BACKGROUND: Obesity including metabolic syndrome is an independent risk factor of atrial fibrillation (AF). Although hyperleptinemia is usually a characteristic of obese subjects, the relationship with atrial fibrosis and AF is unknown. We tested the hypothesis that high-fat diet (HFD)-induced hyperleptinemia exacerbates atrial fibrosis and AF. METHODS AND RESULTS: Eight-week-old male C57BL/6 (WT) and leptin-deficient ob/ob (Ob) mice were treated with a normal-fat diet (NFD) or 60% HFD. After 8 weeks, transesophageal burst pacing and electrophysiological study using isolated perfused hearts were performed and left atrial (LA) tissues were collected for histological analysis, hydroxyproline assay, and reverse transcription-polymerase chain reaction. HFD treatment increased body weight in both WT and Ob mice compared with NFD (both P < 0.01). In WT-HFD mice, hyperleptinemia was observed as expected. While transesophageal burst pacing invariably induced AF (8/8, 100%) in WT-HFD mice, AF was induced less frequently (1/8, 12.5%) in Ob-HFD mice (P < 0.01). In isolated perfused hearts, the interatrial conduction time was prolonged in WT-HFD mice, but not in Ob-HFD mice (P < 0.05). Masson's trichrome staining and the hydroxyproline assay revealed interstitial LA fibrosis in WT-HFD mice, which was not observed in Ob-HFD mice (P < 0.05). Upregulation of collagen1, collagen3, α-smooth muscle actin, tumor necrosis factor-α, and monocyte chemoattractant protein-1 mRNA levels was noted in WT-HFD mice LA, but attenuated in Ob-HFD mice LA. CONCLUSIONS: Our findings suggest that hyperleptinemia exacerbates HFD-mediated atrial fibrosis and AF. Inhibition of leptin signaling may become a novel therapeutic target to prevent obesity-related AF.
BACKGROUND:Obesity including metabolic syndrome is an independent risk factor of atrial fibrillation (AF). Although hyperleptinemia is usually a characteristic of obese subjects, the relationship with atrial fibrosis and AF is unknown. We tested the hypothesis that high-fat diet (HFD)-induced hyperleptinemia exacerbates atrial fibrosis and AF. METHODS AND RESULTS: Eight-week-old male C57BL/6 (WT) and leptin-deficient ob/ob (Ob) mice were treated with a normal-fat diet (NFD) or 60% HFD. After 8 weeks, transesophageal burst pacing and electrophysiological study using isolated perfused hearts were performed and left atrial (LA) tissues were collected for histological analysis, hydroxyproline assay, and reverse transcription-polymerase chain reaction. HFD treatment increased body weight in both WT and Ob mice compared with NFD (both P < 0.01). In WT-HFD mice, hyperleptinemia was observed as expected. While transesophageal burst pacing invariably induced AF (8/8, 100%) in WT-HFD mice, AF was induced less frequently (1/8, 12.5%) in Ob-HFD mice (P < 0.01). In isolated perfused hearts, the interatrial conduction time was prolonged in WT-HFD mice, but not in Ob-HFD mice (P < 0.05). Masson's trichrome staining and the hydroxyproline assay revealed interstitial LA fibrosis in WT-HFD mice, which was not observed in Ob-HFD mice (P < 0.05). Upregulation of collagen1, collagen3, α-smooth muscle actin, tumor necrosis factor-α, and monocyte chemoattractant protein-1 mRNA levels was noted in WT-HFD mice LA, but attenuated in Ob-HFD mice LA. CONCLUSIONS: Our findings suggest that hyperleptinemia exacerbates HFD-mediated atrial fibrosis and AF. Inhibition of leptin signaling may become a novel therapeutic target to prevent obesity-related AF.
Authors: Rosa M Agra-Bermejo; Carla Cacho-Antonio; Adriana Rozados-Luis; Marinela Couselo-Seijas; Angel L Fernandez; J M Martinez-Cereijo; S B Bravo; Jose R Gonzalez-Juanatey; Sonia Eiras Journal: Front Physiol Date: 2020-06-30 Impact factor: 4.566
Authors: Martin Aguilar; Robert A Rose; Abhijit Takawale; Stanley Nattel; Svetlana Reilly Journal: Cardiovasc Res Date: 2021-06-16 Impact factor: 10.787