Macrophage contributions to ovarian function

Macrophages are multifunctional cells that play key roles in the immune response and are abundant throughout female reproductive tissues. Macrophages are identified in tissues by their expression of cell surface receptors and can execute diverse functional activities, including phagocytosis and degradation of foreign antigens, matrix dissolution and tissue remodelling, and production and secretion of cytokines, chemokines and growth factors. Their specific localization and variations in distribution in the ovary during different stages of the cycle, as well as their presence in peri-ovulatory human follicular fluid, suggest that macrophages play diverse roles in intra-ovarian events including folliculogenesis, tissue restructuring at ovulation and corpus luteum formation and regression. This review presents the existing evidence for the regulation of ovarian function by macrophages and macrophage-derived products, highlighting the implications of these cells in ovarian diseases, particularly polycystic ovary syndrome, endometriosis and premature ovarian failure.