By David Borenstein MD, Executive Editor, theSpineCommunity.com
SPARTAN (Spondyloarthritis Research and Training Network) is the scientific organization of physicians and patient organizations dedicated to the study of inflammatory disorders of the spine, like ankylosing spondylitis. The 14th meeting of this group brought researchers from North America to Denver to discuss new advances in these disorders as well as the development of treatment recommendations for spondyloarthritis.
A major focus of the SPARTAN meeting was the microbiome and ankylosing spondylitis. The microbiome consists of trillions of bacteria that exist in our gastrointestinal tract. Most organisms are symbiotic, a mutually beneficial relationship. That is, they supply essential factors for us and we supply nutrients for them. For example, vitamin K for coagulation is a product of this interaction.
Humans have an entire component of their immune system directed at controlling the microbiome. IgA, an immunoglobulin, has action primarily within systems exposed to the environment like the gastrointestinal tract and the respiratory system.
Animal models exist in the rat that mimic ankylosing spondylitis (AS) in humans. If spondylitis-prone rats are kept bacteria-free, they do not develop spondylitis.
Certain organisms, segmented filamentous bacteria, have the potential to cause immune cells in the GI tract to generate cellular messengers, cytokines, that mediate inflammation and tissue damage. For example, interleukin-17 is induced by segmented filamentous bacteria in the GI tract. IL-17 is recognized as one of the causes of the signs and symptoms of AS. A recently approved biologic drug that decreases levels of Il-17, secukinumab, is proven to improve individuals with AS.
Also of interest are the organisms that exist in individuals who are HLA-B27 positive. HLA B27 is a human genetic marker associated with increased risk of developing AS. Individuals with HLA-B27 have different organisms that populate their gut than individuals who are B27 negative.
Many questions remain regarding the importance of the microbiome and human disease. AS is just one example of such an illness. I would not be surprised that future therapy for a wide variety of illnesses will include modification of the organisms in our gut.
Reference: Jim Rosenbaum. The Role of Microbiome in Spondyloarthritis. Proceedings from the 2016 Annual Spartan meeting.