Authors: Alice Weatherston
Until now, there has been no reliable test for evaluating the biological age of individuals, especially those over 60 who are at increased risk of neurodegenerative diseases. A new study from King’s College London (UK) however, has highlighted a particular gene signature that may help in predicting the onset of diseases such as Alzheimer’s. The findings were published in Genome Biology recently.
The research team set out to define a set of genes that are associated with ‘healthy aging’ in a group of healthy 65 year old individuals. Each subject’s RNA was analyzed and the information collated was used to create a 150 RNA gene signature that represented ‘healthy aging’. The team demonstrated that the developed gene signature was a reliable predictor of age-related disease when RNA from a range of tissues, including human muscle, brain and skin was evaluated.
Following this, a ‘healthy age gene score’ was developed, enabling the team to directly compare the RNA profiles of different individuals. The scores also indicated that a higher ‘gene score’ was linked to better health in both male and female subjects.
RNA from healthy 70 year old individuals was also collected as well as follow-up data on the state of their health over two decades. At the age of 70 healthy age gene scores varied by a four-fold range between individuals, despite all being born within one year of each other. The variation was also shown to be associated with long-term health, with those exhibiting a greater gene score at the age of 70 showing better cognitive health and renal function, both of which are highly linked to mortality, up to 12 years later.
More specifically, patients diagnosed with Alzheimer’s exhibited a lower healthy age gene score, indicating the presence of a significant link between the score and the onset of the disease.
Lead author, James Timmons (King’s College London) commented: “This is the first blood test of its kind that has shown that the same set of molecules are regulated in both the blood and the brain regions associated with dementia, and it can help contribute to a dementia diagnosis. This also provides strong evidence that dementia in humans could be called a type of ‘accelerated aging’ or ‘failure to activate the healthy aging program’.”
Given the importance of early intervention in Alzheimer’s and identifying individuals most at risk of developing the disease, the novel health scoring system may help in recognizing which middle-aged subjects should be offered entry into preventative clinical trials, many years prior to any clinical signs of Alzheimer’s.
“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,” concluded Timmons.
Source: BioMed Central press release http://www.biomedcentral.com/presscenter/pressreleases/20150907