Lactobacillus rhamnosus GG protects against atherosclerosis by improving ketone body synthesis

Atherosclerosis (AS) is a major cause of death and morbidity worldwide. There is an increasing amount of evidence that the gut microbiota plays an important role in disorders associated with lipid metabolism, such as AS, and alterations in the composition of the gut microbiota and its metabolic potential have been identified as contributing factors in the development of AS. Recently, probiotics have attracted great interest for their excellent cholesterol-lowering ability, their capacity to improve vascular endothelial function, and their participation in the remodeling of the intestinal flora to prevent AS. The incidental findings of our other study suggest that probiotic Lactobacillus rhamnosus GG may be associated with slowing the progression of AS. Thus, we delivered strain GG into mice by oral feeding and found that strain GG could effectively inhibit AS plaque generation. We analyzed the differences in gut microbiota composition and the peripheral blood metabolome in mice after oral feeding of strain GG by 16S DNA sequencing and untargeted metabolomics, respectively. The results showed that strain GG changed the composition of the gut microbiota in mice fed a high-fat diet; elevated the abundance of beneficial bacteria, such as Bilophila and Alistipes, and decreased the abundance of harmful bacteria, such as Deltaproteobacteria. The results of enrichment analysis of the gut microbiota and the peripheral blood metabolome both indicated that the antiatherosclerotic effect of strain GG might be associated with the biosynthesis pathway of ketone bodies. In addition, strain GG attenuated endothelial injury and elevated peripheral blood ketone body content in mice but did not significantly affect low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) content. In conclusion, our study provides new evidence that strain GG slows the progression of AS, which may be associated with its improvement of the gut microbiome and peripheral blood metabolome, its ability to increase the abundance of beneficial bacteria, and its participation in unsaturated fatty acid and ketone body synthesis and degradation. KEY POINTS: • L. rhamnosus GG attenuated endothelial injury and atherosclerotic plaque formation • L. rhamnosus GG elevated the abundance of beneficial bacteria • L. rhamnosus GG elevated peripheral blood ketone body content in mice.