论文部分内容阅读
Ovarian stimulation during in vitro fertilization and embryo transfer increases the estradiol and progesterone levels in the luteal phase of the treatment cycle.High levels of these steroids reduces the success rate of the treatment via their actions on endometrial receptivity.Currently,there is no accurate method for determination of endometrial receptivity.Histological dating has been shown to be inaccurate.There is no single molecule that is acceptable for use as a biochemical marker for endometrial receptivity.The recently developed molecular biology approach with endometrial receptivity array can only be used in natural cycles or hormonal replacement cycles.In the literature,a trophoblast spheroid attachment assay has been described to assess endometrial receptivity.In this method,clumps of choriocarcinoma cells (spheroids) are used as embryo surrogates and cocultured with endometrial epithelial cells.The number of attached spheroids after coculture reflects endometrial receptivity.However,the choriocarcinoma spheroids attach to all types of cells and the specificity of the assay has been questioned.We have recently developed a new model for determining endometrial receptivity using the attachment assay.Instead of choriocarcinoma spheroids,we differentiate human embryonic stem cells into trophectoderm cells.These cells produce a blastocoel-like cavity when they are differentiated in clumps.They only attach to receptive endometrial epithelial cell lines but not to other non-endometrial epithelial cell lines,indicating specificity of their binding to receptive endometrium.More importantly,they attach to primary human endometrial epithelial cells from women 7 days after human chorionic gonadotrophin injection in a stimulated cycle,but not from those 2 days after injection.It is likely that they can be used as specific test for endometrial receptivity based on biological function of the endometrium being tested.