Biliary Inflammation Research Articles

Liver transplant in primary sclerosing cholangitis: Current trends and future directions.

Primary sclerosing cholangitis (PSC) is a chronic and progressive immune-mediated cholangiopathy causing biliary tree inflammation and scarring, leading to liver cirrhosis and end-stage liver disease. Diagnosis of PSC is challenging due to its nonspecific symptoms and overlap with other liver diseases. Despite the rising incidence of PSC, there is no proven medical therapy that can alter the natural history of the disease. While liver transplantation (LT) is the most effective approach for managing advanced liver disease caused by PSC, post-transplantation recurrence of PSC remains a challenge. Therefore, ongoing research aims to develop better therapies for PSC, and continued efforts are necessary to improve outcomes for patients with PSC. This article provides an overview of PSC's pathogenesis, clinical presentation, and management options, including LT trends and future aspects. It also highlights the need for improved therapeutic options and ethical considerations in providing equitable access to LT for patients with PSC. Additionally, the impact of liver transplant on the quality of life and psychological outcomes of patients with PSC is discussed. Ongoing research into PSC's pathogenesis and post-transplant recurrence is crucial for improved understanding of the disease and more effective treatment options.

Prognostic impact of the Controlling Nutritional Status Score in patients with biliary tract cancer: a systematic review and meta-analysis.

Biliary tract cancer (BTC) is a malignancy associated with unfavorable outcomes. Advanced BTC patients have a propensity to experience compromised immune and nutritional status as a result of obstructive jaundice and biliary inflammation. Currently, there is a lack of consensus on the impact of the Controlling Nutritional Status (CONUT) score in the context of BTC prognosis. The purpose of this study is to conduct a meta-analysis on the association between CONUT and the prognosis of patients suffering from BTC. A defined search strategy was implemented to search the PubMed, Embase, and Web of Science databases for eligible studies published until March 2023, with a focus on overall survival (OS), relapse-free survival/recurrence-free survival(RFS), and relevant clinical characteristics. The prognostic potential of the CONUT score was evaluated using hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs). In this meta-analysis, a total of 1409 patients from China and Japan were involved in 9 studies. The results indicated that the CONUT score was significantly correlated with worse OS (HR=2.13, 95% CI 1.61-2.82, P<0.0001) and RFS (HR=1.83, 95% CI 1.44-2.31, P<0.0001) in patients with BTC. And, the analysis showed that a high CONUT score was significantly associated with clinical characteristics such as jaundice (OR=1.60, 95% CI=1.14-2.25, P=0.006), poorly differentiated tumor (OR=1.43, 95% CI=1.03-1.99, P=0.03), pT3 and 4 stage of the tumor (OR=1.87, 95% CI=1.30-2.68, P=0.0007), and complications of Clavien-Dindo classification grade IIIa or higher (OR=1.79, 95% CI=1.03-3.12, P=0.04). This meta-analysis indicates that a high CONUT score can serve as a significant prognostic indicator for survival outcomes among patients diagnosed with BTC.

Histologic characterization of the major duodenal papilla and association with concurrent biliary, pancreatic, and intestinal pathology in cats.

Conjoining of the major pancreatic duct and common bile duct at the major duodenal papilla (MDP) is suspected to predispose cats to the clinical syndrome of "triaditis." However, microanatomy of the MDP or presence of lesions at the MDP has not been assessed in cats with or without triaditis. The aims of this study were to characterize feline MDP histomorphology and to identify associations between MDP anatomy/disease and the presence of biliary, pancreatic, or intestinal inflammation or neoplasia. Histologic assessment was prospectively performed on the MDP, duodenum, jejunum, ileum, liver, and pancreas from 124 client-owned cats undergoing postmortem examination. The majority of cats (104/124, 84%) had a complex ductular network at the MDP, with no distinction between pancreatic and common bile ducts. Lymphoid aggregates at the MDP were common (63/124, 51%). Inflammation of the MDP (MDPitis) was present in 35 of 124 cats (28%) and was often concurrent with cholangitis, pancreatitis, or enteritis (32/35, 91%), but was only associated with enteritis (19/35, 54%, P < .05). Triaditis was less common (19/124, 15%), but was associated with both conjoined MDP anatomy (19/19, 100%, P < .05) and MDPitis (12/19, 63%, P < .05). Neoplasia was present in 37 of 124 cats (29%), with lymphoma (28/37, 78%) predominating. Enteropathy-associated T-cell lymphoma type 2 (EATL2) was most common (n = 16/37, 43%) and was associated with triaditis and MDPitis (P < .05). These findings suggest that anatomy, immune activation, and/or inflammation of the MDP may play a role in the pathogenesis of triaditis. Further studies are needed to elucidate the relationships between triaditis, MDPitis, and EATL2.

Itaconate inhibits CD103 + T RM cells and alleviates hepatobiliary injury in mouse models of primary sclerosing cholangitis.

Primary sclerosing cholangitis (PSC) is a chronic progressive liver disease characterized by the infiltration of intrahepatic tissue-resident memory CD8 + T cells (T RM ). Itaconate has demonstrated therapeutic potential in modulating inflammation. An unmet need for PSC is the reduction of biliary inflammation, and we hypothesized that itaconate may directly modulate pathogenic T RM . The numbers of intrahepatic CD103 + T RM were evaluated by immunofluorescence in PSC (n = 32), and the serum levels of itaconate in PSC (n = 64), primary biliary cholangitis (PBC) (n = 60), autoimmune hepatitis (AIH) (n = 49), and healthy controls (n = 109) were determined by LC-MS/MS. In addition, the frequencies and immunophenotypes of intrahepatic T RM using explants from PSC (n = 5) and healthy donors (n = 6) were quantitated by flow cytometry. The immunomodulatory properties of 4-octyl itaconate (4-OI, a cell-permeable itaconate derivative) on CD103 + T RM were studied in vitro. Finally, the therapeutic potential of itaconate was studied by the administration of 4-OI and deficiency of immune-responsive gene 1 (encodes the aconitate decarboxylase producing itaconate) in murine models of PSC. Intrahepatic CD103 + T RM was significantly expanded in PSC and was positively correlated with disease severity. Serum itaconate levels decreased in PSC. Importantly, 4-OI inhibited the induction and effector functions of CD103 + T RM in vitro. Mechanistically, 4-OI blocked DNA demethylation of RUNX3 in CD8 + T cells. Moreover, 4-OI reduced intrahepatic CD103 + T RM and ameliorated liver injury in murine models of PSC. Itaconate exerted immunomodulatory activity on CD103 + T RM in both in vitro and murine PSC models. Our study suggests that targeting pathogenic CD103 + T RM with itaconate has therapeutic potential in PSC.

CCL24 regulates biliary inflammation and fibrosis in primary sclerosing cholangitis.

ˆCCL24 is a pro-fibrotic, pro-inflammatory chemokine expressed in several chronic fibrotic diseases. In the liver, CCL24 plays a role in fibrosis and inflammation, and blocking CCL24 led to reduced liver injury in experimental models. We studied the role of CCL24 in primary sclerosing cholangitis (PSC) and evaluated the potential therapeutic effect of blocking CCL24 in this disease. Multidrug resistance gene 2-knockout (Mdr2-/-) mice demonstrated CCL24 expression in liver macrophages and were used as a relevant experimental PSC model. CCL24-neutralizing monoclonal antibody, CM-101, significantly improved inflammation, fibrosis, and cholestasis-related markers in the biliary area. Moreover, using spatial transcriptomics, we observed reduced proliferation and senescence of cholangiocytes following CCL24 neutralization. Next, we demonstrated that CCL24 expression was elevated under pro-fibrotic conditions in primary human cholangiocytes and macrophages, and it induced proliferation of primary human hepatic stellate cells and cholangiocytes, which was attenuated following CCL24 inhibition. Correspondingly, CCL24 was found to be highly expressed in liver biopsies of patients with PSC. CCL24 serum levels correlated with Enhanced Liver Fibrosis score, most notably in patients with high alkaline phosphatase levels. These results suggest that blocking CCL24 may have a therapeutic effect in patients with PSC by reducing liver inflammation, fibrosis, and cholestasis.

The association of immune-related genes and the potential role of IL10 with biliary atresia.

Biliary atresia (BA) is a severe immune-related disease that is characterized by biliary obstruction and cholestasis. The etiology of BA is unclear, our aim was to explore the relationship between biliary tract inflammation and immune-related genes. We selected 14 SNPs in 13 immune-related genes and investigated their associations with BA by using a large case‒control cohort with a total of 503 cases and 1473 controls from southern China. SNP rs1518111 in interleukin10 (IL10) was identified as associated with BA (P = 5.79E-03; OR: 0.80; 95% CI: 0.68-0.94). The epistatic effects of the following pairwise interactions among these SNPs were associated with BA: signal transducer and activator of transcription 4 (STAT4) and chemokine (C-X-C motif) ligand 3 (CXCL3); STAT4 and damage-regulated autophagy modulator1 (DRAM1); CXCL3 and RAD51 paralog B (RAD51B); and interferon gamma (IFNG) and interleukin26 (IL26). Furthermore, we explored the potential role of IL-10 in the pathogenesis of the neonatal mouse model of BA. IL-10 effectively prevented biliary epithelial cell injury and biliary obstruction in murine BA as well as inhibit the activation of BA-related immune cells. In conclusion, this study provided strong evidence implicating IL10 as a susceptibility gene for BA in the southern Chinese population. This study provided strong evidence implicating IL10 as a susceptibility gene for BA in the southern Chinese population. This study could infer that IL-10 may play a protective role in BA mouse model. We found that four SNPs (rs7574865, rs352038, rs4622329, and rs4902562) have genetic interactions.

Bacteriophage therapy against pathological Klebsiella pneumoniae ameliorates the course of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is characterized by progressive biliary inflammation and fibrosis. Although gut commensals are associated with PSC, their causative roles and therapeutic strategies remain elusive. Here we detect abundant Klebsiella pneumoniae (Kp) and Enterococcus gallinarum in fecal samples from 45 PSC patients, regardless of intestinal complications. Carriers of both pathogens exhibit high disease activity and poor clinical outcomes. Colonization of PSC-derived Kp in specific pathogen-free (SPF) hepatobiliary injury-prone mice enhances hepatic Th17 cell responses and exacerbates liver injury through bacterial translocation to mesenteric lymph nodes. We developed a lytic phage cocktail that targets PSC-derived Kp with a sustained suppressive effect in vitro. Oral administration of the phage cocktail lowers Kp levels in Kp-colonized germ-free mice and SPF mice, without off-target dysbiosis. Furthermore, we demonstrate that oral and intravenous phage administration successfully suppresses Kp levels and attenuates liver inflammation and disease severity in hepatobiliary injury-prone SPF mice. These results collectively suggest that using a lytic phage cocktail shows promise for targeting Kp in PSC.

Liver manifestations of tick-borne diseases.

Liver manifestations of tick-borne diseases.

Breach of tolerance versus burden of bile acids: Resolving the conundrum in the immunopathogenesis and natural history of primary biliary cholangitis

Primary biliary cholangitis (PBC) is a classic autoimmune disease due to the loss of tolerance to self-antigens. Bile acids (BA) reportedly play a major role in biliary inflammation and/or in the modulation of dysregulated immune responses in PBC. Several murine models have indicated that molecular mimicry plays a role in autoimmune cholangitis; however, they have all been limited by the relative failure to develop hepatic fibrosis. We hypothesized that species-specific differences in the BA composition between mice and humans were the primary reason for this limited pathology. Here, we aimed to study the impact of human-like hydrophobic BA composition on the development of autoimmune cholangitis and hepatic fibrosis. We took advantage of a unique construct, Cyp2c70/Cyp2a12 double knockout (DKO) mice, which have human-like BA composition, and immunized them with a well-defined mimic of the major mitochondrial autoantigen of PBC, namely 2-octynoic acid (2OA). 2OA-treated DKO mice were significantly exacerbated portal inflammation and bile duct damage with increased Th1 cytokines/chemokines at 8 weeks post-initial immunization. Most importantly, there was clear progression of hepatic fibrosis and increased expression of hepatic fibrosis-related genes. Interestingly, these mice demonstrated increased serum BA concentrations and decreased biliary BA concentrations; hepatic BA levels did not increase because of the upregulation of transporters responsible for the basolateral efflux of BA. Furthermore, cholangitis and hepatic fibrosis were more advanced at 24 weeks post-initial immunization. These results indicate that both the loss of tolerance and the effect of hydrophobic BA are essential for the progression of PBC.

Early Deregulation of Cholangiocyte NR0B2 During Primary Sclerosing Cholangitis.

Primary sclerosing cholangitis (PSC) is a probable autoimmune liver disease characterized by persistent and progressive biliary inflammation that leads to biliary infection, cirrhosis, or cholangiocarcinoma. Genome-wide omics data are scarce regarding this severe disease. MEDLINE database gene prioritization by text mining (biliary inflammation, biliary fibrosis, biliary stasis) was integrated in distinct omics data: (1) PSC liver transcriptome training and validation cohorts, (2) farnesoid X receptor (FXR) mice liver transcriptome subjected to an FXR agonist or FXR knockout mice; (3) liver single-cell transcriptome of the Abcb4-/- mice model of PSC. A liver molecular network highlighted the involvement of nuclear receptor subfamily 0 group B member 2 (NR0B2) and its associated nuclear receptor FXR in a metabolic cascade that may influence the immune response. NR0B2 upregulation in PSC liver was independent of gender, age, body mass index, liver fibrosis, and PSC complications. Heterogeneity of NR0B2 upregulation was found in cholangiocyte cell types in which the NR0B2-based cell fate decision revealed the involvement of several metabolic pathways for detoxification (sulfur, glutathione derivative, and monocarboxylic acid metabolisms). Genes potentially implicated in carcinogenesis were also discovered on this cholangiocyte trajectory: GSTA3, inhibitor of DNA binding 2, and above all, TMEM45A, a transmembrane molecule from the Golgi apparatus considered as oncogenic in several cancers. By revisiting PSC through PubMed data mining, we evidenced the early cholangiocyte deregulation of NR0B2, highlighting a metabolic and premalignant reprogramming of the cholangiocyte cell type. The therapeutic targeting of NR0B2 could potentiate that of FXR and enable action on early events of the disease and prevent its progression.

Inhibiting Wnt Signaling Reduces Cholestatic Injury by Disrupting the Inflammatory Axis

β-Catenin, the effector molecule of the Wnt signaling pathway, has been shown to play a crucial role in bile acid homeostasis through direct inhibition of farnesoid X receptor (FXR), which has pleiotropic effects on bile acid homeostasis. We hypothesize that simultaneous suppression of β-catenin signaling and activation of FXR in a mouse model of cholestasis will reduce injury and biliary fibrosis through inhibition of bile acid synthesis. To induce cholestasis, we performed bile duct ligation (BDL) on wild-type male mice. Eight hours after surgery, mice received FXR agonists obeticholic acid, tropifexor, or GW-4064 or Wnt inhibitor Wnt-C59. Severity of cholestatic liver disease and expression of target genes were evaluated after either 5 days or 12 days of treatment. We found that although the FXR agonists worsened BDL-induced injury and necrosis after 5 days, Wnt-C59 did not. After 12 days of BDL, Wnt-C59 treatment, but not GW-4064 treatment, reduced both the number of infarcts and the number of inflammatory cells in liver. RNA sequencing analysis of whole livers revealed a notable suppression of nuclear factor kappa B signaling when Wnt signaling is inhibited. We then analyzed transcriptomic data to identify a cholangiocyte-specific signature in our model and demonstrated that Wnt-C59-treated livers were enriched for genes expressed in quiescent cholangiocytes, whereas genes expressed in activated cholangiocytes were enriched in BDL alone. A similar decrease in biliary injury and inflammation occurred in Mdr2 KO mice treated with Wnt-C59. Inhibiting Wnt signaling suppresses cholangiocyte activation and disrupts the nuclear factor kappa B-dependent inflammatory axis, reducing cholestatic-induced injury.

Loss of apical sodium bile acid transporter alters bile acid circulation and reduces biliary damage in cholangitis.

Primary sclerosing cholangitis (PSC) is characterized by increased ductular reaction (DR), liver fibrosis, hepatic total bile acid (TBA) levels, and mast cell (MC) infiltration. Apical sodium BA transporter (ASBT) expression increases in cholestasis, and ileal inhibition reduces PSC phenotypes. FVB/NJ and multidrug-resistant 2 knockout (Mdr2-/-) mice were treated with control or ASBT Vivo-Morpholino (VM). We measured 1) ASBT expression and MC presence in liver/ileum; 2) liver damage/DR; 3) hepatic fibrosis/inflammation; 4) biliary inflammation/histamine serum content; and 5) gut barrier integrity/hepatic bacterial translocation. TBA/BA composition was measured in cholangiocyte/hepatocyte supernatants, intestine, liver, serum, and feces. Shotgun analysis was performed to ascertain microbiome changes. In vitro, cholangiocytes were treated with BAs ± ASBT VM, and histamine content and farnesoid X receptor (FXR) signaling were determined. Treated cholangiocytes were cocultured with MCs, and FXR signaling, inflammation, and MC activation were measured. Human patients were evaluated for ASBT/MC expression and histamine/TBA content in bile. Control patient- and PSC patient-derived three-dimensional (3-D) organoids were generated; ASBT, chymase, histamine, and fibroblast growth factor-19 (FGF19) were evaluated. ASBT VM in Mdr2-/- mice decreased 1) biliary ASBT expression, 2) PSC phenotypes, 3) hepatic TBA, and 4) gut barrier integrity compared with control. We found alterations between wild-type (WT) and Mdr2-/- mouse microbiome, and ASBT/MC and bile histamine content increased in cholestatic patients. BA-stimulated cholangiocytes increased MC activation/FXR signaling via ASBT, and human PSC-derived 3-D organoids secrete histamine/FGF19. Inhibition of hepatic ASBT ameliorates cholestatic phenotypes by reducing cholehepatic BA signaling, biliary inflammation, and histamine levels. ASBT regulation of hepatic BA signaling offers a therapeutic avenue for PSC.NEW & NOTEWORTHY We evaluated knockdown of the apical sodium bile acid transporter (ASBT) using Vivo-Morpholino in Mdr2KO mice. ASBT inhibition decreases primary sclerosing cholangitis (PSC) pathogenesis by reducing hepatic mast cell infiltration, altering bile acid species/cholehepatic shunt, and regulating gut inflammation/dysbiosis. Since a large cohort of PSC patients present with IBD, this study is clinically important. We validated findings in human PSC and PSC-IBD along with studies in novel human 3-D organoids formed from human PSC livers.

Forkhead box M1 recruits FoxP3+ Treg cells to induce immune escape in hilar cholangiocarcinoma.

ObjectiveHilar cholangiocarcinoma (HCCA) is a malignancy related to chronic biliary tract inflammation. Tumor immune escape is a necessary process of tumorigenesis. Forkhead box M1 (FoxM1) could affect the progression of various carcinomas. This study attempted to elaborate on the mechanism of FoxM1 in HCCA immune escape.MethodsHCCA cell lines were collected to measure the expression of FoxM1 and FoxP3. CD8+ T cells were extracted to establish the co‐culture system with HCCA cells and Treg cells. pcDNA3.1‐FoxM1 or si‐FoxP3 was transfected into HCCA cells in the co‐culture system. HCCA cell viability, mobility, and invasiveness as well as levels of transforming growth factor (TGF)‐β and interleukin (IL)‐6 were evaluated. The binding relation between FoxM1 and FoxP3 promoter was verified. HCCA cells with pcDNA3.1‐FoxM1 were subcutaneously injected into mice to establish the xenograft mouse models.ResultsFoxM1 and FoxP3 were overexpressed in HCCA cells. The co‐culture of CD8+ T and HCCA cells inhibited HCCA cell activity and Treg cells limited CD8+ T killing. FoxM1 overexpression strengthened the inhibiting role of Treg cells in CD8+ T killing, upregulated TGF‐β and IL‐6 levels, and encouraged HCCA immune escape. FoxM1 bound to the FoxP3 promoter region to promote FoxP3 transcription. Silencing of FoxP3 neutralized the promoting role of FoxM1 overexpression in Treg cell immunosuppression and HCCA cell immune escape. FoxM1 aggravated tumor development, upregulated FoxP3 expression, increased Treg cells, and reduced CD8+ T cells.ConclusionFoxM1 bound to the FoxP3 promoter region to promote FoxP3 transcription and recruited FoxP3+ Treg cells, thereby inducing HCCA immune escape.

MR elastography in primary sclerosing cholangitis: a pictorial review.

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by biliary ductal inflammation and fibrosis causing both intrahepatic and extrahepatic biliary strictures and dilatation. There is currently no effective medical treatment and the disease leads to cirrhosis and liver failure, with patients often requiring liver transplantation in end-stage disease. Liver fibrosis is one of the most important factors in determining patient outcome in PSC, and the diagnosis and monitoring of fibrosis are vital to patient care. MRI with magnetic resonance cholangiopancreatography is the non-invasive imaging modality of choice in PSC and is useful for the evaluation of parenchymal and biliary changes. Biliary ductal abnormalities, however, cannot always predict the presence of liver fibrosis and alternative means are needed. MR Elastography (MRE) is the most accurate non-invasive method for assessing liver fibrosis and is particularly helpful in PSC due to unique hepatic manifestations. Like other non-invasive modalities, MRE measures liver stiffness as an indirect method for assessing fibrosis. Given the ability of MRE to assess liver fibrosis and the importance of fibrosis in PSC patients, MRE can reliably predict patient outcome. In this pictorial review, we will review MR findings of PSC, with an emphasis on MRE, and demonstrate scenarios where MRE is particularly helpful in evaluating PSC patients.

Targeting Galanin Receptor Signaling as a Novel Therapeutic Strategy for the Treatment of Fatty Liver Disease

BackgroundNon‐alcoholic fatty liver disease (NAFLD) is a common liver disease in the United States and is associated with dysregulated lipid metabolism and fat accumulation in hepatocytes (i.e. steatosis) leading to inflammation and fibrosis and cirrhosis. Galanin (Gal) is a neuropeptide with a role in food intake behavior and chronic upregulation of Gal is associated with increases in serum triglycerides, hyperinsulinemia, impaired glucose tolerance and hepatic steatosis. Targeting Gal receptor (GalR) signaling has been shown to have antifibrotic in models of cholestatic liver disease although the effects in NAFLD is unknown. The aim of this study was to evaluate the Gal/GalR axis in NAFLD and determined the effects of Gal Inhibition on the pathogenesis of NAFLD.MethodsC57Bl6 mice were fed a western diet (WD) consisting of high fat/high sugar/high cholesterol for a total of 16 weeks. At the 4 week time point, mice were treated with the GalR1/GalR2 antagonist, M40 (1 nmol, 3X per week for the duration of the experiment), or corresponding vehicle control. Serum and liver assays of Gal, triglycerides, and cholesterol were performed using commercially available kits. The expression of Gal, GalR1, GalR2, markers of steatosis (perilipin 2, PLIN2), biliary hyperplasia (cytokeratin 19, CK19), fibrosis (collagen type 1A1, Col1A1; α‐smooth muscle actin, α‐SMA) and inflammation (chemokine C‐C motif ligand 2, CCL2; tumor necrosis factor‐α, TNFα) by qPCR and immunostaining. Liver macrophages CD11b+ and CD68+ were quantified by immunohistochemistry (IHC). Liver lipid droplets (LD) were stained with Oil Red O. In vitro, HepG2 cells were used to assess the effects of M40 on palmitate (PA)‐induced LD formation.ResultsGal was significantly increased in the serum and liver of WD‐fed mice, with a corresponding increase in GalR1 and GalR2 expression. WD‐mice exhibited significant increase in serum transaminases, triglycerides and cholesterol compared to control mice, and M40 significantly reduced these indicators of liver injury. A drastic decrease in liver steatosis was also observed in M40‐treated WD‐mice compared to vehicle‐treated WD‐mice. M40 treatment also ameliorated WD‐induced increase in ductular reaction, fibrosis and liver inflammation in NAFLD mice. In vitro experiments confirmed that M40 decreased PA‐induced steatosis of HepG2.ConclusionsThe expression of Gal and its receptors GalR1 and GalR2, is enhanced in livers of mice on a WD. Treatment of WD‐fed mice with M40 reduces steatosis, intrahepatic biliary mass, fibrosis and inflammation. Therefore, targeting GalR1 and GalR2 may be a novel therapeutic option for the treatment of NAFLD.

The protective effects of estrogen on biliary and liver damage are independent of ER‐β signaling in female Mdr2‐/‐ mice

BACKGROUND &amp; AIMCholestatic liver diseases present with ductular reaction, biliary senescence, peribiliary inflammation and bridging fibrosis, and sex‐dependent differences in liver injury exist in different pathologies. The multidrug resistance 2 knockout (Mdr2‐/‐) mouse is a model of toxic bile‐induced cholangitis which show a higher degree of injury in female mice. Estrogen signals through its receptors, ER‐α and ER‐β, that form homodimers and act as transcription factors. Interestingly, ER‐α and ER‐β can have differing downstream responses. In a model of autoimmune cholestasis, inhibition of ER‐β reduces biliary damage, inflammation, immune cell infiltration and liver fibrosis in both male and female mice. We aimed to determine the role of estrogen/ER‐β signaling on biliary and liver damage in female Mdr2‐/‐ mice.METHODSStudies were performed in female wild‐type (WT) and Mdr2‐/‐ mice at 12 wks of age, with a subset of Mdr2‐/‐ mice subjected to ovariectomy (OVX, to reduce estrogen levels) or treated with PHTPP (ER‐β antagonist, 15 mg/kg BW/day by I.P. implanted minipump) for 1 wk. All studies utilized n=4 mice per group. We evaluated liver damage by H&amp;E staining. Ductular reaction was measured by CK‐19 staining and semi‐quantification, and biliary senescence was imaged using p16 co‐staining with CK‐19 (to mark bile ducts). Peribiliary inflammation was evaluated using F4/80 (macrophage marker) staining and semi‐quantification, and qPCR for IL‐6 and TNF‐α in total liver samples. Immune cell infiltration was visualized by staining for CD3 (pan‐T cell marker) and CD20 (pan‐B cell marker). We determined liver fibrosis by (i) Sirius red staining and semi‐quantification, (ii) qPCR for TIMP1, Col1a1 and αSMA in total liver samples and (iii) co‐staining for desmin (hepatic stellate cell marker) with CK‐19. Human female control (avg. age 24.5 yr) and late‐stage, untreated PSC patient (avg. age 51.8 yr) serum samples were evaluated for estrogen levels by EIA.RESULTSOVX exacerbated liver damage, ductular reaction, biliary senescence, inflammation, immune response and liver fibrosis in female Mdr2‐/‐ mice, demonstrating a protective effect of estrogen signaling during cholangitis. Interestingly, female Mdr2‐/‐ mice treated with PHTPP (blocks ER‐β activity) had no change in any parameters of biliary damage or liver injury when compared to controls suggesting that estrogen’s protective effects are not mediated through ER‐β. Serum estrogen levels increased in female PSC samples versus control, potentially as a compensatory response or abnormal dysregulation as a consequence of injury.CONCLUSIONEstrogen may have a protective effect against biliary damage, inflammation, immune response and liver fibrosis during cholestasis. However, the protective effects are not dependent upon ER‐β signaling in female Mdr2‐/‐ mice and future work is ongoing to understand the role or ER‐α in this setting. Alteration of specific estrogen signaling mechanisms may be important for targeting cholestatic liver diseases in female patients.

C-X-C motif chemokine ligand 1 induced by Hedgehog signaling promotes mouse extrahepatic bile duct repair after acute injury.

In extrahepatic bile duct (EHBD) cholangiopathies, including primary sclerosing cholangitis, a reactive cholangiocyte phenotype is associated with inflammation and epithelial hyperproliferation. The signaling pathways involved in EHBD injury response are poorly understood. In this study, we investigated the role of Hedgehog (HH) signaling and its downstream effectors in controlling biliary proliferation and inflammation after EHBD injury. Using mouse bile duct ligation as an acute EHBD injury model, we used inhibitory paradigms to uncover mechanisms promoting the proliferative response. HH signaling was inhibited genetically in Gli1-/- mice or by treating wild-type mice with LDE225. The role of neutrophils was tested using chemical (SB225002) and biological (lymphocyte antigen 6 complex locus G6D [Ly6G] antibodies) inhibitors of neutrophil recruitment. The cellular response was defined through morphometric quantification of proliferating cells and CD45+ and Ly6G+ immune cell populations. Key signaling component expression was measured and localized to specific EHBD cellular compartments by in situ hybridization, reporter strain analysis, and immunohistochemistry. Epithelial cell proliferation peaked 24 h after EHBD injury, preceded stromal cell proliferation, and was associated with neutrophil influx. Indian HH ligand expression in the biliary epithelium rapidly increased after injury. HH-responding cells and neutrophil chemoattractant C-X-C motif chemokine ligand 1 (CXCL1) expression mapped to EHBD stromal cells. Inhibition of HH signaling blocked CXCL1 induction, diminishing neutrophil recruitment and the biliary proliferative response to injury. Directly targeting neutrophils by inhibition of the CXCL1/C-X-C motif chemokine receptor 2/Ly6G signaling axis also decreased biliary proliferation. HH-regulated CXCL1 orchestrates the early inflammatory response and biliary proliferation after EHBD injury through complex cellular crosstalk.

Bile acid-sensitive tuft cells regulate biliary neutrophil influx.

Inflammation and dysfunction of the extrahepatic biliary tree are common causes of human pathology, including gallstones and cholangiocarcinoma. Despite this, we know little about the local regulation of biliary inflammation. Tuft cells, rare sensory epithelial cells, are particularly prevalent in the mucosa of the gallbladder and extrahepatic bile ducts. Here, we show that biliary tuft cells express a core genetic tuft cell program in addition to a tissue-specific gene signature and, in contrast to small intestinal tuft cells, decreased postnatally, coincident with maturation of bile acid production. Manipulation of enterohepatic bile acid recirculation revealed that tuft cell abundance is negatively regulated by bile acids, including in a model of obstructive cholestasis in which inflammatory infiltration of the biliary tree correlated with loss of tuft cells. Unexpectedly, tuft cell-deficient mice spontaneously displayed an increased gallbladder epithelial inflammatory gene signature accompanied by neutrophil infiltration that was modulated by the microbiome. We propose that biliary tuft cells function as bile acid-sensitive negative regulators of inflammation in biliary tissues and serve to limit inflammation under homeostatic conditions.

Faecal calprotectin is a surrogate marker of biliary inflammation in primary sclerosing cholangitis associated inflammatory bowel disease

ObjectiveFaecal calprotectin (fCAL) is an established marker of intestinal inflammation in inflammatory bowel disease (IBD). Disproportionally high fCAL levels, for the severity of intestinal inflammation, have been previously observed in...

The Result of the Critical View of Safety Timeout Technique in Prevention of Bile Duct Injury in Laparoscopic Cholecystectomy: A Retrospective Study at a Large Community Teaching Hospital

Background: Laparoscopic cholecystectomy (LC) is the standard treatment for cholelithiasis. However, despite improvements in technology and implementation of a safer approach, such as the critical view of safety (CVS) technique, the risk of bile duct injury (BDI) remains an issue. Objective: To review LC cases at a large community hospital for BDIs and compare BDI rates between conventional technique and CVS timeout approaches. The authors hypothesized that there would be lower BDI rates in the CVS timeout group. Materials and Methods: The authors conducted a retrospective study of 1,033 consecutive patients that underwent LC at the authors’ institution between November 2015 and November 2018. Based on the timeout document and operative reports, the authors classified patients into CVS timeout and no CVS (noCVS) timeout groups and compared the BDI rates and other relevant clinical outcomes. Results: Among the 1,033 patients, 635 and 398 patients were in the noCVS timeout and CVS timeout groups, respectively. There was no significant difference in the incidence of BDI between the two groups at 1.1% versus 1.8%, respectively (p=0.375). The CVS group exhibited less preemptive conversion to open cholecystectomy, lower incidence of uncontrolled intraoperative bleeding, shorter operative time, and shorter length of hospital stay than the noCVS group. In multivariate regression analysis, operative time of more than 90 minutes was the significant independent risk factor associated with BDI, while previous biliary inflammation was marginally associated with BDI. Conclusion: The present study failed to demonstrate the beneficial effect of CVS timeout in preventing the development of BDI. The reasons could be attributed to surgeons’ competency with their varying skills and experience, the occurrence of injury before timeout, the case selection biases, or the wrong CVS identification. Further review of the actual surgical videos may offer more clarity into the unexpected outcome. Keywords: Bile duct injuries; Critical view of safety; Infundibular techniques; Laparoscopic cholecystectomy