Co-localization of β-peptide and phosphorylated tau in astrocytes in a patient with corticobasal degeneration

The co-localization of amyloid beta (A beta) and phosphorylated tau in astrocytes in a patient with corticobasal degeneration is described. At autopsy, the present case exhibited neuropathological findings compatible with those of corticobasal degeneration, including atrophy of the frontal and temporal lobes, neuronal loss and gliosis in the cortical and subcortical regions, and presence of cortical ballooned neurons and astrocytic plaques. Moreover, many senile plaques were found in the cerebral cortex. There were also clusters of A beta-positive granules associated with astrocytic cytoplasm and processes in the subiculum and entorhinal cortex. In the entorhinal cortex, the A beta-positive granules were occasionally co-localized with phosphorylated tau-positive fibrillary structures in the astrocytic cytoplasm. To our knowledge, this is the first demonstration of co-localization of A beta and phosphorylated tau in astrocytes. This phenomenon implies that phagocytosis of A beta coincides with production of phosphorylated tau in the same reactive astrocytes.