Role of Glutamine in Protection of Intestinal Epithelial Tight Junctions.

Glutamine, a conditionally essential amino acid, is consumed predominantly in the gastrointestinal tract as a source of energy, particularly under the conditions of trauma, sepsis and surgery. In this article, we discuss the unique role of glutamine in the preservation of epithelial barrier function in the gastrointestinal tract. Glutamine supplementation protects the gastrointestinal mucosal homeostasis during total parenteral nutrition, diarrhea, radiation injury, starvation, sepsis and trauma. A significant body of evidence indicates that glutamine preserves the gut barrier function and prevents permeability to toxins and pathogens from the gut lumen into mucosal tissue and circulation. Recent studies demonstrated that the mucosal barrier protective effect of glutamine relates to its effect on preservation of epithelial tight junction integrity. The current understanding of glutamine-mediated protection of intestinal epithelial tight junction integrity and the potential mechanisms involved in this protective effect of glutamine are discussed.