Because sperm vacuoles were marked as zones without chromatin in the sperm nucleus, which may reflect underlying chromosomal or DNA defects, this study considered whether they influence the morphology and dynamics of early developmental events in preimplantation embryos. Oocytes were injected with spermatozoa of four classes, according to the number and size of vacuoles at 6000 magnification, and derived embryos were observed under time-lapse microscopy. For each embryo, the times of pronuclei appearance and disappearance and the first, second and third divisions were determined and related to its respective class of injected spermatozoa and its developmental stage. Embryos arising from normal class-I spermatozoa (without vacuoles) reached the 4-cell stage significantly earlier than embryos developed from class-IV spermatozoa (with large vacuoles and other abnormalities) (P = 0.012). Blastocysts from class-I spermatozoa required the shortest mean time for all developmental events in comparison with blastocysts from spermatozoa of other classes (with vacuoles). Blastocysts also showed significantly earlier first division than arrested embryos in embryos arising from class-I spermatozoa (P = 0.033). An insight into the developmental dynamics of embryo development according to morphology and head vacuoles of injected spermatozoa in morphologically selected sperm-derived embryos was observed for the first time. Sperm chromosomal anomalies and inherent DNA damage may interfere with early stages of zygote formation, syngamy and cell divisions. Because sperm vacuoles were marked as zones without chromatin in the sperm nucleus, which may reflect underlying chromosomal or DNA defects, we considered whether they influence the morphology and dynamics of early developmental events in preimplantation embryos. In this prospective study, oocytes were injected with spermatozoa of four classes according to the number and size of vacuoles at 6000 magnification, and derived embryos were observed by time-lapse microscopy. For each embryo, the times of pronuclei appearance and disappearance and first, second and third divisions were determined and related to its respective class of injected spermatozoa and its developmental stage. Embryos which developed from normally shaped spermatozoa of class I (without vacuoles) reached the 4-cell stage significantly earlier than embryos developed from spermatozoa of class IV (with large vacuoles and other abnormalities). Blastocysts developed from class-I spermatozoa required the shortest average time for all developmental events in comparison with blastocysts developed after injection of spermatozoa of other classes (with vacuoles). Blastocysts also showed significantly earlier first division than arrested embryos in embryos arising from class-I spermatozoa. This study suggests that preselection of spermatozoa under high magnification for intracytoplasmic sperm injection may be important in terms of early embryo developmental dynamics in patients with poor sperm morphology. An insight into the developmental dynamics of embryo development according to morphology and head vacuoles of injected spermatozoa in intracytoplasmic morphologically selected sperm injection-derived embryos was observed for the first time.
COBISS.SI-ID: 903596
Development of an objective and accurate test that could help choosing embryos with the highest chance of achieving pregnancy in IVF procedures is an important goal of reproductive medicine. For this purpose, cumulus cells (CC) gene expression is being studied in order to find biomarkers of pregnancy. Several published studies in recent years have proposed potential biomarkers of pregnancy expressed in CC however, the biomarkers proposed have mostly not been validated on an independent set of samples. The aim of this study was to analyse the expression of EFNB2, RGS2 and VCAN, genes that were proposed as biomarkers of pregnancy, in CC by qPCR. Gene expression was evaluated in 43 individual CC samples, derived from a highly homogenous group of 43 women. The same protocol for ovarian stimulation was used for all women and elective single embryo transfer was performed. Expression levels of RGS2 and VCAN did not differ between CC of implanted and non-implanted embryos. EFNB2 showed borderline higher expression in CC of non-implanted embryos, which is contradictory with previous studies. Altogether, we could not replicate the results of previous studies where EFNB2, RGS2 andVCAN were proposed as biomarkers of pregnancy on our set of CC samples.
COBISS.SI-ID: 1995948
In in vitro fertilization (IVF) cycles controlled ovarian hyperstimulation (COH) is established by gonadotropins in combination with gonadotropin-releasing hormone (GnRH) agonists or antagonists, to prevent premature luteinizing hormone (LH) surge. The aim of our study was to improve the understanding of gene expression profile of cumulus cells (CC) in terms ofovarian stimulation protocol and oocyte maturity. We applied Affymetrix geneexpression profiling in CC of oocytes at different maturation stages usingeither GnRH agonists or GnRH antagonists. Two analyses were performed: the first involved CC of immature metaphase I (MI) and mature metaphase II (MII) oocytes where 359 genes were differentially expressed, and the second involved the two GnRH analogues where no differentially expressed genes were observed at the entire transcriptome level. A further analysis of 359 differentially genes was performed, focusing on anti-Müllerian hormone receptor 2 (AMHR2), follicle stimulating hormone receptor (FSHR), vascular endothelial growth factor C (VEGFC) and serine protease inhibitor E2 (SERPINE2). Among other differentially expressed genes we observed a marked number of new genes connected to cell adhesion and neurotransmitters such as dopamine, glycine and Ž-Aminobutyric acid (GABA). No differential expression in CC between the two GnRH analogues supports the findings of clinical studieswhere no significant difference in live birth rates between both GnRH analogues has been proven.
COBISS.SI-ID: 432044
PurposeThe aim of our study was to determine whether there are any differences in the cumulus cell gene expression profile of mature oocytes derived from modified natural IVF and controlled ovarian hyperstimulation cycles and if these changes could help us understand why modified natural IVF has lower success rates.MethodsCumulus cells surrounding mature oocytes that developed to morulae or blastocysts on day 5 after oocyte retrieval were submitted to microarray analysis. The obtained data were then validated using quantitative real-time PCR.ResultsThere were 66 differentially expressed genes between cumulus cells of modified natural IVF and controlled ovarian hyperstimulation cycles. Gene ontology analysis revealed the oxidation-reduction process, glutathione metabolic process, xenobiotic metabolic process and gene expression were significantly enriched biological processes in MNIVF cycles. Among differentially expressed genes we observed a large group of small nucleolar RNAs whose role in folliculogenesis has not yet been established.ConclusionThe increased expression of genes involved in the oxidation-reduction process probably points to hypoxic conditions in modified natural IVF cycles. This finding opens up new perspectives for the establishment of the potential role that oxidation-reduction processes have in determining success rates of modified natural IVF.
COBISS.SI-ID: 1121708