Novel genetic, bacterial signature for IBD suggests a target for developing new therapies
Gastroenterologists have known that several genes and types of bacteria are associated with inflammatory bowel disease in children, including Crohn’s disease and ulcerative colitis. And while more than 160 areas of the genome have been identified as containing risk factors for IBD, no definite cause has been found.
Lee Denson, MD, director of the Inflammatory Bowel Disease Center, and his team have narrowed the focus to the ileum as the primary inductive site for IBD, and they have identified specific bacteria activated by ileal cells, depending on the IBD diagnosis. Their findings appeared July 8, 2014, in the Journal of Clinical Investigation.
By comparing ileal tissues from children with IBD and healthy tissues, they found that Crohn’s disease and ulcerative colitis patients had higher levels of proteobacteria and an increase in the activity of the DUOX2 gene. Some patients with Crohn’s disease also had lower levels of Firmicutes bacteria and lower activity of the APOA1 gene.
More than 80,000 children in the U.S. have been diagnosed with IBD, and the number is climbing. By identifying a microbial and gene expression “signature” for the disease, researchers are now better positioned to understand IBD, diagnose it more accurately and develop targeted therapies, Denson says.
Of special interest, he notes, is new knowledge about the role of the APOA1 gene, which is linked to changes in about 500 other genes. Patients with the APOA1 profile, regardless of the type of therapy or length of treatment, tend to have less successful outcomes.
“By characterizing this profile, we have potentially identified a new pathway to target to benefit kids who have not done well with other types of treatments,” Denson says.
