title: Oral glucose tolerance testing to modulate plasma amyloid levels: A novel biomarker.
abstract: BACKGROUND
  Plasma levels of amyloid-beta (Aβ) do not correlate well with different stages of Alzheimer's disease (AD) in cross-sectional studies. Measuring the changes in Aβ plasma levels with an acute intervention may be more sensitive to distinguishing individuals in earlier stages of AD (mild cognitive impairment; MCI) from normal controls.
  
  
  METHODS
  57 participants (18 with AD/MCI and 39 cognitively normal controls) underwent oral glucose tolerance testing (OGTT). Blood samples were obtained over a 2 hour time period. Changes in plasma Aβ40 and42 levels were measured from either baseline or 5 minutes to the 10 minute time point.
  
  
  RESULTS
  Compared to normal controls, subjects with AD/MCI had significantly less change (Δ) in plasma levels for both Aβ40(-3.13(40.93)pg/ml vs. 41.34(57.16)pg/ml;p=0.002) and Aβ42(-0.15(3.77)pg/ml vs. 5.64(10.65)pg/ml; p=0.004).
  
  
  CONCLUSIONS
  OGTT combined with measures of plasma Aβ40 and 42 is potentially useful in distinguishing aging individuals who are in different stages of AD.
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA ; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA ; Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA ; Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Esther S
authors.initials: ES
authors.lastname: Oh
authors.affiliation: Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Marano
authors.affiliation: Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA ; Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Jeannie-Marie
authors.initials: JM
authors.lastname: Leoutsakos
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Rebecca W
authors.initials: RW
authors.lastname: Lee
authors.affiliation: Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Rissman
authors.affiliation: Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Gwenn S
authors.initials: GS
authors.lastname: Smith
authors.affiliation: Department of Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Craft
authors.affiliation: Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Constantine G
authors.initials: CG
authors.lastname: Lyketsos
keywords: Alzheimer's disease; blood biomarker; oral glucose tolerance test