DNA methylation as a window into female reproductive aging.

ABSTRACT

People with ovaries experience reproductive aging as their reproductive function and system declines. This has significant implications for both fertility and long-term health, with people experiencing an increased risk of cardiometabolic disorders after menopause. Reproductive aging can be assessed through markers of ovarian reserve, response to fertility treatment or molecular biomarkers, including DNA methylation. Changes in DNA methylation with age associate with poorer reproductive outcomes, and epigenome-wide studies can provide insight into genes and pathways involved. DNA methylation-based epigenetic clocks can quantify biological age in reproductive tissues and systemically. This review provides an overview of hallmarks and theories of aging in the context of the reproductive system, and then focuses on studies of DNA methylation in reproductive tissues.

People with ovaries experience a natural decline in the function of their reproductive system as they age. This decline eventually leads to menopause, and after menopause, people have an increased risk of developing cardiovascular or other chronic diseases. In the clinic, it is hard to measure aging of the reproductive system, so other markers of the ovary's function, like the number of remaining eggs, are used. We can also measure reproductive aging using molecular biomarkers, which can help us determine when a person's molecular age is different from their chronological age. This review focuses on an overview of biological processes and theories associated with aging, and then focuses on what can be learned from molecular biomarkers.