Gut Microbiota Alterations and Circulating Imidazole Propionate Levels Are Associated With Obstructive Coronary Artery Disease in People With HIV.

BACKGROUND: The impact of gut microbiota and its metabolites on coronary artery disease (CAD) in people with human immunodeficiency virus (PWH) is unknown. Emerging evidence suggests that imidazole propionate (ImP), a microbial metabolite, is linked with cardiometabolic diseases. METHODS: Fecal samples from participants of the Copenhagen Comorbidity in HIV infection (COCOMO) study were processed for 16S rRNA sequencing and ImP measured with liquid chromatography-tandem mass spectrometry. CAD severity was investigated by coronary computed tomography-angiography, and participants grouped according to obstructive CAD (n = 60), nonobstructive CAD (n = 80), or no CAD (n = 114). RESULTS: Participants with obstructive CAD had a gut microbiota with lower diversity and distinct compositional shift, with increased abundance of Rumiococcus gnavus and Veillonella, known producers of ImP. ImP plasma levels were associated with this dysbiosis, and significantly elevated in participants with obstructive CAD. However, gut dysbiosis but not plasma ImP was independently associated with obstructive CAD after adjustment for traditional and HIV-related risk factors (adjusted odds ratio, 2.7; 95% confidence interval, 1.1-7.2; P = .048). CONCLUSIONS: PWH with obstructive CAD displays a distinct gut microbiota profile and increased circulating ImP plasma levels. Future studies should determine whether gut dysbiosis and related metabolites such as ImP are predictive of incident cardiovascular events.

Duodenal inflammation in common variable immunodeficiency has altered transcriptional response to viruses.

BACKGROUND: A substantial proportion of common variable immunodeficiency (CVID) patients has duodenal inflammation of largely unknown etiology. However, because of its histologic similarities with celiac disease, gluten sensitivity has been proposed as a potential mechanism. OBJECTIVE: We aimed to elucidate the role of the duodenal microenvironment in the pathogenesis of duodenal inflammation in CVID by investigating the transcriptional, proteomic, and microbial signatures of duodenal biopsy samples in CVID. METHODS: DNA, total RNA, and protein were isolated from snap-frozen pieces of duodenal biopsy samples from CVID (with and without duodenal inflammation), healthy controls, and patients with celiac disease (untreated). RNA sequencing, mass spectrometry-based proteomics, and 16S ribosomal DNA sequencing (bacteria) were then performed. RESULTS: CVID separated from controls in regulation of transcriptional response to lipopolysaccharide and cellular immune responses. These differences were independent of mucosal inflammation. Instead, CVID patients with duodenal inflammation displayed alterations in transcription of genes involved in response to viral infections. Four proteins were differently regulated between CVID patients and healthy controls-DBNL, TRMT11, GCHFR, and IGHA2-independent of duodenal inflammation. Despite similar histology, there were major differences in CVID with duodenal inflammation and celiac disease both at the RNA and protein level. No significant difference was observed in the bacterial gut microbial signature between CVID, celiac, and healthy controls. CONCLUSION: Our findings suggest the existence of altered functions of the duodenal epithelium, particularly in response to lipopolysaccharide and viruses. The latter finding was related to duodenal inflammation, suggesting that viruses, not gluten sensitivity, could be related to duodenal inflammation in CVID.

A shared mucosal gut microbiota signature in primary sclerosing cholangitis before and after liver transplantation.

BACKGROUND AND AIMS: Several characteristic features of the fecal microbiota have been described in primary sclerosing cholangitis (PSC), whereas data on mucosal microbiota are less consistent. We aimed to use a large colonoscopy cohort to investigate key knowledge gaps, including the role of gut microbiota in PSC with inflammatory bowel disease (IBD), the effect of liver transplantation (LT), and whether recurrent PSC (rPSC) may be used to define consistent microbiota features in PSC irrespective of LT. APPROACH AND RESULTS: We included 84 PSC and 51 liver transplanted PSC patients (PSC-LT) and 40 healthy controls (HCs) and performed sequencing of the 16S ribosomal RNA gene (V3-V4) from ileocolonic biopsies. Intraindividual microbial diversity was reduced in both PSC and PSC-LT versus HCs. An expansion of Proteobacteria was more pronounced in PSC-LT (up to 19% relative abundance) than in PSC (up to 11%) and HCs (up to 8%; Q FDR < 0.05). When investigating PSC before (PSC vs. HC) and after LT (rPSC vs. no-rPSC), increased variability (dispersion) in the PSC group was found. Five genera were associated with PSC before and after LT. A dysbiosis index calculated from the five genera, and the presence of the potential pathobiont, Klebsiella , were associated with reduced LT-free survival. Concomitant IBD was associated with reduced Akkermansia . CONCLUSIONS: Consistent mucosal microbiota features associated with PSC, PSC-IBD, and disease severity, irrespective of LT status, highlight the usefulness of investigating PSC and rPSC in parallel, and suggest that the impact of gut microbiota on posttransplant liver health should be investigated further.

Human Immunodeficiency Virus-Infected Immunological Nonresponders Have Colon-Restricted Gut Mucosal Immune Dysfunction.

BACKGROUND: Human immunodeficiency virus (HIV)-infected immunological nonresponders (INRs) fail to reconstitute their CD4+ T-cell pool after initiation of antiretroviral therapy, and their prognosis is inferior to that of immunological responders (IRs). A prevailing hypothesis is that the INR phenotype is caused by a persistently disrupted mucosal barrier, but assessments of gut mucosal immunology in different anatomical compartments are scarce. METHODS: We investigated circulating markers of mucosal dysfunction, immune activation, mucosal Th17 and Th22 cells, and mucosa-adherent microbiota signatures in gut mucosal specimens from sigmoid colon and terminal ileum of 19 INRs and 20 IRs in addition to 20 HIV-negative individuals. RESULTS: INRs had higher blood levels of the enterocyte damage marker intestinal fatty acid-binding protein than IRs. In gut mucosal biopsies, INRs had lower fractions of CD4+ T cells, higher fractions of interleukin 22, and a tendency to higher fractions of interleukin 17-producing CD4+ T cells. These findings were all restricted to the colon and correlated to circulating markers of enterocyte damage. There were no observed differences in gut microbial composition between INRs and IRs. CONCLUSIONS: Restricted to the colon, enterocyte damage and mucosal immune dysfunction play a role for insufficient immune reconstitution in HIV infection independent of the gut microbiota.

Probiotics to HIV-Infected Immunological Nonresponders: Altered Mucosal Immunity and Microbial Diversity Restricted to Ileum.

BACKGROUND: HIV-infected immunological nonresponders (INRs) have increased risk of non-AIDS morbidity and compromised gut barrier immunity. Probiotics are widely used to improve health. We assessed the effects of probiotics in INRs with a comprehensive analysis of gut immunity and microbiome in terminal ileum and sigmoid colon. METHODS: The study involved clinical intervention with five-strain probiotic capsules (1.2 × 1010 CFUs/d) for 8 weeks in 20 INRs with CD4+ T-cell counts <400 cells/µL and plasma HIV RNA <50 copies/mL for more than 3.5 years. Colonoscopy with sampling of gut biopsies from terminal ileum and sigmoid colon and fecal and blood sampling were performed before and after the intervention. Flow cytometry (cytokine production, immune activation, and exhaustion), ELISA (inflammation, microbial translocation, and enterocyte damage), and 16S rRNA sequencing analyses were applied. RESULTS: In the terminal ileum, increased alpha diversity, increased abundance of Bifidobacterium sp., and decreased frequencies of IL-22+ CD4+ T cells were observed. The increased abundance of Bifidobacterium sp. in the terminal ileum correlated with increased fraction of CD4+ T cells in the same compartment (r = 0.54, P = 0.05) and increased CD4/CD8 ratio in peripheral blood (r = 0.49, P = 0.05). There were no corresponding changes in the sigmoid colon and no changes in fecal microbiome. Probiotic intervention did not affect peripheral blood CD4 count, viral load, or soluble markers of inflammation and microbial translocation. CONCLUSIONS: Probiotics induced segment-specific changes in the terminal ileum but did not affect systemic CD4 counts in INRs. Further clinical studies are warranted to recommend probiotics to INRs.

A biliary immune landscape map of primary sclerosing cholangitis reveals a dominant network of neutrophils and tissue-resident T cells.

The human biliary system, a mucosal barrier tissue connecting the liver and intestine, is an organ often affected by serious inflammatory and malignant diseases. Although these diseases are linked to immunological processes, the biliary system represents an unexplored immunological niche. By combining endoscopy-guided sampling of the biliary tree with a high-dimensional analysis approach, comprehensive mapping of the human biliary immunological landscape in patients with primary sclerosing cholangitis (PSC), a severe biliary inflammatory disease, was conducted. Major differences in immune cell composition in bile ducts compared to blood were revealed. Furthermore, biliary inflammation in patients with PSC was characterized by high presence of neutrophils and T cells as compared to control individuals without PSC. The biliary T cells displayed a CD103+CD69+ effector memory phenotype, a combined gut and liver homing profile, and produced interleukin-17 (IL-17) and IL-22. Biliary neutrophil infiltration in PSC associated with CXCL8, possibly produced by resident T cells, and CXCL16 was linked to the enrichment of T cells. This study uncovers the immunological niche of human bile ducts, defines a local immune network between neutrophils and biliary-resident T cells in PSC, and provides a resource for future studies of the immune responses in biliary disorders.

Gut Microbiota-Dependent Trimethylamine N-Oxide Associates With Inflammation in Common Variable Immunodeficiency.

A substantial proportion of patients with common variable immunodeficiency (CVID) have inflammatory and autoimmune complications of unknown etiology. We have previously shown that systemic inflammation in CVID correlates with their gut microbial dysbiosis. The gut microbiota dependent metabolite trimethylamine N-oxide (TMAO) has been linked to several metabolic and inflammatory disorders, but has hitherto not been investigated in relation to CVID. We hypothesized that TMAO is involved in systemic inflammation in CVID. To explore this, we measured plasma concentrations of TMAO, inflammatory markers, and lipopolysaccharide (LPS) in 104 CVID patients and 30 controls. Gut microbiota profiles and the bacterial genes CutC and CntA, which encode enzymes that can convert dietary metabolites to trimethylamine in the colon, were examined in fecal samples from 40 CVID patients and 86 controls. Furthermore, a food frequency questionnaire and the effect of oral antibiotic rifaximin on plasma TMAO concentrations were explored in these 40 patients. We found CVID patients to have higher plasma concentrations of TMAO than controls (TMAO 5.0 [2.9-8.6] vs. 3.2 [2.2-6.3], p = 0.022, median with IQR). The TMAO concentration correlated positively with tumor necrosis factor (p = 0.008, rho = 0.26), interleukin-12 (p = 0.012, rho = 0.25) and LPS (p = 0.034, rho = 0.21). Dietary intake of meat (p = 0.678), fish (p = 0.715), egg (p = 0.138), dairy products (p = 0.284), and fiber (p = 0.767) did not significantly impact on the TMAO concentrations in plasma, nor did a 2-week course of the oral antibiotic rifaximin (p = 0.975). However, plasma TMAO concentrations correlated positively with gut microbial abundance of Gammaproteobacteria (p = 0.021, rho = 0.36). Bacterial gene CntA was present in significantly more CVID samples (75%) than controls (53%), p = 0.020, potentially related to the increased abundance of Gammaproteobacteria in these samples. The current study demonstrates that elevated TMAO concentrations are associated with systemic inflammation and increased gut microbial abundance of Gammaproteobacteria in CVID patients, suggesting that TMAO could be a link between gut microbial dysbiosis and systemic inflammation. Gut microbiota composition could thus be a potential therapeutic target to reduce systemic inflammation in CVID.

Impact of Human Immunodeficiency Virus-Related Gut Microbiota Alterations on Metabolic Comorbid Conditions.

BACKGROUND: We aimed to identify a human immunodeficiency virus (HIV)-related microbiota signature, independent of sexual preferences and demographic confounders, in order to assess a possible impact of the microbiome on metabolic comorbid conditions. METHODS: Bacterial 16S ribosomal RNA analyses were performed on stool samples from 405 HIV-infected and 111 uninfected participants of the Copenhagen Comorbidity in HIV Infection (COCOMO) study. Individuals were stratified according to sexual behavior (men who have sex with men [MSM] vs non-MSM). RESULTS: After excluding MSM-associated microbiota traits and adjusting for confounders, we identified an HIV-related microbiota signature, consisting of lower biodiversity, increased relative abundance of the bacterial clades Gammaproteobacteria and Desulfovibrionaceae and decrease in several Clostridia. This microbiota profile was associated with a 2-fold excess risk of metabolic syndrome, driven by increase in Desulfovibrionaceae and decrease in Clostridia (Butyrivibrio, Coprococcus 2, Lachnospiraceae UCG-001 and CAG-56). This association was accentuated (5-fold excess risk) in individuals with previous severe immunodeficiency, which also modified the association between HIV-related microbiota signature and visceral adipose tissue (VAT) area (P for interaction = .01). Accordingly, HIV-related microbiota was associated with 30-cm2 larger VAT in individuals with history of severe immunodeficiency, but not in those without. CONCLUSION: The HIV-related microbiota was associated with increased risk of metabolic syndrome and VAT accumulation, particularly in individuals with previous severe immunodeficiency, driven by increased Desulfovibrionaceae and lower abundance of several Clostridia. Our findings suggest a potential interplay between HIV-related microbiota, immune dysfunction and metabolic comorbid conditions. Interventions targeting the gut microbiome may be warranted to reduce cardiovascular risk, particularly in individuals with previous immunodeficiency.

Effect of Lactobacillus rhamnosus GG Supplementation on Intestinal Inflammation Assessed by PET/MRI Scans and Gut Microbiota Composition in HIV-Infected Individuals.

BACKGROUND: Alterations in the gut microbiome have been associated with inflammation and increased cardiovascular risk in HIV-infected individuals. The aim of this study was to investigate the effects of the probiotic strain Lactobacillus rhamnosus GG (LGG) on intestinal inflammation, gut microbiota composition, and systemic markers of microbial translocation and inflammation in HIV-infected individuals. METHODS: This prospective, clinical interventional trial included 45 individuals [15 combination antiretroviral treatment (cART) naive and 30 cART treated] who ingested LGG twice daily at a dosage of 6 × 109 colony-forming units per capsule for a period of 8 weeks. Intestinal inflammation was assessed using F-2-fluoro-2-deoxy-D-glucose positron emission tomography/magnetic resonance imaging (F-FDG PET/MRI) scans in 15 individuals. Gut microbiota composition (V3-V4 region of the 16s rRNA gene) and markers of microbial translocation and inflammation (lipopolysaccharide, sCD14, sCD163, sCD25, high-sensitive CRP, IL-6, and tumor necrosis factor-alpha) were analyzed at baseline and after intervention. RESULTS: At baseline, evidence of intestinal inflammation was found in 75% of the participants, with no significant differences between cART-naive and cART-treated individuals. After LGG supplementation, a decrease in intestinal inflammation was detected on PET/MRI (-0.3 mean difference in the combined activity grade score from 6 regions, P = 0.006), along with a reduction of Enterobacteriaceae (P = 0.018) and Erysipelotrichaceae (P = 0.037) in the gut microbiome, with reduced Enterobacteriaceae among individuals with decreased F-FDG uptake on PET/MRI (P = 0.048). No changes were observed for soluble markers of microbial translocation and inflammation. CONCLUSIONS: A decrease in intestinal inflammation was found in HIV-infected individuals after ingestion of LGG along with a reduced abundance of Enterobacteriaceae, which may explain the local anti-inflammatory effect in the gut.

Guanylate Cyclase C Activation Shapes the Intestinal Microbiota in Patients with Familial Diarrhea and Increased Susceptibility for Crohn's Disease.

BACKGROUND: With 25% prevalence of Crohn's disease, Familial GUCY2C diarrhea syndrome (FGDS) is a monogenic disorder potentially suited to study initiating factors in inflammatory bowel disease (IBD). We aimed to characterize the impact of an activating GUCY2C mutation on the gut microbiota in patients with FGDS controlling for Crohn's disease status and to determine whether changes share features with those observed in unrelated patients with IBD. METHODS: Bacterial DNA from fecal samples collected from patients with FGDS (N = 20), healthy relatives (N = 11), unrelated healthy individuals (N = 263), and IBD controls (N = 46) was subjected to sequencing of the V3-V4 region of the 16S rRNA gene to determine gut microbiota composition. Food frequency questionnaires were obtained from patients with FGDS and their relatives. RESULTS: Compared with healthy controls, FGDS displayed prominent changes in many microbial lineages including increase in Enterobacteriaceae, loss of Bifidobacterium and Faecalibacterium prausnitzii but an unchanged intraindividual (alpha) diversity. The depletion of F. prausnitzii is in line with what is typically observed in Crohn's disease. There was no significant difference in the dietary profile between the patients and related controls. The gut microbiota in related and unrelated healthy controls was also similar, suggesting that diet and familial factors do not explain the gut microbiota alterations in FGDS. CONCLUSIONS: The findings support that the activating mutation in GUCY2C creates an intestinal environment with a major influence on the microbiota, which could contribute to the increased susceptibility to IBD in patients with FGDS.

Patient Age, Sex, and Inflammatory Bowel Disease Phenotype Associate With Course of Primary Sclerosing Cholangitis.

BACKGROUND & AIMS: Primary sclerosing cholangitis (PSC) is an orphan hepatobiliary disorder associated with inflammatory bowel disease (IBD). We aimed to estimate the risk of disease progression based on distinct clinical phenotypes in a large international cohort of patients with PSC. METHODS: We performed a retrospective outcome analysis of patients diagnosed with PSC from 1980 through 2010 at 37 centers in Europe, North America, and Australia. For each patient, we collected data on sex, clinician-reported age at and date of PSC and IBD diagnoses, phenotypes of IBD and PSC, and date and indication of IBD-related surgeries. The primary and secondary endpoints were liver transplantation or death (LTD) and hepatopancreatobiliary malignancy, respectively. Cox proportional hazards models were applied to determine the effects of individual covariates on rates of clinical events, with time-to-event analysis ascertained through Kaplan-Meier estimates. RESULTS: Of the 7121 patients in the cohort, 2616 met the primary endpoint (median time to event of 14.5 years) and 721 developed hepatopancreatobiliary malignancy. The most common malignancy was cholangiocarcinoma (n = 594); patients of advanced age at diagnosis had an increased incidence compared with younger patients (incidence rate: 1.2 per 100 patient-years for patients younger than 20 years old, 6.0 per 100 patient-years for patients 21-30 years old, 9.0 per 100 patient-years for patients 31-40 years old, 14.0 per 100 patient-years for patients 41-50 years old, 15.2 per 100 patient-years for patients 51-60 years old, and 21.0 per 100 patient-years for patients older than 60 years). Of all patients with PSC studied, 65.5% were men, 89.8% had classical or large-duct disease, and 70.0% developed IBD at some point. Assessing the development of IBD as a time-dependent covariate, Crohn's disease and no IBD (both vs ulcerative colitis) were associated with a lower risk of LTD (unadjusted hazard ratio [HR], 0.62; P < .001 and HR, 0.90; P = .03, respectively) and malignancy (HR, 0.68; P = .008 and HR, 0.77; P = .004, respectively). Small-duct PSC was associated with a lower risk of LTD or malignancy compared with classic PSC (HR, 0.30 and HR, 0.15, respectively; both P < .001). Female sex was also associated with a lower risk of LTD or malignancy (HR, 0.88; P = .002 and HR, 0.68; P < .001, respectively). In multivariable analyses assessing the primary endpoint, small-duct PSC characterized a low-risk phenotype in both sexes (adjusted HR for men, 0.23; P < .001 and adjusted HR for women, 0.48; P = .003). Conversely, patients with ulcerative colitis had an increased risk of liver disease progression compared with patients with Crohn's disease (HR, 1.56; P < .001) or no IBD (HR, 1.15; P = .002). CONCLUSIONS: In an analysis of data from individual patients with PSC worldwide, we found significant variation in clinical course associated with age at diagnosis, sex, and ductal and IBD subtypes. The survival estimates provided might be used to estimate risk levels for patients with PSC and select patients for clinical trials.

Gut and liver T-cells of common clonal origin in primary sclerosing cholangitis-inflammatory bowel disease.

BACKGROUND & AIMS: Recruitment of gut-derived memory T-cells to the liver is believed to drive hepatic inflammation in primary sclerosing cholangitis (PSC). However, whether gut-infiltrating and liver-infiltrating T-cells share T cell receptors (TCRs) and antigenic specificities is unknown. We used paired gut and liver samples from PSC patients with concurrent inflammatory bowel disease (PSC-IBD), and normal tissue samples from colon cancer controls, to assess potential T cell clonotype overlap between the two compartments. METHODS: High-throughput sequencing of TCRß repertoires was applied on matched colon, liver and blood samples from patients with PSC-IBD (n=10), and on paired tumor-adjacent normal gut and liver tissue samples from colon cancer patients (n=10). RESULTS: An average of 9.7% (range: 4.7-19.9%) memory T cell clonotypes overlapped in paired PSC-IBD affected gut and liver samples, after excluding clonotypes present at similar frequencies in blood. Shared clonotypes constituted on average 16.0% (range: 8.7-32.6%) and 15.0% (range: 5.9-26.3%) of the liver and gut memory T-cells, respectively. A significantly higher overlap was observed between paired PSC-IBD affected samples (8.7%, p=0.0007) compared to paired normal gut and liver samples (3.6%), after downsampling to equal number of reads. CONCLUSION: Memory T-cells of common clonal origin were detected in paired gut and liver samples of patients with PSC-IBD. Our data indicate that this is related to PSC-IBD pathogenesis, suggesting that memory T-cells driven by shared antigens are present in the gut and liver of PSC-IBD patients. Our findings support efforts to therapeutically target memory T cell recruitment in PSC-IBD. LAY SUMMARY: Primary sclerosing cholangitis (PSC) is a devastating liver disease strongly associated with inflammatory bowel disease (IBD). The cause of PSC is unknown, but it has been suggested that the immune reactions in the gut and the liver are connected. Our data demonstrate for the first time that a proportion of the T-cells in the gut and the liver react to similar triggers, and that this proportion is particularly high in patients with PSC and IBD.

A Cross-Sectional Study of the Prevalence of Gastrointestinal Symptoms and Pathology in Patients With Common Variable Immunodeficiency.

OBJECTIVES: The objective of this study was to study the prevalence of gastrointestinal (GI) symptoms and histopathology in patients with common variable immunodeficiency (CVID) as well as linking the findings to GI infections and markers of systemic immune activation. METHODS: In this cross-sectional study, we addressed GI symptoms in 103 patients and GI histopathological findings in 53 patients who underwent upper and lower endoscopic examination. The most frequent histopathological findings were linked to GI symptoms, B-cell phenotype, and markers of systemic immune activation (soluble (s)CD14, sCD25, and sCD163). Microarray analysis compared "celiac-like disease" in CVID to celiac disease. Screening for selected bacterial and viral infections in fecal samples and gut mucosal biopsies was performed. RESULTS: The main findings of this study were as follows: most common GI symptoms were bloating (34%), pain (30%), and diarrhea (26%). The most frequent histopathological findings were increased intraepithelial lymphocytes in the descending part of the duodenum, i.e., "celiac-like disease" (46% of patients), decreased numbers of plasma cells in GI tract mucosa (62%), and lymphoid hyperplasia (38%), none of which were associated with GI symptoms. Reduced plasma cells in GI mucosa were associated with B-cell phenotypic characteristics of CVID, and increased serum levels of sCD14 (P=0.025), sCD25 (P=0.01), and sCD163 (P=0.04). Microarray analyses distinguished between CVID patients with "celiac-like disease" and celiac disease. Positive tests for bacterial and viral infections were scarce both in fecal samples and gut mucosal biopsies, including PCR test for norovirus in biopsy specimens (0 positive tests). CONCLUSIONS: In conclusion, GI pathology is common in CVID, but does not necessarily cause symptoms. However, reduced plasma cells in GI mucosa were linked to systemic immune activation, "celiac-like disease" in CVID and true celiac disease appear to be different disease entities, as assessed by gene expression, and infections (including norovirus) are rarely a cause of the CVID enteropathy.

Extended analysis of a genome-wide association study in primary sclerosing cholangitis detects multiple novel risk loci.

BACKGROUND & AIMS: A limited number of genetic risk factors have been reported in primary sclerosing cholangitis (PSC). To discover further genetic susceptibility factors for PSC, we followed up on a second tier of single nucleotide polymorphisms (SNPs) from a genome-wide association study (GWAS). METHODS: We analyzed 45 SNPs in 1221 PSC cases and 3508 controls. The association results from the replication analysis and the original GWAS (715 PSC cases and 2962 controls) were combined in a meta-analysis comprising 1936 PSC cases and 6470 controls. We performed an analysis of bile microbial community composition in 39 PSC patients by 16S rRNA sequencing. RESULTS: Seventeen SNPs representing 12 distinct genetic loci achieved nominal significance (p(replication) <0.05) in the replication. The most robust novel association was detected at chromosome 1p36 (rs3748816; p(combined)=2.1 × 10(-8)) where the MMEL1 and TNFRSF14 genes represent potential disease genes. Eight additional novel loci showed suggestive evidence of association (p(repl) <0.05). FUT2 at chromosome 19q13 (rs602662; p(comb)=1.9 × 10(-6), rs281377; p(comb)=2.1 × 10(-6) and rs601338; p(comb)=2.7 × 10(-6)) is notable due to its implication in altered susceptibility to infectious agents. We found that FUT2 secretor status and genotype defined by rs601338 significantly influence biliary microbial community composition in PSC patients. CONCLUSIONS: We identify multiple new PSC risk loci by extended analysis of a PSC GWAS. FUT2 genotype needs to be taken into account when assessing the influence of microbiota on biliary pathology in PSC.

Genome-wide association analysis in primary sclerosing cholangitis identifies two non-HLA susceptibility loci.

Primary sclerosing cholangitis (PSC) is a chronic bile duct disease affecting 2.4-7.5% of individuals with inflammatory bowel disease. We performed a genome-wide association analysis of 2,466,182 SNPs in 715 individuals with PSC and 2,962 controls, followed by replication in 1,025 PSC cases and 2,174 controls. We detected non-HLA associations at rs3197999 in MST1 and rs6720394 near BCL2L11 (combined P = 1.1 × 10⁻¹6 and P = 4.1 × 10⁻8, respectively).

Small intestinal neuroendocrine tumors: prognostic factors and survival.

OBJECTIVE: Small intestinal neuroendocrine tumors (SI-NETs) make up 38% of gastroenteropancreatic neuroendocrine tumors. We report our experience with SI-NETs at the National Center for Neuroendocrine Tumors in Norway, focusing on prognostic factors and survival. MATERIAL AND METHODS: The medical records of 258 patients with SI-NETs diagnosed between 1983 and 2007 were retrospectively reviewed. Demographic, clinical and tumor characteristics were registered in a database. RESULTS: Median age at diagnosis was 62 years (range 28-84); 53% of patients were men. Median survival was 9.3 years [95% confidence interval (CI) 7.6; 10.8]. Survival did not improve for patients diagnosed between 1998 and 2007 compared with those diagnosed between 1990 and 1997 (p=0.44), median survival 8.1 [7.1;9.1] versus 6.8 [4.0; 9.5] years. Overall 5-year survival was 72%, while expected 5-year survival in the general population was 92%. The corresponding relative 5-year survival for the patient group was 78%. Distant metastases, urinary 5-hydroxyindoleacetic acid ratio > or =3.7 times the upper limit of normal, chromogranin A ratio > or =6.2 times the upper limit of normal, age > or =64, male gender, carcinoid heart disease, and Ki-67 > or =5% were associated with decreased survival. Using multivariate analysis, only distant metastases (hazard ratio (HR) 1.98 [1.04;3.76], p=0.04), chromogranin A ratio > or =6.2 (HR 1.90 [1.12; 3.20], p=0.02), and age > or =64 (3.12 [1.93; 5.04], p<0.001) remained independent predictors. CONCLUSIONS: Survival did not improve over the study period. Overall and relative 5-year survival compared favorably with that in population-based studies. Distant metastases, elevated chromogranin A levels, and advanced age were the only independent predictors of poor survival.