Alzheimer's disease – don't give up on plaque-busting drugs just yet

September 28, 2018 by Davide Bruno, The Conversation
Credit: VeronikaChe/Shutterstock.com

Alzheimer's disease is associated with a build-up of plaques in the brain called amyloid beta. These plaques are thought to lead to a loss of neurons, which then causes the classic symptoms of the disease – including memory loss. Most Alzheimer's drugs have been developed to either stop these plaques from forming or to help remove them.

Until recently, attempts at developing anti-amyloid drugs to treat Alzheimer's disease had been met with cautious optimism. Experiments in animal models of Alzheimer's disease have been successful, showing reductions in plaques. But when the same drugs were tested in humans, the results were disappointing. Symptoms of dementia did not go away, and memory did not improve.

This lack of positive results has been discouraging, not only for people with the condition and those close to them, but also for researchers, many of whom have called into question the accepted wisdom that the build-up of plaques is the cause of Alzheimer's disease.

As a result of these failed trials, some pharmaceutical companies have decided to stop research in this area. But this could be a rash move.

It is possible, in fact, that while anti-amyloid medications take away toxic plaques, they also cause side effects that cancel the benefits of removal. One of these side effects is that brain cells will fire excessively, a phenomenon known as neuronal hyperactivity.

Amyloid-beta plaque on a neuron. Credit: Juan Gaertner/Shutterstock.com
A winning drug combination?

We know that anti-amyloid drugs can cause the brain to become hyperactive. In other words, while the anti-amyloid drugs do their job of getting rid of plaques, they can also push neurons to work more than they normally would. Hyperactive neurons may then stop the new memories from forming or stop old ones from coming back.

So while anti-amyloid drugs eliminate what we think is the cause of Alzheimer's disease, their side effects bring on symptoms that are similar to those of dementia. The effects of hyperactivity can be especially bad in those brain areas that are already working overtime due to the effects of Alzheimer's disease, including some areas that contribute to the release of adrenaline in the body. But at this point, this is just a hypothesis based on animal research, and studies in humans are needed to confirm it.

The good news is that neuronal hyperactivity can be prevented and reduced with the help of other drugs. Combining anti-amyloid drugs with anti-hyperactivity drugs may ultimately prove to be an effective combination to treat this devastating disease. However, there is still a long way to go before an actual cure is on the table.

Despite a string of failed clinical trials for new dementia drugs, claims that a cure may be close have persisted. And there are reasons remain optimistic: the potential for combining anti-amyloid with anti-hyperactivity drugs is one of them.

Explore further: Can nanotechnology help treat Alzheimer's?

Related Stories

Can nanotechnology help treat Alzheimer's?

June 19, 2018
Alzheimer's disease (AD) is the most common form of dementia. It takes a devastating toll on patients and family members, who are usually the caregivers. Current drugs only treat symptoms of AD, not its causes.

Hyperactive neurons may be culprit in Alzheimer's

January 13, 2016
A long-term reduction in neuronal activity reduces amyloid plaques associated with Alzheimer's disease, Yale University researchers have found. The study, using mouse models of Alzheimer's, found the opposite is also true—triggering ...

Can aspirin treat Alzheimer's?

July 2, 2018
A regimen of low-dose aspirin potentially may reduce plaques in the brain, which will reduce Alzheimer's disease pathology and protect memory, according to neurological researchers at Rush University Medical Center, who published ...

Alzheimer's disease and type 2 diabetes—hope for inhibitors against amyloid plaques

August 8, 2018
Effective therapeutics to counteract the formation of amyloid plaques in Alzheimer's disease and type 2 diabetes are not yet available. Scientists at the Technical University of Munich (TUM) have now come a little bit closer ...

New tools could uncover important answers for Alzheimer's researchers

April 30, 2018
Alzheimer's disease currently affects more than 5.5 million Americans and is one of the costliest diseases to treat, according to the Alzheimer's Association. Characterized by a buildup of plaque in the brain, few animal ...

Detecting Alzheimer's disease before it's too late

April 23, 2018
The rate at which the protein beta-amyloid accumulates into the sticky plaques associated with Alzheimer's disease (AD) is already slowing by the time a patient would be considered to have preclinical AD, according to a longitudinal ...

Recommended for you

Does diabetes damage brain health?

December 14, 2018
(HealthDay)—Diabetes has been tied to a number of complications such as kidney disease, but new research has found that older people with type 2 diabetes can also have more difficulties with thinking and memory.

Amyloid pathology transmission in lab mice and historic medical treatments

December 13, 2018
A UCL-led study has confirmed that some vials of a hormone used in discontinued medical treatments contained seeds of a protein implicated in Alzheimer's disease, and are able to seed amyloid pathology in mice.

Study links slowed brainwaves to early signs of dementia

December 13, 2018
To turn back the clock on Alzheimer's disease, many researchers are seeking ways to effectively diagnose the neurodegenerative disorder earlier.

New discoveries predict ability to forecast dementia from single molecule

December 11, 2018
Scientists who recently identified the molecular start of Alzheimer's disease have used that finding to determine that it should be possible to forecast which type of dementia will develop over time—a form of personalized ...

Researchers classify Alzheimer's patients in six subgroups

December 5, 2018
Researchers studying Alzheimer's disease have created an approach to classify patients with Alzheimer's disease, a finding that may open the door for personalized treatments.

Neuroscientists pinpoint genes tied to dementia

December 3, 2018
A UCLA-led research team has identified genetic processes involved in the neurodegeneration that occurs in dementia—an important step on the path toward developing therapies that could slow or halt the course of the disease. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.