Bacteroides vulgatus and Bacteroides dorei Reduce Gut Microbial Lipopolysaccharide Production and Inhibit Atherosclerosis

Background: It is increasingly recognized that gut microbiota play a pivotal role in the development of atherosclerotic cardiovascular disease. Previously, we have reported that the abundance of genus Bacteroides is lower in patients with coronary artery disease (CAD) than in patients without CAD with coronary risk factors or in healthy volunteers. However, it remains unclear which and how specific gut bacteria contribute to the progression of atherosclerosis. Methods: We recruited patients with CAD patients and controls without CAD with coronary risk factors. We then compared gut microbial composition using 16S ribosomal RNA gene sequencing in fecal samples to detect species with differential abundance between 2 groups. Subsequently, we used atherosclerosis-prone mice to study the mechanisms underlying the relationship between such species and atherosclerosis. Results: Human fecal 16S ribosomal RNA gene sequencing revealed a significantly lower abundance of Bacteroides vulgatus and Bacteroides dorei in patients with CAD. This significant differential abundance was confirmed by quantitative polymerase chain reaction. Gavage with live B. vulgatus and B. dorei attenuated atherosclerotic lesion formation in atherosclerosis-prone mice, markedly ameliorating endotoxemia followed by decreasing gut microbial lipopolysaccharide production, effectively suppressing proinflammatory immune responses. Furthermore, fecal lipopolysaccharide levels in patients with CAD were significantly higher and negatively correlated with the abundance of B. vulgatus and B. dorei . Conclusions: Our translational research findings identify a previously unknown link between specific gut bacteria and atherosclerosis. Treatment with live B. vulgatus and B. dorei may help prevent CAD. Clinical Trial Registration: URL: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000018051 . Unique identifier: UMIN000015703.