Eliminating dead-but-toxic cells occurring naturally in the brains of mice designed to mimic Alzheimer’s slowed neuron damage and memory loss associated with the disease, according to a study published Wednesday that could open a new front in the fight against dementia.The accumulation in the body of “zombie cells” that can no longer divide but still cause harm to other healthy cells, a process called senescence, is common to all mammals.
Scientists have long known that these dead-beat cells gather in regions of the brain linked to old age diseases ranging from osteoarthritis and atherosclerosis to Parkinson’s and dementia.
Prior research had also shown that the elimination of senescent cells in ageing mice extended their healthy lifespan.
But the new results, published in Nature, are the first to demonstrate a cause-and-effect link with a specific disease, Alzheimer’s, the scientists said.
But any treatments that might emerge from the research are many years down the road, they cautioned.
In experiments, a team led by Tyler Bussian of the Mayo Clinic in Rochester, Minnesota used mice genetically modified to produce the destructive, cobweb-like tangles of tau protein that form in the neurons of Alzheimer’s patients.
The mice were also programmed to allow for the elimination of “zombie” cells in the same region.
“When senescent cells were removed, we found that the diseased animals retained the ability to form memories, and eliminated signs of inflammation,” said senior author Darren Baker, also from the Mayo Clinic.
The mice likewise failed to develop Alzheimer’s signature protein “tangles”, and retained normal brain mass.
Keeping zombies at bay
A closer look revealed that the “zombies” belonged to a class of cells in the brain and spinal cord, called glia, that provide crucial support and insulation to neurons.
“Preventing the build-up of senescent glia can block the cognitive decline and neuro-degeneration normally experienced by these mice,” Jay Penney and Li-Huei Tsai, both from MIT, wrote in a comment, also in Nature.
Bussian and his team duplicated the results with pharmaceuticals, suggesting that drugs could one day slow or block the emergence of Alzheimer’s by keeping these zombie cells at bay.
“There hasn’t been a new dementia drug in 15 years, so it’s exciting to see the results of this promising study in mice,” said James Pickett, head of research at Alzheimer’s Society in London.
For Lawrence Rajendran, deputy director of the Dementia Research Institute at King’s College London, the findings “open up new vistas for both diagnosis and therapy for neurodegenerative diseases, including Alzheimer’s.”
Up to now, dementia research has been mostly focused on the diseased neurons rather than their neighboring cells.
“It is increasingly becoming clear that other brains cells play a defining role,” Rajendran added.
Several barriers remain before the breakthrough can be translated into a “safe, effective treatment in people,” Pickett and other said.
The elderly often have lots of harmless brain cells that look like the dangerous senescent cells a drug would target, so the molecule would have to be good at telling the two apart.
The team studied gaming data taken from 27,108 UK players, aged 50-75 years and the most vulnerable age-group to develop Alzheimer’s in the next decade. They compared this benchmark data with a smaller lab-based group of 60 people who underwent genetic testing
A specially designed smartphone game can detect people at the risk of developing Alzheimer’s, say researchers.
The game called Sea Hero Quest, downloaded and played by over 4.3 million people worldwide, helped researchers from the University of East Anglia (UEA) better understand dementia by seeing how the brain works in relation to spatial navigation.
The game has been developed by Deutsche Telekom in partnership with Alzheimer’s Research UK, University College London (UCL) and the University of East Anglia.
“Dementia will affect 135 million people worldwide by 2050. We need to identify people to reduce their risk of developing dementia,” said Lead researcher Professor Michael Hornberger from UEA’s Norwich Medical School.
As players made their way through mazes of islands and icebergs, the research team translated every 0.5 seconds of gameplay into scientific data. The team studied how people who are genetically pre-disposed to Alzheimer’s play the game compared with those who are not.
The results, published in the journal PNAS, showed people genetically at risk of developing Alzheimer’s can be distinguished from those who are not on specific levels of the Sea Hero Quest game.
The findings are particularly important because a standard memory and thinking test cannot distinguish between the risk and non-risk groups. “Our findings show we can reliably detect such subtle navigation changes in at-genetic-risk of Alzheimer’s compared with healthy people without any symptoms or complaints,” said Hornberger.
The team studied gaming data taken from 27,108 UK players, aged 50-75 years and the most vulnerable age-group to develop Alzheimer’s in the next decade. They compared this benchmark data with a smaller lab-based group of 60 people who underwent genetic testing. (IANS)