Effects of ovarian stimulation on endometrial integrin β3 and leukemia inhibitory factor expression in the peri-implantation phase

Use of the natural cycle and vitrification thawed blastocyst transfer results in better in-vitro fertilization outcomes

“…The microenvironment of the endometrium is primarily regulated by the ovarian steroid hormones, estrogen and progesterone. Indeed, the expression of potential implantation markers such as endometrial integrin β3 subunit and leukemia inhibitory factor (LIF) was significantly reduced in the presence of supraphysiologic concentrations of estrogen [12,13]. Although several candidate molecules are under active investigation, the roles played by these factors in implantation are currently not fully known.…”

“…Although several candidate molecules are under active investigation, the roles played by these factors in implantation are currently not fully known. However, abundant evidence suggests that genes highly expressed during the WOI of a natural cycle tend to be downregulated at higher estrogen concentrations [12][13][14][15][16]. Therefore, patients with normal ovarian function may achieve the best results using natural rather than hormonally manipulated cycles, because exogenous estrogen may alter the physiologic concentration of endogenous hormone, resulting in negative effects on the endometrium [7,15].…”

Endometrial Receptivity and Human Embryo Implantation

“…It also appears from human IVF-ET reports that the ratio of progesterone to estrogen in circulation is critical for the secretory maturation of the endometrial glands during the mid-luteal phase and high level of estrogen may adversely affect endometrial receptivity and inhibit implantation. [15][16][17] It has also been shown that luteal phase ovarian estrogen is not essential for blastocyst implantation in the human. 18 Animal models also prove this concept.…”

Calcium-binding protein S100P is highly expressed during the implantation window in human endometrium

“…Clinical studies in an oocyte donation program showed that E 2 levels more than 2,500 pg/mL resulted in a significantly reduced implantation rate, although embryo quality was not affected (23). Chen et al (24) showed that endometrial integrin b3 and luekemia inhibitory factor (LIF) expression in the peri-implantation phase was significantly lower in COH cycles than in untreated controls, which assumed that endometrial receptivity is negatively impaired in COH cycles compared with natural cycles. All of these lines of evidence support the speculation that S100P was closely associated with the implantation window.…”