Cutting edge issues in primary sclerosing cholangitis

Clinical guidelines for primary sclerosing cholangitis 2017

BACKGROUND

Primary sclerosing cholangitis (PSC) is relatively rare disease and pathogenesis and methods of treatments were still not established. Then, we had conducted the making clinical guidelines to manage patients with PSC based on the literature review and expert opinions. These clinical guidelines were made for the medical doctors on the management of PSC, except child case of PSC.

METHODS

We had employed modified Delphi method. The production committee decided guidelines, strength of recommendations and evidence level after reviewed literatures systematically, and The Expert panel evaluated those. The Scientific Committee of the Japan Biliary Association (JBA) evaluated revised guidelines, and the Public comments were collected on web site of JBA.

RESULTS

We had made 16 guidelines about epidemiology/pathophysiology, diagnostics, therapy and prognosis. Also, we had made both diagnostic and therapeutic flow chart.

CONCLUSIONS

We hope that these guidelines will contribute to the improvement and development of the medical care of PSC.

Update on pharmacotherapies for cholestatic liver disease

Cholestatic liver diseases are conditions with impaired bile formation and/or flow due to genetic, immunologic, environmental, or other causes. Unless successfully treated, this can lead to chronic liver injury and end‐stage liver disease. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) embody the most prominent adult cholestatic liver diseases with regard to incidence, morbidity, and mortality. A considerable proportion of patients with PBC and PSC experience progressive liver disease and ultimately liver‐related death due to a paucity of effective pharmacotherapy; however, novel pharmacologic developments offer substantial promise in this regard. Here, we provide a brief review and update on current and emerging pharmacotherapies for PBC and PSC. (Hepatology Communications 2017;1:7–17)

The Role of Genetic and Immune Factors for the Pathogenesis of Primary Sclerosing Cholangitis in Childhood

Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease characterized by chronic inflammation of the biliary tree resulting in liver fibrosis. PSC is more common in male less than 40 years of age. The diagnosis of PSC is based on clinical, laboratory, image, and histological findings. A biochemical profile of mild to severe chronic cholestasis can be observed. Endoscopic retrograde cholangiography is the golden standard method for diagnosis, but magnetic resonance cholangiography is currently also considered a first-line method of investigation. Differences in clinical and laboratory findings were observed in young patients, including higher incidence of overlap syndromes, mostly with autoimmune hepatitis, higher serum levels of aminotransferases and gamma-glutamyl transferase, and lower incidence of serious complications as cholangiocarcinoma. In spite of the detection of several HLA variants as associated factors in large multicenter cohorts of adult patients, the exact role and pathways of these susceptibility genes remain to be determined in pediatric population. In addition, the literature supports a role for an altered immune response to pathogens in the pathogenesis of PSC. This phenomenon contributes to abnormal immune system activation and perpetuation of the inflammatory process. In this article, we review the role of immune and genetic factors in the pathogenesis of PSC in pediatric patients.

Primary Sclerosing Cholangitis: Multiple Phenotypes, Multiple Approaches

Primary sclerosing cholangitis (PSC) is a heterogeneous, idiopathic, inflammatory disorder frequently associated with inflammatory bowel diseases. PSC patients may be classified into several subphenotypes. Investigations of pediatric, nonwhite, and female PSC patients have revealed distinguishing features. The natural history of PSC is variable in progression with numerous possible clinical outcomes. PSC patients may suffer bacterial cholangitis, cholangiocarcinoma, or colorectal adenocarcinoma. Treatments focusing on bile acid therapy and immunosuppression have not proven beneficial. Interest in PSC and international collaboration has led to improved understanding of the heterogeneity and the genetic structure and introduced possible effective therapeutics.

TGR5: pathogenetic role and/or therapeutic target in fibrosing cholangitis?

Primary sclerosing cholangitis (PSC) is a chronic inflammatory disease affecting the intrahepatic and extrahepatic biliary tree leading to bile duct strictures, progressive cholestasis, and development of liver fibrosis and cirrhosis. The pathogenesis of PSC is still elusive; however, both an immune-mediated injury of the bile ducts as well as increased recruitment of intestinal-primed T lymphocytes to the biliary tracts seem to contribute to disease development and progression. TGR5 (Gpbar-1) is a G-protein-coupled receptor responsive to bile acids, which is expressed in cholangiocytes, intestinal epithelial cells, and macrophages of the liver and intestine as well as in CD14-positive monocytes of the peripheral blood. Activation of TGR5 in biliary epithelial cells promotes chloride and bicarbonate secretion, triggers cell proliferation, and prevents apoptotic cell death. In immune cells, stimulation of TGR5 inhibits cytokine expression and secretion, thus reducing systemic as well as hepatic and intestinal inflammation. The expression pattern of TGR5 in the liver and intestine as well as the potential protective functions of TGR5 suggest a role for this receptor in the pathogenesis of PSC. While mutations in the coding region of the TGR5 gene are too rare to contribute to overall disease susceptibility, the expression and localization of the receptor have not been studied in PSC livers. Pharmacological activation of TGR5 in mice promotes protective mechanisms in biliary epithelial cells and reduces hepatic and systemic inflammation; however, it also provokes pruritus. Further studies are needed to predict the potential benefits as well as side effects of TGR5 agonist treatment in PSC patients.

Abnormal Liver Biochemistry Is Common in Pediatric Inflammatory Bowel Disease: Prevalence and Associations

BACKGROUND

Liver enzymes (LEs) abnormalities associated with pediatric inflammatory bowel diseases (IBD) are understudied. We undertook to describe the development and associations of abnormal LEs in pediatric IBD.

METHODS

We ascertained a cohort of 300 children with IBD and collected retrospective data. A Kaplan-Meier analysis determined the time to development of different thresholds of abnormal LEs. Associations between clinical variables and the development of abnormal LEs were determined.

RESULTS

The probability of developing the first episode of abnormal LEs above the upper limit of normal (ULN) within 150 months was 58.1% (16.3% by 1 mo post-IBD diagnosis). There was a 6% prevalence of primary sclerosing cholangitis (PSC) or autoimmune sclerosing cholangitis (ASC) in this cohort. Of those diagnosed with PSC/ASC, 93% had persistent LE elevations at a threshold of >2× ULN, while those without PSC/ASC had a 4% probability of this abnormality. Elevated gamma glutamyltranspeptidase levels of 252 U/L had a 99% sensitivity and 71% specificity for PSC/ASC in IBD. After exclusion of patients with PSC/ASC, corticosteroids, antibiotics, and exclusive enteral nutrition demonstrated strongly positive associations with the first development of abnormal LEs >ULN (hazard ratio 2.1 [95% confidence interval, 1.3-3.3], hazard ratio 5.6 [95% confidence interval, 3.6-8.9], hazard ratio 4.2 [95% confidence interval, 1.6-11.3], respectively).

CONCLUSIONS

Abnormal LEs are common in pediatric IBD and occur early. PSC/ASC is associated with persistently high LEs and gamma glutamyltranspeptidase levels >252 U/L. Children with IBD are at risk of elevated LEs if they require medications other than 5-ASA to induce IBD remission.

Autophagy and senescence in fibrosing cholangiopathies

Fibrosing cholangiopathy such as primary sclerosing cholangitis (PSC) and biliary atresia (BA) is characterized by biliary epithelial injuries and concentric fibrous obliteration of the biliary tree together with inflammatory cell infiltration. In these diseases, inappropriate innate immunity is reported to contribute more to bile duct pathology as compared with various aspects of "classical" autoimmune diseases. Primary biliary cirrhosis (PBC) is characterized by chronic cholangitis with bile duct loss and classical autoimmune features. Cellular senescence of cholangiocytes and a senescence-associated secretory phenotype lead to the production of proinflammatory cytokines and chemokines that may modify the milieu of the bile duct and then trigger fibroinflammatory responses in PSC and PBC. Furthermore, deregulated autophagy might be involved in cholangiocyte senescence and possibly in the autoimmune process in PBC, and the deregulated innate immunity against enteric microbes or their products that is associated with cholangiocyte senescence might result in the fibrosing cholangitis that develops in PBC and PSC. In BA, innate immunity against double-stranded RNA viruses might be involved in cholangiocyte apoptosis and also in the development of the epithelial-mesenchymal transition of cholangiocytes that results in fibrous obliteration of bile ducts. These recent advances in the understanding of immune-mediated biliary diseases represent a paradigm shift: the cholangiocyte is no longer viewed merely as a passive victim of injury; it is now also considered to function as a potential effector in bile duct pathology.

Mechanisms of tissue injury in autoimmune liver diseases

Autoimmune diseases affecting the liver are mainly represented by autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). The characteristic morphologic patterns of injury are a chronic hepatitis pattern of damage in AIH, destruction of small intrahepatic bile ducts in PBC and periductal fibrosis and inflammation involving larger bile ducts in PSC. The factors responsible for initiation and perpetuation of the injury in all the three autoimmune liver diseases are not understood completely but are likely to be environmental triggers on the background of genetic variation in immune regulation. In this review, we summarise the current understanding of the mechanisms underlying the breakdown of self-tolerance in autoimmune liver diseases.

Roux-en-Y choledochojejunostomy versus duct-to-duct biliary anastomosis in liver transplantation for primary sclerosing cholangitis: a meta-analysis

BACKGROUND

Roux-en-Y choledochojejunostomy and duct-to-duct anastomosis are potential methods for biliary reconstruction in liver transplantation (LT) for recipients with primary sclerosing cholangitis (PSC). However, there is controversy over which method yields superior outcomes. The purpose of this study was to evaluate the outcomes of duct-to-duct versus Roux-en-Y biliary anastomosis in patients undergoing LT for PSC.

METHODS

Studies comparing Roux-en-Y versus duct-to-duct anastomosis during LT for PSC were identified based on systematic searches of 9 electronic databases and multiple sources of gray literature.

RESULTS

The search identified 496 citations, including 7 retrospective series, and 692 patients met eligibility criteria. The use of duct-to-duct anastomosis was not associated with a significant difference in clinical outcomes, including 1-year recipient survival rates (odds ratio [OR], 1.02; 95% confidence interval [CI], 0.65-1.60; P = .95), 1-year graft survival rates (OR, 1.11; 95% CI, 0.72-1.71; P = .64), risk of biliary leaks (OR, 1.23; 95% CI, 0.59-2.59; P = .33), risk of biliary strictures (OR, 1.99; 95% CI, 0.98-4.06; P = .06), or rate of recurrence of PSC (OR, 0.94; 95% CI, 0.19-4.78; P = .94).

CONCLUSIONS

There were no significant differences in 1-year recipient survival, 1-year graft survival, risk of biliary complications, and PSC recurrence between Roux-en-Y and duct-to-duct biliary anastomosis in LT for PSC.

Immunomodulatory effect of vancomycin on Treg in pediatric inflammatory bowel disease and primary sclerosing cholangitis

Vancomycin has been shown to affect tumor necrosis factor-alpha (TNF-α) pathways as an immunomodulator; this is thought to be separate from its function as an antibiotic [1]. Previous studies have shown that oral vancomycin (OV) is an effective treatment for concomitant primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD) in children [2, 3]. Since both diseases are associated with immune dysfunction, we hypothesized that vancomycin's therapeutic effect in IBD and PSC occurs through immunomodulation. Therefore, we examined the in vivo immunological changes that occur during OV treatment of 14 children with PSC and IBD. Within 3 months of OV administration, peripheral gamma-glutamyl transpeptidase (GGT) and alanine aminotransferase (ALT) concentrations, white blood cell (WBC) counts, and neutrophil counts normalized from elevated levels before treatment. Patients also demonstrated improved biliary imaging studies, liver biopsies and IBD symptoms and biopsies. Additionally, plasma transforming growth factor beta (TGF-β) levels were increased without concurrent shifts in Th1-or Th2-associated cytokine production. Peripheral levels of CD4 + CD25hiCD127lo and CD4 + FoxP3+ regulatory T (Treg) cells also increased in OV-treated PSC + IBD patients compared to pretreatment levels. A unique case study shows that the therapeutic effects of OV in the treatment of PSC + IBD do not always endure after OV discontinuation, with relapse of PSC associated with a decrease in blood Treg levels; subsequent OV retreatment was then associated with a rise in blood Treg levels and normalization of liver function tests (LFTs). Taken together, these studies support immune-related pathophysiology of PSC with IBD, which is responsive to OV.

Management of primary sclerosing cholangitis: conventions and controversies

Primary sclerosing cholangitis (PSC) is a chronic inflammatory cholangiopathy that results in fibrotic strictures and dilations of the intra- and extrahepatic bile ducts. PSC is uncommon, occurs predominantly in males and has a strong association with inflammatory bowel disease. While the pathogenesis of PSC has not been fully elucidated, emerging evidence supports roles for the innate and adaptive immune systems, and genome-wide analyses have identified several genetic associations. Using the best available evidence, the present review summarizes the current understanding of the diagnosis, pathogenesis and management of PSC. Despite its rarity, there is an urgent need for collaborative research efforts to advance therapeutic options for PSC beyond liver transplantation.

Mechanisms and pathophysiology of autoimmune disease

The first textbook on autoimmunity was published by Ian Mackay and McFarland Burnett in 1963. It was the first attempt to summarize existing knowledge on human autoimmunity. Since that time, there have been tens of thousands of experimental papers and numerous textbooks that focus on the diagnosis and treatment of human autoimmunity. There have been at least as many, if not more, directed at similar issues in animal models. Enormous strides have been made not only in diagnosis, but also in the pathophysiology and especially in treatment. We have gone from the era of simple HLA typing to deep sequencing and, more recently, epigenetic analysis. We have gone from the era of white blood cell differentials to detailed lymphoid phenotyping. We have gone from the era of simple antinuclear antibodies to detailed and sophisticated immunodiagnosis with recombinant autoantigens and disease-specific epitopes. We have gone from the era of using only corticosteroids to selective biologic agents. Diseases that were previously considered idiopathic are now very much understood as autoimmune. We are in the era of autoinflammatory reactions and the concept of both innate versus adaptive immunity in mediating immunopathology. In this edition of Clinical Reviews in Allergy and Immunology, we focus on key and cutting-edge issues in the pathophysiology of autoimmunity. The issues are very much oriented and driven by hypothesis, i.e., a prediction of events expected to occur based on observations. It is not meant to be a complete summary of potential mechanisms of autoimmunity, but rather an attempt to accelerate discussion and better understanding. The primary goal is obviously to help our patients with autoimmune disease.

Macrophage-stimulating protein polymorphism rs3197999 is associated with a gain of function: implications for inflammatory bowel disease

Crohn's disease and ulcerative colitis, the two main types of inflammatory bowel disease (IBD), were reported to be associated with a variety of genetic polymorphisms. A subset of these polymorphisms was identified in both diseases and only three of them were found in primary sclerosing cholangitis (PSC). rs3197999 (Arg689Cys) located in the MST1 gene is one of the most convincingly replicated IBD/PSC-associated polymorphisms but its functional consequences have not been investigated, yet. We expressed both MST1 gene variants (Arg(689) (MSP(wt)) and Cys(689) (MSP(mut)) in a eukaryotic cell system and compared their stimulatory effects on macrophage-like THP-1 cells. Except for the rate of apoptosis that remained unchanged, MSP(mut) significantly increased the stimulatory effect of MSP (macrophage-stimulating protein) on chemotaxis and proliferation by THP-1 cells, indicating a gain of function associated with the Arg689Cys exchange. A broad set of evidence reported previously suggests that pro-inflammatory changes in macrophage function have a major role in the initiation of the inflammatory process in IBD and PSC. Therefore, the gain of function observed with rs3197999 in MST1 might provide a cellular mechanism for the consistent association of this polymorphism with an increased risk for IBD and PSC.