A recent study published in Nature Communications by researchers at Karolinska Institutet offers new insights into the development of ovarian follicles, which are vital for female fertility as they contain oocytes. The study, led by Pauliina Damdimopoulou, Senior Lecturer and Research Group Leader at the Department of Clinical Science, Intervention and Technology, provides a detailed comparison of immature follicles from both children and adults. The findings reveal significant previously unknown variations in immature oocytes and identify key markers involved in the early growth activation of follicles.
Ovarian follicles are essential for female fertility , forming during fetal development and establishing a finite reserve of approximately one million primordial follicles. Each follicle contains one immature oocyte that is arrested in development and stays dormant until it is activated to grow. The activation and growth of follicles to ovulation is a process that spans about a year in humans.
While full growth to ovulation is only possible after puberty, the early stages of growth occur even in children. This study focuses on the early arrested follicles and their first stages of growth, providing the first ever comparison between adult and child follicles. The research team analyzed the transcriptomes of 120 immature follicles from both children and adults.
They discovered two main types of follicles in both age groups: one with a gene expression profile typical of immature.