Fertility Preservation in the Era of Immuno-Oncology: Lights and Shadows

In recent years, immuno-oncology has revolutionized the cancer treatment field by harnessing the immune system's power to counteract cancer cells. While this innovative approach holds great promise for improving cancer outcomes, it also raises important considerations related to fertility and reproductive toxicity. In fact, most young females receiving gonadotoxic anti-cancer treatments undergo iatrogenic ovarian exhaustion, resulting in a permanent illness that precludes the vocation of motherhood as a natural female sexual identity. Although commonly used, oocyte cryopreservation for future in vitro fertilization and even ovarian cortex transplantation are considered unsafe procedures in cancer patients due to their oncogenic risks; whereas, ovarian stem cells might support neo-oogenesis, providing a novel stemness model of regenerative medicine for future fertility preservation programs in oncology. Recent scientific evidence has postulated that immune checkpoint inhibitors (ICIs) might in some way reduce fertility by inducing either primary or secondary hypogonadism, whose incidence and mechanisms are not yet known. Therefore, considering the lack of data, it is currently not possible to define the most suitable FP procedure for young patients who are candidates for ICIs. In this report, we will investigate the few available data concerning the molecular regulation of ICI therapy and their resulting gonadal toxicity, to hypothesize the most suitable fertility preservation strategy for patients receiving these drugs.

A novel machine-learning framework based on early embryo morphokinetics identifies a feature signature associated with blastocyst development

BACKGROUND

Artificial Intelligence entails the application of computer algorithms to the huge and heterogeneous amount of morphodynamic data produced by Time-Lapse Technology. In this context, Machine Learning (ML) methods were developed in order to assist embryologists with automatized and objective predictive models able to standardize human embryo assessment. In this study, we aimed at developing a novel ML-based strategy to identify relevant patterns associated with the prediction of blastocyst development stage on day 5.

METHODS

We retrospectively analysed the morphokinetics of 575 embryos obtained from 80 women who underwent IVF at our Unit. Embryo morphokinetics was registered using the Geri plus® time-lapse system. Overall, 30 clinical, morphological and morphokinetic variables related to women and embryos were recorded and combined. Some embryos reached the expanded blastocyst stage on day 5 (BL Group, n = 210), some others did not (nBL Group, n = 365).

RESULTS

The novel EmbryoMLSelection framework was developed following four-steps: Feature Selection, Rules Extraction, Rules Selection and Rules Evaluation. Six rules composed by a combination of 8 variables were finally selected, and provided a predictive power described by an AUC of 0.84 and an accuracy of 81%.

CONCLUSIONS

We provided herein a new feature-signature able to identify with an high performance embryos with the best developmental competence to reach the expanded blastocyst stage on day 5. Clear and clinically relevant cut-offs were identified for each considered variable, providing an objective tool for early embryo developmental assessment.

Association between oocyte donors' or recipients' body mass index and clinical outcomes after first single blastocyst transfers-the uterus is the most affected

OBJECTIVE

To assess whether high body mass index (BMI) in either oocyte donors or recipients is associated with poorer outcomes after the first single blastocyst transfer.

DESIGN

Retrospective study including 1,394 first blastocyst single embryo transfers (SETs) conducted by 1,394 recipients during oocyte donation cycles with the gametes retrieved from 1,394 women (January 2019-July 2021). Four BMI clusters were defined for both donors and recipients (underweight: <18.5 kg; normal weight: 18.5-24.9 kg; overweight: 25-29.9 kg; and obese: ≥30 kg).

SETTING

Network of private IVF centers.

PATIENTS

A total of 1,394 recipients aged 42.4 ± 4.0 and with a BMI of 23.2 ± 3.8 kg/m2, and 1,394 donors aged 26.1 ± 4.2 and with a BMI of 21.9 ± 2.5 kg/m2.

INTERVENTION

All oocytes were vitrified at 2 egg banks and warmed at 8 in vitro fertilization clinics that were part of the same network. Intracytoplasmic sperm injection, blastocyst culture, and either fresh or vitrified-warmed SETs were conducted. Putative confounders were investigated, and the data were adjusted through regression analyses.

MAIN OUTCOME MEASURES

The primary outcome was the live birth rate (LBR) per SET according to donors' and/or recipients' BMI. The main secondary outcome was the miscarriage rate (<22 gestational weeks) per clinical pregnancy.

RESULTS

The LBR per blastocyst SET showed no significant association with donors' BMI. Regarding recipients' BMI, instead, the multivariate odds ratio was significant in obese vs. normal-weight recipients (0.58, 95% confidence interval, 0.37-0.91). The miscarriage rate per clinical pregnancy was also significantly associated with recipients' obesity, with a multivariate odds ratio of 2.31 (95% confidence interval, 1.18-4.51) vs. normal-weight patients. A generalized additive model method was used to represent the relationship between predicted LBR or miscarriage rates and donors' or recipients' BMI; it pictured a scenario where the former outcome moderately but continuously decreases with increasing recipients' BMI to then sharply decline in the BMI range of 25-35 kg/m2. The miscarriage rate, instead, increases almost linearly with respect to both donors' and recipients' increasing BMI.

CONCLUSION

Obesity mostly affects the uterus, especially because of higher miscarriage rates. Yet, poorer outcomes can be appreciated already with a BMI of 25 kg/m2 in both oocyte donors and recipients. Finer markers of nutritional homeostasis are therefore desirable; recipients should be counseled about poorer expected outcomes in cases of overweight and obesity; and oocyte banks should avoid assigning oocytes from overweight donors to overweight and obese recipients.

Innovative Strategies for Fertility Preservation in Female Cancer Survivors: New Hope from Artificial Ovary Construction and Stem Cell-Derived Neo-Folliculogenesis

Recent advances in anticancer treatment have significantly improved the survival rate of young females; unfortunately, in about one third of cancer survivors the risk of ovarian insufficiency and infertility is still quite relevant. As the possibility of becoming a mother after recovery from a juvenile cancer is an important part of the quality of life, several procedures to preserve fertility have been developed: ovarian surgical transposition, induction of ovarian quiescence by gonadotropin-releasing hormone agonists (GnRH-a) treatment, and oocyte and/or ovarian cortical tissue cryopreservation. Ovarian tissue cryostorage and allografting is a valuable technique that applies even to prepubertal girls; however, some patients cannot benefit from it due to the high risk of reintroducing cancer cells during allograft in cases of ovary-metastasizing neoplasias, such as leukemias or NH lymphomas. Innovative techniques are now under investigation, as in the construction of an artificial ovary made of isolated follicles inserted into an artificial matrix scaffold, and the use of stem cells, including ovarian stem cells (OSCs), to obtain neo-folliculogenesis and the development of fertilizable oocytes from the exhausted ovarian tissue. This review synthesizes and discusses these innovative techniques, which potentially represent interesting strategies in oncofertility programs and a new hope for young female cancer survivors.

Discard or not discard, that is the question: an international survey across 117 embryologists on the clinical management of borderline quality blastocysts

STUDY QUESTION

Do embryologists from different European countries agree on embryo disposition decisions ('use' or 'discard') about Day 7 (>144 h post-insemination) and/or low-quality blastocysts (LQB;

SUMMARY ANSWER

The prevalence of 'discard' answers was 38.7%; nevertheless, embryologists' agreement was overall just fair (Fleiss-k = 0.26).

WHAT IS KNOWN ALREADY

The utilization of LQBs and adoption of culture beyond 144 h post-insemination is increasing worldwide. Although morphology and morphokinetics are associated with embryo developmental competence, previous studies demonstrated significant interobserver variability among embryologists regarding embryo quality assessment and disposition decisions for borderline quality blastocysts.

STUDY DESIGN, SIZE, DURATION

An anonymous survey was run in a large network of IVF centers. A total of 117 embryologists from 6 European countries and 29 IVF centers filled in the survey. Randomly selected anonymous time-lapse videos of 50 Day 7 and/or LQB whole embryo preimplantation development were assessed by the embryologists. The key information on patients/cycles was provided along with each video. All cycles entailed preimplantation genetic testing for aneuploidies. Each embryologist specified whether he/she would have discarded or used ('transfer-fresh'/'cryopreserve'/'biopsy') any embryo. Inter-rater agreement was measured with Fleiss-k.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Examiners were asked about their years of experience, center location, average number of cycles and average maternal age, number of colleagues, and use of time-lapse incubators at their centers. All participants were blinded to artificial intelligence (AI) scores generated by two commercially available software packages, chromosomal diagnosis (all blastocysts were tested for aneuploidies), and clinical outcomes after vitrified-warmed euploid single blastocyst transfer. These data were known only by one embryologist not involved in the survey.

MAIN RESULTS AND THE ROLE OF CHANCE

Participants were Italian (40%, N = 47), Spanish (24%, N = 28), Portuguese (5%, N = 6), Czech (5%, N = 6), Swedish (23%, N = 27), and Icelandic (3%, N = 3). In total, 2263 (38.7%) 'discard' and 3587 (61.3%) 'use' decisions were recorded. Czech, Portuguese, and Italian embryologists expressed lower 'discard' decision rates (mean ± SD 17 ± 7%, range 8-24%; 23 ± 14% range 4-46%; and 27 ± 18% range 2-72%, respectively), while Spanish gave intermediate (37 ± 16% range 4-66%) and Nordic gave higher (67 ± 11% range 40-90%) rates. The prevalence of 'discard' answers was 38.7% out of 5850 choices (mean per embryologist: 39 ± 23% range 2-90%). Only embryologists' country and IVF group were associated with this rate. Overall agreement among embryologists was fair (Fleiss-k = 0.26). The prevalence of 'discard' responses per embryo was 37 ± 24% (range 2-87%). Only the number of sibling blastocysts influenced this rate (i.e. the larger the cohort, the higher the inclination to 'discard'). No difference was shown for the two scores between euploid and aneuploid borderline quality blastocysts, while the embryologists were, by chance, more prone to 'discard' the latter (28.3 ± 21% range 9-71% versus 41.6 ± 24.8% range 2-87%, respectively).

LIMITATIONS, REASONS FOR CAUTION

The survey included only private IVF clinics located in Europe. Moreover, a key variable is missing, namely patients' access to care. Indeed, all embryologists involved in the survey were part of the same network of private IVF clinics, while the embryo disposition decisions might be different in a public setting.

WIDER IMPLICATIONS OF THE FINDINGS

Decision-making by European embryologists regarding Day 7 embryos or LQBs is inconsistent with putative clinical consequences, especially in patients with low prognosis. Although the embryologists could make decisions independent from their local regulations, their mindset and clinical background influenced their choices. In the future, AI tools should be trained to assess borderline quality embryos and empowered with cost-effectiveness information to support embryologists' decisions with more objective assessments.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was obtained for this study. The authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

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Key Words

• Day 7 blastocysts
• artificial intelligence
• decision-making
• embryo competence
• low-quality blastocysts

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MESH Headings

• Female
• Humans
• Aneuploidy
• Artificial Intelligence
• Blastocyst/physiology
• Embryo Transfer/methods
• Maternal Age
• Retrospective Studies
• Male

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Affiliation(s)

Viviana Chiappetta IVIRMA Global Research Alliance, GENERA, Clinica Valle Giulia, Rome, Italy
Federica Innocenti IVIRMA Global Research Alliance, GENERA, Clinica Valle Giulia, Rome, Italy
Giovanni Coticchio IVIRMA Global Research Alliance, 9.baby, Bologna, Italy
Aisling Ahlström IVIRMA Global Research Alliance, LIVIO, Göteborg, Sweden
Laura Albricci IVIRMA Global Research Alliance, GENERA, Clinica Valle Giulia, Rome, Italy
Vicente Badajoz IVIRMA Global Research Alliance, GINEFIV, Madrid, Spain
Maria Hebles IVIRMA Global Research Alliance, GINEMED, Sevilla, Spain
Miguel Gallardo IVIRMA Global Research Alliance, GINEMED, Lisbon, Portugal
Francesca Benini IVIRMA Global Research Alliance, DEMETRA, Florence, Italy
Stefano Canosa IVIRMA Global Research Alliance, LIVET, Turin, Italy
Jiří Kumpošt IVIRMA Global Research Alliance, FERTICARE, Prague, Czech Republic
Katarina Milton IVIRMA Global Research Alliance, CARL VON LINNÈ KLINIKEN, Uppsala, Sweden
Diletta Montanino Oliva Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
Roberta Maggiulli IVIRMA Global Research Alliance, GENERA, Clinica Valle Giulia, Rome, Italy
Laura Rienzi IVIRMA Global Research Alliance, GENERA, Clinica Valle Giulia, Rome, Italy Department of Biomolecular Sciences, University of Urbino "Carlo Bo", Urbino, Italy
Danilo Cimadomo IVIRMA Global Research Alliance, GENERA, Clinica Valle Giulia, Rome, Italy

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Opening the black box: why do euploid blastocysts fail to implant? A systematic review and meta-analysis

BACKGROUND

A normal chromosomal constitution defined through PGT-A assessing all chromosomes on trophectoderm (TE) biopsies represents the strongest predictor of embryo implantation. Yet, its positive predictive value is not higher than 50-60%. This gap of knowledge on the causes of euploid blastocysts' reproductive failure is known as 'the black box of implantation'.

OBJECTIVE AND RATIONALE

Several embryonic, maternal, paternal, clinical, and IVF laboratory features were scrutinized for their putative association with reproductive success or implantation failure of euploid blastocysts.

SEARCH METHODS

A systematic bibliographical search was conducted without temporal limits up to August 2021. The keywords were '(blastocyst OR day5 embryo OR day6 embryo OR day7 embryo) AND (euploid OR chromosomally normal OR preimplantation genetic testing) AND (implantation OR implantation failure OR miscarriage OR abortion OR live birth OR biochemical pregnancy OR recurrent implantation failure)'. Overall, 1608 items were identified and screened. We included all prospective or retrospective clinical studies and randomized-controlled-trials (RCTs) that assessed any feature associated with live-birth rates (LBR) and/or miscarriage rates (MR) among non-mosaic euploid blastocyst transfer after TE biopsy and PGT-A. In total, 41 reviews and 372 papers were selected, clustered according to a common focus, and thoroughly reviewed. The PRISMA guideline was followed, the PICO model was adopted, and ROBINS-I and ROB 2.0 scoring were used to assess putative bias. Bias across studies regarding the LBR was also assessed using visual inspection of funnel plots and the trim and fill method. Categorical data were combined with a pooled-OR. The random-effect model was used to conduct the meta-analysis. Between-study heterogeneity was addressed using I2. Whenever not suitable for the meta-analysis, the included studies were simply described for their results. The study protocol was registered at http://www.crd.york.ac.uk/PROSPERO/ (registration number CRD42021275329).

OUTCOMES

We included 372 original papers (335 retrospective studies, 30 prospective studies and 7 RCTs) and 41 reviews. However, most of the studies were retrospective, or characterized by small sample sizes, thus prone to bias, which reduces the quality of the evidence to low or very low. Reduced inner cell mass (7 studies, OR: 0.37, 95% CI: 0.27-0.52, I2 = 53%), or TE quality (9 studies, OR: 0.53, 95% CI: 0.43-0.67, I2 = 70%), overall blastocyst quality worse than Gardner's BB-grade (8 studies, OR: 0.40, 95% CI: 0.24-0.67, I2 = 83%), developmental delay (18 studies, OR: 0.56, 95% CI: 0.49-0.63, I2 = 47%), and (by qualitative analysis) some morphodynamic abnormalities pinpointed through time-lapse microscopy (abnormal cleavage patterns, spontaneous blastocyst collapse, longer time of morula formation I, time of blastulation (tB), and duration of blastulation) were all associated with poorer reproductive outcomes. Slightly lower LBR, even in the context of PGT-A, was reported among women ≥38 years (7 studies, OR: 0.87, 95% CI: 0.75-1.00, I2 = 31%), while obesity was associated with both lower LBR (2 studies, OR: 0.66, 95% CI: 0.55-0.79, I2 = 0%) and higher MR (2 studies, OR: 1.8, 95% CI: 1.08-2.99, I2 = 52%). The experience of previous repeated implantation failures (RIF) was also associated with lower LBR (3 studies, OR: 0.72, 95% CI: 0.55-0.93, I2 = 0%). By qualitative analysis, among hormonal assessments, only abnormal progesterone levels prior to transfer were associated with LBR and MR after PGT-A. Among the clinical protocols used, vitrified-warmed embryo transfer was more effective than fresh transfer (2 studies, OR: 1.56, 95% CI: 1.05-2.33, I2 = 23%) after PGT-A. Lastly, multiple vitrification-warming cycles (2 studies, OR: 0.41, 95% CI: 0.22-0.77, I2 = 50%) or (by qualitative analysis) a high number of cells biopsied may slightly reduce the LBR, while simultaneous zona-pellucida opening and TE biopsy allowed better results than the Day 3 hatching-based protocol (3 studies, OR: 1.41, 95% CI: 1.18-1.69, I2 = 0%).

WIDER IMPLICATIONS

Embryo selection aims at shortening the time-to-pregnancy, while minimizing the reproductive risks. Knowing which features are associated with the reproductive competence of euploid blastocysts is therefore critical to define, implement, and validate safer and more efficient clinical workflows. Future research should be directed towards: (i) systematic investigations of the mechanisms involved in reproductive aging beyond de novo chromosomal abnormalities, and how lifestyle and nutrition may accelerate or exacerbate their consequences; (ii) improved evaluation of the uterine and blastocyst-endometrial dialogue, both of which represent black boxes themselves; (iii) standardization/automation of embryo assessment and IVF protocols; (iv) additional invasive or preferably non-invasive tools for embryo selection. Only by filling these gaps we may finally crack the riddle behind 'the black box of implantation'.

Cryostorage management of reproductive cells and tissues in ART: status, needs, opportunities and potential new challenges

Among the wide range of procedures performed by clinical embryologists, the cryopreservation of reproductive cells and tissues represents a fundamental task in the daily routine. Indeed, cryopreservation procedures can be considered a subspecialty of medically assisted reproductive technology (ART), having the same relevance as sperm injection or embryo biopsy for preimplantation genetic testing. However, although a great deal of care has been devoted to optimizing cryopreservation protocols, the same energy has only recently been spent on developing and implementing strategies for the safe and reliable storage and transport of reproductive specimens. Herein, we have summarized the content of the available guidelines, the risks, the needs and the future perspectives regarding the management of cryopreservation biorepositories used in ART.

Reproductive and Obstetric Outcomes Following a Natural Cycle vs. Artificial Endometrial Preparation for Frozen-Thawed Embryo Transfer: A Retrospective Cohort Study

Background: The proportion of frozen embryo transfer cycles has consistently grown in recent decades. Some adverse obstetric outcomes after frozen embryo transfer could possibly be explained by different approaches in endometrial preparation. The aim of the present study was to investigate reproductive and obstetric outcomes after frozen embryo transfer, comparing different endometrial preparation strategies. Methods: This retrospective study included 317 frozen embryo transfer cycles, of which 239 had a natural or modified natural cycle and 78 underwent artificial endometrial preparation. After excluding late abortion and twin pregnancies, the outcomes of 103 pregnancies were analyzed, 75 of which were achieved after a natural cycle/modified natural cycle, and 28 were achieved after an artificial cycle. Results: The overall clinical pregnancy rate/embryo transfer was 39.7%, the miscarriage rate was 10.1%, and the live birth rate/embryo transfer was 32.8%, without significant differences in reproductive outcomes between natural/modified cycle and artificial cycle groups. The risks of pregnancy-induced hypertension and abnormal placental insertion were significantly increased in pregnancies achieved after the artificial preparation of the endometrium (p = 0.0327 and =0.0191, respectively). Conclusions: Our study encourages the use of a natural cycle or modified natural cycle for endometrial preparation for frozen embryo transfer in order to ensure the presence of a corpus luteum able to orchestrate maternal adaptation to pregnancy.

P-189 Association between iDAScore v1.0, senior embryologists’ grading and euploidy in 546 blastocysts obtained during 189 PGT-A cycles

Study question

Is (intelligent data analysis) iDAScore v1.0 associated with euploidy at the blastocyst stage?

Summary answer

iDAScore v1.0 significantly correlated with euploidy (maternal age-adjusted OR:1.3 and AUC:0.72). Euploid blastocysts were ranked highest in ca.70% of the cohorts with both diagnoses.

What is known already

With machine learning and artificial intelligence (AI) implementation in IVF, several studies have been published mostly aimed at providing standardized and reproducible tools for gamete/embryo assessment and selection. Several of the proposed models might not be generally applicable due to their development on only a single center, small sample size and poor representation of the numerous clinical scenarios. Furthermore, the evidence has been rarely confirmed prospectively and/or in multicenter studies. Lately, the EmbryoScope+ has incorporated the iDAScore v1.0. This algorithm scores the chance of embryo implantation based on the video of blastocyst development and with no need for timing annotations.

Study design, size, duration

Interim analysis of a prospective study. Between April-December 2021, 189 preimplantation-genetic-testing (PGT) cycles (maternal age:38.4±4yr) with ≥1 blastocyst (N = 546 blastocysts, mean±SD:2.9±1.8, range:1-13) were included. We aimed at blindly analyzing the correlation between iDAScore v1.0 and (i) blastocyst quality estimated by senior embryologists, (ii) day of blastocyst full-expansion, (iii) chromosomal constitution diagnosed by NGS on a trophectoderm biopsy, (iv) the blastocyst to prioritize for transfer within cohorts with ≥2 blastocysts.

Participants/materials, setting, methods

Undisturbed culture was conducted in the EmbryoScope+. Assisted hatching was not performed and only fully-expanded blastocysts were biopsied. Morphology was assessed by 2 senior embryologists based on Gardner criteria. Average iDAScores were reported for the following groups: (i)excellent (AA)/good (AB,BA)/average (BB,AC,CA)/poor-quality (CC,BC,CB) blastocysts, (ii)day5/6/7 blastocysts, (iii)euploid/aneuploid/complex aneuploid blastocysts. Lastly, we reported how often the highest iDAScore corresponded to the highest ranked morphology (N = 143 cycles with ≥2 blastocysts) and/or euploid blastocysts (N = 79 cycles with both diagnoses).

Main results and the role of chance

In the study period, 546 blastocysts (iDAScore: 6.9±2.0, 2-9.7) were biopsied. The iDAScore was significantly different (Kruskal-Wallis&lt;0.01) across blastocysts graded excellent (N = 256,46.9%; 8.1±1.3, 2.5-9.7), good (N = 97,17.7%; 6.9±1.6, 2.3-9.5), average (N = 75,13.9%; 5.8±1.4, 2.9-8.7) and poor (N = 118,21.5%; 4.8±1.6, 2-8.8). A significant difference (Kruskal-Wallis&lt;0.01) was also found for the day of full-expansion (day5: N = 184,33.9%, 8.8±0.8, 4.3-9.7; day6: N = 324,59.1%, 6.0±1.6, 2.2-9.1; day7: N = 38,6.9%, 4.6±1.6, 2-7.8). Euploid blastocysts (N = 178,32.6%) had a significantly higher (Kruskal-Wallis&lt;0.01) iDAScore (7.5±1.7, 2.4-9.6) than both simple (N = 209,38.3%, 6.7±2.1, 2.1-9.7) and complex aneuploid blastocysts (N = 159,29.1%, 6.3±2.0, 2-9.4). The logistic regression adjusted for maternal age highlighted a multivariate-OR 1.3, 95%CI 1.18-1.45, adjusted-p&lt;0.01 for the association between iDAScore v1.0 and euploidy. The Receiver-Operating-Characteristic (ROC) curves outlined similar performance in predicting euploidy among the models encompassing iDAScore v1.0 adjusted for maternal age (AUC: 0.72, 95%CI 0.67-0.76, p &lt; 0.01) or blastocyst quality (defined by senior embryologists) plus day of biopsy also adjusted for maternal age (AUC: 0.73, 95%CI 0.69-0.78, p &lt; 0.01). iDAScore v1.0 and embryologists ranked the same blastocyst highest in 123 of 143 cycles with ≥2 blastocysts (86%). The highest ranked blastocyst according to iDAScore was a euploid blastocyst in 54 of the 79 cycles (68%) containing both euploid and aneuploid blastocysts.

Limitations, reasons for caution

The main purpose of iDAScore v1.0, for which the algorithm was trained, is implantation prediction of untested blastocysts. Thus, once the sample size of this blinded prospective study will be large enough, we will also examine the association between iDAScore v1.0 and the implantation of euploid blastocysts.

Wider implications of the findings

The similar predictivity on euploidy reported between subjective senior embryologists’ grading and objective AI-powered iDAscores is promising in view of IVF automation and standardization. This is especially relevant since iDAScore v1.0 has not been trained yet to specifically predict euploidy, and its future versions could be fine-tuned accordingly.

Trial registration number

Not Applicable

P-773 Assessment of the putative impact of culture strategies, oocyte/embryo manipulations, and operators: a retrospective analysis of 3705 blastocyst culture cycles and 2604 single blastocyst transfers

Study question

Do the culture strategies, oocyte/embryo manipulations, and operators impact blastulation-rates per cohort of metaphase-II oocytes (BR per MII-oocytes) and/or live-birth-rates per single-embryo-transfer (LBR per SET)?

Summary answer

Undisturbed culture improved the BR per MII-oocytes, while culture drop volumes ≥80ml in the well-of-the-well system were associated with increased LBR per untested/euploid blastocyst SET.

What is known already

IVF lab performance is critical to achieve success in IVF. Yet, while a consensus exists on the main key-performance-indicators (KPIs), namely BR and LBR, and their inherent benchmark values, the strategies to fulfil them are still poorly standardized. The plasticity of human embryos along with the disparities in the patient populations might mask even largely different outcomes across clinics. Therefore, clear guidelines shall outline which procedures to standardize and carefully monitor in IVF laboratories. Here we investigated different embryo culture strategies, manipulations, and operators for their effect on BR and LBR per SET, adjusting the results for all main confounders.

Study design, size, duration

Retrospective analysis of 3705 cycles with ≥1 MII-oocyte and 2604 SETs (January2019-March2021). BR per MII-oocytes and LBR per SET were the main outcomes. Embryo-twinning was also assessed. The putative impact of culture strategies, manipulations, and operators’ expertise (0-5yr,6-11yr or &gt; 12yr) was determined via regression analyses adjusted for possible confounders (autologous/donated oocytes, age, primary/secondary infertility and duration, sperm factor; for SET: also endometrial preparation, age at transfer, number of consecutive transfer, untested/euploid blastocyst, quality, and day).

Participants/materials, setting, methods

In donation cycles, only vitrified oocytes were used. In Preimplantation-Genetic-Testing (PGT) cycles, no assisted-hatching was performed and only euploid non-mosaic vitrified-warmed blastocysts were transferred. The culture strategies assessed were undisturbed (Embryoscope, Geri and Embryoscope-plus)/disturbed (KSystems), volume and approach (drops ≤30ml with single-culture or ≥ 80ml with well-of-the-well approaches), humidified/non-humidified atmosphere and media refreshed/not-refreshed. The manipulations assessed were oocyte/blastocyst vitrification (performed/not-performed), oocyte retrieval and denudation performed with oil overlay (yes/not), laser-assisted artificial-shrinkage (performed/not-performed), trophectoderm biopsy (performed/not-performed).

Main results and the role of chance

The only confounders on BR per MII-oocytes (overall:39.1±26.6%) were sperm factor and oocyte age. The linear regressions showed benefits for humidified atmosphere (unstandardized B-coefficient:+2.9%, p = 0.01), manipulations with oil overlay (+3.9%, p = 0.03) and drops≥80ml with a well-of-the-well approach (+4.3%, p &lt; 0.01). However, only the positive effect of undisturbed incubators was significant when adjusting for confounders [41.7±27.8% (N = 1440 cycles) versus 37.5±25.7% in a disturbed incubator (N = 2265 cycles); unstandardized B-coefficient:+5.6%, 95%CI +3.9% to + 7.3%, standardized beta-coefficient:-0.103,p&lt;0.01].

The main confounders on LBR per SET (overall: N = 1044/2604, 40.1%) were oocyte age, number of consecutive transfer, blastocyst chromosomal status (untested/euploid), quality and day. The univariate logistic regressions showed a benefit for undisturbed incubators (OR:1.3, 95%CI 1.1-1.5, p &lt; 0.01), humidified atmosphere (OR:1.4, 95%CI 1.1-1.7, p &lt; 0.01) and media refresh (OR:1.3, 95% 1.01-1.8, p = 0.05). However, only the use of drops ≥80ml with a well-of-the-well approach rather than drops ≤30ml with a single-culture approach involved an improvement when adjusting for confounders (untested SETs: N = 71/171, 41.5% versus N = 434/1284, 33.8%; euploid SETs: N = 170/316, 53.8% versus N = 369/833, 44.3%; multivariate-OR:1.33, 95%CI 1.12-1.58, adjusted p-value&lt;0.01). This result was confirmed in a sub-analysis across only first patients’ SETs.

Lastly, no feature under investigation was associated with embryo-twinning (overall: N = 23/1243, 1.9% and N = 14/1044, 1.3% per pregnancy and delivery, respectively).

Limitations, reasons for caution

Retrospective single center study. Only ICSI cycles and continuous culture media were assessed. Cleavage stage SETs were excluded. All operators had at least 3yr of experience. Perinatal and gestational outcomes were not evaluated.

Wider implications of the findings

Real-life data adjusted for confounders may unveil fluctuations in critical KPIs mainly imputable to culture strategies. An impact seldom derives from oocyte/embryo manipulations if experienced operators adopt validated protocols. An accurate interpretation of these evidence shall lead to properly designed studies with problem-solving/progress-building purposes, and guidelines to standardize culture practices.

Trial registration number

Not applicable

P-442 A new option to thaw slow-frozen human ovarian tissue in cancer patients: efficacy and safety of the combination of different cryopreservation kits

Study question

Is follicular viability of slow-frozen human ovarian tissue preserved if rapid thawing is performed using a solution containing extracellular cryoprotectant only?

Summary answer

Follicular viability is preserved even using thawing solutions containing extracellular cryoprotectant only, combining kits with different composition.

What is known already

Ovarian tissue cryopreservation is an alternative option to oocytes or embryos for fertility preservation in cancer patients facing gonadotoxic treatments. To date, each brand producing kits approved for the slow-freezing of human ovarian tissue recommends the use of its own thawing kit. However, a potential single protocol based on the use of any extracellular cryoprotectant has already been proposed for human oocytes and embryos. The current study aims at finding alternative options to thaw cryopreserved human ovarian tissue when the original kit was withdrawn from the market and only one CE-marked kit was available, even with different composition in cryoprotectants.

Study design, size, duration

Ovarian tissue cryopreservation of ten cancer patients (18.3 ± 7.6 years) undergoing fertility preservation between 2001 and 2012 was performed following a slow-freezing protocol with 1.5M 1,2 PROH and 0.5M Sucrose. Once deceased, for each patient, cortical fragments were prospectively thawed and equally allocated into two groups: i) fragments thawed using 0.5-1M 1,2 PROH and 0.3M Sucrose (PROH+S Group, n = 73); ii) fragments thawed following an adjusted protocol with 0.5M Sucrose only (S Group, n = 73).

Participants/materials, setting, methods

Post thawing follicular density/mm2, integrity (%) and the presence of interstitial oedema were assessed by histological and ultrastructural analysis performed after formalin fixation and haematoxylin/eosin staining. Follicular viability was evaluated by the expression of markers of proliferation (Ki67) and of vascularization (CD31) by immunohistochemistry after a 24h culture in Iscove’s modified Dulbecco’s medium at 37 °C and 6% CO2. A paired comparison was performed referring to the fresh tissue of the same patient as control.

Main results and the role of chance

The histological evaluation performed after thawing revealed that follicles were predominantly primordial (91%), with no follicles larger than the proliferating primary stage. A significant reduction of follicular density per mm2 was observed in both study groups (14.2 ± 12.0 vs. 15.1 ± 14.0 for PROH+S and S Group, respectively; p = 0.4) compared to the fresh tissue (27.2 ± 31.6; p = 0.04) as well as a remarkable decreased of the proportion of intact follicles (39.3 ± 17.1 vs. 25.5 ± 9.8; p = 0.2) compared to the fresh tissue (98.1 ± 1.4; p = 0.002). Thawed samples equally showed interstitial oedema and increased stromal cell vacuolization and chromatin clumping. Ki67 positive staining of active proliferating cells revealed a comparable proportion of viable follicles between thawed samples (46.3 ± 20.8 vs. 28.3 ± 27.9 for PROH+S and S Group, respectively; p = 0.2). Finally, the expression of the endothelial marker CD31 in the thawed samples suggested an equivalent number of blood vessels per mm2 (43.8 ± 34.3 vs. 41.7 ± 44.8; p = 0.6).

Limitations, reasons for caution

Single centre study with a limited sample size. Only 24h of in vitro culture was assessed. The use of the freezing medium corresponding to the Sucrose only solution was not tested. Clinical outcomes after ovarian tissue transplantation should be evaluated before drawing final conclusion.

Wider implications of the findings

First evidence of the feasible application of a “Universal Warming” protocol, irrespective of brand and cryoprotectants, for the rapid thawing of slow-frozen human ovarian tissue. IVF centres would be provided with alternative options to thaw ovarian tissue for restoring reproductive potential in cancer patient undergoing ovarian transplantation.

Trial registration number

Not applicable

Effect of rLH Supplementation during Controlled Ovarian Stimulation for IVF: Evidence from a Retrospective Analysis of 1470 Poor/Suboptimal/Normal Responders Receiving Either rFSH plus rLH or rFSH Alone

We retrospectively studied a real-life population of 1470 women undergoing IVF, with poor/suboptimal/normal ovarian responsiveness to controlled ovarian stimulation (COS), comparing the cumulative live birth rate (cLBR) when COS was performed using rFSH alone or rFSH + rLH in a 2:1 ratio. Overall, we observed significantly higher cLBR in the rFSH alone group than in the rFSH + rLH group (29.3% vs. 22.2%, p < 0.01). However, considering only suboptimal/poor responders (n = 309), we observed comparable cLBR (15.6% vs. 15.2%, p = 0.95) despite the fact that patients receiving rFSH + rLH had significantly higher ages and worse ovarian reserve markers. The equivalent effectiveness of rFSH + rLH and rFSH alone was further confirmed after stratification according to the number of oocytes retrieved: despite basal characteristics were still in favor of rFSH alone group, the cLBR always resulted comparable. Even subdividing patients according to the POSEIDON classification, irrespective of differences in the baseline clinical characteristics in favor of FSH alone group, the cLBR resulted comparable in all subgroups. Despite the retrospective, real-life analysis, our data suggest that rLH supplementation in COS may represent a reasonable option for patients with predictable or unexpected poor/suboptimal ovarian responsiveness to FSH, those matching the Bologna criteria for poor responsiveness, and those included in the POSEIDON classification.

Second stimulation in the same ovarian cycle: an option to fully-personalize the treatment in poor prognosis patients undergoing PGT-A

PURPOSE

Our primary objective was to assess whether immediately undergoing a second stimulation in the same ovarian cycle (DuoStim) for advanced-maternal-age and/or poor-ovarian-reserve (AMA/POR) patients obtaining ≤ 3 blastocysts for preimplantation-genetic-testing-for-aneuploidies (PGT-A) is more efficient than the conventional-approach.

METHODS

All AMA/POR patients obtaining ≤ 3 blastocysts after conventional-stimulation between 2017 and 2019 were proposed DuoStim, and 143 couples accepted (DuoStim-group) and were matched for the main confounders to 143 couples who did not accept (conventional-group). GnRH-antagonist protocol with recombinant-gonadotrophins and agonist trigger, intra-cytoplasmatic-sperm-injection (ICSI) with ejaculated sperm, PGT-A and vitrified-warmed euploid single-blastocyst-transfer(s) were performed. The primary outcome was the cumulative-live-birth-delivery-rate per intention-to-treat (CLBdR per ITT) within 1 year. If not delivering, the conventional-group had 1 year to undergo another conventional-stimulation. A cost-effectiveness analysis was also conducted.

RESULTS

The CLBdR was 10.5% in the conventional-group after the first attempt. Only 12 of the 128 non-pregnant patients returned (165 ± 95 days later; drop-out = 116/128,90.6%), and 3 delivered. Thus, the 1-year CLBdR was 12.6% (N = 18/143). In the DuoStim-group, the CLBdR was 24.5% (N = 35/143; p = 0.01), 2 women delivered twice and 13 patients have other euploid blastocysts after a LB (0 and 2 in the conventional-group). DuoStim resulted in an incremental-cost-effectiveness-ratio of 23,303€. DuoStim was costlier and more effective in 98.7% of the 1000 pseudo-replicates generated through bootstrapping, and the cost-effectiveness acceptability curves unveiled that DuoStim would be more cost-effective than the conventional-approach at a willingness-to-pay threshold of 23,100€.

CONCLUSIONS

During PGT-A treatments in AMA/POR women, DuoStim can be suggested in progress to rescue poor blastocyst yields after conventional-stimulation. It might indeed prevent drop-out or further aging between attempts.

A Novel Xeno-Free Method to Isolate Human Endometrial Mesenchymal Stromal Cells (E-MSCs) in Good Manufacturing Practice (GMP) Conditions

The cyclic regeneration of human endometrium is guaranteed by the proliferative capacity of endometrial mesenchymal stromal cells (E-MSCs). Due to this, the autologous infusion of E-MSCs has been proposed to support endometrial growth in a wide range of gynecological diseases. We aimed to compare two different endometrial sampling methods, surgical curettage and vacuum aspiration biopsy random assay (VABRA), and to validate a novel xeno-free method to culture human E-MSCs. Six E-MSCs cell samples were isolated after mechanical tissue homogenization and cultured using human platelet lysate. E-MSCs were characterized for the colony formation capacity, proliferative potential, and multilineage differentiation. The expression of mesenchymal and stemness markers were tested by FACS analysis and real-time PCR, respectively. Chromosomal alterations were evaluated by karyotype analysis, whereas tumorigenic capacity and invasiveness were tested by soft agar assay. Both endometrial sampling techniques allowed efficient isolation and expansion of E-MSCs using a xeno-free method, preserving their mesenchymal and stemness phenotype, proliferative potential, and limited multi-lineage differentiation ability during the culture. No chromosomal alterations and invasive/tumorigenic capacity were observed. Herein, we report the first evidence of efficient E-MSCs isolation and culture in Good Manufacturing Practice compliance conditions, suggesting VABRA endometrial sampling as alternative to surgical curettage.

The effect of extended cryo-storage following vitrification on embryo competence: a systematic review and meta-analysis

PURPOSE

Few studies explored whether prolonged cryo-storage after vitrification affects embryo competence and perinatal outcomes. This systematic review and meta-analysis aims at highlighting any putative impact of cryo-storage duration on cryo-survival, miscarriage, live birth and major malformations.

METHODS

A systematic review was performed using MEDLINE (PubMed), ISI Web of Knowledge, Scopus and Embase databases up to June 2021. Data were combined to obtain a pooled OR, and meta-analysis was conducted using a random effects model. Out of 1,389 screened abstracts, 22 papers were assessed for eligibility, and 5 studies were included (N = 18,047 embryos). Prolonged cryo-storage was defined as > 12 months (N = 3389 embryos). Subgroup analysis was performed for untested vitrified cleavage stage embryos (N = 1739 embryos) and for untested and euploid vitrified blastocysts (N = 13,596 and 2712 embryos, respectively).

RESULTS

Survival rate, miscarriage, live birth and major malformation rates were all similar in the two groups.

CONCLUSION

These data further support the safety of long-term cryo-storage of human embryos beyond 12 months. This is reassuring for good prognosis patients with surplus embryos, couples seeking a second child from supernumerary embryos and women postponing the transfer for clinical or personal reasons.

Are commercial warming kits interchangeable for vitrified human blastocysts? Further evidence for the adoption of a Universal Warming protocol

PURPOSE

To study whether a new combination of different warming kits is clinically effective for vitrified human blastocysts.

METHODS

This is a longitudinal cohort study analysing two hundred fifty-five blastocysts warming cycles performed between January and October 2018. Embryos were vitrified using only one brand of ready-to-use kits (Kitazato), whereas the warming procedure was performed with three of the most widely used vitrification/warming kits (Kitazato, Sage and Irvine) after patient stratification for oocyte source. The primary endpoint was survival rate, while the secondary endpoints were clinical pregnancy, live birth and miscarriage rates.

RESULTS

We observed a comparable survival rate across all groups of 100% (47/47) in KK, 97.6% (49/50) in KS, 97.6% (41/42) in KI, 100% (38/38) in dKK, 100% (35/35) in dKS and 100% (43/43) in dKI. Clinical pregnancy rates were also comparable: 38.3% (18/47) in KK, 49% (24/49) in KS, 56.1% (23/ 41) in KI, 47.4% (18/38) in dKK, 31.4% (11/35) in dKS and 48.8% (21/ 43) in dKI. Finally, live birth rates were 29.8% (14/47) in KK, 36.7% (18/49) in KS, 46.3% (19/41) in KI, 36.8% (14/38) in dKK, 25.7% (9/35) in dKS and 41.9% (18/43) in dKI, showing no significant differences.

CONCLUSION

This study confirmed the efficacy of applying a single warming protocol, despite what the "industry" has led us to believe, supporting the idea that it is time to proceed in the cryopreservation field and encouraging embryologists worldwide to come out and reveal that such a procedure is possible and safe.

P–241 Construction of a Machine Learning algorithm based on early morphokinetics for human blastocyst development prediction: a retrospective analysis of 575 cleavage-stage embryos

Study question

Can morphokinetic features included into Machine Learning (ML) algorithms identify cleavage-stage embryos with the best chance to reach the expanded blastocyst stage on day 5?

Summary answer

A ML algorithm based on early morphokinetic features can identify cleaving embryos that will reach the expanded blastocyst stage on day 5.

What is known already

To date, the conventional morphology assessment of cleaving human embryos has a limited predictive power on further embryo developmental potential. The morphokinetic analysis using Time-Lapse systems (TLS) was introduced in order to provide a new tool to identify dynamic biomarkers of embryo quality. More recently, ML approach has been applied for the analysis of specific embryo-related features, aiming at developing predictive algorithms to assess the embryo development potential.

Study design, size, duration

We retrospectively analysed 575 embryos obtained from 80 women aged 25–42 years, with normal BMI, AFC≥8, day 3 FSH&lt;12 IU/l, AMH&gt;2.5 ng/ml, no diagnosis of polycystic ovary syndrome or endometriosis. These patients underwent IVF at our IVF Unit between March 2018 and March 2020; their embryos were cultured using the Geri plus® TLS and a single blastocyst transfer was performed.

Participants/materials, setting, methods

A total number of 29 morphological and morphokinetic parameters were considered to build six different ML algorithms. The performance to assess which was the best-fitting algorithm was calculated using the ROC curve considering accuracy (% of embryos correctly classified by the algorithm), Cohen-kappa coefficient (measurement of the agreement among features), mean number of TP (embryos correctly classified as undergoing developmental arrest), mean number of TN (embryos uncorrectly classified as undergoing developmental arrest).

Main results and the role of chance

Overall, 210 embryos progressed to the expanded blastocyst stage on day 5 (BL group), whereas 365 displayed developmental delay or arrest at any stage (nBL group). Among the six different algorithms, the best-fitting algorithm was obtained using the Kbest features selection approach combined with a Random Forrest evaluation strategy. This algorithm was based on 7 variables: embryo morphological score on day 2, pronuclear fading time (tPNf), completion time of cleavage to two, four and eight cells (t2, t4, and t8 respectively), time intervals t4-t3 and t8-t4. The algorithm showed an AUC of 0.78, with an accuracy of 0.73, a Cohen-kappa of 0.41, a mean TP number of 302/365 embryos in the nBL group and a mean TN number of 120/210 embryos in the BL group. Mean false positive (FP) and false negative (FN) numbers were of 63 and 90.2, respectively.

Limitations, reasons for caution

The results obtained in this study may not be generalizable to patients with other clinical characteristics, to other time-lapse systems or different laboratory settings. The predictive power of the algorithm should be validated prospectively on a larger number of embryos.

Wider implications of the findings: The current study represents a preliminary analysis for the development of hierarchical predictive models for embryo assessment based on their developmental potential, that embryologists will be able to apply as a support for decision-making.

Trial registration number

Not applicable

Effect of a Combination of Myo-Inositol, Alpha-Lipoic Acid, and Folic Acid on Oocyte Morphology and Embryo Morphokinetics in non-PCOS Overweight/Obese Patients Undergoing IVF: A Pilot, Prospective, Randomized Study

Herein we aimed at assessing whether Myo-Inositol (MI), Alpha–Lipoic acid (ALA), and Folic acid (FA) could improve oocyte quality and embryo development in non-PCOS overweight/obese women undergoing IVF. Three hundred and twenty-four mature oocytes were obtained from non-PCOS overweight/obese patients, randomized to receive either MI, ALA, and FA (MI + ALA + FA group, n = 155 oocytes) or FA alone (FA-only group, n = 169 oocytes). Oocytes were examined using Polarized Light Microscopy to assess morphological features of zona pellucida (ZP) and meiotic spindle (MS). One hundred and seventy-six embryos (n = 84 in the MI + ALA + FA group, n = 92 in the FA-only group) were assessed by conventional morphology on days 2 and 5, as well as using the Time-Lapse System morphokinetic analysis. A significantly higher ZP retardance, area, and thickness (p < 0.05), and a shorter MS axis (p < 0.05) were observed in the MI + ALA + FA group, suggesting a positive effect on oocyte quality. Conventional morphology evaluation on day 2 showed a higher mean embryo score in the MI + ALA + FA group, whereas embryo morphokinetic was comparable in the two groups. Overall, our data show a possible beneficial effect of the combination of MI, ALA, and FA on oocyte and embryo morphology, encouraging testing of this combination in adequately powered randomized trials to assess their impact of clinical IVF results.

Human recombinant FSH induces chemoresistance in human breast cancer cells via HIF-1α activation†

Breast cancer patients under 40 years of age who are candidate to chemotherapy with alkylating drugs may undergo controlled ovarian stimulation (COS) with recombinant human follicle-stimulating hormone (rhFSH) in order to get fertility preservation by mature oocyte cryostorage. The direct effect(s) of exogenous rhFSH on the chemosensitivity of breast cancer is currently unknown. To clarify this issue, we incubated four different breast cancer cell lines with rhFSH (10 IU/L, 24 h) and then we exposed them to doxorubicin (DOX) or cyclophosphamide (CPA). The effect(s) of rhFSH on human breast cancer cells treated with DOX or CPA was measured in terms of (1) cell viability, (2) cytotoxicity, (3) multidrug resistance (MDR) genes and proteins expression and activities, and (4) hypoxia-inducible factor 1-alpha (HIF-1α) activation. Pretreatment with rhFSH significantly increased the viability of breast cancer cells after treatment with DOX or CPA, and reduced the lactate dehydrogenase leakage and reactive oxygen species production. Moreover, after preincubation with rhFSH, the MDR proteins (Pgp, MPR1, and BCRP) expression and activity resulted upregulated and the HIF-1α pathway activated. In addition, the use of a widely used HIF-1α inhibitor, the 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1), prevented the rhFSH effect on the onset of MDR. Taken together, these observations suggest that a short exposure to rhFSH induces chemoresistance to DOX and CPA in human breast cancer cells via HIF-1α activation.

Controlled ovarian stimulation and progesterone supplementation affect vaginal and endometrial microbiota in IVF cycles: a pilot study

Purpose

Does controlled ovarian stimulation (COS) and progesterone (P) luteal supplementation modify the vaginal and endometrial microbiota of women undergoing in vitro fertilization?

Methods

Fifteen women underwent microbiota analysis at two time points: during a mock transfer performed in the luteal phase of the cycle preceding COS, and at the time of fresh embryo transfer (ET). A vaginal swab and the distal extremity of the ET catheter tip were analyzed using next-generation 16SrRNA gene sequencing. Heterogeneity of the bacterial microbiota was assessed according to both the Bray-Curtis similarity index and the Shannon diversity index.

Results

Lactobacillus was the most prevalent genus in the vaginal samples, although its relative proportion was reduced by COS plus P supplementation (71.5 ± 40.6% vs. 61.1 ± 44.2%). In the vagina, an increase in pathogenic species was observed, involving Prevotella (3.5 ± 8.9% vs. 12.0 ± 19.4%), and Escherichia coli-Shigella spp. (1.4 ± 5.6% vs. 2.0 ± 7.8%). In the endometrium, the proportion of Lactobacilli slightly decreased (27.4 ± 34.5% vs. 25.0 ± 29.9%); differently, both Prevotella and Atopobium increased (3.4 ± 9.5% vs. 4.7 ± 7.4% and 0.7 ± 1.5% vs. 5.8 ± 12.0%). In both sites, biodiversity was greater after COS (p < 0.05), particularly in the endometrial microbiota, as confirmed by Bray-Curtis analysis of the phylogenetic distance among bacteria genera. Bray-Curtis analysis confirmed significant differences also for the paired endometrium-vagina samples at each time point.

Conclusions

Our findings suggest that COS and P supplementation significantly change the composition of vaginal and endometrial microbiota. The greater instability could affect both endometrial receptivity and placentation. If our findings are confirmed, they may provide a further reason to encourage the freeze-all strategy.

ICSI Versus Conventional IVF in Women Aged 40 Years or More and Unexplained Infertility: A Retrospective Evaluation of 685 Cycles with Propensity Score Model

This study compared the cumulative live birth rates following Intracytoplasmic sperm injection (ICSI) versus conventional in vitro fertilization (cIVF) in women aged 40 years or more and unexplained infertility. A cohort of 685 women undergoing either autologous conventional IVF or ICSI was retrospectively analyzed. The effects of conventional IVF or ICSI procedure on cumulative pregnancy and live birth rates were evaluated in univariate and in multivariable analysis. In order to reduce potential differences between women undergoing either IVF or ICSI and to obtain unbiased estimation of the treatment effect, propensity score was estimated. ICSI was performed in 307 couples (ICSI group), whereas cIVF was performed in 297 couples (cIVF group), resulting in 45 and 43 live deliveries, respectively. No differences were observed in morphological embryo quality, in the number of cleavage stage embryos, in the number of transferred embryos, and in the number of vitrified embryos. As for the clinical outcome, no differences were observed in pregnancy rate, cumulative pregnancy rate, live birth rate, cumulative live birth rate, and abortion rate. The present results suggest that ICSI is not associated with increased likelihood of a live birth for unexplained, non-male factor infertility, in women aged 40 years or more.

Impact of the addition of Early Embryo Viability Assessment to morphological evaluation on the accuracy of embryo selection on day 3 or day 5: a retrospective analysis

In this study we aimed at retrospectively assessing in a homogeneous group of IVF patients whether the addition of Early Embryo Viability Assessment (Eeva™) to standard morphology increases the accuracy of embryo selection in case of double embryo transfer (DET) on day 3 or single embryo transfer (SET) on day 5. Eeva™ is an algorhythm aimed at indicating on day 3, according to morphokinetic parameters observed in the first three days of embryo growth, which embryos are more likely to develop into viable blastocysts and implant. A total number of 328 patients were included in the study; IVF or ICSI were performed and 428 embryos were transferred, either with DET on day 5, or (when at least four top scored embryos were available on day 3) with SET of day 5. Four groups were considered: (a) patients receiving day 3 DET with embryos selected by standard morphology (DET-3 M, n = 106, receiving 212 embryos), (b) patients receiving day 3 DET with embryos selected by morphology plus Eeva™ (DET-3 ME group, n = 48, receiving 96 embryos), (c) patients receiving day 5 SET with a blastocyst selected by standard morphology (SET-5 M group, n = 126, receiving 126 embryos), and (d) patients receiving day 5 SET with a blastocyst selected by morphology plus Eeva™ (SET-5 ME group, n = 48, receiving 48 embryos). Overall, a clinical pregnancy rate of 49.1%, implantation rate of 40%, and ongoing pregnancy rate of 43.6% were observed. The implantation rate was significantly higher in DET-3 ME group than in DET-3 M group (44.8% vs. 30.2%, p < 0.02), whereas it was comparable in groups DET-3 ME, SET-5 M and SET-5 ME. Differently, the ultrasound-verified clinical pregnancy rate and the ongoing pregnancy rate at 12 weeks did not significantly differ in all four groups. Overall, our findings suggest that Eeva™ algorhythm can improve embryo selection accuracy of standard morphology when ET on day 3 is scheduled, leading to a higher implantation rate, but its impact on ongoing pregnancy and live birth needs to be further clarified.

Zona pellucida gene mRNA expression in human oocytes is related to oocyte maturity, zona inner layer retardance and fertilization competence

STUDY QUESTION

Do the mRNA expression levels of zona pellucida (ZP) genes, ZP1, 2, 3 and 4 in oocyte and cumulus cells (CC) reveal relevant information on the oocyte?

SUMMARY ANSWER

The ZP mRNA expression in human oocytes is related to oocyte maturity, zona inner layer (IL) retardance and fertilization capacity.

WHAT IS KNOWN ALREADY

ZP structure and birefringence provide useful information on oocyte cytoplasmic maturation, developmental competence for embryonic growth, blastocyst formation and pregnancy. In order to understand the molecular basis of morphological changes in the ZP, in the current study, the polarized light microscopy (PLM) approach was combined with analysis of the expression of the genes encoding ZP1, 2, 3 and 4, both in the oocytes and in the surrounding CC.

STUDY DESIGN, SIZE, DURATION

This is a retrospective study comprising 98 supernumerary human cumulus oocyte complexes (COC) [80 Metaphase II (MII), 10 Metaphase I (MI) and 8 germinal vesicle (GV)] obtained from 39 patients (median age 33.4 years, range 22-42) after controlled ovarian stimulation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Single oocytes and their corresponding CC were analysed. Oocytes were examined using PLM, and quantitative RT-PCR was performed for ZP1, 2, 3 and 4 in these individual oocytes and their CC. Ephrin-B2 (EFNB2) mRNA was measured in CC as a control. Presence of ZP3 protein in CC and oocytes was investigated using immunocytochemistry. Data were analysed using one-parametric and multivariate analysis and were corrected for the potential impact of patient and cycle characteristics.

MAIN RESULTS AND THE ROLE OF CHANCE

Oocytes contained ZP1/2/3 and 4 mRNA while in CC only ZP3 was quantifiable. Also ZP3 protein was detected in human CC. When comparing mature (MII) and immature oocytes (MI/GV) or their corresponding CC, ZP1/2 and 4 expression was lower in mature oocytes compared to the expression in immature oocytes (all P < 0.05) and ZP3 expression was lower in the CC of mature oocytes compared to the expression in CC of immature oocytes (P < 0.05). This coincided with a significantly smaller IL-ZP area and thickness in mature oocytes than in immature oocytes (all P < 0.05). In mature oocytes, IL-ZP retardance was significantly correlated with the expression of all four ZP mRNAs (all P < 0.05). The oocyte ZP3 expression was the main predictor of the fertilization capacity, next to IL-retardance and IL-thickness. Using stepwise regression analysis, IL-thickness combined with EFNB2 expression in CC and the patient's ovarian response resulted in a noninvasive oocyte fertilization prediction model.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

This is a retrospective study and the relation of oocyte mRNA levels to fertilization capacity is indirect as oocyte gene expression analysis required lysis of the oocyte.

WIDER IMPLICATIONS OF THE FINDINGS

Overall relations between PLM observations, mRNA expression changes and intrinsic oocyte competence were successfully documented. As such PLM and CC gene expression are confirmed as valuable noninvasive techniques to evaluate oocyte competence.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by University of Torino, Italy, WFWG UZ-Brussel and Agentschap voor Innovatie door Wetenschap en Technologie IWT 110680, Belgium. All authors declare that their participation in the study did not involve actual or potential conflicts of interests.

Angiogenic properties of endometrial mesenchymal stromal cells in endothelial co-culture: an in vitro model of endometriosis

Study Question

Can endometrial mesenchymal stromal cells (E-MSCs) differentiate into endothelial cells in an in vitro co-culture system with human umbilical vein endothelial cells (HUVECs)?

Summary Answer

E-MSCs can acquire endothelial markers and function in a direct co-culture system with HUVECs.

What is Known Already

E-MSCs have been identified in the human endometrium as well as in endometriotic lesions. E-MSCs appear to be involved in formation of the endometrial stromal vascular tissue and the support of tissue growth and vascularization. The use of anti-angiogenic drugs appears as a possible therapeutic strategy against endometriosis.

Study Design, Size, Duration

This is an in vitro study comprising patients receiving surgical treatment of ovarian endometriosis (n = 9).

Participants/Materials, Setting, Methods

E-MSCs were isolated from eutopic and ectopic endometrial tissue and were characterized for the expression of mesenchymal and endothelial markers by FACS analysis and Real-Time PCR. CD31 acquisition was evaluated by FACS analysis and immunofluorescence after a 48 h-direct co-culture with green fluorescent protein +-HUVECs. A tube-forming assay was set up in order to analyze the functional potential of their interaction. Finally, co-cultures were treated with the anti-angiogenic agent Cabergoline.

Main Results and the Role of Chance

A subpopulation of E-MSCs acquired CD31 expression and integrated into tube-like structures when directly in contact with HUVECs, as observed by both FACS analysis and immunofluorescence. The isolation of CD31+ E-MSCs revealed significant increases in CD31, vascular endothelial growth factor receptor 2, TEK receptor tyrosine kinase and vascular endothelial-Cadherin mRNA expression levels with respect to basal and to CD31neg cells (P < 0.05). On the other hand, the expression of mesenchymal genes such as c-Myc, Vimentin, neuronal-Cadherin and sushi domain containing 2 remained unchanged. Cabergoline treatment induced a significant reduction of the E-MSC angiogenic potential (P < 0.05 versus control).

Large Scale Data

Not applicable.

Limitations, Reasons for Caution

Further studies are necessary to investigate the cellular and molecular mechanisms underlying the endothelial cell differentiation.

Wider Implications of the Findings

E-MSCs may undergo endothelial differentiation, and be potentially involved in the development of endometriotic implants. Cell culture systems that more closely mimic the cellular complexity typical of endometriotic tissues in vivo are required to develop novel strategies for treatment.

Study Funding/Competing Interest(s)

This study was supported by the 'Research Fund ex-60%', University of Turin, Turin, Italy. All authors declare that their participation in the study did not involve actual or potential conflicts of interests.

Oocyte polarized light microscopy, assay of specific follicular fluid metabolites, and gene expression in cumulus cells as different approaches to predict fertilization efficiency after ICSI

BACKGROUND

The complex relationship between oocyte morphology, specific follicular fluid metabolites, gene expression in cumulus granulosa cells, and oocyte competence toward fertilization and embryo development still needs further clarification.

METHODS

Forty-six oocytes retrieved from the largest pre-ovulatory follicle of patients undergoing intra-cytoplasmic sperm injection (ICSI) were considered assessing: (a) oocyte morphological characteristics at polarized light microscopy (PLM), (b) specific follicular fluid (FF) metabolites previously suggested to influence oocyte competence (AMH, markers of redox status and of cytotoxicity), (c) transcription of AMH and AMH type II receptor genes in cumulus cells. Data were analyzed using mono-parametric tests and multivariable logistic analysis in order to correlate morphological and biochemical data with fertilization.

RESULTS

Comparing normally fertilized oocytes (n = 29, F group) with unfertilized (n = 17, nF group) we observed that: (a) the meiotic spindle area and major axis were significantly higher in nF group and in fertilized oocytes undergoing an early embryo development arrest; (b) AMH level in FF was comparable in F and nF groups; (c) the FF of nF group contained significantly higher levels of cytotoxicity (lactate dehydrogenase) and oxidative stress (Cu,Zn-superoxide dismutase, catalase, 4-hydroxynonenal-protein conjugates) markers; (d) cumulus cells of nF group showed significantly higher AMH receptor type II gene expression.

CONCLUSIONS

Taken together, these observations suggest that an excessive cytotoxicity level can alter AMH signal transduction within cumulus cells, in turn leading to partial inhibition of aromatase activity, altered cytoplasmic maturation and increased oxidative stress, factors able to impair oocyte fertilization competence and embryo growth.

Empty follicle syndrome revisited: definition, incidence, aetiology, early diagnosis and treatment

In this review, the definition, incidence and possible causes of empty follicle syndrome (EFS), including molecular mechanisms that may underlie the syndrome, are discussed, along with prevention and treatment options. EFS is the complete failure to retrieve oocytes after ovarian stimulation, despite apparently normal follicle development and adequate follicular steroidogenesis. Two variants of EFS have been described: the 'genuine' form (gEFS), which occurs in the presence of adequate circulating HCG levels at the time of oocyte aspiration, and the 'false' form (f-EFS), which is associated with circulating HCG below a critical threshold. Heterogeneous HCG concentration thresholds, however, have been used to define gEFS, and to date no standardization exist. The situation is unclear when GnRH-analogues are used for ovulation trigger, as the threshold circulating LH and progesterone levels used to define EFS as 'genuine' are not established. The cause of fEFS has been clearly identified as an error in HCG administration at the time of ovulation trigger; in contrast, the cause of gEFS is still unclear, although some pathogenetic hypotheses have been proposed. Optimal treatment and prognosis of these patients are still poorly understood. Large, systematic multi-centre studies are needed to increase the understanding of EFS.

Controlled Ovarian Stimulation with recombinant-FSH plus recombinant-LH vs. human Menopausal Gonadotropin based on the number of retrieved oocytes: results from a routine clinical practice in a real-life population

BACKGROUND

The association of recombinant FSH (rFSH) plus recombinant LH (rLH) is currently used for Controlled Ovarian Stimulation (COS) in human IVF, but its efficacy has, to date, not yet been compared to that of human Menopausal Gonadotropin (hMG), the FSH + LH activity-containing urinary drug.

METHODS

Eight hundred forty-eight (848) IVF patients classified as expected "poor" or "normal" responders according to antral follicle count (AFC) and basal (day 3) FSH were treated with rFSH + rLH (2:1 ratio, n = 398, Group A) or hMG (n = 450, Group B). Data were collected under real-life practice circumstances and the pregnancy rate with fresh embryos was calculated by stratifying patients according to the number of retrieved oocytes (1-2, 3-4, 5-6, 7-8, >8).

RESULTS

Overall, the pregnancy rate in both groups progressively improved according to the number of oocytes retrieved. When comparing patients within the same subgroup of oocyte yield, Group A and B showed a comparable outcome up to the reported highest yield (>8). When more than 8 oocytes were available, Group A had a significantly better pregnancy rate outcome. Patients' characteristics did not significantly differ between the two groups and the better outcome in the best responding patients in Group A was confirmed by a multivariable logistic regression analysis, that showed that both the use of rFSH + rLH and the total number of retrieved oocytes increased the probability of pregnancy with odd ratio (OR) of 1.628 and 1.083, respectively.

CONCLUSIONS

When comparing patients with the same number of retrieved oocytes under real-life circumstances, the association of rFSH + rLH results in a significantly higher pregnancy rate than hMG when more than 8 oocytes are retrieved. The reason(s) for this are unknown, but a more favorable effect on oocyte quality and/or endometrial receptivity could be involved.

Inducible nitric oxide synthase and heme oxygenase 1 are expressed in human cumulus cells and may be used as biomarkers of oocyte competence

The interplay between oocyte and surrounding cumulus cells (CCs) during follicular growth influences oocyte competence to undergo fertilization and sustain embryo development. The expression of many genes and proteins in CCs has been suggested as potential biomarker of oocyte competence in human in vitro fertilization (IVF). In the present study, we analyzed 90 human cumulus-oocyte complexes obtained during IVF procedure: 30 CCs were analyzed using quantitative real-time polymerase chain reaction and 60 CCs using Western blotting analysis to detect gene and protein expression of some enzymes related to oxidative stress, that is, the 3 nitric oxide synthase (NOS) isoforms and heme oxygenase 1 (HO-1). In the group of 60 CCs, we also investigated the expression and phosphorylation of IkBα, a known inhibitor of the nuclear factor κB (NF-κB) pathway, which controls several redox-sensitive genes. The expression of the messenger RNAs (mRNAs) was related to the oocyte morphological analysis performed by polarized light microscopy and to the occurrence of normal fertilization after intracytoplasmic sperm injection. We observed that the amount of iNOS and HO-1 mRNAs and proteins is significantly higher, and that in the meanwhile the NF-κB pathway is activated, in CCs corresponding to oocytes that were not fertilized in comparison to CCs whose corresponding oocyte showed normal fertilization. Instead, no correlation between the fertilization and the oocytes' morphological data was observed. These results suggest that the increase in iNOS and HO-1 mRNAs expression in CCs is a negative index of oocyte fertilizability and might be an useful tool for oocyte selection.