Increasing plasma glutamine in postoperative patients fed an arginine-rich immune-enhancing diet--a pharmacokinetic randomized controlled study.
OBJECTIVE
Immune-enhancing diets (IEDs) rich in arginine (ARG) reduce morbi-mortality in trauma and surgical patients. Among the pharmaconutrients inducing these effects, ARG may be involved by generating active metabolites such as glutamine (GLN). However, the ability of an ARG-enriched diet to normalize GLN plasma levels in intensive care unit (ICU) patients has never been documented. To analyze plasma GLN and related amino acid (AA) kinetics in response to an ARG-enriched IED in ICU surgical patients.


METHODS
This prospective, randomized, single-blind, comparative study was performed on 22 patients randomized to receive total enteral nutrition for 7 days with either an ARG-enriched IED or a standard formula (rendered isonitrogenous to the IED, S group, n = 11), providing 30 kcal/kg/day and 0.3 g N/kg/day.


METHODS
Plasma AA concentrations were measured on day 5 after a 3-hour washout period (basal values = T0) and after 30, 60, 90, 120, 180, and 360 minutes of enteral nutrition. The primary end point was the variation in plasma GLN from T0 to T90.


RESULTS
Only the IED-fed patients showed an increase in plasma levels of GLN (differences [T90 - T0]: +40 +/- 6 vs. -35 +/- 18 micromol/L, mean +/- sem, p < 0.05, two-way analysis of variance), ARG (+35 +/- 5 vs.+1 +/- 4 micromol/L, p < 0.05), ornithine (+23 +/- 6 vs. -2 +/- 2 micromol/L, p < 0.05), and proline (+36 +/- 10 vs. -6 +/- 11 micromol/L, p < 0.05).


CONCLUSIONS
To our knowledge, this is the first reported pharmacokinetic study on an IED even though these products have been on the market for 20 years. Our main result is that administering an ARG-enriched IED causes a significant increase in plasma GLN probably from de novo GLN synthesis from ARG. This suggests that the ARG present in IED can serve to supply GLN to ICU patients, who are usually depleted in this conditionally essential AA during injury.
Loï
Cécile
C
Laboratoire de Biologie de la Nutrition, Faculté de Pharmacie, Université Paris Descartes, France. cecile.loi@nutrition-paris5.org
Zazzo
Jean-Fabien
JF
Delpierre
Eric
E
Niddam
Claire
C
Neveux
Nathalie
N
Curis
Eric
E
Arnaud-Battandier
Franck
F
Cynober
Luc
L
D000368:Aged; D000369:Aged, 80 and over; D001120:Arginine / Q000008:administration & dosage / Q000276:immunology / Q000493:pharmacokinetics*; D004035:Diet Therapy / Q000379:methods*; D004750:Enteral Nutrition; D005260:Female; D005973:Glutamine / Q000097:blood*; D006801:Humans; D007107:Immune System; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D011446:Prospective Studies; D014947:Wounds and Injuries / Q000178:diet therapy*
D005973:Glutamine; D001120:Arginine