Supplementary file 1_A model for Crohn’s disease post-ileal resection fibrosis development using human ileal enteroids and myofibroblasts.docx

BackgroundFibrosis and inflammation frequently emerge soon after ileal resection for strictures in Crohn’s disease (CD).
ObjectiveThis study examined the profibrotic and proinflammatory effects of conditioned media from TNF and IFN-γ (T+I)-exposed healthy and inactive CD ileal enteroids (CDiE) on subepithelial myofibroblasts (SEMF), modeling early post-ileal resection conditions in CD.
MethodsIleal enteroids from healthy subjects (HE) and inactive CD patients (CDiE) were exposed to T+I for 6 hours, followed by an 18-hour conditioning period. Conditioned media were collected and applied to human intestinal myofibroblasts (HIMF) from healthy and inactive CD ileum for 24 hours to assess proinflammatory and profibrotic gene expression.
ResultsT+I exposure induced epithelial damage and cell death in CDiE, while reducing proliferation and decreasing occludin and F-actin expression in both HE and CDiE. TEER (transepithelial electrical resistance) declined in CDiE but remained stable in HE. Conditioned media from T+I-exposed enteroids altered HIMF-HC (healthy control) and HIMF-CD mRNA expression, upregulating proinflammatory genes (IL1B, IL6, MCP1, and IKBA) while downregulating profibrotic genes (COL1A1, ACTA2, TGFB, and SRF).
ConclusionCytokine-exposed HE- and CDiE-derived conditioned media promoted inflammation while suppressing fibrosis-associated gene expression in subepithelial myofibroblasts. Our results suggest that damaged intestinal crypts in early CD inflammation may not directly trigger certain fibrogenic markers in vitro. This model of the early post-ileal resection state provides a platform to identify key targets for preventing fibrosis progression and potentially reducing the need for repeat ileal surgery in CD patients.