INTRODUCTION: Citrulline is a nonessential amino acid that is synthesized almost exclusively in the small intestine. In adults and children with short-bowel syndrome, citrulline has served as a reliable index of the remaining small intestine length. Citrulline is also a precursor of arginine, the role of which is crucial for neonatal metabolism and growth.
OBJECTIVE: We sought to determine serial plasma citrulline levels of preterm neonates to assess levels in accordance with age and intestinal maturation, which may serve as a baseline in the event of intestinal abnormalities such as necrotizing enterocolitis (a devastating complication in this age group).
METHODS: We measured serial plasma citrulline levels in 18 clinically stable neonates (gestational age: ≤32 weeks; birth weight: 1000–1750 g) on days 2, 7, 14, 21, and 28. Quantitative analysis of plasma citrulline levels was performed by ion-exchange chromatography with postcolumn derivatization.
RESULTS: In the study population, mean plasma citrulline levels showed a statistically significant increase from 19 ± 4 μmol/L on day 2 and 20 ± 4 μmol/L on day 7 to 23 ± 4 μmol/L on day 14, 29 ± 5 μmol/L on day 21, and 31 ± 5 μmol/L on day 28 (P < .01). The route of feeding did not seem to have an affect on plasma levels of citrulline (similar values were obtained from neonates who were fed enterally and parenterally on day 7).
CONCLUSIONS: Citrulline levels in normal preterm neonates seem to be age-related and may serve as reference values, which facilitates the evaluation of compromised intestinal function in preterm neonates with severe gastrointestinal problems.
Submitted by Hariklia Ioannou
- Copyright © 2008 by the American Academy of Pediatrics