Mitochondrial Fission and Fusion in Human Diseases

To the Editor: In his review of the diseases in which mitochondrial fission and fusion are implicated, Archer (Dec. 5 issue)(1) does not comment on the implications of mitochondria in the age-related loss of muscle mass (sarcopenia). Impaired mitochondrial biogenesis has been postulated as a key factor in sarcopenia. There is an association between the accumulation of mitochondrial DNA mutations and deficiencies in mitochondrial oxidative phosphorylation in aging skeletal muscle.(2) The expression of the peroxisome-proliferator-activated receptor coactivator 1 (PGC-1), nuclear respiratory factor 1, and cytochrome c is substantially lower in the heart and skeletal muscle of old persons.(3) An ...