The rate of aging
A group of researchers led by Daniel Belsky from the Mailman School of Public Health at Columbia University reported measuring DNA methylation in blood cells, which is sensitive to changes in the rate of biological aging among people of the same chronological age – participants in the Dunedin Longitudinal Study.
A tool called DunedinPoAm (Dunedin(P)ace (o)f(A)ging in (m)ethylation) is unique among interventional tests for natural experimental studies on the rate of aging, its change through behavioral or drug therapy or under the influence of the environment.
The aim of the study was to measure the rate of biological aging based on 12-year observation of 18 different clinical indicators in a blood test that can be determined simultaneously.
Middle-aged adults who had previously shown aging according to the results of the new tool showed a faster decline in physical and cognitive functions, they looked older in photographs. Older people who age faster, according to the results of DunedinPoAm, have an increased risk of developing chronic diseases and mortality. In other analyses, the researchers showed that DunedinPoAm collected new information not measured by available estimates of biological aging, for example, that people who had experienced poverty or violence in childhood showed faster aging. However, DunedinPoAm's predictions could have been altered by lifestyle intervention.
In a 2015 paper, Belsky and his colleagues at Duke University, who collaborated on the new study as well, tracked clinical tests performed on 954 Dunedin study cohort volunteers aged 26, 32 and 38 to measure their aging rate. The striking finding of this earlier study was that the rate of biological aging varied greatly even at a young age when there were no chronic diseases. But a test called "Aging Rate," developed by researchers in this earlier study, required a long follow-up time and careful clinical evaluation.
In the new study, the authors sought to develop a blood test that could be performed at the beginning and end of a randomized controlled trial to determine whether treatment slowed the participants' aging rate. Slowing down the rate of aging is a new goal of medical research as a new approach to the prevention of chronic diseases.
The author's analysis of DunedinPoAm is performed on DNA samples obtained from leukocytes. The team analyzed chemical markers on DNA called methylating tags. DNA methylation is an epigenetic process that can change the way genes are expressed. DNA methylation labels change with age: some are added, others are lost.
The work included data analysis from Dunedin studies in New Zealand, Understanding Society and E-Risk in the UK, Normative Aging in the USA and a randomized clinical trial of CALERIE.
Previous studies have assessed the rate of aging by analyzing differences in DNA methylation between people of different ages. One of the limitations of this approach is that people born in different years grew up in different historical conditions, with the possibility of greater exposure to diseases in children, tobacco smoke, lead in the air and less exposure to antibiotics and other drugs, as well as nutrition that affect DNA methylation. An alternative approach is to study people who were born in the same year and find methylation models that differentiate those who aged biologically faster or slower compared to their peers.
The authors used a machine learning technique (elastic network regression) to analyze data on more than 400,000 different DNA methylation labels and find those associated with physiological changes recorded when measuring the rate of aging. As a result, the analysis revealed a set of 46 methylating labels that together measured the rate of aging. 46 points are combined in the DunedinPoAm algorithm, the average person has a value of 1 – this is the correspondence of one year of biological aging to one chronological year. Among the Dunedin study participants, the range of values ranged from 0.6 (that is, the aging rate is almost 40% slower than normal) to almost 1.4 (that is, the aging rate is 40% faster than normal).
Article by D.W.W.Belsky et al. Quantification of the pace of biological aging in humans through a blood test, The DunedinPoAm DNA methylation algorithm is published in the journal e-Life.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru Based on Columbia University Mailman School of Public Health: New Tool Measures the Pace of Aging Across the Life Course.