Fertility preservation in girls and young women

A Cross-Sectional Survey of Healthcare Professionals' Knowledge, Attitude and Current Behaviours towards Female Fertility Preservation Services within the UK

(1) Background: This study aims to establish the knowledge, attitudes and current behaviours towards female fertility preservation (FP) services amongst healthcare professionals (HCPs) in the UK. (2) Methods: An online survey was advertised publicly on the social media platform Instagram between 25 February 2021 and 11 March 2021. (3) Results: In total, 415 participants fulfilled the inclusion criteria and completed the survey. The majority of HCPs discussed FP techniques either never 39.5% (n = 164), once a year 20.7% (n = 86) or once a month 17.8% (n = 74). The majority rated their knowledge of each type of FP method as 'very poor' or 'poor' and strongly disagreed 14.2% (n = 59) or disagreed 42.2% (n = 175) with the statement they 'felt confident to counsel a patient on FP'. The majority either agreed 37.8% (n = 157) or strongly agreed 22.2% (n = 92) that it was their responsibility to discuss FP and 38.1% (n = 158) agreed or strongly agreed 19.5% (n = 81) they considered the desire for future fertility when planning treatment. The majority 87.2% (n = 362) had not experienced formal training on FP. (4) Conclusions: Discrepancies in knowledge remain regarding techniques of FP, referral pathways, awareness of facilities offering services and existing educational resources. Many HCPs recognise the importance of FP and their responsibility to initiate discussions. The knowledge that FP may not delay the treatment of cancer has also improved; however, training in FP is scarce.

Ethical, legal, social, and policy issues of ovarian tissue cryopreservation in prepubertal girls: a critical interpretive review

PURPOSE

Despite the increasing number of childhood cancer survivors, significant advances in ovarian tissue cryopreservation (OTC) technique and medical societies' recommendations, fertility preservation (FP) and FP discussions are not always offered as a standard of care in the pediatric context. The aim of this literature review is to understand what ethical, legal, social, and policy issues may influence the provision of FP by OTC in prepubertal girls with cancer.

METHODS

A critical interpretive review of peer-reviewed papers published between 2000 and January 2023 was conducted, guided by the McDougall's version of the critical interpretive synthesis (Dixon-Woods), to capture recurring concepts, principles, and arguments regarding FP by OTC for prepubertal girls.

RESULTS

Of 931 potentially relevant papers, 162 were included in our analysis. Data were grouped into seven thematic categories: (1) risks of the procedure, (2) unique decision-making issues in pediatric oncofertility, (3) counseling, (4) cultural and cost issues, and (5) disposition of cryopreserved reproductive tissue.

CONCLUSION

This first literature review focusing on ethical, legal, social, and policy issues surrounding OTC in prepubertal girls highlights concerns in the oncofertility debate. Although OTC is no longer experimental as of December 2019, these issues could limit its availability and the child's future reproductive autonomy. This review concludes that specific actions must be provided to enable the offer of FP, such as supporting families' decision-making in this unique and complex context, and providing pediatric patients universal and full access to free or highly subsidized OTC.

Leukemia inhibitory factor's effect on the growth and survival of sheep's follicles of ovarian tissue during vitrification

One of the experimental programs for fertility protection in women includes protective cryopreservation. Vitroficasion of ovarian tissue is one of the protective cryopreservation methods that use high concentrations of antifreeze and faster cooling. To reduce its complications, LIF (Leukemia inhibitory factor) was used as a pretreatment in this study. In this study, the ovaries were randomly divided into 8 groups. In NCN (without pretreatment and LIF in culture media), NCP (without pretreatment and with LIF in culture media), PCP (with pretreatment and LIF in culture media), and PCN (with pretreatment and without LIF in culture media) groups, vitrification and reversal were not performed. In the groups NVN (without pretreatment and LIF in culture media), NVP (without pretreatment and with LIF in culture media) PV, PVP (with pretreatment and LIF in culture media), and PVN (with pretreatment and without LIF in culture medium) groups, vitrification and tissue reversal were performed. All groups were cultured and histological, cellular, and molecular evaluations were performed. The results of the present study showed that LIF in the culture medium reduced the number of abnormal, primordial, primary, and secondary follicles, and DNA breakage compared to the group without LIF (P < 0.05) and increases the growth of follicles and expression of GDF9, BMP, AMH, KITLG genes (P < 0.05). The use of LIF pretreatment before vitrification and melting of sheep ovary tissue in its culture medium reduces the damage caused by it and increases the growth and development of ovarian follicles while maintaining their function.

Pre-pubertal oocytes harbor altered histone modifications and chromatin configuration

Pre-pubertal oocytes are still dormant. They are arrested in a GV state and do not undergo meiotic divisions naturally. A multitude of molecular pathways are changed and triggered upon initiation of puberty. It is not yet clear which epigenetic events occur in oocytes upon pubertal transition, and how significant these epigenetic events may be. We evaluated epigenetic marker levels in mouse pre-pubertal and post-pubertal female oocytes. In addition, we evaluated H3K9me2 levels in human oocytes collected from fertility preservation patients, comparing the levels between pre-pubertal patients and post-pubertal patients. The chromatin structure shows a lower number of chromocenters in mouse post-pubertal oocytes in comparison to pre-pubertal oocytes. All heterochromatin marker levels checked (H3K9me2, H3K27me3, H4K20me1) significantly rise across the pubertal transition. Euchromatin markers vary in their behavior. While H3K4me3 levels rise with the pubertal transition, H3K27Ac levels decrease with the pubertal transition. Treatment with SRT1720 [histone deacetylase (HDAC) activator] or overexpression of heterochromatin factors does not lead to increased heterochromatin in pre-pubertal oocytes. However, treatment of pre-pubertal oocytes with follicle-stimulating hormone (FSH) for 24 h - changes their chromatin structure to a post-pubertal configuration, lowers the number of chromocenters and elevates their histone methylation levels, showing that hormones play a key role in chromatin regulation of pubertal transition. Our work shows that pubertal transition leads to reorganization of oocyte chromatin and elevation of histone methylation levels, thus advancing oocyte developmental phenotype. These results provide the basis for finding conditions for in-vitro maturation of pre-pubertal oocytes, mainly needed to artificially mature oocytes of young cancer survivors for fertility preservation purposes.

Cell therapy for the treatment of reproductive diseases and infertility: an overview from the mechanism to the clinic alongside diagnostic methods

Infertility is experienced by 8%-12% of adults in their reproductive period globally and has become a prevalent concern. Besides routine therapeutic methods, stem cells are rapidly being examined as viable alternative therapies in regenerative medicine and translational investigation. Remarkable progress has been made in understanding the biology and purpose of stem cells. The affected pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSCs) are further studied for their possible use in reproductive medicine, particularly for infertility induced by premature ovarian insufficiency and azoospermia. Accordingly, this study discusses current developments in the use of some kinds of MSCs such as adipose-derived stem cells, bone marrow stromal cells, umbilical cord MSCs, and menstrual blood MSCs. These methods have been used to manage ovarian and uterine disorders, and each technique presents a novel method for the therapy of infertility.

Germline stem cells in human

The germline cells are essential for the propagation of human beings, thus essential for the survival of mankind. The germline stem cells, as a unique cell type, generate various states of germ stem cells and then differentiate into specialized cells, spermatozoa and ova, for producing offspring, while self-renew to generate more stem cells. Abnormal development of germline stem cells often causes severe diseases in humans, including infertility and cancer. Primordial germ cells (PGCs) first emerge during early embryonic development, migrate into the gentile ridge, and then join in the formation of gonads. In males, they differentiate into spermatogonial stem cells, which give rise to spermatozoa via meiosis from the onset of puberty, while in females, the female germline stem cells (FGSCs) retain stemness in the ovary and initiate meiosis to generate oocytes. Primordial germ cell-like cells (PGCLCs) can be induced in vitro from embryonic stem cells or induced pluripotent stem cells. In this review, we focus on current advances in these embryonic and adult germline stem cells, and the induced PGCLCs in humans, provide an overview of molecular mechanisms underlying the development and differentiation of the germline stem cells and outline their physiological functions, pathological implications, and clinical applications.

Follicle isolation methods reveal plasticity of granulosa cell steroidogenic capacity during mouse in vitro follicle growth

Follicles are the functional unit of the ovary and several methods have been developed to grow follicles ex vivo, which recapitulate key events of oogenesis and folliculogenesis. Enzymatic digestion protocols are often used to increase the yield of follicles from the ovary. However, the impact of these protocols on the outermost theca and granulosa cells, and thereby follicle function, is not well defined. To investigate the impact of enzymatic digestion on follicle function, we collected preantral follicles from CD1 mice either by enzymatic digestion (Enzy-FL) or mechanical isolation (Mech-FL) and compared follicle growth, steroidogenesis and cell differentiation within an encapsulated in vitro follicle growth system which maintains the 3D architecture of the oocyte and its surrounding somatic cells. Follicles were encapsulated in 0.5% alginate and cultured for 8 days. Compared with Enzy-FL, Mech-FL grew more rapidly and produced significantly higher levels of androstenedione, estradiol and progesterone. The expression of theca-interstitial cell marker genes, Cyp17a1, which encodes 17-hydroxylase/17, 20-lyase and catalyzes the hydroxylation of pregnenolone and progesterone to 17-hydroxypregnenolone and 17-hydroxyprogesterone, and the conversion of these products into dehydroepiandrosterone and androstenedione, and Star, which encodes a transport protein essential for cholesterol entry into mitochondria, were also higher in Mech-FL than in Enzy-FL. Mech-FL maintained an intact theca-interstitial layer on the outer edge of the follicle that phenocopied in vivo patterns as confirmed by alkaline phosphatase staining, whereas theca-interstitial cells were absent from Enzy-FL from the onset of culture. Therefore, preservation of the theca cell layer at the onset of culture better supports follicle growth and function. Interestingly, granulosa cells in the outermost layers of Enzy-FL expressed CYP17A1 by Day 4 of culture while maintaining inhibin α-subunit expression and a cuboidal nucleus. Thus, in the absence of theca-interstitial cells, granulosa cells have the potential to differentiate into androgen-producing cells. This work may have implications for human follicle culture, where enzymatic isolation is required owing to the density of the ovarian cortex.

Protective effects of human umbilical cord mesenchymal stem cell-derived conditioned medium on ovarian damage

Chemotherapeutic agents are extensively used to treat malignancies. However, chemotherapy-induced ovarian damage and reduced fertility are severe side effects. Recently, stem cell transplantation has been reported to be an effective strategy for premature ovarian insufficiency (POI) treatment, but safety can still be an issue in stem cell-based therapy. Here, we show the protective effects of human umbilical cord mesenchymal stem cell-derived conditioned medium (hUCMSC-CM) on a cisplatin (Cs)-induced ovarian injury model. hUCMSC-CM can relieve Cs-induced depletion of follicles and preserve fertility. In addition, hUCMSC-CM can decrease apoptosis of oocytes and granulosa cells induced by Cs. RNA sequencing analysis reveals the differentially expressed genes of ovaries after Cs and hUCMSC-CM treatments, including genes involved in cell apoptosis. Furthermore, we show that the granulocyte colony-stimulating factor (G-CSF)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway plays an important role in protecting granulosa cells from Cs-induced apoptosis. Together, we confirm the protective effects of hUCMSC-CM on ovarian reserve and fertility in mice treated with Cs, highlighting the remarkable therapeutic effects of hUCMSC-CM.

Application of Stem Cell Therapy for Infertility

Infertility creates an immense impact on the psychosocial wellbeing of affected couples, leading to poor quality of life. Infertility is now considered to be a global health issue affecting approximately 15% of couples worldwide. It may arise from factors related to the male (30%), including varicocele, undescended testes, testicular cancer, and azoospermia; the female (30%), including premature ovarian failure and uterine disorders; or both partners (30%). With the recent advancement in assisted reproduction technology (ART), many affected couples (80%) could find a solution. However, a substantial number of couples cannot conceive even after ART. Stem cells are now increasingly being investigated as promising alternative therapeutics in translational research of regenerative medicine. Tremendous headway has been made to understand the biology and function of stem cells. Considering the minimum ethical concern and easily available abundant resources, extensive research is being conducted on induced pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSC) for their potential application in reproductive medicine, especially in cases of infertility resulting from azoospermia and premature ovarian insufficiency. However, most of these investigations have been carried out in animal models. Evolutionary divergence observed in pluripotency among animals and humans requires caution when extrapolating the data obtained from murine models to safely apply them to clinical applications in humans. Hence, more clinical trials based on larger populations need to be carried out to investigate the relevance of stem cell therapy, including its safety and efficacy, in translational infertility medicine.

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.

Regenerative Medicine Approaches in Bioengineering Female Reproductive Tissues

Diseases, disorders, and dysfunctions of the female reproductive tract tissues can result in either infertility and/or hormonal imbalance. Current treatment options are limited and often do not result in tissue function restoration, requiring alternative therapeutic approaches. Regenerative medicine offers potential new therapies through the bioengineering of female reproductive tissues. This review focuses on some of the current technologies that could address the restoration of functional female reproductive tissues, including the use of stem cells, biomaterial scaffolds, bio-printing, and bio-fabrication of tissues or organoids. The use of these approaches could also be used to address issues in infertility. Strategies such as cell-based hormone replacement therapy could provide a more natural means of restoring normal ovarian physiology. Engineering of reproductive tissues and organs could serve as a powerful tool for correcting developmental anomalies. Organ-on-a-chip technologies could be used to perform drug screening for personalized medicine approaches and scientific investigations of the complex physiological interactions between the female reproductive tissues and other organ systems. While some of these technologies have already been developed, others have not been translated for clinical application. The continuous evolution of biomaterials and techniques, advances in bioprinting, along with emerging ideas for new approaches, shows a promising future for treating female reproductive tract-related disorders and dysfunctions.

Comparison of Oocyte and Embryo Quality Between Random Start and Controlled Ovarian Stimulation Cycles in Cancer Patients Undergoing Fertility Preservation

Conventional assisted reproductive technology (ART) cycles may delay cancer treatment and compromise survival, and also increase patients' psychological burden as a result of delayed chemotherapy. The aim of this study was to compare the success rates of random start and conventional start GnRH antagonist protocols in terms of oocyte and embryo outputs in cancer patients. Data of 111 patients with a newly diagnosed cancer who underwent ART for fertility preservation at a university-based infertility clinic between January 2010 and September 2019 were reviewed. The study group underwent random start controlled ovarian hyperstimulation (RS-COH) and the control group underwent conventional start COH (CS-COH). The main outcome measures were the number of total oocytes, MII oocytes, and embryo yield. A total of 46 patients (41.5%) underwent RS-COH and 65 (58.5%) underwent CS-COH. Baseline characteristics were similar between the groups. The most common cancer type in both groups was breast cancer (60.9% vs. 52.3%, respectively). The median duration of stimulation was significantly longer in RS-COH than in CS-COH (12 vs. 10 days; P = 0.005). The median number of MII oocytes was significantly higher in RS-COH than in CS-COH (7 vs. 5 oocytes, respectively; P = 0.020). The MII/AFC ratio was significantly higher in the RS-COH group compared to the CS-COH group (74% and 57% respectively; p = 0.02). In the linear regression analyses, RS-COH protocol did not have a significant impact on MII/AFC (standardized ß coefficient - 0.514; P = 0.289 {adjusted R² for the model = 0.779}), oocyte yield (standardized ß coefficient - 0.070; P = 0.829 {adjusted R² for the model = 0.840}), and MII rate (standardized ß coefficient - 0.504; P = 0.596 {adjusted R² for the model = 0.271}). In conclusion, RS-COH protocol is as effective as CS-COH protocols for fertility preservation in cancer patients.

Analyses of human granulosa cell vitality by fluorescence activated cell sorting after rapid cooling

In reproductive medicine, the technique of rapid cooling becomes increasingly important for the preservation of tissue and cells. In order to protect the cells, incubation in different cryopreservation solutions is essential. The speed of the cooling process also makes a pivotal contribution to the success of this method. Using Flourescence Activated Cell Sorting (FACS), we investigated the impact of an open rapid and a closed rapid cooling technique on the vitality of human granulosa cells. Furthermore, we examined effects of the different solutions used for rapid cooling and warming before and after rapid cooling. We found a significant lower proportion of vital cells after rapid cooling compared to untreated controls independently of the technique and the tube size. However, we did not find any significant differences between open and closed rapid cooling. In both, a lower proportion of vital granulosa cells were found after incubation in rapid cooling solution only compared to warming solution only. Our results lend support to the conclusion that the difference of cooling-speed between open and closed rapid cooling is, in our settings, not crucial for the success of the procedure and that cryoprotective agents in the rapid cooling solutions have a higher potential to cause severe cell damage than agents used for warming.

Bioengineering the ovary to preserve and reestablish female fertility

Different bioengineering strategies can be presently adopted and have been shown to have great potential in the treatment of female infertility and ovarian dysfunction deriving from chemotherapy, congenital malformations, massive adhesions as well as aging and lifestyle. One option is transplantation of fresh or cryopreserved organs/fragments into the patient. A further possibility uses tissue engineering approaches that involve a combination of cells, biomaterials and factors that stimulate local ability to regenerate/ repair the reproductive organ. Organ transplant has shown promising results in large animal models. However, the source of the organ needs to be identified and the immunogenic effects of allografts remain still to be solved before the technology may enter the clinical practice. Decellularization/ repopulation of ovary with autologous cells or follicles could represent an interesting, still very experimental alternative. Here we summarize the recent advancements in the bioengineering strategies applied to the ovary, we present the principles for these systems and discuss the advantages of these emerging opportunities to preserve or improve female fertility.

In vitro survival of follicles in prepubertal ewe ovarian cortex cryopreserved by slow freezing or non-equilibrium vitrification

PURPOSE

Vitrification is a well-accepted fertility preservation procedure for cryopreservation of oocytes and embryos but little is known regarding ovarian tissue, for which slow freezing is the current convention. The aim of the present study was to assess the efficiency of non-equilibrium vitrification compared to conventional slow freezing for ovarian cortex cryopreservation.

METHODS

Using prepubertal sheep ovaries, the capacity of the tissue to sustain folliculogenesis following cryopreservation and in vitro culture was evaluated. Ovarian cortex fragments were cultured in wells for 9 days, immediately or after cryopreservation by conventional slow freezing or non-equilibrium vitrification in straws. During culture, follicular populations within cortex were evaluated by histology and immunohistochemistry for PCNA and TUNEL. Steroidogenic activity of the tissue was monitored by assay for progesterone and estradiol in spent media.

RESULTS

No significant differences in follicle morphology, PCNA, or TUNEL labeling were observed between cryopreservation methods at the initiation of culture. Similar decreases in the proportion of primordial follicle population, and increases in the proportion of growing follicles, were observed following culture of fresh or cryopreserved ovarian tissue regardless of cryopreservation method. At the end of culture, PCNA and TUNEL-positive follicles were not statistically altered by slow freezing or vitrification in comparison to fresh cultured fragments.

CONCLUSIONS

Overall, for both cryopreservation methods, the cryopreserved tissue showed equal capacity to fresh tissue for supporting basal folliculogenesis in vitro. Taken together, these data confirm that both non-equilibrium vitrification and slow-freezing methods are both efficient for the cryopreservation of sheep ovarian cortex fragments.

A review of factors affecting patient fertility preservation discussions & decision-making from the perspectives of patients and providers

Women undergoing cancer treatments and their healthcare providers encounter challenges in fertility preservation (FP) discussions and decision-making. A systematic review of qualitative research was conducted to gain in-depth understanding of factors influencing FP discussions and decision-making. Major bibliographic databases and grey literature in English from 1994 to 2016 were searched for qualitative research exploring patient/provider perspectives on barriers and facilitators to FP decision-making. Two researchers screened article titles, abstracts and full-texts. Verbatim data on research questions, study methodology, participants, findings and discussions of findings were extracted. Quality assessment and thematic analysis were conducted. The search yielded 74 studies dating from 2007 onwards; 29 met the inclusion criteria. Analysis revealed three types of barriers: (a) FP knowledge, skills and information deficits contributed to discomfort for providers and discontent for patients; (b) psychosocial factors and clinical issues influenced providers' practices around FP discussions and patients' decision-making; and (c) material, social and structural factors (e.g., lack of resources and accessibility) posed challenges to FP discussions. Potential facilitators to FP discussions and decision-making were also identified. A discussion of ways to improve physician's knowledge and facilitate women's decision-making and access to FP is presented, along with areas for policy development and further research.

Repetitive Maturation of Oocytes From Non-Stimulated Xenografted Ovarian Tissue From a Prepubertal Patient Indicating the Independence of Human Ovarian Tissue

Introduction

Modern anti-cancer strategies have distinctly increased survival rates; nevertheless, often accompanied by sterility. Currently, the only option for preserving fertility in prepubertal females is to cryopreserve ovarian tissue and re-transplant frozen-thawed tissue to restore fertility after treatment. Our aim was to report the occurrence of repetitive antral follicle formation and oocyte maturation in a prepubescent ovarian tissue xenograft without exogenous hormone stimulation.

Material and Methods

Frozen-thawed ovarian tissue from a 6-year-old patient suffering from nephroblastoma was xenotransplanted in oophorectomized severe combined immunodeficiency (SCID) mice to evaluate follicle development.

Ergebnisse

Repetitive follicle development to the antral stage occurred in the same xenograft of prepubertal ovarian tissue without exogenous hormone administration; 37 days after retrieving a maturing oocyte (this first retrieval has been previously published), another, completely mature oocyte was harvested from the xenograft. Subsequent histological evaluation of the grafted tissue showed primordial follicles, nearly all stages of developing follicles, as well as large atretic ones. Many clusters with dormant primordial follicles were also present.

Conclusion

Xenotransplanted prepubertal ovarian tissue has the potential for repetitive oocyte retrieval cycles without administering exogenous hormones. The results indicate that the human ovarian tissue might be able to synchronize the hypothalamus-hypophysis-axes of the mouse to the physiological human cycle; this should be investigated in future studies.

Double ovarian stimulation (DuoStim) protocol for fertility preservation in female oncology patients

This article describes a revised ovarian stimulation protocol (DuoStim) for fertility preservation in female oncology patients which aims to maximise the number of gametes obtained with subsequent improvement in cumulative birth rate, without delaying cancer treatment. Ten patients diagnosed with malignancy between September 2014 and October 2015 were included. The patients were treated with the DuoStim protocol, undergoing two consecutive ovarian stimulation cycles and two oocyte retrievals. The primary outcome was the number of oocytes collected and vitrified during each oocyte retrieval and in total. The protocol was evaluated regarding medical risk and patients' feedback. During the first oocyte collection 81 oocytes (61 metaphase II) were retrieved (mean = 8.1; range = 1-13) and during the second oocyte collection 82 oocytes (67 metaphase II) were retrieved (mean= 8.2; range = 1-19). A total of 163 oocytes (128 metaphase II) were collected (mean = 16.3; range = 6-32) and cancer treatment was not delayed for any of these patients. There were no cases of ovarian hyperstimulation syndrome recorded. More patients and long-term follow-up is needed to assess the efficacy and safety of the DuoStim protocol. However, these early results are encouraging, demonstrating an increase in number of mature oocytes retrieved during ovarian stimulation for oncology patients, without delaying cancer treatment.

Irinotecan metabolite SN38 results in germ cell loss in the testis but not in the ovary of prepubertal mice

STUDY QUESTION

Does the Irinotecan metabolite 7-ethyl-10-hydroxycamptothecan (SN38) damage the gonads of male and female prepubertal mice?

SUMMARY ANSWER

The Irinotecan metabolite SN38 reduces germ cell numbers within the seminiferous tubules of mouse testes at concentrations that are relevant to cancer patients, while in contrast it has little if any effect on the female germ cell population.

WHAT IS KNOWN ALREADY

Little is known about the role of the chemotherapeutic agent Irinotecan on female fertility, with only one article to date reporting menopausal symptoms in perimenopausal women treated with Irinotecan, while no data are available either on adult male fertility or on the impact of Irinotecan on the subsequent fertility of prepubertal cancer patients, female or male.

STUDY DESIGN SIZE, DURATION

Male and female gonads were obtained from postnatal day 5 C57BL/6 mice and exposed in vitro to a range of concentrations of the Irinotecan metabolite SN38: 0.002, 0.01, 0.05, 0.1 or 1 µg ml^–1 for the testis and 0.1, 1, 2.5 or 5 µg ml^–1 for the ovary, with treated gonads compared to control gonads not exposed to SN38. SN38 was dissolved in 0.5% dimethyl sulfoxide, with controls exposed to the same concentration of diluent. The number of testis fragments used for each analysis ranged between 3 and 9 per treatment group, while the number of ovaries used for each analysis ranged between 4 and 12 per treatment group.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Neonatal mouse gonads were developed in vitro, with tissue analysed at the end of the 4–6 day culture period, following immunofluorescence or hematoxylin and eosin staining. Statistical analyses were performed using one-way ANOVA followed by Bonferroni post-hoc test for normally distributed data and Kruskal-Wallis test followed by Dunns post-test for non-parametric data.

MAIN RESULTS AND THE ROLE OF CHANCE

Abnormal testis morphology was observed when tissues were exposed to SN38, with a smaller seminiferous tubule diameter at the highest concentration of SN38 (1 µg ml⁻¹, p < 0.001 versus control) and increased number of Sertoli cell-only tubules at the two highest concentrations of SN38 (0.1 µg ml⁻¹, p < 0.001; 1 µg ml⁻¹, p < 0.0001, both versus control). Within seminiferous tubules, a dose response decrease was observed in both germ cell number (mouse vasa homologue (MVH)-positive cells) and in proliferating cell number (bromodeoxyuridine (BrdU)-positive cells), with significance reached at the two highest concentrations of SN38 (0.1 µg ml⁻¹, p < 0.01 for both; 1 µg ml⁻¹, p < 0.001-MVH, p < 0.01-BrdU; all versus control). No change was seen in protein expression of the apoptotic marker cleaved caspase 3. Double immunofluorescence showed that occasional proliferating germ cells were present in treated testes, even after exposure to the highest drug concentration. When prepubertal ovaries were treated with SN38, no effect was seen on germ cell number, apoptosis or cell proliferation, even after exposure to the highest drug concentrations.

LIMITATIONS REASONS FOR CAUTION

As with any study using in vitro experiments with an experimental animal model, caution is required when extrapolating the present findings to humans. Differences between human and mouse spermatogonial development also need to be considered when assessing the effect of chemotherapeutic exposure. However, the prepubertal testes and ovaries used in the present studies contain germ cell populations that are representative of those found in prepubertal patients, and experimental tissues were exposed to drug concentrations within the range found in patient plasma.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings demonstrate that the prepubertal mouse ovary is relatively insensitive to exposure to the Irinotecan metabolite SN38, while it induces a marked dose-dependent sensitivity in the testicular germ cell population. The study identifies the importance of further investigation to identify the risk of infertility in young male cancer patients treated with Irinotecan.

LARGE SCALE DATA

None.

STUDY FUNDING AND COMPETING INTEREST(S)

Work supported by Medical Research Grant (MRC) grant G1002118 and Children with Cancer UK grant 15-198. The authors declare that there is no conflict of interest that could prejudice the impartiality of the present research.

[Ovocyte vitrification: a tool for the future]

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

The first 50 live births after autologous oocyte vitrification in France

PURPOSE

The study aims to describe the newborn health parameters of the 50 first children conceived after autologous oocyte vitrification in France.

METHODS

The 50 children born after autologous oocyte vitrification/warming cycle (VAO children) have been retrospectively compared with 364 children conceived by micromanipulation using freshly recovered non-vitrified oocytes (ICSI children). Children included in the study were born between 2011 and 2015. Maternal characteristics (age, body mass index, smoking habits), obstetric outcomes (diabetes, hypertension, placenta previa, parity, mode of delivery), and perinatal outcome (twinning, sex, birth weight, macrosomia, birth defects) were analyzed. The generalized estimating equation for correlated data was performed to evaluate perinatal outcomes and caesarean section.

RESULTS

No statistically significant difference was found between VAO children and ICSI children, even after adjusting confounding factors (low birth weigh odds ratio (OR) 0.8, 95 % confident interval (CI) 0.3-2.2, adjusted (AOR) 0.5, 95 % CI 0.2-1.7; large for gestational age OR 1.5, 95 % CI 0.3-7.0, AOR 1.6, 95 % CI 0.3-7.5; birth defects OR 0.4, 95 % CI 0.1-3.2, AOR 0.5, 95 % CI 0.1-3.7; caesarean section OR 1.8, 95 % CI 0.9-3.4, AOR 1.8, 95 % CI 0.9-3.7).

CONCLUSIONS

According to our results, newborn health parameters of children conceived in our center by micromanipulation using vitrified/warmed autologous oocytes seem not to be different from children born after micromanipulation on freshly recovered oocytes.

Morphokinetics analysis of embryos derived from vitrified/warmed oocytes

PURPOSE

Oocyte vitrification is a worldwide used technique that has proved its worth. Although it was shown not to alter oocyte integrity, a recent study concluded that it may affect oocyte embryo development. As the morphology and kinetics of embryos derived from sibling fresh and vitrified oocytes have not been described previously, the present study evaluates cleavage rate, blastomeres size, fragmentation rate, and blastocyst formation in vitrified/warmed oocyte derived embryos (VODE) as compared with sibling fresh oocytes derived embryos (FODE).

METHODS

This investigation included 90 infertility cases displaying large cohort of mature oocytes at pick up, divided into 2 groups after denudation. A part of oocytes underwent ICSI while others were vitrified. Oocyte warming cycles were performed when no pregnancy was achieved using fresh eggs. Zygote to blastocyst development was recorded prospectively in an image database up to day 5.

RESULTS

VODE did not show major difference as compared with FODE in terms of cleavage rate, number of blastomeres, fragmentation rate, and blastomeres size. Furthermore, percentage of morulae at day 4 and blastocysts at day 5 are not affected by oocyte vitrification.

CONCLUSION

Although our results show that embryo development is not altered by oocyte vitrification, offspring follow-up is essential to exclude any adverse developmental effect of the technique.

Pubertal induction in hypogonadism: Current approaches including use of gonadotrophins

Primary disorders of the gonad or those secondary to abnormalities of the hypothalamic pituitary axis result in hypogonadism. The range of health problems of childhood and adolescence that affect this axis has increased, as most children now survive chronic illness, but many have persisting deficits in gonadal function as a result of their underlying condition or its treatment. An integrated approach to hormone replacement is needed to optimize adult hormonal and bone health, and to offer opportunities for fertility induction and preservation that were not considered possible in the past. Timing of presentation ranges from birth, with disorders of sexual development, through adolescent pubertal failure, to adult fertility problems. This review addresses diagnosis and management of hypogonadism and focuses on new management strategies to address current concerns with fertility preservation. These include Turner syndrome, and fertility presevation prior to childhood cancer treatment. New strategies for male hormone replacement therapy that may impinge upon future fertility are emphasized.

Modern radiation therapy and potential fertility preservation strategies in patients with cervical cancer undergoing chemoradiation

Young patients with cervical cancer who undergo chemoradiation might be interested in fertility preservation, not only dependent upon the use of a gestational carrier as maybe achieved by the use of ovarian transposition and cryo-conservation of oocytes or ovarian tissue, but may prefer to carry pregnancy to term after cancer treatment. The latter approach is a non-established concept needing both modern radiation therapy approaches as well as modifications -if at all possible- in current recommendations for target volume delineation to spare dose to the unaffected uterus. Future strategies to serve selected patients in this respect should only be conducted in prospective clinical evaluations and are critically discussed in this article.

Challenges and considerations in optimizing ovarian stimulation protocols in oncofertility patients

The scope of cancer treatment in women of childbearing age has changed in the last decade. Fertility preservation is no longer an afterthought but central to multi-disciplinary cancer treatment planning and should be addressed due to the cytotoxic effects of cancer therapy. However, oncology patients present as a unique treatment challenge as the physician must balance the urgency of fertility preservation with the risks of delaying cancer therapy. Controlled ovarian stimulation (COS) is routinely applied in assisted reproductive technology but can be contraindicated in women with estrogen-receptor-positive tumors. This paper reviews some of the challenges to consider when using COS and newer stimulation protocols to minimize risks and optimize outcomes in oncofertility patients.

Ovarian tissue cryopreservation followed by controlled ovarian stimulation and pick-up of mature oocytes does not impair the number or quality of retrieved oocytes

Background

The objective of this study was to evaluate the feasibility of fertility preservation in cancer patients by combined bilateral ovarian cortex cryopreservation and embryo freezing.

Methods

This was a cohort-controlled study in a university hospital center. Sixteen patients with a recent cancer diagnosis were included in the study. They all consented to fertility preservation by a combined technique: ovarian tissue cryopreservation (OTC) followed by ovarian stimulation for in vitro fertilization (IVF) and embryo freezing. The control group included 100 women of the same age undergoing IVF for male factor infertility.

Results

The mean number of metaphase II oocytes was 8.3 per patient (±7.7) and was not statistically different from the control group (8.1 ± 5.6). The mean number of good quality embryos obtained was not statistically different in the 2 groups (4.2 versus 4.4).

Conclusion

OTC before embryo freezing does not impair the number or quality of cryopreserved embryos, but increases fertility preservation potential.

In vitro maturation of human oocytes: Its role in infertility treatment and new possibilities

IVM refers to the maturation of immature oocytes in culture after their recovery from small antral follicles at the stage prior to selection and dominance. IVM requires little or no FSH in vivo and has been proposed as an alternative to conventional IVF, since it reduces the primary adverse effects caused by controlled ovarian stimulation, including the ovarian hyperstimulation syndrome. Moreover, IVM is a promising option for cases for which no standard protocol is suitable, such as FSH resistance, contraindications for ovarian stimulatory drugs, and the need for urgent fertility preservation. Recently, IVM has been used in women with regular cycles and normal ovaries. However, the pregnancy rate following IVM is suboptimal compared with that of conventional IVF, indicating that further studies to optimize the protocol and the culture conditions are warranted.

Spontaneous antral follicle formation and metaphase II oocyte from a non-stimulated prepubertal ovarian tissue xenotransplant

BACKGROUND

Current strategies in cancer treatment have markedly increased the rates of remission and survival for cancer patients, but are often associated with subsequent sterility. While there are various options available to an adult female depending on the patient's particular situation, the only realistic option for preserving fertility in prepubertal females is to cryopreserve ovarian tissue. This is the first report of a morphologically mature oocyte collected from non-stimulated prepubertal ovarian tissue xenotransplants.

METHODS

Ovarian tissue from a 6 year old patient suffering from nephroblastoma was removed and cryopreserved for fertility preservation. The frozen-thawed ovarian tissue fragments were xenotransplanted to bilaterally oophorectomized severe combined immunodeficiency (SCID) mice to assess follicle development.

RESULTS

Antral follicle formation occurred post-xenotransplantation in a single ovarian fragment without exogenous hormone stimulation. A morphologically maturing oocyte was harvested from these follicles.

CONCLUSIONS

Prepubertal human ovarian follicles and oocytes can be matured after xenotransplantation even without exogenous hormone stimulation. These results indicate that tissue collected from prepubertal patients can support fertility in cancer survivors.

The importance of fertility preservation in cancer patients

The potential risks of anti-cancer therapy for male and female fertility are well understood, yet evidence suggests that fewer patients than predicted actually preserve their fertility before therapy begins. Studies of post-pubertal males and females suggest that the approach of health professionals in oncology is vital in facilitating successful sperm and egg banking. For men, this seems to be compounded by a general lack of understanding about their personal risk of infertility. Those involved in delivering anticancer therapy therefore have a vital role to play in providing timely information and facilitating efficient referral to fertility services. In the future, this is likely to become more important if new fertility preservation strategies such as ovarian and testicular tissue banking become more routinely used, with implications for both pre- and post-pubertal individuals.

Cyclophosphamide triggers follicle activation and "burnout"; AS101 prevents follicle loss and preserves fertility

Premature ovarian failure and infertility are major side effects of chemotherapy treatments in young cancer patients. A more thorough understanding of the mechanism behind chemotherapy-induced follicle loss is necessary to develop new methods to preserve fertility in these patients. We show that the alkylating agent cyclophosphamide (Cy) activates the growth of the quiescent primordial follicle population in mice, resulting in loss of ovarian reserve. Despite the initial massive apoptosis observed in growing, though not in resting, follicles of Cy-treated mice, differential follicle counts demonstrated both a decrease in primordial follicles and an increase in early growing follicles. Immunohistochemistry showed that granulosa cells were undergoing proliferation. Analysis of the phosphatidylinositol 3-kinase signaling pathway demonstrated that Cy increased phosphorylation of proteins that stimulate follicle activation in the oocytes and granulosa cells. Coadministration of an immunomodulator, AS101, reduced follicle activation, thereby increasing follicle reserve and rescuing fertility after Cy, and also increased the efficacy of Cy against breast cancer cell lines. These findings suggest that the mechanism in Cy-induced loss of ovarian reserve is accelerated primordial follicle activation, which results in a "burnout" effect and follicle depletion. By preventing this activation, AS101 shows potential as an ovarian-protective agent, which may be able to preserve fertility in female cancer patients.

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

STUDY QUESTION

Do the ovarian follicles of children and adolescents differ in their morphology and in vitro growth potential from those of adults?

SUMMARY ANSWER

Pre-pubertal ovaries contained a high proportion of morphologically abnormal non-growing follicles, and follicles showed reduced capacity for in vitro growth.

WHAT IS KNOWN ALREADY

The pre-pubertal ovary is known to contain follicles at the early growing stages. How this changes over childhood and through puberty is unknown, and there are no previous data on the in vitro growth potential of follicles from pre-pubertal and pubertal girls.

STUDY DESIGN, SIZE, DURATION

Ovarian biopsies from five pre-pubertal and seven pubertal girls and 19 adult women were analysed histologically, cultured in vitro for 6 days, with growing follicles then isolated and cultured for a further 6 days.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ovarian biopsies were obtained from girls undergoing ovarian tissue cryopreservation for fertility preservation, and compared with biopsies from adult women. Follicle stage and morphology were classified. After 6 days in culture, follicle growth initiation was assessed. The growth of isolated secondary follicles was assessed over a further 6 days, including analysis of oocyte growth.

MAIN RESULTS AND THE ROLE OF CHANCE

Pre-pubertal ovaries contained a high proportion of abnormal non-growing follicles (19.4 versus 4.85% in pubertal ovaries; 4004 follicles analysed; P = 0.02) characterized by indistinct germinal vesicle membrane and absent nucleolus. Follicles with this abnormal morphology were not seen in the adult ovary. During 6 days culture, follicle growth initiation was observed at all ages; in pre-pubertal samples there was very little development to secondary stages, while pubertal samples showed similar growth activation to that seen in adult tissue (pubertal group: P = 0.02 versus pre-pubertal, ns versus adult). Isolated secondary follicles were cultured for a further 6 days. Those from pre-pubertal ovary showed limited growth (P < 0.05 versus both pubertal and adult follicles) and no change in oocyte diameter over that period. Follicles from pubertal ovaries showed increased growth; this was still reduced compared with follicles from adult women (P < 0.05) but oocyte growth was proportionate to follicle size.

LIMITATIONS, REASONS FOR CAUTION

These data derive from only a small number of ovarian biopsies, although large numbers of follicles were analysed. It is unclear whether the differences between groups are related to puberty, or just age.

WIDER IMPLICATIONS OF THE FINDINGS

These findings show that follicles from girls of all ages can be induced to grow in vitro, which has important implications for some patients who are at high risk of malignant contamination of their ovarian tissue. The reduced growth of isolated follicles indicates that there are true intrafollicular differences in addition to potential differences in their local environment, and that there are maturational processes occurring in the ovary through childhood and adolescence, which involve the loss of abnormal follicles, and increasing follicle developmental competence.

Study funding/competing interest(s)

Funded by MRC grants G0901839 and G1100357. No competing interests.

[Fertility preservation in children and teenagers with cancer]

Given the excellent survival rate of children and teenagers treated for cancer, careful should be given in order to minimize long-term late effects of treatments and to improve quality of life. In this regard, fertility preservation is particularly important. Age, sex and concomitant therapies have an impact on the level of risk of hypofertility, with a stronger risk for chemotherapeutic regimens including alkylating agents, and gonads or hypothalamo-pituitary axis radiotherapy. Assessment of gonadotoxic impact of treatment strategy and fertility preservation techniques are crucial for limiting late effects. The objective of this literature review is to develop guidance for pediatric oncologists and hematologists relative to fertility preservation methods, in children and teenagers receiving gonadotoxic treatment. Specific follow-up after treatment is also proposed.

Acute effects of pelvic irradiation on the adult uterus revealed by dynamic contrast-enhanced MRI

OBJECTIVE

Pelvic radiation therapy (RT) can influence fertility in female rectal cancer survivors. Data regarding its effects on the adult uterus are scant. This study aims to evaluate the uterus before and after RT, using dynamic contrast-enhanced MRI.

METHODS

Eligible patients (n=10) received RT for rectal cancer, had an intact uterus and underwent dynamic contrast-enhanced MRI before and after RT. Seven patients were pre-menopausal.

RESULTS

Patients received pelvic RT (median, 50.2 Gy) with concurrent 5-fluorouracil. Five patients were treated with intensity modulated RT (IMRT) and five with a three-field technique. The median D95 of the uterus was 30 Gy; D05 was 48 Gy; and V95 was 97%. The median cervical D95 was 45 Gy; D05, 50 Gy; and V95, 100%. Cervical dose was higher with IMRT than with three-field plans (p≤0.038). On T2 MRI, the junctional zone was visible in nine patients before and in one after RT (p=0.001). Median cervical length (2.3 vs 3.0 cm) and endometrial thickness (2.6 vs 5.9 mm) were reduced after RT (p≤0.008). In pre-menopausal patients, the volume transfer constant, K(trans), (0.069 vs 0.195, p=0.006) and the extracellular extravascular volume fraction, V(e), (0.217 vs 0.520, p=0.053) decreased.

CONCLUSION

Pelvic RT significantly affected uterine anatomy and perfusion. Cervical dose was higher with IMRT than three-field plans, but no attempt was made to constrain the dose.

ADVANCES IN KNOWLEDGE

Pelvic RT significantly affects the adult uterus. These findings are crucial to understand the potential consequences of RT on fertility, and they lay the groundwork for further prospective studies.

Ovarian stimulation in cancer patients

The patients referred for fertility preservation owing to a malignant disease do not represent the typical population of subfertile patients treated in IVF units. Cancer may affect multiple tissues throughout the body and can result in a variety of complications during controlled ovarian stimulation. Determination of the controlled ovarian stimulation protocol and gonadotropin dose for oocyte/embryo cryopreservation requires an individualized assessment. This review highlights the new protocols that are emerging to reduce time constraints and emphasizes management considerations to decrease complications.

Ovarian stem cells--potential roles in infertility treatment and fertility preservation

One of the principal beliefs in reproductive biology is that women have a finite ovarian reserve, which is fixed from the time they are born. This theory has been questioned recently by the discovery of ovarian stem cells which are purported to have the ability to form new oocytes under specific conditions post-natally. Almost a decade after their discovery, ovarian, or oogonial, stem cells (OSCs) have been isolated in mice and humans but remain the subject of much debate. Studies in mice have shown that these cells can be cultured to a mature oocyte stage in vitro, and when injected into germ-cell depleted ovary they can form follicles and have resulted in the birth of healthy offspring. There are few data from human OSCs but this finding would open the door to novel fertility preservation strategies for women with both age-related and premature ovarian insufficiency (POI). As the number of girls and young women surviving cancer increases worldwide, POI secondary to gonadotoxic treatments, such as chemotherapy, is becoming more common. The ideal fertility preservation approach would prevent delays in commencing life-saving treatment and avoid transplanting malignant cells back into a woman after treatment: OSCs may offer one route to achieving this. This review summarises our current understanding of OSCs and discusses their potential clinical application in infertility treatment and fertility preservation.

[Fertility preservation among patients with cancer: report of a French regional practical experience]

OBJECTIVE

Improvement in cancer treatments has led to reconsider the importance of quality of life after cancer, especially concerning maintening the potential of fertility since it is often altered after healing. Our objective was to estimate the knowledge and practices of the physicians in the field of Oncology in a French Region (Provence Alpes- Côte d'Azur).

PATIENTS AND METHOD

Prospective survey, conducted between January and April 2012, amongst oncologists working in Provence Alpes Côte d'Azur region, through questionnaires distributed during multidisciplinary meetings in oncology.

RESULTS

Among 225 replies, 54% of the physicians had sent no patient to any oncofertility consultation during the previous six months (n=120). Besides, 33% of the oncologists (n=68) declared they had difficulties in addressing their patients to oncofertility consultation, and 58% of them (n=39) considered they lacked information on techniques and indications of fertility preservation.

CONCLUSION

This study provides an estimation of the current practices in PACA region concerning oncofertility and underlines the physicians' need of information. In this context, the regional oncology network has set up a regional network « cancer and fertility » in order to facilitate the access to fertility preservation prior to any potentially sterilizing treatment for all patients.

Adolescent urologic oncology: current issues and future directions

Recent Surveillance Epidemiology and End Results (SEER) data indicate that the annual cancer incidence in adolescents is higher than in children, and is on the rise. However, the amount of attention, research funding, and therapeutic progress made in the adolescent oncology population pales in comparison with that of pediatric oncology. Issues of adolescent oncology have only recently been acknowledged by leaders in the field, and current efforts now focus on raising awareness of this unique patient group. In urology, there have been many gains made in pediatric urologic oncology, most notably in Wilms tumor and genitourinary rhabdomyosarcoma (genitourinary [GU] rhabdomyosarcoma [RMS]); however, there has been little to no progress in the adolescent population. In general, adolescent cancer represents the interface between pediatric and adult oncology. Similarly, adolescent urologic oncology must be approached as a distinct entity because of the unique disease processes, treatment-related comorbidities, and psychosocial issues. This article will serve to review the most pertinent adolescent urologic oncologic diagnoses (testicular germ call malignancy, the second peak of the bimodal age distribution of GU-RMS, and adolescent renal malignancies). Also, we focus on such issues as the therapeutic impact on fertility, radiation exposure during therapy, and surveillance, risk of secondary malignancy, the long-term impact of chemotherapy, and the psychosocial burden of cancer in this population. Lastly, we highlight future directions and the foreseeable obstacles towards achieving the same research and therapeutic success enjoyed in pediatric urologic oncology.

Fertility after breast cancer

Breast cancer is the most common tumor in childbearing women. In the last decades, considerable improvement in breast cancer-related death has been achieved with adjuvant therapies (chemotherapy, endocrine and targeted therapies, radiotherapy) but at cost of significant long-term sequels, including infertility. Reproductive issues are of great importance to young women, in particular for those who did not complete their families before breast cancer diagnosis: patients should be adequately informed at the time of diagnosis about the risk of infertility and the available methods for fertility preservation. This review will focus on incidence and impact of infertility secondary to breast cancer treatment, the available options for ovarian function preservation, including embryo and oocyte cryopreservation, ovarian tissue cryopreservation, and ovarian suppression with gonadotropin-releasing hormone agonists. We will also discuss the optimal time of subsequent pregnancy, the potential risks for the mother and the fetus, and the impact of therapies on breastfeeding.

Apoptosis of human ovarian tissue is not increased by either vitrification or rapid cooling

This study evaluated the incidence of morphological changes, as assessed by light microscopy, and apoptosis in vitrified and rapidly cooled human ovarian tissue. Apoptosis was assessed 30 min and 24h after warming using transmission electron microscopy, terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) assay and DNA fragmentation, as determined by gel electrophoresis. The results showed no significant changes in morphology, chromatin condensation, DNA fragmentation or TUNEL-positive cells in follicles attributable to cryopreservation or exposure to the cryoprotectant solutions alone. In conclusion, the cryopreservation protocols did not affect the incidence of apoptosis and either protocol could be an alternative to slow cooling of ovarian tissue. This study evaluated the incidence of morphological changes, as assessed by light microscopy, and apoptosis in human ovarian tissue cryopreserved using two different methods, i.e. vitrification and rapid cooling. Apoptosis was assessed in tissue 30 min and 24h after warming using transmission electron microscopy and terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL) assay and DNA fragmentation as determined by gel electrophoresis. The results showed no significant changes in morphology, chromatin condensation, DNA fragmentation or TUNEL-positive cells in follicles attributable to cryopreservation or exposure to the cryopreservation solutions alone. In conclusion, the cryopreservation protocols did not affect the incidence of apoptosis in human ovarian tissue and either protocol could be an alternative to slow cooling for the preservation of ovarian tissue.

How do chemotherapeutic agents damage the ovary?

BACKGROUND

Chemotherapy treatment in premenopausal women is associated with an increased risk of premature ovarian failure (POF) but the exact mechanism through which this occurs is uncertain. In this review we examine the current evidence for the direct action of chemotherapeutic agents on the ovary and discuss possible molecular pathways through which follicle loss may occur.

METHODS

A systemic search of the databases, PubMed and Google Scholar, was made for all English language articles through to 2011 in each subject area discussed.

RESULTS

POF results from the loss of primordial follicles but this is not necessarily a direct effect of the chemotherapeutic agents. Instead, the disappearance of primordial follicles could be due to an increased rate of growth initiation to replace damaged developing follicles. Likewise, the loss of oocytes need not necessarily be a direct result of damage: evidence suggests that chemotherapy drugs can also induce oocyte death indirectly via damage to somatic cells. Specific molecular mechanisms and likely ovarian targets are discussed for some of the anti-cancer drugs most commonly used to treat premenopausal women. Finally, we consider current and prospective methods of preserving fertility.

CONCLUSIONS

It is likely that different chemotherapeutic drugs act through a range of mechanisms and on different target cells. More research into the cellular mechanisms underpinning chemotherapy-induced follicle loss could lead to the generation of treatments specifically designed to prevent POF.