Irritable bowel syndrome (IBS) is a common heterogeneous disorder rooted in a disruption of the gut-brain axis, characterized by abdominal pain and altered bowel habits. Altered gut microbiota is reported in IBS, with microbial metabolites, including bile acids (BA) and short chain fatty acids (SCFA), recognized to be potentially involved in the generation of IBS symptoms. Here, we demonstrate that microbiota-associated metabolites and gut motility can be used to distinguish between symptom patterns in IBS.
We collected fecal samples from healthy controls (n = 32) and individuals with irritable bowel syndrome (n = 162). We profiled the fecal microbiota by whole-genome metagenomics, quantified fecal BAs and SCFAs, and measured oro-anal transit time (OATT) using radiopaque markers. Individuals completed questionnaires reporting on gastrointestinal, non-gastrointestinal somatic, and anxiety and depressive symptom patterns.
As a novel approach to subgroup IBS patients, we used partitioning around medoids clustering of OATT, fecal primary BAs and SCFAs. We identified three clusters defined by distinct symptom patterns and differential gut microbial community profiles (between clusters: p < 0.001; compared to healthy controls: p < 0.05), highlighting the association between symptoms of IBS, gut motility and gut microbiota-associated metabolites. We demonstrate that the OATT is a key contributor to symptoms in IBS and that fecal SCFAs and BAs are associated with secretion and motility, but not sensitivity. Given that these clusters are based on host-gut microbiota co-metabolites and differentiate symptom patterns, our findings have the potential to inform future treatment strategies utilizing targeted dietary interventions stratified by clusters and/or metabolite profiles.