Mitochondria oxidative stress, connexin43 remodeling, and sudden arrhythmic death

Ali A. Sovari, Cody A. Rutledge, Euy Myoung Jeong, Elena Dolmatova, Divya Arasu, Hong Liu, Nooshin Vahdani, Lianzhi Gu, Shadi Zandieh, Lei Xiao, Marcelo G. Bonini, Heather S. Duffy, Samuel C. Dudley*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

77 Scopus citations

Abstract

Background-Previously, we showed that a mouse model (ACE8/8) of cardiac renin-angiotensin system activation has a high rate of spontaneous ventricular tachycardia and sudden cardiac death secondary to a reduction in connexin43 level. Angiotensin-II activation increases reactive oxygen species (ROS) production, and ACE8/8 mice show increased cardiac ROS. We sought to determine the source of ROS and whether ROS played a role in the arrhythmogenesis. Methods and Results-Wild-type and ACE8/8 mice with and without 2 weeks of treatment with L-NIO (NO synthase inhibitor), sepiapterin (precursor of tetrahydrobiopterin), MitoTEMPO (mitochondria-targeted antioxidant), TEMPOL (a general antioxidant), apocynin (nicotinamide adenine dinucleotide phosphate oxidase inhibitor), allopurinol (xanthine oxidase inhibitor), and ACE8/8 crossed with P67 dominant negative mice to inhibit the nicotinamide adenine dinucleotide phosphate oxidase were studied. Western blotting, detection of mitochondrial ROS by MitoSOX Red, electron microscopy, immunohistochemistry, fluorescent dye diffusion technique for functional assessment of connexin43, telemetry monitoring, and in vivo electrophysiology studies were performed. Treatment with MitoTEMPO reduced sudden cardiac death in ACE8/8 mice (from 74% to 18%; P<0.005), decreased spontaneous ventricular premature beats, decreased ventricular tachycardia inducibility (from 90% to 17%; P<0.05), diminished elevated mitochondrial ROS to the control level, prevented structural damage to mitochondria, resulted in 2.6-fold increase in connexin43 level at the gap junctions, and corrected gap junction conduction. None of the other antioxidant therapies prevented ventricular tachycardia and sudden cardiac death in ACE8/8 mice. Conclusions-Mitochondrial oxidative stress plays a central role in angiotensin II-induced gap junction remodeling and arrhythmia. Mitochondria-targeted antioxidants may be effective antiarrhythmic drugs in cases of renin-angiotensin system activation.

Original languageEnglish (US)
Pages (from-to)623-631
Number of pages9
JournalCirculation: Arrhythmia and Electrophysiology
Volume6
Issue number3
DOIs
StatePublished - Jun 2013
Externally publishedYes

Keywords

  • Mitochondria
  • Oxidative stress
  • Sudden cardiac death
  • Ventricular tachycardia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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