Vitamin B6 vitamer concentrations in cerebrospinal fluid differ between preterm and term newborn infants.

BACKGROUND AND OBJECTIVE: Vitamin B-6 plays a pivotal role in brain development and functioning. Differences in vitamin B-6 homeostasis between preterm and term newborn infants have been reported. The authors sought to investigate whether B-6 vitamers in cerebrospinal fluid (CSF) of preterm and term newborn infants are different. METHODS: B-6 vitamer concentrations were determined in 69 CSF samples of 36 newborn infants (26 born preterm and 10 born term) by ultra performance liquid chromatography-tandem mass spectrometry. CSF samples, taken from a subcutaneous intraventricular reservoir, were bedside frozen and protected from light. RESULTS: Concentrations of pyridoxal (PL), pyridoxal phosphate (PLP), pyridoxic acid (PA), and pyridoxamine (PM) in preterm newborns (postmenstrual age 30-37 weeks) were at least twice as high as in older newborns (postmenstrual age >= 42 weeks). Pyridoxine and pyridoxamine phosphate concentrations were below limits of quantification in all newborns. In CSF of 2 very preterm newborns (postmenstrual age <30 weeks), significant amounts of pyridoxine were present besides high concentrations of PL, PA, and PM, whereas PLP concentrations were relatively low. B-6 vitamers in CSF were positively correlated, especially PA, PLP, and PL. CONCLUSIONS: In CSF of newborn infants, PL, PLP, PA, and PM are present, and concentrations are strongly dependent on postmenstrual age. Our results indicate that vitamin B-6 homeostasis in brain differs between preterm and term newborns. These results should be taken into account for diagnosis and treatment of epilepsy and vitamin B-6 deficiency in newborn infants. Pediatrics 2012; 130: e191-e198