Kramer Philip A, Coen Paul M, Cawthon Peggy M, Distefano Giovanna, Cummings Steven R, Goodpaster Bret H, Hepple Russell T, Kritchevsky Stephen B, Shankland Eric G, Marcinek David J, Toledo Frederico G S, Duchowny Kate A, Ramos Sofhia V, Harrison Stephanie, Newman Anne B, Molina Anthony J A
medRxiv. 2023 Nov 9:2023.11.08.23298271. doi: 10.1101/2023.11.08.23298271.
The age-related decline in muscle mitochondrial energetics contributes to the loss of mobility in older adults. Women experience a higher prevalence of mobility impairment compared to men, but it is unknown whether sex-specific differences in muscle energetics underlie this disparity. In the Study of Muscle, Mobility and Aging (SOMMA), muscle energetics were characterized using in vivo phosphorus-31 magnetic resonance spectroscopy and high-resolution respirometry of vastus lateralis biopsies in 773 participants (56.4% women, age 70-94 years). A Short Physical Performance Battery score ≤ 8 was used to define lower-extremity mobility impairment. Muscle mitochondrial energetics were lower in women compared to men (e.g. Maximal Complex I&II OXPHOS: Women=55.06 +/- 15.95; Men=65.80 +/- 19.74; p<0.001) and in individuals with mobility impairment compared to those without (e.g., Maximal Complex I&II OXPHOS in women: SPPB≥9=56.59 +/- 16.22; SPPB≤8=47.37 +/- 11.85; p<0.001). Muscle energetics were negatively associated with age only in men (e.g., Maximal ETS capacity: R=-0.15, p=0.02; age/sex interaction, p=0.04), resulting in muscle energetics measures that were significantly lower in women than men in the 70-79 age group but not the 80+ age group. Similarly, the odds of mobility impairment were greater in women than men only in the 70-79 age group (70-79 age group, OR =1.78, 95% CI=1.03, 3.08, p=0.038; 80+ age group, OR =1.05, 95% CI=0.52, 2.15, p=0.89). Accounting for muscle energetics attenuated up to 75% of the greater odds of mobility impairment in women. Women had lower muscle mitochondrial energetics compared to men, which largely explain their greater odds of lower-extremity mobility impairment.
与年龄相关的肌肉线粒体能量代谢下降导致老年人活动能力丧失。与男性相比，女性活动能力受损的患病率更高，但尚不清楚肌肉能量代谢的性别差异是否是造成这种差异的原因。在肌肉、活动能力与衰老研究（SOMMA）中，对773名参与者（56.4%为女性，年龄70 - 94岁）的股外侧肌活检样本，使用体内磷-31磁共振波谱和高分辨率呼吸测定法对肌肉能量代谢进行了表征。采用简短身体机能量表评分≤8来定义下肢活动能力受损。女性的肌肉线粒体能量代谢低于男性（例如，最大复合体I和II氧化磷酸化：女性 = 55.06 +/- 15.95；男性 = 65.80 +/- 19.74；p < 0.001），并且与无活动能力受损的个体相比，有活动能力受损的个体也是如此（例如，女性的最大复合体I和II氧化磷酸化：简短身体机能量表≥9 = 56.59 +/- 16.22；简短身体机能量表≤8 = 47.37 +/- 11.85；p < 0.001）。仅在男性中，肌肉能量代谢与年龄呈负相关（例如，最大电子传递体系能力：R = -0.15，p = 0.02；年龄/性别交互作用，p = 0.04），导致在70 - 79岁年龄组中女性的肌肉能量代谢指标显著低于男性，但在80岁及以上年龄组并非如此。同样，仅在70 - 79岁年龄组中，女性活动能力受损的几率高于男性（70 - 79岁年龄组，比值比 = 1.78，95%置信区间 = 1.03, 3.08，p = 0.038；80岁及以上年龄组，比值比 = 1.05，95%置信区间 = 0.52, 2.15，p = 0.89）。考虑肌肉能量代谢因素后，女性活动能力受损几率较高的情况最多可减轻75%。与男性相比，女性的肌肉线粒体能量代谢较低，这在很大程度上解释了她们下肢活动能力受损几率较高的原因。
