Memory-preserving particles could form part of an Alzheimer's vaccine puzzle
Alzheimer's is a disease with a number of potential causes and therefore a number of potential targets for prevention. One of those centers on a protein call tau, which can gather in long tangles that kill off neurons in the brain. Scientists have developed what they describe as a vaccine to keep the brain clear of these dangerous clumps, and found that treating mice in this way helped stave off the kind of memory decline associated with the disease.
Tau along with another protein called amyloid beta are thought to be significant players in the onset of Alzheimer's disease. Both can build up in clumps that impair cognitive function, with a large number of research endeavors focusing on ways to intervene in their harmful accumulation.
In the case of tau, it is a protein that in a healthy subject actually serves to stabilize the structure within the neurons. But in the brains of Alzheimer's patients, they are often found to have formed in abnormal clumps known as neurofibrillary tangles that play a much more destructive role.
Scientists at the University of New Mexico (UNM) have now come up with a way to scrub the brain clear of these tau tangles in mice. They've developed a new type of vaccine based on virus-like particles (VLPs), which are viruses engineered to have their genomes removed so they can't reproduce, but can trigger an immune response as the body still sees them foreign invaders.
In experiments on mice that had been bred to develop Alzheimer's-like symptoms, this vaccine prompted the animals to generate antibodies that cleared the tau proteins away, with its effects still seen months later. The team's testing involved subjecting the mice to a series of maze-like exercises to test their memory, with the vaccinated animals performing "remarkably" better than the others.
MRI scans revealed those vaccinated also underwent less brain shrinkage, a sign that less neurons had died off. The same group of mice exhibited significantly fewer tangles in the cortex and hippocampus regions of the brain, which are largely associated with learning and memory and deteriorate as a result of Alzheimer's disease.
"These results confirm that targeting tau tangles using a vaccine intervention could rescue memory impairments and prevent neurons from dying," says Nicole Maphis, a PhD candidate in UNM's Biomedical Sciences Graduate Program.
The researchers themselves note that turning this discovery into an actual vaccine for humans could take decades and millions of dollars, but they are nevertheless exploring the possibilities around commercialization. If nothing else, the work shines yet another sliver of light on the insidious workings of an incredibly complex and poorly understood neurological disease, and offers yet another pathway for exploration in our efforts to stop it in its tracks.
A paper describing the work was published in the journal NPJ Vaccines.
Source: University of New Mexico