Effect of high ovarian response on the expression of endocrine gland-derived vascular endothelial growth factor (EG-VEGF) in peri-implantation endometrium in IVF women.

OBJECTIVE:To investigate the effect of ovarian stimulation on the expression of EG-VEGF mRNA and protein in peri-implantation endometrium in women undergoing IVF and its relation with endometrial receptivity (ER). DESIGN:Prospective laboratory study. SETTING:University hospital. PATIENTS:Eighteen women in stimulated cycles (SC) as study subjects and 18 women in natural cycles (NC) as controls. Women in SC group were classified with two subgroups, high ovarian response (SC1, n=9) with peak serum E2>5,000 pg/mL and moderate ovarian response (SC2, n=9) with peak serum E2 1,000-5,000 pg/mL. INTERVENTION(S):Endometrial biopsies were collected 6 days after ovulation in NC or after oocyte retrieval in SC. MAIN OUTCOME MEASURE(S):Endometrium histological dating was observed with HE staining. EG-VEGF mRNA expression levels determined by real-time polymerase chain reaction analysis, and protein levels by immunohistochemistry. RESULTS:All endometrial samples were in the secretory phase. The endometrial development in SC1 was 1 to 2 days advanced to NC, and with dyssynchrony between glandular and stromal tissue. Immunohistochemistry analysis showed that EG-VEGF protein was predominantly expressed in the glandular epithelial cells and endothelial cells of vessels, and also presented in the stroma. The image analysis confirmed that both the gland and stroma of endometrium in SC1 had a significantly lower EG-VEGF protein expression than that in SC2 and NC endometrium. Moreover, EG-VEGF mRNA levels were significantly lower in SC1 than in NC. Both EG-VEGF protein and mRNA levels had no significant difference between SC2 and NC. CONCLUSION:Decreased expression of EG-VEGF in the peri-implantation is associated with high ovarian response, which may account for the impaired ER and lower implantation rate in IVF cycles.