MicroRNAs im Stuhl als Biomarker für chronisch entzündliche Darmerkrankungen

MicroRNAs in faeces as Biomarkers for Inflammatory Bowel DiseasesIrene Raphaela Theresa BreunigIn a pilot study we compared and optimized different methods of RNA extraction from stool samples in order to obtain high RNA purity. The best results were obtained by RNA purification using Norgen columns after phenol-chloroform extraction. We then performed the first miRNA screen in faeces of IBD patients and controls using Nanostring technology. Hereby we found specific miRNAs with higher and lower presence in faeces of patients. They were subsequently measured by qPCR in a larger cohort with different subgroups of IBD patients, CDI patients and controls.miR-223 and miR1246 were both highly present in faeces. In ulcerative colitis they presented significantly higher levels than in controls and correlated with the well-established markers of inflammation CRP and Calprotectin, as well as with clinical IBD activity scores. miR-1246 was also higher in CDI patients and hence seems to be an unspecific marker of colon inflammation. However, miR-223 was not elevated in this group despite important level of inflammation and therefore has a certain specificity for UC. This will need to be confirmed in further studies.miRNA profiles of IBD patients had an important interindividual variability, as well as disease behaviour and response to medication are different between individuals and difficult to predict. In a follow-up study miRNA profiles will be investigated before treatment onset in order to assess if distinct miRNA patterns can be used as indicators for treatment response