Primates Study Unveils Development of Ovarian Reserve, Advancing Women's Health Research

Researchers at UCLA have created a comprehensive map detailing how the ovarian reserve forms in primates, offering valuable insights into female reproductive health. This achievement could revolutionize approaches to treating infertility and hormonal disorders such as polycystic ovary syndrome (PCOS). The study, published in Nature Communications, is the result of a six-year collaboration among scientists from UCLA, Harvard, UC San Francisco, and the Oregon National Primate Research Center. It focuses on the ovarian reserve—the finite number of eggs a woman is born with—which is crucial not only for reproduction but also for hormone production that governs menstrual cycles and menopause.

Understanding the development of this reserve has been challenging due to limited access to human fetal ovaries and the complexity of ovarian formation before birth. To bypass this obstacle, the team turned to rhesus macaques, primates that share approximately 93% of their DNA with humans and exhibit similar ovarian development patterns. Using advanced single-cell sequencing and spatial transcriptomics technologies, the scientists examined ovarian development from earliest stages, identifying key processes such as initial ovary formation, sex determination, and follicle creation—the protective sacs that support egg survival.

A significant breakthrough from this research is the cellular explanation for mini-puberty—a hormone surge in infants shortly after birth. The study found that hormone-producing cells activate in the ovary before birth, triggering this surge, which could serve as an early indicator of ovarian health. Absence of mini-puberty might signal potential issues like PCOS, affecting about 10% of women worldwide, paving the way for early diagnosis and intervention.

The detailed atlas produced by this research has immediate applications for stem cell scientists working to develop accurate ovarian organoids. Prior efforts were limited by a lack of detailed cellular information. Now, with this roadmap, scientists aim to generate essential ovarian support cells from stem cells and combine them with lab-grown germ cells to create sophisticated three-dimensional ovarian models. These models could deepen understanding of infertility causes and accelerate therapy development.

Overall, this study highlights the importance of basic research into the ovarian organ, which has largely been understudied, and demonstrates how detailed knowledge of ovarian development can lead to significant advancements in women's reproductive health.