Gut Microbiota Dysbiosis Induced by a High-Fat Diet Increases Susceptibility to Atrial Fibrillation

Background: Obesity is a significant risk factor for atrial fibrillation (AF), and the gut microbiota is closely related to obesity-induced dis-eases. However, whether the gut microbiota is involved in regulating obesity-induced AF has not been studied. This study investigated whether gut microbiota dysbiosis affects obesity-related AF.Methods: Fecal microbes derived from normal diet (ND)-fed and high -fat diet (HD)-fed mice were transplanted into those fed normally. Morphologic, biochemical, functional, histologic, electrophysiological studies, molecular analysis, 16S rRNA gene amplicon sequencing, and RNA-sequencing were performed.Results: Transplantation of the HD gut microbes in ND-maintained(THD) mice led to a significant increase in the susceptibility to AF. Gut microbiota analysis showed a significant increase in Desulfovi-brionaceae, which generated metabolic endotoxemia in THD mice. Transplantation with HD microbes also resulted in significantly increased levels of circulating lipopolysaccharide (LPS), significant disruption in the histologic architecture of the intestinal tissue, and significantly increased proinfiammatory cytokines in the left atrium, indicating that atrial infiammation likely contributed to AF suscepti-bility. RNA-sequencing showed that the THD group had enhanced activation of ferroptosis and TLR4/NF-KB/NLRP3 infiammasome sig-nalling pathway. Inhibiting the ferroptosis or NLRP3 infiammasome signalling pathway significantly improved atrial fibrosis and reduced susceptibility to obesity-related gut dysbiosis-induced AF.Conclusions: This study provides evidence showing an original causal role of gut microbiota dysbiosis in the pathogenesis of obesity-related AF, which showed elevated LPS and dysregulation of atrial pathologic remodelling by activating ferroptosis and the TLR4/NF-KB/NLRP3 infiammasome signalling pathway.