BACKGROUND: Metabolic profiling might provide insight into the biologic underpinnings of disability in older adults. METHODS: A targeted mass spectrometry-based platform was used to identify and quantify 45 plasma acylcarnitines in 77 older men with a mean age of 79 years and average body mass index of 28.4 kg/m(2). To control for type I error inherent in a test of multiple analytes, principal components analysis was employed to reduce the acylcarnitines from 45 separate metabolites, into a single "acylcarnitine factor." We then tested for an association between this acylcarnitine factor and multiple indices of physical performance and self-reported function. RESULTS: The acylcarnitine factor accounted for 40% of the total variance in 45 acylcarnitines. Of the metabolites analyzed, those that contributed most to our one-factor solution were even-numbered medium and long-chain species with side chains containing 10-18 carbons (factor loadings >/=0.70). Odd-numbered chain species, in contrast, had factor loadings 0.50 or less. Acylcarnitine factor scores were inversely related to physical performance as measured by the Short Physical Performance Battery total score, two of its three component scores (gait and chair stands Short Physical Performance Battery), and usual and maximal gait speeds (rho = -0.324, -0.348, -0.309, -0.241, and -0.254, respectively; p < .05). CONCLUSIONS: Higher acylcarnitine factor scores were associated with lower levels of objectively measured physical performance in this group of older, largely overweight men. Metabolic profiles of rodents exhibiting lipid-induced mitochondrial dysfunction show a similar phenotypic predominance of medium- and long-chain acylcarnitines.
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机译：背景：代谢谱分析可能提供洞察老年人残疾的生物学基础。方法：基于质谱的靶向平台用于鉴定和定量77名平均年龄为79岁，平均体重指数为28.4 kg / m 2的老年男性中的45种血浆酰基肉碱。为了控制多种分析物测试中固有的I型错误，采用主成分分析将来自45种不同代谢物的酰基肉碱还原为单个“酰基肉碱因子”。然后，我们测试了该酰基肉碱因子与身体表现和自我报告功能的多个指标之间的关联。结果：酰基肉碱因子占45种酰基肉碱总方差的40％。在分析的代谢产物中，对我们的一因素解决方案影响最大的代谢产物是偶数编号的中链和长链物种，其侧链含10-18个碳（因子负载> / = 0.70）。相反，奇数链种的因子负荷为0.50或更小。酰基肉碱因子得分与身体机能成反比，后者由“短期身体机能电池”总得分，其三个组成部分得分中的两个（步态和椅子站立时身体机能电池）以及通常和最大步态速度（rho = -0.324，-分别为0.348，-0.309，-0.241和-0.254; p <.05）。结论：在这个年龄较大，体重超重的男性中，较高的酰基肉碱因子得分与客观测量的较低体能水平相关。啮齿类动物表现出脂质诱导的线粒体功能异常，其代谢谱显示中链和长链酰基肉碱具有相似的表型优势。
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