Preliminary studies found gut bacteria in 34 brains extracted from human cadavers. If confirmed, the discovery can change the paradigms of the immune system of this body.
To the left of a blood vessel, the bacteria are observed, a picture that would be tempting but preliminary evidence of a "brain microbiomy".
This week, at the annual meeting of the Society for Neuroscience in the United States, a poster took all the attention. In that, several microscopic images had been enlarged and the participants mumbled. The pictures showed bacteria that apparently penetrate and live in the cells of healthy human brains.
Researchers at the University of Alabama, who revealed the results, were quite careful about what they were exposed: their tissue samples taken from the body could be infected.
But, if they were not, the find is impressive: This would be the first evidence that bacteria play a role in human brain function. If confirmed, this would be a historical result.
RNA sequencing showed that most bacteria were of three common intestinal fillets: Firmicutes, Proteobacteria and Bacteroidetes.
"This is the week's success," said neuroscientist Ronald McGregor of the University of California, Los Angeles, who was not involved in the work. "It's like a new molecular plant [en el cerebro] with their own needs. … This is amazing. "
And as long as relatively new research appears confirming the most important role of microbes living in the human bowel in various body functions, including our health, our genes and even our feelings, this is particularly surprising as it indicates that this well-being The bacterial kingdom can be linked to a separate "human brain microbiomic" which lies in the head.
To achieve these findings, the team investigated by neuro anatomist Rosalinda Roberts brain samples taken from 34 deceased persons, about half had schizophrenia, and the other half considered healthy before they die.
A few hours after the death, the research team, led by Roberts, removed a thin sheet of 34 people and analyzed them under the lens of powerful high resolution microscope.
In them they saw a few stains that for five years had fascinated one of the members of the team, Dr. Courtney Walker and that only this year a microbiology confirmed that they were bacteria. In each of the brains they found bacteria.
As to how the bacteria came to the brain, the issue is complex. This body is highly protected, partly separated from the blood's content through a network of cells surrounding the blood vessels. Initially, Dr. thought Roberts that they had leaked through the blood vessels in the hours between people's death and brain removal. But later tests with brain mice showed the opposite: Mice research also revealed evidence of brain microbiology in healthy mice, but not in a separate group of seed free mice born in the laboratory.
Thus, Roberts speculation is that the bacteria may have crossed from the blood vessels, through the nerves of the intestines or even through the nose.
Microbiota or surgical contamination?
According to researchers, bacterial density varies according to the area of the brain where they were found, with ample nigra microbes, hippocampus and prefrontal cortex. They were also found in cells called astrocytes, which recently discovered findings have played an important role in how neurons communicate.
And while the team recognizes that it is possible that microbes have entered the brain tissue through any process of surgical contamination During postmortem surgery, the way they spread through the tissue may suggest something else.
The truth is that research leaves more questions than answers. Roberts dares not say much if the microorganisms are useful or harmful. "He did not see signs of inflammation indicating that they caused injury, but he has not yet systematically compared schizophrenic and healthy brains. If it turns out that there are significant differences, future research can investigate how this proposed" brain microbioma "could maintain or threaten brain health, "the newspaper reported.
It's still early, but if future research can help explain the occurrence of this brain microbiomic and how it affects brain cells, it may be a paradigm shift that corresponds to the discovery of the intestinal microbioma, researchers say.