New research out of the Baylor College of Medicine establishes a link between gut microbes and hypertension. That’s right, gut microbes are in the news yet again.
Fact is, alterations to the gut microbiome - termed “dysbiosis” - are already associated with cardiovascular issues. As such, the group proposed that gut microbes transferred from a hypertensive rat to a healthy rat would give that animal hypertension. Conversely, they predicted that transferring gut microbes from the healthy rat to a hypertensive rat would attenuate the hypertension.
To start, the researchers collected cecal contents from wild type or hypertensive rats (spontaneously hypertensive stroke prone rates). They washed and centrifuged the samples and collected the supernatants. The recipient rats were given antibiotics to reduce the number of native gut bacteria.
After transferring gut microbes (supernatants) from hypertensive rats to healthy rats (and vice versa), they recorded blood pressure weekly. Sure enough, blood pressure increased in healthy rats when they were given gut microbes from hypertensive animals! However, blood pressure decreased only somewhat in hypertensive rats that were given healthy gut microbes.
In addition to blood pressure, they also used 16S rRNA sequencing to characterize what types of bacteria predominated in each animal. They observed a significant increase in the ratio of Firmicutes to Bacteroidetes in hypertensive animals.
According to the authors, this study provides “further evidence for the continued study of the microbiota in the development of hypertension in humans and supports a potential role for probiotics as treatment for hypertension. Studies show that supplementing the diet with probiotics (beneficial microorganisms found in the gut) can have modest effects on blood pressure, especially in hypertensive models."
Gut microbes may mediate hypertension through the production of short chain fatty acids. These fatty acids act on G-protein-coupled receptors to regulate blood pressure. The researchers measured the abundance of these fatty acids in the rats, but they did not find significant changes. Dysbiosis of the gut microbiome has also been linked to obesity, insulin resistance, cancer, and changes in mental health.