Report by Shuchi Giridhar
A group of neuroscientists from the University of Pittsburgh, in Pennsylvania (USA), have created a new biomarker (a test that looks for genes, proteins, and other substances called ‘biomarkers’) blood test to find out whether a person has Alzheimer’s disease.
The new test is called “brain-derived tau,” or BD-tau. A study based on the results has been published in the journal ‘Brain’.
What is Alzheimer’s disease?
Alzheimer’s disease is a progressive (something that grows with time) neurological disorder that affects the brain. It causes the death of brain cells which in turn causes the brain to shrink. Senior citizens are more prone to this disorder.
It causes decline in thinking, behaviour, and social skills.
Over a period of time, the patient is not able to function independently. They tend to forget the way to their home, or how to drive, or where they have placed items of everyday use.
Around 24 million people worldwide have the disease.
If a person forgets recent events frequently, they may have the disease.
As the disease progresses, it causes severe memory loss and the patient will no longer be able to perform daily tasks efficiently.
Alzheimer’s can be treated but the medication only extends the period of time.
How does this blood test determine if one has Alzheimer’s?
There are three distinct markers that can help detect whether one has the disease.
The first one is a high accumulation of tau and amyloid protein.
The second one is the loss of neuronal cells in specific parts of the brain. This loss is slow and progressive and is known as neurodegenaration.
Detecting high traces of tau and amyloid in the blood can be done without much difficulty, but detecting nerve cell damage, that too in specific parts of the brain, is not as easy.
Prof. Thomas Karikari from the University of Pittsburgh, along with his colleagues from around the world, has focused on and developed an antibody blood test that would detect brain – derived tau, a form of tau protein specific to Alzheimer’s. 600 patients at different stages of the disease were tested on and found that the blood test could differentiate Alzheimer’s with other diseases relatively well.
Why is this blood test more effective than other methods?
A few of the other methods to detect if one has Alzheimer’s are neuro imaging and lumbar puncture. But neuro imaging is very expensive, difficult to schedule, and requires MRI and PET scanners. Not many people in the US have access to MRI and PET scanners, so that is a major issue.
On the other hand, a lumbar puncture is very painful. And very often people experience headache and back pain after the procedure.
A blood test is cheaper and much easier to perform. Blood tests are also safer in comparison with the other methods.
What is the next step?
The blood test must be tried on a wide range of patients – such as people from different racial and ethnic backgrounds. It must also be tested on people going through different stages and symptoms of memory loss or dementia.
Professor Karikari hopes that monitoring levels of brain derived tau protein might help in clinical treatment for Alzheimer’s.