Alzheimer's Development And Progression Seen Through New Imaging Agents
September 20, 2013

Fluorescent Agent Could Help Experts Watch Progression Of Alzheimer’s Disease

redOrbit Staff & Wire Reports - Your Universe Online

Researchers have created a new class of imaging agents that could allow them to view the biological processes that occur in the brain during the development and progression of Alzheimer’s disease, according to research appearing in Wednesday’s edition of the journal Neuron.

Senior author Dr. Makoto Higuchi of the National Institute of Radiological Sciences in Japan and colleagues have developed a fluorescent compound that allows them to visualize tau protein aggregates, a pathological hallmark of Alzheimer’s and other neurodegenerative conditions, directly in the brains of living patients.

Their work could provide a powerful tool to help in diagnosing the disorder, monitoring how effective treatments are, and testing potential new preventative and therapeutic agents in the near future.

According to the research team, tau proteins gather together and become entangled in the brains of patients with Alzheimer’s disease, while fragments of a second protein (amyloid beta) accumulate into deposits or plaques. Tau protein tangles are considered an important marker of neurodegeneration in Alzheimer’s, as well as an essential marker in other types of these diseases – tauopathies that do not involve amyloid beta plaques.

Dr. Higuchi’s team developed a fluorescent compound that binds to tau proteins (known as PBBS) and used them in positron emission tomography (PET) tests. By doing so, they were able to correlate the spread of tau tangles in the patient’s brain with moderate progression of Alzheimer's disease, they added.

“PET images of tau accumulation are highly complementary to images of senile amyloid beta plaques and provide robust information on brain regions developing or at risk for tau-induced neuronal death. This is of critical significance, as tau lesions are known to be more intimately associated with neuronal loss than senile plaques,” Dr. Higuchi said, adding that the discovery could be helpful for diagnosing and treating other neurological conditions.

Dr. Eric Karran, director of research at Alzheimer's Research UK, told BBC News that the study was “promising… with new drugs in development designed to target tau, scans capable of visualizing the protein inside the brain could be important for assessing whether treatments in clinical trials are hitting their target. If this method is shown to be effective, such a scan could also be a useful aid for providing people with an accurate diagnosis, as well as for monitoring disease progression.”

In related news, researchers from the University of Florida and their associates announced Thursday that they would receive up to $7.7 million in funding from the National Institutes of Health (NIH) over the next five years in order to find therapies for Alzheimer’s disease. The grant, which is part of a $45 million NIH initiative to study the neurodegenerative condition, will use large human and animal data sets to speed up the search for a cure.

“There is a huge unmet need with Alzheimer’s disease,” Dr. Todd Golde, director of the UF Center for Translational Research in Neurodegenerative Medicine, said in statement. “The economic costs for Alzheimer’s disease are now higher than those of heart disease and cancer, and as there are no therapies that modify the course of the disease, this is a devastating disorder for both patients who suffer from it and their families. With this grant, we hope to accelerate the discovery of possible disease-modifying therapies.”

“During the first year of the NIH grant, they plan to generate RNA sequences for every gene expressed in the human brain using 700 brain samples from 350 subjects. Then they will have data to compare with similar work done in mouse models to see where similarities and differences might be found,” the university said. “The investigators will focus on how genetic alterations to the innate immune system – the cells and mechanisms the body uses to fight potential microscopic invaders – may be implicated in Alzheimer’s disease.”