TLR2 Was Overexpressed Independent Of IL-6 In Patients With Valvular Atrial Fibrillation

Purpose: Toll-like receptor 2 (TLR2) has recently been proved up-regulation in patients with non-valvular atrial fibrillation (AF), which suggests that inflammation may participate in the pathogenesis of AF. However, the relationship between TLR2 and valvular AF has not been studied. The aim of the present study was to determine whether the pathogenesis and development of AF is associated with up-regulation of TLR2.Methods: Clinical data and right atrial appendage (RAA) specimens were collected from 20 patients with persistent AF (PeAF), 15 patients with paroxysmal AF (PaAF) and 13 patients with no history of AF undergoing valvular replacement. TLR2 expression was analyzed by qRT-PCR and Western blot, and confirmed by immunohistochemistry. IL-6 expression was determined by Western blot.Results: Gene expression and protein content of TLR2 were increased in both AF subgroups, compared with sinus rhythm (SR) group. Between two AF subgroups, PaAF had a higher TLR2 level than PeAF. However, no different content of IL-6 was found among the three groups, and no correlation was found between TLR2 and IL-6 in PeAF patients (r=0.090, p=0.706), PaAF patients (r=0.408, p=0.131) and AF patients (r=-0.301, p=0.079). Immunohistochemical analysis revealed that TLR2 was distributed in RAAs of AF patients and confirmed the results of Western blot.Conclusion: TLR2 was elevated in AF (especially PaAF) patients with valvular heart disease, which further implied an inflammation might participate in the pathogenesis and development of AF.