The microbiota-gut-brain axis in depression: unraveling the relationships and therapeutic opportunities (2025)

Table of Contents

Introduction

  • Microbial composition changes during depressive states
  • Fecal microbiota transplantation can induce depression-like behaviors in animals
  • Probiotics shown promise in alleviating depressive symptoms
  • Key pathways through wich the microbiote influence depression via MGBA:
    • immune regulation -> citokine release
    • endocrine modulation -> HPA axis activity
    • neuronal signaling -> vagus nerve communication

Gut dysbiosis and depresssion

  • Gut microbiota affect neurotransmitter production, inflammation and stress response systems

Preclinical studies

  • CUMS (unpredictable mild stress) model is widely employed for inducing stress related behavior.
  • Alterations in mice subjected to CUMS:
    • Increase in proteobacteria
    • Increase in verrucomicrobia
    • Decrease in Bifidobacteriaceae
    • Decrease in Lactobacillaceae
  • FMT from CUMS mice to healthy mice induce depressive phenotypes
  • Probiotic interventions:
    • Enhance 5-HT synthesis
    • Normalize hyperactivity of the HPA axis