title: Early initiation of hormone therapy in menopausal women is associated with increased hippocampal and posterior cingulate cholinergic activity.
abstract: BACKGROUND
  The role of ovarian hormones in maintaining neuronal integrity and cognitive function is still debated. This study was undertaken to clarify the potential relationship between postmenopausal hormone use and the cholinergic system.
  
  
  OBJECTIVE
  We hypothesized that early initiated hormone therapy (HT) preserves the cholinergic system and that estrogen therapy (ET) would be associated with higher levels of acetylcholinesterase activity in the posterior cingulate cortex and hippocampus compared to estrogen plus progestin therapy (EPT) or no HT.
  
  
  METHODS
  We conducted a cross-sectional study at a university teaching hospital.
  
  
  METHODS
  Fifty postmenopausal women (age, 65.2 ± 0.7 yr) with early long-term HT (n = 34; 13 ET and 21 EPT) or no HT (n = 16) participated in the study.
  
  
  METHODS
  There were no interventions.
  
  
  METHODS
  We measured cholinergic activity (acetylcholinesterase) in the hippocampus and posterior cingulate brain regions as measured by N-[(11)C]methylpiperidin-4-yl propionate and positron emission tomography as a marker of cholinergic function.
  
  
  RESULTS
  Significant effects of treatment on cholinergic activity measures were obtained in the left hippocampus (F = 3.56; P = 0.04), right hippocampus (F = 3.42; P = 0.04), and posterior cingulate (F = 3.76; P = 0.03). No significant effects were observed in a cortical control region. Post hoc testing identified greater cholinergic activity in the EPT group compared to the no-HT group in the left hippocampus (P = 0.048) and posterior cingulate (P = 0.045), with a nonstatistically significant trend in the right hippocampus (P = 0.073).
  
  
  CONCLUSIONS
  A differential effect of postmenopausal ET and EPT on cholinergic neuronal integrity was identified in postmenopausal women. The findings are consistent with a preservation of cholinergic neuronal integrity in the EPT group.
authors.affiliation: Department of Obstetrics and Gynecology, University of Michigan Health Systems, 1500 East Medical Center Drive, Room L4224 Women's Hospital, Ann Arbor, Michigan 48109-0276, USA. ysmith@umich.edu
authors.forename: Yolanda R
authors.initials: YR
authors.lastname: Smith
authors.forename: Luvina
authors.initials: L
authors.lastname: Bowen
authors.forename: Tiffany M
authors.initials: TM
authors.lastname: Love
authors.forename: Alison
authors.initials: A
authors.lastname: Berent-Spillson
authors.forename: Kirk A
authors.initials: KA
authors.lastname: Frey
authors.forename: Carol C
authors.initials: CC
authors.lastname: Persad
authors.forename: Nancy K
authors.initials: NK
authors.lastname: Reame
authors.forename: Robert A
authors.initials: RA
authors.lastname: Koeppe
authors.forename: Jon-Kar
authors.initials: JK
authors.lastname: Zubieta
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism*; D000367:Age Factors; D000368:Aged; D015914:Estrogen Replacement Therapy / Q000379:methods*; D004967:Estrogens / Q000627:therapeutic use*; D004966:Estrogens, Conjugated (USP) / Q000627:therapeutic use*; D005260:Female; D006179:Gyrus Cinguli / Q000187:drug effects* / Q000201:enzymology; D006624:Hippocampus / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D008593:Menopause / Q000187:drug effects* / Q000378:metabolism; D008875:Middle Aged
chemical_list: D004967:Estrogens; D004966:Estrogens, Conjugated (USP); D000110:Acetylcholinesterase