Objectives: To study the characteristics of amino acid metabolism in preterm infants in Guangxi, China.
Methods: A retrospective analysis was performed on the medical data of 30 757 neonates who underwent the screening for inherited metabolic diseases and had negative results in Guangxi Neonatal Disease Screening Center from 2018 to 2020. Among these neonates, there were 28 611 normal full-term infants (control group) and 2 146 preterm infants (preterm birth group). According to gestational age, the preterm infants were further divided into four groups: very preterm (n=209), moderately preterm (n=307), and late preterm group (n=1 630). According to birth weight, they were divided into three groups: very low birth weight group (n=161), low birth weight group (n=1 085), and normal birth weight group (n=900). According to blood collection time, they were divided into three groups: 3-7 days group (n=1 664), 8-14 days group (n=314) and 15-28 days group (n=168). Tandem mass spectrometry was performed to measure the levels of 11 amino acids in dried blood spots, which were then compared between groups.
Results: After adjustment for confounding factors, there were significant differences in the levels of 11 amino acids among different gestational age groups (P<0.05), and significant differences were observed in the levels of the 11 amino acids between the control group and the various preterm groups (except for citrulline and methionine in the late preterm group). There were significant differences in the levels of 11 amino acids among different birth weight groups (P<0.05). Except for ornithine, there were significant differences in the levels of other amino acids among the different blood collection time groups (P<0.05).
Conclusions: Gestational age, birth weight and blood collection time all affect amino acid metabolism in preterm infants in Guangxi, China. This provides a basis for the laboratory to establish the reference standard and clinical interpretation of blood amino acid levels in preterm infants, and to improve the nutritional metabolism of preterm infants.
目的: 探讨广西地区早产儿的氨基酸代谢变化特点。方法: 回顾性收集2018~2020年于广西新生儿疾病筛查中心进行遗传代谢病筛查且检测结果为阴性的30 757例新生儿的临床资料，其中28 611例正常足月儿为正常对照组。早产儿2 146例，根据胎龄分为极早产组（n=209）、中期早产组（n=307）、晚期早产组（n=1 630）；根据出生体重分为极低出生体重组（n=161）、低出生体重组（n=1 085）、正常出生体重组（n=900）；根据出生后采血时间分为3~7 d组（n=1 664）、8~14 d组（n=314）、15~28 d组（n=168）。采用串联质谱法检测新生儿干血斑中11种氨基酸水平，并分析其在各组中的水平差异。结果: 在控制了相关混杂因素后，按胎龄分组，各组间11种氨基酸水平差异均有统计学意义（P<0.05），与正常对照组比较，晚期早产组除瓜氨酸、蛋氨酸外，其余氨基酸水平差异均有统计学意义（P<0.05）；按出生体重分组，各组间11种氨基酸水平差异均有统计学意义（P<0.05）；按采血时间分组，除鸟氨酸外其余氨基酸在各组间水平差异均有统计学意义（P<0.05）。结论: 广西地区早产儿体内氨基酸在不同胎龄、出生体重和采血日龄呈现不同的代谢差异，为实验室建立早产儿血氨基酸水平参考标准和临床判读，以及改善早产儿营养代谢状况提供了科学依据。.
Keywords: Amino acid; Guangxi; Metabolism; Preterm infant.