© Ramona Bruckner
Perianal fistulas are a severe and frequent complication in Crohn’s Disease (CD) patients, significantly affecting their quality of life. High recurrence rates, incomplete fistula healing and non-responding patients make the treatment challenging. Despite some novel insights, current knowledge about the pathogenesis of fistula formation is still limited. Fibroblasts are abundantly present in fistulas and were recently reported to regulate Th1 cell activity in Inflammatory Bowel Disease (IBD). Our hypothesis is that fibroblasts act as the key drivers of this disease complication by regulating inflammatory cell recruitment. We will investigate which pro-inflammatory cytokines and chemoattractants are produced by fistula-derived fibroblasts and how they influence recruitment of immune cells, leading to sustained inflammation. Our second hypothesis is that mesenchymal stem cells (MSCs) can normalise this fibroblast-driven pro-inflammatory environment.
Fibroblasts will be isolated from scraping material of perianal CD fistulas, non-CD-associated fistulas, the colon of IBD patients without fistulas, normal colon (obtained at surgery for colorectal cancer) and abdominal skin. Gene expression profiling via mRNA sequencing of cultured fistula-derived fibroblasts will be performed. The characterisation will be complemented by flow cytometry analysis. The interaction of fibroblasts with immune cell subsets and MSCs will be studied in co-culture experiments.
The project was started in March 2019. Currently mRNA sequencing is being performed and we expect to have the results within the next 2 months. This will allow us to perform functional follow-up experiments in vitro to validate the most interesting hits on mRNA and protein level using flow cytometry analysis. In parallel, co-culture experiments with immune cells will be carried out. In the last phase of this project we will compare fistula-derived fibroblasts and MSCs with respect to immunoregulation based on the obtained findings.
|ECCO'19 Fellowship Awardees