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, and18F-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.