Common and different tissue factors in right atrial tissue from patients with and without atrial fibrillation

Atrial fibrillation is the most common cardiac arrhythmia, and is associated with increased morbidity and mortality. However, the options for preventative therapies have been disappointing. In this study, we sought to evaluate the difference of distribution of tissue and inflammatory markers in right atrial tissue from patients with and without atrial fibrillation. During elective cardiac surgery, right atrial tissue fragments were taken from seven patients with paroxysmal, persistent or permanent atrial fibrillation and 30 patients without atrial fibrillation. Tissue for routine light-microscopical examination were stained with haematoxylin and eosin and processed for apoptosis, protein-gene peptide 9.5 (PGP 9.5), atrial natriuretic peptide (ANUP), vascular endothelial growth factor (VEGF), chromogranin A (ChgA), endothelin (ET-1), interleukin 1α and 10 (Il-1α and Il-10) and β defensins 2, and 3 (βD2 and βD3) by means of biotin-streptavidin immunohistochemistry. For the quantification of structures, the semiquantitative counting method was used. The distribution of βD2-positive endotheliocytes was significantly higher in patients with atrial fibrillation compared to patients without atrial fibrillation (p 0.041). Although the difference was not statistically significant, we observed more apoptotic cardiomyocytes in the right atrial tissue in patients with atrial fibrillation than in patients without atrial fibrillation. There were no statistically significant differences of distribution of PGP 9.5, ANUP, VEGF, ChgA, ET-1, Il-1α, Il-10 and βD3-positive cells in patients with and without atrial fibrillation. Right atrial tissues from patients with atrial fibrillation are characterized by increased cardiomyocyte apoptosis and release of the antimicrobial peptide βD2.