Extracellular matrix components and amyloid in neuritic plaques of Alzheimer's disease.

1. There has been an enormous amount of information relating to the molecular components involved in Alzheimer's disease. 2. Recently some attention has been focused on the extracellular matrix (ECM) components present in the brain amyloid deposits. 3. Here we discuss, the direct involvement of ECM constituents such as laminin, collagen type IV, fibronectin, proteoglycans (PGs) and basic fibroblast growth factor in the formation of neuritic plaques. 4. We suggest that PGs act as nucleating agents in the formation of the diffuse amyloid deposits that precede the formation of the neuritic plaque in the brain of patients affected with Alzheimer's disease.