Changes in receptivity epithelial cell markers of endometrium after ovarian stimulation treatments: its role during implantation window

Background: To compare the expression of receptivity markers in epithelial and stromal cells in the endometrium of ovulatory women and infertile with hypothalamic pituitary dysfunction (HPD), untreated or treated with clomiphene citrate (CC), or with recombinant follicle stimulating hormone (rFSH). Methods: Twelve control ovulatory and 32 anovulatory women, 22 of whom received ovulation induction with CC (n = 12) or rFSH (n = 10). Endometrial biopsies were obtained during the mid-secretory phase. Hormonal secretion was measured by chemiluminescence immunoassay, endometrial dating and cellular expression and distribution of receptivity proteins were evaluated by quantitative immunohistochemistry. Results: CC or rFSH treatments, modified the expression of epithelial receptivity markers, such as Glycodelin A, beta-catenin, CD166/ALCAM and IGF-1R, but not in stromal markers. Also, a change in their cell distribution was observed. Conclusions: Treatment of infertile women with HPD modified the expression and distribution of receptivity markers in the mid-secretory phase of the endometrium in epithelial but not stromal cells, which can help to explain changes in the receptivity of the endometrium during treatments and suggest an important role of these cells in the receptivity window.