McCully Kevin K, Bossie Hannah M, Kendall Fran D
Department of Kinesiology, University of Georgia, Athens, GA 30605, USA.
Intuitive Surgical, Sunnyvale, CA 30086, USA.
Muscles. 2024 Nov 26;3(4):393-403. doi: 10.3390/muscles3040033.
People affected by mitochondrial myopathies (MITOs) are thought to have impaired skeletal muscle oxygenation. The aims of this study were to measure skeletal muscle mitochondrial capacity in MITO participants and able-bodied (AB) participants and evaluate the influence of muscle-specific endurance training in one MITO participant. Participants (n = 7) with mitochondrial disease and controls (n = 9) were tested (ages 18-54 years). Mitochondrial capacity (mVOmax) was measured using the rate constant of recovery of oxygen consumption (mVO) after exercise in the forearm flexor muscles with near-infrared spectroscopy (NIRS). One MITO participant was tested before and after performing 18 forearm exercise sessions in 30 days. There were no differences between MITO and AB participants in mVOmax (MITO: 1.4 ± 0.1 min; AB: 1.5 ± 0.3 min; = 0.29), resting mVO (MITO: -0.4 ± 0.2%/min; AB: -0.3 ± 0.1%/min; = 0.23), or initial post exercise oxygen consumption rates (MITO: 4.3 ± 1.2%/min; AB: 4.4 ± 1.4%/min; = 0.9). Exercise oxygen desaturation was greater in MITO (39.8 ± 9.7% range) than in AB (28 ± 8.8% range) participants, = 0.02. The MITO participant who trained increased her mitochondrial capacity (58%) and muscle-specific endurance (24%) and had reduced symptoms of muscle fatigue. We found no evidence supporting in vivo impairment of forearm muscle mVOmax in genetically confirmed MITO participants. This is consistent with studies that report increased mitochondrial content, which offsets the decrease in mitochondrial function. Positive muscle adaptations to endurance training appear to be possible in people with MITOs. Characterization of study populations will be important when interpreting the relationship between in vivo mitochondrial capacity and mitochondrial disease.
线粒体肌病（MITOs）患者被认为存在骨骼肌氧合受损的情况。本研究的目的是测量线粒体肌病参与者和健康对照（AB）参与者的骨骼肌线粒体功能，并评估一名线粒体肌病参与者进行肌肉特异性耐力训练的影响。对患有线粒体疾病的参与者（n = 7）和对照组（n = 9）进行了测试（年龄在18 - 54岁之间）。使用近红外光谱（NIRS）在前臂屈肌运动后通过氧消耗恢复速率常数（mVO）来测量线粒体功能（mVOmax）。一名线粒体肌病参与者在30天内进行18次前臂运动前后分别接受了测试。线粒体肌病参与者和健康对照参与者在mVOmax（线粒体肌病组：1.4±0.1分钟；健康对照组：1.5±0.3分钟；P = 0.29）、静息mVO（线粒体肌病组：-0.4±0.2%/分钟；健康对照组：-0.3±0.1%/分钟；P = 0.23）或运动后初始氧消耗率（线粒体肌病组：4.3±1.2%/分钟；健康对照组：4.4±1.4%/分钟；P = 0.9）方面没有差异。线粒体肌病参与者的运动性氧饱和度下降幅度（39.8±9.7%范围）大于健康对照参与者（28±8.8%范围），P = 0.02。接受训练的线粒体肌病参与者线粒体功能提高了（58%），肌肉特异性耐力提高了（24%），且肌肉疲劳症状减轻。我们没有发现证据支持基因确诊的线粒体肌病参与者体内前臂肌肉mVOmax受损。这与报告线粒体含量增加从而抵消线粒体功能下降的研究结果一致。线粒体肌病患者似乎有可能通过耐力训练使肌肉产生积极适应性变化。在解释体内线粒体功能与线粒体疾病之间的关系时，研究人群的特征描述将很重要。
