Ovarian Somatic Cells: Cellular Heterogeneity and Functional Dynamics Across Health, Ageing, and Disease

The ovary is a highly dynamic organ in which the somatic cell population plays essential roles in coordinating folliculogenesis, steroidogenesis, and tissue homeostasis. Increasing evidence highlights substantial cellular heterogeneity and functional plasticity within the ovarian somatic compartment, which is dynamically modulated across the reproductive lifespan. The ovarian somatic cells exhibit distinct transcriptional profiles and functional states that evolve across developmental stages and throughout the reproductive cycle. During ageing, somatic cell composition and function are reshaped, promoting inflammatory responses, stromal remodelling, and reduced support for oocyte developmental competence. Dysregulation of their function and plasticity is also increasingly implicated in reproductive disorders (such as polycystic ovary syndrome, premature ovarian insufficiency and ovarian fibrosis). This review aims to consolidate emerging evidence of the central role of ovarian somatic cells and provides a unifying framework that integrates their roles in physiological ovarian function, ageing, and clinically relevant ovarian disorders.