Cell cycle-related protein expression in vascular dementia and Alzheimer'sdisease

Recent findings from our and other laboratories indicate that cell cycle-re lated phenomena may play a key role in the formation of Alzheimer-type path ology and neuronal cell death in both Alzheimer's and cerebro-vascular dise ases. In this study we examine the expression patterns of cyclins A, B1, D1 and E in neuronal nuclei in the hippocampus in autopsied healthy elderly i ndividuals, Alzheimer's disease patients and subjects suffering from cerebr ovascular disease with and without co-existing Alzheimer's disease. Nuclear cyclin B1 and cyclin E expression was detected in hippocampal neurones in each subject category. However, cyclin B1 expression was significantly elev ated in the CA1 of patients suffering from cerebro-vascular disease alone, while cyclin E. expression was significantly higher in the CA4 subfield in patients suffering from mixed Alzheimer's and cerebro-vascular diseases com pared to subjects in other categories. We hypothesize that cell cycle re-en try may occur in healthy elderly people leading to age-related cell death a nd mild Alzheimer-type pathology in the hippocampus. However, in pathologic al conditions, the cell cycle arrest may lead either to the development of severe Alzheimer-related pathology or to excess apoptotic cell death as in vascular dementia. (C) 1999 Elsevier Science Ireland Ltd. All rights reserv ed.