Related Experiment Videos
Glutamine metabolism in very low birth weight infants
Insights
This study quantifies glutamine metabolism in premature infants, finding that low-dose glutamine supplementation does not alter leucine metabolism or overall glutamine flux in very low birth weight neonates.
Area of Science:
- Biochemistry
- Neonatology
- Nutritional Science
Background:
- Premature infants have unique metabolic needs.
- Glutamine is crucial for infant metabolism and gut health.
- Understanding glutamine kinetics is vital for optimizing nutrition in neonates.
Purpose of the Study:
- To quantify glutamine kinetics in premature infants.
- To determine if glutamine supplementation affects leucine metabolism.
- To assess splanchnic extraction of glutamine in neonates.
Main Methods:
- Stable isotope infusions (L-[2H3]leucine, L-[13C5]glutamine, L-[I-13C]leucine, L-[I-13C]glutamine) in 11 very low birth weight neonates.
- Comparison between a control group (hypocaloric formula) and a glutamine-supplemented group (0.2 g.kg-1.d-1).
- Measurement of plasma isotopic enrichments to determine rates of appearance and splanchnic extraction.
Main Results:
- Leucine release from protein breakdown was similar between groups.
- Glutamine de novo synthesis comprised over 80% of glutamine appearance and was not significantly different between groups.
- Splanchnic extraction of enteral glutamine was comparable in both control and supplemented groups.
Conclusions:
- The pathways for glutamine synthesis and splanchnic utilization are functional in very low birth weight infants by 10 days of life.
- Low-dose glutamine supplementation in a hypocaloric regimen did not significantly alter glutamine or leucine flux.
- These findings suggest glutamine kinetics are robust in this population under the studied conditions.
Abstract:
To quantitate glutamine kinetics in premature infants and determine whether glutamine affects leucine metabolism. 11 very low birth weight (< 1250 g) neonates received 4-h i.v. infusions of L-[2H3]leucine and L-[13C5]glutamine, along with orogastric infusion of L-[I-13C]leucine and L-[I-13C]glutamine on the 10th d of life and in the fed state. Patients were receiving parenteral nutrition and were randomized to receive either hypocaloric, enteral preterm formula alone (controls; n = 5), or glutamine (0.2 g.kg-1.d-1 on the day of the study) supplemented formula (GL.n; n = 6). The rates of appearance (Ra) of leucine and glutamine, and their rates of splanchnic extraction were determined from isotopic enrichments in plasma at steady state. Leucine release from protein breakdown did not differ between groups (123 +/- 51 versus 162 +/- 94 mumol.kg-1h-1 in the controls and GLN group, respectively). Glutamine de novo synthesis accounted for > 80% of overall glutamine Ra, and was similar in both groups (626 +/- 177 versus 525 +/- 86 mumol.kg-1.h-1; NS); 46 +/- 16% and 53 +/- 31% of the enteral glutamine underwent first-pass splanchnic extraction in the controls and GLN group, respectively. These findings indicate that the pathways of glutamine de novo synthesis and glutamine utilization in the splanchnic bed are functional in very low birth weight humans by the 10th d of life. Glutamine supplementation provided at low doses on a hypocaloric regimen results in no apparent differences in flux of glutamine or leucine.