Rimbert Virginie, Boirie Yves, Bedu Mario, Hocquette Jean-François, Ritz Patrick, Morio Béatrice
Protein and Energy Metabolism Research Unit, Auvergne University, Human Nutrition Research Centre of Auvergne, Clermont-Ferrand, France.
FASEB J. 2004 Apr;18(6):737-9. doi: 10.1096/fj.03-1104fje. Epub 2004 Feb 20.
The study aimed at determining whether aging and/or sedentariness impairs muscle fat oxidative capacity (OXFA) and whether this was associated with increased risk to develop insulin resistance. We first examined muscle mitochondrial functions, OXFA and insulin sensitivity (ISI; evaluated during an oral glucose tolerance test) in a cross-sectional study with 32 sedentary (S) and endurance-trained (T), young (Y) and elderly (E) men (24.2+/-2.6 vs. 66.6+/-3.2 yr). As for mitochondrial functions, OXFA was higher in T than in S but similar between age groups (SY 41.8+/-11.3, TY 68.0+/-17.7, SE 40.1+/-14.1, TE 73.1+/-20.1 palmitate x min(-1) x g wet tissue(-1); activity P<0.0001, age P=NS, activity x age P=NS). Similar results were obtained with ISI (SY 6.2+/-2.2, TY 11.4+/-4.4, SE 5.9+/-1.5, TE 11.0+/-3.5, activity P<0.001, age P=NS, activity x age P=NS). Stepwise regression showed that, among body composition, VO2max and muscle biochemical characteristics, OXFA was the main predictor of ISI (r=0.60, P<0.001). We subsequently showed in eight sedentary elderly subjects (63.5+/-3.3 yr) that OXFA and insulin sensitivity (measured using insulin clamp) improved in parallel after 8 weeks of endurance training (r=0.79, P<0.01). We concluded that mitochondrial functions, OXFA and ISI, are not impaired by age but by physical inactivity and are closely correlated.
该研究旨在确定衰老和/或久坐是否会损害肌肉脂肪氧化能力（OXFA），以及这是否与发生胰岛素抵抗的风险增加有关。在一项横断面研究中，我们首先检测了32名久坐（S）和耐力训练（T）的年轻（Y）和老年（E）男性（24.2±2.6岁对66.6±3.2岁）的肌肉线粒体功能、OXFA和胰岛素敏感性（ISI；在口服葡萄糖耐量试验期间评估）。至于线粒体功能，T组的OXFA高于S组，但年龄组之间相似（SY组41.8±11.3，TY组68.0±17.7，SE组40.1±14.1，TE组73.1±20.1棕榈酸酯×分钟-1×克湿组织-1；活动P<0.0001，年龄P=无显著性差异，活动×年龄P=无显著性差异）。ISI也得到了类似的结果（SY组6.2±2.2，TY组11.4±4.4，SE组5.9±1.5，TE组11.0±3.5，活动P<0.001，年龄P=无显著性差异，活动×年龄P=无显著性差异）。逐步回归显示，在身体成分、最大摄氧量和肌肉生化特征中，OXFA是ISI的主要预测因子（r=0.60，P<0.001）。我们随后在8名久坐的老年受试者（63.5±3.3岁）中发现，经过8周的耐力训练后，OXFA和胰岛素敏感性（使用胰岛素钳夹测量）平行改善（r=0.79，P<0.01）。我们得出结论，线粒体功能、OXFA和ISI不受年龄影响，而是受身体不活动的影响，并且它们密切相关。
