Identification of serum and tissue micro‐ RNA expression profiles in different stages of inflammatory bowel disease

Summary The altered expression of micro‐RNA (mi RNA ) has been associated with C rohn's disease ( CD ) and ulcerative colitis ( UC ). The aim of this study was to establish specific mi RNA expression patterns in the serum and mucosa of inflammatory bowel disease ( IBD ) patients ( UC and CD with colonic involvement) at different stages of the disease. Serum and biopsies from nine active CD (a CD ), nine inactive CD (i CD ), nine active UC (a UC ) and nine inactive UC (i UC ) and serum from 33 healthy subjects were collected. Up to 700 mi RNA s were evaluated by the T aq M an® human mi RNA array. The Δ C t values were obtained using the mean expression values of all expressed mi RNA s in a given sample as a normalization factor for mi RNA real‐time quantitative polymerase chain reaction data. The levels of serum mi RNA s in CD and UC patients were different to healthy subjects. Thirteen serum mi RNA s were expressed commonly in CD and UC patients. Two mi RNA s were higher and four mi RNA s were lower in the serum of a CD than i CD . No serum mi RNA was regulated exclusively in a UC compared with i UC patients. Four mi RNA s were higher and three mi RNA s were lower in the mucosa of a CD than i CD . Two mi RNA s were higher and three mi RNA s were lower in the mucosa of a UC than i UC . No serum mi RNA s coincided with tissue mi RNA s in a CD and a UC patients. Our results suggest the existence of specific mi RNA expression patterns associated with IBD and their different stages and support the utility of mi RNA as possible biomarkers. This pilot study needs to be validated in a large prospective cohort.