Gut microbiota and common gastrointestinal diseases: a bidirectional two-sample Mendelian randomized study

Area of Science:

• Microbiome research
• Gastroenterology
• Genetic epidemiology

Background:

• Emerging evidence suggests a link between gut microbiota composition and gastrointestinal diseases.
• However, the precise causal relationships remain largely undetermined.

Purpose of the Study:

• To investigate the causal relationships between gut microbiota and eight common gastrointestinal diseases.
• To identify specific gut microbial taxa that may causally influence gastrointestinal disorders.

Main Methods:

• Mendelian randomization (MR) analyses were employed to assess causality.
• Instrumental variables were derived from genome-wide association studies of 196 gut microbial traits.
• Statistical methods included Inverse Variance Weighted (IVW), MR-Egger, heterogeneity, pleiotropy, and leave-one-out analyses, with Bonferroni correction for multiple testing.

Main Results:

• MR analyses identified 62 potential causal relationships between gut microbiota and gastrointestinal diseases.
• Significant causal links were found between the gut bacterium Genus Oxalobacter and Crohn's disease (CD).
• A significant causal link was also identified between the gut bacterium Family Clostridiaceae1 and Irritable Bowel Syndrome (IBS).
• No significant heterogeneity or pleiotropy was detected, supporting the robustness of the findings.

Conclusions:

• This study provides evidence for specific causal roles of gut microbiota in gastrointestinal disorders.
• Findings suggest that targeting specific gut microbes, such as Oxalobacter and Clostridiaceae1, may offer therapeutic strategies for CD and IBS.
• The research offers valuable insights into the mechanisms underlying gut microbiota-mediated gastrointestinal diseases.