Dementia test: ‘Velcro’ style test could spot Alzheimer’s years before symptoms develop

The dementia test uses magnets and detects rogue proteins called prions – and has been described as a potential “game changer”. The technique also picks up early stages of Parkinson’s and other neurodegenerative conditions such as Mad Cow’s disease or CJD (Creutzfeldt-Jakob disease). Early symptoms of Alzheimer’s disease include misplacing items, forgetting names of places and objects and having trouble thinking of the right word.

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As part of the test, tiny bead like magnets are injected into the body. They then stick to diseased molecules – leaving healthy ones alone.

Co author Dr Michael Connolly, a senior scientific engineer at the Berkeley Lab, California, said: “It’s like Velcro.”

It is hoped the little balls will one day be used to deliver medications that destroy clumps of neuron killing proteins in the brains of dementia patients.

One of the reasons drugs trials have failed is they are prescribed too late – once the devastating disorder has taken hold.

In tests it picked up prions from the blood of infected mice and hamsters in the pre clinical stages – as well as after they had developed symptoms.

It is a significant step closer to the first non invasive prion detection test in humans, say the US team.

The only current method is an unpleasant procedure known as a lumbar puncture. It involves sticking a needle into the back to extract fluid surrounding the spinal cord.

Prion diseases are a family of fatal brain illnesses caused by accumulations of misfolded copies of a naturally occurring protein.

But now there is finally an effective way to check for them – opening the door to a revolutionary screening tool.

The minute balls are made out of peptoids, artificial compounds designed to imitate proteins.

When they are added into a liquid, such as blood or cerebrospinal fluid found in the brain and spinal cord, they latch onto prions – avoiding normal proteins. This makes them easily identifiable.

Dr Connolly said: “The aggregated misfolded protein has multiple hooks – multiple binding sites – that will attach to the bead, which is like the complementing sheet. But the natural, correctly folded protein only has a single hook, so its binding affinity is much less.”

Prions are believed to be linked to Alzheimer’s disease. Recent research even suggests proteins called amyloid beta and tau, which clump together in the brains of patients, are actually prions.

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Lead author Professor Ronald Zuckermann, who has pioneered peptoids at the Berkeley Lab, explained: “Our peptoid beads have the ability to detect the misfolded proteins that act as infectious agents.

“So it could have a significant impact in the realm of prion diseases.

“But we have also shown they can seek out the large aggregated proteins that are the disease agents in Alzheimer’s and Parkinson’s diseases, among others.”

He added: “Prion diseases are rare, but there are many misfolded protein-based diseases, which affect millions of people, that are also very poorly understood.

“And like prion diseases, we need a way to diagnose these slow-onset conditions in the years before symptoms arise.”

There are currently no effective treatments for any prion diseases.

Dr Simone Hornemann, of University Hospital Zurich, said: “On top of potentially detecting asymptomatic disease carriers, the peptoid-bead MPA could be optimised to screen blood and blood products in a cheap and fast manner, a capability that will be very important for avoiding accidental transmission in case of a new prion disease outbreak.

“This assay could also be modified to test deer and elk for chronic wasting disease (CWD), a prion disease that is considered as a global epidemic in these animals.”

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