Stage-dependent and sector-specific neuronal loss in hippocampus during Alzheimer's disease

Recent stereological studies documented a severe loss of hippocampal neurons in end-stage Alzheimer's disease. The development of the disease, however, is progressive and slow, over clinically inconspicuous decades. The Braak-staging system distinguishes six histopathological stages some of which are not accompanied by clinical symptoms. We analyzed hippocampal cell loss in correlation to Braak stages. Neuron numbers were determined with unbiased stereological principles in a defined subportion of the hippocampus of 28 subjects. There were no age-dependent neuronal losses in any of the hippocampal subdivisions examined. Compared to stage I, pyramidal cell loss in CA1 was reduced by 33% in s…