Pathological depositions in human disease: converging mechanisms in atherosclerosis, Alzheimer's disease, and related disorders

Pathological deposition of endogenous material within tissues represents a central, unifying mechanism across a broad spectrum of prevalent human diseases. Atherosclerosis and Alzheimer's disease (AD) exemplify this paradigm: atherosclerosis is driven by subendothelial accumulation of apolipoprotein B-containing lipoproteins, cholesterol crystals, and hydroxyapatite, while AD is characterized by cerebral deposition of misfolded amyloid-β (Aβ) and/or hyperphosphorylated tau. Emerging evidence implicates substantial lipid dyshomeostasis in AD pathogenesis, including lipid-droplet-accumulating microglia and widespread lipidomic disruption, blurring the categorical boundary between "lipid" and "protein" deposition diseases. Apolipoprotein A-I (apoA-I) dysfunction bridges both domains: post-translational modifications and point mutations impair reverse cholesterol transport in atherosclerosis and simultaneously promote apoA-I amyloid fibril formation in systemic amyloidosis. Across atherosclerosis, AD, systemic amyloidoses, immune complex-mediated nephropathies, crystal arthropathies, and lysosomal storage disorders, shared pathophysiologic processes emerge: production-clearance imbalance, conformational transitions favoring aggregation or crystallization, microenvironmental modulation by extracellular matrix components, and chronic sterile inflammatory responses driven by NLRP3 inflammasome activation. In this review, we synthesize deposition biology using atherosclerosis and AD as primary paradigms, integrate mechanistic insights from related disorders, highlight convergent molecular pathways including NLRP3, proteostasis, and glymphatic clearance, and discuss diagnostic and therapeutic strategies. A conceptual framework unifying these conditions as variations on a common deposition theme is proposed to guide broadly applicable precision therapies.