Lectins can reverse the distal intestinal atrophy associated with elemental diets in mice

Background: Elemental diets cause intestinal atrophy and reduced intestinal integrity, which can lead to significant increases in intestinal permeability and bacterial translocation. Recently, several lectins have been shown to have trophic effects on the intestine. Aims: We examined the effects of concanavalin-A and phytohaemagglutinin on cell proliferation and crypt fission throughout the intestine of mice fed on elemental diets. Methods: Mice were randomized to chow fed, elemental diet, elemental diet plus concanavalin-A and elemental diet plus phytohaemagglutinin groups. Cell proliferation and crypt fission were estimated in microdissected crypts. Plasma gastrin and enteroglucagon levels were measured by radioimmunoassay. Results: Elemental diet feeding significantly decreased cell proliferation and crypt fission of the middle and distal small intestine and throughout the colon. Phytohaemagglutinin significantly increased the weight of the intestine, but concanavalin-A had little effect. Cell proliferation in the small intestine was significantly increased by both lectins. However, in the stomach and colon, only phytohaemagglutinin increased proliferation. Crypt fission in the colon was dramatically increased by phytohacmagglutinin. Phytohaemagglutinin increased the plasma gastrin level, but not the enteroglucagon level. Conclusions: Lectins have significant trophic effects on the small intestine and colon of mice fed elemental diets, and these actions vary between different sites in the gastrointestinal tract.