Fig. 5.

Exosomal proteins are enriched in human amyloid plaques. Paraffin-embedded human autopsy tissues from patients with AD or Parkinson's disease or from controls were studied. We performed either Gallyas silver stain and subsequent immunochemistry for Alix on hippocampal sections (d–f) or immunochemistry with hematoxylin counterstain only (a–c). Alix was stained by indirect alkaline phosphatase method with new fuchsin as the chromogen. (Magnification, ×63.) (a and d) Hippocampus of a normal control brain without amyloid plaques or detection of Alix. (b and e) Hippocampus of a patient with Parkinson's disease displaying slight accumulation of pathological tau-filaments but no amyloid plaques and no Alix. (c and f) Hippocampus of a patient with moderate to advanced Alzheimer's pathology [CERAD (Consortium to Establish a Registry for Alzheimer's Disease) score B] with discrete deposits of Alix within typical neuritic plaques (f) containing amyloid, hyperphosphorylated tau-fibrils, and cellular elements (astrocytes and microglia).