Despite the importance of neuropilins (NRPs) in a number of processes that are altered in endometriosis, such as angiogenesis and neuronal guidance, these molecules have not been previously studied in the disease. Similarly, potent lymphangiogenic factors, vascular endothelial growth factor C (VEGF-C) and VEGF-D, have not been comprehensively investigated in endometriosis. The objective of this study was to examine their expression in women with and without endometriosis. NRPs and VEGFs were quantified in 79 histologically normal uterine tissue samples (37 control and 42 endometriosis, all menstrual cycle phases) using immunohistochemistry and automated cellular imaging analysis. NRP-1 was significantly reduced in women with endometriosis (P = .004). The normal significant menstrual cyclical variations in endometrial NRP-1, NRP-2, and VEGF-C were absent in endometriosis, and VEGF-D was dysregulated. Dysregulated expression of growth factors and receptors, such as NRPs and VEGFs, likely contribute to altered angiogenesis, lymphangiogenesis, neurogenesis and immune function in endometriosis and may reflect altered hormone signals.
Keywords: endometriosis; eutopic endometrium; menstrual cycle; neuropilin; vascular endothelial growth factor.