IBD Surgery Affects Microbiome Diversity

Brigid S. Boland, MD

Gut microbiome diversity and metabolome is adversely affected by intestinal surgery in patients with irritable bowel disease (IBD), according to new study findings.

In a prospective assessment conducted via data from patients with ulcerative colitis or Crohn’s disease, investigators observed a negative association between invasive care and microbiome and metabolome changes.

The study, led by Brigid S. Boland, MD, of the University of California San Diego (UCSD) and colleagues, connotes the need for long-term assessment of patients’ health outcomes following gastrointestinal surgery.

Boland and colleagues sought to characterize and contrast changes to the microbiome and metabolome in patients following differing surgeries for patients with IBD, including colectomies and ileocolonoic resections.

“Many studies have investigated the role of the microbiome in inflammatory bowel disease (IBD), but few have focused on surgery specifically or its consequences on the metabolome that may differ by surgery type and require longitudinal sampling,” they wrote.

They conducted their prospective analysis using 332 stool samples collected from 50 patients with ulcerative colitis, and 79 patients with Crohn’s disease—129 total. Among them, 21 patients with Crohn’s disease had undergone ileocolonic resections; 17 patients had colectomies.

Microbiomes and metabolomes 24 months post-surgery in patients were characterized through shotgun metagenomics, untargeted liquid chromatography, and tandem mass spectrometry metabolomics.

Boland and colleagues refrained from using rNA amplicon analyses due to limitations in microbiome taxonomic resolution, as well as lessened insight into functionality. Their preferred combined methods allowed for the assessment of different data types as biomarkers for clinical status, including microbiome volatility and clinical status.

The role and timing of surgery in patients with IBD was a crucial clinical consideration, as assessments have wavered in defining invasive care as either “last resort” care or “alternative therapy” for patients with Crohn’s disease.

“However, the potential long-term adverse effects of surgery, especially in terms of impact on the microbiome and/or metabolome, have not yet been fully elucidated,” they wrote.

Investigators observed that species and metabolite diversity both differed significantly among patients with IBD to receive surgery versus those who did not. Particularly, escherichia coli expanded “dramatically” among patients to have undergone surgery.

They concluded that intestinal surgeries appear reduce gut microbiome and metabolome diversities in patients with IBD, and that such changes may even persist over time.

“Surgery also further destabilizes the microbiome (but not the metabolome) over time, even relative to the previously established instability in the microbiome of IBD patients,” they wrote. “These long-term effects and their consequences for health outcomes need to be studied in prospective longitudinal trials linked to microbiome-involved phenotypes.”

The study, “Gastrointestinal Surgery for Inflammatory Bowel Disease Persistently Lowers Microbiome and Metabolome Diversity,” was published online in Inflammatory Bowel Diseases.