Abstract 13638: Endothelial-Mesenchymal Transition in Human Atrial Fibrillation

Background: Atrial fibrosis is a hallmark of atrial structural remodeling leading to persistence of AF. Although fibroblasts are known to play a major role in atrial fibrosis, their source in the adult atrium is unclear. Here we tested the hypothesis that endothelial cells contribute to fibroblasts accumulation through an endothelial-mesenchymal transition (EndMT) in the human atrium during the progression of AF. Methods and Results: The study group consisted of patients with valvular disease or atrial septal defect who underwent cardiac surgery (n [[Unable to Display Character:  ]]=[[Unable to Display Character:  ]] 38). Atrial tissue was obtained from the left atrial appendage during cardiac surgery. The amount of fibrotic depositions in Masson Trichrome staining of the left atrium (LA) was positively correlated with left atrial dimension (LAD) (y = 0.3004x - 4.395, R2 = 0.3809, P < 0.0001). Also snail and S100A4, indicative of EndMT, in LA quantified by Western blotting showed statistically...