Hydrolysates from different food sources show protective effects on the intestinal epithelial barrier

Recently, dietary molecules are more and more recognized to, besides having a nutritional function, act directly on functionalities of the intestine. For example, several hydrolyzed dietary proteins (hydrolysates) were found to show immunomodulating effects. Increased permeability of the epithelial barrier, an important aspect of the intestinal immune system, is associated with various intestinal and systemic diseases.

We investigated the effect of hydrolysates on epithelial permeability in the T84 intestinal epithelial cell monolayer model.  Polarized T84 cells were pre-incubated with hydrolysates and stimulated with the proinflammatory phorbol-12-myristate-13-acetate (PMA). Transepithelial electrical resistance (TEER) was analyzed as a measure for tight junction–mediated barrier function.

Hydrolysates from different sources (soy, wheat and cow’s milk) attenuated the PMA induced permeability increase. For cow’s milk hydrolysates, the observed effect seems to depend on the cow’s milk fraction (whey or casein) and hydrolysis.

Overall, specific hydrolysates show protective effects on the epithelial barrier. However, the underlying mechanisms are unknown. Since Toll-like receptor 2 and 9 activation is associated with increased epithelial integrity, and the protective hydrolysates stimulate these receptors, we hypothesize that protective hydrolysates confer their effect via these TLRs. More research is needed to confirm this. Ultimately,  this knowledge will lead to a better understanding of how nutrition can contribute to improving health via direct effects on the intestines.