A multi-fibre mix inhibits the inflammation process in dextran sodium sulfate-induced colitis and leads to a relative increase of regulatory T-cells in mesenteric lymph nodes

Inflammatory bowel disease (IBD) is a multi-causal idiopathic disease; as many as a quarter of IBD patients experience the first symptoms during childhood. Weight loss, growth failure and frequent nutrient deficiencies are most commonly associated with paediatric IBD. Nutritional therapy has shown to be an important and effective way in the management of IBD, especially in growing children. The present study aimed to analyse the effects of a multifibre mix, comprising beta-galacto-oligosaccharide, fructan, non-digestible alpha-glucan, and hemicellulose, on dextran sodium sulfate (DSS)-induced colitis. The DSS-induced colitis mouse model is widely used to study both the acute and chronic IBD-related mechanisms and interventions. Recent studies indicate that an imbalance between T helper cell (Th) subsets contributes to the DSS-induced inflammation process. Dietary supplementation of the multi-fibre mix (1.5% of the total diet) during 2 weeks prior to the DSS-challenge largely prevented the DSS-induced weight loss and changes in stool consistency. After 7 days of DSS treatment, animals were sacrificed. Serological and histological evaluations showed deterioration of gut integrity, elevated serum amyloid A and raised mesenteric lymph node (MLN) cell number by DSS. Multi-fibre mix supplementation significantly reduced these DSS-induced effects. Further analyses of the MLNs by flow cytometry demonstrated a 2.6- , 3.5- and 3.2-fold increase of the number of T-helper type 1 (Th1) cells, Th2 cells and regulatory T-cells, respectively, by DSS in comparison to the control animals. The number of Th17 cells increased 6.8-fold by DSS, pointing to a strong Th17-driven disease process in the MLN. The multi-fibre mix significantly counteracted the DSS-induced increase of these Th17 cells in the MLN, whereas the regulatory T-cell numbers remained more abundant. This resulted in a relative increase in regulatory T-cell count compared to the other T-cell subsets. In conclusion, DSS-induced colitis leads to strong Th17-driven responses in the MLNs. Dietary supplementation of a multi-fibre mix effectively reduces systemic and local inflammatory disease symptoms, which might be, at least partially, mediated by a relative increase of the regulatory T-cell number in MLNs. This may lead to new ways to optimise nutritional therapy strategies in IBD management.