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ABSTRACT Background Primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC) are rare, chronic cholestatic liver diseases with heterogeneous progression and limited biomarkers of disease biology. Epigenetic age acceleration has been demonstrated in PSC and PBC, suggesting accelerated biological aging. DNA methylation–derived telomere length (DNAmTL) reflects replicative aging and cellular turnover, but its role in PSC and PBC remains unclear. We aimed to evaluate DNAmTL in PSC and PBC and its association with disease severity. Methods We analysed and compared DNAmTL and age‐adjusted DNAmTL among patients with PSC ( n = 474) versus PSC controls ( n = 484) and patients with PBC ( n = 291) versus PBC controls ( n = 291). Associations with clinical outcomes were assessed using nonparametric tests and multivariable logistic regression models. Correlations with primary sclerosing cholangitis Risk Estimate Tool (PREsTO) score and epigenetic age acceleration (AgeAccelGrim) were evaluated using linear regression. Results Patients with PSC demonstrated significantly shorter age‐adjusted DNAmTL compared with controls (median −0.036 vs. 0.016, p < 0.001). Patients with PBC also exhibited reduced DNAmTL relative to controls (median 6.814 vs. 6.885, p < 0.001). Within PSC, shorter DNAmTL was associated with cirrhosis (OR 0.21, 95% CI 0.06–0.69, p = 0.013) and advanced disease (OR 0.20, 95% CI 0.06–0.67, p = 0.009). Shorter DNAmTL was also observed in hepatic decompensation and hepatobiliary malignancy, including cholangiocarcinoma. DNAmTL inversely correlated with PReSTO score ( p < 0.001). DNAmTL was strongly inversely correlated with AgeAccelGrim in both PSC and PBC ( p < 0.001). Conclusion Cholestatic liver diseases are associated with shortened DNAmTL, which independently correlates with disease severity in PSC. Together with epigenetic age acceleration, these findings support a model of accelerated biological aging in PSC and PBC characterized by converging signatures of accelerated biological aging that may contribute to progressive biliary injury and fibrosis.

Introduction: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease without approved medical therapies. We examined the efficacy and safety of oral vancomycin (OV) in those with PSC. Methods: In this phase 3, 18-month, double-blind, placebo-controlled trial, we randomly assigned adults with PSC and a serum alkaline phosphatase (SAP) greater than 1.5 times the upper limit of normal to placebo or oral vancomycin (OV) with dosages ranging from 125-375 mg four times daily pending biochemical response. The primary endpoint was normalization of SAP. Results: Of the 82 patients who underwent randomization, 73 individuals had at least one outcome assessment. Individuals who withdrew early were less likely to rate their baseline health as excellent or very good (23.4% vs 54.5%, p<0.01) despite having similar PSC prognostic features to those who completed the study. SAP normalization rates were similar (5% placebo, 6.7% OV, p=1.00) after 18 months. Those who received OV had greater reduction in SAP (+1.2% placebo, -21.9% OV, p=0.03). There were no differences in the changes in either the Mayo PSC risk score (-0.1 placebo, -0.1 OV, p=0.88) or liver stiffness values (+0.1 kPa placebo, -4.0 kPa OV, p=0.15). Discoloration of the teeth and tongue was the most common side effect of OV (17.5%). Conclusions: OV was not associated with clinically significant reductions in markers of PSC disease severity. Impairments in quality of life may influence patient retention in clinical trials.

Cholangiocytes are specialized epithelial cells that line the intrahepatic and extrahepatic biliary tree and play a critical role in bile modification, liver homeostasis, and response to injury. Cholangiocytes exhibit notable heterogeneity and plasticity, and their dysfunction is central to a spectrum of diseases targeting the bile ducts, collectively called cholangiopathies. These disorders include genetic, infectious, immune-mediated, and malignant diseases, with primary sclerosing cholangitis (PSC) representing one of the most complex and enigmatic of these disorders. PSC is a progressive, fibro-inflammatory disease of the bile ducts that is closely linked to inflammatory bowel disease, carries a heightened risk of cancer, and lacks any approved therapies. This review explores the biology of cholangiocytes, including their development, functional plasticity, and roles in secretion, absorption, and cellular signaling. We provide a detailed examination of cholangiopathies, particularly PSC, a complex cholangiopathy characterized by a paradoxical state of cholangiocyte senescence and hyperproliferation. We describe how immune cell dysfunction, the gut microbiome, genetic predispositions, and environmental factors converge to mediate PSC pathogenesis. We revisit the foundational technologies that empowered early discoveries and shaped the field as we know it today. We also explore how newer techniques such as organoid cultures, single-cell transcriptomics, epigenomics, and spatialomics have transformed our modern understanding of biliary pathophysiology. Finally, we provide an overview of existing rodent models of cholangiopathies and discuss their relevance to human disease. PSC remains therapeutically unaddressed, and thus ongoing multidisciplinary efforts are essential to developing targeted interventions. This review serves as a comprehensive resource for researchers and clinicians navigating the rapidly evolving landscape of cholangiocyte-centered liver disease research.

ABSTRACT Background and Aims Cellular senescence is a hallmark of several liver diseases, including primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC). Senescent cholangiocytes exhibit a senescence‐associated secretory phenotype (SASP), characterized by profibroinflammatory mediator release. Current cost‐effective biomarkers predicting disease progression, particularly for PSC, are limited and often lack mechanistic relevance. We sought to define a plasma biomarker signature for PSC and PBC. Methods Plasma from early‐ and late‐stage PSC and PBC, alcoholic liver disease (ALD), inflammatory bowel disease (IBD) patients, and healthy controls was analyzed. Seventy‐one analytes were quantified using Luminex Multiplex Immunoassay or enzyme‐linked immunosorbent assay (ELISA). Principal component analysis (PCA) identified key patterns. Findings from the PSC cohort were then applied to additional cohorts. Results Second principal component (PC2) (17 analytes, 17.1% variability) best separated PSC from controls. ANOVA showed significant differences in PC2 between early PSC vs. controls ( p = 0.0001), late PSC vs. controls ( p < 0.0001), and early vs. late PSC ( p < 0.0001). PC2 analytes also distinguished early PBC vs. controls ( p < 0.0332), late PBC ( p < 0.0001), and ALD ( p < 0.0001), and early vs. late PBC ( p < 0.0001), but not IBD vs. controls ( p = 0.119). Logistic regression using PC2 demonstrated strong discrimination of early‐ and late‐stage PSC (AUC = 0.86) and control vs. early‐stage PSC (AUC = 0.83). Conclusion This is the first study to define a plasma SASP biomarker signature associated with cholestatic liver disease. These analytes track disease stage and represent both mechanistic indicators and potential clinical trial endpoints.

Background and Aims: Cholangiocarcinoma (CCA) is a rare but aggressive malignancy with poorly understood genetic susceptibility. To date, genome-wide association studies (GWAS) investigating germline variants associated with CCA risk remain limited. We aimed to identify genetic risk loci for CCA and its clinical subtypes through comprehensive GWAS and post-GWAS analyses. Approach and Results: We conducted a GWAS of 2366 CCA cases and 11,750 controls of European ancestry. Genome-wide significant loci ( p <5×10 −8 ) were identified and further examined through fine-mapping, functional annotation, and HLA imputation. Subgroup analyses were conducted by CCA subtypes and primary sclerosing cholangitis (PSC) status. Cross-trait linkage disequilibrium score regression and Mendelian randomization were employed to investigate the shared genetic architecture and potential causal relationships with a diverse range of traits. We identified 1 new genome-wide significant variant, rs535777 (OR=1.44), near HLA-DRB1/DQA1 associated with CCA, and 2 variants associated with extrahepatic CCA: rs116224263 (OR=0.17) in LINC02506 at 4p15.1 and rs6914950 (OR=1.63) near HLA-DRB1/DQB1 . Stratified analyses revealed rs2395184 (OR=3.51) near HLA-DRA/DRB5 associated with PSC-related CCA, and rs142674434 (OR=2.98) in THSD7A at 7p21.3 associated with non-PSC-related CCA. HLA imputation uncovered new amino acid residues associated with disease risk. Cross-trait analyses identified shared genetic signals between CCA and anthropometric, lipidemic, lifestyle, and medical traits. Mendelian randomization supported putative causal associations for 12 traits with CCA or its subtypes. Conclusions: Our large-scale GWAS highlights new genetic variants and HLA-linked mechanisms underlying CCA susceptibility. Integrating multi-step post-GWAS approaches enhances understanding of CCA pathogenesis and may facilitate the development of risk biomarkers for early detection and precision prevention strategies.

Cholangiocyte pathophysiological activation was examined in a model of murine cholestasis. CX3CR1 + macrophages are recruited to the periportal region, likely mediated by cholangiocyte expression of CX3CL1. Cholangiocyte transcriptomics from cholestatic mice display activation of a “pathogen-induced cytokine storm” pathway, and exhibit activation of the transcription factor NF-Y. In human cholangiocytes, NF-Y promotes expression of the profibrogenic ligand TGFβ1. These observations provide insights into the cholestatic cholangiocyte pathobiology contributing to periductal inflammation and fibrosis.

Abstract Cholangiocytes are epithelial cells that line the intra‐ and extrahepatic ducts of the biliary tree. The main physiologic function of cholangiocytes is modification of hepatocyte‐derived bile, an intricate process regulated by hormones, peptides, nucleotides, neurotransmitters, and other molecules through intracellular signaling pathways and cascades. The mechanisms and regulation of bile modification are reviewed herein. © 2013 American Physiological Society. Compr Physiol 3:541‐565, 2013.

Background and Aims: Among those with primary sclerosing cholangitis (PSC), perihilar cholangiocarcinoma (pCCA) is often diagnosed at a late stage and is a leading source of mortality. Detection of pCCA in PSC when curative action can be taken is challenging. Our aim was to create a deep learning model that analyzed MRI to detect early-stage pCCA and compare its diagnostic performance with expert radiologists. Approach and Results: We conducted a multicenter, international, retrospective cohort study involving adults with large duct PSC who underwent contrast-enhanced MRI. Senior abdominal radiologists reviewed the images. All patients with pCCA had early-stage cancer and were registered for liver transplantation. We trained a 3D DenseNet-121 model, a form of deep learning, using MRI images and assessed its performance in a separate test cohort. The study included 398 patients (training cohort n=150; test cohort n=248). pCCA was present in 230 individuals (training cohort n=64; test cohort n=166). In the test cohort, the respective performances of the model compared to the radiologists were: sensitivity 87.9% versus 50.0%, p <0.001; specificity 84.1% versus 100.0%, p <0.001; area under receiving operating curve 86.0% versus 75.0%, p <0.001. Even when a mass was absent, the model had a higher sensitivity for pCCA than radiologists (91.6% vs. 50.6%, p <0.001) and maintained good specificity (84.1%). Conclusions: The 3D DenseNet-121 MRI model effectively detects early-stage pCCA in PSC patients. Compared to expert radiologists, the model missed fewer cases of cancer.