Primary sclerosing cholangitis: a review and update on therapeutic developments

Potential Role of Inflammation-Promoting Biliary Microbiome in Primary Sclerosing Cholangitis and Cholangiocarcinoma

Background: Primary sclerosing cholangitis (PSC) is a major risk factor for cholangiocarcinoma (CCA). We investigated biliary and fecal microbiota to determine whether specific microbes in the bile or stool are associated with PSC or CCA. Methods: Bile was obtained from 32 patients with PSC, 23 with CCA with PSC, 26 with CCA without PSC, and 17 controls. Over 90% of bile samples were from patients with perihilar CCA. Stool was obtained from 31 patients with PSC (11 were matched to bile), 16 with CCA with PSC (10 matched to bile), and 11 with CCA without PSC (6 matched to bile). Microbiota composition was assessed using 16SrRNA-marker-based sequencing and was compared between groups. Results: Bile has a unique microbiota distinguished from negative DNA controls and stool. Increased species richness and abundance of Fusobacteria correlated with duration of PSC and characterized the biliary microbiota in CCA. Stool microbiota composition showed no significant differences between groups. Conclusions: We identified a unique microbial signature in the bile of patients with increased duration of PSC or with CCA, suggesting a role for microbiota-driven inflammation in the pathogenesis and or progression to perihilar CCA. Further studies are needed to test this hypothesis.

Allergic manifestations in autoimmune gastrointestinal disorders

Allergic disorders target a young population, are increasing in both incidence and prevalence and are associated with significant disease burden. They result from the complex interplay between (epi)genetic and environmental factors, resulting in a Th2 inflammatory process targeting the epithelium of the respiratory tract (allergic rhinitis and asthma), skin (atopic dermatitis), and gastrointestinal tract (food allergy). Although the exact pathogenic mechanisms remain elusive, an altered immune system response in the gut is increasingly recognized as a relevant step. Allergic and gastrointestinal autoimmune disorders share several epidemiological, pathogenic and risk factors and several treatment modalities. Here we revise the current literature and show that allergic disorders are highly prevalent in gastrointestinal autoimmune diseases, including celiac disease, inflammatory bowel disease, autoimmune pancreatitis, and autoimmune cholangiopathies. No data are available for some autoimmune diseases, such as autoimmune gastritis and autoimmune enteropathy. To ensure the comprehensive care of patients with autoimmune gastrointestinal disorders, along with disease-specific factors, the presence of allergic disorders should be evaluated and treated when present, possibly targeting shared molecular pathways. Future studies are needed to define the exact pathogenic mechanisms underpinning the association between allergic and autoimmune diseases of the gastrointestinal tract.

Cholangiocarcinoma in patients with primary sclerosing cholangitis

PURPOSE OF REVIEW

Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease characterized by progressive fibroinflammatory destruction of the intrahepatic and/or extrahepatic bile ducts. It is associated with a significantly increased risk of malignancy, particularly cholangiocarcinoma (CCA). In this review, we discuss what is currently known about the epidemiology of and risk factors for CCA in PSC as well as recent advances in its prevention, diagnosis, and surveillance.

RECENT FINDINGS

An area of major focus has been finding novel biomarkers (in serum, bile, and urine) for CCA. With the advancement of computing power, metabolomic and proteomic approaches, among other methods, may provide enhanced capability for differentiating between benign and malignant bile duct disease. Another area of focus has been the approach to CCA surveillance in PSC; a recent study has found that CCA surveillance in patients with PSC is associated with improved outcomes, including increased survival, thus advocating for its importance.

SUMMARY

Despite ongoing advancements in the study of PSC-associated CCA, early diagnosis of CCA remains difficult, treatment options are limited, and prognosis is often consequently poor. Continued research in the development of high-accuracy diagnostic tools, novel biomarkers, and surveillance techniques may help to increase the likelihood of diagnosing CCA at earlier stages, when therapeutic options have the highest likelihood of resulting in cure.

The transcription factor ETS1 promotes apoptosis resistance of senescent cholangiocytes by epigenetically up-regulating the apoptosis suppressor BCL2L1

Primary sclerosing cholangitis (PSC) is an idiopathic, progressive cholangiopathy. Cholangiocyte senescence is important in PSC pathogenesis, and we have previously reported that senescence is regulated by the transcription factor ETS proto-oncogene 1 (ETS1) and associated with overexpression of BCL2 like 1 (BCL2L1 or BCL-xL), an anti-apoptotic BCL2-family member. Here, we further explored the mechanisms regulating BCL-xL-mediated, apoptosis resistance in senescent cholangiocytes and uncovered that ETS1 and the histone acetyltransferase E1A-binding protein P300 (EP300 or p300) both promote BCL-xL transcription. Using immunofluorescence, we found that BCL-xL protein expression is increased both in cholangiocytes of livers from individuals with PSC and a mouse model of PSC. Using an in vitro model of lipopolysaccharide-induced senescence in normal human cholangiocytes (NHCs), we found increased BCL-xL mRNA and protein levels, and ChIP-PCRs indicated increased occupancy of ETS1, p300, and histone 3 Lys-27 acetylation (H3K27Ac) at the BCL-xL promoter. Using co-immunoprecipitation and proximity ligation assays, we further demonstrate that ETS1 and p300 physically interact in senescent but not control NHCs. Additionally, mutagenesis of predicted ETS1-binding sites within the BCL-xL promoter blocked luciferase reporter activity, and CRISPR/Cas9-mediated genetic deletion of ETS1 reduced senescence-associated BCL-xL expression. In senescent NHCs, TRAIL-mediated apoptosis was reduced ∼70%, and ETS1 deletion or RNAi-mediated BCL-xL suppression increased apoptosis. Overall, our results suggest that ETS1 and p300 promote senescent cholangiocyte resistance to apoptosis by modifying chromatin and inducing BCL-xL expression. These findings reveal ETS1 as a central regulator of both cholangiocyte senescence and the associated apoptosis-resistant phenotype.

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.

Biliary endoscopy in the management of primary sclerosing cholangitis and its complications

Primary sclerosing cholangitis (PSC) is a chronic, idiopathic, cholestatic liver disease characterized by inflammation and fibrosis of the intrahepatic and/or extrahepatic bile ducts. It can affect individuals of all age groups and gender, has no established pharmacotherapy, and is associated with a variety of neoplastic (e.g. cholangiocarcinoma) and non-neoplastic (e.g. dominant strictures) hepatobiliary complications. Given these considerations, endoscopy plays a major role in the care of patients with PSC. In this review, we discuss and provide updates regarding endoscopic considerations in the management of hepatobiliary manifestations and complications of PSC. Where evidence is limited, we suggest pragmatic approaches based on currently available data and expert opinion.

Gut microbiota in liver disease: too much is harmful, nothing at all is not helpful either

The intestinal microbiome plays a major role in the pathogenesis of liver disease, with a hallmark event being dysbiosis, or an imbalance of pathobionts and beneficial bacteria with the associated deleterious effects on their host. Reducing the number of intestinal bacteria with antibiotic treatment is generally advantageous in experimental liver diseases. Complete absence of intestinal microbiota as in germ-free rodents can be protective in autoimmune hepatitis and hepatic tumors induced by chemicals, or it can exacerbate disease as in acute toxic liver injury and liver fibrosis/cirrhosis. In alcoholic liver disease, nonalcoholic fatty liver disease, and autoimmune cholangiopathies, germ-free status can be associated with worsened or improved hepatic phenotype depending on the experimental model and type of rodent. Some of the unexpected outcomes can be explained by the limitations of rodents raised in a germ-free environment including a deficient immune system and an altered metabolism of lipids, cholesterol, xenobiotics/toxins, and bile acids. Given these limitations and to advance understanding of the interactions between host and intestinal microbiota, simplified model systems such as humanized gnotobiotic mice, or gnotobiotic mice monoassociated with a single bacterial strain or colonized with a defined set of microbes, are unique and useful models for investigation of liver disease in a complex ecosystem.

Cancer risk in primary sclerosing cholangitis: Epidemiology, prevention, and surveillance strategies

Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease characterized by progressive fibroinflammatory destruction of the intra- and/or extrahepatic biliary ducts. While its features and disease course can be variable, most patients with PSC have concurrent inflammatory bowel disease and will eventually develop liver cirrhosis and end-stage liver disease, with liver transplantation representing the only potentially curative option. Importantly, PSC is associated with a significantly increased risk of malignancy compared to the general population, mainly cholangiocarcinoma, gallbladder carcinoma, hepatocellular carcinoma, and colorectal cancer, with nearly 50% of deaths in patients with PSC being due to cancer. Therefore, robust surveillance strategies are needed, though uncertainty remains regarding how to best do so. In this review, we discuss the epidemiology, prevention, and surveillance of cancers in patients with PSC. Where evidence is limited, we present pragmatic approaches based on currently available data and expert opinion.

Current therapies and novel approaches for biliary diseases

Chronic liver diseases that inevitably lead to hepatic fibrosis, cirrhosis and/or hepatocellular carcinoma have become a major cause of illness and death worldwide. Among them, cholangiopathies or cholestatic liver diseases comprise a large group of conditions in which injury is primarily focused on the biliary system. These include congenital diseases (such as biliary atresia and cystic fibrosis), acquired diseases (such as primary sclerosing cholangitis and primary biliary cirrhosis), and those that arise from secondary damage to the biliary tree from obstruction, cholangitis or ischaemia. These conditions are associated with a specific pattern of chronic liver injury centered on damaged bile ducts that drive the development of peribiliary fibrosis and, ultimately, biliary cirrhosis and liver failure. For most, there is no established medical therapy and, hence, these diseases remain one of the most important indications for liver transplantation. As a result, there is a major need to develop new therapies that can prevent the development of chronic biliary injury and fibrosis. This mini-review briefly discusses the pathophysiology of liver fibrosis and its progression to cirrhosis. We make a special emphasis on biliary fibrosis and current therapeutic options, such as angiotensin converting enzyme-2 (known as ACE2) over-expression in the diseased liver as a novel potential therapy to treat this condition.

Oral vancomycin induces sustained deep remission in adult patients with ulcerative colitis and primary sclerosing cholangitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease of unknown etiology. The treatment of UC is challenging, especially when it is associated with primary sclerosing cholangitis (PSC), a chronic inflammatory disease of the bile ducts that affects around 5% of patients with UC, and leads to an increased risk of cholangiocarcinoma and colorectal cancer. Microbiota is considered to play an important role in the pathogenesis of UC, although the efficacy of antibiotics in this context is only limited and transient. Several studies have investigated the use of antibiotics for the treatment of PSC in adult and pediatric populations, with conflicting results. In this brief report, we describe the effect of oral vancomycin treatment in three patients with UC and PSC refractory to conventional and biologic therapies. All three patients achieved clinical remission and mucosal healing with vancomycin 500 mg twice a day administered orally. Maintenance treatment with oral vancomycin was well tolerated and led to sustained clinical and endoscopic remission in all three patients. Oral vancomycin also improved liver function tests in two patients who did not have pre-existing cirrhosis.

Pharmacokinetic and Pharmacodynamic Properties of Rosmarinic Acid in Rat Cholestatic Liver Injury

The objective of this study was to evaluate the hepatoprotective and metabolic effects of rosmarinic acid (RA) in rats. RA [100 mg/kg body weight (BW)] was intragastrically (i.g.) administered to Sprague-Dawley (SD) rats once a day for seven consecutive days. The rats were then i.g. administered α-naphthylisothiocyanate (ANIT) (80 mg/kg once on the 5th day) to induce acute intrahepatic cholestasis after the last administration of RA. Blood samples were collected at different time points (0.083 h, 0.17 h, 0.33 h, 0.5 h, 0.75 h, 1 h, 1.5 h, 3 h, 4 h, 6 h, 8 h, 12 h, 20 h) after administration, and the levels of RA were estimated by HPLC. Plasma and bile biochemical analysis, bile flow rate, and liver histopathology were measured to evaluate the hepatoprotective effect of RA. The PK-PD curves showed obviously clockwise (AST and ALT) or anticlockwise (TBA, TBIL). Pretreatment with RA at different doses significantly restrained ANIT-induced pathological changes in bile rate, TBA, TBIL, ALT, AST (p < 0.05 or p < 0.01). The relationship between RA concentration and its hepatoprotective effects on acute cholestasis responses was assessed by PK-PD modeling.

Endoscopic management of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a rare but clinically important cholestatic liver disease. Histopathologically and cholangiographically, PSC is characterized by intra- and/or extra-hepatic bile duct inflammation and fibro-obliteration, which ultimately leads to biliary cirrhosis and related sequelae, including development of hepatobiliary and colorectal carcinomata. PSC can be diagnosed at essentially any age and carries a median survival of 15-20 years, regardless of age at diagnosis, and is a foremost risk factor for cholangiocarcinoma. Given the chronic and progressive nature of PSC, its inherent association with both neoplastic and non-neoplastic biliary tract complications, and the lack of effective pharmacotherapies, alimentary and biliary tract endoscopy plays a major role in the care of patients with PSC. Areas covered: Here, we provide a narrative review on endoscopic management of PSC, including established and evolving applications to the diagnosis and treatment of both its benign and malignant complications. Expert commentary: Due to the rarity of PSC and the considerable patient-years required to rigorously study major endpoints, there remains a paucity of high-quality evidence regarding its management. As the advanced endoscopic repertoire expands, so has the interest in developing best practices in PSC, which we discuss herein.

Alterations in Intestinal Microbiota Lead to Production of Interleukin 17 by Intrahepatic γδ T-Cell Receptor-Positive Cells and Pathogenesis of Cholestatic Liver Disease

BACKGROUND & AIMS

Variants at the ABCB4 or MDR2 locus, which encodes a biliary transport protein, are associated with a spectrum of cholestatic liver diseases. Exacerbation of liver disease has been linked to increased hepatic levels of interleukin (IL) 17, yet the mechanisms of this increase are not understood. We studied mice with disruption of Mdr2 to determine how defects in liver and alteration in the microbiota contribute to production of IL17 by intrahepatic γδ T cells.

METHODS

We performed studies with Mdr2-/- and littermate FVB/NJ (control) mice. IL17 was measured in serum samples by an enzyme-linked immunosorbent assay. Mice were injected with neutralizing antibodies against the γδ T-cell receptor (TCR; anti-γδ TCR) or mouse IL17A (anti-IL17A). Livers were collected and bacteria were identified in homogenates by culture procedures; TCRγδ+ cells were isolated by flow cytometry. Fecal samples were collected from mice and analyzed by 16S ribosomal DNA sequencing. Cells were stimulated with antibodies or bacteria, and cytokine production was measured. We obtained tissues from 10 patients undergoing liver transplantation for primary sclerosing cholangitis or chronic hepatitis C virus infection. Tissues were analyzed for cytokine production by γδ TCR+ cells.

RESULTS

Mdr2-/- mice had collagen deposition around hepatic bile ducts and periportal-bridging fibrosis with influx of inflammatory cells and increased serum levels of IL17 compared with control mice. Administration of anti-IL17A reduced hepatic fibrosis. Livers from Mdr2-/- mice had increased numbers of IL17A+ γδTCR+ cells-particularly of IL17A+ Vγ6Jγ1 γδ TCR+ cells. Fecal samples from Mdr2-/- mice were enriched in Lactobacillus, and liver tissues were enriched in Lactobacillus gasseri compared with control mice. Mdr2-/- mice also had increased intestinal permeability. The γδ TCR+ cells isolated from Mdr2-/- livers produced IL17 in response to heat-killed L gasseri. Intraperitoneal injection of control mice with L gasseri led to increased serum levels of IL17 and liver infiltration by inflammatory cells; injection of these mice with anti-γδ TCR reduced serum level of IL17. Intravenous injections of Mdr2-/- mice with anti-γδ TCR reduced fibrosis; liver levels of IL17, and inflammatory cells; and serum levels of IL17. γδTCR+ cells isolated from livers of patients with primary sclerosing cholangitis, but not hepatitis C virus infection, produced IL17.

CONCLUSIONS

In Mdr2-/- mice, we found development of liver fibrosis and inflammation to require hepatic activation of γδ TCR+ cells and production of IL17 mediated by exposure to L gasseri. This pathway appears to contribute to development of cholestatic liver disease in patients.

Complications, symptoms, quality of life and pregnancy in cholestatic liver disease

Cholestatic liver diseases (CLDs) encompass a variety of disorders of bile formation and/or flow which generally result in progressive hepatobiliary injury and ultimately end-stage liver disease. Many patients with CLD are diagnosed between the ages of 20-50 years, a particularly productive period of life professionally, biologically and in other respects; it is not surprising, thus, that CLD is often associated with impaired health-related quality of life (HRQOL) and uncertainty regarding implications for and outcomes of pregnancy. Primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC) are the most prominent CLDs, both having considerable morbidity and mortality and representing major indications for liver transplantation. These disorders, as a consequence of their complications (eg ascites, hepatic osteodystrophy), associated conditions (eg inflammatory bowel disease) and symptoms (eg pruritus and fatigue), can significantly impair an array of domains of HRQOL. Here we review these impactful clinical aspects of PSC and PBC as well as the topics of fertility and pregnancy.

Twenty-Year Comparative Analysis of Patients With Autoimmune Liver Diseases on Transplant Waitlists

BACKGROUND & AIMS

The rarity of autoimmune liver disease poses challenges to epidemiology studies. However, waitlists for liver transplantation can be used to study patients with end-stage liver diseases. We used these waitlists to assess trends in numbers and demographics of patients awaiting liver transplant for primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), or autoimmune hepatitis (AIH).

METHODS

We collected data from UK and US national registries for all adults on liver transplant waitlists, from January 1, 1995, through December 31, 2014. We analyzed data from patients with PBC (n = 1434 in the United Kingdom and n = 5598 in the United States), PSC (n = 1093 in the United Kingdom and n = 6820 in the United States), and AIH (n = 538 in the United Kingdom and n = 4949 in the United States). Numbers of listings per year were adjusted to the estimated populations during each year. Regression analyses were used to examine trends and comparative statistics were used to evaluate differences in individual characteristics among groups.

RESULTS

Over the total study period, listings for PBC were 1.2 and 1.0 per million population per year in the United Kingdom and United States, respectively; for PSC, 0.9 and 1.2 per million population per year; and for AIH, 0.5 and 0.8 per million population per year. Over the period studied, numbers of listings for PBC decreased by 50% in both countries; changes in numbers of listings for PSC and AIH were smaller and not consistent between countries. By 2014, PSC had become the leading indication for liver transplantation among patients with autoimmune liver diseases in both countries. Median patient ages at time of listing were lower than those reported as median age of diagnosis for AIH and PBC. The ratio of women:men with PBC decreased by almost 50% from 1995 through 2014. Men with PSC were placed on the waitlist with higher disease severity scores than women in both countries. Among patients with PBC, those of black race were under-represented on waitlists from both countries. Among patients with PSC, Hispanics were under-represented on waitlists in the United States. Patients of non-white races were placed on waitlists at younger ages for all diseases; age differences in waitlist placement varied by up to 10 years, depending on race, among patients with PBC.

CONCLUSIONS

In an analysis of data collected from UK and US national liver transplant registries over 20 years, we found that PSC has become the leading indication for liver transplantation among patients with autoimmune liver diseases. Numbers of patients with PBC placed on waitlists, and the ratio of women:men with PBC, each decreased by almost 50%, possibly due to increased treatment with ursodeoxycholic acid. Within groups of patients on the transplant waitlist for PBC, PSC, or AIH, we found differences in age, sex, disease severity scores, and ethnicity between diseases and countries that require further study.

Cellular senescence in gastrointestinal diseases: from pathogenesis to therapeutics

Senescence is a durable cell cycle arrest that can be induced in response to various stress factors, such as telomere erosion, DNA damage or the aberrant activation of oncogenes. In addition to its well-established role as a stress response programme, research has revealed important physiological roles of senescence in nondisease settings, such as embryonic development, wound healing, tissue repair and ageing. Senescent cells secrete various cytokines, chemokines, matrix remodelling proteases and growth factors, a phenotype collectively referred to as the senescence-associated secretory phenotype. These factors evoke immune responses that, depending on the pathophysiological context, can either prevent or even fuel disease and tumorigenesis. Remarkably, even the gut microbiota can influence senescence in various organs. In this Review, we provide an introduction to cellular senescence, addressed particularly to gastroenterologists and hepatologists, and discuss the implications of senescence for the pathogenesis of malignant and nonmalignant gastrointestinal and hepatobiliary diseases. We conclude with an outlook on how modulation of cellular senescence might be used for therapeutic purposes.

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: What the Gastroenterologist and Hepatologist Needs to Know

Primary sclerosing cholangitis (PSC) is a chronic, idiopathic biliary tract disease characterized by segmental strictures. The disease is progressive with no proven treatments and may eventually lead to cirrhosis and end-stage liver disease. Abrupt changes in liver biochemistries, pain, and/or cholangitis may suggest a dominant stricture amenable to endoscopic therapy or the development of cholangiocarcinoma. Patients with PSC are at increased risk of cholangiocarcinoma. There is a strong association with inflammatory bowel disease, and an associated increased risk of colorectal cancer. Colonoscopy every 1 to 2 years is appropriate.

ETS Proto-oncogene 1 Transcriptionally Up-regulates the Cholangiocyte Senescence-associated Protein Cyclin-dependent Kinase Inhibitor 2A

Primary sclerosing cholangitis (PSC) is a chronic, fibroinflammatory cholangiopathy (disease of the bile ducts) of unknown pathogenesis. We reported that cholangiocyte senescence features prominently in PSC and that neuroblastoma RAS viral oncogene homolog (NRAS) is activated in PSC cholangiocytes. Additionally, persistent microbial insult (e.g. LPSs) induces cyclin-dependent kinase inhibitor 2A (CDKN2A/p16INK4a) expression and senescence in cultured cholangiocytes in an NRAS-dependent manner. However, the molecular mechanisms involved in LPS-induced cholangiocyte senescence and NRAS-dependent regulation of CDKN2A remain unclear. Using our in vitro senescence model, we found that LPS-induced CDKN2A expression coincided with a 4.5-fold increase in ETS1 (ETS proto-oncogene 1) mRNA, suggesting that ETS1 is involved in regulating CDKN2A This idea was confirmed by RNAi-mediated suppression or genetic deletion of ETS1, which blocked CDKN2A expression and reduced cholangiocyte senescence. Furthermore, site-directed mutagenesis of a predicted ETS-binding site within the CDKN2A promoter abolished luciferase reporter activity. Pharmacological inhibition of RAS/MAPK reduced ETS1 and CDKN2A protein expression and CDKN2A promoter-driven luciferase activity by ∼50%. In contrast, constitutively active NRAS expression induced ETS1 and CDKN2A protein expression, whereas ETS1 RNAi blocked this increase. Chromatin immunoprecipitation-PCR detected increased ETS1 and histone 3 lysine 4 trimethylation (H3K4Me3) at the CDKN2A promoter following LPS-induced senescence. Additionally, phospho-ETS1 expression was increased in cholangiocytes of human PSC livers and in the Abcb4 (Mdr2)-/- mouse model of PSC. These data pinpoint ETS1 and H3K4Me3 as key transcriptional regulators in NRAS-induced expression of CDKN2A, and this regulatory axis may therefore represent a potential therapeutic target for PSC treatment.

Prospective Clinical Trial of Rifaximin Therapy for Patients With Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is a rare, chronic, cholestatic liver disease in which emerging data suggest that oral antibiotics may offer therapeutic effects. We enrolled patients with PSC in a 12-week, open-label pilot study to investigate the efficacy and safety of 550 mg of oral rifaximin twice daily. The primary end point was serum alkaline phosphatase (ALK) at 12 weeks. Secondary end points included (1) serum bilirubin, gamma-glutamyl transpeptidase, and Mayo PSC risk score; (2) fatigue impact scale, chronic liver disease questionnaire, and short form health survey (SF-36) scores; and (3) adverse effects (AEs). Analyses were performed with nonparametric tests. Sixteen patients were enrolled, among whom the median age was 40 years; 13 (81%) were male, 13 had inflammatory bowel disease, and baseline ALK was 342 IU/mL (interquartile range, 275-520 IU/mL). After 12 weeks of treatment, there were no significant changes in ALK (median increase of 0.9% to 345 IU/mL; P = 0.47) or any of the secondary biochemical end points (all P > 0.05). Similarly, there were no significant changes in fatigue impact scale, chronic liver disease questionnaire, or SF-36 scores (all P > 0.05). Three patients withdrew from the study due to AEs; 4 others reported mild AEs but completed the study. In conclusion, although some antibiotics may have promise in treating PSC, oral rifaximin, based on the results herein, seems inefficacious for this indication. Future studies are needed to understand how the antimicrobial spectra and other properties of antibiotics might determine their utility in treating PSC.

Long-Term Ursodeoxycholic Acid Therapy Does Not Alter Lithocholic Acid Levels in Patients with Cystic Fibrosis with Associated Liver Disease

OBJECTIVE

To evaluate the fasting and postprandial serum bile acid composition in patients with cystic fibrosis-associated liver disease (CFLD) after chronic administration of ursodeoxycholic acid (UDCA) (20 mg/kg/day). The aim was to specifically focus on the extent of biotransformation of UDCA to its hepatotoxic metabolite, lithocholic acid, because of recent concerns regarding the safety of long-term, high-dose UDCA treatment for CFLD.

STUDY DESIGN

Twenty patients with CFLD (median age 16 years, range: 2.4-35.0) prescribed UDCA therapy for at least 2 years were studied. Total and individual serum bile acids were measured by stable-isotope dilution mass spectrometry, in fasting and 2-hour postprandial samples taken during chronic UDCA (20 mg/kg/day) administration.

RESULTS

During chronic UDCA administration (median duration 8 years, IQR: 6-16), UDCA became the predominant serum bile acid in all patients (median, IQR: 3.17, 1.25-5.56 μmol/L) and chenodeoxycholic acid concentrations were greater than cholic acid (1.86, 1.00-4.70 μmol/L vs 0.40, 0.24-2.71 μmol/L). The secondary bile acids, deoxycholate and lithocholate, were present in very low concentrations in fasted serum (<0.05 μmol/L). After UDCA administration, 2-hour postprandial concentrations of both UDCA and chenodeoxycholic acid significantly increased (P < .01), but no significant changes in serum lithocholic acid concentrations were observed.

CONCLUSION

These data do not support recent suggestions that enhanced biotransformation of UDCA to the hepatotoxic secondary bile acid lithocholic occurs when patients with CFLD are treated with relatively high doses of UDCA.

Evaluation of Biliary Calprotectin as a Biomarker in Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is a chronic inflammatory disease of the bile ducts with limited therapeutic options except liver transplantation. Reliable biomarkers to predict the disease course are unavailable, and currently employed disease activity scores such as the Mayo risk score (MRS) have limitations. The present study aims to evaluate biliary calprotectin as a marker of disease activity and prognosis in PSC.This is a monocentric retrospective observational study. Calprotectin concentrations were measured by an enzyme-linked immunosorbent assay in bile samples collected by endoscopic retrograde cholangiography from 106 PSC patients and 20 controls. Biliary calprotectin concentrations were compared between the 2 groups. In PSC patients, results were evaluated with regard to the presence of dominant bile duct stenoses, bile microbiology, MRS, survival free of liver transplantation, and necessity for bile duct interventions in the further disease course.Median (interquartile ranges) biliary calprotectin concentrations were higher in PSC patients than in controls (3646 ng/mL, 249-9748 vs 116 ng/mL, 104-655; P < 0.001). In the PSC cohort, higher biliary calprotectin concentrations were associated with the presence of microbes in bile (P = 0.02), the occurrence of dominant bile duct stenosis at any time in the disease course (P = 0.005), and the necessity for future bile duct interventions (P = 0.02). Patients with biliary calprotectin concentrations above a cut-off of 11,610 ng/mL displayed significantly shorter transplantation-free survival than those with biliary calprotectin concentrations ≤11,610 ng/mL (P < 0.001). Univariate Cox regression analysis revealed high biliary calprotectin concentration (>11,610 ng/mL) as a risk factor of shorter transplantation-free survival of PSC patients (P < 0.001) beside high plasma alkaline phosphatase (ALP) concentration (>142.5 U/L) (P = 0.006), high MRS (≥2) (P < 0.001), and nonsterility of bile (P = 0.03). Multivariate analysis identified only MRS (P = 0.002) and ALP concentration (P = 0.04) as independent risk factors.Our data strongly suggest that biliary calprotectin may be a valuable additional marker for disease activity and a predictor of outcome in PSC, so that further studies for evaluation of calprotectin in this disease are warranted.

Absence of the intestinal microbiota exacerbates hepatobiliary disease in a murine model of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic, idiopathic, fibroinflammatory cholangiopathy. The role of the microbiota in PSC etiopathogenesis may be fundamentally important, yet remains obscure. We tested the hypothesis that germ-free (GF) mutltidrug resistance 2 knockout (mdr2(-/-) ) mice develop a distinct PSC phenotype, compared to conventionally housed (CV) mdr2(-/-) mice. Mdr2(-/-) mice (n = 12) were rederived as GF by embryo transfer, maintained in isolators, and sacrificed at 60 days in parallel with age-matched CV mdr2(-/-) mice. Serum biochemistries, gallbladder bile acids, and liver sections were examined. Histological findings were validated morphometrically, biochemically, and by immunofluorescence microscopy (IFM). Cholangiocyte senescence was assessed by p16(INK4a) in situ hybridization in liver tissue and by senescence-associated β-galactosidase staining in a culture-based model of insult-induced senescence. Serum biochemistries, including alkaline phosphatase, aspartate aminotransferase, and bilirubin, were significantly higher in GF mdr2(-/-) (P < 0.01). Primary bile acids were similar, whereas secondary bile acids were absent, in GF mdr2(-/-) mice. Fibrosis, ductular reaction, and ductopenia were significantly more severe histopathologically in GF mdr2(-/-) mice (P < 0.01) and were confirmed by hepatic morphometry, hydroxyproline assay, and IFM. Cholangiocyte senescence was significantly increased in GF mdr2(-/-) mice and abrogated in vitro by ursodeoxycholic acid (UDCA) treatment.

CONCLUSIONS

GF mdr2(-/-) mice exhibit exacerbated biochemical and histological features of PSC and increased cholangiocyte senescence, a characteristic and potential mediator of progressive biliary disease. UDCA, a commensal microbial metabolite, abrogates senescence in vitro. These findings demonstrate the importance of the commensal microbiota and its metabolites in protecting against biliary injury and suggest avenues for future studies of biomarkers and therapeutic interventions in PSC.

Brazilian society of hepatology recommendations for the diagnosis and management of autoimmune diseases of the liver

ABSTRACT In order to draw evidence-based recommendations concerning the management of autoimmune diseases of the liver, the Brazilian Society of Hepatology has sponsored a single-topic meeting in October 18th, 2014 at São Paulo. An organizing committee comprised of seven investigators was previously elected by the Governing Board to organize the scientific agenda as well as to select twenty panelists to make a systematic review of the literature and to present topics related to the diagnosis and treatment of autoimmune hepatitis, primary sclerosing cholangitis, primary biliary cirrhosis and their overlap syndromes. After the meeting, all panelists gathered together for the discussion of the topics and the elaboration of those recommendations. The text was subsequently submitted for suggestions and approval of all members of the Brazilian Society of Hepatology through its homepage. The present paper is the final version of the reviewed manuscript organized in topics, followed by the recommendations of the Brazilian Society of Hepatology.

Impaired Itching Perception in Murine Models of Cholestasis Is Supported by Dysregulation of GPBAR1 Signaling

Background & Aims

In cholestatic syndromes, body accumulation of bile acids is thought to cause itching. However, the mechanisms supporting this effect remain elusive. Recently, GPBAR1 (TGR5) a G-protein coupled receptor has been shown to mediate itching caused by intradermal administration of DCA and LCA. 6α-ethyl-3α, 7α-dihydroxy-24-nor-5β-cholan-23-ol (BAR502) is a non-bile acid dual ligand for FXR and GPBAR1.

Methods

Cholestasis was induced in wild type and GPBAR1^-/- mice by administration of α-naphthyl-isothiocyanate (ANIT) or 17α-ethynylestradiol.

Results.

In naïve mice skin application of DCA, TLCA, 6-ECDCA, oleanolic and betulinic acid induces a GPBAR1 dependent pruritogenic response that could be desensitized by re-challenging the mice with the same GPBAR1 agonist. In wild type and GPBAR1^-/- mice cholestasis induced by ANIT fails to induce spontaneous itching and abrogates scratching behavior caused by intradermal administration of DCA. In this model, co-treatment with BAR502 increases survival, attenuates serum alkaline phosphatase levels and robustly modulates the liver expression of canonical FXR target genes including OSTα, BSEP, SHP and MDR1, without inducing pruritus. Betulinic acid, a selective GPBAR1 ligand, failed to rescue wild type and GPBAR1^-/- mice from ANIT cholestasis but did not induced itching. In the 17α-ethynylestradiol model BAR502 attenuates cholestasis and reshapes bile acid pool without inducing itching.

Conclusions

The itching response to intradermal injection of GPBAR1 agonists desensitizes rapidly and is deactivated in models of cholestasis, explain the lack of correlation between bile acids levels and itching severity in cholestatic syndromes. In models of non-obstructive cholestasis, BAR502 attenuates liver injury without causing itching.

Lipopolysaccharide (LPS)-Induced Biliary Epithelial Cell NRas Activation Requires Epidermal Growth Factor Receptor (EGFR)

Cholangiocytes (biliary epithelial cells) actively participate in microbe-induced proinflammatory responses in the liver and contribute to inflammatory and infectious cholangiopathies. We previously demonstrated that cholangiocyte TLR-dependent NRas activation contributes to proinflammatory/ proliferative responses. We test the hypothesis that LPS-induced activation of NRas requires the EGFR. SV40-transformed human cholangiocytes (H69 cells), or low passage normal human cholangiocytes (NHC), were treated with LPS in the presence or absence of EGFR or ADAM metallopeptidase domain 17 (TACE) inhibitors. Ras activation assays, quantitative RT-PCR, and proliferation assays were performed in cells cultured with or without inhibitors or an siRNA to Grb2. Immunofluorescence for phospho-EGFR was performed on LPS-treated mouse samples and specimens from patients with primary sclerosing cholangitis, primary biliary cirrhosis, hepatitis C, and normal livers. LPS-treatment induced an association between the TLR/MyD88 and EGFR/Grb2 signaling apparatus, NRas activation, and EGFR phosphorylation. NRas activation was sensitive to EGFR and TACE inhibitors and correlated with EGFR phosphorylation. The TACE inhibitor and Grb2 depletion prevented LPS-induced IL6 expression (p<0.05) and proliferation (p<0.01). Additionally, cholangiocytes from LPS-treated mouse livers and human primary sclerosing cholangitis (PSC) livers exhibited increased phospho-EGFR (p<0.01). Moreover, LPS-induced mouse cholangiocyte proliferation was inhibited by concurrent treatment with the EGFR inhibitor, Erlotinib. Our results suggest that EGFR is essential for LPS-induced, TLR4/MyD88-mediated NRas activation and induction of a robust proinflammatory cholangiocyte response. These findings have implications not only for revealing the signaling potential of TLRs, but also implicate EGFR as an integral component of cholangiocyte TLR-induced proinflammatory processes.

Calprotectin in bile: a disease severity marker in patients with primary sclerosing cholangitis

GOALS

Our aim was to evaluate the diagnostic potential of calprotectin in serum and bile of patients with primary sclerosing cholangitis (PSC).

BACKGROUND

PSC is a chronic cholestatic liver disease of unknown etiology. It is characterized by progressive inflammation and fibrosis of the bile ducts leading to biliary cirrhosis and eventually liver failure. Reliable markers for disease activity and severity are still lacking. Subunits of calprotectin, a fecal marker of inflammation in inflammatory bowel disease, have been recently identified in bile.

STUDY

Calprotectin was measured in patients with PSC (n=56), cholangiocarcinoma (CC) complicating PSC (CC/PSC) (n=13), CC (n=30), and bile duct stones in bile (n=38) and serum (n=73) by enzyme-linked immunosorbent assay in a cross-sectional study. PSC patients were categorized by the Mayo risk score (MRS) to characterize the disease severity.

RESULTS

Calprotectin is present in bile, and the median concentration was significantly higher in PSC patients (P<0.05). Stratification of PSC patients by MRS showed significantly elevated calprotectin levels in bile in the MRS-high group (P<0.05). Calprotectin and MRS correlated significantly (P<0.05). The presence or absence of inflammatory bowel disease in PSC patients did not alter calprotectin levels in bile. Serum AP and calprotectin in bile correlated significantly (P=0.013). No significant correlation was found for other liver-related parameters. In contrast, serum calprotectin levels were significantly higher in patients with CC, but there was no association with PSC or disease activity/severity.

CONCLUSIONS

Calprotectin in bile is a promising disease marker in patients with PSC with a potential prognostic value.

Characterization of cultured cholangiocytes isolated from livers of patients with primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic, idiopathic cholangiopathy. The role of cholangiocytes (biliary epithelial cells) in PSC pathogenesis is unknown and remains an active area of research. Here, through cellular, molecular and next-generation sequencing (NGS) methods, we characterize and identify phenotypic and signaling features of isolated PSC patient-derived cholangiocytes. We isolated cholangiocytes from stage 4 PSC patient liver explants by dissection, differential filtration and immune-magnetic bead separation. We maintained cholangiocytes in culture and assessed for: (i) cholangiocyte, cell adhesion and inflammatory markers; (ii) proliferation rate; (iii) transepithelial electrical resistance (TEER); (iv) cellular senescence; and (v) transcriptomic profiles by NGS. We used two well-established normal human cholangiocyte cell lines (H69 and NHC) as controls. Isolated PSC cells expressed cholangiocyte (eg, cytokeratin 7 and 19) and epithelial cell adhesion markers (EPCAM, ICAM) and were negative for hepatocyte and myofibroblast markers (albumin, α-actin). Proliferation rate was lower for PSC compared with normal cholangiocytes (4 vs 2 days, respectively, P<0.01). Maximum TEER was also lower in PSC compared with normal cholangiocytes (100 vs 145 Ωcm(2), P<0.05). Interleukin-6 (IL-6) and IL-8 (protein and mRNA) were both increased compared with NHCs and H69s (all P<0.01). The proportion of cholangiocytes staining positive for senescence-associated β-galactosidase was higher in PSC cholangiocytes compared with NHCs (48% vs 5%, P<0.01). Finally, NGS confirmed cholangiocyte marker expression in isolated PSC cholangiocytes and extended our findings regarding pro-inflammatory and senescence-associated signaling. In conclusion, we have demonstrated that high-purity cholangiocytes can be isolated from human PSC liver and grown in primary culture. Isolated PSC cholangiocytes exhibit a phenotype that may reflect their in vivo contribution to disease and serve as a vital tool for in vitro investigation of biliary pathobiology and identification of new therapeutic targets in PSC.

Primary sclerosing cholangitis and the microbiota: current knowledge and perspectives on etiopathogenesis and emerging therapies

Primary sclerosing cholangitis (PSC) is a chronic, fibroinflammatory, cholestatic liver disease of unknown etiopathogenesis. PSC generally progresses to liver cirrhosis, is a major risk factor for hepatobiliary and colonic neoplasia, and confers a median survival to death or liver transplantation of only 12 years. Although it is well recognized that approximately 75% of patients with PSC also have inflammatory bowel disease (IBD), the significance of this association remains elusive. Accumulating evidence now suggests a potentially important role for the intestinal microbiota, and enterohepatic circulation of molecules derived therefrom, as a putative mechanistic link between PSC and IBD and a central pathobiological driver of PSC. In this concise review, we provide a summary of and perspectives regarding the relevant basic, translational, and clinical data, which, taken together, encourage further investigation of the role of the microbiota and microbial metabolites in the etiopathogenesis of PSC and as a potential target for novel pharmacotherapies.

Cholangiocyte senescence by way of N-ras activation is a characteristic of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is an incurable cholangiopathy of unknown etiopathogenesis. Here we tested the hypothesis that cholangiocyte senescence is a pathophysiologically important phenotype in PSC. We assessed markers of cellular senescence and senescence-associated secretory phenotype (SASP) in livers of patients with PSC, primary biliary cirrhosis, hepatitis C, and in normals by fluorescent in situ hybridization (FISH) and immunofluorescence microscopy (IFM). We tested whether endogenous and exogenous biliary constituents affect senescence and SASP in cultured human cholangiocytes. We determined in coculture whether senescent cholangiocytes induce senescence in bystander cholangiocytes. Finally, we explored signaling mechanisms involved in cholangiocyte senescence and SASP. In vivo, PSC cholangiocytes expressed significantly more senescence-associated p16(INK4a) and γH2A.x compared to the other three conditions; expression of profibroinflammatory SASP components (i.e., IL-6, IL-8, CCL2, PAI-1) was also highest in PSC cholangiocytes. In vitro, several biologically relevant endogenous (e.g., cholestane 3,5,6 oxysterol) and exogenous (e.g., lipopolysaccharide) molecules normally present in bile induced cholangiocyte senescence and SASP. Furthermore, experimentally induced senescent human cholangiocytes caused senescence in bystander cholangiocytes. N-Ras, a known inducer of senescence, was increased in PSC cholangiocytes and in experimentally induced senescent cultured cholangiocytes; inhibition of Ras abrogated experimentally induced senescence and SASP.

CONCLUSION

Cholangiocyte senescence induced by biliary constituents by way of N-Ras activation is an important pathogenic mechanism in PSC. Pharmacologic inhibition of N-Ras with a resultant reduction in cholangiocyte senescence and SASP is a new therapeutic approach for PSC.

Role of the microbiota and antibiotics in primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is an idiopathic, progressive, cholestatic liver disease with considerable morbidity and mortality and no established pharmacotherapy. In addition to the long-recognized association between PSC and inflammatory bowel disease, several lines of preclinical and clinical evidence implicate the microbiota in the etiopathogenesis of PSC. Here we provide a concise review of these data which, taken together, support further investigation of the role of the microbiota and antibiotics in PSC as potential avenues toward elucidating safe and effective pharmacotherapy for patients afflicted by this illness.

Micro-computed tomography and nuclear magnetic resonance imaging for noninvasive, live-mouse cholangiography

The cholangiopathies are a diverse group of biliary tract disorders, many of which lack effective treatment. Murine models are an important tool for studying their pathogenesis, but existing noninvasive methods for assessing biliary disease in vivo are not optimal. Here we report our experience with using micro-computed tomography (microCT) and nuclear magnetic resonance (MR) imaging to develop a technique for live-mouse cholangiography. Using mdr2 knockout (mdr2KO, a model for primary sclerosing cholangitis (PSC)), bile duct-ligated (BDL), and normal mice, we performed in vivo: (1) microCT on a Siemens Inveon PET/CT scanner and (2) MR on a Bruker Avance 16.4 T spectrometer, using Turbo Rapid Acquisition with Relaxation Enhancement, IntraGate Fast Low Angle Shot, and Half-Fourier Acquisition Single-shot Turbo Spin Echo methods. Anesthesia was with 1.5-2.5% isoflurane. Scans were performed with and without contrast agents (iodipamide meglumine (microCT), gadoxetate disodium (MR)). Dissection and liver histology were performed for validation. With microCT, only the gallbladder and extrahepatic bile ducts were visualized despite attempts to optimize timing, route, and dose of contrast. With MR, the gallbladder, extra-, and intrahepatic bile ducts were well-visualized in mdr2KO mice; the cholangiographic appearance was similar to that of PSC (eg, multifocal strictures) and could be improved with contrast administration. In BDL mice, MR revealed cholangiographically distinct progressive dilation of the biliary tree without ductal irregularity. In normal mice, MR allowed visualization of the gallbladder and extrahepatic ducts, but only marginal visualization of the diminutive intrahepatic ducts. One mouse died during microCT and MR imaging, respectively. Both microCT and MR scans could be obtained in ≤20 min. We, therefore, demonstrate that MR cholangiography can be a useful tool for longitudinal studies of the biliary tree in live mice, whereas microCT yields suboptimal duct visualization despite requiring contrast administration. These findings support further development and application of MR cholangiography to the study of mouse models of PSC and other cholangiopathies.

Randomised clinical trial: vancomycin or metronidazole in patients with primary sclerosing cholangitis - a pilot study

BACKGROUND

Emerging data suggest that oral antibiotics may have therapeutic effects in primary sclerosing cholangitis (PSC), but published studies are limited.

AIMS

To investigate the safety and efficacy of oral vancomycin and metronidazole in patients with PSC.

METHODS

Thirty-five patients with PSC were randomised in a double-blind manner into four groups: vancomycin 125 mg or 250 mg four times/day, or metronidazole 250 mg or 500 mg three times/day for 12 weeks. The primary endpoint was decrease in alkaline phosphatase (ALK) at 12 weeks. Secondary end points included serum bilirubin and Mayo PSC risk score; pruritus; and adverse effects (AEs). Nonparametric tests were used for analysis.

RESULTS

The primary endpoint was reached in the low-dose (-43% change in ALK, P = 0.03) and high-dose (-40%, P = 0.02) vancomycin groups, with two patients in the former experiencing ALK normalisation. Bilirubin decreased significantly in the low-dose metronidazole group (-20%, P = 0.03) and trended towards significance in the low-dose vancomycin group (-33%, P = 0.06). Mayo PSC risk score decreased significantly in the low-dose vancomycin (-0.55, P = 0.02) and low-dose metronidazole group (-0.16, P = 0.03). Pruritus decreased significantly in the high-dose metronidazole group (-3.4, P = 0.03). AEs led to medication discontinuation in six patients, four of whom were receiving metronidazole.

CONCLUSIONS

Both vancomycin and metronidazole demonstrated efficacy; however, only patients in the vancomycin groups reached the primary endpoint, and with less adverse effects. Larger, longer-term studies are needed to further examine the safety and efficacy of antibiotics as a potential treatment for patients with primary sclerosing cholangitis (clinicaltrials.gov NCT01085760).

Challenges of Cholangiocarcinoma Detection in Patients with Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is a chronic, cholestatic, idiopathic liver disease characterized by fibro-obliterative inflammation of the hepatic bile ducts. In a clinically significant proportion of patients, PSC progresses to cirrhosis, end-stage liver disease, and in some cases, cholangiocarcinoma (CCA). The development of CCA in PSC is unpredictable, its surveillance and diagnosis complex, and its treatment options limited unless detected early. Herein we provide a focused review of the current literature regarding CCA surveillance in patients with PSC and discuss the diagnostic and management challenges that exist. Where evidence is limited, we present our perspective and approach as well as directions for future research.