Glutamine‐Supplemented Parenteral Nutrition Improves Gut Mucosa Integrity and Function in Endotoxemic Rats

Abstract

The effects of glutamine-supplemented parenteral nutrition on protein metabolism, small intestinal mucosal metabolism, morphology, and barrier function were studied in endotoxin-treated rats. Forty-six male Wistar rats were randomized to two groups of 23 animals each and received total parenteral nutrition solutions supplemented with either glutamine (GLN group) or glycine (GLY group) at 2% wt/vol. Endotoxemia was induced by continuous intravenous infusion of endotoxin at a dose of 2 mg/kg per day throughout the 4-day study period. The GLN group had a less-negative cumulative nitrogen balance (-14.0 +/- 132.8 mg of nitrogen in the GLN group and -86.8 +/- 161.7 mg of nitrogen in the GLY group, p < .05) and less cumulative excretion of urinary 3-methylhistidine (2910 +/- 593 nmol) than the GLY group (4447 +/- 933 nmol, p < .01). Jejunal mucosal glutaminase activity and the arterio-portal venous blood glutamine concentration differences were significantly higher in the GLN group compared with the GLY group (15.6 +/- 2.3 vs 11.1 +/- 1.9 mumol/g per minute, p < .05, and 181 +/- 52 vs 147 +/- 36 nmol/mL, p < .05, respectively). The morphology of the jejunal mucosa in the GLN group was significant for having greater mucosal weight (23.4 +/- 3.1 vs 17.6 +/- 2.5 mg/cm), villus height (445 +/- 75 vs 357 +/- 57 microns), crypt depth (197 +/- 34 vs 161 +/- 28 microns), and wall thickness (751 +/- 77 vs 648 +/- 102 microns) than the GLY group (p < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Glutamine and intestinal barrier function

“…The results indicated that provision of Gln blunts mucosal injury and the incidence of bacterial translocation (Souba et al 1990). It has also been demonstrated that administration of Gln improves gut barrier function and reduces bacterial translocation in both in vivo (Chen et al 1994;Souba et al 1990) and in vitro (Scheppach et al 1996) models of gut disorder. Furthermore, Gln deprivation facilitates TNF-a-induced bacterial translocation in Caco-2 cells, and the sensitization of TNFa-induced bacterial translocation was blocked by an inhibition of the conversion of Gln to a-ketoglutarate (a-KG), a key step in oxidative metabolism of Gln (Clark et al 2003).…”

Gut Glutamine Metabolism at Different Stages of Sepsis in Rats

“…On the other hand, as long as sepsis remains in the early stage, when gut glutamine extraction increases, the effect of glutamine supplementation on intestinal glutamine utilization could be enhanced. Considering previous investigators reported that an increase in intestinal glutamine utilization improves mucosal cellularity 36 and digestive function, 37 and maintains intestinal barrier function, 36,38 these advantages could be prominent in the early stage of sepsis.…”

Regulatory Effect of Histamine on the Barrier Function of Intestinal Mucosal

“…33,34 Ingredients of food, such as glutamine and some special fibers, are important for sustaining the integrity of mucosa. [35][36][37] But these cannot adequately maintain the modulatory mechanism of mucosal barrier on physiological and pathological conditions.…”