Identifying Gut Microbiota associated with Gastrointestinal Symptoms upon Roux-en-Y Gastric Bypass

Area of Science:

• Gastroenterology
• Microbiome Research
• Surgical Outcomes

Background:

• Roux-en-Y gastric bypass (RYGB) is linked to persistent gastrointestinal (GI) symptoms.
• The precise causes of these symptoms are unclear, but alterations in the gut microbiome are suspected.
• Understanding the microbiome's role could reveal mechanisms behind post-RYGB GI issues.

Purpose of the Study:

• To determine if a pre-existing microbial imbalance before RYGB predicts later GI symptoms.
• To identify specific microbial groups associated with GI symptoms after RYGB.
• To investigate the relationship between gut microbiota composition and quality of life post-surgery.

Main Methods:

• Shotgun metagenomic sequencing of fecal samples from 67 RYGB patients before and 1 year after surgery.
• Assessment of GI symptoms using the Gastrointestinal Quality of Life Index (GIQLI) questionnaire.
• Machine learning models (extremely randomized trees) to identify microbial species linked to GI symptoms.

Main Results:

• Significant shifts in gut microbiome beta diversity were observed post-RYGB, indicating a dysbiotic profile.
• Specific microbial species were identified as strong predictors of total GIQLI (AUC 0.77) and change in GIQLI (AUC 0.83).
• Key predictive species included known butyrate producers and anti-inflammatory agents like Coprococcus eutactus and Faecalibacterium prausnitzii.

Conclusions:

• A healthy gut microbiota, characterized by beneficial commensals, is associated with better GI outcomes after RYGB.
• These beneficial microbes may offer protective effects against post-surgical GI dysfunction.
• The findings suggest that gut microbiome composition plays a crucial role in managing long-term GI health following RYGB.