Is additional enrichment of diet in branched-chain amino acids or glutamine beneficial for patients receiving total parenteral nutrition after gastrointestinal cancer surgery?

Objectives: Total Parenteral Nutrition (TPN) is necessary in patients unable to receive oral or enteral feeding for a period of at least 7 days. Branched-chain amino acids (BCAA): valine (Val), leucine (Leu), and isoleucine (Ile) are essential amino acids, which are important regulators in protein metabolism. They are also the main nitrogen source for glutamine synthesis in muscles. In this process they undergo irreversible degradation and cannot be reutilised for protein synthesis. In catabolic states, like cancers, glutamine demand increases and therefore also its utilisation, which can decrease the level of BCAA required for Gln synthesis. The purpose of this study was to evaluate the necessity of BCAA or glutamine-enriched TPN in patients after gastrointestinal cancers surgery.
Material and Methods: Our aim was to investigate changes of plasma BCAA and glutamine concentrations in patients operated for colorectal, small intestine or pancreatic cancer and who are either receiving TPN or not in the postoperative period. Free amino acids plasma concentrations were determined by the ion-exchange chromatography.
Results: Surgery in the control group caused a decrease in Val, Ile and Leu concentrations in the postoperative period. In TPN patients this depression was inhibited beginning from the third day after surgery, except for Val and Leu in colorectal cancer group. In control and TPN patient groups, Gln concentration decreased after the surgery and subsequently increased beginning from the third day after the operation.
Conclusions: Gastrointestinal cancer patients' surgery results in decrease in BCAA concentrations. Standard TPN exerts a beneficial effect on the BCAA level in patients with pancreatic and small intestine cancer. In colorectal cancer such TPN should be enriched with Leu and Val.