Miquel A. Gassull

Bio: Miquel A. Gassull is an academic researcher from Autonomous University of Barcelona. The author has contributed to research in topics: Inflammatory bowel disease & Ulcerative colitis. The author has an hindex of 56, co-authored 195 publications receiving 17073 citations. Previous affiliations of Miquel A. Gassull include University of Barcelona & Bellvitge University Hospital.

Association of NOD2 leucine-rich repeat variants with susceptibility to Crohn's disease

Abstract: Crohn's disease and ulcerative colitis, the two main types of chronic inflammatory bowel disease, are multifactorial conditions of unknown aetiology A susceptibility locus for Crohn's disease has been mapped to chromosome 16 Here we have used a positional-cloning strategy, based on linkage analysis followed by linkage disequilibrium mapping, to identify three independent associations for Crohn's disease: a frameshift variant and two missense variants of NOD2, encoding a member of the Apaf-1/Ced-4 superfamily of apoptosis regulators that is expressed in monocytes These NOD2 variants alter the structure of either the leucine-rich repeat domain of the protein or the adjacent region NOD2 activates nuclear factor NF-kB; this activating function is regulated by the carboxy-terminal leucine-rich repeat domain, which has an inhibitory role and also acts as an intracellular receptor for components of microbial pathogens These observations suggest that the NOD2 gene product confers susceptibility to Crohn's disease by altering the recognition of these components and/or by over-activating NF-kB in monocytes, thus documenting a molecular model for the pathogenic mechanism of Crohn's disease that can now be further investigated

The second European evidence-based Consensus on the diagnosis and management of Crohn's disease: Current management

Abstract: This paper is the second in a series of three publications relating to the European evidence-based consensus on the diagnosis and management of Crohn's disease and concerns the management of active disease, maintenance of medically induced remission and surgery. The aims and methods of the ECCO Consensus, as well as sections on diagnosis and classification are covered in the first paper [van Assche et al. JCC 2009a]. The final paper covers post-operative recurrence, fistulating disease, the management of paediatric and adolescent IBD, pregnancy, psychosomatics, extraintestinal manifestations and complementary or alternative therapy for Crohn's disease [Van Assche et al JCC 2009b]. #### Principal changes with respect to the 2006 ECCO guidelines The early use of azathioprine/mercaptopurine or methotrexate in combination with steroids is an appropriate option in moderately active localised ileocaecal CD. Anti-TNF therapy should be considered as an alternative for patients with objective evidence of active disease who have previously been steroid-refractory, steroid-dependent, or steroid-intolerant (based on Statement 5B). For those patients with severely active localised ileocaecal Crohn's disease and objective evidence of active disease who have relapsed, anti-TNF therapy with or without an immunomodulator is an appropriate option [EL1a, RG B for infliximab]. For some patients who have infrequently relapsing disease, restarting steroids with an immunomodulator may be appropriate (based on Statement 5C). All currently available anti-TNF therapies appear to have generally similar efficacy and adverse-event profiles for inflammatory (‘luminal’) Crohn's disease, so the choice depends on availability, route of delivery, patient preference, cost and national guidelines \[EL5, RG D\] (Statement 5I). Patients receiving azathioprine or mercaptopurine who relapse should be evaluated for adherence to therapy and have their dose optimised. Changing their maintenance therapy to methotrexate [EL1b RG B] or anti-TNF therapy [EL1a RGB] should be considered. Surgery should always be considered as an option in localised disease [EL4, …

CARD15/NOD2 mutational analysis and genotype-phenotype correlation in 612 patients with inflammatory bowel disease.

Abstract: CARD15/NOD2 encodes a protein involved in bacterial recognition by monocytes. Mutations in CARD15 have recently been found in patients with Crohn disease (CD), a chronic inflammatory condition of the digestive tract. Here, we report the mutational analyses of CARD15 in 453 patients with CD, including 166 sporadic and 287 familial cases, 159 patients with ulcerative colitis (UC), and 103 healthy control subjects. Of 67 sequence variations identified, 9 had an allele frequency >5% in patients with CD. Six of them were considered to be polymorphisms, and three (R702W, G908R, and 1007fs) were confirmed to be independently associated with susceptibility to CD. Also considered as potential disease-causing mutations (DCMs) were 27 rare additional mutations. The three main variants (R702W, G908R, and 1007fs) represented 32%, 18%, and 31%, respectively, of the total CD mutations, whereas the total of the 27 rare mutations represented 19% of DCMs. Altogether, 93% of the mutations were located in the distal third of the gene. No mutations were found to be associated with UC. In contrast, 50% of patients with CD carried at least one DCM, including 17% who had a double mutation. This observation confirmed the gene-dosage effect in CD. The patients with double-dose mutations were characterized by a younger age at onset (16.9 years vs. 19.8 years; P=.01), a more frequent stricturing phenotype (53% vs. 28%; P=.00003; odds ratio 2.92), and a less frequent colonic involvement (43% vs. 62%; P=.003; odds ratio 0.44) than were seen in those patients who had no mutation. The severity of the disease and extraintestinal manifestations were not different for any of the CARD15 genotypes. The proportion of familial and sporadic cases and the proportion of patients with smoking habits were similar in the groups of patients with CD with or without mutation. These findings provide tools for a DNA-based test of susceptibility and for genetic counseling in inflammatory bowel disease.

European evidence-based Consensus on the management of ulcerative colitis: Current management.

Abstract: ### 5.1 General The general principles for treating active ulcerative colitis are to consider the activity, distribution (proctitis, left-sided, extensive,1 and pattern of disease (relapse frequency, course of disease, response to previous medications, side-effect profile of medication, extra-intestinal manifestation), before treatment decisions are made in conjunction with the patient. #### 5.1.1 Disease activity The principal scoring systems used for clinical trials are covered in Section 5.1.2 and have been comprehensively reviewed.2 Some additional points are clinically relevant. In clinical practice it matters most to distinguish severe ulcerative colitis necessitating hospital admission from those with mild or moderate disease who can generally be treated as outpatients. The simplest, best validated and most widely used index for identifying acute severe UC remains that of Truelove & Wi_tts 3: 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). This index has been used in 20/32 studies of intensive intravenous treatment for severe UC.4 Only one additional criterion in addition to the bloody stool frequency ≥ 6/day is needed to define a severe attack.5 While these criteria have the major limitation of being unresponsive and cannot track the course of disease, they do distinguish the severe from the moderate or mild and have value in everyday practice because they are easy to use, which no other index achieves. It should be standard practice to confirm active colitis by sigmoidoscopy or proctoscopy before starting treatment. Rectal mucosal biopsy helps exclude unexpected causes of symptoms similar to active disease (such as cytomegalovirus, amoebic, or other infection, rectal mucosal prolapse, Crohn's disease, or even irritable bowel syndrome and haemorrhoidal bleeding). #### 5.1.2 Approach Patients should be encouraged to participate actively in …

Genome-wide association study of 14,000 cases of seven common diseases and 3,000 shared controls

Abstract: There is increasing evidence that genome-wide association ( GWA) studies represent a powerful approach to the identification of genes involved in common human diseases. We describe a joint GWA study ( using the Affymetrix GeneChip 500K Mapping Array Set) undertaken in the British population, which has examined similar to 2,000 individuals for each of 7 major diseases and a shared set of similar to 3,000 controls. Case-control comparisons identified 24 independent association signals at P < 5 X 10(-7): 1 in bipolar disorder, 1 in coronary artery disease, 9 in Crohn's disease, 3 in rheumatoid arthritis, 7 in type 1 diabetes and 3 in type 2 diabetes. On the basis of prior findings and replication studies thus-far completed, almost all of these signals reflect genuine susceptibility effects. We observed association at many previously identified loci, and found compelling evidence that some loci confer risk for more than one of the diseases studied. Across all diseases, we identified a large number of further signals ( including 58 loci with single-point P values between 10(-5) and 5 X 10(-7)) likely to yield additional susceptibility loci. The importance of appropriately large samples was confirmed by the modest effect sizes observed at most loci identified. This study thus represents a thorough validation of the GWA approach. It has also demonstrated that careful use of a shared control group represents a safe and effective approach to GWA analyses of multiple disease phenotypes; has generated a genome-wide genotype database for future studies of common diseases in the British population; and shown that, provided individuals with non-European ancestry are excluded, the extent of population stratification in the British population is generally modest. Our findings offer new avenues for exploring the pathophysiology of these important disorders. We anticipate that our data, results and software, which will be widely available to other investigators, will provide a powerful resource for human genetics research.

Innate Immune Recognition

Abstract: ▪ Abstract The innate immune system is a universal and ancient form of host defense against infection. Innate immune recognition relies on a limited number of germline-encoded receptors. These receptors evolved to recognize conserved products of microbial metabolism produced by microbial pathogens, but not by the host. Recognition of these molecular structures allows the immune system to distinguish infectious nonself from noninfectious self. Toll-like receptors play a major role in pathogen recognition and initiation of inflammatory and immune responses. Stimulation of Toll-like receptors by microbial products leads to the activation of signaling pathways that result in the induction of antimicrobial genes and inflammatory cytokines. In addition, stimulation of Toll-like receptors triggers dendritic cell maturation and results in the induction of costimulatory molecules and increased antigen-presenting capacity. Thus, microbial recognition by Toll-like receptors helps to direct adaptive immune responses ...

An integrated map of genetic variation from 1,092 human genomes

Abstract: By characterizing the geographic and functional spectrum of human genetic variation, the 1000 Genomes Project aims to build a resource to help to understand the genetic contribution to disease. Here we describe the genomes of 1,092 individuals from 14 populations, constructed using a combination of low-coverage whole-genome and exome sequencing. By developing methods to integrate information across several algorithms and diverse data sources, we provide a validated haplotype map of 38 million single nucleotide polymorphisms, 1.4 million short insertions and deletions, and more than 14,000 larger deletions. We show that individuals from different populations carry different profiles of rare and common variants, and that low-frequency variants show substantial geographic differentiation, which is further increased by the action of purifying selection. We show that evolutionary conservation and coding consequence are key determinants of the strength of purifying selection, that rare-variant load varies substantially across biological pathways, and that each individual contains hundreds of rare non-coding variants at conserved sites, such as motif-disrupting changes in transcription-factor-binding sites. This resource, which captures up to 98% of accessible single nucleotide polymorphisms at a frequency of 1% in related populations, enables analysis of common and low-frequency variants in individuals from diverse, including admixed, populations.

The International HapMap Project

Abstract: The goal of the International HapMap Project is to determine the common patterns of DNA sequence variation in the human genome and to make this information freely available in the public domain. An international consortium is developing a map of these patterns across the genome by determining the genotypes of one million or more sequence variants, their frequencies and the degree of association between them, in DNA samples from populations with ancestry from parts of Africa, Asia and Europe. The HapMap will allow the discovery of sequence variants that affect common disease, will facilitate development of diagnostic tools, and will enhance our ability to choose targets for therapeutic intervention.

Toll-like receptors.

Abstract: The innate immune system in drosophila and mammals senses the invasion of microorganisms using the family of Toll receptors, stimulation of which initiates a range of host defense mechanisms. In drosophila antimicrobial responses rely on two signaling pathways: the Toll pathway and the IMD pathway. In mammals there are at least 10 members of the Toll-like receptor (TLR) family that recognize specific components conserved among microorganisms. Activation of the TLRs leads not only to the induction of inflammatory responses but also to the development of antigen-specific adaptive immunity. The TLR-induced inflammatory response is dependent on a common signaling pathway that is mediated by the adaptor molecule MyD88. However, there is evidence for additional pathways that mediate TLR ligand-specific biological responses.