Efficiency of a cysteine-taurine-threonine-serine supplemented parenteral nutrition in an experimental model of acute inflammation

Abstract

Objective: As is the case with glutamine, requirements for amino acids such as cysteine, taurine, and serine may be increased in stress situations. This study evaluated the potential usefulness of supplementation of total parenteral nutrition with a cysteine, taurine, threonine, and serine mixture (SEAS), with or without glutamine, in an experimental model of turpentine-induced acute inflammation.

Design and setting: Prospective, controlled animal study in male Sprague-Dawley rats.

Interventions: Twenty-seven rats received isonitrogenous, isocaloric total parenteral nutrition (260 kcal/kg, 2 gN/kg per day) for 5 days. They were divided into three groups according to the composition of the amino acid admixture: standard amino acids (control, n=9), standard amino acids partly substituted with SEAS (n=10) or with SEAS and glutamine (n=8). All rats received two subcutaneous turpentine injections (0.5 ml/100 g) 24 h (day 2) and 72 h (day 4) after the initiation of parenteral nutrition and were killed on day 5.

Measurements and results: Nitrogen balance was significantly increased (control 53+/-29, SEAS 153+/-21, SEAS+Gln 187+/-32 mg/24 h) and urinary 3-methylhistidine/creatinine ratio decreased (control 55+/-4, SEAS 43+/-4, SEAS+Gln 38+/-3 micro mol/mmol) on day 5 in the two SEAS-treated groups. Hepatic and extensor digitorum longus muscle protein contents were significantly higher in the SEAS+Gln-treated group than in the other two groups. In addition to slight differences in liver amino acid content, other parameters including liver glutathione did not differ significantly between groups.

Conclusions: Improved nitrogen balance and reduction in urinary 3-methylhistidine suggest that SEAS supplementation improves nitrogen homeostasis in an experimental model of acute inflammation. Glutamine addition further improves protein status.