Glutamine-supplemented total parenteral nutrition attenuates plasma interleukin-6 in surgical patients with lower disease severity

Abstract

Aim: Previous reports have shown that decrease in plasma glutamine (Gln) level following major surgery may contribute to the state of immunosuppression. Gln supplementation improves the depletion of body Gln pool, and may have indirect effect on reducing proinflammatory mediator release. This study evaluated whether the effect of Gln dipeptide-enriched total parenteral nutrition (TPN) on postoperative cytokine alteration depended on the disease severity of surgical patients.

Methods: Forty-eight patients with major abdominal surgery were allocated to two groups to receive isonitrogenous (0.228 g nitrogen/kg per d) and isocaloric (30 kcal/kg per d) TPN for 6 d. Control group (Conv) using conventional TPN solution received 1.5 g amino acids/kg per day, whereas the test group received 0.972 g amino acids/kg per day and 0.417 g L-alanyl-L-glutamine (Ala-Gln)/kg per day. Blood samples were collected on d 1 and d 6 postoperatively for plasma interleukin (IL)-2, IL-6, IL-8, and interferon (IFN)-gamma analysis.

Results: Plasma IL-2 and IFN-gamma were not detectable. IL-6 concentrations were significantly lower on the 6(th) postoperative day in the Ala-Gln group than those in the Conv group in patients with APACHE II <=6, whereas no difference was noted in patients with APACHE II >6. There was no difference in IL-8 levels between the two groups. No difference in cumulative nitrogen balance was observed on d 2-5 after the operation between the two groups (Ala-Gln -3.2+/-1.6 g vs Conv -6.5+/-2.7 g). A significant inverse correlation was noted between plasma IL-6 levels and cumulative nitrogen balance postoperatively in the Ala-Gln group, whereas no such correlation was observed in the Conv group.

Conclusion: TPN supplemented with Gln dipeptide had no effect on plasma IL-8 levels after surgery. However, Gln supplementation had a beneficial effect on decreasing systemic IL-6 production after surgery in patients with low admission illness severity, and lower plasma IL-6 may improve nitrogen balance in patients with abdominal surgery when Gln was administered.