Dysregulation of amino acids is closely linked to the initiation and progression of sarcopenia. We summarized recent advancements in the studies of amino acid profiles in sarcopenia and systematically presented the clinical significance of amino acid flux in sarcopenia.

We systematically searched in MEDLINE, EMBASE, and Cochrane library from inception to June 1, 2021 to capture all studies examining metabolomics of sarcopenia. We used the following keywords: sarcopenia, metabonomics, metabolomics, amino acid profile, and mass spectrometry. Original articles comparing amino acid patterns between persons with and without sarcopenia were included. Two independent investigators independently completed title and abstract screening, data extraction, and quality evaluation. We used a random effects model to examine the association between amino acids levels and sarcopenia. Sensitivity analyses restricted the analyses to studies in which muscle mass was measured by bioelectrical impedance analysis. Study quality was evaluated according to the Agency for Healthcare Research and Quality (AHRQ) checklist.

The systematic research yielded six eligible articles, comprising 1,120 participants. Five studies used muscle mass in combination with physical performance and/or muscle strength as the criteria to diagnose sarcopenia, while one study used muscle mass as a diagnostic criterion alone. We found that the concentrations of branched-chain amino acids leucine (standardized mean difference [SMD] -1.249; 95% confidence interval [CI]: -2.275, -0.223, P = 0.02, I² = 97.7%), isoleucine (SMD -1.077; 95% CI: -2.106, -0.049, P = 0.04, I² = 97.8%), and aromatic amino acid tryptophan (SMD -0.923; 95% CI: -1.580, -0.265, P = 0.01, I² = 89.9%) were significantly reduced in individuals with sarcopenia. Study results were robust in sensitivity analysis.

The homeostasis of amino acids is critical to maintaining muscle health. The profiles of amino acids might be useful biomarkers for the characterization of sarcopenia. Future studies are warranted to study the clinical significance of amino acids in the diagnosis and treatment of sarcopenia.

氨基酸失调与肌肉减少症的发生和发展密切相关。我们总结了肌肉减少症氨基酸谱研究的最新进展，并系统地介绍了氨基酸通量在肌肉减少症中的临床意义。

我们在 MEDLINE、EMBASE 和 Cochrane 图书馆中系统检索了从成立到 2021 年 6 月 1 日的所有研究，以获取所有检查肌肉减少症代谢组学的研究。我们使用了以下关键词：肌肉减少症、代谢组学、代谢组学、氨基酸谱和质谱。包括比较患有和未患有肌肉减少症的人之间的氨基酸模式的原始文章。两名独立研究者独立完成标题和摘要筛选、数据提取和质量评估。我们使用随机效应模型来检查氨基酸水平与肌肉减少症之间的关联。敏感性分析将分析限制在通过生物电阻抗分析测量肌肉质量的研究。研究质量根据医疗保健研究和质量机构 (AHRQ) 清单进行评估。

系统研究产生了六篇符合条件的文章，包括 1,120 名参与者。五项研究将肌肉质量与身体表现和/或肌肉力量相结合作为诊断肌肉减少症的标准，而一项研究仅使用肌肉质量作为诊断标准。我们发现支链氨基酸亮氨酸的浓度（标准化平均差 [S​​MD] -1.249；95% 置信区间 [CI]：-2.275，-0.223，磷= 0.02, I ² = 97.7%), 异亮氨酸 (SMD -1.077; 95% CI: -2.106, -0.049,磷= 0.04, I ² = 97.8%) 和芳香族氨基酸色氨酸 (SMD -0.923; 95% CI: -1.580, -0.265,磷= 0.01, I ² = 89.9%) 在患有肌肉减少症的个体中显着降低。研究结果在敏感性分析中是稳健的。

氨基酸的稳态对于维持肌肉健康至关重要。氨基酸谱可能是表征肌肉减少症的有用生物标志物。有必要进一步研究氨基酸在肌肉减少症诊断和治疗中的临床意义。