Minocycline in the treatment of patients with primary sclerosing cholangitis: results of a pilot study

Novel preclinical developments of the primary sclerosing cholangitis treatment landscape

INTRODUCTION

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease associated with inflammation, fibrosis, and destruction of intra- and extrahepatic bile ducts. Despite substantial recent advances in our understanding of PSC, the only proven treatment of PSC is liver transplantation. There is an urgent unmet need to find medical therapies for this disorder.

AREAS COVERED

Multiple drugs are currently under evaluation as therapeutic options for this disease. This article summarizes the literature on the various novel therapeutic options that have been investigated and are currently under development for the treatment of PSC.

EXPERT OPINION

In the next decade, more than one drug will likely be approved for the treatment of the disease, and we will be looking at combination therapies for the optimal management of the disease.

Treatment of Primary Sclerosing Cholangitis Including Transplantation

Primary sclerosing cholangitis is a progressive cholestatic liver disease that causes stricturing of the intra and extrahepatic bile ducts that can lead to cirrhosis and end stage liver disease. Effective medical therapy has been elusive, but a course of ursodeoxycholic acid may be prescribed at doses of 17-23 mg/kg/day for up to a year to determine if a reduction in serum alkaline phosphatase is observed. A number of drugs are under investigation, including FXR agonists with choleretic and antimicrobial properties. Liver transplantation for PSC has one of the highest survival rates, but recurrent PSC is seen in up to 25% of recipients.

Microbial Players in Primary Sclerosing Cholangitis: Current Evidence and Concepts

Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease with progressive biliary inflammation, destruction of the biliary tract, and fibrosis, resulting in liver cirrhosis and end-stage liver disease. To date, liver transplantation is the only definitive treatment option for PSC. The precise etiology of PSC remains elusive, but it is widely accepted to involve a complex interplay between genetic predisposition, immunologic dysfunction, and environmental influence. In recent years, the gut-liver axis has emerged as a crucial pathway contributing to the pathogenesis of PSC, with particular focus on the role of gut microbiota. However, the role of the fungal microbiome or mycobiome has been overlooked for years, resulting in a lack of comprehensive studies on its involvement in PSC. In this review, we clarify the present clinical and mechanistic data and concepts concerning the gut bacterial and fungal microbiota in the context of PSC. This review sheds light on the role of specific microbes and elucidates the dynamics of bacterial and fungal populations. Moreover, we discuss the latest insights into microbe-altering therapeutic approaches involving the gut-liver axis and bile acid metabolism.

Current insights on the roles of gut microbiota in inflammatory bowel disease-associated extra-intestinal manifestations: pathophysiology and therapeutic targets

Inflammatory bowel disease (IBD) is a chronic, recurrent inflammatory disease of the gastrointestinal tract. In addition to digestive symptoms, patients with IBD may also develop extra-intestinal manifestations (EIMs), the etiology of which remains undefined. The gut microbiota has been reported to exert a critical role in the pathogenesis of IBD, with a similar pattern of gut dysbiosis observed between patients with IBD and those with EIMs. Therefore, it is hypothesized that the gut microbiota is also involved in the pathogenesis of EIMs. The potential mechanisms are presented in this review, including: 1) impaired gut barrier: dysbiosis induces pore formation in the intestinal epithelium, and activates pattern recognition receptors to promote local inflammation; 2) microbial translocation: intestinal pathogens, antigens, and toxins translocate via the impaired gut barrier into extra-intestinal sites; 3) molecular mimicry: certain microbial antigens share similar epitopes with self-antigens, inducing inflammatory responses targeting extra-intestinal tissues; 4) microbiota-related metabolites: dysbiosis results in the dysregulation of microbiota-related metabolites, which could modulate the differentiation of lymphocytes and cytokine production; 5) immunocytes and cytokines: immunocytes are over-activated and pro-inflammatory cytokines are excessively released. Additionally, we summarize microbiota-related therapies, including probiotics, prebiotics, postbiotics, antibiotics, and fecal microbiota transplantation, to promote better clinical management of IBD-associated EIMs.

Current Therapeutics in Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is an orphan, cholestatic liver disease that is characterized by inflammatory biliary strictures with variable progression to end-stage liver disease. Its pathophysiology is poorly understood. Chronic biliary inflammation is likely driven by immune dysregulation, gut dysbiosis, and environmental exposures resulting in gut-liver crosstalk and bile acid metabolism disturbances. There is no proven medical therapy that alters disease progression in PSC, with the commonly prescribed ursodeoxycholic acid being shown to improve liver biochemistry at low-moderate doses (15-23 mg/kg/day) but not alter transplant-free survival or liver-related outcomes. Liver transplantation is the only option for patients who develop end-stage liver disease or refractory complications of PSC. Immunosuppressive and antifibrotic agents have not proven to be effective, but there is promise for manipulation of the gut microbiome with fecal microbiota transplantation and antibiotics. Bile acid manipulation via alternate synthetic bile acids such as norursodeoxycholic acid, or interaction at a transcriptional level via nuclear receptor agonists and fibrates have shown potential in phase II trials in PSC with several leading to larger phase III trials. In view of the enhanced malignancy risk, statins, and aspirin show potential for reducing the risk of colorectal cancer and cholangiocarcinoma in PSC patients. For patients who develop clinically relevant strictures with cholestatic symptoms and worsening liver function, balloon dilatation is safer compared with biliary stent insertion with equivalent clinical efficacy.

The Many Faces of Primary Sclerosing Cholangitis: Controversy Abounds

Primary sclerosing cholangitis (PSC) is notoriously challenging to manage given its heterogeneity with regard to diagnosis, management, and progression. The lack of disease-modifying therapy and variable rate of onset of cirrhosis, portal hypertension-related decompensating events, jaundice, pruritus, biliary complications, and need for liver transplantation is deeply unsettling to clinicians and patients alike. Recent updated practice guidance by the American Association for the Study of Liver Diseases and the European Association for the Study of the Liver endeavored to highlight some of these challenges. However, these references only briefly address clinical dilemmas that providers face on a daily basis. This review aims to further discuss these controversial topics, including providing insight into the utility of ursodeoxycolic acid, the significance of alkaline phosphatase normalization, when to consider PSC variants and mimickers, and the implications of continuous hepatobiliary malignancy screening. In particular, there has been a growing body of literature raising concern about repeat exposure to gadolinium-containing contrast. Patients with PSC are potentially at risk for large lifetime exposure to gadolinium related to frequent magnetic resonance imaging scans and whether this carries any negative long-term adverse effects remains unknown.

Role of microbiome in autoimmune liver diseases

The microbiome plays a crucial role in integrating environmental influences into host physiology, potentially linking it to autoimmune liver diseases, such as autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. All autoimmune liver diseases are associated with reduced diversity of the gut microbiome and altered abundance of certain bacteria. However, the relationship between the microbiome and liver diseases is bidirectional and varies over the course of the disease. This makes it challenging to dissect whether such changes in the microbiome are initiating or driving factors in autoimmune liver diseases, secondary consequences of disease and/or pharmacological intervention, or alterations that modify the clinical course that patients experience. Potential mechanisms include the presence of pathobionts, disease-modifying microbial metabolites, and more nonspecific reduced gut barrier function, and it is highly likely that the effect of these change during the progression of the disease. Recurrent disease after liver transplantation is a major clinical challenge and a common denominator in these conditions, which could also represent a window to disease mechanisms of the gut-liver axis. Herein, we propose future research priorities, which should involve clinical trials, extensive molecular phenotyping at high resolution, and experimental studies in model systems. Overall, autoimmune liver diseases are characterized by an altered microbiome, and interventions targeting these changes hold promise for improving clinical care based on the emerging field of microbiota medicine.

Gut Microbiota and Antibiotic Treatments for the Main Non-Oncologic Hepato-Biliary-Pancreatic Disorders

The gut microbiota is a pivotal actor in the maintenance of the balance in the complex interconnections of hepato-biliary-pancreatic system. It has both metabolic and immunologic functions, with an influence on the homeostasis of the whole organism and on the pathogenesis of a wide range of diseases, from non-neoplastic ones to tumorigenesis. The continuous bidirectional metabolic communication between gut and hepato-pancreatic district, through bile ducts and portal vein, leads to a continuous interaction with translocated bacteria and their products. Chronic liver disease and pancreatic disorders can lead to reduced intestinal motility, decreased bile acid synthesis and intestinal immune dysfunction, determining a compositional and functional imbalance in gut microbiota (dysbiosis), with potentially harmful consequences on the host's health. The modulation of the gut microbiota by antibiotics represents a pioneering challenge with striking future therapeutic opportunities, even in non-infectious diseases. In this setting, antibiotics are aimed at harmonizing gut microbial function and, sometimes, composition. A more targeted and specific approach should be the goal to pursue in the future, tailoring the treatment according to the type of microbiota modulation to be achieved and using combined strategies.

The microbiota and the gut-liver axis in primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) offers unique opportunities to explore the gut-liver axis owing to the close association between liver disease and colonic inflammation. It is well established that the gut microbiota in people with PSC differs from that of healthy individuals, but details of the microbial factors that demarcate PSC from inflammatory bowel disease (IBD) without PSC are poorly understood. In this Review, we aim to provide an overview of the latest literature on the gut microbiome in PSC and PSC with IBD, critically examining hypotheses on how microorganisms could contribute to the pathogenesis of PSC. A particular emphasis will be put on pathogenic features of the gut microbiota that might explain the occurrence of bile duct inflammation and liver disease in the context of IBD, and we postulate the potential existence of a specific yet unknown factor related to the gut-liver axis as causative in PSC. Available data are scrutinized in the perspective of therapeutic approaches related to the gut-liver axis.

Systematic review: microbial manipulation as therapy for primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is a progressive liver disease with poor prognosis and no effective therapies to prevent progression. An aetiopathological link between PSC and gastrointestinal microbial dysbiosis has been suggested.

AIM

To evaluate all potential medical therapies which may exert their effect in PSC by modulation of the gut-liver axis.

METHODS

We conducted a comprehensive scoping review of PubMed and Cochrane Library, including all articles evaluating an intervention aimed at manipulating the gastrointestinal microbiome in PSC.

RESULTS

A wide range of therapies proposed altering the gastrointestinal microbiome for the treatment of PSC. In particular, these considered antibiotics including vancomycin, metronidazole, rifaximin, minocycline and azithromycin. However, few therapies have been investigated in randomised, placebo-controlled trials. Vancomycin has been the most widely studied antibiotic, with improvement in alkaline phosphatase reported in two randomised controlled trials, but with no data on disease progression. Unlike antibiotics, strategies such as faecal microbiota transplantation and dietary therapy can improve microbial diversity. However, since these have only been tested in small numbers of patients, robust efficacy data are currently lacking.

CONCLUSIONS

The gut-liver axis is increasingly considered a potential target for the treatment of PSC. However, no therapies have been demonstrated to improve transplant-free survival. Innovative and well-designed clinical trials of microbiome-targeted therapies with long-term follow-up are required for this orphan disease.

Role of intestinal flora in primary sclerosing cholangitis and its potential therapeutic value

Primary sclerosing cholangitis (PSC) is an autoimmune disease characterized by chronic cholestasis, a persistent inflammation of the bile ducts that leads to sclerotic occlusion and cholestasis. Gut microbes, consisting of microorganisms colonized in the human gut, play an important role in nutrient intake, metabolic homeostasis, immune regulation, and immune regulation; however, their presence might aid PSC development. Studies have found that gut-liver axis interactions also play an important role in the pathogenesis of PSC. Patients with PSC have considerably reduced intestinal flora diversity and increased abundance of potentially pathogenic bacteria. Dysbiosis of the intestinal flora leads to increased intestinal permeability, homing of intestinal lymphocytes, entry of bacteria and their associated metabolites, such as bile acids, into the liver, stimulation of hepatic immune activation, and promotion of PSC. Currently, PSC effective treatment is lacking. However, a number of studies have recently investigated the targeted modulation of gut microbes for the treatment of various liver diseases (alcoholic liver disease, metabolic fatty liver, cirrhosis, and autoimmune liver disease). In addition, antibiotics, fecal microbiota transplantation, and probiotics have been reported as successful PSC therapies as well as for the treatment of gut dysbiosis, suggesting their effectiveness for PSC treatment. Therefore, this review briefly summarizes the role of intestinal flora in PSC with the aim of providing new insights into PSC treatment.

EASL Clinical Practice Guidelines on sclerosing cholangitis

Management of primary or secondary sclerosing cholangitis is challenging. These Clinical Practice Guidelines have been developed to provide practical guidance on debated topics including diagnostic methods, prognostic assessment, early detection of complications, optimal care pathways and therapeutic (pharmacological, endoscopic or surgical) options both in adults and children.

The Role of Gut Microbiota in Some Liver Diseases: From an Immunological Perspective

Gut microbiota is a microecosystem composed of various microorganisms. It plays an important role in human metabolism, and its metabolites affect different tissues and organs. Intestinal flora maintains the intestinal mucosal barrier and interacts with the immune system. The liver is closely linked to the intestine by the gut-liver axis. As the first organ that comes into contact with blood from the intestine, the liver will be deeply influenced by the gut microbiota and its metabolites, and the intestinal leakage and the imbalance of the flora are the trigger of the pathological reaction of the liver. In this paper, we discuss the role of gut microbiota and its metabolites in the pathogenesis and development of autoimmune liver diseases((including autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis), metabolic liver disease such as non-alcoholic fatty liver disease, cirrhosisits and its complications, and liver cancer from the perspective of immune mechanism. And the recent progress in the treatment of these diseases was reviewed from the perspective of gut microbiota.

The intestinal and biliary microbiome in autoimmune liver disease-current evidence and concepts

Autoimmune liver diseases are a group of immune-mediated liver diseases with three distinct entities, including autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. The interplay of genetic and environmental factors leads to the breakdown of self-tolerance, resulting in hyper-responsiveness, and auto-aggressive immune activation. Emerging evidence links autoimmune liver diseases with alterations of the commensal microbiome configuration and aberrant immune system activation by microbial signals, mainly via the gut-liver axis. Thus, the microbiome is a new frontier to deepen the pathogenetic understanding, uncover biomarkers, and inspire innovative treatments. Herein, we review the current evidence on the role of the microbiome in autoimmune liver diseases from both clinical and basic research. We highlight recent achievements and also bottlenecks and limitations. Moreover, we give an outlook on future developments and potential for clinical applications.

Treatment of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by progressive fibro-stenotic strictures and destruction of the biliary tree. Currently, there is no effective treatment which can delay its progression or ameliorate the transplant-free survival. Moreover, a major chontroversy in PSC is whether to use UDCA. More recently, novel pharmacological agents emerged aiming at: i) modulation of bile composition; ii) immunomodulation; iii) targeting the gut microbiome; iv) targeting fibrosis. Successful PSC therapy, however, will be most likely a personalized combination of different drugs plus endoscopic treatment. This review aims at offering an overview on the experimental pharmacological strategies currently exploited for PSC treatment.

The Role of Microbiota in Primary Sclerosing Cholangitis and Related Biliary Malignancies

Primary sclerosing cholangitis (PSC) is an immune-related cholangiopathy characterized by biliary inflammation, cholestasis, and multifocal bile duct strictures. It is associated with high rates of progression to end-stage liver disease as well as a significant risk of cholangiocarcinoma (CCA), gallbladder cancer, and colorectal carcinoma. Currently, no effective medical treatment with an impact on the overall survival is available, and liver transplantation is the only curative treatment option. Emerging evidence indicates that gut microbiota is associated with disease pathogenesis. Several studies analyzing fecal and mucosal samples demonstrate a distinct gut microbiome in individuals with PSC compared to healthy controls and individuals with inflammatory bowel disease (IBD) without PSC. Experimental mouse and observational human data suggest that a diverse set of microbial functions may be relevant, including microbial metabolites and bacterial processing of pharmacological agents, bile acids, or dietary compounds, altogether driving the intrahepatic inflammation. Despite critical progress in this field over the past years, further functional characterization of the role of the microbiota in PSC and related malignancies is needed. In this review, we discuss the available data on the role of the gut microbiome and elucidate important insights into underlying pathogenic mechanisms and possible microbe-altering interventions.

The Management of Cholestatic Liver Diseases: Current Therapies and Emerging New Possibilities

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are two chronic cholestatic liver diseases affecting bile ducts that may progress to biliary cirrhosis. In the past few years, the increasing knowledge in the pathogenesis of both diseases led to a growing number of clinical trials and possible new targets for therapy. In this review, we provide an update on the treatments in clinical use and summarize the new drugs in trials for PBC and PSC patients. Farnesoid X Receptor (FXR) agonists and Pan-Peroxisome Proliferator-Activated Receptor (PPAR) agonists are the most promising agents and have shown promising results in both PBC and PSC. Fibroblast Growth Factor 19 (FGF19) analogues also showed good results, especially in PBC, while, although PBC and PSC are autoimmune diseases, immunosuppressive drugs had disappointing effects. Since the gut microbiome could have a potential role in the pathogenesis of PSC, recent research focused on molecules that could change the microbiome, with good results. The near future of the medical management of these diseases may include new treatments or a combination of multiple drugs targeting different signaling pathways at different stages of the diseases.

Recent advances in the treatment of primary sclerosing cholangitis

Introduction: PSC is a rare liver disease that leads frequently to cirrhosis and need for liver transplantation. No medical treatment is of proven value. Liver transplantation is the only curative therapy available. There is a big medical need to find medical therapy that can alter the natural history of the disease.Areas covered: The authors highlight advances in PSC, based on recent literature retrieved from PubMed until September 2020 regarding both medical and endoscopic biliary therapy.Future possibilities for treatment of PSC are discussed.Expert opinion: Biliary endoscopy is the cornerstone in the treatment of dominant strictures. Single-user peroral cholangioscopy is an emerging modality. Balloon dilatation therapy is the treatment of choice of dominant strictures. The most promising medical therapies showing efficacy in phase II trials are nor-Ursodeoxycholic acid, obethicolic acid, the non-steroidal FXR agonist Cilofexor and Aldafermin, a synthetic analogue of FGF-19. Antibiotics, particularly vancomycin have shown potential benefits, particularly in children but phase III studies are lacking. In observational studies of effects of biological therapy in patients with IBD/PSC adalimumab was associated with reduction in ALP. Results of liver transplantation are favorable but recurrence can be of clinical relevance particularly in patients transplanted before the age of 40.

The Gut-Liver Axis in Cholestatic Liver Diseases

The gut-liver axis describes the physiological interplay between the gut and the liver and has important implications for the maintenance of health. Disruptions of this equilibrium are an important factor in the evolution and progression of many liver diseases. The composition of the gut microbiome, the gut barrier, bacterial translocation, and bile acid metabolism are the key features of this cycle. Chronic cholestatic liver diseases include primary sclerosing cholangitis, the generic term secondary sclerosing cholangitis implying the disease secondary sclerosing cholangitis in critically ill patients and primary biliary cirrhosis. Pathophysiology of these diseases is not fully understood but seems to be multifactorial. Knowledge about the alterations of the gut-liver axis influencing the pathogenesis and the outcome of these diseases has considerably increased. Therefore, this review aims to describe the function of the healthy gut-liver axis and to sum up the pathological changes in these cholestatic liver diseases. The review compromises the actual level of knowledge about the gut microbiome (including the mycobiome and the virome), the gut barrier and the consequences of increased gut permeability, the effects of bacterial translocation, and the influence of bile acid composition and pool size in chronic cholestatic liver diseases. Furthermore, therapeutic implications and future scientific objectives are outlined.

Oral Vancomycin, Ursodeoxycholic Acid, or No Therapy for Pediatric Primary Sclerosing Cholangitis: A Matched Analysis

BACKGROUND AND AIMS

Many children with primary sclerosing cholangitis (PSC) receive oral vancomycin therapy (OVT) or ursodeoxycholic acid (UDCA). There is a paucity of data on whether these medications improve outcomes.

APPROACH AND RESULTS

We analyzed retrospective data from the Pediatric PSC Consortium. Children treated with OVT were matched 1:1:1 to those treated with UDCA or managed with observation (no treatment) based on the closest propensity score, ensuring similar baseline characteristics. Two hundred sixty-four patients (88 each with OVT, UDCA, or observation) had matching propensity scores and were similar in demographics, phenotype, immunosuppression, baseline biochemistry, and hepatic fibrosis. After 1 year in an intention-to-treat analysis, all outcome metrics were similar regardless of treatment group. In OVT, UDCA, and untreated groups, respectively: Gamma-glutamyltransferase normalized in 53%, 49%, and 52% (P = not significant [NS]), liver fibrosis stage was improved in 20%, 13%, and 18% and worsened in 11%, 29%, and 18% (P = NS), and the 5-year probability of liver transplant listing was 21%, 10%, and 12% (P = NS). Favorable outcome was associated with having a mild phenotype of PSC and minimal hepatic fibrosis.

CONCLUSIONS

We presented the largest-ever description of outcomes on OVT in PSC and compared them to carefully matched patients on UDCA or no therapy. Neither OVT nor UDCA showed improvement in outcomes compared to a strategy of observation. Patients progressed to end-stage liver disease at similar rates. Spontaneous normalization of biochemistry is common in children receiving no therapy, particularly in the majority of children with a mild phenotype and an early stage of disease. Placebo-controlled treatment trials are needed to identify effective treatments for pediatric PSC.

Multiple therapeutic targets in rare cholestatic liver diseases: Time to redefine treatment strategies

Primary biliary cholangitis and primary sclerosing cholangitis are rare diseases affecting the bile ducts and the liver. The limited knowledge of their pathogenesis leads to limited therapeutic options. Nevertheless, the landscape of novel therapies for these cholangiopathies is now rapidly changing, providing new treatment opportunities for patients and clinicians involved in their care. The aim of this review is to summarize the evidence of novel molecules under investigation for primary biliary cholangitis and primary sclerosing cholangitis and to discuss how they can potentially change current treatment paradigms.

Targeting the Gut Microbiome as a Treatment for Primary Sclerosing Cholangitis: A Conceptional Framework

Primary sclerosing cholangitis (PSC) is a rare, immune-mediated, chronic cholestatic liver disease associated with a unique phenotype of inflammatory bowel disease that frequently manifests as pancolitis with right-sided predominance. Available data suggest a bidirectional interplay of the gut-liver axis with critical roles for the gastrointestinal microbiome and circulating bile acids (BAs) in the pathophysiology of PSC. BAs shape the gut microbiome, whereas gut microbes have the potential to alter BAs, and there are emerging data that alterations of BAs and the microbiome are not simply a consequence but the cause of PSC. Clustering of PSC in families may suggest that PSC occurs in genetically susceptible individuals. After exposure to an environmental trigger (e.g., microbial byproducts or BAs), an aberrant or exaggerated cholangiocyte-induced immune cascade occurs, ultimately leading to bile duct damage and progressive fibrosis. The pathophysiology can be conceptualized as a triad of (1) gut dysbiosis, (2) altered BA metabolism, and (3) immune-mediated biliary injury. Immune activation seems to be central to the disease process, but immunosuppression does not improve clinical outcomes or alter the natural history of PSC. Currently, orthoptic liver transplantation is the only established life-saving treatment, whereas antimicrobial therapy or fecal transplantation is an emerging therapeutic option for PSC. The beneficial effects of these microbiome-based therapies are likely mediated by a shift of the gut microbiome with favorable effects on BA metabolism. In the future, personalized approaches will allow to better target the interdependence between microbiome, immune function, and BA metabolism and potentially cure patients with PSC.

New Therapeutic Targets in Autoimmune Cholangiopathies

Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are autoimmune cholangiopathies characterized by limited treatment options. A more accurate understanding of the several pathways involved in these diseases has fostered the development of novel and promising targeted drugs. For PBC, the characterization of the role of farnesoid X receptor (FXR) and perixosome-proliferator activated receptor (PPAR) has paved the way to several clinical trials including different molecules with choleretic and antinflammatory action. Conversely, different pathogenetic models have been proposed in PSC such as the “leaky gut” hypothesis, a dysbiotic microbiota or a defect in mechanisms protecting against bile acid toxicity. Along these theories, new treatment approaches have been developed, ranging from drugs interfering with trafficking of lymphocytes from the gut to the liver, fecal microbiota transplantation or new biliary acids with possible immunomodulatory potential. Finally, for both diseases, antifibrotic agents are under investigation. In this review, we will illustrate current understanding of molecular mechanisms in PBC and PSC, focusing on actionable biological pathways for which novel treatments are being developed.

Drug Therapies for Chronic Cholestatic Liver Diseases

Though ursodeoxycholic acid (UDCA) remains the baseline treatment for most cholestatic liver diseases, UDCA treatment leaves approximately one-third of patients with primary biliary cholangitis (PBC) and all patients with primary sclerosing cholangitis (PSC) at risk for disease progression. New anticholestatic agents, including nuclear receptor agonists, choleretics, and bile acid synthesis suppressors, will likely increase response rates to therapy in PBC and PSC. Strategies that target early immune-mediated injury have so far been disappointing, hampered by the lack of biomarkers to detect early disease states, which then could profit from immunomodulatory therapy. Future concepts need to personalize treatments according to disease stage, progression, and phase, and to combine multiple drugs to target different pathogenic pathways.

Consensus guidelines: best practices for detection, assessment and management of suspected acute drug-induced liver injury occurring during clinical trials in adults with chronic cholestatic liver disease

BACKGROUND

Improved knowledge of the molecular pathophysiology and immunopathogenesis of cholestatic liver diseases in recent years has led to an increased interest in developing novel therapies. Patients with cholestatic liver disease often require different approaches to assessment and management of suspected drug-induced liver injury (DILI) compared to those with healthy livers and those with parenchymal liver diseases. At present, there are no regulatory guidelines or society position papers, that systematically address best practices pertaining to detection of DILI in these patients.

AIMS

To outline best practices for detection, assessment and management of suspected acute DILI during clinical trials in adults with the cholestatic liver diseases - Primary Biliary Cholangitis (PBC) and Primary Sclerosing Cholangitis (PSC).

METHODS

This is one of the several papers developed by the IQ DILI Initiative, which is comprised of members from 16 pharmaceutical companies, in collaboration with DILI experts from academia and regulatory agencies. The contents are the result of an extensive literature review, as well as in-depth discussions among industry, regulatory and academic DILI experts, to achieve consensus recommendations on DILI-related issues occurring during clinical trials for cholestatic liver diseases.

RESULTS

Recommended best practices are outlined pertaining to hepatic eligibility criteria, monitoring of liver tests, approach to a suspected DILI signal, and hepatic discontinuation rules.

CONCLUSIONS

This paper provides a framework for the approach to detection, assessment and management of suspected acute DILI occurring during clinical trials in adults with cholestatic liver disease.

Emerging therapies in primary sclerosing cholangitis: pathophysiological basis and clinical opportunities

Primary sclerosing cholangitis (PSC) is a progressive liver disease, histologically characterized by inflammation and fibrosis of the bile ducts, and clinically leading to multi-focal biliary strictures and with time cirrhosis and liver failure. Patients bear a significant risk of cholangiocarcinoma and colorectal cancer, and frequently have concomitant inflammatory bowel disease and autoimmune disease manifestations. To date, no medical therapy has proven significant impact on clinical outcomes and most patients ultimately need liver transplantation. Several treatment strategies have failed in the past and whilst prescription of ursodeoxycholic acid (UDCA) prevails, controversy regarding benefits remains. Lack of statistical power, slow and variable disease progression, lack of surrogate biomarkers for disease severity and other challenges in trial design serve as critical obstacles in the development of effective therapy. Advances in our understanding of PSC pathogenesis and biliary physiology over recent years has however led to a surge of clinical trials targeting various mechanistic compartments and currently raising hopes for imminent changes in patient management. Here, in light of pathophysiology, we outline and critically evaluate emerging treatment strategies in PSC, as tested in recent or ongoing phase II and III trials, stratified per a triad of targets of nuclear and membrane receptors regulating bile acid metabolism, immune modulators, and effects on the gut microbiome. Furthermore, we revisit the UDCA trials of the past and critically discuss relevant aspects of clinical trial design, including how the choice of endpoints, alkaline phosphatase in particular, may affect the future path to novel, effective PSC therapeutics.

Primary Sclerosing Cholangitis: A Clinical Update

Primary sclerosing cholangitis (PSC) is a rare cholestatic disorder of the liver, with strictures in the bile ducts leading to cirrhosis of the liver in a proportion of patients. PSC is commonly associated with inflammatory bowel disease and increased risk of cholangiocarcinoma, gall bladder cancer, colorectal cancer, and hepatocellular carcinoma. Medical therapies are primarily aimed at symptom management and disease-modifying therapies are limited. Endoscopic therapies are used in patients with dominant strictures and liver transplantation is a last resort. In this article, the authors aim to comprehensively review the epidemiology, diagnosis, and management of PSC with emphasis on risk of malignancies and management of PSC. The authors also survey the advances in pathogenesis understanding and novel medical therapies for PSC.

Pharmacologic management of primary sclerosing cholangitis: what's in the pipeline?

Introduction: Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease characterized by biliary inflammation, fibrosis, and stricturing. Although considered progressive, its course is difficult to predict, and there is currently no definitive therapy shown to alter disease course and prevent death or the need for liver transplantation. Areas covered: There are multiple agents in the pipeline targeting various pathways hypothesized to lead to and drive this disease. Some are already used for other treatment indications, including antibiotics such as oral vancomycin, metronidazole, and minocycline. Other agents including obeticholic acid, nor-ursodeoxycholic acid, and monoclonal antibodies are also under investigation. This narrative review focuses on the most recent published clinical trials available for discussion. We attempt to summarize the data on current and future treatment options. Expert opinion: The rarity of this condition and poor understanding of its pathophysiology have created a void for safe and effective treatment options to alter mortality or transplant free survival. Nevertheless, some agents currently being tested have demonstrated therapeutic potential. We await validation and prospective data on these agents in hopes of modifying the disease course for patients in the future.

Preventative care in cholestatic liver disease: Pearls for the specialist and subspecialist

Cholestatic liver diseases (CLDs) encompass a variety of disorders of abnormal bile formation and/or flow. CLDs often lead to progressive hepatic insult and injury and following the development of cirrhosis and associated complications. Many such complications are clinically silent until they manifest with severe sequelae, including but not limited to life-altering symptoms, metabolic disturbances, cirrhosis, and hepatobiliary diseases as well as other malignancies. Primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC) are the most common CLDs, and both relate to mutual as well as unique complications. This review provides an overview of PSC and PBC, with a focus on preventive measures aimed to reduce the incidence and severity of disease-related complications.

Treatment of primary sclerosing cholangitis in children

Primary sclerosing cholangitis (PSC) is a rare disease of stricturing and destruction of the biliary tree with a complex genetic and environmental etiology. Most patients have co-occurring inflammatory bowel disease. Children generally present with uncomplicated disease, but undergo a variable progression to end-stage liver disease. Within ten years of diagnosis, 50% of children will develop clinical complications including 30% requiring liver transplantation. Cholangiocarcinoma is a rare but serious complication affecting 1% of children. Ursodeoxycholic acid and oral vancomycin therapy used widely in children as medical therapy, and may be effective in a subset of patients. Gamma glutamyltransferase is a potential surrogate endpoint for disease activity, with improved survival in patients who achieve a normal value. Endoscopic retrograde cholangiopancreatography is a necessary adjunct to medical therapy to evaluate mass lesions or dominant strictures for malignancy, and also to relieve biliary obstruction. Liver transplantation remains the only option for patients who progress to end-stage liver disease. We review special considerations for patients before and after transplant, and in patients with inflammatory bowel disease. There is presently no published treatment algorithm or guideline for the management of children with PSC. We review the evidence for drug efficacy, dosing, duration of therapy, and treatment targets in PSC, and provide a framework for endoscopic and medical management of this complex problem.

Autoimmune Liver Diseases in Children

Autoimmune liver disease remains difficult to diagnose, and distinguishing the various causes is difficult as well. In children, it can present with wide variation, including autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC), and the "overlap syndrome" of AIH/PSC, also known as autoimmune sclerosing cholangitis. These liver disorders are thought to be immune-mediated, but their etiology remains unclear. They are not secondary to inherited or acquired diseases and they are not associated with any drugs, so they can only be diagnosed if these other diseases or conditions are excluded. Because there is considerable commonality in the clinical presentation of these diseases but differences in their management, appropriate treatment may be delayed, increasing the risk for liver transplantation. Further education for general pediatricians and trainees is needed. This article reviews the differences between AIH and PSC, as well as the newly recognized overlap syndrome of both of these diseases. [Pediatr Ann. 2018;47(11):e452-e457.].

Novel and emerging therapies for cholestatic liver diseases

While bile acids are important for both digestion and signalling, hydrophobic bile acids can be harmful, especially when in high concentrations. Mechanisms for the protection of cholangiocytes against bile acid cytotoxicity include negative feedback loops via farnesoid X nuclear receptor (FXR) activation, the bicarbonate umbrella, cholehepatic shunting and anti-inflammatory signalling, among others. By altering or overwhelming these defence mechanisms, cholestatic diseases such as primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) can further progress to biliary cirrhosis, end-stage liver disease and death or liver transplantation. While PBC is currently treated with ursodeoxycholic acid (UDCA) and obeticholic acid (OCA), many fail treatment, and we have yet to find an effective therapy for PSC. Novel therapies under evaluation target nuclear and surface receptors including FXR, transmembrane G-protein-coupled receptor 5 (TGR5), peroxisome proliferator-activated receptor (PPAR) and pregnane X receptor (PXR). Modulation of these receptors leads to altered bile composition, decreased cytotoxicity, decreased inflammation and improved metabolism. This review summarizes our current understanding of the role of bile acids in the pathophysiology of cholestatic liver diseases, presents the rationale for already approved medical therapies and discusses novel pharmacologic therapies under investigation.

Cholestatic liver diseases: new targets, new therapies

Cholestatic liver diseases result from gradual destruction of bile ducts, accumulation of bile acids and self-perpetuation of the inflammatory process leading to damage to cholangiocytes and hepatocytes. If left untreated, cholestasis will lead to fibrosis, biliary cirrhosis, and ultimately end-stage liver disease. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are the two most common chronic cholestatic liver diseases affecting adults, and their etiologies remain puzzling. While treatment with ursodeoxycholic acid (UDCA) has significantly improved outcomes and prolonged transplant-free survival for patients with PBC, treatment options for UDCA nonresponders remain limited. Furthermore, there is no available medical therapy for PSC. With recent advances in molecular biochemistry specifically related to bile acid regulation and understanding of immunologic pathways, novel pharmacologic treatments have emerged. In this review, we discuss the standard of care and emphasize the various emerging treatments for PBC and PSC.

Update in the Care and Management of Patients with Primary Sclerosing Cholangitis

PURPOSE OF REVIEW

Primary sclerosing cholangitis (PSC) is a progressive cholestatic liver disease for which specific medical therapy is not available. The goals of treatment are primarily early detection and management of complications. In this review, we discuss novel therapies under evaluation and provide the foundation for surveillance strategies.

RECENT FINDINGS

Drugs under investigation include norursodeoxycholic acid, nuclear receptor agonists, anti-fibrotics, antibiotics, and anti-inflammatory drugs. Endoscopic therapy is indicated for symptomatic dominant strictures and in the work-up of malignancies. Recently, the use of stents was associated with an increased rate of complications compared to balloon dilatation; and long-term stenting should be avoided. Malignancies currently account for most of the PSC-related mortality. Many drugs are emerging for the treatment of PSC but liver transplantation is the only treatment modality shown to prolong survival. PSC recurrence occurs in up to 35% of transplanted allografts within a median of 5 years. Surveillance for hepatobiliary and colorectal malignancies is indicated.

Autoimmune liver disease and the enteric microbiome

The human enteric microbiome is highly complex and has more than 150 times more genes within it than its host. The host and the microbiome have a commensurate relationship that can evolve over time. The typically symbiotic relationship between the two can become pathogenic. The microbiome composition in adults reflects their history of exposure to bacteria and environmental factors during early life, their genetic background, age, interactions with the immune system, geographical location, and, most especially, their diet. Similarly, these factors are thought to contribute to the development of autoimmune disease. It is possible that alterations in the intestinal microbiome could lead to liver disease. There is emerging data for the contribution of the microbiome in development of primary sclerosing cholangitis, primary biliary cholangitis, and autoimmune hepatitis; liver disorders associated with aberrant immune function in genetically susceptible individuals.

Dysbiosis of the salivary microbiota in pediatric-onset primary sclerosing cholangitis and its potential as a biomarker. Sci Rep. 2018;8:5480. [PMID: 29615776 PMCID: PMC5882660 DOI: 10.1038/s41598-018-23870-w]

Primary sclerosing cholangitis (PSC) is a liver disease known for its frequent concurrence with inflammatory bowel disease. Dysbiosis of the gut microbiota in PSC was reported in several studies, but the microbiological features of the salivary microbiota in PSC have not been established. Here we compared the salivary microbial communities of 24 pediatric-onset PSC patients, 16 age-matched ulcerative colitis (UC) patients, and 24 healthy controls (HCs) by analyzing the bacterial 16S rRNA gene sequence data. The species-richness (α-diversity) showed no significant between-group differences, whereas the overall salivary microbiota structure (β-diversity) showed significant differences among the three groups. Taxonomic assignment revealed that the PSC salivary microbiota were characterized by significant decreases in the abundance of Rothia and Haemophilus compared to the HC group, and significantly decreased Haemophilus and increased Oribacterium compared to the UC group. By combining the genera selected by the random forest algorithm in machine learning, followed by confirmation with 10-fold cross-validation, we were able to distinguish the PSC group from the HC group with the area under the curve (AUC) of 0.7423, and from the UC group with the AUC of 0.8756. Our results indicate the potential of salivary microbiota as biomarkers for a noninvasive diagnosis of PSC.

Review article: the evidence that vancomycin is a therapeutic option for primary sclerosing cholangitis

BACKGROUND AND AIMS

PSC is an autoimmune biliary inflammatory disorder that is often associated with inflammatory bowel disease (IBD), with 50%-75% of patients with PSC having coexisting IBD, most commonly ulcerative colitis. Currently, no medical therapies have been shown to improve the disease course or slow its progression. However, ongoing research has resulted in a growing interest in the use of antibiotics for treatment of PSC, of which vancomycin is the most studied. In this review, we summarise the current evidence on the use of vancomycin in PSC and comment on future research areas of interest.

METHODS

A comprehensive PUBMED and EMBASE literature search for articles on vancomycin, PSC, therapeutic options and microbiome was performed.

RESULTS

Two randomised clinical trials, three case series and two case reports were included in the study. These include uncontrolled data from at least 98 patients that include promising improvements in biochemistry and imaging. Optimal dosing regimens are unclear.

CONCLUSION

Vancomycin is one of the most studied antibiotics used in the treatment of PSC with promising results. There is not currently sufficient evidence to support treatment recommendations. Further research is needed to establish if vancomycin is a PSC treatment.

Searching for Bacterial Biofilm in Recurrent Cholangitis in Primary Sclerosing Cholangitis: A Case Presentation and Introduction of an Unexplored Disease Mechanism

Inflammation and fibrosis of the bile ducts are the defining pathological characteristics of primary sclerosing cholangitis (PSC). A previously unexplored mechanism for recurrent cholangitis, one of PSC's most common presentations, is bacterial colonization of the biliary epithelium in the form of biofilm, which may confer resistance to antibiotics and host phagocytic machinery. The aim of the current study was to assess whether bacteria could be seen on the liver explant and whether they organized in the form of biofilm. An explanted PSC liver from a 60-year-old male who suffered from recurrent cholangitis was formalin-fixed, paraffin-embedded and Gram stained. The specimens were observed under light microscopy. Neither bacteria nor biofilm were detected. We did not detect bacteria or biofilm in the liver explant of a single PSC patient with recurrent cholangitis using standard light microscopy. We suspect this may be in part due to techniques related to tissue preservation and microscopy.

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.

Primary sclerosing cholangitis: A review and update

Primary sclerosing cholangitis (PSC) is a rare, chronic, cholestatic liver disease of uncertain etiology characterized biochemically by cholestasis and histologically and cholangiographically by fibro-obliterative inflammation of the bile ducts. In a clinically significant proportion of patients, PSC progresses to cirrhosis, end-stage liver disease, and/or hepatobiliary cancer, though the disease course can be highly variable. Despite clinical trials of numerous pharmacotherapies over several decades, safe and effective medical therapy remains to be established. Liver transplantation is an option for select patients with severe complications of PSC, and its outcomes are generally favorable. Periodic surveillance testing for pre- as well as post-transplant patients is a cornerstone of preventive care and health maintenance. Here we provide an overview of PSC including its epidemiology, etiopathogenesis, clinical features, associated disorders, surveillance, and emerging potential therapies.

Primary sclerosing cholangitis: diagnostic and management challenges

Primary sclerosing cholangitis (PSC) is a chronic immune-mediated disease affecting intra- and extrahepatic bile ducts, primarily the large biliary ducts. Clinical manifestations are broad, and the spectrum encompasses asymptomatic cholestasis, icteric cholangitis with pruritis, cirrhosis, and cholangiocarcinoma. Though rare, PSC has a propensity to affect young to middle-aged males and is strongly associated with inflammatory bowel disease. There is an unmet need for effective medical treatments for PSC, and to date, the only curative therapy is liver transplantation reserved for those with end-stage liver disease. This article addresses the diagnostic and management challenges of PSC, with a succinct analysis of existing therapies, their limitations, and a glimpse into the future of the management of this multifaceted pathologic entity.

Bile acids and intestinal microbiota in autoimmune cholestatic liver diseases. Autoimmun Rev. 2017;16:885-896. [PMID: 28698093 DOI: 10.1016/j.autrev.2017.07.002]

Autoimmune cholestatic liver diseases, including primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), are manifested as an impairment of normal bile flow and excessive accumulation of potentially toxic bile acids. Endogenous bile acids are involved in the pathogenesis and progression of cholestasis. Consequently, chronic cholestasis affects the expression of bile acid transporters and nuclear receptors, and results in liver injury. Several lines of evidence suggest that intestinal microbiota plays an important role in the etiopathogenesis of cholestatic liver diseases by regulating metabolism and immune responses. However, progression of the disease may also affect the composition of gut microbiota, which in turn exacerbates the progression of cholestasis. In addition, the interaction between intestinal microbiota and bile acids is not unidirectional. Bile acids can shape the gut microbiota community, and in turn, intestinal microbes are able to alter bile acid pool. In general, gut microbiota actively communicates with bile acids, and together play an important role in the pathogenesis of PBC and PSC. Targeting the link between bile acids and intestinal microbiota offers exciting new perspectives for the treatment of those cholestatic liver diseases. This review highlights current understanding of the interactions between bile acids and intestinal microbiota and their roles in autoimmune cholestatic liver diseases. Further, we postulate a bile acids-intestinal microbiota-cholestasis triangle in the pathogenesis of autoimmune cholestatic liver diseases and potential therapeutic strategies by targeting this triangle.

Emerging pharmacologic therapies for primary sclerosing cholangitis

PURPOSE OF REVIEW

The only currently approved treatment for primary sclerosing cholangitis (PSC) is liver transplantation, with a median time to transplant of 12-18 years after diagnosis. There are a number of emerging drugs that have the potential to meet this critically unmet need that will be summarized and discussed herein.

RECENT FINDINGS

Although the cause of PSC is unknown, there are a number of novel therapeutics under development. These drugs target presumed pathogenic mechanisms largely extrapolated from ex-vivo and in-vivo preclinical models, as well as translational observations.

SUMMARY

Future therapeutic strategies for PSC may include a multitude of complex pathogenic mechanisms encompassing pathways of immunomodulation, the microbiome and inflammation-related fibrosis.