Transplanted Microbes Alter Gut Function and Behavior

Such findings could facilitate development of improved diagnostics as well as effective treatments to replace current symptom-targeting treatments.

The underlying causes of IBS are unknown, which has hindered development of improved diagnostics and therapeutics. The research team, led by Prof. Premysl Bercik and Dr. Stephen Collins of McMaster University (Ontario, Canada) in collaboration with researchers from University of Waterloo (Ontario, Canada), explored effects of fecal microbiota from human IBS patients with diarrhea, with or without anxiety, on gut and brain function in recipient mice. Using fecal transplants, they transferred microbiota from these IBS patients into germ-free mice. The mice developed changes both in intestinal function and behavior reminiscent of the donor IBS patients, compared to mice that were transplanted with microbiota from healthy individuals.

The researchers found that aspects of the illness that were impacted through fecal transplants included gastrointestinal transit (the time it takes for food to leave the stomach and travel through the intestine); intestinal barrier dysfunction; low-grade inflammation; and anxiety-like behavior.

This study “moves the field beyond a simple association, and towards evidence that changes in the microbiota impact both intestinal and behavioral responses in IBS," said study first author Giada De Palma, research associate at McMaster U.

They authors noted that the study "adds to evidence suggesting that the intestinal microbiota may play some role in the spectrum of brain disorders ranging from mood or anxiety to other problems that may include autism, Parkinson's disease, and multiple sclerosis." Further studies are needed to better define the relationship in these conditions. The authors suggested "microbiota-directed therapies, including pre- or probiotic treatment, may be beneficial in treating not only intestinal symptoms but also components of the behavioral manifestations of IBS."

"Our findings provide the basis for developing therapies aimed at the intestinal microbiota, and for finding biomarkers for the diagnosis of IBS," said Prof. Bercik.

The study, by De Palma G et al, was published March 1, 2017, in the journal Science Translational Medicine.