The Gut Microbiota and Atherosclerosis: The State of the Art and Novel Perspectives

The human gut microbiota is composed of more than 100 trillion microbes. Most communities are dominated by species belonging to the phyla Bacteroidetes, Firmicutes, Actinobacteria, Proteobacteria, and Verrucomicrobia. Microflora-derived short-chain fatty acids play a pivotal role in the framework of insulin resistance, obesity, and metabolic syndrome. They are an important energy source and are involved in several pathways, with proatherogenic and antiatherogenic effects. The increased gut microbiota lipopolysaccharide levels (defined as “metabolic endotoxemia”) induce a state of low-grade inflammation and are involved in atherosclerotic disease through Toll-like receptor 4. Another important inflammatory trigger in gut microbiota–mediated atherosclerotic promotion is trimethylamine N-oxide. On the other hand, protocatechuic acid was found to promote cholesterol efflux from macrophages, showing an antiatherogenic effect. Further studies to clarify specific gut composition involved in cardiometabolic syndrome and atherogenesis are needed for greater use of targeted approaches.