The Role of Lipoprotein and Gut Microbiome in Alzheimer's Disease: A Review of Novel Findings and Potential Applications

Alzheimer's disease (AD), a progressive neurodegenerative disorder, is inadequately comprehended, with hypotheses implicating amyloid-β, tau pathology, mitochondrial dysfunction, and epigenetic factors. Recent research underscores the significance of lipoproteins and the gut microbiota in the etiology of AD. Apolipoprotein E (ApoE), particularly the E4 subtype, emerges as a key genetic risk factor, influencing oxidative stress, synaptic defects, glucose metabolism, and amyloid-β clearance. Lipoprotein receptors, such as LRP-1, also influence the integrity of the blood-brain barrier, indicating potential for therapeutic applications. Novel therapies targeting lipoproteins, such as ALZ-801 and IDOL inhibitors, show promise in preclinical and clinical trials. Concurrently, the gut microbiome's impact on AD is increasingly recognized. Dysbiosis correlates with inflammation, mitochondrial oxidative stress, impaired autophagy, and neurotransmitter imbalances. Gut-derived metabolites, including phenylalanine and isoleucine, promote Th1 cell activation and microglial dysfunction, exacerbating AD pathology. Interventions, like probiotics, GV-971, and polyphenols, demonstrate efficacy in restoring microbial balance and mitigating cognitive decline. Crucially, bidirectional interactions between lipoproteins and the gut microbiome are implicated in AD. ApoE genotypes influence gut microbial composition, while microbiota- derived short-chain fatty acids and endotoxins modulate lipid metabolism and neuroinflammation. These interactions, mediated via the gut-brain axis, highlight novel therapeutic avenues. Current FDA-approved AD drugs face limitations in efficacy and side effects, underscoring the need for innovative strategies targeting lipoprotein-gut microbiome crosstalk. Integrating insights into lipoprotein biology and gut microbiota dynamics may offer transformative potential for AD treatment, emphasizing combinatorial approaches to modulate these interconnected pathways. Further research is warranted to elucidate mechanistic links and translate preclinical findings into clinical applications.