Microbes in the brain?
Bacteria have been observed in the tissues of the human brain
An unexpected news was the message of a group of doctors from the University of Albama at a recent annual conference Neuroscience Societies in San Diego. The researchers told about the detection of bacteria in the tissues of a healthy brain. So far, not all of their colleagues are ready to believe in the reality of such a discovery.
There are many bacteria living in the human body, their total weight reaches one and a half kilograms. They usually live in the organs of the digestive system, on the surface of the skin and in other places, but bacteria have never been seen in brain tissues. Their penetration there was considered impossible, since the brain is well protected from foreign elements by a special system of cells and membranes, which is called the blood-brain barrier.
Research in the laboratory of Rosalinda Roberts (Rosalinda Roberts) is devoted to comparing the anatomical structures of the brain of healthy people and patients with schizophrenia. Five years ago, Courtney Walker, who works in this laboratory, first noticed strange rod-shaped objects on micrographs of brain tissues. For a long time, scientists could not confidently determine what it was, but finally, after consulting with bacteriologists, they came to the conclusion that they had bacteria in front of them. In a study presented at the conference, Roberts and her colleagues found such bacteria in the tissues of 34 brain samples, half of which belonged to healthy people and half to patients with schizophrenia.
Oval formations on a slice of the human brain to the left of the blood vessel are preliminary evidence of the presence of a "brain microbiome".
Bacteria are found among astrocytes – one of the types of neuroglia cells, a collection of auxiliary cells that surround neurons, providing them with nutrition and protection. Most of the bacteria were near the blood vessels, in the cells involved in the work of the blood-brain barrier. No traces of inflammation or other damage caused to the brain by bacteria were detected. RNA sequencing showed that most of the bacteria belonged to three groups characteristic of the human intestine: Firmicutes, Proteobacteria and Bacteroidetes. The researchers suggest that bacteria from the intestine are still able to penetrate the brain through blood vessels or nerves, overcoming the barrier.
To test the possibility of bacteria entering the brain during the time that elapsed between the death of a person and the collection of brain tissue samples, when the blood-brain barrier is disrupted, Robert and her colleagues conducted experiments with laboratory mice whose brains were removed immediately after death. Bacteria in their brains were detected, therefore, with a high probability, they penetrated there during the mouse's lifetime. If mice deprived of the bacterial population of the intestine were studied, then bacteria were not detected in their brains either.
Rosalida Robert admits that it is necessary to exclude any possibility of contamination of brain preparations with bacteria from the air or from surgical instruments during sampling or during their storage and preparation for research.
Portal "Eternal youth" http://vechnayamolodost.ru