Fecal water from ileostomic patients consuming oat beta-glucan enhances immune responses in enterocytes

Yeast, fungal, and dietary beta-glucans have immune-modulating effects in vitro and in vivo, as thought, mainly by affecting leukocytes; however, effects of oat beta-glucan on enterocytes have never been studied. As recognized, supplying oat beta-glucans as such to cells in culture directly is difficult because of solubility problems. Therefore, six ileostomic patients consumed, in random order, a control diet or an oat beta-glucan enriched diet (5 g) and from the collected ileostomic content, fecal water was prepared and added to two small intestinal cell lines (INT407, Caco-2) and two colon cell lines (HT29, T84) together with a cytokine cocktail (IL-1beta + INFgamma + TNFalpha). Several parameters reflecting immune-modulation were measured. As compared to placebo fecal water, beta-glucan enriched fecal water significantly increased IL-8 production in HT29 (5.0%; p = 0.046) and INT407 cells (22.0%; p = 0.028). Intercellular adhesion molecule (ICAM)-1 expression increased in T84 (11.0%; p = 0.028) and Caco-2 cells (20.4%; p = 0.075). These immune-stimulating effects were confirmed by enhancement of inflammatory expression profiles, as determined with an antibody array. Our findings show immune enhancement by fecal water from ileostomic patients consuming oat beta-glucan both in small intestinal and colon cell lines after stimulation, which is in agreement with documented effects in leukocytes. Whether these immune-stimulating effects on enterocytes contribute to the enhanced protection of the host against invading pathogens as observed both in animals and in humans, as well as the underlying mechanism, needs further evaluation.     

Heme oxygenase induction by cyanidin-3-O-beta-glucoside in cultured human endothelial cells

The aim of the present research was to investigate the effect of cyanidin-3-O-beta-glucoside (C3G) on heme oxygenase-1 (HO-1), endothelial nitric oxide synthase (eNOS), inducible NOS (iNOS) and dimethylarginine dimethylamino hydrolase-2 (DDAH-2) expression in cultured endothelial cells. Different concentrations (0.00625-250 microM) of C3G were tested in order to investigate possible beneficial and harmful effects of C3G. Our data demonstrated that C3G increased the induction of eNOS and HO-1 in a dose-dependent manner. Higher concentration (62.5-250 microM) also resulted in increase of isoprostane, cGMP and PGE2 levels and in induction of iNOS with consequent oxidative stress. In conclusion, our data evidence that C3G may exert various protective effects against endothelial dysfunction, whereas potentially harmful effects of C3G appear to be limited to concentrations very difficult to be reached in physiological conditions unless there is abundant oral supplementation.     

Visualization of astaxanthin localization in HT29 human colon adenocarcinoma cells by combined confocal resonance Raman and fluorescence microspectroscopy

Astaxanthin, a carotenoid found in plants and seafood, exhibits antiproliferative, antioxidant and anticarcinogenic properties. We show that astaxanthin delivered with tetrahydrofuran is effectively taken up by cultured colon adenocarcinoma cells and is localized mostly in the cytoplasm as detected by confocal resonance Raman and broad-band fluorescence microspectroscopy image analysis. Cells incubated with beta-carotene at the same concentration as astaxanthin (10 microM) showed about a 50-fold lower cellular amount of beta-carotene, as detected by HPLC. No detectable Raman signal of beta-carotene was found in cells, but a weak broad-band fluorescence signal of beta-carotene was observed. beta-Carotene, like astaxanthin, was localized mostly in the cytoplasm. The heterogeneity of astaxanthin and beta-carotene cellular distribution in cells of intestinal origin suggests that the possible defense against reactive molecules by carotenoids in these cells may also be heterogeneous.     

Suppression of immune responses to β‐lactoglobulin in mice by the oral administration of peptides representing dominant T cell epitopes

BACKGROUND: The significance of oral tolerance in the treatment of adverse immune reactions such as allergic and autoimmune diseases has been noted. In the present study, peptides that could effectively induce oral tolerance to bovine β‐lactoglobulin (BLG), a milk allergen, were investigated in a murine model. RESULTS: The oral administration of peptides corresponding to the T cell epitope regions of BLG, i.e. p42–56, p62–76 and p139–154, apparently down‐regulated T cell proliferation to BLG. The in vitro cytokine production by the lymph node cells from the peptide‐fed mice cultured in the presence of the antigen was also analysed. It was found that p62–76 and p139–154 feeding suppressed the production of both Th1 and Th2 types. Interestingly, p139–154 feeding suppressed both T cell and antibody responses to BLG. Additionally, p139–154 feeding diminished BLG‐specific IgE and IgG1 antibody responses. CONCLUSION: The unique tolerogen peptide p139–154 that could suppress both T and B cell responses to BLG in a murine model was identified. These findings can be useful for the selection of an optimum tolerogenic peptide to prevent and treat milk and other food allergies. Copyright © 2007 Society of Chemical Industry