Correlation between plasma levels of arginine and citrulline in preterm and full-term neonates: Therapeutical implications.
BACKGROUND
Preterm neonates exhibit several deficiencies that endanger their lives. Understanding those disturbances will provide tools for the management of preterm neonates. The present work focuses on arginine and citrulline which has been flagged among the biochemical landmarks of prematurity.


METHODS
We examined blood samples of preterm newborns as compared with mature neonates to determine the levels of arginine and citrulline by capillary zone electrophoresis with laser induced fluorescence detection (CZE-LIFD).


RESULTS
Significantly lower levels of arginine and citrulline were found in preterm neonates than in mature neonates (P<.01). Interestingly there was a highly significant correlation between the two amino acids in mature neonates (P<.0001). Such correlation was present in preterm neonates too (P<.01). Pearson coefficient showed that 60% of the citrulline concentration depends on arginine concentration in mature neonates. Only 20% of the citrulline concentration depends on arginine concentration in preterm neonates. Although the ratio arginine/citrulline was lower in preterm neonates than in mature neonates the difference was not statistically significant.


CONCLUSIONS
These results suggest that less arginine is converted to citrulline to form nitric oxide in preterm than in full-term neonates. The result is discussed in terms of the immature enzymatic systems in the preterm neonate.
School of Nutrition, Faculty of Medicine, Universidad of Los Andes, Mérida, Venezuela.
Mike T
MT
Contreras
School of Nutrition, Faculty of Medicine, Universidad of Los Andes, Mérida, Venezuela.
Maria J
MJ
Gallardo
Department of Morphological Sciences, Faculty of Medicine, School of Medicine, University of Los Andes, Mérida, Venezuela.|Department of Physiology, Faculty of Medicine, School of Medicine, University of Los Andes, Mérida, Venezuela.
Luis R
LR
Betancourt
Department of Physiology, Faculty of Medicine, School of Medicine, University of Los Andes, Mérida, Venezuela.
Pedro V
PV
Rada
Center of Biomedical Engineering and Telemedicine, Faculty of Engineering, University of Los Andes, Mérida, Venezuela.
Gerardo A
GA
Ceballos
Department of Physiology, Faculty of Medicine, School of Medicine, University of Los Andes, Mérida, Venezuela.
Luis E
LE
Hernandez
Department of Physiology, Faculty of Medicine, School of Medicine, University of Los Andes, Mérida, Venezuela.
Luis F
LF
Hernandez
D001120:Arginine / Q000097:blood*; D002956:Citrulline / Q000097:blood*; D015331:Cohort Studies; D019075:Electrophoresis, Capillary; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000097:blood / Q000453:epidemiology; D007234:Infant, Premature / Q000097:blood*; D007235:Infant, Premature, Diseases / Q000097:blood* / Q000453:epidemiology*; D008297:Male; D009569:Nitric Oxide; D013050:Spectrometry, Fluorescence
D002956:Citrulline; D009569:Nitric Oxide; D001120:Arginine
amino acids; capillary; electrophoresis; fluorescence; infant; nitric oxide; premature