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ObjectiveLiver injury impacts hepatic inflammation in part via Toll-like receptor (TLR) signalling. Triggering receptor expressed on myeloid cells 2 (TREM-2) modulates TLR4-mediated inflammation in bone marrow (BM)-derived macrophages but its function in liver injury is unknown. Here we hypothesised that the anti-inflammatory effects of TREM-2 on TLR signalling may limit hepatic injury.DesignTREM-2 expression was analysed in livers of humans with various forms of liver injury compared with control individuals. Acute and chronic liver injury models were performed in wild type and Trem-2-/- mice. Primary liver cells from both genotypes of mice were isolated for in vitro experiments.ResultsTREM-2 was expressed on non-parenchymal hepatic cells and induced during liver injury in mice and man. Mice lacking TREM-2 exhibited heightened liver damage and inflammation during acute and repetitive carbon tetrachloride and acetaminophen (APAP) intoxication, the latter of which TREM-2 deficiency was remarkably associated with worsened survival. Liver damage in Trem-2-/- mice following chronic injury and APAP challenge was associated with elevated hepatic lipid peroxidation and macrophage content. BM transplantation experiments and cellular reactive oxygen species assays revealed effects of TREM-2 in the context of chronic injury depended on both immune and resident TREM-2 expression. Consistent with effects of TREM-2 on inflammation-associated injury, primary hepatic macrophages and hepatic stellate cells lacking TREM-2 exhibited augmented TLR4-driven proinflammatory responses.ConclusionOur data indicate that by acting as a natural brake on inflammation during hepatocellular injury, TREM-2 is a critical regulator of diverse types of hepatotoxic injury.

ObjectiveTGF-β2 (TGF-β, transforming growth factor beta), the less-investigated sibling of TGF-β1, is deregulated in rodent and human liver diseases. Former data from bile duct ligated and MDR2 knockout (KO) mouse models for human cholestatic liver disease suggested an involvement of TGF-β2 in biliary-derived liver diseases.DesignAs we also found upregulated TGFB2 in liver tissue of patients with primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), we now fathomed the positive prospects of targeting TGF-β2 in early stage biliary liver disease using the MDR2-KO mice. Specifically, the influence of TgfB2 silencing on the fibrotic and inflammatory niche was analysed on molecular, cellular and tissue levels.Results TgfB2-induced expression of fibrotic genes in cholangiocytes and hepatic stellate cellswas detected. TgfB2 expression in MDR2-KO mice was blunted using TgfB2-directed antisense oligonucleotides (AON). Upon AON treatment, reduced collagen deposition, hydroxyproline content and αSMA expression as well as induced PparG expression reflected a significant reduction of fibrogenesis without adverse effects on healthy livers. Expression analyses of fibrotic and inflammatory genes revealed AON-specific regulatory effects on Ccl3, Ccl4, Ccl5, Mki67 and Notch3 expression. Further, AON treatment of MDR2-KO mice increased tissue infiltration by F4/80-positive cells including eosinophils, whereas the number of CD45-positive inflammatory cells decreased. In line, TGFB2 and CD45 expression correlated positively in PSC/PBC patients and localised in similar areas of the diseased liver tissue.ConclusionsTaken together, our data suggest a new mechanistic explanation for amelioration of fibrogenesis by TGF-β2 silencing and provide a direct rationale for TGF-β2-directed drug development.

Objectives: To study the different cellular death mechanisms between viral cirrhosis and alcoholic cirrhosis. The research investigated autophagy and apoptosis mechanisms in hepatitis B virus (HBV), hepatitis C virus (HCV) and alcohol-induced cirrhosis. Methods: The research team analyzed biopsy samples from the liver which were obtained at Florence Nightingale Hospitals, Istanbul, Turkey. The experimental protocols were performed between February 2021 and February 2023. The study included 19 HBV, 15 HCV, 13 alcohol-related cirrhosis patients and 6 normal liver tissues. Beclin-1, Caspase-3, Bcl-2 and LC3 expressions were evaluated by immunohistochemistry. Results: Staining intensity as well as extent underwent evaluation through H-score methodology. The expression levels of Beclin-1 (control: 0.7[+ or -]0.3, HBV: 6.0[+ or -]1.4, HCV: 5.1[+ or -]1.3, alcohol: 4.8[+ or -]1.2), caspase-3 (control: 0.4[+ or -]0.2, HBV: 6.0[+ or -]1.4, HCV: 5.1[+ or -]1.2, alcohol: 5.5[+ or -]1.3) and Bcl-2 (control: 0.3[+ or -]0.2, HBV: 5.5[+ or -]1.2, HCV: 4.8[+ or -]1.1, alcohol: 4.6[+ or -]1.1) were significantly higher than those of the control group (p <0.001). LC3 expression revealed no between-group differences. A positive association for Beclin-1 with Caspase-3 (r=0.582) alongside negative association for Bcl-2 with Caspase-3 (r=-0.608) was documented. Conclusion: Our findings suggest that both autophagic and apoptotic pathways are active in the pathogenesis of cirrhosis. Similar cell death mechanisms were found to be involved in viral and alcoholic cirrhosis, but these pathways were more prominently activated in viral cirrhosis. Keywords: acute-on-chronicliver failure, cirrhosispathogenesis, autophagymechanisms, apoptosis in liver disease, immunohistochemistry in hepatology

Both transient elastography (TE)-based and non-TE-based criteria exist for detection of varices needing treatment (VNT) in patients with asymptomatic advanced chronic liver disease (CLD). However, their performance in clinical settings at different risk thresholds of detection of VNT and in regions where elastography is not widely available is unknown. We aimed to validate existing noninvasive criteria in our patients with CLD and identify best TE- and non-TE-based criteria for VNT screening at usual risk thresholds. Patients with compensated advanced CLD (cACLD) who underwent esophagogastroduodenoscopy and TE within 3 months were included. Diagnostic performance of Baveno VI, expanded Baveno VI, platelet-model for end-stage liver disease, and platelet-albumin (Rete Sicilia Selezione Terapia-hepatitis C virus) criteria were estimated. Decision curve analysis was conducted for different predictors across range of threshold probabilities. A repeat analysis including all patients with compensated CLD (cACLD and non-cACLD) was performed to simulate absence of TE. A total of 1,657 patients (cACLD, 895; non-cACLD, 762) related to hepatitis B virus (38.2%), hepatitis C virus (33.4%), nonalcoholic steatohepatitis (14.7%), and alcohol (11.8%) were included. Baveno VI identified maximum VNT (97.3%) and had best negative predictive value (96.9%), followed by platelet-albumin criteria. Expanded Baveno VI and platelet-model for end-stage liver disease had intermediate performance. At threshold probability of 5%, Baveno VI criteria showed maximum net benefit, and platelet-albumin criteria was next best, with need for 95 additional elastographies to detect 1 additional VNT. Similar results were obtained on including all patients with compensated CLD irrespective of TE. Baveno VI criteria maximizes VNT yield at 5% threshold probability. An acceptable alternative is the platelet-albumin criteria in resource-limited settings.

Hepatic stellate cell (HSC) activation on liver injury facilitates fibrosis. Hepatokines affecting HSCs are largely unknown. Here we show that hepcidin inhibits HSC activation and ameliorates liver fibrosis. We observe that hepcidin levels are inversely correlated with exacerbation of fibrosis in patients, and also confirm the relationship in animal models. Adenoviral delivery of hepcidin to mice attenuates liver fibrosis induced by CCl 4 treatment or bile duct ligation. In cell-based assays, either hepcidin from hepatocytes or exogenous hepcidin suppresses HSC activation by inhibiting TGFβ1-mediated Smad3 phosphorylation via Akt. In activated HSCs, ferroportin is upregulated, which can be prevented by hepcidin treatment. Similarly, ferroportin knockdown in HSCs prohibits TGFβ1-inducible Smad3 phosphorylation and increases Akt phosphorylation, whereas ferroportin over-expression has the opposite effect. HSC-specific ferroportin deletion also ameliorates liver fibrosis. In summary, hepcidin suppresses liver fibrosis by impeding TGFβ1-induced Smad3 phosphorylation in HSCs, which depends on Akt activated by a deficiency of ferroportin. The peptide hormone hepcidin is released from hepatocytes and regulates iron homoeostasis. Here, the authors show that hepcidin also regulates the activation of hepatic stellate cells (HSCs) in mouse models of liver fibrosis by reducing ferroportin expression and inhibiting the HSC response to TGFβ.

ObjectiveThe death rate of mature hepatocytes is chronically increased in various liver diseases, triggering responses that prevent liver atrophy, but often cause fibrosis. Mice with targeted disruption of inhibitor kappa B kinase (Ikk) in hepatocytes (∆HEP mice) provide a model to investigate this process because inhibiting Ikk–nuclear factor-κB (NF-κB) signalling in hepatocytes increases their apoptosis.MethodsCell proliferation, apoptosis, progenitors, fibrosis and production of Hedgehog (Hh) ligands (progenitor and myofibroblast growth factors) were compared in ∆HEP and control mice before and after feeding methionine choline-deficient ethionine-supplemented (MCDE) diets. Ikkβ was deleted from primary hepatocytes to determine the effects on Hh ligand production; Hh signalling was inhibited directly in progenitors to determine the effects on viability. Liver sections from patients were examined to assess relationships between hepatocyte production of Hh ligands, accumulation of myofibroblastic cells and liver fibrosis.ResultsDisrupting the Ikk–NF-κB pathway in hepatocytes inhibited their proliferation but induced their production of Hh ligands. The latter provided viability signals for progenitors and myofibroblasts, enhancing accumulation of these cell types and causing fibrogenesis. Findings in the mouse models were recapitulated in diseased human livers.ConclusionDying mature hepatocytes produce Hh ligands which promote the compensatory outgrowth of progenitors and myofibroblasts. These results help to explain why diseases that chronically increase hepatocyte death promote cirrhosis.

Although macrophages are recognized as important players in the pathogenesis of chronic liver diseases, their roles in cholestatic liver fibrosis remain incompletely understood. We previously reported that long noncoding RNA-H19 (lncRNA-H19) contributes to cholangiocyte proliferation and cholestatic liver fibrosis of biliary atresia (BA). We here show that monocyte/macrophage CD11B mRNA levels are increased significantly in livers of BA patients and positively correlated with the progression of liver inflammation and fibrosis. The macrophages increasingly infiltrate and accumulate in the fibrotic niche and peribiliary areas in livers of BA patients. Selective depletion of macrophages using the transgenic CD11b-diphtheria toxin receptor (CD11b-DTR) mice halts bile duct ligation (BDL)-induced progression of liver damage and fibrosis. Meanwhile, macrophage depletion significantly reduces the BDL-induced hepatic lncRNA-H19. Overexpression of H19 in livers using adeno-associated virus serotype 9 (AAV9) counteracts the effects of macrophage depletion on liver fibrosis and cholangiocyte proliferation. Additionally, both H19 knockout (H19 −/− ) and conditional deletion of H19 in macrophage (H19 ΔCD11B ) significantly depress the macrophage polarization and recruitment. lncRNA-H19 overexpressed in THP-1 macrophages enhance expression of Rho-GTPase CDC42 and RhoA. In conclusions, selectively depletion of macrophages suppresses cholestatic liver injuries and fibrosis via the lncRNA-H19 and represents a potential therapeutic strategy for rapid liver fibrosis in BA patients.

Background Biomarker for usefulness in diagnosing advanced fibrosis in nonalcoholic fatty liver disease (NAFLD) is expected. In order to discover novel biomarkers for NAFLD and its pathogenesis, we performed matabolomics screening. Methods (1) The initial cohort was 44 NAFLD patients. (2) This validation cohort was 105 NAFLD patients, 26 primary biliary cirrhosis (PBC) patients, and 48 healthy controls. Using capillary electrophoresis and liquid chromatography with mass spectrometry, we analyzed low molecular weight metabolites in these groups. Results 1. In the initial cohort, we found 28 metabolites associated with advanced fibrosis. Among them, 4 sulfated steroids showed the greatest difference. A decrease of dehydroepiandrosterone sulfate (DHEA-S) and 5α-androstan-3β ol-17-one sulfate (etiocholanolone-S) was observed with the progression of fibrosis. Furthermore, 16 hydroxydehydroepiandrosterone sulfate (16-OH-DHEA-S) increased with the progression of fibrosis. 2. In the validation cohort, the decrease of DHEA-S and etiocholanolone-S, as well as the increase of 16-OH-DHEA-S, with the progression of fibrosis was confirmed. The 16-OH-DHEA-S/DHEA-S ratio and 16-OH-DHEA-S/etiocholanolone-S ratio were even more strongly associated with the grade of fibrosis. Among PBC patients, 16-OH-DHEA-S tended to be higher in stages 3 and 4 than in stages 1 and 2. However, levels of DHEA-S, etiocholanolone-S, and the two ratios were not associated with the stage of PBC. Conclusion Several metabolic products were found to be biomarkers of fibrosis in NAFLD and could also be useful for diagnosis of this condition. Our findings suggested disturbance of hormone metabolism in NAFLD and might lead to the development of new therapy.

Chronic alcohol exposure can lead to liver pathology relating to inflammation and oxidative stress, which are two of the major factors in the incidence of liver fibrosis and even liver cancer. The underlying molecular mechanisms regarding hepatic lesions associated with alcohol are not fully understood. Considering that the recently identified iRhom2 is a key pathogenic mediator of inflammation, we performed in vitro and in vivo experiments to explore its regulatory role in alcohol-induced liver fibrosis. We found that iRhom2 knockout significantly inhibited alcohol-induced inflammatory responses in vitro, including elevated expressions of inflammatory cytokines (IL-1β, IL-6, IL-18, and TNF-α) and genes associated with inflammatory signaling pathways, such as TACE (tumor necrosis factor-alpha converting enzyme), TNFR1 (tumor necrosis factor receptor 1), and TNFR2, as well as the activation of NF-κB. The in vivo results confirmed that long-term alcohol exposure leads to hepatocyte damage and fibrous accumulation. In this pathological process, the expression of iRhom2 is promoted to activate the TACE/NF-κB signaling pathway, leading to inflammatory responses. Furthermore, the deletion of iRhom2 blocks the TACE/NF-κB signaling pathway and reduces liver damage and fibrosis caused by alcohol. Additionally, the activation of the JNK/Nrf2/HO-1 signaling pathway caused by alcohol exposure was also noted in vitro and in vivo. In the same way, knockout or deleting iRhom2 blocked the JNK/Nrf2/HO-1 signaling pathway to regulate the oxidative stress. Therefore, we contend that iRhom2 is a key regulator that promotes inflammatory responses and regulates oxidative stress in alcoholic liver fibrosis lesions. We posit that iRhom2 is potentially a new therapeutic target for alcoholic liver fibrosis.

Background/objective: Malnutrition is a prominent feature in liver cirrhosis, with deleterious impact on clinical outcome. The objective of this study is to investigate whether malnutrition is associated with increased gastrointestinal permeability in liver cirrhosis reflected by altered urinary excretion of non-metabolizable sugar probes. Subjects/methods: Patients with advanced liver cirrhosis (Child Pugh Score B or C) were recruited. Nutritional status was determined according to the Subjective Global Assessment. Intestinal permeability was assessed by measuring the urinary excretion of orally administered, non-metabolized sugar probe molecules. The lactulose/mannitol ratio served as marker for intestinal permeability and reflects non-carrier-mediated transcellular and paracellular transport of the small intestine during the first 5 h. Sucrose recovery in urine within the first 5 h reflects gastroduodenal permeability; sucralose recovery in urine 5–26 h after consumption reflects colonic permeability. Results: Sixty-four patients (56.7±10.8 years; 33% female) were included in the study. Twenty-one patients were considered well nourished according to the Subjective Global Assessment, 23 moderately nourished and 20 patients severely malnourished; 74% had alcoholic liver disease and 67% had cirrhosis stage Child C. Gastroduodenal and colonic permeability was significantly increased in patients with liver cirrhosis compared with 63 healthy controls (0.23±0.22 and 1.37±1.42% vs 0.14±0.10 and 0.41±0.72% in controls), but not different between well and malnourished subjects. Small intestinal permeability (lactulose/mannitol ratio) was increased in all patients (0.069±0.055%) and further increased in malnourished patients (0.048±0.031% vs 0.084±0.061%, P =0.004) due to decreased mannitol recovery only. Conclusions: Gastric, small intestinal and even colonic permeability was altogether increased in liver cirrhosis, and malnutrition was associated with further increased small intestinal permeability indicative of villous atrophy.