Helminths' therapeutic potential to treat intestinal barrier dysfunction.

The intestinal barrier is a dynamic multi-layered structure which can adapt to environmental changes within the intestinal lumen. It has the complex task of allowing nutrient absorption while limiting entry of harmful microbes and microbial antigens present in the intestinal lumen. Excessive entry of microbial antigens via microbial translocation due to 'intestinal barrier dysfunction' is hypothesised to contribute to the increasing incidence of allergic, autoimmune and metabolic diseases, a concept referred to as the 'epithelial barrier theory'. Helminths reside in the intestinal tract are in intimate contact with the mucosal surfaces and induce a range of local immunological changes which affect the layers of the intestinal barrier. Helminths are proposed to prevent, or even treat, many of the diseases implicated in the epithelial barrier theory. This review will focus on the effect of helminths on intestinal barrier function and explore whether this could explain the proposed health benefits delivered by helminths.