Scientists say that given the place where they can be found, microorganisms can have a great influence on our mental state.
Scientists say it is possible that some intestinal microorganisms form in the part of our body considered more protected: the human brain. And that even the healthiest humans can have them as guests in the brain, reports Science magazine. In their majority they are microorganisms pertaining to three groups of bacteria: Firmicutes, Proteobacteria and Bacteroidetes.
US researchers released their results on Tuesday during the annual meeting of the Society of Neuroscience in San Diego (California, USA). There, the neuroanatomer Rosalinda Roberts from the University of Alabama in Birmingham (United States) showed images of bacteria that apparently penetrate and inhabit cells in the human brain. Researchers still dare not determine whether these bacteria are beneficial or harmful to the brain.
Microbes in all samples
Roberts reported that his team found five-year objects in the form of an unidentified bar in images, high resolution and taken by an electronic microscope, of brain tissue cuts of people who have just died. For years these elements were ignored by specialists, but in 2018 a bacterologist assured the neuroanatomist that they were bacteria.
Roberts's team investigating brain diseases of people suffering from schizophrenia examined the tissues of 34 people, about half of them healthy and half of the people with the disease mentioned earlier and found the presence of microorganisms in all samples.
Preferred areas for brain bacteria
As observed by subsequent observations of scientists, bacteria usually live in star-shaped cells called astrocytes, which interact with neurons. The microbes are grouped in and around the ends of the astrocytes that surround the blood vessels in the blood-brain barrier.
Microorganisms also seem to be more abundant around the long projections of neurons that are involved in a fatty substance called myelin. Roberts can not explain these preferences, but considers the possibility that bacteria be attracted to fat and sugar in these parts of the brain.
Experiments in a while
Roberts thought that intestinal bacteria could leak into the brains through the blood vessels during the hours between the death of a person and the extraction of the brain.
Then he looked at the brains of healthy mice, who were subjected to analysis immediately after being slaughtered.
All the bacteria contain and even more. Subsequently, Roberts observed the brains of germ-free mice that were carefully bred so they were not surrounded by microbial life and found that their brain tissues were completely clean.
Most of the bacteria that host live in the gut. It is possible that microorganisms reach the brain through the blood vessels, through the nerves of the intestine or even through the nose.
The specialist acknowledges that more experiments are still needed to rule out contamination since tissues may be contaminated by air by the microbes left in the surgical instruments during brain extraction.
Deadly dangers or contribution to the immune system
This finding is very important for medicine since in the case of access to brain bacteria and viruses can cause inflammation that threatens life. The possibility that microorganisms play a fundamental role in our state of mental health is also being considered. However, at the moment they have no evidence that these microorganisms cause inflammation.
On the other hand, the psychiatrist of the University of Maryland, Teodor Postolache affirmed with respect to this new discovery that he is not "very surprised that other things can live in the brain," but "if that were the case it would be revolutionary." According to Postolache, if these common intestinal bacteria are a beneficial presence in brain cells, they could play a fundamental role in regulating the immune activity of the brain.