Lack of cleaning in brain cells causes Alzheimer's: Study

A weakened cleaning system of the brain cells in animals and humans is central to developing Alzheimer's disease, according to a study which may lead to new treatments for the neurodegenerative disorder.

Researchers, including those from the University of Copenhagen in Denmark, found that improving mitophagy -- the cleaning system of the brain cells -- nearly removed the symptoms of Alzheimer's in the animals.

Scientists around the world are still struggling to understand Alzheimer's better in order to treat and potentially prevent the development of the debilitating disease in the future. No new medications have been approved in recent years.

The study, published in the journal Nature Neuroscience, may lead to new treatments for the disease by targeting the mitophagy process.

"When the cleaning system does not work properly, there will be an accumulation of defective mitochondria in the brain cells. And this may be really dangerous," said Vilhelm Bohr from the National Institutes of Health in the US.

"At any rate, the cleaning system is markedly weakened in cells from both humans and animals with Alzheimer's. And when we improve the cleaning in live animals, their Alzheimer's symptoms almost disappear," Bohr said.

The researchers looked more closely at the cleaning process in brain cells from deceased Alzheimer's patients, in Alzheimer's-induced stem cells, and in live mice and roundworms with Alzheimer's.

In addition, they also tested active substances targeted at the cleaning process in the animal models.

"It significantly strengthens our results that the cleaning process seems to be important in both human cells and across animal species. It is encouraging that in living animals, we are able to improve the central Alzheimer's symptoms involving memory and learning," said Bohr.

Mitochondria live inside cells and can be seen as the cell's energy factories. Mitophagy breaks down defective mitochondria and reuses their proteins.

It is known from previous research that dysfunctional mitophagy is associated with poor function and survival of nerve cells, but so far, no connection with Alzheimer's has been shown.

In both Alzheimer's and other states of dementia, there is an accumulation of the proteins tau and beta amyloid in the brain, leading to cell death.

In the new animal models, the researchers show that when boosting mitophagy, this accumulation will slow down.

The researchers believe that their findings indicate that the cleaning process is a potential target for the treatment of Alzheimer's, which should be further investigated.

They plan to start clinical trials in humans in the near future.