Mucosal epithelial barrier repair to maintain pig health

Abstract

Mucosal barrier function is critical to prevent translocation of microorganisms and their toxins. The intestinal barrier is made up of a single layer of columnar epithelium that can be readily breached by enteric infections, but has a tremendous capacity to repair. Thus, mucosal epithelial repair is one of the most critical elements of maintaining an intact barrier. In the small intestine, villous contraction is the initial phase of repair. Subsequent events include crawling of healthy epithelium adjacent to the wound, referred to as restitution. However, restoration of a continuous layer of epithelium is insufficient to restore barrier function. Recent ex vivo studies of porcine small intestine have revealed the importance of closure of the interepithelial tight junctions and the paracellular space. The critical role of tight junction closure is underscored by the prominent contribution of the paracellular space to measures of barrier function such as transepithelial electrical resistance. The net result of reparative mechanisms is remarkably rapid closure of mucosal wounds in porcine tissues to prevent the onset of sepsis.