Aging clocks can accurately determine a person’s biological age; this age may differ from the person’s chronological age (age calculated from date of birth) due to environmental influences such as diet or smoking. The accuracy of these clocks indicates that the aging process follows a specific schedule.
Scientists David Meyer and Professor Dr. from CECAD, a cluster of enhanced cellular stress responses in aging-related diseases, at the University of Cologne. Björn Schumacher has now discovered that the aging clock actually measures the increase in stochastic changes in cells. The study was recently published Aging of Nature.
“Aging begins when the building blocks in our cells are damaged. Where this damage occurs is mostly coincidental. Our work combines the precision of aging clocks with the accumulation of completely stochastic changes in our cells,” said Professor Schumacher.
Less control, more noise
As we age, control of the processes occurring in our cells becomes less effective, leading to more stochastic outcomes. This is particularly evident in the accumulation of stochastic changes in DNA methylation. Methylation belongs to chemical changes that affect DNA, the building blocks of the genome. These methylation processes are tightly regulated in the body. However, random changes in methylation patterns occur throughout a person’s life. The accumulation of variations is a highly accurate indicator of a person’s age.
Loss of cellular control and increased stochastic variation is not limited to DNA methylation. Mayer and Schumacher show that increased stochastic variation in gene activity can also be used as an aging clock. “In principle, it might be possible to go even further by allowing stochastic variations in any process in the cell to predict age,” Schumacher said. According to the authors, it is important to first understand whether such aging times indicate the success of interventions that slow down the aging process or harmful factors that accelerate aging.
Using existing data sets, scientists showed that smoking exacerbates random changes in the human body, and that “anti-aging” measures such as reducing calorie intake in mice reduced variation in methylation patterns. They also showed that stochastic noise could even be reversed by reprogramming body cells into stem cells. Scientists compared human fibroblasts taken from the skin, reprogrammed into stem cells, and rejuvenated as a result of the reprogramming. The high variation indicating the age of the organism’s cells was actually the opposite of the low stochastic noise of young stem cells.
Meyer and Schumacher hope that their findings about loss of regulation and accumulation of stochastic variation will lead to new interventions that could address the root cause of aging and even lead to cellular rejuvenation. Such interventions may aim to restore stochastic changes in DNA or improve the control of gene expression.
Source: Port Altele
