The Brain-Intestinal Mucosa-Appendix- Microbiome-Brain Loop

Area of Science:

• Neuroscience
• Immunology
• Microbiome Research

Background:

• The brain-gut axis is established early in fetal development, with maternal microbial exposures influencing fetal development.
• The microbiome plays a crucial role in educating neonatal mucosal tissues and skin, and in the post-natal development of mucosal lymphoid tissues.
• Intestinal mucosal maturation is linked to the brain-gut-brain axis, potentially influencing mood through microbiome shifts.

Purpose of the Study:

• To explore the role of intestinal resident macrophages in regulating the neuro-endocrine-immunological balance.
• To investigate the connection between gut dysbiosis, inflammation, and mood disorders.
• To consider the potential of probiotics as an adjunctive therapy for depression.

Main Methods:

• This commentary synthesizes current understanding of the brain-gut axis and microbiome.
• It proposes a model where intestinal macrophages regulate microbial translocation and maintain equilibrium.
• The authors discuss the implications of dysbiosis and inflammation on mood.

Main Results:

• Dysregulated pro-inflammatory signals from intestinal macrophages, due to dysbiosis, can disrupt the brain-gut loop, potentially leading to mood disorders.
• Intestinal resident macrophages are suggested to be key regulators of translocated microbes and metabolites.
• Sustained inflammation from overwhelmed macrophages may contribute to mood disorders.

Conclusions:

• The gut microbiome and intestinal immune system, particularly macrophages, are critical for maintaining neuro-endocrine-immunological homeostasis.
• Gut dysbiosis and subsequent inflammation are implicated in the pathophysiology of mood disorders.
• Probiotics show promise as an adjunctive treatment for depression, potentially by modulating the gut microbiome and reducing inflammation.