Dementia Japan 26:285-291, 2012

Histopathology ofβ-amyloid under electron microscope in the brain with Alzheimer's disease

Taihei Miyakawa

Amakusa Hospital

    Electron microscopical observations of serial sections revealed that small blood vessels, were closely associated with the amyloid fibrils which formed the senile plaques and amyloid fibrils are formed at the basement membranes of small blood vessels.  Vascular feet of astroglial cells surrounding small blood vessels showed degenerative features, and many nerve cells in this area either were at different degrees of decomposition or appeared to be destroyed entirely.  Brain atrophy in AD is considered to be caused by the amyloid angiopathy of microvessels and degeneration of capillaries and vascular feet.  Amyloid fibrils forming the senile plaques consist of hollow rods composed of filaments arranged in a tightly coiled helix.  Each turn of the helix consisted of an array of five globular subunits.
    Our findings strongly suggest that a major causal mechanism of AD is some alteration of the blood-brain barrier.

Address correspondence to Dr. Taihei Miyakawa, Amakusa Hospital (5789 Saitsu, Amakusa City, Kumamoto 863-2171, Japan)