1H NMR-based metabolomic analysis of urine from term and preterm neonates

Background: Metabolomics is a general approach to determining a picture of the current metabolic status of an organism by measuring hundreds or thousands of metabolites simultaneously in an intact tissue or biofluid. Aim: To analyze urinary metabolic profile in term and preterm infants in order to identify metabolic patterns associated with different gestational ages. Methods: Twenty-six healthy term infants (gestational age = 39.7 ± 0.8 wks; birth weight = 3292 ± 364 g) and 41 preterm infants (gestational age = 32.0 ± 3.0 wks; birth weight = 1830 ± 758 g) were prospectively enrolled. For each patient, a urine sample was collected non-invasively in the first 12 hours of life. The samples were stored frozen until analysis by Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy. Data from NMR spectra of urine samples were statistically analyzed by using Principal Components Analysis and Partial Least Squares-Discriminate Analysis (SIMCA software). Results: The multivariate statistical analysis of spectral data identifies different classes of neonates that were characterized by different metabolic patterns. Term infants differed significantly from preterm infants. Preterm infants of 23-32 weeks' gestation differed significantly from those of 33-36 weeks' gestation. Metabolites discriminating between groups were hyppurate, tryptophane, phenylalanine, malate, tyrosine, hydroxybutyrate, N-acetyl-glutammate, proline. Conclusions: Metabolomic analysis demonstrated different urinary metabolic profiles in neonates of different gestational ages. This technique may prove to be of use in the diagnosis of pathological conditions, in evaluating drug response, in monitoring therapy or in predicting the onset of renal disorders in later life.