Patterns of gliosis in Alzheimer's disease and aging cerebrum

The distribution of astrocytic gliosis in Alzheimer's disease (AD) and aging cerebrum, as marked by immunoperoxidase staining for glial fibrillary acidic protein (GFAP), was examined in whole-hemisphere coronal sections. Cortical gliosis in AD had an obvious laminar pattern. There were two heavy bands of staining, one in layers II-III and another in layer V. Normal aging cases sometimes displayed considerable cortical gliosis, but no specific patterns were apparent. Most AD cases, and some normal aging cases, displayed hypertrophy of immunoreactive astrocytes at grey matter-white matter interfaces, especially the cortico-medullary junction. Subcortical grey matter gliosis was common in both normal aging and AD, but there was no consistent pattern in either group. The deep cerebral white matter, which is stained evenly and heavily in young, healthy individuals, showed uneven staining in both normal elderly and AD brains. In both AD and aging, perivascular gliosis was prominent throughout the cerebrum and especially in the putamen. In conclusion, both AD and aging cerebri show extensive gliosis: AD cortical gliosis has a specific laminar pattern, but there does not appear to be an AD-specific pattern of subcortical gliosis.