Introduction: A previous study showed that a plant sterol food supplement (PS-FS) improved markers of intestinal inflammation in a cell co-culture model [1]. However, it remains unclear whether these benefits stem from enhanced antioxidant defenses or improved tight junction (TJ) integrity. Methods: This study investigates the effects of PS-FS (2 g PS/dose) on gene expression related to antioxidant defense and TJ proteins using a co-culture model of Caco-2 cells (apical) and RAW264.7 macrophages (basolateral). A bioaccessible fraction of PS-FS was obtained using simulated gastrointestinal digestion (INFOGEST 2.0) and applied to the apical chamber at a non-toxic dilution (1/20, v/v) for 90 min. Inflammation was induced later by adding lipopolysaccharides (1 µg/mL, 24 h) to the basolateral side. The interaction between the co-treatment of PS-FS and budesonide (1 µM/90 min) was examined. The gene expression of transcription factor Nrf2 (NFE2L2) and its target antioxidant enzymes (GSTA1, NQO1, and HMOX-1) was analyzed (qPCR) [2]. Additionally, the gene expression of TJ-related proteins like claudins (CLDN1, CLDN3, and CLDN4), occludin (OCLN), and zonula occludens-1 (TJP1) was assessed. Results: PS-FS increased GSTA1 (27%) and HMOX-1 (124%) gene expression, indicating an activation of the Nrf2 pathway. It also upregulated the TJ proteins CLDN3 (33%), CLDN4 (212%), OCLN (57%), and TJP1 (99%), suggesting a role in restoring the intestinal barrier. However, combining PS-FS with budesonide led to antagonistic effects. Conclusion: PS-FS demonstrated potential in enhancing antioxidant responses and strengthening the intestinal barrier, suggesting that its incorporation into the diet may serve as a nutraceutical intervention for the management of inflammatory bowel disease.

References: [1] Faubel et al. (2024). Food & Function, 15, 6502-6511. [2] Makran et al. (2023). Food & Function, 14, 10829-10840.

Funding: This research is part of the project PID2019-104167RB-I00 funded by MCIN/AEI/10.13039/501100011033. Mussa Makran holds an FPU19/00156 grant from the Ministry of Sciences, Innovation and Universities (Spain).