Personalized Ex Vivo Cellular Systems for Ulcerative Colitis: Assessment of the Association Between Patients’ Mayo Score and Gene Expression in Vitro After Inflammation Re-Induction [Conference Winner Abstract]

Introduction Ulcerative colitis (UC) patients often exhibit heterogeneous responses to both conventional and biological therapies [1]. To improve prediction and treatment, personalized ex vivo intestinal organoid-based systems are emerging [2]. Inflammation re-induction in ex vivo cultures is usually performed to mimic inflammatory microenvironment [3]. However, little is known if the magnitude of inflammation in cultured cells accurately reflects the disease features of UC patients. Aim To determine the associations between the Mayo score and the expression of pro-inflammatory marker genes in the inflammatory in vitro co-culture systems of UC patients. Methods The study was approved by the Bioethics Committee (no. BE-2-31, no. 2024-BEC2-465) and performed at the Institute for Digestive Research and the Department of Gastroenterology (LSMU). Demographic, clinical data, colonic biopsies, and peripheral blood of UC patients (n = 17) were collected. Colonic epithelial organoids and peripheral blood monocytes-derived macrophages were used to establish co-cultures. Inflammation re-induction was performed by exogenous stimulation with TNF-α and IFN-γ (10 ng/mL of each) mix for 24 h. The expression of TNF-α, CCL5, and CXCL9 genes were evaluated by quantitative RT-PCR. The Spearman correlation analysis of normalized gene expression values (ΔCT) in co-culture components with endoscopic and full Mayo scores was performed and visualized using RStudio (v. 4.4.1) software, p values < 0.05 were considered statistically significant. Results Association analysis between full Mayo scores and the normalized expression of pro-inflammatory marker genes in both colonic epithelial cell and macrophage compartments showed weak (Rho (epithelial cells) = 0.10 [TNF-α], 0.31 [CXCL9], -0.38 [CCL5]; Rho (macrophages) = 0.31 [TNF-α], 0.16 [CXCL9], 0.32 [CCL5]) but insignificant (p (epithelial cells) = 0.69 [TNF-α], 0.22 [CXCL9], 0.13 [CCL5]; p (macrophages) = 0.23 [TNF-α], 0.53 [CXCL9], 0.20 [CCL5]) correlations. Similar trends in both co-culture cell types were also observed when assessing the associations between the normalized expression of selected genes and endoscopic Mayo subscores: Rho (epithelial cells) = -0.03 [TNF-α], 0.33 [CXCL9], -0.30 [CCL5] and Rho (macrophages) = 0.22 [TNF-α], 0.05 [CXCL9], -0.17 [CCL5]; p (epithelial cells) = 0.91 [TNF-α], 0.19 [CXCL9], 0.24 [CCL5] and p (macrophages) = 0.39 [TNF-α], 0.85 [CXCL9], 0.53 [CCL5]. Conclusions In conclusion, the expression of TNF-α, CCL5, and CXCL9 genes in personalized inflamed ex vivo co-cultures consisting of colonic epithelial cells and macrophages did not significantly correlate with the Mayo scores of UC patients.