Primary biliary cholangitis: Old and novel therapy

Bile acid therapy for primary biliary cholangitis: Pathogenetic validation

Knowledge of the etiological and pathogenetic mechanisms of the development of any disease is essential for its treatment. Because the cause of primary biliary cholangitis (PBC), a chronic, slowly progressive cholestatic liver disease, is still unknown, treatment remains symptomatic. Knowledge of the physicochemical properties of various bile acids and the adaptive responses of cholangiocytes and hepatocytes to them has provided an important basis for the development of relatively effective drugs based on hydrophilic bile acids that can potentially slow the progression of the disease. Advances in the use of hydrophilic bile acids for the treatment of PBC are also associated with the discovery of pathogenetic mechanisms of the development of cholangiocyte damage and the appearance of the first signs of this disease. For 35 years, ursodeoxycholic acid (UDCA) has been the unique drug of choice for the treatment of patients with PBC. In recent years, the list of hydrophilic bile acids used to treat cholestatic liver diseases, including PBC, has expanded. In addition to UDCA, the use of obeticholic acid, tauroursodeoxycholic acid and norursodeoxycholic acid as drugs is discussed. The pathogenetic rationale for treatment of PBC with various bile acid drugs is discussed in this review. Emphasis is made on the mechanisms explaining the beneficial therapeutic effects and potential of each of the bile acid as a drug, based on the understanding of the pathogenesis of the initial stages of PBC.

Uncovering the pharmacological mechanism and the main herbal medicine contributing to the efficacy of Xiaoyanlidan Tablet (XYLDT) in treating cholestatic liver injury

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaoyanlidan Tablet (XYLDT) is a Chinese patent medicine consisted of three traditional Chinese medicines (TCMs) including Andrographis Herba (AH), Linearstripe Rabdosia Herba (LRH) and Picrasmae Ramulus et Folium (PRF). In Chinese traditional medicine theory, XYLDT has the "heat-clearing, dampness-dispelling and gallbladder function promoting" properties, and was widely used in the clinic for decades to treat pain in the subcostal region or bitter taste in the mouth, which were induced by liver-gallbladder dampness-heat. Meanwhile, it was also used for the therapy of acute cholecystitis and cholangitis.

AIM OF THE STUDY

To explore the mechanism of XYLDT in alleviating the alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury (CLI), and to find out which TCM consisted in XYLDT contributed the most to the therapeutic efficacy of XYLDT.

METHODS

ANIT was orally given to mice to induce CLI in vivo. Each TCM in XYLDT alone, XYLDT-without one TCM or XYLDT was orally given to mice before or after ANIT administration. Serum biochemical indicators were measured by using commercial kits. Liver histopathology was observed. Clinical data analysis was used to predict molecules and signal pathways involved in the XYLDT-provided improvement on CLI, which was further verified by using RT-PCR and Western-blot assay.

RESULTS

The alleviation of XYLDT on ANIT-induced CLI was proved by the data of serum biochemical indicators and liver histological observation. Results from clinical data analysis indicated that XYLDT improved CLI via improving mitochondrial function, oxidative phosphorylation, oxidative stress. XYLDT reduced the ROS level, MDA content, and increased GSH content. Meanwhile XYLDT improved the level of Nrf2 into the nucleus and mRNA expression of Nqo1, Gclc, Gclm. Andrographis Herba was proved to be the most crucial for the XYLDT-provided therapeutic efficacy on CLI. Moreover, andrographolide and neoandrographolide, two main active compounds in Andrographis Herba, had the apparent anti-inflammatory ability in LPS-stimulated RAW264.7 cells. Andrographolide also promoted nuclear translocation activation of Nrf2 in antioxidant response elements (ARE)-luciferin transfected L-02 cells.

CONCLUSION

XYLDT alleviated the ANIT-induced CLI via improving oxidative stress and activated Nrf2-related signaling pathways. Andrographis Herba was important for the XYLDT-provided alleviation on CLI.

An efficient measure for the isolation of chenodeoxycholic acid from chicken biles using enzyme-assisted extraction and macroporous resins refining

Chicken bile is a by-product of chicken processing, rich in chenodeoxycholic acid (CDCA), an active pharmaceutical raw material. In this study, a green measure for the extraction and purification of CDCA from chicken biles by enzymatic hydrolysis and macroporous resins refining was established. For the assisted extraction of CDCA, the active bile salt hydrolase (BSH) from Bifidobacterium was heterologously expressed and applied, its activities on GCDCA and TCDCA were 4.96 ± 0.32 U/mg and 3.07 ± 0.031 U/mg and optimal catalytic conditions for the extraction of CDCA were determined as 0.04 g/g of the enzyme dosage, pH 5.0 and 38 °C. Through validation of the conditions, the yield of CDCA was up to 5.32 %, which was equivalent to that by saponification method. In order to further refine CDCA from the extract obtained by enzyme-assisted extraction, a more preferable resin, AB-8 was selected for the purification of CDCA, which had a good adsorption capacity of 61.06 ± 0.57 mg/g for CDCA. Besides, the obtained CDCA extract was purified through AB-8 resin, the purity of CDCA was improved from 51.7 % to 91.4 % and the recovery yield of CDCA was 87.8 %. The advantages of energy conservation, time saving, economy and environmental friendliness make the measure using enzyme-assisted extraction and macroporous resins refining a promising candidate for isolation of CDCA from chicken bile.

Metabolomics and serum pharmacochemistry combined with network pharmacology uncover the potential effective ingredients and mechanisms of Yin-Chen-Si-Ni Decoction treating ANIT-induced cholestatic liver injury

ETHNOPHARMACOLOGICAL RELEVANCE

Yin-Chen-Si-Ni Decoction is a classical traditional Chinese medicine (TCM) prescription that is used clinically for treating cholestatic liver injury (CLI) and other hepatic diseases. However, the material basis and underlying mechanisms of YCSND are not clear.

AIM OF THE STUDY

To investigate effective components and mechanisms of YCSND in the treatment of CLI using serum pharmacochemistry, metabolomics, and network pharmacology.

MATERIALS AND METHODS

Biochemical indicators, liver index, and histopathology analysis were adopted to evaluate the protective effect of YCSND on ANIT-induced CLI rats. Then, a UPLC-Q-Exactive Orbitrap MS/MS analysis of the migrant components in serum and liver including prototype and metabolic components was performed in YCSND. In addition, a study of the endogenous metabolites using serum and liver metabolomics was performed to discover potential biomarkers, metabolic pathways, and associated mechanisms. Further, the network pharmacology oriented by in vivo migrant components was also used to pinpoint the active ingredients, core targets, and signaling pathways of YCSND. Finally, molecular docking and molecular dynamics simulation (MDS) were used to predict the binding ability between components and core targets, and a real-time qPCR (RT-qPCR) experiment was used to measure the mRNA expression of the core target genes.

RESULTS

Pharmacodynamic studies suggest that YCSND could exert obvious hepatoprotective effects on CLI rats. Furthermore, 68 compounds, comprising 32 prototype components and 36 metabolic components from YCSND, were found by serum pharmacochemistry analysis. Network pharmacology combining molecular docking and MDS showed that apigenin, naringenin, 18β-glycyrrhetinic acid, and isoformononetin have better binding ability to 6 core targets (EGFR, AKT1, IL6, MMP9, CASP3, PPARG). Additionally, PI3K, TNF-α, MAPK3, and six core target genes in liver tissues were validated with RT-qPCR. Metabolomics revealed the anti-CLI effects of YCSND by regulating four metabolic pathways of primary bile acid and biosynthesis, phenylalanine, tyrosine and tryptophan biosynthesis, taurine and hypotaurine metabolism, and arachidonic acid metabolism. Integrating metabolomics and network pharmacology identified four pathways related to CLI, including the PI3K-Akt, HIF-1, MAPK, and TNF signaling pathway, which revealed multiple mechanisms of YCSND against CLI that might involve anti-inflammatory and apoptosis.

CONCLUSION

The research based on serum pharmacochemistry, network pharmacology, and metabolomics demonstrates the beneficial hepatoprotective effects of YCSND on CLI rats by regulating multiple components, multiple targets, and multiple pathways, and provides a potent means of illuminating the material basis and mechanisms of TCM prescriptions.

Pirfenidone ameliorates ANIT-induced cholestatic liver injury via modulation of FXR, NF-кB/TNF-α, and Wnt/GSK-3β/β-catenin signaling pathways

Cholestasis is a hepatobiliary disorder characterized by the excessive accumulation of toxic bile acids in hepatocytes, leading to cholestatic liver injury (CLI) through multiple pathogenic inflammatory pathways. Currently, there are limited therapeutic options for the management of cholestasis and associated CLI; therefore, new options are urgently needed. Pirfenidone (PF), an oral bioavailable pyridone analog, is used for the treatment of idiopathic pulmonary fibrosis. PF has recently demonstrated diverse potential therapeutic activities against different pathologies. Accordingly, the present study adopted the α-naphthyl isothiocyanate (ANIT)-induced CLI model in mice to explore the potential protective impact of PF and investigate the underlying mechanisms of action. PF intervention markedly reduced the serum levels of ALT, AST, LDH, total bilirubin, and total bile acids, which was accompanied by a remarkable amelioration of histopathological lesions induced by ANIT. PF also protected the mice against ANIT-induced redox imbalance in the liver, represented by reduced MDA levels and elevated GSH and SOD activities. Mechanistically, PF inhibited ANIT-induced downregulated expressions of the farnesoid X receptor (FXR), as well as the bile salt export pump (BSEP) and the multidrug resistance-associated protein 2 (MRP2) bile acid efflux channels. PF further repressed ANIT-induced NF-κB activation and TNF-α and IL-6 production. These beneficial effects were associated with its ability to dose-dependently inhibit Wnt/GSK-3β/β-catenin/cyclin D1 signaling. Collectively, PF protects against ANIT-induced CLI in mice, demonstrating powerful antioxidant and anti-inflammatory activities as well as an ability to oppose BA homeostasis disorder. These protective effects are primarily mediated by modulating the interplay between FXR, NF-κB/TNF-α/IL-6, and Wnt/β-catenin signaling pathways.

Emodin alleviates cholestatic liver injury by modulating Sirt1/Fxr signaling pathways

Emodin (EMO) has the effect of anti-cholestasis induced by alpha-naphthylisothiocyanate (ANIT). But its mechanism is still unclear. The farnesoid X receptor (Fxr) is the master bile acid nuclear receptor. Recent studies have reported that Sirtuin 1 (Sirt1) can regulate the activities of Fxr. The purpose of the current study was to investigate the mechanism of EMO against ANIT-induced liver injury based on Sirt1/Fxr signaling pathway. The ANIT-induced cholestatic rats were used with or without EMO treatment. Serum biochemical indicators, as well as liver histopathological changes were examined. The genes expressions of Sirt1, Fxr, Shp, Bsep and Mrp2 were detected. The expressions of Sirt1, Fxr and their downstream related genes were investigated in vitro. The results showed that EMO significantly alleviated ANIT-induced liver injury in rats, and increased Sirt1, Fxr, Shp, Bsep and Mrp2 gene expression in liver, while decreased the expression of Cyp7a1. EMO significantly activated Fxr, while Sirt1 inhibitor and Sirt1 gene silencing significantly reduced Fxr activity in vitro. Collectively, EMO in the right dose has a protective effect on liver injury induced by ANIT, and the mechanism may be through activation of Fxr by Sirt1, thus regulating bile acid metabolism, and reducing bile acid load in hepatocytes.

Risk prediction of cholangitis after stent implantation based on machine learning

The risk of cholangitis after ERCP implantation in malignant obstructive jaundice patients remains unknown. To develop models based on artificial intelligence methods to predict cholangitis risk more accurately, according to patients after stent implantation in patients' MOJ clinical data. This retrospective study included 218 patients with MOJ undergoing ERCP surgery. A total of 27 clinical variables were collected as input variables. Seven models (including univariate analysis and six machine learning models) were trained and tested for classified prediction. The model' performance was measured by AUROC. The RFT model demonstrated excellent performances with accuracies up to 0.86 and AUROC up to 0.87. Feature selection in RF and SHAP was similar, and the choice of the best variable subset produced a high performance with an AUROC up to 0.89. We have developed a hybrid machine learning model with better predictive performance than traditional LR prediction models, as well as other machine learning models for cholangitis based on simple clinical data. The model can assist doctors in clinical diagnosis, adopt reasonable treatment plans, and improve the survival rate of patients.

Exploring the effect and mechanism of cucurbitacin B on cholestatic liver injury based on network pharmacology and experimental verification

ETHNOPHARMACOLOGICAL RELEVANCE

Cholestatic liver injury (CLI) is a pathologic process with the impairment of liver and bile secretion and excretion, resulting in an excessive accumulation of bile acids within the liver, which leads to damage to both bile ducts and hepatocytes. This process is often accompanied by inflammation. Cucumis melo L is a folk traditional herb for the treatment of cholestasis. Cucurbitacin B (CuB), an important active ingredient in Cucumis melo L, has significant anti-inflamamatory effects and plays an important role in diseases such as neuroinflammation, skin inflammation, and chronic hepatitis. Though numerous studies have confirmed the significant therapeutic effect of CuB on liver diseases, the impact of CuB on CLI remains uncertain. Consequently, the objective of this investigation is to elucidate the therapeutic properties and potential molecular mechanisms underlying the effects of CuB on CLI.

AIM OF THE STUDY

The aim of this paper was to investigate the potential protective mechanism of CuB against CLI.

METHODS

First, the corresponding targets of CuB were obtained through the SwissTargetPrediction and SuperPre online platforms. Second, the DisGeNET database, GeneCards database, and OMIM database were utilized to screen therapeutic targets for CLI. Then, protein-protein interaction (PPI) was determined using the STRING 11.5 data platform. Next, the OmicShare platform was employed for the purpose of visualizing the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The molecular docking technique was then utilized to evaluate the binding affinity existing between potential targets and CuB. Subsequently, the impacts of CuB on the LO2 cell injury model induced by Lithocholic acid (LCA) and the CLI model induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) were determined by evaluating inflammation in both in vivo and in vitro settings. The potential molecular mechanism was explored by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot (WB) techniques.

RESULTS

A total of 122 CuB targets were collected and high affinity targets were identified through the PPI network, namely TLR4, STAT3, HIF1A, and NFKB1. GO and KEGG analyses indicated that the treatment of CLI with CuB chiefly involved the inflammatory pathway. In vitro study results showed that CuB alleviated LCA-induced LO2 cell damage. Meanwhile, CuB reduced elevated AST and ALT levels and the release of inflammatory factors in LO2 cells induced by LCA. In vivo study results showed that CuB could alleviate DDC-induced pathological changes in mouse liver, inhibit the activity of serum transaminase, and suppress the liver and systemic inflammatory reaction of mice. Mechanically, CuB downregulated the IL-6, STAT3, and HIF-1α expression and inhibited STAT3 phosphorylation.

CONCLUSION

By combining network pharmacology with in vivo and in vitro experiments, the results of this study suggested that CuB prevented the inflammatory response by inhibiting the IL-6/STAT3/HIF-1α signaling pathway, thereby demonstrating potential protective and therapeutic effects on CLI. These results establish a scientific foundation for the exploration and utilization of natural medicines for CLI.

Optimal drug regimens for improving ALP biochemical levels in patients with primary biliary cholangitis refractory to UDCA: a systematic review and Bayesian network meta-analysis

BACKGROUND

Up to 40% of UDCA-treated patients do not have an adequate clinical response. Farnesoid X receptor agonists, peroxisome proliferator-activated receptor agonists, and fibroblast growth factor 19 analogs were developed as adjunctive therapy. The aim of this network meta-analysis was to compare the efficacy of these drugs as add-on therapy for patients with primary biliary cholangitis (PBC) refractory to UDCA in improving ALP levels.

METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane Library for eligible studies until 1 December 2023. Randomized controlled trials, cohort studies, and case-control studies comparing the efficacy of different combination treatments and UDCA monotherapy in UDCA-refractory PBC patients were included in the analysis. Cumulative probability was used to rank the included treatments.

RESULTS

A total of 23 articles were eligible for our network meta-analysis. In terms of improving ALP levels, In terms of improving ALP biochemical levels, bezafibrate combined with UDCA (MD 104.49, 95% CI 60.41, 161.92), fenofibrate combined with UDCA (MD 87.81, 95% CI (52.34, 129.79), OCA combined with UDCA (MD 65.21, 95% CI 8.99, 121.80), seladelpar combined with UDCA (MD 117.39, 95% CI 19.97, 213.95), elafibranor combined with UDCA (MD 140.73, 95% CI 74.34, 209.98), saroglitazar combined with UDCA (MD 132.09, 95% CI 13.99, 247.04) was more effective than UDCA monotherapy. Elafibranor in combination with UDCA was the most likely (32%) to be the optimal drug regimen.

CONCLUSION

As second-line therapy for UDCA-refractory PBC, PPAR agonists were more effective than any other drugs with other mechanisms in improving ALP biochemical levels, with elafibranor being the best.

Mitigation of intrahepatic cholestasis induced by 17α-ethinylestradiol via nanoformulation of Silybum marianum L

BACKGROUND

Cholestasis is an important predisposing factor for hepatocyte damage, liver fibrosis, primary biliary cirrhosis, and even liver failure. Silybum marianum L. (SM) plant is used in teas or eaten in some countries due to its antioxidant and hepatoprotective properties. Because of its low and poor oral bioavailability, so we improve the therapeutic activity of Silybum marianum L. extract (SM) by studying the potential effects of nanoformulation of Silybum marianium L. extract (nano-SM) on 17α-ethinylestradiol (EE)-induced intrahepatic cholestasis.

METHODS

Thirty female Sprague-Dawley rats were divided into 5 groups (6 rats/group). Group I: Rats were received the treatment vehicle and served as normal group. Group II:Rats were injected daily with EE (10 mg/kg) for five successive days. Group III-V: Rats were injected daily with EE (10 mg/kg) and treated with either Ursodeoxycholic acid (UDCA) (40 mg/kg), SM (100 mg/kg) and nano-SM (100 mg/kg) orally once/day throughout the trialfor five successive days, respectively.

RESULTS

Nano-SM greatly dampened the increase in serum levels of total and direct bilirubin, alanine aminotransaminase, aspartate aminotransaminase, and alkaline phosphatase caused by EE. Furthermore, nano-SM increased the hepatic contents of reduced glutathione (GSH) and catalase (CAT) and also upregulated the relative hepatic gene expressions of Rho-kinase (ROCK-1), myosin light chain kinase (MLCK), and myosin phosphatase target subunit (MYPT1) compared to the EE-induced group. Administration of nano-SM reduced hepatic lipid peroxidation and downregulated the relative hepatic expressions of the nuclear factor-kappa B (NF-ҡB) and interleukin-1β (IL-1β). In addition, nano-SM improved the histopathological changes induced by EE.

CONCLUSION

Nano-SM possessed a superior effect over SM, which can be considered an effective protective modality against EE-induced cholestatic liver injury through its antioxidant, anti-inflammatory activities, and enhancing bile acid (BA) efflux.

Ursodeoxycholic Acid's Effectiveness in the Management of Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis

Aim

This meta-analysis's objective was to assess the effectiveness of ursodeoxycholic acid (UDCA) in the management of nonalcoholic fatty liver disease (NAFLD).

Methods

Electronic databases like PubMed, Embase, Scopus, and Cochrane Library were thoroughly looked for randomized controlled trials determining ursodeoxycholic acid's (UDCAs) effectiveness on the serum liver function tests in NAFLD patients. After screening, seven randomized controlled trials were incorporated overall. Utilizing a fixed effects model, quantitative data synthesis was performed in R version 4.3.1.

Results

The meta-analysis showed significant reductions in alanine transaminase (ALT) (p ≤ 0.0001), aspartate transaminase (p = 0.0009), and gamma-glutamyl transferase (GGT) (p ≤ 0.0001) after UDCA therapy. However, significant reductions in bilirubin (p = 0.6989) and alkaline phosphatase (ALP) (p = 0.1172) levels were not noted. Sensitivity analysis by removing the studies with some concerns of bias was successful in demonstrating a remarkable reduction in heterogeneity for aspartate transaminase and ALP, which was also observed while performing the subgroup analyses via dosage.

Conclusion

Ursodeoxycholic acid was beneficial in patients diagnosed with NAFLD as it significantly reduced aspartate transaminase, ALT and GGT levels. However, more randomized controlled trials are required to be conducted in the future to increase the certainty of the evident findings.

Clinical significance

This meta-analysis strengthens the evidence about the reductions in AST, ALT, and GGT levels observed with ursodeoxycholic acid therapy in NAFLD patients by pooling the data together from the latest RCTs thus proving its hepatoprotective effects which can be beneficial in preventing the associated complications.

How to cite this article

Patel VS, Mahmood SF, Bhatt KH, et al. Ursodeoxycholic Acid's Effectiveness in the Management of Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-analysis. Euroasian J Hepato-Gastroenterol 2024;14(1):92-98.

Exploring the Potential Mechanisms of Action of Gentiana Veitchiorum Hemsl. Extract in the Treatment of Cholestasis using UPLC-MS/MS, Systematic Network Pharmacology, and Molecular Docking

INTRODUCTION

Gentiana veitchiorum Hemsl. (GV) has a long history in Tibetan medicine for treating hepatobiliary disease cholestasis. However, the mechanisms mediating its efficacy in treating cholestasis have yet to be determined.

AIM

To elucidate the mechanisms of action of GV in the treatment of cholestasis, an integrated approach combining ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis with network pharmacology was established.

MATERIALS AND METHODS

A comprehensive analysis of the chemical composition of GV was achieved by UPLC-MS/MS. Subsequently, a network pharmacology method that integrated target prediction, a protein-protein interaction (PPI) network, gene set enrichment analysis, and a component- target-pathway network was established, and finally, molecular docking and experiments in vitro were conducted to verify the predicted results.

RESULTS

Twenty compounds that were extracted from GV were identified by UPLC-MS/MS analysis. Core proteins such as AKT1, TNF, and IL6 were obtained through screening in the Network pharmacology PPI network. The Kyoto Encyclopedia of the Genome (KEGG) pathway predicted that GV could treat cholestasis by acting on signaling pathways such as TNF/IL-17 / PI3K-Akt. Network pharmacology suggested that GV might exert a therapeutic effect on cholestasis by regulating the expression levels of inflammatory mediators, and the results were further confirmed by the subsequent construction of an LPS-induced RAW 264.7 cell model.

CONCLUSIONS

In this study, UPLC-MS/MS analysis, network pharmacology, and experiment validation were used to explore potential mechanisms of action of GV in the treatment of cholestasis.

Gut microbiota-mediated C-sulfonate metabolism impairs the bioavailability and anti-cholestatic efficacy of andrographolide

Cholestatic liver injury results from the accumulation of toxic bile acids in the liver, presenting a therapeutic challenge with no effective treatment available to date. Andrographolide (AP) has exhibited potential as a treatment for cholestatic liver disease. However, its limited oral bioavailability poses a significant obstacle to harnessing its potent therapeutic properties and restricts its clinical utility. This limitation is potentially attributed to the involvement of gut microbiota in AP metabolism. In our study, employing pseudo-germ-free, germ-free and strain colonization animal models, along with 16S rRNA and shotgun metagenomic sequencing analysis, we elucidate the pivotal role played by gut microbiota in the C-sulfonate metabolism of AP, a process profoundly affecting its bioavailability and anti-cholestatic efficacy. Subsequent investigations pinpoint a specific enzyme, adenosine-5'-phosphosulfate (APS) reductase, predominantly produced by Desulfovibrio piger, which catalyzes the reduction of SO42- to HSO3-. HSO3- subsequently interacts with AP, targeting its C=C unsaturated double bond, resulting in the formation of the C-sulfonate metabolite, 14-deoxy-12(R)-sulfo andrographolide (APM). Inhibition of APS reductase leads to a notable enhancement in AP bioavailability and anti-cholestatic efficacy. Furthermore, employing RNA sequencing analysis and farnesoid X receptor (FXR) knockout mice, our findings suggest that AP may exert its anti-cholestatic effects by activating the FXR pathway to promote bile acid efflux. In summary, our study unveils the significant involvement of gut microbiota in the C-sulfonate metabolism of AP and highlights the potential benefits of inhibiting APS reductase to enhance its therapeutic effects. These discoveries provide valuable insights into enhancing the clinical applicability of AP as a promising treatment for cholestatic liver injury.

Unfolded Protein Response Signaling in Liver Disorders: A 2023 Updated Review

Endoplasmic reticulum (ER) is the site for synthesis and folding of secreted and transmembrane proteins. Disturbance in the functioning of ER leads to the accumulation of unfolded and misfolded proteins, which finally activate the unfolded protein response (UPR) signaling. The three branches of UPR-IRE1 (Inositol requiring enzyme 1), PERK (Protein kinase RNA-activated (PKR)-like ER kinase), and ATF6 (Activating transcription factor 6)-modulate the gene expression pattern through increased expression of chaperones and restore ER homeostasis by enhancing ER protein folding capacity. The liver is a central organ which performs a variety of functions which help in maintaining the overall well-being of our body. The liver plays many roles in cellular physiology, blood homeostasis, and detoxification, and is the main site at which protein synthesis occurs. Disturbance in ER homeostasis is triggered by calcium level imbalance, change in redox status, viral infection, and so on. ER dysfunction and subsequent UPR signaling participate in various hepatic disorders like metabolic (dysfunction) associated fatty liver disease, liver cancer, viral hepatitis, and cholestasis. The exact role of ER stress and UPR signaling in various liver diseases is not fully understood and needs further investigation. Targeting UPR signaling with drugs is the subject of intensive research for therapeutic use in liver diseases. The present review summarizes the role of UPR signaling in liver disorders and describes why UPR regulators are promising therapeutic targets.

Bile Acid Sequestration via Colesevelam Reduces Bile Acid Hydrophobicity and Improves Liver Pathology in Cyp2c70-/- Mice with a Human-like Bile Acid Composition

Bile acids (BAs) and their signaling pathways have been identified as therapeutic targets for liver and metabolic diseases. We generated Cyp2c70-/- (KO) mice that were not able to convert chenodeoxycholic acid into rodent-specific muricholic acids (MCAs) and, hence, possessed a more hydrophobic, human-like BA pool. Recently, we have shown that KO mice display cholangiopathic features with the development of liver fibrosis. The aim of this study was to determine whether BA sequestration modulates liver pathology in Western type-diet (WTD)-fed KO mice. The BA sequestrant colesevelam was mixed into the WTD (2% w/w) of male Cyp2c70+/+ (WT) and KO mice and the effects were evaluated after 3 weeks of treatment. Colesevelam increased fecal BA excretion in WT and KO mice and reduced the hydrophobicity of biliary BAs in KO mice. Colesevelam ameliorated diet-induced hepatic steatosis in WT mice, whereas KO mice were resistant to diet-induced steatosis and BA sequestration had no additional effects on liver fat content. Total cholesterol concentrations in livers of colesevelam-treated WT and KO mice were significantly lower than those of untreated controls. Of particular note, colesevelam treatment normalized plasma levels of liver damage markers in KO mice and markedly decreased hepatic mRNA levels of fibrogenesis-related genes in KO mice. Lastly, colesevelam did not affect glucose excursions and insulin sensitivity in WT or KO mice. Our data show that BA sequestration ameliorates liver pathology in Cyp2c70-/- mice with a human-like bile acid composition without affecting insulin sensitivity.

Emerging Therapeutic Strategies in The Fight Against Primary Biliary Cholangitis

The liver has a vital role in many metabolic and regulatory processes in the body. Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is a chronic cholestatic autoimmune disease of the intrahepatic bile ducts associated with loss of tolerance to mitochondrial antigens. At this time there is no definitive cure for PBC; however, ursodeoxycholic acid (UDCA) has been shown to reduce injury when administered as the first line of treatment. Additional therapeutics can be given concurrently or as an alternative to UDCA to manage the symptoms and further curb disease progression. Currently, a liver transplant is the only potentially curative option when the patient has developed end-stage liver disease or intractable pruritus. This review aims to delineate the pathogenesis of primary biliary cholangitis and shed light on current therapeutic strategies in the treatment of PBC.

The choleretic role of tauroursodeoxycholic acid exacerbates alpha-naphthylisothiocyanate induced cholestatic liver injury through the FXR/BSEP pathway

The aim of this study was to determine the effect of tauroursodeoxycholic acid (TUDCA) on the alpha-naphthylisothiocyanate (ANIT)-induced model of cholestasis in mice. Wild-type and farnesoid X receptor (FXR)-deficient (Fxr^-/- ) mice were used to generate cholestasis models by gavage with ANIT. Obeticholic acid (OCA) was used as a positive control. In wild-type mice, treatment with TUDCA for 7 days resulted in a dramatic increase in serum levels of alanine aminotransferase (ALT), with aggravation of bile infarcts and hepatocyte necrosis with ANIT-induction. TUDCA activated FXR to upregulate the expression of bile salt export pump (BSEP), increasing bile acids (BAs)-dependent bile flow, but aggravating cholestatic liver injury when bile ducts were obstructed resulting from ANIT. In contrast, TUDCA improved the liver pathology and decreased serum ALT and alkaline phosphatase (ALP) levels in ANIT-induced Fxr^-/- mice. Furthermore, TUDCA inhibited the expression of cleaved caspase-3 and reduced the area of terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining in the model mice. TUDCA also upregulated anion exchanger 2 (AE2) protein expression, protecting cholangiocytes against excessive toxic BAs. Our results showed that TUDCA aggravated cholestatic liver injury via the FXR/BSEP pathway when bile ducts were obstructed, although TUDCA inhibited apoptotic activity and protected cholangiocytes against excessive toxic BAs.

iNKT17 cells play a pathogenic role in ethinylestradiol-induced cholestatic hepatotoxicity

IL-17 is closely associated with inflammation in intrahepatic cholestasis (IHC). Targeting IL-17 ameliorates IHC in mice. Invariant natural killer T (iNKT) cells are predominantly enriched in the liver and they mediate drug-induced liver injury through their secreted cytokines. However, whether iNKT17 cells are involved in ethinylestradiol (EE)-induced IHC remains unclear. In the present study, the administration of EE (10 mg/kg in vivo and 6.25 μM in vitro) promoted the activation and expansion of iNKT17 cells, which contributed to a novel hepatic iNKT17/Treg imbalance. iNKT cell-deficient Jα18-/- mice and the RORγt inhibitor digoxin (20 μg) alleviated EE-induced cholestatic hepatotoxicity and downregulated the IL-17 signalling pathway. In contrast, the co-administration of EE with recombinant IL-17 (1 μg) to Jα18-/- mice induced cholestatic hepatotoxicity and increased the infiltration of hepatic neutrophils and monocytes. Importantly, the administration of IL-17-/- iNKT cells (3.5 × 105) to Jα18-/- mice resulted in the attenuation of hepatotoxicity and the recruitment of fewer hepatic neutrophils and monocytes than the adoptive transfer of wild-type iNKT cells. These results indicated that iNKT17 cells could exert pathogenic effects. The recruitment and activation of iNKT17 cells could be attributed to the high level of CXCR3 expression on their surface. CXCL10 deficiency ameliorated EE-induced cholestatic liver damage, reduced hepatic CXCR3+ iNKT cells and inhibited RORγt expression. These findings suggest that iNKT17 cells play a key role in EE-induced cholestatic liver injury via CXCR3-mediated recruitment and activation. Our study provides new insights and therapeutic targets for cholestatic diseases.

Fluorofenidone ameliorates cholestasis and fibrosis by inhibiting hepatic Erk/-Egr-1 signaling and Tgfβ1/Smad pathway in mice

Cholestasis is characterized by intrahepatic accumulation of bile acids (BAs), resulting in liver injury, fibrosis, and liver failure. To date, only ursodeoxycholic acid and obeticholic acid have been approved for the treatment of cholestasis. As fluorofenidone (AKF-PD) was previously reported to play significant anti-fibrotic and anti-inflammatory roles in various diseases, we investigated whether AKF-PD ameliorates cholestasis. A mouse model of cholestasis was constructed by administering a 0.1 % 3,5-diethoxycarbonyl-1,4-dihydroxychollidine (DDC) diet for 14 days. Male C57BL/6 J mice were treated with either AKF-PD or pirfenidone (PD) orally in addition to the DDC diet. Serum and liver tissues were subsequently collected and analyzed. We found that AKF-PD significantly reduced the levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and total bile salts (TBA), as well as hepatic bile acids (BAs) levels. Hepatic histological analyses demonstrated that AKF-PD markedly attenuated hepatic inflammation and fibrosis. Further mechanistic analyses revealed that AKF-PD markedly inhibited expression of Cyp7a1, an enzyme key to BAs synthesis, by increasing Fxr nuclear translocation, and decreased hepatic inflammation by attenuating Erk/-Egr-1-mediated expression of inflammatory cytokines and chemokines Tnfα, Il-1β, Il-6, Ccl2, Ccl5 and Cxcl10. Moreover, AKF-PD was found to substantially reduce liver fibrosis via inhibition of Tgfβ1/Smad pathway in our mouse model. Here, we found that AKF-PD effectively attenuates cholestasis and hepatic fibrosis in the mouse model of DDC-induced cholestasis. As such, AKF-PD warrants further investigation as a candidate drug for treatment of cholestasis.

The prognostic value of antibodies to gp210 among patients with primary biliary cholangitis in Northeast China

BACKGROUND

Whether the anti-gp210 antibody can be used as a biomarker in patients with primary biliary cholangitis (PBC) remains controversial.

AIMS

We aimed to investigate the association between anti-gp210 antibodies and prognosis in ursodeoxycholic acid (UDCA)-treated PBC patients.

METHODS

We conducted a retrospective cohort study of 180 UDCA-treated PBC patients to assess the prognostic value of anti-gp210 antibodies using the Kaplan-Meier method and Cox proportional hazard regression analysis.

RESULTS

Of the patients included in our analysis, 50 (27.8%) were anti-gp210 positive, and 130 (72.2%) were anti-gp210 negative. The incidence of liver-related death or transplantation was more common in the anti-gp210 + group (22.0 vs. 9.2%, P=0.022). The five-year transplant-free survival rates of anti-gp210-positive patients vs. anti-gp210-negative patients were 77.0% and 90.3%, respectively. We found that the probability of transplant-free survival was significantly lower in the anti-gp210-positive patients than in the anti-gp210-negative patients (log-rank P=0.004). After adjusting for potential confounders using multivariable Cox regression model, positivity for anti-gp210 antibody (hazard ratio: 4.619, 95% confidence interval: 1.895-11.261, P=0.001) was found to be independently associated with an increase in liver-related mortality or transplantation.

CONCLUSION

In this cohort of UDCA-treated PBC patients, positivity for anti-gp210 antibody was independently associated with a higher risk of liver-related death or transplantation.

Oleanolic acid alleviates ANIT-induced cholestatic liver injury by activating Fxr and Nrf2 pathways to ameliorate disordered bile acids homeostasis

BACKGROUND

Cholestasis is a clinical syndrome with high incidence and few effective treatments. Oleanolic acid (OA) is a triterpenoid compound with anti-cholestatic effects. Studies using bile duct ligation or lithocholic acid modeling have shown that the alleviating effect of OA on cholerosis is related to the regulation of nuclear factor erythroid 2 related factor (Nrf2) or farnesoid X receptor (Fxr).

PURPOSE

This study aims to investigate the underlying mechanism of OA against alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury based on Nrf2 and Fxr dual signaling pathways.

METHODS

The ANIT-induced rats model was used with or without OA treatment. Serum biochemical indexes, liver histopathological changes and glutathione level were examined. Bile acids (BAs) targeted metabolomics based on UHPLC-MS/MS were performed. siRNA, RT-qPCR and western blot analysis were used to prove the role of Fxr and Nrf2 pathway in OA's anti-cholestatic liver injury in vivo and in vitro.

RESULTS

OA significantly alleviated ANIT-induced liver injury in rats, reduced primary bile acids, accelerated metabolism of BAs and reduced the intrahepatic accumulation of BAs. The expressions of bile salt export pump (Bsep), Na+-taurocholic cotransport polypeptide (Ntcp), UDP-glucuronyl transferase 1a1 (Ugt1a1) and Fxr in rat liver were markedly up-regulated, the activation of Nrf2 was promoted, and the expression of cholesterol 7α-hydroxylase (Cyp7a1) was decreased after OA treatment. Moreover, Fxr or Nrf2 silencing attenuated the regulation of OA on BAs homeostasis related transporters and enzymes in rat primary hepatocytes.

CONCLUSION

OA may regulate BAs-related transporters and metabolic enzymes by activating Fxr and Nrf2 pathways, thus alleviating the cholestatic liver injury induced by ANIT.

Hepatoprotective Effects of Glycyrrhetinic Acid on Lithocholic Acid-Induced Cholestatic Liver Injury Through Choleretic and Anti-Inflammatory Mechanisms

Cholestasis is a clinical syndrome triggered by the accumulation and aggregation of bile acids by subsequent inflammatory responses. The present study investigated the protective effect of glycyrrhetinic acid (GA) on the cholestatic liver injury induced by lithocholic acid (LCA) from both anti-inflammatory and choleretic mechanistic standpoints. Male C57BL/6 mice were treated with LCA twice daily for 4 days to induce intrahepatic cholestasis. GA (50 mg/kg) and pregnenolone 16α-carbonitrile (PCN, 45 mg/kg) were intraperitoneally injected 3 days before and throughout the administration of LCA, respectively. Plasma biochemical indexes were determined by assay kits, and hepatic bile acids were quantified by LC-MS/MS. Hematoxylin and eosin staining of liver sections was performed for pathological examination. Protein expression of the TLRs/NF-κB pathway and the mRNA levels of inflammatory cytokines and chemokines were examined by Western blotting and PCR, respectively. Finally, the hepatic expression of pregnane X receptor (PXR) and farnesoid X receptor (FXR) and their target genes encoding metabolic enzymes and transporters was evaluated. GA significantly reversed liver necrosis and decreased plasma ALT and ALP activity. Plasma total bile acids, total bilirubin, and hepatic bile acids were also remarkably preserved. More importantly, the recruitment of inflammatory cells to hepatic sinusoids was alleviated. Additionally, the protein expression of TLR2, TLR4, and p-NF-κBp65 and the mRNA expression of CCL2, CXCL2, IL-1β, IL-6, and TNF-α were significantly decreased. Moreover, GA significantly increased the expression of hepatic FXR and its target genes, including BSEP, MRP3, and MRP4. In conclusion, GA protects against LCA-induced cholestatic liver injury by inhibiting the TLR2/NF-κB pathway and upregulating hepatic FXR expression.

Gut microbiota-derived bile acids in intestinal immunity, inflammation, and tumorigenesis

Inflammatory bowel disease (IBD) and colorectal cancer (CRC) are heterogeneous intestinal diseases that threaten the health of an increasing number of individuals as their lifestyles become westernized. New insights have been discovered with the development of various omics techniques, revealing that gut-microbiota-derived metabolites play important roles in maintaining intestinal homeostasis and modulating the progression of intestinal diseases from both metabolic and immunological perspectives. Clinical metagenomic and metabolomic studies have revealed links between microbial bile acid (BA) metabolism and IBD and CRC progression. Several BA-derived metabolites were recently been demonstrated to play a role in intestinal immunity, providing fresh insights into how BAs affect the course of IBD and CRC. In this review, we discuss recent studies on the involvement of gut microbiota-derived BAs in intestinal immunity, inflammation, and tumorigenesis along with human omics data to provide prospective insights into future prevention and treatment of IBD and CRC.

Arbutin Alleviates the Liver Injury of α-Naphthylisothiocyanate-induced Cholestasis Through Farnesoid X Receptor Activation

Cholestasis is a kind of stressful syndrome along with liver toxicity, which has been demonstrated to be related to fibrosis, cirrhosis, even cholangiocellular or hepatocellular carcinomas. Cholestasis usually caused by the dysregulated metabolism of bile acids that possess high cellular toxicity and synthesized by cholesterol in the liver to undergo enterohepatic circulation. In cholestasis, the accumulation of bile acids in the liver causes biliary and hepatocyte injury, oxidative stress, and inflammation. The farnesoid X receptor (FXR) is regarded as a bile acid–activated receptor that regulates a network of genes involved in bile acid metabolism, providing a new therapeutic target to treat cholestatic diseases. Arbutin is a glycosylated hydroquinone isolated from medicinal plants in the genus Arctostaphylos, which has a variety of potentially pharmacological properties, such as anti-inflammatory, antihyperlipidemic, antiviral, antihyperglycemic, and antioxidant activity. However, the mechanistic contributions of arbutin to alleviate liver injury of cholestasis, especially its role on bile acid homeostasis via nuclear receptors, have not been fully elucidated. In this study, we demonstrate that arbutin has a protective effect on α-naphthylisothiocyanate–induced cholestasis via upregulation of the levels of FXR and downstream enzymes associated with bile acid homeostasis such as Bsep, Ntcp, and Sult2a1, as well as Ugt1a1. Furthermore, the regulation of these functional proteins related to bile acid homeostasis by arbutin could be alleviated by FXR silencing in L-02 cells. In conclusion, a protective effect could be supported by arbutin to alleviate ANIT-induced cholestatic liver toxicity, which was partly through the FXR pathway, suggesting arbutin may be a potential chemical molecule for the cholestatic disease.

Bile Acid Dysregulation Is Intrinsically Related to Cachexia in Tumor-Bearing Mice

Simple Summary

Cancer cachexia is considered a multi-organ syndrome. An improved understanding of how circulating molecules can affect tissues and mediate their crosstalk in the pathogenesis of cancer cachexia is emerging. Considering the various actions of bile acids on host metabolism and immunity, they could represent innovative targets in cancer cachexia. In this study, we investigated how bile acids could contribute to this syndrome by assessing the bile flow, by comparing the impact on bile acid pathways of cachexia-inducing and non-cachexia-inducing cell sublines, and by investigating the effects of ursodeoxycholic acid, a choleretic compound, in cachectic mice. Altogether, our analyses strengthen the importance of bile acids and their receptors as key players in the metabolic disorders associated with cancer, thereby laying the foundation for new therapeutic opportunities.

Abstract

Bile acids exert diverse actions on host metabolism and immunity through bile acid-activated receptors, including Takeda G protein-coupled receptor 5 (TGR5). We have recently evidenced an alteration in bile acids in cancer cachexia, an inflammatory and metabolic syndrome contributing to cancer death. This current study aims to further explore the links emerging between bile acids and cancer cachexia. First, we showed that bile flow is reduced in cachectic mice. Next, comparing mice inoculated with cachexia-inducing and with non-cachexia-inducing C26 colon carcinoma cells, we demonstrated that alterations in the bile acid pathways and profile are directly associated with cachexia. Finally, we performed an interventional study using ursodeoxycholic acid (UDCA), a compound commonly used in hepatobiliary disorders, to induce bile acid secretion and decrease inflammation. We found that UDCA does not improve hepatic inflammation and worsens muscle atrophy in cachectic mice. This exacerbation of the cachectic phenotype upon UDCA was accompanied by a decreased TGR5 activity, suggesting that TGR5 agonists, known to reduce inflammation in several pathological conditions, could potentially counteract cachectic features. This work brings to light major evidence sustaining the emerging links between bile acids and cancer cachexia and reinforces the interest in studying bile acid-activated receptors in this context.

Pterostilbene Alleviates Cholestasis by Promoting SIRT1 Activity in Hepatocytes and Macrophages

Background and purpose: FXR is a promising target for the treatment of human cholestatic liver disease (CLD). SIRT1 is a deacetylase which promotes FXR activity through deacetylating FXR. Pterostilbene (PTE) is an activator of SIRT1. However, the role of PTE in cholestasis has so far not been investigated. We examined whether PTE treatment alleviate liver injury in DDC or ANIT-induced experimental cholestasis, and explored the underlying mechanisms. Experimental approach: Mice with DDC- or ANIT-induced cholestasis were treated with different dose of PTE. Primary hepatocytes and bone marrow derived macrophages were used in vitro to assess the molecular mechanism by which PTE may improve CLD. Identical doses of UDCA or PTE were administered to DDC- or ANIT-induced cholestasis mice. Key results: PTE intervention attenuated DDC or ANIT-induced cholestasis. PTE inhibited macrophage infiltration and activation in mouse liver through the SIRT1-p53 signaling pathway, and it improved hepatic bile metabolism through the SIRT1-FXR signaling pathway. Compare with UDCA, the same doses of PTE was more effective in improving cholestatic liver injury caused by DDC or ANIT. Conclusion and implications: SIRT1 activation in macrophages may be an effective CLD treatment avenue. Using CLD models, we thus identified PTE as a novel clinical candidate compound for the treatment of CLD.

Detection of anti-kelch-like 12 and anti-hexokinase 1 antibodies in primary biliary cholangitis patients in China

OBJECTIVES

primary biliary cholangitis (PBC) is a chronic cholestatic disease, characterized by positive anti-mitochondrial autoantibodies (AMA) in 90-95 % patients. Anti-kelch-like 12 (anti-KLHL12) and anti-hexokinase1 (anti-HK1) antibodies have been identified as the two new serum markers in recent years, which are used in the diagnosis of AMA-negative PBC patients. The objective of the study was to examine the performance of these two new biomarkers in China.

METHODS

a total of 192 patients were enrolled and screened for anti-KLHL12 and anti-HK1 antibodies and AMA by ELISA. Receiver operating characteristic (ROC curve) analysis was applied to examine the diagnostic importance of AMA, anti-KLHL12 and anti-HK1 antibodies. Furthermore, correlation analysis between some important biochemical indexes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase [ALP], bilirubin, gamma-glutamil transferasa [γ-GT]), staging of pathological changes of the liver and the expression of novel antibodies in PBC patients were also examined.

RESULTS

the positivity of the anti-HK1 antibody in AMA-positive PBC patients and AMA-negative patients was 44.7 % and 33.3 %, respectively. The specificity, proportion of positive patients (PPV) and proportion of negative patients (NPV) were 93 %, 89 % and 53 %, respectively. In contrast, the positivity to the anti-KLHL12 antibody in AMA-positive and negative PBC patients was 41.2 % and 22.2 %, respectively. Specificity, PPV and NPV were 98 %, 95 % and 52 %, respectively. The area under the curve (AUC) with anti-HK1 and anti-KLHL12 antibodies were 0.720 and 0.703. With the combination with anti-HK1 and anti-KLHL12 antibodies, the AUC of AMA increased from 0.889 to 0.891, increasing the sensitivity from 0.764 to 0.836. Anti-KLHL12 and anti-HK1-positive patients had higher serum levels of ALP, γ-GT and bilirubin, with statistically significant differences (p < 0.01) compared with anti-KLHL12 or anti-HK1-negative patients. Notably, correlation analysis showed a significant positive correlation between antibody expression and ALP, γ-GT and bilirubin serum levels (r = 0.735, 0.491, 0.466; p < 0.01).

CONCLUSIONS

anti-HK1 and anti-KLHL12 antibodies have been identified as two significant biomarkers in PBC patients. Furthermore, the presence of these antibodies is likely to correlate with the severity of PBC.

Omega-3 Polyunsaturated Fatty Acid: A Pharmaco-Nutraceutical Approach to Improve the Responsiveness to Ursodeoxycholic Acid

Ursodeoxycholic acid (UDCA) is the first line therapy for the treatment of cholestatic and autoimmune liver diseases. Its clinical use is currently limited by a significant proportion of non-responder patients. Polyunsaturated fatty acids (n-3 PUFAs) possess important anti-inflammatory properties and protect liver cells against bile acid (BA)-induced toxicity. The present study was designed to rapidly evaluate whether combining n-3 PUFAs (i.e., eicosapentaenoic [EPA] and docosahexaenoic [DHA] acids) to UDCA would provide additional benefits when compared to the drug alone. The parameters evaluated were (i) the expression of genes governing BA synthesis, transport, and metabolism; (ii) the prevention of BA-induced apoptosis and endoplasmic reticulum (ER)-stress; and (iii) the control of BA- and LPS-dependent inflammation. In the absence of n-3 PUFAs, most of the parameters investigated were unaffected by UDCA or were only altered by the higher dose (500 µM) of the drug. By contrast, in the presence of EPA/DHA (50/50 µM), all parameters showed a strongly improved response and the lowest UDCA dosage (50 µM) provided equal or better benefits than the highest dose used alone. For example, the combination EPA/DHA + UDCA 50 µM caused comparable down-regulation of the CYP7A1 gene expression and of the BA-induced caspase 3 activity as observed with UDCA 500 µM. In conclusion, these results suggest that the addition of n-3 PUFAs to UDCA may improve the response to the drug, and that such a pharmaco-nutraceutical approach could be used in clinic to open the narrow therapeutic dose of UDCA in cholestatic liver diseases.

Clinical Management of Primary Biliary Cholangitis-Strategies and Evolving Trends

PBC is a chronic progressive autoimmune disorder involving the destruction of intrahepatic small bile ducts, cholestasis, fibrosis, and ultimately cirrhosis if left untreated. It is largely driven by the autoimmune response, but bile acids and the intestinal microbiota are implicated in disease progression as well. The only drugs licensed for PBC are UDCA and OCA. UDCA as a first-line and OCA as a second-line therapy are safe and effective, but the lack of response in a significant portion of patients and inadequate control of symptoms such as fatigue and pruritus remain as concerns. Liver transplantation is an end-stage therapy for many patients refractory to UDCA, which gives excellent survival rates but also moderate to high recurrence rates. The limited options for FDA-approved PBC therapies necessitate the development of alternative approaches. Currently, a wide variety of experimental drugs exist targeting immunological and physiological aspects of PBC to suppress inflammation. Immunological therapies include drugs targeting immune molecules in the B cell and T cell response, and specific cytokines and chemokines implicated in inflammation. Drugs targeting bile acids are also noteworthy as bile acids can perpetuate hepatic inflammation and lead to fibrosis over time. These include FXR agonists, ASBT inhibitors, and PPAR agonists such as bezafibrate and fenofibrate. Nonetheless, many of these drugs can only delay disease progression and fail to enhance patients' quality of life. Nanomedicine shows great potential for treatment of autoimmune diseases, as it provides a new approach that focuses on tolerance induction rather than immunosuppression. Tolerogenic nanoparticles carrying immune-modifying agents can be engineered to safely and effectively target the antigen-specific immune response in autoimmune diseases. These may work well with PBC especially, given the anatomical features and immunological specificity of the disease. Nanobiological therapy is thus an area of highly promising research for future treatment of PBC.

Autoimmune biliary diseases: primary biliary cholangitis and primary sclerosing cholangitis

Autoimmune cholestatic liver diseases are rare hepato-biliary disorders characterized by a progressive, inflammatory destruction of bile ducts. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are the main autoimmune cholestatic liver diseases. Both may evolve into secondary biliary cirrhosis and its complications. Therapeutic options are limited and liver transplantation remains the only definitive treatment for PBC and PSC.

Most PBC and PSC patients have a typical presentation, which does not require liver biopsy. However, in routine clinical practice, important variants or specific subgroups that benefit from liver biopsy for proper management may be observed. Herein, we provide a general overview of clinical and pathological characteristic of PBC and PSC, highlighting the most important features for routine diagnostic practice.

Kinsenoside Alleviates 17α-Ethinylestradiol-Induced Cholestatic Liver Injury in Rats by Inhibiting Inflammatory Responses and Regulating FXR-Mediated Bile Acid Homeostasis

Cholestasis is an important predisposing factor of liver diseases, such as hepatocyte necrosis, liver fibrosis and primary biliary cirrhosis. In this study, we aimed to investigate the effects of Kinsenoside (KD), a natural active ingredient of Anoectochilus roxburghii, on estrogen-induced cholestatic liver injury in Sprague-Dawley rats and the underlying mechanism. The rats were randomly divided into six groups: control group, model group, low-dose KD group (50 mg/kg body weight, KD-L), medium-dose KD group (100 mg/kg body weight, KD-M), high-dose KD group (200 mg/kg body weight, KD-H) and ursodeoxycholic acid group (40 mg/kg body weight, UDCA). 17α-Ethinylestradiol (EE) was used to establish an experimental animal model of estrogen-induced cholestasis (EIC). The results demonstrated that KD alleviated liver pathologic damage, serum biochemical status and inhibited hepatocellular microstructure disorder and bile duct hyperplasia in EE-induced cholestatic rats. Mechanically, KD alleviated EE-induced cholestatic liver injury by inhibiting inflammatory responses and regulating bile acid homeostasis. Concretely, KD reduced the expression of IL-1β and IL-6 by inhibiting NF-κB p65 to suppress EE-mediated inflammation in rat liver. KD enhanced the expression of FXR and inhibited EE-mediated reduction of FXR in vitro and in vivo. It was the potential mechanism that KD mitigates cholestasis by increasing efflux and inhibiting uptake of bile acids via FXR-mediated induction of bile salt export pump (BSEP) and reduction of Na⁺-dependent taurocholate cotransport peptide (NTCP) to maintain bile acid homeostasis. Moreover, KD repressed the bile acid synthesis through reducing the expression of synthetic enzyme (CYP7A1), thereby normalizing the expression of metabolic enzyme (SULT2A1) of bile acid. In conclusion, our results revealed that KD may be an effective drug candidate for the treatment of cholestasis.

The role of farnesoid X receptor in metabolic diseases, and gastrointestinal and liver cancer

Farnesoid X receptor (FXR) is a ligand-activated transcription factor involved in the control of bile acid (BA) synthesis and enterohepatic circulation. FXR can influence glucose and lipid homeostasis. Hepatic FXR activation by obeticholic acid is currently used to treat primary biliary cholangitis. Late-stage clinical trials investigating the use of obeticholic acid in the treatment of nonalcoholic steatohepatitis are underway. Mouse models of metabolic disease have demonstrated that inhibition of intestinal FXR signalling reduces obesity, insulin resistance and fatty liver disease by modulation of hepatic and gut bacteria-mediated BA metabolism, and intestinal ceramide synthesis. FXR also has a role in the pathogenesis of gastrointestinal and liver cancers. Studies using tissue-specific and global Fxr-null mice have revealed that FXR acts as a suppressor of hepatocellular carcinoma, mainly through regulating BA homeostasis. Loss of whole-body FXR potentiates progression of spontaneous colorectal cancer, and obesity-induced BA imbalance promotes intestinal stem cell proliferation by suppressing intestinal FXR in Apc^min/+ mice. Owing to altered gut microbiota and FXR signalling, changes in overall BA levels and specific BA metabolites probably contribute to enterohepatic tumorigenesis. Modulating intestinal FXR signalling and altering BA metabolites are potential strategies for gastrointestinal and liver cancer prevention and treatment. In this Review, studies on the role of FXR in metabolic diseases and gastrointestinal and liver cancer are discussed, and the potential for development of targeted drugs are summarized.

The Management of Cholestatic Liver Diseases: Current Therapies and Emerging New Possibilities

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are two chronic cholestatic liver diseases affecting bile ducts that may progress to biliary cirrhosis. In the past few years, the increasing knowledge in the pathogenesis of both diseases led to a growing number of clinical trials and possible new targets for therapy. In this review, we provide an update on the treatments in clinical use and summarize the new drugs in trials for PBC and PSC patients. Farnesoid X Receptor (FXR) agonists and Pan-Peroxisome Proliferator-Activated Receptor (PPAR) agonists are the most promising agents and have shown promising results in both PBC and PSC. Fibroblast Growth Factor 19 (FGF19) analogues also showed good results, especially in PBC, while, although PBC and PSC are autoimmune diseases, immunosuppressive drugs had disappointing effects. Since the gut microbiome could have a potential role in the pathogenesis of PSC, recent research focused on molecules that could change the microbiome, with good results. The near future of the medical management of these diseases may include new treatments or a combination of multiple drugs targeting different signaling pathways at different stages of the diseases.

Pharmacological properties of baicalin on liver diseases: a narrative review

Baicalin is the main active component of Scutellaria baicalensis, widely used in traditional Chinese medicine thanks to its various pharmacological effects, such as anti-tumor, anti-inflammatory, and antibacterial properties, as well as cardiovascular, hepatic, and renal protective effect. Recently, the protective effects of baicalin on liver disease have received much more attention. Several studies showed that baicalin protects against several types of liver diseases including viral hepatitis, fatty liver disease, xenobiotic induced liver injury, cholestatic liver injury, and hepatocellular carcinoma, with a variety of pharmacological mechanisms. A comprehensive understanding of the mechanism of baicalin can provide a valuable reference for its clinical use, but up to now, no narrative review is available that summarizes the pharmacological effects of baicalin to clarify its potential use in the treatment of liver diseases. Therefore, this review summarizes the progress of baicalin research and the underlying mechanism in the treatment of various liver diseases, to promote further research and its clinical application.

The association of histological progression with biochemical response to ursodeoxycholic acid in primary biliary cholangitis

Primary biliary cholangitis (PBC) is currently diagnosed at an early stage; therefore, the number of patients with PBC without symptoms at the time of diagnosis is increasing. However, up to 30% of patients with PBC exhibit the suboptimal response to ursodeoxycholic acid (UDCA) and are at high risk of end-stage liver disease. Obeticholic acid is an approved second-line therapy for patients with PBC that are refractory to UDCA. Novel surrogate endpoints are required to identify individuals eligible for second-line therapies. An inadequate biochemical response to UDCA is a useful predictor of poor outcomes in patients with PBC. In addition to UDCA effects on biochemical parameters, histological outcomes could be considered as candidate surrogate endpoints. Alterations in liver histology are used as surrogate endpoints in clinical studies. However, current staging systems are insufficient to determine PBC disease severity and progression because of the pathological heterogeneity of the disease. Histological features at baseline and biochemical response to UDCA treatment can affect the disease course of PBC. Therefore, novel surrogate endpoints must be represented by parameters characterized by histological outcomes and treatment responses in PBC. In this review, we discuss the existing histological parameters and newly created factors to identify patients with PBC who are at a high risk of developing end-stage liver disease and, consequently, the potential need for additional treatments.

Syphilis Hepatitis Presenting as a Mimic of Primary Biliary Cholangitis

Syphilis hepatitis is a rare cause of acute liver injury. Primary biliary cholangitis (PBC) is a progressive autoimmune disease characterized by the typical presentation of a cholestatic liver injury and the presence of antimitochondrial antibodies (AMAs). We present a case of syphilis hepatitis that presented as a mimic to PBC with positive AMA. The eradication of syphilis led to the resolution of the liver injury and down trending of the antibody level. We recommend excluding syphilis in patients with high-risk behaviors presenting with a cholestatic liver injury and positive AMA before the diagnosis of PBC.

Clinical Updates in Primary Biliary Cholangitis: Trends, Epidemiology, Diagnostics, and New Therapeutic Approaches

Primary biliary cholangitis, formerly known as primary biliary cirrhosis, is a chronic, autoimmune, and cholestatic disease ameliorating the biliary epithelial system causing fibrosis and end-stage liver disease, over time. Patients range from an asymptomatic phase early in the disease course, to symptoms of decompensated cirrhosis later in its course. This review focuses on the current consensus on the epidemiology, diagnosis, and management of patients with primary biliary cholangitis. We also discuss established medical management as well as novel and investigational therapeutics in the pipeline for management of PBC.

Race/Ethnicity and Insurance-Specific Disparities in In-Hospital Mortality Among Adults with Primary Biliary Cholangitis: Analysis of 2007-2014 National Inpatient Sample

BACKGROUND

Primary biliary cholangitis (PBC) is a progressive autoimmune liver disease that can result in cirrhosis and end-stage liver disease.

AIMS

We aim to evaluate hospitalization burden and in-hospital mortality among PBC patients in the USA.

METHODS

Using data from the Nationwide Inpatient Sample from 2007 to 2014, hospitalizations among US adults with PBC were stratified by sex, age, and race/ethnicity. Overall in-hospital mortality was stratified by these variables and adjusted multivariate regression models evaluated for predictors of in-hospital mortality.

RESULTS

From 2007 to 2014, there were 18,279 hospitalizations among adults with PBC (15.0% male, mean age 63.8 years, 41.3% cirrhosis). Among non-Hispanic whites, the proportion of total PBC hospitalizations increased from 57.8% in 2007 to 71.2% in 2014, compared to 4.1-6.3% for African-Americans, 8.6-10.9% for Hispanics, and 1.7-2.8% for Asians (p < 0.001 for all). While overall in-hospital mortality was low (4.2%), increasing age was associated with higher odds of in-hospital mortality (OR: 1.02, 95% CI 1.01-1.03, p < 0.001). Compared to non-Hispanic white PBC patients, higher in-hospital mortality was observed in African-American PBC patients (OR: 1.40, 95% CI 1.16-2.03, p < 0.05). Compared to patients with private/commercial insurance, significantly higher odds of in-hospital mortality were observed in patients with Medicaid insurance (OR 1.42, 95% CI 1.00-1.99, p < 0.05).

CONCLUSION

In summary, among adults with PBC hospitalized in the USA from 2007 to 2014, the overall number of hospitalizations is increasing. Significant disparities in in-hospital mortality were observed; African-Americans with PBC and Medicaid patients with PBC have disproportionately higher odds of in-hospital mortality.

Bile Acid Receptor Therapeutics Effects on Chronic Liver Diseases

In the past ten years, our understanding of the importance of bile acids has expanded from fat absorption and glucose/lipid/energy homeostasis into potential therapeutic targets for amelioration of chronic cholestatic liver diseases. The discovery of important bile acid signaling mechanisms, as well as their role in metabolism, has increased the interest in bile acid/bile acid receptor research development. Bile acid levels and speciation are dysregulated during liver injury/damage resulting in cytotoxicity, inflammation, and fibrosis. An increasing focus to target bile acid receptors, responsible for bile acid synthesis and circulation, such as Farnesoid X receptor and apical sodium-dependent bile acid transporter to reduce bile acid synthesis have resulted in clinical trials for treatment of previously untreatable chronic liver diseases such as non-alcoholic steatohepatitis and primary sclerosing cholangitis. This review focuses on current bile acid receptor mediators and their effects on parenchymal and non-parenchymal cells. Attention will also be brought to the gut/liver axis during chronic liver damage and its treatment with bile acid receptor modulators. Overall, these studies lend evidence to the importance of bile acids and their receptors on liver disease establishment and progression.

Factors Associated With Potential Progressive Course of Primary Biliary Cholangitis: Data From Real-world US Database

BACKGROUND AND AIMS

Although relatively, primary biliary cholangitis (PBC) is an important cause of nonalcoholic chronic liver disease which may lead to liver transplantation. PBC patients with alkaline phosphatase (ALP) ≥1.5× the upper limit of normal (ULN) tend to have a more aggressive course. The study was designed to identify factors associated with ALP≥1.5×ULN or cirrhosis in PBC and to evaluate concomitant health care resource utilization.

METHODS

We used a large real-world database that contained comprehensive and continuous electronic medical recored/claims data from over 500 health care practices or systems from the United States.

RESULTS

Of 195 million patients included in the database, 36,317 were adults with PBC. After applying exclusion criteria, 15,875 patients comprised the final PBC cohort (63.0±13.5 y, 78% female, 71% privately insured, 5% covered by Medicaid, 57% with other autoimmune diseases, 46% with cirrhosis); 6083 (38%) had ALP≥1.5×ULN. Patients with ALP≥1.5×ULN were more frequently female, less covered by Medicaid, had more pruritus, cirrhosis, and other autoimmune diseases (P<0.05). In multivariate analysis, older age, female gender, the presence of other autoimmune diseases, and having compensated or decompensated cirrhosis were independently associated with having ALP≥1.5×ULN in PBC (P<0.05). In contrast, being male was associated with higher risk of cirrhosis in PBC [odds ratio 2.3 (95% confidence interval, 2.1-2.5)]. Patients with ALP≥1.5×ULN and/or with cirrhosis also incurred substantially more health care resource utilization (P<0.05).

CONCLUSIONS

Many clinical, sociodemographic, and economic factors are associated with a potentially more aggressive profile of PBC with elevated ALP. These data may inform clinicians to implement management strategies to optimize care of these patients.

Epidemiology and clinical course of primary biliary cholangitis in the Asia-Pacific region: a systematic review and meta-analysis

AIMS

Epidemiological studies on primary biliary cholangitis (PBC) show heterogeneity. The aim of the present study was to synthesize the prevalence, incidence and clinical course of PBC in the Asia-Pacific region.

METHODS

PubMed, Medline, Cochrane library and EMBASE were searched for epidemiology and clinical course of PBC published up to July, 2019. Meta-analysis was conducted on the epidemiology and clinical course (decompensation, hepatocellular carcinoma and death/liver transplantation) of PBC patients. Random-effect model and fixed-effect model were used to evaluate the pooled prevalence, incidence, mortality/liver transplantation and their 95% confidence intervals as appropriate. Subgroup analysis was performed by stratification with gender, pre- and post-UDCA era, sub-region and publication year. Meta-regression was used to examine the heterogeneity.

RESULTS

Out of 3460 studies, 18 studies from 7 countries/regions were finally included. The overall prevalence of PBC was 118.75 cases per million (95% CI 49.96-187.55) in the Asia-Pacific region, with the high, medium and low prevalence being in Japan and China (191.18 cases per million), New Zealand (99.16 cases per million) and South Korea and Australia (39.09 cases per million), respectively. The incidence of PBC was 8.55 cases per million per year (95% CI 8.05-9.06). The 5-year accumulative incidence of decompensation, HCC and death/liver transplantation in PBC patients was 6.95% (95% CI 2.07-11.83%), 1.54% (95% CI 0.9-2.19%) and 4.02% (95% CI 2.49-5.54%), respectively.

CONCLUSION

In the Asia-Pacific region, the prevalence and incidence of PBC are higher than once expected. PBC tends to be diagnosed at older age and has a relatively low incidence of HCC in this region.

Synthesis and characterization of new impurities in obeticholic acid

Novel and efficient synthetic strategies are developed for the first synthesis of two new impurities found in obeticholic acid. The synthetic routes to the impurities are designed without column purification using 4-nitrobenzoyl chloride as a selective protecting group. The impurities, which are obtained in good yields and high purity, are identified and characterized using high-resolution mass spectrometry, Fourier transform infrared, one-dimensional nuclear magnetic resonance (1H, 13C, distortionless enhancement by polarization transfer), and two-dimensional nuclear magnetic resonance (Correlated Spectroscopy, heteronuclear single quantum coherence, heteronuclear multiple bond correlation, and rotating-frame Overhauser effect spectroscopy) techniques.

Primary Biliary Cholangitis in Medicare Population: The Impact on Mortality and Resource Use

Primary biliary cholangitis (PBC) is a disease of small bile ducts, which can lead to morbidity and mortality. Our aim was to assess recent trends in mortality and healthcare use of PBC patients in the Medicare program. Data from Medicare beneficiaries between 2005 and 2015 (5% random samples) were used. The diagnosis of PBC was established with International Classification of Diseases-9 code 571.6 used for both primary and secondary diagnoses. Mortality was assessed by Medicare-linked death registry. Healthcare use included episodes of care, length of stay, and total charges/payments. Independent predictors of outcomes were evaluated in multiple generalized linear or logistic regression models. The study cohort included a total of 6,375 inpatient/outpatient Medicare beneficiaries (mean age 69.8 years, 17% male, 88% white, and 18% with disability). Over the study period, 1-year mortality remained stable (9.1% to 14.3%, P = 0.11). Independent predictors of 1-year mortality were older age, male gender, black race, the presence of ascites, encephalopathy, hepatocellular carcinoma, and higher Charlson score. Outpatient total yearly charges and payments per beneficiary with PBC increased from $3,065 and $777 (2005) to $5,773 and $967 (2014), respectively. Similarly, inpatient total yearly charges and payments per beneficiary with PBC increased from $59,765 and $19,406 (2007), to $98,941 and $27,948 (2013), respectively (P < 0.05). The presence of ascites, portal hypertension, and higher Charlson score were independent predictors of higher payments for both inpatient and outpatient resource use, and the presence of hepatic encephalopathy was an additional predictor of higher inpatient resource use (all P < 0.02). Conclusion: The prevalence of PBC among the Medicare beneficiaries has increased. Despite stable mortality rates, resource use for Medicare patients with PBC continues to rise.

Novel and emerging therapies for cholestatic liver diseases

While bile acids are important for both digestion and signalling, hydrophobic bile acids can be harmful, especially when in high concentrations. Mechanisms for the protection of cholangiocytes against bile acid cytotoxicity include negative feedback loops via farnesoid X nuclear receptor (FXR) activation, the bicarbonate umbrella, cholehepatic shunting and anti-inflammatory signalling, among others. By altering or overwhelming these defence mechanisms, cholestatic diseases such as primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) can further progress to biliary cirrhosis, end-stage liver disease and death or liver transplantation. While PBC is currently treated with ursodeoxycholic acid (UDCA) and obeticholic acid (OCA), many fail treatment, and we have yet to find an effective therapy for PSC. Novel therapies under evaluation target nuclear and surface receptors including FXR, transmembrane G-protein-coupled receptor 5 (TGR5), peroxisome proliferator-activated receptor (PPAR) and pregnane X receptor (PXR). Modulation of these receptors leads to altered bile composition, decreased cytotoxicity, decreased inflammation and improved metabolism. This review summarizes our current understanding of the role of bile acids in the pathophysiology of cholestatic liver diseases, presents the rationale for already approved medical therapies and discusses novel pharmacologic therapies under investigation.

Cholestatic liver diseases: new targets, new therapies

Cholestatic liver diseases result from gradual destruction of bile ducts, accumulation of bile acids and self-perpetuation of the inflammatory process leading to damage to cholangiocytes and hepatocytes. If left untreated, cholestasis will lead to fibrosis, biliary cirrhosis, and ultimately end-stage liver disease. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are the two most common chronic cholestatic liver diseases affecting adults, and their etiologies remain puzzling. While treatment with ursodeoxycholic acid (UDCA) has significantly improved outcomes and prolonged transplant-free survival for patients with PBC, treatment options for UDCA nonresponders remain limited. Furthermore, there is no available medical therapy for PSC. With recent advances in molecular biochemistry specifically related to bile acid regulation and understanding of immunologic pathways, novel pharmacologic treatments have emerged. In this review, we discuss the standard of care and emphasize the various emerging treatments for PBC and PSC.

In Silico Workflow for the Discovery of Natural Products Activating the G Protein-Coupled Bile Acid Receptor 1

The G protein-coupled bile acid receptor (GPBAR1) has been recognized as a promising new target for the treatment of diverse diseases, including obesity, type 2 diabetes, fatty liver disease and atherosclerosis. The identification of novel and potent GPBAR1 agonists is highly relevant, as these diseases are on the rise and pharmacological unmet therapeutic needs are pervasive. Therefore, the aim of this study was to develop a proficient workflow for the in silico prediction of GPBAR1 activating compounds, primarily from natural sources. A protocol was set up, starting with a comprehensive collection of structural information of known ligands. This information was used to generate ligand-based pharmacophore models in LigandScout 4.08 Advanced. After theoretical validation, the two most promising models, namely BAMS22 and TTM8, were employed as queries for the virtual screening of natural product and synthetic small molecule databases. Virtual hits were progressed to shape matching experiments and physicochemical clustering. Out of 33 diverse virtual hits subjected to experimental testing using a reporter gene-based assay, two natural products, farnesiferol B (27) and microlobidene (28), were confirmed as GPBAR1 activators reaching more than 50% receptor activation at 20 μM with EC50s of 13.53 μM and 13.88 μM, respectively. This activity is comparable to that of the endogenous ligand lithocholic acid (1). Seven further virtual hits showed activity reaching at least 15% receptor activation either at 5 or 20 μM, including new scaffolds from natural and synthetic origin.