A growing body of evidence suggests that the tens of trillions of microbes that normally live in the gut — the so-called gut microbiome — have far-reaching effects on how the human body functions. The microbial community produces vitamins, helps digest food, prevents the growth of harmful bacteria, and regulates the immune system, among other benefits.
Treatment for neurodegeneration
According to what was published by “Neuroscience News” quoting the journal “Science”, a new study conducted by researchers from the Washington University School of Medicine in St. Louis in laboratory mice, indicates that the gut microbiome also plays a major role in the health of the human brain.
The study found that gut bacteria – in part by producing compounds such as short-chain fatty acids – influence the behavior of immune cells throughout the body, including those in the brain that can damage brain tissue and exacerbate neurodegeneration in conditions such as Alzheimer’s disease. .
The new findings open doors to the possibility of reshaping the gut microbiome as a way to prevent or treat neurodegeneration.
Surprising conclusion
“We gave young mice antibiotics for just one week, and saw a lasting change in their gut microbes, their immune responses, and the amount of neurodegeneration associated with a protein called tau that they experienced as they aged,” said the study’s senior author and Distinguished Professor of Neuroscience, Professor David Holtzman. A surprising finding is that “manipulating the gut microbiome can be a way to influence the brain without putting anything directly into the brain.”
Evidence is accumulating that the gut microbiomes of people with Alzheimer’s disease can differ from those of healthy people. But it is not clear whether these differences are the cause or consequence of the disease — or both — and what effect an altered microbiome might have on the course of the disease.
Genetic modifications
To determine whether the gut microbiome plays a causal role, the researchers altered the gut microbiomes of mice predisposed to brain damage such as Alzheimer’s disease and cognitive impairment.
Mice were engineered to express a mutated form of the human brain protein tau, which accumulates and causes neuronal damage and atrophy in their brains by the age of 9 months.
They also loaded a variant of the human APOE gene, a major genetic risk factor for Alzheimer’s disease. People with one copy of the APOE4 variant are three to four times more likely to develop the disease than people with the more common APOE3 variant.
A new preventative approach
“This study may provide important insights into how the microbiome affects tau-mediated neurodegeneration,” said Professor Linda McGovern, director at the US National Institute of Neurological Disorders. “.
The findings suggest a new approach to preventing and treating neurodegenerative diseases by modifying the gut microbiome with antibiotics, probiotics, specialized diets, or other means.
Onset in middle age
For his part, Prof Holtzmann said the findings suggest that “treatment can be initiated in middle-aged people while they are still cognitively normal but on the verge of disability”, explaining that if treatment can be started in genetically sensitive adult animal models For neurodegeneration before the disease becomes apparent for the first time, and treatment is shown to work, this may be the point at which human clinical trials can begin.