New test could pave way for early detection of Alzheimer’s, other dementias

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A multi-institute effort has resulted in development of a novel test which could allow for better management of age-related diseases and identification of people most at risk of Alzheimer’s, other dementias.

The study published in Genome Biology showcases the work carried out by researchers at King’s College London, Karolinska Institutet in Sweden and Duke University in the USA wherein researcher used RNA-profiling to measure and compare gene expression in thousands of human tissue samples. Scientists found that the ‘activation’ of as many as 150 genes in the blood, brain and muscle tissue were a hallmark of good health at 65 years of age.

Scientists were then able to create a reproducible formula for ‘healthy ageing’, and use this to tell how well a person is ageing when compared to others born the same year. Their findings suggested that there is an extensive range in ‘biological age’ scores of people born at the same time indicating that a person’s biological age is separate and distinct to his or her chronological age.

One of the important findings was that low score was correlated with cognitive decline, implying that the molecular test could translate into a simple blood test to predict those most at risk of Alzheimer’s disease or other dementias and suitable for taking part in prevention trials.

Researchers note that a person’s score was not correlated with common lifestyle-associated conditions, such as heart disease and diabetes, and is therefore likely to represent a unique rate of ageing largely independent of a person’s lifestyle choices.

The findings of the study provide the first practical and accurate test for the rate at which individual bodies are ageing. If this is the case, it could lead to numerous insights in research because ‘age’ is a critical factor in almost every area of medicine.

At the same time, the molecular test could enable more suitable donor matching for older organ transplants and could also provide a more efficient way of determining if an animal model of ageing is suitable to evaluate the effectiveness of anti-ageing treatments.

However, the study does not provide insight into how to improve a person’s score and thus alter their ‘biological age’. While a low score could be considered as ‘accelerated ageing’, an important aspect of the work suggests that ageing does not now need to be defined only by the appearance of disease.

Lead author of the study, Professor James Timmons at the Division of Genetics and Molecular Medicine at King’s College London, said: ‘Given the biological complexity of the ageing process, until now there has been no reliable way to measure how well a person is ageing compared with their peers. Physical capacity such as strength or onset of disease is often used to assess ‘healthy ageing’ in the elderly but in contrast, we can now measure ageing before symptoms of decline or illness occur.

“We now need to find out more about why these vast differences in ageing occur, with the hope that the test could be used to reduce the risk of developing diseases associated with age.”

Dr Neha Issar-Brown, programme manager for population health sciences at the MRC added: ‘Whilst it is natural for our bodies and brains to slow down as we age, premature ageing and the more severe loss of physical and cognitive function can have devastating consequences for the individual and their families, as well as impact more widely upon society and the economy.

“This new test holds great potential as with further research, it may help improve the development and evaluation of treatments that prolong good health in older age.”