Changes in the balance of microbes that live in our gut — our personal microbiome — could trigger multiple sclerosis (MS), a new study suggests. Scientists from Brigham and Women's Hospital in Boston presented their work last month at the MS Boston 2014 meeting.
Since the gut microbiome plays a key role in shaping a person's immune system, researchers wanted to know what differences they might find between the bacteria in a healthy person’s gut and the bacteria carried by someone with MS.
What Roopali Gandhi, Ph.D., an assistant professor of neurology, and her team found was that people with MS have a microbiome that is decidedly different from that of a healthy person.
MS patients have a much higher concentration of a microbe known as Archaea, whose cell walls and lipids make it a strong immunogenic organism, meaning that it can trigger inflammation. The researchers also noticed that MS patients have lower levels of Butyricimonas, a microbe that has anti-inflammatory properties.
In fact, not only is the microbiome different in patients with MS, but the makeup of bacteria varies depending on where the patient lives. People with MS living in California have a different microbiome from those living in New York. To combine their efforts and share their data to get the "big picture," several researchers have come together to form the MS Microbiome Consortium.
These findings support the theory among academic researchers that MS is highly influenced by the microbiome. Some believe it may even be where the disease begins.
Getting Inside the Gut Microbiome
We think of our bodies as belonging only to us and of bacteria and other microbes as foreign invaders that make us sick. When we have an infection, we kill them with antibiotics in order to get better. But that’s not the whole story.
There are trillions of single-celled organisms that live in our bodies, many residing in our gut. There are more microbes in our gut than the number of cells that make up our entire bodies. You might correctly say we are more microbe than human.
We cohabitate with our microbes in a mutually beneficial relationship. The bacteria help us digest food, they excrete enzymes and vitamins, and they interact closely with our immune system. In return, we feed them and give them a place to colonize.
This relationship is why some foods are considered “inflammatory” and others “anti-inflammatory.” The type of microbes that feast on them — and flourish — determines whether they will trigger inflammation or stop it.
The idea that this mutual relationship with our microbiome, if gone awry, may trigger autoimmune diseases is becoming a focal point as researchers learn more about MS.
The suspected link between the gut microbiome and autoimmune disease is not a new concept. The connection is easier to see in other diseases, such as type 1 diabetes or Crohn’s disease, where the food-gut-immune system interplay seems more obvious.
Stopping MS Takes Guts
Knowing that the microbiome plays a role in MS is only the first step toward taming the inflammatory process. It’s not enough to merely observe that the levels of microbes are out of balance. Knowing exactly what roles they play and delving further into their interactions with the immune system will help guide the next steps in research.
“These studies are required to understand how particular microbes could influence the disease biology,” Gandhi told Healthline, “and if these could be used to decrease the inflammatory function and increase the regulatory function of immune cells.”
Future MS therapies may deliver just the right mix of microbes to restore balance in the microbiome and effectively treat the disease. Gandhi and her team are currently studying the microbes her study identified in order to take a closer look.
Could knowing which microbes are missing in people with MS be used to effectively treat patients? “Yes, it could be,” Gandhi said, “and we are testing that possibility in animal models now.”
A capsule full of microbes may be the future of MS therapy, but some scientists are also considering other delivery methods.
A fecal transplant, which involves taking feces from a healthy person and putting them into the body of a sick person, has been shown to restore microbial balance in patients suffering from serious infections with C. difficile after taking a long course of antibiotics.
When asked if fecal transplants could work for MS patients, Gandhi said, “Conceptually it should work, but more confirmatory studies in animal models are needed before we investigate it further in humans.”