title: 3alpha,5alpha-THP: a potential plasma neurosteroid biomarker in Alzheimer's disease and perhaps non-Alzheimer's dementia.
abstract: BACKGROUND
  A plasma biomarker for neurodegenerative disease is desirable because blood is relatively simple to obtain compared with other biological samples such as cerebrospinal fluid. Recent literature suggests that neurosteroid metabolism may be altered in Alzheimer's disease (AD).
  
  
  OBJECTIVE
  We sought to measure the plasma levels of seven steroids to assess their potential as biomarkers for dementia and AD.
  
  
  METHODS
  Steroids were measured using validated radioimmunoassay methods in AD (n=15), non-AD dementia (n=4), and control subjects (n=20). Demented subjects were in the mild-to-moderate stages of illness. Measurements were done blind to subject status in an independent laboratory.
  
  
  RESULTS
  The notable finding was the significantly lower 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP) level in demented subjects compared with controls (25% decrease; p=0.004); 3alpha,5alpha-THP was the only one of the steroids demonstrating an effect of dementia.
  
  
  CONCLUSIONS
  Lowered 3alpha,5alpha-THP levels appear promising as a biomarker in dementia, but further work is needed to establish the sensitivity and specificity of these findings in AD.
authors.affiliation: Department of Neurology, University of Kentucky Medical Center, Lexington, KY 40536-0098, USA. csmith@mri.uky.edu
authors.forename: Charles D
authors.initials: CD
authors.lastname: Smith
authors.forename: David R
authors.initials: DR
authors.lastname: Wekstein
authors.forename: William R
authors.initials: WR
authors.lastname: Markesbery
authors.forename: Cheryl A
authors.initials: CA
authors.lastname: Frye
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D003704:Dementia / Q000097:blood*; D004958:Estradiol / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D011280:Pregnanolone / Q000097:blood*; D011374:Progesterone / Q000097:blood; D045165:Testosterone Congeners / Q000097:blood
chemical_list: D015415:Biomarkers; D045165:Testosterone Congeners; D011374:Progesterone; D004958:Estradiol; D011280:Pregnanolone