IDDF2023-ABS-0274 Bacteroides vulgatus affects colitis and depression-like behavior in mice: implications for the gut-brain connection

Background

Patients with Inflammatory bowel disease (IBD) have a high prevalence of depression. Gut microbiota dysbiosis has been reported to play an important role in IBD and depression. However, few studies have explored the characteristic microbiota of IBD patients with depression (IBDD) and their role in IBDD.

Methods

We performed deep metagenomic sequencing and 16S rDNA qPCR to characterize the gut microbial community of IBDD patients and IBD patients without depression (IBDND). Then, we assessed the effect of microbiota on colitis and depression in a dextran sulfate sodium salt (DSS)-induced colitis mouse model and lipopolysaccharide (LPS)-induced depression mouse model. Furthermore, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to analyze microbiota-derived metabolites involved in gut-brain communication.

Results

Our results showed that the fecal abundance of Bacteroides vulgatus (B. vulgatus) was decreased in the IBDD compared with IBD. In the DSS-induced colitis mouse model, B.vulgatus group mice showed significantly lower Disease activity index (DAI) scores, less weight loss and longer colon lengths than DSS group mice. Moreover, B.vulgatus relieves depression-like behavior in the DSS-induced colitis mouse model and LPS-induced depression mouse model. Furthermore, the key metabolite of B. vulgatus has been identified as 4-HPAA, and animal studies have demonstrated that 4-HPAA relieves intestinal inflammation and alleviates depressive-like behavior through the gut-brain axis.

Conclusions

In conclusion, B. vulgatus and B. vulgatus-derived 4-HPAA ameliorate intestinal inflammation, and relieve depressive symptoms through the gut-brain axis. The administration of B. vulgatus or 4-HPAA supplementation provides a promising therapeutic strategy for treating IBD, especially IBDD.