Department of Geriatrics, Neurosciences, and Orthopaedics, Catholic University of the Sacred Heart, Rome, Italy.
Department of Chemistry, 'Sapienza' University of Rome, Rome, Italy.
J Cachexia Sarcopenia Muscle. 2017 Feb;8(1):69-77. doi: 10.1002/jcsm.12134. Epub 2016 Aug 8.
Chronic inflammation, changes in body composition, and declining physical function are hallmarks of the ageing process. The aim of the present study was to provide a preliminary characterisation of the relationship among these age-related phenomena via multivariate modelling.
Thirty-five old adults (OAs) and 17 young adults (YAs) were enrolled. The volume of skeletal muscle, subcutaneous adipose tissue (SAT), and intermuscular adipose tissue (IMAT) of the thigh was quantified by three-dimensional magnetic resonance imaging. Muscle strength was measured by knee extension strength testing. In OAs, physical performance was further assessed via the Short Physical Performance Battery (SPPB). Multi-block partial least squares-discriminant analysis (PLS-DA) was employed to explore the relationship among inflammatory profiles and functional and imaging parameters. Double cross-validation procedures were used to validate the predictive ability of the PLS-DA model.
The optimal complexity of the PLS-DA model was found to be two latent variables. The proportion of correct classification was 92.3% in calibration (94.1% in YAs and 91.4% in OAs), 84.6% in internal validation (95.3% in YAs and 78.5% in OAs), and 82.6% in external validation (94% in YAs and 76.9% in OAs). Relative to YAs, OAs were characterised by smaller muscle volume, greater IMAT volume, lower muscle strength, and higher levels of myeloperoxidase, P-selectin, soluble intercellular adhesion molecule 1, and vascular cell adhesion molecule 1. Compared with OAs with SPPB >8, those scoring ≤8 were characterised by smaller muscle volume, greater SAT volume, lower muscle strength, and higher levels of interleukin 1 beta, 6, 10, 12, 13, tumour necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor.
Multi-block PLS-DA identified distinct patterns of relationships among circulating cytokines and functional and imaging parameters in persons of different ages and varying levels of physical performance. The longitudinal implementation of such an innovative strategy could allow for the tracking of health status over time, the early detection of deviations in health trajectories, and the monitoring of response to treatments.
慢性炎症、身体成分变化和身体功能下降是衰老过程的特征。本研究的目的是通过多变量建模初步描述这些与年龄相关现象之间的关系。
纳入 35 名老年人（OA）和 17 名年轻人（YA）。通过三维磁共振成像定量大腿的骨骼肌、皮下脂肪组织（SAT）和肌间脂肪组织（IMAT）。通过膝关节伸展力量测试测量肌肉力量。在 OA 中，进一步通过短体适能表现量表（SPPB）评估身体表现。采用多块偏最小二乘判别分析（PLS-DA）探索炎症谱与功能和成像参数之间的关系。采用双交叉验证程序验证 PLS-DA 模型的预测能力。
发现 PLS-DA 模型的最佳复杂度为两个潜在变量。校准中的正确分类比例为 92.3%（YA 为 94.1%，OA 为 91.4%），内部验证为 84.6%（YA 为 95.3%，OA 为 78.5%），外部验证为 82.6%（YA 为 94%，OA 为 76.9%）。与 YA 相比，OA 的肌肉体积较小，IMAT 体积较大，肌肉力量较低，髓过氧化物酶、P-选择素、可溶性细胞间黏附分子 1 和血管细胞黏附分子 1 水平较高。与 SPPB>8 的 OA 相比，SPPB≤8 的 OA 的肌肉体积较小，SAT 体积较大，肌肉力量较低，白细胞介素 1β、6、10、12、13、肿瘤坏死因子α和粒细胞-巨噬细胞集落刺激因子水平较高。
多块 PLS-DA 确定了不同年龄和不同身体表现水平的个体中循环细胞因子与功能和成像参数之间的不同关系模式。这种创新策略的纵向实施可以随着时间的推移跟踪健康状况，早期发现健康轨迹的偏差，并监测对治疗的反应。
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