The immature human ovary shows loss of abnormal follicles and increasing follicle developmental competence through childhood and adolescence

The latest reports and treatment methods on polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is an increasingly recognized endocrine disorder. The pathogenesis is not fully known. Polycystic ovary syndrome is still difficult to diagnose correctly, despite simple diagnostic criteria. The aim of the study is to review the current knowledge about PCOS and treatment options for patients with the disease. To explore this topic, publications were reviewed and conclusions drawn from them. The incidence of hyperandrogenism in a patient with PCOS may be as high as 60-80%. Increased androgen levels affect ovulation and menstruation, and also result in hirsutism and acne. Additionally, patients have problems with proper glucose tolerance (insulin resistance), type 2 diabetes, hypertension, cardiovascular diseases and metabolic syndrome. PCOS results in various symptoms in patients.

The latest treatment methods were analysed. A standard review of publications in the field of diagnosis and treatment of PCOS, IR and hyperandrogenism was used.

Lifestyle, especially diet, deserves special attention due to its ease of use. Sleep quality, physical activity and stress reduction are also important. Diet should be the treatment of first choice. Only if dietary intervention does not bring results, the doctor considers pharmacotherapy. Recently, acupuncture and herbal medicine, vagus nerve stimulation have been used in the treatment of PCOS and regulation of hormone levels. Patients are given supplementation to improve the quality of functioning, but it must be remembered that inappropriate doses or too long use may result in a toxic effect opposite to the therapeutic one.

Appropriate diet, physical activity - lifestyle changes are crucial in the treatment of PCOS. Supplementation and pharmaceuticals support treatment. It is mandatory to examine these environmental and lifestyle factors as they not only contribute to the occurrence of the disease but also influence its progression.

Synthetic human gonadal tissues for toxicology

The process of mammalian reproduction involves the development of fertile germ cells in the testis and ovary, supported by the surrounders. Fertilization leads to embryo development and ultimately the birth of offspring inheriting parental genome information. Any disruption in this process can result in disorders such as infertility and cancer. Chemical toxicity affecting the reproductive system and embryogenesis can impact birth rates, overall health, and fertility, highlighting the need for animal toxicity studies during drug development. However, the translation of animal data to human health remains challenging due to interspecies differences. In vitro culture systems offer a promising solution to bridge this gap, allowing the study of mammalian cells in an environment that mimics the physiology of the human body. Current advances on in vitro culture systems, such as organoids, enable the development of biomaterials that recapitulate the physiological state of reproductive organs. Application of these technologies to human gonadal cells would provide effective tools for drug screening and toxicity testing, and these models would be a powerful tool to study reproductive biology and pathology. This review focuses on the 2D/3D culture systems of human primary testicular and ovarian cells, highlighting the novel approaches for in vitro study of human reproductive toxicology, specifically in the context of testis and ovary.

Fertility Assessment after Ovarian Transposition in Children and Young Women Treated for a Malignant Tumor

Ovarian transposition (OT) has been proposed as a protective measure against radiation-induced damage to ovarian function and fertility. Despite its historical use, limited research has focused on evaluating endocrine and exocrine ovarian function after OT performed in adolescents and young adults (AYAs) before or during puberty. The purpose of our study was to investigate the fertility, pubertal development, and ovarian function of women with a previous history of OT during childhood, adolescence or young adulthood. In an observational bicentric retrospective study, we included 32 young female cancer patients who underwent OT before the age of 26 between 1990 and 2015 at Lyon Léon Bérard Cancer Center or Nancy University Hospital. The mean age at the time of OT was 15.6 years with a cancer diagnosis at 15 ± 4.8 years. Among the 10 women attempting pregnancy post-treatment, 60% achieved successful pregnancies. After a mean follow-up of 9.6 ± 7 years, 74% (17 out of 23) of women recovered spontaneous menstrual cycles (seven out of eight evaluable women with OT before or during puberty). Notably, 35% of women who did not attempt pregnancy demonstrated adequate ovarian reserve. Ovarian reserve and function recovery were influenced by the specific chemotherapy received. Importantly, our findings suggest that OT's effectiveness on ovarian activity resumption does not significantly differ when performed before or during puberty compared to pubertal stages. This study contributes valuable insights into the long-term reproductive outcomes of young women undergoing OT, emphasizing its potential efficacy in preserving ovarian function and fertility across different developmental stages.

Neurotrophin-4 promotes in vitro development and maturation of human secondary follicles yielding metaphase II oocytes and successful blastocyst formation

STUDY QUESTION

Does a matrix-free culture system supplemented with neurotrophic factor 4 (NT4) improve human in vitro follicular development and meiotic maturation, ultimately resulting in fertilizable oocytes?

SUMMARY ANSWER

NT4 supplementation of in vitro culture significantly enhances the growth, steroid hormone production, and maturity potential of human secondary follicles derived from fresh ovarian medulla (from post- and pre-pubertal patients), thereby yielding fertilizable oocytes.

WHAT IS KNOWN ALREADY

Reconstituting folliculogenesis in vitro is of paramount importance in the realms of fertility preservation, reproductive biology research, and reproductive toxicity assessments. However, the efficiency of in vitro culture systems remains suboptimal, as the attainment of fertilizable oocytes from in vitro growth (IVG) of human follicles remains unachieved, with the data being particularly scant regarding follicles from prepubertal girls. We have previously found that mouse oocytes from secondary follicles derived from IVG are deficient in neuroendocrine regulation. NT4 and its corresponding receptor have been identified in human follicles. Significantly, the addition of NT4 during the IVG process markedly enhances both follicle growth and oocyte maturation rates in mice.

STUDY DESIGN SIZE DURATION

Fresh medulla tissue obtained during tissue preparation for ovarian tissue cryopreservation (OTC) were collected from 10 patients aged from 6 to 21 years old, all of whom had undergone unilateral oophorectomy as a means of fertility preservation. Isolated secondary follicles were individually cultured in vitro with or without NT4 in a matrix-free system.

PARTICIPANTS/MATERIALS SETTING METHODS

Secondary follicles, extracted via enzymatic digestion and mechanical disruption from each patient, were randomly allocated to either a control group or an NT4-supplemented group (100 ng/ml), followed by individual culture on an ultra-low attachment plate. Follicle growth and viability were assessed by microscopy. Levels of anti-Müllerian hormone (AMH), estradiol, and progesterone in the medium were quantified. An oocyte-specific marker was identified using confocal fluorescence microscopy following DEAD box polypeptide 4 (DDX4) staining. The competence of individual oocytes for maturation and fertilization were assessed after IVM and ICSI with donated sperm samples.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, isolated follicles from both groups survived up to 6 weeks with increasing diameters over the duration (P < 0.05), reaching terminal diameters of almost 1 mm with confirmed steroidogenesis and expression of oocyte marker (DDX4), and producing morphologically normal MII oocytes. When compared with the control group, the NT4 group had a similar initial follicular diameter (206 ± 61.3 vs 184 ± 93.4 μm) but exhibited a significant increase in follicular diameter from the ninth day of culture onwards (P < 0.05). From Week 3, estradiol and progesterone production were significantly increased in the NT4 group, while no significant difference was observed in AMH production between groups. The proportion of 'fast-growth' follicles in the NT4 group was significantly higher than that in the control group (13/23 vs 6/24, P < 0.05). An increased efficiency of MII oocyte maturation per live follicle in the NT4 group was also observed (control group vs NT4 group, 4/24 vs 10/23, P < 0.05). It is noteworthy that an MII oocyte obtained from the control group exhibited abnormal fertilization after ICSI. In contrast, an MII oocyte acquired from the NT4 group progressed to the blastocyst stage and showed potential for transfer.

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

The cohort examined in this study was all patients diagnosed with beta-thalassemia major. Whether this culture system is effective for patients with other diseases remains unknown. Since the chosen dose of NT4 was established based on dose finding in mice, the optimal dose for use in a human IVG system needs further confirmation. The oocytes and embryos procured from this study have not been quantified for ploidy status or epigenetic signatures.

WIDER IMPLICATIONS OF THE FINDINGS

Fresh medulla tissue obtained during tissue preparation for OTC may serve as a precious source of fertilizable oocytes for female fertility preservation, even for pre-pubertal girls, without the threat of tumour reintroduction. After further characterization and optimization of the system, this culture system holds the potential to provide a powerful future research tool, for the comprehensive exploration of human follicular development mechanisms and for conducting reproductive toxicity evaluations.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the National Key R&D Program of China (grant number 2022YFC2703000) and National Natural Science Foundation of China (grant numbers 82271651 and 81871214). The medium used in human follicle in vitro culture in this study has been applied for a national invention patent in China (No. 202211330660.7). The inventors of the patent, in order, are: Y.G., C.F., and X.L.

Current Position of Oncofertility in Adolescent Female Cancer Patients: A Comparative Review on Society Guidelines

Fertility preservation (FP) in pediatric and adolescent oncology patients presents a complex interplay between cancer treatment imperatives and reproductive aspirations, demanding a multi-disciplinary approach. Essential guidelines emphasize the importance of early referrals to FP specialists, ensuring timely counseling on oocyte and ovarian tissue cryopreservation options. Proper patient selection and risk assessment, considering intrinsic and extrinsic factors, is crucial for judicious resource utilization and optimal outcomes. Gonadotoxic effects of cancer treatments pose significant threats to reproductive capabilities. Oocyte cryopreservation (OC) is preferred in post-pubertal adolescents without partners. Cultural and religious concerns, especially regarding hymenal integrity, influence FP decisions, necessitating culturally sensitive consent processes. Ovarian tissue cryopreservation (OTC) offers an alternative for those unfit for OC. Despite its experimental label in some societies, emerging data support the efficacy of OTC, with ovarian tissue transplantation (OTT) showing promise in restoring ovarian function. However, the reintroduction of potentially malignant cells during transplantation remains a concern. Overall, while FP offers hope for future parenthood, the intricacies of decision-making and the potential medical, ethical, and cultural challenges underscore the importance of a personalized, multi-disciplinary approach. In this review, guidelines from various societies have been comprehensively reviewed and analyzed to provide insight into the clinical practice of oncofertility.

Preservation of fertility in female and male prepubertal patients diagnosed with cancer

Over the past two decades, the importance of fertility preservation has grown not only in the realm of medical and clinical patient care, but also in the field of basic and applied research in human reproduction. With advancements in cancer treatments resulting in higher rates of patient survival, it is crucial to consider the quality of life post-cure. Therefore, fertility preservation must be taken into account prior to antitumor treatments, as it can significantly impact a patient's future fertility. For postpubertal patients, gamete cryopreservation is the most commonly employed preservation strategy. However, for prepubertal patients, the situation is more intricate. Presently, ovarian tissue cryopreservation is the standard practice for prepubertal girls, but further scientific evidence is required in several aspects. Testicular tissue cryopreservation, on the other hand, is still experimental for prepubertal boys. The primary aim of this review is to address the strategies available for possible fertility preservation in prepubertal girls and boys, such as ovarian cryopreservation/transplantation, in vitro follicle culture and meiotic maturation, artificial ovary, transplantation of cryopreserved spermatogonia, and cryopreservation/grafting of immature testicular tissue and testicular organoids.

Thiol-yne click crosslink hyaluronic acid/chitosan hydrogel for three-dimensional in vitro follicle development

There is a great deal of potential for in vitro follicle growth to provide an alternative approach to fertility preservation. This strategy reduces the possibility of cancer cells re-exposure after transplantation, and it does not require hormone stimulation. Adopting a three-dimensional (3D) culture method helps preserve the architecture of the follicle and promotes the maturity of oocytes. In order to maintain follicle morphology, enhance the quality of mature oocytes, and facilitate meiotic spindle assembly, the current work aimed to develop the 3D in vitro preantral mouse follicle culture method. Thiolated chitosan-co-thiolated hyaluronic (CSHS) hydrogel was designed to evaluate the effects of biomaterials on ovarian follicle development. Isolated follicles from mouse ovaries were randomly divided into alginate (Alg) as a 3D control, thiolated hyaluronic acid (HASH), and CSHS groups. Single follicle was encapsulated in each hydrogel, and performed for 10 days and subsequently ovulated to retrieve mature oocytes on day 11. CSHS hydrogel promoted follicle survival and oocyte viability with maintained spherical morphology of follicle. Matured oocytes with normal appearance of meiotic spindle and chromosome alignment were higher in the CSHS group compared with those in the Alg and HASH groups. Furthermore, CSHS increased expression level of folliculogenesis genes (TGFβ-1, GDF-9) and endocrine-related genes (LHCGR, and FSHR). With various experimental setups and clinical applications, this platform could be applied as an alternative method to in vitro follicle culture with different experimental designs and clinical applications in the long-term period.

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.

Reference standards for follicular density in ovarian cortex from birth to sexual maturity

RESEARCH QUESTION

Are age-normalized reference values for human ovarian cortical follicular density adequate for tissue quality control in fertility preservation?

DESIGN

Published quantitative data on the number of follicles in samples without known ovarian pathology were converted into cortical densities to create reference values. Next, a sample cohort of 126 girls (age 1-24 years, mean ± SD 11 ± 6) with cancer, severe haematological disease or Turner syndrome were used to calculate Z-scores for cortical follicular density based on the reference values.

RESULTS

No difference was observed between Z-scores in samples from untreated patients (0.3 ± 3.5, n = 30) and patients treated with (0.5 ± 2.9, n = 48) and without (0.1 ± 1.3, n = 6) alkylating chemotherapy. Z-scores were not correlated with increasing cumulative exposure to cytostatics. Nevertheless, Z-scores in young treated patients (0-2 years -2.1 ± 3.1, n = 10, P = 0.04) were significantly lower than Z-scores in older treated patients (11-19 years, 2 ± 1.9, n = 15). Samples from patients with Turner syndrome differed significantly from samples from untreated patients (-5.2 ± 5.1, n = 24, P = 0.003), and a Z-score of -1.7 was identified as a cut-off showing good diagnostic value for identification of patients with Turner syndrome with reduced ovarian reserve. When this cut-off was applied to other patients, analysis showed that those with indications for reduced ovarian reserve (n = 15) were significantly younger (5.9 ± 4.2 versus 10.7 ± 5.9 years, P = 0.004) and, when untreated, more often had non-malignant haematologic diseases compared with those with normal ovarian reserve (n = 24, 100% versus 19%, P = 0.009).

CONCLUSION

Z-scores allow the estimation of genetic- and treatment-related effects on follicular density in cortical tissue from young patients stored for fertility preservation. Understanding the quality of cryopreserved tissue facilitates its use during patient counselling. More research is needed regarding the cytostatic effects found in this study.

Making a good egg: human oocyte health, aging, and in vitro development

Mammalian eggs (oocytes) are formed during fetal life and establish associations with somatic cells to form primordial follicles that create a store of germ cells (the primordial pool). The size of this pool is influenced by key events during the formation of germ cells and by factors that influence the subsequent activation of follicle growth. These regulatory pathways must ensure that the reserve of oocytes within primordial follicles in humans lasts for up to 50 years, yet only approximately 0.1% will ever be ovulated with the rest undergoing degeneration. This review outlines the mechanisms and regulatory pathways that govern the processes of oocyte and follicle formation and later growth, within the ovarian stroma, through to ovulation with particular reference to human oocytes/follicles. In addition, the effects of aging on female reproductive capacity through changes in oocyte number and quality are emphasized, with both the cellular mechanisms and clinical implications discussed. Finally, the details of current developments in culture systems that support all stages of follicle growth to generate mature oocytes in vitro and emerging prospects for making new oocytes from stem cells are outlined.

Beyond apoptosis: evidence of other regulated cell death pathways in the ovary throughout development and life

BACKGROUND

Regulated cell death is a fundamental component of numerous physiological processes; spanning from organogenesis in utero, to normal cell turnover during adulthood, as well as the elimination of infected or damaged cells throughout life. Quality control through regulation of cell death pathways is particularly important in the germline, which is responsible for the generation of offspring. Women are born with their entire supply of germ cells, housed in functional units known as follicles. Follicles contain an oocyte, as well as specialized somatic granulosa cells essential for oocyte survival. Follicle loss-via regulated cell death-occurs throughout follicle development and life, and can be accelerated following exposure to various environmental and lifestyle factors. It is thought that the elimination of damaged follicles is necessary to ensure that only the best quality oocytes are available for reproduction.

OBJECTIVE AND RATIONALE

Understanding the precise factors involved in triggering and executing follicle death is crucial to uncovering how follicle endowment is initially determined, as well as how follicle number is maintained throughout puberty, reproductive life, and ovarian ageing in women. Apoptosis is established as essential for ovarian homeostasis at all stages of development and life. However, involvement of other cell death pathways in the ovary is less established. This review aims to summarize the most recent literature on cell death regulators in the ovary, with a particular focus on non-apoptotic pathways and their functions throughout the discrete stages of ovarian development and reproductive life.

SEARCH METHODS

Comprehensive literature searches were carried out using PubMed and Google Scholar for human, animal, and cellular studies published until August 2022 using the following search terms: oogenesis, follicle formation, follicle atresia, oocyte loss, oocyte apoptosis, regulated cell death in the ovary, non-apoptotic cell death in the ovary, premature ovarian insufficiency, primordial follicles, oocyte quality control, granulosa cell death, autophagy in the ovary, autophagy in oocytes, necroptosis in the ovary, necroptosis in oocytes, pyroptosis in the ovary, pyroptosis in oocytes, parthanatos in the ovary, and parthanatos in oocytes.

OUTCOMES

Numerous regulated cell death pathways operate in mammalian cells, including apoptosis, autophagic cell death, necroptosis, and pyroptosis. However, our understanding of the distinct cell death mediators in each ovarian cell type and follicle class across the different stages of life remains the source of ongoing investigation. Here, we highlight recent evidence for the contribution of non-apoptotic pathways to ovarian development and function. In particular, we discuss the involvement of autophagy during follicle formation and the role of autophagic cell death, necroptosis, pyroptosis, and parthanatos during follicle atresia, particularly in response to physiological stressors (e.g. oxidative stress).

WIDER IMPLICATIONS

Improved knowledge of the roles of each regulated cell death pathway in the ovary is vital for understanding ovarian development, as well as maintenance of ovarian function throughout the lifespan. This information is pertinent not only to our understanding of endocrine health, reproductive health, and fertility in women but also to enable identification of novel fertility preservation targets.

Ovarian stimulation and oocyte cryopreservation in females and transgender males aged 18 years or less: a systematic review

Background

Fertility preservation is an important healthcare focus in the paediatric and adolescent population when gonadotoxic treatments are required. Ovarian stimulation (OS) resulting in oocyte cryopreservation is a well-established fertility preservation option in the adult population. It's utility, however, is little known in young patients. The purpose of this review was to synthesise the available literature on OS in patients ≤18 years old, to identify gaps in current research and provide suggestions for future research directions.

Methods

Using PRISMA guidelines, a systematic review of the literature was performed for all relevant full-text articles published in English in Medline, Embase, the Cochrane Library and Google Scholar databases. The search strategy used a combination of subject headings and generic terms related to the study topic and population. Two reviewers independently screened studies for eligibility, extracted data and assessed the risk of bias. Characteristics of the studies, objectives and key findings were extracted and summarised in a narrative synthesis.

Results

Database search and manual review identified 922 studies, 899 were eliminated based on defined exclusion criteria. Twenty-three studies were included and comprised 468 participants aged ≤18 years who underwent OS (median 15.2, range 7-18 years old). Only three patients were premenarchal, and four patients were on treatment to suppress puberty. Patients had OS for a broad range of indications including oncology treatment, transgender care and Turner syndrome. A total of 488 cycles of OS were completed, with all but 18 of these cycles (96.3%) successfully resulting in cryopreserved mature oocytes (median 10 oocytes, range 0-35). Fifty-three cycles (9.8%) were cancelled. Complications were rare (<1%). One pregnancy was reported from a female who had OS aged 17 years old.

Conclusion

This systematic review demonstrates that OS and oocyte cryopreservation is achievable in young females however there are only a few cases in the literature describing OS in premenarcheal children or those who have suppressed puberty. There is little proof that OS can lead to pregnancy in adolescents, and no proof that this can be achieved in premenarchal girls. Therefore it should be regarded as an innovative procedure for adolescents and experimental for premenarcheal girls.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=265705, identifier CRD42021265705.

Long-term follow-up to assess criteria for ovarian tissue cryopreservation for fertility preservation in young women and girls with cancer

STUDY QUESTION

Do the Edinburgh Selection Criteria correctly identify female cancer patients under the age of 18 who are at risk of premature ovarian insufficiency (POI) as candidates for ovarian tissue cryopreservation (OTC)?

SUMMARY ANSWER

Patient assessment using these criteria accurately identifies those at risk of POI, who can be offered OTC and future transplantation as a means of fertility preservation.

WHAT IS KNOWN ALREADY

Treatment for childhood cancer can have adverse consequences on future fertility; at the time of diagnosis, fertility risk assessment should be undertaken in order to identify patients to whom fertility preservation should be offered. The Edinburgh selection criteria, based on planned cancer treatment and patient health status, are utilized to identify those at high risk and therefore eligible for OTC. However, this procedure is not without risk and there are few data on the efficacy of the procedure in prepubertal patients. As such, long-term follow-up of reproductive outcomes is necessary, to ensure that OTC is being offered appropriately.

STUDY DESIGN, SIZE, DURATION

Cohort study encompassing all females diagnosed with cancer under the age of 18 in South East Scotland, from 1 January 1996 to 30 April 2020. Patients were followed up for reproductive outcomes to assess for diagnosis of POI.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 638 eligible patients were identified; patients under the age of 12 or deceased before the age of 12 were excluded from the study, leaving a study population of 431 patients. Electronic records were reviewed for reproductive function, assessed by current menstruation, pregnancy (in the absence of POI diagnosis), reproductive hormone measurements, pubertal progression, or diagnosis of POI. Patients on hormonal contraception (other than for treatment of POI or panhypopituitarism with no history of gonadatoxic treatment) were excluded from analysis (n = 9). Analysis on remaining 422 patients was carried out using the Kaplan-Meier methods, with POI as the defined event, and Cox proportional hazards model.

MAIN RESULTS AND THE ROLE OF CHANCE

In the study population of 431 patients, median ages at diagnosis and analysis were 9.8 and 22.2 years, respectively. Reproductive outcomes were unavailable in 142 patients; the assumption was made that these patients did not have POI, but a subanalysis excluding these patients was also performed. Of the 422 patients aged >12 at analysis and not taking hormonal contraception, OTC was offered to 37 patients and successfully performed in 25 patients. Of the 37 patients offered OTC (one at time of relapse), nine (24.3%) developed POI. Of the 386 not offered OTC, 11 (2.9%) developed POI. The probability of developing POI was significantly higher in those offered OTC (hazard ratio [HR] 8.7 [95% CI 3.6-21]; P < 0.0001), even when those patients with unknown outcomes were excluded from the analysis (HR 8.1 [95% CI 3.4-20]; P < 0.001). All patients offered OTC who developed POI did so after treatment for primary disease; in those not offered OTC, five patients (45.5%) developed POI after treatment for disease relapse.

LIMITATIONS, REASONS FOR CAUTION

A significant number of patients had unknown reproductive outcomes; many of these patients were engaged in ongoing follow-up but did not have documented reproductive assessment. This may have introduced bias to the analysis and highlights the need for reproductive follow-up as part of routine cancer aftercare. In addition, the relatively young age of the patient population and short duration of follow-up in some cases demonstrates the need for ongoing follow-up of this cohort.

WIDER IMPLICATIONS OF THE FINDINGS

The prevalence of POI after childhood cancer is low, but the Edinburgh selection criteria remain a robust tool for selecting those at high risk at the time of diagnosis, to offer OTC appropriately. However, disease relapse necessitating more intensive treatments remains a challenge. This study additionally highlights the importance of routine assessment and documentation of reproductive status in haematology/oncology follow-up.

STUDY FUNDING/COMPETING INTEREST(S)

K.D. is supported by a CRUK grant (C157/A25193). This work was undertaken in part in the MRC Centre for Reproductive Health, (supported by MRC grant MR/N022556/1). R.A.A. has received consulting fees from Ferring and Roche Diagnostics; payment from Merck and IBSA for educational events; and laboratory materials from Roche Diagnostics. The other authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

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.

The metallic compound promotes primordial follicle activation and ameliorates fertility deficits in aged mice

Background: Aged women and premature ovarian insufficiency (POI) patients have residual dormant primordial follicles that are hard to be activated through a physiological process. However, there are no effective and safe drugs to help them. Methods: We used the in vitro culture model of newborn mouse ovaries to identify the drugs that promote primordial follicle activation and study its mechanisms. It was verified by in vivo injection model of newborn mice and in vitro culture model of human ovarian tissue. In addition, we used the aged mice as a low infertility model to verify the effects of primordial follicle activation, and fertility by drugs. Results: Eleven metallic compounds activated mouse primordial follicles, and the five most effective compounds were selected for further study. Thapsigargin (TG), CrCl3, MnCl2, FeCl3 and ZnSO4 increased the levels of the glycolysis-related proteins (glucose transporter type 4, GLUT4; hexokinase 1, HK1; pyruvate kinase M2, PKM2; phosphofructokinase, liver type, PFKL), phosphorylated mammalian target of rapamycin (p-mTOR) in cultured mouse ovaries. The compound-promoted p-mTOR levels could be completely blocked by 2-DG (the inhibitor of glycolysis). The compounds also increased the levels of phosphorylated protein kinase B (p-Akt). TG-, CrCl3- and FeCl3-promoted p-Akt levels, but not MnCl2- and ZnSO4- promoted p-Akt levels, could be completely blocked by ISCK03 (the inhibitor of proto-oncogenic receptor tyrosine kinase, KIT). The injection of newborn mice with the compounds also activated primordial follicles and increased the levels of the glycolysis-related proteins, p-mTOR, and p-Akt. The oral administration of the compounds in adolescent and aged mice promoted primordial follicle activation, and had no obvious side effect. Importantly, ZnSO4 also increased ovulated oocytes, oocyte quality and offspring in aged mice. Furthermore, the compounds promoted human primordial follicle activation and increased the levels of the glycolysis-related proteins, p-mTOR, and p-Akt. Conclusion: The metallic compounds activate primordial follicles through the glycolysis-dependent mTOR pathway and/or the PI3K/Akt pathway, and the oral administration of ZnSO4 enhances fertility in aged mice. We suggest that these metallic compounds may be oral drugs to ameliorate fertility deficits in aged women and POI patients.

Prospects for fertility preservation: the ovarian organ function reconstruction techniques for oogenesis, growth and maturation in vitro

Today, fertility preservation is receiving more attention than ever. Cryopreservation, which preserves ovarian tissue to preserve fertility in young women and reduce the risk of infertility, is currently the most widely practiced. Transplantation, however, is less feasible for women with blood-borne leukemia or cancers with a high risk of ovarian metastasis because of the risk of cancer recurrence. In addition to cryopreservation and re-implantation of embryos, in vitro ovarian organ reconstruction techniques have been considered as an alternative strategy for fertility preservation. In vitro culture of oocytes in vitro Culture, female germ cells induction from pluripotent stem cells (PSC) in vitro, artificial ovary construction, and ovaria-related organoids construction have provided new solutions for fertility preservation, which will therefore maximize the potential for all patients undergoing fertility preservation. In this review, we discussed and thought about the latest ovarian organ function reconstruction techniques in vitro to provide new ideas for future ovarian disease research and fertility preservation of patients with cancer and premature ovarian failure.

Spatio-temporal remodelling of the composition and architecture of the human ovarian cortical extracellular matrix during in vitro culture

STUDY QUESTION

How does in vitro culture alter the human ovarian cortical extracellular matrix (ECM) network structure?

SUMMARY ANSWER

The ECM composition and architecture vary in the different layers of the ovarian cortex and are remodelled during in vitro culture.

WHAT IS KNOWN ALREADY

The ovarian ECM is the scaffold within which follicles and stromal cells are organized. Its composition and structural properties constantly evolve to accommodate follicle development and expansion. Tissue preparation for culture of primordial follicles within the native ECM involves mechanical loosening; this induces undefined modifications in the ECM network and alters cell-cell contact, leading to spontaneous follicle activation.

STUDY DESIGN, SIZE, DURATION

Fresh ovarian cortical biopsies were obtained from six women aged 28-38 years (mean ± SD: 32.7 ± 4.1 years) at elective caesarean section. Biopsies were cut into fragments of ∼4 × 1 × 1 mm and cultured for 0, 2, 4, or 6 days (D).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Primordial follicle activation, stromal cell density, and ECM-related protein (collagen, elastin, fibronectin, laminin) positive area in the entire cortex were quantified at each time point using histological and immunohistological analysis. Collagen and elastin content, collagen fibre characteristics, and follicle distribution within the tissue were further quantified within each layer of the human ovarian cortex, namely the outer cortex, the mid-cortex, and the cortex-medulla junction regions.

MAIN RESULTS AND THE ROLE OF CHANCE

Primordial follicle activation occurred concomitantly with a loosening of the ovarian cortex during culture, characterized by an early decrease in stromal cell density from 3.6 ± 0.2 × 106 at day 0 (D0) to 2.8 ± 0.1 × 106 cells/mm3 at D2 (P = 0.033) and a dynamic remodelling of the ECM. Notably, collagen content gradually fell from 55.5 ± 1.7% positive area at D0 to 42.3 ± 1.1% at D6 (P = 0.001), while elastin increased from 1.1 ± 0.2% at D0 to 1.9 ± 0.1% at D6 (P = 0.001). Fibronectin and laminin content remained stable. Moreover, collagen and elastin distribution were uneven throughout the cortex and during culture. Analysis at the sub-region level showed that collagen deposition was maximal in the outer cortex and the lowest in the mid-cortex (69.4 ± 1.2% versus 53.8 ± 0.8% positive area, respectively, P < 0.0001), and cortical collagen staining overall decreased from D0 to D2 (65.2 ± 2.4% versus 60.6 ± 1.8%, P = 0.033) then stabilized. Elastin showed the converse distribution, being most concentrated at the cortex-medulla junction (3.7 ± 0.6% versus 0.9 ± 0.2% in the outer cortex, P < 0.0001), and cortical elastin peaked at D6 compared to D0 (3.1 ± 0.5% versus 1.3 ± 0.2%, P < 0.0001). This was corroborated by a specific signature of the collagen fibre type across the cortex, indicating a distinct phenotype of the ovarian cortical ECM depending on region and culture period that might be responsible for the spatio-temporal and developmental pattern of follicular distribution observed within the cortex.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Ovarian cortical biopsies were obtained from women undergoing caesarean sections. As such, the data obtained may not accurately reflect the ECM distribution and structure of non-pregnant women.

WIDER IMPLICATIONS OF THE FINDINGS

Clarifying the composition and architecture signature of the human ovarian cortical ECM provides a foundation for further exploration of ovarian microenvironments. It is also critical for understanding the ECM-follicle interactions regulating follicle quiescence and awakening, leading to improvements in both in vitro activation and in vitro growth techniques.

STUDY FUNDING/COMPETING INTEREST(S)

Medical Research Council grant MR/R003246/1 and Wellcome Trust Collaborative Award in Science: 215625/Z/19/Z. The authors have no conflicts to declare.

TRIAL REGISTRATION NUMBER

N/A.

Role of apoptosis and autophagy in ovarian follicle pool decline in children and women diagnosed with benign or malignant extra-ovarian conditions

STUDY QUESTION

Which biological mechanisms are responsible for physiological ovarian reserve decline owing to aging, or pathological follicle depletion triggered by inflammation or a pro-oxidant environment throughout a woman's lifetime?

SUMMARY ANSWER

Ovarian follicle pool size is modulated by both apoptosis and autophagy, the first responsible for its physiological decline over time and increasing in the event of prior chemotherapy in children, and the latter playing a major role in physiological ovarian follicle pool diminution before puberty.

WHAT IS KNOWN ALREADY

Among the different pathways of controlled cell death, apoptosis and autophagy are implicated in follicle loss. Apoptosis participates in eliminating damaged follicles, such as those impaired by chemotherapy (CHT), but its involvement in physiological age-related follicle decline is less well understood. Autophagy has proved crucial in follicle quiescence maintenance in murine models, but its contribution to human follicle pool modulation is still unclear.

STUDY DESIGN, SIZE, DURATION

This retrospective study included 84 patients with benign or malignant extra-ovarian conditions aged between 1 and 35 years, with ovarian tissue stored for histological analyses at the time of cryopreservation (between 2012 and 2021) at a tertiary care center.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ovarian fragments were used for the following analyses: hematoxylin and eosin staining for follicle count and classification; cleaved caspase-3 immunostaining to identify follicle apoptosis; and microtubule-associated proteins 1A/1B light chain 3B immunolabeling to detect follicle autophagy. Transmission electron microscopy was also carried out to investigate ultrastructural features of oocytes and granulosa cells. All analyses stratified patients by age, menarchal status (premenarchal = 32; postmenarchal = 52), potentially gonadotoxic CHT before cryopreservation (n = 14), presence of endometriosis and use of hormonal treatment.

MAIN RESULTS AND THE ROLE OF CHANCE

Premenarchal patients had a larger follicle pool in terms of total follicle density [mean, range 4979.98 (342.2-21789) versus 918.8 (26.18-3983), P < 0.001], but higher rates of morphologically abnormal [8.52 (0-25.37)% versus 3.54 (0-17.5)%, P < 0.001] and atretic [15.8 (0‒31.85)% versus 10.6 (0-33.33)%, P < 0.01] follicles than postmenarchal subjects. Apoptosis rates did not change with increasing age [27.94 (0-93.2)% in prepubertal subjects and 29.5 (0-100)% in postpubertal subjects], but autophagic follicles were around 10 times more common in premenarchal than postmenarchal subjects [10.21 (0-62.3)% versus 1.34 (0-25)%, P < 0.001], playing a crucial role in age-related follicle decline and elimination of 'abnormal' follicles, that are rarely seen after menarche. The impact of diagnosis and previous CHT varied according to age. In premenarchal patients with previous CHT, significantly more apoptotic [40.22 (0-100)% versus 26.79 (0-87)%, P < 0.05] and fewer abnormal [3.84 (0-10-76)% versus 9.83 (0-25.37)%, P < 0.01] follicles were detected than in subjects with no CHT prior to ovarian tissue cryopreservation, suggesting a direct effect on follicle elimination, especially of those with abnormalities. In postmenarchal subjects with previous CHT, quiescent follicle rates were lower than in patients with no CHT before tissue freezing [71.57 (0-100)% versus 85.89 (50-100)%, P < 0.05], suggesting accelerated follicle activation and growth. Moreover, increased autophagic activity was observed in the event of a cancer diagnosis compared to benign conditions after puberty [26.27 (0-100)% versus 9.48 (0-29.41)%, respectively, P < 0.05].

LIMITATIONS, REASONS FOR CAUTION

The impact of specific CHT protocols could not be investigated since the group of patients with previous CHT was highly heterogeneous.

WIDER IMPLICATIONS OF THE FINDINGS

This study yields a deeper understanding of regulation of the follicle pool decline, showing for the first time that both apoptosis and autophagy pathways are involved in physiological follicle depletion, the latter being crucial before puberty. Moreover, our data showed a different response to non-physiological damage according to age, with higher apoptosis rates only in premenarchal subjects with previous CHT, confirming that this pathway is activated by drugs known to induce DNA damage in oocytes, such as alkylating agents, but not by cancer itself.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (F.R.S.-FNRS/FRIA FC29657 awarded to L.C., CDR J.0063.20 and grant 5/4/150/5 awarded to M.M.D.), grants from the Fondation contre le Cancer (grant 2018-042 awarded to A.Ca.), the Fondazione Comunitaria del Varesotto and Provincia di Varese ('Amalia Griffini' Fellowship in Gynecology and Obstetrics awarded to A.Ce.), Fonds Spéciaux de Recherche, Fondation St Luc and donations from the Ferrero family. The authors have no competing interests to declare.

TRIAL REGISTRAION NUMBER

N/A.

Proteolytic activation of anti-Müllerian hormone is suppressed in adolescent girls

PURPOSE

The ratio of the anti-Müllerian hormone (AMH) precursor (proAMH) to active AMH (AMH_N,C) is higher in childhood than in adulthood but has never been quantified during adolescence. The ratio of proAMH to total AMH (AMH prohormone index, API) was examined during the puberty in healthy girls. The API was also compared between girls with and without polycystic ovary syndrome (PCOS) to determine if there were differences that could assist in PCOS diagnosis during adolescence.

METHODS

Total AMH and proAMH were measured by immunoassay in a single-centre, cross-sectional observational study; 61 controls and 29 girls with PCOS were included in the study (age range 8-21 years). The API was calculated as proAMH as a percentage of total AMH. Differences in API between control and PCOS subjects and across age-groups were examined by Welch's ANOVA. The relationship between API and a range of metabolic parameters was examined by Pearson correlation.

RESULTS

The API in healthy females increased between the ages of 10~15 years and declined from 15~20 years (p < 0.001). The API was negatively correlated with body mass index in the control (p = 0.04) and PCOS groups (p = 0.007). The API was associated with factors related to adiposity and lipid metabolism. The API was not significantly different in control girls and girls with PCOS.

CONCLUSIONS

Higher API during adolescence suggests that proteolytic activation of proAMH is suppressed during this life stage. API was not different between control girls and girls with PCOS indicating that it is not useful in diagnosis of PCOS during adolescence.

Proteome-wide and matrisome-specific atlas of the human ovary computes fertility biomarker candidates and open the way for precision oncofertility

Our modern era is witnessing an increasing infertility rate worldwide. Although some of the causes can be attributed to our modern lifestyle (e.g., persistent organic pollutants, late pregnancy), our knowledge of the human ovarian tissue has remained limited and insufficient to reverse the infertility statistics. Indeed, all efforts have been focused on the endocrine and cellular function in support of the cell theory that dates back to the 18th century, while the human ovarian matrisome is still under-described. Hereby, we unveil the extracellular side of the story during different periods of the ovary life, demonstrating that follicle survival and development, and ultimately fertility, would not be possible without its involvement. We examined the human ovarian matrisome and described its remodeling from prepuberty until menopause, creating the first ovarian proteomic codex. Here, we confidently identified and quantified 98 matrisome proteins present in the three ovary groups. Among them, 26 were expressed differently among age groups, delineating a peculiar matrisomal fingerprint at each stage. Such proteins could be potential biomarkers phenotyping ovarian ECM at each age phase of female reproductive life. Beyond proteomics, our study presents a unique approach to understanding the data and depicting the spatiotemporal ECM-intracellular signaling networks and remodeling with age through imaging, advanced text-mining based on natural language processing technology, machine learning, and data sonification. Our findings provide essential context for healthy ovarian physiology, identifying and characterizing disease states, and recapitulating physiological tissues or development in vitro. This comprehensive proteomics analysis represents the ovarian proteomic codex and contributes to an improved understanding of the critical roles that ECM plays throughout the ovarian life span.

Therapeutic Potential of In Vitro-Derived Oocytes for the Restoration and Treatment of Female Fertility

Considerable progress has been made with the development of culture systems for the in vitro growth and maturation (IVGM) of oocytes from the earliest-staged primordial follicles and from the more advanced secondary follicles in rodents, ruminants, nonhuman primates, and humans. Successful oocyte production in vitro depends on the development of a dynamic culture strategy that replicates the follicular microenvironment required for oocyte activation and to support oocyte growth and maturation in vivo while enabling the coordinated and timely acquisition of oocyte developmental competence. Significant heterogeneity exists between the culture protocols used for different stages of follicle development and for different species. To date, the fertile potential of IVGM oocytes derived from primordial follicles has been realized only in mice. Although many technical challenges remain, significant advances have been made, and there is an increasing consensus that complete IVGM will require a dynamic, multiphase culture approach. The production of healthy offspring from in vitro-produced oocytes in a secondary large animal species is a vital next step before IVGM can be tested for therapeutic use in humans.

Enhanced glycolysis in granulosa cells promotes the activation of primordial follicles through mTOR signaling

In mammals, nonrenewable primordial follicles are activated in an orderly manner to maintain the longevity of reproductive life. Mammalian target of rapamycin (mTOR)-KIT ligand (KITL) signaling in pre-granulosa cells and phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt)-forkhead Box O3a (FOXO3a) signaling in oocytes are important for primordial follicle activation. The activation process is accompanied by the enhancement of energy metabolism, but the causal relationship is unclear. In the present study, the levels of glycolysis-related proteins GLUT4, HK1, PFKL, and PKM2 were significantly increased in granulosa cells but were decreased in oocytes during the mouse primordial-to-primary follicle transition. Both short-term pyruvate deprivation in vitro and acute fasting in vivo increased the glycolysis-related gene and protein levels, decreased AMPK activity, and increased mTOR activity in mouse ovaries. The downstream pathways Akt and FOXO3a were phosphorylated, resulting in mouse primordial follicle activation. The blockade of glycolysis by 2-deoxyglucose (2-DG), but not the blockade of the communication network between pre-granulosa cells and oocyte by KIT inhibitor ISCK03, decreased short-term pyruvate deprivation-promoted mTOR activity. Glycolysis was also increased in human granulosa cells during the primordial-to-primary follicle transition, and short-term pyruvate deprivation promoted the activation of human primordial follicles by increasing the glycolysis-related protein levels and mTOR activity in ovarian tissues. Taken together, the enhanced glycolysis in granulosa cells promotes the activation of primordial follicles through mTOR signaling. These findings provide new insight into the relationship between glycolytic disorders and POI/PCOS.

Effect of Previous Alkylating Agent Exposure on Follicle Numbers in Cryopreserved Prepubertal and Young Adult Ovarian Tissue after Long-Term Xenografting

Simple Summary

Cryopreservation of ovarian tissue is a promising technique for fertility preservation in cancer patients at increased risk for subfertility. The International Guideline Harmonization Group recommends ovarian tissue cryopreservation for children and young adults before therapy with cumulative doses of alkylating agent at or above 6000–8000 mg/m². A therapy that poses a high risk of subfertility is rarely the first-line therapy and many of the patients have already undergone several regimens of chemotherapy. The aim of our study was to assess the effects of chemotherapy exposures on the quality of cryopreserved ovarian tissue. We confirmed the harmful effects of alkylating agents on xenografted ovarian tissue and suggest that cumulative doses which are not regarded as an indication for fertility preservation in children and young adult may decrease the quality of cryopreserved follicles.

Abstract

Purpose and methods: To elucidate whether previous cancer treatment affects graft recovery and follicle numbers, morphology, and development in grafts, cryopreserved ovarian biopsies obtained from 18 cancer patients aged 1–24 years with and without exposure to chemotherapy were xenografted as 1 mm³ fragments to immunodeficient mice for 22 weeks with exogenous stimulation. Results: Graft recovery showed no association with chemotherapy exposure, pubertal stage, or leukemia contamination. Total follicle number per recovered graft varied between 0 and 1031 in the chemotherapy-exposed and between 0 and 502 in the non-chemotherapy-exposed group. Atretic follicles formed the largest proportion of the follicle pool in chemotherapy-exposed grafts. Increased atresia correlated with exposure to alkylating agents (mean ± SD 8866.2 ± 9316.3 mg/m²) but not with anthracyclines, pubertal stage, or leukemia contamination. Conclusion: The observation confirms the harmful effects of alkylating agents on ovarian tissue. Therapy at the median cumulative dose of 8866 mg/m² leads to the decreased quality of cryopreserved ovarian follicles in children and young adults.

Fertility Preservation for Prepubertal Patients at Risk of Infertility: Present Status and Future Perspectives

The increasing cure rate of cancer has led to a vast population of survivors having to face the late adverse effects of oncological treatments, with fertility impairment being one of the most sensitive issues for patients. Different options to preserve the fertility of adult patients are routinely used in clinical practice. However, fertility preservation strategies for prepubertal patients at risk of infertility are limited to the cryopreservation of immature gonadal tissue. In recent decades, many research efforts have been focused on the future use of cryopreserved gonadal tissue. This review discusses the common status of fertility preservation measures for pediatric patients undergoing gonadotoxic treatment, focusing especially on the challenges that remain to be solved in order to implement this fundamental service.

Factors Influencing the In Vitro Maturation (IVM) of Human Oocyte

In vitro maturation (IVM) of oocytes is a promising assisted reproductive technology (ART) deemed as a simple and safe procedure. It is mainly used in patients with impaired oocyte maturation and in fertility preservation for women facing the risk of losing fertility. However, to date, it is still not widely used in clinical practice because of its underperformance. The influencing factors, such as biphasic IVM system, culture medium, and the supplementation, have a marked effect on the outcomes of oocyte IVM. However, the role of different culture media, supplements, and follicular priming regimens in oocyte IVM have yet to be fully clarified and deserve further investigation.

In vitro production of viable eggs from isolated mouse primary follicles by successive culture

To produce viable eggs from single primary follicles in vitro, primary follicles containing oocytes (average 39.0 ± 0.2 µm in diameter) were isolated from the ovaries of 1-week-old mice, and cultured in combination with culture membranes for the first 8 days up to the secondary follicle stage, followed by the next 12 days to the later stages. After culture with a combination of first and second culture membranes using high and low adhesion characteristics, the average oocyte diameters of the surviving follicles increased by almost two-fold in all four groups. Further, the oocyte maturation rate was the highest (74.1%) in the culture group with low adhesion with collagenase and high adhesion. In this culture group, when the O₂ concentration was changed from 20% in the first culture to 5% in the second culture, the cleavage rate increased to 47.5%, which was comparable to the level of the in vivo control (34.6%). Finally, 39 embryos at the 2- to 8-cell stages were transferred into the oviducts of three pseudopregnant females, and eight live pups (20.5%) were obtained. Of the eight pups, six survived for at least six months and were fertile. The present study shows successive in vitro cultures of single isolated primary follicles for the production of viable eggs. We believe that this culture system, with a combination of culture membranes under controlled O₂ conditions, is applicable to other mammalian species, including humans.

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.

Hormonal response in patients transplanted with cryopreserved ovarian tissue is independent of whether freezing was performed in childhood or adulthood

PURPOSE

This study evaluated the concentrations of hormones resulting from the transplantation of ovarian tissue (OTT) in relation to whether the tissue was frozen at a time close to puberty or above the age of 19 years.

METHODS

Six girls and adolescents (aged 9-14 years) who underwent ovarian tissue cryopreservation (OTC) were followed after transplantation in adulthood. After OTT, the women were followed via regular blood samples to evaluate the concentrations of FSH, LH, oestradiol and AMH. Twenty-three women undergoing OTT (aged 19-36 years at the time of OTC) were included as a reference group. All of the women had postmenopausal levels of gonadotropins at the time of transplantation.

RESULTS

The return of FSH and LH to normal premenopausal concentrations in adult women transplanted with ovarian tissue that was frozen at a time close to puberty was similar to the profiles in women from the reference group. Serum AMH levels were below the detection limit (via the Roche Elecsys assay) in many samples, but four out of six young girls showed measurable concentrations. Oestradiol similarly increased in the first 12 weeks following transplantation, after which it tended to be higher in women having frozen tissue in adulthood.

CONCLUSIONS

Ovarian tissue that was excised from girls at a time close to puberty, after which it was frozen and transplanted in adulthood, interacts with pituitary tissue in a similar manner to ovarian tissue that is frozen from adult women. Follicles located in the ovarian tissue from young girls are equally sensitive to gonadotropin stimulation as follicles from adult women when exposed to postmenopausal levels of gonadotropins. This result indicates that it is not the ovaries that require maturation to sustain full reproductive potential but rather proper FSH and LH stimulation. Moreover, these results support the continued use of OTC in young women.

Mitochondrial content, activity, and morphology in prepubertal and adult human ovaries

PURPOSE

To investigate whether mitochondrial content, activity, and morphology differ in prepubertal versus adult ovarian follicles.

METHODS

Ovarian tissue was collected from 7 prepubertal girls (age 1-10 years) and 6 adult women (age 20-35 years). Primordial and primary follicles were isolated from frozen-thawed prepubertal and adult ovarian tissue and their viability was assessed. Mitochondrial content was investigated by TOMM20 immunostaining of prepubertal and adult ovarian tissue, while mitochondrial activity in isolated follicles was analyzed by MitoTracker CM-H2XRos and JC-1. Frozen-thawed ovarian tissue from the same patients was also evaluated by transmission electron microscopy to examine mitochondrial morphology.

RESULTS

Higher TOMM20 staining was detected in prepubertal follicles compared to their adult counterparts, indicating the presence of more mitochondria in prepubertal follicles. Analysis of mitochondrial activity by MitoTracker showed higher fluorescence intensity in prepubertal follicles, suggesting that follicles in this group are more active than adult follicles. JC-1 analysis did not reveal any statistically significant difference in the inactive/active ratio between the two groups. Moreover, ultrastructural analysis by TEM detected morphological differences in the shape and cristae of prepubertal mitochondria, probably suggesting a mechanism of response to autophagy.

CONCLUSION

Differences in the number, activity, and morphology of mitochondria were reported, suggesting that consequential modifications might occur during puberty, which could be the window of opportunity required by mitochondria to undergo changes needed to reach maturity, and hence the capacity for ovulation and fertilization.

Effects of low-dose X-ray medical diagnostics on female gonads: Insights from large animal oocytes and human ovaries as complementary models

Diagnostic imaging has significantly grown over the last thirty years as indispensable support for diagnostic, prognostic, therapeutic and monitoring procedures of human diseases. This study explored the effects of low-dose X-ray medical diagnostics exposure on female fertility. To aim this, cumulus-oocyte complexes (COCs) recovered from the ovaries of juvenile sheep and human ovaries were used as complementary models for in vitro studies. In the sheep model, the effects of low-dose X-rays on oocyte viability and developmental competence were evaluated. In human ovaries originated from two age group (21–25 and 33–36 years old) subjects with gender dysphoria, X-rays effects on tissue morphology, follicular density and expression of apoptosis-related (NOXA, PUMA, Bcl2, Bak, γH2AX) and cell cycle-related genes (p21 and ki67) were investigated. It was noted that in sheep, the minimum dose of 10 mGy did not influence most of examined parameters at oocyte and embryo levels, whereas 50 and 100 mGy X-ray exposure reduced oocyte bioenergetic/oxidative activity but without any visible effects on oocyte and embryo development. In addition, blastocyst bioenergetic/oxidative status was reduced with all used doses. Overall data on human ovaries showed that low-dose X-rays, similarly as in sheep, did not alter any of examined parameters. However, in women belonging to the 33–36 year group, significantly reduced follicular density was observed after exposure to 50 and 100 mGy, and increased NOXA and Bax expression after exposure at 50 mGy. In conclusion, used low-doses of X-ray exposure, which resemble doses used in medical diagnostics, produce weak damaging effects on female fertility with increased susceptibility in advanced age.

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.

Figla promotes secondary follicle growth in mature mice

The in vitro growth (IVG) of human follicles is a potential fertility option for women for whom cryopreserved ovarian tissues cannot be transplanted due to the risk of cancer cell reintroduction; however, there is currently no established method. Furthermore, optimal IVG conditions may differ between the follicles of adult and pre-pubertal females due to molecular differences suggested by basic research. To systematically identify differences between the secondary follicles of adult and pre-pubertal females, a comparative transcriptomic study using mice was conducted herein. Among differentially expressed genes (DEGs), Figla was up-regulated in mature mice. We successfully down-regulated Figla expression in secondary follicle oocytes by a Figla siRNA microinjection, and the subsequent IVG of follicles showed that the diameter of these follicles was smaller than those of controls in mature mice, whereas no significant difference was observed in premature mice. The canonical pathways of DEGs between control and Figla-reduced secondary follicles suggest that Figla up-regulates VDR/RXR activation and down-regulates stem cell pluripotency as well as estrogen signaling. We demonstrated for the first time that folliculogenesis of the secondary follicles of premature and mature mice may be regulated by different factors, such as Figla with its possible target genes, providing insights into optimal IVG conditions for adult and pre-pubertal females, respectively.

Basal lamina characterization in frozen-thawed and long-term grafted human prepubertal ovarian tissue

RESEARCH QUESTION

Are there differences in the composition and structure of the basal lamina surrounding follicles in prepubertal versus adult human ovarian tissue?

DESIGN

Frozen-thawed human ovarian tissue from six prepubertal and seven adult patients was divided into three fragments in each case: two for non-grafted tissue evaluation and one for long-term xenografting to mice. Collagen IV and laminin expression were investigated by immunohistochemistry before and after grafting. The basal lamina was analysed by transmission electron microscopy on frozen-thawed tissue.

RESULTS

In frozen-thawed tissue, collagen IV was significantly less expressed around prepubertal follicles than around adult follicles (primordial, P = 0.02; intermediate/growing follicles, P = 0.03), while laminin was significantly more expressed (primordial, P = 0.03; intermediate, P = 0.01). Collagen IV expression was significantly higher around prepubertal primordial follicles in grafted tissue than in non-grafted tissue, reaching similar levels to those in adult tissue. Ultrastructure analysis showed the basal lamina around follicles in prepubertal frozen-thawed tissue to be rather patchy and thinner than around adult follicles (primordial/intermediate, P = 0.001; primary, P = 0.02).

CONCLUSIONS

In frozen-thawed tissue, the basal lamina around prepubertal follicles is less mature than around adult follicles, but it becomes similar in both prepubertal and adult subjects after grafting. Grafting could therefore induce maturation of the basal lamina around prepubertal follicles.

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.

Abnormal early folliculogenesis due to impeded pyruvate metabolism in mouse oocytes†

Fetal ovarian germ cells show characteristic energy metabolism status, such as enhanced mitochondrial metabolism as well as glycolysis, but their roles in early folliculogenesis are unclear. We show here that inhibition of pyruvate uptake to mitochondria by UK5099 in organ cultures of fetal mouse ovaries resulted in repressed early folliculogenesis without affecting energy production, survival of oocytes, or meiosis. In addition, the abnormal folliculogenesis by UK5099 was partially rescued by α-ketoglutarate and succinate, intermediate metabolites in the TCA cycle, suggesting the importance of those metabolites. The expression of TGFβ-related genes Gdf9 and Bmp15 in ovarian germ cells, which are crucial for folliculogenesis, was downregulated by UK5099, and the addition of recombinant GDF9 partially rescued the abnormal folliculogenesis induced by UK5099. We also found that early folliculogenesis was similarly repressed, as in the culture, in the ovaries of a germ cell-specific knockout of Mpc2, which encodes a mitochondria pyruvate carrier that is targeted by UK5099. These results suggest that insufficient Gdf9 expression induced by abnormal pyruvate metabolism in oocytes results in early follicular dysgenesis, which is a possible cause of defective folliculogenesis in humans.

In vitro growth and maturation of primordial follicles and immature oocytes

Cryopreservation of ovarian tissue to preserve the fertility of girls and young women at high risk of sterility is now widely practiced. Pieces of cryopreserved ovarian cortex can be thawed and autografted to restore fertility, but because of the risks of reintroduction of the cancer, transplantation may not be possible for girls and women with blood-borne leukemias or cancers with a high risk of ovarian metastasis. Cryopreserved ovarian tissue contains mainly primordial follicles but also provides access to immature oocytes from small antral follicles, which may be matured in vitro to provide an additional source of mature oocytes. So in cases in which transplantation is contraindicated, fertility restoration could be safely achieved in the laboratory either by in vitro maturation (IVM) of oocytes aspirated from growing follicles or by the complete in vitro growth (IVG) and maturation (IVM) of primordial follicles to produce fertile metaphase II (MII) oocytes. The development of IVM and IVG methods to support all stages of oocytes available within ovarian tissue will maximize the potential for all patients undergoing fertility preservation.

Polycystic Ovary Syndrome: Pathophysiology, Presentation and Treatment a Mini-Review Article

Polycystic ovary syndrome (PCOS) is a common heterogeneous disorder which is known as syndrome. The term ‘syndrome’ refers to a collection of clinical features or a phenotype. The specific features of the PCOS phenotype include clinical signs of androgen excess, elevated serum androgen concentrations, irregular menses, and infertility. It is common heterogenous disorder which affects women with different clinical presentations. In the basis of this disease is hormonal imbalance, such as insulin resistance and hyperinsulinemia. This review was based on searching all the available literature in the next databases: Pubmed, ClinicalTrials, Embase, Medline Complete, Web of Science, Cochrane Library, the Chinese Science and Technology Periodical Database (VIP), WanFang Database (Chinese Ministry of Science & Technology). The search terms included hormonal and metabolic aspects, therapy of PCOS, polycystic ovary syndrome, PCOS.We included only randomized clinical intervention trials in young women published in last five years and included 12 articles in our review analysis. More research is needed to clarify the complex pathophysiology of PCOS. No single test is currently available for its diagnosis. Additionally, once diagnosis is established, the options for treatment are of limited number and effectiveness because they target only the symptoms of PCOS. Finally, patients with PCOS have higher rates of metabolic complications, such as cardiovascular disease, but their impact on mortality is not clear. Therefore, more prospective epidemiologic studies on the topic are necessary.

Building Organs Using Tissue-Specific Microenvironments: Perspectives from a Bioprosthetic Ovary

Recent research in tissue engineering and regenerative medicine has elucidated the importance of the matrisome. The matrisome, effectively the skeleton of an organ, provides physical and biochemical cues that drive important processes such as differentiation, proliferation, migration, and cellular morphology. Leveraging the matrisome to control these and other tissue-specific processes will be key to developing transplantable bioprosthetics. In the ovary, the physical and biological properties of the matrisome have been implicated in controlling the important processes of follicle quiescence and folliculogenesis. This expanding body of knowledge is being applied in conjunction with new manufacturing processes to enable increasingly complex matrisome engineering, moving closer to emulating tissue structure, composition, and subsequent functions which can be applied to a variety of tissue engineering applications.

Neurobiology of puberty and its disorders

Puberty, which in humans is considered to include both gonadarche and adrenarche, is the period of becoming capable of reproducing sexually and is recognized by maturation of the gonads and development of secondary sex characteristics. Gonadarche referring to growth and maturation of the gonads is fundamental to puberty since it encompasses increased gonadal steroid secretion and initiation of gametogenesis resulting from enhanced pituitary gonadotropin secretion, triggered in turn by robust pulsatile GnRH release from the hypothalamus. This chapter reviews the development of GnRH pulsatility from before birth until the onset of puberty. In humans, GnRH pulse generation is restrained during childhood and juvenile development. This prepubertal hiatus in hypothalamic activity is considered to result from a neurobiological brake imposed upon the GnRH pulse generator resident in the infundibular nucleus. Reactivation of the GnRH pulse generator initiates pubertal development. Current understanding of the genetics and physiology of the brake will be discussed, as will hypotheses proposed to account for timing the resurgence in pulsatile GnRH and initiation of puberty. The chapter ends with a discussion of disorders associated with precocious or delayed puberty with a focus on those with etiologies attributed to aberrant GnRH neuron anatomy or function. A pediatric approach to patients with pubertal disorders is provided and contemporary treatments for both precocious and delayed puberty outlined.

Can frozen-thawed human ovary withstand refreezing-rethawing in the form of cortical strips?

PURPOSE

The aim of this study was to elucidate whether ovarian tissue is able to withstand a double freezing-thawing procedure.

METHODS

Human ovarian cortical biopsies from 4 thawed whole ovaries were divided into 4 experimental subgroups: (a) frozen-thawed non-grafted group, (b) frozen-thawed xenografted group, (c) refrozen-rethawed non-grafted group, and (d) refrozen-rethawed xenografted group. Xenografting was performed using 8 severe combined immunodeficient mice for a total duration of 21 days. The following analyses were conducted: classic hematoxylin and eosin staining, Ki67 immunolabeling, transmission electron microscopy, Masson's green trichrome, and double CD34 immunostaining.

RESULTS

Morphologically normal preantral follicles were detected in all groups. We observed a dramatic decline of more than 65% in early preantral follicle survival rates after grafting of both frozen-thawed (p < 0.0001) and refrozen-rethawed (p < 0.0001) ovarian tissue. However, mean follicle densities remained comparable between the frozen-thawed and refrozen-rethawed non-grafted groups, as well as both grafted groups. Equivalent proportions of proliferating early preantral follicles were identified in frozen-thawed and refrozen-rethawed samples, whether the tissue was grafted or not. Furthermore, we did not observe any significant difference in atretic follicle rates between any of the four groups, and the ultrastructural quality of follicles appeared unaffected by the refreezing procedure. Similar proportions of fibrosis were noted in the frozen-thawed and refrozen-rethawed groups, irrespective of grafting. Finally, no significant differences were witnessed in terms of vascularization.

CONCLUSION

We were able to demonstrate, for the first time, that refrozen-rethawed ovarian tissue has the same functional characteristics as frozen-thawed ovarian tissue.

Adipose tissue-derived stem cells protect the primordial follicle pool from both direct follicle death and abnormal activation after ovarian tissue transplantation

PURPOSE

To investigate whether adipose tissue-derived stem cells (ASCs) protect the primordial follicle pool, not only by decreasing direct follicle loss but also by modulating follicle activation pathways.

METHODS

Twenty nude mice were grafted with frozen-thawed human ovarian tissue from 5 patients. Ten mice underwent standard ovarian tissue transplantation (OT group), while the remaining ten were transplanted with ASCs and ovarian tissue (2-step/ASCs+OT group). Ovarian grafts were retrieved on days 3 (n = 5) and 10 (n = 5). Analyses included histology (follicle count and classification), immunohistochemistry (c-caspase-3 for apoptosis and LC3B for autophagy), and immunofluorescence (FOXO1 for PI3K/Akt activation and YAP for Hippo pathway disruption). Subcellular localization was determined in primordial follicles on high-resolution images using structured illumination microscopy.

RESULTS

The ASCs+OT group showed significantly higher follicle density than the OT group (p = 0.01). Significantly increased follicle atresia (p < 0.001) and apoptosis (p = 0.001) were observed only in the OT group. In primordial follicles, there was a significant shift in FOXO1 to a cytoplasmic localization in the OT group on days 3 (p = 0.01) and 10 (p = 0.03), indicating follicle activation, while the ASCs+OT group and non-grafted controls maintained nuclear localization, indicating quiescence. Hippo pathway disruption was encountered in primordial follicles irrespective of transplantation, with nuclear YAP localized in their granulosa cells.

CONCLUSION

We demonstrate that ASCs exert positive effects on the ovarian reserve, not only by protecting primordial follicles from direct death but also by maintaining their quiescence through modulation of the PI3K/Akt pathway.

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.

Long-Term Advantages of Ovarian Reserve Maintenance and Follicle Development Using Adipose Tissue-Derived Stem Cells in Ovarian Tissue Transplantation

(1) Background: Ovarian tissue transplantation with adipose tissue-derived stem cells (ASCs) has been shown to enhance graft vascularization and increase follicle survival after a short interval of 7 days. The aim of the present study was to investigate their long-term effects on primordial follicle pool maintenance and follicle development. (2) Methods: A total of 14 severe combined immunodeficient (SCID) mice were grafted with frozen-thawed human ovarian tissue with or without ASCs. Blood was taken monthly in order to quantify the anti-Müllerian hormone (AMH) and estradiol. After 6 months, all the grafts were retrieved and sent for histology and immunolabeling (AMH, AMH receptor II, estrogen receptors α and β, and c-kit/kit ligand). (3) Results: A significant upturn was observed in AMH and estradiol plasma levels 4 months after transplantation in both grafted groups. The primordial follicle pool was better preserved in the ASC group (41.86 ± 28.35) than in the standard transplantation group (9.65 ± 17.6, p < 0.05) compared to non-grafted controls (124.7 ± 140). (4) Conclusions: The use of ASCs prior to ovarian tissue transplantation yielded a larger primordial follicle pool and more physiological follicle distribution after long-term grafting. These findings suggested that ASC use might extend the ovarian tissue lifespan.

Two Successful Deliveries after 6 and 13 Years from 10 Oocytes Vitrified for Fertility Preservation in a Then 20-Year-Old Patient with PH-Positive Acute Lymphoid Leukemia

Oocyte vitrification is one of the methods for preserving fertility of cancer patients. In 2013, we reported a successful live birth using cryopreserved oocytes from a patient who contracted Ph-positive acute lymphoid leukemia at the retrieval age of 20. In this report, we described a second live birth from the same patient. The patient visited our clinic in November 2018 hoping to utilize vitrified oocytes cryopreserved in 2007. As a result, a day 3 single eight-cell stage embryo was transferred in a hormone replacement therapy cycle. She became pregnant and gave birth to a healthy girl (2,740 g) in September 2019. This is a case report of two live births from 10 matured oocytes that had been preserved for 12 years.

Novel extra cellular-like matrices to improve human ovarian grafting

PURPOSE

To investigate if human ovarian grafting with pure virgin human recombinant collagen type-1 from bioengineered plant lines (CollPlant™) or small intestine submucosa (SIS) yields better implantation results for human ovarian tissue and which method benefits more when combined with the host melatonin treatment and graft incubation with biological glue + vitamin E + vascular endothelial growth factor-A.

METHODS

Human ovarian tissue wrapped in CollPlant or SIS was transplanted into immunodeficient mice with/without host/graft treatment. The tissue was assessed by follicle counts (including atretic), for apoptosis evaluation by terminal deoxynucleotidyl transferase assay and for immunohistochemical evaluation of neovascularization by platelet endothelial cell adhesion molecule (PECAM) expression, and for identification of proliferating granulosa cells by Ki67 expression.

RESULTS

Human ovarian tissue transplanted with CollPlant or SIS fused with the surrounding tissue and promoted neovascularization. In general, implantation with CollPlant even without additives promoted better results than with SIS: significantly higher number of recovered follicles, significantly fewer atretic follicles, and significantly more granulosa cell proliferation. Moreover, results with CollPlant alone seemed to be at least as good as those after host and graft treatments.

CONCLUSIONS

CollPlant is a biomaterial without any potential risks, and grafting ovarian tissue with CollPlant is easy and the procedure may be easily modified, with limited or no foreseeable risks, for auto-transplantation in cancer survivors. Further studies are needed using other novel methods capable of enhancing neovascularization and reducing apoptosis and follicle atresia.

Early prepubertal cyclophosphamide exposure in mice results in long-term loss of ovarian reserve, and impaired embryonic development and blastocyst quality

Background

Due to improved treatment, there is an increasing focus on the reproductive potential of survivors of childhood cancer. Cytotoxic chemotherapy accelerates the decline in the number of primordial follicles within the mammalian ovary at all ages, but effects on the developmental potential of remaining oocytes following prepubertal cancer treatment are unclear.

Objectives

To investigate whether cyclophosphamide (CY) exposure in the prepubertal period in female mice influences ovarian function and the functional competence of oocytes in adulthood.

Methods

This study used Swiss albino mice as the experimental model. Female mice were treated with 200 mg/kg CY on either postnatal day 14 (CY14), 21 (CY21) or 28 (CY28) i.e at a prepubertal and 2 young postpubertal ages. At 14 weeks of life, ovarian function, functional competence of oocytes, and embryo quality were assessed.

Results

The number of primordial follicles decreased significantly in CY14 and CY21 groups compared to control (p < 0.01). The number of oocytes from superovulated was 8.5 ± 1.4, 24.1 ± 2.9 and 26.8 ± 2.1 in CY14, CY21 and CY28 respectively which was significantly lower than control (50.2 ± 3.2; p < 0.001). In vitro culture of CY14 embryos demonstrated only 55.4% blastocyst formation (p < 0.0001) and reduced ability of inner cell mass (ICM) to proliferate in vitro (p < 0.05) at 120 and 216 h post insemination respectively. On the other hand, ICM proliferation was unaltered in 2 young postpubertal ages.

Conclusion

Our results indicate long-term effects on the developmental competence of oocytes exposed to CY in early but not adult life. These data provide a mechanism whereby long-term fertility can be impaired after chemotherapy exposure, despite the continuing presence of follicles within the ovary, and support the need for fertility preservation in prepubertal girls before alkylating agent exposure.