title: Effects of long-term, low-dose sex hormone replacement therapy on hippocampus and cognition of postmenopausal women of different apoE genotypes.
abstract: OBJECTIVE
  To study the effects of long-term, low-dose sex hormone replacement therapy (HRT) on the volume and biochemical changes of the hippocampus in postmenopausal women carrying apolipoprotein E (apoE) gene epsilon3 or epsilon4.
  
  
  METHODS
  Eighty-three postmenopausal women who had used a low dose of HRT for over 4 years were selected as the HRT group, and 99 postmenopausal women with matched age and education were enrolled as the control group. ApoE alleles were analyzed by PCR. Magnetic resonance imaging was performed to determine the volume of the brain hippocampus. Proton magnetic resonance spectroscopy was used to detect the biochemical changes in the anterior cingulate cortex and hippocampus in apoE epsilon4 and epsilon3 carriers. Six common cognitive tests were used to make an overall evaluation of cognitive function.
  
  
  RESULTS
  Analysis with the apoE epsilon4 carriers showed that the volume of the hippocampus of the control group were significantly lower than those of the HRT group. The biochemical analysis showed that there was an increase of N-acetylaspartate (NAA)/total creatine (tCr) and a decrease of myoinositol (mI)/tCr in the hippocampus of apoE epsilon4 carriers in the HRT group, compared with the control group. For the apoE epsilon3 carriers, the least squares means (LSMEAN) of the HRT group was higher than that of the control group.
  
  
  CONCLUSIONS
  This study showed that long-term, low dose HRT might be beneficial for reducing the risk of AD development in vulnerable postmenopausal women. Meanwhile, HRT could increase the LSMEAN of apoE epsilon3 carriers.
authors.affiliation: School of Basic Medicine, Peking Union Medical College and Institute of Basic Medical Science, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Yue
authors.forename: Ling
authors.initials: L
authors.lastname: Hu
authors.forename: Qin-jie
authors.initials: QJ
authors.lastname: Tian
authors.forename: Jing-mei
authors.initials: JM
authors.lastname: Jiang
authors.forename: Yi-long
authors.initials: YL
authors.lastname: Dong
authors.forename: Zheng-yu
authors.initials: ZY
authors.lastname: Jin
authors.forename: Yu-hang
authors.initials: YH
authors.lastname: Cheng
authors.forename: Xia
authors.initials: X
authors.lastname: Hong
authors.forename: Qin-sheng
authors.initials: QS
authors.lastname: Ge
authors.forename: Ping-ping
authors.initials: PP
authors.lastname: Zuo
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000517:prevention & control; D001057:Apolipoproteins E / Q000235:genetics*; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000032:analysis; D003071:Cognition; D003404:Creatinine / Q000032:analysis; D003430:Cross-Sectional Studies; D015914:Estrogen Replacement Therapy; D005838:Genotype; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007294:Inositol / Q000032:analysis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017698:Postmenopause; D012189:Retrospective Studies
chemical_list: D001057:Apolipoproteins E; D001224:Aspartic Acid; D007294:Inositol; C000179:N-acetylaspartate; D003404:Creatinine