An international team of researchers, including scientists from Arizona State University's School of Life Sciences and Center for Evolution and Medicine, has discovered that different organs age in distinct ways at the molecular level. Their findings also challenge the long-held belief that early-life adversity simply accelerates aging. Instead, difficult experiences in early life may influence how aging develops differently across the body.

Published in the journal Science, the study examined DNA methylation—chemical markers that regulate gene activity without altering the DNA sequence—in multiple tissues of rhesus macaques. The research provides one of the most comprehensive maps to date of how aging affects the body's epigenome.

"We often talk about aging as though it is one single process," said Baptiste Sadoughi, postdoctoral researcher and co-first author of the study. "However, increasing evidence shows that different bodily functions decline at different rates and at different times."

Because the researchers had access to extensive life-history data for the monkeys, they were able to investigate how DNA methylation changed throughout life while considering early-life experiences. Sadoughi played a key role in analyzing large genomic datasets to create a detailed atlas of DNA methylation patterns across multiple tissues and to examine how these patterns evolved with age.

The researchers expected to observe similar molecular aging patterns throughout the body. Instead, they found that each organ followed its own aging trajectory.

"Aging is more like a mosaic," Sadoughi explained. "The regions that change are not the same across tissues."

For example, genomic regions that changed in the heart often differed from those changing in the liver or other organs. These findings suggest that the effects of early-life adversity on lifespan cannot be explained solely by accelerated aging.

Despite these differences, the organs still appeared to age in a coordinated manner overall. By developing biological aging "clocks" based on DNA methylation, researchers found that individuals who appeared biologically older in one organ generally appeared older in others as well, even though the underlying molecular changes varied between tissues.

The study also provides new insights into how early-life adversity affects long-term health.

Previous studies have linked childhood adversity with increased risks of disease and earlier mortality, leading researchers to believe that difficult early experiences accelerate biological aging. To test this theory, the team examined several forms of adversity experienced by the macaques, including maternal loss and challenging social environments.

The findings were more complex than anticipated. Rather than uniformly making tissues appear biologically older, early-life adversity produced varying effects across the body. Some tissues appeared biologically younger, one appeared older, and most showed no significant change in biological age.

"Early-life adversity and aging are related, but they are not the same process," said Rachel Petersen, a postdoctoral researcher at Vanderbilt University and co-lead author of the study.

These results indicate that aging is only one of several biological pathways through which early experiences affect health later in life. Other mechanisms, many of which remain unknown, are likely involved as well.

Although the study improves understanding of how early experiences become biologically embedded, the researchers emphasize that early adversity does not determine a person's future health outcomes. Factors later in life, including social support and access to resources, can significantly influence long-term wellbeing.

"We know people are not destined for poor outcomes," Sadoughi said. "With support and recognition of increased risk, there is strong evidence that the effects of early traumatic experiences can be reduced."

Beyond advancing knowledge of aging biology, the research may also contribute to the development of new health biomarkers. Scientists hope that, in the future, DNA methylation patterns measured from a simple blood sample could provide insights into the health of organs that are otherwise difficult to assess directly.

Source: https://news.asu.edu/b/20260709-early-life-adversity-doesnt-simply-speed-aging-it-changes-how-body-ages