Metagenomic symphony of the intestinal ecosystem: How the composition affects the mind

Key Scientific Achievements in Gastroenterology in 2024: Meeting of the Internal Medicine Sciences’ Council of the Department of Medical Sciences of the Russian Academy of Sciences

19.12.2024 состоялось очередное заседание Совета по терапевтическим наукам Секции клинической медицины РАН, посвященное ключевым научным достижениям гастроэнтерологии в 2024 г. В ходе заседания обсуждались актуальные вопросы гастроэнтерологической практики, включая проблемы профилактики рака желудка у пациентов с хроническим гастритом, а также приоритетные направления в диагностике и лечении патологии печени и различных заболеваний кишечника.

The role of the gut microbiome in Alzheimer's disease pathophysiology

PURPOSE OF REVIEW

The present review aims to provide an overview of the existing understanding of the role of the gut microbiome in the Alzheimer's disease pathophysiology.

RECENT FINDINGS

Recent research has highlighted the significant role of the gut microbiome in the pathogenesis of Alzheimer's disease via the gut-brain axis. However, the precise mechanisms by which gut microbiome and its microbial metabolites influence brain function are not clearly understood. Various factors, such as diet, drugs, lifestyle, stress, and microbial infections can provoke an imbalance in the gut microbiome homeostasis, known as dysbiosis. This dysbiosis impacts intestinal and blood-brain barrier permeability, elevating pro-inflammatory cytokines and contributing to neurodegeneration. Moreover, the gut microbiome generates neurotransmitters, amyloids, neurotoxins, and metabolites, which may play a role in systemic inflammation and in the disruption of physiological barriers.

SUMMARY

In the past decade, advancements in microbiome analysis technologies and bioinformatics have significantly enhanced our understanding of the role of the gut microbiome in Alzheimer's disease. The gut microbiome plays a pivotal regulatory role in the progression of Alzheimer's disease, and closely interacts with its pathogenesis, encompassing inflammation, amyloidosis, neurodegeneration, tauopathy, and co-pathologies.

Stress, microbiota, and the gut-brain axis in mental and digestive health

The prevailing mind-body dualism in contemporary medicine, rooted in reductionism and the fragmentation of knowledge, has impeded the development of a conceptual model that can adequately address the complexity of illnesses. Integrating biomedical data into a cohesive model that considers the mind-body-context interconnections is essential. This integration is not merely theoretical; rather, it has significant clinical implications. This is exemplified by chronic stress-related mental and digestive disorders. The onset and development of these disorders are intimately linked to chronic psychological stress via the brain-gut-microbiota axis. The present article examines the evidence and mechanisms indicating that stress is a primary factor and a potentiator of symptom severity in common mental health and digestive diseases, with a particular focus on human studies. However, due to space limitations, only a very general overview of preventive and therapeutic clinical strategies is provided. It is hoped that the recurring phrase, "Everything that happens to you is due to stress," will become more comprehensible to the physician after reading this manuscript.