The Relationship of Plasma Transthyretin Level with Global or Regional Amyloid Beta Burden in Subjects with Amnestic Mild Cognitive Impairment: Cross-Sectional Amyloid PET Study.

ABSTRACT

Background: To investigate the relationships of plasma transthyretin levels with amyloid beta deposition and medial temporal atrophy in amnestic mild cognitive impairment. Methods: This is a cross-sectional study of association of subjects with amnestic mild cognitive impairment. Plasma transthyretin levels, brain magnetic resonance imaging, and 18F-florbetaben positron emission tomography were simultaneously measured in subjects with amnestic mild cognitive impairment. Results: Plasma transthyretin levels were positively associated with amyloid beta deposition in global (r = 0.394, P = .009), frontal cortex (r = 0.316, P = .039), parietal cortex (r = 0.346, P = .023), temporal cortex (r = 0.372, P = .014), occipital cortex (r = 0.310, P = .043), right posterior cingulate (r = 0.350, P = .021), left precuneus (r = 0.314, P = .040), and right precuneus (r = 0.398, P = .008). No association between plasma transthyretin level and medial temporal sub-regional atrophies was found. Conclusions: Our findings of positive association of plasma transthyretin levels with global and regional amyloid beta burden suggest upregulation of transthyretin level as a reactive response to amyloid beta deposition during the early stages of the Alzheimer's disease process.