# Host Transcriptome and Microbial Variation in Relation to Visceral Hyperalgesia

## TL;DR

This study explores how the host transcriptome and oral microbiome relate to visceral hyperalgesia, finding links between microbial diversity, gene expression, and pain sensitivity.

## Contribution

The study identifies specific microbial families and gene pathways associated with visceral hypersensitivity, linking microbiome variation to host RNA biology.

## Key findings

- 259 OTUs were associated with IVP through differential expression of 471 genes in inflammation and neural pathways.
- Lachnospiraceae, Prevotellaceae, and Veillonellaceae showed the strongest associations with IVP.
- Reduced oral microbial diversity was observed in participants with visceral hypersensitivity.

## Abstract

Background: Chronic visceral hypersensitivity is associated with an overstressed pain response to noxious stimuli (hyperalgesia). Microbiota are active modulators of host biology and are implicated in the etiology of visceral hypersensitivity. Objectives: we studied the association between the circulating mRNA transcriptome, the intensity of induced visceral pain (IVP), and variation in the oral microbiome among participants with and without baseline visceral hypersensitivity. Methods: Transcriptomic profiles and microbial abundance were correlated with IVP intensity. Host mRNA and microbes associated with IVP were explored, linking variation in the microbiome to host RNA biology. Results: 259 OTUs were found to be associated with IVP through correlation to differential expression of 471 genes in molecular pathways related to inflammation and neural mechanisms, including Rho and PI3K/AKT pathways. The bacterial families Lachnospiraceae, Prevotellaceae, and Veillonellaceae showed the highest degree of association. Oral microbial profiles with reduced diversity were characteristic of participants with visceral hypersensitivity. Conclusions: Our results suggest that the oral microbiome may be involved in systemic immune and inflammatory effects and play a role in nervous system and stem cell pathways. The interactions between visceral hypersensitivity, differentially expressed molecular pathways, and microbiota described here provide a framework for further work exploring the relationship between host and microbiome.