizing the hypoxia microenvironment at the tiny lesions in vivo.

Protection of propofol on liver ischemia reperfusion injury by regulating Cyp2b10/ Cyp3a25 pathway

To verify whether propofol alleviates liver ischemia-reperfusion injury (IRI) in mice by regulating Cyp2b10/ Cyp3a25 pathway. The liver I/R injury in vivo and in vitro model was constructed. The serum level of AST, ALT, ALP and ALB was detected using ELISA. The mRNA and protein expression of Cyp2b10 and Cyp3a25 were determined by qRT-PCR and western blot, respectively. The liver cell activity was assessed by MTT assay. The binding between Cyp2b10 and Cyp3a25 was evaluated by online website prediction, CoIP, and cell transfection with Cyp2b10 siRNA and pcDNA3.1-Cyp3a25. The hepatocyte apoptosis was examined using flow cytometry assay. The serum level of AST, ALT, ALP was increased and that of ALB was decreased in liver I/R injury in vivo model. Also, the mRNA and protein expression of Cyp2b10 and Cyp3a25 were enhanced and reduced in liver I/R injury in vivo and vitro model respectively. The liver cell activity was markedly reduced in H/R cell model. However, these changes were all reversed with propofol treatment. Furthermore, Cyp2b10 could directly bind to Cyp3a25 to regulate the H/R-induced hepatocyte apoptosis. Propofol plays an effect of on liver I/R injury by regulating Cyp2b10/ Cyp3a25 pathway.

Mild hypothermia ameliorates hepatic ischemia reperfusion injury by inducing RBM3 expression

Liver ischemia reperfusion injury (IRI) is a serious complication of certain liver surgeries, and it is difficult to prevent. As a potential drug-free treatment, mild hypothermia has been shown to promote positive outcomes in patients with IRI. However, the protective mechanism remains unclear. We established in vivo and in vitro models of hepatic ischemia reperfusion (IR) and mild hypothermia pretreatment. Hepatocytes were transfected with RNA-binding motif protein 3 (RBM3) overexpression plasmids, and IR was performed. Cell, culture medium, blood and tissue samples were collected to assess hepatic injury, oxidative stress, apoptosis and changes in RBM3 expression in the liver. Upregulation of RBM3 expression by mild hypothermia reduced the aminotransferase release, liver tissue injury and mitochondrial injury induced by liver IR. Hepatic IR-induced p38 and c-Jun N-terminal kinase (JNK) signaling pathway activation, oxidative stress injury and apoptosis could be greatly reversed by mild hypothermia. Overexpression of RBM3 mimicked the hepatoprotective effect of mild hypothermia. Mild hypothermia protects the liver from ischemia reperfusion-induced p38 and JNK signaling pathway activation, oxidative stress injury and apoptosis through the upregulation of RBM3 expression.

CCAAT/Enhancer-binding Protein Homologous Protein Promotes ROS-mediated Liver Ischemia and Reperfusion Injury by Inhibiting Mitophagy in Hepatocytes.

Liver ischemia and reperfusion (IR) injury represent a major risk factor in both partial hepatectomy and liver transplantation. CCAAT/enhancer-binding protein homologous protein (CHOP) is a key regulator of cell death, its precise molecular basis in regulating hepatocyte death during liver IR has not been delineated. Hepatocellular CHOP deficient mice were generated by bone marrow chimera models using global CHOP knockout mice. Liver partial warm ischemia model and hypoxia/reoxygenation model of primary hepatocytes were applied. Liver injury and mitophagy-related signaling pathways were investigated. IR-stressed patient liver tissues and serum samples were analyzed as well. Mice with hepatocellular CHOP deficiency exhibited alleviated cell death, decreased reactive oxygen species (ROS) expression, and enhanced mitophagy in hepatocytes after IR, confirmed by in vitro studies of hepatocytes after hypoxia/reoxygenation. Mitochondria ROS scavenge by Mito TEMPO effectively attenuated hepatocyte death and liver IR injury of wild-type mice, whereas no significant effects were observed in hepatocellular CHOP -deficient mice. CHOP depletion upregulated dynamin-related protein 1 and Beclin-1 activation in the mitochondria of hepatocytes leading to enhanced mitophagy. Following IR, increased CHOP expression and impaired mitophagy activation were observed in the livers of patients undergoing hepatectomy. N-acetyl cysteine pretreatment significantly improved the liver function of patients after surgery. IR-induced CHOP activation exacerbates ROS-mediated hepatocyte death by inhibiting dynamin-related protein 1-Beclin-1-dependent mitophagy.

Prolyl Hydroxylase Inhibition Mitigates Allograft Injury During Liver Transplantation.

Ischemia and reperfusion injury (IRI) determines primary allograft function after liver transplantation (LT). Primary graft dysfunction (PGD) is associated with increased morbidity and impaired graft survival and can eventually progress to graft failure requiring retransplantation. Hypoxia-inducible transcription factor-prolyl hydroxylase containing enzymes (PHD1, PHD2, and PHD3) are molecular oxygen sensors, which control the adaptive hypoxia response through the hypoxia-inducible factor (HIF). In this study, we have investigated pharmacological activation of the HIF pathway through inhibition of PHDs as a strategy to reduce PGD after LT. Primary rat hepatocytes were isolated and the impact of the pan-PHD small-molecule inhibitor ethyl-3,4-dihydroxybenzoate (EDHB) on HIF-1 and its downstream target gene expression assessed. Subsequently, various rodent models of segmental warm liver ischemia and reperfusion and orthotopic LT were applied to study the impact of EDHB on normothermic or combined cold and warm liver IRI. Liver enzyme levels and histology were analyzed to quantify hepatic IRI. In vitro, EDHB induced HIF-1 signaling and significantly upregulated its downstream target heme-oxygenase 1 in primary rat hepatocytes. In vivo, after establishment of the optimal EDHB pretreatment conditions in a murine IRI model, EDHB pretreatment significantly mitigated hepatic IRI after warm segmental liver ischemia and reperfusion and allograft injury after orthotopic LT in rats. Mechanistically, EDHB stabilized HIF-1 in the liver and subsequently increased hepatoprotective heme-oxygenase 1 levels, which correlated with reduced hepatic IRI in these models. This proof-of-concept study establishes a strong therapeutic rationale for targeting PHDs with small-molecule inhibitors to mitigate PGD after LT.

Hepatoprotective Role of Carvedilol against Ischemic Hepatitis Associated with Acute Heart Failure via Targeting miRNA-17 and Mitochondrial Dynamics-Related Proteins: An In Vivo and In Silico Study.

Acute heart failure (AHF) is one of the most common diseases in old age that can lead to mortality. Systemic hypoperfusion is associated with hepatic ischemia–reperfusion injury, which may be irreversible. Ischemic hepatitis due to AHF has been linked to the pathogenesis of liver damage. In the present study, we extensively investigated the role of mitochondrial dynamics-related proteins and their epigenetic regulation in ischemic liver injury following AHF and explored the possible hepatoprotective role of carvedilol. The biochemical analysis revealed that the ischemic liver injury following AHF significantly elevated the activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) enzymes, the level of total and direct bilirubin, and the expression of hepatic mitogen-activated protein kinase (MAPK), dynamin-1-like protein (DNM1L), and hepatic miRNA-17. At the same time, it significantly reduced the serum albumin level, the activity of hepatic superoxide dismutase (SOD), and the expression of mitochondrial peroxisome proliferator-activated receptor-1α (PGC-1α), and mitofusin 2 (Mtf2). The histological examination of the liver tissue revealed degenerated hepatocytes. Interestingly, administration of carvedilol either prior to or after isoprenaline-induced AHF significantly improved the liver function and reversed the deterioration effect of AHF-induced ischemic hepatitis, as demonstrated by biochemical, immunohistochemical, and histological analysis. Our results indicated that the hepatoprotective effect of carvedilol in ameliorating hepatic ischemic damage could be attributed to its ability to target the mitochondrial dynamics-related proteins (Mtf2, DNM1L and PGC-1α), but also their epigenetic regulator miRNA-17. To further explore the mode of action of carvedilol, we have investigated, in silico, the ability of carvedilol to target dynamin-1-like protein and mitochondrial dynamics protein (MID51). Our results revealed that carvedilol has a high binding affinity (−14.83 kcal/mol) toward the binding pocket of DNM1L protein. In conclusion, our study highlights the hepatoprotective pharmacological application of carvedilol to attenuate ischemic hepatitis associated with AHF.

The Role of Neutrophils as a Driver in Hepatic Ischemia-Reperfusion Injury and Cancer Growth.

The innate immune system plays an essential role in the response to sterile inflammation and its association with liver ischemia and reperfusion injury (IRI). Liver IRI often manifests during times of surgical stress such as cancer surgery or liver transplantation. Following the initiation of liver IRI, stressed hepatocytes release damage-associated molecular patterns (DAMPs) which promote the infiltration of innate immune cells which then initiate an inflammatory cascade and cytokine storm. Upon reperfusion, neutrophils are among the first cells that infiltrate the liver. Within the liver, neutrophils play an important role in fueling tissue damage and tumor progression by promoting the metastatic cascade through the formation of Neutrophil Extracellular Traps (NETs). NETs are composed of web-like DNA structures containing proteins that are released in response to inflammatory stimuli in the environment. Additionally, NETs can aid in mediating liver IRI, promoting tumor progression, and most recently, in mediating early graft rejection in liver transplantation. In this review we aim to summarize the current knowledge of innate immune cells, with a focus on neutrophils, and their role in mediating IRI in mouse and human diseases, including cancer and transplantation. Moreover, we will investigate the interaction of Neutrophils with varying subtypes of other cells. Furthermore, we will discuss the role and different treatment modalities in targeting Neutrophils and NETs to prevent IRI.

Nitric Oxide Modulation as a Potential Molecular Mechanism Underlying the Protective Role of NaHS in Liver Ischemia Reperfusion Injury.

Liver IR is a frequent clinical complication with high morbidity and mortality. The present study evaluated the possible protective effect of sodium hydrosulfide (NaHS), a H2S donor, in IR-induced hepatic injury and explored the mechanisms of actions of the investigated drug. Male albino rats (200-230 g) were divided into the following groups: group 1:Sham-operated non treated rats, group 2: IR non treated rats, group 3: L-NNA + IR rats, group 4: NaHS + IR rats, group 5: L-NNA + NaHS + IR rats. Blood samples were collected for ALT determination. Liver tissue samples were used for the assessment of GPx, catalase, SOD, MDA, total nitrites and TNF- α. Parts from the liver were fixed in 10% formalin solution for histopathological examination and immunohistochemical examination of iNOS, eNOS and caspase-3. NaHS protected the liver against IR. This hepatoprotection was associated with normalization of antioxidant enzyme activity and decrease in hepatic MDA, TNF-α and expression of caspase- 3 and iNOS. NaHS is hepatoprotective in IR injury. The hepatoprotective effects of NaHS are associated with antioxidant, anti-inflammatory and antiapoptotic effects. These effects are probably mediated via NO modulation.

A bioartificial transgenic porcine whole liver expressing human proteins alleviates acute liver failure in pigs

BackgroundPreventing heterologous protein influx in patients is important when using xenogeneic bioartificial livers (BALs) to treat liver failure. The development of transgenic porcine livers synthesizing human proteins is a promising approach in this regard. Here, we evaluated the safety and efficacy of a transgenic porcine liver synthesizing human albumin (hALB) and coagulation factor VII (hFVII) within a bioartificial system. MethodsTibetan miniature pigs were randomly subjected to different interventions after surgery-induced partially ischemic liver failure. Group A (n = 4) was subjected to basic treatment; group B (n = 4) was to standard medical treatment and wild-type porcine BAL perfusion, and group C (n = 2) was to standard medical treatment and transgenic BAL perfusion. Biochemical parameters, coagulation status, survival time, and pathological changes were determined. Expressions of hALB and hFVII were detected using immunohistochemistry and enzyme-linked immunosorbent assays. ResultsThe survival time in group A was 9.75 ± 1.26 days; this was shorter than that in both perfused groups, in which all animals reached an endpoint of 12 days (P = 0.006). Ammonia, bilirubin, and lactate levels were significantly decreased, whereas albumin and fibrinogen levels were increased after perfusion (all P < 0.05). hALB and hFVII were detected in transgenic BAL-perfused pig serum and ex vivo in the liver tissues. ConclusionsThe humanized transgenic pig livers could synthesize and secrete hALB and hFVII ex vivo in a whole organ-based bioartificial system, while maintaining their metabolism, detoxification, transformation, and excretion functions, which were comparable to those observed in wild-type porcine livers. Therefore, the use of transgenic bioartificial whole livers is expected to become a new approach in treating acute liver failure.

The Importance of CXCL1 in the Physiological State and in Noncancer Diseases of the Oral Cavity and Abdominal Organs.

CXCL1 is a CXC chemokine, CXCR2 ligand and chemotactic factor for neutrophils. In this paper, we present a review of the role of the chemokine CXCL1 in physiology and in selected major non-cancer diseases of the oral cavity and abdominal organs (gingiva, salivary glands, stomach, liver, pancreas, intestines, and kidneys). We focus on the importance of CXCL1 on implantation and placentation as well as on human pluripotent stem cells. We also show the significance of CXCL1 in selected diseases of the abdominal organs, including the gastrointestinal tract and oral cavity (periodontal diseases, periodontitis, Sjögren syndrome, Helicobacter pylori infection, diabetes, liver cirrhosis, alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), HBV and HCV infection, liver ischemia and reperfusion injury, inflammatory bowel disease (Crohn’s disease and ulcerative colitis), obesity and overweight, kidney transplantation and ischemic-reperfusion injury, endometriosis and adenomyosis).

Aging deteriorated liver Ischemia and reperfusion injury by suppressing Tribble’s proteins 1 mediated macrophage polarization

ABSTRACT Aggravated liver injury has been reported in aged ischemia/reperfusion-stressed livers; however, the mechanism of aged macrophage inflammatory regulation is not well understood. Here, we found that the adaptor protein TRIB1 plays a critical role in the differentiation of macrophages and the inflammatory response in the liver after ischemia/reperfusion injury. In the present study, we determined that aging promoted macrophage-mediated liver injury and that inflammation was mainly responsible for lower M2 polarization in liver transplantation-exposed humans post I/R. Young and aged mice were subjected to hepatic I/R modeling and showed that aging aggravated liver injury and suppressed macrophage TRIB1 protein expression and anti-inflammatory function in I/R‐stressed livers. Restoration of TRIB1 is mediated by lentiviral infection-induced macrophage anti-inflammatory M2 polarization and alleviated hepatic I/R injury. Moreover, TRIB1 overexpression in macrophages facilitates M2 polarization and anti-inflammation by activating MEK1-ERK1/2 signaling under IL-4 stimulation. Taken together, our results demonstrated that aging promoted hepatic I/R injury by suppressing TRIB1-mediated MEK1-induced macrophage M2 polarization and anti-inflammatory function.

Protective effect of remote liver ischemic postconditioning on pulmonary ischemia and reperfusion injury in diabetic and non-diabetic rats.

Pulmonary ischemia and reperfusion (I/R) injury occurs in many clinical conditions and causes severe damage to the lungs. Diabetes mellitus (DM) predisposes to pulmonary I/R injury. We previously found that remote liver ischemia preconditioning protected lungs against pulmonary I/R injury. The aim of the present study was to investigate whether remote liver ischemic postconditioning (RLIPost) attenuates pulmonary damage induced by I/R injury in non-diabetic or diabetic rats. Male Sprague-Dawley rats were assigned into non-diabetic and diabetic groups. All rats except for the sham were exposed to 45 min of left hilum occlusion followed by 2 h of reperfusion. RLIPost was conducted at the onset of pulmonary reperfusion by four cycles of 5 min of liver ischemia and reperfusion. Lung injury was assessed by the wet/dry weight ratio, pulmonary oxygenation, histopathological changes, apoptosis and the expression of inflammatory cytokines. Reperfusion-associated protein phosphorylation states were determined. RLIPost offered strong pulmonary-protection in both non-diabetic and diabetic rats, as reflected in reduced water content and pulmonary structural damage, recovery of lung function, inhibition of apoptosis and inflammation after ischemia-reperfusion. RLIPost induced the activation of pulmonary STAT-3, a key component in the SAFE pathway, but not activation of the proteins in the RISK pathway, in non-diabetic rats. In contrast, RLIPost-induced pulmonary protection in diabetic lungs was independent of SAFE or RISK pathway activation. These results demonstrate that RLIPost exerts pulmonary protection against I/R-induced lung injury in non-diabetic and diabetic rats. The underlying mechanism for protection may be different in non-diabetic (STAT-3 dependent) versus diabetic (STAT-3 independent) rats.

Roles and Mechanisms of Regulated Necrosis in Corneal Diseases: Progress and Perspectives.

Regulated necrosis is defined as cell death characterized by loss of the cell membrane integrity and release of the cytoplasmic content. It contributes to the development and progression of some diseases, including ischemic stroke injury, liver diseases, hypertension, and cancer. Various forms of regulated necrosis, particularly pyroptosis, necroptosis, and ferroptosis, have been implicated in the pathogenesis of corneal disease. Regulated necrosis of corneal cells enhances inflammatory reactions in the adjacent corneal tissues, leading to recurrence and aggravation of corneal disease. In this review, we summarize the molecular mechanisms of pyroptosis, necroptosis, and ferroptosis in corneal diseases and discuss the roles of regulated necrosis in inflammation regulation, tissue repair, and corneal disease outcomes.

Liver Graft Hypothermic Static and Oxygenated Perfusion (HOPE) Strategies: A Mitochondrial Crossroads.

Marginal liver grafts, such as steatotic livers and those from cardiac death donors, are highly vulnerable to ischemia–reperfusion injury that occurs in the complex route of the graft from “harvest to revascularization”. Recently, several preservation methods have been developed to preserve liver grafts based on hypothermic static preservation and hypothermic oxygenated perfusion (HOPE) strategies, either combined or alone. However, their effects on mitochondrial functions and their relevance have not yet been fully investigated, especially if different preservation solutions/effluents are used. Ischemic liver graft damage is caused by oxygen deprivation conditions during cold storage that provoke alterations in mitochondrial integrity and function and energy metabolism breakdown. This review deals with the relevance of mitochondrial machinery in cold static preservation and how the mitochondrial respiration function through the accumulation of succinate at the end of cold ischemia is modulated by different preservation solutions such as IGL-2, HTK, and UW (gold-standard reference). IGL-2 increases mitochondrial integrity and function (ALDH2) when compared to UW and HTK. This mitochondrial protection by IGL-2 also extends to protective HOPE strategies when used as an effluent instead of Belzer MP. The transient oxygenation in HOPE sustains the mitochondrial machinery at basal levels and prevents, in part, the accumulation of energy metabolites such as succinate in contrast to those that occur in cold static preservation conditions. Additionally, several additives for combating oxygen deprivation and graft energy metabolism breakdown during hypothermic static preservation such as oxygen carriers, ozone, AMPK inducers, and mitochondrial UCP2 inhibitors, and whether they are or not to be combined with HOPE, are presented and discussed. Finally, we affirm that IGL-2 solution is suitable for protecting graft mitochondrial machinery and simplifying the complex logistics in clinical transplantation where traditional (static preservation) and innovative (HOPE) strategies may be combined. New mitochondrial markers are presented and discussed. The final goal is to take advantage of marginal livers to increase the pool of suitable organs and thereby shorten patient waiting lists at transplantation clinics.

Liver Ischemia and Reperfusion Induce Periportal Expression of Necroptosis Executor pMLKL Which Is Associated With Early Allograft Dysfunction After Transplantation.

BackgroundEarly allograft dysfunction (EAD) following liver transplantation (LT) remains a major threat to the survival of liver grafts and recipients. In animal models, it is shown that hepatic ischemia-reperfusion injury (IRI) triggers phosphorylation of Mixed Lineage Kinase domain-like protein (pMLKL) inducing necroptotic cell death. However, the clinical implication of pMLKL-mediated cell death in human hepatic IRI remains largely unexplored. In this study, we aimed to investigate the expression of pMLKL in human liver grafts and its association with EAD after LT.MethodsThe expression of pMLKL was determined by immunohistochemistry in liver biopsies obtained from both human and rat LT. Human liver biopsies were obtained at the end of preservation (T0) and ~1 hour after reperfusion (T1). The positivity of pMLKL was quantified electronically and compared in rat and human livers and post-LT outcomes. Multiplex immunofluorescence staining was performed to characterize the pMLKL-expressing cells.ResultsIn the rat LT model, significant pMLKL expression was observed in livers after IRI as compared to livers of sham-operation animals. Similarly, the pMLKL score was highest after IRI in human liver grafts (in T1 biopsies). Both in rats and humans, the pMLKL expression is mostly observed in the portal triads. In grafts who developed EAD after LT (n=24), the pMLKL score at T1 was significantly higher as compared to non-EAD grafts (n=40). ROC curve revealed a high predictive value of pMLKL score at T1 (AUC 0.70) and the ratio of pMLKL score at T1 and T0 (pMLKL-index, AUC 0.82) for EAD. Liver grafts with a high pMLKL index (>1.64) had significantly higher levels of serum ALT, AST, and LDH 24 hours after LT compared to grafts with a low pMLKL index. Multivariate logistical regression analysis identified the pMLKL-index (Odds ratio=1.3, 95% CI 1.1-1.7) as a predictor of EAD development. Immunohistochemistry on serial sections and multiplex staining identified the periportal pMLKL-positive cells as portal fibroblasts, fibrocytes, and a minority of cholangiocytes.ConclusionPeriportal pMLKL expression increased significantly after IRI in both rat and human LT. The histological score of pMLKL is predictive of post-transplant EAD and is associated with early liver injury after LT. Periportal non-parenchymal cells (i.e. fibroblasts) appear most susceptible to pMLKL-mediated cell death during hepatic IRI.

Antibiotic pretreatment attenuates liver ischemia–reperfusion injury by Farnesoid X receptor activation

Prophylactic antibiotics (Abx) are used before liver surgery, and the influence of antibiotic pretreatment on hepatic ischemia–reperfusion injury (IRI) remains unclear. Hence, we explored the impact of Abx pretreatment on hepatic IRI in the present work. The gut microbiota has an essential role in hepatic bile acid (BA) metabolism, and we assumed that depletion of the gut microbiota could affect the composition of hepatic BAs and affect liver IRI. The IRI model demonstrated that Abx pretreatment attenuated liver IRI by alleviating cell apoptosis, reducing the inflammatory response, and decreasing the recruitment of CCR2+ monocytes. Mechanistically, Abx pretreatment reshaped the gut microbiota, especially decreasing the relative abundance of Firmicutes and increasing the relative abundance of Clostridium, which were related to the transformation of BAs and were consistent with the altered bile acid species (unconjugated BAs, especially UDCA). These altered BAs are known FXR agonists and lead to the activation of the farnesoid X receptor (FXR), which can directly bind to the FXR response element (FXRE) harbored in the TLR4 promoter and further suppress downstream mitogen-activated protein kinase (MAPK) and nuclear kappa B (NF-κB) pathways. Meanwhile, the CCL2–CCR2 axis was also involved in the process of FXR activation, as we confirmed both in vivo and in vitro. Importantly, we proved the importance of FXR in mice and clinical occlusion samples, which were inversely correlated with liver injury. Taken together, our study identified that Abx pretreatment before liver resection was a beneficial event by activating FXR, which might become a potential therapeutic target in treating liver injury.

Diagnostic value of a liver biopsy in patients with an acute liver failure or acute liver injury.

The diagnostic value of liver biopsy in patients with acute liver injury or acute liver failure (ALI/ALF) was investigated. Data from the initial event and follow-up visits were retrospectively analyzed in all patients with a liver biopsy during ALI/ALF from January 2010 to May 2020 at the University Hospital Frankfurt, Germany. The cohort comprised 66 patients. Post-biopsy hemorrhage occurred in 2 of 66 but was self-limited. In five patients suspected liver involvement by a systemic extrahepatic disease was confirmed and excluded in eight patients. In 4 of 66 patients, the etiology of ALI/ALF remained unknown. Liver biopsy hinted at the etiology of ALI/ALF in 2 of 6 patients with rare diagnoses (hemophagocytic lymphohistiocytosis: 2 of 66; ischemic liver injury: 1 of 66, ALI/ALF due to a systemic infection: 3 of 66). In 31 of 34 patients with drug-induced liver injury (DILI), histopathology suggested DILI; in further 2 patients, DILI was among the differential diagnoses. However, DILI was also the histopathologically preferred diagnosis in 12 of 15 patients with autoimmune hepatitis (AIH). Only in 3 of 15 patients, histopathology was considered compatible with AIH. Serum immunoglobulin G (IgG) and autoantibodies during ALI/ALF were higher in patients with AIH than with DILI. Patients with AIH did not show a more pronounced biochemical response to corticosteroids in the first 10 days of treatment than patients with DILI. Liver biopsy is indispensable when liver involvement by an extrahepatic disease is suspected. To distinguish AIH from DILI in ALI/ALF, serum IgG, and autoantibodies seem more helpful than liver biopsy; long-term follow-up is needed in these patients.

Propionic Acid, Induced in Gut by an Inulin Diet, Suppresses Inflammation and Ameliorates Liver Ischemia and Reperfusion Injury in Mice.

Liver ischemia and reperfusion injury (IRI) is one of the obstacles in liver surgery such as liver resection and transplantation. In this study, we investigated the preventive effect on mouse liver IRI by feeding mice with inulin, which is a heterogeneous blend of indigestible fructose polymer. Mice were fed either a control ordinary diet (CD) or an inulin diet (ID) containing 5% inulin in the CD, for 14 days before the ischemia and reperfusion (IR) maneuver. IR induced-liver damages were significantly ameliorated in the ID group, compared with those in the CD group. Feeding mice with an ID, but not a CD, elevated levels of Bacteroidetes among gut microbiota, and especially increased Bacteroides acidifaciens in mouse feces, which resulted in significant elevation of short-chain fatty acids (SCFAs) in the portal vein of mice. Among SCFAs, propionic acid (PA) was most significantly increased. The microbial gene functions related to PA biosynthesis were much higher in the fecal microbiome of the ID group compared to the CD. However, the action of PA on liver IRI has not been yet clarified. Direct intraperitoneal administration of PA alone prior to the ischemia strongly suppressed liver cell damages as well as inflammatory responses caused by liver IR. Furthermore, PA suppressed the secretion of inflammatory cytokines from peritoneal macrophages stimulated in vitro through TLR-4 with high-mobility group box 1 protein (HMGB-1), known to be released from apoptotic liver cells during the IR insult. The present study shows that PA may play a key role in the inulin-induced amelioration of mouse liver IRI.

Protective effect of remote ischemic postconditioning in rat testes after testicular torsion/detorsion.

Testicular torsion/detorsion can lead to severe testicular damage. The organ-protective effect of remote ischemic postconditioning (RLIPost) against ischemia/reperfusion injury has been characterized; however, it remains unknown whether RLIPost has a testicular protective effect. Here, we tested the hypothesis that RLIPost can protect the testes in a rat model of testicular torsion/detorsion in vivo. Male Sprague-Dawley rats were assigned to sham-operated, control, or remote liver and limb ischemic postconditioning-treated groups. Testicular torsion/detorsion was performed by 3h of testicular torsion (720° clockwise unilateral spermatic cord torsion), followed by 3h of detorsion. For liver and limb ischemic postconditioning, four cycles of 5 min of liver or limb ischemia with 5-min intermittent reperfusion stimuli were conducted at the onset of testicular reperfusion. Liver and limb ischemic postconditioning significantly ameliorated ipsilateral and contralateral testicular swelling responses, preserved morphological integrity and spermatogenesis and inhibited testicular apoptosis. In addition, RLIPost enhanced the phosphorylation of AKT/ERK1/2/GSK-3β/STAT-3 in the ipsilateral testis while suppressing JNK activation in the ipsilateral and contralateral testes. To the best of our knowledge, this study is the first to demonstrate the involvement of RLIPost in an animal model of testicular torsion/detorsion. We showed that RLIPost protects both ipsilateral and contralateral testes against testicular torsion/detorsion in vivo, via at least in part, the RISK and SAFE-mediated signaling pathways.