Gut Bacteria Linked to High Blood Pressure and Depression

The microbiome is the genetic material of all the microbes, bacteria, fungi, protozoa and viruses that live on and inside the human body. The number of genes in all the microbes in one person's microbiome is 200 times the number of genes in the human genome.

A study of human gut bacteria, known as the gut microbiome, suggests that high blood pressure with depression may be a completely different disease than high blood pressure without depression. The gut may be targeted someday to prevent, diagnose and selectively treat different forms of high blood pressure with or without depression.

Scientists from the University of Florida College of Medicine (Gainesville, FL, USA) made a study of bacteria in the gut identified differences between people with high blood pressure compared to those with high blood pressure plus depression. They isolated DNA (deoxyribonucleic acid, the carrier of genetic information) from gut bacteria obtained from the stool samples of 105 volunteers. They used a new technique involving artificial-intelligence software to analyze the bacteria, which revealed four distinct types of bacterial genes and signature molecules.

Surprisingly, the investigators discovered unique patterns of bacteria from people with 1) high blood pressure plus depression; 2) high blood pressure without depression; 3) depression with healthy blood pressure; or 4) healthy subjects without depression or high blood pressure. The authors concluded that the results suggest different medical mechanisms of high blood pressure that correlate with signature molecules produced by gut bacteria. These molecules are thought to impact the cardiovascular system, metabolism, hormones and the nervous system.

Bruce R. Stevens, PhD, a Professor of Physiology & Functional Genomics, Medicine and Psychiatry and the lead author of the study, said, “People are 'meta-organisms' made up of roughly equal numbers of human cells and bacteria. Gut bacteria ecology interacts with our bodily physiology and brains, which may steer some people towards developing high blood pressure and depression. We believe we have uncovered new forms of high blood pressure: 'Depressive Hypertension' (high blood pressure with depression), which may be a completely different disease than 'Non-Depressive Hypertension' (high blood pressure without depression), which are each different from 'Non-Hypertensive Depression.” The study was presented at the American Heart Association's Hypertension 2019 Scientific Sessions on September 5, 2019, in New Orleans, LA, USA.

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University of Florida College of Medicine