This document proposes developing a novel PET radioligand to detect amyloid beta oligomers for early diagnosis of Alzheimer's disease. It describes 3 aims: 1) Develop and characterize radioligands to detect oligomers in transgenic rat models via microPET scans. 2) Determine the relationship between oligomer binding and AD pathology in rats. 3) Develop an algorithm to identify at-risk individuals and conduct toxicity screening and early human PET trials. The goals are to facilitate early diagnosis before symptom onset to allow for more effective treatment development.

1. Diagnosing Alzheimer's before
the Alzheimer's; Novel tools for
early detection
Nellie Byun, PhD
Romina Gentier, MSc
Rylan Allemang-Grand, BSc
Elizabeth Steuer, BSc
Jennifer Goldman, BA

2. Background
Oligomer Hypothesis
Synapse loss does not require the presence of amyloid deposition (Mucke et al., 2000).
Aβ oligomers are central nervous system neurotoxins which lead to disruptions in
synaptic plasticity (Lambert et al., 1998).
Aβ oligomers leads to synapse loss and disrupt glutamate receptor trafficking (Lacor et
al., 2007).

3. Problem:
Current diagnosis of AD relies on the denouement of
cognitive function and atrophy of cortical tissue, symptoms
predicting poor prognosis.
Experimental AD therapies have likely been
unsuccessful due to late diagnosis.

4. • Addressing a Critical Unmet Need:
We need a Biomarker for early prediction of AD, prior to the
aggregation of Amyloid plaques, tau pathology, synapse
degeneration, neuron loss, and deterioration of cognitive
function.
• Significance:
Early AD detection can facilitate drug discovery and
therapeutic efforts and potentially lead to successful
diagnosis and prevention of AD

5. Hypothesis
Accumulation of low molecular weight amyloid
fragments are an early predictor of AD and can be
detected by PET imaging.

6. AIMS:
1. Development and characterization of a novel
PET radioligand for detection of Ab oligomers
1. Determining the relationship of Ab oligomers
in brain with other AD pathology
1. Algorithm for identifying at-risk individuals,
human toxicity screen and PET trials

7. AIM 1:Development and characterization of a novel PET
radioligand for detection of ADDLs in MgGill-TG thy1-APP
rats
Strategy: Multiple antibodies (Abs) have already been developed
against Ab oligomers. In the cancer field, antibodies have been
successfully (i.e., FDA approved) utilized as imaging agents, so the
technology and expertise should be used in neuroscience.
Methods: Screening and validation
- Purchase Abs against oligomers (Nu-1, Nu-2, Nu-3, Nu-4) [See
Alzforum antibody list]
- Radiochemistry to label Abs with 18F and purify.
- Perform microPET scans in anesthetized MgGill-TG thy1-APP and
control rats; tail vein injection of 18F-Ab (0.75 and 1.5 mCi); n=
10/group
- Perform Nanotech Assay (Mirkin) following PET scan to quantify Ab
and determine sensitivity of PET ligands

8. AIM 2:
Determining the spatial and temporal relationship of Ab
oligomer binding in brain with AD pathology
• MgGill-TG thy1-APP rats housed in non-stressful
environments
• Behavior- Object Recognition, Morris Water Maze
• Immunochemistry and quantification of Abeta
aggregates, Tau pathology, synapse density, activated
microglia, cell density, neurite morphology, number of
neurons
• Electrophysiology: miniEPSCs, LTP/LTD measurements
(synapse density and plasticity measurements)

9. AIM 3:Algorithm to identify at-risk individuals, human
toxicity screen and PET trials
• Family history of AD
• APOE4
• Functional Test of olfactory dysfunction (U-Penn
Smell Identification Test)
• Body mass index
• Type II Diabetes
• History of Infection
• Oral Hygiene
• Exercise patterns
• Diet
Toxicity screen in humans
Early trials in familial AD before plaque pathology

10. Cost and Resource Use
Funding request: $500,000/year for 3 years
Y1: Radiotracer development
Core costs
-Animals and housing: $30,000 [$2/day/Cage]
-PET Radiochemistry: $16,000 [$100/animal ($600/synthesis
for n=6 animals)]
-microPET scanning: $40,000 [$240/animal ($120/hour, 2
hours)]
Supplies/Equipment
-UPSIT (Sold by Sensonics, Inc): $26.95/test

11. Translational Potential and Future Directions
• Algorithm for determination of risk Questionnaire
• Family History of AD
• Type-2 Diabetes
• Lifestyle (diet, stress, exercise)
• Decline in Olfactory function
• PET Scans

12. References
Mucke, L., Masliah, E., Yu, G.Q., Mallory, M., Rockenstein, E.M., Tatsuno, G., et al.
(2000). High-level neuronal expression of A-beta (1-42) in wild-type human
amyloid protein precursor transgenic mice: synaptotoxicity without plaque
formation. Journal of Neuroscience, 1;20(11), 4050-4058.
Lambert, M. P., Barlow, A. K., Chromy, B. A., Edwards, C., Freed, R., Liosatos, M.,
et al. (1998). Diffusible, nonfibrillar ligands derived from Abeta1-42 are potent
central nervous system neurotoxins. Proceedings of the National Academy of
Sciences of the United States of America, 95, 6448–6453.
Lacor, P. N., Buniel, M. C., Furlow, P. W., Clemente, A. S., Velasco, P. T., Wood,
M., et al. (2007). Abeta oligomer-induced aberrations in synapse composition,
shape, and density provide a molecular basis for loss of connectivity in
Alzheimer’s disease. Journal of Neuroscience, 27, 796–807.

13. Thank You!
• EURON, AHAF, ISAO
• Drs. Harry Steinbusch, Claudio Cuello, Mark
Mattson, William Klein, Bart Rutten, Paul
Coleman, Cindy Lemere, Frank LaFerla, Jochen
Walter, Jorg Bernard Schultz, Ilse
Dewachter, Carol Colton, Michael
Sofroniew, Jin-Moo Lee, Joana Palha,