Faecal Microbiota Characterization in Lynch Syndrome (LS) Patients With or Without Colorectal Neoplasia ( AAS-Lynch-Microbiote)

Purpose: Through a pilot study, we performed whole gut metagenomic analysis in 17 Lynch syndrome (LS) families (not included here). In a second asymptomatic LS cohort (n=150, this ENA project) undergoing colonoscopy-screening program, individuals with early precancerous lesions were compared to those with a normal colonoscopy. Since bacteria are organized into different networks within the microbiota, we compared related network structures in patients and controls. We characterized bacteria taxonomy using Diamond/MEGAN6 and DADA2 pipelines and performed differential abundances using Shaman website. We constructed networks using SparCC inference tools and validated the construction's accuracy by performing qPCR on selected bacteria. Results: Significant differences in bacterial communities in LS-CRC patients were identified, with an enrichment of virulent bacteria and a depletion of symbionts compared to their first-degree relatives. Bacteria taxa in LS asymptomatic individuals with colonic precancerous lesions (n=79) were significantly different compared to healthy individuals (n=71). The main bacterial network structures, constructed based on bacteria-bacteria correlations in CRC (pilot study) and in precancerous patients (validation-study), showed a different pattern than in controls. It was characterized by virulent/symbiotic co-exclusion in both studies and illustrated (validation study) by a higher Escherichia/Bifidobacterium ratio, as assessed by qPCR. Conclusions: Enhanced fecal virulent/symbiotic bacteria ratios influence bacterial network structures. As an early event in colon carcinogenesis, these ratios can be used to identify asymptomatic LS individual with a higher risk of CRC. ===================================== See also : ClinicalTrials.org: Faecal Microbiota Characterization in Lynch Syndrome (LS) Patients With or Witho ut Colorectal Neoplasia (Microbiote) ClinicalTrials.gov ID NCT04791644 Sponsor Assistance Publique - H?pitaux de Paris Information provided by Assistance Publique - H?pitaux de Paris (Responsible Party) Last Update Posted 2021-05-18