Abstract
Background Increased body mass index (BMI) is often found to be a risk factor for cardiac disease.
However, it is unclear whether BMI also affects the gap junction remodeling process
in atrial fibrillation (AF). The aim of the study was to see if BMI can influence
the connexin43 (Cx43) distribution in patients with sinus rhythm (SR) and AF.
Methods We investigated a total of 51 white Caucasian patients of both gender (mean age:
69 years, 30% diabetes mellitus, ejection fraction [EF] > 50%) with SR or AF, with
either BMI < 27 or ≥ 27 undergoing cardiac surgery for mitral valve repair, aortic
valve repair, or coronary heart disease. We obtained human right atrial tissue for
immunohistochemistry and investigated the CX43-positive polar and lateral membrane
length in the different BMI (BMI < 27, BMI ≥ 27) and rhythm groups (SR or AF).
Results In lean SR patients, Cx43 (BMI < 27) was found mainly at the cell poles while only
2% of the lateral membrane stained positive for Cx43. In obese SR patients (BMI > 27),
6.7 ± 0.7% of the lateral membrane was positive (p < 0.05). In AF generally, there was significantly more lateral Cx43 staining, which
was significantly enhanced in obese AF patients. In lean AF patients, lateral Cx43
positivity increased to 14 ± 1% (p < 0.05), while in BMI > 27 AF patients, this was significantly enhanced to 22 ± 2%
(p < 0.05). The BMI effect was independent from left atrial diameter, EF, and comorbidity.
Conclusions Enhanced BMI is associated with increased remodeling effects of AF on irregular Cx43
distribution.
Keywords
body mass index - atrial fibrillation - remodeling - connexin - gap junctions
