Unveiling Role of Gut Microbiota in Alzheimer’s Disease: Mechanisms, Challenges and Future Perspectives

Alzheimer's disease (AD) is a neurodegenerative condition characterized by neuroinflammation, tau hyperphosphorylation, Aβ (Amyloid beta) accumulation, and synaptic dysfunction. New research indicates that the gut-brain axis, a network of two-way communication that involves immunological signals, neural pathways, and microbial metabolites, makes dysbiosis of the gut microbiota essential to the pathogenesis of AD. Alterations in the gut microbiota's composition hinder the production of crucial metabolites, such as short-chain fatty acids, trimethylamine- N-oxide, and secondary bile acids, which affect neuroinflammatory cascades, mitochondrial bioenergetics, and synaptic plasticity. Furthermore, Toll-like receptor 4 -4-mediated microglial responses are triggered by Gram-negative bacterial lipopolysaccharides. This cascade promotes oxidative stress, chronic neuroinflammation, and disruption of the (BBB) blood-brain barrier, all of which encourage the accumulation of neurotoxic proteins. Microbiome-modulating therapies, such as probiotics, prebiotics, and synbiotics, have been shown to have neuroprotective properties. They work by restoring microbial diversity, increasing (Short-chain fatty acids) SCFA-mediated anti-inflammatory pathways, and reducing glial activation. In addition to promoting gut microbiota equilibrium, dietary approaches like the Mediterranean and ketogenic diets, which are enhanced with polyphenols and omega-3 fatty acids, also lower systemic inflammation and increase neural resilience. Furthermore, the potential of postbiotics and fecal microbiota transplantation to attenuate AD-related neurodegeneration and restore gut-derived metabolic balance is being investigated. Translating these methods into standardized clinical applications is difficult, though, because individual microbiome composition varies. It will be essential to address these complications through mechanistic research and extensive clinical trials to establish gut microbiota as a promising therapeutic target in AD.