Scientists develop potential Alzheimer's vaccine, successfully treat mice

A team of researchers at the University of New Mexico is developing a new vaccine that they hope will be able to prevent Alzheimer's disease in humans after seeing promising results in tests with mice.

Alzheimer's is a progressive neurodegenerative disease that affects memory functioning and is characterized by cognitive decline. There are currently 43 million Alzheimer's sufferers worldwide, and instances are on the rise.

The research is being done in the lab of Kirin Bashkar, Ph.D. and associate professor in UNM’s Department of Molecular Genetics & Microbiology. Bashkar told KRQE-TV that he saw the lack of an Alzheimer's cure as a challenge and began seriously pursuing the development of a treatment in 2013.

"I would say it took about five years or so to get from where the idea generated and get the fully functioning working vaccine," Bashkar told KRQE-TV.

In a paper published in the NJP -Vaccines journal, the team reported that it had successfully created a virus-like protein that had promising results in treating mice that had been bred to develop symptoms similar to those experienced by human Alzheimer's patients.

The virus-like protein targets accumulations of another protein called tau. Though tau is supposed to function as a stabilizing structure inside of neurons, accumulation of tau creates long tangles that interfere with neurons' capabilities to communicate with one another, causing the memory problems that characterize Alzheimer's.

When researchers tested the virus-like protein on mice with Alzheimer's-like symptoms, they developed antibodies that cleared the tau protein from their brains. What's more: The results lasted for months afterward.

“We’re excited by these findings, because they seem to suggest that we can use the body’s own immune system to make antibodies against these tangles, and that these antibodies actually bind and clear these tau tangles,” said Nicole Maphis, a Ph.D. candidate in UNM’s Biomedical Sciences Graduate Program.

When Maphis challenged the mice with maze-like tests, those that had been treated with the vaccine performed significantly better than those that hadn't.

A small animal MRI was used to study the effectiveness of the protein-based vaccine on the prevention of brain atrophy in the vaccinated mice and found significantly less tangles in both the cortex and hippocampus, two areas of the brain that are crucial for learning and memory. They also discovered a distinct decrease in the loss of neurons and a lessening of hippocampal atrophy, which suggest that the vaccine is neuroprotective.

“These results confirm that targeting tau tangles using a vaccine intervention could rescue memory impairments and prevent neurons from dying,” Maphis said.

The vaccine was developed with the assistance of David Peabody and Bryce Chackerian, UNM scientists who helped pioneer the use of virus-like proteins to create vaccines for dengue virus, hepatitis B, and HPV.

Virus-like proteins are created by removing the genome of a virus so it cannot reproduce, leaving only a protein shell. The shell is still recognizable as an invasive threat to the human immune system, which creates antibodies that react to and neutralize the protein shell. In the case of the Alzheimer's vaccine, the virus-like protein triggers an immune response to target and destroy tau tangles.

The researchers believe that their method with this specific virus-like protein may be applicable to a wider range of tauopathies, including dementia, traumatic brain injury, and chronic encephalopathy (brain disease, damage, or malfunction).

Though getting a drug out of the lab phases of development and into actual human trials can takes decades and is often tremendously expensive, Bashkar is hopeful that necessary funding can be obtained to create a version of the vaccine that can be tested on humans.