Immunocytochemical localization of PHF-TAU in clinically diagnosed non-demented aged human brain - abstract

ABSTRACT

Paired helical filament (PHF), a molecular component of Alzheimer's Neurofibrillary Tangles, was immunocytochemically detected in clinically non-demented human brain. Brains from both sexes were examined. Cryostat cut sections from the cerebral hemisphere were stained with antibodies raised against PHF and TAU, and Thioflavine-D and examined with a microscope (Riechert-Jung), equipped for light and fluorescence transmission viewing. Several regions of the cerebral hemisphere reacted positively to all antibodies used and Thioflavine-S. Neurons in the stratum pyramidale of the hippocampus in all brains showed consistent and significant staining profiles. PHF-TAU molecules were observed in the cytoplasm and axoplasm of a large population of stratum pyramidale neurons. In some neurons, the entire cytoplasm and axoplasm were invaded by these molecules. PHF-TAU molecules also appeared in the adventitia of small blood vessels in the hippocampus and to a lesser extent in blood vessels of other regions. It was not possible to delineate or identify whether these vascular associated PHF-TAU molecules were present in perivascular nerve or glial processes or in the extracellular space. This may be the first indication that perivascular astrocytic processes may sequester PHF-TAU molecules. The hippocampus has been reported to be implicated in both long- and short-term memory. The present study has shown that neurons in the stratum pyramidale are structurally and metabolically affected by PHF-TAU molecules which may be the most important cause of cell damage, thus propagating memory impairment. It is not known what role the vascular associated molecules play in the pathology of Alzheimer's disease (AU)