Carnielli V P, Wattimena D J, Luijendijk I H, Boerlage A, Degenhart H J, Sauer P J
Department of Pediatrics, Erasmus University Rotterdam, The Netherlands.
Pediatr Res. 1996 Jul;40(1):169-74. doi: 10.1203/00006450-199607000-00029.
Infants fed formulas devoid of long-chain polyunsaturated fatty acids (LCP) exhibit low plasma LCP concentrations and have poorer retinal and neurologic development in comparison with their human milk-fed counterparts. It is not known whether the low plasma LCP concentrations result from an impaired biosynthetic capacity, a high need or a low dietary intake. With stable isotope technology and high sensitivity tracer detection using gas chromatography-isotope ratio mass spectrometry we measured the conversion of [13C]linoleic acid (C18:2n-6) and [13C]linolenic acid (C18:3n-3) into their longer chain derivatives in five 1-mo-old formula-fed preterm infants (birth weight 1.17 +/- 0.12.kg and gestational age 28.4 +/- 1.3 wk). Carbon-13-labeled linoleic acid and inolenic were mixed with the formula and administered continuously for 48 h. Both tracers were rapidly incorporated in plasma phospholipids, and their metabolic products including arachidonic acid (C20:4n-6) and docosahexaenoic acid (C22:6n-3) became highly enriched. We demonstrate that the preterm infant is capable of synthesizing LCP from their 18-carbon precursors, and our data do not support the hypothesis that a reduced delta 6 desaturation is a main factor leading to low arachidonic acid and docosahexaenoic acid levels.
与母乳喂养的婴儿相比，喂食不含长链多不饱和脂肪酸（LCP）配方奶粉的婴儿血浆LCP浓度较低，视网膜和神经发育较差。目前尚不清楚血浆LCP浓度低是由于生物合成能力受损、需求高还是饮食摄入量低所致。我们使用气相色谱-同位素比率质谱法的稳定同位素技术和高灵敏度示踪剂检测，测量了5名1月龄配方奶粉喂养的早产儿（出生体重1.17±0.12kg，胎龄28.4±1.3周）中[13C]亚油酸（C18:2n-6）和[13C]亚麻酸（C18:3n-3）向其长链衍生物的转化。将碳-13标记的亚油酸和亚麻酸与配方奶粉混合，并连续给药48小时。两种示踪剂都迅速掺入血浆磷脂中，其代谢产物包括花生四烯酸（C20:4n-6）和二十二碳六烯酸（C22:6n-3）高度富集。我们证明早产儿能够从其18碳前体合成LCP，我们的数据不支持δ6去饱和降低是导致花生四烯酸和二十二碳六烯酸水平低的主要因素这一假设。
