Reduced cerebrospinal fluid estradiol levels are associated with increasedbeta-amyloid levels in female patients with Alzheimer's disease

Recent in-vitro studies indicate that estrogens such as 17 beta -estradiol (E-2) may decrease the production of beta -amyioid 1-2 (A beta 42), a pepti de central for the formation of senile plaques in Alzheimer's disease (AD). To test this hypothesis in a clinical study, cerebrospinal fluid levels of E-2 were compared between 30 female AD patients and 11 female patients wit h non-dementing diseases such as major depression and investigated with res pect to beta -amyloid 1-40 and A beta 42 levels. E-2 levels were significan tly (P < 0.05) lower in the AD group than in controls; within the AD group E-2 levels were inversely correlated with A<beta>42 concentrations (r= -0.3 6, P = 0.05). This is the first clinical study providing evidence for an in fluence of E-2 on A beta 42 metabolism in vivo. This observation correspond s to the putative beneficial effects of estrogen replacement therapy on the development and course of AD. (C) 2001 Elsevier Science Ireland Ltd. All r ights reserved.