AlzheimerâÂÂs Disease Pathogenesis: The Denied Access Model

Abstract

Currently, AD has no cure and only treatments for the symptoms exist. Modern research still debates the toxic component of AD and the exact mechanism causing neurodegeneration. A hallmark of the disease is the production of the amyloid-beta (As) peptides and eventual self-assembly of these peptides into fibrils and extracellular As plaques. Both plaques and oligomers are proposed to be the direct cause of AD, but it remains unclear how the physical presence of these structures affect neuronal function and pathogenesis. Biomolecule aggregation is known to play a role in the pathogenesis of numerous diseases by restricting diffusion and bulk flow, and the same restriction could occur in the brain due to the dense amyloid plaques forming in the extracellular space. These plaques could prevent proper flow and diffusion of essential nutrients and prevent cellular waste removal by acting as extracellular channel blockades; however, limited models exist that address these issues. Alternative models and molecular tools need to be developed which focus on diffusion and bulk flow in relation to neural function and the physical presence of amyloid plaques. This review aims to evaluate the effect of the plaques on diffusion and bulk flow in relation to neural function in the brain.