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Real-time Analyses of Retinol Transport by the Membrane Receptor of Plasma Retinol Binding Protein
Published on: January 28, 2013
Postnatal changes in serum retinol status in very low birth weight infants
R H Mupanemunda1, D S Lee, L J Fraher
1Department of Paediatrics, Lawson Research Institute, St. Joseph's Health Centre, University of Western Ontario, London, Canada.
Insights
Very low birth weight (VLBW) infants often have inadequate retinol levels during the neonatal period, despite supplementation. Further strategies are needed to optimize retinol status in these vulnerable infants.
Area of Science:
- Neonatal nutrition and vitamin metabolism.
- Pediatric pulmonology and chronic lung disease.
- Maternal-fetal health and nutrient transfer.
Background:
- Retinol deficiency is a potential risk factor for chronic lung disease in very low birth weight (VLBW) infants.
- Understanding retinol status in VLBW infants during early infancy is crucial for preventing adverse outcomes.
Purpose of the Study:
- To examine the serum retinol (SR) status in VLBW infants from birth to 6 weeks post-term.
- To compare SR levels in VLBW infants with maternal and term infant SR levels.
- To assess the impact of current retinol supplementation practices on SR status.
Main Methods:
- Serum retinol (SR), retinol-binding protein (RBP), and transthyretin (TTR) concentrations were measured weekly from birth to 8 weeks post-term in preterm infants (<34 weeks gestation).
- Umbilical cord SR levels were compared between preterm and term infants, and with maternal SR levels.
- Longitudinal SR profiles were analyzed in 18 VLBW infants receiving regular retinol supplementation.
Main Results:
- Umbilical cord SR was lower in preterm infants compared to term infants and did not correlate with maternal SR.
- Despite supplementation, VLBW infants showed a decline in SR after birth, reaching a nadir around 5-7 weeks.
- SR levels in VLBW infants returned to normal term cord levels by 4-6 weeks post-term, with similar patterns for RBP and a delayed increase in TTR.
Conclusions:
- Current retinol supplementation protocols are insufficient to maintain adequate SR status in VLBW infants during the neonatal period.
- The observed biphasic pattern of SR suggests challenges in achieving optimal nutrient levels in this population.
- Further research and improved strategies are necessary to enhance retinol status in VLBW infants.
Background:
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'.
Methods:
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.
Results:
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'.
Conclusions:
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.
