In their research, the team looked at the link between a person's gut health and the development of diseases like high blood pressure, also known as hypertension. The former, in particular, is dependent on the composition of the gut microbiota, a mixture of organisms that populate the gastrointestinal tract. This composition, which plays a role in a person's overall health, is unique to each person – much like his or her genetic makeup. When a person takes an antibiotic to treat an infection, it can kill bacteria indiscriminately, including good bacteria that a person needs for maintaining good health.
This relationship, according to the researchers, explains why "individual hypertensive responses to antibiotics may vary depending on the host and its microbiota."
Two murine models with a genetic predisposition for hypertension were used in the study. Despite having similar tendencies for hypertension, the rats had different gut microbiota. The models were then given the following antibiotics:
Based on the results, Dahl rats –which developed hypertension following a high-salt diet – exhibited elevated levels of systolic blood pressure after being treated with minocycline and neomycin. Having increased levels of systolic blood pressure, in particular, is a risk factor for developing heart attacks and stroke. The Dahl rats also exhibited an increase in diastolic blood pressure after taking minocycline. On the other hand, SHR rats – which developed hypertension independent of dietary salt – did not have significant changes in their blood pressure after antibiotic treatment.
"The host [genetic makeup] plays an important role in how blood pressure will be affected differentially by antibiotic treatment. This highlights the importance of further studies to determine the mechanism behind these different effects," the researchers indicated in their report. "This raises the question of safety in the usage of antibiotics by patients with such modern ailments [as hypertension]."
The effects of the gut microbiota aren't limited to the vascular system. A review published in the journal Hypertension Research established a potentially vital link between the gut microbiota and the overall health of the cardiovascular and renal systems. Researchers from Turkey's Koc University School of Medicine found that the chronic inflammatory processes in the gut microbiota can increase the risk of developing chronic kidney and cardiovascular diseases through multiple immune, metabolic, endocrine, and neurological pathways. In the same manner, a decline in function in the cardiovascular and renal systems can disrupt gut microbiota composition, forming a vicious cycle that damages the two systems further.
Similarly, the researchers suggested developing interventions through diet to stop this cycle. (Related: The health of your gut microbiome could predict your risk of heart disease, researchers find.)
"We can infer that interventions for the gut microbiota through diet and possibly some medications can prevent/stop the vicious cycle between the gut microbiota and the cardiovascular/renal systems, leading to a decrease in chronic cardiovascular and renal diseases," they wrote in their report.