A C Longardt1, B Schmiedchen2, J Raila2, F J Schweigert2, M Obladen1, C Bührer1, A Loui1. 1. Department of Neonatology, Charité University Medical Center, Berlin, Germany. 2. Department of Physiology and Pathophysiology, Institute of Nutritional Science, University of Potsdam, Potsdam, Germany.
Abstract
BACKGROUND/ OBJECTIVES: Preterm infants have low vitamin A stores at birth, and parenteral administration of high-dose vitamin A reduces pulmonary morbidity. The aim was to characterize vitamin A transport and status. SUBJECTS/ METHODS: Prospective study of 69 preterm infants (median birth weight 995 g, gestational age 28 weeks), in which 51 received 5000 IU vitamin A three times per week intramuscular (i.m.) for 4 weeks and 18 infants without i.m. vitamin A served as controls. Serum retinol, retinyl palmitate, total retinol-binding protein 4 (RBP4), retinol-unbound RBP4 (apo-RBP4) and transthyretin concentrations were determined at days 3 (D3) and 28 (D28) of life. RESULTS: D3 retinol concentrations were low for the entire group (382 (285/531) nmol/l; median/interquartile range) and unrelated to gestational age. D28 retinol was unchanged in controls (382 (280/471) nmol/l), but increased in the vitamin A group (596 (480/825) nmol/l; P<0.001). A similar pattern was observed for RBP4. The calculated retinol-to-RBP4 ratio rose in vitamin A infants (D3: 0.81 (0.57/0.94), D28: 0.98 (0.77/1.26); P<0.01) but not in controls. In the vitamin A group, the retinol-to-RBP4 ratio was >1 in 15% of all infants on D3 and in 45% of infants on D28, but was ⩽1 in all, but one, controls on D28. CONCLUSIONS: In preterm infants receiving a 4-week course of high-dose i.m. vitamin A, serum retinol concentrations increased by 55%, with molar concentrations of retinol exceeding those of RBP4 in 45% of the infants suggesting transport mechanisms other than RBP4.
BACKGROUND/ OBJECTIVES: Preterm infants have low vitamin A stores at birth, and parenteral administration of high-dose vitamin A reduces pulmonary morbidity. The aim was to characterize vitamin A transport and status. SUBJECTS/ METHODS: Prospective study of 69 preterm infants (median birth weight 995 g, gestational age 28 weeks), in which 51 received 5000 IU vitamin A three times per week intramuscular (i.m.) for 4 weeks and 18 infants without i.m. vitamin A served as controls. Serum retinol, retinyl palmitate, total retinol-binding protein 4 (RBP4), retinol-unbound RBP4 (apo-RBP4) and transthyretin concentrations were determined at days 3 (D3) and 28 (D28) of life. RESULTS: D3 retinol concentrations were low for the entire group (382 (285/531) nmol/l; median/interquartile range) and unrelated to gestational age. D28 retinol was unchanged in controls (382 (280/471) nmol/l), but increased in the vitamin A group (596 (480/825) nmol/l; P<0.001). A similar pattern was observed for RBP4. The calculated retinol-to-RBP4 ratio rose in vitamin Ainfants (D3: 0.81 (0.57/0.94), D28: 0.98 (0.77/1.26); P<0.01) but not in controls. In the vitamin A group, the retinol-to-RBP4 ratio was >1 in 15% of all infants on D3 and in 45% of infants on D28, but was ⩽1 in all, but one, controls on D28. CONCLUSIONS: In preterm infants receiving a 4-week course of high-dose i.m. vitamin A, serum retinol concentrations increased by 55%, with molar concentrations of retinol exceeding those of RBP4 in 45% of the infants suggesting transport mechanisms other than RBP4.
Authors: Helen Mactier; Daphne L McCulloch; Ruth Hamilton; Peter Galloway; Michael S Bradnam; David Young; Timothy Lavy; Lesley Farrell; Lawrence T Weaver Journal: J Pediatr Date: 2012-01-28 Impact factor: 4.406
Authors: J E Tyson; L L Wright; W Oh; K A Kennedy; L Mele; R A Ehrenkranz; B J Stoll; J A Lemons; D K Stevenson; C R Bauer; S B Korones; A A Fanaroff Journal: N Engl J Med Date: 1999-06-24 Impact factor: 91.245