A blood test that is able to determine "biological age" or how quick a person is aging has been developed. This is not only a tool for early detection of Alzheimer's disease and other kinds of dementia or brain disease but is also a predictor of "youthfulness" in organs for transplantation.
"We use birth year, or chronological age to judge everything from insurance premiums to whether you get a medical procedure or not. Most people accept that all 60-year-old are not the same, but there has been no reliable test for underlying biological age," said lead research Professor James Timmons from King's College London.
The team analyzed and compared the activity levels of panel key genes in men aged between 25 and 65 years old by determining the levels of RNA. Originally, there was about 500,000 gene activity evaluated but was marked down to 150, which served as indicators of good health and were utilized to come up with a score-based rating system.
The group then worked with 700 healthy 70-years-old Swedish men and studied their health records for the last two decades. They used the markers to compare the RNA level activity. They found that in over a 12-year period, higher scores are associated with better cognitive and kidney functions while lower scores are linked to Alzheimer's disease.
"Our discovery provides the first robust molecular 'signature' of biological age in humans and should be able to transform the way that 'age' is used to make medical decisions. This includes identifying those more likely to be at risk of Alzheimer's, as catching those at 'early' risk is key to evaluating potential treatments," Prof. Timmons stated.
The group of researchers found that for people suffering from Alzheimer's, the activity in the brain and blood was similar, thereby giving researchers an easy way to examine brain activity by just assessing blood samples.
"This is the first blood test of its kind and has shown that the same set of molecules is regulated in both the blood and the brain regions associated with dementia, and it can help contribute to a dementia diagnosis... It suggests we can use the gene-signature to better understand Alzheimer's disease and also as a screen for looking at drugs in human cells - an early step in drug discovery," Timmons added.
However, the test is not applicable to lifestyle-associated disorders like heart disease. But it would be more beneficial if people age 40 years and above take the test.
"One of the biggest questions in human biology is how we age, and how this process impacts our wider health and risk for conditions like Alzheimer's. This study suggests a way to measure a person's 'biological age' and could reveal insights into the ageing process and why some people are more susceptible to age-related health conditions," said Dr. Eric Karran, lead researcher at Alzheimer's research in U.K.
"People shouldn't take these findings to mean that most cases of Alzheimer's are inherited as this is not true. The markers identified in this study are affected by the complex interaction between genetic and environmental factors and we'll need further research to fully understand what they are telling us about the disease process," said research director of Alzheimer's Society, Dr. Doug Brown.
