Citation and Abstract


Villemagne VL, Ellis KA, Chetelat G, Bourgeat P, Jones G, Salvado O, Martins R, Ames D, Masters CL, Rowe CC. Relation between Rates of Aβ Deposition, Apoe Genotype and Cognition: Results from-5 Year Longitudinal Study. Human Amyloid Imaging Abstract. 2012 Jan 1;

 
  ABSTRACT
Background: Longitudinal evaluation of ageing individuals is providing insight into the different factors leading to Alzheimer's disease (AD). In this study, we used longitudinal data from the AIBL cohort, to provide a better understanding of the relationship between Abdeposition and cognition in the development of AD.
Methods: One hundred and nineteen participants -74 elderly healthy controls (HC);9 Mild Cognitive Impairment (MCI) subjects; and6 mild AD patients - were evaluated at enrolment and8 and6 months later. On each visit, participants underwent neuropsychological examination, a MRI and a1C-PiB PET scan. Rates of change for Aβ deposition and cognitive decline were derived from the slope of the regression plots over-5 years and used in the correlational analysis.
Results: Aβ deposition (0.05±0.04 vs 0.01±0.03 SUVR/yr, p<0.0001) and memory decline (-0.17±0.29 vs -0.02±0.22 SD/yr, p=0.02) were significantly faster in PiB+ vs PiB- HC. Aβ deposition and memory decline were also faster in PiB+ than in PiB- MCI (0.05±0.01 vs 0.01±0.01 SUVR/yr, p=0.0004; and -0.21±0.05 vs -0.04±0.06 SD/yr, p=0.04, respectively). Aβ deposition was slightly slower in AD (0.03±0.03 SUVR/yr). Aβ deposition in ApoE e4 carriers was significantly faster only in the MCI group (R2=0.39, p=0.006). Cognitive decline was inversely associated with Aβ deposition in all groups: HC (R2=0.12, p=0.044), MCI (R2=0.23, p=0.023), and AD (R2=0.71, p=0.033).
Conclusions: Aβ deposition is associated with cognitive decline even in asymptomatic healthy controls. This supports the theory that Aβ deposition plays a fundamental role in the development of AD and suggests that to be effective, anti-Aβ therapy may need to be given early in the course of the disease, perhaps even before symptoms appear.