Adequate versus deep response to ursodeoxycholic acid in primary biliary cholangitis: To what extent and under what conditions is normal alkaline phosphatase level associated with complication-free survival gain?

BACKGROUND AND AIMS: Normal alkaline phosphatase (ALP) levels in ursodeoxycholic acid (UDCA)-treated patients with primary biliary cholangitis (PBC) are associated with better long-term outcome. However, second-line therapies are currently recommended only when ALP levels remain above 1.5 times the upper limit of normal (×ULN) after 12-month UDCA. We assessed whether, in patients considered good responders to UDCA, normal ALP levels were associated with significant survival gains. APPROACH AND RESULTS: We performed a retrospective cohort study of 1047 patients with PBC who attained an adequate response to UDCA according to Paris-2 criteria. Time to liver-related complications, liver transplantation, or death was assessed using adjusted restricted mean survival time (RMST) analysis. The overall incidence rate of events was 17.0 (95% CI: 13.7-21.1) per 1000 out of 4763.2 patient-years. On the whole population, normal serum ALP values (but not normal gamma-glutamyl transpeptidase (GGT), alanine aminotransferase (ALT), or aspartate aminotransferase (AST); or total bilirubin < 0.6 ×ULN) were associated with a significant absolute complication-free survival gain at 10 years (mean 7.6 months, 95% CI: 2.7 - 12.6 mo.; p = 0.003). In subgroup analysis, this association was significant in patients with a liver stiffness measurement ≥ 10 kPa and/or age ≤ 62 years, with a 10-year absolute complication-free survival gain of 52.8 months (95% CI: 45.7-59.9, p < 0.001) when these 2 conditions were met. CONCLUSIONS: PBC patients with an adequate response to UDCA and persistent ALP elevation between 1.1 and 1.5 ×ULN, particularly those with advanced fibrosis and/or who are sufficiently young, remain at risk of poor outcome. Further therapeutic efforts should be considered for these patients.

Spontaneous perforation of the common bile duct: an uncommon complication of primary sclerosing cholangitis.

OBJECTIVES: To describe the MR features and prognosis of patients with an uncommon complication of primary sclerosing cholangitis (PSC) characterized by a spontaneous perforation of the common bile duct (CBD) resulting in a peri-biliary collection and a pseudo-cystic appearance of the CBD. METHODS: A single-center cohort of 263 patients with PSC who had at least two MRIs between 2003 and 2022 and a minimum follow-up of 1 year was retrospectively analyzed. MRI data (characteristics of CBD perforation and MR features of PSC) and clinical data were assessed. Analysis of survival without liver transplantation according to type of PSC (classical or CBD spontaneous perforation) was performed according to the Kaplan-Meier method and the curves were compared using the Log-Rank test. RESULTS: A total of nine (3.4%) PSC patients (5 males) had perforation of the CBD with a median age at diagnosis of 18 years compared to 33 years for the control group (p = 0.019). The peri-biliary collections were variable in appearance (fusiform or pedunculated), with a diameter ranging from 5 to 54 mm. All nine patients showed intra- and extra-hepatic bile duct involvement, dysmorphia, and high ANALI scores. The clinical course was characterized by numerous complications in most patients, and five patients (56%) underwent liver transplantation at a median time of 5 years from diagnosis, compared to 40 patients (16%) in the control group (p = 0.02). CONCLUSION: The spontaneous perforation of the common bile duct is an uncommon complication of primary sclerosing cholangitis that affects young patients and is associated with a poor prognosis. CLINICAL RELEVANCE STATEMENT: This uncommon complication of primary sclerosing cholangitis with perforation of the common bile duct resulting in a peri-biliary collection and a pseudo-cystic appearance of the common bile duct is characterized by a poor prognosis in younger patients. KEY POINTS: • Among 263 patients with primary sclerosing cholangitis (PSC), nine patients (3.6%) had an uncommon complication characterized on MRI by perforation of the common bile duct (CBD). • This perforation of the CBD was responsible in all nine cases for the formation of a peri-biliary collection, giving a pseudo-cystic appearance to the CBD. • The spontaneous perforation of the common bile duct is an uncommon complication of primary sclerosing cholangitis that affects young patients with a poor prognosis.

Portal fibroblasts with mesenchymal stem cell features form a reservoir of proliferative myofibroblasts in liver fibrosis.

BACKGROUND AND AIMS: In liver fibrosis, myofibroblasts derive from HSCs and as yet undefined mesenchymal cells. We aimed to identify portal mesenchymal progenitors of myofibroblasts. APPROACH AND RESULTS: Portal mesenchymal cells were isolated from mouse bilio-vascular tree and analyzed by single-cell RNA-sequencing. Thereby, we uncovered the landscape of portal mesenchymal cells in homeostatic mouse liver. Trajectory analysis enabled inferring a small cell population further defined by surface markers used to isolate it. This population consisted of portal fibroblasts with mesenchymal stem cell features (PMSCs), i.e., high clonogenicity and trilineage differentiation potential, that generated proliferative myofibroblasts, contrasting with nonproliferative HSC-derived myofibroblasts (-MF). Using bulk RNA-sequencing, we built oligogene signatures of the two cell populations that remained discriminant across myofibroblastic differentiation. SLIT2, a prototypical gene of PMSC/PMSC-MF signature, mediated profibrotic and angiogenic effects of these cells, which conditioned medium promoted HSC survival and endothelial cell tubulogenesis. Using PMSC/PMSC-MF 7-gene signature and slit guidance ligand 2 fluorescent in situ hybridization, we showed that PMSCs display a perivascular portal distribution in homeostatic liver and largely expand with fibrosis progression, contributing to the myofibroblast populations that form fibrotic septa, preferentially along neovessels, in murine and human liver disorders, irrespective of etiology. We also unraveled a 6-gene expression signature of HSCs/HSC-MFs that did not vary in these disorders, consistent with their low proliferation rate. CONCLUSIONS: PMSCs form a small reservoir of expansive myofibroblasts, which, in interaction with neovessels and HSC-MFs that mainly arise through differentiation from a preexisting pool, underlie the formation of fibrotic septa in all types of liver diseases.

A Placebo-Controlled Trial of Bezafibrate in Primary Biliary Cholangitis.

BACKGROUND: Patients with primary biliary cholangitis who have an inadequate response to therapy with ursodeoxycholic acid are at high risk for disease progression. Fibrates, which are agonists of peroxisome proliferator-activated receptors, in combination with ursodeoxycholic acid, have shown potential benefit in patients with this condition. METHODS: In this 24-month, double-blind, placebo-controlled, phase 3 trial, we randomly assigned 100 patients who had had an inadequate response to ursodeoxycholic acid according to the Paris 2 criteria to receive bezafibrate at a daily dose of 400 mg (50 patients), or placebo (50 patients), in addition to continued treatment with ursodeoxycholic acid. The primary outcome was a complete biochemical response, which was defined as normal levels of total bilirubin, alkaline phosphatase, aminotransferases, and albumin, as well as a normal prothrombin index (a derived measure of prothrombin time), at 24 months. RESULTS: The primary outcome occurred in 31% of the patients assigned to bezafibrate and in 0% assigned to placebo (difference, 31 percentage points; 95% confidence interval, 10 to 50; P<0.001). Normal levels of alkaline phosphatase were observed in 67% of the patients in the bezafibrate group and in 2% in the placebo group. Results regarding changes in pruritus, fatigue, and noninvasive measures of liver fibrosis, including liver stiffness and Enhanced Liver Fibrosis score, were consistent with the results of the primary outcome. Two patients in each group had complications from end-stage liver disease. The creatinine level increased 5% from baseline in the bezafibrate group and decreased 3% in the placebo group. Myalgia occurred in 20% of the patients in the bezafibrate group and in 10% in the placebo group. CONCLUSIONS: Among patients with primary biliary cholangitis who had had an inadequate response to ursodeoxycholic acid alone, treatment with bezafibrate in addition to ursodeoxycholic acid resulted in a rate of complete biochemical response that was significantly higher than the rate with placebo and ursodeoxycholic acid therapy. (Funded by Programme Hospitalier de Recherche Clinique and Arrow Génériques; BEZURSO ClinicalTrials.gov number, NCT01654731 .).

Fungi participate in the dysbiosis of gut microbiota in patients with primary sclerosing cholangitis.

OBJECTIVE: Patients with primary sclerosing cholangitis (PSC) were previously shown to display a bacterial gut dysbiosis but fungal microbiota has never been examined in these patients. The aim of this study was to assess the fungal gut microbiota in patients with PSC. DESIGN: We analysed the faecal microbiota of patients with PSC and concomitant IBD (n=27), patients with PSC and no IBD (n=22), patients with IBD and no PSC (n=33) and healthy subjects (n=30). Bacterial and fungal composition of the faecal microbiota was determined using 16S and ITS2 sequencing, respectively. RESULTS: We found that patients with PSC harboured bacterial dysbiosis characterised by a decreased biodiversity, an altered composition and a decreased correlation network density. These alterations of the microbiota were associated with PSC, independently of IBD status. For the first time, we showed that patients with PSC displayed a fungal gut dysbiosis, characterised by a relative increase in biodiversity and an altered composition. Notably, we observed an increased proportion of Exophiala and a decreased proportion of Saccharomyces cerevisiae. Compared with patients with IBD and healthy subjects, the gut microbiota of patients with PSC exhibited a strong disruption in bacteria-fungi correlation network, suggesting an alteration in the interkingdom crosstalk. CONCLUSION: This study demonstrates that bacteria and fungi contribute to gut dysbiosis in PSC.

Simple Magnetic Resonance Scores Associate With Outcomes of Patients With Primary Sclerosing Cholangitis.

BACKGROUND & AIMS: Primary sclerosing cholangitis (PSC) has a variable, often progressive, course. Magnetic resonance cholangiography (MRC) is used in the diagnosis of PSC. Magnetic resonance risk scoring systems, called Anali without and with gadolinium, are used to predict disease progression, determined by radiologic factors. We aimed to assess the prognostic value of Anali scores in patients with PSC and validate our findings in a separate cohort. METHODS: We performed a retrospective study of patients with large-duct PSC (internal cohort, 119 patients in France; external cohort, 119 patients in Canada, Italy, and the United Kingdom). All the first-available MRC results were reviewed by 2 radiologists and the Anali scores were calculated as follows: Anali without gadolinium = (1× dilatation of intrahepatic bile ducts) + (2× dysmorphy) + (1× portal hypertension); Anali with gadolinium = (1× dysmorphy) + (1× parenchymal enhancement heterogeneity). The primary end point was survival without liver transplantation or cirrhosis decompensation. The prognostic value of Anali scores was assessed by Cox regression modeling. RESULTS: During a total of 549 patient-years for the internal cohort and 497 patient-years for the external cohort, we recorded 2 and 8 liver transplantations, 4 and 3 liver-related deaths, and 26 and 25 cirrhosis decompensations, respectively. In the univariate analysis, factors associated with survival without liver transplantation or cirrhosis decompensation in the internal cohort were as follows: serum levels of bilirubin, aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transferase, alkaline phosphatase, albumin, and Anali scores. Anali scores without and with gadolinium identified patients' survival without liver transplantation or cirrhosis decompensation with a c-statistic of 0.89 (95% CI, 0.84-0.95) and 0.75 (95% CI, 0.64-0.87), respectively. Independent prognostic factors identified by multivariate analysis were Anali scores and bilirubinemia. The prognostic value of Anali scores was confirmed in the external cohort. CONCLUSIONS: In internal and external cohorts, we found that Anali scores, determined from MRC, were associated with outcomes of patients with PSC. These scores might be used as prognostic factors.

The Complementary Value of Magnetic Resonance Imaging and Vibration-Controlled Transient Elastography for Risk Stratification in Primary Sclerosing Cholangitis.

OBJECTIVES: Magnetic resonance (MR) risk scores and liver stiffness (LS) have individually been shown to predict clinical outcomes in primary sclerosing cholangitis (PSC). The aim of this study was to assess their complementary prognostic value. METHODS: Patients with PSC from 3 European centers with a 3-dimensional MR cholangiography available for central reviewing and a valid LS measurement assessed by vibration-controlled transient elastography by FibroScan performed within a 6-month interval were included in a longitudinal retrospective study. The MR score (Anali) without gadolinium (Gd) was calculated according to the formula: (1 × dilatation of intrahepatic bile ducts) + (2 × dysmorphy) + (1 × portal hypertension). The primary end point was survival without liver transplantation or cirrhosis decompensation. The prognostic values of LS and Anali score without Gd were assessed using Cox proportional hazard models. RESULTS: One hundred sixty-two patients were included. Over a total follow-up of 753 patient-years, 40 patients experienced an adverse outcome (4 liver transplantations, 6 liver-related deaths, and 30 cirrhosis decompensations). LS and Anali score without Gd were significantly correlated (ρ = 0.51, P < 0.001) and were independently associated with the occurrence of an adverse outcome. Optimal prognostic thresholds were 10.5 kPa for LS and 2 for the Anali score without Gd. Hazard ratios (95% confidence interval) were 2.07 (1.06-4.06) and 3.78 (1.67-8.59), respectively. The use in combination of these 2 thresholds allowed us to separate patients into low-, medium-, and high-risk groups for developing adverse outcomes. The 5-year cumulative rates of adverse outcome in these 3 groups were 8%, 16%, and 38% (P < 0.001), respectively. DISCUSSION: The combined use of MRI and vibration-controlled transient elastography permits easy risk stratification of patients with PSC.

Intrahepatic cystic biliary dilatation constitutes a significant prognostic factor in patients with primary sclerosing cholangitis.

AIMS: To evaluate the prognostic value of cystic dilatation (CD) of the intrahepatic biliary ducts in patients with primary sclerosing cholangitis (PSC). METHODS: A single-center cohort of 205 patients with PSC from 2003 to 2016 was analysed. CD was defined by quantitative and qualitative criteria. Radiological and clinical courses were assessed. A Kaplan-Meier analysis was used to estimate cumulative survival without liver transplantation (LT) from the date of PSC diagnosis. A log-rank test was performed to compare survival time of PSC patients with and without CD. RESULTS: A total of 15 (7.3%) PSC patients (12 males) with a median age of 23 years at diagnosis had CD. Five patients had one CD; seven patients had two or three CDs; and three patients had diffuse CD. CDs ranged in small diameter size from 12 to 32 mm. Radiological evolution of CD was markedly variable. However, a radiological worsening of PSC over time was observed in all patients. The clinical course was characterized by the occurrence of complications in most patients. Half of the patients with CD underwent LT at a median time of 40 months from diagnosis of CD and the median survival time from PSC diagnosis was significantly lower than in PSC without CD (10.7 vs. 23.4 years; HR 3.8, 95% confidence interval: 1.7-8.3, p = 0.001). CONCLUSIONS: CD in PSC is an unusual condition that mostly affects young patients. It is characterized by a rapid, unfavorable course and constitutes a significant prognostic factor. KEY POINTS: • Cystic dilatation of the intrahepatic biliary ducts affects young patients with primary sclerosing cholangitis and is characterized by a markedly variable radiological evolution. • Biliary wall inflammation, found in explanted livers, could be a key feature in the pathogenesis of cystic dilatation. • Cystic dilatation of the intrahepatic biliary ducts is characterized by an unfavorable course and constitutes a significant prognostic factor of primary sclerosing cholangitis.

Liver sinusoidal endothelial cells: Physiology and role in liver diseases.

Liver sinusoidal endothelial cells (LSECs) are highly specialized endothelial cells representing the interface between blood cells on the one side and hepatocytes and hepatic stellate cells on the other side. LSECs represent a permeable barrier. Indeed, the association of 'fenestrae', absence of diaphragm and lack of basement membrane make them the most permeable endothelial cells of the mammalian body. They also have the highest endocytosis capacity of human cells. In physiological conditions, LSECs regulate hepatic vascular tone contributing to the maintenance of a low portal pressure despite the major changes in hepatic blood flow occurring during digestion. LSECs maintain hepatic stellate cell quiescence, thus inhibiting intrahepatic vasoconstriction and fibrosis development. In pathological conditions, LSECs play a key role in the initiation and progression of chronic liver diseases. Indeed, they become capillarized and lose their protective properties, and they promote angiogenesis and vasoconstriction. LSECs are implicated in liver regeneration following acute liver injury or partial hepatectomy since they renew from LSECs and/or LSEC progenitors, they sense changes in shear stress resulting from surgery, and they interact with platelets and inflammatory cells. LSECs also play a role in hepatocellular carcinoma development and progression, in ageing, and in liver lesions related to inflammation and infection. This review also presents a detailed analysis of the technical aspects relevant for LSEC analysis including the markers these cells express, the available cell lines and the transgenic mouse models. Finally, this review provides an overview of the strategies available for a specific targeting of LSECs.

Portal myofibroblasts connect angiogenesis and fibrosis in liver.

Liver fibrogenesis is a dynamic process including quantitative and qualitative changes of the extracellular matrix, of which the most prominent is the deposition of type I collagen. These changes progressively disrupt normal liver architecture and result in cirrhosis formation. In the fibrotic liver, as in all other fibrotic tissues, the extracellular matrix is produced by cells usually characterized by the de novo expression of alpha-smooth muscle actin and known as myofibroblasts. Portal myofibroblasts (PMFs) appear to be critical in pathological angiogenesis, which constantly occurs in advanced liver fibrosis. Whereas the association between angiogenesis and fibrosis during the progression of liver diseases remains to be elucidated, we suggest that collagen-type-XV-alpha1-producing PMFs could provide an important link both by stabilizing newly formed vessels and by forming a scaffold for the deposition of interstitial collagen.

Portal myofibroblasts promote vascular remodeling underlying cirrhosis formation through the release of microparticles.

UNLABELLED: Liver fibrosis expanding from portal tracts and vascular remodeling are determinant factors in the progression of liver diseases to cirrhosis. In the present study, we examined the potential contribution of portal myofibroblasts (PMFs) to the vascular changes leading to cirrhosis. The analyses of liver cells based on the transcriptome of rat PMFs, compared to hepatic stellate cell HSC-derived myofibroblasts in culture, identified collagen, type XV, alpha 1 (COL15A1) as a marker of PMFs. Normal liver contained rare COL15A1-immunoreactive cells adjacent to the bile ducts and canals of Hering in the portal area. A marked increase in COL15A1 expression occurred together with that of the endothelial marker, von Willebrand factor, in human and rat liver tissue, at advanced stages of fibrosis caused by either biliary or hepatocellular injury. In cirrhotic liver, COL15A1-expressing PMFs adopted a perivascular distribution outlining vascular capillaries proximal to reactive ductules, within large fibrotic septa. The effect of PMFs on endothelial cells (ECs) was evaluated by in vitro and in vivo angiogenesis assays. PMF-conditioned medium increased the migration and tubulogenesis of liver ECs as well as human umbilical vein ECs and triggered angiogenesis within Matrigel plugs in mice. In coculture, PMFs developed intercellular junctions with ECs and enhanced the formation of vascular structures. PMFs released vascular endothelial growth factor (VEGF)A-containing microparticles, which activated VEGF receptor 2 in ECs and largely mediated their proangiogenic effect. Cholangiocytes potentiated the angiogenic properties of PMFs by increasing VEGFA expression and microparticle shedding in these cells. CONCLUSION: PMFs are key cells in hepatic vascular remodeling. They signal to ECs through VEGFA-laden microparticles and act as mural cells for newly formed vessels, driving scar progression from portal tracts into the parenchyma.

Radiologic course of primary sclerosing cholangitis: assessment by three-dimensional magnetic resonance cholangiography and predictive features of progression.

UNLABELLED: Magnetic resonance imaging (MRI) with magnetic resonance cholangiography (MRC) has become the radiologic standard of reference for diagnosis of primary sclerosing cholangitis (PSC). However, natural history of radiologic features of PSC is poorly known. In the current study, we aimed at analyzing the course of PSC using three-dimensional (3D) MRC and liver MRI to find predictive radiologic features of progression. PSC patients, followed up in our center, with at least two 3D MRCs performed in at least a 1-year interval, were retrospectively reviewed. We built an interpretation standard model to score precisely bile ducts and liver parenchyma features. The primary endpoint was overall radiologic course, including worsening, improvement, or stabilization. Radiologic features were analyzed by logistic regression. We reviewed 289 MRIs from 64 patients upon a mean radiologic follow-up of 4 years (range, 1-9). Radiologic features worsened in 37 patients (58%) and stabilized in 27 (42%); no patient showed improvement. Multivariate analysis resulted in two MRI progression risk scores, based on the combination of predictive radiologic features (score without gadolinium administration = 1 × dilatation of intrahepatic bile ducts + 2 × dysmorphy + 1 × portal hypertension; score with gadolinium administration = 1 × dysmorphy + 1 × parenchymal enhancement heterogeneity). These scores were associated with radiologic progression, with an area under the curve of 80 and 83% ± 4%. CONCLUSION: A majority of PSC patients develop radiologic aggravation upon MRI over 4 years. Two simple scores can predict radiologic progression.

Origins and functions of liver myofibroblasts.

Myofibroblasts combine the matrix-producing functions of fibroblasts and the contractile properties of smooth muscle cells. They are the main effectors of fibrosis in all tissues and make a major contribution to other aspects of the wound healing response, including regeneration and angiogenesis. They display the de novo expression of α-smooth muscle actin. Myofibroblasts, which are absent from the normal liver, are derived from two major sources: hepatic stellate cells (HSCs) and portal mesenchymal cells in the injured liver. Reliable markers for distinguishing between the two subpopulations at the myofibroblast stage are currently lacking, but there is evidence to suggest that both myofibroblast cell types, each exposed to a particular microenvironment (e.g. hypoxia for HSC-MFs, ductular reaction for portal mesenchymal cell-derived myofibroblasts (PMFs)), expand and exert specialist functions, in scarring and inflammation for PMFs, and in vasoregulation and hepatocellular healing for HSC-MFs. Angiogenesis is a major mechanism by which myofibroblasts contribute to the progression of fibrosis in liver disease. It has been clearly demonstrated that liver fibrosis can regress, and this process involves a deactivation of myofibroblasts, although probably not to a fully quiescent phenotype. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.

Obeticholic acid as a second-line treatment for low phospholipid-associated cholelithiasis syndrome.

BACKGROUND: Low phospholipid-associated cholelithiasis (LPAC) syndrome is a rare genetic cause of hepatolithiasis. A pathogenic variant of the ABCB4 gene is reported in half of all patients. Ursodeoxycholic acid (UDCA) is the only drug approved. However, in some patients, UDCA fails to prevent recurrence of symptoms and complications. Experimental evidence suggests that agonists of the farnesoid-X receptor (FXR), the main transcription factor regulating ABCB4, may be beneficial in this context. AIM: To study the efficacy of obeticholic acid (OCA) in patients with LPAC syndrome with an inadequate response or intolerance to UDCA. METHODS: This was a retrospective study of patients with LPAC syndrome treated with OCA, a selective FXR agonist. RESULTS: We reviewed the records of five OCA-treated patients (4 women; median age 29; ABCB4 variant in 4; no hepatic fibrosis). All patients received OCA at an initial dose of 5 mg daily and then 10 mg daily for a median period of 36 months in combination with UDCA (4 patients) or as a monotherapy (one patient). There were no adverse effects reported. Four patients had improvement in their symptoms - three completely and one partially. One patient had no clinical benefit. Abnormalities of blood liver tests persisted in one patient despite resolution of symptoms. Radiological signs of hepatolithiasis persisted in three of the four patients who responded clinically to OCA. CONCLUSIONS: These preliminary observations suggest that OCA may have the potential to effectively treat LPAC syndrome in patients with inadequate response or intolerance to UDCA. Larger studies are needed to confirm these data.

Impact of cholecystectomy on the gut-liver axis and metabolic disorders.

Cholecystectomy is considered as a safe procedure to treat patients with gallstones. However, epidemiological studies highlighted an association between cholecystectomy and metabolic disorders, such as type 2 diabetes mellitus and metabolic dysfunction-associated steatotic liver disease (MASLD), independently of the gallstone disease. Following cholecystectomy, bile acids flow directly from the liver into the intestine, leading to changes in the entero-hepatic circulation of bile acids and their metabolism. The changes in bile acids metabolism impact the gut microbiota. Therefore, cholecystectomized patients display gut dysbiosis characterized by a reduced diversity, a loss of bacteria producing short-chain fatty acids and an increase in pro-inflammatory bacteria. Alterations of both bile acids metabolism and gut microbiota occurring after cholecystectomy can promote the development of metabolic disorders. In this review, we discuss the impact of cholecystectomy on bile acids and gut microbiota and its consequences on metabolic functions.

Protective potential of the gallbladder in primary sclerosing cholangitis.

Background & Aims: Gallbladder enlargement is common in patients with primary sclerosing cholangitis (PSC). The gallbladder may confer hepatoprotection against bile acid overload, through the sequestration and cholecystohepatic shunt of bile acids. The aim of this study was to assess the potential impact of the gallbladder on disease features and bile acid homeostasis in PSC. Methods: Patients with PSC from a single tertiary center who underwent liver MRI with three-dimensional cholangiography and concomitant analyses of serum bile acids were included. Gallbladder volume was measured by MRI and a cut-off of 50 ml was used to define gallbladder enlargement. Bile acid profiles and PSC severity, as assessed by blood tests and MRI features, were compared among patients according to gallbladder size (enlarged vs. normal-sized) or presence (removed vs. conserved). The impact of cholecystectomy was also assessed in the Abcb4 knockout mouse model of PSC. Results: Sixty-one patients with PSC, all treated with ursodeoxycholic acid (UDCA), were included. The gallbladder was enlarged in 30 patients, whereas 11 patients had been previously cholecystectomized. Patients with enlarged gallbladders had significantly lower alkaline phosphatase, a lower tauro-vs. glycoconjugate ratio and a higher UDCA vs. total bile acid ratio compared to those with normal-sized gallbladders. In addition, gallbladder volume negatively correlated with the hydrophobicity index of bile acids. Cholecystectomized patients displayed significantly higher aspartate aminotransferase and more severe bile duct strictures and dilatations compared to those with conserved gallbladder. In the Abcb4 knockout mice, cholecystectomy caused an increase in hepatic bile acid content and in circulating secondary bile acids, and an aggravation in cholangitis, inflammation and liver fibrosis. Conclusion: Altogether, our findings indicate that the gallbladder fulfills protective functions in PSC. Impact and implications: In patients with primary sclerosing cholangitis (PSC), gallbladder status impacts on bile acid homeostasis and disease features. We found evidence of lessened bile acid toxicity in patients with PSC and enlarged gallbladders and of increased disease severity in those who were previously cholecystectomized. In the Abcb4 knockout mouse model of PSC, cholecystectomy causes an aggravation of cholangitis and liver fibrosis. Overall, our results suggest that the gallbladder plays a protective role in PSC.

Hepatic stellate cells maintain liver homeostasis through paracrine neurotrophin-3 signaling that induces hepatocyte proliferation.

Organ size is maintained by the controlled proliferation of distinct cell populations. In the mouse liver, hepatocytes in the midlobular zone that are positive for cyclin D1 (CCND1) repopulate the parenchyma at a constant rate to preserve liver mass. Here, we investigated how hepatocyte proliferation is supported by hepatic stellate cells (HSCs), pericytes that are in close proximity to hepatocytes. We used T cells to ablate nearly all HSCs in the murine liver, enabling the unbiased characterization of HSC functions. In the normal liver, complete loss of HSCs persisted for up to 10 weeks and caused a gradual reduction in liver mass and in the number of CCND1+ hepatocytes. We identified neurotrophin-3 (Ntf-3) as an HSC-produced factor that induced the proliferation of midlobular hepatocytes through the activation of tropomyosin receptor kinase B (TrkB). Treating HSC-depleted mice with Ntf-3 restored CCND1+ hepatocytes in the midlobular region and increased liver mass. These findings establish that HSCs form the mitogenic niche for midlobular hepatocytes and identify Ntf-3 as a hepatocyte growth factor.

Non-invasive diagnosis and follow-up of autoimmune hepatitis.

Autoimmune hepatitis (AIH) is a liver disease characterised by necrotico-inflammatory lesions of hepatocytes, the presence of specific autoantibodies and response to corticosteroid treatment. AIH must be considered in any patient with acute or chronic liver disease. As there is no pathognomonic sign of AIH, the diagnosis is based on a combination of clinical, biological, immunological and histological findings, after excluding other causes of liver disease. The clinical and biological presentation of AIH is variable and AIH can be associated with an autoimmune biliary disease, primary biliary cholangitis or primary sclerosing cholangitis in an overlap syndrome. For these reasons, diagnosis of AIH can be challenging. Even if liver histology remains essential in the diagnosis of AIH, non-invasive tests can be used at different steps of the management of AIH: diagnosis of AIH, notably diagnosis of an overlap syndrome, assessment of severity of AIH, searching for extra-hepatic disease frequently associated to AIH, evaluation of response to therapy, decision of treatment withdrawal. This review aims to provide practical guidelines for the use of non-invasive tests for the diagnosis and the follow-up of AIH.