Ovarian tissue cryopreservation and transplantation in cancer patients

Prospective solutions to ovarian reserve damage during the ovarian tissue cryopreservation and transplantation procedure

Birth rates continue to decline as more women experience fertility issues. Assisted reproductive technologies are available for patients seeking fertility treatment, including cryopreservation techniques. Cryopreservation can be performed on gametes, embryos, or gonadal tissue and can be used for patients who desire to delay in vitro fertilization treatment. This review focuses on ovarian tissue cryopreservation, the freezing of ovarian cortex containing immature follicles. Ovarian tissue cryopreservation is the only available treatment for the restoration of ovarian function in patients who undergo gonadotoxic treatments, and its wide adoption has led to its recent designation as "no longer experimental" by the American Society for Reproductive Medicine. Ovarian tissue cryopreservation and subsequent transplantation can restore native endocrine function and can support the possibility of pregnancy and live birth for the patient. Importantly, there are multiple steps in the procedure that put the ovarian reserve at risk of damage. The graft is highly susceptible to ischemic reperfusion injury and mass primordial follicle growth activation, resulting in a "burnout" phenomenon. In this review, we summarize current efforts to combat the loss of primordial follicles in grafts through improvements in freeze and thaw protocols, transplantation techniques, and pharmacologic adjuvant treatments. We conducted a review of the literature, with emphasis on emergent research in the last 5 years. Regarding freeze and thaw protocols, we discuss the widely accepted slow freezing approach and newer vitrification protocols. Discussion of improved transplantation techniques includes consideration of the transplantation location of the ovarian tissue and the importance of graft sites in promoting neovascularization. Finally, we discuss pharmacologic treatments being studied to improve tissue performance postgraft. Of note, there is significant research into the efficacy of adjuvants used to reduce ischemic injury, improve neovascularization, and inhibit hyperactivation of primordial follicle growth activations. Although the "experimental" label has been removed from ovarian tissue cryopreservation and subsequent transplantation, there is a significant need for further research to better understand sources of ovarian reserve damage to improve outcomes. Future research directions are provided as we consider how to reach the most hopeful results for women globally.

Pronuclear transfer rescues poor embryo development of in vitro-grown secondary mouse follicles

STUDY QUESTION

Is pronuclear transfer (PNT) capable of restoring embryo developmental arrest caused by cytoplasmic inferiority of in vitro-grown (IVG) mouse oocytes?

SUMMARY ANSWER

PNT to in vivo matured cytoplasm significantly improved embryo development of IVG mouse oocytes, leading to living, fertile offspring.

WHAT IS KNOWN ALREADY

In vitro follicle culture has been considered as a fertility preservation option for cancer patients. Studies describing the culture of human follicles remain scarce, owing to low availability of tissue. Mouse models have extensively been used to study and optimize follicle culture. Although important achievements have been accomplished, including the production of healthy offspring in mice, IVG oocytes are of inferior quality when compared to in vivo-grown oocytes, likely because of cytoplasmic incompetence.

STUDY DESIGN SIZE DURATION

The study was carried out from September 2020 to February 2022. In total, 120 15-day-old B6D2 mice were used to perform secondary follicle culture and assess the quality of IVG oocytes. In vivo-grown control oocytes were obtained from 85 8- to 12-week-old B6D2 mice, following ovarian stimulation. For sperm collection, four B6D2 males between 10 and 14 weeks old were used. For embryo transfer, 14 8- to 12-week-old CD1 females served as surrogate mothers and 10 CD1 vasectomized males 10-24 weeks old were used to generate pseudo-pregnant females. Finally, for mating, four B6D2 female mice aged 8-10 weeks and two B6D2 male mice aged 10 weeks old were used to confirm the fertility of nuclear transfer (NT)-derived pups.

PARTICIPANTS/MATERIALS SETTING METHODS

Secondary follicles from 15-day-old B6D2 mice were isolated from the ovaries and cultured for 9 days, before a maturation stimulus was given. Following 16-18 h of maturation, oocytes were collected and evaluated on maturation rate, oocyte diameter, activation rate, spindle morphology, calcium-releasing ability, and mitochondrial membrane potential. For every experiment, in vivo-grown oocytes were used as a control for comparison. When cytoplasmic immaturity and poor embryo development were confirmed in IVG oocytes, PNT was performed. For this, the pronuclei from IVG oocytes, created following parthenogenetic activation and IVF, were transferred to the cytoplasm of fertilized, in vivo-grown oocytes. Genetic analysis and embryo transfer of the generated embryos were implemented to confirm the safety of the technique.

MAIN RESULTS AND THE ROLE OF CHANCE

Following 9 days of follicle culture, 703 oocytes were collected, of which 76% showed maturation to the metaphase II stage. Oocyte diameters were significantly lower in IVG oocytes, measuring 67.4 μm versus 73.1 μm in controls (P < 0.001). Spindle morphology did not differ significantly between IVG and control oocytes, but calcium-releasing ability was compromised in the IVG group. An average calcium release of 1.62 arbitrary units was observed in IVG oocytes, significantly lower than 5.74 in control oocytes (P < 0.001). Finally, mitochondrial membrane potential was inferior in IVG compared to the control group, reaching an average value of 0.95 versus 2.27 (P < 0.001). Developmental potential of IVG oocytes was assessed following parthenogenetic activation with strontium chloride (SrCl2). Only 59.4% of IVG oocytes cleaved to two cells and 36.3% reached the blastocyst stage, significantly lower than 89.5% and 88.2% in control oocytes, respectively (P < 0.001 and 0.001). Both PNT and spindle transfer (ST) were explored in pilot experiments with parthenogenetically activated oocytes, as a means to overcome poor embryo development. After the added value of NT was confirmed, we continued with the generation of biparental embryos by PNT. For this purpose, IVG and control oocytes first underwent IVF. Only 15.5% of IVG oocytes were normally fertilized, in contrast to 45.5% in controls (P < 0.001), with resulting failure of blastocyst formation in the IVG group (0 versus 86.2%, P < 0.001). When the pronuclei of IVG zygotes were transferred to the cytoplasm of control zygotes, the blastocyst rate was restored to 86.9%, a similar level as the control. Genetic analysis of PNT embryos revealed a normal chromosomal profile, to a rate of 80%. Finally, the generation of living, fertile offspring from PNT was possible following embryo transfer to surrogate mothers.

LARGE-SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

Genetic profiles of analysed embryos from PNT originate from groups that are too small to draw concrete conclusions, whilst ST, which would be the preferred NT approach, could not be used for the generation of biparental embryos owing to technical limitations. Even though promising, the use of PNT should be considered as experimental. Furthermore, results were acquired in a mouse model, so validation of the technique in human IVG oocytes needs to be performed to evaluate the clinical relevance of the technology. The genetic profiles from IVG oocytes, which would be the ultimate characterization for chromosomal abnormalities, were not analysed owing to limitations in the reliable analysis of single cells.

WIDER IMPLICATIONS OF THE FINDINGS

PNT has the ability to overcome the poor cytoplasmic quality of IVG mouse oocytes. Considering the low maturation efficiency of human IVG oocytes and potential detrimental effects following long-term in vitro culture, NT could be applied to rescue embryo development and could lead to an increased availability of good quality embryos for transfer.

STUDY FUNDING/COMPETING INTERESTS

A.C. is a holder of FWO (Fonds voor Wetenschappelijk Onderzoek) grants (1S80220N and 1S80222N). B.H. and A.V.S. have been awarded with a special BOF (Bijzonder Onderzoeksfonds), GOA (Geconcerteerde onderzoeksacties) 2018000504 (GOA030-18 BOF) funding. B.H. has been receiving unrestricted educational funding from Ferring Pharmaceuticals (Aalst, Belgium). The authors declare that they have no conflict of interest.

Analysis of Mexican young women with primary ovarian insufficiency induced by gynaecological and haematological cancer management

This was a retrospective study that included 114 women younger than 40 years with induced primary ovarian insufficiency. Patients who presented vasomotor symptoms had a higher proportion (26 [63.41%] versus 58 [79.45%], OR 2.23, 95% CI 0.95-5.23, p = .065) to initiate hormone replacement therapy. Vasomotor symptoms were present in patients with ovarian cancer (OR 0.27, 95% CI 0.09-0.8, p = .18), haematologic cancer (OR 0.11, 95% CI 0.2-0.65, p = .014), radiotherapy (OR 2.62, 95% CI 1.04-6.54, p = .039) and chemotherapy with radiotherapy (OR 2.72, 95% CI 1.01-7.35, p = .049). Having ovarian or haematological cancer, being managed with radiotherapy and/or chemotherapy, and having follicle-stimulating hormone parameters higher than 35 mUI/mL are factors that significantly increase the risk of presenting vasomotor symptoms.Impact StatementWhat is already known on this subject? In young women with cancer, induced primary ovarian insufficiency can result as an ovarian surgery or as an adverse effect of chemotherapy or radiotherapy. Regardless of aetiology, patients are going to manifest early climacteric symptoms with an increased risk for cardiovascular disease, metabolic syndrome and osteoporosis.What do the results of this study add? Patients who presented vasomotor symptoms had initially a higher proportion of hormone replacement therapy. Patients that were treated exclusively with radiotherapy or with chemotherapy and concomitant radiotherapy have a significantly increased risk to manifest vasomotor symptoms.What are the implications of these findings for clinical practice and/or future research? Having ovarian or haematological cancer, being managed with radiotherapy and/or chemotherapy and having follicle-stimulating hormone parameters higher than 35 mUI/mL are factors that significantly increase the risk of presenting vasomotor symptoms.

Fertility Preservation in Women with Endometriosis

Several mechanisms have been implicated in the pathogenesis of endometriosis-related infertility. For patients considering surgery, the risk of iatrogenic injury is among the most important factors in the context of fertility preservation, along with age and individual reproductive goals. In the case of endometrioma excision, evidence overwhelmingly demonstrates the negative impact of surgery on ovarian reserve, with significant reductions in antimullerian hormone (up to 30% in unilateral versus up to 44% in bilateral endometriomas). The surgical endometriosis patient should be thoroughly counseled regarding fertility preservation and discussion should include tissue, embryo, and oocyte cryopreservation options. For the latter, data support cryopreservation of 10-15 oocytes in women ≤35 years and over 20 for those >35 years for a realistic chance to achieve one or more live births. When performing surgical interventions for endometriosis, reproductive surgeons should employ fertility-conserving surgical methods to reduce the likelihood of postoperative iatrogenic diminished ovarian reserve.

Vitrification versus slow freezing of human ovarian tissue: a systematic review and meta-analysis of histological outcomes

A systematic review and meta-analysis of pertinent literature published from 2006 to January 2022 were conducted to study and compare vitrification and slow freezing, the two prominent methods of ovarian tissue cryopreservation. The primary outcome measures for this study were (1) proportion of intact primordial follicles, (2) proportion of intact stromal cells, (3) proportion of DNA fragmentation in primordial follicles, and (4) mean primordial follicle density. This meta-analysis of 19 studies revealed a significantly greater proportion of intact stromal cells in vitrified tissue versus slow-frozen tissue. No significant differences upon pooled analyses were observed between the two cryopreservation methods with respect to the proportion of intact primordial follicles, proportion of DNA fragmentation, or mean primordial follicle density. Due to differences seen in stromal cell viability, vitrification may be a preferred option to preserve histology of tissue. However, more work should be done to compare the two freezing techniques with less heterogeneity caused by patients, samples, and protocols.

Umbilical Cord Mesenchymal Stem Cells Ameliorate Premature Ovarian Insufficiency in Rats

Premature ovarian insufficiency (POI) or premature ovarian failure (POF) is known as a state of hypergonadotropic hypogonadism. Stem cell therapy is expected to be used in the treatment of POI. The aim of the present study was to explore the feasibility and effectiveness of umbilical cord mesenchymal stem cell (UCMSC) transplantation for the treatment of POI in a rat model of POI induced by cyclophosphamide (CTX) injection. The ovarian function was examined by evaluating the weight of the ovary and body, estrus cycle, ovarian morphology, hormonal secretion, granulosa cell apoptosis, and fertility. The results showed that the ovarian function indicators of the modeled rats were comparable to those of the control rats after UCMSC transplantation, indicating that the ovarian function of the modeled rats recovered to a satisfactory extent. Our research may provide an experimental clue for the clinical application of UCMSC transplantation in the treatment of POI. Further experiments will focus on the detailed signaling pathway study of the molecular mechanisms of injury and repairment on the treatment with UCMSCs transplantation in the rat POI models.

The Experience of Fertility Preservation in a Single Tertiary Center in Korea

OBJECTIVE

Oocyte (OC), embryo (EC), and ovarian tissue cryopreservation (OTC) are options for fertility preservation (FP) before going through gonadotoxic cancer treatment, or anticipated fertility decline in benign ovarian diseases, or for planned OC. The aim of this study is to report outcomes of FP in a single tertiary hospital in Korea.

METHODS

This is a retrospective study of OC, EC, and OTC cycles. All patients who visited or were referred to the infertility clinic at the Department of Obstetrics and Gynecology for the purpose of FP between 2010 and October 2021 were included.

RESULTS

A total of 564 controlled ovarian stimulation cycles were conducted in 416 women. Three hundred fifty-seven women underwent 494 OC cycles. Most patients were diagnosed with breast cancer (22.4%), followed by endometriomas (21.9%), and then by planned OC (20.7%). Cases of OC have increased over the years, peaking at 109 cycles in 2019 compared to one in 2010. Fifty-nine women underwent 70 EC cycles, and breast cancer (50.8%) was the most common indication. Repetitive OC and EC cycles were undergone in 92 and 9 women, respectively (mean number of repetition, 1.37 and 1.19 times in OC and EC, respectively), yielding a maximum number of 33 oocytes or 23 embryos being cryopreserved per patient. The utilization rate was 3.1% (11/357) in OC and 16.9% (10/59) in EC. Twenty-six women underwent OTC, and gynecologic cancer was the most common indication (9/26, 34.6%). One woman had the cryopreserved ovarian tissue retransplanted and successfully generated embryos.

CONCLUSION

OC, EC, and OTC are possible options for preserving fertility, and these opportunities should be provided for women at risk of fertility decline or those who are eager to protect their future fertility. This is the first report on long-term FP outcomes in a single tertiary center in Korea. We expect that there will be more cases over the years and more women returning to use their gametes or embryos for pregnancy.

Pharmacological inhibition of the PI3K/PTEN/Akt and mTOR signalling pathways limits follicle activation induced by ovarian cryopreservation and in vitro culture

BACKGROUND

Cryopreservation and transplantation of ovarian tissue (OTCTP) represent a promising fertility preservation technique for prepubertal patients or for patients requiring urgent oncological management. However, a major obstacle of this technique is follicle loss due to, among others, accelerated recruitment of primordial follicles during the transplantation process, leading to follicular reserve loss in the graft and thereby potentially reducing its lifespan. This study aimed to assess how cryopreservation itself impacts follicle activation.

RESULTS

Western blot analysis of the PI3K/PTEN/Akt and mTOR signalling pathways showed that they were activated in mature or juvenile slow-frozen murine ovaries compared to control fresh ovaries. The use of pharmacological inhibitors of follicle signalling pathways during the cryopreservation process decreased cryopreservation-induced follicle recruitment. The second aim of this study was to use in vitro organotypic culture of cryopreserved ovaries and to test pharmacological inhibitors of the PI3K/PTEN/Akt and mTOR pathways. In vitro organotypic culture-induced activation of the PI3K/PTEN/Akt pathway is counteracted by cryopreservation with rapamycin and in vitro culture in the presence of LY294002. These results were confirmed by follicle density quantifications. Indeed, follicle development is affected by in vitro organotypic culture, and PI3K/PTEN/Akt and mTOR pharmacological inhibitors preserve primordial follicle reserve.

CONCLUSIONS

Our findings support the hypothesis that inhibitors of mTOR and PI3K might be an attractive tool to delay primordial follicle activation induced by cryopreservation and culture, thus preserving the ovarian reserve while retaining follicles in a functionally integrated state.

Matrix-free 3D culture supports human follicular development from the unilaminar to the antral stage in vitro yielding morphologically normal metaphase II oocytes

STUDY QUESTION

Can group culture with stage-specific anti-Müllerian hormone (AMH) modulation support human follicular development and oocyte maturation in vitro?

SUMMARY ANSWER

In the presence of FSH, AMH supplementation at the secondary-to-early antral stage followed by AMH depletion promotes the coordinated growth and function of human follicles during group culture, thereby yielding mature oocytes.

WHAT IS KNOWN ALREADY

Stage-specific AMH modulation promotes in-vitro development of nonhuman primate follicles. The group culture method supports nonhuman primate follicle growth from the primary to antral stage, producing developmentally competent oocytes.

STUDY DESIGN, SIZE, DURATION

Ovarian tissue samples were collected from 19 patients of reproductive age (22-47 years old having menstrual cycles) who underwent oophorectomy or hysterectomy for clinical purposes. Tissue pieces were cultured in a matrix-free system for 3 weeks followed by isolation of follicles for the subsequent 6-week individual or group culture.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Pieces of ovarian cortical tissue were cultured to support primordial follicle activation and early-stage follicle growth. Secondary follicles isolated from cultured tissue were then randomly assigned to two groups for individual culture: control and AMH modulation, i.e., recombinant human AMH protein supplementation during the secondary-to-early antral stage followed by the addition of neutralizing anti-human AMH antibody. Secondary follicles were also cultured in groups with the same AMH modulation. Follicle survival, growth, steroid hormone and paracrine factor production, steroidogenic protein expression, as well as oocyte maturation and morphology were assessed.

MAIN RESULTS AND THE ROLE OF CHANCE

Follicles grew to the secondary stage during 3 weeks of ovarian tissue culture. In-vitro-developed follicles expressed AMH and levels of secreted AMH increased (P < 0.05) in the culture media over time. Secondary follicles isolated from cultured ovarian tissue survived and grew to the antral stage during 6 weeks of individual follicle culture. In-vitro-developed antral follicles produced granulosa and theca cell-derived steroid hormones and paracrine factors, which were detectable in the culture media. Germinal vesicle oocytes obtained from cultured follicles exhibited a perinucleolar chromatin rim configuration. AMH modulation did not alter follicle survival or oocyte maturation relative to those of the control follicles. However, follicle diameters, as well as steroid hormone and paracrine factor production, increased (P < 0.05) in the AMH-modulation group compared with the control group. Secondary follicles isolated from cultured ovarian tissue formed aggregates and grew to the antral stage during 6 weeks of group culture. In-vitro-developed antral follicles expressed steroidogenic enzymes and secreted steroid hormones were detectable in the culture media. Oocytes obtained from cultured follicle aggregates with AMH-modulation progressed to the metaphase II stage after IVM, containing a normal-sized first polar body and meiotic spindle. Oocytes exhibited a typical ultrastructure.

LIMITATIONS, REASONS FOR CAUTION

Follicles were obtained from fresh ovarian tissue of adult patients. Oocyte maturation rates were relatively low and oocytes were assessed by morphological evaluation. Owing to the lack of a control group, the beneficial effects of AMH modulation remained undetermined for the group culture in this study.

WIDER IMPLICATIONS OF THE FINDINGS

Stage-specific AMH modulation supports human follicular development in the matrix-free group culture, which is consistent with previously reported AMH actions on growing follicles in nonhuman primates. Oocytes generated by in-vitro-developed follicles achieve meiotic maturation with a typical morphology and ultrastructure, which supports in-vitro follicle maturation as a potential approach for fertility preservation in women.

STUDY FUNDING/COMPETING INTEREST(S)

NICHD R01HD082208 and NIH Office of the Director P51OD011092. The authors have no competing interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Heterotopic autotransplantation of equine ovarian tissue using intramuscular versus subvulvar grafting sites: Preliminary results

Ovarian tissue transplantation (OTT) is a technique well established and successfully applied in humans using mainly orthotopic or heterotopic transplantation sites. In livestock, OTT is still in its infancy and, therefore, different aspects of the technique, including the efficiency of different heterotopic OTT sites as well as the potential effect of age (i.e., young vs. old mares) in the ovarian graft quality, need to be investigated. The present study investigated the efficacy of the intramuscular (IM) or the novel subvulvar mucosa (SV) heterotopic autotransplantation sites to maintain the survivability of the grafts for 3 and 7 days post-OTT. Ovarian biopsy fragments were obtained in vivo and distributed to the following treatments: Fresh control group (ovarian fragments immediately fixed), SV-3, IM-3, SV-7, and IM-7. During and after graft harvesting, the macroscopic characteristics of the grafts (i.e., adherence, morphology, and bleeding) were scored, and the percentages of morphologically normal and developing preantral follicles as well as the follicular and stromal cell densities of the grafts were evaluated. The results were that similar (P > 0.05) macroscopic scores were observed between both transplantation sites 7 days post-OTT, with positive correlations (P < 0.01) found among adherence, morphology, and bleeding of the grafts. A lower (P < 0.05) percentage of morphologically normal follicles was found 7 days post-OTT in the SV site (82%) compared with the Fresh control group (99%) and IM site (95%); however, the percentages of developing follicles were similar (P > 0.05) between both transplantation sites 7 days post-OTT (30-43%). Although similar (P > 0.05) follicular densities were found in both transplantation sites in young and old mares at 3 and 7 days post-OTT, large individual variation in the follicular depletion rate was observed regardless of transplantation site. The Fresh control group and SV-7 treatments had higher (P < 0.05) stromal cell densities in young and old mares compared with both IM-7 treatments. When comparing transplant sites between young and old mares, the follicular density in old mares and the stromal cell density in young mares were greater (P < 0.05) in the SV than in the IM site. In conclusion, even though the transplantation sites differentially affected some end points, overall comparable findings of the OTT technique using both heterotopic autotransplantation sites (i.e., IM and SV) for equine ovarian tissue were observed.

Purging human ovarian cortex of contaminating leukaemic cells by targeting the mitotic catastrophe signalling pathway

PURPOSE

Is it possible to eliminate metastasised chronic myeloid leukaemia (CML) and acute myeloid leukaemia (AML) cells from ovarian cortex fragments by inhibition of Aurora B/C kinases (AURKB/C) without compromising ovarian tissue or follicles?

METHODS

Human ovarian cortex tissue with experimentally induced tumour foci of CML, AML and primary cells of AML patients were exposed to a 24h treatment with 1 μM GSK1070916, an AURKB/C inhibitor, to eliminate malignant cells by invoking mitotic catastrophe. After treatment, the inhibitor was removed, followed by an additional culture period of 6 days to allow any remaining tumour cells to form new foci. Ovarian tissue integrity after treatment was analysed by four different assays. Appropriate controls were included in all experiments.

RESULTS

Foci of metastasised CML and AML cells in ovarian cortex tissue were severely affected by a 24h ex vivo treatment with an AURKB/C inhibitor, leading to the formation of multi-nuclear syncytia and large-scale apoptosis. Ovarian tissue morphology and viability was not compromised by the treatment, as no significant difference was observed regarding the percentage of morphologically normal follicles, follicular viability, glucose uptake or in vitro growth of small follicles between ovarian cortex treated with 1 μM GSK1070916 and the control.

CONCLUSION

Purging of CML/AML metastases in ovarian cortex is possible by targeting the Mitotic Catastrophe Signalling Pathway using GSK1070916 without affecting the ovarian tissue. This provides a therapeutic strategy to prevent reintroduction of leukaemia and enhances safety of autotransplantation in leukaemia patients currently considered at high risk for ovarian involvement.

Hormonal Stimulation of Human Ovarian Xenografts in Mice: Studying Folliculogenesis, Activation, and Oocyte Maturation

Ovarian tissue cryopreservation and banking provides a fertility preservation option for patients who cannot undergo oocyte retrieval; it is quickly becoming a critical component of assisted reproductive technology programs across the world. While the transplantation of cryopreserved ovarian tissue has resulted in over 130 live births, the field has ample room for technological improvements. Specifically, the functional timeline of grafted tissue and each patient's probability of achieving pregnancy is largely unpredictable due to patient-to-patient variability in ovarian reserve, lack of a reliable method for quantifying follicle numbers within tissue fragments, potential risk of reintroduction of cancer cells harbored in ovarian tissues, and an inability to control follicle activation rates. This review focuses on one of the most common physiological techniques used to study human ovarian tissue transplantation, xenotransplantation of human ovarian tissue to mice and endeavors to inform future studies by discussing the elements of the xenotransplantation model, challenges unique to the use of human ovarian tissue, and novel tissue engineering techniques currently under investigation.

Clinical analysis of human umbilical cord mesenchymal stem cell allotransplantation in patients with premature ovarian insufficiency

Objective

Premature ovarian insufficiency (POI) is a refractory disease that seriously affects female fertility. Growing body of evidence has indicated mesenchymal stem cells (MSCs) as promising resources in regenerative medicine. In this study, we treated POI patients with umbilical cord‐derived MSCs (UCMSCs) and then investigated the restoration of ovarian function and clinical outcomes through follow‐ups.

Materials and methods

Sixty‐one patients diagnosed with POI participated in this study. UCMSCs were isolated and cultured according to GMP standards, and then transplanted to the patients’ ovary by orthotopic injection under the guidance of vaginal ultrasound. We monitored side effects, vital signs and changes in clinical and collected haematological and imaging parameters during the follow‐ups.

Results

All patients showed normal clinical behaviour without serious side effects or complications relevant to the treatment. Transplantation of UCMSCs rescued the ovarian function of POI patients, as indicated by increased follicular development and improved egg collection. POI patients who experienced shorter amenorrhoea durations (<1 year) seemed to obtain mature follicles more easily after stem cell therapy, and patients with better ovarian conditions (pre‐operative antral follicles) were more likely to derive the better outcomes by UCMSC injection. Four successful clinical deliveries were obtained from POI patients after UCMSC transplantation, and all of these babies are developed normally.

Conclusions

The clinical trial result sugggests a possible therapy for POI by UCMSC transplantation.

Human Ovarian Cortex biobanking: A Fascinating Resource for Fertility Preservation in Cancer

Novel anti-cancer treatments have improved the survival rates of female young patients, reopening pregnancy issues for female cancer survivors affected by the tumor treatment-related infertility. This condition occurs in approximately one third of women of fertile age and is mainly dependent on gonadotoxic protocols, including radiation treatments. Besides routine procedures such as the hormonal induction of follicular growth and subsequent cryopreservation of oocytes or embryos, the ovarian protection by gonadotropin-releasing hormone (GnRH) agonists during chemotherapy as well as even gonadal shielding during radiotherapy, other innovative techniques are available today and need to be optimized to support their introduction into the clinical practice. These novel methods are hormone stimulation-free and include the ovarian cortex cryopreservation before anti-cancer treatments and its subsequent autologous reimplantation and a regenerative medicine approach using oocytes derived in vitro from ovarian stem cells (OSCs). For both procedures, the major benefit is related to the prompt recruitment and processing of the ovarian cortex fragments before gonadotoxic treatments. However, while the functional competence of oocytes within the cryopreserved cortex is not assessable, the in vitro maturation of OSCs to oocytes, allows to select the most competent eggs to be cryopreserved for fertility restoration.

Reproductive outcomes following a stem cell transplant for a haematological malignancy in female cancer survivors: a systematic review and meta-analysis

PURPOSE

The use of high-dose chemotherapy and radiotherapy combined with haematopoietic stem cell transplantation (HSCT) may negatively affect a woman's reproductive potential. Reproductive outcomes such as infertility are a major concern for women who undergo treatment for a haematological cancer diagnosis.

OBJECTIVE

This systematic review and meta-analysis explores reproductive outcomes following a haematological cancer requiring HSCT.

METHODS

Electronic databases were searched to identify studies that reported on reproductive outcomes after treatment for a haematological cancer diagnosis. Studies were included that reported on pregnancy and reproductive outcomes following HSCT for a haematological malignancy.

RESULTS

The meta-analysis included 14 studies, collectively involving 744 female patients. The subgroup analysis showed an overall pooled estimated pregnancy rate, for autologous or allogeneic HSCT recipients, of 22.7% (n = 438). There were 25% (n = 240) of women who became pregnant after autologous HSCT compared with 22% (n = 198) who subsequently became pregnant following allogeneic HSCT.

CONCLUSIONS

This meta-analysis reflects low pregnancy rates for cancer survivors desiring a family. However, live births are improving over time with new technology and novel therapies. Hence, female cancer patients should be offered timely discussions, counselling and education around fertility preservation options prior to starting treatment with gonadotoxic therapy.

A case report and follow-up of the first live birth after heterotopic transplantation of cryopreserved ovarian tissue in Eastern Europe

Background

Ovarian insufficiency is a major concern for long-term cancer survivors. Although semen freezing is well established to preserve male fertility, the possibilities to secure post-cancer female fertility are mostly limited to oocyte or embryo freezing. These methods require time-consuming ovarian stimulation with or without in vitro fertilization (IVF) that evidently delays cancer therapy. Ovarian tissue cryopreservation and subsequent thawed tissue autotransplantation are considered the most promising alternative strategy for restoring the fertility of oncology patients, which has not yet received the full clinical acceptance. Therefore, all successful cases are needed to prove its reliability and safety.

Case presentation

Here we report a single case in Estonia, where a 28-year-old woman with malignant breast neoplasm had ovarian cortex cryopreserved before commencing gonadotoxic chemo- and radiotherapy. Two years after cancer therapy, the patient underwent heterotopic ovarian tissue transplantation into the lateral pelvic wall. The folliculogenesis was stimulated in the transplanted tissue by exogenous follicle-stimulating hormone and oocytes were collected under ultrasound guidance for IVF and embryo transfer. The healthy boy was born after full-term gestation in 2014, first in Eastern Europe.

Conclusion

Despite many countries have reported the first implementation of the ovarian tissue freezing and transplantation protocols, the data is still limited on the effectiveness of heterotopic ovarian transplant techniques. Thus, all case reports of heterotopic ovarian tissue transplantation and long-term follow-ups to describe the children’s health are valuable source of clinical experience.

Radiations and female fertility

Hundreds of thousands of young women are diagnosed with cancer each year, and due to recent advances in screening programs, diagnostic methods and treatment options, survival rates have significantly improved. Radiation therapy plays an important role in cancer treatment and in some cases it constitutes the first therapy proposed to the patient. However, ionizing radiations have a gonadotoxic action with long-term effects that include ovarian insufficiency, pubertal arrest and subsequent infertility. Cranial irradiation may lead to disruption of the hypothalamic-pituitary-gonadal axis, with consequent dysregulation of the normal hormonal secretion. The uterus might be damaged by radiotherapy, as well. In fact, exposure to radiation during childhood leads to altered uterine vascularization, decreased uterine volume and elasticity, myometrial fibrosis and necrosis, endometrial atrophy and insufficiency. As radiations have a relevant impact on reproductive potential, fertility preservation procedures should be carried out before and/or during anticancer treatments. Fertility preservation strategies have been employed for some years now and have recently been diversified thanks to advances in reproductive biology. Aim of this paper is to give an overview of the various effects of radiotherapy on female reproductive function and to describe the current fertility preservation options.

Ovarian tissue cryopreservation and transplantation in patients with cancer

Chemotherapy and radiotherapy improved survival rates of patients with cancer. However, they can cause ovarian failure and infertility in women of reproductive age. Infertility following cancer treatment is considered a major quality of life issue. Ovarian tissue cryopreservation and transplantation is an important option for fertility preservation in adult patients with cancer who need immediate chemotherapy or do not want to undergo ovarian stimulation. Ovarian tissue freezing is the only option for preserving the fertility of prepubertal patients with cancer. In a recent review, it was reported that frozen-thawed ovarian transplantation has lead to about 90 live births and the conception rate was about 30%. Endocrine function recovery was observed in 92.9% between 3.5 and 6.5 months after transplantation. Based on our review, ovarian tissue cryopreservation and transplantation may be carefully considered before cancer treatment in order to preserve fertility and endocrine function in young cancer survivors.

Comparison of the enzymatic efficiency of Liberase TM and tumor dissociation enzyme: effect on the viability of cells digested from fresh and cryopreserved human ovarian cortex

BACKGROUND

The aim of this study was to examine the effectiveness of Tumor Dissociation Enzyme (TDE) on the viability of follicles after digestion of fresh and cryopreserved ovarian cortex fragments (OCFs).

METHODS

Fresh and thawed OCF from 14 patients (29 ± 6 years), sized 20 to 210 mm³ were randomly distributed into four treatment groups and digested with 16% TDE or 0.05 mg/ml Liberase TM: Group 1, frozen OCF digested with TDE; Group 2, frozen OCF digested with LiberaseTM; Group 3, fresh OCF digested with TDE; and Group 4, fresh OCF digested with Liberase TM. Evaluation of follicle viability was performed under light microscope after staining with Neutral red. For visualization of viable and dead cells under a confocal laser scanning microscope, the follicles were stained with Calcein AM and ethidium homodimer-1.

RESULTS

The results showed that the number of retrieved follicles was significantly higher (990 vs 487; P < 0.01) in the TDE-treatment group compared to the Liberase TM-group. The presence of intense neutral red stained follicles was significantly higher in Group 1 and Group 3 compared to Group 2 and Group 4 (70.3% ± +/- 6.22 vs 53,1% ± 2.03 and 94.2% ± 6.6 vs 79.1% ± 2.1; P < 0.01). The percentage of Calcein AM stained follicles of class V1 was significantly higher in Group 1 and Group 3 compared to Group 2 and Group 4 (95.97% ± 7.8 vs 87.87% ± 2.4; 97.1% ± 6.8 vs 91.3% ± 2.3; P < 0.01).

CONCLUSION

The enzymatic digestion of ovarian cortex with TDE provides recovery of a higher number of healthy preantral follicles in contrast to earlier described Liberase TM procedure.

Outcome of immature oocytes collection of 119 cancer patients during ovarian tissue harvesting for fertility preservation

PURPOSE

Few clinical options for fertility preservation are available to females with cancer, and data about clinical outcomes is limited. Potential supplementary approaches to fertility preservation include retrieval of immature oocytes followed by in vitro maturation (IVM) and storage. The aim of this study was to evaluate post-thawing outcomes of immature oocytes collected both by transvaginal aspiration and from excised ovarian tissue.

METHODS

We conducted a retrospective cohort study of patients treated in a single tertiary center. We reviewed the records of 119 cancer patients who underwent ovarian tissue cryopreservation and immature oocyte harvesting for fertility preservation. All embryos and oocytes that were frozen and thawed were included in the study. Post-thawing outcomes were evaluated.

RESULTS

Thirty-five stored embryos from eight patients were thawed. Twenty-nine embryos survived (82% survival rate) and were transferred. Six oocytes were thawed, two oocytes survived, and no oocytes were fertilized. Only one PCOS patient became pregnant, resulting in the normal delivery of a healthy baby.

CONCLUSIONS

Although a relatively high number of mature oocytes and embryos can be stored with the combined procedure, the limited rate of pregnancies represents a poor reproductive outcome. Therefore, this approach should be reserved for special groups with limited options.

Female fertility preservation in the pediatric and adolescent cancer patient population

The 5-year survival rate for childhood cancer is over 80%, thereby increasing the number of young women facing infertility in the future because of the gonadotoxic effects of chemotherapy and radiation. The gonadotoxic effects of childhood cancer treatment vary by the radiation regimen and the chemotherapeutic drugs utilized. Although the American Society of Clinical Oncology guidelines recommend fertility preservation for all patients, there are several barriers and ethical considerations to fertility preservation in the pediatric and adolescent female population. Additionally, the fertility preservation methods for pre- and postpubertal females differ, with only experimental methods available for prepubertal females. We will review the risk of chemotherapy and radiation on female fertility, the approach to fertility preservation in the pediatric and adolescent female population, methods of fertility preservation for both pre- and postpubertal females, barriers to fertility preservation, cost, and psychological and ethical considerations.

Expectations and limitations of ovarian tissue transplantation

Constant progress in the diagnosis and treatment of cancer disease has increased the number and prognosis of cancer survivors. However, the toxic effects of chemotherapy and radiotherapy on ovarian function have resulted in premature ovarian failure. Patients are, therefore, still expecting methods to be developed to preserve their fertility successfully. Several potential options are available to preserve fertility in patients who face premature ovarian failure, including immature or mature oocyte and embryo cryopreservation. However, for children or prepubertal women needing immediate chemotherapy, cryopreservation of ovarian tissue is the only alternative. The ultimate aim of this strategy is to implant ovarian tissue into the pelvic cavity (orthotopic site) or in a heterotopic site once oncological treatment is completed and the patient is disease free. Transplantation of ovarian tissue with sufficiently large numbers of follicles could potentially restore endocrine function and allow multiple cycles for conception. However, the success of ovarian tissue transplantation still has multiple challenges, such as the low number of follicles in the graft that may affect their longevity as well as the survival of the tissue during ex vivo processing and subsequent transplantation. Therefore, this review aims to summarize the achievements of ovary grafting and the potential techniques that have been developed to improve ovarian graft survival.

Fertility Preservation in Cancer Patients: In Vivo and In Vitro Options

Oocyte, embryo and ovarian tissue cryopreservation are being increasingly proposed for fertility preservation among cancer patients undergoing therapy to enable them to have babies after the cancer is cured. Embryo cryopreservation is not appropriate for single girls without any sperm partner and also because oocyte retrieval is an extended procedure, it is impossible in cases requiring immediate cancer cure. Thus ovarian tissue cryopreservation has been suggested for fertility preservation especial in cancer patients. The main goal of ovarian cryopreservation is re-implanting the tissue into the body to restore fertility and the hormonal cycle. Different cryopreservation protocols have been examined and established for vitrification of biological samples. We have used Cryopin to plunge ovarian tissue into the liquid nitrogen and promising results have been observed. Ovarian tissue re-implantation after cancer cure has one problem- the possibility of recurrence of malignancy in the reimplanted tissue is high. Xenografting-implantation of the preserved tissue in another species- also has its drawbacks such as molecular signaling from the recipient. In vitro follicle culturing is a safer method to obtain mature oocytes for fertilization and the various studies that have been carried out in this area are reviewed in this paper.

Recent advances in the field of ovarian tissue cryopreservation and opportunities for research

PURPOSE

The purpose of this study was to summarize the latest advances and successes in the field of ovarian tissue cryopreservation while identifying gaps in current knowledge that suggest opportunities for future research.

METHODS

A systematic review was performed according to PRISMA guidelines for all relevant full-text articles in PubMed published in English that reviewed or studied historical or current advancements in ovarian tissue cryopreservation and auto-transplantation techniques.

RESULTS

Ovarian tissue auto-transplantation in post-pubertal women is capable of restoring fertility with over 80 live births currently reported with a corresponding pregnancy rate of 23 to 37%. The recently reported successes of live births from transplants, both in orthotopic and heterotopic locations, as well as the emerging methods of in vitro maturation (IVM), in vitro culture of primordial follicles, and possibility of in vitro activation (IVA) suggest new fertility options for many women and girls. Vitrification, as an ovarian tissue cryopreservation technique, has also demonstrated successful live births and may be a more cost-effective method to freezing with less tissue injury. Further, transplantation via the artificial ovary with an extracellular tissue matrix (ECTM) scaffolding as well as the effects of sphingosine-1-phosphate (SIP) and fibrin modified with heparin-binding peptide (HBP), heparin, and a vascular endothelial growth factor (VEGF) have demonstrated important advancements in fertility preservation. As a fertility preservation method, ovarian tissue cryopreservation and auto-transplantation are currently considered experimental, but future research may pave the way for these modalities to become a standard of care for women facing the prospect of sterility from ovarian damage.

Microfluidic Encapsulation of Ovarian Follicles for 3D Culture

The ovarian follicle that contains one single oocyte is the fundamental functional tissue unit of mammalian ovary. Therefore, isolation and in vitro culture of ovarian follicles to obtain fertilizable oocytes are regarded as a promising strategy for women to combat infertility. In this communication, we performed a brief survey of studies on microfluidic encapsulation of ovarian follicles in core-shell hydrogel microcapsules for biomimetic 3D culture. These studies highlighted that recapitulation of the mechanical heterogeneity of the extracellular matrix in ovary is crucial for in vitro culture to develop early pre-antral follicles to the antral stage, and for the release of cumulus-oocyte complex (COC) from antral follicles in vitro. The hydrogel encapsulation-based biomimetic culture system and the microfluidic technology may be invaluable to facilitate follicle culture as a viable option for restoring women's fertility in the clinic.

Operative techniques and complications of extraction and transplantation of ovarian tissue: the Erlangen experience

PURPOSE

Extracting ovarian tissue before oncologic therapy and transplanting it afterwards are increasingly being used to preserve fertility in women. This study describes standardized and safe operative procedures, with few complications, and reports the resulting ovarian function and pregnancy rates.

METHODS

The standardized operative techniques for removing and transplanting ovarian tissue used at the Erlangen center are: for tissue removal, one-third to half of the tissue from one ovary is excised with scissors, without tissue coagulation; for subsequent transplantation, pieces of ovarian tissue are placed in a retroperitoneal pocket without closure of the pocket.

RESULTS

Between January 2007 and December 2015, ovarian tissue was extracted in 399 women and transplanted following cancer therapy in 38. No surgical complications were observed within 28 days. To date, there have been ten pregnancies and nine live births after transplantation in seven different women; 26 of the 38 women developed hormonal activity, confirmed by a menstrual cycle or raised serum estradiol levels.

CONCLUSIONS

The techniques for laparoscopic removal and transplantation of ovarian tissue described here provide a standardized method with a very low risk of complications. The pregnancy rate after ovarian tissue transplantation, currently 15-30%, can be expected to rise further in the near future.

In Vitro Activation of Follicles and Fresh Tissue Auto-transplantation in Primary Ovarian Insufficiency Patients

CONTEXT

Recently, two patients with primary ovarian insufficiency (POI) delivered healthy babies after in vitro activation (IVA) treatment followed by auto-transplantation of frozen-thawed ovarian tissues.

OBJECTIVE

This study sought to report the first case of live birth after IVA treatment following fresh ovarian tissue grafting in patients with POI, together with monitoring of follicle development and serum hormonal changes.

DESIGN

This was a prospective observational cohort study.

SETTING

We performed IVA treatment in 14 patients with POI with mean age of 29 years, mean duration since last menses of 3.8 years, and average basal FSH level of 94.5 mIU/mL.

INTERVENTIONS

Prior to IVA treatment, all patients received routine hormonal treatments with no follicle development. We removed one ovary from patients with POI and treated them with Akt stimulators. We improved upon early procedures by grafting back fresh tissues using a simplified protocol.

MAIN OUTCOME MEASURES

In six of the 14 patients (43%), a total of 15 follicle development waves were detected, and four patients had successful oocyte retrieval to yield six oocytes. For two patients showing no spontaneous follicle growth, human menopausal gonadotropin treatment induced follicle growth at 6-8 months after grafting. After vitro fertilization of oocyte retrieved, four early embryos were derived. Following embryo transfer, one patient became pregnant and delivered a healthy baby boy, with three other embryos under cryopreservation.

CONCLUSION

IVA technology can effectively activate residual follicles in some patients with POI and allow them to conceive their own genetic offspring. IVA may also be useful for treating patients with ovarian dysfunction including aging women and cancer survivors.

Toward precision medicine for preserving fertility in cancer patients: existing and emerging fertility preservation options for women

As the number of young cancer survivors increases, quality of life after cancer treatment is becoming an ever more important consideration. According to a report from the American Cancer Society, approximately 810,170 women were diagnosed with cancer in 2015 in the United States. Among female cancer survivors, 1 in 250 are of reproductive age. Anticancer therapies can result in infertility or sterility and can have long-term negative effects on bone health, cardiovascular health as a result of reproductive endocrine function. Fertility preservation has been identified by many young patients diagnosed with cancer as second only to survival in terms of importance. The development of fertility preservation technologies aims to help patients diagnosed with cancer to preserve or protect their fertility prior to exposure to chemo- or radiation therapy, thus improving their chances of having a family and enhancing their quality of life as a cancer survivor. Currently, sperm, egg, and embryo banking are standard of care for preserving fertility for reproductive-age cancer patients; ovarian tissue cryopreservation is still considered experimental. Adoption and surrogate may also need to be considered. All patients should receive information about the fertility risks associated with their cancer treatment and the fertility preservation options available in a timely manner, whether or not they decide to ultimately pursue fertility preservation. Because of the ever expanding number of options for treating cancer and preserving fertility, there is now an opportunity to take a precision medicine approach to informing patients about the fertility risks associated with their cancer treatment and the fertility preservation options that are available to them.

New advances in ovarian autotransplantation to restore fertility in cancer patients

Human ovary autotransplantation is a promising option for fertility preservation of young women and girls undergoing gonadotoxic treatments for cancer or some autoimmune diseases. Although experimental, it resulted in at least 42 healthy babies worldwide. According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a systematic literature review was performed for all relevant full-text articles published in English from 1 January 2000 to 01 October 2015 in PubMed to explore the latest clinical and research advances of human ovary autotransplantation. Human ovary autotransplantation involves ovarian tissue extraction, freezing/thawing, and transplantation back into the same patient. Three major forms of human ovary autotransplantation exist including (a) transplantation of cortical ovarian tissue, (b) transplantation of whole ovary, and (c) transplantation of ovarian follicles (artificial ovary). According to the recent guidelines, human ovary autotransplantation is still considered experimental; however, it has unique advantages in comparison to other options of female fertility preservation. Human ovary autotransplantation (i) does not need prior ovarian stimulation, (ii) allows immediate initiation of cancer therapy, (iii) can restore both endocrine and reproductive ovarian functions, and (iv) may be the only fertility preservation option suitable for prepubertal girls or for young women with estrogen-sensitive malignancies. As any other fertility preservation option, human ovary autotransplantation has both advantages and disadvantages and may not be feasible for all cases. The major challenges facing this option are how to avoid the risk of reintroducing malignant cells and how to prolong the lifespan of ovarian transplant as well as how to improve artificial ovary results.

Fertility Risk Assessment and Preservation in Male and Female Prepubertal and Adolescent Cancer Patients

Cancer represents the second cause of death in prepubertal children and adolescents, although it is currently associated with an overall survival rate of 80%–85%. The annual incidence rate is 186.6 per 1 million children and adolescents aged up to 19 years. Both disease and treatment options are associated with life-altering, long-term effects that require monitoring. Infertility is a common issue, and as such, fertility preservation represents an essential part in the management of young patients with cancer who are at risk of premature gonadal failure. This review deals with the up-to-date available data on fertility risk assessment and preservation strategies that should be addressed prior to antineoplastic therapy in this vulnerable subgroup of cancer patients.

What threshold values of antral follicle count and serum AMH levels should be considered for oocyte cryopreservation after in vitro maturation?

STUDY QUESTION

What threshold values of ultrasonographic antral follicle count (AFC) and serum anti-Müllerian hormone (AMH) levels should be considered for ensuring the cryopreservation of sufficient number of in vitro matured (IVM) oocytes, in cancer patients seeking fertility preservation (FP)?

SUMMARY ANSWER

AFC and serum AMH values >20 follicles and 3.7 ng/ml, respectively, are required for obtaining at least 10 IVM oocytes for cryopreservation.

WHAT IS KNOWN ALREADY

IVM of cumulus oocyte complexes (COCs) followed by oocyte cryopreservation has emerged recently as an option for urgent FP. Recent data have reported that, in healthy patients, 8-20 cryopreserved oocytes after ovarian stimulation would maximize the chance of obtaining a live birth. Although both AFC and AMH have been reported as predictive factors of IVM success in infertile patients with polycystic ovary syndrome (PCOS), there is a dramatic lack of data regarding the values of these parameters in oncological patients as candidates for FP.

STUDY DESIGN, SIZE, DURATION

From January 2009 to April 2015, we prospectively studied 340 cancer patients, aged 18-41 years, as candidates for oocyte cryopreservation following IVM.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All patients had AFC and AMH measurements, 48-72 h before oocyte retrieval, regardless of the phase of the cycle. COCs were recovered under ultrasound guidance 36 h after hCG priming. Logistic regression allowed the determination of threshold values of AFC and AMH, for obtaining at least 8, 10 or 15 matures oocytes frozen after the IVM procedure. Similar analyses were performed for a final number of mature oocytes ≤2.

MAIN RESULTS AND THE ROLE OF CHANCE

Among the 340 cancer patients included, 300 were diagnosed with breast cancers, 14 had hematological malignancies and 26 underwent the procedure for others indications. Overall, the mean age of the population was 31.8 ± 4.5 years. Mean AFC and serum AMH levels were 21.7 ± 13.3 follicles and 4.4 ± 3.8 ng/ml, respectively. IVM was performed in equal proportions during the follicular or luteal phase of the cycle (49 and 51%, respectively). Statistical analysis showed that AFC and AMH values above 28 follicles and 3.9 ng/ml, 20 follicles and 3.7 ng/ml and 19 follicles and 3.5 ng/ml are required, respectively, for obtaining at least 15, 10 or 8 frozen IVM oocytes with a sensitivity ranging from 0.82 to 0.90. On the contrary, ≤2 IVM oocytes were cryopreserved when AFC and AMH were <19 follicles and 3.0 ng/ml, respectively.

LIMITATIONS, REASONS FOR CAUTION

Although the potential of cryopreserved IVM oocytes from cancer patients remains unknown, data obtained from infertile PCOS women have shown a dramatically reduced competence of these oocytes when compared with that of oocytes recovered after ovarian stimulation. As a consequence, the optimal number of IVM oocytes frozen in candidates for FP is currently unpredictable.

WIDER IMPLICATIONS OF THE FINDINGS

Cryopreservation of oocytes after IVM should be considered in the FP strategy when ovarian stimulation is unfeasible, in particular when markers of the follicular ovarian status are at a relatively high range. Further investigation is needed to objectively assess the real potential of these IVM oocytes after cryopreservation. Therefore, even when a good COCs yield is expected, we should systematically encourage IVM in combination with ovarian tissue cryopreservation.

STUDY FUNDING/COMPETING INTERESTS

No external funding was obtained for the present study. The authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

Female fertility preservation strategies: cryopreservation and ovarian tissue in vitro culture, current state of the art and future perspectives

In the present review, the main strategies of female fertility preservation are covered. Procedures of fertility preservation are necessary for women who suffer from diseases whose treatment requires the use of aggressive therapies, such as chemotherapy and radiotherapy. These kinds of therapy negatively influence the health of gametes and their progenitors. The most commonly used method of female fertility preservation is ovarian tissue cryopreservation, followed by the retransplantation of thawed tissue. Another approach to female fertility preservation that has been actively developed lately is the ovarian tissue in vitro culture. The principal methods, advantages and drawbacks of these two strategies are discussed in this article.

Human single follicle growth in vitro from cryopreserved ovarian tissue after slow freezing or vitrification

STUDY QUESTION

What is the effect of human ovarian tissue cryopreservation on single follicular development in vitro?

SUMMARY ANSWER

Vitrification had a greater negative effect on growth and gene expression of human ovarian follicles when compared with fresh follicles.

WHAT IS KNOWN ALREADY

For human ovarian cortex cryopreservation, the conventional option is slow freezing while more recently vitrification has been demonstrated to maintain good quality and function of ovarian tissues.

STUDY DESIGN, SIZE, DURATION

Ovarian tissues were collected from 11 patients. For every patient, the ovarian cortex was divided into three samples: Fresh, slow-rate freezing (Slow) and vitrification (Vit). Tissue histology was performed and follicles were isolated for single-cell mRNA analysis and in vitro culture (IVC) in 1% alginate for 8 days.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Follicle morphology was assessed with hematoxylin-eosin analysis. Follicles were individually embedded in alginate (1% w/v) and cultured in vitro for 8 days. Follicle survival and growth were assessed by microscopy. Follicle viability was observed after Calcein-AM and ethidium homodimer-I (Ca-AM/EthD-I) staining. Expression of genes, including GDF9 (growth differentiation factor 9), BMP15 (bone morphogenetic protein 15) and ZP3 (zona pellucida glycoprotein 3) in oocytes and AMH (anti-Mullerian hormone), FSHR (FSH receptor), CYP11A (cholesterol side-chain cleavage cytochrome P450) and STAR (steroidogenic acute regulatory protein) in GCs, was evaluated by single-cell mRNA analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 129 follicles were separated from ovarian cortex (Fresh n = 44; Slow n = 40; Vit n = 45). The percentage of damaged oocytes and granulosa cells was significantly higher in both the Slow and Vit groups, as compared with Fresh control (P< 0.05). The growth of follicles in vitro was significantly delayed in the Vit group compared with the Fresh group (P< 0.05). Both slow freezing (P< 0.05) and vitrification (P< 0.05) down-regulated the mRNA levels of ZP3 and CYP11A compared with Fresh group, while there was no significant difference between the Slow and Vit groups (P> 0.05). Vitrification also down-regulates AMH mRNA levels compared with Fresh group (P< 0.05).

LIMITATIONS, REASONS FOR CAUTION

Only short-term IVC studies (8 days) are reported. Further study should be performed to examine and improve follicular development in a long-term culture system after cryopreservation.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first comparison of gene expression and growth of single human ovarian follicles in vitro after either slow freezing or vitrification. With the decreased gene expression and growth during IVC, damage by cryopreservation still exists and needs to be minimized during the long-term IVC of follicles in the future for eventual clinical application.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the National Natural Science Foundation of China (31230047, 81571386, 81471508, 31429004 and 81501247), National Natural Science Foundation of Beijing (7142166) and Mega-projects of Science Research for the 12th five-year plan (2012ba132b05). There are no conflicts of interest to declare.

Ovarian tissue freezing: current status

PURPOSE OF REVIEW

This article aims to carefully evaluate a number of critical points related to ovarian tissue freezing and presents factual data in terms of live birth rates and risks.

RECENT FINDINGS

Reimplantation of frozen-thawed ovarian tissue remains an experimental procedure according to the American Society for Reproductive Medicine, despite almost 40 live births reported in the literature. Recent literature on the topic has focused on the risk of reimplanting malignant cells, so the present review assesses the risks according to disease.

SUMMARY

This manuscript emphasizes the crucial importance of not only preserving fertility in young women but also clearly explaining to patients the different available options and their respective success rates. Some previously published reviews have reported inaccurate reimplantation success rates. In this review, we report the true picture, with a live birth rate of 25%. Ovarian tissue freezing may be combined with pickup of immature oocytes (at the time of ovarian biopsy and tissue removal) or mature oocytes (if chemotherapy can be delayed).

Assisted reproductive techniques after fertility-sparing treatments in gynaecological cancers

BACKGROUND

The trend toward late childbearing has made fertility preservation a major issue for women who face gynecological cancer. New techniques in assisted reproductive medicine enable conception after primary treatment of these cancers. Here, we aimed to review the efficacy and safety of assisted reproductive techniques (ART) after fertility-preserving treatment of gynaecological cancers.

METHODS

We conducted a systematic literature review of both prospective and retrospective studies in the PubMed, EMBASE, CENTRAL and SciSearch databases. In the retrieved studies, we evaluated live births, clinical pregnancies, overall survival and disease-free survival.

RESULTS

We identified many prospective and retrospective studies on this topic, but no relevant randomized clinical trials. Fertility-sparing treatments with safe oncological outcomes are feasible in endometrial, cervical and ovarian cancer cases. After cancer treatment, ART seem safe and show variable obstetrical outcomes.

CONCLUSIONS

After fertility-preserving treatment for gynaecological cancers, ART can enable pregnancy to be achieved with apparent oncological safety. The success of such procedures should directly impact clinical practice and management of those patients who require fertility-sparing treatment.

Fertility Preservation in Children and Adolescents

Fertility preservation is the process by which either oocytes (eggs) or sperm undergo an intervention to preserve their use for future attempts at conception. Consideration of fertility preservation in the pediatric and adolescent population is important, as future childbearing is usually a central life goal. For postpubertal girls, both oocyte and embryo cryopreservation are standard of care and for postpubertal boys, sperm cryopreservation continues to be recommended. Although all the risks are unknown, it appears that fertility preservation in most cases does not worsen prognosis, allows for the birth of healthy children, and does not increase the chance of recurrence.

Transplantation of ovarian tissue

Since the first live birth after orthotopic transplantation of frozen-thawed ovarian tissue, >40 babies have been born. It is time to consider fertility preservation in women as one of the foremost challenges of the next decade and to offer women facing the risk of induced or iatrogenic premature menopause the best chances of becoming mothers. Heterotopic transplantation has also been attempted, with consistent restoration of endocrine function; nonetheless, its clinical value remains questionable as it may not provide an optimal environment for follicular development, possibly because of differences in temperature, pressure, paracrine factors and blood supply. Finally, orthotopic allo-transplantation of fresh human ovarian tissue has been successfully attempted between monozygotic twins and also between genetically different sisters. The next step in this field will be the development of an artificial ovary, using, as a support, a biodegradable scaffold made of an alginate matrigel matrix onto which isolated preantral follicles and ovarian cells can be grafted.

Fertility preservation in female cancer patients: An overview

Fertility preservation is becoming increasingly important to improve the quality of life in cancer survivors. Despite guidelines suggesting that discussion of fertility preservation should be done prior to starting cancer therapies, there is a lack of implementation in this area. A number of techniques are available for fertility preservation, and they can be used individually or together in the same patient to maximize efficiency. Oocyte and embryo cryopreservation are now established techniques but have their limitations. Ovarian tissue cryopreservation though considered experimental at present, has a wider clinical application and the advantage of keeping the fertility window open for a longer time. Both chemotherapy and radiotherapy have a major impact on reproductive potential and fertility preservation procedures should be carried out prior to these treatments. The need for fertility preservation has to be weighed against morbidity and mortality associated with cancer. There is thus a need for a multidisciplinary collaboration between oncologists and reproductive specialists to improve awareness and availability.

[Cryoconservation of ovarian tissue: indications and outcome of the patients]

OBJECTIVES

Ovarian Tissue Cryopreservation (OTC) is a very promising approach of fertility preservation for women and young patients who have to follow gonadotoxic treatments (chemotherapy, radiotherapy…). The aim of this study was to analyse the indications and the outcomes of the patients who had OTC in our center during the last 17 years.

PATIENTS AND METHODS

The study is retrospective. Forty-six patients, who underwent OTC in the Laboratory of Reproductive Biology of the University Hospital of Clermont-Ferrand, between January 1997 and December 2009, were included.

RESULTS

The average age on the day of ovarian tissue harvesting was 19.5 years. Fifty-two percent of the patients were minor. In order of decreasing frequency, the diseases for which OTC has been proposed were hematologic, ovarian tumors, sarcoma ou PNET and breast neoplasia. In 93.5 %, the harvesting of ovarian cortex was performed by laparoscopy. After OTC, 82.6 % of the patients were treated by chemotherapy. A bone marrow transplant was performed for 48 % of the study patients. At the time of data collection, 57 % of the patients who had evaluation of their ovarian function presented premature ovarian failure. Eight patients had one or more pregnancies after treatment. It was a natural pregnancy for five of them. The three others were obtained by medically assisted procreation (in vitro fertilization and oocyte donation).

DISCUSSION AND CONCLUSION

We report a long-term follow-up of patients treated in our center for OTC. The originality of our study is to evaluate all aspects of OTC from the decision to propose the patients an OTC to their outcomes several years after the ovarian tissue harvesting. It is therefore a multidisciplinary approach both oncology, gynecological and pediatric whereas OTC is often considered restrictively in the literature. Finally, it seems to be essential to establish a specific medical care for these patients. This monitoring will allow an adequate assessment of pubertal development and ovarian function, management of estrogen deficiency and secondary infertility, supporting patients in their desire for motherhood.

Ovarian tissue collection for cryopreservation in pediatric age: laparoscopic technical tips

As the number of young girls subjected to chemo and radiotherapy is steadily increasing it is our duty to try to preserve their future fertility and ovarian function. A possibility is to collect ovarian samples, cryopreserve them and reimplant the tissue when the treatments are over. We report our 11 year experience with the use of laparoscopy to collect ovarian tissue samples. In particular we focus on the details of the surgical technique. The procedure was performed in 54 patients affected by malignancies or pathologies requiring chemo or radiotherapy, with good results. Cryopreservation seems to be a good option to preserve future fertility although it is still an experimental method.

Ovarian tissue cryopreservation: a committee opinion

Ovarian tissue cryopreservation is an option to preserve reproductive potential in patients who must urgently undergo aggressive chemotherapy and/or radiotherapy or who have other medical conditions requiring treatment that may threaten ovarian function and subsequent fertility. Ovarian tissue cryopreservation may be the only option available to prepubertal girls undergoing such treatments. However, these techniques are still considered to be experimental. This document outlines the current technology, clinical outcomes, and risks of ovarian tissue cryopreservation and recommendations for clinical applications. This document and the document "Mature Oocyte Cryopreservation: A Guideline" published in 2013 (Fertil Steril 2013;99:37-43) replace the document "Ovarian Tissue and Oocyte Cryopreservation" last published in 2008 (Fertil Steril 2008;90:S241-6).