In vivo effects of dietary (1→3), (1→4)-β-D-glucans from oat on mucosal immune responses in man and mice.

Objective: Antimicrobial peptides and tight junction proteins are crucial to maintain mucosal immunity. It is known that oat β-glucan may affect intestinal immunity. Therefore, the aim of the present study was to evaluate the effect of oat β-glucan on the presence of antimicrobial peptides and tight junction protein.

Dietary (1-->3), (1-->4)-beta-D-glucans from oat activate nuclear factor-kappaB in intestinal leukocytes and enterocytes from mice.

Dietary components, like beta-glucans, can modulate the intestinal immune response. We previously showed that fecal water enriched with oat beta-glucan stimulated the cytokine-induced immune response of enterocytes. It is, however, unclear whether beta-glucans activate nuclear factor-kappaB (NF-kappaB) pathways in the intestine in vivo and if so, whether enterocytes, intestinal leukocytes, or both respond to beta-glucans.

Effects of mushroom-derived beta-glucan-rich polysaccharide extracts on nitric oxide production by bone marrow-derived macrophages and nuclear factor-kappaB transactivation in Caco-2 reporter cells: can effects be explained by structure?

Mushrooms are known for their immune-modulating and anti-tumour properties. The polysaccharide fraction, mainly beta-glucans, is responsible for the immune-modulating effects. Fungal beta-glucans have been shown to activate leukocytes, which depend on structural characteristics of beta-glucans.

The absence of functional dectin-1 on enterocytes may serve to prevent intestinal damage.

Background: Enterocytes are exposed to antigens present in the intestinal lumen, like beta-glucans that are carbohydrate structures present not only in the cell wall of yeast and fungi but also in cereals. Beta-glucans are known for their immune modulating properties and we have earlier reported an increased immune response by enterocytes after addition of fecal water prepared from ileostomic contents obtained from participants consuming an oat beta-glucan diet versus a placebo diet. We hypothesized that our observation of immune stimulating effects by oat beta-glucan in enterocytes was mediated through the beta-glucan receptor dectin-1.

Dietary modulation of immune function by beta-glucans.

The immune response can be modulated by nutrients like beta-glucans, which are glucose polymers that are major structural components of the cell wall of yeast, fungi, and bacteria, but also of cereals like oat and barley. There is a lot of structural variation in the beta-glucans from these different sources, which may influence their physiological functions. In this review the current status concerning possibilities to modulate immune function by beta-glucans is discussed.

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).