07 September 2015

Molecular test for determining biological age and detecting Alzheimer's disease

An international group of researchers from the UK, Sweden, Denmark and the USA, working under the leadership of Professor James Timmons from King's College London, have developed a panel of molecular biomarkers that allows us to determine the "quality" of human aging, or its biological age. The low number of points scored by a person when tested using this panel also correlates with the decline of cognitive function, and scientists hope that it can be used to detect diseases such as Alzheimer's disease.

The authors used RNA molecules involved in the mechanism of protein synthesis as panel markers. The quantitative ratio of RNA molecules in a cell is a reflection of the activity of genes and is determined not only by the genetic profile of a person, but also by his lifestyle and environmental influences that ensure the activation or inactivation of certain genes. The study of the RNA profile provides specialists not only with information about the genes inherited by humans, but also the nature of the influence of external factors on their expression.

First, the authors used special chips to analyze the RNA content in the muscle tissue cells of 15 young people aged 19-28 years and 15 healthy elderly people aged 59-77 years. This allowed them to evaluate the expression of various genes and identify 150 genes whose activity levels differed significantly in the two age groups. After that, they repeated the experiment on other sets of muscle tissue samples.

The resulting genetic profile consisting of 150 genes was used to analyze 108 samples of muscle tissue of 70-year-old men. The results showed that the values of the "healthy aging indicator" vary significantly. That is, people with the same chronological age may differ in biological age, at least based on the profile of genetic expression. At the same time, the indicator proposed by the author was not associated with markers of other health indicators, such as blood pressure or cholesterol levels in the blood.

After that, the authors applied their panel to brain tissue samples and found that it allows differentiating samples of young and old people. Moreover, when analyzing the RNA profile of blood and brain cells, higher values of the healthy aging index were characteristic of elderly people with good health, while low levels were characteristic of people with early manifestations of cognitive decline and Alzheimer's disease.

Experts note that the test developed by the authors must be repeated and validated on larger groups of people. Only then can it be recognized as a useful clinical test for detecting Alzheimer's disease.

Article by Sanjana Sood et al. A novel multi-tissue RNA diagnostic of healthy aging relates to cognitive health status is published in the journal Genome Biology.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on Alzheimer's Research UK:
New molecular test reveals biological age and could help detect Alzheimer’s

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