The role of infection in the development of non-valvular atrial fibrillation: up-regulation of Toll-like receptor 2 expression levels on monocytes.
Many studies have suggested that inflammation may participate in the pathogenesis of non-valvular atrial fibrillation (AF). However, it has been unknown by exposure to what the inflammation is caused. Recently, we reported that Toll-like receptor 2 (TLR2) level on monocytes was significantly up-regulated in viral and bacterial infections, but not in non-infectious inflammatory states. Our purpose was to test the hypothesis that expression of TLR2 levels may be up-regulated in patients with non-valvular AF. A total of 48 consecutive patients with non-valvular AF who were hospitalized for catheter ablation were enrolled in this study. TLR2 levels were assayed by using flow-cytometric analysis and compared with volunteers in sinus rhythm (control group, n = 24). Additionally, C-reactive protein (CRP) and interleukin-6 (IL-6) levels were assayed, and the left atrial volume indexes (LAVI) in the non-valvular AF group were measured. The results demonstrated that TLR2 levels in the non-valvular AF group were significantly higher than in the control group (median, 4682 vs. 3866 sites/cell; P < 0.01). Moreover, non-valvular AF patients had significantly higher IL-6 levels than controls. However, there was no significant difference in CRP levels between the two groups. It was observed in 44 AF patients, in whom pulmonary vein isolation was confirmed to be successful, that the LAVI significantly diminished 1 month after ablation (median, 33.6 vs. 29.5 ml/m²; P < 0.001), but not the TLR2 and IL-6 levels. Our results implied that an infectious inflammation may participate in the pathogenesis of non-valvular AF.
Ichiki
Hitoshi
H
Department of Cardiovascular, Respiratory & Metabolic Medicine, Graduate School of Medicine, Kagoshima University, Kagoshima, Japan.
Orihara
Koji
K
Hamasaki
Shuichi
S
Ishida
Sanemasa
S
Oketani
Naoya
N
Iriki
Yasuhisa
Y
Ninomiya
Yuichi
Y
Okui
Hideki
H
Kuwahata
So
S
Fujita
Shoji
S
Matsushita
Takehiko
T
Yoshifuku
Shiro
S
Oba
Ryutaro
R
Hirai
Hiroyuki
H
Nagata
Kinya
K
Tei
Chuwa
C
D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000097:blood* / Q000209:etiology; D002097:C-Reactive Protein / Q000032:analysis; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007239:Infections / Q000150:complications*; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000737:chemistry*; D010446:Peptide Fragments / Q000097:blood; D011347:Procollagen / Q000097:blood; D051195:Toll-Like Receptor 2 / Q000097:blood*; D015854:Up-Regulation
D015850:Interleukin-6; D010446:Peptide Fragments; D011347:Procollagen; D051195:Toll-Like Receptor 2; C041876:procollagen Type III-N-terminal peptide; D002097:C-Reactive Protein