Total parenteral nutrition supplemented with L-alanyl-L-glutamine and gut structure and protein metabolism in septic rats.

The effects of administering total parenteral nutrition (TPN) supplemented with the dipeptide of L-alanyl-L-glutamine (Ala-Gln) on gut structure, barrier function, and protein metabolism were investigated in septic rats. Sepsis was induced by the continuous intraperitoneal administration of endotoxin via a miniosmotic pump. Twenty-three rats were divided into two groups and fed parenterally for 5 days. The Ala-Gln group (n = 11) received a conventional TPN solution supplemented with 2% Ala-Gln, whereas the control group (n = 12) received conventional TPN solution alone. One rat in each group died of endotoxemia. The groups showed similar nitrogen balance, urinary excretion of 3-methylhistidine, and plasma concentration of endotoxin in the portal vein. The groups showed similar incidence of bacterial translocation from the gut to the mesenteric lymph nodes. The intestinal mucosal weight and villous height were significantly greater in the Ala-Gln group than in the control group. Pathological derangement of the mucosal structure was more marked in the control group than in the Ala-Gln group. These results suggest that TPN supplemented with Ala-Gln preserves the gut structure without decreasing the nitrogen balance under septic conditions.