Mupanemunda R H, Lee D S, Fraher L J, Koura I R, Chance G W
Department of Paediatrics, Lawson Research Institute, St. Joseph's Health Centre, University of Western Ontario, London, Canada.
Early Hum Dev. 1994 Jul;38(1):45-54. doi: 10.1016/0378-3782(94)90049-3.
Retinol deficiency may contribute toward the development of chronic lung disease in very low birth weight (VLBW) infants. We examined the retinol status during early infancy in VLBW infants from birth to 6 weeks 'post-term'.
Concentrations of serum retinol (SR) and its carrier proteins, retinol-binding protein (RBP), and transthyretin (TTR), were determined at birth, then weekly for 8 weeks, and at 4-6 weeks 'post-term' in preterm infants of less than 34 weeks gestation. The SR values of umbilical cord blood at birth from the preterm infants were compared to the maternal SR levels as well as to cord SR levels of term infants.
From 24 through 33 weeks gestation, umbilical cord SR at birth was significantly lower than, but did not correlate with, maternal SR (P < 0.01). The cord SR in term infants was also higher than that in preterm infants (262 +/- 68 vs. 183 +/- 67 micrograms/l, P < 0.01). Longitudinal profiles of SR in 18 VLBW infants showed that, despite regular retinol supplementation, there was a decline in SR after birth, reaching a nadir of 128 +/- 40 microgram/l at 5-7 weeks (P < 0.001), followed by an increase toward levels comparable to those seen in full term infants. At follow-up at the corrected age of 4-6 weeks 'post-term', SR levels in VLBW infant (222 +/- 74 micrograms/l) had returned to within the normal range for term cord SR values. The concentrations of RBP also showed a similar biphasic pattern. Transthyretin levels did not change for 8 weeks but increased significantly at 4-6 weeks 'post-term'.
Current practices of retinol supplementation in VLBW infants fail to maintain adequate retinol status in those infants during the neonatal period. Further efforts to improve the retinol status in these infants should be explored.
维生素A缺乏可能导致极低出生体重（VLBW）婴儿慢性肺病的发生。我们研究了VLBW婴儿从出生到足月后6周的早期婴儿期维生素A状态。
测定胎龄小于34周的早产儿出生时、出生后每周8周以及足月后4 - 6周时血清视黄醇（SR）及其载体蛋白视黄醇结合蛋白（RBP）和甲状腺素转运蛋白（TTR）的浓度。将早产儿出生时脐血的SR值与母亲的SR水平以及足月儿的脐血SR水平进行比较。
孕24至33周时，出生时脐血SR显著低于母亲的SR，但两者无相关性（P < 0.01）。足月儿的脐血SR也高于早产儿（262±68 vs. 183±67微克/升，P < 0.01）。18例VLBW婴儿的SR纵向变化曲线显示，尽管定期补充视黄醇，但出生后SR仍下降，在5 - 7周时降至最低点128±40微克/升（P < 0.001），随后上升至与足月儿相当的水平。在足月后4 - 6周的校正年龄随访时，VLBW婴儿的SR水平（222±74微克/升）已恢复到足月儿脐血SR值的正常范围内。RBP的浓度也呈现类似的双相模式。甲状腺素转运蛋白水平在8周内未变化，但在足月后4 - 6周时显著升高。
目前VLBW婴儿补充视黄醇的做法未能在新生儿期维持这些婴儿足够的视黄醇状态。应探索进一步改善这些婴儿视黄醇状态的措施。
