Increased expression of estrogen receptor alpha and beta in the nucleus basalis of Meynert in Alzheimer's disease

The human nucleus basalis of Meynert (NBM) is severely affected in Alzheime r's disease (AD). Since estrogens may reduce both the risk and severity of AD, possibly by an action on the cholinergic system, we determined whether estrogen receptors are present in the human NBM and what their changes are in normal aging and in AD. ER alpha was expressed to a higher degree than E R alpha and was localized mainly in the cell nucleus, while ER beta was mai nly confined to the cytoplasm. A significant positive correlation between t he percentage of ER alpha nuclear positive neurons and age was found in men but not in women, whereas the proportion of ER beta cytoplasm positive cel ls increased during aging in both sexes. In AD the proportion of neurons sh owing nuclear staining for both ER alpha and beta and cytoplasmic staining for ER beta was markedly increased. The percentage of ER beta nuclear posit ive neurons increased in AD only in women but not in men. The ApoE genotype had no effect on ER expression in the NBM in AD. In conclusion, whereas on ly minor sex- and age-related changes in both ERs were found in the human N BM, a clear upregulation of ER alpha and beta was observed in AD. (C) 2001 Elsevier Science Inc. All rights reserved.