Certain chemicals, diet, accelerate epigenomic aging

Exposure to endocrine-disrupting chemicals (EDCs) while the liver is developing prematurely aged the liver epigenome, according to a new study published in the journal Nature.

The epigenome, sometimes referred to as the operating system of the genome, comprises small chemical modifications to DNA and the proteins that make up our chromosomes and controls the activity of all the genes within the genome, the researchers said.

During early life, as our organs develop, the epigenome guides and changes along with normal developmental milestones. Exposure to EDCs during this process can cause widespread reprogramming of the epigenome, and this reprogramming persists for the life of the individual. Depending on the organ, the window of vulnerability for this reprogramming may be anytime from development in the womb to childhood and adolescence, depending on how long normal development lasts, the researchers said.

In a healthy liver, the epigenome goes through a normal aging process. In this study, after exposure to an EDC, the researchers saw that this process accelerated. For example, a six-day-old rat had the same epigenome they would normally see in an adult rat.

Rats that were exposed early to EDC and later to a Western-style diet were found to be more susceptible to metabolic dysfunction than those that had the same EDC exposure but were kept on a healthy diet. Those that remained on a healthy diet, despite the fact their epigenome had been reprogrammed, did not show the same changes in expression of genes that control metabolism, or accumulation of lipids in their serum, seen in rats on the high fat, sugar, and cholesterol diet.

“This study shows us how environmental exposures affect our health and disease susceptibility, both early and later in life," said Cheryl Walker, PhD, lead author of the study and professor and director of the Center for Precision Environmental Health at the Baylor College of Medicine, in a statement. "It also shows us that some people may be more adversely affected by a high-fat diet as adults than others due to environmental exposures they experienced earlier in their life."