Objective: To investigate the urinary metabolic spectrum and pathways in very low birth weight (VLBW) premature infants. Method: A prospective case-control study was conducted to collect and compare the data of VLBW premature infants and full term infants from the Sixth Affiliated Hospital of Sun Yet-Sen University in 2014. Within 24 hours after birth, urine specimens in each group were collected. Metabolites of urine samples including amino acid, fatty acid and organic acid were detected using the urease pre-processing and gas chromatography mass spectrometry (GC-MS) technology. Using the orthogonal partial least squares discriminant analysis (OPLS-DA), the biomarkers and differences between the two groups were found. The online metabolic pathway website was explored and multivariable analysis was conducted to investigate the valuable pathways and biomarkers related to the prematurity. Result: A total of 20 VLBW premature infants were enrolled, among whom 11 were male, 9 were female; and 20 full term infants were enrolled, among whom 9 were male, 11 were female. The urinary metabolites were established and compared between the VLBW premature and term infants. The investigation showed that the following nine pathways were enriched: amino-acyl-tRNA biosynthesis(P=0.000), lysine degradation(P=0.007), fatty acid biosynthesis(P=0.008), pyrimidine metabolism(P=0.014), pantothenate and CoA biosynthesis(P=0.022), valine, leucine and isoleucine biosynthesis(P=0.022), lysine biosynthesis(P=0.031), glycerolipid metabolism(P=0.046), and valine, leucine and isoleucine degradation(P=0.031). Almost all the metabolites decreased except for the glyceric acid exhibiting a higher content in the VLBW premature infant. 12 potential biomarkers were explored with the most significant covariance and correlation, within which stearic acid, palmiticacid, myristic acid, β-amino-isobutyric acid, and uric acid were lower, while myo-inositol, mannitol, glycine, glucose1, glucose2, glyceric acid and N-acetyl-tyrosine were higher in the VLBW premature group compared with the control group. Conclusion: There is a significant difference between the VLBW premature infants and full-term infants in the metabolic state and pathways. The urease pre-processing and GC-MS technology followed by the OPLS-DA and multivariable analysis to investigate VLBW premature infants' urinary metabolites is a valuable method to evaluate the patients' metabolism.
目的： 探讨极低出生体重早产儿尿代谢谱及通路变化。 方法： 采用前瞻性病例对照研究，选择2014年中山大学附属第六医院出生的极低出生体重早产儿为研究对象，选择同期本院出生的健康足月儿为对照(足月儿组)，于出生后24 h内收集尿液标本，经尿素酶预处理-气相色谱质谱联用技术测定尿样本中氨基酸、脂肪酸和有机酸等小分子代谢物，应用正交偏最小二乘判别分析(OPLS-DA)寻找两组间的差异和生物标志物，结合代谢通路在线网站完成代谢通路富集和重要靶标物质筛选。 结果： 共纳入极低出生体重早产儿组20例，其中男11例、女9例，出生体重(1 240±136) g ；足月儿组20名，其中男9名、女11名，出生体重(3 265±243)g。极低出生体重早产儿组尿代谢谱共富集到氨酰tRNA合成，赖氨酸合成与降解，脂肪酸合成，嘧啶代谢，泛酸盐和辅酶A合成，缬氨酸、亮氨酸和异亮氨酸合成与降解及甘油酯类代谢9条代谢通路，与足月儿组差异均有统计学意义(P＝0.000、0.031、0.007、0.008、0.014、0.022、0.022、0.031、0.046)。通过模式识别分析发现12种协方差和相关性较大的代谢物，即潜在靶标物质，其中硬脂酸、软脂酸、肉豆蔻酸、β-氨基丁酸和尿酸在极低出生体重早产儿组明显降低，肌醇、甘露醇、甘氨酸、葡萄糖1、葡萄糖2、甘油酸和N-乙酰酪氨酸7个物质呈上调变化。 结论： 极低出生体重早产儿和足月儿尿代谢谱和通路具有显著差异，基于尿素酶预处理-气相色谱质谱联用技术结合通路富集及多变量数据分析的代谢组方法可为评估新生儿营养状态提供科学依据。.
Keywords: Gas chromatography-mass spectrometry; Infant, preterm; Metabonome; Urine.