Formononetin mitigates atherosclerosis by reducing trimethylamine N-oxide production through modulation of gut microbiota in LDLR -/- mice

Background: Atherosclerosis is the primary cause of cardiovascular disease. Trimethylamine N-oxide (TMAO) is gut microbiota derived metabolite that contributes to atherogenesis. Formononetin is an isoflavonoid compound that exhibits potential anti-atherogenic properties, but there are no reports of its role in mitigating atherosclerosis by modulating gut microbiota to reduce TMAO production. In this study, formononetin demonstrated anti-atherosclerotic effects by modulating the gut microbiota to reduce TMAO production. Methods: Eight-week-old male LDLR -/- mice were fed on a high-fat diet to induce atherosclerosis, Oil Red O staining was used to assess whether formononetin attenuated atherosclerosis. Fecal transplantation was used to determine whether the anti-atherosclerotic effect of formononetin was mediated by modulation of the gut microbiota. Metagenomic sequencing of the mouse gut microbiota and enzyme-linked immunosorbent assay were used to evaluate whether formononetin reduced TMAO production by modulating gut microbiota. Results: Formononetin significantly reduced the plaque area in the entire aorta and aortic root and increased plaque stability. Fecal transplantation confirmed that the anti-atherosclerotic effect of formononetin was associated with modulation of the gut microbiota. Metagenomic sequencing of the mouse gut microbiota showed that formononetin reduced the relative abundance of Firmicutes, increased the relative abundance of Bifidobacteria, and reduced serum TMAO levels. Moreover, formononetin reduced the expression of the cutC gene in the mouse gut microbiota. Conclusion: Formononetin reduced TMAO production by modulating the gut microbiota, thus contributing to its anti-atherosclerotic effects. Modulation of the gut microbiota to reduce TMAO production may represent one of the mechanisms by which formononetin mitigates atherosclerosis. Graphical abstract: http://links.lww.com/AHM/A211