Genetic Evidence Supporting the Association of Protease and Protease Inhibitor Genes with Inflammatory Bowel Disease: A Systematic Review

As part of the European research consortium IBDase, we addressed the role of proteases and protease inhibitors (P/PIs) in inflammatory bowel disease (IBD), characterized by chronic mucosal inflammation of the gastrointestinal tract, which affects 2.2 million people in Europe and 1.4 million people in North America. We systematically reviewed all published genetic studies on populations of European ancestry (67 studies on Crohn's disease [CD] and 37 studies on ulcerative colitis [UC]) to identify critical genomic regions associated with IBD. We developed a computer algorithm to map the 807 P/PI genes with exact genomic locations listed in the MEROPS database of peptidases onto these critical regions and to rank P/PI genes according to the accumulated evidence for their association with CD and UC. 82 P/PI genes (75 coding for proteases and 7 coding for protease inhibitors) were retained for CD based on the accumulated evidence. The cylindromatosis/turban tumor syndrome gene (CYLD) on chromosome 16 ranked highest, followed by acylaminoacyl-peptidase (APEH), dystroglycan (DAG1), macrophage-stimulating protein (MST1) and ubiquitin-specific peptidase 4 (USP4), all located on chromosome 3. For UC, 18 P/PI genes were retained (14 proteases and 4protease inhibitors), with a considerably lower amount of accumulated evidence. The ranking of P/PI genes as established in this systematic review is currently used to guide validation studies of candidate P/PI genes, and their functional characterization in interdisciplinary mechanistic studies in vitro and in vivo as part of IBDase. The approach used here overcomes some of the problems encountered when subjectively selecting genes for further evaluation and could be applied to any complex disease and gene family

Genetic Variants of Wnt Transcription Factor TCF-4 (TCF7L2) Putative Promoter Region Are Associated with Small Intestinal Crohn's Disease

Reduced expression of Paneth cell antimicrobial α-defensins, human defensin (HD)-5 and -6, characterizes Crohn's disease (CD) of the ileum. TCF-4 (also named TCF7L2), a Wnt signalling pathway transcription factor, orchestrates Paneth cell differentiation, directly regulates the expression of HD-5 and -6, and was previously associated with the decrease of these antimicrobial peptides in a subset of ileal CD. To investigate a potential genetic association of TCF-4 with ileal CD, we sequenced 2.1 kb of the 5′ flanking region of TCF-4 in a small group of ileal CD patients and controls (n = 10 each). We identified eight single nucleotide polymorphisms (SNPs), of which three (rs3814570, rs10885394, rs10885395) were in linkage disequilibrium and found more frequently in patients; one (rs3814570) was thereby located in a predicted regulatory region. We carried out high-throughput analysis of this SNP in three cohorts of inflammatory bowel disease (IBD) patients and controls. Overall 1399 healthy individuals, 785 ulcerative colitis (UC) patients, 225 CD patients with colonic disease only and 784 CD patients with ileal involvement were used to determine frequency distributions. We found an association of rs3814570 with ileal CD but neither with colonic CD or UC, in a combined analysis (allele positivity: OR 1.27, 95% CI 1.07 to 1.52, p = 0.00737), which was the strongest in ileal CD patients with stricturing behaviour (allele frequency: OR 1.32, 95% CI 1.08 to1.62, p = 0.00686) or an additional involvement of the upper GIT (allele frequency: OR 1.38, 95% CI 1.03 to1.84, p = 0.02882). The newly identified genetic association of TCF-4 with ileal CD provides evidence that the decrease in Paneth cell α-defensins is a primary factor in disease pathogenesis

Genetic Variation in the Familial Mediterranean Fever Gene (MEFV) and Risk for Crohn's Disease and Ulcerative Colitis

BACKGROUND AND AIMS: The familial Mediterranean fever (FMF) gene (MEFV) encodes pyrin, a major regulator of the inflammasome platform controlling caspase-1 activation and IL-1beta processing. Pyrin has been shown to interact with the gene product of NLRP3, NALP3/cryopyrin, also an important active member of the inflammasome. The NLRP3 region was recently reported to be associated with Crohn's disease (CD) susceptibility. We therefore sought to evaluate MEFV as an inflammatory bowel disease (IBD) susceptibility gene. METHODOLOGY AND RESULTS: MEFV colonic mucosal gene expression was significantly increased in experimental colitis mice models (TNBS p<0.0003; DSS p<0.006), in biopsies from CD (p<0.02) and severe ulcerative colitis (UC) patients (p<0.008). Comprehensive genetic screening of the MEFV region in the Belgian exploratory sample set (440 CD trios, 137 UC trios, 239 CD cases, 96 UC cases, and 107 healthy controls) identified SNPs located in the MEFV 5' haplotype block that were significantly associated with UC (rs224217; p = 0.003; A allele frequency: 56% cases, 45% controls), while no CD associations were observed. Sequencing and subsequent genotyping of variants located in this associated haplotype block identified three synonymous variants (D102D/rs224225, G138G/rs224224, A165A/rs224223) and one non-synonymous variant (R202Q/rs224222) located in MEFV exon 2 that were significantly associated with UC (rs224222: p = 0.0005; A allele frequency: 32% in cases, 23% in controls). No consistent associations were observed in additional Canadian (256 CD trios, 91 UC trios) and Scottish (495 UC, 370 controls) sample sets. We note that rs224222 showed marginal association (p = 0.012; G allele frequency: 82% in cases, 70% in controls) in the Canadian sample, but with a different risk allele. None of the NLRP3 common variants were associated with UC in the Belgian-Canadian UC samples and no significant interactions were observed between NLRP3 and MEFV that could explain the observed flip-flop of the rs224222 risk allele. CONCLUSION: The differences in association levels observed between the sample sets may be a consequence of distinct founder effects or of the relative small sample size of the cohorts evaluated in this study. However, the results suggest that common variants in the MEFV region do not contribute to CD and UC susceptibility.Journal ArticleResearch Support, N.I.H. ExtramuralResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Developing a Standard Set of Patient-Centred Outcomes for inflammatory Bowel Disease-an international, cross-disciplinary consensus

Background and Aims: Success in delivering value-based healthcare involves measuring outcomes that matter most to patients. Our aim was to develop a minimum Standard Set of patient-centred outcome measures for inflammatory bowel disease [IBD], for use in different healthcare settings. Methods: An international working group [n = 25] representing patients, patient associations, gastroenterologists, surgeons, specialist nurses, IBD registries and patient-reported outcome measure [PROM] methodologists participated in a series of teleconferences incorporating a modified Delphi process. Systematic review of existing literature, registry data, patient focus groups and open review periods were used to reach consensus on a minimum set of standard outcome measures and risk adjustment variables. Similar methodology has been used in 21 other disease areas [www.ichom.org]. Results: A minimum Standard Set of outcomes was developed for patients [aged =16] with IBD. Outcome domains included survival and disease control [survival, disease activity/remission, colorectal cancer, anaem

Large-scale sequencing identifies multiple genes and rare variants associated with Crohn’s disease susceptibility

peer reviewe

Janus Kinase Antagonists and Other Novel Small Molecules for the Treatment of Crohn's Disease

There is an ongoing, unmet need for effective therapies for Crohn's disease. Treatments for Crohn's disease continue to evolve from the traditional biologics to novel small molecules, with targeted mechanisms directed toward pathways that are dysregulated in Crohn's disease. There are multiple emerging mechanisms of action, including Janus kinase inhibition, Smad7 inhibition, and sphingosine-1-phosphate receptor modulators, that are administered as oral medications, and small molecules represent the next generation of therapies for Crohn's disease

Dose de-escalation to adalimumab 40 mg every 3 weeks in patients with Crohn's disease - a nested case-control study

BACKGROUND: Data on dose de-escalation in patients with Crohn's disease (CD) are limited. AIM: To evaluate outcomes of dose de-escalation from adalimumab (ADM) every other week (EOW) to every three weeks (ETW). METHODS: We selected patients with CD receiving maintenance therapy with ADM 40 mg ETW with serum levels (SL) available before and after dose de-escalation. Sex- and age-matched controls continuing ADM 40 mg EOW were identified. Patient reported outcome, C-reactive protein (CRP) and serum albumin were collected. RESULTS: Out of 898 patients, we identified 40 (11 male, median 37 years) who de-escalated to ADM 40 mg ETW for ADM-related adverse events (AE, n = 1), ADM SL >7 μg/mL (n = 8), or both (n = 31). Compared to controls, ADM SL dropped significantly within 4 months, without associated clinical or biochemical changes. In 53% of patients, dose de-escalation was associated with disappearance of AE (8/16 skin manifestation, 3/6 arthralgia, 5/7 frequent infectious episodes). During a median follow-up of 24 months, 65% of patients maintained clinical response, but 35% needed dose escalation back to ADM 40 mg EOW because of clinical relapse (n = 8), ADM SL <4 μg/mL (n = 2), or both (n = 4). CRP <3.5 mg/L at dose de-escalation was independently associated with dose escalation-free survival [odds ratio 6.28 (95% CI 1.83-21.59), P = 0.004]. We could not define a minimal ADM SL to consider or maintain dose de-escalation. CONCLUSIONS: Overall, 65% of patients who de-escalated to adalimumab 40 mg every 3 weeks remained in clinical remission for a median of 24 months. In 53% of patients, adalimumab-related adverse events disappeared after dose de-escalation. Regardless of adalimumab SL, disease remission should be assessed objectively prior to dose de-escalation.status: publishe

Impact of Infliximab on weight regulation and lipid metabolism: Immuno-neutralization of TNF induces leptinemia in Crohn’s Disease

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