Post by Willow on Sept 7, 2015 12:52:45 GMT 9.5
A groundbreaking blood test that determines a person’s “biological age” will help to predict and diagnose dementia, scientists say.
The gene analysis technique, developed by researchers in Britain, Sweden and the United States, is the first to give an accurate impression of how healthily people are ageing. It would allow doctors to estimate their risk of a wide range of chronic illnesses and speed up the development of new drugs for Alzheimer’s disease.
It could also help doctors to make a decision on whether to screen their patients earlier or later for cancer, based on as little as a finger prick, researchers said.
The new technique is more specific and practical than current “biomarker” tests, which look for telltale compounds linked to a handful of related diseases, and appears to be much better at assessing risk levels among healthy people. The test screens patients’ RNA — genetic messenger molecules which cannot be “fooled” by conditions such as diabetes and high blood pressure.
Experts said that it could answer an urgent need for a cheap and easy means of selecting volunteers for dementia drug trials and help doctors to decide whether to send patients for brain scans and more expensive diagnostics.
James Timmons, professor of precision medicine at King’s College London and one of the senior authors of the study, said that it could explain why healthy people with similar lifestyles went on to develop different diseases at different ages.
“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,” he said. “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.”
Comparing skin, brain and muscle samples from 15 fit and healthy 25-year-olds and a further 15 healthy 65-year-olds, the scientists identified 150 strands of RNA linked to healthy ageing. They then tested their “healthy ageing gene score” on 108 men around the age of 70 from Uppsala in Sweden. Although they were all roughly the same age, their biological ageing scores were much more scattered, with some roughly 15 years older or younger than their chronological age.
The differences were played out in later life: by the age of 82, the men who had been judged to have better healthy ageing scores at 70 had significantly better kidney function and scored higher in cognitive tests. They were also much more likely to survive past their 90th birthday.
Further tests suggested that the technique was as good as the “best in class” for Alzheimer’s blood tests, but much faster and more practical. Biological ages might be a better basis for calculating when to send patients for check-ups than chronological age, the authors wrote in the journal Genome Biology.
Independent scientists said the blood test appeared promising but that the findings would need to be repeated before it could be safely introduced.
“It is worth noting that it is not yet a foolproof blood test for dementia,” Tara Spires-Jones, reader in cognitive and neural systems at the University of Edinburgh, said. “While an improvement over many studies, it appears from the data that people with dementia would not always be different from controls on this test.”
Doug Brown, director of research at the Alzheimer’s Society, said that there was an urgent need for people at high risk of dementia to take part in clinical trials of new treatments and that the new test could be a great help in identifying them, potentially speeding up the advent of new drugs.
Dr Brown emphasised that the tests did not mean high dementia risk was hereditary. “People shouldn’t take these findings to mean that most cases of Alzheimer’s are inherited, as this is not true,” he said.
“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.”
The Times
The gene analysis technique, developed by researchers in Britain, Sweden and the United States, is the first to give an accurate impression of how healthily people are ageing. It would allow doctors to estimate their risk of a wide range of chronic illnesses and speed up the development of new drugs for Alzheimer’s disease.
It could also help doctors to make a decision on whether to screen their patients earlier or later for cancer, based on as little as a finger prick, researchers said.
The new technique is more specific and practical than current “biomarker” tests, which look for telltale compounds linked to a handful of related diseases, and appears to be much better at assessing risk levels among healthy people. The test screens patients’ RNA — genetic messenger molecules which cannot be “fooled” by conditions such as diabetes and high blood pressure.
Experts said that it could answer an urgent need for a cheap and easy means of selecting volunteers for dementia drug trials and help doctors to decide whether to send patients for brain scans and more expensive diagnostics.
James Timmons, professor of precision medicine at King’s College London and one of the senior authors of the study, said that it could explain why healthy people with similar lifestyles went on to develop different diseases at different ages.
“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,” he said. “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.”
Comparing skin, brain and muscle samples from 15 fit and healthy 25-year-olds and a further 15 healthy 65-year-olds, the scientists identified 150 strands of RNA linked to healthy ageing. They then tested their “healthy ageing gene score” on 108 men around the age of 70 from Uppsala in Sweden. Although they were all roughly the same age, their biological ageing scores were much more scattered, with some roughly 15 years older or younger than their chronological age.
The differences were played out in later life: by the age of 82, the men who had been judged to have better healthy ageing scores at 70 had significantly better kidney function and scored higher in cognitive tests. They were also much more likely to survive past their 90th birthday.
Further tests suggested that the technique was as good as the “best in class” for Alzheimer’s blood tests, but much faster and more practical. Biological ages might be a better basis for calculating when to send patients for check-ups than chronological age, the authors wrote in the journal Genome Biology.
Independent scientists said the blood test appeared promising but that the findings would need to be repeated before it could be safely introduced.
“It is worth noting that it is not yet a foolproof blood test for dementia,” Tara Spires-Jones, reader in cognitive and neural systems at the University of Edinburgh, said. “While an improvement over many studies, it appears from the data that people with dementia would not always be different from controls on this test.”
Doug Brown, director of research at the Alzheimer’s Society, said that there was an urgent need for people at high risk of dementia to take part in clinical trials of new treatments and that the new test could be a great help in identifying them, potentially speeding up the advent of new drugs.
Dr Brown emphasised that the tests did not mean high dementia risk was hereditary. “People shouldn’t take these findings to mean that most cases of Alzheimer’s are inherited, as this is not true,” he said.
“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.”
The Times