Objective: During reproductive age of a woman, endometrium undergoes frequent stuctural and functional changes. Abilities of regeneration, remodelation and differentiation are precondition of endometrial receptivity and implantation and development of an embryo. These processes are conditioned by mutual transformation between mesenchymal and epithelial fenotype of endometrial cells: epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET). The aim of this study is to present contemporary knowledge of transformation between epithelial and mesenchymal endometrial cells and its influence on human fertility.
Design: Review article.
Setting: Department of Obstetrics and Gynecology, Faculty of Medicine, Masaryk university and University Hospital Brno; Department of Obstetrics and Gynecology, University Hospital Faculty of Medicine, Palacky University, Olomouc.
Methods: PubMed was searched for articles in English indexed until February 2019 with terms of „endometrial receptivity“, „embryo implantation“, „endometrial regeneration“, „mesenchymal-epithelial transition/transformation“.
Results: It has been proved, that mesenchymal stromal cells participate on regeneration of not only the endometrial stroma, but also of the epithelium. During endometrial decidualisation under influence of ovarian steroids, the MET is under way. Stromal fibroblasts gain the morfological and functional properties of epithelial cells. During implantaion of an embryo, the trofoblast interacts with decidualised endometrium. Epithelial cells transform into mesenchymal (EMT), which mediate the growth of trofoblast.
Conclusion: Mutual transformation between stromal and epithelial cells in essential for normal function of endometrium and implantation and development of an embryo.
Keywords: embryo implantation; endometrial receptivity; endometrial regeneration; endometrium; mesenchymalepithelial transition.