These authors contributed equally to this work.
Mitochondrial functional impairment with aging is exaggerated in isolated mitochondria compared to permeabilized myofibers
Article first published online: 10 NOV 2010
© 2010 The Authors. Aging Cell © 2010 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland
Volume 9, Issue 6, pages 1032–1046, December 2010
How to Cite
Picard, M., Ritchie, D., Wright, K. J., Romestaing, C., Thomas, M. M., Rowan, S. L., Taivassalo, T. and Hepple, R. T. (2010), Mitochondrial functional impairment with aging is exaggerated in isolated mitochondria compared to permeabilized myofibers. Aging Cell, 9: 1032–1046. doi: 10.1111/j.1474-9726.2010.00628.x
- Issue published online: 10 NOV 2010
- Article first published online: 10 NOV 2010
- Accepted manuscript online: 17 SEP 2010 02:16AM EST
- Accepted for publication 29 August 2010
- isolated mitochondria;
- skinned fibers;
- skeletal muscle;
Mitochondria regulate cellular bioenergetics and apoptosis and have been implicated in aging. However, it remains unclear whether age-related loss of muscle mass, known as sarcopenia, is associated with abnormal mitochondrial function. Two technically different approaches have mainly been used to measure mitochondrial function: isolated mitochondria and permeabilized myofiber bundles, but the reliability of these measures in the context of sarcopenia has not been systematically assessed before. A key difference between these approaches is that contrary to isolated mitochondria, permeabilized bundles contain the totality of fiber mitochondria where normal mitochondrial morphology and intracellular interactions are preserved. Using the gastrocnemius muscle from young adult and senescent rats, we show marked effects of aging on three primary indices of mitochondrial function (respiration, H2O2 emission, sensitivity of permeability transition pore to Ca2+) when measured in isolated mitochondria, but to a much lesser degree when measured in permeabilized bundles. Our results clearly demonstrate that mitochondrial isolation procedures typically employed to study aged muscles expose functional impairments not seen in situ. We conclude that aging is associated with more modest changes in mitochondrial function in sarcopenic muscle than suggested previously from isolated organelle studies.