Single-cell RNA sequencing reveals the pro-inflammatory roles of liver-resident Th1-like cells in primary biliary cholangitis.

Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease characterized by multilineage immune dysregulation, which subsequently causes inflammation, fibrosis, and even cirrhosis of liver. Due to the limitation of traditional assays, the local hepatic immunopathogenesis of PBC has not been fully characterized. Here, we utilize single-cell RNA sequencing technology to depict the immune cell landscape and decipher the molecular mechanisms of PBC patients. We reveal that cholangiocytes and hepatic stellate cells are involved in liver inflammation and fibrosis. Moreover, Kupffer cells show increased levels of inflammatory factors and decreased scavenger function related genes, while T cells exhibit enhanced levels of inflammatory factors and reduced cytotoxicity related genes. Interestingly, we identify a liver-resident Th1-like population with JAK-STAT activation in the livers of both PBC patients and murine PBC model. Finally, blocking the JAK-STAT pathway alleviates the liver inflammation and eliminates the liver-resident Th1-like cells in the murine PBC model. In conclusion, our comprehensive single-cell transcriptome profiling expands the understanding of pathological mechanisms of PBC and provides potential targets for the treatment of PBC in patients.

Application of liver biopsy in etiological diagnosis of unexplained portal hypertension: Porto-sinusoidal vascular disease should not be ignored.

The diagnostic value of liver biopsy has been confirmed in patients with abnormal liver test results; however, little data are available on its application in patients with portal hypertension. This study aimed to investigate the utility of liver biopsy for the etiological diagnosis of unexplained portal hypertension, and explore the clinical and pathological characteristics of each etiology. A retrospective observational analysis was conducted on 1367 patients who underwent liver biopsy at the Second Hospital of Nanjing from 2017 to 2019. Of these, 188 patients with unexplained portal hypertension were enrolled. The clinical and pathological characteristics were collected and reassessed in a multidisciplinary team meeting. Among these patients, 174 (92.6%, 174/188) had a definite etiological diagnosis through liver biopsy. The main etiologies were autoimmune hepatitis in 47 patients (25%, 47/188), autoimmune hepatitis-primary biliary cirrhosis overlap syndrome in 41 patients (21.8%, 41/188), and porto-sinusoidal vascular disease (PSVD) in 40 patients (21.3%, 40/188). Compared to liver cirrhosis, PSVD patients were younger and the liver function damage of which was subtler. The widths of portal vein diameter were widest in PSVD but the liver stiffness measurement were almost normal. Splenomegaly was common in PSVD, but ascites were less frequent than in autoimmune hepatitis (25.0% vs 51.1%, P = .013). Based on the histological patterns, we found that cholestatic liver diseases such as primary biliary cirrhosis, autoimmune hepatitis-primary biliary cirrhosis overlap syndrome, and progressive familial intrahepatic cholestasis could lead to non-cirrhotic portal hypertension, while vascular liver diseases such as PSVD and Budd-Chiari syndrome could also show fibrous proliferation as the disease progresses. Liver biopsy is safe and valuable for etiological diagnosis of unexplained portal hypertension. Cirrhosis is the leading cause of portal hypertension, and porto-sinusoidal vascular diseases should also be considered. Clinical features may be helpful in suggesting the cause; however, pathological examination is still indispensable for disease diagnosis and progression assessment.

Current Landscape and Evolving Therapies for Primary Biliary Cholangitis.

Primary Biliary Cholangitis (PBC) is a chronic autoimmune liver disorder characterized by progressive cholestatic that, if untreated, can progress to liver fibrosis, cirrhosis and liver decompensation requiring liver transplant. Although the pathogenesis of the disease is multifactorial, there is a consensus that individuals with a genetic predisposition develop the disease in the presence of specific environmental triggers. A dysbiosis of intestinal microbiota is increasingly considered among the potential pathogenic factors. Cholangiocytes, the epithelial cells lining the bile ducts, are the main target of a dysregulated immune response, and cholangiocytes senescence has been recognized as a driving mechanism, leading to impaired bile duct function, in disease progression. Bile acids are also recognized as playing an important role, both in disease development and therapy. Thus, while bile acid-based therapies, specifically ursodeoxycholic acid and obeticholic acid, have been the cornerstone of therapy in PBC, novel therapeutic approaches have been developed in recent years. In this review, we will examine published and ongoing clinical trials in PBC, including the recently approved peroxisome-proliferator-activated receptor (PPAR) agonist, elafibranor and seladelpar. These novel second-line therapies are expected to improve therapy in PBC and the development of personalized approaches.

The fecal microbiota of patients with primary biliary cholangitis (PBC) causes PBC-like liver lesions in mice and exacerbates liver damage in a mouse model of PBC.

The role of the gut microbiota in the occurrence and progression of primary biliary cholangitis (PBC) is not fully understood. First, the fecal microbiota of patients with PBC (n = 4) (PBC-FMT) or healthy individuals (n = 3) (HC-FMT) was transplanted into pseudo germ-free mice or 2OA-BSA-induced PBC models. The functions, histology and transcriptome of the liver, and microbiota and metabolome of the feces were analyzed. Second, the liver transcriptomes of PBC patients (n = 7) and normal individuals (n = 7) were analyzed. Third, the liver transcriptomes of patients with other liver diseases were collected from online databases and compared with our human and mouse data. Our results showed that PBC-FMT increased the serum ALP concentration, total bile acid content, liver injury and number of disease-related pathways enriched with upregulated liver genes in pseudo germ-free mice and increased the serum glycylproline dipeptidyl aminopeptidase level and liver damage in a 2OA-BSA-induced PBC model. The gut microbiota and metabolome differed between PBC-FMT and HC-FMT mice and reflected those of their donors. PBC-FMT tended to upregulate hepatic immune and signal transduction pathways but downregulate metabolic pathways, as in some PBC patients. The hematopoietic cell lineage, Toll-like receptor, and PPAR signaling pathway were not affected in patients with alcoholic hepatitis, HBV, HCV, HCV cirrhosis, or NASH, indicating their potential roles in the gut microbiota affecting PBC. In conclusion, the altered gut microbiota of PBC patients plays an important role in the occurrence and progression of PBC. The improvement of the gut microbiota is worthy of in-depth research and promotion as a critical aspect of PBC prevention and treatment.

Dietary therapy of murine primary biliary cholangitis induces hepatocellular steatosis: A cautionary tale.

BACKGROUND AND AIMS: There is increased interest in utilizing dietary interventions to alter the progression of autoimmune diseases. These efforts are driven by associations of gut microbiota/metabolites with levels of short-chain fatty acids (SCFAs). Propionate is a key SCFA that is commonly used as a food preservative and is endogenously generated by bacterial fermentation of non-digestible carbohydrates in the gut. A thesis has suggested that a diet rich in propionate and other SCFAs can successfully modulate autoimmunity. Herein, we investigated the effect of long-term administration of propionylated high-amylose resistant starches (HAMSP) on the course of murine primary biliary cholangitis. MATERIALS AND METHODS: Groups of female ARE-Del mice were fed an HAMSP diet either before or after disease onset. A detailed immunobiological analysis was performed involving autoantibodies and rigorous T-cell phenotyping, including enumeration of T-cell subsets in the spleen, liver, intestinal intraepithelial lymphocytes and lamina propria by flow cytometry. Histopathological scores were used to assess the frequency and severity of liver inflammation and damage to hepatocytes and bile ducts. RESULTS: Our results demonstrate that a long-term propionate-yielding diet re-populated the T-cell pool with decreased naïve and central memory T-cell subsets and an increase in the effector memory T cells in mice. Similarly, long-term HAMSP intake reduced CD4+CD8+ double-positive T cells in intraepithelial lymphocytes and the intestinal lamina propria. Critically, HAMSP consumption led to moderate-to-severe hepatocellular steatosis in ARE-Del mice, independent of the stage of autoimmune cholangitis. CONCLUSIONS: Our data suggest that administration of HAMSP induces both regulatory and effector T cells. Furthermore, HAMSP administration resulted in hepatocellular steatosis. Given the interest in dietary modulation of autoimmunity and because propionate is widely used as a food preservative, these data have significant implications. This study also provides new insights into the immunological and pathological effects of chronic propionate exposure.

Diagnostic accuracy of vibration-controlled transient elastography for staging liver fibrosis in autoimmune liver diseases: A systematic review and meta-analysis.

BACKGROUND/AIMS: The assessment of liver fibrosis is crucial for managing autoimmune liver diseases such as primary biliary cholangitis (PBC), autoimmune hepatitis (AIH), and primary sclerosing cholangitis (PSC). However, data on the efficacy of noninvasive tests for these diseases are limited. This meta-analysis evaluated the diagnostic accuracy of vibration-controlled transient elastography (VCTE) for staging fibrosis in patients with autoimmune liver disease. METHODS: Searches were conducted in PubMed, Embase, CINAHL, Web of Science, and Cochrane Library databases to assess the diagnostic accuracy of VCTE against histology as the reference standard in adult patients with autoimmune liver disease. The summary area under the curve (sAUC) and diagnostic odds ratio were calculated for significant fibrosis (SF), advanced fibrosis (AF), and cirrhosis, according to liver biopsy. RESULTS: Fourteen articles were included, comprising 559 PBC patients from six studies, 388 AIH patients from five studies, and 151 PSC patients from three studies. VCTE demonstrated good performance for fibrosis staging in PBC, AIH, and PSC. In PBC, sAUCs of VCTE were 0.87, 0.89, and 0.99 for staging SF, AF, and cirrhosis, respectively. In AIH, the sAUCs were 0.88, 0.88, and 0.92, respectively, while in PSC, they were 0.88, 0.95, and 0.92, respectively. The cutoff values for AF were 7.5-17.9 kPa in PBC, 8.18-12.1 kPa in AIH, and 9.6 kPa in PSC. CONCLUSION: VCTE shows high diagnostic accuracy for staging liver fibrosis in patients with autoimmune liver diseases. This non-invasive method serves as a valuable tool for the evaluation and monitoring of fibrosis in these lifelong diseases.

The relationship between CXCR6+CD8+T cells and clinicopathological parameters in patients with primary biliary cholangitis.

BACKGROUND: CXCR6+CD8+T cells have been implicated in the pathogenesis of various liver and autoimmune diseases. However, their involvement in primary biliary cholangitis (PBC) has not been elucidated. METHODS: We used immunohistochemistry and flow cytometry to quantify CXCR6+CD8+T cells in hepatic tissue and peripheral blood samples obtained from CXCR6+CD8+T cells obtained from PBC patients. Then, we performed comprehensive statistical analyses to access the correlation between the abundance of these cells and clinical as well as pathological data across different stages of PBC. RESULTS: Our research revealed that CXCR6+ cell frequencies in CD3+CD8+T cells from PBC patients significantly exceeded that of healthy controls (HCs) (2.24 vs. 0.61%, p < 0.01). A similar pattern emerged for hepatic CXCR6+CD8+T cell counts, which were notably higher in the PBC cohort compared to HCs. Our cohort consisted of 118 PBC patients, categorized into 62 early-stage (E-PBC) and 56 late-stage (L-PBC) cases. Notably, significant disparities existed between these groups in terms of liver enzyme and lipid profile levels (p < 0.05), with no notable differences observed in gender, age, blood counts, cholesterol levels, or autoantibodies (p > 0.05). Intriguingly, the quantity of hepatic CXCR6+CD8+T cells per high power field (HPF) was significantly elevated in both E-PBC and L-PBC patients as opposed to normal liver samples, indicating a substantial increase in these cells across all stages of PBC (p = 0.000). Spearman's rank correlation analysis showed a positive correlation between CXCR6+CD8+T cell counts and serum levels of Alkaline Phosphatase (AKP) and Gamma-Glutamyl Transferase (GGT), ANA, IgG and IgM, while revealing a negligible correlation with Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST). Subsequent findings indicated significant variances in CXCR6+ cell numbers not only among different PBC stages but also across various degrees of inflammation and fibrosis (p ≤ 0.007). In a follow-up study post-Ursodeoxycholic Acid (UDCA) treatment, stark differences were identified in biochemical and immunohistochemical profiles between responder (31 patients) and non-responder (33 patients) groups (p < 0.05). A Wilcoxon rank-sum test further demonstrated a significant difference in the level of hepatic CXCR6+CD8+T cells between these two response groups (p = 0.002). CONCLUSION: CXCR6+CD8+T cells play a vital role in the pathogenesis of PBC, exhibiting correlations with the extent of inflammation, staging of liver fibrosis, and response to pharmacological interventions in PBC patients.

Pre-treatment with tocilizumab reduces lipopolysaccharide-induced acute lung injury in biliary cirrhotic rats.

Infection-related lipopolysaccharide (LPS) release causes cytokine storm and acute lung injury. Emerging data show that the interleukin 6 (IL-6) inhibitor tocilizumab can improve lung damage in patients with sepsis. This study aimed to investigate the therapeutic effect of tocilizumab on acute lung injury in cirrhotic rats. Biliary cirrhosis was induced in Sprague-Dawley rats with common bile duct ligation (BDL). Sham-operated rats served as surgical controls. Tocilizumab was administered on post-operative day 21, and LPS was injected intraperitoneally on day 29. Three hours after LPS injection, hemodynamic parameters, biochemistry data, and arterial blood gas analysis were evaluated, along with measurements of IL-6 and tumor necrosis factor-α (TNF-α). Liver and lung histology was examined, and protein levels were analyzed. LPS administration reduced portal pressure, portal venous flow and cardiac index in the BDL rats. In addition, LPS administration induced acute lung injury, hypoxia and elevated TNF-α and IL-6 levels. Pre-treatment with tocilizumab did not affect hemodynamic and biochemistry data, but it ameliorated lung injury and decreased TNF-α, IL-6, and CD68-positive macrophage infiltration. Moreover, tocilizumab administration improved hypoxia and gas exchange in the BDL rats, and downregulated hepatic and pulmonary inflammatory protein expression. In conclusion, LPS administration induced acute lung injury in biliary cirrhotic rats. Pre-treatment with tocilizumab reduces lung damage and hypoxia, possibly by downregulating inflammatory proteins and reducing IL-6, TNF-α and CD68-positive macrophage recruitment in the lung.

Liver manifestation of patients with celiac disease: A single center experience.

OBJECTIVES: Characterize the clinicopathologic features of liver biopsies from patients with celiac disease (CD). METHODS: Single center, retrospective search for liver biopsies from patients with CD. RESULTS: 36 unique patients were included, median age of 46 years (range: 2-75), including 5 pediatric patients, with an overall female predominance (25, 69 %) but in in children a male predominance was seen (p = 0.023). Most cases (75 %) had an underlying condition including autoimmune hepatitis (AIH) (11 %), AIH/primary biliary cholangitis (PBC) overlap (3 %) and PBC (3 %). The median body mass index was 28, with 4 (11 %) underweight and 22 (61 %) overweight/obese patients. The most common histologic pattern was steatosis (18, 50 %), considered severe in 5 (14 %) and in 7 (19 %) regarded as steatohepatitis. The other histologic patterns included a nonspecific portal and/or lobular inflammation ("celiac hepatitis") in 9 cases (25 %), autoimmune hepatitis (3, 8 %), chronic cholestatic pattern (3, 8 %), chronic hepatitis (1, 3 %), acute lobular hepatitis (1, 3 %) and stablished cirrhosis (1, 3 %). Additionally, 2 of the cases with steatosis show cirrhosis. CONCLUSIONS: The biopsy findings from patients with CD are heterogenous and in most represent a concomitant underlying disease, particularly metabolic dysfunction-associated steatotic liver disease. Additionally, CD injury should remain in the differential diagnosis in liver biopsies with a nonspecific portal and/or lobular inflammation.

Conventional type 1 dendritic cells are essential for the development of primary biliary cholangitis.

BACKGROUND & AIMS: Primary biliary cholangitis (PBC) is a progressive-cholestatic autoimmune liver disease. Dendritic cells (DC) are professional antigen-presenting cells and their prominent presence around damaged bile ducts of PBC patients are documented. cDC1 is a rare subset of DC known for its cross-presentation abilities and interleukin 12 production. Our aim was to assess the role of cDC1 in the pathogenesis of PBC. METHODS: We utilized an inducible murine model of PBC and took advantage of the DC reporter mice Zbtb46gfp and the Batf3-/- mice that specifically lack the cDC1 subset. cDC1 cells were sorted from blood of PBC patients and healthy individuals and subjected to Bulk-MARS-seq transcriptome analysis. RESULTS: Histopathology assessment demonstrated peri-portal inflammation in wild type (WT) mice, whereas only minor abnormalities were observed in Batf3-/- mice. Flow cytometry analysis revealed a two-fold reduction in hepatic CD8/CD4 T cells ratio in Batf3-/- mice, suggesting reduced intrahepatic CD8 T cells expansion. Histological evidence of portal fibrosis was detected only in the WT but not in Batf3-/- mice. This finding was supported by decreased expression levels of pro-fibrotic genes in the livers of Batf3-/- mice. Transcriptome analysis of human cDC1, revealed 78 differentially expressed genes between PBC patients and controls. Genes related to antigen presentation, TNF and IFN signalling and mitochondrial dysfunction were significantly increased in cDC1 isolated from PBC patients. CONCLUSION: Our data illustrated the contribution the cDC1 subset in the pathogenesis of PBC and provides a novel direction for immune based cell-specific targeted therapeutic approach in PBC.

Obliteration of portal venules contributes to portal hypertension in biliary cirrhosis.

The effects of the obliteration of portal venules (OPV) in cirrhotic portal hypertension are poorly understood. To investigate its contribution to portal hypertension in biliary cirrhosis and its underlying mechanism, we evaluated OPV using two-dimensional (2D) histopathology in liver explants from patients with biliary atresia (BA, n = 63), primary biliary cholangitis (PBC, n = 18), and hepatitis B-related cirrhosis (Hep-B-cirrhosis, n = 35). Then, three-dimensional (3D) OPV was measured by X-ray phase-contrast CT in two parallel models in rats following bile duct ligation (BDL) or carbon tetrachloride (CCl4) administration, representing biliary cirrhosis and post-necrotic cirrhosis, respectively. The portal pressure was also measured in the two models. Finally, the effects of proliferative bile ducts on OPV were investigated. We found that OPV was significantly more frequent in patients with biliary cirrhosis, including BA (78.57 ± 16.45%) and PBC (60.00 ± 17.15%), than that in Hep-B-cirrhotic patients (29.43 ± 14.94%, p < 0.001). OPV occurred earlier, evidenced by the paired liver biopsy at a Kasai procedure (KP), and was irreversible even after a successful KP in the patients with BA. OPV was also significantly more frequent in the BDL models than in the CCl4 models, as shown by 2D and 3D quantitative analysis. Portal pressure was significantly higher in the BDL model than that in the CCl4 model. With the proliferation of bile ducts, portal venules were compressed and irreversibly occluded, contributing to the earlier and higher portal pressure in biliary cirrhosis. OPV, as a pre-sinusoidal component, plays a key role in the pathogenesis of portal hypertension in biliary cirrhosis. The proliferated bile ducts and ductules gradually take up the 'territory' originally attributed to portal venules and compress the portal venules, which may lead to OPV in biliary cirrhosis. © 2024 The Pathological Society of Great Britain and Ireland.

Comparative histologic features among liver biopsies with biliary-pattern injury and confirmed clinical diagnoses.

Biliary-pattern injury in the liver (eg, duct injury, ductular reaction, cholestasis) can occur in several conditions, including primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), large duct obstruction (LDO), and drug-induced liver injury (DILI). While the histologic changes in these conditions have been individually well described, distinguishing among them remains often challenging, particularly when biopsy samples are limited in size, robust clinical information is unavailable, and/or the pathologist does not feel confident in evaluating liver disease. This study evaluated histologic features that could aid the diagnosis of biliary-pattern injury on biopsy. We reviewed 121 liver biopsies from clinically confirmed cases of PBC, PSC, chronic LDO, or DILI for multiple clinical and histologic parameters. The rates of these histologic findings were then compared among different entities. Onion-skin fibrosis was seen in 14% of PSC in comparison to 0%, 5%, and 0% of PBC, DILI, and chronic LDO (P = 0.031). Florid duct lesions were identified in 21% of PBC compared to 2% of PSC and 0% of DILI and LDO (P = 0.0065). Similarly, 42% of PBC showed lobular granulomas, compared to 7% of PSC, 11% of DILI, and 33% of chronic LDO (P = 0.0001). Cholestasis was more commonly seen in DILI (42%) and chronic LDO (83%) than in PBC (4%) and PSC (16%) (P < 0.0001). Lobular chronic inflammation was found in a significantly higher percentage of PBC and LDO than of PSC and DILI (P = 0.0009). There were significantly fewer cases of PBC showing neutrophils in ductular reaction than PSC, DILI, and LDO (P = 0.0063). Histologic findings that can help suggest a diagnosis in liver biopsies with biliary-pattern injury include florid duct lesions, lobular granulomas, lack of neutrophils in ductular reaction, and lobular chronic inflammation in PBC; onion-skin fibrosis in PSC; cholestasis and feathery degeneration in DILI; and lobular granulomas, lobular chronic inflammation, cholestasis, and feathery degeneration in chronic LDO. These findings are likely most helpful when complicating factors interfere with biopsy interpretation.

Expression of E-cadherin by CD8+ T cells promotes their invasion into biliary epithelial cells.

The presence of CD8+ T cells in the cytoplasm of biliary epithelial cells (BEC) has been correlated with biliary damage associated with primary biliary cholangitis (PBC). Here, we characterise the mechanism of CD8+ T cell invasion into BEC. CD8+ T cells observed within BEC were large, eccentric, and expressed E-cadherin, CD103 and CD69. They were also not contained within secondary vesicles. Internalisation required cytoskeletal rearrangements which facilitated contact with BEC. Internalised CD8+ T cells were observed in both non-cirrhotic and cirrhotic diseased liver tissues but enriched in PBC patients, both during active disease and at the time of transplantation. E-cadherin expression by CD8+ T cells correlated with frequency of internalisation of these cells into BEC. E-cadherin+ CD8+ T cells formed ß-catenin-associated interactions with BEC, were larger than E-cadherin- CD8+ T cells and invaded into BEC more frequently. Overall, we unveil a distinct cell-in-cell structure process in the liver detailing the invasion of E-cadherin+ CD103+ CD69+ CD8+ T cells into BEC.

Prognostic significance of liver stiffness in patients with primary biliary cholangitis: validation of Baveno VII criteria.

BACKGROUND: The role of liver stiffness measurements (LSM) in patients with primary biliary cholangitis (PBC) remains to be further elucidated. AIMS: To clarify the prognostic role of LSM and to validate the "novel concepts" proposed by the Baveno VII Working Group. METHODS: An analysis of the prognostic significance of LSM was performed involving 672 patients. RESULTS: LSM and ΔLSM/ΔT were independent risk factors for liver decompensation, liver transplantation, or liver-related death (primary outcomes, p < 0.001, both). A rule of 5 kPa for LSM (10-15-20 kPa) could be used to denote progressively higher relative risks of primary outcomes. Patients with LSM < 10 kPa have a negligible 3-year risk of primary outcomes (< 1%). Cut-off values of 10 and 15 kPa can be used to classify PBC patients into low-, medium-, and high-risk groups. A clinically significant decrease in LSM, evaluated at 6, 12, or 24 months elastography tests, was associated with a substantially reduced risk of primary outcomes (p < 0.05, all), which can be defined as a decrease in LSM of > - 20% associated with LSM < 20 kPa or any decrease to LSM < 10 kPa. A clinically significant increase in LSM, evaluated at 6, 12, or 24 months elastography tests, was associated with a substantially raised risk of primary outcomes (p < 0.05, all), which can be defined as an increase in LSM of ≥ + 20% or any increase to LSM ≥ 15 kPa. CONCLUSIONS: LSM can be used to monitor disease progression and predict long-term prognosis in patients with PBC.

Increased expression of TNFRSF14 and LIGHT in biliary epithelial cells of patients with primary sclerosing cholangitis.

BACKGROUND AND AIMS: There is a lack of biliary epithelial molecular markers for primary sclerosing cholangitis (PSC). We analyzed candidates from disease susceptibility genes identified in recent genome-wide association studies (GWAS). METHODS: Expression levels of GWAS genes were analyzed in archival liver tissues of patients with PSC and controls. Immunohistochemical analysis was performed to evaluate expression levels in the biliary epithelia of PSC (N = 45) and controls (N = 12). Samples from patients with primary biliary cholangitis (PBC) were used as disease controls (N = 20). RESULTS: Hepatic expression levels of ATXN2, HHEX, PRDX5, MST1, and TNFRSF14 were significantly altered in the PSC group. We focused on the immune-related receptor, TNFRSF14. Immunohistochemistry revealed that high expression of TNFRSF14 in biliary epithelial cells was observed only in the PSC group. In addition, the expression of LIGHT, which encodes a TNFRSF14-activating ligand, was increased in PSC liver. Immunohistochemistry showed that high expression of LIGHT was more common in PSC biliary epithelia (53%) than in the PBC (15%) or control (0%) groups; moreover, it was positively associated with fibrotic progression, although it was not an independent prognostic factor. CONCLUSIONS: TNFRSF14 and LIGHT are promising candidate markers for PSC.

Estrogen receptor alpha-mediated mitochondrial damage in intrahepatic bile duct epithelial cells leading to the pathogenesis of primary biliary cholangitis.

This study investigated the effects of estrogen and estrogen receptor alpha (ERα) on the pathogenesis of primary biliary cholangitis (PBC) in human intrahepatic bile duct epithelial cells (HiBECs). The researchers measured serum levels of ERα, oxidative stress indicators, and cytokines in PBC patients and healthy controls. They examined the expression of ERα, pyruvate dehydrogenase complex E2-component (PDC-E2), and apoptosis-related proteins in the small bile ducts. In vitro experiments with HiBECs showed that estrogen had a dual effect on cell viability, increasing it at low concentrations but reducing it at higher concentrations. ERα activation led to mitochondrial damage, apoptosis, and upregulation of ERα and PDC-E2 expression. These findings suggest that the high expression of ERα in the bile ducts contributes to mitochondrial damage, inflammation, and apoptosis in PBC. The study highlights ERα as a potential target for understanding and treating estrogen-mediated PBC pathogenesis.

Histology and clinical correlations in autoimmune hepatitis, primary biliary cholangitis, and autoimmune hepatitis-primary biliary cholangitis overlap syndrome.

OBJECTIVES: The diagnosis of autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and AIH-PBC overlap syndrome (OS) relies on their histologic features and clinical findings. In this study, we aimed to identify specific morphologic features of these diseases and evaluate their clinical correlation. METHODS: We included initial biopsies from untreated patients with AIH (n = 14), PBC (n = 10), and OS (n = 7). Histologic features of the portal tract, portal-lobular interface, and hepatic lobule, fibrosis, as well as clinical data including serology, autoantibodies, treatment, and prognosis were reviewed and analyzed. RESULTS: Our results showed that several histologic features differed significantly between AIH and PBC (p < 0.05). Among these features, OS cases were more likely to present with bile duct-centered processes (presence of bile duct damage while absence of inflammation gradient from bile duct to interface, plasma cell cluster and pericentral inflammation) unlike those seen in AIH (p < 0.05), and interface-centered processes (unequivocal interface hepatitis, ductular reaction, and periportal fibrosis) which were not seen in PBC (p < 0.05). We observed a significant correlation between transaminase levels and lobular inflammation, including numbers of lymphocyte, plasma cell and eosinophil. Our study also found that anti-smooth muscle antibody positivity was associated with interface hepatitis (p < 0.01), while antimitochondrial antibody positivity was associated with duct damage (including ductopenia) and granulomas (p < 0.05). CONCLUSION: Our results highlight distinctive morphological features between AIH and PBC. The possibility of overlap syndrome should be considered when encountering AIH with bile duct-centered processes or PBC with interface-centered processes in morphology and correlation with autoantibodies.

Zebrafish ppp1r21 mutant as a model for the study of primary biliary cholangitis.

Primary biliary cholangitis (PBC) is an autoimmune cholestatic liver disease that progresses to fibrosis and cirrhosis, resulting from the gradual destruction of intrahepatic bile ducts. Exploring genetic variants associated with PBC is essential to understand the pathogenesis of PBC. Here we identify a zebrafish balloon dog (blg) mutant with intrahepatic bile duct branching defects, exhibiting several key pathological PBC-like features, including immunodominant autoantigen PDC-E2 production, cholangiocyte apoptosis, immune cell infiltration, inflammatory activation, and liver fibrosis. blg encodes the protein phosphatase 1 regulatory subunit 21 (Ppp1r21), which is enriched in the liver and its peripheral tissues and plays a vital role in the early intrahepatic bile duct formation stage. Further studies show an excessive activation of the PI3K/AKT/mTOR pathway in the hepatic tissues in the mutant, while treatment with the pathway inhibitor LY294002 and rapamycin partially rescues intrahepatic bile duct branching defects and alleviates the PBC-like symptoms. These findings implicate the potential role of the Ppp1r21-mediated PI3K/AKT/mTOR pathway in the pathophysiology of PBC.

[Roles of the CXCR1/CXCL8 axis in abnormal proliferation of bile duct epithelial cells in primary biliary cholangitis].

Objective: To investigate the role of the CXC chemokine receptor 1 (CXCR1)/CXC chemokine ligand 8 (CXCL8) axis in the abnormal proliferation of bile duct epithelial cells in primary biliary cholangitis (PBC). Methods: 30 female C57BL/6 mice were randomly divided into the PBC model group (PBC group), reparixin intervention group (Rep group), and blank control group (Con group) in an in vivo experiment. PBC animal models were established after 12 weeks of intraperitoneal injection of 2-octanoic acid coupled to bovine serum albumin (2OA-BSA) combined with polyinosinic acid polycytidylic acid (polyI:C). After successful modelling, reparixin was injected subcutaneously into the Rep group (2.5 mg · kg(-1) · d(-1), 3 weeks). Hematoxylin-eosin staining was used to detect histological changes in the liver. An immunohistochemical method was used to detect the expression of cytokeratin 19 (CK-19). Tumor necrosis factor-α (TNF-α), γ-interferon (IFN-γ) and interleukin (IL)-6 mRNA expression were detected by qRT-PCR. Western blot was used to detect nuclear transcription factor-κB p65 (NF-κB p65), extracellularly regulated protein kinase 1/2 (ERK1/2), phosphorylated extracellularly regulated protein kinase 1/2 (p-ERK1/2), Bcl-2-related X protein (Bax), B lymphoma-2 (Bcl-2), and cysteine proteinase-3 (Caspase- 3) expression. Human intrahepatic bile duct epithelial cells were divided into an IL-8 intervention group (IL-8 group), an IL-8+Reparicin intervention group (Rep group), and a blank control group (Con group) in an in vitro experiment. The IL-8 group was cultured with 10 ng/ml human recombinant IL-8 protein, and the Rep group was cultured with 10 ng/ml human recombinant IL-8 protein, followed by 100 nmol/L Reparicin. Cell proliferation was detected by the EdU method. The expression of TNF-α, IFN-γ and IL-6 was detected by an enzyme-linked immunosorbent assay. The expression of CXCR1 mRNA was detected by qRT-PCR. The expression of NF-κB p65, ERK1/2 and p-ERK1/2 was detected by western blot. A one-way ANOVA was used for comparisons between data sets. Results: The results of in vivo experiments revealed that the proliferation of cholangiocytes, the expression of NF-κB and ERK pathway-related proteins, and the expression of inflammatory cytokines were increased in the Con group compared with the PBC group. However, reparixin intervention reversed the aforementioned outcomes (P<0.05). In vitro experiments showed that the proliferation of human intrahepatic cholangiocyte epithelial cells, the expression of CXCR1 mRNA, the expression of NF-κB and ERK pathway-related proteins, and the expression of inflammatory cytokines were increased in the IL-8 group compared with the Con group. Compared with the IL-8 group, the proliferation of human intrahepatic cholangiocyte epithelial cells, NF-κB and ERK pathway-related proteins, and inflammatory indicators were significantly reduced in the Rep group (P < 0.05). Conclusion: The CXCR1/CXCL8 axis can regulate the abnormal proliferation of bile duct epithelial cells in PBC, and its mechanism of action may be related to NF-κB and ERK pathways.

Senescence and senotherapies in biliary atresia and biliary cirrhosis.

BACKGROUND: Premature senescence occurs in adult hepatobiliary diseases and worsens the prognosis through deleterious liver remodeling and hepatic dysfunction. Senescence might also arises in biliary atresia (BA), the first cause of pediatric liver transplantation. Since alternatives to transplantation are needed, our aim was to investigate premature senescence in BA and to assess senotherapies in a preclinical model of biliary cirrhosis. METHODS: BA liver tissues were prospectively obtained at hepatoportoenterostomy (n=5) and liver transplantation (n=30) and compared to controls (n=10). Senescence was investigated through spatial whole transcriptome analysis, SA-ß-gal activity, p16 and p21 expression, γ-H2AX and senescence-associated secretory phenotype (SASP). Human allogenic liver-derived progenitor cells (HALPC) or dasatinib and quercetin (D+Q) were administrated to two-month-old Wistar rats after bile duct ligation (BDL). RESULTS: Advanced premature senescence was evidenced in BA livers from early stage and continued to progress until liver transplantation. Senescence and SASP were predominant in cholangiocytes, but also present in surrounding hepatocytes. HALPC but not D+Q reduced the early marker of senescence p21 in BDL rats and improved biliary injury (serum γGT and Sox9 expression) and hepatocytes mass loss (Hnf4a). CONCLUSIONS: BA livers displayed advanced cellular senescence at diagnosis that continued to progress until liver transplantation. HALPC reduced early senescence and improved liver disease in a preclinical model of BA, providing encouraging preliminary results regarding the use of senotherapies in pediatric biliary cirrhosis.