Combining fertility preservation procedures to spread the eggs across different baskets: a feasibility study

A fresh start for IVM: capacitating the oocyte for development using pre-IVM

BACKGROUND

While oocyte IVM is practiced sporadically it has not achieved widespread clinical practice globally. However, recently there have been some seminal advances in our understanding of basic aspects of oocyte biology and ovulation from animal studies that have led to novel approaches to IVM. A significant recent advance in IVM technology is the use of biphasic IVM approaches. These involve the collection of immature oocytes from small antral follicles from minimally stimulated patients/animals (without hCG-priming) and an ∼24 h pre-culture of oocytes in an advanced culture system ('pre-IVM') prior to IVM, followed by routine IVF procedures. If safe and efficacious, this novel procedure may stand to make a significant impact on human ART practices.

OBJECTIVE AND RATIONALE

The objectives of this review are to examine the major scientific advances in ovarian biology with a unique focus on the development of pre-IVM methodologies, to provide an insight into biphasic IVM procedures, and to report on outcomes from animal and clinical human data, including safety data. The potential future impact of biphasic IVM on ART practice is discussed.

SEARCH METHODS

Peer review original and review articles were selected from PubMed and Web of Science searches for this narrative review. Searches were performed using the following keywords: oocyte IVM, pre-IVM, biphasic IVM, CAPA-IVM, hCG-triggered/primed IVM, natural cycle IVF/M, ex-vivo IVM, OTO-IVM, oocyte maturation, meiotic competence, oocyte developmental competence, oocyte capacitation, follicle size, cumulus cell (CC), granulosa cell, COC, gap-junction communication, trans-zonal process, cAMP and IVM, cGMP and IVM, CNP and IVM, EGF-like peptide and IVM, minimal stimulation ART, PCOS.

OUTCOMES

Minimizing gonadotrophin use means IVM oocytes will be collected from small antral (pre-dominant) follicles containing oocytes that are still developing. Standard IVM yields suboptimal clinical outcomes using such oocytes, whereas pre-IVM aims to continue the oocyte's development ex vivo, prior to IVM. Pre-IVM achieves this by eliciting profound cellular changes in the oocyte's CCs, which continue to meet the oocyte's developmental needs during the pre-IVM phase. The literature contains 25 years of animal research on various pre-IVM and biphasic IVM procedures, which serves as a large knowledge base for new approaches to human IVM. A pre-IVM procedure based on c-type natriuretic peptide (named 'capacitation-IVM' (CAPA-IVM)) has undergone pre-clinical human safety and efficacy trials and its adoption into clinical practice resulted in healthy live birth rates not different from conventional IVF.

WIDER IMPLICATIONS

Over many decades, improvements in clinical IVM have been gradual and incremental but there has likely been a turning of the tide in the past few years, with landmark discoveries in animal oocyte biology finally making their way into clinical practice leading to improved outcomes for patients. Demonstration of favorable clinical results with CAPA-IVM, as the first clinically tested biphasic IVM system, has led to renewed interest in IVM as an alternative, low-intervention, low-cost, safe, patient-friendly ART approach, and especially for patients with PCOS. The same new approach is being used as part of fertility preservation in patients with cancer and holds promise for social oocyte freezing.

Outcomes of Different In Vitro Maturation Procedures for Oocyte Cryopreservation for Fertility Preservation and yet Another Live Birth in a Cancer Patient

To ensure patient care in an oncological fertility preservation (FP) programme, specialists must provide technology that best suits the patients' clinical conditions. In vitro oocyte maturation (IVM) and ovarian tissue cryopreservation (OTC) are possible fertility preservation treatments for women in need of urgent oncological treatment. IVM consists of the retrieval of immature oocytes from small antral follicles, with no or minimal ovarian stimulation by gonadotropins. Therefore, IVM has become a pertinent option for fertility preservation, especially for cases whereby ovarian stimulation is unfeasible or contra-indicated. Existing data on immature oocytes, retrieved transvaginally (OPU-IVM) or extracted from ovarian tissue 'ex vivo' (OTO-IVM), are still limited on technical consistency, efficacy, and safety. The present retrospective cohort study includes 89 women undergoing fertility preservation using IVM methodologies and 26 women undergoing ovarian stimulation (OS) in concomitant period. In total, 533 immature oocytes were collected from IVM patients, achieving a maturation rate of 57% and 70% in OTO-IVM and 73% and 82% in OPU-IVM at 24 h and 48 h in culture, respectively. The observed high maturation rates might be due to the use of patients' serum in its innate status, i.e., without heat-inactivation. This permitted 7.6 ± 5.7 and 4.6 ± 4.9 oocytes to be vitrified in OTO-IVM and OPU-IVM, respectively, compared to 6.8 ± 4.6 from OS patients. Regarding OS patients, two of them underwent embryo transfer following the insemination of warmed oocytes after complete remission, resulting in a single live birth from one patient. Upon follow-up of two OTO-IVM patients after the termination of their oncological treatment, a total of 11 warmed oocytes lead to a transfer of a single embryo, but pregnancy was not achieved. From OPU-IVM, six embryos were transferred in three patients 4.25 years after oocyte vitrification, leading to the live birth of a healthy boy. The present case of live birth is among the first cases reported so far and supports the notion that IVM might be a relevant and safe FP option for cancer patients when oocyte preservation is required but ovarian stimulation is contra-indicated.

Current Trends on Bioengineering Approaches for Ovarian Microenvironment Reconstruction

Ovarian tissue has a unique microarchitecture and a complex cellular and molecular dynamics that are essential for follicular survival and development. Due to this great complexity, several factors may lead to ovarian insufficiency, and therefore to systemic metabolic disorders and female infertility. Techniques currently used in the reproductive clinic such as oocyte cryopreservation or even ovarian tissue transplant, although effective, have several limitations, which impair their wide application. In this scenario, mimetic ovarian tissue reconstruction comes as an innovative alternative to develop new methodologies for germ cells preservation and ovarian functions restoration. The ovarian extracellular matrix (ECM) is crucial for oocyte viability maintenance, once it acts actively in folliculogenesis. One of the key components of ovarian bioengineering is biomaterials application that mimics ECM and provides conditions for cell anchorage, proliferation, and differentiation. Therefore, this review aims at describing ovarian tissue engineering approaches and listing the main limitations of current methods for preservation and reestablishment of ovarian fertility. In addition, we describe the main elements that structure this study field, highlighting the main advances and the challenges to overcome to develop innovative methodologies to be applied in reproductive medicine. Impact Statement This review presents the main advances in the application of tissue bioengineering in the ovarian tissue reconstruction to develop innovative solutions for ovarian fertility reestablishment.

Microencapsulation and nanowarming enables vitrification cryopreservation of mouse preantral follicles

Preantral follicles are often used as models for cryopreservation and in vitro culture due to their easy availability. As a promising approach for mammalian fertility preservation, vitrification of preantral follicles requires high concentrations of highly toxic penetrating cryoprotective agents (up to 6 M). Here, we accomplish low-concentration-penetrating cryoprotective agent (1.5 M) vitrification of mouse preantral follicles encapsulated in hydrogel by nanowarming. We find that compared with conventional water bath warming, the viability of preantral follicles is increased by 33%. Moreover, the cavity formation rate of preantral follicles after in vitro culture is comparable to the control group without vitrification. Furthermore, the percentage of MII oocytes developed from the vitrified follicles, and the birth rate of offspring following in vitro fertilization and embryo transfer are also similar to the control group. Our results provide a step towards nontoxic vitrification by utilizing the synergistic cryoprotection effect of microencapsulation and nanowarming.

Ovarian tissue cryopreservation in Malaysia: a case series

OBJECTIVES

We aim to discuss the hematological cancer cases that opted for ovarian tissue cryopreservation (OTC) as fertility preservation before the gonadotoxic chemotherapy agent.

CASE PRESENTATION

The ovarian tissue cryopreservation (OTC) was started in August 2020 in our center. Up to now, there were four cases have been performed and included in this report. The ovarian tissue cortex was cryopreserved with cryoprotectant using Kitazato™ (Tokyo, Japan) media and fit in the closed system devices. A total of four post-OTC patients were included. The mean age was 24 years old, whereas the mean serum AMH level was 30.43 pmol/L. Most of them were diagnosed with lymphoma, except one was leukemia. All of them received additional GnRH analog following OTC as a chemoprotective agent before cancer treatment. Currently, they are recovering well and on regular follow-up with the hematological department.

CONCLUSIONS

Although The OTC is an ultimate option for prepubertal girls, it can be proposed as a good strategy for adult cancer women who could not delay cancer therapy.

A Systematic Review of Ovarian Tissue Transplantation Outcomes by Ovarian Tissue Processing Size for Cryopreservation

Ovarian tissue cryopreservation (OTC) is the only pre-treatment option currently available to preserve fertility for prepubescent girls and patients who cannot undergo ovarian stimulation. Currently, there is no standardized method of processing ovarian tissue for cryopreservation, despite evidence that fragmentation of ovaries may trigger primordial follicle activation. Because fragmentation may influence ovarian transplant function, the purpose of this systematic review was (1) to identify the processing sizes and dimensions of ovarian tissue within sites around the world, and (2) to examine the reported outcomes of ovarian tissue transplantation including, reported duration of hormone restoration, pregnancy, and live birth. A total of 2,252 abstracts were screened against the inclusion criteria. In this systematic review, 103 studies were included for analysis of tissue processing size and 21 studies were included for analysis of ovarian transplantation outcomes. Only studies where ovarian tissue was cryopreserved (via slow freezing or vitrification) and transplanted orthotopically were included in the review. The size of cryopreserved ovarian tissue was categorized based on dimensions into strips, squares, and fragments. Of the 103 studies, 58 fertility preservation sites were identified that processed ovarian tissue into strips (62%), squares (25.8%), or fragments (31%). Ovarian tissue transplantation was performed in 92 participants that had ovarian tissue cryopreserved into strips (n = 51), squares (n = 37), and fragments (n = 4). All participants had ovarian tissue cryopreserved by slow freezing. The pregnancy rate was 81.3%, 45.5%, 66.7% in the strips, squares, fragment groups, respectively. The live birth rate was 56.3%, 18.2%, 66.7% in the strips, squares, fragment groups, respectively. The mean time from ovarian tissue transplantation to ovarian hormone restoration was 3.88 months, 3.56 months, and 3 months in the strips, squares, and fragments groups, respectively. There was no significant difference between the time of ovarian function' restoration and the size of ovarian tissue. Transplantation of ovarian tissue, regardless of its processing dimensions, restores ovarian hormone activity in the participants that were reported in the literature. More detailed information about the tissue processing size and outcomes post-transplant are required to identify a preferred or more successful processing method.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk], identifier [CRD42020189120].

In vitro maturation of immature oocytes for fertility preservation in cancer patients compared to control patients with fertility problems in an in vitro fertilization program

Background

The aim of this study was to determine whether in vitro maturation (IVM) of immature oocytes after controlled hormonal stimulation of the ovaries could be important in cancer patients to improve their chances of conception in the future.

Patients and methods

After ovarian stimulation in cancer patients, the number of oocytes and their quality and maturity were compared to control patients with fertility problems in the in vitro fertilization (IVF) program. In both groups of patients, immature oocytes at the developmental stage of germinal vesicle were matured in vitro and the proportion of oocytes that matured in vitro was compared between groups. In a subset of women with fertility problems, intracytoplasmic sperm injection (ICSI) was performed on IVM oocytes to assess their ability to be fertilized and develop into an embryo compared to vivo matured oocytes in the same cycles and consider the procedure in cancer patients.

Results

In patients with different cancers, the disease did not affect the number and quality of retrieved oocytes. In cancer patients, there was even a significantly lower proportion of immature oocytes than in patients with fertility problems (30.0% vs. 43.6%; P < 0.05). However, in patients with cancer, fewer oocytes per patient matured in vitro than in patients with fertility problems (1.39 ± 1.04 vs. 2.48 ± 1.83; P < 0.05). After ICSI, the proportions of fertilized oocytes and fertilized oocytes developing into an embryo did not differ between oocytes matured in vitro and in vivo in the same cycles.

Conclusions

Oocyte IVM is proving to be a reliable procedure for resolving immature oocytes after controlled ovarian stimulation in cancer patients.

Female Oncofertility: Current Understandings, Therapeutic Approaches, Controversies, and Future Perspectives

Recent advances in early detection and oncological therapies have ameliorated the survival rate of young cancer patients. Yet, ovarian impairment induced by chemotherapy and radiotherapy is still a challenging issue. This review, based on clinical and lab-based studies, summarizes the evidence of gonadotoxicity of chemoradiotherapy, the recent approaches, ongoing controversies, and future perspectives of fertility preservation (FP) in female patients who have experienced chemo- or radio-therapy. Existing data indicate that chemotherapeutic agents induce DNA alterations and massive follicle activation via the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. Meanwhile, the radiation causes ionizing damage, leading to germ cell loss. In addition to the well-established methods, numerous therapeutic approaches have been suggested, including minimizing the follicle loss in cryopreserved ovarian grafts after transplantation, in vitro activation or in vitro growing of follicles, artificial ovarian development, or fertoprotective adjuvant to prevent ovarian damage from chemotherapy. Some reports have revealed positive outcomes from these therapies, whereas others have demonstrated conflictions. Future perspectives are improving the live birth rate of FP, especially in patients with adverse ovarian reserve, eliminating the risk of malignancy reintroducing, and increasing society’s awareness of FP importance.

Longitudinal study of AMH variations in 122 Adolescents and Young Adults (AYA) and non-AYA lymphoma patients to evaluate the chemo-induced ovarian toxicity to further personalise fertility preservation counselling

STUDY QUESTION

What is the influence of age and chemotherapy regimen on the longitudinal blood anti-Müllerian hormone (AMH) variations in a large series of adolescents and young adult (AYA) (15-24 years old) and non-AYA (25-35 years old) lymphoma patients?

SUMMARY ANSWER

In case of alkylating regimen treatment, there was a deep and sustained follicular depletion in AYA as well as non-AYA patients; however in both groups, the ovarian toxicity was extremely low in cases of non-alkylating treatments.

WHAT IS KNOWN ALREADY

AMH is now well-recognised to be a real-time indicator of ovarian follicular depletion and recovery in women treated by chemotherapy. Its longitudinal variations may discriminate between highly and minimally toxic protocols regarding ovarian function. It has been shown, in different cancer types, that age, type of chemotherapy regimen and pre-treatment AMH levels are the main predictors of ovarian recovery. Large studies on longitudinal AMH variations under chemotherapy in lymphoma patients are few but can provide the opportunity to assess the degree of follicle loss at a young age.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study was conducted in the Fertility Observatory of the Lille University Hospital. Data were collected between 2007 and 2016. Non-Hodgkin or Hodgkin lymphoma patients (n = 122) between 15 and 35 years old were prospectively recruited before commencing chemotherapy. Patients were treated either by a non-alkylating protocol (ABVD group; n = 67) or by an alkylating regimen (alkylating group; n = 55).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Serial AMH measurements were performed at baseline (AMH0), 15 days after the start of chemotherapy (AMH1), 15 days before the last chemotherapy cycle (AMH2), and at time 3, 6, 9, 12, 18 and 24 months from the end of chemotherapy. The whole study population was divided into two groups according to age: AYA (15-24; n = 65) and non-AYA (25-35; n = 57). All patients received a once monthly GnRH agonist injection during the whole treatment period. A linear mixed model was used to account for the repeated measures of single patients.

MAIN RESULTS AND THE ROLE OF CHANCE

At baseline, non-AYA patients had higher BMI and lower AMH levels than AYA patients. All AYA and non-AYA patients having received ABVD protocols had regular cycles at 12 months of follow-up. In case of alkylating regimens, amenorrhoea was more frequent in non-AYA patients than in AYA patients at 12 months (37% vs 4%, P = 0.011) and at 24 months (24% vs 4%, P = 0.045). We distinguished a similar depletion phase from AMH0 to AMH2 between ABVD and alkylating groups but significantly different recovery phases from AMH2 to AMH + 24 months. AMH recovery was fast and complete in case of ABVD protocols whatever the age: AMH reached pre-treatment values as soon as the 6th month of follow-up in the AYA group (mean (95% CI) in log AMH M0 vs M6: 3.07 (2.86 to 3.27) vs 3.05 (2.78 to 3.31), P = 1.00) and in the non-AYA group (mean (95% CI) in log AMH M0 vs M6: 2.73 (2.40 to 3.05) vs 2.47 (2.21 to 2.74), P = 1.00). In contrast, no patients from the alkylating group returned to pre-treatment AMH values whatever the age of patients (AYA or non-AYA). Moreover, none of the AMH values post-chemotherapy in the non-AYA group were significantly different from AMH2. Conversely in the AYA group, AMH levels from 6 months (mean (95% CI) in log AMH: 1.79 (1.47 to 2.11), P < 0.001) to 24 months (mean (95% CI) in log AMH: 2.16 (1.80 to 2.52), P ≤ 0.001) were significantly higher than AMH2 (mean (95% CI) in log AMH: 1.13 (0.89 to 1.38)). Considering the whole study population (AYA and non-AYA), pre-treatment AMH levels influenced the pattern of the AMH variation both in alkylating and ABVD protocols (interaction P-value = 0.005 and 0.043, respectively). Likewise, age was significantly associated with the pattern of the recovery phase but only in the alkylating group (interaction P-value =0.001). BMI had no influence on the AMH recovery phase whatever the protocol (interaction P-value = 0.98 in alkylating group, 0.72 in ABVD group).

LIMITATIONS, REASONS FOR CAUTION

There was a large disparity in subtypes of protocols in the alkylating group. The average duration of chemotherapy for patients treated with alkylating protocols was longer than that for patients treated with ABVD.

WIDER IMPLICATIONS OF THE FINDINGS

These results make it possible to develop strategies for fertility preservation according to age and type of protocol in a large series of young lymphoma patients. In addition, it was confirmed that young age does not protect against ovarian damage caused by alkylating agents.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Agence Régionale de Santé Hauts de France and Agence Onco Hauts-de-France who provided finances for AMH dosages (n° DOS/SDES/AR/FIR/2019/282). There are no competing interests.

TRIAL REGISTRATION NUMBER

DC-2008-642 and CNIL DEC2015-112.

Perspectives on the development and future of oocyte IVM in clinical practice

Oocyte in vitro maturation (IVM) is an assisted reproductive technology designed to obtain mature oocytes following culture of immature cumulus–oocyte complexes collected from antral follicles. Although IVM has been practiced for decades and is no longer considered experimental, the uptake of IVM in clinical practice is currently limited. The purpose of this review is to ensure reproductive medicine professionals understand the appropriate use of IVM drawn from the best available evidence supporting its clinical potential and safety in selected patient groups. This group of scientists and fertility specialists, with expertise in IVM in the ART laboratory and/or clinic, explore here the development of IVM towards acquisition of a non-experimental status and, in addition, critically appraise the current and future role of IVM in human ART.

Preservation of female fertility: The current therapeutic strategy

BACKGROUND

Preservation of female fertility is a relatively new field in medicine that has grown very rapidly in recent decades. At the beginning, embryo freezing remained the most effective technique. Thereafter, cryopreservation of oocytes and ovarian tissue was considered a secure tool in human fertility preservation. Storage of cortical ovarian tissue is moreover relevant for children, prepubertal girls, and adult patients who cannot benefit from cryopreservation of oocytes.

OBJECTIVE

To analyze and review recent and relevant scientific literature on medical and social reasons for preservation of fertility.

METHODS

The review was conducted based on articles identified from PubMed databases using keywords.

MAIN RESULTS

Oocyte vitrification allows women to preserve their fertility without the need for fertilization. Nowadays, thousands of healthy children have been born from this procedure. Occurrence of pregnancy depends on two main factors: the number of mature oocytes in storage and the age of the patient at the time of vitrification. Numerous adaptations have been developed to suit the ovarian stimulation regiments to patients with cancer. In young prepubertal girls, freezing of ovarian tissue remains the best and only option.

CONCLUSION

Oocyte vitrification therefore appears to be the gold standard technique of preserving fertility in young women.

Live birth rate after use of cryopreserved oocytes or embryos at the time of cancer diagnosis in female survivors: a retrospective study of ten years of experience

PURPOSE

The aim of this study was to evaluate the outcomes of frozen oocytes or embryos cryopreserved after controlled ovarian stimulation (COS) or in vitro maturation (IVM) for female cancer patients who underwent a fertility preservation (FP) prior to gonadotoxic therapy.

METHODS

A retrospective cohort study from 2009 to December 2017 was conducted. Among the 667 female cancer patients who underwent oocytes or embryos cryopreservation for FP, 40 (6%) have returned to the fertility clinic between 2011 and 2019 to use their frozen material after being cured. We compared these thaw cycles outcomes according to the techniques used at the time of cryopreservation.

RESULTS

Among the 40 women cancer survivors who used their cryopreserved material, thirty patients have benefited from at least one embryo transfer. Ten patients did not have an embryo transfer since the oocytes did not survive after the thawing process or because no embryo was obtained after fertilization. We related three live births following FP using IVM (two from frozen oocytes and one after embryo cryopreservation). Five live births were obtained when COS was performed at the time of FP (one from frozen oocytes and four after embryo cryopreservation).

CONCLUSIONS

Our preliminary results, although they are obtained in a small sample, are encouraging and show that different FP techniques can be used in female cancer patients and lead to live births. IVM is one of the options available that does not delay the start of chemotherapy or if ovarian stimulation using gonadotropins is contraindicated.