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BackgroundMetabolic dysfunction-associated steatohepatitis (MASH) is characterized by persistent inflammatory cascades, with macrophage activation playing a pivotal role. Chitinase 1 (CHIT1), produced by activated macrophages, is a key player in this cascade. In this study, we aimed to explore the role of CHIT1 in MASH with progressive liver fibrosis.MethodsFibrotic liver tissue and serum from distinct patient groups were analyzed using nCounter MAX, flow cytometry, immunohistochemistry, and enzyme-linked immunosorbent assay. A MASH mouse model was constructed to evaluate the effectiveness of OATD-01, a chitinase inhibitor. Macrophage profiling was performed using single-nuclei RNA sequencing and flow cytometry.ResultsCHIT1 expression in fibrotic liver tissues was significantly correlated with the extent of liver fibrosis, macrophages, and inflammation. Single-nuclei RNA sequencing demonstrated a notable increase in macrophages numbers, particularly of lipid-associated macrophages, in MASH mice. Treatment with OATD-01 reduced non-alcoholic fatty liver disease activity score and Sirius red-positive area. Additionally, OATD-01-treated mice had lower CHIT1, F4/80, and α-smooth muscle actin positivity, as well as significantly lower levels of inflammatory markers, pro-fibrotic genes, and matrix remodeling-related mRNAs than vehicle-treated mice. Although the population of F4/80+CD11b+ intrahepatic mononuclear phagocytes remained unchanged, their infiltration and activation (CHIT1+MerTK+) significantly decreased in OATD-01-treated mice, compared with that observed in vehicle-treated mice.ConclusionsOur study underscores the pivotal role of CHIT1 in MASH. The observed significant improvement in inflammation and hepatic fibrosis, particularly at higher doses of the CHIT1 inhibitor, strongly suggests the potential of CHIT1 as a therapeutic target in MASH accompanied by progressive liver fibrosis.

BackgroundIdiosyncratic drug-induced liver injury (DILI) is caused by the interplay among drugs, their metabolites, and the host immune response. The characterization of infiltrated immune cells in the liver may improve the understanding of the pathogenesis of idiosyncratic DILI. This study investigated the phenotypes and clinical implications of liver-infiltrating immune cells in idiosyncratic DILI.MethodsFrom January 2017 to June 2021, 53 patients with idiosyncratic DILI who underwent liver biopsy were prospectively enrolled in this study. Immunohistochemical staining and flow cytometry analyses were performed on the biopsy specimens. Serum levels of CXC chemokine ligand 10 (CXCL10) and soluble CD163 were measured. A multivariate cox proportional hazards model was used to evaluate predictors of DILI resolution within 30 days.ResultsThe numbers of intrahepatic T cells and mononuclear phagocytes were positively correlated with serum levels of total bilirubin, alanine aminotransferase (ALT), and the model of end-stage liver disease score. The frequency of activated CD8+ T cells among liver-infiltrating CD8+ T cells in DILI livers was higher than that in healthy livers. Notably, the percentages of activated intrahepatic CD8+ T cells and mononuclear phagocytes in DILI livers showed a positive correlation with ALT. Additionally, serum CXCL10 level was positively correlated with intrahepatic T cell infiltration and ALT, and soluble CD163 level was positively correlated with intrahepatic mononuclear phagocyte infiltration and ALT. Thirty-six patients (70.6%) were treated with steroids. In multivariate analysis, total bilirubin and steroid use independently influenced DILI resolution within 30 days.ConclusionsActivated CD8+ T cells and mononuclear phagocyte are associated with liver injury caused by drugs. Therefore, we suggest that steroids are a potential treatment option for idiosyncratic DILI.

Background: Metabolic dysfunction-associated steatohepatitis (MASH) is characterized by persistent inflammatory cascades, with macrophage activation playing a pivotal role. Chitinase 1 (CHIT1), produced by activated macrophages, is a key player in this cascade. In this study, we aimed to explore the role of CHIT1 in MASH with progressive liver fibrosis. Methods: Fibrotic liver tissue and serum from distinct patient groups were analyzed using nCounter MAX, flow cytometry, immunohistochemistry, and enzyme-linked immunosorbent assay. A MASH mouse model was constructed to evaluate the effectiveness of OATD-01, a chitinase inhibitor. Macrophage profiling was performed using single-nuclei RNA sequencing and flow cytometry. Results: CHIT1 expression in fibrotic liver tissues was significantly correlated with the extent of liver fibrosis, macrophages, and inflammation. Single-nuclei RNA sequencing demonstrated a notable increase in macrophages numbers, particularly of lipid-associated macrophages, in MASH mice. Treatment with OATD-01 reduced non-alcoholic fatty liver disease activity score and Sirius redpositive area. Additionally, OATD-01-treated mice had lower CHIT1, F4/80, and a-smooth muscle actin positivity, as well as significantly lower levels of inflammatory markers, pro-fibrotic genes, and matrix remodeling-related mRNAs than vehicle-treated mice. Although the population of F4/80+CD11b+ intrahepatic mononuclear phagocytes remained unchanged, their infiltration and activation (CHIT1+MerTK+) significantly decreased in OATD-01-treated mice, compared with that observed in vehicle-treated mice. Conclusions: Our study underscores the pivotal role of CHIT1 in MASH. The observed significant improvement in inflammation and hepatic fibrosis, particularly at higher doses of the CHIT1 inhibitor, strongly suggests the potential of CHIT1 as a therapeutic target in MASH accompanied by progressive liver fibrosis. [ABSTRACT FROM AUTHOR]

Recipients of liver transplantation (LT) require long-term immunosuppressive drug treatment, but lifelong immunosuppressive treatment has severe side effects. It is known that some LT recipients develop immune tolerance, and although the development of such operational tolerance should allow a decrease in the burden of immunosuppressive drug treatment, the factors that indicate operational tolerance are not clear. This study aimed to monitor immunological markers over time in LT recipients to identify those markers indicating the development of operational tolerance. We performed a prospective pilot study measuring immune markers, including the ratio of regulatory T (Treg) and T helper (Th) 17 cells in peripheral blood in the 14 most immunologically stable patients among 70 clinically stable LT recipients. The doses of immunosuppressive drugs given to these 14 LT recipients were tapered over time and they were monitored for immunological markers related to the development of immune tolerance. As the doses of immunosuppressive drugs were reduced, the Treg/Th17, Th1/Th17, and CD8/Th17 ratio in tolerant recipients was significantly increased compared with that of nontolerant recipients. These results suggest that monitoring of changes in the immune makers, including Treg/Th17 ratio during tapering of immunosuppression may allow prediction of the development of tolerance.

Background: Idiosyncratic drug-induced liver injury (DILI) is caused by the interplay among drugs, their metabolites, and the host immune response. The characterization of infiltrated immune cells in the liver may improve the understanding of the pathogenesis of idiosyncratic DILI. This study investigated the phenotypes and clinical implications of liver-infiltrating immune cells in idiosyncratic DILI. Methods: From January 2017 to June 2021, 53 patients with idiosyncratic DILI who underwent liver biopsy were prospectively enrolled in this study. Immunohistochemical staining and flow cytometry analyses were performed on the biopsy specimens. Serum levels of CXC chemokine ligand 10 (CXCL10) and soluble CD163 were measured. A multivariate cox proportional hazards model was used to evaluate predictors of DILI resolution within 30 days. Results: The numbers of intrahepatic T cells and mononuclear phagocytes were positively correlated with serum levels of total bilirubin, alanine aminotransferase (ALT), and the model of end-stage liver disease score. The frequency of activated CD8+ T cells among liver-infiltrating CD8+ T cells in DILI livers was higher than that in healthy livers. Notably, the percentages of activated intrahepatic CD8+ T cells and mononuclear phagocytes in DILI livers showed a positive correlation with ALT. Additionally, serum CXCL10 level was positively correlated with intrahepatic T cell infiltration and ALT, and soluble CD163 level was positively correlated with intrahepatic mononuclear phagocyte infiltration and ALT. Thirty-six patients (70.6%) were treated with steroids. In multivariate analysis, total bilirubin and steroid use independently influenced DILI resolution within 30 days. Conclusions: Activated CD8+ T cells and mononuclear phagocyte are associated with liver injury caused by drugs. Therefore, we suggest that steroids are a potential treatment option for idiosyncratic DILI. [ABSTRACT FROM AUTHOR]

BackgroundProgrammed death-ligand 1 (PD-L1) expression is abundant not only in malignant cells but also in infiltrating cells within the tumor microenvironment (TME) of hepatocellular carcinoma (HCC). This study explored the association between PD-L1 expression in TME and outcomes in HCC patients treated with atezolizumab plus bevacizumab (AB), emphasizing the implications of PD-L1 expression in both malignant and tumor-infiltrating cells.MethodsThis study included 72 patients with HCC who underwent percutaneous core needle liver biopsy before AB treatment between September 2020 and December 2023. PD-L1 expression on tumor tissues was assessed using the combined positive score (CPS) with cutoff values of 1 and 10, utilizing antibody clone 22C3 (Dako).ResultsThe distribution of PD-L1 CPS included 24 patients with CPS

Although rejection or tolerance can occur in liver transplantation (LT) patients, there are no reliable non-invasive methods for predicting immune homeostasis. In this study, we developed a humanized mouse model to predict liver immune homeostasis in patients who underwent LT. The patient-derived avatar model was developed by injecting peripheral blood mononuclear cells from healthy controls (HCs) or LT patients with stable, rejection, or tolerance into NOD.Cg-PrkdcscidIL2rgtm1Wjl/SzJ (NSG) mice, followed by injection of human hepatic stellate cells and Carbone tetrachloride (CCl4). After 7 weeks, the patient’s T-cell engraftment and liver inflammation in the avatar model were evaluated and compared with the liver histology of LT patients. Changes in liver inflammation following treatment with tacrolimus and/or biguanide derivatives were also examined. The C-X-C Motif Chemokine Receptor 3 (CXCR3)-dependently engrafted patient T cells led to differences in liver inflammation in our model according to the status of LT patients. The livers of avatar models from rejection patients had severe inflammation with more T helper 17 cells and fewer regulatory T cells compared to those of models from tolerance and HCs showing only mild inflammation. Moreover, our model classified stable post-LT patients into severe and mild inflammation groups, which correlated well with liver immunity in these patients. Our models revealed alleviation of inflammation after combination treatment with tacrolimus and biguanide derivatives or monotherapy. Consequently, using our new patient-derived avatar model, we predicted liver immune homeostasis in patients with stable LT without biopsy. Moreover, our avatar model may be useful for preclinical analysis to evaluate treatment responses while reducing risks to patients.

We examined the effect of combination therapy with metformin and tacrolimus on immune parameters including T regulatory (Treg) and type 17 helper T (Th17) cells in vitro and in vivo in mice and in liver transplantation (LT) patients. T cell proliferation and subtypes after in vitro T cell activation or allogeneic stimulation were evaluated. RNA sequencing and microarray analysis were used to evaluate differences in gene expression. Metformin and tacrolimus were administered to mice with graft-versus-host disease (GVHD) and the effects in vivo were assessed. Five LT patients were treated with metformin and the changes in Treg and Th17 cells examined. Combination therapy decreased Type 1 helper T (Th1) and Th17 cells present after in vitro T cell activation, whereas genes associated with Treg were overexpressed. During in vitro allogeneic stimulation, combination therapy increased Treg cells and decreased T cell proliferation and pro-inflammatory markers. In mice with GVHD, combination treatment decreased the clinical and pathological severity of GVHD. In LT patients, addition of metformin increased the peripheral percentage of CD4+Treg and CD8+Treg cells and decreased CD4+Th17. Our study suggests that the addition of metformin to tacrolimus may improve immunological balance by increasing Treg cells and decreasing Th17 cells.