Reduced early dried blood spot citrulline levels in preterm infants with meconium obstruction of prematurity

•Citrulline were not associated with either gestational age or body measurements.•Citrulline are reduced in preterms with meconium obstruction.•Citrulline may have clinical utility as a predictor of meconium obstruction.

BackgroundCitrulline is a non-protein amino acid synthesized in the enterocytes of the small bowel. Recent studies have reported that plasma citrulline levels correlate with functional enterocyte mass.AimsThis study aimed to determine the normal dried blood spot (DBS) citrulline levels and to determine the existence of a correlation between citrulline levels and meconium obstruction of prematurity (MOP).Study design and subjectsA retrospective cohort study was performed involving 285 infants born at less than 32 weeks gestation who were admitted to the neonatal intensive care unit between Oct 2009 and Aug 2014.Outcome measuresWe analyzed the DBS citrulline levels, which are routinely measured via newborn screening at 7 days following birth, using liquid chromatography-MS/MS. We investigated the relationship between DBS citrulline levels and clinical parameters such as gestational age (GA), body measurements at birth, gender, or the presence or absence of either necrotizing enterocolitis or MOP.ResultsA total of 229 infants with a median GA of 29.6 weeks and a median birth weight of 1160 g were included. DBS citrulline levels were not associated with GA, body measurements at birth or gender. DBS citrulline levels were significantly decreased when patients presented with MOP (p = 0.037).ConclusionsEarly DBS citrulline levels were not associated with either GA or body measurements at birth but were reduced among preterm infants with MOP compared with the control infants. These results may be indicative of abnormal fetal intestinal development and reduced functional enterocyte mass among preterm infants with MOP.