Scientists have identified a new gut-brain connection in the neurodegenerative disease amyotrophic lateral sclerosis (ALS), also known as motor neurone disease (MND) that causes the death of neurons controlling voluntary muscles. The gut microbiome could influence the severity of disease and could be a potential target for therapy.
The gastrointestinal tract (GIT), which hosts billions of bacteria, microorganisms and viruses, plays an important role in both the maintenance of health and the development of diseases.
The researchers found that in mice with a common ALS genetic mutation, changing the gut microbiome using antibiotics or fecal transplants could prevent or improve disease symptoms.
The findings provide a potential explanation for why only some individuals carrying the mutation develop ALS. They also point to a possible therapeutic approach based on the microbiome.
The researchers initially studied the ALS genetic mutation by developing a mouse model at their Harvard lab facility. The mice had an overactive immune response, including inflammation in the nervous system and the rest of the body, which led to a shortened lifespan.
In order to run more detailed experiments, the researchers also developed the mouse model in their lab facility at the Broad Institute. Unexpectedly, although the mice had the same genetic mutation, their health outcomes were dramatically different.
Looking for environmental differences between the mice, the researchers honed in on the gut microbiome. By using DNA sequencing to identify gut bacteria, the researchers found specific microbes that were present in the Harvard facility mice but absent in the Broad facility mice, even though the lab conditions were standardised between facilities.
The researchers then tested ways to change the microbiome and improve outcomes for the Harvard facility mice. By treating the Harvard facility mice with antibiotics or fecal transplants from the Broad facility mice, the researchers successfully decreased inflammation.
The researchers noted an important gut-brain connection while studying the connection between genetic and environmental factors in the course of ALS.