Ontogeny of methionine utilization and splanchnic uptake in critically ill children.
Ontogeny of methionine utilization and splanchnic uptake in critically ill children.
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危重儿童蛋氨酸利用和内脏摄取的个体发育。
DOI：
10.1152/ajpendo.00396.2009
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Castillo,Leticia
中科院分区：
文献类型：
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作者：
Verbruggen,Sascha;Sy,Jama;Gordon,WilliamE;Hsu,Jean;Wu,Manhong;Chacko,Shaji;Zurakowski,David;Burrin,Douglas;Castillo,Leticia
为了确定危重儿科患者的蛋氨酸内脏吸收和利用率，我们使用了两种动力学模型：血浆蛋氨酸富集和“细胞内”同型半胱氨酸富集。24例患者，8名婴儿，8名儿童和8名青少年，进行了研究。它们同时接受1-[2 H3]甲基蛋氨酸和肠溶-[1- 13 C]蛋氨酸的预充、恒定静脉输注。[13 C]同型半胱氨酸与[13 C]蛋氨酸的比值在婴儿、儿童和青少年分别为1.0 ± 0.15、0.80 ± 0.20和0.66 ± 0.10，婴儿与青少年之间有显著性差异（P< 0.01）。婴儿、儿童和青少年的甲氨蝶呤内脏摄取率分别为63%、45%和36%，婴儿高于青少年（P< 0.01）。婴儿蛋氨酸通量的73%用于非氧化处置，27%用于转硫（P< 0.001）。相反，在青少年中，40%用于非氧化处理，而60%用于转硫化。危重患儿的内脏蛋氨酸吸收率和蛋氨酸利用率存在个体发育性，婴儿期用于合成蛋白质和蛋氨酸衍生物的蛋氨酸利用率较高（P< 0.01），转硫率较低（P< 0.01），而青少年期则相反。血浆模型低估了儿童和青少年中的蛋氨酸动力学，但未低估婴儿中的蛋氨酸动力学，表明婴儿人群中蛋氨酸代谢的稀释程度较低且区室化程度较高。所有患者均处于蛋氨酸负平衡状态，表明这些患者目前的肠内营养支持不足。
To determine the rates of methionine splanchnic uptake and utilization in critically ill pediatric patients we used two kinetic models: the plasma methionine enrichment and the “intracellular” homocysteine enrichment. Twenty four patients, eight infants, eight children, and eight adolescents, were studied. They received simultaneous, primed, constant, intravenous infusions ofl-[2H3]methylmethionine and enterall-[1-13C]methionine. The ratio of [13C]homocysteine to [13C]methionine enrichment was 1.0 ± 0.15, 0.80 ± 0.20, and 0.66 ± 0.10, respectively, for the infants, children, and adolescents, and it was different between the infants and adolescents (P< 0.01). Methionine splanchnic uptake was 63, 45, and 36%, respectively, in the infants, children, and adolescents, and it was higher (P< 0.01) in the infants compared with the adolescents. The infants utilized 73% of methionine flux for nonoxidative disposal, while 27% was used for transulfuration (P< 0.001). Conversely, in the adolescents, 40% was utilized for nonoxidative disposal, while 60% was used for transulfuration. There is ontogeny on the rates of methionine splanchnic uptake and on the fate of methionine utilization in critically ill children, with greater methionine utilization for synthesis of proteins and methionine-derived compounds (P< 0.01) and decreased transulfuration rates in the infants (P< 0.01), while the opposite was observed in the adolescents. The plasma model underestimated methionine kinetics in children and adolescents but not in the infants, suggesting lesser dilution and greater compartmentation of methionine metabolism in the infant population. All patients were in negative methionine balance, indicating that the current enteral nutritional support is inadequate in these patients.