Meiotic errors during oocyte maturation are the primary cause of embryonic aneuploidy. Coordinated functioning of the cytoskeleton and its associated contractile proteins is essential for karyokinesis and cytokinesis. This review summarizes studies investigating the roles of actin, myosin, and kinesin in mouse and human oocyte maturation. Mechanisms underlying the involvement of contractile proteins in oocyte maturation are described. Specifically, actin participates in spindle assembly during the first and second meiotic divisions by stabilizing K-fibers. Cytoplasmic actin, together with myosin-5b and myosin-2, mediates the migration and orientation of the meiotic spindle to the periphery, driving asymmetry in human oocytes; in mouse oocytes, actin and myosin-5b are also responsible for central positioning of the nucleus in prophase I. Polar body extrusion occurs via contraction of the actomyosin contractile ring. Kinesins are also widely represented in oocyte maturation processes. In mouse oocytes, Kif11, Kif16A, and Kif16B contribute to spindle formation and stabilization, whereas KifC1 stabilizes kinetochore fibers (K-fibers). Additionally, Kif16A and Kif16B regulate cell cycle progression by modulating spindle assembly checkpoint activation and the G2–M meiotic transition, respectively. In human oocytes, HSET (kinesin-14) is responsible for spindle pole determination, and Kid (kinesin-10) is involved in chromosome alignment at the metaphase plate.
Objective: The aim of this study is to compare the prognostic significance of the KIDScore, PGT-A, and MitoScore assessment systems in relation to the probability of embryo implantation at the blastocyst stage, pregnancy outcomes, and obstetric complications in ART cycles. Materials and Methods: The study conducted a retrospective analysis of embryological protocols and the results of PGT-A. In euploid embryos, the mitochondrial DNA MitoScore was assessed. The clinical outcomes of the resulting pregnancies were evaluated. Results: It was found that higher KIDScore values were more often determined in euploid embryos. When analyzing the relationship between KIDScore and MitoScore, no statistically significant dependence was found. However, there was a tendency towards a higher frequency of low and medium MitoScore values among embryos in groups with medium and high KIDScore values. In our study, we found a statistically unconfirmed tendency towards a higher frequency of clinical pregnancies and live births in the group of patients who underwent embryo transfer with high KIDScore and medium MitoScore values. There was an increase in the percentage of complicated pregnancies after embryo transfer with low KIDScore values. In our study, the most common obstetric complications were preeclampsia and gestational diabetes mellitus. Conclusions: The obtained data allow us to consider the cultivation of embryos using video surveillance in combination with the assessment of the implantation potential of embryos based on artificial intelligence technologies as a non-invasive tool for predicting the chromosomal status of the embryo, as well as to use this technique as an additional tool when selecting an embryo for transfer into the uterine cavity. Proper integration of the KIDScore, PGT-A, and MitoScore embryo assessment systems can help improve the accuracy of selecting an embryo with the highest potential for implantation, which is crucial for implementing a personalized approach to patients and transferring a single embryo to prevent multiple pregnancies and their associated complications.
Background: Elevated levels of sperm DNA fragmentation can negatively affect outcomes of assisted reproductive technology programs, making the selection of spermatozoa with intact genetic material a critical step. Microfluidic technologies can provide selection of spermatozoa with low levels of DNA damage. Objective: To compare the DNA fragmentation index in spermatozoa from native ejaculate, after density gradient centrifugation, and after microfluidic selection (SPRINT chip) using a Sperm-Cyto flow cytometer. Materials and methods: The study included 25 men of reproductive age (mean age 37 years). Ejaculate samples were analyzed according to standard protocols and divided into groups: native sample, spermatozoa after density gradient centrifugation, and spermatozoa after selection on the SPRINT microfluidic chip. In each group, the DNA fragmentation index was assessed using the SCSA (Sperm Chromatin Structure Assay) method with a Sperm-Cyto flow cytometer. Results: Microfluidic selection provided the selection of spermatozoa with a low DNA fragmentation index (2.30 ± 1.78
Azoospermia is defined as the absence of spermatozoa in the ejaculate after centrifugation. This condition represents one of the most severe causes of male infertility. The prevalence of azoospermia is up to 1
Background: Infertility represents a global medical and social problem, and endometrial dysfunction (thinning, impaired receptivity, synechiae, etc.) remains one of the key causes of implantation failure and limitation of the effectiveness of assisted reproductive technology (ART) programs. In this regard, new pathogenetic approaches are being actively investigated, among which cell technologies occupy a special place. Objective: To analyze current scientific literature data on the potential of mesenchymal stromal cells derived from menstrual blood (MenSCs) for restoring functional activity of the endometrium and improving the effectiveness of ART programs. Materials and methods: This review summarizes the results of fundamental research, preclinical trials on animal models, and early clinical studies on the isolation, cultivation, phenotyping, and transplantation of human MenSCs. The review includes data from foreign and Russian articles found in Pubmed, Elsevier, and Cochrane Library databases on this topic, published over the last 7 years. Results: Literature analysis confirms that menstrual blood is an accessible and reproducible non-invasive source of MSC cells with a phenotype and properties consistent with the criteria of the International Society for Cell Therapy (ISCT). MenSCs demonstrate high proliferative potential, multilineage differentiation capacity, and pronounced paracrine activity directed toward angiogenesis and modulation of endometrial receptivity. Based on recent studies, the safety profile of MenSCs is assessed as favorable. Conclusion: Further research in this area is needed to standardize protocols for cell isolation and transplantation, and ultimately to use optimized methods in clinical practice of ART programs to increase implantation and pregnancy rates.
