Oocyte versus embryo vitrification for delayed embryo transfer: an observational study

Effects of resveratrol on HIF-1α/VEGF pathway and apoptosis in vitrified duck ovary transplantation

Preservation of ovarian tissues is an effective way to ensure genetic diversity of susceptible natural bird populations that are in danger of extinction. We examined whether the addition of the plant phenol resveratrol to vitrification solutions ameliorates the damaging effects of tissue hypoxia and reperfusion injury when the tissues are transplanted. Duck ovary tissues were frozen in the presence of varying concentrations of resveratrol in cryopreservation solutions and then transplanted under the renal capsules of 2-day-old Shelducks. Samples of the transplanted tissues were examined on days 3- and 9- post transplantation for activation of hypoxia-, antioxidant- and apoptosis-related gene expression and apoptosis. Resveratrol significantly increased expression of VEGF, HIF-1α, Nrf2, CAT and Bcl-2 mRNA and decreased BAX and Caspase-3 mRNA and reduced numbers of TUNEL-positive cells after vitrification and heterotopic ovarian transplantation. Resveratrol improved the antioxidant capacity, reduced apoptosis and activated the HIF-1α/VEGF pathway to promote angiogenesis 3- and 9-days following transplantation. These results indicated that the addition of resveratrol to vitrification solutions intended for long-term cryopreservation of ovary tissues improves survival in storage and the grafts following transplantation. This study provides a theoretical basis for the successful transplantation of avian ovarian tissue after vitrification.

Oocyte and embryo cryopreservation in assisted reproductive technology: past achievements and current challenges

Cryopreservation has revolutionized the treatment of infertility and fertility preservation. This review summarizes the milestones that paved the way to the current routinary clinical implementation of this game-changing practice in assisted reproductive technology. Still, evidence to support "the best practice" in cryopreservation is controversial and several protocol adaptations exist that were described and compared here, such as cumulus-intact vs. cumulus-free oocyte cryopreservation, artificial collapse, assisted hatching, closed vs. open carriers, and others. A last matter of concern is whether cryostorage duration may impact oocyte/embryo competence, but the current body of evidence in this regard is reassuring. From social and clinical perspectives, oocyte and embryo cryopreservation has evolved from an afterthought when assisted reproduction was intended for immediate pregnancy with supernumerary embryos of secondary interest to its current purpose, which primarily is to preserve fertility long-term and more comprehensively allow for family planning. However, the initial consenting process, which still is geared to short-term fertility care, may no longer be relevant when the individuals that initially preserved the tissues have completed their reproductive journey. A more encompassing counseling model is required to address changing patient values over time.

Novel Approaches Used in Ovarian Tissue Transplantation for Fertility Preservation: Focus on Tissue Engineering Approaches and Angiogenesis Capacity

Due to the impact of the modern lifestyle, female infertility has been reduced because of different reasons. For example, in combined chemotherapeutic therapies, a small fraction of cancer survivors has faced different post-complications and side effects such as infertility. Besides, in modern society, delayed age of childbearing has also affected fertility. Nowadays, ovarian tissue cryopreservation and transplantation (OTC/T) is considered one of the appropriate strategies for the restoration of ovarian tissue and bioactivity in patients with the loss of reproductive function. In this regard, several procedures have been considered to improve the efficacy and safety of OTT. Among them, a surgical approach is used to transplant ovaries into the optimal sites, but the existence of ischemic changes and lack of appropriate revascularization can lead to bulk follicular atresia. Besides, the role of OTC/T is limited in women of advanced maternal age undergoing lifesaving chemo-radiation. As a correlate, the development of de novo approaches with efficacious regenerative outcomes is highly welcomed. Tissue engineering shows high therapeutic potentialities to restore fertility in males and females using the combination of biomaterials, cells, and growth factors. Unfortunately, most synthetic and natural materials are at the experimental stage and only the efficacy has been properly evaluated in limited cases. Along with these descriptions, strategies associated with the induction of angiogenesis in transplanted ovaries can diminish the injuries associated with ischemic changes. In this review, the authors tried to summarize recent techniques, especially tissue engineering approaches for improving ovarian function and fertility by focusing on angiogenesis and neovascularization.

Evidence-based outcomes after oocyte cryopreservation for donor oocyte in vitro fertilization and planned oocyte cryopreservation: a guideline

OBJECTIVE

To provide evidence-based recommendations to practicing physicians and others regarding the efficacy of oocyte cryopreservation (OC) for donor oocyte in vitro fertilization and planned OC.

METHODS

The American Society for Reproductive Medicine conducted a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 1986 to 2018. The American Society for Reproductive Medicine Practice Committee and a task force of experts used available evidence and through consensus developed evidence-based guideline recommendations.

MAIN OUTCOME MEASURE(S)

Outcomes of interest included live birth rate, clinical pregnancy rate, obstetrical and neonatal outcomes, and factors predicting reproductive outcomes.

RESULT(S)

The literature search identified 30 relevant studies to inform the evidence base for this guideline.

RECOMMENDATION(S)

Evidence-based recommendations were developed for predicting the likelihood of live births after planned OC, autologous OC in infertile women, and donor OC, as well as factors that may impact live birth rates. Recommendations were developed regarding neonatal outcomes after using fresh vs. cryopreserved oocytes in cases of autologous or donor oocytes.

CONCLUSION(S)

There is insufficient evidence to predict live birth rates after planned OC. On the basis of limited data, ongoing and live birth rates appear to be improved for women who undergo planned OC at a younger vs. older age. Although there are no significant differences in per transfer pregnancy rates with cryopreserved vs. fresh donor oocytes, there is insufficient evidence that the live birth rate is the same with vitrified vs. fresh donor oocytes. Neonatal outcomes appear similar with cryopreserved oocytes compared with fresh oocytes. Future studies that compare cumulative live birth rates are needed.

ARTIFICIAL OOCYTE ACTIVATION IMPROVES THE LABORATORY AND CLINICAL OUTCOME IN VITRIFIED DONOR OOCYTE GROUP

Introduction: Oocyte donation is proved effective. Vitrification of donor eggs allows creation of donor egg banking. Simultaneously, for good clinical outcome it is recommended to thaw 10-15 oocytes at once. In the current study, we demonstrate the benefit of using artificial oocyte activation in order to reduce the number of thawed donor eggs for IVF program without any affect on laboratory and clinical outcome. Aim of study: To improve the good quality blastocyst formation rate using artificial activation with vitrified donor eggs. Is it possible to increase the clinical pregnancy rate (CPR) and live birth rate (LBR) thawing only 6-8 donor eggs? Materials and Methods: The retrospective cohort studyincluded 40 fresh (Group A) and 12 vitrified (Group B) donor egg programs. ICSI was conducted to all oocytes. In Group B, we also used artificial oocyte activation with calcium ionophore. Student T test was used to infer statistical significance. P value < 0.05 was considered significant. Results: The fertilization and good quality blastocyst formation rate is not different between the groups. The majority of usable blastocysts, 72% in Group A and 93% in Group B were formed on Day 5. The CPR is not statistically different between groups A and B and is 52.5% and 50% respectively. The IR is not statistically significant and is 39% in Group A and 42% in Group B. The LBR is higher in Group A (50%) comparing to Group B (25%), but the difference is not statistically significant. Conclusions: Considering our data, we suggest that artificial oocyte activation is feasible for use with vitrified donor eggs. It might decrease the expenses of patients on thawing less number of donor oocytes without negative impact on the laboratory and clinical outcome.

Competence of embryos showing transient developmental arrest during in vitro culture

PURPOSE

In vitro developing embryos may apparently show no developmental progress during 24 h and resume their development up to the blastocyst stage. The present study was conducted to assess their ability to implant and to give rise to a live birth when replaced at day 5 (fresh or vitrified/warmed) as compared to continuously developing embryos.

METHODS

Embryo development follow-up and grade were prospectively recorded in a photo database. The studied period was from April 2011 to July 2017. The studied embryos included transient arrested embryos (TAE) that showed the same developmental stage at two subsequent observations, i.e. between day 2 and day 3 (d2 and d3), between day 3 and day 4 (d3 and d4) and between day 4 and day 5 (d4 and d5). TAE were compared to continuously developing embryos (CDE). Elective day 5 embryo transfers were performed.

RESULTS

Woman age was higher in TAE (34.3±3.9) than in CDE (32.9±4.8) (p<0.01). TAE were more frequently (63.1%) observed after ICSI than after conventional IVF (55.9%) (p<0.01). Implantation rate was reduced in TAE as compared to CDE, after both fresh (10.0% vs 23.8% [p<0.01]) and vitrified/warmed (12.9% vs 19.0% [p<0.01]) embryo transfers. Delivery rate was also lower after the transfer of fresh (8.3% vs 19.4% [p<0.01]) and vitrified/warmed (8.5% vs 14.1% [p<0.01]) TAE as compared to CDE. Implantation and delivery rates were not statistically different whether embryo arrested between day 2 and day 3 (d2 and d3), between day 3 and day 4 (d3 and d4) or between day 4 and day 5 (d4 and d5).

CONCLUSION

TAE may be considered for transfer at a lower priority than CDE and associated with inferior prognosis than CDE.

Should we still perform fresh embryo transfers in ART?

An increasing number of researchers have alluded to the potential benefit of deferring the transfer of embryos produced during assisted reproductive technologies (ARTs) away from ovarian stimulation, using cryopreservation to enable this. The scientific evidence that may justify this recent trend in the use of the so-called 'freeze-all strategy' includes early, mostly small randomised controlled trials that have demonstrated an increase in live birth rates after elective embryo cryopreservation in certain patient populations, as well as evidence from cohort studies and retrospective analyses. What are the risks and benefits of freeze-all strategies in ART, who are the patients in whom it is likely to be advantageous, and does the current evidence allow us to identify situations when deciding that a fresh embryo transfer would be counter-productive? ART professionals are often faced with challenging clinical decisions regarding the best course of treatment for their patient. The purpose of this opinion paper is to provide a clinical guide for whether to perform a fresh embryo transfer or to opt for freezing all embryos in specific situations.

Is it worth it to cryopreserve embryos with blastulation delay at day 5?

This is a retrospective study over a 5-year period. In total, 3139 embryos were individually cryopreserved (Cryotop®) and warmed using the Kitazato vitrification/warming kit. They were classified into three categories based on their expansion degree. Transfer, implantation and pregnancy rates were assessed for each embryo category and compared using SPSS (Statistical Package for the Social Sciences) software. In total, 1139 couples enrolled in infertility treatment programme benefitted from embryo vitrification at day 5. After warming, embryos belonging to the three categories showed similar success rates. Although there was a trend towards better outcomes when grade 3 embryos were transferred, the differences did not reach statistical significance: implantation rates (n fetal sac/n embryo transferred) grade 1: 21.9%, grade 2: 22.7% and grade 3: 30.3% (=0.19). Pregnancy rate (n clinical pregnancy/n transfer) (21.9%, 22.7%, 30.3%, respectively; P=0.11). Miscarriage rate was not statistically different in the three categories (14.5%, 20.4%, 20%, respectively, P=0.51). Our overall results show that it is worth vitrifying slow kinetics embryos as they provide a non-negligible chance to give rise to a pregnancy.

What advice should we give our patients to preserve their fertility and avoid needing oocyte donation in the future? - A Social Fertility Preservation program

OBJECTIVE

To describe our fertility preservation program focusing on the number of oocytes vitrified by age.

METHODS

From January 2015 to December 2016, 686 oocyte vitrification cycles were performed in our units for the social fertility preservation program. In total, 288 were donors who donated their oocytes for our oocyte-banking program, and 398 were patients who underwent elective fertility preservation.

RESULTS

The mean numbers of COCs retrieved and vitrified oocytes were similar among the donor cycles (women under 30 years). In those patients over 36 years of age the mean numbers of COCs retrieved and vitrified oocytes were significantly lower. We also estimated the association between age and cancelation rates. Odd ratios (OR) for total cancelation was calculated between patients of 31-35 years and 41-45 years; the OR was 5.17 (95% CI 1.89 - 14.17) and increased up to 25.67 (95% CI 5.01 - 131.42) between patients 31-35 y and those older than 45 years. No differences were found between patients of 31-35 years and 36-40 years. The OR for total cancellation increased 3.83 (95% CI 2.06 - 7.11) and 19.00 (95% CI 4.56 - 79.11) between women 36-40 years and 41-45 years, and those older than 45 years, respectively. Finally, the oocyte survival rate in patients under 36 years of age was similar to that of our donor program (94% vs. 95%).

CONCLUSIONS

Based on this study, we encouraged our patients under than 36 years of age to preserve their fertility for the future.

Outcome of Oocyte Vitrification Combined with Microdissection Testicular Sperm Extraction and Aspiration for Assisted Reproduction in Men

Background

As a safety and efficacy protocol, oocyte vitrification has been widely used in IVF treatment. The aim of this study was to evaluate the outcome of ICSI-ET utilizing vitrified oocytes with sperm obtained from non-obstructive azoospermia (NOA) patients via micro-TESE.

Material/Methods

A total of 150 NOA patients underwent micro-TESE. Ten patients were unable to ejaculate and refused to accept TESA at the time of oocyte retrieval; later, these patients underwent TESA. A total of 174 obstructive azoospermia (OA) patients underwent TESA. Vitrified oocytes were used with micro-TESE in 35 cycles (group 1), and TESA in 10 cycles (group 2). Fresh oocytes were used with micro-TESE in 38 cycles (group 3) and TESA in 174 cycles (group 4).

Results

The overall sperm retrieval rate of the 150 NOA patients was 48.7% (73/150). A total of 257 cycles of ICSI-ET were conducted with testicular spermatozoa; 212 cycles utilized fresh oocytes and 45 cycles utilized vitrified oocytes. No differences were observed with fertilization (73.8%, 77.2%,72.8%, 73.6%), implantation (33.3%, 34.7%, 33.8%, 37.5%), or clinical pregnancy rates (51.4%, 60%, 52.6%, 51.7%) for groups 1 through 4, respectively (P>0.05). Developmental competence was greatest among couples using sperm obtained via TESA rather than micro-TESE, not dependent on whether vitrified or fresh oocytes were utilized. Fertilization, implantation, and clinical pregnancy rates did not differ between using fresh vs. vitrified oocytes, nor did they differ between using testicular sperm derived from men with NOA vs. men with OA.

Conclusions

Vitrified oocytes combined with micro-TESE showed similar clinical efficacy when compared with fresh oocytes.

Why all women should freeze their eggs

PURPOSE OF REVIEW

The use of oocyte cryopreservation via vitrification has increased lately, becoming a common strategy in many IVF centers. This review summarizes the current state of oocyte vitrification, by analyzing the most recent reports on its use in IVF as part of infertile treatment and its contribution to elective fertility preservation (EFP).

RECENT FINDINGS

Oocyte vitrification has become helpful for managing different clinical situations currently providing similar results to fresh oocytes. Owing to satisfactory results, oocyte vitrification is being offered to healthy women to extend their reproductive options (EFP). Although little is known about outcomes in this specific population, new evidence is starting to emerge. Currently, most women are motivated by age and lack of partner. Age is strongly related to the probability of having a child with better chances when they do EFP younger than 35. In contrast to the biological efficiency, the majority of studies show that EFP is more cost-effective at 37-38 years.

SUMMARY

Oocyte vitrification is an efficient tool which can be helpful in managing the IVF cycle. Fertility preservation providers should inform women about their specific probabilities according to their age at vitrification, making emphasis in the fact that egg freezing does not guarantee success, but increases the possibilities of having a biological child in the future.

The state of "freeze-for-all" in human ARTs

The recent development of vitrification technologies and the good outcomes obtained in assisted reproduction technologies have supported new indications for freezing and segmentation of treatment. Beyond OHSS prevention and avoidance of embryo transfers in the setting of an adverse endocrinological profile or endometrial cavity, we have witnessed a trend to shift fresh embryo transfers to frozen embryo transfers in many programs. We critically review the available evidence and suggest that freeze-all is not "for all," but should be individualized.

[Ovocyte vitrification: a tool for the future]

Ovocyte vitrification was finally authorized by the new law voted in July 2011 upon the revision of the French bioethics law. Expected for 30 years, cryopreservation of female gametes had a major impact on Assisted Reproductive Technologies (ART) practice worldwide and in our country. It brought tremendous changes in the field of reproductive biology, from intraconjugal infertility management to gamete donation, through autologous cryopreservation for fertility preservation. Although it appears to be "obvious", ovocyte vitrification seems to be barely used as a routine technique in French IVF laboratories. We will discuss the events that led to the present situation. We will also tackle the expected benefits of ovocyte vitrification especially as an alternative to embryo freezing.