Study Investigates Possible Environment Trigger for MS

A bacterium that may trigger
multiple sclerosis has been identified by a research team from Weill Cornell
Medical College and The Rockefeller University. Their study, published in PLoS
ONE, is the first to identify the bacterium, Clostridium (C.) perfringens type
B, in humans.


The scientists say their
study is small and must be expanded before a definitive connection between the
pathogen and MS can be made, but they also say their findings are so intriguing
that they have already begun to work on new treatments for the disease.


“This bacterium produces
a toxin that we normally think humans never encounter. That we identified this
bacterium in a human is important enough, but the fact that it is present in MS
patients is truly significant because the toxin targets the exact tissues
damaged during the acute MS disease process,” say the study’s authors.


“Work is underway to
test our hypothesis that the environmental trigger for MS lays within the
microbiome, the ecosystem of bacteria that populates the gastrointestinal tract
and other body habitats of MS patients.”


The study describes discovery
of C. perfringens type B in a 21-year-old woman who was experiencing a flare-up
of her MS. The woman was part of the Harboring the Initial Trigger for MS
(HITMS) observational trial. C. perfringens, found in soil, is one of the most
common bacteria in the world. It is divided into five types. C. perfringens
type A is commonly found in the human gastrointestinal tract and is believed to
be largely harmless.

C. perfringens types B and D carry a gene
(epsilon toxin) that emits a protoxin — a non-active precursor form of the
toxin — which is turned into the potent “epsilon” toxin within the
intestines of grazing animals. The epsilon toxin travels through the blood to
the brain, where it damages brain blood vessels and myelin, the insulation
protecting neurons, resulting in MS-like symptoms in the animals.

Researchers say they do not know how humans are infected with C. perfringens
type B or D, but they are studying potential routes of exposure. The scientists
are also in the first stages of investigating potential treatments against the
pathogen.  A vaccine for humans is possible — there is already a vaccine
available for farm animals, but it requires repeat immunizations and they are
also investigating the possibility of developing small-molecule drugs that
prevent the toxin from binding to its receptor. Another approach is the
development of a probiotic cocktail that delivers bacteria that compete with,
and destroy, C. perfringens types B and D.