Dynamics Of Embryo Development Research Articles

The importance of cytoplasmic strings during early human embryonic development.

Objectives: During human in vitro fertilisation (IVF) treatments, embryologists attempt to select the most viable embryos for embryo transfer (ET). Previously, embryos were evaluated based on light microscopic morphological parameters. However, this is currently accomplished by morphokinetic analysis of time-lapse recordings. This technique provides us the opportunity to observe cytoplasmic strings at the blastocyst stage. The aim of this work was to examine the relationship between the presence of cytoplasmic strings (CS) and the embryo viability in human in vitro fertilised embryos. Study design: Herein, we present an evaluation of the morphokinetic data on the development of embryos obtained during IVF treatments performed at the Division of Assisted Reproduction between December 2020 and March 2021. The dynamics of embryo development, embryo morphology, and morphokinetic scores generated by a time-lapse system were compared between the presence of cytoplasmic strings (CS+) and their absence (CS-) at the blastocyst stage. Results: The development of 208 embryos from 78 patients was examined. Moreover, 81.2% of the embryos had CS in the blastocyst stage; 77% of CS existed in embryos created by conventional IVF, while 86% of CS existed in embryos fertilised by intracytoplasmic sperm injection (ICSI) (p = 0.08). A greater number of CS+ embryos developed into a higher quality blastocyst (52.1% vs. 20.5%, p = 0.02). The morphokinetic score values characterising the development of embryos, such as Known Implantation Data Score (KIDScore) and Intelligent Data Analysis (iDAScore), were higher in CS+ groups (KID: 6.1 ± 2.1 vs. 4.7 ± 2.07; iDA: 8.0 ± 1.9 vs. 6.8 ± 2.3, p < 0.01). The dynamics of the early embryo development were similar between the two groups; however, CS+ embryos reached the blastocyst stage significantly earlier (tB: 103.9h vs. tB: 107.6h; p = 0.001). Conclusion: Based on our results, the number of embryos with cytoplasmic strings was higher than that without cytoplasmic strings, and its presence is not related to the fertilisation method. These embryos reached the blastocyst stage earlier, and their morphokinetic (KIDScore and iDAScore) parameters were better. All these results suggest that the presence of CS indicates higher embryo viability. The examination of this feature may help us make decisions about the embryos with higher implantation potential.

P-148 The importance of filopodia during early human embryonic development

Abstract Study question The aim of this study was to examine the relation between the presence of filopodia and the embryo viability in human in vitro fertilised embryos. Summary answer The presence of filopodia related to a faster blastocyst development, a better blastocyst quality and higher morphokinetic scores which indicates a higher embryo viability. What is known already Filopodia are involved in numerous cellular processes, for example cell migration, neuronal extension growth and during embryonic development. There is no uniform name to describe these cytoplasmic string structures in the literature. Beside the frequent presence in different cell functions, we have limited information about its function in human embryos. In the early 2000s, the occurrence of filopodia or cytoplasmic strings at the blastocyst stage was classified as a negative sign of embryo viability, but more recently, it has been described as a positive feature, however, the importance and clinical significance of this structure is still controversial. Study design, size, duration Evaluation of the morphokinetic data on the development of 208 embryos from 78 IVF cycles. Examination was carried out at the Division of Assisted Reproduction, Department of Obstetrics and Gynaecology, Semmelweis University, Budapest between December 2020 and March 2021. Participants/materials, setting, methods Embryos from both conventional IVF (cIVF) and intracytoplasmic sperm injection (ICSI) treatments were analysed and evaluated. The dynamics of embryo development, embryo morphology and morphokinetic scores generated by time-lapse system was compared between the embryos with filopodia (FP+) and embryos without filopodia- (FP-) groups. Main results and the role of chance 81.2% of the embryos had filopodia in blastocyst stage. Embryos created by cIVF had 77%, while embryos fertilised by ICSI had 86% of filopodia presence (p = 0.08). FP+ embryos developed in a greater number into a higher quality blastocyst (52.1% vs 20.5%, p = 0,02), their KIDScore was higher (6.1 ± 2.1 vs 4,7 ± 2,07, p &amp;lt; 0.001) and they showed a tendency of higher implantation rate (39.7% vs 14.3% p = 0.16) than the FP- group. The dynamic of the early embryo development was similar between the two groups, however, FP+ embryos reached blastocyst stage significantly earlier (tB: 103.9 hours vs. tB: 107.6 hours; p = 0.007). Based on our results, there was a higher number of embryos with filopodia than without, and the presence of it is not related to the fertilisation method. These embryos developed faster into a blastocyst stage, their morphokinetic parameters were better. KIDScore and iDAScore embryo evaluation systems also recommend in a greater number the FP+ blastocysts for ET. We could also observe vesicle like transport along the filopodia, which leads us to believe that there might be a molecular communication between the differentiating cell populations. Limitations, reasons for caution Due to the low number of cases, the higher implantation rate is not significant. Wider implications of the findings The examination of this feature improves our knowledge of the early embryonic development and may help us to make decisions about the embryos with higher implantation potential. Trial registration number Not applicable

Evaluation of trace metals in follicular fluid in ICSI-treated patients

This study investigated the influence of cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), selenium (Se), and zinc (Zn) in follicular fluid on the effectiveness of in vitro fertilization (IVF) treatment and the dynamics of embryo development. The study involved 221 women aged 25-35 years in whom intracytoplasmic sperm injection (ICSI) was performed. Analysis of the effects of the average concentrations of Se, Zn, and Cu on the evelopmental dynamics of embryos showed that higher concentrations of these metals were accompanied by shorter lead times for each of the various stages of development, while the reverse was true in the case of cadmium and lead. No relationship was observed between the mean concentrations of Fe and the dynamics of the human embryo. In order to discover whether the fact of becoming pregnant is affected by the investigated variables, a logistic regression model was applied. The dependent variable was the fact of achieving pregnancy, and the independent variable tested was the level of trace metals. Ultimately, only one variable remained statistically significant in the model: the level of Se.

Using time lapse monitoring of embryo development (TLMED) in reproductive biotechnology

An increasing interest in assisted reproductive technologies and their applications in biotechnology of animal reproduction is currently observed. The development of in vitro fertilization (IVF) has led to the emergence of new techniques as ICSI (Intracytoplasmic Sperm Iniection), 1MSI (Morphologically Selected Intracytoplasmic Sperm Iniection) and PGS (Pre–Implantation Genetic Screening). Recently a new technology TLMED (Time Lapse Monitoring of Embryo Development), which allows to observe dynamics of embryo development is being introduced to practice. The application of this technique allows to determine the morphokinetics parameters of normal embryos and to observe its development more accurately. Currently, there are four systems in the market based on this technique: Primo Vision (Vitrolife, Sweden), EEVA (Auxogyn, USA), Embryoscope (Vitrolife, Sweden), MIRI (Esco, Denmark), which conducting the morphokinetics analysis of embryos, which ensures selection of the best embryos and increases the effectiveness of in vitro fertilization. The first positive results of the use of system TLMED in agriculture biotechnology on the example of the Biomedical Research Center of the Warsaw University of Life Sciences predicts its introduction into the everyday practice of veterinary clinics. The aim of this paper is to present each system and review the existing information about the possible application of TLMED and the usefulness in animal reproductive biotechnology.

Time-lapse monitoring of zona pellucida-free embryos obtained through in vitro fertilization: a retrospective case series

To report time-lapse monitoring of human oocytes in which the damaged zona pellucida was removed, producing zona-free (ZF) oocytes that were cultured until the blastocyst stage in time-lapse incubators. Retrospective case series. Private infertility clinic. Infertile patients (n = 32) undergoing minimal ovarian stimulation or natural cycle IVF treatment between October 2012 and June 2014. Intracytoplasmic sperm injection (ICSI) fertilization of ZF oocytes, prolonged embryo culture in time-lapse incubators, elective vitrification, and subsequent single vitrified-thawed blastocyst transfer (SVBT). Rate of fertilization, cleavage and blastocyst development, live-birth rate per SVBT cycle. In spite of advanced maternal age (39 ± 4.2; range, 30-46 years), good fertilization (94%), cleavage (94%), and blastocyst development rates (38%) were reached after fertilization and culturing of ZF oocytes/embryos. All thawed ZF blastocysts survived, and up to this date seven SVBT transfers were performed, yielding three (43%) term live births with healthy newborns. Time-lapse imagery gives a unique insight into the dynamics of embryo development in ZF embryos. Moreover, our case series demonstrate that an oocyte with a damaged zona pellucida that has been removed could be successfully fertilized with ICSI, cultured until blastocyst stage in a time-lapse incubator and vitrified electively for subsequent use.

The use of time lapse photography in an in vitro fertilization programme for better selection for embryo transfer.

The time lapse photography is not a new method for assessing the dynamics of early embryo development in vitro. It has been used many times in the past for studying cleavages and blastulation of embryos of various animal species. However, this technique became available for routine use in an human in vitro fertilization (IVF) programme only a couple years ago and it becomes more and more popular today. The new time lapse systems are using modified microscopes which are positioned within the incubators. The observation of embryos does not need the opening of incubators. By sequential photographing of each embryo separately with camera of low intensity illumination, more than 1400 pictures of embryo are made. All these pictures are collected together and transformed into a short movie with software. This system offers the observation of dynamics of embryo development. The studies, which have used a time lapse technique for studying embryo development, revealed that the timing between different events can be used for predicting its developmental potential. In this paper the advantages and drawbacks of time lapse photography is precisely described. An overview through the published papers analyzing the dynamics of human embryo development from the zygote toward blastocyst is done and new timing parameters for grading zygotes, early embryos and blastocysts are analyzed.

Impact of highly purified versus recombinant follicle stimulating hormone on oocyte quality and embryo development in intracytoplasmic sperm injection cycles

The quality of oocytes and developing embryos are the most relevant factors determining the success of an in vitro fertilization (IVF) treatment. However, there are very few studies analyzing the effects of different gonadotrophin preparations on oocyte and embryo quality. A retrospective secondary analysis of data collected from a prospective randomized study was performed to compare highly purified versus recombinant follicle stimulating hormone (HP-FSH vs. rFSH). The main outcome measures were quantity and quality of oocytes and embryos, dynamics of embryo development, cryopreservation, clinical pregnancy and live birth rate. The number of retrieved and of mature (MII) oocytes showed no significant differences. Fertilization rate was significantly higher in the HP-FSH group (68.9% vs. 59.9%, p = 0.01). We also found significantly higher rate of cryopreserved embryos per all retrieved oocytes (23.4% vs. 14.5%, p = 0.002) in the HP-FSH group. There were no significant differences in clinical pregnancy and in live birth rates. Oocytes obtained with HP-FSH stimulation showed higher fertilisability, whereas pregnancy and live birth rates did not differ between the groups. However, patients treated with HP-FSH may benefit from the higher rate of embryos capable for cryopreservation, suggesting that cumulative pregnancy rates might be higher in this group.

Dynamics of human embryo development in two types of blastocyst media: a prospective trial on sibling oocytes

Background: There is a lack of clinical trials on the success of embryo culture in different commercial culture systems in the programme of in vitro fertilization (IVF). In our prospective study, embryo development was compared in two sequential media. Methods: The oocytes from each of 62 patients, treated by IVF/ICSI, were distributed into two groups for 5-day culture in the BlastAssist® System (Medicult, Denmark) (Group 1, n = 421) and in the GIII Series™ (Vitrolife, Sweden) (Group 2, n = 415) media. The dynamics of embryo development, implantation and pregnancy rates were compared between groups. Results: The differences between Groups 1 and 2 were first noted on day 3 when GIII yielded more fast-cleaving (> 6 cells) nonfragmented embryos (31.3 % vs. 44.4 %, P < 0.01). On day 4 however, a larger number of compact embryos was found in Group 1 (42.2 % vs. 28.7 %, P < 0.005). The percentage of blastocysts or compact morulae on day 5 was the same in both groups (59.6 % vs. 55.6 %). But expanded blastocysts of optimal quality with oval inner-cell-mass developed more frequently in Group 1 (29.2 % vs. 17.7 %, P < 0.05), and therefore more transfers were performed exclusively with Group 1 embryos (28 vs. 17). Pregnancy and implantation rates were the same in both groups (53.6 % vs. 52.9 % and 34.7 % vs. 34.2 %, respectively). Conclusions: Although the GIII Series™ yields more fast-cleaving embryos on day 3, embryo compaction (morula) and cavitation (blastocoel) start earlier in the BlastAssist® System media. BlastAssist® System therefore allows easier selection of embryos for transfer on day 5.

Bayesian classification for the selection of in vitro human embryos using morphological and clinical data

In vitro fertilization (IVF) is a medically assisted reproduction technique that enables infertile couples to achieve successful pregnancy. Given the uncertainty of the treatment, we propose an intelligent decision support system based on supervised classification by Bayesian classifiers to aid to the selection of the most promising embryos that will form the batch to be transferred to the woman’s uterus. The aim of the supervised classification system is to improve overall success rate of each IVF treatment in which a batch of embryos is transferred each time, where the success is achieved when implantation (i.e. pregnancy) is obtained. Due to ethical reasons, different legislative restrictions apply in every country on this technique. In Spain, legislation allows a maximum of three embryos to form each transfer batch. As a result, clinicians prefer to select the embryos by non-invasive embryo examination based on simple methods and observation focused on morphology and dynamics of embryo development after fertilization. This paper proposes the application of Bayesian classifiers to this embryo selection problem in order to provide a decision support system that allows a more accurate selection than with the actual procedures which fully rely on the expertise and experience of embryologists. For this, we propose to take into consideration a reduced subset of feature variables related to embryo morphology and clinical data of patients, and from this data to induce Bayesian classification models. Results obtained applying a filter technique to choose the subset of variables, and the performance of Bayesian classifiers using them, are presented.