Scientists have identified two species of bacteria that may trigger multiple sclerosis (MS) in genetically identical twins. The study, published in PNAS, suggests that Eisenbergiella tayi and Lachnoclostridium are the most likely causes of the nerve-damaging disorder.
Researchers compared 81 pairs of identical twins, focusing on those where only one sibling had MS. They found that 51 microbial candidates diverged between affected and unaffected siblings, with two species consistently appearing at the top of the list.
The investigation involved transplanting ileal microbes from selected twins into germ-free mice bred to develop MS-like inflammation. The results showed that paralysis appeared within twelve weeks in mice given bacteria from the sibling with multiple sclerosis, while mice given microbes from the healthy twin stayed mobile throughout.
The two species belong to the Lachnospiraceae family of anaerobic bacteria, which are usually harmless and even beneficial. However, they can thrive on mucus sugars when dietary fiber is scarce, thinning the intestinal barrier and exposing immune sensors to microbial products.
Future research aims to test cause rather than correlation by using bacteriophages, viruses that hunt specific bacteria, to curb the two species before they spark immune trouble. The study provides a tangible target for MS treatment and highlights the importance of considering the wider community of gut bacteria in developing therapies.
Source: https://www.earth.com/news/scientists-think-they-found-two-key-bacteria-that-cause-multiple-sclerosis