DNA methylation and the likelihood of death

Epigenetic clock predicts life expectancy

Julia Korowski, XX2 CENTURY, based on the materials of the University of California Los Angeles: Epigenetic clock predicts life expectancy, UCLA-led study shows

A team of scientists from 7 countries has demonstrated that DNA methylation can not only determine a person's biological age, but also predict his life expectancy. The results of the study are published in the journal Aging (Chen et al., DNA methylation-based measures of biological age: meta-analysis predicting time to death – VM).

The research team received 13 data sets collected during other studies, including the Framingham Heart Study and the Women's Health Initiative. Then 25 organizations examined DNA in blood samples of 13,000 people. Using molecular genetics techniques, including the "epigenetic clock" technique developed by Steve Horvath in 2013, scientists calculated the aging rate of each study participant.

 The "clock" estimates the age of body tissues based on methylation, a natural process of DNA modification. Comparing the actual age of people with the biological age of blood, the scientists calculated the life expectancy of the study participants. "We were amazed that the epigenetic clock could predict the life expectancy of white Europeans, Spaniards and African Americans," says Brian Chen, lead author of the study. "The data remained correct even when adjusted for traditional risk factors such as actual age, gender, smoking, body mass index, life history and blood test."

However, the results did not apply to everyone. "We found that 5% of the population at the biological level age faster, as a result, their life expectancy is shorter," explains Steve Horvath – Accelerated aging increases the risk of death by 50% – at any age." For example, take two sixty–year-old men - Peter and Joe. Both smoke to cope with stress, but Joe's epigenetic aging rate is average, and the unfortunate Peter falls into 5% of the "rapidly senile" population. The probability that Joe will die within the next 10 years is 60%, for Peter it is higher – 75%.

These preliminary results may explain why some die young – even though they eat healthy, drink moderately and do not smoke. "Although a healthy lifestyle can increase life expectancy, biological aging does not allow us to run from death forever," says Horvath. "However, risk factors such as smoking, diabetes and high blood pressure make it possible to predict mortality more accurately than the rate of epigenetic aging." "This study confirms that DNA methylation can serve as a biomarker of biological age," says one of the authors of the work, Dr. Douglas Kiel. "And if we can prove that DNA methylation accelerates aging, we can develop strategies to slow it down and maximize healthy years of life."

However, it is not yet known what role the epigenetic clock plays in the aging process. "Do epigenetic changes associated with actual age cause the death of elderly people? – says a member of the scientific group Themistocles Assimes (Themistocles Assimes). – They probably just contribute to the development of certain diseases or disrupt the ability to resist them. To answer these questions, it is necessary to continue research." In the future, scientists are going to look at well–documented causes of death - these studies will help them understand what the relationship between biological age and specific diseases is.

Methylation is a chemical modification catalyzed by an enzyme, the reaction of adding methyl groups (CH3) to specific sites (sites) of proteins, DNA and RNA.
The method of "epigenetic clocks", which allows to estimate the biological age of tissue, was developed by Steve Horvath, a specialist in mathematics and biological statistics. He used published data from genome methylation analysis and, using machine learning, trained an algorithm to calculate age. The algorithm identified methylation sites, which later formed the basis of the "epigenetic clock". Analysis of the methylation profile in these areas allows us to estimate the age of tissues with an error of no more than three years

Portal "Eternal youth" http://vechnayamolodost.ru  29.09.2016