- Research has shown that people living with MS have distinct gut bacteria.
- International researchers studied identical twins to control for genetic differences and investigated whether certain gut bacteria are linked to MS and can trigger MS-like disease.
- Over 50 types of bacteria differed between twins with and without MS and transferring bacteria from MS-affected twins into susceptible laboratory models triggered MS-like disease.
- Two types of bacteria were identified as likely culprits for triggering MS.
The link between the gut microbiome and MS
MS is a complex disease where the immune system mistakenly attacks myelin surrounding the nerves of the brain and spinal cord. While it is well-established that genetic, environmental, and behavioural factors contribute to the development of MS, the interplay between these factors is not well-understood.
Recently, researchers have started looking closely at the gut microbiome – the trillions of bacteria living in our intestines – due to its known influence on our immune system. These gut microbes help digest food, produce vitamins, and even influence inflammation in the body.
Large international studies have shown that people living with MS have different gut bacteria compared to those without MS, even when accounting for genetics and shared environment.
Research has also shown that transferring gut bacteria from people living with MS into genetically susceptible laboratory models can trigger MS-like disease, suggesting that certain bacteria may play a direct role in MS development. However, which bacteria may be involved remains unclear.
What did the researchers do?
Published in PNAS, researchers from Germany and the US aimed to identify specific gut bacteria that are linked to the development of MS and determine whether these bacteria can trigger an MS-like disease in laboratory models.
To investigate this, the researchers studied pairs of identical twins in which only one twin had MS, allowing them to compare the gut microbiota between genetically identical individuals with and without the disease.
To see if these bacteria are involved in the development of MS, the researchers took samples from the small intestine of selected twins and implanted them into laboratory models at high risk of developing an MS-like disease.
What did the researchers find?
Using high-throughput sequencing techniques, the researchers found over 50 types of bacteria that were different between those twins with and without MS.
To investigate the role of the gut bacteria in MS development, the researchers collected bacteria directly from the small intestine of the twins via endoscopy and transferred them into laboratory models genetically prone to develop an MS-like disease.
Laboratory models that received gut bacteria from twins affected by MS developed the disease at much higher rates than those given bacteria from twins without MS. Interestingly, in these models, females developed MS-like disease at a higher rate, mirroring the higher prevalence of MS in women.
The researchers identified the most abundant bacteria in laboratory models that developed MS-like disease and compared them to those found in intestinal samples from twins with MS – Eisenbergiella tayi and Lachnoclostridium – emerged as likely contributors to MS development in the laboratory models.
What is the significance of this?
This research moves beyond simply showing a link between gut bacteria and MS, and identifies two types of bacteria as likely culprits that may trigger or worsen MS.
By pinpointing these bacteria as potential disease facilitators, this study provides a much clearer target for future diagnostic tests and treatments.
This breakthrough opens new possibilities for diagnosing MS earlier, monitoring disease progression, and developing innovative treatments that target or modify gut bacteria.
Ultimately, understanding the gut-brain connection in MS could lead to more effective and personalised approaches to managing MS.
