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IBD patients show dramatic fluctuations in gut microbiome composition
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Patients with inflammatory bowel disease have less stability in their gut microbiota composition compared with healthy individuals, with sometimes dramatic fluctuations that investigators characterized as “volatile dysbiosis,” according to new research.
“We know that there are some key beneficial microbes that are lower in number in people with inflammatory bowel disease. Sometimes the differences are quite substantial,” Janet K. Jansson, PhD, of the Department of Energy’s Pacific Northwest National Laboratory, Richland, Washington, said in a press release. “Our latest results show that patients affected by this condition also have a much less stable gut microbiome than healthy people.”
Previous cross-sectional studies have shown different IBD subtypes are associated with unique microbial signatures; in general, patients harbor fewer “beneficial microbes” and more bacteria like Enterobacteriaceae and E. coli. However, because most microbiome studies have evaluated few individuals at single time points, Jansson and colleagues sought to assess the long-term dynamic behavior of the gut microbiome in IBD patients compared with healthy individuals.
“It’s important to know not just what microbes are present, but also to understand how the microbial community changes as patients’ symptoms improve or worsen over time,” Colin J. Brislawn, BS, a scientist from the Pacific Northwest National Laboratory, said in the press release. “We explored the dynamic nature of the disease as it relates to the dynamic nature of the human gut microbiome.”
The team of investigators from Sweden, Spain, Germany and the U.S. used 16S rRNA sequencing to evaluate 683 fecal samples collected from 137 individuals every 3 months for up to 2 years; these included 49 patients with Crohn’s disease, 60 patients with ulcerative colitis, four patients with lymphocytic colitis, 15 patients with collagenous colitis and nine healthy controls.
They found that samples from healthy controls showed much more consistent gut microbiota composition over time compared with samples from IBD patients. In comparison, the IBD patients showed “dramatic shifts” in their microbiome composition, “with some bacteria disappearing almost completely at times — something that rarely happened in the healthy people studied,” according to the press release.
More than half of the microbiome was displaced by other microbes within a few months in some of the IBD patients, and the biggest shifts were observed in patients with ileal Crohn’s disease, especially those who had undergone surgical resection.
Further, changes in medication correlated with dramatic microbiome fluctuations. Patients who received steroids, for example, showed more fluctuations compared with those who did not, and patients who experienced a disease flare were also more likely to have dramatic fluctuations.
“These results will help guide therapies that will redirect the gut microbiome towards a healthy state and maintain remission in IBD,” the investigators wrote.
“The results are an important step in our aim to understand how the microbiome relates to the dynamics of inflammatory bowel disease,” Jonas Halfvarson, MD, a gastroenterologist at Örebro University in Sweden, said in the press release. “Ultimately, manipulation of the microbiome, aiming to mimic the situation and the trajectories of healthy individuals, might become an attractive treatment strategy to maintain IBD patients in remission, especially if immunosuppressants such as corticosteroids can be avoided.” – by Adam Leitenberger
Disclosures: The researchers report no relevant financial disclosures.
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