Does the Microbiome Hold the Key to Treating Inflammatory Bowel Disease?
March 11, 2020
Gut instincts
Innovations in Digestive Health | Winter 2020
Fabio Cominelli, MD
The human body is teeming with bacteria, and that’s a good thing. The bacteria that occupy the gut — the gut microbiome — are providing valuable clues to help researchers develop more effective treatments for a host of conditions, from depression to inflammatory bowel disease (IBD).
Communities of microbes inhabit the gut, skin, eyes, nose, mouth and vagina, and more than 10,000 microbial species live in the body, estimates the National Institutes of Health Human Microbiome Project. A team led by Fabio Cominelli, MD, PhD, Chief Scientific Officer and Division Chief, Gastroenterology, University Hospitals Digestive Health Institute, and Professor of Medicine, Case Western Reserve University School of Medicine, is studying the gut microbiome to determine which microbes may help treat IBD. IBD collectively refers to Crohn’s disease and ulcerative colitis (UC).
Dr. Cominelli is currently testing about 20 strains of bacteria taken from Crohn’s disease patients. When the bacteria are transferred into germ-free mice, researchers can study how the mice react to a specific fecal microbiota transplant (FMT).
Results from these studies will help determine which composition from a fecal donor has the most beneficial effect. “We need more research to understand the mechanisms of action and which patients would benefit most,” says Dr. Cominelli.
PROMISING TREATMENT RESEARCH
The Food and Drug Administration has an enforcement discretion policy in place for FMT to accommodate patients with C. difficile infection who are not responsive to standard therapies and whose condition is life-threatening. Treatment for other conditions, including IBD, remains investigational but promising.
A 2017 publication for Gastroenterology Clinics of North America, authored by Dr. Cominelli with researchers from Case Western Reserve University Digestive Health Research Institute and Department of Medicine, stated that while studies show FMT has led to remission of some UC and Crohn’s disease patients, effects are “not universal, nor are they sustained in either of the two IBD groups.”1
At present, treatment for active IBD includes corticosteroids, immunosuppressive drugs or aminosalicylate (5-ASA) drugs. All of them can induce remission but come with significant side effects. FMT is considered a safe alternative therapy with fewer side effects.
DIET AND IBD
Diet helps control IBD symptoms, and additional research will help determine how it influences IBD outcomes. “The main mechanism of diet is alteration of the microbiome,” says Dr. Cominelli. “There, we want to identify which bacteria have positive or negative effect and recommend probiotics to treat IBD.”
Because problem foods vary by individual, gastroenterologists typically don’t give general diet recommendations. The Crohn’s & Colitis Foundation and the Patient-Centered Outcomes Research Institute are collaborating on research to study the influence of the Mediterranean diet and the Specific Carbohydrate Diet, which eliminates grains, processed foods and soy, among other foods.
Dr. Cominelli says a healthy diet rich in fruits and vegetables is the best place to start. A high-fat diet is pro inflammatory, he says, and not recommended.
People with or at risk of IBD may want to limit artificial sweetener consumption. A study published in 2018 and led by Dr. Cominelli examined the impact of Splenda on the gut microbiome and Crohn’s disease-like small intestine inflammation. In mice, results showed that while Splenda may alter the gut microbiome in both healthy and Crohn’s-prone hosts, only the Crohn’s-prone hosts showed increased inflammation.2
Dr. Cominelli and team will continue to study the influence of diet on IBD symptoms as well as the use of FMT to prevent IBD flares. Building on more than a decade of research on the gut microbiome, he hopes to have evidence that leads to complementary treatment based on diet, manipulation of the microbiome and probiotic use.
“There is a lot of study across disciplines into the microbiome,” says Dr. Cominelli. “It all ties back to gut health, which makes this an exciting time for our department.”
To refer a patient to UH Digestive Health Institute or to contact Dr. Cominelli, call 216-553-1976.
1Basson AR, Lam M, Cominelli F. Complementary and Alternative Medicine Strategies for Therapeutic Gut Microbiota Modulation in Inflammatory Bowel Disease and their Next-Generation Approaches. Gastroenterology Clinics of North America. 2017;46(4):689–729. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5909826/
2Rodriguez-Palacios A, Harding A, Menghini P, et al. The Artificial Sweetener Splenda Promotes Gut Proteobacteria, Dysbiosis, and Myeloperoxidase Reactivity in Crohn's Disease-Like Ileitis. Inflammatory Bowel Diseases. 2018;24(5):1005–1020. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5950546/