Epcam regulates intrahepatic bile duct reconstruction in zebrafish, providing a potential model for primary cholangitis model.

Epithelial cell adhesion molecules (EpCAMs) have been identified as surface markers of proliferating ductal cells, which are referred to as liver progenitor cells (LPCs), during liver regeneration and correspond to malignancies. These cells can differentiate into hepatocytes and biliary epithelial cells (BECs) in vitro. EpCAM-positive LPCs are involved in liver regeneration following severe liver injury; however, the in vivo function of EpCAMs in the regenerating liver remains unclear. In the present study, we used a zebrafish model of LPC-driven liver regeneration to elucidate the function of EpCAMs in the regenerating liver in vivo. Proliferating ductal cells were observed after severe hepatocyte loss in the zebrafish model. Analyses of the liver size as well as hepatocyte and BEC markers revealed successful conversion of LPCs to hepatocytes and BECs in epcam mutants. Notably, epcam mutants exhibited severe defects in intrahepatic duct maturation and bile acid secretion in regenerating hepatocytes, suggesting that epcam plays a critical role in intrahepatic duct reconstruction during LPC-driven liver regeneration. Our findings provide insights into human diseases involving non-parenchymal cells, such as primary biliary cholangitis, by highlighting the regulatory effect of epcam on intrahepatic duct reconstruction.

Regulatory T cells in inflamed liver are dysfunctional in murine primary biliary cholangitis.

Primary biliary cholangitis (PBC) is a chronic autoimmune disease characterized by immune-mediated destruction of intrahepatic small bile ducts. CD8 T cells play a critical role in biliary destruction. However, regulatory T cells (Tregs) have also been identified in the portal tracts of PBC patients. This study tested the hypothesis that hepatic Tregs in PBC were dysfunctional in suppressing immune responses in disease by using our human PBC-like autoimmune cholangitis (AIC) mouse model induced by 2-octynoic acid-conjugated ovalbumin (2-OA-OVA). Our results showed that female and male mice immunized with 2-OA-OVA developed AIC; however, female AIC mice had more severe liver inflammation and fibrosis than male AIC mice. Levels of functional effector CD8 T cells and their chemoattractants, CXCL9 and CXCL10, in the liver were markedly elevated in female AIC mice than in male AIC mice. These results reinforce that CD8 T cells are the primary effector cells in PBC. The number of hepatic Tregs in AIC mice was also higher than in saline-treated mice, but there was no difference between male and female AIC mice. The suppressive function of AIC Tregs was evident despite a discrepancy in the changes in their co-inhibitory receptors and inhibitory cytokines. However, the expansion of hepatic Tregs by low-dose IL-2 treatment did not reduce immune responses to AIC, which may be due to the dysfunction of Tregs in inhibiting T cells. In conclusion, the function of Tregs in the inflamed liver of PBC was insufficient, and low-dose IL-2 treatment could not restore their function to suppress pathological immune responses. Transferring normal Tregs or directly targeting effector CD8 T cells may be beneficial for treating PBC.

A new method to estimate the histological stage of primary biliary cholangitis.

OBJECTIVE: To analyze the diagnostic efficacy of the periportal hypoechoic band (PHB) in the histological stage of patients with primary biliary cholangitis (PBC). METHODS: We prospectively included 77 cases of PBC pathologically or clinically confirmed, and high-frequency ultrasound (HFUS) measurements of the PHB were performed in all included patients. Ludwig staging system of histopathology was used as the gold standard. RESULTS: The width of the PHB was positively correlated with histological staging (r = 0.844, p < 0.001). By area under the receiving operating characteristic curve (AUROC), the best cutoff value for PHB for advanced stage (≥ stage 3) was 2.4 mm (AUROC: 0.934; 95%CI: 0.841-0.981) and 0.93 for sensitivity, and 0.91 for specificity, the concordance rates of PHB vs. liver biopsy was 90.3%. The correct rate for early-stage PBC was 87.9% and for the progressive stage was 93.1%. After multi-factor regression analysis, the PHB (OR = 1.331, CI = 1.105-1.603, p = 0.003) and total bilirubin (OR = 1.156, CI = 1.041-1.285, p = 0.007) were independent influencing factors for progressive PBC. CONCLUSIONS: Measurement of the PHB to assess advanced PBC is a simple and effective method. This method may complement current methods for the histological staging assessment of patients with PBC. REGISTRATION: Clinical trial registration: ChiCTR 2000032053, 2020/04/19. CLINICAL RELEVANCE STATEMENT: The measurement of periportal hypoechoic band (PHB) provides a simple and easy assessment of the degree of disease progression in patients with PBC and provides an important clinical reference in predicting the histological staging of PBC from an ultrasound perspective. KEY POINTS: • The PHB is correlated with histological staging in the patient with PBC. • The area under the ROC curves of PHB for detecting advanced stage (≥ stage 3) were 0.934 and 0.93 for sensitivity, and 0.91 for specificity, the concordance rates of PHB vs. liver biopsy was 90.3%. The application of PHB can better assess the advanced PBC. • Measurement of the PHB to assess advanced PBC is a simple and effective method that can significantly reduce the need for liver biopsy.

IL-21, not IL-17A, exacerbates murine primary biliary cholangitis.

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease caused by intrahepatic bile duct injuries, resulting in fibrosis, cirrhosis, and eventually liver failure. T helper (Th) 17 cells are proposed to involve in the pathogenesis of PBC. However, how and which Th17 cell-derived cytokines affect PBC remains unclear. In this study, we investigated the effects of Th17 effector cytokines, including interleukin (IL)-17A, IL-17F, and IL-21 in PBC using a xenobiotic-induced mouse model of autoimmune cholangitis (inducible chemical xenobiotic models of PBC) treated with cytokine-expressing adeno-associated virus. Our results showed that administration of IL-17A, the well-known main cytokine produced by Th17 cells, did not augment liver inflammation or fibrosis. In contrast, we noted IL-17A-treated mice had lower hepatic Th1 cell numbers and higher hepatic CD11b+Ly6G+ polymorphonuclear myeloid-derived suppressor cell numbers. IL-17F did not alter liver inflammation or fibrosis. However, the administration of IL-21 exacerbated liver inflammatory responses and portal cell infiltration. IL-21 markedly increased the numbers of activated CD8+ T cells and liver tissue-resident memory CD8+ T cells. Moreover, IL-21 aggravates liver fibrosis in mice with autoimmune cholangitis. These results emphasized that not IL-17A but IL-21 in Th17 cell-derived cytokines affected the pathogenesis of PBC. IL-21 enhanced liver inflammation and progression to fibrosis by enhancing the numbers and effector activities of CD8+ T cells. Delineation of the effects of different Th17 effector cytokines in PBC offers clues for developing new therapeutic approaches.

Ultrasound imaging findings in primary biliary cholangitis.

BACKGROUND: Our study aimed to analyze the characteristics of ultrasound images corresponding to each histological stage of primary biliary cholangitis (PBC). METHODS: We prospectively analyzed 75 confirmed cases of PBC and used liver biopsy as the gold standard to determine the disease stage. RESULTS: The typical ultrasound images of patients with PBC were characterized by a thickening of the portal vein wall (PVW) and periportal hypoechoic band (PHB) width with increasing histological stages, and significant increases in the left hepatic lobe diameter (LHLD) in stage II (by 64.0%) and stage III (by 69.2%). PHB width (r = 0.857, p < 0.001), PVW thickness (r = 0.488, p < 0.001), and spleen area (r = 0.8774, p < 0.001) were positively correlated with the histological stage. Significant changes were noted in the liver surface, echo texture, and edge between different stages. The areas under the receiver operating characteristic curve of composite indicators were 0.965 for predicting progressive PBC(≥ stage 2), and 0.926 for predicting advanced PBC(≥ stage 3). CONCLUSIONS: The ultrasound imaging characteristics of patients with PBC varied according to the histological staging. LHLD, PVW thickness, and PHB width were significantly correlated with the histological stage. A combination of high- and low-frequency ultrasound imaging can provide relevant cues regarding the degree of PBC progression and important clinical reference values. The application of all the ultrasound image findings as the composite indicators can better predict progressive and advanced PBC, providing important clinical reference values.

Mechanism-based target therapy in primary biliary cholangitis: opportunities before liver cirrhosis?

Primary biliary cholangitis (PBC) is an immune-mediated liver disease characterized by cholestasis, biliary injuries, liver fibrosis, and chronic non-suppurative cholangitis. The pathogenesis of PBC is multifactorial and involves immune dysregulation, abnormal bile metabolism, and progressive fibrosis, ultimately leading to cirrhosis and liver failure. Ursodeoxycholic acid (UDCA) and obeticholic acid (OCA) are currently used as first- and second-line treatments, respectively. However, many patients do not respond adequately to UDCA, and the long-term effects of these drugs are limited. Recent research has advanced our understanding the mechanisms of pathogenesis in PBC and greatly facilitated development of novel drugs to target mechanistic checkpoints. Animal studies and clinical trials of pipeline drugs have yielded promising results in slowing disease progression. Targeting immune mediated pathogenesis and anti-inflammatory therapies are focused on the early stage, while anti-cholestatic and anti-fibrotic therapies are emphasized in the late stage of disease, which is characterized by fibrosis and cirrhosis development. Nonetheless, it is worth noting that currently, there exists a dearth of therapeutic options that can effectively impede the progression of the disease to its terminal stages. Hence, there is an urgent need for further research aimed at investigating the underlying pathophysiology mechanisms with potential therapeutic effects. This review highlights our current knowledge of the underlying immunological and cellular mechanisms of pathogenesis in PBC. Further, we also address current mechanism-based target therapies for PBC and potential therapeutic strategies to improve the efficacy of existing treatments.

Endoscopic Biliary Darinage (EBD) versus Percutaneous Transhepatic Biliary Drainage (PTBD) for biliary drainage in patients with Perihilar Cholangiocarcinoma (PCCA): A systematic review and meta-analysis.

Biliary drainage for Perihilar Cholangiocarcinoma (PCCA) can be performed either by endoscopic retrograde cholangiopancreatography or Percutaneous Transhepatic Biliary Drainage (PTBD). To date there is no consensus about which method is preferred. Taking that into account, the aim of this study is to compare Endoscopic Biliary Drainage (EBD) versus percutaneous transhepatic biliary drainage in patients with perihilar cholangiocarcinoma through a systematic review and metanalysis. A comprehensive search of multiple electronic databases was performed. Evaluated outcomes included technical success, clinical success, post drainage complications (cholangitis, pancreatitis, bleeding, and major complications), crossover, hospital length stay, and seeding metastases. Data extracted from the studies were used to calculate Mean Differences (MD). Seventeen studies were included, with a total of 2284 patients (EBD = 1239, PTBD = 1045). Considering resectable PCCA, the PTBD group demonstrated lower rates of crossover (RD = 0.29; 95% CI 0.07‒0.51; p = 0.009 I² = 90%), post-drainage complications (RD = 0.20; 95% CI 0.06‒0.33; p < 0.0001; I² = 78%), and post-drainage pancreatitis (RD = 0.10; 95% CI 0.05‒0.16; p < 0.0001; I² = 64%). The EBD group presented reduced length of hospital stay (RD = -2.89; 95% CI -3.35 ‒ -2,43; p < 0.00001; I² = 42%). Considering palliative PCCA, the PTBD group demonstrated a higher clinical success (RD = -0.19; 95% CI -0.27 ‒ -0.11; p < 0.00001; I² = 0%) and less post-drainage cholangitis (RD = 0.08; 95% CI 0.01‒0.15; p = 0.02; I² = 48%) when compared to the EBD group. There was no statistical difference between the groups regarding: technical success, post-drainage bleeding, major post-drainage complications, and seeding metastases.

Aberrant cytokeratin 7 expression by hepatocytes can predict the ductopenia grade in primary biliary cholangitis.

BACKGROUND: Aberrant cytokeratin 7 expression by hepatocytes (CK7+Hs) is the hallmark characteristic of cholestasis diseases, especially in ductopenia diseases such as primary biliary cholangitis (PBC). This study attempted to evaluate the differences and relationships between the clinical and histological features of aberrant cytokeratin 7 (CK7) expression by hepatocytes in PBC patients. METHODS: The clinicopathological data of patients diagnosed with PBC at the Second Hospital of Nanjing between January 2016 and September 2018 were analysed with SPSS 20.0. RESULTS: Eighty-nine PBC patients who underwent liver biopsy were enrolled in this study, and 15, 29 and 45 patients had aberrant CK7 expression by hepatocytes (CK7+Hs (2 +), CK7+Hs (1 +), and CK7-Hs, respectively). There were significant differences in TB, DB, ALP, TA, IgM, interface activity, and ductopenia grade between patients with CK7-Hs and CK7+Hs (2 +) (P < 0.05). The ductopenia grade was also significantly different between patients with CK7+Hs (2 +) and CK7+Hs (1 +) according to sex (P < 0.05). Upon merging the data of CK7+Hs (2 +) and CK7+Hs (1 +) into CK7+Hs, we found significant differences in AMA, AMA-M2, anti-gp210, TB, DB, ALP, TA, IgM, fibrosis, and ductopenia grade between CK7+Hs and CK7-Hs (P < 0.05). The odds ratios (ORs) (and 95% confidence intervals (CIs)) of CK7+Hs according to anti-gp210, ductopenia grade, and interface activity were 6.413 (95% CI 1.363-30.162), 4.145 (95% CI 1.898-9.052) and 3.247 (95% CI 1.556-6.775), respectively (P < 0.05). Spearman's rank correlation according to interface activity and ductopenia grade in patients with CK7+Hs (2 + , 1 + , 0) was r = 0.359 (P = 0.001) and r = 0.396 (P < 0.001), respectively. CONCLUSION: CK7+Hs serves as a cholestasis index of PBC and are associated with the ductopenia grade and interface activity. Aberrant cytokeratin 7 expression by hepatocytes can predict the ductopenia grade in primary biliary cholangitis.

Influencing factors of biliary fistula after radical resection of hilar cholangiocarcinoma: a prospect cohort.

BACKGROUND: Biliary fistula is a common but serious complication after radical resection of hilar cholangiocarcinoma. We aimed to evaluate the influencing factors of biliary fistula after radical resection, to provide insights to the clinical treatment of hilar cholangiocarcinoma. METHODS: Patients undergoing radical resection of hilar cholangiocarcinoma from January 1, 2015 to March 31, 2022 were selected. Patients' personnel characteristics and laboratory test results of patients with and without biliary fistula were collected and compared. Logistic regression analyses were conducted to evaluate the associated risk factors of biliary fistula. RESULTS: 160 patients undergoing radical resection of hilar cholangiocarcinoma were included, the incidence of postoperative biliary fistulas was 20.63%. There were significant differences in the age, preoperative cholangitis and number of biliary anastomosis between biliary fistula and no biliary fistula patients (all p < 0.05). There were significant differences in the gamma glutamyl transpeptidase (GGT) on the first day after surgery, Klebsiella pneumoniae between biliary fistula and no biliary fistula patients (all p < 0.05). Logistic regression analysis indicated that age ≥ 65 years (OR 2.035, 95%CI 1.131-3.007), preoperative cholangitis (OR 1.584, 95% CI 1.081-2.361), number of biliary anastomosis ≥ 2(OR 2.866, 95%CI 1.942-3.624), GGT on the first day after surgery ≥ 120 U/L (OR 1.823, 95%CI: 1.274-2.906), preoperative bile culture for Klebsiella pneumoniae (OR 3.181, 95%CI: 2.426-3.992) were the risk factors of postoperative biliary fistulas (all p < 0.05). CONCLUSIONS: There are many independent risk factors for postoperative biliary fistula in patients undergoing radical resection of hilar cholangiocarcinoma. Clinical medical workers should take early interventions and treatment measures for these high-risk patients to reduce the occurrence of postoperative biliary fistula.

A Case of Chronic Heart Failure Complicated by Primary Biliary Cholangitis and Skeletal Myopathy.

Several autoantigens related to inflammatory myopathy have been identified. Antimitochondrial antibody M2 (AMA-M2) is known as one of the serologic hallmarks of primary biliary cholangitis (PBC). There have been several reports on the association between AMA-M2 and various types of inflammatory myopathy, including cardiomyopathy. We report a case of a 58-year-old man with decompensated heart failure who also had PBC and skeletal inflammatory myopathy. Endomyocardial biopsy revealed severe fibrotic replacement of the myocardium without massive inflammatory infiltration, which was pathologically similar to what happens in dilated cardiomyopathy (DCM). Although the potential relationship between chronic autoimmune inflammation and DCM has been discussed, the concept of the inflammatory DCM has not yet been established. When we see elevated liver enzymes, and which is not simply due to congestive hepatopathy, we should consider the coexisting disease such as PBC.

Gender-specific development of experimental autoimmune cholangitis induced by double-stranded RNA.

Here we investigated the gender difference in murine cholangitis resembling human primary biliary cholangitis (PBC) caused by synthetic double-stranded RNA, and underlying hepatic innate immune responses. Female C57Bl/6 mice given repeated injections of polyinosinic-polycytidylic acid (poly I:C) for 24 weeks developed overt cholangitis with positive serum anti-mitochondria-M2 antibody, whereas male mice showed minimal pathological changes without induction in autoantibody. Poly I:C induced hepatic inflammatory cytokines and type-I interferons predominantly in females. Hepatic expression levels of toll-like receptor (TLR) 3 and melanoma differentiation-associated protein (MDA) 5 were equivalent in both genders; however, both mRNA and protein levels of retinoic acid-inducible gene (RIG)-I were nearly doubled in female livers. Following 4-week injections of poly I:C, not only hepatic RIG-I, but also TLR3 and MDA5 showed female-predominance. Moreover, hepatic RIG-I levels were 25% lower in ovariectomized mice, whereas supplementation of 17 ß-estradiol enhanced hepatic RIG-I expression, as well as cytokine induction. These results clearly indicate that hepatic RIG-I expression is potentiated by estrogen, and triggers gender-dependent hepatic innate immune response against double-stranded RNA, which most likely play a pivotal role in the pathogenesis of autoimmune cholangiopathies including PBC.

Autoimmunity affecting the biliary tract fuels the immunosurveillance of cholangiocarcinoma.

Cholangiocarcinoma (CCA) results from the malignant transformation of cholangiocytes. Primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC) are chronic diseases in which cholangiocytes are primarily damaged. Although PSC is an inflammatory condition predisposing to CCA, CCA is almost never found in the autoimmune context of PBC. Here, we hypothesized that PBC might favor CCA immunosurveillance. In preclinical murine models of cholangitis challenged with syngeneic CCA, PBC (but not PSC) reduced the frequency of CCA development and delayed tumor growth kinetics. This PBC-related effect appeared specific to CCA as it was not observed against other cancers, including hepatocellular carcinoma. The protective effect of PBC was relying on type 1 and type 2 T cell responses and, to a lesser extent, on B cells. Single-cell TCR/RNA sequencing revealed the existence of TCR clonotypes shared between the liver and CCA tumor of a PBC host. Altogether, these results evidence a mechanistic overlapping between autoimmunity and cancer immunosurveillance in the biliary tract.

[Immune pathogenesis of primary biliary cholangitis].

Primary biliary cholangitis (PBC) is an autoimmune liver disease, mainly characterized by chronic progressive cholestasis. The root cause of PBC is the loss of immune tolerance to autoantigen E2 subunit of pyruvate dehydrogenase (PDC-E2). The unique immunobiological characteristics of intrahepatic bile duct epithelial cells make it an active participant in the pathogenesis of PBC. In recent years, the detection rate of PBC has been increasing year by year, but the clinical situation of ursodeoxycholic acid monotherapy has not changed. Therefore, an in-depth understanding of the immune pathogenesis of PBC will help clinicians better prevent and treat diseases.

Suppression of systemic inflammation and signs of acute and chronic cholangitis by multi-kinase inhibitor 1-(4-Cl-benzyl)-3-chloro-4-(CF3-phenylamino)-1H-pyrrole-2,5-dione.

An aberrant activity of growth factor receptors followed by excessive cell proliferation plays a significant role in pathogenesis of cholangitis. Therefore, inhibition of these processes could be a fruitful therapeutic strategy. The effects of multi-kinase inhibitor 1-(4-Cl-benzyl)-3-chloro-4-(CF3-phenylamino)-1H-pyrrole-2,5-dione (MI-1) on the hepatic and systemic manifestations of acute and chronic cholangitis in rats were addressed. MI-1 (2.7 mg/kg per day) was applied to male rats that experienced α-naphthylisothiocyanate-induced acute (3 days) or chronic (28 days) cholangitis. Liver autopsy samples, blood serum markers, and leukograms were studied. MI-1 localization in liver cells and its impact on viability of HepG2 (human hepatoma), HL60 (human leukemia), and NIH3T3 (normal murine fibroblasts) cell lines and lymphocytes of human peripheral blood (MTT, DNA fragmentation, DNA comet assays, Propidium Iodide staining) were assessed. Under both acute and chronic cholangitis, MI-1 substantially reduced liver injury, fibrosis, and inflammatory scores (by 46-86%) and normalized blood serum markers and leukograms. Moreover, these effects were preserved after a 28-day recovery period (without any treatment). MI-1 inhibited the HL60, HepG2 cells, and human lymphocytes viability (IC50 0.6, 9.5 and 8.3 µg/ml, respectively), while NIH3T3 cells were resistant to that. Additionally, HepG2 cells and lymphocytes being incubated with MI-1 demonstrated insignificant pro-apoptotic and pro-necrotic changes and DNA single-strand breaks, suggesting that MI-1 effects in liver might be partly caused by its cytotoxic action towards liver cells and lymphocytes. In conclusion, MI-1 attenuated the systemic inflammation and signs of acute and chronic cholangitis partly through cytotoxicity towards cells of hepatic and leukocytic origin.

NAFLD exacerbates cholangitis and promotes cholangiocellular carcinoma in mice.

Nonalcoholic fatty liver disease (NAFLD) is an increasingly common condition, affecting up to 25% of the population worldwide. NAFLD has been linked to several conditions, including hepatic inflammation, fibrosis, and hepatocellular carcinoma (HCC), however the role of NAFLD in cholangitis and the development of cholangiocellular carcinoma (CCC) remains poorly understood. This study investigated whether a high-fat diet (HFD) promotes cholangitis and the development of CCC in mice. We used liver-specific E-cadherin gene (CDH1) knockout mice, CDH1∆Liv , which develop spontaneous inflammation in the portal areas along with periductal onion skin-like fibrosis, similar to that of primary sclerosing cholangitis (PSC). An HFD or normal diet (ND) was fed to CDH1∆Liv mice for 7 mo. In addition, CDH1∆Liv mice were crossed with LSL-KrasG12D mice, fed an HFD, and assessed in terms of liver tumor development. The extent of cholangitis and number of bile ductules significantly increased in mice fed an HFD compared with ND-administered CDH1∆Liv mice. The numbers of Sox9 and CD44-positive stem cell-like cells were significantly increased in HFD mice. LSL-KrasG12D /CDH1∆Liv HFD mice exhibited increased aggressiveness along with the development of numerous HCC and CCC, whereas LSL-KrasG12D /CDH1∆Liv ND mice showed several macroscopic tumors with both HCC and CCC components. In conclusion, NAFLD exacerbates cholangitis and promotes the development of both HCC and CCC in mice.

Cholangiopathy and Biliary Fibrosis in Cyp2c70-Deficient Mice Are Fully Reversed by Ursodeoxycholic Acid.

BACKGROUND AND AIMS: Bile acids (BAs) aid intestinal fat absorption and exert systemic actions by receptor-mediated signaling. BA receptors have been identified as drug targets for liver diseases. Yet, differences in BA metabolism between humans and mice hamper translation of pre-clinical outcomes. Cyp2c70-ablation in mice prevents synthesis of mouse/rat-specific muricholic acids (MCAs), but potential (patho)physiological consequences of their absence are unknown. We therefore assessed age- and gender-dependent effects of Cyp2c70-deficiency in mice. METHODS: The consequences of Cyp2c70-deficiency were assessed in male and female mice at different ages. RESULTS: Cyp2c70-/- mice were devoid of MCAs and showed high abundances of chenodeoxycholic and lithocholic acids. Cyp2c70-deficiency profoundly impacted microbiome composition. Bile flow and biliary BA secretion were normal in Cyp2c70-/- mice of both sexes. Yet, the pathophysiological consequences of Cyp2c70-deficiency differed considerably between sexes. Three-week old male Cyp2c70-/- mice showed high plasma BAs and transaminases, which spontaneously decreased thereafter to near-normal levels. Only mild ductular reactions were observed in male Cyp2c70-/- mice up to 8 months of age. In female Cyp2c70-/- mice, plasma BAs and transaminases remained substantially elevated with age, gut barrier function was impaired and bridging fibrosis was observed at advanced age. Addition of 0.1% ursodeoxycholic acid to the diet fully normalized hepatic and intestinal functions in female Cyp2c70-/- mice. CONCLUSION: Cyp2c70-/- mice show transient neonatal cholestasis and develop cholangiopathic features that progress to bridging fibrosis in females only. These consequences of Cyp2c70-deficiency are restored by treatment with UDCA, indicating a role of BA hydrophobicity in disease development.

Recreational ketamine-induced cholangiopathy and ulcerative cystitis.

Ketamine is a versatile analgesic that has become an increasingly popular recreational drug. Chronic ketamine use has been found to cause biliary duct damage and bladder dysfunction. Ketamine-induced cholangiopathy and ulcerative cystitis are uncommon diagnoses presenting with nonspecific symptoms, creating diagnostic challenges for emergency physicians. We report a case of a teenage patient with the rare simultaneous presentation of ketamine-induced cholangiopathy and ulcerative cystitis. Due to increased recreational and chronic ketamine use, cases of ketamine-induced cholangiopathy and ulcerative cystitis are likely to rise with the increased knowledge, awareness, and reporting of these entities by radiologists and emergency physicians.

IL-17A/F enable cholangiocytes to restrict T cell-driven experimental cholangitis by upregulating PD-L1 expression.

BACKGROUND & AIMS: IL-17A-producing T cells are present in autoimmune cholestatic liver diseases; however, little is known about the contribution of IL-17 to periductal immune responses. Herein, we investigated the role of IL-17 produced by antigen-specific CD8+ T cells in a mouse model of cholangitis and in vitro in human cholangiocyte organoids. METHODS: K14-OVAp mice express a major histocompatibility complex I-restricted ovalbumin (OVA) peptide sequence (SIINFEKL) on cholangiocytes. Cholangitis was induced by the adoptive transfer of transgenic OVA-specific ovalbumin transgene (OT)-1 CD8+ T cells that either had OT-1wt or lacked IL-17A/F (OT-1IL17ko). The response of mouse and human cholangiocytes/organoids to IL-17A was assessed in vitro. RESULTS: Transfer of OVA-specific OT-1IL17ko cells significantly aggravated periductal inflammation in K14-OVAp recipient mice compared with transfer of OT-1wt T cells. OT-1IL17ko T cells were highly activated in the liver and displayed increased cytotoxicity and proliferation. IL-17A/F produced by transferred OT-1wt CD8+ T cells induced upregulation of the inhibitory molecule programmed cell death ligand 1 (PD-L1) on cholangiocytes, restricting cholangitis by limiting cytotoxicity and proliferation of transferred cells. In contrast, OT-1IL17ko T cells failed to induce PD-L1 on cholangiocytes, resulting in uncontrolled expansion of cytotoxic CD8+ T cells and aggravated cholangitis. Blockade of PD-L1 after transfer of OT-1wt T cells with anti-PD-L1 antibody also resulted in aggravated cholangitis. Using human cholangiocyte organoids, we were able to confirm that IL-17A induces PD-L1 expression in cholangiocytes. CONCLUSIONS: We demonstrate that by upregulating PD-L1 on cholangiocytes, IL-17 has an important role in restricting cholangitis and protecting against CD8+ T cell-mediated inflammatory bile duct injury. Caution should be exercised when targeting IL-17 for the treatment of cholangitis. LAY SUMMARY: IL-17 is assumed to be a driver of inflammation in several autoimmune diseases, such as psoriasis. IL-17 is also present in inflammatory diseases of the bile duct, but its role in these conditions is not clear, as the effects of IL-17 depend on the context of its expression. Herein, we investigated the role of IL-17 in an experimental autoimmune cholangitis mouse model, and we identified an important protective effect of IL-17 on cholangiocytes, enabling them to downregulate bile duct inflammation via checkpoint inhibitor PD-L1.

New paradigms of USP53 disease: normal GGT cholestasis, BRIC, cholangiopathy, and responsiveness to rifampicin.

Biallelic variants in the USP53 gene have recently been reported to segregate with normal gamma glutamyltransferase (GGT) cholestasis. Using whole-exome sequencing (WES), we detected two USP53 homozygous variants (c.951delT; p. Phe317fs and c.1744C>T; p. Arg582*) in five additional cases, including an unpublished cousin of a previously described family with intractable itching and normal GGT cholestasis. Three patients, a child and two adults, presented with recurrent episodes of normal GGT cholestasis, consistent with a diagnosis of benign recurrent intrahepatic cholestasis (BRIC). Cholangiopathic changes, possibly autoimmune in origin, were recognized in some patients. Additional phenotypic details in one patient included an enlarged left kidney, and speech/developmental delay. Notably, two patients exhibited a complete response to rifampicin, and one responded to ursodeoxycholic acid (UDCA). Two adult patients were suspected to have autoimmune liver disease and treated with steroids. This report describes new cases of USP53 disease presenting with normal GGT cholestasis or BRIC in three children and two adults. We also describe the novel finding of a dramatic response to rifampicin. The association of cholangiopathy with normal GGT cholestasis provides a diagnostic challenge and remains poorly understood.

NLRP3 receptor contributes to protection against experimental antigen-mediated cholangitis.

Inflammatory diseases of the bile ducts like primary sclerosing colangitis (PSC) are characterized by a robust cellular response targeting the biliary epithelium leading to chronic inflammation and fibrosis. Driving fibro-inflammatory diseases, NOD-like receptors such as NLRP3 have been identified as a central component to immune-mediated pathology. However, to date the role of NLRP3 in biliary diseases has been poorly explored. Here, we addressed the role of NLRP3 in the OVAbil mouse model of antigen-mediated cholangitis. As obesity continues to spread worldwide, we also evaluated the NLRP3 response in experimental cholangitis after high-fat diet exposure. We compared the extent of histopathological liver damage between OVAbil and OVAbilxNLRP3-/- mice after either a standard chow or a high-fat diet. Infiltrating immune cells were characterized by flow cytometry and levels of cytokines, chemokines and liver enzymes in blood samples were analyzed at the end of the experiment. We observed a more severe histopathological phenotype of cholangitis in absence of NLRP3, characterized by loss of bile ducts and larger inflammatory foci and higher levels of IL- 6 and CXCL10 as compared with NLRP3 sufficient mice. This phenotype was further exaggerated in the context of obesity, where cholangitis induced in NLRP3-deficient obese mice resulted in further exacerbated histopathology and increased levels of IL-13 and TNFα, suggesting a diet-specific profile. The absence of NLRP3 caused a supressed IL-17 response. In summary, our data suggest that activation of NLRP3 attenuates this antigen-mediated OVAbil model of cholangitis.