06 March 2017

Human bacteria have changed the behavior of mice

Microflora from people with intestinal disease made mice anxious

Kirill Stasevich, "Science and Life", based on the materials of The Scientist: Human Gut Microbe Transplant Alters Mouse Behavior

The intestinal microflora affects not only the metabolism, but also the brain, and the experiments of researchers from McMaster University are another proof of this. Premysl Bercik and his colleagues collected microflora samples from several healthy people and patients with irritable bowel syndrome, and then transplanted human bacteria into mice that did not have their own microflora.

Irritable bowel syndrome partly resembles poisoning or intestinal disorder: abdominal pain, digestive problems, in addition, it is often accompanied by headache, back pain, as well as mental symptoms – patients experience anxiety or depression. According to statistics, 15-20% of adults suffer from this disease, and it is believed that one of their direct causes here is anomalies in the intestinal microflora: some bacteria become abnormally many, and some are too few.

After three weeks, it turned out that in mice that received microflora from people with irritable bowel syndrome, food passes through the digestive tract faster, that they showed signs of mild inflammation, and that metabolic products are in a different proportion than in animals that received microflora from healthy people.

This could be expected, after all, bacteria directly affect the work of the intestine, metabolism, and the immune system responsible for the inflammatory response. But the main thing is that the behavior of mice has also changed: in the article Science Translational Medicine (De Palma et al., Transplantation of fecal microbiota from patients with irritable bowel syndrome alters gut function and behavior in recipient mice), the authors write that animals have become more restless and anxious – which, as mentioned above, it often happens with irritable bowel syndrome. By the way, two years ago we talked about other experiments of the same group of researchers – then they found out that the gastrointestinal microflora "remembers" the stress suffered by the host, and then, after some time, gives a response alarm signal to the brain.

In most such works, a certain correlation between the microflora compositions and the characteristic symptoms of the host organism is usually stated, in this case, the researchers tried to show a causal relationship between one and the other. Since the microflora was transplanted into mice in a complex, it is now necessary to understand which microbes "warm up" the immune system, cause depression and increased intestinal patency, and how exactly they do it.

The intestine is directly connected to the brain (in particular, one of the branches of the vagus nerve), and probably some metabolic products, the level of which increases due to certain bacteria, can literally "act on the nerves". However, before building any hypotheses here, we need to wait for new research.

Portal "Eternal youth" http://vechnayamolodost.ru  06.03.2017

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