Mitochondria and ageing: Winning and losing in the numbers game

João F. Passos, Thomas Von Zglinicki, Thomas B.L. Kirkwood

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


Mitochondrial dysfunction has long been considered a key mechanism in the ageing process but surprisingly little attention has been paid to the impact of mitochondrial number or density within cells. Recent reports suggest a positive association between mitochondrial density, energy homeostasis and longevity. However, mitochondrial number also determines the number of sites generating reactive oxygen species (ROS) and we suggest that the links between mitochondrial density and ageing are more complex, potentially acting in both directions. The idea that increased density, especially when combined with mitochondrial dysfunction, might accelerate ageing is supported by a negative correlation between mitochondrial density and maximum longevity in an interspecies comparison in mammals, and by evidence for an intimate interconnection between cellular ROS levels, mitochondrial density and cellular ageing. Recent data suggest that retrograde response, which activates mitochondrial biogenesis, accompanies cellular ageing processes. We hypothesise that increased mitochondrial biogenesis, and possibly also impaired degradation and segregation of mitochondria, if occurring as adaptation to pre-existing mitochondrial dysfunction, might aggravate ROS production and thus actively contribute to ageing.

Original languageEnglish (US)
Pages (from-to)908-917
Number of pages10
Issue number9
StatePublished - Sep 2007

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology


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