Abstract Details

Title Imaging microglial/macrophage activation in the early stage of Alzheimer's disease: a PET study using [18F]DPA-714 coupled with PiB.

Topic

Presentation(s) (-)

Poster/Presentation
Number 002

Objective

Background Neuroinflammation is thought to play a crucial role in the early stages of Alzheimer’s Disease (AD). 18 kDa Translocator Proteinis is up-regulated during inflammatory processes that may occur in neurodegenerative diseases

Design/Methods Twenty AD patients, as defined by a typical progressive amnesic deficit of the hippocampal type and a positive [11C]-PiB PET (13 at an early stage and 7 at dementia stages) where compared to 19 healthy controls with negative amyloid PiB-PET imaging. All subjects underwent a [18F]DPA?714 PET imaging. Anatomic segmentation of MRI provided values of [18F]DPA?714 fixation in 76 anatomical regions, using cerebellum as pseudo reference region. Analyses of the TSPO polymorphism showed that 34 subjects were high (HAB) or mixed (MAB) binders, forming the TSPO+ group (HAB: 6 controls; 8 AD; MAB: 9 controls, 11 AD) while 5 were low binders (TSPO-: 4 control, 1 AD).

Results Compared to normal controls, TSPO+ AD patients showed increased [18F]DPA?714 uptake: the global cortical uptake was 1.44±0.20 in HAB-AD patients versus 1.24±0.15 in HAB-controls (p<0.0001) and 1.41±0.25 in MAB-AD versus 1.35±0.28 in MAB-controls. The highest increase was found in the parietal, precuneus and posterior cingular regions (mean increase of +20 and +8% in both HAB and MAB). The [18F]DPA?714 uptake of the AD patients at the early stage was intermediate between controls and dementia-AD groups, reaching significant difference between the three groups for the HAB-subjects. No differences were found in the AD and controls TSPO low binders.

Conclusions Using [18F]DPA-714 in PET, neuroinflammatory changes was observed in AD, even at the early stage of the disease. DPA PET imaging could become therapeutic markers for the assessment of novel treatments.

Authors/Disclosures
Lorraine Hamelin (Pr Marie Sarazin)	No disclosure on file

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