Study of ovarian angiogenesis in Polycystic Ovary Syndrome (PCOS): Role of VEGF and Angiopoietins in a DHEA rat model.

D. ABRAMOVICH, G. IRUSTA, F. PARBORELL AND M. TESONE

Simposio; Sixteenth Annual Symposium. Frontiers in Reproduction; 2013

Introduction: Despite the advances in assisted reproduction, poor and high ovarian response to gonadotropins remains a problem. Patients who fail to obtain an adequate number of mature follicles after gonadotropin stimulation are considered to be poor responders. On the other hand, the retrieval of >15 oocytes is one of the main criteria for deeming a patient as high responder. In women, ovarian angiogenesis seems to be involved in the selection of follicles during stimulated IVF cycles. Gonadotropins, steroids and vasoactive substances such as vascular endothelial growth factor (VEGF) and angiopoietin-1 (ANGPT1) are involved in the regulation of vascularization. The ANGPTs/Tie-2 system acts in concert with VEGF. ANGPT-1 is necessary to stabilize blood vessels while ANGPT2 and the soluble receptor Tie-2 (sTie-2) act as natural antagonists for ANGPT1. The balance between ANGPT1, ANGPT2 and sTie-2, and VEGF is important for angiogenesis in the ovary. It is important to note that one of our previous reports demonstrated that levels of ANGPT1 were increased in follicular fluid (FF) from high responder patients undergoing ART in comparison with those from normoresponder patients. Our objectives were: 1) To analyze the levels of ANGPT1 and sTie-2 in FF from young poor responders and 2) To determine the effect of ANGPT1 in high responder patients undergoing ART on endothelial cell migration. Material and methods: This study was performed in 51 patients aged 25-39 years old undergoing ART. Written informed consent was given by all the patients before recruitment. Patients with pelvic pathologies such as endometriosis, uterine fibroids or pelvic inflammatory disease were excluded from the study. Patients were classified into three groups with respect to the number of aspirated oocytes: normoresponders (n=15; 8-13 oocytes), low responder (n=17; 0-5 oocytes) and high responder (n=19; 15-25 oocytes). The FF was centrifuged immediately for 10 min at 2000 x g to remove cellular components and debris and then transferred to sterile polypropylene tubes. The supernatant was stored at ?80º C until assayed. The levels of ANGPT1 and sTie-2 were measured in FF by ELISA assay. To assess the specific effect of ANGPT1 on ovarian angiogenesis, we evaluated the effect of FF from high responders on endothelial cell migration in the presence of a neutralizing antibody against ANGPT1. For this purpose, a wound healing assay using the EA.hy926 endothelial cell line was performed. Results: In FF from patients undergoing ART with poor response, the levels of ANGPT1 were higher than in normoresponders (Normoresponders: 165.1 ± 21.7 vs Poor responders: 318.5 ± 61.6 pg / ml, p