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

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).

Background

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 beenunsuccessful due to late diagnosis.

• Addressing a Critical Unmet Need:

We need a Biomarker for early prediction of AD, prior to theaggregation of Amyloid plaques, tau pathology, synapsedegeneration, neuron loss, and deterioration of cognitivefunction.

• Significance:Early AD detection can facilitate drug discovery andtherapeutic efforts and potentially lead to successfuldiagnosis and prevention of AD

Hypothesis

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

AIMS:

1. Development and characterization of a novelPET radioligand for detection of Ab oligomers

1. Determining the relationship of Ab oligomersin brain with other AD pathology

1. Algorithm for identifying at-risk individuals,

human toxicity screen and PET trials

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

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)

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

Cost and Resource Use

Funding request: $500,000/year for 3 years

Y1: Radiotracer developmentCore 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

Salary

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

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.

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,