P-327 The impact of chronic endometritis disease on endometrial receptivity gene expression in women with repeated implantation failure

Abstract

Abstract Study question Does chronic endometritis (CE) have an impact on the expression of the genes involved in the embryo implantation? Summary answer The mRNA expression of genes involved in embryo implantation (HOXA10, HOXA11, BTEB1 and LIF) does not change in patients with and without CE. What is known already CE is an inflammatory disorder of the endometrium with a detrimental effect on embryo implantation and its prevalence in women with repeated implantation failure (RIF) is up to 30%. During the implantation window, the expression of some genes plays a key role in determining the success of embryo implantation. The homeobox genes HOXA10, HOXA11 and the basic transcriptional element binding protein 1 (BTEB1) gene are essential for endometrial cells growth regulation and for embryonic development and the leukaemia inhibitory factor (LIF) has a role in the embryo–endometrium interaction. Study design, size, duration A single centre-prospective case-control study was conducted at the Women’s and Children’s Health Department at Padua University, on infertile women with RIF from June 2020 to November 2021. 29 women with RIF were prospectively enrolled. Participants/materials, setting, methods An endometrial biopsy using a Novak curette was performed for each patient and the obtained tissue samples were divided in two aliquots, one for immunohistochemistry for histological examination (endometrial dating and CE diagnosis) and one for RNA extraction and gene expression analysis that has been performed using RT-PCR. Sample of patients with and without CE were compared using non-parametric Mann–Whitney U-test. A p-value <.05 was considered as statistically significant. Main results and the role of chance Enrolled women were divided in two groups according to the histological diagnosis of CE: 13 patients with CE, 16 without CE. In all samples, appropriate histological dating (WOI) was evaluated according to Noyes criteria. After the comparison of all investigated genes (HOXA10, HOXA11, BTEB1 and LIF), no significant difference in mRNA expression was detected between women with and without CE (p value >.05). In the literature, defective endometrial expression of HOXA10, HOXA11 and LIF genes has been associated with abnormal implantation and the reduced expression of BTEB1 gene results in subfertility and progesterone resistance. Although the negative role of CE in altering embryo implantation is known, our results suggest that the CE has no effect on the expression of HOXA10, HOXA11, BTEB1 and LIF genes. Probably the detrimental effect of CE on embryo implantation does not act through HOXA10, HOXA11, BTEB1 and LIF gene expression. Limitations, reasons for caution This is a non-randomized observational study with a limited number of patients. Further studies are needed to confirm our data with immunohistochemistry evaluation to define the protein expression levels of the investigated genes. Wider implications of the findings Understanding the pathogenic mechanism of CE on endometrial receptivity is crucial for identifying markers that best correlate with possible implantation failure and for identifying the appropriate therapy to treat the disease and restore the embryo implantation capacity. Trial registration number not applicable