DOP89 Pre-treatment mucosal inflammatory and wound healing gene programmes reveal mechanisms associated with future stricturing behaviour during 5-year follow-up in paediatric Crohn’s disease
Y. Haberman Ziv1, P. Minar1, R. Karns1, P. Dexheimer1, S. Ghandikota1, S. Tegge1, D. Shapiro1, B. Shuler1, S. Venkateswaran2, T. Braun3, B. Aronow1, G. Gibson4, J. Hyams5, S. Kugathasan2, A. Jegga1, L. Denson1, CCF sponsored RISK Study
1Department of Gastroenterology, Cincinnati Children’s Hospital Medical Center and the University of Cincinnati College of Medicine, Cincinnati, USA, 2Department of Gastroenterology, Emory University, Atlanta, USA, 3Department of Gastroenterology, Sheba Medical Center, Ramat Gan, Israel, 4Institute of Technology, Georgia Institute of Technology, Atlanta, USA, 5Department of Gastroenterology, Connecticut Children’s Medical Center, Hartford, USA
Background
Stricturing complications account for substantial morbidity in Crohn’s disease (CD). We aimed to define ileal gene programmes present at diagnosis in paediatric CD associated with future stricturing behaviour (B2), and to identify potential small molecules to reverse these gene signatures.
Methods
Antimicrobial serologies and ileal gene expression (RNASeq) were assessed at diagnosis in 249 CD patients enrolled in a 5-year inception cohort study. These data were used to define genes associated with stricturing behaviour and for model testing to predict stricturing. Sirius Red immuno-histochemistry was utilised to determine the extent of collagen infiltration into the sub-cryptal space. A bioinformatics approach defined small molecules which may reverse the stricturing gene signature.
Results
Of 249 (8%) patients, 19 developed B2 behaviour during the 5-year follow-up, while 218 remained B1 inflammatory. We defined 518 genes that were differentially expressed in the ileum at diagnosis (FC≥1.5, FDR<0.05) in B1 patients who later developed B2 stricturing complications vs. those who remained B1 throughout. These were notable for baseline up-regulation of OSM implicated in anti-TNF non-response, NCF2 and CSF3R implicated in myeloid cell activation, TGFBI implicated in tissue fibrosis, and a panel of 17 collagen genes in patients who progressed to stricturing. Sirius red staining confirmed an increase in sub-cryptal type I/III collagen in B1 patients at diagnosis who progressed to B2 behaviour. Of these 518 genes, we highlighted an inflammatory OSM co-expression signature that was tightly associated with an extracellular matrix COL1A2 co-expression signature (Pearson
Conclusion
An ileal gene program for macrophage and fibroblast activation is linked to future stricturing complications in treatment naïve paediatric CD, and may inform small-molecule therapeutic approaches.