At the latest annual meeting of the Society for Neuroscience at the University of Alabama in Birmingham, United States, researchers presented a report showing that gut bacteria live in different regions of the brain. This appears to be the microbiome in the brain.
This discovery is both fascinating and intimidating. There is still no explanation for how the bacteria reached the brain. Nor is it known whether they are healthy or harmful. Experts even believe they can influence mood and perhaps personality.
What is the microbiome?
The microbiome is the set of microorganisms that live in the body. The part that is located in the intestines is also called intestinal flora.
There are about a hundred million different types of bacteria. These in turn consist of more than three million genes. Of all these genes, humans have only a third in common with others. The rest is exclusive to everyone. The microbiome is therefore an important part of personal identity. For example, some of the key features include:
- regulation of the immune system
- nutrient absorption
- control of external pathogens
Any change in the gut flora can cause autoimmune diseases, allergies or infections. A number of scientists have also linked it to Alzheimer’s and Parkinson’s. On the other hand, imbalances in this microbiome can cause:
- the production of endotoxins
- high levels of oxidation
- the accumulation of belly fat
In addition, chronic inflammation also causes cardiovascular disease and diabetes. While there is a widespread fear of microbes and bacteria, the truth is you can’t live without them. Despite the fact that you may not be aware of it, billions of living things live together in your body.
The microbiome in the brain
However, scientists are now beginning to wonder how these bacteria get into the brain. The brain is protected by the blood-brain barrier.
The blood-brain barrier is a system that protects the brain from the ingress of foreign substances. It allows the passage of water, soluble molecules in lipids and certain gases.
It also allows the selective passage of amino acids and other molecules. The bacteria found in the brain largely come from the gut.
They are glial cells that support neurons and astrocytes. They also prevent the entry of neurotoxins and other substances into the brain.
These harmful substances can cause inflammation with very negative and even deadly consequences, if they somehow penetrate the barrier. The interesting thing is that astrocytes seem to be the favorite place for these gut bacteria to live in the brain.
Researchers have stated that the bacteria can travel through nerves in the gut, the blood-brain barrier or the nose. However, the true cause is still unknown. So there is still a lot to explore about this possible brain microbiome.
dr. Rosalinda Roberts and her team from the Department of Psychiatry and Behavioral Neurobiology at the University of Alabama in Birmingham, United States, are responsible for these findings. They studied the brains of 34 people.
Half of them were healthy subjects and the other half suffered from schizophrenia. They also conducted a parallel study with mice to rule out that the bacteria appeared only after death or that an error could occur due to contamination.
In both studies, scientists observed the presence of bacteria in human and mouse brains in non-infectious or traumatic situations.
They found these bacteria in several areas of the brain. Especially in the substantia nigra, hippocampus and prefrontal cortex, and very little in the visual cortex. In addition, none of the brains examined showed inflammation.
These results have opened the door for speculation and new research into the brain microbiome. Currently, the possibility that these microbes are related to behavior, mood, and certain neurological diseases is being considered.
Featured image courtesy of Rosalinda Roberts, Courtney Walker, and Charlene Farmer.