Crosstalk between Gut Microbiota and Central Nervous System: A Focus on Alzheimer's Disease

Abstract

The role of diet and gut microbiota in the pathophysiology of neurodegenerative diseases, such as Alzheimer's, has recently come under intense investigation. Studies suggest that human gut microbiota may contribute to the modulation of several neurochemical and neurometabolic pathways, through complex systems that interact and interconnect with the central nervous system. The brain and intestine form a bidirectional communication axis, or vice versa, they form an axis through bi-directional communication between endocrine and complex immune systems, involving neurotransmitters and hormones. Above all, studies suggest that dysbiotic and poorly diversified microbiota may interfere with the synthesis and secretion of neurotrophic factors, such as brain-derived neurotrophic factor, gammaaminobutyric acid and N-methyl D-Aspartate receptors, widely associated with cognitive decline and dementia. In this context, the present article provides a review of the literature on the role of the gutbrain axis in Alzheimer's disease.

C‐type lectin‐like receptor 2 and zonulin are associated with mild cognitive impairment and Alzheimer's disease

“…Probiotic treatment restores the diversity of gut microbiota and alleviates the psychopathological and histopathological manifestations in AD. 20,21 Zonulin is a marker of intestinal permeability. It helps the intestinal barrier to cope with various physiological and pathological challenges by dynamically regulating intercellular tight junction.…”

Oligosaccharides from Morinda officinalis Slow the Progress of Aging Mice by Regulating the Key Microbiota-Metabolite Pairs

“…Recently, a neurotoxin produced by Cyanobacteria that can cause neurodegenerative disease in humans was detected in the brain and cerebrospinal fluid of a patient with AD [63]. e key roles of the microbiome-gut-brain axis in the human lifespan [64,65] and the patterns of characteristic changes in the gut microbiota [66][67][68][69] are actively being studied; furthermore, the metabolome has been extensively studied separately in the context of AD [70][71][72][73]. e main contribution of this report is that it is a groundbreaking joint study that uses two histological platforms to study the gut microbiome and brain metabolome of AD models.…”

The Links Between the Gut Microbiome, Aging, Modern Lifestyle and Alzheimer's Disease

“…One of the possible explanations for the reduced number of species and quantitative composition of Bifidobacteria in the elderly people is the decrease in their adhesion to the intestinal wall due to changes in the chemical composition and structure of the colon mucous membrane, causing restricted functionality and immunological reactivity in the intestine as well as increased susceptibility to gastrointestinal infections (He et al, 2001). In turn, the bacteria Bifidobacterium and Lactobacillus are actively involved in the production of aminobutyric acid (γ-Aminobutyric acid, GABA) (Junges et al, 2018;Strandwitz, 2018). GABA is the most important inhibitory mediator of the central nervous system of humans and other mammals involved in neurotransmitter and metabolic processes in the brain.…”