Ovarian Stimulation Affects the Levels of Regulatory Endometrial NK Cells and Angiogenic Cytokine VEGF

Problem Endometrial NK cells play a critical role in uterine vascularization producing angiogenic factors. Impact of ovarian stimulation on endometrial expression of NK cells and VEGF in normal fertile oocyte donors and the effect of endometrial injury treatment on these parameters have been investigated. Method of study Endometrial tissue was obtained from oocyte donors during natural and stimulated cycles. NK cell subsets were measured by flow cytometry. VEGF was determined by ELISA and flow cytometry. Endometrial angiogenic parameters were determined by ultrasound Doppler. Local injury was induced by scratching endometrial tissue previous to implantation window. Results Ovarian stimulation decreased endometrial levels of NK cells and vascularization index but increased VEGF levels. Local injury normalized only the CD56+ NK cell count. Conclusion Hormonal therapy for ovarian stimulation may be associated with poor endometrial vascularization. Local injury before the implantation window seems not to influence endometrial angiogenic parameters altered by ovarian stimulation.