Elucidating the Causal Dynamics between Inflammatory Proteins and Atrial Fibrillation Risk Through Bidirectional...

Atrial fibrillation (AF), the most common cardiac arrhythmia, is associated with significant morbidity and mortality. Inflammation has been implicated in the pathogenesis of AF, but the causal relationship between specific inflammatory proteins and AF risk is not well established. This study aims to clarify this relationship using a bidirectional two-sample Mendelian Randomization (TSMR) approach.

Employing a bidirectional Mendelian Randomization (MR) method, we analyzed genetic variants as instrumental variables (IVs) to investigate the influence of 91 circulating inflammatory proteins on AF risk. This approach allowed us to assess the potential causal effects of inflammatory proteins on AF and vice versa, thus providing a comprehensive understanding of the bidirectional nature of their relationship.

Seven inflammatory proteins were significantly associated with AF risk. Three proteins increased the risk: Fibroblast Growth Factor 5 (FGF-5) with an odds ratio (OR) of 1.0743 (95% CI: 1.0466-1.1027, p=7.41E-08), Tumor Necrosis Factor (TNF) with an OR of 1.0832 (95% CI: 1.0261-1.1434, p=0.0038), and Interleukin-2 Receptor Subunit Beta (IL-2RB) with an OR of 1.0814 (95% CI: 1.0151-1.1519, p=0.0153). Four proteins showed a protective effect: CD40 Ligand Receptor (CD40) with an OR of 0.9671 (95% CI: 0.9392-0.9959, p=0.0254), Fms-related Tyrosine Kinase 3 Ligand (FIt3L) with an OR of 0.9553 (95% CI: 0.9173-0.9949, p=0.0274), Leukemia Inhibitory Factor Receptor (LIF-R) with an OR of 0.9254 (95% CI: 0.8678- 0.9868, p=0.0181), and Sulfotransferase 1A1 (ST1A1) with an OR of 0.9461 (95% CI: 0.9097-0.9839, p=0.0056). The reverse MR analysis revealed no significant effects of AF on the levels of these inflammatory proteins, suggesting a unidirectional causality from proteins to AF.

This bidirectional MR study provides robust evidence for a causal relationship between specific inflammatory proteins and AF risk. The identified proteins could serve as potential biomarkers for AF risk stratification and targets for therapeutic intervention, offering new insights into the pathophysiology of AF and avenues for future research.