Characterization of candidate genes in inflammatory bowel disease-associated risk loci.

GWAS have linked SNPs to risk of inflammatory bowel disease (IBD), but a systematic characterization of disease-associated genes has been lacking. Prior studies utilized microarrays that did not capture many genes encoded within risk loci or defined expression quantitative trait loci (eQTLs) using peripheral blood, which is not the target tissue in IBD. To address these gaps, we sought to characterize the expression of IBD-associated risk genes in disease-relevant tissues and in the setting of active IBD.

Mechanisms of Pediatric Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD), including Crohn disease and ulcerative colitis, is characterized by chronic intestinal inflammation due to a complex interaction of genetic determinants, disruption of mucosal barriers, aberrant inflammatory signals, loss of tolerance, and environmental triggers. Importantly, the incidence of pediatric IBD is rising, particularly in children younger than 10 years. In this review, we discuss the clinical presentation of these patients and highlight environmental exposures that may affect disease risk, particularly among people with a background genetic risk.

Diagnostic and Therapeutic Yield of Endoscopy in Patients with Elevated INR and Gastrointestinal Bleeding.

Background: Gastrointestinal bleeding is a well-known risk of systemic anticoagulation. However, bleeding in the setting of supratherapeutic anticoagulation may have a milder natural history than unprovoked bleeding. It is a common clinical gestalt that endoscopy is common, but bleeding source identification or intervention is uncommon, yet few data exist to inform this clinical impression.

Body Mass Index, Genetic Susceptibility, and Risk of Complications Among Individuals with Crohn's Disease.

Background: Obesity is associated with systemic and intestine-specific inflammation and alterations in gut microbiota, which in turn impact mucosal immunity. Nonetheless, a specific role of obesity and its interaction with genetics in the progression of Crohn's disease (CD) is unclear.

Methods: We conducted a cross-sectional study of patients with CD enrolled in Prospective Registry in Inflammatory Bowel Disease Study at Massachusetts General Hospital (PRISM).

Atg16L1 T300A variant decreases selective autophagy resulting in altered cytokine signaling and decreased antibacterial defense.

A coding polymorphism (Thr300Ala) in the essential autophagy gene, autophagy related 16-like 1 (ATG16L1), confers increased risk for the development of Crohn disease, although the mechanisms by which single disease-associated polymorphisms contribute to pathogenesis have been difficult to dissect given that environmental factors likely influence disease initiation in these patients. Here we introduce a knock-in mouse model expressing the Atg16L1 T300A variant. Consistent with the human polymorphism, T300A knock-in mice do not develop spontaneous intestinal inflammation, but exhibit morphological defects in Paneth and goblet cells.

Selective modulation of autophagy, innate immunity, and adaptive immunity by small molecules.

Autophagy is an evolutionarily conserved catabolic process that directs cytoplasmic proteins, organelles and microbes to lysosomes for degradation. Autophagy acts at the intersection of pathways involved in cellular stress, host defense, and modulation of inflammatory and immune responses; however, the details of how the autophagy network intersects with these processes remain largely undefined. Given the role of autophagy in several human diseases, it is important to determine the extent to which modulators of autophagy also modify inflammatory or immune pathways and whether it is possible to modulate a subset of these pathways selectively.

Atg16l1 is required for autophagy in intestinal epithelial cells and protection of mice from Salmonella infection.

Background & Aims: Intestinal epithelial cells aid in mucosal defense by providing a physical barrier against entry of pathogenic bacteria and secreting antimicrobial peptides (AMPs). Autophagy is an important component of immune homeostasis. However, little is known about its role in specific cell types during bacterial infection in vivo.

The microbiota and inflammatory bowel disease: insights from animal models.

Inflammatory bowel disease (IBD) is thought to result from a dysregulated immune response to intestinal microbial flora in individuals with genetic predisposition(s). Genome-wide association studies (GWAS) in human IBD have identified more than 150 associated loci, some of which are key players in innate immunity and bacterial handling, reflecting the importance of the microbiota in disease pathogenesis. In fact, the presence of a microbial flora is not only crucial to the development of a normal murine immune system but also critical for the development of disease in the majority of animal models of IBD.

The Mayo Dysphagia Questionnaire-30: documentation of reliability and validity of a tool for interventional trials in adults with esophageal disease.

The aim of this study was to develop the Mayo Dysphagia Questionnaire-30 Day (MDQ-30), a tool to measure esophageal dysphagia, by adapting items from validated instruments for use in clinical trials, and assess its feasibility, reproducibility, and concurrent validity. Outpatients referred to endoscopy for dysphagia or seen in a specialty clinic were recruited. Feasibility testing was done to identify problematic items.

Diagnostic ionizing radiation exposure in a population-based cohort of patients with inflammatory bowel disease.

Objective: For diagnosis, assessing disease activity, complications and extraintestinal manifestations, and monitoring response to therapy, patients with inflammatory bowel disease undergo many radiological studies employing ionizing radiation. However, the extent of radiation exposure in these patients is unknown.

Methods: A population-based inception cohort of 215 patients with inflammatory bowel disease from Olmsted County, Minnesota, diagnosed between 1990 and 2001, was identified.