Schmiedchen Bettina, Longardt Ann Carolin, Loui Andrea, Bührer Christoph, Raila Jens, Schweigert Florian J
Department of Physiology and Pathophysiology, Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, 14558, Nuthetal, Germany.
Department of Neonatology, Charité University Medical Center, Berlin, Germany.
Eur J Pediatr. 2016 Mar;175(3):365-72. doi: 10.1007/s00431-015-2647-9. Epub 2015 Oct 16.
Despite high-dose vitamin A supplementation of very low birth weight infants (VLBW, <1500 g), their vitamin A status does not improve substantially. Unknown is the impact of urinary retinol excretion on the serum retinol concentration in these infants. Therefore, the effect of high-dose vitamin A supplementation on the urinary vitamin A excretion in VLBW infants was investigated. Sixty-three VLBW infants were treated with vitamin A (5000 IU intramuscular, 3 times/week for 4 weeks); 38 untreated infants were classified as control group. On days 3 and 28 of life, retinol, retinol-binding protein 4 (RBP4), glomerular filtration rate, proteinuria, and Tamm-Horsfall protein were quantified in urine. On day 3 of life, substantial retinol and RBP4 losses were found in both groups, which significantly decreased until day 28. Notwithstanding, the retinol excretion was higher (P < 0.01) under vitamin A supplementation as compared to infants of the control group. On day 28 of life, the urinary retinol concentrations were predictive for serum retinol concentrations in the vitamin A treated (P < 0.01), but not in the control group (P = 0.570).
High urinary retinol excretion may limit the vitamin A supplementation efficacy in VLBW infants. Advanced age and thus postnatal kidney maturation seems to be an important contributor in the prevention of urinary retinol losses.
尽管对极低出生体重儿（VLBW，<1500克）补充了高剂量维生素A，但他们的维生素A状况并未显著改善。这些婴儿中尿视黄醇排泄对血清视黄醇浓度的影响尚不清楚。因此，研究了高剂量维生素A补充对VLBW婴儿尿维生素A排泄的影响。63名VLBW婴儿接受了维生素A治疗（肌肉注射5000国际单位，每周3次，共4周）；38名未治疗的婴儿被归类为对照组。在出生第3天和第28天，对尿液中的视黄醇、视黄醇结合蛋白4（RBP4）、肾小球滤过率、蛋白尿和Tamm-Horsfall蛋白进行定量。在出生第3天，两组均发现大量视黄醇和RBP4流失，到第28天显著减少。尽管如此，与对照组婴儿相比，补充维生素A组的视黄醇排泄更高（P<0.01）。在出生第28天，维生素A治疗组的尿视黄醇浓度可预测血清视黄醇浓度（P<0.01），但对照组则不然（P=0.570）。
高尿视黄醇排泄可能会限制VLBW婴儿补充维生素A的疗效。月龄增加以及由此带来的出生后肾脏成熟似乎是预防尿视黄醇流失的重要因素。
