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Macrophage Immunometabolism in Epicardial Adipose Tissue and Obesity-Related Atrial Fibrillation

Xia L, Sun X, Xie L, Liu S, Phanaksri T, Yu Z, Jiang Z, Cao X

Journal of inflammation research, 2026

Abstract

Obesity is a crucial risk factor for atrial fibrillation (AF). The underlying mechanism is partly related to increased epicardial adipose tissue (EAT). EAT directly contacts the adjacent cardiac myocardium where immune and metabolic activities interact. Obesity induces inflammatory and metabolic signals within EAT, which directly influence atrial structure and electrical remodeling. However, the specific immunometabolic mechanisms linking EAT macrophages to atrial arrhythmogenesis remain unclear. We highlight evidence that nutrient excess, hypoxia, oxidative stress, and adipocyte-derived inflammatory signals reprogram glucose, lipid, and amino acid metabolism in EAT macrophages, promoting persistent pro-inflammatory and profibrotic states. Metabolic pathways involving mechanistic target of rapamycin (mTOR)-hypoxia-inducible factor-1α (HIF-1α) signaling, fatty acid and ceramide metabolism, the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome, and metabolic-epigenetic interactions may sustain macrophage activation and amplify local inflammation. These metabolically reprogrammed macrophages subsequently promote atrial fibrosis, electrical heterogeneity, and autonomic dysfunction, while systemic inflammation, insulin resistance, and neurohumoral activation further reinforce the EAT-atrial pathological circuit. Emerging evidence also suggests that EAT characteristics may improve AF risk stratification and that weight loss and metabolic interventions can…

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