Association of amino acids with common complications of prematurity

BACKGROUND: Tandem mass spectrometry has been proposed as a method of diagnosing or predicting the development of common complex neonatal diseases. Our objective was to identify metabolites associated with common complications of prematurity. METHODS: We performed a retrospective analysis of medical data and metabolite measurements from routine neonatal screening on 689 preterm (<37 wk of gestational age) neonates. RESULTS: We observed higher levels of phenylalanine (PHE) in infants with respiratory distress syndrome (RDS; P = 1.7 x 10(-5)), the only association that was significant after correction for multiple testing. We found suggestive significance (P < 0.001) of higher essential amino acids in infants with patent ductus arteriosus (PDA). Functionality of these findings was explored in the ductus arteriosus (DA) isolated from term and preterm mouse pups. None of the amino acids had a direct vasodilatory effect on the isolated DA. CONCLUSION: We found that newborns with RDS had higher levels of PHE that may be a result of impaired PHE hydroxylase activity. We also detected marginally higher levels of all measured essential amino acids in infants with PDA. We did not find dilation of the mouse ductus for these metabolites, indicating that instead of potentially causing PDA, they are probably serving as markers of catabolism.