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.