Downregulation of Peroxisome Proliferator‐activated Receptor‐γ Expression in Hypertensive Atrial Fibrillation

Background Numerous evidence has suggested that either hypertension or atrial fibrillation (AF) is associated with systemic inflammation. Peroxisome proliferator‐activated receptor‐γ (PPARγ) has been proved to have anti‐inflammatory effects and is implicated as a molecular pathway involved in many cardiovascular diseases, such as hypertension. The correlation between PPARγ inflammation and AF is still unknown. Methods Using a case‐control study design, 57 patients with hypertensive AF (persistent AF: 32, paroxysmal AF: 25) were included into the study groups. A total of 32 age‐matched patients with hypertension, but without AF were selected as the control group. The expressions of PPARγ, interleukin‐6 (IL‐6), and tumor necrosis factor‐α (TNF‐α) mRNA in monocytes were detected by using a reverse transcription‐polymerase chain reaction (RT‐PCR). Interleukin‐1 (IL‐1) was measured by immunoenzymetric methods. Results The PPARγ mRNA was markedly decreased in the hypertensive AF group as compared with the hypertensive non‐AF group, and it was significantly lower in persistent AF than paroxysmal AF (0.222 ± 0.0702 vs 0.564 ± 0.0436, P <0.01). TNF‐α mRNA, IL‐6 mRNA, and IL‐1 were increased in patients with hypertensive AF compared to the non‐AF group and it was even higher in persistent AF than in paroxysmal AF (0.721 ± 0.0541 vs 0.530 ± 0.0496, 0.567 ± 0.044 vs 0.457 ± 0.0505, 325.61 ± 88.10 vs 190.65 ± 59.38, respectively, P <0.01). TNF‐α, IL‐6, and IL‐1 were in negative correlation with PPARγ, the correlation coefficient was − 0.854, − 0.769, and − 0.702, respectively ( P <0.01). Conclusions In hypertensive patients, increased inflammatory cytokines were associated with increased incidence of AF and atrial remodeling; PPARγ may be involved in the pathogenesis of AF by regulation of inflammation. Copyright © 2009 Wiley Periodicals, Inc.