Does endometriosis inflict harm on embryos? A systematic review of embryo morphokinetics analysed by time lapse monitoring in women with endometriosis.

Endometriosis has been shown to be associated with unfavorable development and maturation of oocytes, as well as aberrancies in embryonal development, including arrest after fertilization, following in vitro fertilization (IVF). Time-lapse monitoring (TLM) enables continuous and non-invasive monitoring of embryo morphokinetics during the IVF process and might be useful in the assessment of embryos from women with endometriosis. In this review, five eligible studies were evaluated to determine if embryo morphokinetics assessed under TLM differ in patients with endometriosis and subsequently predict blastocyst quality, implantation and success of pregnancy. The studies showed overall inferior morphokinetic parameters of embryos from endometriosis patients when compared to controls, independent of the severity of endometriosis. Embryos with optimal early morphokinetic parameters (t2, s2, t5, tSB, tEB) and late developmental events (compaction, morulation, and blastulation) had better implantation rates than those who had suboptimal ranges. However, due to few studies available with mostly retrospective data, the validity of these findings and their generalizability for clinical practice needs to be further assessed. Prospective studies with larger sample sizes are needed to determine whether using TLM for embryo selection in endometriosis improves pregnancy and live birth outcomes.

Using blastocyst re-expansion rate for deciding when to warm a new blastocyst for single vitrified-warmed blastocyst transfer.

RESEARCH QUESTION: Can predictive post-warm parameters that support the decision to transfer a warmed blastocyst or to warm another blastocyst be identified in women with multiple frozen-vitrified blastocysts? DESIGN: Retrospective single-centre observational cohort analysis. A total of 1092 single vitrified-warmed blastocyst transfers (SVBT) with known Gardner score, maternal age and live birth were used to develop live birth prediction models based on logistic regression, including post-warm re-expansion parameters. Time-lapse incubation was used for pre-vitrification and post-warm embryo culture. A dataset of 558 SVBT with the same inclusion criteria was used to validate the model, but with known clinical pregnancy outcome instead of live birth outcome. RESULTS: Three different logistic regression models were developed for predicting live birth based on post-warm blastocyst re-expansion. Different post-warm assessment times indicated that a 2-h post-warm culture period was optimal for live birth prediction (model 1). Adjusting for pre-vitrification Gardner score (model 2) and in combination with maternal age (model 3) further increased predictability (area under the curve [AUC] = 0.623, 0.633, 0.666, respectively). Model validation gave an AUC of 0.617, 0.609 and 0.624, respectively. The false negative rate and true negative rate for model 3 were 2.0 and 10.1 in the development dataset and 3.5 and 8.0 in the validation dataset. CONCLUSIONS: Clinical application of a simple model based on 2 h of post-warm re-expansion data, pre-vitrification Gardner score and maternal age can support a standardized approach for deciding if warming another blastocyst may increase the likelihood of live birth in SVBT.

Stratifying Cumulus Cell Samples Based on Molecular Profiling to Help Resolve Biomarker Discrepancies and to Predict Oocyte Developmental Competence.

To increase the efficiency of assisted reproductive techniques (ART), molecular studies have been performed to identify the best predictive biomarkers for selecting the most suitable germ cells for fertilization and the best embryo for intra-uterine transfer. However, across different studies, no universal markers have been found. In this study, we addressed this issue by generating gene expression and CpG methylation profiles of outer cumulus cells obtained during intra-cytoplasmic sperm injection (ICSI). We also studied the association of the generated genomic data with the clinical parameters (spindle presence, zona pellucida birefringence, pronuclear pattern, estrogen level, endometrium size and lead follicle size) and the pregnancy result. Our data highlighted the presence of several parameters that affect analysis, such as inter-individual differences, inter-treatment differences, and, above all, specific treatment protocol differences. When comparing the pregnancy outcome following the long protocol (GnRH agonist) of ovarian stimulation, we identified the single gene markers (NME6 and ASAP1, FDR < 5%) which were also correlated with endometrium size, upstream regulators (e.g., EIF2AK3, FSH, ATF4, MKNK1, and TP53) and several bio-functions related to cell death (apoptosis) and cellular growth and proliferation. In conclusion, our study highlighted the need to stratify samples that are very heterogeneous and to use pathway analysis as a more reliable and universal method for identifying markers that can predict oocyte development potential.

Prospective randomized multicentre comparison on sibling oocytes comparing G-Series media system with antioxidants versus standard G-Series media system.

RESEARCH QUESTION: Does the inclusion of three antioxidants (A3), acetyl-l-carnitine (ALC), N-acetyl-l-cysteine (NAC) and alpha-lipoic acid (ALA) improve human embryo development and pregnancy potential? DESIGN: Prospective randomized multicentre comparison of sibling oocytes. A total of 1563 metaphase II oocytes from 133 patients in two IVF centres. Day 3 embryo and day 5/6 blastocyst quality were assessed. Good embryo quality on day 3 was defined as 8 to 10 cells with even cells and low fragmentation; good quality blastocysts as 3BB or greater. Clinical outcome was assessed on transfers of fresh or vitrified-warmed blastocyst on day 5. RESULTS: Of the two-pronuclei, 40.7% (G-Series) and 50.2% (G-Series with A3 group) resulted in good quality embryos on day 3 (P < 0.05). The implantation rate by fetal sac was 39.2% and 50.6%, and by fetal heartbeat was 37.8% and 47.1% for the G-Series and G-Series with A3 group, respectively. When stratified by female patient age, patients 35-40 years had an implantation rate by fetal sac and heart of 23.5% in the G-Series compared with 57.5% (P < 0.05) and 50.0% (P < 0.05) in the A3 group. The ongoing pregnancies in patients 35-40 years were significantly higher in the A3 group (50%) compared with the control (25.8%) (P < 0.05). CONCLUSIONS: The presence of antioxidants during IVF and embryo culture for patients 35-40 years resulted in a significant increase in implantation and pregnancy rate. Supplementation of antioxidants to IVF and culture media may therefore improve the viability of human embryos in assisted reproductive technologies, plausibly through the reduction of oxidative stress.

Blastomere movement post first cell division correlates with embryonic compaction and subsequent blastocyst formation.

BACKGROUND: Blastomere movement (BMov) occurs after the first cell division in human embryos. This movement has been suggested as a prognostic parameter for pregnancy outcome prediction following cleavage-stage embryo transfer. However, the effect of BMov on preimplantation development and pregnancy outcome after blastocyst transfer remains unclear. Therefore, this study aimed to evaluate whether BMov after the first cell division is correlated with blastocyst formation rate and live birth rate after single vitrified-warmed blastocyst transfer (SVBT). METHODS: Nine hundred and sixty-six embryos cultured in the EmbryoScope+® time-lapse system were retrospectively analyzed. The BMov type was categorized into three groups; namely, bouncing, wobbling, and twist-and-crumble. The BMov duration (dBMov) between the first (t2) and second cell division (t3) was monitored, and the ratio of dBMov to the duration of the 2-cell stage was calculated [dBMov/(t3-t2)]. Developmental rates to the 4-cell, 8-cell, morula, blastocyst, and expanded blastocyst stages were assessed, as well as blastocyst morphological grade. The correlations between dBMov and clinical pregnancy, ongoing pregnancy, and live birth rates were evaluated. RESULTS: Increased dBMov/(t3-t2) was significantly correlated with decreased developmental rates to the 8-cell, morula, blastocyst, and expanded blastocyst stages, especially from the 4-cell stage to the morula stage. Analysis of different types of BMov revealed that embryos with bouncing movement exhibited significantly higher developmental rates to the 8-cell, morula, blastocyst, and expanded blastocyst stages compared with embryos with twist-and-crumble movement. The morphological quality of blastocyst-stage embryos with twist-and-crumble movement was significantly lower than that of embryos with bouncing and wobbling movements. The rates of clinical pregnancy, ongoing pregnancy, and live birth after SVBT were not correlated with BMov type or duration. CONCLUSIONS: Embryonic compaction and subsequent blastocyst formation are adversely affected by twist-and-crumble movement and prolonged movement after the first cell division. Our results indicate that the preimplantation developmental competence of human embryos could be predicted by assessing BMov after the first cell division on day 1.

Prolonged blastomere movement induced by the delay of pronuclear fading and first cell division adversely affects pregnancy outcomes after fresh embryo transfer on Day 2: a time-lapse study.

RESEARCH QUESTION: What is the incidence, origin and clinical significance of blastomere movement after the first cell division in the human embryo? DESIGN: A total of 1096 embryos, cultured in the EmbryoScope+ ® time-lapse system and subjected to a single fresh cleaved embryo transfer, were retrospectively analysed. Type and duration of blastomere movement (dBMov) between the first (t2) and second cell division (t3) was monitored, and the ratio of dBMov during the 2-cell stage [dBMov/(t3-t2)] was calculated. Morphological evaluation of embryos was performed by referring to the size of the blastomere and fragmentation after first division in addition to Veeck's criteria on Day 2. The correlation between dBMov and ongoing pregnancy was evaluated and the association of dBMov with patient and embryonic characteristics was determined. RESULTS: Both movement type and the value of dBMov/(t3-t2) were significantly associated with asymmetrical first division, fragment formation and morphological grade on Day 2. Multivariate logistic regression analysis revealed that a higher value of dBMov/(t3-t2) significantly correlated with a decreased ongoing pregnancy rate, even after adjustment for co-founders (odds ratio 0.399, P = 0.0419). The time intervals of pronuclear (PN) alignment and PN fading were significantly correlated with the dBMov/(t3-t2) value. CONCLUSIONS: Embryos with extended blastomere movement after the first cell division, which is associated with the delay of PN fading and first cell division, have a lower competence to initiate an ongoing pregnancy after fresh embryo transfer on Day 2. Thus, blastomere movement could be a useful predictive parameter for selecting embryos at the early cleavage stage.

Overnight ovarian tissue transportation for centralized cryobanking: a feasible option.

RESEARCH QUESTION: Is overnight transportation of ovarian tissue before cryopreservation in a centralized cryobank from the FertiPROTEKT network feasible? DESIGN: Data from 1810 women with cryopreserved ovarian tissue after overnight transportation from December 2000 to December 2017 were analysed with a focus on transportation, tissue activity parameters and pregnancy, and delivery rates after transplantation. RESULTS: A total of 92.4% of tissue samples arrived at ideal temperatures of 2-8°C, 0.4% were transported at temperatures lower than ideal and 6.4% were transported at temperatures that were too high, generally due to mishandling of the inlayed cool packs of the transportation boxes. In 62 women, 78 tissue transplantations were carried out. A subgroup of 30 women who underwent a single orthotopic transplantation with fulfilled criteria of a complete follow-up after transplantation until the end of study, a premature ovarian insufficiency after gonadotoxic therapy as well as the absence of pelvic radiation, was further analysed. In this group, transplantations into a peritoneal pocket accounted for 90%. Transplants were still active at 1 year and above after transplantation in 93.3%. Pregnancy and delivery rates were 46.7% and 43.3%, respectively, with one ongoing pregnancy at the end of the study. CONCLUSIONS: Overnight transportation for central cryobanking is a feasible concept that results in high reproducible success rates through standardized professional tissue freezing and storage.

Is there a correlation between follicle size and gene expression in cumulus cells and is gene expression an indicator of embryo development?

BACKGROUND: In an article published in 2017, we discussed the results of the first part of our study into the morphokinetic development of embryos in relation to follicle diameter and homogeneity of follicular development. Our findings showed that embryos coming from small follicles in heterogeneous cycles had significantly higher rates of arrest or failure to reach blastocyst than embryos coming from large follicles in homogenous cycles. The aim of this further study was to investigate the relationship between follicular size and gene expression of cumulus cells (CCs) and evaluate whether gene expression could be an indicator of embryo development. METHODS: This study was based on 2495 COCs from 184 patients. CC expressions of five genes (TNFAIP6, PTGS2, HAS2, PTX3 and GDF9) were studied by generalized linear mixed models (GLMMs) regarding follicular size. CC expressions were then separately analysed regarding patient-specific variables (age, BMI, AMH and follicular size) in relation to embryos reaching blastocyst (eRB) or top or good quality blastocysts (TQ + GQ) using GLMMs with logit link. RESULTS: Follicular size significantly correlated with the potential of an oocyte to develop into a blastocyst: oocytes developing from large follicles were more than twice as likely to develop into an eRB than oocytes from small follicles (p < 0.001). Gene expression of HAS2 and GDF9 correlated with blastocyst quality when separately evaluated with follicular size and the patient specific variables of age, BMI and AMH. However, no such correlation was found in other gene expressions studied. CONCLUSIONS: Our findings suggest that differences in the expression of genes studied could be related to follicular size rather than to embryo quality. Although gene expression of HAS2 and GDF9 correlated with blastocyst quality, the only variable correlating with eRB and TQ and GQ blastocysts for each of these five models was follicular size. TRIAL REGISTRATION: This prospective cohort study was registered at clinicaltrials.gov (NCT02230449).

Pregnancy rates of day 4 and day 5 embryos after culture in an integrated time-lapse incubator.

BACKGROUND: The aim of this study was to compare pregnancy rates in patients undergoing IVF/ICSI with embryo transfer after 4 and 5 days of culture in a closed incubation system with integrated time-lapse imaging. METHODS: Out of n = 2207 in vitro fertilization (IVF)/ intracytoplasmic sperm injection (ICSI) cycles performed between January 2011 and April 2016 at a tertiary referral university hospital, a total of n = 599 IVF/ICSI cycles with prolonged embryo culture in an integrated time-lapse system (EmbryoScope© (Vitrolife)) until day 4 or 5 were retrospectively analyzed with regard to embryo morphology and pregnancy rates. RESULTS: A transfer on day 5 compared to a transfer on day 4 did not result in higher implantation and clinical pregnancy rates (IR 29.4% on day 4 versus 33.0% on day 5, p = 0.310; CPR 45.2% on day 4 versus 45.7% on day 5, p = 1.0). The percentage of ideal embryos transferred on day 4 was comparable to the rate of ideal embryos transferred on day 5 (41.6% versus 44.1%, p = 0.508). However, on day 4 a significantly higher number of embryos was transferred (1.92 on day 4 versus 1.84 on day 5, p = 0.023), which did not result in higher rates of multiple pregnancies. CONCLUSIONS: Pregnancy rates in IVF/ICSI cycles with integrated time-lapse incubation and transfer on day 4 and 5 are comparable. This finding provides the clinician, IVF laboratory and patient with more flexibility. TRIAL REGISTRATION: This study was retrospectively registered by the local ethics committee of the University of Heidelberg on December 19, 2016 (registration number S-649/2016).

Time-lapse culture with morphokinetic embryo selection improves pregnancy and live birth chances and reduces early pregnancy loss: a meta-analysis.

Embryo evaluation and selection is fundamental in clinical IVF. Time-lapse follow-up of embryo development comprises undisturbed culture and the application of the visual information to support embryo evaluation. A meta-analysis of randomized controlled trials was carried out to study whether time-lapse monitoring with the prospective use of a morphokinetic algorithm for selection of embryos improves overall clinical outcome (pregnancy, early pregnancy loss, stillbirth and live birth rate) compared with embryo selection based on single time-point morphology in IVF cycles. The meta-analysis of five randomized controlled trials (n = 1637) showed that the application of time-lapse monitoring was associated with a significantly higher ongoing clinical pregnancy rate (51.0% versus 39.9%), with a pooled odds ratio of 1.542 (P < 0.001), significantly lower early pregnancy loss (15.3% versus 21.3%; OR: 0.662; P = 0.019) and a significantly increased live birth rate (44.2% versus 31.3%; OR 1.668; P = 0.009). Difference in stillbirth was not significant between groups (4.7% versus 2.4%). Quality of the evidence was moderate to low owing to inconsistencies across the studies. Selective application and variability were also limitations. Although time-lapse is shown to significantly improve overall clinical outcome, further high-quality evidence is needed before universal conclusions can be drawn.

The effect of follicle size and homogeneity of follicular development on the morphokinetics of human embryos.

PURPOSE: Our aim was to investigate follicular size (large, ≥17 mm and small, <17 mm) at the time of OPU and homogeneity of follicular development (homogenous development: follicles being present in a homogenous spread of all sizes; heterogeneous: a predominance of small and large follicles) by analysing the morphokinetics of embryo development. METHODS: In this prospective cohort study, 2526 COCs belonging to 187 patients were cultured to day 5. Embryos were evaluated morphokinetically. Four subgroups were defined: large follicles from heterogeneous cycles (LHet) and homogenous cycles (LHom) and small follicles from heterogeneous cycles (SHet) and homogenous cycles (SHom). RESULTS: Rates of fertilization, blastocyst formation and top and good quality blastocysts were found to be significantly higher in embryos from the LHom group (p < 0.001; p < 0.001; p < 0.001). Small follicles from both homogenous and heterogeneous cycles had significantly lower blastocyst formation and top and good quality blastocyst rates (p < 0.001; p < 0.001). Embryos from SHet had significantly more direct cleavages (p = 0.011). Time to reach blastocyst was shorter in SHom than LHet and LHom (p = 0.002; p = 0.027, respectively). However, once the blastocyst stage was achieved, implantation rates were not significantly different between subgroups, the highest rate being observed in the LHom group. Multivariable analysis revealed that homogeneity of follicular development and follicular size had a significant effect on blastocyst development and quality (p = 0.049; p < 0.001, respectively). CONCLUSION: Follicular dynamics, illustrated by follicular size and homogeneity of follicular development, influence early human embryo development. Patterns of follicular growth have an impact on embryo quality and viability which is reflected in morphokinetic variables.

The why, the how and the when of PGS 2.0: current practices and expert opinions of fertility specialists, molecular biologists, and embryologists.

STUDY QUESTION: We wanted to probe the opinions and current practices on preimplantation genetic screening (PGS), and more specifically on PGS in its newest form: PGS 2.0? STUDY FINDING: Consensus is lacking on which patient groups, if any at all, can benefit from PGS 2.0 and, a fortiori, whether all IVF patients should be offered PGS. WHAT IS KNOWN ALREADY: It is clear from all experts that PGS 2.0 can be defined as biopsy at the blastocyst stage followed by comprehensive chromosome screening and possibly combined with vitrification. Most agree that mosaicism is less of an issue at the blastocyst stage than at the cleavage stage but whether mosaicism is no issue at all at the blastocyst stage is currently called into question. STUDY DESIGN, SAMPLES/MATERIALS, METHODS: A questionnaire was developed on the three major aspects of PGS 2.0: the Why, with general questions such as PGS 2.0 indications; the How, specifically on genetic analysis methods; the When, on the ideal method and timing of embryo biopsy. Thirty-five colleagues have been selected to address these questions on the basis of their experience with PGS, and demonstrated by peer-reviewed publications, presentations at meetings and participation in the discussion. The first group of experts who were asked about 'The Why' comprised fertility experts, the second group of molecular biologists were asked about 'The How' and the third group of embryologists were asked about 'The When'. Furthermore, the geographical distribution of the experts has been taken into account. Thirty have filled in the questionnaire as well as actively participated in the redaction of the current paper. MAIN RESULTS AND THE ROLE OF CHANCE: The 30 participants were from Europe (Belgium, Germany, Greece, Italy, Netherlands, Spain, UK) and the USA. Array comparative genome hybridization is the most widely used method amongst the participants, but it is slowly being replaced by massive parallel sequencing. Most participants offering PGS 2.0 to their patients prefer blastocyst biopsy. The high efficiency of vitrification of blastocysts has added a layer of complexity to the discussion, and it is not clear whether PGS in combination with vitrification, PGS alone, or vitrification alone, followed by serial thawing and eSET will be the favoured approach. The opinions range from in favour of the introduction of PGS 2.0 for all IVF patients, over the proposal to use PGS as a tool to rank embryos according to their implantation potential, to scepticism towards PGS pending a positive outcome of robust, reliable and large-scale RCTs in distinct patient groups. LIMITATIONS, REASONS FOR CAUTION: Care was taken to obtain a wide spectrum of views from carefully chosen experts. However, not all invited experts agreed to participate, which explains a lack of geographical coverage in some areas, for example China. This paper is a collation of current practices and opinions, and it was outside the scope of this study to bring a scientific, once-and-for-all solution to the ongoing debate. WIDER IMPLICATIONS OF THE FINDINGS: This paper is unique in that it brings together opinions on PGS 2.0 from all different perspectives and gives an overview of currently applied technologies as well as potential future developments. It will be a useful reference for fertility specialists with an expertise outside reproductive genetics. LARGE SCALE DATA: none. STUDY FUNDING AND COMPETING INTERESTS: No specific funding was obtained to conduct this questionnaire.

Development of a generally applicable morphokinetic algorithm capable of predicting the implantation potential of embryos transferred on Day 3.

STUDY QUESTION: Can a generally applicable morphokinetic algorithm suitable for Day 3 transfers of time-lapse monitored embryos originating from different culture conditions and fertilization methods be developed for the purpose of supporting the embryologist's decision on which embryo to transfer back to the patient in assisted reproduction? SUMMARY ANSWER: The algorithm presented here can be used independently of culture conditions and fertilization method and provides predictive power not surpassed by other published algorithms for ranking embryos according to their blastocyst formation potential. WHAT IS KNOWN ALREADY: Generally applicable algorithms have so far been developed only for predicting blastocyst formation. A number of clinics have reported validated implantation prediction algorithms, which have been developed based on clinic-specific culture conditions and clinical environment. However, a generally applicable embryo evaluation algorithm based on actual implantation outcome has not yet been reported. STUDY DESIGN, SIZE, DURATION: Retrospective evaluation of data extracted from a database of known implantation data (KID) originating from 3275 embryos transferred on Day 3 conducted in 24 clinics between 2009 and 2014. The data represented different culture conditions (reduced and ambient oxygen with various culture medium strategies) and fertilization methods (IVF, ICSI). The capability to predict blastocyst formation was evaluated on an independent set of morphokinetic data from 11 218 embryos which had been cultured to Day 5. PARTICIPANTS/MATERIALS, SETTING, METHODS: The algorithm was developed by applying automated recursive partitioning to a large number of annotation types and derived equations, progressing to a five-fold cross-validation test of the complete data set and a validation test of different incubation conditions and fertilization methods. The results were expressed as receiver operating characteristics curves using the area under the curve (AUC) to establish the predictive strength of the algorithm. MAIN RESULTS AND THE ROLE OF CHANCE: By applying the here developed algorithm (KIDScore), which was based on six annotations (the number of pronuclei equals 2 at the 1-cell stage, time from insemination to pronuclei fading at the 1-cell stage, time from insemination to the 2-cell stage, time from insemination to the 3-cell stage, time from insemination to the 5-cell stage and time from insemination to the 8-cell stage) and ranking the embryos in five groups, the implantation potential of the embryos was predicted with an AUC of 0.650. On Day 3 the KIDScore algorithm was capable of predicting blastocyst development with an AUC of 0.745 and blastocyst quality with an AUC of 0.679. In a comparison of blastocyst prediction including six other published algorithms and KIDScore, only KIDScore and one more algorithm surpassed an algorithm constructed on conventional Alpha/ESHRE consensus timings in terms of predictive power. LIMITATIONS, REASONS FOR CAUTION: Some morphological assessments were not available and consequently three of the algorithms in the comparison were not used in full and may therefore have been put at a disadvantage. Algorithms based on implantation data from Day 3 embryo transfers require adjustments to be capable of predicting the implantation potential of Day 5 embryo transfers. The current study is restricted by its retrospective nature and absence of live birth information. Prospective Randomized Controlled Trials should be used in future studies to establish the value of time-lapse technology and morphokinetic evaluation. WIDER IMPLICATIONS OF THE FINDINGS: Algorithms applicable to different culture conditions can be developed if based on large data sets of heterogeneous origin. STUDY FUNDING/COMPETING INTERESTS: This study was funded by Vitrolife A/S, Denmark and Vitrolife AB, Sweden. B.M.P.'s company BMP Analytics is performing consultancy for Vitrolife A/S. M.B. is employed at Vitrolife A/S. M.M.'s company ilabcomm GmbH received honorarium for consultancy from Vitrolife AB. D.K.G. received research support from Vitrolife AB.

Extracellular vesicles in human follicular fluid do not promote coagulation.

Body fluids contain extracellular vesicles expressing tissue factor on their surface and serve as an additional trigger for coagulation. During the menstrual cycle ovarian tissue restoration is mandatory and it is unknown whether follicular fluid might provide procoagulant substances. Within an observational study, follicular fluid from women undergoing IVF/intracytoplasmic sperm injection (ICSI) was analysed by fluorescence-activated cell sorting (FACS), electron microscopy, resistive pulse sensing (RPS), nanoparticle-tracking analysis (NTA) and fibrin generation tests (FGT). The presence of extracellular vesicles, especially CD9-positive extracellular vesicles in follicular fluid, was proven. However, clotting tests revealed no procoagulant properties of the detected extracellular vesicles.

Use of both cumulus cells' transcriptomic markers and zona pellucida birefringence to select developmentally competent oocytes in human assisted reproductive technologies.

BACKGROUND: Selection of the best oocyte for subsequent steps of fertilization and embryo transfer was shown to be the crucial step in human infertility treatment procedure. Oocyte selection using morphological criteria mainly Zona pellucida (ZP) has been the gold standard method in assisted reproductive technologies (ART) clinics, but this selection approach has limitations in terms of accuracy, objectivity and constancy. Recent studies using OMICs-based approaches have allowed the identification of key molecular markers that quantitatively and non-invasively predict the oocyte quality for higher pregnancy rates and efficient infertility treatment. These biomarkers are a valuable reinforcement of the morphological selection criteria widely used in in vitro fertilization (IVF) clinics. In this context, this study was designed to investigate the relationship between transcriptomic predictors of oocyte quality found by our group and the conventional morphological parameters of oocyte quality mainly the ZP birefringence. RESULTS: Microarray data revealed that 48 and 27 differentially expressed candidate genes in cumulus cells (CCs) were respectively overexpressed and underexpressed in the ZGP (Zona Good Pregnant) versus ZBNP (Zona Bad Non Pregnant) groups. More than 70% of previously reported transcriptomic biomarkers of oocyte developmental competence were confirmed in this study. The analysis of possible association between ZP birefringence versus molecular markers approach showed an absence of correlation between them using the current set of markers. CONCLUSIONS: This study suggested a new integrative approach that matches morphological and molecular approaches used to select developmentally competent oocytes able to lead to successful pregnancy and the delivery of healthy baby. For each ZP birefringence score, oocytes displayed a particular CCs' gene expression pattern. However, no correlations were found between the 7 gene biomarkers of oocyte developmental potential and the ZP birefringence score. Further studies using larger lists of candidate markers are required to identify suitable genes that are highly correlated with the morphological criteria, and therefore able to reinforce the accuracy of oocyte selection and the effectiveness of infertility treatment.

Live birth after artificial oocyte activation using a ready-to-use ionophore: a prospective multicentre study.

Artificial oocyte activation has been proposed as a suitable means to overcome the problem of failed or impaired fertilization after intracytoplasmic sperm injection (ICSI). In a multicentre setting artificial oocyte activation was applied to 101 patients who were diagnosed with fertilization abnormalities (e.g. less than 50% fertilized oocytes) in a previous conventional ICSI cycle. Female gametes were activated for 15 min immediately after ICSI using a ready-to-use Ca(2+)-ionophore solution (A23187). Fertilization, pregnancy and live birth rates were compared with the preceding cycle without activation. The fertilization rate of 48% in the study cycles was significantly higher compared with the 25% in the control cycles (P < 0.001). Further splitting of the historical control group into failed (0%), low (1-30%) and moderate fertilization rate (31-50%) showed that all groups significantly benefitted (P < 0.001) in the ionophore cycle. Fewer patients had their embryo transfer cancelled compared with their previous treatments (1/101 versus 15/101). In total, 99% of the patients had an improved outcome with A23187 application resulting in a 28% live birth rate (35 babies). These data suggest that artificial oocyte activation using a ready-to-use compound is an efficient method.

Spontaneous antral follicle formation and metaphase II oocyte from a non-stimulated prepubertal ovarian tissue xenotransplant.

BACKGROUND: Current strategies in cancer treatment have markedly increased the rates of remission and survival for cancer patients, but are often associated with subsequent sterility. While there are various options available to an adult female depending on the patient's particular situation, the only realistic option for preserving fertility in prepubertal females is to cryopreserve ovarian tissue. This is the first report of a morphologically mature oocyte collected from non-stimulated prepubertal ovarian tissue xenotransplants. METHODS: Ovarian tissue from a 6 year old patient suffering from nephroblastoma was removed and cryopreserved for fertility preservation. The frozen-thawed ovarian tissue fragments were xenotransplanted to bilaterally oophorectomized severe combined immunodeficiency (SCID) mice to assess follicle development. RESULTS: Antral follicle formation occurred post-xenotransplantation in a single ovarian fragment without exogenous hormone stimulation. A morphologically maturing oocyte was harvested from these follicles. CONCLUSIONS: Prepubertal human ovarian follicles and oocytes can be matured after xenotransplantation even without exogenous hormone stimulation. These results indicate that tissue collected from prepubertal patients can support fertility in cancer survivors.

Natural cycle IVF: evaluation of 463 cycles and summary of the current literature.

PURPOSE: Natural cycle (NC) IVF/ICSI has proven to be an alternative to conventional IVF/ICSI cycles. METHODS: Within our retrospective, observational study (n = 159) infertile couples underwent (n = 463) cycles of NC-IVF/ICSI from May 2007 until December 2011. Oocyte pick-up was performed within a pure natural cycle excluding any hormonal stimulation except of hCG for ovulation induction. Oocytes were fertilized by IVF/ICSI and embryo transfer took place 2 or 3 days later. In addition, the current literature was analysed concerning pregnancy rates in NC-IVF/ICSI cycles. RESULTS: Oocyte pick-up was performed in n = 463 NC and was successful in n = 342 cases (IVF n = 135, ICSI n = 207). 203 oocytes were fertilized (IVF n = 87, ICSI n = 116, FR 59.4 %) and lead to 192 embryo transfers. Finally, 25 pregnancies were reached (PR 13.0 % per transfer) resulting in four biochemical pregnancies, 7 (33.3 %) miscarriages, one pregnancy of unknown outcome and 13 live births. Within the current literature (n = 27 studies), PR in NC-IVF/ICSI cycles varied between 10.2 and 50 %. CONCLUSIONS: Within our study, pregnancy rates in pure NC-IVF/ICSI remained below 15 %. Although this may be linked to unfavourable preconditions like patients' age >40 years, low ovarian reserve or long duration of infertility, further improvement is necessary to increase pregnancy rates.

Morphokinetics and embryo aneuploidy: has time come or not yet?

Morphokinetic analysis of early human embryos in combination with trophectoderm biopsy and chromosomal enumeration by array technology has been shown to identify embryos with single and/or multiple aneuploidies. In a time-lapse imaging study, aneuploid embryos showed a delayed initiation of blastocyst formation and also reached the full blastocyst stage later compared with euploid embryos. Based on these findings, a model for a risk factor classification for aneuploidy of human embryos has been established. However, time values that allow differentiation between different risk classes have to be considered carefully as timings that are prognostic for one clinic may not apply directly to another clinic. Thus, risk models may need to be verified in specific IVF settings. Further studies are needed to verify that time-lapse imaging does allow subselection of embryos with a high aneuploidy risk and thus does hold the chance to restrict invasive biopsy procedures to those embryos where there is uncertainty regarding the chromosomal status.

New approaches to embryo selection.

Embryo selection has been an important topic since the introduction of assisted reproduction, with embryo morphology being the most obvious criterion. Although morphology serves as indicator for overall IVF laboratory quality, its statistical assessment limits the possibility to identify the most implantation-competent embryos. In order to reach a direct picture of the developing embryo, invasive procedures such as preimplantation genetic screening or transcriptome and proteome analysis of biopsied embryonic tissue were initially prioritized and are still under investigation. More recently, focus has shifted towards noninvasive techniques that maintain the integrity of the embryo. Metabolomic profiling of culture medium from growing embryos attracted much research. Although successful in a pilot study, that approach failed in a randomized controlled trial. Other metabolomics studies are on their way but not yet available for routine clinical use. The most promising strategy at present is the combined evaluation of morphology and developmental kinetics using time-lapse imaging. This has brought new insights into certain characteristics that enable deselection of embryos at an early stage of development and to identify others with high potential for successful implantation. However, there is still considerable room for improvement. Further strategies will most likely involve the combination of several different approaches.