Miquel Sans

Genome-wide meta-analysis increases to 71 the number of confirmed Crohn's disease susceptibility loci

We undertook a meta-analysis of six Crohns disease genome-wide association studies (GWAS) comprising 6,333 affected individuals (cases) and 15,056 controls and followed up the top association signals in 15,694 cases, 14,026 controls and 414 parent-offspring trios. We identified 30 new susceptibility loci meeting genome-wide significance (P < 5 × 10−8). A series of in silico analyses highlighted particular genes within these loci and, together with manual curation, implicated functionally interesting candidate genes including SMAD3, ERAP2, IL10, IL2RA, TYK2, FUT2, DNMT3A, DENND1B, BACH2 and TAGAP. Combined with previously confirmed loci, these results identify 71 distinct loci with genome-wide significant evidence for association with Crohns disease.

Second European evidence-based consensus on the diagnosis and management of ulcerative colitis Part 2: Current management

### 5.1 General When deciding the appropriate treatment strategy for active ulcerative colitis one should consider the activity, distribution (proctitis, left-sided, extensive1), and pattern of disease. The disease pattern includes relapse frequency, course of disease, response to previous medications, side-effect profile of medication and extra-intestinal manifestations. The age at onset and disease duration may also be important factors. #### 5.1.1 Disease activity The principal disease activity scoring systems used in clinical trials are covered in Section 1.2 and have been comprehensively reviewed.2 However there are some practical points that are relevant for routine clinical use. For example, it is most important to distinguish patients with severe ulcerative colitis necessitating hospital admission from those with mild or moderately active disease who can generally be managed as outpatients. The simplest, best validated and most widely used index for identifying severe UC remains that of Truelove and Witts3: any patient who has a bloody stool frequency ≥ 6/day and a tachycardia (> 90 bpm), or temperature > 37.8 °C, or anaemia (haemoglobin 30 mm/h) has severe ulcerative colitis (Table 1.3). Only one additional criterion in addition to the bloody stool frequency ≥ 6/day is needed to define a severe attack.4,5 It should be standard practice to confirm the presence of active colitis by sigmoidoscopy before starting treatment. Flexible sigmoidoscopy and biopsy may exclude unexpected causes of symptoms that mimic active disease such as cytomegalovirus colitis, rectal mucosal prolapse, Crohns disease, malignancy, or even irritable bowel syndrome and haemorrhoidal bleeding. There may be a significant overlap between other diseases that mimic ulcerative colitis and the broad spectrum of UC damage.6,7 In addition, all patients with active disease require stool cultures with Clostridium difficile toxin assay to exclude enteric infection. Patients with an appropriate …

3rd European Evidence-based Consensus on the Diagnosis and Management of Crohn’s Disease 2016: Part 1: Diagnosis and Medical Management

This paper is the first in a series of two publications relating to the European Crohn’s and Colitis Organisation [ECCO] evidence-based consensus on the diagnosis and management of Crohn’s disease and concerns the methodology of the consensus process, and the classification, diagnosis and medical management of active and quiescent Crohn’s disease. Surgical management as well as special situations including management of perianal Crohn’s disease of this ECCO Consensus are covered in a subsequent second paper [Gionchetti et al JCC 2016].

VEGF-A links angiogenesis and inflammation in inflammatory bowel disease pathogenesis.

BACKGROUND & AIMS Vascular endothelial growth factor A (VEGF-A) mediates angiogenesis and might also have a role in inflammation and immunity. We examined whether VEGF-A signaling has a role in inflammatory bowel disease (IBD). METHODS Expression levels of VEGF-A, and its receptors VEGFR-1 and VEGFR-2, were examined in samples from patients with IBD and compared with those of controls. The capacity of VEGF-A to induce angiogenesis was tested in human intestinal microvascular endothelial cells using cell-migration and matrigel tubule-formation assays. Levels of vascular cellular adhesion molecule-1 and intercellular adhesion molecule were measured by flow cytometry to determine induction of inflammation; neutrophil adhesion was also assayed. Expression patterns were determined in tissues from mice with dextran sulfate sodium (DSS)-induced colitis; the effects of VEGF-A overexpression and blockade were assessed in these mice by adenoviral transfer of VEGF-A and soluble VEGFR-1. Intestinal angiogenesis was measured by quantitative CD31 staining and leukocyte adhesion in vivo by intravital microscopy. RESULTS Levels of VEGF-A and VEGFR-2 increased in samples from patients with IBD and colitic mice. VEGF-A induced angiogenesis of human intestinal microvascular endothelial cells in vitro as well as an inflammatory phenotype and adherence of neutrophils to intestinal endothelium. Overexpression of VEGF-A in mice with DSS-induced colitis worsened their condition, whereas overexpression of soluble VEGFR-1 had the opposite effect. Furthermore, overexpression of VEGF-A increased mucosal angiogenesis and stimulated leukocyte adhesion in vivo. CONCLUSIONS VEGF-A appears to be a novel mediator of IBD by promoting intestinal angiogenesis and inflammation. Agents that block VEGF-A signaling might reduce intestinal inflammation in patients with IBD.

VCAM-1 and ICAM-1 mediate leukocyte-endothelial cell adhesion in rat experimental colitis

BACKGROUND & AIMS The molecular mechanisms responsible for leukocyte recruitment in experimental colitis are poorly understood. The aims of this study were to measure expression of endothelial intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) and to determine their role in leukocyte recruitment in experimental colitis. METHODS Rats with trinitrobenzene sulfonic acid (TNBS)-induced colitis and control rats were studied 1, 7, or 21 days after treatment. ICAM-1 and VCAM-1 expressions were measured by the double radiolabeled antibody technique. Leukocyte-endothelial cell interactions were determined in colonic venules by fluorescence intravital microscopy. Therapeutic effects of treatment with anti-VCAM-1 antibodies were also assessed. RESULTS Colonic endothelial ICAM-1 was constitutively expressed and did not increase in colitic animals. In contrast, constitutive expression of VCAM-1 was low but markedly increased (6-fold) 1 and 7 days after induction of colitis. Increased colonic expression of VCAM-1 paralleled macroscopic damage score, myeloperoxidase activity, and increased leukocyte adhesion in colonic venules. The latter was significantly decreased by immunoneutralization of ICAM-1 and completely abrogated by immunoneutralization of VCAM-1. Long-term administration of anti-VCAM-1 antibody resulted in significant attenuation of colitis. CONCLUSIONS Induction of colitis in rats by TNBS is followed by up-regulation of endothelial VCAM-1. VCAM-1 and constitutive ICAM-1 are major determinants of leukocyte recruitment to the inflamed intestine.

VCAM-1, but not ICAM-1 or MAdCAM-1, immunoblockade ameliorates DSS-induced colitis in mice.

Adhesion molecule immunoneutralization is envisioned as a promising therapy for inflammatory bowel disease, but the relative value of selective blockade of different adhesion molecules has not been established. The aims of this study were to measure expression and functional relevance of endothelial intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in leukocyte recruitment in experimental colitis and to compare the therapeutic effectiveness of their selective blockade. For this purpose, cell adhesion molecule expression was measured by the dual radiolabeled antibody technique in mice with dextran sulfate sodium-induced colitis and controls. Leukocyte-endothelial cell interactions were determined in colonic venules by fluorescence intravital microscopy. Therapeutic effects of chronic treatment with anti-ICAM-1, anti-VCAM-1, or anti-MAdCAM-1 antibodies were also assessed. Whereas colonic endothelial ICAM-1 was constitutively expressed and had a mild up-regulation in colitic animals, constitutive expression of VCAM-1 and MAdCAM-1 was low, but markedly increased after induction of colitis. Leukocyte adhesion was abrogated by immunoneutralization of VCAM-1 or MAdCAM-1 but not by treatment with an anti-ICAM-1 antibody. Chronic administration of anti-VCAM-1 antibody, but not anti-ICAM-1 or anti-MAdCAM-1, resulted in significant attenuation of colitis in terms of disease activity index, colon length, ratio of colon weight to length, and myeloperoxidase activity. In conclusion, VCAM-1 plays a central role in leukocyte recruitment in colitis and blockade of this adhesion molecule has higher therapeutic effect than immunoneutralization of ICAM-1 or MAdCAM-1 in this experimental model.

Early Azathioprine Therapy Is No More Effective Than Placebo for Newly Diagnosed Crohn's Disease

BACKGROUND & AIMS A small placebo-controlled trial reported the efficacy of mercaptopurine therapy for children newly diagnosed with Crohns disease, yet little is known about the efficacy of early thiopurine therapy in adults. METHODS We performed a prospective double-blind trial of adult patients with a recent (<8 weeks) diagnosis of Crohns disease. Patients were randomly assigned to groups given azathioprine (2.5 mg · kg(-1) · day(-1), n = 68) or placebo (n = 63) at 31 hospitals from February 2006 to September 2009. Corticosteroids but no other concomitant medications were allowed for control of disease activity. The primary measure of efficacy was sustained corticosteroid-free remission. RESULTS After 76 weeks of treatment, 30 patients treated with azathioprine (44.1%) and 23 given placebo (36.5%) were in sustained corticosteroid-free remission (difference of 7.6%; 95% confidence interval, -9.2 to 24.4%; P = .48). The rates of relapse (defined as Crohns Disease Activity Index score >175) and corticosteroid requirements were similar between groups. A post hoc analysis of relapse, defined as a Crohns Disease Activity Index score >220, showed lower relapse rates in the azathioprine group than in the placebo group (11.8% vs 30.2%; P = .01). Serious adverse events occurred in 14 patients in the azathioprine group (20.6%) and 7 in the placebo group (11.1%) (P = .16). A larger percentage of patients in the azathioprine group had adverse events that led to study drug discontinuation (20.6%) than in the placebo group (6.35%) (P = .02). CONCLUSIONS In a study of adults with Crohns disease, early azathioprine therapy was no more effective than placebo to achieve sustained corticosteroid-free remission but was more effective in preventing moderate to severe relapse in a post hoc analysis. EudraCT 2005-001186-34.

Crohn's Disease Patients Carrying Nod2/CARD15 Gene Variants Have an Increased and Early Need for First Surgery due to Stricturing Disease and Higher Rate of Surgical Recurrence

Objective:To study the predictive value of Nod2/CARD15 gene variants along with disease phenotypic characteristics for requirement of initial surgery and for surgical recurrence in Crohns disease (CD). Summary Background Data:Nod2/CARD15 gene variants play an important role in the susceptibility to CD. Studies of genotype-phenotype relationship suggest that these variants are associated with development of intestinal strictures. Preliminary reports analyzing the association between these variants and need for surgery have produced inconsistent results. Methods:A total of 170 CD patients were included prospectively in the study and followed up regularly for a mean of 7.4 ± 6.1 years. Clinical characteristics of CD, time and indication for surgery, and recurrence were registered. Nod2/CARD15 gene variants were determined by DNA sequencing analysis. Results:Surgery for stricturing disease was significantly more frequent in patients with Nod2/CARD15 variants in the univariate analysis (odds ratio [OR], 3.63; 95% confidence interval [CI], 1.42–9.27), and it was required at an earlier time (P = 0.004). Only Nod2/CARD15 variants (OR, 3.58; 95% CI, 1.21–10.5) and stricturing phenotype at diagnosis of CD (OR, 9.34; 95% CI, 2.56–33.3) were independent predictive factors of initial surgery for stricturing lesions in the multivariate analysis. Among 70 patients that required surgery, postoperative recurrence was also more frequent in patients with Nod2/CARD15 variants in the univariate and multivariate analysis (OR, 3.29; 95% CI, 1.13–9.56), and reoperation was needed at an earlier time (P = 0.03). Conclusion:Nod2/CARD15 variants are associated with early initial surgery due to stenosis and with surgical recurrence in Crohns disease. Patients with these variants could benefit from preventive and/or early therapeutic strategies.

Cutting Edge: T Cells Trigger CD40-Dependent Platelet Activation and Granular RANTES Release: A Novel Pathway for Immune Response Amplification

Platelets, in addition to exerting hemostatic activity, contribute to immunity and inflammation. The recent report that platelets express CD40 led us to hypothesize that CD40 ligand (CD40L)-positive T cells could bind to platelets, cause their activation, and trigger granular RANTES release, creating a T cell recruitment feedback loop. Platelets were cocultured with resting or activated autologous T cells and their activation was assessed by P-selectin expression. RANTES binding to endothelial cells was assessed by confocal microscopy, and its biological activity was demonstrated by a T cell adhesion assay. CD40L-positive T cells induced platelet activation through a contact-mediated, CD40-dependent pathway resulting in RANTES release, which bound to endothelial cells and mediated T cell recruitment. Soluble CD40L induced the same events via p38, but not extracellular signal-regulated kinase, phosphorylation. These results show the existence of a novel platelet-dependent pathway of immune response amplification which brings these nonimmune cells close to the level of pathogenic relevance traditionally attributed to classical immune cells.

Genetic factors conferring an increased susceptibility to develop Crohn's disease also influence disease phenotype: results from the IBDchip European Project

Objective Through genome-wide association scans and meta-analyses thereof, over 70 genetic loci (Crohns disease (CD) single nucleotide polymorphisms (SNPs)) are significantly associated with CD. We aimed to investigate the influence of CD-SNPs and basic patient characteristics on CD clinical course, and develop statistical models to predict CD clinical course. Design This retrospective study included 1528 patients with CD with more than 10 years of follow-up from eight European referral hospitals. CD outcomes of interest were ileal (L1), colonic (L2) and ileocolonic disease location (L3); stenosing (B2) or penetrating behaviour (B3); perianal disease; extraintestinal manifestations; and bowel resection. A complicated disease course was defined as stenosing or penetrating behaviour, perianal disease and/or bowel resection. Association between CD-SNPs or patient characteristics and specified outcomes was studied. Results Several CD-SNPs and clinical characteristics were statistically associated with outcomes of interest. The NOD2 gene was the most important genetic factor, being an independent predictive factor for ileal location (p=2.02×10-06, OR=1.90), stenosing (p=3.16×10-06, OR=1.82) and penetrating (p=1.26×10-02, OR=1.25) CD behaviours, and need for surgery (p=2.28×e-05, OR=1.73), and as such was also the strongest factor associated with a complicated disease course (p=6.86×10-06, OR=2.96). Immunomodulator (azathioprine/6-mercaptopurine and methotrexate) use within 3 years after diagnosis led to a reduction in bowel stenoses (p=1.48×10-06, OR=0.35) and surgical rate (p=1.71×10-07, OR=0.34). Association between each outcome and genetic scores, created using significant SNPs in the univariate analysis, revealed large differences in the probability of developing fistulising disease (IL23R, LOC441108, PRDM1, NOD2; p=9.64e-4, HR=1.43), need for surgery (IRGM, TNFSF15, C13ORF31, NOD2; p=7.12×10-03, HR=1.35), and stenosing disease (NOD2, JAK2, ATG16L1; p=3.01×10-02, HR=1.29) among patients with low and high score. Conclusions This large multicentre cohort study has found several genetic and clinical factors influencing the clinical course of CD. NOD2 and early immunomodulator use are the clinically most meaningful predictors for its clinical course.