Role of vimentin in the morphogenesis of endometrial decidualization during pregnancy with IVF methods

Abstract

BACKGROUND: Early reproductive loss is a complex problem, the solution of which requires a systematic approach to the study of the morphogenesis of gravid transformation. Violations of the morphofunctional characteristics of the endometrium are associated with chronic endometritis, which entails implantation pathology and the development of pregnancy, while formulating indications for the use of IVF methods. Chronic endometritis disrupts the differentiation of stromal cells and intermediate filaments with subsequent pathology of decidualization and gravid transformation. AIM: The aim of this study was to evaluate vimentin expression in decidual cells of the gravid endometrium in an undeveloped first-trimester pregnancy after IVF, depending on its transformation in patients with chronic endometritis. MATERIALS AND METHODS: Histological and immunohistochemical studies were performed on 40 samples of abortion material with normal chorionic villi karyotype from a non-developing pregnancy after IVF in patients with chronic endometritis and 15 samples of abortion material from a progressive pregnancy, surgically terminated at the woman’s request at similar terms. Two groups were formed — I group with a full-fledged gravid transformation in a non-developing pregnancy after IVF (n = 20) and II group with an incomplete gravid transformation in a non-developing pregnancy after IVF (n = 20). Histological examination was performed according to the standard procedure. Immunohistochemical study was performed using a one-step protocol with antigen unmasking. Primary monoclonal antibodies to vimentin (Clon V9, Diagnostic BioSystems Inc., Spain) were used at a 1 : 1000 dilution. Vimentin expression was evaluated in the compact layer of the gravid endometrium. RESULTS: A full-fledged gravid transformation of the endometrial stroma in the abortion material in study group I and the control group was represented by mature deciduocytes of the epithelioid type, round or polygonal in shape, with a light vesicular nucleus. With an incomplete gravid transformation, the compact layer of the gravid endometrium was represented by fibroblasts with varying degrees of cytoplasmic development, from mild changes to the formation of pre-decidual and immature decidual cells. A decrease in vimentin expression was verified in the gravid endometrium after IVF compared to the control group. In case of an incomplete gravid transformation, a decrease in vimentin expression was also verified compared to the control group and study group I. CONCLUSIONS: The presence of chronic endometritis in patients with infertility and chronic endometritis not only causes pathology of the original endometrium, but also disrupts decidualization, leading to reproductive loss with normal embryo karyotype.