Ornithine alpha-ketoglutarate metabolism after enteral administration in burn patients: bolus compared with continuous infusion

Abstract

Ornithine alpha-ketoglutarate (OKG) has been successfully used as an enteral supplement in the treatment of catabolic states, including burn injury. However, specific questions remain unanswered concerning burn patients, including OKG metabolism and metabolite production, appropriate mode of administration, and dose. We thus performed a kinetic study and followed plasma ornithine and OKG metabolite concentrations on day 7 postburn in 42 (35 men, 7 women) consecutive burn patients aged 33 +/- 2 y with a mean (+/-SEM) total burn surface area (TBSA) of 31 +/- 1%. Patients were randomly assigned to receive OKG as a single bolus (10 g; n = 13) or in the form of a continuous gastric infusion (10, 20, or 30 g/d over 21 h; n = 13) or an isonitrogenous control (n = 16). Plasma pharmacokinetics of ornithine followed a one-compartment model with first-order input (r = 0.993, P < 0.005). OKG was extensively metabolized in these patients (absorption constant = 0.028 min-1, elimination half-life = 89 min), with the production of glutamine, arginine, and proline; proline was quantitatively the main metabolite [in OKG bolus, area under the curve (AUC)0-7h: proline, 41.4 +/- 5.6 mmol.min/L; glutamine, 20.4 +/- 5.7 mmol.min/L; and arginine, 7.3 +/- 1.9 mmol.min/L]. Proline production was dose-dependent and quantitatively similar between modes of OKG administration. Glutamine and arginine production were not dose-dependent and were higher in the bolus group than in the infusion group. Overall, the bolus mode of OKG administration appeared to be associated with higher metabolite production compared with continuous infusion in burn patients, especially for glutamine and arginine.

No Effect of Bolus Glutamine Supplementation on the Postresectional Adaptation of Small Bowel Mucosa in Rats Receiving Chow ad libitum

“…Our study design is different compared to the study of Vanderhoof et al [29]. Considering the findings of better glutamine plasma levels after a bolus compared to continuous administration of the glutamine precursor ornithine ketoglutarate [35], rats were given a glutamine 2 g/kg/day bolus by gavage in our study, in order to keep a defined supplementation of glutamine per day. During the first 3 days postoperatively, the ras ate <10 g of chow on an ad libitum basis per day.…”

Metabolic fate of glutamine in lymphocytes, macrophages and neutrophils

“…Macrophage-mediated phagocytosis is influenced by glutamine availability (11). Beneficial effects of the provision of glutamine (16) or its precursors (17) have been reported in patients submitted to surgery, radiation treatment or bone marrow transplantation or suffering from injury, sepsis or burns (18).…”

Medical Foods from Natural Sources

“…Metabolites of OKG regulate protein turnover. It was shown that bolus feeding was beneficial in comparison with the continuous infusion with regard to absorption and metabolism of OKG (Bricon et al, 1997).…”