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Progress in development of prognostic and therapeutic options for the rare cholestatic liver diseases, primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), is hampered by limited knowledge of their pathogeneses. In particular, the potential role of hepatotoxic and/or metabolism‐altering environmental chemicals in the pathogenesis of these diseases remains relatively unstudied. Moreover, the extent to which metabolic pathways are altered due to ongoing cholestasis and subsequent liver damage or possibly influenced by hepatotoxic chemicals is poorly understood. In this study, we applied a comprehensive exposomics‐metabolomics approach to uncover potential pathogenic contributors to PSC and PBC. We used untargeted high‐resolution mass spectrometry to characterize a wide range of exogenous chemicals and endogenous metabolites in plasma and tested them for association with disease. Exposome‐wide association studies (EWAS) identified environmental chemicals, including pesticides, additives and persistent pollutants, that were associated with PSC and/or PBC, suggesting potential roles for these compounds in disease pathogenesis. Metabolome‐wide association studies (MWAS) found disease‐associated alterations to amino acid, eicosanoid, lipid, co‐factor, nucleotide, mitochondrial and microbial metabolic pathways, many of which were shared between PSC and PBC. Notably, this analysis implicates a potential role of the 5‐lipoxygenase pathway in the pathogenesis of these diseases. Finally, EWAS × MWAS network analysis uncovered linkages between environmental agents and disrupted metabolic pathways that provide insight into potential mechanisms for PSC and PBC. Conclusion: This study establishes combined exposomics‐metabolomics as a generalizable approach to identify potentially pathogenic environmental agents and enumerate metabolic alterations that may impact PSC and PBC, providing a foundation for diagnostic and therapeutic strategies. [ABSTRACT FROM AUTHOR]

A study was conducted to investigate the genetic basis of primary biliary cirrhosis and the loci associated with it. Results indicated a significant connection between the cirrhosis and the HLA, IL12A, and IL12RB2 loci and the possibility that modulation of signaling by interleukin-12 and its receptor could prove beneficial in the treatment of this ailment.

Primary sclerosing cholangitis (PSC) is a chronic fibroinflammatory disease of the biliary tract characterized by cellular senescence and periportal fibrogenesis. Specific disease features that are cell intrinsic and either genetically or epigenetically mediated remain unclear due in part to a lack of appropriate, patient‐specific, in vitro models. Recently, our group developed systems to create induced pluripotent stem cell (iPSC)‐derived cholangiocytes (iDCs) and biliary epithelial organoids (cholangioids). We use these models to investigate whether PSC cholangiocytes are intrinsically predisposed to cellular senescence. Skin fibroblasts from healthy controls and subjects with PSC were reprogrammed to pluripotency, differentiated to cholangiocytes, and subsequently grown in three‐dimensional matrigel‐based culture to induce formation of cholangioids. RNA sequencing (RNA‐seq) on iDCs showed significant differences in gene expression patterns, including enrichment of pathways associated with cell cycle, senescence, and hepatic fibrosis, that correlate with PSC. These pathways also overlapped with RNA‐seq analysis on isolated cholangiocytes from subjects with PSC. Exome sequencing on the subjects with PSC revealed genetic variants of unknown significance in the genes identified in these pathways. Three‐dimensional culture revealed smaller size, lack of a central lumen, and increased cellular senescence in PSC‐derived cholangioids. Congruent with this, PSC‐derived iDCs showed increased secretion of the extracellular matrix molecule fibronectin as well as the inflammatory cytokines interleukin‐6, and chemokine (C‐C motif) ligand 2. Conditioned media (CM) from PSC‐derived iDCs more potently activated hepatic stellate cells compared to control CM. Conclusion: We demonstrated efficient generation of iDCs and cholangioids from patients with PSC that show disease‐specific features. PSC cholangiocytes are intrinsically predisposed to cellular senescence. These features are unmasked following biliary differentiation of pluripotent stem cells and have functional consequences in epithelial organoids. [ABSTRACT FROM AUTHOR]

The United Kingdom‐Primary Biliary Cholangitis (UK‐PBC) risk scores are a set of prognostic models that estimate the risk of end‐stage liver disease in patients with PBC at 5‐, 10‐ and 15‐year intervals. They have not been externally validated outside the United Kingdom. In this retrospective, external validation study, data were abstracted from outpatient charts and discrimination and calibration of the UK‐PBC risk scores were assessed. A total of 464 patients with PBC treated with ursodeoxycholic acid were included. The median diagnosis age was 52.4 years, and 88% were female patients. The cumulative incidence of events was 6%, 9%, and 15% at 5, 10, and 15 years, respectively. Concordance (c‐statistic) was 0.88, 0.85, and 0.84 using the 5‐, 10‐ and 15‐year risk scores, respectively, which was slightly lower than values observed in the United Kingdom validation cohort. Using the 5‐year risk score, more events were observed than predicted (25 versus 16.8; P = 0.046); using the 10‐year risk score, there was no difference between the observed and predicted number of events (35 versus 44.9; P = 0.14); conversely, using the 15‐year risk score, fewer events were observed than predicted (46 versus 67.5; P = 0.009). Limiting evaluation by the 15‐year UK‐PBC risk score to those with >10 years of follow‐up demonstrated no difference between observed and predicted events. Using the 5‐year risk score, patients within the highest quartile had statistically significant worse event‐free survival compared to the rest of the cohort: 82% versus 98% at 5 years, 73% versus 97% at 10 years, and 58% versus 93% at 15 years. Conclusion: In patients assessed at a North American tertiary medical center, the UK‐PBC risk score had excellent discrimination and was reasonably calibrated both in the short and long term. (Hepatology Communications 2018;2:676‐682) [ABSTRACT FROM AUTHOR]

Background & Aims Primary biliary cirrhosis ( PBC) is characterized by chronic cholestasis and disease-specific antimitochondrial antibodies ( AMA). A high prevalence of AMAs in first-degree relatives ( FDRs) of PBC probands has been reported, although the natural history of such patients has not been described. We aimed to assess the risk of developing PBC in AMA+ FDRs of patients with PBC. Methods First-degree relatives recruited to the Mayo Clinic PBC Genetic Epidemiology Registry and Biorepository were followed for disease onset after recruitment. Development of PBC was ascertained via self-report during a telephone interview and/or via proband report on a questionnaire. Chi-squared test and t-test were used to assess the differences between categorical and continuous variables respectively. A mixed-effects model was used to assess the change in biochemical profiles over time. Results Forty AMA+ and 423 AMA− subjects were included and followed for a median of 8.9 and 8.4 years respectively. Overall, 3% ( n = 15) of FDRs were diagnosed with PBC, and AMA+ FDRs had a higher risk than AMA− FDRs (24% vs. 0.7%, P < 0.01). However, among undiagnosed FDRs, only 4% of AMA+ ( n = 1) and 0.4% of AMA− ( n = 1) FDRs were diagnosed with PBC ( P = 0.17) during the follow-up period. None of the AMA+ FDRs with normal alkaline phosphatase at baseline developed PBC in follow-up. Conclusions Our results suggest a low risk of developing PBC over time in FDRs of patients with PBC, particularly those without biochemical evidence of cholestasis at baseline. These data are useful in counselling and reassuring relatives of their overall favourable prognosis. [ABSTRACT FROM AUTHOR]

Genetic risk factors for cholangiocarcinoma ( CCA) remain poorly understood. We assessed the effect of single-nucleotide polymorphisms ( SNPs) of genes modulating inflammation or carcinogenesis on CCA risk and survival. We conducted a case-control, candidate gene association study of 370 CCA patients and 740 age-, sex-, and residential area-matched healthy controls. Eighteen functional or putatively functional SNPs in nine genes were genotyped. The log-additive genotype effects of SNPs on CCA risk and survival were determined using logistic regression and the log-rank test, respectively. Initial analysis identified significant associations between SNP rs2143417 and rs689466 in cyclooxygenase 2 ( COX-2) and CCA risk, after adjusting for multiple comparisons (cutoff of P = 0.0028). However, these findings were not replicated in another independent cohort of 212 CCA cases and 424 matched controls. No significant association was found between any SNP and survival of CCA patients. Although COX-2 has been shown to contribute to cholangiocarcinogenesis, the COX-2 SNPs tested were not associated with risk of CCA. This study shows a lack of association between variants of genes related to inflammation and carcinogenesis and CCA risk and survival. Other factors than these genetic variants may play more important roles in CCA risk and survival. [ABSTRACT FROM AUTHOR]

Background & Aims: Small duct primary sclerosing cholangitis (PSC) is phenotypically a mild version of large duct PSC, but it is unknown whether these phenotypes share aetiology. We aimed to characterize their relationship by investigating genetic associations in the human leucocyte antigen (HLA) complex, which represent the strongest genetic risk factors in large duct PSC. Methods: Four classical HLA loci (HLA-A, HLA-B, HLA-C and HLA-DRB1) were genotyped in 87 small duct PSC patients, 485 large duct PSC patients and 1117 controls across three geographical regions. Results: HLA-DRB1*13:01 (OR = 2.0, 95% CI 1.2–3.4, P = 0.01) and HLA-B*08 (OR = 1.6, 95% CI 1.1–2.4, P = 0.02) were significantly associated with small duct PSC compared with healthy controls. Based on the observed frequency of HLA-B*08 in small duct PSC, the strongest risk factor in large duct PSC, an estimated 32% (95% CI 4–65%) of this population can be hypothesized to represent early stages or mild variants of large duct PSC. This subgroup may be constituted by small duct PSC patients with inflammatory bowel disease (IBD), which greatly resembled large duct PSC in its HLA association. In contrast, small duct PSC without IBD was only associated with HLA-DRB1*13:01(P = 0.03) and was otherwise distinctly dissimilar from large duct PSC. Conclusions: Small duct PSC with IBD resembles large duct PSC in its HLA association and may represent early stages or mild variants of large duct disease. Different HLA associations in small duct PSC without IBD could indicate that this subgroup is a different entity. HLA-DRB1*13:01 may represent a specific risk factor for inflammatory bile duct disease. [ABSTRACT FROM AUTHOR]