Preservation of skeletal muscle mitochondrial content in older adults: relationship between mitochondria, fibre type and high‐intensity exercise training

摘要

Key points

• Ageing is associated with an upregulation of mitochondrial dynamics proteins mitofusin 2 (Mfn2) and mitochondrial dynamics protein 49 (MiD49) in human skeletal muscle with the increased abundance of Mfn2 being exclusive to type II muscle fibres.
• These changes occur despite a similar content of mitochondria, as measured by COXIV, NDUFA9 and complexes in their native states (Blue Native PAGE).
• Following 12 weeks of high‐intensity training (HIT), older adults exhibit a robust increase in mitochondria content, while there is a decline in Mfn2 in type II fibres.
• We propose that the upregulation of Mfn2 and MiD49 with age may be a protective mechanism to protect against mitochondrial dysfunction, in particularly in type II skeletal muscle fibres, and that exercise may have a unique protective effect negating the need for an increased turnover of mitochondria.