Skeletal Muscle Mitochondrial Energetics Are Associated With Maximal Aerobic Capacity and Walking Speed in Older Adults
Skeletal Muscle Mitochondrial Energetics Are Associated With Maximal Aerobic Capacity and Walking Speed in Older Adults
复制标题
DOI：
10.1093/gerona/gls196
复制
发表时间：
2013-04-01
影响因子：
5.1
通讯作者：
Goodpaster, Bret H.
中科院分区：
文献类型：
--
作者：
Coen, Paul M.;Jubrias, Sharon A.;Goodpaster, Bret H.
随着年龄的增长，行走能力降低可能与骨骼肌内氧化能力降低有关。本研究探讨了一组老年人骨骼肌线粒体容量和效率与步行性能之间的关系，37名老年人（平均年龄78岁; 21名男性和16名女性）完成了有氧能力（VO 2峰值）测试和测量超过400米的首选步行速度。最大耦合（状态3; St 3）线粒体呼吸通过高分辨率呼吸测定法在从股外侧肌（n = 22）的经皮活组织检查获得的皂苷透化的肌纤维中测定。用P-31磁共振波谱法测定股外侧肌的最大磷酸化能力（ATP（max））。通过磁共振成像测定股四头肌收缩量。线粒体效率（最大ATP产生/最大O-2消耗）使用每次St 3呼吸的ATP（max）（ATP（max）/St 3）来表征。体外St 3呼吸与体内ATP（max）显著相关（r（2）= .47，p = .004）。四头肌的总氧化能力（St 3 * 四头肌收缩体积）是VO 2峰值的决定因素（r（2）= .33，p = .006）。ATP（max）（r（2）= 0.158，p = 0.03）和VO 2峰值（r（2）= 0.475，p <0.0001）与首选步行速度相关。在多元线性回归模型中加入ATP（max）/St 3和VO 2峰值改善了对首选步行速度的预测（r（2）= 0.647，p <0.0001），表明线粒体效率是首选步行速度的重要决定因素。在一组功能广泛的老年参与者中，较低的线粒体容量和效率都与较慢的步行速度相关。除了有氧能力，线粒体能力和效率降低可能在随着年龄增长而减慢步态速度方面发挥作用。
Lower ambulatory performance with aging may be related to a reduced oxidative capacity within skeletal muscle. This study examined the associations between skeletal muscle mitochondrial capacity and efficiency with walking performance in a group of older adults.Thirty-seven older adults (mean age 78 years; 21 men and 16 women) completed an aerobic capacity (VO2 peak) test and measurement of preferred walking speed over 400 m. Maximal coupled (State 3; St3) mitochondrial respiration was determined by high-resolution respirometry in saponin-permeabilized myofibers obtained from percutanous biopsies of vastus lateralis (n = 22). Maximal phosphorylation capacity (ATP(max)) of vastus lateralis was determined in vivo by P-31 magnetic resonance spectroscopy (n = 30). Quadriceps contractile volume was determined by magnetic resonance imaging. Mitochondrial efficiency (max ATP production/max O-2 consumption) was characterized using ATP(max) per St3 respiration (ATP(max)/St3).In vitro St3 respiration was significantly correlated with in vivo ATP(max) (r(2) = .47, p = .004). Total oxidative capacity of the quadriceps (St3*quadriceps contractile volume) was a determinant of VO2 peak (r(2) = .33, p = .006). ATP(max) (r(2) = .158, p = .03) and VO2 peak (r(2) = .475, p < .0001) were correlated with preferred walking speed. Inclusion of both ATP(max)/St3 and VO2 peak in a multiple linear regression model improved the prediction of preferred walking speed (r(2) = .647, p < .0001), suggesting that mitochondrial efficiency is an important determinant for preferred walking speed.Lower mitochondrial capacity and efficiency were both associated with slower walking speed within a group of older participants with a wide range of function. In addition to aerobic capacity, lower mitochondrial capacity and efficiency likely play roles in slowing gait speed with age.