Gut microbiota signatures in tissues of the colorectal polyp and normal colorectal mucosa, and faecesOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study compared gut microbiota across three sampling sites: normal colorectal mucosa, colorectal polyp tissue, and feces. The goal was to see how faithfully stool represents tissue-level communities. Samples were analyzed by 16S rRNA gene sequencing of the V3-V4 region on an Illumina MiSeq platform. Researchers measured alpha diversity (Ace, Chao, Shannon, Simpson), beta diversity by PCoA, differential taxa by LEfSe, and predicted function by PICRUSt2.
Who was studied?
The cohort was 24 adults with colorectal polyps and 16 healthy adults, all aged 18 to 80 years, enrolled before colonoscopy in Wuxi, China. This was a registered preliminary clinical trial. Polyp patients provided feces, normal mucosal biopsies, and polyp tissue. Healthy controls provided feces and normal mucosal biopsies. People with prior colon cancer or polyps, diabetes, recent antibiotics or probiotics, recent infection, or other intestinal disease were excluded.
What were the most important findings?
Mucosal and polyp tissues had significantly higher richness (Ace and Chao indexes) than feces (p less than 0.05). Community structure in feces differed clearly from tissue by PCoA, while mucosa and polyp tissue did not differ. The fecal microbiome did not differ between polyp patients and healthy adults, nor did the mucosal microbiome. Fusobacterium was enriched in mucosa and polyp tissue but rarely in feces, and its mucosal abundance was lower in polyp patients than healthy adults.
What are the greatest implications of this study?
The findings warn that fecal microbiota may not represent mucosal microbiota, which matters for studies of colorectal disease. Mucosal communities were richer and functionally distinct from stool. Fusobacterium appeared to be a normal colonizer of colonic mucosa, so an abnormal rise in feces may reflect mucosal injury rather than polyp presence itself. Because polyp and control microbiomes were broadly similar, the authors suggest major dysbiosis emerges later, during carcinogenesis, not at polyp formation.