Healthy intestinal flora can protect the brain
An intact intestinal flora is an important contribution to the protection against infections, allergies and other diseases. However, it may also keep the brain healthy as German researchers reported last summer in the renowned scientific journal Nature Neuroscience. The bacterial composition in the human intestine therefore has an influence on immune cells in the brain. Scientists from the Max Delbrück Center for Molecular Medicine in the Helmholtz Association( MDC) have reported that a special strain mediates immune cells between the intestinal flora and the brain."The findings have important implications for the long-term use of antibiotics, but could also help alleviate the symptoms of psychiatric conditions," the MDC writes in a press release.
Bowel and brain "talk" to each other
As the message says, "the bowel and the brain are talking. Hormones, metabolic products or direct nerve connections. Another binding member is a particular population of immune cells from the group of monocytes, such as Dr. Susanne Wolf from the MDC research group around Prof. Helmut Kettenmann together with colleagues from the University of Magdeburg, Charité - Universitätsmedizin Berlin and the US National Institutes of Health( NIH).The experts published their results in the journal "Cell Reports".
Microbiom with antibiotics switched off
In order to reach their findings, the researchers switched mice the microbiom, ie the bacteria of the intestinal flora, with an antibiotic cocktail. When they compared the rodents to untreated animals, they observed significantly less newly formed nerve cells in the hippocampal region of the brain. According to the researchers, the memory of the mice also deteriorated, because this formation of new brain cells - called "neurogenesis" - is important for certain memory functions. When the microbiome was switched off, the number of a particular immune cell population in the brain, the Ly6Chi monocytes, decreased significantly, together with neurogenesis.
Experimental animals cured with different strategies
When Wolf and her team only removed these cells from the micethe neurogenesis. They administered Ly6Chi monocytes to antibiotic-treated animals, and again increased neurogenesis. According to their own data, the scientists cured the antibiotic-treated animals with two different strategies. If the mice used a mixture of selected bacterial strains, or if they were undergoing voluntary training in the mouse impeller, the negative effects of the antibiotics were reversed. The monocyte number recovered as well as the memory performance and neurogenesis. A recovery of the intestinal flora with the microbiome of untreated animals was not successful according to the experts.
Consequences for the treatment of psychiatrically ill persons
According to Wolf, the hitherto unknown intermediary function of the immune cells is of particular scientific interest."With the Ly6Chi monocytes, we have perhaps discovered a new general pathway from the periphery to the brain." Transmitted to humans, the results do not mean that all antibiotics interfere with the brain function because the combination of drugs used was extremely strong."However, similar effects may be expected for antibiotics over a long period," says Wolf. The antibiotics also affect the neurogenesis without any detours over the intestinal flora, as further results of the research team show. In addition, the new study also has implications for the treatment of persons with psychiatric disorders, such as schizophrenia or depression patients with impaired neurogenesis, "Susanne Wolf said:" These patients may be able to help probiotics as well as medicines and sports. To test this, we would like to conduct clinical pilot studies together with the Charité. "(Ad)