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Researchers successfully tested a vaccine that targets a protein that builds up in the brains of people affected by Alzheimer’s. The vaccine has so far been tested only a mice but the researchers hope that their highly positive results will help them receive fundings for a clinical trial involving humans soon.

Finally, a vaccine for Alzheimer’s disease?

After a certain age, the human brain starts to shrink considerably but surprisingly, not too many neurons die in the process. In the Alzheimer’s diseased brain, however, many neurons stop functioning, lose connections with other neurons, and eventually die. The progressive disorder is the main cause of dementia and affects a third of senior citizens, or roughly 43 million people worldwide.

In the early stage, the damage is confined to the entorhinal cortex and hippocampus, two areas associated with memory, navigation, and perception of time. This sort of degeneration leads to memory loss and disorientation associated with the condition — though it has to be noted that Alzheimer’s starts damaging brain cells well before the first symptoms kick in.

Alzheimer’s disease is widely believed to be caused by the accumulation of beta-amyloid proteins which clump together to form plaques between neurons and disrupt cell function. Another physical characteristic of the Alzheimer’s diseased brain is the buildup of tau proteins, which tangle inside neurons, blocking their transport system.

Since 2013, researchers at the University of New Mexico (UNM) led by Dr. Kiran Bhaskar have been working on a vaccine that targets tau proteins, in the hope that it might prevent the progression of Alzheimer’s.

The vaccine was used on a group of mice that had Alzheimer’s-like symptoms. The vaccine’s antibodies seem to have cleared out pathological tau which tangles the brains of patients with Alzheimers’ disease. This response lasted for months, the researchers reported in the journal NPJ Vaccines.

Tau proteins are normally a stabilizing structure in the brain — it’s the long tangles that disrupt the ability of neurons to communicate with one another.

“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,” said Nicole Maphis, a Ph.D. candidate in UNM’s Biomedical Sciences Graduate Program.

In order to determine the vaccine’s efficacy, the researchers had mice go through maze-like tests. The rodents that received the vaccine were significantly better at navigating the mazes than those that didn’t receive the vaccine.

Scientists had also used monkeys and rabbits in their testing and hope to soon to validate the vaccine on humans if they receive enough funding. It’s common for drugs that work on mice or other animals not to have the same effect in humans, so a healthy dose of skepticism is advised.

“We have to make sure that we have a clinical version of the vaccine so that we can test in people,” Bhaskar said.