Connexin Gene Transfer Preserves Conduction Velocity and Prevents Atrial Fibrillation
Background—Several lines of evidence have suggested that maintenance of atrial fibrillation (AF) depends on reentrant mechanisms. Maintenance of reentry necessitates a sufficiently short refractory period and/or delayed conduction, and AF has been associated with both alterations. Fibrosis, cellular dysfunction and gap junction protein alterations occur in AF and cause conduction delay. We performed this study to test the hypothesis that gap junction protein overexpression would improve conduction and prevent AF.
Methods and Results—Thirty Yorkshire swine were randomized into 2 groups (sinus rhythm (SR) and AF), and within each group into 3 subgroups: sham-operated control, gene therapy with adenovirus expressing connexin (Cx) 40 and Cx43 (n=5 per subgroup). All animals had epicardial gene painting; the AF group had burst atrial pacing. All animals underwent terminal study 7 days after gene transfer. SR animals had strong transgene expression but no atrial conduction changes. In AF animals, controls had reduced and lateralized Cx43 expression, and Cx43 gene transfer restored expression and cellular location to SR control levels. In the AF group, both Cx40 and Cx43 gene transfer improved conduction and reduced AF relative to controls.
Conclusions—Connexin gene therapy preserved atrial conduction and prevented AF.
- Received July 1, 2011.
- Accepted October 21, 2011.
- Copyright © 2011, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited