A vaccine to prevent Alzheimer’s disease is a sort of holy grail in the Alzheimer’s research world. But so far efforts to develop a safe and effective Alzheimer’s vaccine have proven fruitless.
Now researchers at the University of New Mexico report they have developed an experimental vaccine that is showing promise in mice. The mice had been bred to develop a disease resembling Alzheimer’s disease in people, and they performed better in navigating mazes after receiving the vaccine, suggesting a boost in brain function.
The vaccine uses virus-like particles that stimulate the immune system to target tau, a protein that builds up in the dead and dying brain cells in those with Alzheimer’s disease. Tau forms long tangles that prevent communication between brain cells and choke off healthy brain cells, and tau tangles are one of the hallmarks of Alzheimer’s disease.
“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 PhD candidate in UNM’s Biomedical Sciences Graduate Program. “These results confirm that targeting tau tangles using a vaccine intervention could rescue memory impairments and prevent neurons from dying.”
The researchers found that when the vaccine was given to mice, they developed antibodies that cleared the tau protein from their brains – and the response lasted for months. When the animals were tested in a series of maze-like tests, mice receiving the vaccine performed remarkably better than those that hadn’t. MRI brain scans showed that the vaccinated animals had less brain shrinkage, suggesting that the vaccine prevented neurons from dying.
The mice also had significantly fewer tangles in both the cortex and the hippocampus, brain areas that are critical for learning and memory and that are progressively destroyed in Alzheimer’s disease. The findings were published in the journal NPJ Vaccines.
But caution is required in interpreting these results. Many drugs and vaccines that show promise in early animal testing fail to produce benefits in people. And some have proven deadly. A vaccine that showed early promise had undergone tests in people more than 10 years ago, for example, but some people developed serious brain inflammation after receiving it.
Still, researchers are excited by the prospect of an effective Alzheimer’s vaccine because it could be given to people at high risk for the disease to fend off future mental decline. It could also have benefits for those afflicted with the illness, particularly those in the earlier stages of disease, helping to prevent further memory loss and even possibly restore thinking abilities.
Much more testing on animals will be required before this or other vaccines in development are tested in people. So it will likely be many years, if ever, before an effective Alzheimer’s vaccine becomes available. Scientists still aren’t sure what causes Alzheimer’s disease, and are exploring many avenues of potential treatment.
The Fisher Center for Alzheimer’s Research Foundation continues to fund essential basic research into the underlying cases of Alzheimer’s disease, research that may one day prove key to finding a cure for an illness that affects more than five million Americans, and many more worldwide.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Nicole M. Maphis, Julianne Peabody, Erin Crossey, et al: “Qß Virus-like particle-based vaccine induces robust immunity and protects against tauopathy.” NPJ Vaccines. June 3, 2019