Bacterial sugars in the gut may contribute to neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), new research indicates. Both conditions lead to neuron death, impacting muscle movement and cognitive functions. Understanding the triggers behind these diseases remains a challenge, prompting researchers from Case Western Reserve University to investigate the potential role of gut bacteria.
Research Overview
The study’s researchers focused on a specific type of glycogen produced by gut bacteria. They discovered that this sugar is linked to brain inflammation and neuron death. Aaron Burberry, an assistant professor of pathology, noted, “Harmful gut bacteria produce inflammatory forms of glycogen that trigger immune responses damaging the brain.” The team aims to identify treatments targeting this bacterial sugar.
Gene Variations and Triggers
Both ALS and FTD can be influenced by a variation of the C9ORF72 gene. However, not everyone with this variant develops neurodegenerative disorders. The research aimed to uncover additional triggers affecting individuals carrying the gene variation. The connection between inflammatory glycogen and ALS/FTD suggests that microbial factors could play a significant role.
Methodology and Findings
The researchers engineered mice lacking the C9ORF72 gene to mimic the gene variant found in humans. Various gut bacteria mixes were tested, resulting in the identification of Parabacteroides merdae, a strain producing inflammatory glycogen. Introducing this bacteria into germ-free mice caused inflammation and compromised the blood-brain barrier.
- Out of 22 ALS patients, 15 exhibited elevated inflammatory glycogen levels.
- One FTD patient also had higher glycogen levels.
- Only four out of 12 healthy controls showed similar findings.
This indicates that the immune system responds aggressively to the harmful sugars, potentially impacting brain function. The protein from the C9ORF72 gene seems to regulate glycogen, raising concerns over the genetic variation’s implications.
Future Directions
One promising discovery from the study was the administration of alpha-amylase, an enzyme that broke down glycogen in affected mice. This treatment reduced inflammation and extended their lifespans, albeit without improving motor functions. The researchers suggest this could lead to gut-targeted therapies for ALS and FTD.
Implications for Human Studies
As scientists explore the connection between gut health and brain conditions, future research will involve larger human trials. Investigations will focus on various types of glycogen-producing bacteria and how they interact with neurodegenerative diseases over time. Burberry stated, “Larger studies will survey gut microbiome communities in ALS/FTD patients before and after disease onset.” Clinical trials aimed at determining whether glycogen degradation can slow disease progression may commence within a year.
This research was published in Cell Reports and emphasizes the importance of understanding gut bacteria’s impact on neurodegenerative conditions. Ongoing studies will shed light on the potential for innovative treatments targeting these microbiome interactions.
