Microbial taxa more likely to be found in people with dyslipidemia

Before the onset of cardiovascular disease symptoms, people often develop dyslipidemia, or abnormal levels of lipids in the blood. Recent studies suggest that microbes in the gut play an important role in how the body produces, regulates and degrades lipids, but the connection isn't clear. 

This week in Microbiology Spectrum, microbiologists in Seoul advance scientists' understanding of that relationship by identifying microbial taxa more likely to be found in people with dyslipidemia than in people with healthy levels of cholesterol and triglycerides. Notably, they reported a distinct difference in the structure of gut microbial communities between the 2 groups. 

A better understanding of the role of gut microbiota in lipid production and metabolism could point to new interventions or microbiome-based strategies for people at risk for cardiovascular diseases, say the researchers behind the new work. 

Dyslipidemia is common and often clinically silent. Studying microbial alterations at this stage provides insight into biological shifts that may occur before clinical cardiovascular disease manifests." 

Han-Na Kim, Ph.D, geneticist and study leader, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul

Kim and her colleagues compared fecal and blood samples from 1,384 participants, 895 of whom had dyslipidemia. Participants were categorized as having dyslipidemia if blood tests showed abnormally high levels of triglycerides, total cholesterol or low-density cholesterol, or low levels of high-density cholesterol-often described as the "good" kind of cholesterol.

The researchers used shotgun metagenomic sequencing to identify bacterial taxa and infer metabolic pathways from microbial genes. They also used this approach to study the resistome-the collection of genetic variations connected to antimicrobial resistance-but did not observe statistically significant differences between the 2 groups.

Their results revealed higher levels of Bacteroides caccae among participants with dyslipidemia. The researchers noted that this bacterium has been associated in prior studies with inflammatory and metabolic processes. In people not diagnosed with dyslipidemia, the researchers also found a higher prevalence of Coprococcus eutactus and Coprococcus catus, bacteria that produce short-chain fatty acids, which in previous studies have shown anti-inflammatory effects, among other health benefits.

"Dyslipidemia appears to be associated with a reduction in bacteria linked to metabolic stability and an enrichment of taxa that may reflect altered lipid and inflammatory states," Kim said. However, she noted that rather than identifying individual bacteria as therapeutic species, the findings, more importantly, point to the need for an overall ecological balance of the gut microbial community. 

"Future translational efforts should focus on restoring functional balance at the community level," she said, "rather than targeting one organism in isolation." Work that builds on these findings, she added, could focus on specific strategies that help people maintain or restore the microbial functions connected to lipid and metabolic balance.