Outcomes of immature oocytes collected from ovarian tissue for cryopreservation in adult and prepubertal patients

New Insights on In Vitro Maturation of Oocytes for Fertility Preservation

In the last decade, the evolution of oncofertility has sparked a resurgence of interest in in vitro maturation (IVM) due to its suitability in certain oncological scenarios where controlled ovarian hyperstimulation may not be feasible. The retrieval of immature cumulus-oocyte complexes from small antral follicles, regardless of the menstrual cycle phase, presents a swift opportunity to vitrify mature oocytes or embryos post-IVM in urgent situations or when stimulation is not advisable. Harvesting immature cumulus-oocyte complexes and immature oocytes can be achieved transvaginally or directly in the laboratory from extracorporeal ovarian tissue. Although IVM has transitioned from an experimental status due to safety validations, it relies on the intricate process of oocyte maturation. Despite successful live births resulting from IVM in fertility preservation contexts, the comparatively lower developmental competence of in vitro matured oocytes highlights the necessity to enhance IVM culture systems. Recent advancements in IVM systems hold promise in bolstering oocyte competence post-IVM, thereby narrowing the gap between IVM and outcomes from ovarian stimulation. Additionally, for optimizing the chances of conception in cancer survivors, the combination of IVM and ovarian tissue cryopreservation stands as the favored choice when ovarian stimulation is unfeasible.

Mature oocyte found during ovarian tissue cryopreservation in an early adolescent female

A 15-year-old female with Hodgkin's lymphoma underwent ovarian tissue cryopreservation for preserving fertility in Reproductive Department of Sir Run Run Shaw Hospital, Zhejiang University School of Medical after receiving one course of chemotherapy. During the ovarian tissue cryopreservation, one MⅡmature oocyte and three germinal vesicle oocytes were found. The three immature oocytes underwent in vitro maturation but failed. Ultimately, one mature oocyte and 12 ovarian cortex slices were cryopreserved using vitrification. This case indicates that for patients with established gonadal axis feedback, ovarian tissue cryopreservation may not be the only method for fertility preservation. It is advisable to consider ovarian stimulation and oocyte retrieval for oocyte cryopreservation. Alternatively, for individuals in the ovulation phase of their menstrual cycle, attempting oocyte retrieval before ovarian tissue cryopreservation to obtain mature oocytes from the natural cycle, followed by oocyte cryopreservation, may enhance the likelihood of successful fertility preservation.

Fertility preservation in hematological cancer patients

Among adolescents and young adults, hematological malignancies are the most common malignancies. Although the survival rate of hematological malignancies in young patients has been dramatically improved, due to the continuous improvement and development of tumor diagnosis and treatment options, cytotoxic therapies can significantly reduce a patient's reproductive capacity and cause irreversible infertility. The most two established solutions are embryo cryopreservation and oocyte cryopreservation which can be considered in single female. Sperm or testicular tissue cryopreservation in adult male are feasible approaches that must be considered before gonadotoxic therapy. A comprehensive consultation with reproductive specialists when once diagnosed is a significantly issue which would help those survivors who want to have children. In this article, we review germ cell toxicity, which happens during the treatment of hematological malignancies, and aims to propose safety, efficacy fertility preservation methods in younger patients with hematological malignancies.

Reduced anti-Müllerian hormone action in cumulus-oocyte complexes is beneficial for oocyte maturation without affecting oocyte competence

Anti-Müllerian hormone (AMH) is a key paracrine/autocrine factor regulating folliculogenesis in the postnatal ovary. As antral follicles mature to the preovulatory stage, AMH production tends to be limited to cumulus cells. Therefore, the present study investigated the role of cumulus cell-derived AMH in supporting maturation and competence of the enclosed oocyte. Cumulus-oocyte complexes (COCs) were isolated from antral follicles of rhesus macaque ovaries for in vitro maturation with or without AMH depletion. Oocyte meiotic status and embryo cleavage after in vitro fertilization were assessed. In vitro maturation with AMH depletion was also performed using COCs from antral follicles of human ovarian tissue. Oocyte maturation and morphology were evaluated. The direct AMH action on mural granulosa cells of the preovulatory follicle was further assessed using human granulosa cells cultured with or without AMH supplementation. More macaque COCs produced metaphase II oocytes with AMH depletion than those of the control culture. However, preimplantation embryonic development after in vitro fertilization was comparable between oocytes derived from COCs cultured with AMH depletion and controls. Oocytes resumed meiosis in human COCs cultured with AMH depletion and exhibited a typical spindle structure. The confluency and cell number decreased in granulosa cells cultured with AMH supplementation relative to the control culture. AMH treatment did not induce cell death in cultured human granulosa cells. Data suggest that reduced AMH action in COCs could be beneficial for oocyte maturation. Cumulus cell-derived AMH is not essential for supporting oocyte competence or mural granulosa cell viability.

The severity of meiotic aneuploidy is associated with altered morphokinetic variables of mouse oocyte maturation

STUDY QUESTION

Is there an association between morphokinetic variables of meiotic maturation and the severity of aneuploidy following in vitro maturation (IVM) in the mouse?

SUMMARY ANSWER

The severity of meiotic aneuploidy correlates with an extended time to first polar body extrusion (tPB1) and duration of meiosis I (dMI).

WHAT IS KNOWN ALREADY

Morphokinetic variables measured using time-lapse technology allow for the non-invasive evaluation of preimplantation embryo development within clinical assisted reproductive technology (ART). We recently applied this technology to monitor meiotic progression during IVM of mouse gametes. Whether there is a relationship between morphokinetic variables of meiotic progression and aneuploidy in the resulting egg has not been systematically examined at the resolution of specific chromosomes. Next-generation sequencing (NGS) is a robust clinical tool for determining aneuploidy status and has been reverse-translated in mouse blastocysts and oocytes. Therefore, we harnessed the technologies of time-lapse imaging and NGS to determine the relationship between the morphokinetics of meiotic progression and egg aneuploidy.

STUDY DESIGN SIZE DURATION

Cumulus-oocyte complexes were collected from large antral follicles from hyperstimulated CD-1 mice. Cumulus cells were removed, and spontaneous IVM was performed in the absence or presence of two doses of Nocodazole (25 or 50 nM) to induce a spectrum of spindle abnormalities and chromosome segregation errors during oocyte meiosis. Comprehensive chromosome screening was then performed in the resulting eggs, and morphokinetic variables and ploidy status were compared across experimental groups (control, n = 11; 25 nM Nocodazole, n = 13; 50 nM Nocodazole, n = 23).

PARTICIPANTS/MATERIALS SETTING METHODS

We monitored IVM in mouse oocytes using time-lapse microscopy for 16 h, and time to germinal vesicle breakdown (tGVBD), tPB1, and dMI were analyzed. Following IVM, comprehensive chromosome screening was performed on the eggs and their matched first polar bodies via adaptation of an NGS-based preimplantation genetic testing for aneuploidy (PGT-A) assay. Bioinformatics analysis was performed to align reads to the mouse genome and determine copy number-based predictions of aneuploidy. The concordance of each polar body-egg pair (reciprocal errors) was used to validate the results. Ploidy status was categorized as euploid, 1-3 chromosomal segregation errors, or ≥4 chromosomal segregation errors. Additionally, aneuploidy due to premature separation of sister chromatids (PSSC) versus non-disjunction (NDJ) was distinguished.

MAIN RESULTS AND THE ROLE OF CHANCE

We applied and validated state-of-the-art NGS technology to screen aneuploidy in individual mouse eggs and matched polar bodies at the chromosome-specific level. By performing IVM in the presence of different doses of Nocodazole, we induced a range of aneuploidy. No aneuploidy was observed in the absence of Nocodazole (0/11), whereas IVM in the presence of 25 and 50 nM Nocodazole resulted in an aneuploidy incidence of 7.69% (1/13) and 82.61% (19/23), respectively. Of the aneuploid eggs, 5% (1/20) was due to PSSC, 65% (13/20) to NDJ, and the remainder to a combination of both. There was no relationship between ploidy status and tGVBD, but tPB1 and the dMI were both significantly prolonged in eggs with reciprocal aneuploidy events compared to the euploid eggs, and this scaled with the severity of aneuploidy. Eggs with ≥4 aneuploid chromosomes had the longest tPB1 and dMI (P < 0.0001), whereas eggs with one to three aneuploid chromosomes exhibited intermediate lengths of time (P < 0.0001).

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

We used Nocodazole in this study to disrupt the meiotic spindle and induce aneuploidy in mouse oocytes. Whether the association between morphokinetic variables of meiotic progression and the severity of aneuploidy occurs with other compounds that induce chromosome segregation errors remain to be investigated. In addition, unlike mouse oocytes, human IVM requires the presence of cumulus cells, which precludes visualization of morphokinetic variables of meiotic progression. Thus, our study may have limited direct clinical translatability.

WIDER IMPLICATIONS OF THE FINDINGS

We validated NGS in mouse eggs to detect aneuploidy at a chromosome-specific resolution which greatly improves the utility of the mouse model. With a tractable and validated model system for characterizing meiotic aneuploidy, investigations into the molecular mechanisms and factors which may influence aneuploidy can be further elaborated. Time-lapse analyses of morphokinetic variables of meiotic progression may be a useful non-invasive predictor of aneuploidy severity.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the Bill & Melinda Gates Foundation (INV-003385). Under the grant conditions of the Foundation, a Creative Commons Attribution 4.0 Generic License has already been assigned to the Author Accepted Manuscript version that might arise from this submission. The authors have no conflict of interest to disclose.

An update on oncofertility in prepubertal females

Cancer is a life-threatening event for pediatric patients. Treatment advancements in pediatric cancer have improved prognosis, but some of these treatments have gonadotoxic potential and may affect fertility in different ways. Due to the growing interest of the research community in the life prospects of young cancer survivors, there has been a demand to intersect reproductive medicine and oncology, which is referred to as "oncofertility". There are various fertility preservation options according to gender and pubertal status, and shared decisions must take place at the time of diagnosis. This study aims to provide a critical review of current and emerging strategies for preserving and restoring fertility in prepubertal females, ranging from established methods to experimental approaches that can be offered before, during, and after anticancer therapies. Additionally, the author aims to review how clinicians' awareness of oncofertility options and the latest advancements in this field, timely referral, and proper consultations with patients and their families are vital in addressing their concerns, providing emotional support, and guiding them through the decision-making process, as well as potential barriers that may hinder the fertility preservation process.

Histological analysis of (antral) follicle density in ovarian cortex tissue attached to stripped endometriomas

PURPOSE

When resecting endometriomas with the stripping technique, in the majority of cases, a thin line of adjacent ovarian cortex is attached to the endometrioma. In this study, we performed histological analysis to determine (antral) follicle density in the ovarian cortex tissue attached to stripped endometriomas and assessed patient- and surgical characteristics that could affect this.

METHODS

Histological slides of previously removed endometriomas were assessed. Follicles in the attached ovarian tissue were classified according to maturation, and follicular density was determined. Immunofluorescent staining of antral follicles in a subset of endometriomas was also performed.

RESULTS

In 90 out of 96 included endometriomas (93.7%), ovarian tissue attached to the cyst wall was observed. One thousand nine hundred forty-four follicles at different maturation stages were identified (3 follicles/mm3). Follicle density was negatively associated with age (p < 0.001). Antral follicles (< 7-mm diameter) were present in the ovarian tissue attached to 35 endometriomas (36.5%) derived from younger patients compared to endometriomas where none were detected (30 versus 35 years, p = 0.003). Antral follicle density was 1 follicle/mm3. Based on immunofluorescence, healthy antral follicles were identified in two out of four examined endometriomas.

CONCLUSIONS

Ovarian tissue attached to stripped endometriomas holds potential as a non-invasive source for antral follicles. In theory, application of IVM could be an interesting alternative FP option in young patients with endometriomas who undergo cystectomy in order to transform the surgical collateral damage to a potential oocyte source. Our results encourage future research with fresh tissue to further assess the quality and potential of these follicles.

TRIAL REGISTRATION

Clinical Trials.gov Identifier: B21.055 (METC LDD), date of registration 12-08-2021, retrospectively registered.

Factors associated with the collection of isolated immature oocytes during ovarian tissue cryopreservation

PURPOSE

To identify patient characteristics associated with successful isolated immature oocyte retrieval (IsO) during ovarian tissue cryopreservation (OTC) and to determine whether they are predictive of the collection of larger numbers of oocytes.

METHODS

We retrospectively analyzed all patients undergoing OTC with IsO for fertility preservation over three years of activity at a university hospital. Univariate and multivariate analyses were used to identify the patients with the highest and lowest chances of oocyte recovery, and those with the largest numbers of oocytes. We also analyzed the correlation of IsO with the number of ovarian fragments collected and histological parameters.

RESULTS

We analyzed 257 consecutive patients undergoing these procedures, at a median age of 17.1 years [0.3-38.3 years]. Isolated oocytes were obtained from 47.1% of patients, and IsO was more likely in patients with ovulatory cycles (63.0% vs. 38.6%; P≤ .001), without chemotherapy before OTC (61.4% vs. 33.1; P< .001) and with non-malignant diseases other than Turner syndrome (77.5%). Oocyte collection failure rates were highest in patients with Turner syndrome (OR 25.0, 95% CI 3.99-157.0; P< .001) or undergoing chemotherapy with alkylating agents before OTC (OR 37.6, 95% CI 8.36-168.8; P< .001). Prepubescent status (P= .043) and large numbers of ovarian fragments (P< .001) were associated with the retrieval of larger numbers of oocytes. Oocyte recovery was correlated with the presence of follicles in the medulla, but not with follicular density.

CONCLUSION

The chances of IsO differ between patients. Identifying patients with the highest chances of success facilitates appropriate resource allocation.

The study of the efficiency of in vitro maturation of ovarian tissue oocytes in pediatric patients

PURPOSE

Although recent in vitro maturation (IVM) studies in pediatric patients have demonstrated successful retrieval and maturation of oocytes, the studies included only a small number of premenarchal patients. In the present study, we examined the potential use of oocyte retrieval and maturation for pediatric patients who undergo ovarian tissue cryopreservation (OTC).

METHODS

We retrospectively examined the clinical records of pediatric patients who underwent OTC at our institution between October 2015 and December 2022. Data on the age, primary disease, menstrual history, pre-procedure chemotherapy, anti-Müllerian hormone (AMH) level, number of oocytes collected ex vivo from ovarian tissue, and number of mature oocytes from IVM were examined.

RESULTS

Data of 60 pediatric patients (aged 1 to 17 years) were included for analysis. Oocytes were retrieved from 36 patients; the oocytes of 18 of these patients could be cryopreserved. The IVM rate was significantly lower in the premenarchal patients than in the postmenarchal patients. The number of mature oocytes retrieved from IVM was higher in the no-chemotherapy group than in the chemotherapy group. A significant positive correlation was observed between the AMH level and the IVM outcomes.

CONCLUSION

Oocyte retrieval and maturation in pediatric patients undergoing OTC is particularly useful in those not receiving chemotherapy. In patients receiving chemotherapy, the AMH level may be useful for predicting the IVM outcome. Activation of the oocyte maturation process in vivo in pediatric patients and better understanding of the major regulators of oocyte maturation are necessary to improve the utility of the IVM procedure.

Preservation of fertility in female patients with hematologic diseases

Recent developments of assisted reproduction techniques turned possible to avoid the infertility consequences of oncologic treatments, but fertility preservation (FP) has been somewhat neglected in women with hematologic diseases undergoing gonadotoxic treatments. For these specific cases, the current options for FP include the cryopreservation of embryos, mature oocytes and ovarian tissue, and oocyte in-vitro maturation. We intend to make patients and clinicians aware of this important and relevant issue, and provide hematologists, assisted reproduction physicians and patients, with updated tools to guide decisions for FP. The physicians of the units responsible for female FP should always be available to decide on the best-individualized FP option in strict collaboration with hematologists. With a wide range of options for FP tailored to each case, a greater level of training and information is needed among clinicians, so that patients proposed to gonadotoxic treatments can be previously advised for FP techniques in hematological conditions. ABBREVIATED ABSTRACT: Recent developments of assisted reproduction techniques turned possible to preserve the fertility of women with hematologic diseases undergoing gonadotoxic treatments. Current options for fertility preservation in women with hematologic diseases are presented. It is imperative to offer fertility preservation to all women before starting any gonadotoxic treatment and in some cases after treatment. Fertility preservation methods enable to later achieve the desired pregnancy.

FGF2, LIF, and IGF1 (FLI) supplementation during human in vitro maturation enhances markers of gamete competence

STUDY QUESTION

Does a chemically defined maturation medium supplemented with FGF2, LIF, and IGF1 (FLI) improve in vitro maturation (IVM) of cumulus-oocyte complexes (COCs) obtained from children, adolescents, and young adults undergoing ovarian tissue cryopreservation (OTC)?

SUMMARY ANSWER

Although FLI supplementation did not increase the incidence of oocyte meiotic maturation during human IVM, it significantly improved quality outcomes, including increased cumulus cell expansion and mitogen-activated protein kinase (MAPK) expression as well as enhanced transzonal projection retraction.

WHAT IS KNOWN ALREADY

During OTC, COCs, and denuded oocytes from small antral follicles are released into the processing media. Recovery and IVM of these COCs is emerging as a complementary technique to maximize the fertility preservation potential of the tissue. However, the success of IVM is low, especially in the pediatric population. Supplementation of IVM medium with FLI quadruples the efficiency of pig production through improved oocyte maturation, but whether a similar benefit occurs in humans has not been investigated.

STUDY DESIGN, SIZE, DURATION

This study enrolled 75 participants between January 2018 and December 2021 undergoing clinical fertility preservation through the Fertility & Hormone Preservation & Restoration Program at the Ann & Robert H. Lurie Children's Hospital of Chicago. Participants donated OTC media, accumulated during tissue processing, for research.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants who underwent OTC and include a pediatric population that encompassed children, adolescents, and young adults ≤22 years old. All participant COCs and denuded oocytes were recovered from media following ovarian tissue processing. IVM was then performed in either a standard medium (oocyte maturation medium) or one supplemented with FLI (FGF2; 40 ng/ml, LIF; 20 ng/ml, and IGF1; 20 ng/ml). IVM outcomes included meiotic progression, cumulus cell expansion, transzonal projection retraction, and detection of MAPK protein expression.

MAIN RESULTS AND THE ROLE OF CHANCE

The median age of participants was 6.3 years, with 65% of them classified as prepubertal by Tanner staging. Approximately 60% of participants had been exposed to chemotherapy and/or radiation prior to OTC. On average 4.7 ± 1 COCs and/or denuded oocytes per participant were recovered from the OTC media. COCs (N = 41) and denuded oocytes (N = 29) were used for IVM (42 h) in a standard or FLI-supplemented maturation medium. The incidence of meiotic maturation was similar between cohorts (COCs: 25.0% vs 28.6% metaphase II arrested eggs in Control vs FLI; denuded oocytes: 0% vs 5.3% in Control vs FLI). However, cumulus cell expansion was 1.9-fold greater in COCs matured in FLI-containing medium relative to Controls and transzonal projection retraction was more pronounced (2.45 ± 0.50 vs 1.16 ± 0.78 projections in Control vs FLIat 16 h). Additionally, MAPK expression was significantly higher in cumulus cells obtained from COCs matured in FLI medium for 16-18 h (chemiluminescence corrected area 621,678 vs 2,019,575 a.u., P = 0.03).

LIMITATIONS, REASONS FOR CAUTION

Our samples are from human participants who exhibited heterogeneity with respect to age, diagnosis, and previous treatment history. Future studies with larger sample sizes, including adult participants, are warranted to determine the mechanism by which FLI induces MAPK expression and activation. Moreover, studies that evaluate the developmental competence of eggs derived from FLI treatment, including assessment of embryos as outcome measures, will be required prior to clinical translation.

WIDER IMPLICATIONS OF THE FINDINGS

FLI supplementation may have a conserved beneficial effect on IVM for children, adolescents, and young adults spanning the agricultural setting to clinical fertility preservation.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Department of Obstetrics and Gynecology startup funds (F.E.D.), Department of Surgery Faculty Practice Plan Grant and the Fertility & Hormone Preservation & Restoration Program at the Ann & Robert H. Lurie Children's Hospital of Chicago (M.M.L. and E.E.R.). M.M.L. is a Gesualdo Foundation Research Scholar. Y.Y.'s research is supported by the internal research funds provided by Colorado Center of Reproductive Medicine. Y.Y., L.D.S., R.M.R., and R.S.P. have a patent pending for FLI. The remaining authors have no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

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.

Human ovarian gross morphology and subanatomy across puberty: insights from tissue donated during fertility preservation

Objective

To study ovarian gross morphologic and subanatomic features across pubertal development.

Design

Prospective cohort study.

Setting

An academic medical center with specimens collected from 2018-2022.

Patients

Tissue was obtained from prepubertal and postpubertal participants (0.19-22.96 years) undergoing ovarian tissue cryopreservation before treatment that put them at a significantly or high increased risk of developing premature ovarian insufficiency. Most participants (64%) had not received chemotherapy at tissue collection.

Interventions

None.

Main Outcome Measures

Ovaries procured for fertility preservation were weighed and measured. Ovarian tissue fragments released during processing, biopsies used for pathology, and hormone panels were analyzed for gross morphology, subanatomic features, and reproductive hormones. Graphical analysis of best-fit lines determined age at maximum growth velocity.

Results

Prepubertal ovaries were significantly (1.4-fold and 2.4-fold) smaller than postpubertal ovaries by length and width and 5.7-fold lighter on average. Length, width, and weight grew in a sigmoidal pattern with age. Prepubertal ovaries were less likely to display a defined corticomedullary junction (53% vs. 77% in postpubertal specimens), less likely to have a tunica albuginea (22% vs. 93% in postpubertal specimens), contained significantly more (9.8-fold) primordial follicles, and contained primordial follicles at significantly deeper depths (2.9-fold) when compared with postpubertal ovaries.

Conclusions

Ovarian tissue cryopreservation is a resource to study human ovarian biology and pubertal development. Maximum growth velocity occurs late within the pubertal transition (Tanner 3+) after changes in subanatomic features. This ovarian morphology model adds to foundational knowledge of human ovarian development and supports ongoing transcriptomics research.

Fertility preservation in pediatric healthcare: a review

Survival rates for children and adolescents diagnosed with malignancy have been steadily increasing due to advances in oncology treatments. These treatments can have a toxic effect on the gonads. Currently, oocyte and sperm cryopreservation are recognized as well-established and successful strategies for fertility preservation for pubertal patients, while the use of gonadotropin-releasing hormone agonists for ovarian protection is controversial. For prepubertal girls, ovarian tissue cryopreservation is the sole option. However, the endocrinological and reproductive outcomes after ovarian tissue transplantation are highly heterogeneous. On the other hand, immature testicular tissue cryopreservation remains the only alternative for prepubertal boys, yet it is still experimental. Although there are several published guidelines for navigating fertility preservation for pediatric and adolescent patients as well as transgender populations, it is still restricted in clinical practice. This review aims to discuss the indications and clinical outcomes of fertility preservation. We also discuss the probably effective and efficient workflow to facilitate fertility preservation.

Quantitative morphokinetic parameters identify novel dynamics of oocyte meiotic maturation and cumulus expansion†

Meiotic maturation and cumulus expansion are essential for the generation of a developmentally competent gamete, and both processes can be recapitulated in vitro. We used a closed time-lapse incubator (EmbryoScope+™) to establish morphokinetic parameters of meiotic progression and cumulus expansion in mice and correlated these outcomes with egg ploidy. The average time to germinal vesicle breakdown (GVBD), time to first polar body extrusion (PBE), and duration of meiosis I were 0.91 ± 0.01, 8.82 ± 0.06, and 7.93 ± 0.06 h, respectively. The overall rate of cumulus layer expansion was 0.091 ± 0.002 μm/min, and the velocity of expansion peaked during the first 8 h of in vitro maturation (IVM) and then slowed. IVM of oocytes exposed to Nocodazole, a microtubule disrupting agent, and cumulus oocyte complexes (COCs) to 4-methylumbelliferone, a hyaluronan synthesis inhibitor, resulted in a dose-dependent perturbation of morphokinetics, thereby validating the system. The incidence of euploidy following IVM was >90% for both denuded oocytes and intact COCs. No differences were observed between euploid and aneuploid eggs with respect to time to GVBD (0.90 ± 0.22 vs. 0.97 ± 0.19 h), time to PBE (8.89 ± 0.98 vs. 9.10 ± 1.42 h), duration of meiosis I (8.01 ± 0.91 vs. 8.13 ± 1.38 h), and overall rate and kinetics of cumulus expansion (0.089 ± 0.02 vs 0.088 ± 0.03 μm/min) (P > 0.05). These morphokinetic parameters provide novel quantitative and non-invasive metrics for the evaluation of meiotic maturation and cumulus expansion and will enable screening compounds that modulate these processes.

What should be done in terms of fertility preservation for patients with cancer? The French 2021 guidelines

AIM

To provide practice guidelines about fertility preservation (FP) in oncology.

METHODS

We selected 400 articles after a PubMed review of the literature (1987-2019).

RECOMMENDATIONS

Any child, adolescent and adult of reproductive age should be informed about the risk of treatment gonadotoxicity. In women, systematically proposed FP counselling between 15 and 38 years of age in case of treatment including bifunctional alkylating agents, above 6 g/m2 cyclophosphamide equivalent dose (CED), and for radiation doses on the ovaries ≥3 Gy. For postmenarchal patients, oocyte cryopreservation after ovarian stimulation is the first-line FP technique. Ovarian tissue cryopreservation should be discussed as a first-line approach in case of treatment with a high gonadotoxic risk, when chemotherapy has already started and in urgent cases. Ovarian transposition is to be discussed prior to pelvic radiotherapy involving a high risk of premature ovarian failure. For prepubertal girls, ovarian tissue cryopreservation should be proposed in the case of treatment with a high gonadotoxic risk. In pubertal males, sperm cryopreservation must be systematically offered to any male who is to undergo cancer treatment, regardless of toxicity. Testicular tissue cryopreservation must be proposed in males unable to cryopreserve sperm who are to undergo a treatment with intermediate or severe risk of gonadotoxicity. In prepubertal boys, testicular tissue preservation is: - recommended for chemotherapy with a CED ≥7500 mg/m2 or radiotherapy ≥3 Gy on both testicles. - proposed for chemotherapy with a CED ≥5.000 mg/m2 or radiotherapy ≥2 Gy. If several possible strategies, the ultimate choice is made by the patient.

A practical survey of fertility-preservation treatments in the startup phase in Japan

AIM

The actual status of fertility preservation treatments in the startup phase in Japan was investigated as a basis for discussing future directions.

METHODS

This study was conducted as "Research project to promote support of children and parenting 2016" which was supported by Ministry of Health in Japan with the approval of the institutional review board at St. Marianna University. Subjects of the survey were facilities registered with the Japan Society of Obstetrics and Gynecology as fertility preservation facilities, and facilities belonging to the Japan Association of Private Assisted Reproductive Technology Clinics and Laboratories. We provided questionnaires to survey both the medical care system and cases for which fertility preservation was implemented between 2006 and 2016.

RESULTS

Responses were obtained from 68 facilities (of the 64, 59 [92.2%] responded to the questionnaire and 9 clinics cooperated). Many facilities limited the cryopreservation of oocytes and ovaries to patients 40-41 years old and the use of eggs to patients 44-45 years old. In the patient survey, 812 cases of oocyte cryopreservation and 201 cases of ovarian tissue cryopreservation were performed during study period. Breast cancer was the most indicated disease, with oocyte cryopreservation in the late 30s and ovarian tissue cryopreservation in the early 30s. Very few babies were born from fertility preservation, and no live birth cases of ovarian tissue cryopreservation were identified.

CONCLUSIONS

Even from the early days, fertility preservation was implemented according to certain standards in Japan, but was characterized by a large variety of facilities.

Installing oncofertility programs for breast cancer in limited versus optimum resource settings: Empirical data from 39 surveyed centers in Repro-Can-OPEN Study Part I & II

PURPOSE

As a further step to elucidate the actual diverse spectrum of oncofertility practices for breast cancer around the globe, we present and discuss the comparisons of oncofertility practices for breast cancer in limited versus optimum resource settings based on data collected in the Repro-Can-OPEN Study Part I & II.

METHODS

We surveyed 39 oncofertility centers including 14 in limited resource settings from Africa, Asia & Latin America (Repro-Can-OPEN Study Part I), and 25 in optimum resource settings from the United States, Europe, Australia and Japan (Repro-Can-OPEN Study Part II). Survey questions covered the availability of fertility preservation and restoration options offered to young female patients with breast cancer as well as the degree of utilization.

RESULTS

In the Repro-Can-OPEN Study Part I & II, responses for breast cancer and calculated oncofertility scores showed the following characteristics: (1) higher oncofertility scores in optimum resource settings than in limited resource settings especially for established options, (2) frequent utilization of egg freezing, embryo freezing, ovarian tissue freezing, GnRH analogs, and fractionation of chemo- and radiotherapy, (3) promising utilization of oocyte in vitro maturation (IVM), (4) rare utilization of neoadjuvant cytoprotective pharmacotherapy, artificial ovary, and stem cells reproductive technology as they are still in preclinical or early clinical research settings, (5) recognition that technical and ethical concerns should be considered when offering advanced and innovative oncofertility options.

CONCLUSIONS

We presented a plausible oncofertility best practice model to guide oncofertility teams in optimizing care for breast cancer patients in various resource settings.

Twenty-first century oocyte cryopreservation—in vitro maturation of immature oocytes from ovarian tissue cryopreservation in cancer patients: A systematic review

Objectives:

Our review aimed to consolidate the latest update on the application of in vitro maturation among immature oocyte harvest in combination with ovarian tissue cryopreservation known as ovarian tissue oocyte–in vitro maturation.

Methods:

A thorough search for relevant studies was conducted via PubMed, Google Scholar, EMBASE, and clinical.gov databases up to December 2020. The primary outcome was the oocyte maturation rate, which measured the number of immature oocytes (geminal vesicle stage) that progressed to mature oocytes (meiosis II stage) following in vitro maturation. The secondary outcomes were the fertilization rate following intracytoplasmic sperm injection/in vitro fertilization of these oocytes for the embryo cryopreservation cohort. Our review included pre-pubertal girls and women with cancer who underwent ovarian tissue oocyte–in vitro maturation as fertility preservation.

Results:

The primary search identified 207 studies. Twelve manuscripts were selected for inclusion in our review following duplication assessment, title and abstract screening, and full-text evaluation tailored to our inclusion criteria. All the population belonged to a cancer group and underwent concurrent ovarian tissue oocyte–in vitro maturation. A total of 5724 immature oocytes were obtained following ovarian tissue cryopreservation. Approximately 33.84% of the immature oocytes successfully matured via in vitro maturation, which were cryopreserved as oocytes or fertilized as embryos and subsequently stored for future use.

Conclusion:

Our review proposed the potential application of ovarian tissue oocyte–in vitro maturation in increasing the number of mature oocytes. The acceptable improvement in oocyte maturation rate following in vitro maturation indicates that improving oocyte outcomes is an excellent cost-effective strategy for fertility preservation among women with cancer.

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].

Fertility Preservation: How to Preserve Ovarian Function in Children, Adolescents and Adults

Chemotherapy, pelvic radiotherapy and ovarian surgery have known gonadotoxic effects that can lead to endocrine dysfunction, cessation of ovarian endocrine activity and early depletion of the ovarian reserve, causing a risk for future fertility problems, even in children. Important determinants of this risk are the patient’s age and ovarian reserve, type of treatment and dose. When the risk of premature ovarian insufficiency is high, fertility preservation strategies must be offered to the patient. Furthermore, fertility preservation may sometimes be needed in conditions other than cancer, such as in non-malignant diseases or in patients seeking fertility preservation for personal reasons. Oocyte and/or embryo vitrification and ovarian tissue cryopreservation are the two methods currently endorsed by the American Society for Reproductive Medicine, yielding encouraging results in terms of pregnancy and live birth rates. The choice of one technique above the other depends mostly on the age and pubertal status of the patient, and personal and medical circumstances. This review focuses on the available fertility preservation techniques, their appropriateness according to patient age and their efficacy in terms of pregnancy and live birth rates.

In Vitro Maturation of Oocytes Retrieved from Ovarian Tissue: Outcomes from Current Approaches and Future Perspectives

In vitro maturation (IVM) of transvaginally aspirated immature oocytes is an effective and safe assisted reproductive treatment for predicted or high responder patients. Currently, immature oocytes are also being collected from the contralateral ovary during laparoscopy/laparotomy and even ex vivo from the excised ovary or the spent media during ovarian tissue preparation prior to ovarian cortex cryopreservation. The first live births from in vitro-matured ovarian tissue oocytes (OTO-IVM) were reported after monophasic OTO-IVM, showing the ability to achieve mature OTO-IVM oocytes. However, fertilisations rates and further embryological developmental capacity appeared impaired. The introduction of a biphasic IVM, also called capacitation (CAPA)-IVM, has been a significant improvement of the oocytes maturation protocol. However, evidence on OTO-IVM is still scarce and validation of the first results is of utmost importance to confirm reproducibility, including the follow-up of OTO-IVM children. Differences between IVM and OTO-IVM should be well understood to provide realistic expectations to patients.

Case report: two cases of mature oocytes found in prepubertal girls during ovarian tissue cryopreservation

Objective

To report two cases of mature oocytes found in prepubertal girls undergoing ovarian tissue cryopreservation (OTC).

Design

Case report.

Setting

Large tertiary care children’s hospital and a private fertility clinic.

Patient(s)

An 8-year-old prepubertal girl with β-thalassemia and a 2-year-old girl with sickle cell disease who both underwent OTC before bone marrow transplantations.

Intervention(s)

Laparoscopic right oophorectomy was performed in each patient. The ovarian cortical tissue was processed for slow freezing and long-term storage, and all oocytes were subsequently vitrified.

Main Outcome Measure(s)

Oocytes found at the time of OTC processing for fertility preservation.

Result(s)

After a complete right oophorectomy, one mature metaphase II oocyte was discovered on tissue processing for OTC in each patient. Neither patient has yet returned for use of tissue or oocytes.

Conclusion(s)

To our knowledge, this is the first report of mature oocytes found during prepubertal OTC processing. These findings may indicate the need for increased research regarding prepubertal oocyte development and suggest that the technique of examining the media for both mature and immature oocytes at the time of OTC should become more widespread and perhaps recommended in prepubertal patients to optimize fertility preservation methods.

Feasibility of Secondary Follicle Isolation, Culture and Achievement of In-Vitro Oocyte Maturation from Superovulated Ovaries: An Experimental Proof-of-Concept Study Using Mice

Fertility preservation through ovarian stimulation, aiming at cryopreserving mature oocytes or embryos, is sometimes unsuccessful. This clinical situation deserves novel approaches to overcome infertility following cancer treatment in patients facing highly gonadotoxic treatment. In this controlled experimental study, we investigated the feasibility of in-vitro culturing secondary follicles isolated from superovulated ovaries of mice recently treated with gonadotropins. The follicle yields of superovulated ovaries were 45.9% less than in unstimulated controls. Follicles from superovulated ovaries showed faster growth pace during the initial 7 days of culture and secreted more 17β-estradiol by the end of culture vs controls. Parameters reflecting the outcome of follicular development and oocyte maturation competence in vitro were similar between superovulated and control groups, with a similar follicle size at the end of culture and around 70% survival. Nearly half of cultured follicles met the criteria for in-vitro maturation in both groups and approximately 60% of those achieved a mature MII oocyte, similarly in both groups. Over 60% of obtained MII oocytes displayed normal-looking spindle and chromosome configurations, without significant differences between the groups. Using a validated follicle culture system, we demonstrated the feasibility of secondary follicle isolation, in-vitro culture and oocyte maturation with normal spindle and chromosome configurations obtained from superovulated mice ovaries.

Immature Follicular Origins and Disrupted Oocyte Growth Pathways Contribute to Decreased Gamete Quality During Reproductive Juvenescence in Mice

Egg quality dictates fertility outcomes, and although there is a well-documented decline with advanced reproductive age, how it changes during puberty is less understood. Such knowledge is critical, since advances in Assisted Reproductive Technologies are enabling pre- and peri-pubertal patients to preserve fertility in the medical setting. Therefore, we investigated egg quality parameters in a mouse model of the pubertal transition or juvenescence (postnatal day; PND 11-40). Animal weight, vaginal opening, serum inhibin B levels, oocyte yield, oocyte diameter, and zona pellucida thickness increased with age. After PND 15, there was an age-associated ability of oocytes to resume meiosis and reach metaphase of meiosis II (MII) following in vitro maturation (IVM). However, eggs from the younger cohort (PND 16-20) had significantly more chromosome configuration abnormalities relative to the older cohorts and many were at telophase I instead of MII, indicative of a cell cycle delay. Oocytes from the youngest mouse cohorts originated from the smallest antral follicles with the fewest cumulus layers per oocyte, suggesting a more developmentally immature state. RNA Seq analysis of oocytes from mice at distinct ages revealed that the genes involved in cellular growth signaling pathways (PI3K, mTOR, and Hippo) were consistently repressed with meiotic competence, whereas genes involved in cellular communication were upregulated in oocytes with age. Taken together, these data demonstrate that gametes harvested during the pubertal transition have low meiotic maturation potential and derive from immature follicular origins.

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

STUDY QUESTION

What is the reproductive potential following combinations of ovarian stimulation, IVM and ovarian tissue cryopreservation (OTC) in female patients seeking fertility preservation (FP)?

SUMMARY ANSWER

In selected patients, combining different FP procedures is a feasible approach and reproductive outcomes after FP in patients who return to attempt pregnancy are promising.

WHAT IS KNOWN ALREADY

FP is increasingly performed in fertility clinics but an algorithm to select the most suitable FP procedure according to patient characteristics and available timeframe is currently lacking. Vitrification of mature oocytes (OV) and OTC are most commonly performed, although in some clinical scenarios a combination of procedures including IVM, to spread the sources of gametes, may be considered in order to enhance reproductive options for the future.

STUDY DESIGN, SIZE, DURATION

Retrospective, observational study in a university-based, tertiary fertility centre involving all female patients who underwent urgent medical FP between January 2012 and December 2018. Descriptive analysis of various FP procedures, either stand-alone or combined, was performed, and reproductive outcomes of patients who attempted pregnancy in the follow-up period were recorded.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In total, 207 patients underwent medical FP. Patient-tailored strategies and procedures were selected after multidisciplinary discussion. When deemed feasible, FP procedures were combined to cryopreserve different types of reproductive tissue for future use. The main primary outcome measure was the number of mature oocytes. Live birth rates were evaluated in patients who returned for reproductive treatment.

MAIN RESULTS AND THE ROLE OF CHANCE

Among patients seeking FP, 95/207 (46%) had breast cancer, 43/207 (21%) had haematological malignancies and 31/207 (15%) had a gynaecological tumour. Mean ± SD age was 27.0 ± 8.3 years. Eighty-five (41.1%) patients underwent controlled ovarian stimulation (COS), resulting in 10.8 ± 7.1 metaphase II (MII) oocytes for vitrification. Eleven (5.3%) patients had multiple COS cycles. Transvaginal oocyte retrieval for IVM was performed in 17 (8.2%) patients, yielding 9.2 ± 10.1 MII oocytes. Thirty-four (16.4%) patients underwent OTC combined with IVM of oocytes retrieved from ovarian tissue 'ex vivo' (OTO-IVM), yielding 4.0 ± 4.3 MII oocytes in addition to ovarian fragments. Seventeen (8.2%) patients had OTC combined with OTO-IVM and transvaginal retrieval of oocytes for IVM from the contralateral ovary, resulting in 13.5 ± 9.7 MII oocytes. In 13 (6.3%) patients, OTC with OTO-IVM was followed by controlled stimulation of the contralateral ovary, yielding 11.3 ± 6.6 MII oocytes in total. During the timeframe of the study, 31/207 (15%) patients have returned to the fertility clinic with a desire for pregnancy. Of those, 12 (38.7%) patients had preserved ovarian function and underwent ART treatment with fresh oocytes, resulting in nine (75%) livebirth. The remaining 19 (61.3%) patients requested warming of their cryopreserved material because of ovarian insufficiency. Of those, eight (42.1%) patients had a livebirth, of whom three after OTO-IVM. To date, 5/207 patients (2.4%) achieved an ongoing pregnancy or livebirth after spontaneous conception.

LIMITATIONS, REASONS FOR CAUTION

Our FP programme is based on a patient-tailored approach rather than based on an efficiency-driven algorithm. The data presented are descriptive, which precludes firm conclusions.

WIDER IMPLICATIONS OF THE FINDINGS

Combining different FP procedures is likely to enhance the reproductive fitness of patients undergoing gonadotoxic treatment but further follow-up studies are needed to confirm this.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used for this study and the authors have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Live births following fertility preservation using in-vitro maturation of ovarian tissue oocytes

STUDY QUESTION

Can oocytes extracted from excised ovarian tissue and matured in vitro be a useful adjunct for urgent fertility preservation (FP)?

SUMMARY ANSWER

Ovarian tissue oocyte in-vitro maturation (OTO-IVM) in combination with ovarian tissue cryopreservation (OTC) is a valuable adjunct technique for FP.

WHAT IS KNOWN ALREADY

Despite the impressive progress in the field, options for FP for cancer patients are still limited and, depending on the technique, clinical outcome data are still scarce.

STUDY DESIGN, SIZE, DURATION

This was a retrospective cohort study conducted at a university hospital-affiliated fertility clinic between January 2012 and May 2019.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included 77 patients who underwent unilateral oophorectomy for OTC. Cumulus-oocyte complexes (COCs) obtained during ovarian tissue processing were matured in vitro for 28-42 h. Oocytes reaching metaphase II stage were vitrified or inseminated for embryo vitrification.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, 1220 COCs were collected. The mean oocyte maturation rate was 39% ± 23% (SD). There were 64 patients who had vitrification of oocytes (6.7 ± 6.3 oocytes per patient). There were 13 patients who had ICSI of mature oocytes after IVM, with 2.0 ± 2.0 embryos vitrified per patient. Twelve patients have returned to the clinic with a desire for pregnancy. For seven of these, OTO-IVM material was thawed. Two patients had OTO-IVM oocytes warmed, with survival rates of 86% and 60%. After ICSI, six oocytes were fertilised in total, generating three good quality embryos for transfer, leading to a healthy live birth for one patient. In five patients, for whom a mean of 2.0 ± 0.8 (SD) embryos had been vitrified, seven embryos were warmed in total: one embryo did not survive the warming process; two tested genetically unsuitable for transfer; and four were transferred in separate cycles to three different patients, resulting in two healthy babies. In this small series, the live birth rate per patient after OTO-IVM, ICSI and embryo transfer was 43%.

LIMITATIONS, REASONS FOR CAUTION

The retrospective study design and the limited sample size should be considered when interpreting results.

WIDER IMPLICATIONS OF THE FINDINGS

The results of the study illustrate the added value of OTO-IVM in combination with OTC. We report the first live birth following the use of this appended technique combined with oocyte vitrification.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used for this study. M.D.V. reports honoraria for lectures in the last 2 years from MSD and Ferring, outside the submitted work, as well as grant support from MSD. The other authors have nothing to declare.

TRIAL REGISTRATION NUMBER

N/A.

Surviving cancer or future motherhood? Both are possible: an Ewing sarcoma case in an 8-year-old girl

Ewing's sarcoma is an aggressive tumour, common in paediatric age, in which treatment often implies a decrease in reproductive potential. We describe a case of a woman who had a lumbar Ewing's Sarcoma in 1991, at the age of 8. She was submitted to extended tumourectomy, chemotherapy and local radiotherapy without preservation techniques. In adult life, and after two in vitro fertilization (IVF) reproductive cycles without success, she spontaneously conceived at the age of 32. After an uneventful pregnancy, she delivered a healthy child by caesarean section. This is a rare successful case of a spontaneous and uneventful pregnancy without previous preservation techniques. In the last 30 years, there has been significant development in this area, and currently, there are solutions for these patients, including in prepubertal age.

Low feasibility of in vitro matured oocytes originating from cumulus complexes found during ovarian tissue preparation at the moment of gender confirmation surgery and during testosterone treatment for fertility preservation in transgender men

OBJECTIVE

To study the feasibility of in vitro maturation of ovarian tissue oocytes for fertility preservation in transgender men on testosterone treatment.

DESIGN

Cross-sectional study SETTING: University hospital PATIENT(S): Eighty-three transgender men enrolled from November 2015 to January 2019 INTERVENTION(S): In vitro maturation of cumulus-oocyte complexes (COCs) harvested at the time of gender confirmation surgery, and fertilization through intracytoplasmic sperm injection.

MAIN OUTCOME MEASURE(S)

In vitro maturation, fertilization, and blastulation rates; comparison of morphokinetics with vitrified-warmed oocytes; and analysis of the genetic profiles of embryos.

SECONDARY OUTCOMES

association between serum hormone levels; COCs' morphologic characteristics, and vitrification rate.

RESULT(S)

All participants were on testosterone treatment for a median of 83 (64[Quartile 1]; 113.2[Quartile 2]) weeks. A total of 1,903 COCs (mean per participant, 23 ± 15.8) were collected. The in vitro maturation rate was 23.8%, vitrification rate was 21.5%, and survival rate after warming was 72.6% (n = 151). Intracytoplasmic sperm injection was performed in 139 oocytes. The rate of normal fertilized oocytes was 34.5%, and 25 (52.1%) embryos reached day 3. One blastocyst was achieved on day 5. Aberrant cleavage patterns and early embryo arrest were observed in 22 (45.8%) and 44 (91.7%) zygotes, respectively. Compared with vitrified-warmed donor oocytes, a delay was observed in pronuclei disappearance, t2 (time to reach 2 cell stage) timings, and CC1 (the duration of the 1st cell cycle) and SS3 (synchronization of cleavage pattern (calculated as t8-t5) time intervals. A normal genetic pattern was seen in 42% embryos. The proportion of vitrified oocytes was negatively associated with progesterone (odds ratio, 0.76) and positively associated with antimüllerian hormone serum levels (odds ratio, 1.23). The highest vitrification rate was achieved by the morphologic characteristic 344 at day 0 and by 433 at day 2.

CONCLUSION(S)

Ovarian tissue oocytes matured in vitro show low developmental capacity in transgender men, when collected under testosterone treatment.

Impact of Maturation and Vitrification Time of Human GV Oocytes on the Metaphase Plate Configuration

The combination of in vitro maturation (IVM) techniques and oocyte vitrification (OV) could increase the number of useful oocytes in different types of patients. IVM and subsequent OV is the most widely used clinical strategy. Would the results improve if we reverse the order of the techniques? Here, we evaluated survival, in vitro maturation, time to extrude the first polar body (PB), and the metaphase plate configuration of human prophase I (GV) oocytes before or after their vitrification. Specific, 195 GV oocytes from 104 patients subjected to controlled ovarian stimulation cycles were included. We stablished three experimental groups: GV oocytes vitrified and IVM (Group GV-Vit), GV oocytes IVM and vitrified at MII stage (Group MII-Vit), and GV oocytes IVM (Group not-Vit). All of them were in vitro matured for a maximum of 48 h and fixed to study the metaphase plate by confocal microscopy. According to our results, the vitrification of immature oocytes and their subsequent maturation presented similar survival, maturation, and metaphase plate conformation rates, but a significantly higher percentage of normal spindle than the standard strategy. Additionally, the extension of IVM time to 48 h did not seem to negatively affect the oocyte metaphase plate configuration.

Installing oncofertility programs for common cancers in optimum resource settings (Repro-Can-OPEN Study Part II): a committee opinion

PURPOSE

The main objective of Repro-Can-OPEN Study Part 2 is to learn more about oncofertility practices in optimum resource settings to provide a roadmap to establish oncofertility best practice models.

METHODS

As an extrapolation for oncofertility best practice models in optimum resource settings, we surveyed 25 leading and well-resourced oncofertility centers and institutions from the USA, Europe, Australia, and Japan. The survey included questions on the availability and degree of utilization of fertility preservation options in case of childhood cancer, breast cancer, and blood cancer.

RESULTS

All surveyed centers responded to all questions. Responses and their calculated oncofertility scores showed three major characteristics of oncofertility practice in optimum resource settings: (1) strong utilization of sperm freezing, egg freezing, embryo freezing, ovarian tissue freezing, gonadal shielding, and fractionation of chemo- and radiotherapy; (2) promising utilization of GnRH analogs, oophoropexy, testicular tissue freezing, and oocyte in vitro maturation (IVM); and (3) rare utilization of neoadjuvant cytoprotective pharmacotherapy, artificial ovary, in vitro spermatogenesis, and stem cell reproductive technology as they are still in preclinical or early clinical research settings. Proper technical and ethical concerns should be considered when offering advanced and experimental oncofertility options to patients.

CONCLUSIONS

Our Repro-Can-OPEN Study Part 2 proposed installing specific oncofertility programs for common cancers in optimum resource settings as an extrapolation for best practice models. This will provide efficient oncofertility edification and modeling to oncofertility teams and related healthcare providers around the globe and help them offer the best care possible to their patients.

Prospects of Rescuing Young Eggs for Oncofertility

Childhood cancer patients undergoing cancer therapy can be rendered infertile during adulthood. With more girls surviving cancer, fertility preservation in young cancer patients is a major clinical challenge. Advances in egg culture may offer benefits for the fertility of these patients in the future.

Fertility preservation options for transgender and gender-nonconforming individuals

PURPOSE OF REVIEW

To provide an overview of the current state of knowledge of fertility risks of gender-affirming therapy, review fertility preservation options for transgender individuals and ways to minimize gender dysphoria during fertility treatment, and identify gaps in knowledge.

RECENT FINDINGS

Recent studies have corroborated older data that gender-affirming hormone therapy creates histopathological changes in the gonads; however, the newer data suggests that some function of the gametes may be preserved. One study in transgender men reported successful in-vitro maturation of testosterone-exposed oocytes with normal spindle structures, and recent studies in transgender women reveal early spermatogenesis in estradiol-exposed testes and some recovery of semen parameters following cessation of hormones. Particular attention has recently been given to fertility preservation in transgender adolescents, revealing unmet informational needs in this population and very few are actually pursuing fertility preservation, even with counseling.

SUMMARY

There is currently a paucity of data on the fertility effects of gender-affirming hormones, necessitating fertility preservation counseling prior to initiation of therapy. Several modifications can be made to fertility preservation protocols and procedures to decrease gender dysphoria or distress in transgender individuals, but outcome data is still lacking. Achieving high-quality data collection will likely require cooperation across multiple institutions.

In-vitro maturation of oocytes recovered during cryopreservation of pre-pubertal girls undergoing fertility preservation

RESEARCH QUESTION

In-vitro maturation (IVM) of oocytes recovered during ovarian tissue cryopreservation (OTC) is often practised, although it is still considered experimental. To date, only a few studies have examined the success of this maturation process in pre-menarche girls. The aim of this study was to examine the outcomes of IVM of oocytes recovered during OTC in pre-menarche patients scheduled for onco-therapy.

DESIGN

A retrospective cohort study in a tertiary university-affiliated hospital. A total of 93 patients aged 0-25 years who underwent OTC as part of onco-fertility preservation between 2007 and 2019 were included in the study. Oocytes were recovered from the medium after OTC and matured over 48 h. Oocyte development and maturation rate were recorded and compared between different age groups.

RESULTS

Patient's age was not correlated linearly with the total number of mature oocytes R = 0.2. The absolute maturation rate in post-menarche and pre-menarche patients differed significantly (38.0% versus 25.3%, respectively; P > 0.001), whereas the degeneration rate of the oocytes did not (39.8% versus 33.5%; P = 0.167). The pre-menarche group had significantly lower mean number of metaphase II oocytes compared with the post-menarche group (2.8 [±2.3] versus 5.6 [±4.6]; P = 0.01; 95% CI -4.62 to -0.46). Oocytes recovered from patients aged 1-5 years demonstrated low maturation rate.

CONCLUSIONS

Oocytes recovered from pre-menarche girls, and especially those younger than the age of 5 years who undergo fertility preservation, have a lower chance of reaching maturity in IVM compared with older women. This may indicate a need for alternative methods for preserving fertility in these young patients.

In vitro maturation of immature oocytes from ovarian tissue prior to shipment to a cryobank

PURPOSE

Female fertility preservation prior to gonadotoxic therapies can be achieved by the cryopreservation of ovarian cortical tissue. Immature oocytes may be recovered during the preparation, matured in vitro and lead to live births, thereby providing an additional option for fertility preservation. The purpose of this study was to test the feasibility of this approach in a setting with unilateral biopsy of a small piece of ovarian tissue and minimal tissue preparation prior to shipment to an external cryobank.

METHODS

A prospective observational clinical study in an academic center was performed from January 2018 through December 2019. Ovarian tissue was obtained laparoscopically. Immature oocytes were recovered by minimal preparation of the tissue before shipment to an external cryobank for cryopreservation. In vitro maturation was performed on recovered immature oocytes.

RESULTS

Twelve patients were enrolled. Immature oocytes could be recovered for all. The maturation rate was 38.9% (n = 14/36). Metaphase II (MII) were either directly used for intracytoplasmic sperm injection (ICSI) with a fertilization rate of 66.6% (n = 4/6) or vitrified (n = 8). PNs were cryopreserved (n = 4). Vitrified MII were warmed with a post-warming vitality rate of 75.0% (n = 3/4) and used for ICSI with a fertilization rate of 33.3% (n = 1/3).

CONCLUSIONS

Immature oocytes can be successfully retrieved from ovarian tissue through minimal tissue preparation prior to shipment to a cryobank, matured in vitro, fertilized and cryopreserved for potential future fertility treatments. The total number of oocytes available for fertility preservation can be increased even without controlled ovarian stimulation in a situation where only ovarian biopsy for cryopreservation is performed.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS), DRKS00013170. Registered 11 December 2017, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00013170 .

Germinal stage vitrification is superior to MII stage vitrification in prepubertal mouse oocytes

This study investigated if in vitro maturation (IVM) before or after vitrification would be more successful for prepubertal oocytes. To mimic prepubertal conditions in an experimental setup, oocytes were collected from healthy 14, 21 and 28day old Swiss albino mice. The germinal vesicle (GV) stage oocytes and in vitro matured MII oocytes were subjected to vitrification-warming. Both structural (meiotic spindle morphology, mitochondrial integrity, cortical granules) and functional (sperm zona binding, fertilization) characteristics were assessed in oocytes after warming. This study demonstrated that IVM was more detrimental to prepubertal oocytes than to young adults. Further, vitrification of the IVM oocytes resulted in an increase in the number of abnormal meiotic spindles, a change in the cortical distribution pattern, a reduction in sperm zona binding and the fertilization rate. Importantly, oocyte integrity was better when prepubertal oocytes were vitrified before, rather than after, IVM. The above observations support GV stage vitrification for prepubertal oocytes requiring fertility preservation. Understanding the mechanisms behind the differing outcomes for oocytes from immature females will help in refining current protocol, thereby retaining the oocytes' maximum structural and functional integrity Further investigation is necessary to determine whether human prepubertal oocytes also behave in a similar way. It is to be noted here, with great emphasis, that a major limitation of this study is that the oocytes' abilities were tested only until fertilisation, as a consequence of which the study cannot reveal the developmental potentials of the embryos beyond fertilisation.

Improving the maturation rate of human oocytes collected ex vivo during the cryopreservation of ovarian tissue

PURPOSE

The aim of the present study was to improve the in vitro maturation (IVM) procedure using oocytes from surplus ovarian tissue after fertility preservation.

METHODS

Twenty-five patients aged 17-37 years were included in the study. Maturation was compared between oocytes collected in HEPES-buffered medium or saline, and we determined whether transport on ice prior to oocyte collection affected maturation. Two different IVM media were used that were supplemented with and without recombinant human midkine. Mature oocytes were assessed for aneuploidy using next-generation sequencing (NGS).

RESULTS

On average, 36 immature oocytes were collected from each patient (range 7-90, N = 895). Oocytes recovered from HEPES-buffered medium matured at a higher rate than oocytes recovered from saline (36% vs 26%, p < 0.01). Ovarian transportation on ice prior to the procedure negatively affected maturation compared with non-transported samples (42% vs 27%, p < 0.01). The addition of midkine improved maturation rate (34% vs 27%, p < 0.05). On average, 11 MII oocytes were obtained per patient (range 1-30). NGS of 53 MII oocytes and their first polar bodies indicated that 64% were euploid.

CONCLUSIONS

The study demonstrated unexpectedly high number of immature oocytes collected from surplus ovarian tissue without any stimulation. The overall MII rate was one in three, resulting in a total number of MII oocytes that was similar to the number obtained after ovarian stimulation. If these MII oocytes prove suitable for IVF, they will provide a substantial improvement in fertility preservation for patients and advance IVM as an interesting platform for further improvements in assisted reproduction.

Ovarian stimulation is a safe and effective fertility preservation option in the adolescent and young adult population

PURPOSE

The aim of this study is to describe the multidisciplinary approach and controlled ovarian hyperstimulation (COH) outcomes in adolescent and young adult (AYA) patients (ages 13-21) who underwent oocyte cryopreservation for fertility preservation (FP).

METHODS

Multi-site retrospective cohort was performed from 2007 to 2018 at Northwestern University and Michigan University. Data were analyzed by chi-square test, t-test, and logistic regression.

RESULTS

Forty-one patients began COH of which 38 patients successfully underwent oocyte retrieval, with mature oocytes obtained and cryopreserved without any adverse outcomes. To treat this group of patients, we use a multidisciplinary approach with a patient navigator. When dividing patients by ages 13-17 vs. 18-21, the median doses of FSH used were 2325 and 2038 IU, the median number of mature oocytes retrieved were 10 and 10, and median number frozen oocytes were 11 and 13, respectively. Median days of stimulation were 10 for both groups. There was no statistical difference in BMI, AMH, peak E₂, FSH dosage, days stimulated, total oocytes retrieved, mature oocytes retrieved, and oocytes frozen between the two groups. Three patients were canceled for poor response.

CONCLUSION

COH with oocyte cryopreservation is a feasible FP option for AYAs who may not have other alternatives when appropriate precautions are taken, such as proper counseling and having a support team. These promising outcomes correspond to similar findings of recent small case series, providing hope for these patients to have genetically related offspring in the future.

Preserving fertility in female patients with hematological malignancies: a multidisciplinary oncofertility approach

Oncofertility is a new interdisciplinary field at the intersection of oncology and reproductive medicine that expands fertility options for young cancer patients. The most common forms of hematological malignancies that occur in girls and young women and therefore necessitate oncofertility care are acute lymphocytic leukemia, acute myeloid leukemia, non-Hodgkin's lymphoma, and Hodgkin's lymphoma. Aggressive gonadotoxic anticancer regimens including alkylating chemotherapy and total body irradiation are used often in treating girls and young women with hematological malignancies. The risks of gonadotoxicity and subsequent iatrogenic premature ovarian insufficiency and fertility loss depend mainly on the type and stage of the disease, dose of anticancer therapy as well as the age of the patient at the beginning of treatment. To avoid or at least mitigate the devastating complications of anticancer therapy-induced gonadotoxicity, effective and comprehensive strategies that integrate different options for preserving and restoring fertility ranging from established to experimental strategies should be offered before, during, and after chemotherapy or radiotherapy. A multidisciplinary approach that involves strong coordination and collaboration between hemato-oncologists, gynecologists, reproductive biologists, research scientists, and patient navigators is essential to guarantee high standard of care.

Fertility and hormone preservation and restoration for female children and adolescents receiving gonadotoxic cancer treatments: A systematic review

BACKGROUND/PURPOSE

The purpose of this systematic review by the American Pediatric Surgical Cancer Committee was to summarize evidence from the current medical literature regarding fertility restoration and hormone replacement for female children and adolescents treated with gonadotoxic treatments.

METHODS

Using PRISMA guidelines, questions were addressed by searching Medline, Cochrane, Embase Central and National clearing house databases using relevant search terms. Eligible studies included those that addressed ovarian tissue cryopreservation (OTC), oocyte harvest, ovarian transposition, and ovarian tissue auto-transplantation for females under the age of 20. Four reviewers independently screened studies for eligibility, extracted data and assessed the risk of bias. Study outcomes were summarized in a narrative synthesis.

RESULTS

Two thousand two hundred seventy-six studies were identified by database search and manual review and 2185 were eliminated based on defined exclusion criteria. Ninety-one studies served as the basis for the systematic review. There were 1019 patients who underwent OTC with ages ranging from 0.4 to 20.4 years old, with 298 under the age of 13. Twenty patients aged 13-20 years old underwent successful oocyte harvest. Thirty-seven children underwent ovarian transposition as a means of fertility preservation. Eighteen patients underwent auto-transplantation of thawed ovarian cortical tissue that was harvested before the age of 21 years resulting in 10 live births.

CONCLUSIONS

Clinically accepted and experimental fertility preservation options such as OTC, oocyte cryopreservation, and ovarian transposition are available to females aged 20 years and younger who are at risk for premature ovarian insufficiency and infertility due to gonadotoxic treatments. There is a large cohort of pediatric-aged patients, with a wide variety of diagnoses and treatments, who have undergone fertility preservation. Currently, fertility and hormone restoration experience for patients who were 20- years of age or younger at the time of fertility preservation remains limited.

LEVEL OF EVIDENCE

IV.

Fertility preservation for transgender adolescents and young adults: a systematic review

BACKGROUND

Many transgender individuals choose to undergo gender-affirming hormone treatment (GAHT) and/or sex reassignment surgery (SRS) to alleviate the distress that is associated with gender dysphoria. Although these treatment options often succeed in alleviating such symptoms, they can also negatively impact future reproductive potential.

OBJECTIVE AND RATIONALE

The purpose of this systematic review was to synthesize the available psychosocial and medical literature on fertility preservation (FP) for transgender adolescents and young adults (TAYAs), to identify gaps in the current research and provide suggestions for future research directions.

SEARCH METHODS

A systematic review of English peer-reviewed papers published from 2001 onwards, using the preferred reporting items for systematic reviews and meta-analyses protocols (PRISMA-P) guidelines, was conducted. Four journal databases (Ovid MEDLINE, PubMed Medline, Ovid Embase and Ovid PsychINFO) were used to identify all relevant studies exploring psychosocial or medical aspects of FP in TAYAs. The search strategy used a combination of subject headings and generic terms related to the study topic and population. Bibliographies of the selected articles were also hand searched and cross-checked to ensure comprehensive coverage. All selected papers were independently reviewed by the co-authors. Characteristics of the studies, objectives and key findings were extracted, and a systematic review was conducted.

OUTCOMES

Included in the study were 19 psychosocial-based research papers and 21 medical-based research papers that explore fertility-related aspects specific for this population. Key psychosocial themes included the desire to have children for TAYAs; FP discussions, counselling and referrals provided by healthcare providers (HCPs); FP utilization; the attitudes, knowledge and beliefs of TAYAs, HCPs and the parents/guardians of TAYAs; and barriers to accessing FP. Key medical themes included fertility-related effects of GAHT, FP options and outcomes. From a synthesis of the literature, we conclude that there are many barriers preventing TAYAs from pursuing FP, including a lack of awareness of FP options, high costs, invasiveness of the available procedures and the potential psychological impact of the FP process. The available medical data on the reproductive effects of GAHT are diverse, and while detrimental effects are anticipated, the extent to which these effects are reversible is unknown.

WIDER IMPLICATIONS

FP counselling should begin as early as possible as a standard of care before GAHT to allow time for informed decisions. The current lack of high-quality medical data specific to FP counselling practice for this population means there is a reliance on expert opinion and extrapolation from studies in the cisgender population. Future research should include large-scale cohort studies (preferably multi-centered), longitudinal studies of TAYAs across the FP process, qualitative studies of the parents/guardians of TAYAs and studies evaluating the effectiveness of different strategies to improve the attitudes, knowledge and beliefs of HCPs.

Development of Ovarian Tissue Autograft to Restore Ovarian Function: Protocol for a French Multicenter Cohort Study

Background

Sterility is a major late effect of radiotherapy and chemotherapy treatments. Iatrogenic sterility is often permanent and greatly impacts long-term quality of life. Ovarian tissue cryopreservation (OTC) performed before gonadotoxic treatments with subsequent autograft is a method of fertility preservation available for girls and women. Its application in prepubertal girls is of particular value as it is the only possible approach in this patient group. In addition, it does not require a delay in cancer therapy and no ovarian stimulation is needed.

Objective

The primary aim of this protocol is to help increase the implementation of ovarian tissue autografting in France. Knowledge is still lacking regarding the efficacy of ovarian transplantation in restoring ovarian function and regarding the safety of this procedure, especially the risk of cancer cell reseeding in certain types of cancer. A secondary aim of this study is to generate data to improve our understanding of these two essential aspects.

Methods

The DATOR (Development of Ovarian Tissue Autograft in Order to Restore Ovarian Function) study is ongoing in 17 university hospitals. The DATOR protocol includes the autograft of ovarian cortex fragments. Candidates are identified from an observational prospective cohort (called the Prospective Cohort of Patients Candidates for Ovarian Tissue Autograft [PERIDATOR]) of patients who have undergone OTC. Enrollment in the study is initiated at the patient’s request and must be validated by the center’s multidisciplinary team and by the study steering committee. The DATOR study begins with a total medical checkup. Ovarian tissue qualification and residual disease detection, if required, are performed.

Results

The study is ongoing. Currently, 38 patients have provided informed consent and have been entered into the DATOR study. Graft has been performed for 34 of these patients. An interim analysis was conducted on the first 25 patients for whom the period of at least 1 year posttransplantation was achieved. Out of these 25 patients, 11 women succeeded in becoming pregnant (pregnancy rate=44% [11/25]; delivery rate=40% [10/25]). Among these, 6 women conceived twice, and 1 pregnancy led to a miscarriage.

Conclusions

Our preliminary analysis appears to be coherent with the accumulating body of evidence indicating the potential utility of ovarian tissue autograft for patients with premature ovarian failure. All these elements justify the pursuit of our study.

Trial Registration

ClinicalTrials.gov NCT02846064; https://clinicaltrials.gov/ct2/show/NCT02846064

International Registered Report Identifier (IRRID)

DERR1-10.2196/12944

Vitrification has detrimental effects on maturation, viability, and subcellular quality of oocytes post IVM in cancerous women: An experimental study

Background

In vitro maturation (IVM) of immature oocytes retrieved from ovarian tissue has been considered as a valuable approach for fertility preservation in cancerous patients.

Objective

To evaluate the efficacy of vitrification on oocyte maturation, survival rates, as well as the subcellular oocyte quality post IVM.

Materials and Methods

The ovarian cortexes from 19 women with cervix and uterine malignancy aged 21-39 yr were collected. Cumulus-oocyte complexes were aspirated from all visible antral follicles. 102 immature oocytes were collected, and 43 oocytes were detected appropriately for IVM (control group). Also, 59 immature oocytes were vitrified, then matured in vitro (IVM) in two groups: with Growth/differentiation factor 9 (GDF9) (group 1) and without GDF9 (group 2) supplementation. Rates of oocytes viability, maturation, and survival along with meiotic spindle visualization and zona pellucida birefringence were assessed with Polyscope.

Results

The rate of maturation was significantly higher in controls (55.8%) compared to the other groups. Maturation rate was 23.3% in oocytes cultured in IVM medium enriched with GDF9, and 27.6% in those cultured in IVM medium lacking GDF9 (p = 0.86). Also, the meiotic spindle was present in 74.4% of control oocytes which was significantly higher than the other groups. The proportion of high zona pellucida birefringence was higher in the controls when compared with group 1 (51.2% vs. 23.3%, respectively, p = 0.04).

Conclusion

Vitrification had a detrimental effect on oocyte maturation, viability as well as the subcellular quality of the oocytes after IVM in cancerous women.

Biphasic in vitro maturation (CAPA-IVM) specifically improves the developmental capacity of oocytes from small antral follicles

PURPOSE

To investigate the effectiveness of a biphasic IVM culture strategy at improving IVM outcomes in oocytes from small follicles (< 6 mm) compared with routine Standard IVM in patients with polycystic ovaries.

METHODS

This prospective pilot study was performed in 40 women with polycystic ovaries whose oocytes were randomized to two IVM culture methods. Patients received a total stimulation dose of 450 IU rFSH. Cumulus-oocyte complexes (COCs) from follicles < 6 mm and ≥ 6 mm were retrieved and cultured separately in either a prematuration medium with c-type natriuretic peptide followed by IVM (CAPA-IVM), or STD-IVM. Primary outcomes were maturation rate, embryo quality, and the number of vitrified day 3 embryos per patient.

RESULTS

Use of the CAPA-IVM system led to a significant improvement in oocyte maturation (p < 0.05), to a doubling in percentage of good and top-quality day 3 embryos per COC, and to an increased number of vitrified day 3 embryos (p < 0.001), compared to STD IVM. Oocytes from follicles < 6 mm benefited most from CAPA-IVM, showing a significant increase in the amount of good and top-quality embryos compared to STD IVM. CAPA-IVM yielded significantly (p < 0.0001) less GV-arrested oocytes and larger oocyte diameters (p < 0.05) than STD IVM.

CONCLUSIONS

CAPA-IVM brings significant improvements in maturation and embryological outcomes, most notably to oocytes from small antral follicles (< 6 mm), which can be easily retrieved from patients with a minimal ovarian stimulation. The study demonstrates the robustness and transferability of the CAPA-IVM method across laboratories and populations.

Role of stem cells in fertility preservation: current insights

While improvements made in the field of cancer therapy allow high survival rates, gonadotoxicity of chemo- and radiotherapy can lead to infertility in male and female pre- and postpubertal patients. Clinical options to preserve fertility before starting gonadotoxic therapies by cryopreserving sperm or oocytes for future use with assisted reproductive technology (ART) are now applied worldwide. Cryopreservation of pre- and postpubertal ovarian tissue containing primordial follicles, though still considered experimental, has already led to the birth of healthy babies after autotransplantation and is performed in an increasing number of centers. For prepubertal boys who do not produce gametes ready for fertilization, cryopreservation of immature testicular tissue (ITT) containing spermatogonial stem cells may be proposed as an experimental strategy with the aim of restoring fertility. Based on achievements in nonhuman primates, autotransplantation of ITT or testicular cell suspensions appears promising to restore fertility of young cancer survivors. So far, whether in two- or three-dimensional culture systems, in vitro maturation of immature male and female gonadal cells or tissue has not demonstrated a capacity to produce safe gametes for ART. Recently, primordial germ cells have been generated from embryonic and induced pluripotent stem cells, but further investigations regarding efficiency and safety are needed. Transplantation of mesenchymal stem cells to improve the vascularization of gonadal tissue grafts, increase the colonization of transplanted cells, and restore the damaged somatic compartment could overcome the current limitations encountered with transplantation.

In vitro maturation rates in young premenarche patients

OBJECTIVE

To evaluate in vitro maturation (IVM) efficacy and oocyte retrieval rates after ovarian tissue cryopreservation in young premenarche girls facing chemo- and radiotherapy.

DESIGN

A retrospective cohort study.

SETTING

University-affiliated tertiary medical center.

PATIENT(S)

A total of 84 chemotherapy-naïve patients ages 0-18 years referred for fertility preservation between 2004 and 2017: 33 premenarche and 51 postmenarche patients.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

IVM in the pre- and postmenarche groups and in the subgroups of very young (up to age 5 years) and older (5-10 years) premenarche girls.

RESULTS

The number of oocytes retrieved did not significantly differ between the postmenarche and premenarche groups (10.8 ± 8.5 and 8.1 ± 6.8, respectively). However, the overall IVM rate was significantly higher in the postmenarche group (28.2% vs. 15.5%, respectively; odds ratio = 0.47). A separate analysis for patients up to 5 years of age demonstrated significantly lower oocyte yield compared with the older (5-10 years) premenarche girls (4.7 ± 5.2 vs.10.3 ± 7.0 oocytes, respectively) and much lower IVM rates (4.9% and 18.2%, respectively). Correlation of age with number of retrieved and matured oocytes showed a positive significant correlation (r = 0.45 and r = 0.64, respectively).

CONCLUSIONS

IVM performed after ovarian tissue cryopreservation in premenarche girls and specifically in very young girls (4 years and younger) yields substantially decreased maturation rates compared with postmenarche patients, raising a question as to the utility of current IVM technique in this age group. Further studies are required to assess modification of the IVM technique for young girls.