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Scientists have suggested that levels of the protein called clusterin rise 'many years' before symptoms of Alzheimer's disease first appear.
An early test for the condition could allow those patients could have early treatment and make improvements to their lifestyle to minimise the impact of the disease.
The study, conducted by the Institute of Psychiatry at King's College London, also found that very high levels of the protein may be linked with more rapid and severe memory loss.
Patient groups said the prospect of a blood test for Alzheimer's disease was the 'holy grail' for researchers in this area and the latest findings bring this a step closer.
Alzheimer's disease is the most common form of dementia in Britain and affects almost 500,000 people. This is expected to double by 2050 as the population ages.
The ethics of any blood test to identify those in the very early stages of Alzheimer's disease would need to be examined carefully as there is no cure for the condition.
The researchers compared blood samples taken from 300 people with either Alzheimer's disease, mild impairment or normal brain function.
The found that clusterin levels were linked with Alzheimer's symptoms and higher levels indicated more rapid and severe memory loss and brain shrinkage as shown on brain scans.
Experiments with mice showed that the protein is produced in increasing amounts with age and is also linked to the development of plaques in the brain which interfere with cell communications systems. The clusterin surrounded the plaques.
It is not known if the plaques are the cause of Alzheimer's disease or a sign of it but this research has shown that the body produces greater quantities of clusterin along with the plaques and it may be an attempt to protect the brain from the build up of the plaques.
Therefore high levels of clusterin, which can be detected in a blood sample, could be used as an early warning sign that the body is already fighting Alzheimer's disease.
The findings are published in the Archives of General Psychiatry.
Using 60 patients in America they also found that clusterin levels can be used to predict Alzheimer's onset up to 10 years before symptoms appear. Clusterin levels were measured and compared with brain scans taken from the same patients 10 years later.
This revealed that the patients with high clusterin had high levels of plaques in the brain ten years later and this is an indication of the condition.
The researchers have not yet established what level of clusterin is normal and at what exact level it would indicate Alzheimer's was developing and this is the subject of further investigations.
Source: Google News
Date: 12/07/2010
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