To determine the most informative markers for assessing the functional state of endometrium during the 'window of implantation' and creating a model for assessment of the readiness of endometrium for embryo implantation. Forty-seven women with tubal infertility and a successful IVF pregnancy participated in the study. Pipelle endometrial sample was performed during the supposed 'window of implantation' in natural cycle with subsequent histological study, and transcriptional profile of genes GPX3, PAEP, DPP4, TAGLN, HABP2, IMPA2, AQP3, HLA-DOB, MSX1, POSTN determined by real-time quantitative polymerase chain reaction (qRT-PCR). Differences in the level of mRNA expression of all the studied genes in the receptive endometrium were found in comparison to the prereceptive one, which allowed us to classify two functional states of the endometrium. The results of histological examination responded to the stage of maturation of the endometrium in 78.7% of cases. Receptive endometrial status can be determined based on the integral evaluation of mRNA expression level of 4 PAEP, DPP4, MSX1, and HLA-DOB genes. The model for determining a personalized `window implantation' is offered for practical application in ART.

We studied the relationship between the levels of protamines 1 and 2 (PRM1 and PRM2) and fertilin-β (ADAM-2) mRNA expression and outcomes of infertility treatment using assisted reproductive technologies was studied. Analysis of the relationships between the outcomes of in vitro fertilization and embryo transfer and profiles of the expression of seminal genes PRM1, PRM2, ADAM-2 mRNA, evaluated by reverse transcription quantitative PCR was carried out in 79 couples. Significant differences in the expression of seminal PRM1, PRM2, ADAM-2 mRNA were detected in couples with different outcomes of in vitro fertilization and embryo transfer. The levels of seminal gene expression are potential predictors of the efficiency of in vitro fertilization and embryo transfer.

Most studies have considered the negative influence of obesity on fertility in both genders. In the present study, we assessed mitochondrial activity expressed as the mitochondrial potential index (MPI) in cumulus cells from obese women and women with a normal body mass index (BMI) during assisted reproductive therapy. The results revealed a significant reduction of MPI with increased body mass. The lower MPI levels in cumulus cells from obese women may reflect mitochondrial dysfunction caused by oxidative stress, which can affect the cumulus-oocyte complex and have an impact on oocyte development.

The expression of mRNA of 36 genes involved in implantation was studied by reverse transcription and real-time PCR. Significant differences in mRNA expression during the early and middle stages of the secretion phase were detected for genes mmp7, vegf, il2m, il1β, il8, il18, tnfα, il10, tgfβ, igfbp2, etc.

The aim of this study was to determine the changes of metabolomic profiles in embryonic culture media (ECM) for the evaluation of quality and implantation potential of human embryos. ECM (n=163) were collected on day 5 before transfer or cryopreservation. Some embryos were used in preimplantation genetic screening for detection of aneuploidy karyotypes. Samples were subdivided into groups according to embryo morphological classification (by Gardner), genetic analysis and implantation data. ECM were extracted with methanol, precipitates were separated by centrifugation and metabolite production of individual embryo was analysed by LC-MS (the positive ion mode). After peak detection and retention time alignment, data were analysed using the PCA algorithm. MS fingerprinting analysis of embryo culture medium showed significant differences between morphologically divided groups. Intragroup comparisons did not reveal differences between subclasses. Genetic screening of embryos revealed 33 aneuploid karyotypes. It was shown that chromosome number did not affect the metabolite profiles comparing with the normal group. The culture media of embryos that were positive or negative for successful implantation showed specific signatures that allowed to distinguish embryos with different outcomes.The characterization of ECMs by LC-MS may facilitate more accurate selection of the best embryo for the implantation, improving single-embryo transfer and thus eliminating the risk and undesirable effects of multiple pregnancies.