Old and new treatments for primary biliary cholangitis

Dimethyl fumarate attenuates cholestatic liver injury by activating the NRF2 and FXR pathways and suppressing NLRP3/GSDMD signaling in mice

The progression of cholestasis is characterized by excessive accumulation of bile acids (BAs) in the liver, which leads to oxidative stress (OS), inflammation and liver injury. There are currently limited treatments for cholestasis. Therefore, appropriate drugs for cholestasis treatment need to be developed. Dimethyl fumarate (DMF) has been widely used in the treatment of various diseases and exerts antioxidant and anti-inflammatory effects, but its effect on cholestatic liver disease remains unclarified. We fed mice 3,5-diethoxycarbonyl-1,4-dihydrocollidine or cholic acid to induce cholestatic liver injury and treated these mice with DMF to evaluate its protective ability. Alanine aminotransferase, aspartate aminotransferase, and total liver BAs were assessed as indicators of liver function. The levels of OS, liver inflammation, transporters and metabolic enzymes were also measured. DMF markedly altered the relative ALT and AST levels and enhanced the liver antioxidant capacity. DMF regulated the MST/NRF2 signaling pathway to protect against OS and reduced liver inflammation through the NLRP3/GSDMD signaling pathway. DMF also regulated the levels of BA transporters by promoting FXR protein expression. These findings provide new strategies for the treatment of cholestatic liver disorders.

Optimization and Impurity Control Strategy for Lithocholic Acid Production Using Commercially Plant-Sourced Bisnoralcohol

In this study, lithocholic acid (LCA) was prepared using commercially available plant-sourced bisnoralcohol (BA), and the overall yield of the product was 70.6% for five steps. To prevent process-related impurities, the isomerizations of catalytic hydrogenation in the C4-C5 double bond and reduction of the 3-keto group were optimized. The double bond reduction isomerization was improved (5β-H:5α-H = 97:3) using palladium-copper nanowires (Pd-Cu NWs) instead of Pd/C. The reduction of the 3-keto group was 100% converted to a 3α-OH product by 3α-hydroxysteroid dehydrogenase/carbonyl reductase catalysis. Moreover, the impurities during the optimization process were comprehensively studied. Compared with the reported synthesis methods, our developed method significantly improved the isomer ratio and overall yield, affording ICH-grade quality of LCA, and it is more cost-effective and suitable for large-scale production of LCA.

A regulatory variant at 19p13.3 is associated with primary biliary cholangitis risk and ARID3A expression

Genome-wide association studies have identified 19p13.3 locus associated with primary biliary cholangitis (PBC). Here we aim to identify causative variant(s) and initiate efforts to define the mechanism by which the 19p13.3 locus variant(s) contributes to the pathogenesis of PBC. A genome-wide meta-analysis of 1931 PBC subjects and 7852 controls in two Han Chinese cohorts confirms the strong association between 19p13.3 locus and PBC. By integrating functional annotations, luciferase reporter assay and allele-specific chromatin immunoprecipitation, we prioritize rs2238574, an AT-Rich Interaction Domain 3A (ARID3A) intronic variant, as a potential causal variant at 19p13.3 locus. The risk allele of rs2238574 shows higher binding affinity of transcription factors, leading to an increased enhancer activity in myeloid cells. Genome-editing demonstrates the regulatory effect of rs2238574 on ARID3A expression through allele-specific enhancer activity. Furthermore, knock-down of ARID3A inhibits myeloid differentiation and activation pathway, and overexpression of the gene has the opposite effect. Finally, we find ARID3A expression and rs2238574 genotypes linked to disease severity in PBC. Our work provides several lines of evidence that a non-coding variant regulates ARID3A expression, presenting a mechanistic basis for association of 19p13.3 locus with the susceptibility to PBC.

The serum acylcarnitines profile in epileptic children treated with valproic acid and the protective roles of peroxisome proliferator-activated receptor a activation in valproic acid-induced liver injury

Valproic acid (VPA) is widely used as a major drug in the treatment of epilepsy. Despite the undisputed pharmacological importance and effectiveness of VPA, its potential hepatotoxicity is still a major concern. Being a simple fatty acid, the hepatotoxicity induced by VPA has long been considered to be due primarily to its interference with fatty acid β-oxidation (β-FAO). The aim of this study was to investigate the biomarkers for VPA-induced abnormal liver function in epileptic children and to determine potential mechanisms of its liver injury. Targeted metabolomics analysis of acylcarnitines (ACs) was performed in children's serum. Metabolomic analysis revealed that VPA -induced abnormal liver function resulted in the accumulation of serum long-chain acylcarnitines (LCACs), and the reduced expression of β-FAO relevant genes (Carnitine palmitoyltrans-ferase (CPT)1, CPT2 and Long-chain acyl-CoA dehydrogenase (LCAD)), indicating the disruption of β-FAO. As direct peroxisome proliferator-activated receptor a (PPARα)- regulated genes, CPT1A, CPT2 and LCAD were up-regulated after treatment with PPARα agonist, fenofibrate (Feno), indicating the improvement of β-FAO. Feno significantly ameliorated the accumulation of various lipids in the plasma of VPA-induced hepatotoxic mice by activating PPARα, significantly reduced the plasma ACs concentration, and attenuated VPA-induced hepatic steatosis. Enhanced oxidative stress and induced by VPA exposure were significantly recovered using Feno treatment. In conclusion, this study indicates VPA-induced β-FAO disruption might lead to liver injury, and a significant Feno protective effect against VPA -induced hepatotoxicity through reversing fatty acid metabolism.

Incomplete response to ursodeoxycholic acid in primary biliary cholangitis: criteria, epidemiology, and possible mechanisms

INTRODUCTION

As a common autoimmune disease with the characteristic of early complication, primary biliary cholangitis (PBC) leads to an increasing number of mortalities among people with end-stage liver disease (ESLD) waiting for liver transplantation. Ursodeoxycholic acid (UDCA) is the only approved first-line medicine for PBC, and a good response to treatment could acquire an ideal prognosis. Patients with poor UDCA response usually have more adverse outcomes and worse survival, therefore, the management of this group become a major consideration.

AREAS COVERED

Due to the complexity of race and environment for PBC, different criteria for UDCA response exhibit various predictive performances. Factors affecting UDCA response conditions include gender, age, ethnicity, serum indicators, auto-antibodies, and autoimmune comorbidities, while no agreement has been reached. In this review, we mainly focus on cellular senescence, immune-mediated damage, and vitamin D deficiency as possible mechanisms for UDCA non-responders.

EXPERT OPINION

The pathogenesis of PBC has yet to be clarified. Immunology-related mechanisms and therapy targets ought to be the main effort made for further study. Irrespective of the response condition, UDCA is recommended for routine administration in all PBC patients without contraindication. Ongoing clinical trials of second-line and additional therapy exhibit promising prospects.

Paeoniae Radix Rubra can enhance fatty acid β-oxidation and alleviate gut microbiota disorder in α-naphthyl isothiocyanate induced cholestatic model rats

Cholestasis is the most destructive pathological manifestation of liver disease and available treatments are very limited. Paeoniae Radix Rubra (PRR) is an important traditional Chinese drug used to treat cholestasis. This study combined targeted metabonomics, PCR array analysis, and 16S rRNA sequencing analysis to further clarify the mechanisms of PRR in the treatment of cholestasis. PRR conspicuously reversed the elevation of fatty acids (FFA 14:0 and other 14 fatty acids) and the decrease of organic acids (pyruvic acid and citric acid) in a cholestatic model induced by α-naphthyl isothiocyanate (ANIT). Eight elevated amino acids (L-proline, etc.) and five elevated secondary bile acids (taurohyodeoxycholic acid, etc.) in model rats were also reduced by PRR. Pathway analysis revealed that PRR significantly alleviated eight pathways (β-alanine metabolism). Furthermore, we found that PRR significantly reversed the decrease of Cpt1a, Hadha, Ppara, and Slc25a20 (four genes relevant to fatty acid β-oxidation) mRNAs caused by ANIT, and PRR conspicuously decreased nine acylcarnitines (the forms of fatty acids into mitochondria for β-oxidation) that increased in model rats. These results indicate that PRR could enhance fatty acid β-oxidation, which may be the way for PRR to reduce the levels of 15 fatty acids in the serum of model rats. 16S rRNA sequencing analysis revealed that PRR alleviated gut microbiota disorders in model rats, including upregulating four genera (Coprococcus, Lactobacillus, etc.) and downregulating four genera (Bacteroides, Escherichia, etc.). As the relative abundance of these eight genera was significantly correlated with the levels of the five secondary bile acids (deoxycholic acid, taurolithocholic acid, etc.) reduced by PRR, and Bacteroides and Escherichia were reported to promote the production of secondary bile acid, we inferred that the downregulation of PRR on five secondary bile acids in model rats was inseparable from gut microbiota. Thus, the gut microbiota also might be a potential pharmacological target for the anticholestatic activity of PRR. In conclusion, we consider that the mechanisms of PRR in treating cholestasis include enhancing fatty acid β-oxidation and alleviating gut microbiota disorders.

Targeted bile acid profiles reveal the liver injury amelioration of Da-Chai-Hu decoction against ANIT- and BDL-induced cholestasis

Multiple types of liver diseases, particularly cholestatic liver diseases (CSLDs) and biliary diseases, can disturb bile acid (BA) secretion; however, BA accumulation is currently seen as an important incentive of various types of liver diseases’ progression. Da-Chai-Hu decoction (DCHD) has long been used for treating cholestatic liver diseases; however, the exact mechanisms remain unclear. Currently, our study indicates that the liver damage and cholestasis status of the α-naphthylisothiocyanate (ANIT)-induced intrahepatic cholestasis and bile duct ligation (BDL)-induced extrahepatic cholestasis, following DCHD treatment, were improved; the changes of BA metabolism post-DCHD treatment were investigated by targeted metabolomics profiling by UPLC-MS/MS. DCHD treatment severely downregulated serum biochemical levels and relieved inflammation and the corresponding pathological changes including necrosis, inflammatory infiltration, ductular proliferation, and periductal fibrosis in liver tissue. The experimental results suggested that DCHD treatment altered the size, composition, and distribution of the BAs pool, led the BAs pool of the serum and liver to sharply shrink, especially TCA and TMCA, and enhanced BA secretion into the gallbladder and the excretion of BAs by the urinary and fecal pathway; the levels of BAs synthesized by the alternative pathway were increased in the liver, and the conjugation of BAs and the pathway of BA synthesis were actually affected. In conclusion, DCHD ameliorated ANIT- and BDL-induced cholestatic liver injury by reversing the disorder of BAs profile.

Human menstrual blood-derived stem cell transplantation suppresses liver injury in DDC-induced chronic cholestasis

Background

Cholestatic liver injury can lead to serious symptoms and prognoses in the clinic. Currently, an effective medical treatment is not available for cholestatic liver injury. Human menstrual blood-derived stem cells (MenSCs) are considered as an emerging treatment in various diseases. This study aimed to explore the treatment effect of MenSCs in cholestatic liver injury.

Methods

The treatment effect of MenSCs on chronic cholestatic liver injury was verified in 3,5-diethoxycarbonyl-1,4-dihydroxychollidine (DDC)-induced C57/BL6 mice. Pathological, fibrosis area in the liver tissue and serum liver enzymes were tested. Proteomics and western blot were used to explore the related targets and molecular mechanisms. Adeno-associated virus (AAV) 9-infected mice were applied for verification.

Results

MenSCs markedly improved the survival rate of the DDC-treated mice (60% vs. 100%), and decreased the mouse serum aspartate aminotransferase (AST) (169.4 vs. 108.0 U/L, p < 0.001), alanine aminotransferase (ALT) (279.0 vs. 228.9 U/L, p < 0.01), alkaline phosphatase (ALP) (45.6 vs. 10.6 U/L, p < 0.0001), direct bilirubin (DBIL) (108.3 vs. 14.0 μmol/L, p < 0.0001) and total bilirubin (TBIL) (179.2 vs. 43.3 μmol/L, p < 0.0001) levels as well as intrahepatic cholestasis, bile duct dilation and fibrotic areas (16.12 vs. 6.57%, p < 0.05). The results further indicated that MenSCs repaired the DDC-induced liver tight junction (TJ) pathway and bile transporter (OATP2, BSEP and NTCP1) injury, thereby inhibiting COL1A1, α-SMA and TGF-β1 activation by upregulating liver β-catenin expression.

Conclusions

MenSC transplantation could be an effective treatment method for cholestatic liver injury in mice. MenSCs may exhibit therapeutic effects by regulating β-catenin expression.

miRNA and miRNA target genes in intervention effect of Zhuyu pill on cholestatic rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Zhuyu pill (ZYP), an effective prescription of traditional Chinese medicine, is composed of Coptis chinensis Franch. and Tetradium ruticarpum (A. Jussieu) T. G. Hartley and has shown potential anticholestatic effects. However, its mechanism of action in treating cholestasis remains unclear. Since post-transcriptional control of mRNA by micro-RNAs (miRNAs) represents an important mechanism of gene regulation, it is promising to explore this in relation to ZYP and cholestasis.

AIM OF THE STUDY

To confirm the anticholestatic effect of ZYP and to explore its potential biological mechanism.

MATERIALS AND METHODS

In this study, a cholestasis rat model was induced by α-naphthyl-isothiocyanate (ANIT, 50 mg/kg) and treated with ZYP (low dose: 0.6 g/kg, high dose: 1.2 g/kg). Serum biochemistry indices and liver histopathology were used to evaluate the model and efficacy, and miRNA sequencing was used to measure differences in miRNA expression in the liver between the control, model, low-dose ZYP, and high-dose ZYP groups. To verify the accuracy of sequencing results and explore the potential anti-cholestasis mechanism of ZYP, RT-PCR was used to identify differentially expressed miRNAs and their target genes.

RESULTS

Both high- and low-dose ZYP exhibited significant anticholestatic effects, with the high-dose showing better effects than low-dose ZYP. Additionally, four differentially expressed miRNAs, rno-miR-147, rno-miR-20b-5p, rno-miR-29b-3p, and rno-miR-3586-3p, were found to be upregulated in cholestasis and downregulated after ZYP intervention. Eight target genes of the above miRNAs, including ABCG8, CLOCK, PLEC, SLC4A2, NEB, ADAMTS12, TTN and FAM174B were inhibited in cholestatic rats, exhibiting up-regulated expression tendencies after ZYP intervention, and the expression tendencies were significant negatively correlated with serum biochemical indices.

CONCLUSIONS

ZYP can significantly reduce liver biochemical indices and improve liver tissue damage in cholestasis rats through the regulation of miRNA expression in the liver, producing a positive regulatory effect on bile excretion-related genes.

Bile acid-induced tissue factor activity in hepatocytes correlates with activation of farnesoid X receptor

Bile acids (BA) have been found to promote coagulation by increasing tissue factor (TF) activity. The contribution of elevated BA levels and cholestasis to TF decryption within the liver parenchyma and the role of farnesoid X receptor (FXR) in this process remain unclear. We investigated the effects of BA on TF activity and thrombin generation in hepatocytes and correlated these effects with activation of FXR-dependent signaling and apoptosis. HepG2 cells and primary hepatocytes were incubated with chenodeoxycholic acid (CDCA), glycochenodeoxycholic acid (GCDCA), ursodeoxycholic acid (UCDA), or the synthetic FXR agonist GW4064 for 24 h. MTT tests demonstrated cell viability throughout experiments. TF activity was tested via factor Xa generation and thrombin generation was measured by calibrated automated thrombography. Increased TF activity alongside enhanced thrombin generation was observed with CDCA and GW4064 but not with GCDCA and UDCA. TF activity was substantially reduced when FXR activation was blocked with the antagonist DY 268. Quantitative polymerase chain reaction revealed upregulation of FXR target genes only by CDCA and GW4064. Western blot analysis and fluorescence microscopy showed no TF overexpression arguing for TF decryption. Caspase 3 activity measurements and flow cytometric analysis of Annexin V binding showed no signs of apoptosis. Long-term exposure of hepatocytes to nontoxic BA may cause intracellular FXR overstimulation, triggering TF decryption irrespective of the amphiphilic properties of BA. The effect of BA on TF activation correlates with the molecule's ability to enter the cells and activate FXR. TF decryption occurs independently of apoptotic mechanisms.

Allopurinol Protects Against Cholestatic Liver Injury in Mice Not Through Depletion of Uric Acid

Cholestasis is one of the most severe manifestations of liver injury and has limited therapeutic options. Allopurinol (AP), an inhibitor of uric acid (UA) synthesis, was reported to prevent liver damage in several liver diseases. However, whether AP protects against intrahepatic cholestatic liver injury and what is the role of UA in the pathogenesis of cholestasis remain unknown. In this study, we reported that AP attenuated liver injury in a mouse model of intrahepatic cholestasis induced by alpha-naphthylisothiocyanate (ANIT). AP showed no significant effect on glutathione depletion, inflammation, or bile acid metabolism in livers of ANIT-treated mice. Instead, AP significantly improved fatty acid β-oxidation in livers of ANIT-treated mice, which was associated with activation of PPARα. The protective effect of AP on cholestatic liver injury was not attributable to the depletion of UA, because both exogenous and endogenous UA prevented liver injury in ANIT-treated mice via inhibition of NF-kB-mediated inflammation. In conclusion, the present study provides a new perspective for the therapeutic use of AP and the role of UA in cholestatic liver injury.

Decreased infiltration of CD4+ Th1 cells indicates a good response to ursodeoxycholic acid (UDCA) in primary biliary cholangitis

BACKGROUND

Primary biliary cholangitis (PBC) is characterized by nonsuppurative destructive cholangitis and is thought to be an autoimmune disorder. Currently, ursodeoxycholic acid (UDCA) is the only FDA approved first-line therapy for PBC, but up to nearly one-third of patients do not achieve a complete response to this treatment. Adaptive immune cells, including T cells and B cells, have been found in the portal tracts and the bile duct epithelium and play a role in the pathogenesis of PBC, but the importance of these cells for evaluating the therapeutic response to UDCA in PBC has not yet been studied.

METHODS

In this study, we collected liver puncture biopsy specimens from 34 matched patients with PBC before and after UDCA treatment and investigated the relationship between the infiltration of adaptive immune cells and the treatment response to UDCA. The extent of immune cell infiltration was determined by immunohistochemical analysis. Responses were defined based on Paris-I criteria.

RESULTS

After 1 year of treatment, 25/34 patients responded to UDCA treatment according to Paris-I criteria (responders), and 9/34 patients were nonresponders. Immunohistochemical analysis showed that UDCA responders exhibited significantly less CD4⁺ T cell infiltration after UDCA treatment than before (50.4 ± 7.5/HPF vs 30.0 ± 7.9/HPF, P = 0.002). In contrast, UDCA nonresponders exhibited significantly more CD4⁺ T cell infiltration after UDCA treatment than before (32.2 ± 8.0/HPF vs 75.0 ± 13.9/HPF, P = 0.045). Moreover, patients who exhibited a reduction in CD4⁺ T cell infiltration after UDCA treatment had a higher response rate than those that exhibited an increase in CD4⁺ T cell infiltration (85.7 % vs 53.8 %, P = 0.041). However, CD3⁺ T cell, CD8⁺ T cell, and CD20⁺ B cell infiltration was not significantly different before and after treatment in either UDCA responders or nonresponders. Furthermore, we found that the number of infiltrating T-bet⁺ Th1 cells was much lower after UDCA treatment than before in responders (10.5 ± 5.7/HPF vs. 5.16 ± 4.0/HPF, P = 0.0214) but much higher in nonresponders after treatment than before (1.89±1.2/HPF vs. 12.3±5.4/HPF, P = 0.043). However, there was no difference in the extent of GATA3⁺ Th2 or FOXP3⁺ Treg infiltration before and after treatment in either UDCA responders or nonresponders.

CONCLUSION

Collectively, our results suggest that a decrease in the number of liver-infiltrating CD4⁺ Th1 cells is associated with a good response of PBC patients to UDCA treatment. Immunohistochemical analysis of CD4 and T-bet in PBC liver specimens may be a potential approach for evaluating the therapeutic response to UDCA.

Animal Models of Autoimmune Liver Diseases: a Comprehensive Review

Autoimmune liver diseases (AILDs) are potentially life-threatening chronic liver diseases which include autoimmune hepatitis, primary biliary cholangitis, primary sclerosing cholangitis, and recently characterized IgG4-related sclerosing cholangitis. They are caused by immune attack on hepatocytes or bile ducts, with different mechanisms and clinical manifestations. The etiologies of AILDs include a susceptible genetic background, environment insults, infections, and changes of commensal microbiota, but remain complicated. Understanding of the underlying mechanisms of AILDs is mandatory for early diagnosis and intervention, which is of great importance for better prognosis. Thus, animal models are developed to mimic the pathogenesis, find biomarkers for early diagnosis, and for therapeutic attempts of AILDs. However, no animal models can fully recapitulate features of certain AILD, especially the late stages of diseases. Certain limitations include different living condition, cell composition, and time frame of disease development and resolution. Moreover, there is no IgG4 in rodents which exists in human. Nevertheless, the understanding and therapy of AILDs have been greatly advanced by the development and mechanistic investigation of animal models. This review will provide a comprehensive overview of traditional and new animal models that recapitulate different features and etiologies of distinct AILDs.

Comprehensive Analysis of Serum and Fecal Bile Acid Profiles and Interaction with Gut Microbiota in Primary Biliary Cholangitis

Accumulation of bile acids (BAs) contributes significantly to the pathogenesis of primary biliary cholangitis (PBC). Here, we sought to systematically characterize the serum and fecal BA profiles and the linkage between BAs and gut microbiota in PBC. The serum and fecal BAs were compared between 65 UDCA treatment-naive PBC and 109 healthy controls using UPLC-MS in cross-sectional study. In a prospective study, a subgroup of patients was enrolled for BA and microbiota analysis before and after UDCA therapy. BA compositions in serum and feces significantly differed between treatment-naive PBC and controls. Particularly, PBC was associated with decreased conversions of conjugated to unconjugated, and primary to secondary BAs, indicating impaired microbial metabolism of BAs. PBC patients at advanced stage exhibited a more abnormal BA profile compared with early-stage patients. UDCA treatment led to a decreased level of taurine-conjugated BAs, thereby reversing the conjugated/unconjugated ratio in PBC. Moreover, the level of secondary BAs such as DCA and conjugated DCA inversely correlated with PBC-enriched gut microbes (e.g., Veillonella, Klebsiella), while positively correlated with control-enriched microbes (e.g., Faecalibacterium, Oscillospira). Microbiota analysis also revealed a significant increase of taurine-metabolizing bacteria Bilophila spp. in patients after UDCA, which was strongly correlated with decreased taurine-conjugated BAs. In addition, serum FGF19 was remarkably increased in treatment-naïve PBC and decreased after UDCA. Our study established specific alterations of BA compositions in serum and feces of PBC, suggesting the potential for using BAs for diagnosis, and highlighting the possibility of modulating BA profile by altering gut microbiota. Graphical Abstract.

Metabolomics research on the hepatoprotective effect of cultured bear bile powder in α-naphthylisothiocyanate-induced cholestatic mice

Natural bear bile powder (NBBP) is a famous traditional medicine and has been widely used in clinic. However, access to the sources of bear bile is restricted; hence, it is essential to discover new substitutes for NBBP. Cultured bear bile powder (CBBP) is transformed from chicken bile and contains main ingredients as to NBBP. In the present study, the effect and potential mechanism of action of CBBP on cholestatic liver injury in-naphthylisothiocyanate (ANIT)-induced mouse model was explored using metabolomics. CBBP treatment ameliorated impaired hepatic dysfunction and tissue damage that induced by ANIT. Metabolomics showed there were 28 different metabolites induced by ANIT as compared with control mice, and 18 of which was reversed by CBBP. Pathway analysis revealed that those 18 metabolites are mainly involved in bile acid (BA) biosynthesis and D-glutamine and D-glutamate metabolism. Further LC-MS/MS analysis showed that CBBP and NBBP both reduced serum and liver levels of BAs, but increased their biliary levels. Additionally, CBBP and NBBP upregulated expression of BA efflux transporters, Mrp2, Mrp3, and Mrp4, and metabolic enzymes, Cyp2b10 and Ugt1a1 of liver tissue of cholestatic mice, increased the BA excretion and metabolism. Moreover, CBBP and NBBP treatment upregulated GCLc/GCLm expression, and restored glutathione metabolism. In conclusion, the protective effects of CBBP against cholestatic liver injury were similar to those of NBBP. Mechanistically, both CBBP and NBBP reversed the disruption in homeostasis of BAs and glutathione, alleviating damage to hepatocytes.

Synthesis of ursodeoxycholic acid from plant-source (20S)-21-hydroxy-20-methylpregn-4-en-3-one

A novel synthetic route of producing ursodeoxycholic acid (UDCA) was developed through multiple reactions from cheap and commercially available bisnoralcohol (BA). The key reaction conditions, including solvents, bases and reaction temperatures of the route were investigated and optimized. In the straightforward route for preparation of UDCA, most of the reaction steps have high conversions with average yields of 91%, and overall yield up to 59% (6 steps) from the plant-source BA. Especially in the last step of reduction and hydrolysis, there are five functional groups converted with calcd 97% per conversion in one-pot reaction. This promising route offers economical and efficient strategies for potential large-scale production of UDCA.

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.

Possible application of melatonin treatment in human diseases of the biliary tract

Melatonin was discovered in 1958 by Aaron Lerner. Its name comes from the ability of melatonin to change the shape of amphibian melanophores from stellate to roundish. Starting from the 1980s, the role of melatonin in the regulation of mammalian circadian and seasonal clocks has been elucidated. Presently, several other effects have been identified in different organs. For example, the beneficial effects of melatonin in models of liver damage have been described. This review gives first a general background on experimental and clinical data on the use of melatonin in liver damage. The second part of the review focuses on the findings related to the role of melatonin in biliary functions, suggesting a possible use of melatonin therapy in human diseases of the biliary tree.

Evaluation of the United Kingdom-primary biliary cholangitis and global primary biliary cholangitis group prognostic models for primary biliary cholangitis patients treated with ursodeoxycholic acid in the U.S. population

Background and Aim

The United Kingdom‐primary biliary cholangitis (UK‐PBC) and global primary biliary cholangitis group (GLOBE) prognostic models have been recently developed to predict long‐term outcomes in primary biliary cholangitis (PBC). However, these predictive scores have not yet been well evaluated in the U.S. population.

Methods

We retrospectively reviewed newly diagnosed PBC patients at the Cleveland Clinic between November 1998 and February 2017. Adverse events were defined as liver transplantation, liver‐related mortality, and all‐cause mortality. Transplant‐free survival (TFS) was estimated using the Kaplan–Meier method. Predictive performances of all prognostic models were evaluated using the C‐statistic.

Results

We identified 352 patients who used ursodeoxycholic acid therapy. Of them, 311 (88.4%) only had PBC, while 41 (11.6%) were diagnosed with PBC‐autoimmune hepatitis overlap. A total of 22 (6%), 47 (13%), and 55 (16%) patients had adverse events within 5, 10, and 15 years after diagnosis, respectively. In patients with PBC only, the C‐statistic in predicting 15‐year adverse events was 0.75 per GLOBE compared to 0.74 per UK‐PBC (P = 0.94), 0.73 per Rotterdam (P = 0.44), 0.66 per Barcelona (P = 0.004), 0.65 per Paris 1 (P = 0.005), 0.62 per Paris 2 (P < 0.0001), 0.60 per Toronto (P < 0.0001), and 0.60 per Mayo (P < 0.0001) scores. Median follow‐up was 9.2 years. Ten‐year TFS for patients who had optimal versus suboptimal treatment response was 92 versus 74% per Paris 1 (P < 0.0001), 95 versus 79% per Paris 2 (P = 0.0002), 93 versus 65% per Barcelona (P < 0.0001), and 96 versus 68% per Rotterdam (P < 0.0001) risk scores, respectively.

Conclusion

In our cohort of PBC patients, the UK‐PBC and GLOBE scores were both accurate and reasonably valid prognostic models in the U.S. population.

Epidemiology of primary biliary cholangitis in Italy: Evidence from a real-world database

BACKGROUND

Primary biliary cholangitis is an autoimmune disease affecting the interlobular bile ducts. Limited information is available on its epidemiology and treatment in Italy.

AIMS

To describe primary biliary cholangitis epidemiology and investigate treatment patterns for Italian patients with this disease.

METHODS

Electronic medical records from 900 general practitioners (part of the QuintilesIMS™ Longitudinal Patient Databases) were examined. Demographics were compared with those from the Italian National Institute of Statistics dataset. The International Classification of Diseases, Ninth Revision, biliary cirrhosis code 571.6 was used for diagnosis, and data on comorbidities, concomitant medications, medical examinations, specialist referrals, and treatments were collected.

RESULTS

This dataset was representative of the Italian population. Point prevalence of primary biliary cholangitis was calculated as 27.90 per 100,000 and incidence as 5.31 per 100,000 inhabitants/year. Some associations between the disease and comorbidities were sex specific. The most common laboratory assays requested were for liver enzymes, and the majority of patients were not referred to a specialist. Ursodeoxycholic acid was the most common therapy.

CONCLUSION

This can be used as a benchmark for monitoring and identifying unmet needs to improve treatment in Italy.

Obeticholic acid in primary biliary cholangitis: where we stand

PURPOSE OF REVIEW

This review will summarize the use of obeticholic acid (OCA) in treatment of primary biliary cholangitis (PBC). It seeks to discuss the mechanism of action, evidence for use, appropriate clinical use, and common adverse effects of OCA.

RECENT FINDINGS

PBC is a chronic, progressive cholestatic liver disease that is a chronic progressive that may lead to end-stage liver disease and need for liver transplantation. Ursodeoxycholic acid (UDCA) has been the mainstay of therapy for PBC for decades. Recent research has led to the discovery that bile acids act as hormones and have many effects, one of which is activating the farnesoid X receptor (FXR). Activation of FXR leads to decreased bile acid synthesis, inflammation, and fibrosis of the liver. OCA is a highly potent FXR agonist.

SUMMARY

Several clinical trials demonstrated that OCA treatment in PBC led to a significant decrease in serum alkaline phosphatase, a marker for long-term survival. The US FDA-approved OCA in 2016, which led to incorporation of OCA into current guidelines as a second-line treatment for PBC. The most clinically relevant adverse effect of OCA is dose-related pruritus. We review the role of OCA and current guidelines in treatment of PBC.

Proteomics in Primary Biliary Cholangitis

Primary biliary cholangitis is a chronic cholestatic liver disease characterized by the presence of serum antimitochondrial antibodies and immune-mediated destruction of the small and medium-sized intrahepatic bile ducts. However, the pathophysiology of primary biliary cholangitis has not yet been completely elucidated. In recent years, proteomics has been comprehensively applied in many research fields, including the pathogenesis, prognosis, and diagnosis of disease. Among multiple methods, isobaric tag for relative and absolute quantitation is a powerful analytic method to characterize complex protein mixtures in combination with liquid chromatography-tandem mass spectrometry. In this chapter, we describe a strategy for using isobaric tag for relative and absolute quantitation to discover those differentially expressed proteins in primary biliary cholangitis. The goal is to identify the differences in protein expression between patients with primary biliary cholangitis and healthy controls for defining biomarkers and elucidating molecular mechanisms underlying disease states.

Celastrol Protects From Cholestatic Liver Injury Through Modulation of SIRT1-FXR Signaling

Celastrol, derived from the roots of the Tripterygium Wilfordi, shows a striking effect on obesity. In the present study, the role of celastrol in cholestasis was investigated using metabolomics and transcriptomics. Celastrol treatment significantly alleviated cholestatic liver injury in mice induced by α-naphthyl isothiocyanate (ANIT) and thioacetamide (TAA). Celastrol was found to activate sirtuin 1 (SIRT1), increase farnesoid X receptor (FXR) signaling and inhibit nuclear factor-kappa B and P53 signaling. The protective role of celastrol in cholestatic liver injury was diminished in mice on co-administration of SIRT1 inhibitors. Further, the effects of celastrol on cholestatic liver injury were dramatically decreased in Fxr-null mice, suggesting that the SIRT1-FXR signaling pathway mediates the protective effects of celastrol. These observations demonstrated a novel role for celastrol in protecting against cholestatic liver injury through modulation of the SIRT1 and FXR.

A facile synthesis of ursodeoxycholic acid and obeticholic acid from cholic acid

A novel synthetic route of producing ursodeoxycholic acid (UDCA) and obeticholic acid (OCA) was developed through multiple reactions from cheap and readily-available cholic acid. The reaction conditions of the key elimination reaction of mesylate ester group were also investigated and optimized, including solvent, base and reaction temperature. In the straightforward synthetic route for preparation of UDCA and OCA, most of the reaction steps have high conversions with average yields of 94% and 92%, and overall yield up to 65% (7 steps) and 36% (11 steps) from cholic acid, respectively. This promising route offers economical and efficient strategies for potential large-scale production of UDCA and OCA.

Characteristics and Outcomes of Liver Transplantation for Primary Biliary Cholangitis in Young Patients: Analysis of the United Network for Organ Sharing Database

BACKGROUND

Primary biliary cholangitis (PBC) in younger patients has been suggested to require liver transplantation (LT) in early adulthood, but data is limited on its outcomes. We aimed to evaluate the characteristics and outcome of LT in young patients with PBC in comparison with older adults.

METHODS

The United Network for Organ Sharing database was analyzed for all patients with PBC who underwent LT between 2000 and 2012. Based on age at the time of LT, subjects were divided into 2 groups: young patients (≤40 y) and older adults (≥41 y). Baseline demographics, clinical parameters, and outcomes of LT were then compared between the 2 groups. Univariable and multivariable analyses were performed to assess the factors associated with outcomes of LT.

RESULTS

A total of 2084 patients with PBC were included in the analysis with 158 young patients. Compared with older adults, younger patients were more likely to be male (27.2% versus 15.4%) and nonwhite (43.7% versus 21.5%), but they were less likely to have obesity, diabetes, or hypertension (P < 0.05) and had a lower mortality (8.2% versus 15.1%) but higher retransplantation rate (14.6% versus 4.7%) (P < 0.001). On multivariable analysis, older age, dialysis or ventilator use, and lower albumin were associated with high post-LT mortality.

CONCLUSIONS

Compared with older adults, early-onset PBC in younger patients requiring LT had higher percentage of males and nonwhites and had a lower prevalence of metabolic comorbidities but higher retransplantation rates. Further studies are warranted to confirm these findings.

Mesenchymal stem cells alleviate experimental autoimmune cholangitis through immunosuppression and cytoprotective function mediated by galectin-9

Background

Mesenchymal stem cells (MSCs) play an anti-inflammatory role by secreting certain bioactive molecules to exert their therapeutic effects for disease treatment. However, the underlying mechanism of MSCs in chronic autoimmune liver diseases—primary biliary cholangitis (PBC), for example—remains to be elucidated.

Methods

Human umbilical cord–derived MSCs (UC-MSCs) were injected intravenously into 2-octynoic acid coupled to bovine serum albumin (2OA-BSA)-induced autoimmune cholangitis mice. Serum levels of biomarkers and autoantibodies, histologic changes in the liver, diverse CD4⁺ T-cell subsets in different tissues, and chemokine activities were analyzed. Moreover, we investigated galectin-9 (Gal-9) expression and its function in UC-MSCs.

Results

In this study, UC-MSC transplantation (UC-MSCT) significantly ameliorated liver inflammation, primarily by diminishing T helper 1 (Th1) and Th17 responses as well as modifying liver chemokine activities in experimental autoimmune cholangitis mice. Mechanistically, UC-MSCs significantly repressed the proliferation of CD4⁺ T cells and suppressed the differentiation of Th1 and Th17 cells, which was likely dependent on Gal-9. Furthermore, the signal transducer and activator of transcription (STAT) and c-Jun N-terminal kinase (JNK) signaling pathways were involved in the production of Gal-9 in UC-MSCs.

Conclusions

These results suggest that Gal-9 contributes significantly to UC-MSC–mediated therapeutic effects and improve our understanding of the immunomodulatory mechanisms of MSCs in the treatment of PBC.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0979-x) contains supplementary material, which is available to authorized users.

9-cis-retinoic acid elevates MRP3 expression by inhibiting sumoylation of RXRα to alleviate cholestatic liver injury

AIMS

Vitamin A and its metabolites has been found to be protective against cholestatic liver injury, but the exact underlying mechanisms involved in cholestatic liver injury remain unclear. The objective of this study was to determine the function and mechanisms of 9-cis-retinoic acid, the metabolite of vitamin A, in cholestatic liver injury.

METHODS

The bile duct ligated (BDL) mice were treated with 9-cis-retinoic acid by intravenous injection through the tail for 10 days. The liver function and histology were assessed in the matched group and experimental group. The expression of MRP3 in liver tissue was tested by qRT-PCR, Western blotting, and IHC. Effect of RXRα sumoylation on MRP3 expression was investigated at a cellular level. Influence of 9-cis-retinoic acid on RXRα sumoylation was also tested in cells.

RESULTS

Our findings showed that 9-cis-retinoic acid significantly decreases the serum ALT and AST level, alleviates hepatic necrosis of the BDL-mice. We also identified MRP3, an important protective hepatobiliary transporter in cholestasis, was elevated by 9-cis-retinoic acid in vivo and in vitro. 9-cis-retinoic acid weakened the sumoylation of RXRα, which promotes the cytoplasmic location of RXRα and lightens the interaction of RXRα and RARα. Inhibition of RXRα and RARα interaction increased MRP3 expression.

CONCLUSIONS

9-cis-retinoic acid alleviates cholestatic liver injury by elevating MRP3 expression through its mechanism of inhibiting sumoylation of RXRα.

Autoantibodies in Autoimmune Hepatitis: Can Epitopes Tell Us about the Etiology of the Disease?

Autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) are serious autoimmune liver diseases that are characterized by a progressive destruction of the liver parenchyma and/or the hepatic bile ducts and the development of chronic fibrosis. Left untreated autoimmune liver diseases are often life-threatening, and patients require a liver transplantation to survive. Thus, an early and reliable diagnosis is paramount for the initiation of a proper therapy with immunosuppressive and/or anticholelithic drugs. Besides the analysis of liver biopsies and serum markers indicating liver damage, the screening for specific autoantibodies is an indispensable tool for the diagnosis of autoimmune liver diseases. Such liver autoantigen-specific antibodies might be involved in the disease pathogenesis, and their epitope specificity may give some insight into the etiology of the disease. Here, we will mainly focus on the generation and specificity of autoantibodies in AIH patients. In addition, we will review data from animal models that aim toward a better understanding of the origins and pathogenicity of such autoantibodies.

PPARα activation protects against cholestatic liver injury

Intrahepatic cholestasis induced by drug toxicity, bile salt export pump (BSEP) deficiency, or pregnancy frequently causes cholestatic liver damage, which ultimately may lead to liver fibrosis and cirrhosis. Here, the preventive and therapeutic effects of peroxisome proliferator-activated receptor α (PPARα) signaling activated by fenofibrate was evaluated on cholestatic liver damage. Metabolomic analysis revealed that alpha-naphthyl isothiocyanate (ANIT)-induced intrahepatic cholestasis resulted in the accumulation of serum long-chain acylcarnitines and triglyceride, and the reduced expression of four fatty acid β-oxidation (β-FAO) relevant genes (Cpt1b, Cpt2, Mcad and Hadha), indicating the disruption of β-FAO. The increase of acylcarnitines in hepatic cell resulted in the enhanced expression of anti-oxidative genes glutathione S-transferases (Gsta2 and Gstm3) directly. As direct PPARα-regulated genes, Cpt1b, Cpt2, and Mcad were up-regulated after pretreatment with PPARα agonist, fenofibrate, indicating the improvement of β-FAO. In the end, the disrupted bile acid metabolism in the enterohepatic circulation and the enhanced oxidative stress and inflammation cytokines induced by ANIT exposure were significantly recovered with the improvement of β-FAO using fenofibrate treatment. These findings provide the rationale for the use of PPARα agonists as therapeutic alternatives for cholestatic liver damage.

Bile acids and intestinal microbiota in autoimmune cholestatic liver diseases

Autoimmune cholestatic liver diseases, including primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), are manifested as an impairment of normal bile flow and excessive accumulation of potentially toxic bile acids. Endogenous bile acids are involved in the pathogenesis and progression of cholestasis. Consequently, chronic cholestasis affects the expression of bile acid transporters and nuclear receptors, and results in liver injury. Several lines of evidence suggest that intestinal microbiota plays an important role in the etiopathogenesis of cholestatic liver diseases by regulating metabolism and immune responses. However, progression of the disease may also affect the composition of gut microbiota, which in turn exacerbates the progression of cholestasis. In addition, the interaction between intestinal microbiota and bile acids is not unidirectional. Bile acids can shape the gut microbiota community, and in turn, intestinal microbes are able to alter bile acid pool. In general, gut microbiota actively communicates with bile acids, and together play an important role in the pathogenesis of PBC and PSC. Targeting the link between bile acids and intestinal microbiota offers exciting new perspectives for the treatment of those cholestatic liver diseases. This review highlights current understanding of the interactions between bile acids and intestinal microbiota and their roles in autoimmune cholestatic liver diseases. Further, we postulate a bile acids-intestinal microbiota-cholestasis triangle in the pathogenesis of autoimmune cholestatic liver diseases and potential therapeutic strategies by targeting this triangle.

Treatment of PBC-A step forward

Recent years have seen a growing interest in PBC within the scientific community, healthcare providers and industries, coupled with great advances in the understanding of the molecular and genetic basis and the natural history of the disease. Several disease-modifying agents targeting the immune-mediated response and bile-acid therapies are at different stages of development, some with promising results. A new drug, obeticholic acid, has been recently registered in the US and Europe as a second-line treatment in refractory PBC. International cohort studies have highlighted a disease heterogeneity, and so the need to provide patients with a more personalised management based on their risk of disease progression. Major challenges remain the development of surrogate endpoints in clinical trials acceptable to regulatory authorities, in a disease with a relatively low rate of events; and the development of clinical tools for patient's risk stratification and selection of those with greatest potential benefit from second-line therapies.

Finding the cure for primary biliary cholangitis - Still waiting

The introduction of ursodeoxycholic acid (UDCA)may well have contributed to some of the improvements in morbidity and mortality of primary biliary cholangitis (PBC). Yet nearly 40% of PBC patients are unresponsive to UDCA. Further the data on UDCA is confounded by the changes in the goepidemiology and particularly the earlier diagnosis of PBC. In this regard we welcome the addition of obeticholic acid (OCA) as an alternative therapeutic option forthe treatment of PBC in those patients refractory to UDCA. However, OCA is intellectually disappointing.There is no data on OCA that reflects dynamic and critical endpoints, for example death or liver transplantation; only surrogate endpoints have been used in the clinical trials. A nested study with liver histology wouldbeanideal surrogate marker,including intensive use of immunohistochemistry to define cellular infiltrates and cytokine/chemokine activity. More importantly, the clinical characteristics of PBCmay vary among patients and progression is not always predictable. We need to identify more appropriate and specific biomarkers that predict the clinical course, and we need to know which therapies are applicable at different stages, since treatmentfor PBC should be individualized. We need to know more about the etiology of PBC,and we want a cure for PBC.