About this Journal Submit a Manuscript Table of Contents
Journal of Neurodegenerative Diseases
Volume 2013 (2013), Article ID 531326, 9 pages
http://dx.doi.org/10.1155/2013/531326
Research Article

Sex Differences in Presynaptic Density and Neurogenesis in Middle-Aged ApoE4 and ApoE Knockout Mice

Department of Anatomy, Donders Centre for Neuroscience, Radboud University Nijmegen Medical Centre, Geert Grooteplein 21, 6525 EZ Nijmegen, The Netherlands

Received 16 November 2012; Accepted 2 January 2013

Academic Editor: Barbara Picconi

Copyright © 2013 A. Rijpma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Atherosclerosis and apolipoprotein E ε4 (APOE4) genotype are risk factors for Alzheimer’s disease (AD) and cardiovascular disease (CVD). Sex differences exist in prevalence and manifestation of both diseases. We investigated sex differences respective to aging, focusing on cognitive parameters in apoE4 and apoE knockout (ko) mouse models of AD and CVD. Presynaptic density and neurogenesis were investigated immunohistochemically in male and female apoE4, apoE ko, and wild-type mice. Middle-aged female apoE4 mice showed decreased presynaptic density in the inner molecular layer of the dentate gyrus of the hippocampus. Middle-aged female apoE ko mice showed a trend towards increased neurogenesis in the hippocampus compared with wild-type mice. No differences in these parameters could be observed in middle-aged male mice. Specific harmful interactions between apoE4 and estrogen could be responsible for decreased presynaptic density in female apoE4 mice. The trend of increased neurogenesis found in female apoE ko mice supports previous studies suggesting that temporarily increased amount of synaptic contacts and/or neurogenesis is a compensatory mechanism for synaptic failure. To our knowledge, no other studies investigating presynaptic density in aging female apoE4 or apoE ko mice are available. Sex-specific differences between APOE genotypes could account for some sex differences in AD and CVD.