Tailoring follow-up endoscopy in patients with severe oesophagitis.

Objective: We aimed to investigate the clinical utility of follow-up oesophagogastroduodenoscopy (OGD2) in patients with severe oesophagitis (Los Angeles grades C or D) through evaluating the yield of Barrett's oesophagus (BO), cancer, dysplasia and strictures. Second, we aimed to determine if the Clinical Frailty Scale (CFS) may be used to identify patients to undergo OGD2s. Design/method: Patients in NHS Lothian with an index OGD (OGD1) diagnosis of severe oesophagitis between 1 January 2014 and 31 December 2015 were identified. Univariate analysis identified factors associated with grade. Patients were stratified by frailty and a diagnosis of stricture, cancer, dysplasia and BO. Results: In total 964 patients were diagnosed with severe oesophagitis, 61.7% grade C and 38.3% grade D. The diagnostic yield of new pathology at OGD2 was 13.2% (n=51), new strictures (2.3%), dysplasia (0.5%), cancer (0.3%) and BO (10.1%). A total of 140 patients had clinical frailty (CFS score ≥5), 88.6% of which were deceased at review (median of 76 months). In total 16.4% of frail patients underwent OGD2s and five new pathologies were diagnosed, none of which were significantly associated with grade. Among non-frail patients at OGD2, BO was the only pathology more common (p=0.010) in patients with grade D. Rates of cancer, dysplasia and strictures did not vary significantly between grades. Conclusion: Our data demonstrate that OGD2s in patients with severe oesophagitis may be tailored according to clinical frailty and only be offered to non-frail patients. In non-frail patients OGD2s have similar pick-up rates of sinister pathology in both grades of severe oesophagitis.

Risk stratifying gastric ulcers: development and validation of a scoring system.

Objective: Debate is ongoing regarding the need for universal endoscopic follow-up to ensure gastric ulcer healing. We aimed to assess the value of follow-up oesophago-gastro-duodenoscopies (OGDs) for gastric ulcer healing and stratify patients according to risk of malignancy by developing a risk score. Design/method: All patients in National Health Service (NHS) Lothian with an index OGD and a diagnosis of gastric ulcer between 1 January 2014 and 31 December 2018 were identified. Data were analysed with logistic regression to identify factors significantly associated with a diagnosis of cancer; a risk score was derived and externally validated. Results: 778 patients were identified and 60.3% (469/778) of patients had a follow-up OGD. 8.6% (66/778) of patients were diagnosed with cancer. No cases of cancer were found on follow-up OGD of a benign appearing ulcer with negative biopsies. Macroscopic suspicion of malignancy was present at index OGD in 100% (3/3) of those diagnosed with cancer on subsequent OGDs. Older age (p=0.014), increased ulcer size (p<0.001) and non-antral location (p=0.030) were significantly associated with malignancy. A risk score (area under the curve (AUC) 0.868, p<0.001, minimum score=0, maximum score=6) was derived from these variables. 78.0% of patients with malignant ulcers scored ≥3, only 15.8% with benign ulcers scored ≥3 (negative predictive value (NPV) 97.4%). External validation yielded an AUC of 0.862 (p<0.001) and NPV of 98.6%; 84.0% of those with malignant ulcers scored ≥3. Conclusion: Ulcers with a combination of macroscopically benign appearances, at least six negative biopsies and a low risk score do not necessarily need endoscopic follow-up.

Short-term outcomes of a COVID-adapted triage pathway for colorectal cancer detection.

AIM: The dramatic curtailment of endoscopy and CT colonography capacity during the coronavirus pandemic has adversely impacted timely diagnosis of colorectal cancer (CRC). We describe a rapidly implemented COVID-adapted diagnostic pathway to mitigate risk and maximize cancer diagnosis in patients referred with symptoms of suspected CRC. METHOD: The 'COVID-adapted pathway' integrated multiple quantitative faecal immunochemical tests (qFIT) to enrich for significant colorectal disease with judicious use of CT with oral contrast to detect gross pathology. Patients reporting 'high-risk' symptoms were triaged to qFIT+CT and the remainder underwent an initial qFIT to inform subsequent investigation. Demographic and clinical data were prospectively collected. Outcomes comprised cancer detection frequency. RESULTS: Overall, 422 patients (median age 64 years, 220 women) were triaged using this pathway. Most (84.6%) were referred as 'urgent suspicious of cancer'. Of the 422 patients, 202 (47.9%) were triaged to CT and qFIT, 211 (50.0%) to qFIT only, eight (1.9%) to outpatient clinic and one to colonoscopy. Fifteen (3.6%) declined investigation and seven (1.7%) were deemed unfit. We detected 13 cancers (3.1%), similar to the mean cancer detection rate from all referrals in 2017-2019 (3.3%). Compared with the period 1 April-31 May in 2017-2019, we observed a 43% reduction in all primary care referrals (1071 referrals expected reducing to 609). CONCLUSION: This COVID-adapted pathway mitigated the adverse effects on diagnostic capacity and detected cancer at the expected rate within those referred. However, the overall reduction in the number of referrals was substantial. The described risk-mitigating measures could be a useful adjunct whilst standard diagnostic services remain constrained due to the ongoing pandemic.

Improved high-quality colon cleansing with 1L NER1006 versus 2L polyethylene glycol + ascorbate or oral sulfate solution.

BACKGROUND & AIMS: Colonoscopy requires bowel cleansing for gut mucosa visualization; high-quality cleansing facilitates lesion detection. NER1006 is a 1L polyethylene glycol (PEG) bowel preparation. This post hoc analysis of two randomized trials investigated cleansing efficacy assessed, as in clinical practice, by site endoscopists. METHODS: Patients received NER1006, 2L PEG + ascorbate (2LPEG), or oral sulfate solution (OSS) as a 2-day evening/morning regimen (N2D) or NER1006 morning-only dosing (N1D). Treatment-blinded site endoscopists assessed cleansing using the Harefield Cleansing Scale (HCS). Analyses were conducted in a modified full analysis set, including (mFAS; n = 1378) or excluding (mFAS2; n = 1319) imputed failures, and in patients with 100% treatment adherence (mFAS100; n = 1047). Overall cleansing success (HCS grade A/B), overall high-quality cleansing (HCS grade A), and high-quality segments (HCS 3-4) per treatment population were analyzed. RESULTS: Overall cleansing success was higher with N2D than 2LPEG (92.7-97.5% vs. 87.9-93.0%), and more patients had overall high-quality cleansing with N2D and N1D than 2LPEG (68.0-72.1% and 64.0-68.4% vs. 50.7-56.0%). Without imputed failures, N2D delivered more overall high-quality cleansing than OSS (74.5-77.3% vs. 67.8-69.8%). More high-quality segments were demonstrated with N2D and N1D versus 2 LPEG (82.5-87.1% and 79.4-84.4% vs. 70.4-76.3%) and with N2D versus OSS (82.7-89.5% vs. 78.1-84.4%). CONCLUSION: When assessed by site endoscopists, NER1006 delivers greater high-quality cleansing than 2LPEG or OSS.

Higher Adalimumab Drug Levels During Maintenance Therapy for Crohn's Disease Are Associated With Biologic Remission.

BACKGROUND: Adalimumab is an established treatment for Crohn's disease. Limited data are available regarding the relationship between adalimumab drug levels and serum/fecal markers of gut inflammation. We therefore aimed to characterize the relationship between adalimumab levels and biologic remission during maintenance therapy. METHODS: A single-center prospective cross-sectional study was undertaken on Crohn's disease patients who had received adalimumab therapy for a minimum of 12 weeks after induction. Data on clinical activity (Harvey-Bradshaw Index), C-reactive protein (CRP), adalimumab drug and antibody levels, and fecal calprotectin were collected. Biologic remission was defined as a CRP <5 mg/L and fecal calprotectin <250 µg/g. Adalimumab drug and antibody levels were processed using the Immundiagnostik monitor enzyme-linked immunosorbent assay. RESULTS: One hundred fifty-two patients had drug and antibody samples matched with CRP and fecal calprotectin. Patients in biologic remission had significantly higher adalimumab levels compared with others (12.0 µg/mL vs 8.0 µg/mL, P < 0.0001). Receiver operating characteristic curve analysis demonstrated an optimal adalimumab level of >8.5 µg/mL (sensitivity, 82.2%; specificity, 55.7%; likelihood ratio, 1.9) for predicting biologic remission. Multivariable logistic regression revealed that adalimumab levels >8.5 µg/mL were independently associated with biologic remission (odds ratio, 5.27; 95% confidence interval, 2.43-11.44; P < 0.0001). CONCLUSIONS: Higher adalimumab levels are associated with biologic remission. An optimal level of >8.5 µg/mL was identified.

Implementation of CT-P13 via a Managed Switch Programme in Crohn's Disease: 12-Month Real-World Outcomes.

BACKGROUND: Switching from Remicade to CT-P13 allows for significant cost savings and has been shown to be non-inferior to continued therapy with Remicade for the treatment of Crohn's disease. AIM: The aim of this work was to prospectively evaluate clinical outcomes in a cohort of patients with Crohn's disease switching from Remicade to CT-P13. METHODS: A prospective service evaluation was performed. The Harvey-Bradshaw index, CRP, faecal calprotectin and serum for infliximab/antibody levels were collected prior to patients' final Remicade infusion and at 6 and 12 months after switching to CT-P13 as part of routine clinical care. All adverse events during follow-up were also recorded. RESULTS: One hundred and ten patients on Remicade switched to CT-P13. No significant difference was observed between the Harvey-Bradshaw Index (p = 0.07), CRP (p = 0.13), faecal calprotectin (p = 0.25) or trough infliximab levels (p = 0.47) comparing before and at 6 and 12 months after the switch to CT-P13. Seven patients developed new infliximab antibodies after switching from Remicade to CT-P13. The majority of patients remained on CT-P13 at 12 months (84.5%) and the rate of adverse events and serious adverse events was 53.8 and 13.5 per 100 patient-years of follow-up, respectively. Switching to CT-P13 resulted in a cost saving of approximately 46.4%. CONCLUSION: The transition to CT-P13 from Remicade for the treatment of Crohn's disease is safe and has no negative effect on clinical outcomes at 12 months.

Colonoscopy quality with Entonox®vs intravenous conscious sedation: 18608 colonoscopy retrospective study.

AIM: To compare colonoscopy quality with nitrous oxide gas (Entonox®) against intravenous conscious sedation using midazolam plus opioid. METHODS: A retrospective analysis was performed on a prospectively held database of 18608 colonoscopies carried out in Lothian health board hospitals between July 2013 and January 2016. The quality of colonoscopies performed with Entonox was compared to intravenous conscious sedation (abbreviated in this article as IVM). Furthermore, the quality of colonoscopies performed with an unmedicated group was compared to IVM. The study used the following key markers of colonoscopy quality: (1) patient comfort scores; (2) caecal intubation rates (CIRs); and (3) polyp detection rates (PDRs). We used binary logistic regression to model the data. RESULTS: There was no difference in the rate of moderate-to-extreme discomfort between the Entonox and IVM groups (17.9% vs 18.8%; OR = 1.06, 95%CI: 0.95-1.18, P = 0.27). Patients in the unmedicated group were less likely to experience moderate-to-extreme discomfort than those in the IVM group (11.4% vs 18.8%; OR = 0.71, 95%CI: 0.60-0.83, P < 0.001). There was no difference in caecal intubation between the Entonox and IVM groups (94.4% vs 93.7%; OR = 1.08, 95%CI: 0.92-1.28, P = 0.34). There was no difference in caecal intubation between the unmedicated and IVM groups (94.2% vs 93.7%; OR = 0.98, 95%CI: 0.79-1.22, P = 0.87). Polyp detection in the Entonox group was not different from IVM group (35.0% vs 33.1%; OR = 1.01, 95%CI: 0.93-1.10, P = 0.79). Polyp detection in the unmedicated group was not significantly different from the IVM group (37.4% vs 33.1%; OR = 0.97, 95%CI: 0.87-1.08, P = 0.60). CONCLUSION: The use of Entonox was not associated with lower colonoscopy quality when compared to intravenous conscious sedation using midazolam plus opioid.

Two-stage genome-wide methylation profiling in childhood-onset Crohn's Disease implicates epigenetic alterations at the VMP1/MIR21 and HLA loci.

BACKGROUND: As a result of technological and analytical advances, genome-wide characterization of key epigenetic alterations is now feasible in complex diseases. We hypothesized that this may provide important insights into gene-environmental interactions in Crohn's disease (CD) and is especially pertinent to early onset disease. METHODS: The Illumina 450K platform was applied to assess epigenome-wide methylation profiles in circulating leukocyte DNA in discovery and replication pediatric CD cohorts and controls. Data were corrected for differential leukocyte proportions. Targeted replication was performed in adults using pyrosequencing. Methylation changes were correlated with gene expression in blood and intestinal mucosa. RESULTS: We identified 65 individual CpG sites with methylation alterations achieving epigenome-wide significance after Bonferroni correction (P < 1.1 × 10(-7)), and 19 differently methylated regions displaying unidirectional methylation change. There was a highly significant enrichment of methylation changes around GWAS single nucleotide polymorphisms (P = 3.7 × 10(-7)), notably the HLA region and MIR21. Two-locus discriminant analysis in the discovery cohort predicted disease in the pediatric replication cohort with high accuracy (area under the curve, 0.98). The findings strongly implicate the transcriptional start site of MIR21 as a region of extended epigenetic alteration, containing the most significant individual probes (P = 1.97 × 10(-15)) within a GWAS risk locus. In extension studies, we confirmed hypomethylation of MIR21 in adults (P = 6.6 × 10(-5), n = 172) and show increased mRNA expression in leukocytes (P < 0.005, n = 66) and in the inflamed intestine (P = 1.4 × 10(-6), n = 99). CONCLUSIONS: We demonstrate highly significant and replicable differences in DNA methylation in CD, defining the disease-associated epigenome. The data strongly implicate known GWAS loci, with compelling evidence implicating MIR21 and the HLA region.

Three-dimensional representation software as image enhancement tool in small-bowel capsule endoscopy: a feasibility study.

BACKGROUND: Three-dimensional imaging in capsule endoscopy is not currently feasible due to hardware limitations. However, software algorithms that enable three-dimensional reconstruction in capsule endoscopy are available. METHODS: Feasibility study. A phantom was designed to test the accuracy of three-dimensional reconstruction. Thereafter, 192 small-bowel capsule endoscopy images (of vascular: 50; inflammatory: 73; protruding structures: 69) were reviewed with the aid of a purpose-built three-dimensional reconstruction software. Seven endoscopists rated visualisation improved or non-improved. Subgroup analyses performed for diagnostic category, diagnosis, image surface morphology and colour and SBCE equipment used (PillCam(®) vs. MiroCam(®)). RESULTS: Overall, phantom experiments showed that the three-dimensional reconstruction software was accurate at 90% of red, 70% of yellow and 45% of white phantom models. Enhanced visualisation for 56% of vascular, 23% of inflammatory and <10% of protruding structures was noted (P=0.007, 0.172 and 0.008, respectively). Furthermore, three-dimensional software application enhanced 53.7% of red, 21.8% of white, 17.3% of red and white, and 9.2% of images of lesions with colour similar to that of the surrounding mucosa, P<0.0001. CONCLUSIONS: Application of a three-dimensional reconstruction software in capsule endoscopy leads to image enhancement for a significant proportion of vascular, but less so for inflammatory and protruding lesions. Until optics technology allows hardware-enabled three-dimensional reconstruction, it seems a plausible alternative.

TLE1 modifies the effects of NOD2 in the pathogenesis of Crohn's disease.

BACKGROUND & AIMS: The mechanisms by which specific mutations in NOD2/CARD15 increase the risk for Crohn's disease (CD) are unclear. We identified proteins that interact with NOD2 and investigated them by expression, genetic, and functional analyses. METHODS: By using a yeast 2-hybrid screen of an intestinal epithelial library, we identified proteins that interact with NOD2 and confirmed the interactions in mammalian cells using co-immunoprecipitation. We used microarray analysis to analyze gene expression patterns in 302 intestinal biopsy samples (129 from patients with ulcerative colitis [UC], 106 with CD, and 67 controls). Eighty single-nucleotide polymorphisms within the genes that encoded 6 interacting proteins were genotyped in a discovery cohort (869 cases of inflammatory bowel disease [IBD], 885 controls) and a replication cohort (504 patients with IBD, 713 controls). We investigated interaction between transducin-like enhancer of split 1 (TLE1) and NOD2 in HEK293 cells. RESULTS: We identified 6 NOD2-interacting proteins (TLE1, UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 2 [GALNT2], HIV-1 Tat interactive protein [HTATIP], Vimentin, fission 1 (mitochondrial outer membrane) homolog [FIS1], and protein phosphatase 2, regulatory subunit B', epsilon isoform [PPP2R5E]). Of these, expression of GALNT2 (CD, P = .004) and vimentin (CD, P = .006; UC, P = .0025) was altered in patients with IBD compared with controls. Single-nucleotide polymorphisms within TLE1 were associated with susceptibility to CD, specifically with ileal disease (rs6559629, P = 3.1 × 10⁻5; odds ratio, 1.45). The TLE1 risk allele is required for susceptibility to CD in carriers of NOD2 mutations. In cells, TLE1 and NOD2 co-localized around the nuclear membrane and TLE1 inhibited activation of nuclear factor-κB by NOD2. CONCLUSIONS: Epistatic and biological interactions between TLE1 and NOD2 are involved in IBD pathogenesis. NOD2 might be involved in a series of pathways such as epigenetic regulation of expression (via TLE1 and HTATIP), biosynthesis of mucin (via GALNT2), apoptosis (via PPP2R5E and FIS1), and integrity of the intracellular cytoskeleton (vimentin).

Characterization of intestinal gene expression profiles in Crohn's disease by genome-wide microarray analysis.

BACKGROUND: Genome-wide microarray expression analysis creates a comprehensive picture of gene expression at the cellular level. The aim of this study was to investigate differential intestinal gene expression in patients with Crohn's disease (CD) and controls with subanalysis of confirmed CD susceptibility genes, associated pathways, and cell lineage. METHODS: In all, 172 biopsies from 53 CD and 31 control subjects were studied. Paired endoscopic biopsies were taken at ileocolonoscopy from five specific anatomical locations including the terminal ileum (TI) for RNA extraction and histology. The 41,058 expression sequence tags were analyzed using the Agilent platform. RESULTS: Analysis of all CD biopsies versus controls showed 259 sequences were upregulated and 87 sequences were downregulated. Upregulated genes in CD included SAA1 (fold change [FC] +7.5, P = 1.47 × 10(-41)) and REGL (FC +7.3, P = 2.3 × 10(-16)), whereas cellular detoxification genes including-SLC14A2 (FC-2.49, P = 0.00002) were downregulated. In the CD TI biopsies diubiquitin (FC+11.3, P < 1 × 10(-45)), MMP3 (FC+7.4, P = 1.3 × 10(-11)), and IRTA1 (FC-11.4, P = 4.7 × 10(-12)) were differentially expressed compared to controls. In the colon SAA1 (FC+6.3, P = 5.3 × 10(-8)) was upregulated and thymic stromal lymphopoietin (TSLP) (FC-2.3, P = 2.7 × 10(-6)) was downregulated comparing noninflamed CD and control biopsies, and the colonic inflammatory CD signature was characterized by downregulation of the organic solute carriers-SLC38A4, SLC26A2, and OST alpha. Of CD susceptibility genes identified by genome-wide association scan IL-23A, JAK2, and STAT3 were upregulated in the CD group, confirming the dysregulation of Th17 signaling. CONCLUSIONS: These data characterize the dysregulation of a series of specific inflammatory pathways highlighting potential pathogenic mechanisms as well as areas for translation to therapeutic targets.

Association of FcgR2a, but not FcgR3a, with inflammatory bowel diseases across three Caucasian populations.

BACKGROUND: The Fc receptors II and III (FcgR2a, and FcgR3a) play a crucial role in the regulation of the immune response. The FcgR2a*519GG and FcgR3a*559CC genotypes have been associated with several autoimmune diseases including systemic lupus erythematosus, rheumatoid arthritis, nephritis, and possibly to type I diabetes, and celiac disease. In a large multicenter, two-stage study of 6570 people, we tested whether the FcgR2a and FcgR3a genes were also involved in inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We genotyped the FcgR2a*A519G and FcgR3a*A559C functional variants in 4205 IBD patients in six well-phenotyped Caucasian IBD cohorts and 2365 ethnically matched controls recruited from the Netherlands, Spain, and New Zealand. RESULTS: In the initial Dutch study we found a significant association of FcgR2a genotypes with IBD (P-genotype = 0.02); while the FcgR2a*519GG was more common in controls (23%) than in IBD patients (18%; odds ratio [OR] = 0.75; 95% confidence interval [CI] 0.61-0.92; P = 0.004). This association was corroborated by a combined analysis across all the study populations (Mantel-Haenszel [MH] OR = 0.84; 0.74-0.95; P = 0.005) in the next stage. The Fcgr2a*GG genotype was associated with both UC (MH-OR = 0.84; 0.72-0.97; P = 0.01) and CD (MH-OR = 0.84; 0.73-0.97; P = 0.01), suggesting that this genotype confers a protective effect against IBD. There was no association of FcgR3a*A559C genotypes with IBD, CD, or UC in any of the three studied populations. CONCLUSIONS: The FcgR2a*519G functional variant was associated with IBD and reduced susceptibility to UC and to CD in Caucasians. There was no association between FcgR3a*5A559C and IBD, CD or UC.

Dysregulation of human beta-defensin-2 protein in inflammatory bowel disease.

BACKGROUND: Human beta-defensin-2 (HBD2) is an antimicrobial peptide implicated in the pathogenesis of inflammatory bowel disease (IBD). Low copy number and concomitant low mRNA expression of the HBD2 gene have been implicated in susceptibility to colonic Crohn's Disease (CD). We investigated the colonic distribution of HBD2 mRNA expression, and the contributions of genetic and environmental factors on HBD2 protein production. METHODOLOGY/PRINCIPAL FINDINGS: We examined HBD2 mRNA expression at three colonic locations by microarray analysis of biopsies from 151 patients (53 CD, 67 ulcerative colitis [UC], 31 controls). We investigated environmental and genetic influences on HBD2 protein production using ex vivo cultured sigmoid colon biopsies from 69 patients (22 CD, 26 UC, 21 controls) stimulated with lipopolysaccharide (LPS) and/or nicotine for 24 hours. HBD2 and cytokines were measured in culture supernatants. Using DNA samples from these patients, regions in the HBD2 gene promoter were sequenced for NF-kappaB binding-sites and HBD2 gene copy number was determined. HBD2 mRNA expression was highest in inflamed (vs. uninflamed p = 0.0122) ascending colon in CD and in inflamed (vs. uninflamed p<0.0001) sigmoid colon in UC. HBD2 protein production was increased in inflamed UC biopsies (p = 0.0078). There was no difference in HBD2 protein production from unstimulated biopsies of CD, UC and controls. LPS-induced HBD2 production was significantly increased in CD (p = 0.0375) but not UC (p = 0.2017); this LPS-induced response was augmented by nicotine in UC (p = 0.0308) but not CD (p = 0.6872). Nicotine alone did not affect HBD2 production. HBD2 production correlated with IL8 production in UC (p<0.001) and with IL10 in CD (p<0.05). Variations in the HBD2 promoter and HBD2 gene copy number did not affect HBD2 production. SIGNIFICANCE/CONCLUSIONS: Colonic HBD2 was dysregulated at mRNA and protein level in IBD. Inflammatory status and stimulus but not germline variations influenced these changes.

PepT1 oligopeptide transporter (SLC15A1) gene polymorphism in inflammatory bowel disease.

BACKGROUND: Human polymorphisms affecting gut epithelial barrier and interactions with bacteria predispose to the inflammatory bowel diseases (IBD) Crohn's disease (CD) and ulcerative colitis (UC). The intestinal transporter PepT1, encoded by the SLC15A1 gene, mediates intracellular uptake of bacterial products that can induce inflammation and NF-kappaB activation upon binding to NOD2, a protein often mutated in CD. Hence, we tested SLC15A1 polymorphisms for association with IBD. METHODS: Twelve SLC15A1 single nucleotide polymorphisms (SNPs) were genotyped in 1783 individuals from 2 cohorts of Swedish and Finnish IBD patients and controls. An in vitro system was set up to evaluate the potential impact of SLC15A1 polymorphism on PepT1 transporter function by quantification of NOD2-mediated activation of NF-kappaB. RESULTS: The common allele (C) of a coding polymorphism (rs2297322, Ser117Asn) was associated with CD susceptibility both in Sweden and in Finland, but with genetic effects in opposite directions (risk and protection, respectively). The best evidence of association was found in both populations when the analysis was performed on individuals not carrying NOD2 common risk alleles (Sweden allelic P = 0.0007, OR 1.97, 95% confidence interval [CI] 1.34-2.92; Finland genotype P = 0.0013, OR 0.63, 95% CI 0.44-0.90). The PepT1 variant encoded by the C allele (PepT1-Ser117) was associated with reduced signaling downstream of NOD2 (P < 0.0001 compared to Pept1-Asn117). CONCLUSIONS: A functional polymorphism in the SLC15A1 gene might be of relevance to inflammation and antibacterial responses in IBD. Whether this polymorphism truly contributes to disease susceptibility needs to be further addressed, and should stimulate additional studies in other populations.

Analysis of germline GLI1 variation implicates hedgehog signalling in the regulation of intestinal inflammatory pathways.

BACKGROUND: Ulcerative colitis (UC) and Crohn's disease (CD) are polygenic chronic inflammatory bowel diseases (IBD) of high prevalence that are associated with considerable morbidity. The hedgehog (HH) signalling pathway, which includes the transcription factor glioma-associated oncogene homolog 1 (GLI1), plays vital roles in gastrointestinal tract development, homeostasis, and malignancy. We identified a germline variation in GLI1 (within the IBD2 linkage region, 12q13) in patients with IBD. Since this IBD-associated variant encodes a GLI1 protein with reduced function and our expression studies demonstrated down-regulation of the HH response in IBD, we tested whether mice with reduced Gli1 activity demonstrate increased susceptibility to chemically induced colitis. METHODS AND FINDINGS: Using a gene-wide haplotype-tagging approach, germline GLI1 variation was examined in three independent populations of IBD patients and healthy controls from Northern Europe (Scotland, England, and Sweden) totalling over 5,000 individuals. On log-likelihood analysis, GLI1 was associated with IBD, predominantly UC, in Scotland and England (p < 0.0001). A nonsynonymous SNP (rs2228226C-->G), in exon 12 of GLI1 (Q1100E) was strongly implicated, with pooled odds ratio of 1.194 (confidence interval = 1.09-1.31, p = 0.0002). GLI1 variants were tested in vitro for transcriptional activity in luciferase assays. Q1100E falls within a conserved motif near the C terminus of GLI1; the variant GLI protein exhibited reduced transactivation function in vitro. In complementary expression studies, we noted the colonic HH response, including GLI1, patched (PTCH), and hedgehog-interacting protein (HHIP), to be down-regulated in patients with UC. Finally, Gli1(+/lacZ) mice were tested for susceptibility to dextran sodium sulphate (DSS)-induced colitis. Clinical response, histology, and expression of inflammatory cytokines and chemokines were recorded. Gli1(+/lacZ) mice rapidly developed severe intestinal inflammation, with considerable morbidity and mortality compared with wild type. Local myeloid cells were shown to be direct targets of HH signals and cytokine expression studies revealed robust up-regulation of IL-12, IL-17, and IL-23 in this model. CONCLUSIONS: HH signalling through GLI1 is required for appropriate modulation of the intestinal response to acute inflammatory challenge. Reduced GLI1 function predisposes to a heightened myeloid response to inflammatory stimuli, potentially leading to IBD.

Contribution of the IBD5 locus to Crohn's disease in the Swedish population.

OBJECTIVE: Recent data have controversially suggested that variants of the organic cation transport genes SLC22A4 (OCTN1) and SLC22A5 (OCTN2) are responsible for the contribution of IBD5 to disease susceptibility in Crohn's disease (CD). The objective of this study was to assess the contribution of the SLC22A4 variant (1672T) and SLC22A5 variant (-207C) together with three IBD5 haplotype markers in the previously uninvestigated Swedish CD population. MATERIAL AND METHODS: The study comprised 178 CD patients and 143 healthy controls (HC). Genotyping for IBD5 single nucleotide polymorphisms (SNPs) IGR2096a_1, IGR2198a_1, IGR2230a_1, SLC22A4 1672T and SLC22A5 -207C was carried out using the TaqMan system. Associations with disease susceptibility and disease phenotype were investigated. RESULTS: Strong linkage disequilibrium was observed between the investigated SNPs (D prime >0.92). IGR2096a_1 allelic frequency and homozygosity rates were associated with CD (44% CD versus 33.8% HC, p=0.008, OR=1.55 and 20% CD versus 12% HC, p=0.04, OR=1.93, respectively). Variant allelic frequency of SLC22A4, 1672T (44% versus 36%, p=0.03, OR=1.4) and homozygosity for the SLC22A4, SLC22A5 TC haplotype (1672T, -207C) (21.3% versus 12%, p=0.03, OR=1.78, population attributable risk (PAR)=11%) were associated with CD. There was no association between the allelic frequency of SLC22A5 and CD (46.6% CD versus 41.5% HC, p=0.82). The association of the TC haplotype with CD was not independent of the SNPs representing the extended IBD5 linkage interval. CONCLUSIONS: The IBD5 locus is associated with CD in the Swedish population. The strongest association is with the marker SNP IGR2096a_1, lying p-telomeric to SLC22A4 and SLC22A5. The effect of the TC haplotype was not an independent determinant in this population.

Contribution of CARD15 variants in determining susceptibility to Crohn's disease in Sweden.

OBJECTIVE: Crohn's disease (CD) is a chronic inflammatory bowel disorder caused by environmental and genetic factors. Mutations in the CARD15 gene have been associated with CD. No previous case-control CARD15 study has been performed in the Swedish population. MATERIAL AND METHODS: The study comprised of 321 individuals: 178 with CD and 143 healthy controls (HCs), all from Stockholm County. All were genotyped for the three main CD-associated CARD15 variants (R702W, G908R and 1007fs) and phenotypic associations were investigated. RESULTS: The allele frequencies of the R702W variant (4.5% CD versus 0.7% HC, p=0.008, OR = 6.8) and the G908R variant (2.0% CD versus 0% HC, p=0.045) were more common in CD patients than in controls. No significant difference in1007fs variant allele frequency was found between CD patients and controls (2.0% CD versus 1.7% HC, p = 0.8, OR = 1.1). Carriage of CARD15 variants was more common in the CD patients than in controls (15.2% CD versus 4.2% HC, p = 0.001, OR = 4.1, population attributable risk (PAR) = 11.4%). Genotype-phenotype analysis demonstrated that CARD15 variants were associated with ileal disease (p=0.0006, OR = 9.3, CI = 2.2-34) and protective for colonic CD (p = 0.01, OR = 0.18). An association between CARD15 variants and ileal CD (p=0.004, OR = 6.6) was confirmed by multivariate analyses. CONCLUSIONS: The CARD15 variants R702W and G908R, but not 1007fs, are associated with susceptibility to CD in Stockholm County. Genotype-phenotype analysis shows an association with ileal CD. The contribution of these CARD15 mutations in Swedish CD patients overall is low in relation to studies elsewhere in Central Europe and North America, but is consistent with emerging data from elsewhere in Scandinavia and in Northern Europe.

The contribution of OCTN1/2 variants within the IBD5 locus to disease susceptibility and severity in Crohn's disease.

BACKGROUND & AIMS: Recent data suggest that polymorphisms in the organic cation transporter (OCTN) genes OCTN1 (SLC22A4) and OCTN2 (SLC22A5) represent disease-causing mutations within the IBD5 locus (chromosome 5q31). We investigated associations with disease susceptibility, phenotype, and evidence for epistasis with CARD15 in 679 patients with Crohn's disease (CD) or ulcerative colitis (UC). METHODS: A total of 374 patients with CD, 305 patients with UC, and 294 healthy controls (HCs) were studied. Genotyping for single nucleotide polymorphisms IGR2096, IGR2198, and IGR2230, OCTN1 variant (SLC22A4 1672C-->T), and OCTN2 variant (SLC22A5 -207G-->C) was performed using the TaqMan system. RESULTS: The IBD5 OCTN1 and OCTN2 polymorphisms were in strong linkage disequilibrium (D', >0.959). IGR2198 variant allele frequency (49.1% vs 40.8%; P = .0046) and homozygosity (21% vs 14.8%; P = .044) were associated with CD versus HCs. Variant allelic frequency of OCTN1 (53.6% vs 43%; P = .0008) and OCTN2 (56.1% vs 48.4%; P = .0092) polymorphisms and homozygosity for the OCTN1/2-TC haplotype (28.4% vs 16%; P = .0042) were associated with CD versus HCs. IGR2198 homozygosity and TC homozygosity were associated with stricturing/penetrating disease at follow-up (P = .011 and P = .011, respectively) and disease progression (P = .038 and P = .049, respectively) on univariate analysis and with need for surgery on multivariate analysis (P = .016 and P = .004, respectively). In the absence of the IBD5 risk haplotype, no association of OCTN1/2 variants with CD was detected. No associations were seen with UC. CONCLUSIONS: The IBD5 locus influences susceptibility, progression, and need for surgery in CD. However, the contribution of OCTN1/2 variants is not independent of the IBD5 haplotype; a causative role for these genes remains plausible but is not yet proven. Further genetic, functional, and expression data are now required.