Investigators are looking at how variables affect IBD studies

New analysis suggests stool type is better than biopsy results in study inflammatory bowel disease (IBD) Dysbacteriosis.

A team led by Lama Ezzat Hassan Abdel-Rahman, MSc, Department of Microbiology and Immunology, University of Otago, evaluated the reproducibility of IBD microbiome research.

Inconsistent studies

In recent years, several studies have explored the microbial environment in the gut of patients with Crohn’s disease and ulcerative colitis. However, there is one problem with the taxa associated with IBD and the environmental impact sizes were not consistent between studies.

“Compelling evidence indicates that the microbiome is essential for the pathogenesis of IBD,” the authors wrote. “It is widely believed, but not universally accepted, that the number of taxa in the gut microbiome of IBD patients was decreased compared to those without IBD. Other widely reported findings include greater variation within the microbiome structure (diversity of beta) in IBD patients compared with control subjects, and differences in taxonomic structure in both UC and CD patients”.

Inclusion and exclusion

In the meta-analysis, researchers identified 13 studies and analyzed how variables such as sample type — stool, biopsy or washing — affect the results of IBD gut microbiome studies between 2012-2020. The researchers used standardized bioinformatic methods for all primary data.

The studies included in the analysis included at least 50 human participants. The researchers also excluded studies involving microbiota-altering agents including fecal germ culture. All studies also included a group of healthy or non-IBD patients, with the exception of one study included in the analysis.

Results

The results showed that the decrease in alpha diversity was consistent in studies involving both Crohn’s disease and ulcerative colitis patients. However, it was more pronounced for patients with Crohn’s disease.

General disease contributed significantly to the variance in beta diversity in the majority of studies. While the effect size differed here, the effect of sample type was greater than that of disease.

The genus most closely associated with Crohn’s disease was Fusobacterium, but the genus associated with the disease were often inconsistent between studies. Stool studies also had less heterogeneity than biopsy studies, particularly for Crohn’s disease.

“Although we found few consistent taxonomic differences across the UC and CD data sets, our results show that IBD has a consistent effect on alpha and beta ecosystem diversity and suggest that stool type may be better than biopsy at representing dysplasia associated with IBD. Because of the low heterogeneity, the authors write, “We further demonstrate the utility of applying updated bioinformatic methods to historical data.”

Geographical location

Geographical location It may be a greater factor in the formation of gut microbiota than whether or not an individual has IBD, according to data from the 2022 European Crohn’s and Colitis Annual Meeting.

A team led by J.Hu, Icahn School of Medicine at Mount Sinai, Department of Genetics and Genomics, determined the compositions of the gut microbiomes of pregnant women and infants in Hong Kong and the United States with or without IBD.

Hong Kong pregnant women with IBD had a higher abundance of 15 sex-level classifications including BifidobacteriumAnd the stool And the Bacteroides Compared to pregnant women in the United States without inflammatory bowel disease. On the other hand, pregnant women with IBD in Hong Kong had a lower abundance of 6 taxa including Blautia and Turicibacter than pregnant women in the United States without IBD.

For children born to women without IBD, those in Hong Kong had a higher abundance of 3 taxa including stella glue And the Escherichia / Shigella and lower abundance Enterococci Compared to children born to women without IBD in the United States. After comparing gut alpha-microbiome diversity for both groups of women and infants, both were lower in Hong Kong (with IBD: s = 0.077; Without IBD: s = 0.13) and in the US (with IBD: s = 0.0024; Without IBD: s = 0.019).

the study, “Searching for concordance between studies of inflammatory bowel disease: a systematic meta-analysis‘online at Inflammatory bowel diseases.