Yet another autoimmune related disorder caused by the microbiome! This time, rheumatoid arthritis.

Microbes are especially influential in the gut, which houses two-thirds of the body’s immune cells.

As the pathway for digestion, the gastrointestinal tract must deal with a constant stream of food-related foreign microbes, which must be monitored and, if they are harmful, destroyed. To do this, our intestines have developed an extensive immune system, whose effects reach far beyond the gut. Immune cells in the gut seem to be able to activate inflammatory cells throughout the body, including in joints.

While many scientists are confident of the link between the microbiome and arthritis, they haven’t pinned down what particular role bacteria play in triggering the disease.

wow.  i thought people were born with rheumatoid arthritis...  it sure would be nice if we could cure this disease from the inside out!

I thought so too! The microbiome controls way more than anyone realized. 

Eventually, it will be possible to treat arthritis by adjusting the microbiome. 

Dozens of researchers, including Scher and Blaser, are looking into a range of potential strategies to use bacteria as medicine for immune disorders. Already, millions of Americans ingest probiotics—cocktails of supposedly beneficial bacteria that claim to treat everything from acne to insomnia. Scher, like many microbiome scientists I spoke to, is skeptical that these products are useful. “Probiotics are generally safe and almost completely untested,” says Scher. “There’s this idea that you can simply replace certain bugs that are missing. I don’t think it’s as simple as that.” For one, he says, it’s not clear whether most microbes from probiotics can survive the digestive process.

Scher puts more faith in modifying the microbiome through diet. He notes that some patients with rheumatoid arthritis have benefitted from cutting out meat, or adopting a Mediterranean diet (high in fish, olive oil, and vegetables, and low in meat and saturated fat), though scientists don’t know exactly why this helps. In a separate study, Finnish researchers found that a vegan diet changed the gut microbiome, and that this change was linked to an improvement in arthritis symptoms.

Others are focusing on particular bugs over diet. At the Mayo Clinic, Taneja has found that a species of Prevotella bacteria, P. histicola, can prevent or halt the mouse versions of both rheumatoid arthritis and multiple sclerosis, an autoimmune disease of the brain and nerves. She is hoping to begin studies on humans in the next few months.

And some scientists are focusing not on the microbes, but on the compounds they produce. B. Fragilis, for instance, may ease autoimmune disease by releasing a molecule called polysaccharide A, or PSA. Harvard University microbiologist Dennis Kasper, who discovered the compound, has found that when given PSA, mice are protected from certain autoimmune diseases, including MS.

awesome.  healthy guts are the future!

Yes, if only it were simpler to make healthy guts.