Alteration in enterocyte gene expression may explain structural and functional changes following glutamine supplemented parenteral nutrition.

Abstract

Following extensive bowel resection, the intestinal tract undergoes a variety of adaptive responses to enhance bowel function. The purpose of this study was to determine the effect of glutamine-supplemented parenteral nutrition on mucosal cellularity and gut function. In addition, enterocyte gene expression of two relevant systems was also characterized and related to the structural and functional changes that occurred. Male Wistar rats underwent a 60% small bowel resection and jugular vein catheterization and were randomized into two groups. The control group (n = 10) received a standard intravenous nutritional solution and the study group (n = 10) received a similar solution but enriched with alanylglutamine dipeptide. After 7 days blood was taken for amino acid analysis, and bowel was harvested to determine mucosal morphology and expression of mucosal cell glutaminase and IGF-I mRNA. Mesentery lymphnodes were cultured to determine the presence of bacteria and thus access bacteria translocation. Serum glutamine concentration and mucosal architecture were maintained in the study group compared to the controls. Seventy percent of lymphnodes were cultured positive in control vs. only 20% in the study group (P < 0.05). Jejunal mucosal glutaminase and ileum mucosal IGF-I mRNA increased twofold and threefold respectively compared to control animals. Parenteral nutrition supplemented with alanyl-glutamine dipeptide supports mucosal cellularity and regional immune function in rodents following intestinal resection, These alterations are associated with enhanced enterocyte expression of glutaminase and IGF-I. These changes may facilitate the structural and functional alterations which were observed in the glutamine treated animals.