New PET scan for Alzheimer's disease directly measures synaptic loss
Exciting new research from Yale University has revealed a new method that could potentially objectively diagnose if a person is suffering through the early stages of Alzheimer's disease using a non-invasive PET scan.
A major roadblock slowing down effective Alzheimer's research is our inability to easily, or clearly, diagnose the disease at its early stages. Several blood tests are being explored that can identify biomarkers signaling the early presence of the disease, but nothing has proved conclusive enough to move into general clinical use.
The new Yale University innovation uses PET imaging technology to evaluate cognitive decline by effectively measuring how much synaptic loss or degradation has occurred in a patient's brain. To quantify a person's "synaptic density" the researchers homed in on a protein called SV2A. This protein is found in nearly all healthy synapses, but as those connections degrade, so does the presence of SV2A.
Using a specific radioactive chemical that binds with, and illuminates, SV2A, the researchers were able to create PET scans that can objectively measure synaptic density in a variety of different brain regions. Initial tests using the method revealed patients with early stage Alzheimer's disease had up to 41 percent less SV2A markers in brain areas associated with memory, when compared to a healthy control group.
"We found that in early Alzheimer's disease, there is loss of synaptic density in the region of the hippocampus," says Ming-Kai Chen, first author on the newly published study. "With this new biomarker, PET imaging for SV2A, we can measure synaptic density in the living human brain."
As well as delivering clinicians a new and much needed diagnostic tool to evaluate prospective patients, the method will potentially revolutionize research into viable treatments for the disease. The ability to have an objective, and quantifiable, method that can accurately measure synaptic density will allow researchers to better evaluate the efficacy of new treatments and select appropriate candidates for clinical trials.
"A critical barrier in Alzheimer's research has been the inability to measure synaptic density in living individuals," says Christopher Van Dyck, director of the Yale Alzheimer's Disease Research Unit. "For those of us in the Alzheimer's field, in vivo assessment of synaptic density may transform our ability to track early Alzheimer's pathogenesis and response to treatment."
The next step in the research is to verify the method's accuracy over a larger cohort of patients. The research team also suggests this method should be applicable to a broad variety of diseases that involve synapse loss, from Parkinson's disease and epilepsy, to even depression or schizophrenia.
The study was published in the journal JAMA Neurology.