First report of telocytes in human ovarian stroma: an ultrastructural and immunohistochemical study

Telocytes (TCs) are interstitial cells characterized by long, thin cytoplasmic extensions called telopodes. Although their presence has been established in various organs, data on their existence and organization within the human ovary remain limited. This study aimed to identify and describe telocytes in the ovarian stroma using immunohistochemical, immunofluorescence, and ultrastructural methods. Ovarian tissues from women aged 24-65 years who underwent total hysterectomy and bilateral salpingo-oophorectomy for nonmalignant uterine diseases were analyzed. TCs were identified by CD34 co-expression with c-KIT, vimentin, platelet-derived growth factor receptor (PDGFR)-β, and alpha-smooth muscle actin (α-SMA) and confirmed by transmission electron microscopy with immunogold labeling. The results demonstrated that telocytes form two to three discontinuous layers around the adventitia of large and medium-sized blood vessels and establish close contacts with stromal components, including smooth muscle cells. This spatial organization suggests their involvement in intercellular communication and stromal coordination within the ovarian microenvironment. These findings provide the first ultrastructural and immunohistochemical evidence of telocytes in the human ovarian stroma and highlight the need for further studies to clarify their physiological and pathological roles in ovarian function, including potential morphological and molecular differences among females of different age groups.