Ultrastructural markers of tissue endometrial receptivity in patients with recurrent implantation failure

Abstract

The scanning electron microscopy of the endometrial surface epithelium during the 'implantation window' was performed in 119 patients with uterine factor of infertility or recurrent miscarriage due to endometrial hypoplasia. Ultramorphological picture of the surface endometrial epithelium was characterized by aplasia and hypoplasia of pinopodes (67.39%), dense cellcell contacts (69.53%), heteromorphy of secretory cells (15.22%) in combination with atypia of microenvironment cells (50%) in patients with infertility. The asynchronous development of pinopodes (46.67%) and the absence of intercellular contacts separation during the 'implantation window' (84.44%) was observed in patients with recurrent miscarriage. The revealed disturbance determines the mechanisms of the blastocyst adhesion violation and trophoblast invasion in the different stages of implantation in patients with uterine factor of infertility and recurrent miscarriage.

Organoids of Human Endometrium: A Powerful In Vitro Model for the Endometrium-Embryo Cross-Talk at the Implantation Site

“…The pinopodes' cytoplasm is characterized by the presence of a low number of organelles while containing numerous coated vesicles, microfilaments, glycogen aggregates and small mitochondria. Analogously to what is reported in vivo, the pinopodes developed by these in vitro cultured organoids are characterized by the presence of well-defined cell separation, another feature reported to be an essential condition for embryo implantation and invasion [33].…”