Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands.
J Am Geriatr Soc. 2010 Nov;58(11):2069-75. doi: 10.1111/j.1532-5415.2010.03150.x.
To investigate the relationship between skeletal muscle fiber type-specific characteristics, circulating hormone concentrations, and skeletal muscle mass and strength in older men.
Cross-sectional analyses.
University research center.
Forty-one community dwelling elderly men (≥ 65).
Leg strength (1-repetition maximum, 1RM) and whole-body and limb muscle mass were determined, and muscle fiber type composition, cross-sectional area (CSA), myonuclear content, and satellite cell (SC) content were assessed in skeletal muscle biopsy samples. In addition, blood samples were collected to determine serum testosterone, sex hormone-binding globulin, insulinlike growth factor (IGF)-1, and IGF binding protein-3 concentrations.
Muscle mass correlated with muscle strength (0.41 ≤ correlation coefficient (r) ≤ 0.72; P < .01). Muscle fiber CSA, myonuclear content, and SC content were significantly lower in type II than in type I muscle fibers. Myonuclear and SC content were positively correlated with muscle fiber CSA. Furthermore, greater muscle fiber CSA (type I and II) was associated with greater thigh muscle area and muscle strength (0.30 ≤ r ≤ 0.45; P < .05). Testosterone concentration was positively correlated with muscle mass and muscle fiber CSA. Regression analysis showed that SC content, myonuclear content, and testosterone concentration are predictive of muscle fiber CSA. Furthermore, muscle mass and type II muscle fiber CSA are predictive of muscle strength.
Skeletal muscle mass and strength in elderly men are positively correlated with muscle fiber type-specific CSA, myonuclear content, and SC content. These findings support the assumption that a decline in SC content plays an important role in age-related decline in muscle mass and strength.
研究老年男性骨骼肌纤维类型特异性特征、循环激素浓度与骨骼肌质量和力量之间的关系。
横断面分析。
大学研究中心。
41 名居住在社区的老年男性（≥65 岁）。
腿部力量（1 次重复最大值，1RM）和全身及肢体肌肉质量，并评估骨骼肌活检样本中的肌肉纤维类型组成、横截面积（CSA）、核内含量和卫星细胞（SC）含量。此外，采集血样以确定血清睾酮、性激素结合球蛋白、胰岛素样生长因子（IGF）-1 和 IGF 结合蛋白-3 浓度。
肌肉质量与肌肉力量呈正相关（0.41≤相关系数（r）≤0.72；P<.01）。Ⅱ型肌纤维的 CSA、核内含量和 SC 含量明显低于Ⅰ型肌纤维。核内含量和 SC 含量与肌纤维 CSA 呈正相关。此外，较大的肌纤维 CSA（Ⅰ型和Ⅱ型）与大腿肌肉面积和肌肉力量更大相关（0.30≤r≤0.45；P<.05）。睾酮浓度与肌肉质量和肌纤维 CSA 呈正相关。回归分析显示，SC 含量、核内含量和睾酮浓度可预测肌纤维 CSA。此外，肌肉质量和Ⅱ型肌纤维 CSA 可预测肌肉力量。
老年男性的骨骼肌质量和力量与肌纤维类型特异性 CSA、核内含量和 SC 含量呈正相关。这些发现支持了这样一种假设，即 SC 含量的下降在与年龄相关的肌肉质量和力量下降中起着重要作用。
