Primary sclerosing cholangitis - a comprehensive review

Advanced liver-on-chip model mimicking hepatic lobule with continuous microvascular network via high-definition laser patterning

There is a great demand for development of advanced in vitro liver models to predict the efficacy and safety of drug candidates accurately in the preclinical drug development. Despite the great efforts to develop biomimetic models, it remains challenging to precisely mimic a functional unit of the liver (i.e., hepatic lobule) with a continuous microvascular network. Recent progress in laser patterning has allowed us to create arbitrary biomimetic structures with high resolution. Here, we propose an advanced liver-on-chip model mimicking the hepatic lobule with a continuous microvascular network, ranging from the microvessels to the central vein of the liver, utilizing femtosecond laser patterning. Firstly, we optimize the laser power to pattern microchannels mimicking the microvessel and central vein of the hepatic lobule by using a femtosecond laser within a collagen-based hydrogel containing hepatic cells. Secondly, we construct continuous microvessels with luminal structures by comparing different microchannel sizes in diameter. Finally, we assemble a millimeter-scale hepatic lobule-like structure with multiple layers of microvascular networks in the liver-on-chip. Furthermore, our liver-on-chip model exhibits major liver functions and drug-induced hepatotoxicity, as evidenced by albumin and urea productions and by a toxic response to acetaminophen, respectively. Our approach provides valuable strategies for the development of advanced physiological and pathological liver-on-chip models for pharmaceutical and toxicological studies.

Surveillance of primary sclerosing cholangitis - a comparison of scheduled or on-demand ERCP with annual MRI surveillance: a multicenter study

Primary sclerosing cholangitis (PSC) is associated with a high risk of hepatobiliary malignancy, especially cholangiocarcinoma (CCA). There are no good tumor markers to screen for CCA, and current recommendations for PSC monitoring are mainly based on expert opinions. The optimal strategy to assess disease progression and screen for CCA - the main cause of death of PSC patients - remains unclear. We aimed to compare three different surveillance strategies and their effect on patient outcomes.Data from three distinct PSC cohorts with different surveillance strategies - scheduled endoscopic retrograde cholangiopancreatography (ERCP), annual magnetic resonance imaging/cholangiopancreatography (MRI/MRCP) surveillance, and on-demand ERCP according to ESGE/EASL guidelines - was collected. Patients with PSC diagnosed in 1990 or later were included and the last day of follow-up was 31 December 2023. The composite end point consisted of hepatobiliary malignancy, liver transplantation, or liver-related death.1629 PSC patients were included, with a median follow-up of 8-11 years. The cumulative incidence of the composite end point was lowest in the group undergoing scheduled ERCP (14.1%, 95%CI 12.0%-16.4%) and highest in the on-demand ERCP cohort (35.0%, 95%CI 28.4%-42.0%). Although the cumulative incidence of CCA was lower in the scheduled ERCP group than in the other groups, it did not differ statistically significantly from the MRI/MRCP surveillance group. No differences were seen in liver-related deaths between the surveillance strategies.In this study comparing scheduled ERCP, annual MRI/MRCP surveillance, and on-demand ERCP, the strategy based on scheduled ERCP using individual risk stratification is associated with better overall prognosis and outcome.

β-Sitosterol protects against lithocholic acid-induced hepatotoxicity and cholestasis via farnesoid X receptor-mediated regulation of transporters and enzymes in vitro and in vivo

Cholestasis arises as a clinical syndrome triggered by the accumulation and aggregation of bile acids. Currently, there are only a few treatment options available for cholestasis. Therefore, it is necessary to explore novel therapeutic strategies. β-sitosterol (SIT), the phytosterol most abundantly found in plants, exhibits diverse pharmacological activities. This study examined SIT's protective role against hepatotoxicity and cholestasis induced by lithocholic acid (LCA). LCA was administered twice a day to male C57BL/6 mice for four days to cause hepatotoxicity and cholestasis. Assessment of the improvement in cholestasis following SIT treatment used H&E staining and serum biomarkers. Mice hepatocyte culture, real-time PCR, immunofluorescence staining, and Western blot were utilized to clarify the mechanisms of SIT hepatoprotection. Furthermore, molecular docking and dual-luciferase reporter gene analysis were utilized to show that SIT would activate the farnesoid X receptor (FXR). In vivo, SIT reduced bile acid accumulation by inducing the bile salt export pump (Bsep), multidrug resistance-related protein 2 (Mrp2), and reduced hepatic uptake of bile acids by inhibiting Na+/taurocholate co-transporting polypeptide (Ntcp), and cholesterol 7α-hydroxylase (Cyp7a1) and oxysterol 12α-hydroxylase (Cyp8b1) while in vitro, it restored FXR expression and transcriptional activity. Besides, SIT decreased hepatic inflammation by suppressing the inflammatory genes NF-κB p65 and p-NF-κB p65, TNF-α, IL-6, and IL-1β. However, the hepatoprotective effects of SIT were abolished by the FXR antagonist guggulsterone in vivo and FXR siRNA in vitro, confirming FXR-dependent mechanisms. In conclusion, SIT protects against LCA-induced hepatotoxicity and cholestasis via FXR activation. These findings highlight SIT as a promising therapeutic candidate for cholestasis.

Patient Reported Outcomes in Primary Sclerosing Cholangitis: An Australian Perspective

BACKGROUND AND AIMS

Primary sclerosing cholangitis (PSC) is a rare, cholestatic liver condition that has a significant association with inflammatory bowel disease (IBD) and impaired health-related quality of life (HRQOL). We aimed to characterise and compare validated PSC and IBD patient-reported outcomes (PRO) and determine if PRO correlated with the severity of liver disease.

METHODS

We conducted a multicentre, prospective cohort study in Australia enrolling adult patients with PSC from December 2019 to August 2023. Consecutive patients completed a baseline validated PSC PRO questionnaire and a short IBD questionnaire (SIBDQ) if they had concomitant IBD. Linear regression was used to explore factors associated with poor HRQOL and the association between each HRQOL domain and the severity of liver disease.

RESULTS

A total of 55 PSC patients were included. Most patients were male (32/55, 58%) with a median age of 44 years and a median 7 years of follow-up from PSC diagnosis. Mental and physical fatigue were the most prominent PSC symptoms. All HRQOL domain scores except PSC symptoms were significantly associated with liver disease severity. Decompensated cirrhosis and a history of cholangitis were associated with reduced HRQOL in various domains, whereas older age was protective against emotional distress (p = 0.01). IBD bowel symptoms and emotional impact had a positive correlation with PSC symptoms and emotional impact within the same patient.

CONCLUSION

This is the first Australian study describing PSC and IBD PRO in a well-characterised prospective cohort. We have demonstrated that PSC-related PRO is significantly associated with liver disease severity. Further large-scale studies are required to further interrogate these findings.

Diet-microbiome interactions in cancer

Diet impacts cancer in diverse manners. Multiple nutritional effects on tumors are mediated by dietary modulation of commensals, residing in mucosal surfaces and possibly also within the tumor microenvironment. Mechanistically understanding such diet-microbiome-host interactions may enable to develop precision nutritional interventions impacting cancer development, dissemination, and treatment responses. However, data-driven nutritional strategies integrating diet-microbiome interactions are infrequently incorporated into cancer prevention and treatment schemes. Herein, we discuss how dietary composition affects cancer-related processes through alterations exerted by specific nutrients and complex foods on the microbiome. We highlight how dietary timing, including time-restricted feeding, impacts microbial function in modulating cancer and its therapy. We review existing and experimental nutritional approaches aimed at enhancing microbiome-mediated cancer treatment responsiveness while minimizing adverse effects, and address challenges and prospects in integrating diet-microbiome interactions into precision oncology. Collectively, mechanistically understanding diet-microbiome-host interactomes may enable to achieve a personalized and microbiome-informed optimization of nutritional cancer interventions.

Clinical management of autoimmune liver diseases: juncture, opportunities, and challenges ahead

The three major autoimmune liver diseases are autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC).These conditions are assumed to result from a breakdown in immunological tolerance, which leads to an inflammatory process that causes liver damage.The self-attack is started by T-helper cell-mediated identification of liver autoantigens and B-cell production of autoantibodies,and it is maintained by a reduction in the number and activity of regulatory T-cells.Infections and environmental factors have been explored as triggering factors for these conditions, in addition to a genetic predisposition.Allelic mutations in the HLA locus have been linked to vulnerability, as have relationships with single nucleotide polymorphisms in non-HLA genes.Despite the advances in the management of these diseases, there is no curative treatment for these disorders, and a significant number of patients eventually progress to an end-stage liver disease requiring liver transplantation.In this line, tailored immune-therapeutics have emerged as possible treatments to control the disease.In addition, early diagnosis and treatment are pivotal for reducing the long-lasting effects of these conditions and their burden on quality of life.Herein we present a review of the etiology, clinical presentation, diagnosis, and challenges on ALDs and the feasible solutions for these complex diseases.

Microenvironmental control of the ductular reaction: balancing repair and disease progression

The ductular reaction (DR) is a dynamic adaptive cellular response within the liver, triggered by various hepatic insults and characterized by an expansion of dysmorphic biliary epithelial cells and liver progenitors. This complex response presents a dual role, playing a pivotal function in liver regeneration but, paradoxically, contributing to the progression of liver diseases, depending upon specific contextual factors and signaling pathways involved. This comprehensive review aims to offer a holistic perspective on the DR, focusing into its intricate cellular and molecular mechanisms, highlighting its pathological significance, and exploring its potential therapeutic implications. An up-to-date understanding of the DR in the context of different liver injuries is provided, analyzing its contributions to liver regeneration, inflammation, fibrosis, and ultimately carcinogenesis. Moreover, the review highlights the role of multiple microenvironmental factors, including the influence of extracellular matrix, tissue mechanics and the interplay with the intricate hepatic cell ecosystem in shaping the DR's regulation. Finally, in vitro and in vivo experimental models of the DR will be discussed, providing insights into how researchers can study and manipulate this critical cellular response. By comprehensively addressing the multifaceted nature of the DR, this review contributes to a more profound understanding of its pathophysiological role in liver diseases, thus offering potential therapeutic avenues for hepatic disorders and improving patient outcomes.

Faecal Cytolysin is Associated With Worse Survival in Patients With Primary Sclerosing Cholangitis

BACKGROUND AND AIMS

Primary sclerosing cholangitis (PSC) is an immune-related cholangiopathy without treatment options beyond liver transplantation. The gut-liver axis, especially the role of gut microbes, has emerged as a crucial pathway contributing to PSC pathogenesis. Recent research has revealed Enterococcus (E.) faecalis and its virulence factor cytolysin to increase mortality risk in patients with alcohol-associated hepatitis. Thus, we studied the role of enterococci, particularly E. faecalis and its virulence factor genes cytolysin and gelatinase, in faecal samples from patients with PSC.

METHODS

To assess the relevance of Enterococcus species, we performed 16S rRNA gene amplicon analysis in faecal samples from 60 patients with PSC. We validated our findings by qPCR of faecal microbial DNA in an extended cohort of 105 patients with PSC, 104 patients with inflammatory bowel disease (IBD) and 68 healthy subjects.

RESULTS

High-throughput 16S rRNA amplicon analysis revealed an increased relative abundance of enterococci in PSC patients compared with healthy controls and IBD patients, respectively, (p < 0.0001). PSC patients with high enterococci abundance had a decreased probability of transplant-free survival (p = 0.028). E. faecalis and its virulence factors cytolysin and gelatinase were more abundant in patients with PSC. Higher faecal cytolysin was associated with lower overall survival (p = 0.04), while survival was independent of gelatinase levels.

CONCLUSION

Our data highlight the association of E. faecalis and faecal cytolysin with lower survival in patients with PSC. These data should prompt further research into the pathogenic role of cytolysin-positive E. faecalis, and to explore its role as a potential therapeutic target.

Mutational Analysis of Bile Cell-Free DNA in Primary Sclerosing Cholangitis: A Pilot Study

BACKGROUND

Primary sclerosing cholangitis (PSC) is a chronic liver disease characterised by inflammation and fibrosis of the bile ducts, conferring an increased risk of cholangiocarcinoma (CCA). However, detecting CCA early in PSC patients remains challenging due to the limited sensitivity of conventional diagnostic methods, including imaging or bile duct brush cytology during endoscopic retrograde cholangiopancreatography (ERCP). This study aims to evaluate the potential of bile cell-free DNA (cfDNA) mutational analysis, termed the Bilemut assay, as a tool for CCA detection in PSC patients.

METHODS

Sixty-three PSC patients undergoing ERCP due to biliary strictures were prospectively recruited. Bile samples were collected, and cfDNA was extracted and analysed using the Oncomine Pan-Cancer Cell-Free assay. Twenty healthy liver donors were included for comparison. Samples with a mutant allele frequency (MAF) ≥ 0.1% were considered positive. Correlations between mutational status and clinical characteristics were assessed.

RESULTS

cfDNA mutational analysis was successful in all bile samples. Mutations predominantly in KRAS, GNAS, and TP53 were detected in 36.5% (23/63) of PSC patients, compared to 10% (2/20) of healthy donors (p = 0.0269). The clinical characteristics of Bilemut-positive and -negative patients were comparable, though there was a trend towards a lower prevalence of inflammatory bowel disease in the Bilemut-positive group. Among PSC patients diagnosed with CCA during follow-up, 75% were Bilemut-positive, suggesting an association between mutational status and malignancy risk.

CONCLUSIONS

Mutational analysis of cfDNA obtained from bile collected from PSC patients undergoing ERCP is feasible. Implementing the Bilemut assay may help identify patients needing closer surveillance and further imaging studies.

Unique clinical, morphological, and molecular characteristics of tumors associated with PSC-IBD

Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease characterized by chronic inflammation and progressive fibrosis of the biliary tree, leading to significant liver function impairment over time. There is a strong association with inflammatory bowel diseases (IBD), together representing a distinct and complex medical condition. Patients with PSC-IBD face a heightened risk of various cancers, particularly colorectal carcinoma (CRC) and cholangiocarcinoma (CCA) as the most common types. In this review, we aim to characterize the distinctive features of PSC-IBD-associated carcinomas. Cancer pathogenesis in PSC-IBD is shaped by various factors including dysregulated bile acid metabolism, gut dysbiosis, and unique immune responses. PSC-IBD-associated CRC is often right-sided and warrants vigilant monitoring due to its higher incidence and unique morphological features compared to CRC arising in the terrain of IBD alone. CCA shares substantial genetic similarities with extrahepatic CCA and poses diagnostic challenges since it is frequently detected at advanced stages due to symptom overlap with PSC. Besides, reliable predictive biomarkers for targeted therapy remain largely unexplored. The distinct molecular, genetic, and histopathological profiles of CRC and CCA in PSC-IBD underscore the complexity of these malignancies and highlight the need for continued research to develop precise therapeutic strategies.

β-sitosterol protects against ANIT-induced hepatotoxicity and cholestasis via FXR activation

Cholestasis, a condition marked by bile acid accumulation in the liver and body systems, leads to liver dysfunction and cirrhosis. Currently, ursodeoxycholic acid (UDCA) and obeticholic acid (OCA) are the only two FDA-approved drugs for Cholestasis. Thus, new therapeutic approaches need to be developed. In this study, we validated the liver-protective properties of β-sitosterol (SIT), a key bioactive element abundant in plants, against hepatic toxicity and cholestasis induced by alpha-naphthylisothiocyanate(ANIT), while elucidating its mechanisms of action both in vivo and in vitro. SIT's FXR activation was confirmed via molecular docking and dual-luciferase assays. In the mechanisms of SIT hepatoprotection, the expression levels of bile salt export pump (Bsep) and multidrug resistance protein2 (Mrp2) which are bile acid efflux transporter, and sulfate transferase 2a1 (Sult2a1) which is a bile acid metabolizing enzyme were all increased by SIT, whereas the expression of uptake transporter sodium taurocholate transporting polypeptide (Ntcp), bile acid synthesis enzyme cholesterol 7α-hydroxylase (Cyp7a1) and oxysterol 12α-hydroxylase (Cyp8b1) was decreased by SIT. In addition, SIT alleviated liver inflammation by suppressing inflammatory factor expression. However, FXR antagonist guggulsterone and FXR siRNA abolished SIT's improvements in liver histology, bile acid transporters, and enzymes. Conclusively, through activating FXR, SIT provides a protective effect against hepatotoxicity and cholestasis. SIT might serve as a new potential therapeutic strategy for the treatment of cholestatic liver diseases.

Diagnostic Approach to Abnormal Alkaline Phosphatase Value

Alkaline phosphatase (ALP) is abundantly represented in nature, being fundamental for a number of processes. In addition to its fundamental function in skeletal mineralization, its roles in the pathogenesis of other diseases are being explored. The measurement of total ALP activity in serum or in plasma is a useful biomarker in clinical practice. Indeed, routine measurement of serum total ALP is a long-standing established part of initial biochemical evaluation of patients both in the hospital setting and on an ambulatory basis. Raised or reduced values of this enzyme activity are indicative of a number of diseases, most commonly affecting the skeleton and the biliary tract. Electrophoretic assays are preferable for visualizing and investigating the cause of increased serum total ALP activities, and bone ALP immunoassays are preferable for investigating and monitoring individuals with bone and mineral metabolic abnormalities. Here, we give a holistic vision of this fundamental enzyme, suggesting a clinical approach to the identification of diseases causing abnormal values. Finally, a therapeutic role has emerged as substitutive therapy in patients with hypophosphatasia, even though ongoing and future studies are exploring its role in other therapeutic areas. This narrative review was based on articles found by searching PubMed from its inception until July 2024 for the terms alkaline phosphatases, isozymes, isoforms, bone alkaline phosphatase, liver alkaline phosphatase, intestinal alkaline phosphatase, placental alkaline phosphatase, liver function tests, γ-glutamyltransferase, skeletal diseases, and liver diseases. We limited our research to papers published in the English language, with emphasis placed on those describing differential diagnosis whenever available.

Performance of the Mayo Risk Score in Predicting Transplant and Mortality in a Single-Center U.S. Cohort of Primary Sclerosing Cholangitis

Background: The Mayo Risk Score (MRS) predicts short-term mortality in primary sclerosing cholangitis (PSC) using the age, bilirubin, albumin, aspartate aminotransferase (AST), and variceal bleeding history. While the MRS has been validated in end-stage PSC, its ability to predict liver transplantation (LT) and outcomes in newly diagnosed patients without advanced disease remains unclear. This study evaluated the effectiveness of the MRS in predicting LT and mortality in this patient population. Methods: We analyzed data from 109 adults with PSC enrolled in a prospective registry (2018-2024) with ≥4 years of follow-up. Logistic regression identified the predictors of LT or death, and the model performance was assessed using the area under the receiver operating characteristic curve (AUROC). Multicollinearity was evaluated using the variance inflation factor (VIF). Results: Among the 109 patients (mean age 45 ± 15 years, 51% female), 85% remained alive without LT, 12% underwent LT, and 3% died over a median follow-up of 4.63 years. The MRS was significantly associated with LT or death (OR 3.08, p < 0.001) and demonstrated excellent predictive performance (AUROC 0.99, p < 0.001). The model achieved 95.45% sensitivity, 98.85% specificity, and a correct classification rate of 98.17%, supporting its clinical utility. Conclusion: The MRS is a robust tool for risk stratification in PSC, predicting LT and mortality. These findings highlight its broader applicability beyond end-stage PSC and underscore its potential for guiding clinical management and early intervention strategies.

Development of the natural history component of an early economic model for primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is a rare, chronic cholestatic disease that can progress to cirrhosis and liver failure. The natural history of PSC is variable as liver enzymes and liver symptoms fluctuate over time. Several drugs for PSC are under investigation, but there are currently no economic models to evaluate the cost-effectiveness and value of new treatments. The objective of this study was to develop an early economic model for PSC and validate the natural history component.

METHODS

A lifetime horizon Markov cohort model was developed to track the progression of adults with PSC with or without inflammatory bowel disease. Based on relevant literature and clinical expert advice, fibrosis staging was used to model disease progression. Evidence on disease progression, mortality, PSC-related complications, and secondary cancers was identified by literature searches and validated by interviews with clinical and cost-effectiveness modelling experts. Model outcomes were overall survival and transplant-free survival years, and the proportions of patients receiving liver transplants, 2nd liver transplants after recurrent PSC (rPSC), and developing rPSC after liver transplantation during their lifetime. Cumulative incidence of secondary cancers and quality-adjusted life-years (QALYs) were also tracked.

RESULTS

Model outcomes are in line with estimates reported in literature recommended by clinical experts. Overall survival (95% uncertainty interval [UI]) was estimated to be 25.0 (23.2-26.3) years and transplant-free survival was estimated to be 22.0 (20.2-23.6) years. The estimated proportion (95% UI) of patients receiving first liver transplants was 14.5% (11.6-17.1%), while the proportion of patients developing rPSC and receiving 2nd liver transplants after rPSC was 24.2% (20.4-28.0%) and 21.6% (12.9-29.7%), respectively. The cumulative incidence (95% UI) of cholangiocarcinoma, colorectal cancer, and gallbladder cancer were estimated at 5.2% (2.1-10.0%), 3.6% (1.4-5.4%), and 3.3% (1.2-7.6%), respectively. Discounted lifetime QALYs per patient (95% UI) were estimated at 16.4 (15.6-17.1).

CONCLUSIONS

We have developed a model framework to simulate the progression of PSC with estimates of overall and transplant-free survival. This model, which calibrates well with existing estimates of disease progression, may be useful to evaluate the clinical and economic benefits of future treatments.

Design, synthesis, and biological evaluation of imidazolidinone derivatives as potent PPARα/δ agonists for the treatment of cholestatic liver diseases

Cholestatic liver disease (CLD) represents a significant and growing public health concern, and there is a lack of effective therapeutic drug in clinical practice. Peroxisome proliferator-activator receptors α/δ (PPARα/δ) are regarded as potential therapeutic targets for CLD. In this study, a series of novel imidazolidinone PPARα/δ agonists were developed, and the preferred compound 8 displayed potent and well-balanced agonistic activity. Compound 8 showed high selectivity over other related nuclear receptors and effectively regulated the PPARα/δ target genes expression in mice. Notably, compound 8 demonstrated good pharmacokinetic profiles and potent in vivo anti-CLD effects. Collectively, compound 8 holds promise for developing an anti-CLD agent.

Primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic biliary inflammation associated with periductular fibrosis of the intrahepatic and extrahepatic bile ducts leading to strictures, bacterial cholangitis, decompensated liver disease and need for liver transplantation. This rare focal liver disease affects all races and ages, with a predominance of young males. There is an up to 88% association with inflammatory bowel disease. Although the aetiology is unknown and the pathophysiology is poorly understood, PSC is regarded as an autoimmune liver disease based on a strong immunogenetic background. Further, the associated risk for various malignancies, particularly cholangiocellular carcinoma, is also poorly understood. No medical therapy has been approved so far nor has been shown to improve transplant-free survival. However, ursodeoxycholic acid is widely used since it improves the biochemical parameters of cholestasis and is safe at low doses. MRI of the biliary tract is the primary imaging technology for diagnosis. Endoscopic interventions of the bile ducts should be limited to clinically relevant strictures for balloon dilatation, biopsy and brush cytology. End-stage liver disease with decompensation is an indication for liver transplantation with recurrent PSC in up to 38% of patients. Several novel therapeutic strategies are in various stages of development, including apical sodium-dependent bile acid transporter and ileal bile acid transporter inhibitors, integrin inhibitors, peroxisome proliferator-activated receptor agonists, CCL24 blockers, recombinant FGF19, CCR2/CCR5 inhibitors, farnesoid X receptor bile acid receptor agonists, and nor-ursodeoxycholic acid. Manipulation of the gut microbiome includes faecal microbiota transplantation. This article summarizes present knowledge and defines unmet medical needs to improve quality of life and survival.

24-Nor-ursodeoxycholic acid improves intestinal inflammation by targeting TH17 pathogenicity and transdifferentiation

BACKGROUND

24-Nor-ursodeoxycholic acid (NorUDCA) is a novel therapeutic bile acid for treating immune-mediated cholestatic liver diseases, such as primary sclerosing cholangitis (PSC).

OBJECTIVE

Since PSC strongly associates with T helper-type-like 17 (TH17)-mediated intestinal inflammation, we explored NorUDCA's immunomodulatory potential on TH17 cells.

DESIGN

NorUDCA's impact on TH17 differentiation was assessed using a CD4+TNaive adoptive transfer mouse model, and on intraepithelial TH17 pathogenicity and transdifferentiation using an αCD3 stimulation model combined with interleukin-17A-fate-mapping. Mechanistic studies used molecular and multiomics approaches, flow cytometry and metabolic assays with pathogenic (p) TH17. Pathogenicity of pTH17 exposed to NorUDCA in vitro was evaluated following adoptive transfer in intestinal tissues or the central nervous system (CNS). Key findings were validated in an αCD3-stimulated humanised NSG mouse model reconstituted with peripheral blood mononuclear cells from patients with PSC.

RESULTS

NorUDCA suppressed TH17 effector function and enriched regulatory T cell (Treg) abundance upon CD4+TNaive cell transfer. NorUDCA mitigated intraepithelial TH17 pathogenicity and decreased the generation of proinflammatory 'TH1-like-TH17' cells, and enhanced TH17 transdifferentiation into Treg and Tr1 (regulatory type 1) cells in the αCD3-model. In vivo ablation revealed that Treg induction is crucial for NorUDCA's anti-inflammatory effect on TH17 pathogenicity. Mechanistically, NorUDCA restrained pTH17 effector function and simultaneously promoted functional Treg formation in vitro, by attenuating a glutamine-mTORC1-glycolysis signalling axis. Exposure of pTH17 to NorUDCA dampened their pathogenicity and expansion in the intestine or CNS upon transfer. NorUDCA's impact on TH17 inflammation was corroborated in the humanised NSG mouse model.

CONCLUSION

NorUDCA restricts TH17 inflammation in multiple mouse models, potentiating future clinical applications for treating TH17-mediated intestinal diseases and beyond.

Screening the human druggable genome identifies ABHD17B as an anti-fibrotic target in hepatic stellate cells

Hepatic stellate cells (HSCs) are activated with chronic liver injury and transdifferentiate into myofibroblasts, which produce excessive extracellular matrices that form the fibrotic scar. While the progression of fibrosis is understood to be the cause of end-stage liver disease, there are no approved therapies directed at interfering with the activity of HSC myofibroblasts. Here, we perform a high-throughput small interfering RNA (siRNA) screen in primary human HSC myofibroblasts to identify gene products necessary for the fibrotic phenotype of HSCs. We find that depletion of ABHD17B promotes the inactivation of HSCs, characterized by reduced COL1A1 and ACTA2 expression and accumulation of lipid droplets. Mice deficient in Abhd17b are also protected from fibrosis in the setting of in vivo liver injury. While ABHD17B is a depalmitoylase, our data suggest that ABHD17B promotes fibrosis through pathways independent of depalmitoylation that include interaction with MYO1B to modulate gene expression and HSC migration. Together, our results provide an analysis of the phenotypic consequences for siRNAs targeting RNAs from >9500 genes in primary human HSCs and identify ABHD17B as a potential therapeutic target to inhibit liver fibrosis.

Bile acids and their receptors in hepatic immunity

Similarly to conventional steroids, bile acids function as signaling molecules, acting on a family of membrane and nuclear receptors. The best-characterized bile acid-regulated receptors are the farnesoid X receptor, activated by primary bile acids, and the G-protein-coupled bile acid receptor 1 (also known as Takeda G protein-coupled receptor 5), which is activated by secondary bile acids, such as lithocholic acid (LCA) and deoxycholic acid. Both the farnesoid X receptor and G-protein-coupled bile acid receptor 1 are expressed in cells of innate immunity, monocytes/macrophages, and natural killer cells. Their activation in these cells provides counter-regulatory signals that are inhibitory in nature and attenuate inflammation. In recent years, however, it has been increasingly appreciated that bile acids biotransformations by intestinal microbiota result in the formation of chemically different secondary bile acids that potently regulate adaptive immunity. The 3-oxoLCA and isoalloLCA, two LCA derivatives, bind receptors such as the retinoic acid receptor-related orphan receptor gamma t (RORγt) and the vitamin D receptor (VDR) that are expressed only by lymphoid cells, extending the regulatory role of bile acids to T cells, including T-helper 17 cells and type 3 innate lymphoid cells (ILC3). In this novel conceptual framework, bile acids have emerged as one of the main components of the postbiota, the waste array of chemical mediators generated by the intestinal microbiota. Deciphering the interaction of these mediators with the immune system in the intestine and liver is a novel and fascinating area of bile acid renaissance.

Liver transcriptome analysis reveals PSC-attributed gene set associated with fibrosis progression

Background & Aims

Primary sclerosing cholangitis (PSC) is a chronic heterogenous cholangiopathy with unknown etiology where chronic inflammation of the bile ducts leads to multifocal biliary strictures and biliary fibrosis with consecutive cirrhosis development. We here aimed to identify a PSC-specific gene signature associated with biliary fibrosis development.

Methods

We performed RNA-sequencing of 47 liver biopsies from people with PSC (n = 16), primary biliary cholangitis (PBC, n = 15), and metabolic dysfunction-associated steatotic liver disease (MASLD, n = 16) with different fibrosis stages to identify a PSC-specific gene signature associated with biliary fibrosis progression. For validation, we compared an external transcriptome data set of liver biopsies from people with PSC (n = 73) with different fibrosis stages (baseline samples from NCT01672853).

Results

Differential gene expression analysis of the liver transcriptome from patients with PSC with advanced vs. early fibrosis revealed 431 genes associated with fibrosis development. Of those, 367 were identified as PSC-associated when compared with PBC or MASLD. Validation against an external data set of 73 liver biopsies from patients with PSC with different fibrosis stages led to a condensed set of 150 (out of 367) differentially expressed genes. Cell type specificity assignment of those genes by using published single-cell RNA-Seq data revealed genetic disease drivers expressed by cholangiocytes (e.g. CXCL1, SPP1), fibroblasts, innate, and adaptive immune cells while deconvolution along fibrosis progression of the PSC, PBC, and MASLD samples highlighted an early involvement of macrophage- and neutrophil-associated genes in PSC fibrosis.

Conclusions

We reveal a PSC-attributed gene signature associated with biliary fibrosis development that may enable the identification of potential new biomarkers and therapeutic targets in PSC-related fibrogenesis.

Impact and implications

Primary sclerosing cholangitis (PSC) is an inflammatory liver disease that is characterized by multifocal inflammation of bile ducts and subsequent biliary fibrosis. Herein, we identify a PSC-specific gene set of biliary fibrosis progression attributing to a uniquely complex milieu of different cell types, including innate and adaptive immune cells while neutrophils and macrophages showed an earlier involvement in fibrosis initiation in PSC in contrast to PBC and metabolic dysfunction-associated steatotic liver disease. Thus, our unbiased approach lays an important groundwork for further mechanistic studies for research into PSC-specific fibrosis.

Cholecystectomy Is Linked to Worse Clinical Outcomes in Primary Sclerosing Cholangitis

Recent findings have suggested that gallbladder-derived retinoic acid signaling plays a crucial role in the regeneration of damaged intrahepatic biliary ducts. This retrospective cohort study analyzed the clinical records of 20 patients with primary sclerosing cholangitis (PSC) treated at our hospital between 2013 and 2024. We investigated the clinical implications of gallbladder removal in patients with PSC, a progressive cholangiopathy with limited therapeutic options. We retrospectively analyzed the data of patients with PSC and compared patients with and without prior cholecystectomy to assess the impact on disease progression using the Mayo risk score, Fibrosis-4 (FIB4) index, and other clinical parameters. Our findings indicated that cholecystectomy was associated with worse Mayo risk scores (p = 0.0004) and an elevated FIB4 index (p = 0.021), suggesting a potential link between gallbladder removal and accelerated disease progression. Furthermore, mortality and transplant-free survival analysis revealed significantly worse outcomes in the cholecystectomy group (odds ratio = 21.0, p = 0.032). However, given the retrospective nature and small sample size of this study, selection bias cannot be excluded, and further research is needed to confirm these findings. These findings support the hypothesis that gallbladder-derived factors, such as retinoic acid, may influence PSC progression and highlight the need for further research into therapeutic interventions targeting this pathway.

Natural History and Predictors of Clinical Outcomes in Autoimmune Liver Diseases: A Multicenter Study

BACKGROUND AND AIM

Prognosis in autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) has historically been poor. This multicenter retrospective cohort study investigated the natural history and assessed the predictors of outcomes in patients with AIH, PBC, and PSC.

METHODS

AIH, PBC, and PSC patients were identified from the state-wide Hepascore and Clinical Outcome cohort. Overall death or transplant, liver-related mortality (liver-related death or transplant), and liver-related decompensation were determined using a population-based data linkage system. Baseline Liver Outcome Score (LOS), Hepascore, and MELD were examined for predicting outcomes.

RESULTS

Two-hundred thirty-seven AIH patients (24% male, median age 56.6 years [range, 14.3-94.0]), 157 PBC patients (8.3% male, median age 60.5 years [range, 25.6-87.1]), and 167 PSC patients (52.7% male, median age 55.6 years [range, 18.4-88.6]) were enrolled. Five-year transplant-free survival was 88% (95%CI: 81-92%) in AIH, 92% (95%CI: 85-96%) in PBC, and 61% (95%CI: 51-69%) in PSC. PSC had a significantly worse overall death or transplant, liver-related mortality, and liver-related decompensation when compared to AIH and PBC (p < 0.0001). LOS was a significant independent predictor of overall death or transplant, liver-related mortality, and liver-related decompensation among patients with AIH and PBC. LOS was a significant independent predictor of overall death or transplant in patients with PSC, and Hepascore was a significant independent predictor of liver-related mortality and liver-related decompensation.

CONCLUSIONS

Outcomes for AIH and PBC are excellent but remain poor in PSC. LOS is a predictor of outcomes in autoimmune liver disease.

A Closer Look into Autoimmune Liver Diseases

Autoimmune liver diseases involve a heterogeneous group of chronic inflammatory disorders, including autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. Sometimes presented consistently as an overlapping syndrome, their pathogenesis is rather complex and has yet to be fully elucidated, despite extensive research efforts. This review article corroborates the molecular mechanisms of autoimmune liver diseases, as well as existing and potential therapeutic modalities.

Open Label Vancomycin in Primary Sclerosing Cholangitis-Inflammatory Bowel Disease: Improved Colonic Disease Activity and Associations With Changes in Host-Microbiome-Metabolomic Signatures

BACKGROUND

We conducted a single-arm interventional study, to explore mucosal changes associated with clinical remission under oral vancomycin (OV) treatment, in primary sclerosing cholangitis-associated inflammatory bowel disease (PSC-IBD); NCT05376228.

METHODS

Fifteen patients with PSC and active colitis (median fecal calprotectin 459 µg/g; median total Mayo score 5) were treated with OV (125 mg QID) for 4 weeks and followed-up for a further 4 weeks of treatment withdrawal (8 weeks, end-of-study). Colonic biopsies were obtained at baseline and Week 4. Clinical assessments, and serum and stool samples (metagenomics, metatranscriptomics, and metabolomics) were collected at Weeks 0, 2, 4, and 8. The primary efficacy outcome measure was the induction of clinical remission.

RESULTS

Oral vancomycin resulted in clinical remission in 12/15 patients and significant reductions in fecal calprotectin. Oral vancomycin was associated with reduced abundances of Lachnospiraceae, genera Blautia and Bacteroides; and enrichment of Enterobacteriaceae, and genera Veillonella, Akkermansia, and Escherichia. Oral vancomycin treatment was associated with the downregulation of multiple metatranscriptomic pathways (including short-chain fatty acid [SCFA] metabolism and bile acid [BA] biotransformation), along with host genes and multiple pathways involved in inflammatory responses and antimicrobial defence; and an upregulation of genes associated with extracellular matrix repair. Oral vancomycin use resulted in the loss of specific fecal SCFAs and secondary BAs, including lithocholic acid derivatives. Colitis activity relapsed following OV withdrawal, with host mucosal and microbial changes trending toward baseline.

CONCLUSIONS

Four weeks of OV induces remission in PSC-IBD activity, associated with a reduction in gut bacterial diversity and compositional changes relating to BA and SCFA homeostasis.

Integrin αVβ6: Autoantigen and Driver of Epithelial Remodeling in Colon and Bile Ducts in Primary Sclerosing Cholangitis and Inflammatory Bowel Disease

BACKGROUND

Recently, autoantibodies directed against the epithelial adhesion protein integrin αVβ6 have been identified that are strongly associated with ulcerative colitis (UC). We aimed to elucidate whether anti-integrin αVβ6 (anti-αVβ6) is present in primary sclerosing cholangitis (PSC), its associated inflammatory bowel disease, or other cholestatic liver diseases and their persistence after proctocolectomy.

METHODS

We detected anti-αVβ6 by an enzyme-linked immunosorbent assay in sera collected at 2 German tertiary centers, including healthy controls (N = 62), UC (N = 36), Crohn's disease (CD, N = 65), PSC-inflammatory bowel diseases (IBD) (78 samples from N = 41 patients), PSC without IBD (PSC, 41 samples from N = 18 patients), primary biliary cholangitis (PBC, N = 24), autoimmune hepatitis (AIH, N = 32), secondary sclerosing cholangitis (SSC, N = 12), and metabolic dysfunction-associated steatotic liver disease (MASLD, N = 24). In addition, sera after proctocolectomy were studied (44 samples/N = 10 patients). Immunofluorescent analyses were performed in tissue samples from liver, large bile duct from surgical resections, and colon of PSC patients.

RESULTS

Anti-αVβ6 occurred in 91% of UC, 17% of CD, 73% of PSC-IBD, 39% of PSC, 4% of PBC, 14% of AIH, and 0% of healthy controls, SSC, or MASLD. Integrin αVβ6 is selectively expressed in disease-associated epithelia of both bile duct and colon. Anti-αVβ6 levels correlate moderately with intestinal disease activity in PSC-IBD, but only weakly with biliary disease.

CONCLUSIONS

Anti-αVβ6 frequently occurs in patients suffering from PSC, especially in PSC-IBD. Anti-αVβ6 levels positively correlate to IBD activity in PSC-IBD, but may also occur in the absence of clinically manifest IBD in PSC.

Immune-mediated liver injury from checkpoint inhibitors: mechanisms, clinical characteristics and management

Immunotherapy has changed the treatment landscape for patients with cancer in the past decade. Immune checkpoint inhibitor (ICI)-based therapies have proven effective in a range of malignancies, including liver and gastrointestinal cancers, but they can cause diverse off-target organ toxicities. With the increasingly wider application of these drugs, immune-mediated liver injury from ICIs has become a commonly encountered challenge in clinical hepatology and gastroenterology. In this Review, we discuss the evidence from human and animal studies on the immunological mechanisms of immune-mediated liver injury from ICIs and summarize its clinical features and practical considerations for its management.

Paediatric-onset autoimmune liver disease: Insights from a monocentric experience

BACKGROUND

Autoimmune liver disease (AILD) encompasses autoimmune hepatitis (AIH), autoimmune sclerosing cholangitis (ASC) and primary sclerosing cholangitis (PSC). A unified disease process evolving over time through these entities has been recently suggested. From this perspective, this study aimed to compare the characteristics of childhood-onset AILD at baseline and after a medium-to-long term follow-up period.

METHODS

Paediatric-onset cases of AILD diagnosed between 1992 and 2023 at a tertiary-care centre were reviewed. Patients transitioned to adult-care by the time of data collection were asked for clinical updates.

RESULTS

Fifty-five patients were included (AIH = 20, ASC =22, PSC =13). AIH, ASC and PSC exhibited increasing age at the onset (AIH to PSC, p < 0.01). The area under the receiver operating characteristic curve for gamma-glutamyltranspeptidase (GGT) combined with alkaline phosphatase/aspartate aminotransferase (ALP/AST) ratio in predicting sclerosing cholangitis was 0.94, with a sensitivity of 86 % and a specificity of 94 %. At the last follow-up (median duration 5,8 years, interquartile range [IQR] 2,9-10,2, n = 45), 15 patients (33 %) developed portal hypertension, 2 patients (4 %) underwent liver transplantation, no patient died.

CONCLUSION

A cohort of childhood-onset AILD managed at a single centre reveals a temporal trend in the onset of AIH, ASC and PSC, with progressively older ages. Elevated GGT levels combined with a high ALP/AST ratio predict the diagnosis of sclerosing cholangitis. The occurrence of liver-related adverse events in one-third of patients highlights the progressive nature of paediatric-onset AILD.

Mitochondrial dysfunction and lipid alterations in primary sclerosing cholangitis

OBJECTIVES

Indications of mitochondrial dysfunction are commonly seen in liver diseases, but data are scarce in primary sclerosing cholangitis (PSC). Analyzing circulating and liver-resident molecules indirectly reflecting mitochondrial dysfunction, we aimed to comprehensively characterize this deficit in PSC, and whether this was PSC specific or associated with cholestasis.

MATERIALS AND METHODS

We retrospectively included plasma from 191 non-transplant patients with large-duct PSC and 100 healthy controls and explanted liver tissue extracts from 24 PSC patients and 18 non-cholestatic liver disease controls. Using mass spectroscopy, we profiled lipids and fatty acids, carnitine, acylcarnitines, and metabolites in the tryptophan-kynurenine-nicotinamide pathway.

RESULTS

Hierarchal clustering of fatty acid levels identified patients with PSC and healthy controls as separate clusters. Compared to healthy controls, PSC patients had increased levels of monounsaturated fatty acids (MUFA) and palmitate (C16:0) in plasma, but reduced levels of long-chain saturated fatty acids (SFAs). These findings were more pronounced in PSC patients with cholestasis. Several n-3 polyunsaturated fatty acids were elevated in PSC but not associated with cholestasis. Acylcarnitine ratios C2/C5 and C2/C3 were elevated while C2/C16 was reduced in PSC, indicating impaired mitochondrial fatty acid oxidation of medium-long chained fatty acids. Levels of intermediates in the tryptophan-kynurenine pathway indicated impaired NAD biosynthesis, suggesting impaired energy supply to mitochondria in PSC.

CONCLUSIONS

We found that mitochondrial dysfunction was prominent in PSC and associated with increasing cholestasis. Whether this is merely a marker of liver disease and severity, or an underlying driver and potential therapeutic target in PSC remains to be explored.

The Role of Sulfatides in Liver Health and Disease

Sulfatides or 3-O-sulfogalactosylceramide are negatively charged sulfated glycosphingolipids abundant in the brain and kidneys and play crucial roles in nerve impulse conduction and urinary pH regulation. Sulfatides are present in the liver, specifically in the biliary tract. Sulfatides are self-lipid antigens presented by cholangiocytes to activate cluster of differentiation 1d (CD1d)-restricted type II natural killer T (NKT) cells. These cells are involved in alcohol-related liver disease (ArLD) and ischemic liver injury and exert anti-inflammatory effects by regulating the activity of pro-inflammatory type I NKT cells. Loss of sulfatides has been implicated in the chronic inflammatory disorder of the liver known as primary sclerosing cholangitis (PSC); bile ducts deficient in sulfatides increase their permeability, resulting in the spread of bile into the liver parenchyma. Previous studies have shown elevated levels of sulfatides in hepatocellular carcinoma (HCC), where sulfatides could act as adhesive molecules that contribute to cancer metastasis. We have recently demonstrated how loss of function of GAL3ST1, a limiting enzyme involved in sulfatide synthesis, reduces tumorigenic capacity in cholangiocarcinoma (CCA) cells. The biological function of sulfatides in the liver is still unclear; however, this review aims to summarize the existing findings on the topic.

Current Treatment Regimens and Promising Molecular Therapies for Chronic Hepatobiliary Diseases

Chronic hepatobiliary damage progressively leads to fibrosis, which may evolve into cirrhosis and/or hepatocellular carcinoma. The fight against the increasing incidence of liver-related morbidity and mortality is challenged by a lack of clinically validated early-stage biomarkers and the limited availability of effective anti-fibrotic therapies. Current research is focused on uncovering the pathogenetic mechanisms that drive liver fibrosis. Drugs targeting molecular pathways involved in chronic hepatobiliary diseases, such as inflammation, hepatic stellate cell activation and proliferation, and extracellular matrix production, are being developed. Etiology-specific treatments, such as those for hepatitis B and C viruses, are already in clinical use, and efforts to develop new, targeted therapies for other chronic hepatobiliary diseases are ongoing. In this review, we highlight the major molecular changes occurring in patients affected by metabolic dysfunction-associated steatotic liver disease, viral hepatitis (Delta virus), and autoimmune chronic liver diseases (autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis). Further, we describe how this knowledge is linked to current molecular therapies as well as ongoing preclinical and clinical research on novel targeting strategies, including nucleic acid-, mesenchymal stromal/stem cell-, and extracellular vesicle-based options. Much clinical development is obviously still missing, but the plethora of promising potential treatment strategies in chronic hepatobiliary diseases holds promise for a future reversal of the current increase in morbidity and mortality in this group of patients.

CCL24 and Fibrosis: A Narrative Review of Existing Evidence and Mechanisms

Tissue fibrosis results from a dysregulated and chronic wound healing response accompanied by chronic inflammation and angiogenesis. Regardless of the affected organ, fibrosis shares the following common hallmarks: the recruitment of immune cells, fibroblast activation/proliferation, and excessive extracellular matrix deposition. Chemokines play a pivotal role in initiating and advancing these fibrotic processes. CCL24 (eotaxin-2) is a chemokine secreted by immune cells and epithelial cells, which promotes the trafficking of immune cells and the activation of profibrotic cells through CCR3 receptor binding. Higher levels of CCL24 and CCR3 were found in the tissue and sera of patients with fibro-inflammatory diseases, including primary sclerosing cholangitis (PSC), systemic sclerosis (SSc), and metabolic dysfunction-associated steatohepatitis (MASH). This review delves into the intricate role of CCL24 in fibrotic diseases, highlighting its impact on fibrotic, immune, and vascular pathways. We focus on the preclinical and clinical evidence supporting the therapeutic potential of blocking CCL24 in diseases that involve excessive inflammation and fibrosis.

Quantitative fibrosis identifies biliary tract involvement and is associated with outcomes in pediatric autoimmune liver disease

BACKGROUND

Children with autoimmune liver disease (AILD) may develop fibrosis-related complications necessitating a liver transplant. We hypothesize that tissue-based analysis of liver fibrosis by second harmonic generation (SHG) microscopy with artificial intelligence analysis can yield prognostic biomarkers in AILD.

METHODS

Patients from single-center studies with unstained slides from clinically obtained liver biopsies at AILD diagnosis were identified. Baseline demographics and liver biochemistries at diagnosis and 1 year were collected. Clinical endpoints studied included the presence of varices, variceal bleeding, ascites, HE, and liver transplant. In collaboration with HistoIndex, unstained slides underwent SHG/artificial intelligence analysis to map fibrosis according to 10 quantitative fibrosis parameters based on tissue location, including total, periportal, perisinusoidal, and pericentral area and length of strings.

RESULTS

Sixty-three patients with AIH (51%), primary sclerosing cholangitis (30%), or autoimmune sclerosing cholangitis (19%) at a median of 14 years old (range: 3-24) were included. An unsupervised analysis of quantitative fibrosis parameters representing total and portal fibrosis identified a patient cluster with more primary sclerosing cholangitis/autoimmune sclerosing cholangitis. This group had more fibrosis at diagnosis by METAVIR classification of histopathological review of biopsies (2.5 vs. 2; p = 0.006). This quantitative fibrosis pattern also predicted abnormal 12-month ALT with an OR of 3.6 (1.3-10, p = 0.014), liver complications with an HR of 3.2 (1.3-7.9, p = 0.01), and liver transplantation with an HR of 20.1 (3-135.7, p = 0.002).

CONCLUSIONS

The application of SHG/artificial intelligence algorithms in pediatric-onset AILD provides improved insight into liver histopathology through fibrosis mapping. SHG allows objective identification of patients with biliary tract involvement, which may be associated with a higher risk for refractory disease.

Primary Biliary Cholangitis and Primary Sclerosing Cholangitis Therapy Landscape

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are rare, and chronic cholestatic diseases that can progress to liver failure. The goals of treatment are to halt the progression of liver disease to cirrhosis and/or liver failure, and alleviate symptoms associated with these diseases. Ursodeoxycholic acid has historically been the first-line treatment of PBC, with obeticholic acid and fibrates used as second-line or adjunctive therapies. However, the treatment landscape is rapidly expanding. Recently, 2 new second-line agents gained US Food and Drug Administration approval for the treatment of PBC, and several other therapies remain under investigation with promising results. Although significant progress has been made in the development of therapies for PBC, there are no current approved treatments of PSC other than liver transplantation although several emerging therapies have shown encouraging results. This review outlines the current and upcoming treatments of PBC and PSC.

Acquired ductopenia: an insight into imaging findings

Hepatic ductopenia is a pathologic diagnosis characterized by a decrease in the number of intrahepatic bile ducts as a consequence of various underlying etiologies. Some etiologies, such as primary sclerosing cholangitis, primary biliary cholangitis, and ischemic cholangitis, often have distinctive imaging findings. In contrast, other causes such as chronic rejection following liver transplantation, drug-induced biliary injury, infection, malignancy such as lymphoma, and graft-versus-host disease may only have ancillary or non-specific imaging findings. Thus, diagnosing ductopenia in conditions with nonspecific imaging findings requires a multidimensional approach, including clinical evaluation, serological testing, imaging, and liver histology to identify the underlying cause. These etiologies lead to impaired bile flow, resulting in cholestasis, liver dysfunction, and, ultimately, cirrhosis and liver failure if the underlying cause remains untreated or undetected. In the majority of instances, individuals diagnosed with ductopenia exhibit a positive response to treatment addressing the root cause or cessation of the causative agent. This article focuses on acquired causes of ductopenia, its clinical manifestation, histopathology, imaging diagnosis, and management.

Bile acid metabolism and signalling in liver disease

Bile acids (BAs) serve as signalling molecules, efficiently regulating their own metabolism and transport, as well as key aspects of lipid and glucose homeostasis. BAs shape the gut microbial flora and conversely are metabolised by microbiota. Disruption of BA transport, metabolism and physiological signalling functions contribute to the pathogenesis and progression of a wide range of liver diseases including cholestatic disorders and MASLD (metabolic dysfunction-associated steatotic liver disease), as well as hepatocellular and cholangiocellular carcinoma. Additionally, impaired BA signalling may also affect the intestine and kidney, thereby contributing to failure of gut integrity and driving the progression and complications of portal hypertension, cholemic nephropathy and the development of extrahepatic malignancies such as colorectal cancer. In this review, we will summarise recent advances in the understanding of BA signalling, metabolism and transport, focusing on transcriptional regulation and novel BA-focused therapeutic strategies for cholestatic and metabolic liver diseases.

Safety and efficacy of HK-660S in patients with primary sclerosing cholangitis: A randomized double-blind phase 2a trial

BACKGROUND/AIMS

A clinical unmet need persists for medications capable of modulating the progression of primary sclerosing cholangitis (PSC). This study aimed to assess the clinical feasibility of HK-660S (beta-lapachone) in PSC.

METHODS

In this multicenter, randomized, double-blind, placebo-controlled, parallel-group phase 2 trial, participants were assigned in a 2:1 ratio to receive either 100 mg of HK-660S or a placebo twice daily for 12 weeks. The primary outcomes were the reduction in serum alkaline phosphatase (ALP) levels and the percentage of participants showing improvements in PSC severity, as determined by magnetic resonance cholangiopancreatography with the Anali score. Secondary endpoints included changes in liver stiffness and adverse events.

RESULTS

The analysis included 21 patients, 15 receiving HK-660S, and six receiving a placebo. Improvements in the Anali score were observed in 13.3% of the HK-660S group, with no improvements in the placebo group. HK-660S treatment resulted in a 15.2% reduction in mean ALP levels, compared to a 6.6% reduction in the placebo group. A stratified ad-hoc analysis based on baseline ALP levels showed a statistically significant response in the HK-660S group among those with ALP levels greater than twice the upper limit of normal, with a 50% responder rate (p=0.05). Additionally, 26.7% of the HK-660S group showed improvements in the enhanced liver fibrosis score, with no improvements in the placebo group. HK-660S was generally well tolerated.

CONCLUSION

HK-660S is well tolerated among patients with PSC and may improve bile duct strictures, decrease serum ALP levels, and reduce liver fibrosis (cris.nih.go.kr, Number KCT0006590).

Outcome of Liver Retransplantation in Patients With Primary Sclerosing Cholangitis

BACKGROUND AND AIMS

Primary sclerosing cholangitis (PSC) is among the most common indications for liver transplantation in the Nordic countries and with an increasing trend in Europe and North America. Due to post-transplant complications and high prevalence of disease recurrence this group is at risk of requiring retransplantation (re-LTX). Results from re-LTX for PSC are not extensively studied and there is a lack of knowledge regarding prognosis after re-LTX in this population.

METHODS

Graft and patient survival after re-LTX for patients with PSC and a comparable comparison group from the Nordic liver transplant registry were analysed. One-hundred and eighty-five patients with PSC and 208 patients in the comparison group were included.

RESULTS

The graft and patient survival were better for patients with PSC compared to the comparison group (p < 0.001). Re-LTX for recurrence of PSC (rPSC) compared to other aetiologies had similar and better outcomes for graft and patient survival (p = 0.093 and p = 0.023, respectively). Moreover, re-LTX for rPSC compared to the comparison group had a lower 30-day and 5-year mortality (p < 0.001 and p = 0.041, respectively).

CONCLUSION

Outcomes after retransplantation for PSC were similar or better compared to the comparison group. Retransplantation represents a treatment option with the potential for excellent outcomes in patients with PSC and should be considered in transplanted PSC patients with graft failure.

Cytoskeleton Remodeling-Related Proteins Represent a Specific Salivary Signature in PSC Patients

Primary sclerosing cholangitis (PSC) and Primary biliary cholangitis (PBC) are chronic inflammatory biliary diseases characterized by progressive damage of the bile ducts, resulting in hepatobiliary fibrosis and cirrhosis. Currently, specific biomarkers that allow to distinguish between PSC and PBC do not exist. In this study, we examined the salivary proteome by carrying out a comprehensive and non-invasive screening aimed at highlighting possible quali-quantitative protein deregulations that could be the starting point for the identification of effective biomarkers in future. Saliva samples collected from 6 PBC patients were analyzed using a liquid chromatography-tandem mass spectrometry technique, and the results were compared with those previously obtained in the PSC group. We identified 40 proteins as significantly deregulated in PSC patients compared to the PBC group. The Gene Ontology and pathway analyses highlighted that several proteins (e.g., small integral membrane protein 22, cofilin-1, macrophage-capping protein, plastin-2, and biliverdin reductase A) were linked to innate immune responses and actin cytoskeleton remodeling, which is a critical event in liver fibrosis and cancer progression. These findings provide new foundations for a deeper understanding of the pathophysiology of PSC and demonstrate that saliva is a suitable biological sample for obtaining proteomic fingerprints useful in the search for biomarkers capable of discriminating between the two cholestatic diseases.

Molecular Mechanisms of Fibrosis in Cholestatic Liver Diseases and Regenerative Medicine-Based Therapies

The aim of this review is to explore the potential of new regenerative medicine approaches in the treatment of cholestatic liver fibrosis. Cholestatic liver diseases, such as primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and biliary atresia (BA), due to the accumulation of bile, often progress to liver fibrosis, cirrhosis, and liver failure. When the disease becomes severe enough to require liver transplantation. Deeply understanding the disease's progression and fibrosis formation is crucial for better diagnosis and treatment. Current liver fibrosis treatments mainly target the root causes and no direct treatment method in fibrosis itself. Recent advances in regenerative medicine offer a potential approach that may help find the ways to target fibrosis directly, offering hope for improved outcomes. We also summarize, analyze, and discuss the current state and benefits of regenerative medicine therapies such as mesenchymal stem cell (MSC) therapy, induced pluripotent stem cells (iPSCs), and organoid technology, which may help the treatment of cholestatic liver diseases. Focusing on the latest research may reveal new targets and enhance therapeutic efficacy, potentially leading to more effective management and even curative strategies for cholestatic liver diseases.

Primary sclerosing cholangitis: Is qualitative and quantitative 3 T MR imaging useful for the evaluation of disease severity?

Purpose

To analyze the role of qualitative and quantitative 3 T MR imaging assessment as a non-invasive method for the evaluation of disease severity in patients with primary sclerosing cholangitis (PSC).

Methods

A series of 26 patients, with histological diagnosis of PSC undergoing 3 T MRI and hepatological evaluation, was retrospectively enrolled. All MR examinations included diffusion-weighted imaging (DWI), T2-weighted (T2w) and T1-weighted (T1w) sequences, before and after administration of Gd-EOB-DTPA with the acquisition of both dynamic and hepato-biliary phase (HBP). Qualitative analysis was performed by assessment of liver parenchyma and biliary tract changes, also including biliary excretion of gadoxetic acid on HBP. Quantitative evaluation was conducted on liver parenchyma by measurement of apparent diffusion coefficient (ADC) and relative enhancement (RE) on 3-minute delayed phase and on HBP. Results of blood tests (ALT, ALP, GGT, total and direct bilirubin, albumin, and platelets) and transient elastography-derived liver stiffness measurements (TE-LSM) were collected and correlated with qualitative and quantitative MRI findings.

Results

Among qualitative and quantitative findings, fibrosis visual assessment and RE had the best performance in estimating disease severity, showing a statistically significant correlation with both biomarkers of cholestasis and TE-LSM. Statistical analysis also revealed a significant correlation of gadoxetic acid biliary excretion with ALT and direct bilirubin, as well as of ADC with total bilirubin.

Conclusion

Qualitative and quantitative 3 T MR evaluation is a promising non-invasive method for the assessment of disease severity in patients with PSC.

Hepatic immune regulation and sex disparities

Chronic liver disease is a major cause of morbidity and mortality worldwide. Epidemiology, clinical phenotype and response to therapies for gastrointestinal and liver diseases are commonly different between women and men due to sex-specific hormonal, genetic and immune-related factors. The hepatic immune system has unique regulatory functions that promote the induction of intrahepatic tolerance, which is key for maintaining liver health and homeostasis. In liver diseases, hepatic immune alterations are increasingly recognized as a main cofactor responsible for the development and progression of chronic liver injury and fibrosis. In this Review, we discuss the basic mechanisms of sex disparity in hepatic immune regulation and how these mechanisms influence and modify the development of autoimmune liver diseases, genetic liver diseases, portal hypertension and inflammation in chronic liver disease. Alterations in gut microbiota and their crosstalk with the hepatic immune system might affect the progression of liver disease in a sex-specific manner, creating potential opportunities for novel diagnostic and therapeutic approaches to be evaluated in clinical trials. Finally, we identify and propose areas for future basic, translational and clinical research that will advance our understanding of sex disparities in hepatic immunity and liver disease.

Regulatory T cells-related gene in primary sclerosing cholangitis: evidence from Mendelian randomization and transcriptome data

The present study utilized large-scale genome-wide association studies (GWAS) summary data (731 immune cell subtypes and three primary sclerosing cholangitis (PSC) GWAS datasets), meta-analysis, and two PSC transcriptome data to elucidate the pivotal role of Tregs proportion imbalance in the occurrence of PSC. Then, we employed weighted gene co-expression network analysis (WGCNA), differential analysis, and 107 combinations of 12 machine-learning algorithms to construct and validate an artificial intelligence-derived diagnostic model (Tregs classifier) according to the average area under curve (AUC) (0.959) in two cohorts. Quantitative real-time polymerase chain reaction (qRT-PCR) verified that compared to control, Akap10, Basp1, Dennd3, Plxnc1, and Tmco3 were significantly up-regulated in the PSC mice model yet the expression level of Klf13, and Scap was significantly lower. Furthermore, immune cell infiltration and functional enrichment analysis revealed significant associations of the hub Tregs-related gene with M2 macrophage, neutrophils, megakaryocyte-erythroid progenitor (MEP), natural killer T cell (NKT), and enrichment scores of the autophagic cell death, complement and coagulation cascades, metabolic disturbance, Fc gamma R-mediated phagocytosis, mitochondrial dysfunction, potentially mediating PSC onset. XGBoost algorithm and SHapley Additive exPlanations (SHAP) identified AKAP10 and KLF13 as optimal genes, which may be an important target for PSC.

Hepatic bile acid accretion correlates with cholestatic liver injury and therapeutic response in Cyp2c70 knockout mice with a humanized bile acid composition

Cyp2c70 knockout (KO) mice lack the liver enzyme responsible for synthesis of 6-hydroxylated muricholate bile acid species and possess a more hydrophobic human-like bile acid composition. Cyp2c70 KO mice develop cholestatic liver injury that can be prevented by the administration of an ileal bile acid transporter (IBAT) inhibitor. In this study, we investigated the potential of an ileal bile acid transporter (IBAT) inhibitor (SC-435) and steroidal farnesoid X receptor (FXR) agonist (cilofexor) to modulate established hepatobiliary injury and the consequent relationship of intrahepatic bile acid content and hydrophobicity to the cholestatic liver injury phenotype. Oral administration of SC-435, cilofexor, or combined treatment for 2 wk markedly reduced serum markers of liver injury and improved histological and gene expression markers of fibrosis, liver inflammation, and ductular reaction in male and female Cyp2c70 KO mice, with the greatest benefit in the combination treatment group. The IBAT inhibitor and FXR agonist significantly reduced intrahepatic bile acid content but not hepatic bile acid pool hydrophobicity, and markers of liver injury were strongly correlated with intrahepatic total bile acid and taurochenodeoxycholic acid accretion. Biomarkers of liver injury increased linearly with similar hepatic thresholds for pathological accretion of hydrophobic bile acids in male and female Cyp2c70 KO mice. These findings further support targeting intrahepatic bile acid retention as a component of treatments for cholestatic liver disease.NEW & NOTEWORTHY Bile acids are implicated as a common contributor to the pathogenesis and progression of cholestatic liver disease. Using a mouse model with a humanized bile acid composition, we demonstrated that mono and combination therapy using an IBAT inhibitor and FXR nonsteroidal agonist were effective at reducing hepatic bile acid accretion and reversing liver injury, without reducing hepatic bile acid hydrophobicity. The findings support the concept of a therapeutically tractable threshold for bile acid-induced liver injury.

The prevalence and disease course of autoimmune liver diseases in Greenland

Autoimmune liver diseases are rare serious diseases causing chronic inflammation and fibrosis in the liver parenchyma and bile ducts. Yet, the prevalence and burden of autoimmune liver diseases are largely unexplored in Arctic native populations. We investigated the prevalence and management of autoimmune liver diseases in Greenland using nationwide cross-sectional register data and subsequent medical chart reviews validating diagnoses and extracting liver histology examinations and medical treatments. The overall prevalence of autoimmune liver diseases in Greenland was 24.6 per 100,000 (95% CI: 14.7-41.3). This was based on 7 patients with autoimmune hepatitis (AIH) (12.3 per 100,000), 3 patients with primary biliary cholangitis (PBC) (5.3 per 100,000), 4 patients with AIH/PBC overlap disease (7.0 per 100,000), and no patients with primary sclerosing cholangitis. All diagnoses were confirmed by liver histology examinations. Medical treatments adhered to internal recommendations and induced complete remission in most patients with AIH, and complete or partial remission in 1 patient with PBC and 3 patients with AIH/PBC overlap disease. One patient had established cirrhosis at the time of diagnosis, while 2 patients progressed to cirrhosis. In conclusion, the prevalence of autoimmune liver diseases was lower in Greenland than in Scandinavia and among Alaska Inuit.

Causal effect of primary sclerosing cholangitis on diffuse large B-cell lymphoma: A two-sample Mendelian randomized study

The connection between Primary sclerosing cholangitis (PSC) and lymphoma remains uncertain. To address this, Mendelian randomization (MR) was utilized to investigate the potential causal links between PSC and lymphoma. A 2-sample MR analysis was conducted utilizing summary-level data obtained from genome-wide association study datasets. Four complementary MR methods were performed, including inverse-variance weighting (IVW), MR-Egger, weighted median, and MR-robust adjusted profile score (MR-RAPS). Several sensitivity analyses were also employed to further validate the results. The results of IVW estimates showed that there was a potential causal association between PSC and diffuse large B-cell lymphoma (DLBCL) risk (OR = 1.138, 95% CI = 1.052-1.230, P = .001). No causal association was observed between PSC and other lymphoma subtypes. No horizontal and directional pleiotropy was observed in the MR studies. This study represents the inaugural utilization of MR analysis to investigate the causal associations between PSC and DLBCL. Further investigation is warranted to elucidate the underlying mechanism of this causal relationship.

Ursodeoxycholic acid and severe COVID-19 outcomes in a cohort study using the OpenSAFELY platform

BACKGROUND

Biological evidence suggests ursodeoxycholic acid (UDCA)-a common treatment of cholestatic liver disease-may prevent severe COVID-19 outcomes. We aimed to compare the hazard of COVID-19 hospitalisation or death between UDCA users versus non-users in a population with primary biliary cholangitis (PBC) or primary sclerosing cholangitis (PSC).

METHODS

With the approval of NHS England, we conducted a population-based cohort study using primary care records between 1 March 2020 and 31 December 2022, linked to death registration data and hospital records through the OpenSAFELY-TPP platform. Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between time-varying UDCA exposure and COVID-19 related hospitalisation or death, stratified by geographical region and considering models unadjusted and fully adjusted for pre-specified confounders.

RESULTS

We identify 11,305 eligible individuals, 640 were hospitalised or died with COVID-19 during follow-up, 400 (63%) events among UDCA users. After confounder adjustment, UDCA is associated with a 21% relative reduction in the hazard of COVID-19 hospitalisation or death (HR 0.79, 95% CI 0.67-0.93), consistent with an absolute risk reduction of 1.35% (95% CI 1.07%-1.69%).

CONCLUSIONS

We found evidence that UDCA is associated with a lower hazard of COVID-19 related hospitalisation and death, support calls for clinical trials investigating UDCA as a preventative measure for severe COVID-19 outcomes.

Racial Disparities in Inpatient Hospital Outcomes of Primary Sclerosing Cholangitis in United States: Nationwide Analysis

Background: Primary sclerosing cholangitis (PSC) is an idiopathic cholestatic liver disease that may lead to biliary strictures and destruction. It is associated with p-ANCA positivity and inflammatory bowel disease, typically ulcerative colitis. The aim of this study is to investigate the trends of inpatient healthcare utilization and mortality from 2008 to 2017 in the United States. Methods: The Nationwide Inpatient Sample (NIS) was examined to identify adult patients diagnosed with PSC between 2008 and 2017. Data on patient demographics, resource utilization, mortality, and PSC-related complications were collected. STATA version 16.0 was employed to perform forward stepwise multivariate regression analysis, generating adjusted odds ratios for both primary and secondary outcomes. Primary outcomes included the inpatient mortality rate and healthcare resource utilization (length of stay, total charges, and trends over the study period). Secondary outcomes focused on trends in associated comorbidities and malignancies in patients with PSC. Results: The average total charge increased by 32.2% ± 2.12 from USD 61,873 ± 2567 in 2008 to USD 91,262 ± 2961 in 2017. Concurrently, the average length of stay declined from 8.07 ± 0.18 days in 2008 to 7.27 ± 0.13 days in 2017. The APR-DRG severity of illness and risk of death significantly increased (major or extreme) during the study period (2008 to 2017), with severity rising from 73.6% to 82.7% (coefficient: 0.21, 95% CI: 0.13-0.28) and risk of death from 45.3% to 60.9% (coefficient: 0.15, 95% CI: 0.08-0.23). The proportion of patients with HCC increased from 1.3% to 7.9% (coefficient: 2.13, 95% CI: 1.9-2.8). Conversely, the percentage of patients with cholangiocarcinoma (CCA) decreased from 5.1% to 2.8% (coefficient: -0.36, 95% CI: -0.25 to -0.46). Conclusions: There was rising mortality and healthcare resource utilization among patients with PSC from the years 2008 to 2017. These trends were paralleled by increasing rates of decompensated cirrhosis, HCC, and liver transplants. However, the incidence of CCA decreased during this time period. African American patients with PSC had worse inpatient mortality outcomes and healthcare utilization as compared to white patients. Further studies are warranted to investigate a possible causal link amongst these trends.

Oral N-acetylcysteine ameliorates liver fibrosis and enhances regenerative responses in Mdr2 knockout mice

Cholangiopathies are poorly understood disorders with no effective therapy. The extrahepatic biliary tree phenotype is less studied compared to the intrahepatic biliary injury in both human disease and Mdr2-/- mice, the established cholestatic mouse model. This study aimed to characterize the extra hepatic biliary tree of Mdr2-/- mice at various ages and to determine if injury can be repaired with the antioxidant and glutathione precursor N-acetyl-L-Cysteine treatment (NAC). We characterized extra hepatic bile ducts (EHBD)s at various ages from 2 to 40 weeks old FVB/N and Mdr2-/- mice. We examined the therapeutic potential of local NAC ex vivo using EHBD explants at early and late stages of injury; and systematic therapy by in vivo oral administration for 3 weeks. EHBD and liver sections were assessed by histology and immunofluorescent stains. Serum liver enzyme activities were analyzed, and liver spatial protein expression analysis was performed. Mdr2-/- mice developed progressive EHBD injury, similar to extrahepatic PSC. NAC treatment of ex vivo EHBD explants led to improved duct morphology. In vivo, oral administration of NAC improved liver fibrosis, and decreased liver enzyme activities. Spatial protein analysis revealed cell-type specific differential response to NAC, collectively indicating a transition from pro-apoptotic into proliferative state. NAC treatment should be further investigated as a potential therapeutic option for human cholangiopathies.

Cultured Bacteria Isolated from Primary Sclerosing Cholangitis Patient Bile Induce Inflammation and Cell Death

Background

Primary sclerosing cholangitis (PSC) is a chronic liver disease characterized by inflammation and progressive fibrosis of the biliary tree. The pathogenesis of PSC remains poorly understood, and there are no effective therapeutic options. Previous studies have observed associations between changes in the colonic and biliary microbiome and PSC. We aimed to determine whether bacterial isolates cultured from PSC patient bile induced disease-associated phenotypes in cells.

Methods

Bile was collected from PSC patients (n=10) by endoscopic retrograde cholangiography and from non-PSC controls (n=3) undergoing cholecystectomies. Biliary bacteria were cultured anaerobically, and 50 colonies per sample were identified by 16S rRNA sequencing. The effects of supernatants from seven PSC-associated bacterial strains on cellular phenotypes were characterized using human colonic (Caco-2), hepatic (HepG2), and biliary (EGI-1) cells.

Results

No bacteria were isolated from non-PSC controls, while bacteria were cultured from most PSC patients. The PSC bile microbiomes exhibited reduced diversity compared to the gut or oral cavity, with one or two bacterial strains predominating. Overall, PSC-associated bacteria produced factors that were cytotoxic to hepatic and biliary cells. Enterococcus faecalis , and to a lesser extent Veillonella parvula , induced epithelial permeability, while Escherichia coli, Fusobacterium necrophorum , and Klebsiella pneumoniae induced inflammatory cytokines in biliary cells.

Conclusions

Our data suggest that bacteria cultured from PSC bile induce cellular changes that may contribute to PSC disease pathogenesis. Enterococcus may promote intestinal permeability, facilitating bacterial migration to the biliary tree. Once there, Escherichia, Fusobacterium and Klebsiella , may cause inflammation and damage in biliary and liver cells.