The Presence of Streptococcus Species in the Gut Microbiome Correlates with Atherosclerotic Plaque Burden

It is presently possible to cheaply and reliably determine the bacterial populations making up the gut microbiome via 16S rRNA sequencing. This capability is giving rise to great deal of new knowledge regarding the ways in which changes in the gut microbiome affect health. Populations can provoke inflammation, known to drive the onset and progression of many age-related conditions, or generate harmful or helpful metabolites, about which less is known of the interaction with specific aspects of aging. Adjusting the balance of populations in the gut microbiome, particularly to restore a more youthful gut microbiome in older individuals, may prove to be a useful approach to long-term health once the field moves past tinkering with probiotics in their present form to the use of more powerful techniques such as fecal microbiota transplantation.

Researchers have discovered a link between the levels of certain bacteria living in the gut and coronary atherosclerotic plaques. The new study was based on analyses of gut bacteria and cardiac imaging among 8,973 participants aged 50 to 64 without previously known heart disease. They were all participants in the Swedish CArdioPulmonary bioImage Study (SCAPIS). "We found that oral bacteria, especially species from the Streptococcus genus, are associated with increased occurrence of atherosclerotic plaques in the small arteries of the heart when present in the gut flora. Species from the Streptococcus genus are common causes of pneumonia and infections of the throat, skin, and heart valves."

The research team also found that some of the species linked to the build-up of atherosclerotic plaques in heart arteries were linked to the levels of the same species in the mouth. Furthermore, these bacteria were associated with inflammation markers in the blood, even after accounting for differences in diet and medication between the participants who carried the bacteria and those who did not. "We have just started to understand how the human host and the bacterial community in the different compartments of the body affect each other. Our study shows worse cardiovascular health in carriers of streptococci in their gut. We now need to investigate if these bacteria are important players in atherosclerosis development."