CONICET | Buscador de Institutos y Recursos Humanos

Streptococcus (S.) thermophilus CRL1190, isolated from homemade yoghurt, is an efficient producer of capsular and exo‐ polysaccharides (EPS1190) which confers viscosity to fermented milks. Therapeutic effect of S. thermophilus CRL1190‐fermented milk on chronic gastritis has recently been shown. The beneficial effects observed were induction of mucus formation, increase in regulatory cytokines (IL‐10) and reduction in pro‐inflammatory cytokines (INF‐γ and TNF‐α). The objective of this work was to determine the effects of EPS1190 on human gastric epithelial cells (AGS), human buccal mucosal cells (KB) and murine macrophages (RAW 264.7). For that, EPS1190 was isolated from skim milk fermented with S. thermophilus CRL1190, subjected to acetylation,hydrolyzed and analyzed by GC‐MS. The polysaccharide is composed of 33 % glucose and 66 % galactose with 1,4‐ and 1,4,6‐galactose residues as main building blocks beside a high amount of 1,4‐linked glucose. In vitro assays revealed that EPS1190 stimulates cellular vitality and proliferation of human stomach AGS cells and human buccal KB cells significantly as wells as the phagocytosis rate of murine macrophages RAW264.7. The effect of EPS1190 on nitric oxide (NO) releasing by macrophages activated with lipo‐polyssacharide (LPS) was similar to the untreated control. The interaction of EPS 1190 with both AGS cells and human stomach tissue section was analysed by confocal laser scanning microscopy (CLSM); observations revealed the partial internalization of EPS1190 into AGS cells via endosomes, and the bioadhesive absorption of FITC‐labeled EPS1190 into the mucus layer on the apical side of the epithelium. Summarizing, EPS1190 seems to stimulate epithelial cell regeneration which in turn may rationalize its use as cytoprotective compound in probiotic preparations.