GLUTAMINE DIPEPTIDES-SUPPLEMENTED PARENTERAL-NUTRITION REVERSES GUT MUCOSAL STRUCTURE AND INTERLEUKIN-6 RELEASE OF RAT INTESTINAL MONONUCLEAR-CELLS AFTER HEMORRHAGIC-SHOCK

Glutamine is an essential substrate for gut mucosal structure, but the role for gut immune function is not fully known. To determine the eff ect on gut cytokine release in relation to bacterial translocation and gut morphology, a nonlethal hemorrhagic shock (30 min, 30 mmHg) was p erformed in male Wistar rats followed by 4 days of different way of fe eding. A conventional total parenteral nutrition (TPN) solution was co mpared with an isocaloric and isonitrogenous TPN solution supplemented with alanin-L-glutamine and glycyl-L-glutamine. An enteral chow-fed c ontrol group was included. Gut mononuclear cells and splenic macrophag es were obtained and endotoxin-induced supernatant tumor necrosis fact or-alpha (TNF) and interleukin-6 (IL-6) bioactivity was measured. Hist ological specimen of the small bowel were taken and mesenteric lymph n odes (MLN) were separated. Enteral feeding following hemorrhagic shock was accompanied by a normal mucosal structure and no bacterial transl ocation could be detected. TPN was characterized by suppression of cyt okine release in gut mononuclear cells and splenic macrophages compare d with the enteral-fed control (p < .05). Decreased TNF and IL-6 relea se was associated with a significantly increased mucosal injury score Go <.05) and a high incidence of bacterial translocation to MLN (66%, p < .05 vs. control). Supplementation of glutamine-dipeptides did not prevent TPN-induced bacterial translocation to MLN (p < .05 vs. contro l) but significantly improved mucosal injury (p < .05 vs. TPN). Down-r egulation of TNF release in TPN-fed rats could not be reversed by glut amine dipeptides while IL-6 release was significantly increased compar ed with TPN-fed animals (p < .05), and no difference to enteral-fed co ntrols could be found. Enteral nutrition following hemorrhagic shock i s superior to parenteral nutrition with regard to mucosal structure, c ytokine release, and bacterial translocation. Supplemention of TPN wit h glutamine dipeptides could reverse TPN-induced suppression of IL-6 r elease and improved mucosal structure, which may be beneficial in vari ous disease conditions in which TPN is an integrated part of patients management.