Mosaic Deficiency in Mitochondrial Oxidative Metabolism Promotes Cardiac Arrhythmia during Aging

Cell Metab. 2015 May 5;21(5):667-77. doi: 10.1016/j.cmet.2015.04.005.


Aging is a progressive decline of body function, during which many tissues accumulate few cells with high levels of deleted mitochondrial DNA (mtDNA), leading to a defect of mitochondrial functions. Whether this mosaic mitochondrial deficiency contributes to organ dysfunction is unknown. To investigate this, we generated mice with an accelerated accumulation of mtDNA deletions in the myocardium, by expressing a dominant-negative mutant mitochondrial helicase. These animals accumulated few randomly distributed cardiomyocytes with compromised mitochondrial function, which led to spontaneous ventricular premature contractions and AV blocks at 18 months. These symptoms were not caused by a general mitochondrial dysfunction in the entire myocardium, and were not observed in mice at 12 months with significantly lower numbers of dysfunctional cells. Therefore, our results suggest that the disposition to arrhythmia typically found in the aged human heart might be due to the random accumulation of mtDNA deletions and the subsequent mosaic respiratory chain deficiency.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging*
  • Animals
  • Arrhythmias, Cardiac / etiology*
  • Arrhythmias, Cardiac / genetics
  • Arrhythmias, Cardiac / metabolism
  • Arrhythmias, Cardiac / pathology
  • Cell Respiration
  • DNA, Mitochondrial / genetics*
  • Electron Transport Complex IV / genetics
  • Electron Transport Complex IV / metabolism
  • Gene Deletion
  • Mice
  • Mitochondria / genetics*
  • Mitochondria / metabolism
  • Mitochondria / pathology
  • Mitochondrial Diseases / complications*
  • Mitochondrial Diseases / genetics*
  • Mitochondrial Diseases / metabolism
  • Mitochondrial Diseases / pathology
  • Myocytes, Cardiac / metabolism
  • Myocytes, Cardiac / pathology
  • Oxygen / metabolism*


  • DNA, Mitochondrial
  • Electron Transport Complex IV
  • Oxygen