Liet J M, Piloquet H, Marchini J S, Maugère P, Bobin C, Rozé J C, Darmaun D
Division of Neonatology, Hôpital Mère-Enfant, CHU de Nantes, and Centre de Recherche en Nutrition Humaine, France.
Am J Clin Nutr. 1999 Mar;69(3):539-43. doi: 10.1093/ajcn/69.3.539.
Although medium-chain triacylglycerols (MCTs) may be utilized more efficiently than long-chain triacylglycerols (LCTs), their effect on protein metabolism remains controversial.
The aim of the study was to compare the effects of mixed MCT-LCT and pure LCT emulsions on leucine metabolism in preterm infants.
Fourteen preterm [gestational age: 30+/-1 wk; birth weight: 1409+/-78 g (x +/- SE)] neonates were randomly assigned to receive, from the first day of life, either a 50:50 MCT-LCT (mixed MCT group; n = 7) or an LCT (LCT group; n = 7) lipid emulsion as part of an isonitrogenous, isoenergetic total parenteral nutrition program. On the fourth day, infants received intravenous feeding providing 3 g lipid, 15 g glucose, and 3 g amino acids kg(-1) x d(-1) and underwent 1) indirect calorimetry and 2) a primed, 2-h infusion of H13CO3Na to assess the recovery of 13C in breath, immediately followed by 3) a 3-h infusion of L-[1-13C]leucine.
The respiratory quotient tended to be slightly but not significantly higher in the mixed MCT than in the LCT group (0.96+/-0.06 compared with 0.93+/-0.03). We did not detect a significant difference between the mixed MCT and LCT groups with regard to release of leucine from protein breakdown (B; 309+/-40 compared with 257+/-46 micromol x kg(-1) x h(-1)) and nonoxidative leucine disposal (NOLD; 296+/-36 compared with 285+/-49 micromol x kg(-1) x h(-1)). In contrast, leucine oxidation was greater in the mixed MCT than in the LCT group (113+/-10 compared with 67+/-10 micromol x kg(-1) x h(-1); P = 0.007). Net leucine balance (NOLD - B) was less positive in the mixed MCT than in the LCT group (-14+/-9 compared with 28+/-10 micromol x kg(-1) x h(-1); P = 0.011).
Mixed MCTs may not be as effective as LCT-containing emulsions in promoting protein accretion in parenterally fed preterm neonates.
尽管中链三酰甘油（MCTs）的利用效率可能高于长链三酰甘油（LCTs），但其对蛋白质代谢的影响仍存在争议。
本研究旨在比较中链三酰甘油与长链三酰甘油混合乳剂和纯长链三酰甘油乳剂对早产儿亮氨酸代谢的影响。
14例早产儿[胎龄：30±1周；出生体重：1409±78 g（x±SE）]从出生第一天起被随机分配接受50:50中链三酰甘油与长链三酰甘油混合乳剂（混合MCT组；n = 7）或长链三酰甘油乳剂（LCT组；n = 7）作为等氮、等能量全肠外营养方案的一部分。在第4天，婴儿接受静脉喂养，提供3 g/kg·d的脂肪、15 g/kg·d的葡萄糖和3 g/kg·d的氨基酸，并进行1）间接测热法和2）一次首剂量、持续2小时的H13CO3Na输注以评估呼出气体中13C的恢复情况，随后立即进行3）一次持续3小时的L-[1-13C]亮氨酸输注。
混合MCT组的呼吸商略高于LCT组，但差异无统计学意义（分别为0.96±0.06和0.93±0.03）。在蛋白质分解产生亮氨酸的释放量（B；分别为309±40和257±46 μmol·kg-1·h-1）和非氧化亮氨酸处置量（NOLD；分别为296±36和285±49 μmol·kg-1·h-1）方面，混合MCT组与LCT组之间未检测到显著差异。相反，混合MCT组的亮氨酸氧化量高于LCT组（分别为113±10和67±10 μmol·kg-1·h-1；P = 0.007）。混合MCT组的净亮氨酸平衡（NOLD - B）比LCT组的正值小（分别为-14±9和28±10 μmol·kg-1·h-1；P = 0.011）。
在促进经肠外喂养的早产儿蛋白质积累方面，混合中链三酰甘油可能不如含长链三酰甘油的乳剂有效。
