Noninvasive Assessments of Mitochondrial Capacity in People with Mitochondrial Myopathies
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 t...
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MDPI AG
2024-11-01
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| author | Kevin K. McCully Hannah M. Bossie Fran D. Kendall |
| author_facet | Kevin K. McCully Hannah M. Bossie Fran D. Kendall |
| author_sort | Kevin K. McCully |
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| description | 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 (mVO<sub>2</sub>max) was measured using the rate constant of recovery of oxygen consumption (mVO<sub>2</sub>) 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 mVO<sub>2</sub>max (MITO: 1.4 ± 0.1 min<sup>−1</sup>; AB: 1.5 ± 0.3 min<sup>−1</sup>; <i>p</i> = 0.29), resting mVO<sub>2</sub> (MITO: −0.4 ± 0.2%/min; AB: −0.3 ± 0.1%/min; <i>p</i> = 0.23), or initial post exercise oxygen consumption rates (MITO: 4.3 ± 1.2%/min; AB: 4.4 ± 1.4%/min; <i>p</i> = 0.9). Exercise oxygen desaturation was greater in MITO (39.8 ± 9.7% range) than in AB (28 ± 8.8% range) participants, <i>p</i> = 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 mVO<sub>2</sub>max 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. |
| format | Article |
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| institution | Kabale University |
| issn | 2813-0413 |
| language | English |
| publishDate | 2024-11-01 |
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| series | Muscles |
| spelling | doaj-art-a5de1bfd49b64c34a51b4ed098c969702024-12-27T14:43:19ZengMDPI AGMuscles2813-04132024-11-013439340310.3390/muscles3040033Noninvasive Assessments of Mitochondrial Capacity in People with Mitochondrial MyopathiesKevin K. McCully0Hannah M. Bossie1Fran D. Kendall2Department of Kinesiology, University of Georgia, Athens, GA 30605, USAIntuitive Surgical, Sunnyvale, CA 30086, USAVirtual Medical Practice, Atlanta, GA 30338, USAPeople 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 (mVO<sub>2</sub>max) was measured using the rate constant of recovery of oxygen consumption (mVO<sub>2</sub>) 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 mVO<sub>2</sub>max (MITO: 1.4 ± 0.1 min<sup>−1</sup>; AB: 1.5 ± 0.3 min<sup>−1</sup>; <i>p</i> = 0.29), resting mVO<sub>2</sub> (MITO: −0.4 ± 0.2%/min; AB: −0.3 ± 0.1%/min; <i>p</i> = 0.23), or initial post exercise oxygen consumption rates (MITO: 4.3 ± 1.2%/min; AB: 4.4 ± 1.4%/min; <i>p</i> = 0.9). Exercise oxygen desaturation was greater in MITO (39.8 ± 9.7% range) than in AB (28 ± 8.8% range) participants, <i>p</i> = 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 mVO<sub>2</sub>max 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.https://www.mdpi.com/2813-0413/3/4/33near-infrared spectroscopyNIRSKearns–Sayre syndromeMELASskeletal muscle |
| spellingShingle | Kevin K. McCully Hannah M. Bossie Fran D. Kendall Noninvasive Assessments of Mitochondrial Capacity in People with Mitochondrial Myopathies Muscles near-infrared spectroscopy NIRS Kearns–Sayre syndrome MELAS skeletal muscle |
| title | Noninvasive Assessments of Mitochondrial Capacity in People with Mitochondrial Myopathies |
| title_full | Noninvasive Assessments of Mitochondrial Capacity in People with Mitochondrial Myopathies |
| title_fullStr | Noninvasive Assessments of Mitochondrial Capacity in People with Mitochondrial Myopathies |
| title_full_unstemmed | Noninvasive Assessments of Mitochondrial Capacity in People with Mitochondrial Myopathies |
| title_short | Noninvasive Assessments of Mitochondrial Capacity in People with Mitochondrial Myopathies |
| title_sort | noninvasive assessments of mitochondrial capacity in people with mitochondrial myopathies |
| topic | near-infrared spectroscopy NIRS Kearns–Sayre syndrome MELAS skeletal muscle |
| url | https://www.mdpi.com/2813-0413/3/4/33 |
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