A quantitative analysis of human astrocytosis

The number of astrocytes in an atrophic human brain was counted with the aid of immunohistochemistry for glial fibrillary acidic protein. Microscopically, astrocytosis was remarkable in the cerebral neocortex and white matter. Taking the cortical atrophy into consideration, however, the total number of astrocytes in the cortical layers II – VI was not increased. The number of astrocytes in the white matter was not increased either. It is indicated that astrocytosis does not always mean hyperplasia (net increase of total number) of astrocytes.