OBJECTIVES: To perform a morphometric and ultrastructural analysis of the various cellular components that constitutes the endometrial epithelium during the implantation window. METHODS: Endometrial biopsies of six patients in ageing to procreate were realized during the implantation window and analyzed using light and transmission electron microscopy (TEM). RESULTS: During the implantation window, four endometrial cell types are identified in distinct proportions: microvilli-rich cells, pinopode cells, ciliated cells and others without apical differentiation. We highlighted important differences between surface and glandular epitheliums. Pinopode cells are present in all biopsies; they are more frequent in glands than surface. Their maximum expression in the glandular epithelium is at the day 20 and in the surface epithelium at the day 22. The pinopodes are present since day 19, they appeared fully developed with a maximum at day 22. Using TEM for ultrastructural analysis, we showed images of endocytosis and numerous secretory vesicles in epithelial cells of the endometrium. Their plasmic membrane present apical differentiations in the form of microvilli covered with a very developed cell coat indicating a high activity of exchange with the extracellular compartment. The endometrial cells exhibit extensive signs of communication between neighboring cells appeared to be preserved. CONCLUSION: Our data suggest each cell type and each cell structure as a very precise function in order to prepare the endometrium to be receptive.
OBJECTIVES: To perform a morphometric and ultrastructural analysis of the various cellular components that constitutes the endometrial epithelium during the implantation window. METHODS: Endometrial biopsies of six patients in ageing to procreate were realized during the implantation window and analyzed using light and transmission electron microscopy (TEM). RESULTS: During the implantation window, four endometrial cell types are identified in distinct proportions: microvilli-rich cells, pinopode cells, ciliated cells and others without apical differentiation. We highlighted important differences between surface and glandular epitheliums. Pinopode cells are present in all biopsies; they are more frequent in glands than surface. Their maximum expression in the glandular epithelium is at the day 20 and in the surface epithelium at the day 22. The pinopodes are present since day 19, they appeared fully developed with a maximum at day 22. Using TEM for ultrastructural analysis, we showed images of endocytosis and numerous secretory vesicles in epithelial cells of the endometrium. Their plasmic membrane present apical differentiations in the form of microvilli covered with a very developed cell coat indicating a high activity of exchange with the extracellular compartment. The endometrial cells exhibit extensive signs of communication between neighboring cells appeared to be preserved. CONCLUSION: Our data suggest each cell type and each cell structure as a very precise function in order to prepare the endometrium to be receptive.