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Updated: Feb 14, 2026
Viral Transgene Expression in Rodent Hearts and the Assessment of Cardiac Arrhythmia Risk
Published on: July 27, 2022
Vidarabine, an anti-herpesvirus agent, prevents catecholamine-induced arrhythmias without adverse effect on heart
Kenji Suita1,2, Takayuki Fujita3, Wenqian Cai1
1Cardiovascular Research Institute, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
Abstract:
Sympathetic activation causes clinically important arrhythmias including atrial fibrillation (AF) and ventricular tachyarrhythmia. Although the usefulness of β-adrenergic receptor blockade therapy is widely accepted, its multiple critical side effects often prevent its initiation or continuation. The aim of this study is to determine the advantages of vidarabine, an adenylyl cyclase (AC)-targeted anti-sympathetic agent, as an alternative treatment for arrhythmia. We found that vidarabine, which we identified as a cardiac AC inhibitor, consistently shortens AF duration and reduces the incidence of sympathetic activation-induced ventricular arrhythmias. In atrial and ventricular myocytes, vidarabine inhibits adrenergic receptor stimulation-induced RyR2 phosphorylation, sarcoplasmic reticulum (SR) Ca2+ leakage, and spontaneous Ca2+ release from SR, the last of which has been considered as a potential arrhythmogenic trigger. Moreover, vidarabine also inhibits sympathetic activation-induced reactive oxygen species (ROS) production in cardiac myocytes. The pivotal role of vidarabine's inhibitory effect on ROS production with regard to its anti-arrhythmic property has also been implied in animal studies. In addition, as expected, vidarabine exerts an inhibitory effect on AC function, which is more potent in the heart than elsewhere. Indexes of cardiac function including ejection fraction and heart rate were not affected by a dosage of vidarabine sufficient to exert an anti-arrhythmic effect. These findings suggest that vidarabine inhibits catecholamine-induced AF or ventricular arrhythmia without deteriorating cardiac function in mice.
Insights
Vidarabine effectively treats arrhythmias like atrial fibrillation (AF) and ventricular tachyarrhythmia by inhibiting cardiac adenylyl cyclase (AC). This novel anti-sympathetic agent reduces arrhythmogenic triggers without negatively impacting cardiac function.
Area of Science:
- Cardiology
- Pharmacology
- Molecular Biology
Background:
- Sympathetic activation is a key driver of cardiac arrhythmias, including atrial fibrillation (AF) and ventricular tachyarrhythmia.
- Beta-adrenergic blockade is a standard therapy but is limited by side effects, necessitating alternative treatments.
- Adenylyl cyclase (AC) plays a crucial role in sympathetic signaling pathways implicated in arrhythmia development.
Purpose of the Study:
- To evaluate vidarabine, a novel adenylyl cyclase (AC)-targeted agent, as a potential alternative therapy for sympathetic activation-induced arrhythmias.
- To investigate the anti-arrhythmic mechanisms of vidarabine in cardiac myocytes.
- To assess the effects of vidarabine on cardiac function.
Main Methods:
- In vitro studies using atrial and ventricular myocytes to assess RyR2 phosphorylation, Ca2+ leakage, and spontaneous Ca2+ release.
- Measurement of reactive oxygen species (ROS) production in cardiac myocytes.
- In vivo assessment of vidarabine's efficacy in reducing AF duration and ventricular arrhythmias in a mouse model.
- Evaluation of cardiac function parameters (ejection fraction, heart rate) at therapeutic doses.
Main Results:
- Vidarabine significantly shortened AF duration and reduced the incidence of sympathetic activation-induced ventricular arrhythmias in mice.
- Vidarabine inhibited adrenergic receptor stimulation-induced RyR2 phosphorylation, sarcoplasmic reticulum (SR) Ca2+ leakage, and spontaneous Ca2+ release.
- Vidarabine suppressed sympathetic activation-induced reactive oxygen species (ROS) production in cardiac myocytes.
- Vidarabine demonstrated potent inhibition of cardiac AC activity without adverse effects on ejection fraction or heart rate.
Conclusions:
- Vidarabine acts as a cardiac AC inhibitor, offering a promising therapeutic strategy for managing arrhythmias.
- Its anti-arrhythmic effects are mediated by reducing RyR2 phosphorylation, Ca2+ leakage, and ROS production.
- Vidarabine effectively controls catecholamine-induced arrhythmias without compromising cardiac function in preclinical models.
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