Ovarian tissue cryopreservation for patients with premature ovary insufficiency caused by cancer treatment: optimal protocol

Impact of oxidative stress induced by heavy metals on ovarian function

As a crucial organ of the female reproductive system, the ovary has both reproductive and endocrine functions. Oxidative stress refers to an increase in intracellular reactive oxygen species (ROS), which play a role in the normal physiological activity of the ovary. However, excessive ROS can cause damage to the ovary. With the advancement of human industrial activities, heavy metal pollution has become increasingly severe. Heavy metals cause oxidative stress through both direct and indirect mechanisms, leading to changes in signal transduction pathways that damage the ovaries. This review aims to outline the adverse effects of oxidative stress on the ovaries triggered by heavy metals such as copper, arsenic, cadmium, mercury, and lead. The detrimental effects of heavy metals on ovaries include follicular atresia and decreased estrogen production in experimental animals, and they also cause premature ovarian insufficiency in women. Additionally, this review discusses the role of antioxidants, provides some treatment methods, summarizes the limitations of current research, and offers perspectives for future research directions.

Mitochondria-targeted antioxidant mitoquinone mitigates vitrification-induced damage in mouse ovarian tissue by maintaining mitochondrial homeostasis via the p38 MAPK pathway

OBJECTIVE

Ovarian tissue cryopreservation has become a promising alternative for fertility preservation in cancer patients, allowing ovarian tissue to be stored for future autotransplantation. Oxidative stress damage occurring during the cryopreservation process may impact tissue quality and function. This study aims to investigate the protective effects and potential mechanisms of Mitoquinone (MitoQ), a mitochondria-targeted derivative of the antioxidant ubiquinone, during the vitrification of ovarian tissue in mice.

METHODS

KGN cells were treated with various concentrations (0.1, 1, 10, and 50 μM) of MitoQ to determine the optimal concentration. Female ICR mice were divided into three groups: control, conventional vitrification, and MitoQ-supplemented vitrification. Ovarian samples were cryopreserved, thawed, and assessed for tissue morphology using Hematoxylin and Eosin (H&E) staining, and mitochondrial changes using immunofluorescence, transmission electron microscopy, and Western blot analysis. RNA sequencing (RNA-seq) was employed to explore potential protective mechanisms. Autotransplantation experiments were conducted, and the long-term effects of MitoQ on ovarian function were evaluated by counting follicle numbers through H&E staining and measuring serum estradiol and AMH levels using ELISA.

RESULTS

MitoQ at 1 μM was found to be the optimal concentration for maintaining follicular morphology after vitrification. It effectively reduced mitochondrial oxidative damage, preserved mitochondrial morphology, and regulated the expression of mitochondrial dynamics proteins (Drp1 and Mfn2). RNA-seq and Western blot analyses revealed that MitoQ inhibited the p38 MAPK pathway, thereby reducing apoptosis. Additionally, autotransplantation experiments showed that MitoQ treatment significantly increased follicle counts, estradiol (E2), and anti-Müllerian hormone (AMH) levels compared to conventional vitrification.

CONCLUSIONS

MitoQ effectively mitigates vitrification-induced oxidative damage, maintains mitochondrial homeostasis, and preserves both follicular reserve and endocrine function. These findings suggest that MitoQ is a valuable adjunct in ovarian tissue cryopreservation and could significantly improve fertility preservation outcomes for cancer patients.

Ovarian tissue cryopreservation for an 8 year old girl after hematopoietic stem cell transplantation in China: case report and literature review

BACKGROUND

Preconditioning before hematopoietic stem cell transplantation (HSCT) severely damages ovarian function, resulting in infertility and premature ovarian insufficiency (POI) in young women and girls. Ovarian function and fertility preservation before HSCT is crucial. In China, many patients miss this opportunity, highlighting the need for ovarian function and fertility preservation after HSCT. Ovarian tissue cryopreservation (OTC) is a standard method for fertility preservation and protecting ovarian function. The objective of this case report is to report a case of OTC performed on an 8-year-old girl after HSCT, and present a review about the necessity and feasibility of ovarian preservation after HSCT.

CASE

An 8-year-old girl required a second HSCT due to a relapse of dermatomyositis. Before the procedure, she visited our center for OTC. Hormonal assessments showed FSH 1.17 IU/L, LH 0.00 IU/L, E2 < 11.80 pg/ml, and AMH 0.81 ng/ml. Pelvic ultrasound revealed bilateral ovarian sizes of approximately 1.5 × 0.7 × 0.7 cm and 1.6 × 0.9 × 0.7 cm, with 10 and 4 visible follicles, respectively. We proceeded with OTC, surgically retrieving the entire left ovary via laparoscopy. Seven ovarian cortical slices were cryopreserved by slow freezing, with an average of 1079 follicles in per 2 mm diameter cortical tissue slice.

CONCLUSION

Patients who miss fertility preservation before HSCT should consult fertility preservation and gynecological endocrinology experts as early as possible after HSCT and undergo regular follow-up. If clinical evidence indicates residual ovarian function, fertility protection measures should be discussed promptly. OTC should be assessed as a successful option for women after HSCT.

Standardization for ovarian tissue cryopreservation and transplantation in China

Ovarian tissue cryopreservation and transplantation is one of the most advanced and promising fertility preservation methods. Prior to any procedure that may lead to a toxic ovarian injury (such as chemotherapy or radiotherapy), a portion of the ovary is removed and cryopreserved. At an appropriate time, after toxic therapy is concluded, the cryopreserved ovarian tissue is then thawed and transplanted back to the patient when conditions permit. This technique can not only preserve female fertility but also restore ovarian endocrine function. However, there is no standardization for ovarian tissue cryopreservation and transplantation in China. In order to promote the standardized development of ovarian tissue cryopreservation technology in the whole country, it is urgent to establish the standard of this technology.

Ovarian microenvironment: challenges and opportunities in protecting against chemotherapy-associated ovarian damage

BACKGROUND

Chemotherapy-associated ovarian damage (CAOD) is one of the most feared short- and long-term side effects of anticancer treatment in premenopausal women. Accumulating detailed data show that different chemotherapy regimens can lead to disturbance of ovarian hormone levels, reduced or lost fertility, and an increased risk of early menopause. Previous studies have often focused on the direct effects of chemotherapeutic drugs on ovarian follicles, such as direct DNA damage-mediated apoptotic death and primordial follicle burnout. Emerging evidence has revealed an imbalance in the ovarian microenvironment during chemotherapy. The ovarian microenvironment provides nutritional support and transportation of signals that stimulate the growth and development of follicles, ovulation, and corpus luteum formation. The close interaction between the ovarian microenvironment and follicles can determine ovarian function. Therefore, designing novel and precise strategies to manipulate the ovarian microenvironment may be a new strategy to protect ovarian function during chemotherapy.

OBJECTIVE AND RATIONALE

This review details the changes that occur in the ovarian microenvironment during chemotherapy and emphasizes the importance of developing new therapeutics that protect ovarian function by targeting the ovarian microenvironment during chemotherapy.

SEARCH METHODS

A comprehensive review of the literature was performed by searching PubMed up to April 2024. Search terms included 'ovarian microenvironment' (ovarian extracellular matrix, ovarian stromal cells, ovarian interstitial, ovarian blood vessels, ovarian lymphatic vessels, ovarian macrophages, ovarian lymphocytes, ovarian immune cytokines, ovarian oxidative stress, ovarian reactive oxygen species, ovarian senescence cells, ovarian senescence-associated secretory phenotypes, ovarian oogonial stem cells, ovarian stem cells), terms related to ovarian function (reproductive health, fertility, infertility, fecundity, ovarian reserve, ovarian function, menopause, decreased ovarian reserve, premature ovarian insufficiency/failure), and terms related to chemotherapy (cyclophosphamide, lfosfamide, chlormethine, chlorambucil, busulfan, melphalan, procarbazine, cisplatin, doxorubicin, carboplatin, taxane, paclitaxel, docetaxel, 5-fluorouraci, vincristine, methotrexate, dactinomycin, bleomycin, mercaptopurine).

OUTCOMES

The ovarian microenvironment shows great changes during chemotherapy, inducing extracellular matrix deposition and stromal fibrosis, angiogenesis disorders, immune microenvironment disturbance, oxidative stress imbalances, ovarian stem cell exhaustion, and cell senescence, thereby lowering the quantity and quality of ovarian follicles. Several methods targeting the ovarian microenvironment have been adopted to prevent and treat CAOD, such as stem cell therapy and the use of free radical scavengers, senolytherapies, immunomodulators, and proangiogenic factors.

WIDER IMPLICATIONS

Ovarian function is determined by its 'seeds' (follicles) and 'soil' (ovarian microenvironment). The ovarian microenvironment has been reported to play a vital role in CAOD and targeting the ovarian microenvironment may present potential therapeutic approaches for CAOD. However, the relation between the ovarian microenvironment, its regulatory networks, and CAOD needs to be further studied. A better understanding of these issues could be helpful in explaining the pathogenesis of CAOD and creating innovative strategies for counteracting the effects exerted on ovarian function. Our aim is that this narrative review of CAOD will stimulate more research in this important field.

REGISTRATION NUMBER

Not applicable.

Kisspeptin decreases the adverse effects of human ovarian vitrification by regulating ROS-related apoptotic occurrences

Kisspeptin is characterized as a neuropeptide with a pivotal function in female and male infertility, and its antioxidant properties have been demonstrated. In this study, the effects of kisspeptin on the improvement of the vitrification and thawing results of human ovarian tissues were investigated. In this work, 12 ovaries from patients who underwent hysterectomy were collected laparoscopically, and then 32 samples from each of their tissues were taken. Haematoxylin and eosin (H&E) staining was performed to check the normality of the ovarian tissue and, subsequently, the samples were allocated randomly into four groups, including: (1) fresh (control), (2) vitrification, (3) vitrified + 1 μM kisspeptin, and (4) vitrified + 10 μM kisspeptin groups. After vitrification, thawing, and tissue culture processes, H&E staining for tissue quality assessment, terminal deoxynucleotidyl transferase dUTP nick end labelling assay for apoptosis evaluation, and malondialdehyde (MDA), superoxide dismutase (SOD), and ferric reducing ability of plasma tests for oxidative stress appraisal were carried out. Our histological results showed incoherency of ovarian tissue morphology in the vitrification group compared with other groups. Other findings implicated increased apoptosis rate and MDA concentration and reduced SOD activity and total antioxidant capacity (TAC) in the vitrification group compared with the control group (P < 0.05). Moreover, decreased apoptosis rate and MDA concentration, and increased TAC and SOD function were observed in the vitrification with kisspeptin groups (1 μM and 10 μM) compared with the vitrified group (P < 0.05). Our reports express that kisspeptin is an effective agent to overcome the negative effects of vitrification by regulating reactive oxygen species-related apoptotic processes.

Ovarian tissue cryopreservation and transplantation: a review on reactive oxygen species generation and antioxidant therapy

Cancer is the leading cause of death worldwide. Fortunately, the survival rate of cancer continues to rise, owing to advances in cancer treatments. However, these treatments are gonadotoxic and cause infertility. Ovarian tissue cryopreservation and transplantation (OTCT) is the most flexible option to preserve fertility in women and children with cancer. However, OTCT is associated with significant follicle loss and an accompanying short lifespan of the grafts. There has been a decade of research in cryopreservation-induced oxidative stress in single cells with significant successes in mitigating this major source of loss of viability. However, despite its success elsewhere and beyond a few promising experiments, little attention has been paid to this key aspect of OTCT-induced damage. As more and more clinical practices adopt OTCT for fertility preservation, it is a critical time to review oxidative stress as a cause of damage and to outline potential ameliorative interventions. Here we give an overview of the application of OTCT for female fertility preservation and existing challenges; clarify the potential contribution of oxidative stress in ovarian follicle loss; and highlight potential ability of antioxidant treatments to mitigate the OTCT-induced injuries that might be of interest to cryobiologists and reproductive clinicians.

Ovarian tissue cryopreservation in the pediatric with rare diseases- experience from China's first and the largest ovarian tissue cryobank

Background

There is limited information about the efficacy of ovarian tissue cryopreservation (OTC) in children. In the present study, we report eight patients with rare diseases who underwent OTC in China's first and largest ovarian tissue cryobank.

Procedure

Data from girls with rare diseases who underwent OTC between September 2020 and November 2022 were retrospectively analyzed. We also compared the number of cryopreserved cortex pieces, follicle number, and AMH in those with rare diseases and age-matched children with non-rare diseases who also underwent OTC in our cryobank.

Results

The median age of the children was 5.88 ± 3.52 (range 2-13) years old. Unilateral oophorectomy was undertaken via laparoscopy in all of the children. The diseases in the 8 patients were: 4 mucopolysaccharidoses (MPS I two cases, IVA two cases), 1 Diamond-Blackfan anemia (DBA), 1 Fanconi anemia (FA), 1 hyperimmunoglobulin E syndrome (HIES), 1 Niemann-Pick disease. The number of cryopreserved cortex pieces was 17.13 ± 6.36, and the follicle count per 2 mm biopsy was 447.38 ± 524.35. No significant difference in age, the count of cryopreserved cortex pieces, follicle number per 2 mm biopsy, and AMH level was seen between the 20 children with non-rare diseases and those with rare diseases.

Conclusions

The reports help practitioners counsel girls with rare diseases about fertility preservation. The demand for OTC in pediatrics will likely grow as a standard of care.

The Trends and Hotspots in Premature Ovarian Insufficiency Therapy from 2000 to 2022

This study aims to map the knowledge structure and themes trends of primary ovarian insufficiency (POI) therapy to help researchers rapidly master the hotspots and prospects of POI therapy from the increasing number of publications. The literature search and bibliometric analyses were performed by using Web of Science Core Collection and VOSviewer. Annual publications from 2000 to 2022 continued to increase with some fluctuations. The most productive country, organization, and journal were the USA, Shanghai Jiao Tong University, and Human Reproduction, respectively. Harvard University was the organization with the highest citation. Fertility and Sterility and Nelson, L.M. were the most influential journal and author, respectively. Seven clusters separated by keywords association showed the extensive scope of POI therapy. The hotspots of POI therapy were hormone replacement therapy and fertility preservation, and the innovative treatment strategies including in vitro activation and mesenchymal stem cells had development potential. In addition, our result showed that the high-cited articles were published in journals with high impact factors. The paper provides a comprehensive overview of the development and hotspots of POI therapy, allowing researchers to recognize the current status and future directions of POI therapy.

Effects of hypoxia-preconditioned HucMSCs on neovascularization and follicle survival in frozen/thawed human ovarian cortex transplanted to immunodeficient mice

Background

The massive loss of follicles in the early stage of ovarian tissue transplantation is considered a significant restriction to the efficacy of ovarian tissue cryopreservation (OTC) and transplantation (OT). The use of mesenchymal stem cells (MSCs) before transplantation of ovarian fragments shortened the hypoxic period and boosted neovascularization. Hypoxia-preconditioned MSCs can enhance the potential of angiogenesis. Can hypoxia-preconditioned human umbilical cord mesenchymal stem cell (HucMSCs) and ovarian tissue co-xenotransplantation improve more neovascularization and subsequently more follicle survival in human ovarian tissue?

Methods

Frozen-thawed cortical pieces from 4 patients were transplanted into the bilateral renal capsule of immune-deficient nude mice without HucMSCs or normoxia/hypoxia-preconditioned HucMSCs. Sixty-four mice were randomly distributed into 4 groups. In each group, the mice were euthanized for blood and/or graft retrieval on post-transplantation days 3 (n = 8) and 7 (n = 8), respectively. Non-grafted frozen-thawed ovarian fragment was taken for non-grafted control. Grafts were histologically processed and analysed for follicle density and atretic follicles by HE, neovascularization by CD34 and CD31 immunohistochemical staining, primordial follicle growth by Ki67 staining, and apoptosis of stromal cell and follicles by immunofluorescence using TUNEL. The ROS and TAC levels of grafted and non-grafted tissue were assessed. We evaluated the protein expression of HIF1α, VEGFA, pAkt, Akt, and GDF9 in grafted and non-grafted ovarian tissue. E2, Prog, AMH, and FSH levels in the plasma of mice were measured after 3 and 7 days of OT.

Results

Hypoxia-preconditioned HucMSCs positively protect the grafted ovarian tissue by significantly decreasing the apoptosis and increasing higher expression of CD31, CD34, and VEGFA for earlier angiogenesis. They are crucial to preserving the resting primordial follicle pool by modulation of follicle death.

Conclusion

This is the first study to demonstrate that co-transplantation of hypoxia-preconditioned HucMSC with ovarian tissue improved earlier vascularization of ovarian grafts in the early post-grafting period, which correlates with increased follicle survival and reduced apoptosis. The HIF1α/VEGFA signal pathways may play an important role in elucidating the mechanisms of action of hypoxia-preconditioned HucMSCs with regard to OT and clinical implementation.

Investigation of the optimal culture time for warmed bovine ovarian tissues before transplantation

Ovarian tissue cryopreservation by vitrification is an effective technique, but there are still many unresolved issues related to the procedure. The aim of this study was to investigate the optimal culture time of post-warmed ovarian tissues and their viability before ovarian tissue transplantation. The bovine ovarian tissues were used to evaluate the effect of post-warming culture periods (0, 0.25, 0.5, 1, 2, 5 and 24 hours) in the levels of residual cryoprotectant, LDH release, ROS generation, gene and protein abundance, and follicle viability and its mitochondrial membrane potential. Residual cryoprotectant (CPA) concentration decreased significantly after 1 hour of culture. The warmed ovarian tissues that underwent between 0 to 2 hours of culture time showed similar LDH and ROS levels compared to fresh non-frozen tissues. The AMH transcript abundance did not differ in any of the groups. No increase in the relative transcript abundance and protein level of Caspase 3 and Cleaved-Caspase 3, respectively, in the first 2 hours of culture after warming. On the other hand, an increased protein level of double stranded DNA breaks (gamma-H2AX) was observed in post-warmed tissues disregarding the length of culture time, and a temporary reduction in pan-AKT was detected in post-warming tissues between 0 to 0.25 hours of culture time. Prolonged culture time lowered the percentage of viable follicles in warmed tissues, but it did not seem to affect the follicular mitochondrial membrane potential. In conclusion, 1 to 2 hours of culture time would be optimal for vitrified-warmed tissues before transplantation.

Effectiveness of Clinical-Grade Chondroitin Sulfate and Ascorbic Acid in Mitigating Cryoprotectant Toxicity in Porcine Articular Cartilage

High concentrations of cryoprotective agents (CPAs) are required to achieve successful vitrification of articular cartilage; however, CPA cytotoxicity causes chondrocyte death. To reduce CPA toxicity, supplementation with research-grade additives, in particular chondroitin sulfate (CS) and ascorbic acid (AA), have previously been shown to improve chondrocyte recovery and metabolic function after exposure to CPAs at hypothermic conditions. However, it is necessary to evaluate the pharmaceutical equivalent clinical grade of these additives to facilitate the supplementation of additives into future vitrification protocols, which will be designed for vitrifying human articular cartilage in tissue banks. We sought to investigate the effectiveness of clinical-grade CS, AA, and N-acetylcysteine (NAC) in mitigating toxicity to chondrocytes during CPA exposure and removal, and determine whether a combination of two additives would further improve chondrocyte viability. We hypothesized that clinical-grade additives would exert chondroprotective effects comparable to those of research-grade additives, and that this protective effect would be enhanced if two additives were combined when compared with a single additive. The results indicated that both clinical-grade and research-grade additives significantly improved cell viability (p < 0.10) compared with the negative control (CPA with no additives). CS, AA, and NAC+AA increased cell viability significantly (p < 0.10) compared with the negative control. However, NAC, NAC+CS, and CS+AA did not improve cell viability when compared with the negative control (p > 0.10). We demonstrated that supplementation with clinical-grade CS or AA significantly improved chondrocyte viability in porcine cartilage subjected to high CPA concentrations, whereas supplementation with clinical-grade NAC did not benefit chondrocyte viability. Supplementation with clinical-grade additives in CPA solutions can mitigate CPA toxicity, which will be important in translating previously developed effective protocols for the vitrification of articular cartilage to human tissue banks.

N-Acetylcysteine improves oocyte quality through modulating the Nrf2 signaling pathway to ameliorate oxidative stress caused by repeated controlled ovarian hyperstimulation

CONTEXT

N -acetyl-cysteine (NAC) is a potent antioxidant that can be used for many gynecological diseases such as polycystic ovary syndrome and endometriosis. Controlled ovarian hyperstimulation (COH) is a critical step in infertility treatment. Our previous clinical studies have shown that repeated COH led to oxidative stress in follicle fluid and ovarian granulosa cells.

AIMS

In this study, we investigated whether NAC could inhibit oxidative stress in mice caused by repeated COH and improve the mitochondrial function of oocytes.

METHODS

Female Institute of Cancer Research (ICR) mice were randomly assigned into three groups: normal group, model (repeated COH) group, NAC group. We examined the morphology, number and quality of mitochondria. The mechanism of regulation of nuclear factor erythroid 2-related factor 2 (Nrf2) by NAC to ameliorate oxidative stress was also investigated.

KEY RESULTS

Repeated COH caused oxidative damage in ovaries and oocytes and decreased oocyte quality, while NAC prevented oxidative damage and increased oocyte mitochondrial function. In in vitro experiments, it was verified that NAC can promote the nuclear translocation of Nrf2, which transcriptionally activates the expression of superoxide dismutase and glutathione peroxidase, which removed excessive reactive oxygen species that causes mitochondria damage.

CONCLUSIONS

The results suggest that NAC raises mitochondrial function in oocytes and improves oocyte quality through decreasing oxidative stress in mice with repeated COH. The underlying mechanism is related to the regulation of the Nrf2 signaling pathway.

IMPLICATION

This study provides a meaningful foundation for the future clinical application of NAC during repeated COH.

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

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

SYSTEMATIC REVIEW REGISTRATION

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

Analysis of Fertility Preservation by Ovarian Tissue Cryopreservation in Pediatric Children in China

BACKGROUND

Ovarian tissue cryopreservation (OTC) is the only method of fertility preservation (FP) in prepubertal girls, but the experience remains limited. This study investigates the effectiveness and feasibility of FP of OTC in children facing gonadotoxicity treatment in Chinese first ovarian tissue cryobank.

PROCEDURE

OTC and evaluation of 49 children ≤14 years old in the cryobank of Beijing Obstetrics and Gynecology Hospital, Capital Medical University, from July 2017 to May 19, 2022, were analyzed retrospectively. We compared children's general characteristics, follicle numbers, and hormone levels with and without chemotherapy before OTC.

RESULTS

The age of 49 children at the time of OTC was 7.55 (1-14) years old. There were 23 cases of hematological non-malignant diseases, eight cases of hematological malignant diseases, four cases of gynecological malignant tumors, one case of neurological malignant tumors, one case of bladder cancer, five cases of sarcoma, three cases of mucopolysaccharidosis, one case of metachromatic leukodystrophy, two cases of dermatomyositis, one case of Turner's syndrome. The median follicular count per 2-mm biopsy was 705. Age and AMH were not correlated (r = 0.084, P = 0.585). Age and follicle count per 2-mm biopsy was not correlated (r = -0.128, P = 0.403). Log10 (follicle count per 2-mm biopsy) and Log10 (AMH) were not correlated (r = -0.118, P = 0.456). Chemotherapy before OTC decreased AMH levels but had no significant effect on the number of follicles per 2-mm biopsy.

CONCLUSIONS

OTC is the only method to preserve the fertility of prepubertal girls, and it is safe and effective. Chemotherapy before OTC is not a contraindication to OTC.

Role of Klotho as a Modulator of Oxidative Stress Associated with Ovarian Tissue Cryopreservation

Ovarian tissue cryopreservation is the only option for preserving fertility in adult and prepubertal cancer patients who require immediate chemotherapy or do not want ovarian stimulation. However, whether ovarian tissue cryopreservation can ameliorate follicular damage and inhibit the production of reactive oxygen species in cryopreserved ovarian tissue remains unclear. Oxidative stress is caused by several factors, such as UV exposure, obesity, age, oxygen, and cryopreservation, which affect many of the physiological processes involved in reproduction, from maturation to fertilization, embryonic development, and pregnancy. Here, freezing and thawing solutions were pre-treated with N-acetylcysteine (NAC) and klotho protein upon the freezing of ovarian tissue. While both NAC and klotho protein suppressed DNA fragmentation by scavenging reactive oxygen species, NAC induced apoptosis and tissue damage in mouse ovarian tissue. Klotho protein inhibited NAC-induced apoptosis and restored cellular tissue damage, suggesting that klotho protein may be an effective antioxidant for the cryopreservation of ovarian tissue.

Ovarian tissue cryopreservation in a patient with breast cancer during pregnancy: a case report

BACKGROUND

Fertility preservation using ovarian tissue cryopreservation (OTC) in patients with certain diseases, especially those needing chemo- or radiotherapy, is becoming routine in various Western countries. Our hospital is the first and until now the only centre in China to use this method. The question of whether treatment of breast cancer during pregnancy (PrBC) should be similar to non-pregnant young patients with breast cancer is controversial. To our knowledge, this is the first report worldwide to use OTC as fertility preservation for PrBC.

CASE PRESENTATION

During the 29th week of pregnancy, a 24-year-old woman underwent needle aspiration cytology of a left breast tumour. Ultrasound and cytology revealed BI-RADS 4a grade. Oncologists recommended termination of the pregnancy. Caesarean section was performed at week 32, and ovarian tissue samples were collected for OTC to preserve fertility and ovarian endocrine function. Twenty-three ovarian cortex slices were cryopreserved. It is estimated that 13,000 follicles were cryopreserved. Breast nodules and sentinel lymph node biopsy suggested invasive micropapillary carcinoma. Neoadjuvant chemotherapy was started within 1 week after diagnosis. After six courses of neoadjuvant chemotherapy, targeted drug therapy and goserelin acetate, left mastectomy and left axillary lymph node dissection were performed. In total, 23 doses of radiotherapy, eight trastuzumab targeted therapy treatments, and 17 pertuzumab + trastuzumab double targeted therapy treatments were performed after breast cancer surgery. Until now, more than 2 years after delivery, the ovarian function still is good, and no signs of a negative impact of OTC have been observed. Goserelin acetate injections, administered every 28 days, are planned to last for the next 5 years. In addition, endocrine therapy with anastrozole was started after breast cancer surgery and also is scheduled for 5 years.

CONCLUSION

OTC for fertility preservation in patients with PrBC does not delay breast surgery, radiotherapy or chemotherapy, which is essential for effective treatment of breast cancer. We assess this method as a promising fertility preservation method which was used here for the first time worldwide in a patient who developed breast cancer during pregnancy.

Review of ovarian tissue cryopreservation techniques for fertility preservation

Ovarian failure and ovarian malfunction are among major fertility problems in women of reproductive age (18-35 years). It is known that various diseases, such as ovarian cancer and premature ovarian failure, besides certain treatments, such as radiotherapy and chemotherapy of other organs, can affect the normal process of folliculogenesis and cause infertility. In recent years, various procedures have been proposed for the treatment of infertility. One of the newest methods is the use of cryopreservation ovarian fragments after cancer treatment. According to some studies, this method yields very satisfactory results. Although ovarian tissue cryopreservation (OTC) is an accepted technique of fertility preservation, the relative efficacy of cryopreservation protocols remains controversial. Considering the controversies about these methods and their results, in this study, we aimed to compare different techniques of ovarian cryopreservation and investigate their advantages and disadvantages. Reviewing the published articles may be possible to identify appropriate strategies and improve infertility treatment in these patients.

N-acetyl-cysteine and the control of oxidative stress during in vitro ovarian follicle growth, oocyte maturation, embryo development and cryopreservation

Oxidative stress is generated by an imbalance between reactive oxygen species (ROS) formation and cellular defense mechanisms. To reduce cellular damage caused by ROS in vivo or in vitro, N-acetyl-cysteine (NAC) is converted into metabolites that have the capacity of stimulating synthesis of glutathione (GSH) which functions directly as free radical scavengers. The NAC antioxidant potential evaluated to the greatest extent is the indirect action of NAC, as a precursor of GSH, with glutathione being the primary antioxidant in cells. During long-term preantral follicle culture, NAC has a synergic action with FSH and an important function in sustaining preantral follicle growth and follicle-cell viability in vitro. The NAC inclusion in in vitro maturation medium for cumulus-oocyte complexes (COC) leads to protection of oocytes from damage induced by heat stress, reductions in ROS, and increases in cumulus cell expansion. Developing embryos are susceptable to oxidative stress because of susceptability to cellular structure damage and not having well-developed defense mechanisms. Results from various indicate there are beneficial effects of NAC on embryonic development by increasing GSH biosynthesis and regulating cell proliferation. In addition, NAC is also an effective antioxidant during cryopreservation of ovarian follicles, oocytes and embryos, because inclusion of NAC in preservation medium leads to improvements in mitochondrial function and cell viability, and reductions in ROS and cellular apoptosis. In this review, there is evaluation of mechanisms of action of NAC and beneficial effects during in vitro culture of preantral follicles, as well as oocyte maturation, embryonic development and cryopreservation.

Long-time low-temperature transportation of human ovarian tissue before cryopreservation

RESEARCH QUESTION

Can the low-temperature transport time of removed human ovarian tissue be prolonged until cryopreservation?

DESIGN

Fresh ovarian cortex from nine premenopausal patients was either slow-frozen immediately or stored at 4°C for 24 or 48 h before slow-freezing. The fresh and frozen-thawed biopsies were evaluated by follicle counting via calcein staining, histologic analyses via haematoxylin and eosin staining, and apoptosis via terminal deoxynucleotidyl transferase-mediated dUDP nick-end labelling (TUNEL). The fresh cortex was assessed by reactive oxygen species (ROS) and total antioxidant capacity (TAC) assay to detect oxidative stress. The frozen-thawed cortex biopsies were also evaluated by quantitative PCR for messenger RNA (mRNA) expression of BCL-2, BAX, TNFa, HIF-1a, BMP15 and GDF9, and Western blot for detection of BCL-2, BMP15, GDF9 and CASPASE-3. The frozen-thawed cortex was cultured in vitro for 4 days, anti-Müllerian hormone and glucose were assessed in the supernatant, and ROS and TAC assay detected any oxidative stress in the cortex.

RESULTS

In the fresh cortex, there were no significant differences between the three groups. In the frozen-thawed cortex, there were no significant differences between the three groups regarding follicle viability, TUNEL, mRNA expression of TNFa, HIF-1a or BMP15. GDF9 mRNA and BAX/BCL-2 were lower and higher at 48 h than at 0 h, respectively. However, the protein expression of BCL-2, CASPASE-3, GDF9 and BMP15 were no different. In the cultured cortex, ROS, TAC and glucose uptake were no different across the three groups.

CONCLUSION

Ovarian tissue transportation was validated for 24 h in the procedure used in clinical practice. This study showed that 4-8°C transportation for 24 or 48 h does not seem to damage the ovarian tissue. However, ovarian tissue transportation beyond 48 h needs to be further studied for conclusions to be made.

How much total ovarian tissue can be removed without compromising ovarian function? An animal study

OBJECTIVE

Removal of ovarian tissue is a new option for fertility preservation for certain cancer patients in China. The aim was to investigate the impact of stepwise removed tissue on hormone levels and follicles in rats.

METHODS

Six to ten-week old rats were divided into six groups (% total ovarian tissue): 1 = control (100%), 2 (75%), 3 (50%), 4 (25%), 5 (12.5%), 6 (0%, bilateral ovariectomy). Blood test was carried out fortnightly to assess estradiol (E2), progesterone (P), follicle-stimulating hormone (FSH), anti-Müllerian hormone (AMH), and inhibin B (INHB). Ovaries are obtained from surgical resections and from rats sacrificed after 12 weeks.

RESULTS

During 12 weeks, groups 4, 5, and 6 had higher FSH and lower AMH and INHB values compared to control (p< .05), but in group 4 E2 and P was not significantly different from control (p> .05). All ovarian function parameters stopped in groups 5 and 6. Follicle morphology was not significantly different between baseline and 12 weeks after surgery in groups 1-5.

CONCLUSIONS

For the first time, we demonstrated that even up to 75% of total ovarian tissue can be removed without impact on E2 and P production in rats, which, if confirmed in women, would mean that hazardous (or possibly contraindicated in cancer patients) hormone therapy is not required to avoid the negative consequences of hormone depletion.