Introduction: Atrial fibrillation (AF) represents one of the most common arrhythmias seen clinically and is associated with a significant increase in morbidity and mortality, yet, current treatment paradigms have proven largely inadequate. One of the main contributors to the pathophysiology of AF is inflammation. Hence, reduction of inflammation associated atrial remodeling represents a novel therapeutic strategy for the treatment of AF. One of the most biologically important groups of oxylipins (oxygenated lipids) is the eicosanoids that are potent modulators of immune responses and are derived from arachidonic acid, linoleic acid among others, which are metabolized through three pathways including the cytochrome P450 (CYP) pathway. The CYP products are major anti-inflammatory metabolites with several cardioprotective effects. Hypothesis: We hypothesize that lipid metabolites may represent a new therapeutic target for AF Methods: In the cross-sectional study, human atrial appendage specimens and blood from informed and consented patients were obtained in accordance with the approved UC Davis IRB protocol. Metabolomic profiling for over 100 metabolites was assessed from the plasma of patients using LC-MS/MS. We used Functional Connectome, an extension of the singular value decomposition for matrices, to determine how the metabolites were functionally related to each other. The underlying mechanisms of AF were determined using an integrated approach with molecular biology, flow cytometry, and electrophysiology. Results: Metabolomic profiling shows a significant difference in several metabolites from the arachidonic and linoleic acid pathways in the cohort with AF compared to patients in NSR. There was a significant increase in oxidative stress, endoplasmic reticulum stress, inflammatory cytokines, nuclear translocation of NF-κB, and the activation of MAPK and TGF-b pathways from patients with AF compared to NSR cohort. Conclusions: The study provides important insights into the functional relatedness of the metabolites from the CYP pathway in patients with AF and reveals the prospect of arachidonic and linoleic acid metabolites being novel therapeutic targets in the treatment of AF.
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