Recapitulating Alzheimer’s disease pathophysiology with a microfluidic neurospheroid-grafted endothelial barrier model

BACKGROUND: Traditional two-dimensional (2D) models do not adequately capture the complex cellular interactions, brain-specific architecture, and progressive pathology of Alzheimer's disease (AD). Three-dimensional (3D) organoid and microfluidic technologies provide more physiologically relevant platforms for studying AD-associated neurovascular dysfunction. METHODS: We developed a membrane-free microfluidic endothelial barrier model integrated with neurospheroids derived from familial AD (FAD) neural progenitor cells. Human endothelial cells were cultured within perfusable microfluidic channels to establish a vascular-like interface rather than a fully specialized BBB endothelium. Pre-differentiated neurospheroids were grafted into the brain chamber. Endothelial barrier integrity, tight-junction expression, phosphorylated tau (pTau), and Aβ42/Aβ40 production and distribution between compartments were assessed using immunofluorescence imaging and ELISA. RESULTS: The neurospheroid-grafted endothelial barrier construct captured key AD-associated phenotypes. ReN-AD-D4 models exhibited increased endothelial barrier permeability, reduced ZO-1 expression, and elevated pTau relative to controls. The platform supported endogenous Aβ generation, accumulation, and endothelial-associated deposition at the endothelial barrier. ELISA demonstrated differential Aβ42 and Aβ40 distribution, consistent with isoform-selective behavior reported in AD pathology. Collectively, these results indicate co-occurring neuronal and endothelial barrier alterations within the integrated 3D system. CONCLUSION: This microfluidic endothelial barrier-neurospheroid platform enables quantitative assessment of amyloid-β accumulation, spatial distribution, and compartmentalized secretion alongside tau pathology and endothelial barrier integrity changes. Integrating human endothelial monolayers with FAD-derived neurospheroids, the system is scalable and compatible with high-content imaging. Although it does not model BBB-specific transport mechanisms, it provides a robust framework for hypothesis-driven studies of neurovascular interactions and therapeutic screening applications.