Scientists are getting closer to understanding how ovaries develop egg cells, or ovarian reserve. A recent study published in Nature Communications explored this process in monkeys, which share many physiological traits with humans. Researchers examined tissue samples from various developmental stages, providing valuable insights into how ovarian reserve forms from the early stages of embryo development to six months after birth.
Amander Clark, a developmental biologist at UCLA and a co-author of the study, noted that this research fills important gaps in our understanding of ovarian biology. The newly created map of ovarian development can help researchers better study reproductive diseases like polycystic ovary syndrome (PCOS), a condition linked to hormonal imbalance and infertility.
Ovaries play two crucial roles in women’s health: producing eggs and releasing hormones such as estrogen and progesterone. Ovaries start forming around six weeks after fertilization. Early on, germ cells divide and connect in clusters called nests. When these nests break apart, individual egg cells emerge, surrounded by pregranulosa cells that support their growth.
By around 20 weeks after fertilization, primordial follicles—encased eggs—begin to develop. These follicles are essential as they ensure the ovaries can produce eggs and hormones. However, various ovarian conditions stem from issues with these cells. For instance, while the exact cause of PCOS is still unclear, it is known to involve problems in primordial follicles.
In their study, Clark and her team discovered that pregranulosa cells form in two waves, with the significant action happening in the second wave. They identified specific genes that may help clarify the origins of issues related to ovarian reserve. Interestingly, they found signs that the ovaries might undergo what Clark calls “practice rounds” of follicle development before birth, hinting at a more complex process than previously understood.
Despite these breakthroughs, Luz Garcia-Alonso, a computational biologist not involved in the study, cautioned that this is a dynamic development phase. Cell compositions can change rapidly, calling for more detailed studies to get a clearer picture of ovarian development.
This growing body of research opens new avenues for understanding fertility issues and could potentially lead to breakthroughs in treatment for reproductive disorders. For more information, you can check out trusted sources like the National Institutes of Health and World Health Organization.
