Advances and controversies in the pathogenesis and management of primary sclerosing cholangitis

Alterations in Gut Microbiota Profiles of Mice Infected with Echinococcus granulosus sensu lato Microbiota Profiles of Mice Infected with E. granulosus s.l

OBJECTIVE

Cystic echinococcosis is a kind of parasitic disease that seriously endangers human and animal health. At present, its prevention and treatment still do not achieve the desired results. The aims of this study were to explore the effect of CE on intestinal microflora in mice.

METHODS

In this study, 16S rRNA metagenome sequencing and bioinformatics were used to analyze the intestinal flora of mice infected with E. granulosus s.l. Changes in intestinal microbial community abundance were investigated and the differences in microbial populations of mice infected with E. granulosus s.l. were screened.

RESULTS

Our results show that at the phylum level, nine abundant taxa were identified, the relative abundance of Firmicutes and Proteobacteria were enriched in infected mice, whereas Bacteroidetes and Patescibacteria were enriched in control mice (P < 0.01). At the class level, 13 abundant taxa were identified, the relative abundance of Bacilli was enriched in control mice, but decreased in infected mice (P < 0.01). At the order level, 15 abundant taxa were identified, the relative abundance of Lactobacillales was enriched in control mice, but decreased in infected mice (P < 0.01). At the family level, 28 abundant taxa were identified, enriched bacteria in the infected mice was Streptococcaceae, while the enriched bacteria in the control group was Lactobacillaceae (P < 0.01). At the genus level, 79 abundant taxa were identified, enriched bacteria in the infected mice was Streptococcus, while the enriched bacteria in the control group was uncultured_bacterium_f_Eggerthellaceae (P < 0.01). At the species level, 80 abundant taxa were identified, enriched bacteria in the infected mice was uncultured_bacterium_g_Streptococcus, while the enriched bacteria in the control group was uncultured_bacterium_f_Eggerthellaceae (P < 0.01). 39 KEGG pathways were identified that were differentially enriched between the infected and control mice.

CONCLUSION

This study comprehensively demonstrates the differential intestinal microbiota of infected mice and analyzes the metabolic pathways related to the specific microbiota. This could provide new targets and research direction for the treatment and prevention of diseases caused by E. granulosus s.l.

Primary Biliary Cholangitis and Primary Sclerosing Cholangitis: Current Knowledge of Pathogenesis and Therapeutics

Cholangiopathies encompass various biliary diseases affecting the biliary epithelium, resulting in cholestasis, inflammation, fibrosis, and ultimately liver cirrhosis. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are the most important progressive cholangiopathies in adults. Much research has broadened the scope of disease biology to genetic risk, epigenetic changes, dysregulated mucosal immunity, altered biliary epithelial cell function, and dysbiosis, all of which interact and arise in the context of ill-defined environmental triggers. An in-depth understanding of the molecular pathogenesis of these cholestatic diseases will help clinicians better prevent and treat diseases. In this review, we focus on the main underlying mechanisms of disease initiation and progression, and novel targeted therapeutics beyond currently approved treatments.

Circulating Macrophage Activation Markers Predict Transplant-Free Survival in Patients With Primary Sclerosing Cholangitis

INTRODUCTION

Primary sclerosing cholangitis (PSC) is a progressive liver disease characterized by bile duct inflammation and fibrosis. The role of macrophages in PSC development and progression is less studied. Macrophage activation markers soluble (s)CD163 and mannose receptor (sMR) are associated with disease severity and outcome in other liver diseases, but not previously investigated in PSC. We evaluated sCD163 and sMR regarding disease severity and prognosis in patients with PSC.

METHODS

We investigated 2 independent PSC cohorts from Oslo (n = 138) and Helsinki (n = 159) and analyzed blood sCD163 and sMR levels. The Mayo score, Enhanced Liver Fibrosis Test, and Amsterdam-Oxford model were assessed for comparison.

RESULTS

Median (interquartile range) sCD163 was 3.32 (2.27-5.60) and 1.96 (1.47-2.70) mg/L in the Oslo and Helsinki cohorts, respectively, reflecting differences in disease severity between cohorts. Median sMR was similar in both cohorts, 0.28 (0.22-0.44) and 0.28 mg/L (0.20-0.36), respectively. In both cohorts, sCD163 and sMR levels raised with increasing disease severity (liver enzymes, Mayo score, and enhanced liver fibrosis test). Patients with high baseline levels of sCD163 had shorter transplant-free survival than patients with low baseline levels. Furthermore, sCD163 was associated with transplant-free survival in univariate cox-regression analyses. Both sCD163 and sMR performed better in the Oslo cohort of more severely diseased patients than those in the Helsinki cohort of more mildly diseased patients.

DISCUSSION

Macrophage activation markers are elevated according to disease severity suggesting an important role of macrophages in PSC. Furthermore, sCD163 was identified as a prognostic marker and predictor of transplant-free survival in PSC (see Visual Abstract, Supplementary Digital Content 4, http://links.lww.com/CTG/A516).

APOE-ε4 Carrier Status and Gut Microbiota Dysbiosis in Patients With Alzheimer Disease

BACKGROUND

Alternations in gut microbiota and a number of genes have been implicated as risk factors for the development of Alzheimer disease (AD). However, the interactions between the altered bacteria and risk genetic variants remain unclear.

OBJECTIVE

We aimed to explore associations of the risk genetic variants with altered gut bacteria in the onset of AD.

METHODS

We collected baseline data and stool and blood samples from 30 AD patients and 47 healthy controls in a case-control study. The rs42358/rs4512 (ApoE), rs3851179 (PICALM), rs744373 (BIN1), rs9331888 (CLU), rs670139 (MS4A4E), rs3764650 (ABCA7), rs3865444 (CD33), rs9349407 (CD2AP), rs11771145 (EPHA1), and rs3818361/rs6656401 (CR1) were sequenced, and microbiota composition was characterized using 16S rRNA gene sequencing. The associations of the altered gut bacteria with the risk genetics were analyzed.

RESULTS

Apolipoprotein ε4 allele and rs744373 were risk loci for the AD among 12 genetic variants. Phylum Proteobacteria; orders Enterobacteriales, Deltaproteobacteria, and Desulfovibrionales; families Enterobacteriaceae and Desulfovibrionaceae; and genera Escherichia-Shigella, Ruminococcaceae_UCG_002, Shuttleworthia, Anaerofustis, Morganelia, Finegoldia, and Anaerotruncus were increased in AD subjects, whereas family Enterococcaceae and genera Megamonas, Enterococcus, and Anaerostipes were more abundant in controls (P < 0.05). Among the altered microbiota, APOE ε4 allele was positively associated with pathogens: Proteobacteria.

CONCLUSION

The interaction of APOE ε4 gene and the AD-promoting pathogens might be an important factor requiring for the promotion of AD. Targeting to microbiota might be an effective therapeutic strategy for AD susceptible to APOE ε4 allele. This needs further investigation.

Glycomic analysis of antibody indicates distinctive glycosylation profile in patients with autoimmune cholangitis

Glycosylation of antibodies, particularly in the Fc domain, critically modulate the ability of antibodies to bind to FcRs, maintaining immune quiescence to achieve a finely orchestrated immune response. The removal of sialic acid and galactose residues dramatically alters the physiological function of IgGs, and alterations of Ig glycosylation have been associated with several autoimmune disorders. However, Ig glycosylation has not been extensively studied in autoimmune cholangitis. We applied triple quadruple mass spectroscopy with subsequent multiple reaction monitoring to elucidate the profile, composition and linkage of sugar residues of antibody glycans in patients with primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC) and healthy controls (HC). Agalactosylated, HexNAc terminated IgG1 glycoforms were enriched in both PBC and PSC. Levels of IgM glycans at site N439 and fucosylated glycans in J chain, were significantly decreased in PBC compared to PSC and HC. PSC patients had decreased bisecting glycoforms and increased biantennary glycoforms on IgA compared to PBC. Importantly, our data demonstrate the association of distinct branching and composition patterns of Ig glycoforms with disease severity and liver cirrhosis, which highlight the importance of glycan biology as a potential mechanism and/or a disease specific signal of inflammation.

The ectonucleotidase ENTPD1/CD39 limits biliary injury and fibrosis in mouse models of sclerosing cholangitis

The pathogenesis of primary sclerosing cholangitis (PSC) and the mechanistic link to inflammatory bowel disease remain ill‐defined. Ectonucleoside triphosphate diphosphohydrolase‐1 (ENTPD1)/clusters of differentiation (CD) 39, the dominant purinergic ecto‐enzyme, modulates intestinal inflammation. Here, we have explored the role of CD39 in biliary injury and fibrosis. The impact of CD39 deletion on disease severity was studied in multidrug resistance protein 2 (Mdr2)–/– and 3,5‐diethoxycarbonyl‐1,4‐dihydrocollidine mouse models of sclerosing cholangitis and biliary fibrosis. Antibody‐mediated CD8+ T‐cell depletion, selective gut decontamination, experimental colitis, and administration of stable adenosine triphosphate (ATP) agonist were performed. Retinoic acid‐induced gut imprinting on T cells was studied in vitro. Over half of Mdr2–/–;CD39–/– double mutants, expected by Mendelian genetics, died in utero. Compared to Mdr2–/–;CD39+/+, surviving Mdr2–/–;CD39–/– mice demonstrated exacerbated liver injury, fibrosis, and ductular reaction. CD39 deficiency led to a selective increase in hepatic CD8+ T cells and integrin α4β7, a T‐cell gut‐tropism receptor. CD8+ cell depletion in Mdr2–/–;CD39–/– mice diminished hepatobiliary injury and fibrosis. Treatment with antibiotics attenuated, whereas dextran sulfate sodium‐induced colitis exacerbated, liver fibrosis in Mdr2–/– mice. Colonic administration of αβ‐ATP into CD39‐sufficient Mdr2–/– mice triggered hepatic CD8+ cell influx and recapitulated the severe phenotype observed in Mdr2–/–;CD39–/– mice. In vitro, addition of ATP promoted the retinoic acid‐induced imprinting of gut‐homing integrin α4β7 on naive CD8+ cells. CD39 expression was relatively low in human normal or PSC livers but abundantly present on immune cells of the colon and further up‐regulated in samples of patients with inflammatory bowel disease. Conclusion: CD39 deletion promotes biliary injury and fibrosis through gut‐imprinted CD8+ T cells. Pharmacological modulation of purinergic signaling may represent a promising approach for the treatment of PSC. (Hepatology Communications 2017;1:957–972)

Patients with inflammatory bowel disease have increased risk of autoimmune and inflammatory diseases

AIM

To investigate whether immune mediated diseases (IMD) are more frequent in patients with inflammatory bowel disease (IBD).

METHODS

In this population based registry study, a total of 47325 patients with IBD were alive and registered in the Danish National Patient Registry on December 16, 2013. Controls were randomly selected from the Danish Civil Registration System (CRS) and matched for sex, age, and municipality. We used ICD 10 codes to identify the diagnoses of the included patients. The IBD population was divided into three subgroups: Ulcerative colitis (UC), Crohn’s disease (CD) and Both the latter referring to those registered with both diagnoses. Subsequently, odds-ratios (OR) and 95%CI were obtained separately for each group and their respective controls. The use of Bonferoni post-test correction adjusted the significance level to P < 0.00125. P-values were estimated using Fisher’s exact test.

RESULTS

There were significantly more women than men in the registry, and a greater percentage of comorbidity in the IBD groups (P < 0.05). Twenty different IMDs were all significantly more frequent in the IBD group. Sixteen were associated with UC versus twelve with CD. In both UC and CD ORs were significantly increased (P < 0.00125) for primary sclerosing cholangitis (PSC), celiac disease, type 1 diabetes (T1D), sarcoidosis, asthma, iridocyclitis, psoriasis, pyoderma gangrenosum, rheumatoid arthritis, and ankylosing spondylitis. Restricted to UC (P < 0.00125) were autoimmune hepatitis, primary biliary cholangitis, Grave’s disease, polymyalgia rheumatica, temporal arteritis , and atrophic gastritis. Restricted to CD (P < 0.00125) were psoriatic arthritis and episcleritis. Restricted to women with UC (P < 0.00125) were atrophic gastritis, rheumatoid arthritis, temporal arteritis, and polymyalgia rheumatica. Restricted to women with CD were episcleritis, rheumatoid arthritis, and psoriatic arthritis. The only disease restricted to men (P < 0.00125) was sarcoidosis.

CONCLUSION

Immune mediated diseases were significantly more frequent in patients with IBD. Our results strengthen the hypothesis that some IMDs and IBD may have overlapping pathogenic pathways.

Bile microbiota in primary sclerosing cholangitis: Impact on disease progression and development of biliary dysplasia

Objective

The etiopathogenesis and risk for development of biliary neoplasia in primary sclerosing cholangitis (PSC) are largely unknown. Microbes or their metabolites have been suggested to play a role. To explore this potential microbial involvement, we evaluated the differences in biliary microbiota in PSC patients at an early disease stage without previous endoscopic retrograde cholangiography (ERC) examinations, advanced disease stage, and with biliary dysplasia or cholangiocarcinoma.

Design

Bile samples from the common bile duct were collected from 46 controls and 80 patients with PSC during ERC (37 with early disease, 32 with advanced disease, and 11 with biliary dysplasia). DNA isolation, amplification, and Illumina MiSeq sequencing were performed for the V1-V3 regions of the bacterial 16S rRNA gene.

Results

The most common phyla found were Bacteroidetes, Firmicutes, Proteobacteria, Fusobacteria, and Actinobacteria. The most common families were Prevotellaceae, Streptococcaceae, Veillonellaceae, Fusobacteriaceae, and Pasteurellaceae, and the most common genera were Prevotella, Streptococcus, Veillonella, Fusobacterium, and Haemophilus. The bacterial communities of non-PSC subjects and early stage PSC patients were similar. Alpha diversity was lower in patients with biliary dysplasia/cholangiocarcinoma than in other groups. An increase in Streptococcus abundance was positively correlated with the number of ERC examinations. Streptococcus abundance was also positively correlated with an increase in disease severity, even after controlling for the number of ERC examinations.

Conclusions

Our findings suggest that the aetiology of PSC is not associated with changes in bile microbial communities, but the genus Streptococcus may play a pathogenic role in the progression of the disease.

Pathogenesis and clinical spectrum of primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a disease of the biliary tract, which has been documented in the literature since 1867. This disease has a strong predilection for affecting men and can be seen in individuals as young as 2 years of age. PSC has a strong associated with inflammatory bowel disease, more commonly with ulcerative colitis, and is also part of the clinical spectrum of IgG4-related diseases. Small-duct PSC, a variant of PSC, also has an association with inflammatory bowel disease. The exact pathogenesis of PSC is not well understood at present, however, is likely a combination of a genetic predisposition with alteration of the molecular structure of the gut. Abnormal serum liver chemistry and presence of certain autoimmune markers are usually the first indicators leading to a diagnosis of PCS, however, these may often be normal in early stages of this disease. The diagnosis is made by cholangiography, which is now considered the gold standard. PSC is a known pre-malignant condition. Such patients have an increased risk of developing cholangiocarcinoma, gallbladder neoplasia, and colon cancer. Many new treatment modalities have emerged in the recent past, including anti-tumor necrosis factor- α and anti-integrins; however, liver transplantation is the only known cure for PSC. Despite past and present research, PSC remains an enigmatic biliary disease with few viable treatment options.

Primary Sclerosing Cholangitis: Therapeutic Options and Surveillance Management

Primary sclerosing cholangitis is a chronic immune-mediated liver disease. Though rare, it poses several clinical concerns for the managing physician. There are currently limited therapeutic options in the management of the condition and weak evidence base behind them. Endoscopic intervention is limited to those patients with obstructing stricture-related disease, and even liver transplantation has a risk of disease recurrence. Surveillance for inflammatory bowel disorders, metabolic bone disease, and malignancy is paramount when managing such patients. This article provides an overview of the condition with further focus on current therapeutic options and guidance on surveillance management.

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.

Impact of Concurrent Non-IBD Immunological Diseases on the Outcome of Primary Sclerosing Cholangitis

BACKGROUND

The association between primary sclerosing cholangitis (PSC) and underlying inflammatory bowel disease (IBD) is well established. There are scant data on the association between non-IBD immunological diseases (NID) and PSC outcomes. Our objective was to investigate the impact of NID on the clinical outcomes in patients with PSC.

METHODS

We included 287 patients with PSC from 1985 to 2013 from our tertiary care data registry. Univariate and multivariate analyses were performed to assess the risk factors for liver transplantation.

RESULTS

Of the 287 patients with PSC, 38 (13.2%) patients had at least 1 concomitant immunological disease other than IBD; 241 patients (84.0%) had concurrent IBD. The most frequent NIDs were autoimmune thyroiditis, autoimmune hepatitis, and rheumatoid arthritis. The median follow-up time did not differ significantly between PSC patients with and without NID (10.5 years versus 7.0 years, P = 0.04). We did not find significant difference in the median time from PSC diagnosis to liver transplantation between PSC patients with and without NID (5.2 versus 6.3 years, P = 0.74). In the subgroup analysis, there was no significant difference in the median time from PSC diagnosis to liver transplantation between the PSC-only group, PSC with IBD group, and PSC with NID group (5.4 versus 6.4 versus 5.2 years, P = 0.22).

CONCLUSIONS

The association of NID in patients with PSC did not seem to affect the need for liver transplantation or transplantation-free survival. The findings suggest that the increased load of autoimmunity, including the presence of IBD or NID, has a minimum impact on the disease outcome of PSC.

Selective biologics for ulcerative colitis and Crohn's disease - clinical utility of vedolizumab

Inflammatory bowel disease (IBD) encompasses a cluster of different disease phenotypes which are broadly classified into ulcerative colitis and Crohn’s disease. Disease pathogenesis is driven by abnormal host immune responses to their resident gut microbiome in genetically susceptible individuals. Clinical disease features and outcomes are heterogenous and not unexpected as over 163 genetic loci are associated with disease susceptibility, and there are great variability in environmental exposures. Despite this variability, there has been relatively few efficacious therapies for particularly moderate-to-severe IBD. Treatment has been dominated by antitumor necrosis alpha agents with significant success but equally potentially serious adverse events. Therapeutic targeting of leucocyte trafficking has emerged as a viable alternative therapy, with vedolizumab being the lead compound. This review focuses primarily on its biological function as a selective gut immunotherapy, its safety and efficacy, and its emerging role as a mainstream therapy in managing IBD.

Current Concepts in Primary Biliary Cirrhosis and Primary Sclerosing Cholangitis

Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are chronic, cholestatic diseases of the liver with common clinical manifestations. Early diagnosis and treatment of PBC slows progression and decreases the need for transplant. However, one-third of patients will progress regardless of treatment. Bilirubin <1.0 and alkaline phosphatase <2.0 x the upper limit of normal at 1 year after treatment appear to predict 10-year survival. Ursodeoxycholic acid (UDCA) is the recommended treatment for PBC, and recent studies with obeticholic acid showed promising results for UDCA non-responders. Unlike PBC, no therapy has been shown to alter the natural history of PSC. The recommended initial diagnostic test for PSC is magnetic resonance cholangiopancreatography, typically showing bile duct wall thickening, focal bile duct dilatation, and saccular dilatation of the intra- and/or extrahepatic bile ducts. Immunoglobulin 4-associated cholangitis must be excluded when considering the diagnosis of PSC, to allow for proper treatment, and monitoring of disease progression. In addition to the lack of therapy, PSC is a pre-malignant condition and close surveillance is indicated.

Primary sclerosing cholangitis: a clinical update

INTRODUCTION

Primary sclerosing cholangitis (PSC) is a progressive cholestatic disorder that ultimately can lead to cirrhosis, liver failure, malignancy and death. It is strongly associated with inflammatory bowel disease (IBD), and though a rare disease, its incidence is increasing. There are no proven medical therapies for PSC.

SOURCES OF DATA

Ovid Medline was utilised to search for articles with keywords 'sclerosing cholangitis' and 'cholangiocarcinoma' and containing titles 'primary sclerosing cholangitis', and references of these papers were cross-referenced for further relevant manuscripts.

AREAS OF AGREEMENT

PSC is a rare disease, and there is a strong association with risk loci within the major histocompatibility complex and other genes common to other autoimmune diseases. PSC is a premalignant condition, associated with higher rates of hepatobiliary and colorectal cancer in patients with ulcerative colitis (UC).

AREAS OF CONTROVERSY

The pathogenesis is unclear, and competing theories exist surrounding toxic bile acids, enhanced homing of particular T cells from the gut to the liver and increased passage of toxins to the liver through a permeable bowel wall. It is unclear whether the higher rate of colonic cancer in PSC/UC occurs in PSC/Crohn's disease. Ursodeoxycholic acid therapy reduces liver enzymes but has not been shown to improve survival. It may reduce the prevalence of bowel cancer.

GROWING POINTS

Recent genetic studies have revealed new risk loci, pointing to the importance of the immune system and its interaction with the biome.

AREAS TIMELY FOR DEVELOPING RESEARCH

On the basis of the genetic studies discussed earlier, novel agents are being developed and trialled in the treatment of PSC.