Development of the epithelium of the intestinal tract and its participation in the defense of the organism in mammals

This document aims was review the mechanism of development and differentiation of intestinal epithelium (IE) and is participation in the defense of the organism. The IE has as main function the absorption of nutrients, it is exposed to a wide variety of microorganisms that come with the food, and could alter the intestinal barrier, for this reason the epithelium has evolutionarily conserved mechanisms dealing with the immediate defense depending on the stage of development of the individual, called innate system, as well as of a specific immune system. The epithelium has physical, chemical and biological means to maintain the integrity of the defensive barrier against pathogens, such as tigh junctions, layer of mucus, interaction with antimicrobial peptides, immune cells, absortive and secretory cells, which seem to have an important role as presenters of antigens, which could be linked to the presentation of the microflora to generate tolerance state. On the other hand, the innate immune system of the intestine has a variety of components inside which included the presence of sensors (TLRs and NOD) in epithelial cells whose function recognize microbial structures, leading the production of multiple non-specific antimicrobial substances for controlling pathogenic and nonpathogenic microbial population. We concluded that intestinal epithelium presents complex mechanisms that help maintaining the homeostatic balance of the body, through the production of substances that are responsible for regulating the processes of absorption of nutrients and the maintenance of the microflora.