Age-Dependent Intestinal Repair: Implications for Foals with Severe Colic

SIMPLE SUMMARY: Equine colic places a substantial financial burden on horse owners and the equine industry each year. Equine veterinary research is focused on preventing colic on the farm whenever possible and improving treatment options available to veterinarians in the field and referral hospitals. It is important for scientists to have a detailed understanding of the intestinal damage created by different types of colic in foals and adult horses so they can better target certain cell types or tissue systems when investigating new treatment options. This review article summarizes recent works in the field of intestinal injury research and describes the potential roles of various intestinal systems, such as the enteric nervous system (ENS), in repairing the intestine after colic injury and how these systems mature in early life. ABSTRACT: Colic is a leading cause of death in horses, with the most fatal form being strangulating obstruction which directly damages the intestinal barrier. Following surgical intervention, it is imperative that the intestinal barrier rapidly repairs to prevent translocation of gut bacteria and their products and ensure survival of the patient. Age-related disparities in survival have been noted in many species, including horses, humans, and pigs, with younger patients suffering poorer clinical outcomes. Maintenance and repair of the intestinal barrier is regulated by a complex mucosal microenvironment, of which the ENS, and particularly a developing network of subepithelial enteric glial cells, may be of particular importance in neonates with colic. Postnatal development of an immature enteric glial cell network is thought to be driven by the microbial colonization of the gut and therefore modulated by diet-influenced changes in bacterial populations early in life. Here, we review the current understanding of the roles of the gut microbiome, nutrition, stress, and the ENS in maturation of intestinal repair mechanisms after foaling and how this may influence age-dependent outcomes in equine colic cases.