Integrated Gut Microbiome–Metabolome Profiles of Diarrhea-Predominant Irritable Bowel Syndrome: A Study from a Chinese Cohort

Abstract

Background: Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder, yet its underlying mechanism remains incompletely understood. This study aimed to elucidate gut microbiome dysbiosis and metabolic perturbations among Chinese patients with diarrhea-predominant IBS (IBS-D). Methods: Fecal samples were collected from 55 IBS-D patients (according to Rome IV criteria) and 29 healthy controls. Gut microbiome-metabolome signatures were obtained through 16S ribonucleic acid (rRNA) amplicon sequencing and untargeted metabolomics. Integrated bioinformatics analysis was conducted to investigate microbiome-metabolome characteristics in IBS-D patients. Results: Significant differences in microbiome profiles were observed between IBS-D patients and healthy volunteers. Utilizing machine learning algorithms, our investigation revealed a notable increase in gut microbes, including Sutterella, Lachnospira, Bacteroides, and Fusobacterium, in the IBS-D patients (p < 0.05). Conversely, Bifidobacterium, Blautia, and Romboutsia exhibited a decrease in IBS-D patients (p < 0.05). Furthermore, functional analysis indicated potential alterations in gut lipopolysaccharide (LPS) biosynthesis and disruptions in energy metabolism functions among IBS-D patients. In terms of metabolome profiles, significant upregulation was observed in metabolites such as 5′-S-methyl-5′-thioadenosine, S-adenosyl-methionine, creatine, adenine, and gamma-aminobutyric acid (GABA) in individuals with IBS-D (p < 0.05), suggesting a potentially pivotal role of these metabolites in the microbiota-gut-brain axis. Additionally, our study identified several significant associations between metabolites and microbes, further enhancing our understanding of the intricate interplay within the IBS-D microbiome. Conclusions: Our research highlights a microbiome-metabolome pattern in individuals with IBS-D, indicating that gut microbiome and fecal metabolites can serve as valuable indicators to distinguish between IBS-D patients and healthy individuals.