IL-17 signaling in primary sclerosing cholangitis patient-derived organoids.

BACKGROUND: The pathogenesis of primary sclerosing cholangitis (PSC) is unclear, although studies implicate IL-17A as an inflammatory mediator in this disease. However, a direct assessment of IL-17 signaling in PSC cholangiocytes is lacking. In this study, we aimed to investigate and characterize the response of PSC extrahepatic cholangiocyte organoids (ECO) to IL-17A stimulation. METHODS: Cholangiocytes obtained from patients with PSC and without PSC by endoscopic retrograde cholangiography were cultured as ECO. The ECO were treated with vehicle or IL-17A and assessed by transcriptomics, secretome analysis, and genome sequencing. RESULTS: Unsupervised clustering of all integrated single-cell RNA sequencing data identified 8 cholangiocyte clusters that did not differ between PSC and non-PSC ECO. However, PSC ECO cells demonstrated a robust response to IL-17 treatment, as noted by an increased number of differentially expressed genes by transcriptomics and more abundant chemokine and cytokine expression and secretion. After rigorous filtering, genome sequencing identified candidate somatic variants shared among PSC ECO from unrelated individuals. However, no candidate rare variants in genes regulating the IL-17 pathway were identified, but rare variants regulating the MAPK signaling pathway were present in all PSC ECO. CONCLUSIONS: PSC and non-PSC patient-derived ECO respond differently to IL-17 stimulation, implicating this pathway in the pathogenesis of PSC.

Coexistence of metabolic-associated fatty liver disease and autoimmune or toxic liver disease.

Fatty liver disease (FLD) affects approximately 25% of global adult population. Metabolic-associated fatty liver disease (MAFLD) is a term used to emphasize components of metabolic syndrome in FLD. MAFLD does not exclude coexistence of other liver disease, but impact of coexisting MAFLD is unclear. We investigated prevalence and characteristics of MAFLD in patients with biopsy-proven autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), or toxic liver disease. Liver histopathology and clinical data from Helsinki University Hospital district (1.7 million inhabitants) between 2009 and 2019 were collected from patients with AIH, PBC, PSC, or toxic liver disease at the time of diagnosis. MAFLD was diagnosed as macrovesicular steatosis ≥5% together with obesity, type-2 diabetes, or signs of metabolic dysregulation. Of 648 patients included, steatosis was observed in 15.6% (n = 101), of which 94.1% (n = 95) was due to MAFLD. Prevalence of coexisting MAFLD in the four liver diseases varied between 12.4 and 18.2% (P = 0.483). Fibrosis was more severe in MAFLD among patients with toxic liver disease (P = 0.01). Histopathological characteristics otherwise showed similar distribution among MAFLD and non-FLD controls. Alcohol consumption was higher in MAFLD group among patients with AIH or PBC (P < 0.05 for both). In AIH, smoking was more common in patients with coexisting MAFLD (P = 0.034). Prevalence of coexisting MAFLD in other primary liver diseases is lower than reported in general population. Histopathology of MAFLD patients did not clearly differ from non-FLD ones. Alcohol and smoking were associated with MAFLD in AIH.

Patient-focused drug development in primary sclerosing cholangitis: Insights on patient priorities and involvement in clinical trials.

BACKGROUND: According to the new AASLD Practice Guidance, all patients with primary sclerosing cholangitis (PSC) should be considered for participation in clinical trials. However, PSC's rarity has posed challenges to characterizing patient interest in trial participation and identifying predictors of patient willingness to participate in drug trials. METHODS: PSC Partners Seeking a Cure developed the "Our Voices" survey to inform the development of the Externally-Led Patient-Focused Drug Development Forum, an FDA initiative to capture patient experiences and perspectives on drug development. RESULTS: Of 797 survey respondents from over 30 countries, 536 (67%) identified slowing disease progression as the most important outcome. Eighty-nine percent identified their hepatologist/gastroenterologist as someone they would approach for advice about trials. Although 61% reported being willing to participate in drug trials, only 26% had ever been asked to participate. Notable barriers to trial involvement included unknown long-term risks (71%), long travel times to the study center (32%), and a liver biopsy requirement (27%). On multivariable logistic regression, pruritus (OR 1.62, 95% CI: 1.09-2.40, p = 0.017) was positively associated with willingness to participate in disease-modifying therapy trials, while jaundice (OR 0.34, 95% CI: 0.19-0.61, p < 0.001) and inflammatory bowel disease (OR 0.64, 95% CI: 0.42-0.98, p = 0.038) were negatively associated. Pruritus (OR 2.25, 95% CI: 1.50-3.39, p < 0.001) was also independently associated with willingness to participate in symptom treatment trials. CONCLUSIONS: Most patients with PSC report interest in participating in clinical trials, but few have been asked to participate. Referral of patients with PSC by their hepatologist/gastroenterologist to clinical trials and patient education on trial participation are vital to closing the gap between trial interest and participation. Pruritus may serve as a key indicator of patient interest in trial participation.

Surveillance MRI is associated with improved survival in patients with primary sclerosing cholangitis.

BACKGROUND: The benefits of regular surveillance imaging for cholangiocarcinoma in patients with primary sclerosing cholangitis (PSC) are unclear. Hence, we aimed to evaluate the impact of regular magnetic resonance cholangiopancreatography (MRCP) on outcomes of patients with PSC in Australia, where the practice of MRCP surveillance is variable. METHODS: The relationship between MRCP surveillance and survival outcomes was assessed in a multicenter, retrospective cohort of patients with PSC from 9 tertiary liver centers in Australia. An inverse probability of treatment weighting approach was used to balance groups across potentially confounding covariates. RESULTS: A total of 298 patients with PSC with 2117 person-years of follow-up were included. Two hundred and twenty patients (73.8%) had undergone MRCP surveillance. Regular surveillance was associated with a 71% reduced risk of death on multivariate weighted Cox analysis (HR: 0.29, 95% CI: 0.14-0.59, p < 0.001) and increased likelihood of having earlier endoscopic retrograde cholangiopancreatography from the date of PSC diagnosis in patients with a dominant stricture (p < 0.001). However, survival posthepatobiliary cancer diagnosis was not significantly different between both groups (p = 0.74). Patients who had surveillance of less than 1 scan a year (n = 41) had comparable survival (HR: 0.46, 95% CI 0.16-1.35, p = 0.16) compared to patients who had surveillance at least yearly (n = 172). CONCLUSIONS: In this multicenter cohort study that employed inverse probability of treatment weighting to minimize selection bias, regular MRCP was associated with improved overall survival in patients with PSC; however, there was no difference in survival after hepatobiliary cancer diagnosis. Further prospective studies are needed to confirm the benefits of regular MRCP and optimal imaging interval in patients with PSC.

Unique bile acid profiles in the bile ducts of patients with primary sclerosing cholangitis.

BACKGROUND: The relationship between primary sclerosing cholangitis (PSC) and biliary bile acids (BAs) remains unclear. Although a few studies have compared PSC biliary BAs with other diseases, they did not exclude the influence of cholestasis, which affects the composition of BAs. We compared biliary BAs and microbiota among patients with PSC, controls without cholestasis, and controls with cholestasis, based on the hypothesis that alterations in BAs underlie the pathophysiology of PSC. METHODS: Bile samples were obtained using endoscopic retrograde cholangiopancreatography from patients with PSC (n = 14), non-hepato-pancreato-biliary patients without cholestasis (n = 15), and patients with cholestasis (n = 13). RESULTS: The BA profiles showed that patients with PSC and cholestasis controls had significantly lower secondary BAs than non-cholestasis controls, as expected, whereas the ratio of cholic acid/chenodeoxycholic acid in patients with PSC was significantly lower despite cholestasis, and the ratio of (cholic acid + deoxycholic acid)/(chenodeoxycholic acid + lithocholic acid) in patients with PSC was significantly lower than that in the controls with or without cholestasis. The BA ratio in the bile of patients with PSC showed a similar trend in the serum. Moreover, there were correlations between the alteration of BAs and clinical data that differed from those of the cholestasis controls. Biliary microbiota did not differ among the groups. CONCLUSIONS: Patients with PSC showed characteristic biliary and serum BA compositions that were different from those in other groups. These findings suggest that the BA synthesis system in patients with PSC differs from that in controls and patients with other cholestatic diseases. Our approach to assessing BAs provides insights into the pathophysiology of PSC.

Association between inflammatory bowel disease and primary sclerosing cholangitis: Insights from bibliometric analysis.

BACKGROUND: Crohn's disease and ulcerative colitis are forms of inflammatory bowel disease affecting approximately 1% of the population. Their typical features include chronic diarrhea, abdominal pain, and weight loss. Extraintestinal manifestations may coincide with or precede the diagnosis of these diseases. Primary sclerosing cholangitis is one such extraintestinal manifestation. Although many papers on this field have been published, bibliometric analysis still needs to be conducted. This article summarizes the current research progress through a bibliometric study, provides an overview of the research status in this field, and analyzes recent research trends. METHODS: Publications on inflammatory bowel disease and primary sclerosing cholangitis from January 1, 2008, to August 31, 2023, were extracted from the Web of Science Core Collection. VOSviewer and CiteSpace were used to perform a bibliometric and visual study. RESULTS: There are 1499 relevant articles, and the number of articles in this field has been relatively stable in recent years. The results indicate that Karlson TH from the University of Oslo has the highest cumulative number of publications. The institution with the highest publication output is the Mayo Clinic, and the United States leads in article production, occupying a dominant position. Keyword analysis reveals 4079 keywords, with primary sclerosing cholangitis, inflammatory bowel disease, and ulcerative colitis being the most frequently occurring keywords. CONCLUSION: Research on the association between inflammatory bowel disease and primary sclerosing cholangitis is steadily advancing, with the United States leading in publication output globally. China needs to invest more in research in this area, and collaboration among institutions should be strengthened. The research hotspots revolve around the association between inflammatory bowel disease and primary sclerosing cholangitis, gut microbiota, and other fields.

Genetically predicted gut microbiota mediate the association between plasma lipidomics and primary sclerosing cholangitis.

BACKGROUND: Primary sclerosing cholangitis (PSC) is a complex disease with pathogenic mechanisms that remain to be elucidated. Previous observational studies with small sample sizes have reported associations between PSC, dyslipidemia, and gut microbiota dysbiosis. However, the causality of these associations is uncertain, and there has been no systematic analysis to date. METHODS: The datasets comprise data on PSC, 179 lipid species, and 412 gut microbiota species. PSC data (n = 14,890) were sourced from the International PSC Study Group, while the dataset pertaining to plasma lipidomics originated from a study involving 7174 Finnish individuals. Data on gut microbiota species were derived from the Dutch Microbiome Project study, which conducted a genome-wide association study involving 7738 participants. Furthermore, we employed a two-step Mendelian randomization (MR) analysis to quantify the proportion of the effect of gut microbiota-mediated lipidomics on PSC. RESULTS: Following a rigorous screening process, our MR analysis revealed a causal relationship between higher levels of gene-predicted Phosphatidylcholine (O-16:1_18:1) (PC O-16:1_18:1) and an increased risk of developing PSC (inverse variance-weighted method, odds ratio (OR) 1.30, 95% confidence interval (CI) 1.03-1.63). There is insufficient evidence to suggest that gene-predicted PSC impacts the levels of PC O-16:1_18:1 (OR 1.01, 95% CI 0.98-1.05). When incorporating gut microbiota data into the analysis, we found that Eubacterium rectale-mediated genetic prediction explains 17.59% of the variance in PC O-16:1_18:1 levels. CONCLUSION: Our study revealed a causal association between PC O-16:1_18:1 levels and PSC, with a minor portion of the effect mediated by Eubacterium rectale. This study aims to further explore the pathogenesis of PSC and identify promising therapeutic targets. For patients with PSC who lack effective treatment options, the results are encouraging.

Serum Galectin-3 as a Non-Invasive Marker for Primary Sclerosing Cholangitis.

Primary sclerosing cholangitis (PSC) is a serious liver disease associated with inflammatory bowel disease (IBD). Galectin-3, an inflammatory and fibrotic molecule, has elevated circulating levels in patients with chronic liver disease and inflammatory bowel disease (IBD). This study aims to clarify whether galectin-3 can differentiate between patients with IBD, PSC, and PSC-IBD. Our study measured serum galectin-3 levels in 38 healthy controls, 55 patients with IBD, and 22 patients with PSC (11 patients had underlying IBD and 11 patients did not), alongside the urinary galectin-3 of these patients and 18 controls. Serum and urinary galectin-3 levels in IBD patients were comparable to those in controls. Among IBD patients, those with high fecal calprotectin, indicating severe disease, exhibited lower serum and elevated urinary galectin-3 levels compared to those with low calprotectin levels. Serum galectin-3 levels were inversely correlated with C-reactive protein levels. PSC patients displayed higher serum and urinary galectin-3 levels than IBD patients, with the highest serum levels observed in PSC patients with coexisting IBD. There was no correlation between serum and urinary galectin-3 levels and laboratory indicators of liver injury in both IBD and PSC patients. In conclusion, this study demonstrates that serum and urinary galectin-3 levels can distinguish IBD from PSC patients, and also reveals higher serum galectin-3 levels in PSC-IBD patients compared to those with isolated PSC.

Association between autoimmune liver diseases and chronic hepatitis B: A multivariable Mendelian randomization study in European population.

BACKGROUND: Observational studies have indicated a link between autoimmune liver diseases (AILD) and chronic hepatitis B (CHB) through observational studies. The association between AILD and CHB remains indeterminate. METHODS: A two-sample Mendelian randomization (MR) analysis was conducted to scrutinize the causal nexus between AILD and CHB utilizing summary statistics derived from extensive genome-wide association studies (GWASs) in European populations. The primary statistical methodology employed was the inverse variance-weighted (IVW) method to deduce the causal connection of AILD on CHB. This study incorporated primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and autoimmune hepatitis (AIH) as subtypes of AILD. Additionally, we conducted a multivariable MR (MVMR) analysis to account for the potential confounding effects of smoking, alcohol consumption, body mass index (BMI), and some autoimmune diseases. RESULTS: Our MR investigation encompassed a cohort of 725,816 individuals. The MR analysis revealed that genetically predicted PSC significantly correlated with a reduced risk of CHB (IVW OR = 0.857; 95%CI: 0.770-0.953, P = 0.005). Conversely, the reverse MR analysis suggested that genetic susceptibility to PSC might not modify the risk of CHB (IVW OR = 1.004; 95% CI: 0.958-1.053, P = 0.866). Genetically proxied PBC and AIH exhibited no discernible causal association with CHB in the MR analysis using the IVW method (P = 0.583; P = 0.425). The MVMR analysis still indicated a decreased risk of CHB associated with PSC (OR = 0.853, P = 0.003). CONCLUSION: Our study elucidates a causal relationship between PSC and a diminished risk of CHB.

Leveraging pQTL-based Mendelian randomization to identify new treatment prospects for primary biliary cholangitis and primary sclerosing cholangitis.

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are autoimmune disorders characterized by progressive and chronic damage to the bile ducts, presenting clinicians with significant challenges. The objective of this study is to identify potential druggable targets to offer new avenues for treatment. A Mendelian randomization analysis was performed to identify druggable targets for PBC and PSC. This involved obtaining Cis-protein quantitative trait loci (Cis-pQTL) data from the deCODE database to serve as exposure. Outcome data for PBC (557 cases and 281,127 controls) and PSC (1,715 cases and 330,903 controls) were obtained from the FINNGEN database. Colocalization analysis was conducted to determine whether these features share the same associated SNPs. Validation of the expression level of druggable targets was done using the GSE119600 dataset and immunohistochemistry for clinical samples. Lastly, the DRUGBANK database was used to predict potential drugs. The MR analysis identified eight druggable targets each for PBC and PSC. Subsequent summary-data-based MR and colocalization analyses showed that LEFTY2 had strong evidence as a therapeutic candidate for PBC, while HSPB1 had moderate evidence. For PSC, only FCGR3B showed strong evidence as a therapeutic candidate. Additionally, upregulated expression of these genes was validated in PBC and PSC groups by GEO dataset and clinical samples. This study identifies two novel druggable targets with strong evidence for therapeutic candidates for PBC (LEFTY2 and HSPB1) and one for PSC (FCGR3B). These targets offer new therapeutic opportunities to address the challenging nature of PBC and PSC treatment.

Intestinal microbiota and biliary system diseases.

Introduction: The incidence of biliary system diseases has been continuously increasing in the past decade. Biliary system diseases bring a heavy burden to humanity and society. However, the specific etiology and pathogenesis are still unknown. The biliary system, as a bridge between the liver and intestine, plays an indispensable role in maintaining the physiological metabolism of the body. Therefore, prevention and treatment of biliary diseases are crucial. It is worth noting that the microorganisms participate in the lipid metabolism of the bile duct, especially the largest proportion of intestinal bacteria. Methods: We systematically reviewed the intestinal microbiota in patients with gallstones (GS), non-calculous biliary inflammatory, and biliary tract cancer (BTC). And searched Pubmed, Embase and Web of science for research studies published up to November 2023. Results: We found that the abundance of Faecalibacterium genus is decreased in GS, primary sclerosing cholangitis (PSC), primary biliary cholangitis (PBC) and BTC. Veillonella, Lactobacillus, Streptococcus and Enterococcus genus were significantly increased in PSC, PBC and BTC. Interestingly, we found that the relative abundance of Clostridium was generally reduced in GS, PBC and BTC. However, Clostridium was generally increased in PSC. Discussion: The existing research mostly focuses on exploring the mechanisms of bacteria targeting a single disease. Lacking comparison of multiple diseases and changes in bacteria during the disease process. We hope to provide biomarkers forearly diagnosis of biliary system diseases and provide new directions for the mechanism of intestinal microbiota in biliary diseases.

STAT activation in regulatory CD4+ T cells of patients with primary sclerosing cholangitis.

INTRODUCTION: Regulatory CD4+ T cells (Tregs) are pivotal for inhibition of autoimmunity. Primary sclerosing cholangitis (PSC) is an autoimmune cholestatic liver disease of unknown etiology where contribution of Tregs is still unclear. Activation of the JAK-STAT pathway critically modifies functions of Tregs. In PSC, we studied activation of STAT proteins and Treg functions in response to cytokines. METHODS: In 51 patients with PSC, 10 disease controls (chronic replicative hepatitis C), and 36 healthy controls we analyzed frequencies of Foxp3+CD25+CD127lowCD4+ Tregs, their expression of ectonucleotidase CD39, and cytokine-induced phosphorylation of STAT1, 3, 5, and 6 using phospho-flow cytometry. In parallel, we measured cytokines IFN-gamma, interleukin (IL)-6, IL-2, and IL-4 in serum via bead-based immunoassays. RESULTS: In patients with PSC, ex vivo frequencies of peripheral Tregs and their expression of CD39 were significantly reduced (p < .05 each). Furthermore, serum levels of IFN-gamma, IL-6, IL-2, and IL-4 were markedly higher in PSC (p < .05 each). Unlike activation of STAT1, STAT5, and STAT6, IL-6 induced increased phosphorylation of STAT3 in Tregs of PSC-patients (p = .0434). Finally, STAT3 activation in Tregs correlated with leukocyte counts. CONCLUSIONS: In PSC, we observed enhanced STAT3 responsiveness of CD4+ Tregs together with reduced CD39 expression probably reflecting inflammatory activity of the disease.

The casual relationship between autoimmune diseases and multiple myeloma: a Mendelian randomization study.

Observational studies showed possible associations between systemic lupus erythematosus and multiple myeloma. However, whether there is a casual relationship between different types of autoimmune diseases (type 1 diabetes mellitus, rheumatoid arthritis, systemic lupus erythematosus, psoriasis, multiple sclerosis, primary sclerosing cholangitis, primary biliary cirrhosis, and juvenile idiopathic arthritis) and multiple myeloma (MM) is not well known. We performed a two-sample Mendelian randomization (MR) study to estimate the casual relationship. Summary-level data of autoimmune diseases were gained from published genome-wide association studies while data of MM was obtained from UKBiobank. The Inverse-Variance Weighted (IVW) method was used as the primary analysis method to interpret the study results, with MR-Egger and weighted median as complementary methods of analysis. There is causal relationship between primary sclerosing cholangitis [OR = 1.00015, 95% CI 1.000048-1.000254, P = 0.004] and MM. Nevertheless, no similar causal relationship was found between the remaining seven autoimmune diseases and MM. Considering the important role of age at recruitment and body mass index (BMI) in MM, we excluded these relevant instrument variables, and similar results were obtained. The accuracy and robustness of these findings were confirmed by sensitivity tests. Overall, MR analysis suggests that genetic liability to primary sclerosing cholangitis could be causally related to the increasing risk of MM. This finding may serve as a guide for clinical attention to patients with autoimmune diseases and their early screening for MM.

Epidemiology of autoimmune liver disease in Korea: evidence from a nationwide real-world database.

BACKGROUND: Autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) are all immune-mediated chronic inflammatory liver diseases. Autoimmune liver diseases are rare, making identification and treatment difficult. To improve clinical outcomes and enhance patient quality of life, we performed an epidemiological study of autoimmune liver diseases based on real-world comprehensive data. RESULTS: We used National Health Insurance Service claims data in Korea from 2005 to 2019. Patients were identified using the International Classification of Disease 10th Revision code, and rare intractable disease codes assigned according to the strict diagnostic criteria. In the AIH cohort, 8,572 (83.9%) were females and the mean age at diagnosis was 56.3 ± 14.3 years. PBC also showed female dominance (83.3%) and the mean age was 57.8 ± 12.6 years. Patients with PSC showed no sex predominance and had a mean age of 57.8 ± 21.5 years. During the study period, there were 10,212, 6,784, and 888 AIH, PBC, and PSC patients, respectively. The prevalence of AIH, PBC, and PSC in 2019 were 18.4, 11.8, and 1.5 per 100,000 population, while the corresponding incidences were 2.3, 1.4, and 0.3 per 100,000 population, respectively. Analysis of sex-age-standardized data showed that the annual prevalence of these diseases is increasing. The 10-year survival rates were 89.8%, 74.9%, and 73.4% for AIH, PBC, and PSC, respectively. CONCLUSIONS: The number of patients with autoimmune liver disease in South Korea is increasing over time. Further research on autoimmune liver disease is needed to fulfill unmet clinical needs.

Imaging-based diagnosis of sarcopenia for transplant-free survival in primary sclerosing cholangitis.

BACKGROUND: Imaging-based assessment of sarcopenia is a well-validated prognostic tool for patients with chronic liver disease. However, little is known about its value in patients with primary sclerosing cholangitis (PSC). This cross-sectional study aimed to investigate the predictive value of the cross-sectional imaging-based skeletal muscle index (SMI) for transplant-free survival (TFS) in patients with PSC. METHODS: A total of 95 patients with PSC who underwent abdominal cross-sectional imaging between 2008 and 2022 were included in this retrospective study. SMI was measured at the third lumbar vertebra level (L3-SMI). The cut-off values to define sarcopenia were < 50 cm²/m² in male patients and < 39 cm²/m² in female patients. The primary outcome of this study was TFS, which was defined as survival without liver transplantation or death from any cause. RESULTS: Our study indicates that L3-SMI sarcopenia impairs TFS in patients with PSC (5-year TFS: 33.9% vs. 83.3%, p = 0.001, log-rank test). L3-SMI sarcopenia was independently associated with reduced TFS via multivariate Cox regression analysis (HR = 2.749; p = 0.028). Body mass index reduction > 10% at 12 months, which is used as MELD standard exception (SE) criterion in Eurotransplant (in Germany only until September 2023), was not significantly associated with TFS in the multivariate Cox regression analysis (HR = 1.417; p = 0.330). Substitution of BMI reduction with L3-SMI in the German SE criteria improved the predictive accuracy of TFS compared to the established SE criteria (multivariable Cox regression analysis: HR = 4.007, p < 0.001 vs. HR = 1.691, p = 0.141). CONCLUSION: Imaging-based diagnosis of sarcopenia via L3-SMI is associated with a low TFS in patients with PSC and may provide additional benefits as a prognostic factor in patient selection for liver transplantation.

Periportal macrophages protect against commensal-driven liver inflammation.

The liver is the main gateway from the gut, and the unidirectional sinusoidal flow from portal to central veins constitutes heterogenous zones, including the periportal vein (PV) and the pericentral vein zones1-5. However, functional differences in the immune system in each zone remain poorly understood. Here intravital imaging revealed that inflammatory responses are suppressed in PV zones. Zone-specific single-cell transcriptomics detected a subset of immunosuppressive macrophages enriched in PV zones that express high levels of interleukin-10 and Marco, a scavenger receptor that sequesters pro-inflammatory pathogen-associated molecular patterns and damage-associated molecular patterns, and consequently suppress immune responses. Induction of Marco+ immunosuppressive macrophages depended on gut microbiota. In particular, a specific bacterial family, Odoribacteraceae, was identified to induce this macrophage subset through its postbiotic isoallolithocholic acid. Intestinal barrier leakage resulted in inflammation in PV zones, which was markedly augmented in Marco-deficient conditions. Chronic liver inflammatory diseases such as primary sclerosing cholangitis (PSC) and non-alcoholic steatohepatitis (NASH) showed decreased numbers of Marco+ macrophages. Functional ablation of Marco+ macrophages led to PSC-like inflammatory phenotypes related to colitis and exacerbated steatosis in NASH in animal experimental models. Collectively, commensal bacteria induce Marco+ immunosuppressive macrophages, which consequently limit excessive inflammation at the gateway of the liver. Failure of this self-limiting system promotes hepatic inflammatory disorders such as PSC and NASH.

Vascular adhesion protein-1 blockade in primary sclerosing cholangitis: Open-label, multicenter, single-arm, phase II trial.

BACKGROUND: Primary sclerosing cholangitis is a progressive inflammatory liver disease characterized by biliary and liver fibrosis. Vascular adhesion protein-1 (VAP-1) is important in the inflammatory process driving liver fibrosis. We evaluated the safety and efficacy of VAP-1 blockade with a monoclonal antibody (timolumab, BTT1023) in patients with primary sclerosing cholangitis. METHODS: BUTEO was a prospective, single-arm, open-label, multicenter, phase II trial, conducted in 6 centers in the United Kingdom. Patients with primary sclerosing cholangitis aged 18-75 years had an alkaline phosphatase value of >1.5 times the upper limit of normal. The dose-confirmatory stage aimed to confirm the safety of timolumab through the incidence of dose-limiting toxicity and sufficient trough levels of circulating antibody to block VAP-1 function. The primary outcome of the dose-expansion portion of the trial was patient's response to timolumab at day 99, as measured by a reduction in serum alkaline phosphatase by 25% or more from baseline to day 99. RESULTS: Twenty-three patients were recruited: 7 into the initial dose-confirmatory stage and a further 16 into an expansion stage. Timolumab (8 mg/kg) was confirmed to be safe for the duration of administration with sufficient circulating levels. Only 2 of the 18 evaluable patients (11.1%) achieved a reduction in alkaline phosphatase levels of 25% or more, and both the proportion of circulating inflammatory cell populations and biomarkers of fibrosis remained unchanged from baseline. CONCLUSIONS: The BUTEO trial confirmed 8 mg/kg timolumab had no short-term safety signals and resulted in sufficient circulating levels of VAP-1 blocking timolumab. However, the trial was stopped after an interim assessment due to a lack of efficacy as determined by no significant change in serum liver tests.