Abstract

STUDY QUESTION: Do alterations in pro- and anti-angiogenic estrogen metabolites in follicular fluid (FF) contribute to the follicular growth arrest and anovulation associated with polycystic ovary syndrome (PCOS)? SUMMARY ANSWER: FF of PCOS women with anovulation have reduced levels of pro-angiogenic estrogen metabolites (EMs) and vascular endothelial growth factor (VEGF) compared to that of fertile women with regular menstrual cycles, but exogenous gonadotropins increase the pro-angiogenic EMs and VEGF levels in PCOS women. WHAT IS KNOWN ALREADY: PCOS is characterized by the arrest of follicular development that leads to chronic anovulation. Follicular arrest is generally associated with elevated plasma levels of luteinizing hormone (LH), androgens and anti-Mullerian hormone (AMH). There is also reduced angiogenesis in the follicles of PCOS women compared to those of normal cycling women. It is known that angiogenesis is a critical factor during follicular development. We and other investigators have explored the role of EMs in ovarian angiogenesis, particularly in human corpus luteum function, showing that 4-hydroxyestrone (4-OHE1) and 16-ketoestradiol (16-kE2) have pro-angiogenic effects while 2-methoxyestradiol (2-ME2) and 2-methoxyestrone (2-ME1) have anti-angiogenic effects. Additionally, 2-hydroxyestradiol (2-OHE2), which is produced in the ovary, has proliferative and pro-angiogenic properties. We hypothesized that EMs could be involved in angiogenesis necessary for ovarian follicular development in fertile women, and that dysregulation of these factors may contribute to follicular arrest in PCOS. The relationship between EMs, VEGF and AMH in the pathophysiology of follicular arrest in PCOS has not been previously studied at a follicular level in anovulatory women without ovulation induction. STUDY DESIGN, SIZE, DURATION: This is a comparative experimental study of serum and FF collected from different sized follicles (antral <10 mm and dominant >16 mm) of women with and without ovarian stimulation. The study included women with regular menstrual cycles who were proven to be fertile (n ¼ 20) and PCOS women with follicular arrest who were candidates for ovarian drilling (n ¼ 17), as well as other patients requiring ovarian stimulation, i.e. control women undergoing IVF for male factor infertility (n ¼ 12) and PCOS women undergoing IVF (n ¼ 17). In vitro studies were carried out on granulosa-lutein cells (GCs) obtained from subsets of women undergoing IVF for male factor infertility (n ¼ 6) and PCOS women undergoing IVF (n ¼ 6). GCs were maintained in culture for up to 6 days. PARTICIPANTS/MATERIALS, SETTING, METHODS: Intrafollicular estradiol, estrone and EMs concentrations were determined by high performance liquid chromatography-mass spectrometry. Testosterone in serum was measured by RIA, and LH, FSH and sex hormone-binding globulin in serum were measured with IRMA kits. AMH was determined in serum and FF by enzyme linked immunosor