Background: Atrial remodeling is considered as the structural basis for the development and sustaining of atrial fibrillation (AF). Osteoprotegerin (OPG)/receptor activator of nuclear factor-κB (RANK)/RANK ligand (RANKL) axis, a key regulatory system in bone metabolism, was recently identified in some cardiovascular disorders for its regulation to myocardial remodeling. We hypothesized that the OPG/RANK/RANKL axis is involved in development and perpetuation of AF by regulating atrial remodeling.
Methods: Biopsies of right atrial appendage and clinical data were collected from sex- and age-matched 24 persistent AF, 24 paroxysmal AF, 24 sinus rhythm (SR) patients undergoing isolated mitral valve surgery and 24 healthy heart donors (normal controls).
Results: A significantly increasing gradient of atrial expression of OPG, RANKL, RANK and RANKL/OPG ratio was identified in normal controls, SR and AF groups. RANKL/OPG ratio was also found significantly higher in paroxysmal AF than persistent AF. Furthermore, atrial expression and activity of the axis was statistically correlated with collagen III/I levels and ratio and the degree of interstitial fibrosis reflected by collagen volume fraction in right atrial appendages.
Conclusions: The present findings suggest a potential role for known mediators of bone homeostasis in the pathogenesis of AF and possibly represent new targets for therapeutic intervention in AF.
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