Embark cross-sectional study of inactive and active lesions from the ileum and colon of inflammatory bowel disease patients

Hypothesis: Gene expression differences in biopsies from patients with inflammatory bowel disease can be used to identify molecular heterogeneity within patients with active disease. Methods: Patients with a diagnosis of Crohn's disease, ulcerative colitis or normal healthy controls (with or without infectious colitis) underwent ileocolonoscopy. In healthy controls, biopsies were taken in the sigmoid colon (n=21), ascending/descending colon (n=25) and the terminal ileum (n=12). In patients with Crohn's disease, biopsies were taken in the ascending/descending colon (n=107) and terminal ileum (n=70) in uninflamed areas in all patients; in patients with mucosal lesions, additional biopsies were taken in inflamed regions of the ascending/descending colon (n=35) and terminal ileum (n=55). In ulcerative colitis patients, paired uninflamed sigmoid (n=48) and inflamed sigmoid biopsies (n=46) were taken. Biopsies were placed in RNAlater at the clinical site, frozen and shipped to Genentech, where they were disrupted using TissueLyzer beads, then RNA was isolated using RNeasy columns. RNA was hybridized to Agilent human 4x44kv1 arrays, dual channel, using universal reference. Intestinal biopsies were collected from active lesions and inactive adjacent regions in patients with either Crohn's disease or ulcerative colitis. Matched non-IBD controls with no obvious intestinal disease are included for comparison.