A few years ago, the ice bucket challenge took the internet by storm, bringing attention to ALS, or Amyotrophic Lateral Sclerosis. ALS is a neurological disease and its causes are mostly unknown. One possible cause of ALS could be our gut microbiome. The gut microbiome is a huge source of important small molecule chemicals called metabolites (such as taurine, tryptamine and butyrate) in our body and has been implicated in many diseases, such as Alzheimer’s disease and autism.
A group of scientists investigated whether the microbiome plays a role in ALS. Using an ALS mouse model, they first treated ALS-mice with antibiotics to deplete the gut microbiome. They noticed that antibiotic treatment exacerbated ALS symptoms. Then, they zoomed in on the strains of bacteria that were found to be affected the most after antibiotic treatment and studied their individual effect. They determined that Ruminococcus torques & Parabacteroides distasonis worsened ALS symptoms in mice.
Encouragingly, these scientists uncovered that Akkermansia muciniphila (AM) significantly ameliorated ALS symptoms in mice, and also prolonged their lifespan. In order to further understand the mechanism behind this, they looked at the differences in metabolites inside the body of ALS-mice and AM-supplemented ALS-mice. They found a significant increase in nicotinamide (NAM, a form of vitamin B3 and a common dietary supplement) in AM-supplemented mice. Treating ALS-mice with NAM improved ALS symptoms, but did not prolong their lifespan, suggesting that there are more undiscovered mechanisms.
Lastly, the scientists analyzed blood and faeces samples from human ALS patients. ALS patients were found to have a decrease in genes involved in NAM metabolism and a decrease in NAM concentration in blood, verifying the clinical significance of their study. These results are very preliminary, but they highlight the potential of modulating the gut microbiome to treat ALS. This study examined one of the many mechanisms by which our gut microbiome can affect our body, and many more unexplored pathways remain to be studied.
Managing Correspondent: Wei Li
Original Article: Potential roles of gut microbiome and metabolites in modulating ALS in mice. Nature.
Media coverage: Commensal bacterium reduces ALS symptoms in mice. The Scientist.
Image Credit: Pixabay