Faecal micro-RNAs in inflammatory bowel diseases.

Abstract

BACKGROUND AND AIMS\nFaecal biomarkers are used as indicators of disease activity in inflammatory bowel diseases (IBD), which include Crohn s disease (CD) and ulcerative colitis (UC). Micro-RNA (miRNA) are small non-coding RNAs detectable in extracellular fluids that can be used as clinical biomarkers. The aim of this study was to determine if the faecal miRNAs composition is altered in IBD.\n\n\nMETHODS\nMore than 800 different human faecal miRNAs were measured in stool samples from control individuals and patients with active CD using the Nanostring technology. Selected miRNAs were quantified by RT-qPCR in faeces, serum and intestinal tissue of controls (n = 23) and patients with inactive or active CD (n = 22, n = 22) or UC (n = 11, n = 24) as well as patients with Clostridium difficile infection (CDI, n = 8).\n\n\nRESULTS\n150 miRNAs were significantly detected in faeces from controls and patients, and multivariate analyses showed that CD patients with high disease activities had a distinct miRNA profile and that miR-223 and miR-1246 were distinct from other faecal miRNAs. In a larger cohort, active UC patients displayed significantly higher levels of miR-223 and miR-1246 than controls while patients with CDI had higher levels of faecal miR-1246 but not miR-223. No differences were noted in serum samples.\n\n\nCONCLUSIONS\nTo our knowledge, this is the first faecal miRNA comprehensive screen performed in IBD. Further investigation will aim at confirming these findings in a bigger cohort and at understanding the biological function and cellular sources of faecal miRNAs.