Oral glucose tolerance testing to modulate plasma amyloid levels: A novel biomarker

Esther S Oh; Christopher M Marano; Jeannie-Marie Leoutsakos; Rebecca W Lee; Robert A Rissman; Gwenn S Smith; Suzanne Craft; Constantine G Lyketsos

doi:10.1016/j.dadm.2015.06.002

Oral glucose tolerance testing to modulate plasma amyloid levels: A novel biomarker

Alzheimers Dement (Amst). 2015 Sep;1(3):311-315. doi: 10.1016/j.dadm.2015.06.002.

Authors

Esther S Oh¹, Christopher M Marano², Jeannie-Marie Leoutsakos³, Rebecca W Lee⁴, Robert A Rissman⁵, Gwenn S Smith², Suzanne Craft⁶, Constantine G Lyketsos²

Affiliations

¹ 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.
² Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
³ Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA ; Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
⁴ Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
⁵ Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA.
⁶ Department of Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA.

Abstract

Introduction: 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).

Discussion: OGTT combined with measures of plasma Aβ40 and 42 is potentially useful in distinguishing aging individuals who are in different stages of AD.

Keywords: Alzheimer's disease; blood biomarker; oral glucose tolerance test.

Abstract

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