Developing New Tracers for Imaging Synapses in the Brain

Study Rationale:
A synapse is a point of contact between a nerve cell and another cell that allows them to communicate. In the brain, changes in the number of synapses (synaptic density) are associated with neurological and psychiatric diseases. The development of brain tracers -- chemicals that visualize the function and structure of the brain -- for positron emission tomography (PET) imaging can help diagnose neurodegenerative disorders and test new therapies that target synapses. An existing brain tracer can detect synaptic changes in people with neurodegenerative diseases but has its limitations. In the present study, we will develop new and improved tracers for brain imaging in Parkinson's disease and several other brain disorders.

Hypothesis:
We hypothesize that new brain tracers with 18F -- a radioactive molecule -- attached to them will be better than the existing brain tracer. If this is indeed the case, these new tracers will find a wide clinical use.

Study Design:
In this study, we will create three new brain tracers with attached 18F. We will then measure their performance by conducting PET imaging in pre-clinical models to identify the best of the three. Next, we will test the best tracer by assessing the radiation its 18F produces and its side effects in pre-clinical models. And finally, we will request the permission to conduct a human clinical trial in the United States and Canada.

Impact on Diagnosis/Treatment of Parkinson's Disease:
With a tracer that accurately measures synaptic density, researchers will be able to select the best therapeutic candidates. The tracer would also be valuable in determining whether synaptic density is a biomarker -- objective measure -- of Parkinson's disease.

Next Steps for Development:
The tracer could be used in clinical research to measure synaptic density in the human brain. Furthermore, it could help identify the dose of PD drug candidates that target synaptic density.