Ovarian tissue cryopreservation and transplantation: a review

Short-Term PTEN Inhibition Improves In Vitro Activation of Primordial Follicles, Preserves Follicular Viability, and Restores AMH Levels in Cryopreserved Ovarian Tissue From Cancer Patients

Introduction

In vitro activation and growth of primordial dormant follicles to produce fertilizable oocytes would provide a useful instrument for fertility preservation. The employment of Phosphatase and TENsin homolog (PTEN) inhibitors, in combination with Protein kinase B (Akt) stimulating molecules, has been previously employed to increase follicular activation through the stimulation of the PTEN-Akt pathway.

Methods

We aim to establish improved in vitro activation also for cancer patients whose ovarian tissue has already been cryopreserved. Fresh and previously cryopreserved human ovarian cortex were exposed to short-term, low-concentration and ovary-specific treatment with only a PTEN inhibitor.

Results

Our in vitro activation protocol enhances the activation mechanisms of primordial follicles in both fresh and cryopreserved samples, and enlarges growing populations without inducing apoptosis in either follicles or the surrounding stroma. Treatment augments estradiol secretion and restores the expression levels of the previously diminished Anti-Müllerian hormone by means of cryopreservation procedures. Genomic modulation of the relative expression of PTEN pathway genes was found in treated samples.

Conclusion

The in vitro activation protocol offers new alternatives for patients with cryopreserved tissue as it increases the pool of viable activated follicles available for in vitro growth procedures. The combination of ovarian tissue cryopreservation and in vitro activation of primordial follicles, the main ovarian reserve component, will be a major advancement in fertility preservation.

Basic fibroblast growth factor promotes macaque follicle development in vitro

Fertility preservation is an important type of frontier scientific research in the field of reproductive health. The culture of ovarian cortices to i) initiate primordial follicle growth and ii) procure developing follicles for later oocyte maturation is a promising fertility preservation strategy, especially for older women or cancer patients. At present, this goal remains largely unsubstantiated in primates because of the difficulty in attaining relatively large follicles via ovarian cortex culture. To overcome this hurdle, we cultured macaque monkey ovarian cortices with FSH, kit ligand (KL), basic fibroblast growth factor (bFGF), and/or epidermal growth factor (EGF). The various factors and factor combinations promoted primordial follicle development to different extents. Notably, both bFF (bFGF, 100 ng/ml and FSH, 50 ng/ml) and KF (KL, 100 ng/ml and FSH, 50 ng/ml) contributed to the activation of primordial follicles at day 12 (D12) of culture, whereas at D18, the proportions of developing follicles were significantly higher in the bFF and KF groups relative to the other treatment groups, particularly in the bFF group. Estradiol and progesterone production were also highest in the bFF group, and primary follicle diameters were the largest. Up until D24, the bFF group still exhibited the highest proportion of developing follicles. In conclusion, the bFGF–FSH combination promotes nonhuman primate primordial follicle developmentin vitro, with the optimal experimental window within 18 days. These results provide evidence for the future success of human ovarian cortex culture and the eventual acquisition of mature human follicles or oocytes for fertility restoration.

Is transplantation of a few leukemic cells inside an artificial ovary able to induce leukemia in an experimental model?

PURPOSE

To evaluate the tumor-inducing ability of a few leukemic cells xenotransplanted inside an artificial ovary.

METHODS

Ten and 100 BV-173 leukemic cells were embedded in a fibrin matrix along with 50,000 human ovarian stromal cells, and grafted to the peritoneal bursa of 5 and 5 SCID mice respectively. Four mice grafted with 3x10(6) leukemic cells in fibrin served as positive controls. At 20 weeks post-transplantation, the grafts, liver, spleen, blood and bone marrow were analyzed for the presence of leukemia by anti-CD79α IHC, flow cytometry (FC) and PCR.

RESULTS

All mice grafted with 3x10(6) cells developed peritoneal masses 4 weeks after xenotransplantation, and systemic disease was confirmed by IHC, PCR and FC. Among mice grafted with 10 or 100 leukemic cells, none showed any sign of leukemia after 20 weeks, and IHC, FC and PCR on the different recovered tissues all proved negative.

CONCLUSION

This study investigates the tumor-inducing potential of a few leukemic cells grafted inside an artificial ovary. Transplantation of 100 leukemic cells appears to be insufficient to induce leukemia after 20 weeks. These results in an immunodeficient xenografting model are quite reassuring. However, for clinical application, follicle suspensions must be purged of leukemic cells before grafting, as even the slightest risk should be avoided.

Preservation of tissue microstructure and functionality during freezing by modulation of cytoskeletal structure

Cryopreservation is one of the key enabling technologies for tissue engineering and regenerative medicine, which can provide reliable long-term storage of engineered tissues (ETs) without losing their functionality. However, it is still extremely difficult to design and develop cryopreservation protocols guaranteeing the post-thaw tissue functionality. One of the major challenges in cryopreservation is associated with the difficulty of identifying effective and less toxic cryoprotective agents (CPAs) to guarantee the post-thaw tissue functionality. In this study, thus, a hypothesis was tested that the modulation of the cytoskeletal structure of cells embedded in the extracellular matrix (ECM) can mitigate the freezing-induced changes of the functionality and can reduce the amount of CPA necessary to preserve the functionality of ETs during cryopreservation. In order to test this hypothesis, we prepared dermal equivalents by seeding fibroblasts in type I collagen matrices resulting in three different cytoskeletal structures. These ETs were exposed to various freeze/thaw (F/T) conditions with and without CPAs. The freezing-induced cell-fluid-matrix interactions and subsequent functional properties of the ETs were assessed. The results showed that the cytoskeletal structure and the use of CPA were strongly correlated to the preservation of the post-thaw functional properties. As the cytoskeletal structure became stronger via stress fiber formation, the ET's functionality was preserved better. It also reduced the necessary CPA concentration to preserve the post-thaw functionality. However, if the extent of the freezing-induced cell-fluid-matrix interaction was too excessive, the cytoskeletal structure was completely destroyed and the beneficial effects became minimal.

Total oxidative status of mouse vitrified pre-antral follicles with pre-treatment of alpha lipoic acid

Background: Cryopreservation of pre-antral follicles is a hopeful technique to preserve female fertility. The aim of the present study was to evaluate reactive oxygen species (ROS) and total antioxidant capacity (TAC) levels of mouse vitrified pre-antral follicles in the presence of alpha lipoic acid (ALA). Methods: Isolated pre-antral follicles (140–150 µm in diameter) were divided into vitrified–warmed and fresh groups. Each group was subjected to in vitro maturation with or without ALA for 12 days, followed by adding human chronic gonadotropin to induce ovulation. In vitro fertilization was performed to evaluate their developmental competence. In parallel, the amount of ROS and TAC were assessed after 0, 24, 48, 72, and 96 h of culture by 2',7'-dichlorofluorescin assay and ferric reducing/antioxidant power assay, respectively. Results: The respective rates of survival, antrum formation, and metaphase II oocytes were significantly higher in ALA-supplemented groups compared to the groups not treated with ALA. TAC and ROS levels were significantly decreased and increased, respectively during the culture period up to 96 h in the absence of ALA in both vitrified and non-vitrified samples. However, with pretreatment of ALA, TAC levels were increased significantly and remained constant up to 96 h in vitrified-warmed pre-antral follicles, while ROS levels completely returned to the level of starting point after 96 h of culture in the presence of ALA. Conclusion: Pretreatment of ALA positively influences development of pre-antral follicles in vitrified and non-vitrified samples through increasing follicular TAC level and decreasing ROS levels.

Assessment of vitrification outcome by xenotransplantation of ovarian cortex pieces in γ-irradiated mice: morphological and molecular analyses of apoptosis

PURPOSE

The aim of this study was the investigation of caspase-3/7 activity and apoptosis related gene expression after vitrification and xenotransplantation of human ovarian fragments.

METHODS

Ovarian specimens were obtained from normal female-to-male transsexual women during laparoscopic surgery and cut into small pieces and were considered as vitrified and non-vitrified groups. The morphological study, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, caspase-3/7 activity and apoptosis related gene expression analysis were done in both non-vitrified and vitrified groups in two steps (before transplantation of ovarian tissues and 30 days after transplantation).

RESULT(S)

In spite of high rate of normal follicles in both non-transplanted tissues these rates were significantly decreased in vitrified and non-vitrified grafted tissues, moreover grafted-vitrified tissue showed significantly less normal follicles than grafted-non-vitrified group (P < 0.05). The expression of some pro and anti-apoptotic genes in vitrified-warmed tissues were not changed compared to non-vitrified ones but the expression of Fas and caspase8 was increased and the expression of BRIC5 was decreased in this group (P < 0.05). In transplanted vitrified group the Bcl2, FasL and BRIC5 gene expression was high and caspase8 was low (P < 0.05). The expression of all genes in both grafted groups was more than non-grafted tissues except for caspase8 (P < 0.05). The TUNEL positive signals and caspase-3/7 activity were increased in both grafted groups compared to non-grafted groups and this enzyme activity in grafted-vitrified group was more than grafted-non-vitrified group (P < 0.05).

CONCLUSION(S)

This study provides the first evidence on the significant effect of vitrification on follicular apoptosis of grafted human ovarian tissue at mRNA level. The signs of follicular survival or degeneration detected by morphological assessment and caspase-3/7 activity were closely correlated to the changes in expression of apoptosis-related genes.

Mesenchymal Stem Cells Enhance Angiogenesis and Follicle Survival in Human Cryopreserved Ovarian Cortex Transplantation

Transplantation of cryopreserved ovarian tissue is a novel technique to restore endocrine function and fertility especially for cancer patients. However, the main obstacle of the technique is massive follicle loss as a result of ischemia in the process of transplantation. Mesenchymal stem cells (MSCs) have been acknowledged to play an important role in supporting angiogenesis and stabilizing long-lasting blood vessel networks through release of angiogenic factors and differentiation into pericytes and endothelial cells. This study is aimed to investigate whether MSCs could be applied to overcome the above obstacle to support the ovarian tissue survival in the transplantation. Here we show that human MSCs could enhance the expression level of VEGF, FGF2, and especially the level of angiogenin, significantly stimulate neovascularization, and increase blood perfusion of the grafts in the cryopreserved ovarian tissue transplantation. Further studies reveal that MSCs could notably reduce the apoptotic rates of primordial follicles and decrease follicle loss in the grafted ovarian tissues. In summary, our findings demonstrate a previously unrecognized function of MSCs in improving human ovarian tissue transplantation and provide a useful strategy to optimize fertility preservation and restoration.

Autotransplantation of cryopreserved ovarian tissue--effective method of fertility preservation in cancer patients

OBJECTIVE

To review the literature and to present the latest advances in the autotransplantation of cryopreserved ovarian tissue.

MATERIALS AND METHODS

A literature review was conducted for all relevant articles assessing the fertility preservation, ovarian tissue transplantation, standard freezing and vitrification of ovarian tissue.

RESULTS

One of the promising and effective methods for fertility preservation may be the autotransplantation of cryopreserved ovarian tissue. At present, 30 babies have been born after orthotopic autotransplantation of frozen-thawed human ovarian tissue. Restoration of ovarian activity occurs between 3.5 months and 6.5 months. The longevity of autotransplanted ovarian tissue is about 5-7 years. The follicles are similarly preserved after all freezing methods; however, the ovarian stroma is significantly better preserved after vitrification than after slow freezing. An important topic for further research is preparation of the "vascular bed", optimization of vitrification technique and the development of alternative procedures to avoid the transmission of cancer cells via ovarian tissue autotransplantation - "artificial ovary".

CONCLUSIONS

Cryopreservation of ovarian tissue has unique advantages over other strategies. This method: (1) does not delay cancer treatment; (2) is safer for hormone dependent malignancy; (3) can be done independent of menstrual cycles; (4) is the only option for prepubertal girls; (5) can restore not only fertility but endocrine function.

Oxygen consumption rate of early pre-antral follicles from vitrified human ovarian cortical tissue

The study of human ovarian tissue transplantation and cryopreservation has advanced significantly. Autotransplantation of human pre-antral follicles isolated from cryopreserved cortical tissue is a promising option for the preservation of fertility in young cancer patients. The purpose of the present study was to reveal the effect of vitrification after low-temperature transportation of human pre-antral follicles by using the oxygen consumption rate (OCR). Cortical tissues from 9 ovaries of female-to-male transsexuals were vitrified after transportation (6 or 18 h). The follicles were enzymatically isolated from nonvitrified tissue (group I, 18 h of transportation), vitrified-warmed tissue (group II, 6 and 18 h of transportation) and vitrified-warmed tissue that had been incubated for 24 h (group III, 6 and 18 h of transportation). OCR measurement and the LIVE/DEAD viability assay were performed. Despite the ischemic condition, the isolated pre-antral follicles in group I consumed oxygen, and the mean OCRs increased with developmental stage. Neither the transportation time nor patient age seemed to affect the OCR in this group. Meanwhile, the mean OCR was significantly lower (P < 0.05) in group II but was comparable to that of group I after 24 h of incubation. The integrity of vitrified-warmed primordial and primary follicles was clearly corroborated by the LIVE/DEAD viability assay. These results demonstrate that the OCR can be used to directly estimate the effect of vitrification on the viability of primordial and primary follicles and to select the viable primordial and primary follicles from vitrified-warmed follicles.

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

Background

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

Methods

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

Results

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

Conclusion

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

Effect of therapeutic ultrasound on folliculogenesis, angiogenesis and apoptosis after heterotopic mouse ovarian transplantation

One of the challenges in ovarian transplantation is ischemia-reperfusion damage. When transitional tissue faces an acute and critical condition in terms of blood supply (immediately after organ transplantation), treatment with low-intensity pulsed ultrasound (LIPUS) seems to be very beneficial. The aim of this study was to evaluate the effects of ultrasound therapy on heterotopic transplanted mouse ovarian tissue. Adult female Naval Medical Research Institute mice were divided into three groups. In the experimental groups, the transplanted ovary was exposed 5 min daily to ultrasound with an intensity of 0.3 W/cm(2), frequency of 3 MHz and pulse mode of 1:4. The grafted ovaries were assessed with the usual histology and immunohistochemistry techniques. Results indicate that more CD31 angiogenic factor was expressed in irradiated animals than in control animals, and ultrasound therapy resulted in better follicular preservation, especially after 14 d. In conclusion, therapeutic ultrasound may accelerate and increase re-angiogenesis and can help to promote ovarian follicular growth.

Mathematical model formulation and validation of water and solute transport in whole hamster pancreatic islets

Optimization of cryopreservation protocols for cells and tissues requires accurate models of heat and mass transport. Model selection often depends on the configuration of the tissue. Here, a mathematical and conceptual model of water and solute transport for whole hamster pancreatic islets has been developed and experimentally validated incorporating fundamental biophysical data from previous studies on individual hamster islet cells while retaining whole-islet structural information. It describes coupled transport of water and solutes through the islet by three methods: intracellularly, intercellularly, and in combination. In particular we use domain decomposition techniques to couple a transmembrane flux model with an interstitial mass transfer model. The only significant undetermined variable is the cellular surface area which is in contact with the intercellularly transported solutes, Ais. The model was validated and Ais determined using a 3×3 factorial experimental design blocked for experimental day. Whole islet physical experiments were compared with model predictions at three temperatures, three perfusing solutions, and three islet size groups. A mean of 4.4 islets were compared at each of the 27 experimental conditions and found to correlate with a coefficient of determination of 0.87±0.06 (mean ± SD). Only the treatment variable of perfusing solution was found to be significant (p<0.05). We have devised a model that retains much of the intrinsic geometric configuration of the system, and thus fewer laboratory experiments are needed to determine model parameters and thus to develop new optimized cryopreservation protocols. Additionally, extensions to ovarian follicles and other concentric tissue structures may be made.

Strategies for fertility preservation in young early breast cancer patients

Diagnosis of breast cancer in young women poses a threat to fertility. Due to a recent trend of delaying pregnancy, an increasing number of breast cancer patients in reproductive age wish to bear children. Health care providers have the responsibility to know how to manage fertility issues in cancer survivors. Oncofertility counseling is of great importance to many young women diagnosed with cancer and should be managed in a multi-disciplinary background. Most of young breast cancer patients are candidate to receive chemotherapy, which could lead to premature ovarian failure. A baseline evaluation of ovarian reserve may help in considering the different fertility preservation options. The choice of the suitable strategy depends also on age, type of chemotherapy, partner status and patients' motivation. Various options are available, some established such as embryo and oocyte cryopreservation, some still experimental such as ovarian tissue cryopreservation and ovarian suppression with GnRHa during chemotherapy. An early referral to a reproductive specialist should be offered to patients at risk of infertility who are interested in fertility preservation.

[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.

Production of somatic cell nuclear transfer embryos using in vitro-grown and in vitro-matured oocytes in rabbits

We examined growing oocytes collected from follicles remaining in superovulated rabbit ovaries, that were grown (in vitro growth, IVG) and matured (in vitro maturation, IVM) in vitro. We produced somatic cell nuclear transfer (SCNT) embryos using the mature oocytes and examined whether these embryos have the ability to develop to the blastocyst stage. In addition, we examined the effects of trichostatin A (TSA), a histone deacetylase inhibitor (HDACi), on the developmental competence of SCNT embryos derived from IVG–IVM oocytes. After growth for 7 days and maturation for 14–16 h in vitro, the growing oocytes reached the metaphase II stage (51.4%). After SCNT, these reconstructed embryos reached the blastocyst stage (20%). Furthermore, the rate of development to the blastocyst stage and the number of cells in the blastocysts in SCNT embryos derived from IVG–IVM oocytes were significantly higher for TSA-treated embryos compared with TSA-untreated embryos (40.6 versus 21.4% and 353.1 ± 59.1 versus 202.5 ± 54.6, P < 0.05). These results indicate that rabbit SCNT embryos using IVG–IVM oocytes have the developmental competence to reach the blastocyst stage.

Fertility issues in cancer survivorship

Breakthroughs in cancer diagnosis and treatment have led to dramatic improvements in survival and the need to focus on survivorship issues. Chemotherapy and radiotherapy can be gonadotoxic, resulting in impaired fertility. Techniques to help cancer survivors reproduce have been improving over the past decade. Discussion of the changes to a patient's reproductive health after cancer treatment is essential to providing comprehensive quality care. The purpose of this review is to aid in pre- and posttreatment counseling, focusing on fertility preservation and other strategies that may mitigate risks to the patient's reproductive, sexual, and overall health.

Autotransplantation of cryopreserved ovarian tissue in oncological patients: recovery of ovarian function

ABSTRACT: 

Aim: To present preliminary results of autotransplantation of cryopreserved ovarian tissue performed at Sant’Orsola-Malpighi Hospital, Bologna, Italy. Materials & methods: Orthotopic transplantation was performed in two women with colorectal and breast cancer, and heterotopic transplantation was performed in one Hodgkin’s lymphoma woman. The presence of micrometastasis in the ovarian tissue was checked, and morphological features of ovarian tissue were evaluated before transplantation. Ovarian function was monitored by hormonal and ultrasound-color Doppler examination after transplantation. Results: In all three women, no micrometastasis was found; light and transmission electron microscopy showed well-preserved thawed ovarian tissue. Ovarian function recovery was observed 2–4 months after transplantation. Spontaneous menstrual cycles occurred in two women with normal follicular densities. No periods occurred in the woman with low follicular density at the time of tissue collection. Conclusion: Ovarian tissue cryopreservation and transplantation is a promising approach for preserving ovarian function in women with cancer.

Strategies for fertility preservation in young patients with cancer: a comprehensive approach

As a result of treatment innovations, the survival rates of young people with cancer have increased substantially. The cancers most frequently diagnosed in adults aged 25-49 years include breast, colorectal and cervical cancer and malignant melanoma (Cancer Research UK, 2009). The 5-year survival rates of over 90 % for many malignancies are now reported in young people. But the diagnosis and treatment of cancer often poses a threat to fertility. Methods of fertility preservation are evolving quickly and awareness needs to grow in the medical community regarding these methods. Studies suggest that the ability to have biological children is of great importance to many people. The possible future effects of chemotherapy or radiotherapy on fertility should be discussed with all cancer patients who have reproductive potential. Moreover, fertility preservation should be considered for all young people undergoing potentially gonadotoxic treatment. This article covers the various methods of fertility preserving options in young men and women with respect to the various treatment modalities that they may be subjected to. Sperm banking is a simple and low cost intervention. Embryo cryopreservation is the only established method of female fertility preservation. Oocyte cryopreservation offers a useful option for women without a male partner. Emergency ovarian stimulation and cryopreservation of ovarian tissue (followed by tissue transplantation or in-vitro maturation of oocytes) are experimental techniques for women who require urgent cancer treatment. Large, well-controlled studies are also required to identify any unexpected long-term sequelae of cryopreservation of oocytes and ovarian tissue.

Gene expression in human ovarian tissue after xenografting

Cryobanking and transplantation of ovarian tissue is a promising approach to restore fertility in cancer patients. However, ischemic stress following avascular ovarian cortex grafting is known to induce stromal tissue fibrosis and alterations in follicular development. The aim of the study was to analyze the impact of freeze-thawing and grafting procedures on gene expression in human ovarian tissue. Frozen-thawed ovarian tissue from 14 patients was xenografted for 7 days to nude mice and one ungrafted fragment was used as a control. Immediately after recovery, grafts were processed for RNA extraction and histological analysis. Their expression profile was screened by whole-genome oligonucleotide array (n = 4) and validated by reverse-transcriptase polymerase chain analysis (n = 10). After data filtering, the Limma package was used to build a linear regression model for each gene and to compute its fold change between tissues on Days 0 and 7. After adjusting the P-value by the Sidak method, 84 of the transcripts were significantly altered after 7 days of grafting, including matrix metalloproteinase-9 and -14 and angiogenic factors such as placental growth factor and C-X-C chemokine receptor type 4 (CXCR4). Major biological processes were related to tissue remodeling, including secretory processes, cellular adhesion and response to chemical and hormonal stimuli. Angiopoietin signaling, the interleukin-8 pathway and peroxisome proliferator-activated receptor activation were shown to be differentially regulated. On Day 7, overexpression was confirmed by PCR for interleukin-8, transforming growth factor-beta 1, matrix metalloproteinase-14 and CXCR4, compared with ungrafted controls. In conclusion, new as well as known genes involved in tissue restructuring and angiogenesis were identified and found to play a key role during the first days after human ovarian tissue transplantation. This will facilitate the development of strategies to optimize grafting techniques.

Whole ovine ovaries as a model for human: perfusion with cryoprotectants in vivo and in vitro

These experiments were performed to test the perfusion of ovine as a model for human ovaries by cryoprotectants in vivo at high temperature when the permeability of capillaries is high and when blood is insensibly replaced by the solution of cryoprotectants. By our hypothetical supposition, ovaries could be saturated by cryoprotectants before their surgical removal. The objective was to examine the effectiveness of perfusion of ovine ovaries with vascular pedicle in vivo and in vitro. Arteria ovarica was cannuled and ovaries were perfused by Leibovitz L-15 medium + 100 IU/mL heparin + 5% bovine calf serum + 6% dimethyl sulfoxide + 6% ethylene glycol + 0.15 M sucrose + Indian ink in vivo and in vitro. In the first and second cycle of experiments, ovaries (n = 13 and n = 23) were perfused in vivo and in vitro, respectively, during 60 min with the rate of perfusion 50 mL/h (0.8 mL/min). It was established with in vivo perfusion that only about 10% of ovarian tissues were perfused due to an appearance of multiple anastomoses when the perfusion medium goes from arteria ovarica to arteria uterina without inflow into the ovaries. It was concluded that in vitro perfusion of ovine intact ovaries with vascular pedicle by freezing medium is more effective than this manipulation performed in vivo.

Fertility preservation and minimizing reproductive damage in cancer survivors

Recent advances in oncology have helped in the survival and cure of increasing numbers of childhood cancer patients and those during their reproductive age period. This has increased the need to improve existing technology, and prompted the search for new technologies, to minimize the gonadotoxic effects of cancer treatment and preserve human fertility. Conservative surgical approaches for cancer treatment have been widely accepted following progress in early detection of cancer and accumulating long-term outcome safety data. Gonadal suppression to increase resistance to cancer treatment by gonadotropin analogues and sex hormones has been suggested. However, while this is unlikely to be effective in males, there is no general consensus on its success in the female. Fertility preservation options for both male and female patients include cryopreservation of embryos, gametes and gonads. While embryo cryopreservation is a well-established and successful technique, there are several obvious limitations. Gamete cryopreservation is very successful in males (sperm freezing) while still experimental in females (oocyte freezing), with growing evidence suggesting its potential success. Gonadal cryopreservation is still in its early stages of experimental development, both in males (testicular tissue cryopreservation and in vitro spermatogenesis) and female (ovarian tissue cryopreservation and in vitro follicular maturation).

Basic fibroblast growth factor promotes the development of human ovarian early follicles during growth in vitro

STUDY QUESTION

What is the effect of basic fibroblast growth factor (bFGF) on the growth of individual early human follicles in a three-dimensional (3D) culture system in vitro?

SUMMARY ANSWER

The addition of 200 ng bFGF/ml improves human early follicle growth, survival and viability during growth in vitro.

WHAT IS KNOWN ALREADY

It has been demonstrated that bFGF enhances primordial follicle development in human ovarian tissue culture. However, the growth and survival of individual early follicles in encapsulated 3D culture have not been reported.

STUDY DESIGN, SIZE, DURATION

The maturation in vitro of human ovarian follicles was investigated. Ovarian tissue (n= 11) was obtained from 11 women during laparoscopic surgery for gynecological disease, after obtaining written informed consent. One hundred and fifty-four early follicles were isolated by enzymic digestion and mechanical disruption. They were individually encapsulated into alginate (1% w/v) and randomly assigned to be cultured with 0, 100, 200 or 300 ng bFGF/ml for 8 days.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Individual follicles were cultured in minimum essential medium α (αMEM) supplemented with bFGF. Follicle survival and growth were assessed by microscopy. Follicle viability was evaluated under confocal laser scanning microscope following Calcein-AM and Ethidium homodimer-I (Ca-AM/EthD-I) staining.

MAIN RESULTS AND THE ROLE OF CHANCE

After 8 days in culture, all 154 follicles had increased in size. The diameter and survival rate of the follicles and the percentage with good viability were significantly higher in the group cultured with 200 ng bFGF/ml than in the group without bFGF (P < 0.05). The percentage of follicles in the pre-antral stage was significantly higher in the 200 ng bFGF/ml group than in the group without bFGF (P < 0.05), while the percentages of primordial and primary follicles were significantly lower (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

The study focuses on the effect of bFGF on the development of individual human early follicles in 3D culture in vitro and has limited ability to reveal the specific effect of bFGF at each different stage. The findings highlight the need to improve the acquisition and isolation of human ovarian follicles.

WIDER IMPLICATIONS OF THE FINDINGS

The in vitro 3D culture of human follicles with appropriate dosage of bFGF offers an effective method to investigate their development. Moreover, it allows early follicles to be cultured to an advanced stage and therefore has the potential to become an important source of mature oocytes for assisted reproductive technology; particularly as an option for fertility preservation in women, including patients with cancer.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Basic Research Program of China (2011|CB944504, 2011CB944503) and the National Natural Science Foundation of China (81200470, 81000275, 31230047, 8110197). There are no conflicts of interest to declare.

[Use of conventional assisted reproductive technologies and history of cancer: what are the results?]

Therapeutic advances in oncology have improved the prognosis for long-term survival of children and young adults. As well as other couples or because of adverse side effects of cancer treatments on reproductive function, some cancer survivors will therefore be brought to use assisted reproductive technologies (intrauterine inseminations, in vitro fertilization, intracytoplasmic sperm injection, oocyte or sperm donation…). The purpose of this review is to summarize available scientific datas regarding success rate of assisted reproductive technologies in cancer survivors.

Fertility preservation in women

In women, ∼10% of cancers occur in those <45 years old. Chemotherapy, radiotherapy and bone marrow transplantation can cure >90% of girls and young women with diseases that require such treatments. However, these treatments can result in premature ovarian failure, depending on the follicular reserve, the age of the patient and the type and dose of drugs used. This article discusses the different fertility preservation strategies: medical therapy before chemotherapy; ovarian transposition; embryo cryopreservation; oocyte vitrification; and ovarian tissue cryopreservation. The indications, results and risks of these options are discussed. Whether medical therapy should be used to protect the gonads during chemotherapy remains a source of debate. Fertility preservation needs to be completed before chemotherapy and/or irradiation is started and might take 2-3 weeks with established techniques such as embryo or oocyte cryopreservation. Further studies are needed in patients with cancer to confirm the excellent outcomes obtained in patients without cancer or in egg donation programmes. For prepubertal girls or cases where immediate therapy is required, cryopreservation of ovarian tissue is the only available option. Finally, possible future approaches are reviewed, including in vitro maturation of nonantral follicles, the artificial ovary, oogonial stem cells and drugs to prevent follicle loss.

In vitro development of human primordial follicles to preantral stage after vitrification

PURPOSE

The aim was to culture primordial follicles in vitro to reach preantral stage in vitrified human ovarian tissue.

METHODS

Ovarian tissue samples were obtained from six women. Tissue strips were vitrified by infiltration with a cryoprotectant followed by mounting on a stainless steel carrier. After culturing for 7 days the morphology and developmental stages of follicles enclosed in fresh and vitrified groups were analyzed.

RESULTS

High proportion of viable follicles in vitrified ovarian strips was obtained. After culturing for 7 days the percentage of secondary and preantral follicles increased significantly (P < 0.05) whereas primordial and transitory follicles showed a significant decrease (P < 0.05) compared to their respective counterparts at day 0 of culture.

CONCLUSIONS

Vitrification of ovarian strips with an improved carrier device and culturing of follicles in ovarian strips after warming yielded developed follicles with high viability and morphological integrity that may be suitable for use in fertility preservation among cancer patients.

Is transplantation of cryopreserved ovarian tissue from patients with advanced-stage breast cancer safe? A pilot study

PURPOSE

To assess the safety of reimplantation of cryopreserved ovarian tissue from advanced-stage breast cancer patients.

METHODS

Cryopreserved ovarian cortical fragments were obtained from 13 advanced-stage breast cancer patients aged 17-35 years. After thawing, part of the ovarian cortical tissue was grafted to severe combined immunodeficient mice for 6 months. The presence of malignant mammary cells in ovarian tissue was evaluated after thawing as well as after grafting by 1) histology and immunohistochemistry (epithelial membrane antigen, Her2/neu and gross cystic disease fluid protein 15 identification), and 2) detection of the MGB2 gene by qPCR.

RESULTS

No malignant cells were evidenced by histology and immunohistochemistry. None of the mice died during the 6-month grafting period, nor developed macroscopically visible masses. MGB2 gene expression was detected by qPCR and confirmed by sequencing in frozen-thawed ovarian tissue in 4 cases and in grafts in 1 case.

CONCLUSIONS

This pilot study is the first to evaluate the risk of contamination of cryopreserved ovarian tissue from advanced-stage breast cancer patients by xenotransplantation for 6 months to immunodeficient mice, associated with more conventional screening methods. Our xenografting results are reassuring, but caution needs to be exercised, as MGB2 gene expression was detected in some cases. Larger numbers of ovarian tissue samples from patients with advanced-stage breast cancer are required to confirm our findings before ovarian tissue transplantation can be contemplated in these patients.

Autotransplantation of cryopreserved ovarian tissue in cancer survivors and the risk of reintroducing malignancy: a systematic review

BACKGROUND The risk of recurrent oncological disease due to the reintroduction of cancer cells via autotransplantation of cryopreserved ovarian tissue is unknown. METHODS A systematic review of literature derived from MEDLINE, EMBASE and the Cochrane Library was conducted. Studies on follow-up after autotransplantation; detection of cancer cells in ovarian tissue from oncological patients by histology, polymerase chain reaction or xenotransplantation; and epidemiological data on ovarian metastases were included. RESULTS A total of 289 studies were included. Metastases were repeatedly detected in ovarian tissue obtained for cryopreservation purposes from patients with leukaemia, as well as in one patient with Ewing sarcoma. No metastases were detected in ovarian tissue from lymphoma and breast cancer patients who had their ovarian tissue cryopreserved. Clinical studies indicated that one should be concerned about autotransplantation safety in patients with colorectal, gastric and endometrial cancer. For patients with low-stage cervical carcinoma, clinical data were relatively reassuring, but studies focused on the detection of metastases were scarce. Oncological recurrence has been described in one survivor of cervical cancer and one survivor of breast cancer who had their ovarian tissue autotransplanted, although these recurrences may not be related to the transplantation. CONCLUSIONS It is advisable to refrain from ovarian tissue autotransplantation in survivors of leukaemia. With survivors of all other malignancies, current knowledge regarding the safety of autotransplantation should be discussed. The most reassuring data regarding autotransplantation safety were found for lymphoma patients.

Minimal residual disease detection of leukemic cells in ovarian cortex by eight-color flow cytometry

STUDY QUESTION

How can leukemic cells be detected in cryopreserved ovarian tissue?

SUMMARY ANSWER

Multicolor flow cytometry (FCM) is useful to evaluate the presence of viable leukemic cells in the ovarian cortex with a high specificity and a robust sensitivity.

WHAT IS KNOWN ALREADY

Storing ovarian tissue is an option to preserve fertility before gonadotoxic radiotherapy or chemotherapy treatments. However, transplantation of cryopreserved ovarian cortex to women cured of leukemia is currently not possible due to the risk of cancer re-seeding.

STUDY DESIGN, SIZE, DURATION

We developed an automated ovarian cortex dissociation technique and we used eight-color FCM to identify leukemic cells with a series of dilutions added to ovarian single cell suspensions obtained from healthy cortex.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

Healthy ovarian cortex originated from women between 23 and 39 years of age undergoing laparoscopic ovarian drilling for polycystic ovary syndrome. Blood or bone marrow cells were collected in acute lymphoblastic leukemia (ALL) patients at diagnosis.

MAIN RESULTS AND THE ROLE OF CHANCE

The tissue dissociation technique yield was 1.83 ± 1.49 × 10(6) viable nucleated cells per 100 mg of ovarian cortex. No cell exhibiting a leukemic phenotype was present in the normal ovarian cortex. Added leukemic cells were detected using their leukemia-associated phenotype up to a dilution of 10(-4). When specific gene rearrangements were present, they were detected by real-time quantitative PCR at the same dilution. The ovarian cortex from two leukemia patients was then used, respectively, as positive and negative controls.

LIMITATIONS, REASONS FOR CAUTION

Making available minimal residual disease (MRD) detection techniques (multicolor FCM, PCR and xenograft), that can be used either alone or together, is essential to add a fail-safe oncological dimension to pre-autograft monitoring.

WIDER IMPLICATIONS OF THE FINDINGS

This approach can be performed on fresh ovarian tissue during cryopreservation or on frozen/thawed tissue before reimplantation and it is currently the only available technique in cases of ALL where no molecular markers are identified. This new perspective should lead to studies on ovarian tissue from leukemia patients, for whom the presence of MRD should be established before autograft.

STUDY FUNDINGS/COMPETING INTEREST(S)

The study was supported by the BioMedicine Agency, the Committee of the League against Cancer, the Besançon University Hospital, DGOS/INSERM/INCa and the regional Council of Franche-Comté. There were no conflicts of interest to declare.

The impact of culture conditions on early follicle recruitment and growth from human ovarian cortex biopsies in vitro

OBJECTIVE

To investigate the effects of a dynamic fluidic culture system on early in vitro folliculogenesis in standardized ovarian cortex biopsies.

DESIGN

Cortical small strips were cultured for 6 days in a conventional static or in a dynamic fluidic culture system.

SETTING

University-affiliated laboratory with an associated cryobank facility.

PATIENT(S)

Ovarian cortex from postpuberal female cancer patients (26.1 ± 1.3 y) who opted for cryopreservation of their tissue for fertility protection before gonadotoxic cancer therapy. With informed consent of the Institutional Ethics Committee, part of the tissue was available for patient-related research studies.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The viability and proliferative capacity of the cortex biopsies were evaluated by chemiluminescent microparticle immunoassay for detection of in vitro produced E2 and P in the supernate, by viable follicle counting via calcein staining, by histologic analyses, and by total RNA preparation and reverse transcription for real-time polymerase chain reaction of selected early folliculogenesis genes.

RESULT(S)

The data support the notion that early follicle development can be better achieved in vitro in a dynamic fluidic culture system. The findings are based on the presence of more viable follicles, higher expression levels of early folliculogenesis genes KIT-L, INHB, and GDF9, and the absence of premature luteinization of follicles.

CONCLUSION(S)

This study provides evidence that dynamic fluidic culture is a promising approach for investigating early follicular recruitment and growth in cortical biopsies. It may serve as a first step in a multistep culture system to design a complex in vitro system for complete folliculogenesis.

Developmental potential of human oocytes matured in vitro followed by vitrification and activation

Background

Oocyte in vitro maturation (IVM) and cryopreservation at the time of routine ovarian tissue freezing may be offered to cancer patients as an additional option for fertility preservation. This study aimed to investigate the developmental capacity of oocytes isolated from unstimulated ovaries.

Methods

Immature oocytes (n = 63) from seven consenting premenopausal patients were analysed. Oocytes were collected during routine laparoscopic examination with biopsy of an ovary (cystic adnexal mass, n = 3; cervical adenocarcinoma, n = 2) or oophorectomy (sex reassignment surgery, n = 2) without previous stimulation of the ovaries. The stage of the patient’s menstrual cycle was not considered. Oocytes in all visible antral follicles were aspirated from ovaries, cultured in IVM medium and vitrified at the MII stage before being kept in liquid nitrogen for at least one month. After warming, oocytes were subjected to parthenogenetic activation by chemical stimulus. Their further development was recorded at intervals of 24 hours for up to 6 days of culture.

Results

61.9% of oocytes matured in vitro within 48 hours. The survival rate after vitrification and warming was 61.5%. A total of 75% of surviving oocytes were able to respond to artificial activation, 44.4% of the parthenotes developed to early embryonic stage. However, only 1 in 18 (5.6%) of the resulting embryos reached blastocyst stage.

Conclusions

Oocytes matured in vitro from unstimulated ovaries seem to have limited developmental potential after cryopreservation and artificial activation. Although the outcome of IVM for non-stimulated oocytes is poor, it is currently the only chance besides cryopreservation of ovarian tissue for women for whom ovarian stimulation is not possible due to life circumstances. Based on our preliminary results, we suggest that the use of cryopreserved ovaries for fertility preservation in women with cancer warrants further investigation.

Is vitrification of oocytes useful for fertility preservation for age-related fertility decline and in cancer patients?

The aim of this review is to provide current knowledge on oocyte cryopreservation, with special emphasis on vitrification as a means to preserve fertility in different indications. Major advancements achieved in the past few years in the cryolaboratory have facilitated major changes in our practice. Areas such as fertility preservation for social or oncologic reasons, the possibility to create oocyte banks for egg donation programs, the opportunity to avoid ovarian hyperstimulation syndrome, or to accumulate oocytes in low-yield patients, or even to offer treatment segmentation by stimulating the ovaries, vitrifying, and then transferring in a natural cycle are some of the options that are now available with the development of cryopreservation. We present general experience from our group and others on fertility preservation for age-related fertility decline as well as in oncologic patients, confirming that oocyte vitrification is a standardized, simple, reproducible, and efficient option.

Granulocyte colony-stimulating factor with or without stem cell factor extends time to premature ovarian insufficiency in female mice treated with alkylating chemotherapy

OBJECTIVE

To examine gonadal protective properties of granulocyte colony-stimulating factor (G-CSF) alone or in combination with stem cell factor (SCF) in female mice treated with high-dose alkylating chemotherapy.

DESIGN

Experimental laboratory animal study.

SETTING

Tertiary care academic hospital and research institute.

ANIMAL(S)

Six- and 8-week-old C57Bl/6 female mice.

INTERVENTION(S)

Adult female mice were treated with [1] cyclophosphamide and busulfan (CTx), [2] CTx + G-CSF/SCF, [3] CTx + G-CSF, or [4] normal saline and dimethyl sulfoxide (DMSO; vehicle control).

MAIN OUTCOME MEASURE(S)

Follicle counts, microvessel density, cellular response to DNA damage, and litter production.

RESULT(S)

G-CSF ± SCF increased microvessel density and decreased follicle loss in CTx-treated female mice compared with CTx-only treated female mice. Mice administered CTx alone exhibited premature ovarian insufficiency, with only 28% of mice producing two litters. However, 100% of mice receiving CTx with G-CSF + SCF, and 80% of mice receiving CTx + G-CSF alone produced at least three litters and 20% of mice in each group produced five litters.

CONCLUSION(S)

Treatment of mice with G-CSF decreases chemotherapy-induced ovarian follicle loss and extends time to premature ovarian insufficiency in female mice. Further studies are needed to validate these preclinical results in humans and compare efficacy with the established GnRH analogue treatments.

A review of 15 years of ovarian tissue bank activities

PURPOSE

To review 15 years of activities in ovarian tissue cryobanking from medical database files, including patient indications, histological evaluation and clinical characteristics.

METHODS

Retrospective longitudinal analysis of data from an ovarian tissue bank in an academic hospital. Five hundred and eighty-two patients had their ovarian tissue cryobanked between April 1997 and January 2012. Analysis of cryobanking database: precryopreservation patient characteristics, indications and safety issues, laboratory files and postcryopreservation clinical data.

RESULTS

Of the 582 patients who had their ovarian tissue cryopreserved, 106 patients donated for research purposes and 476 patients for fertility preservation and long-term cryopreservation. Clinical data analysis of the 476 patients revealed a mean age at the time of cryopreservation of 23 ± 8.5 years (range: 9 months - 39 years), with 96.2 % of subjects aged ≤35 years (n = 458). Among 391 cases of malignant disease, hematological malignancies (39.9 %, n = 156) and breast cancer (21.7 %, n = 85) were the two main indications. At histology, malignant cells were found in ovarian tissue from leukemia patients (n = 3) and non-Hodgkin's lymphoma patients (n = 2). Eleven patients underwent autotransplantation, resulting in 5 live births and 1 ongoing pregnancy.

CONCLUSION

This is the largest and most comprehensive study to describe and analyze indications and clinical patient characteristics before and after ovarian tissue cryopreservation. The procedure is safe, easy and promising. The database concept is a useful tool in patient selection for autotransplantation.

Ovarian function is restored after grafting of cryopreserved immature ovary in ewes

As a result of advances in medical treatment, almost 80% of children who are diagnosed with cancer survive long-term. The adverse consequences of cancer treatments include impaired puberty and fertility. In prepubertal girls, the only therapeutic option is the cryopreservation of an ovary. To date, a dozen births have been reported after reimplantation of cryopreserved mature ovaries. To analyze ovarian function after immature grafts, we performed ovarian grafting in a ewe model. Fresh or cryopreserved ovaries from immature ewes were autografted in prepubertal or adult ewes. Cyclic hormonal activity was recovered 3 mo after grafting. Histological analysis demonstrated the presence of all follicle populations and corpora lutea not affected by cryopreservation. After 3 reproductive seasons, births had been observed in all groups, and the follicle-stimulating hormone status was under the limit, which indicated an exhausted ovary. As an indicator of potential imprinting default, the methylation status of the Igf2r gene was analyzed and did not show significant alteration compared with that of nonmanipulated animals. Taken together, these results demonstrate that immature ovarian grafting is able to restore spontaneous puberty and fertility and could guide the reimplantation of immature cortex in women.

Live birth after orthotopic grafting of autologous cryopreserved ovarian tissue and spontaneous conception in Italy

OBJECTIVE

To describe a live birth obtained in Italy after autologous orthotopic transplantation of cryopreserved ovarian cortical tissue.

DESIGN

Case report.

SETTING

University department of gynecology and obstetrics, reproductive medicine and IVF unit.

PATIENT(S)

A 29-year-old patient affected by β-thalassemia (intermedia phenotype) who underwent chemotherapy and bone marrow transplantation at age 21 years, resulting in a complete precocious ovarian failure.

INTERVENTION(S)

Before being treated with chemotherapy (busulfan, cyclophosphamide, and cyclosporine) for bone marrow transplantation, the patient underwent laparoscopic sampling of ovarian cortical tissue that was frozen and cryopreserved in liquid nitrogen. Eight years later, the ovarian tissue was thawed and grafted during laparoscopy at an orthotopic site.

MAIN OUTCOME MEASURE(S)

Ultrasound and endocrine monitoring of the postgrafting restoration of ovarian function; conception, pregnancy, and live birth.

RESULT(S)

Three months after grafting, the decrease of circulating FSH levels and the parallel increase of E(2) levels demonstrated ovarian function restoration, which was confirmed by bidimensional ultrasound and color Doppler examinations. After some ovulatory cycles, the patient spontaneously conceived 16 months after transplantation. After 39 weeks of uneventful gestation, a healthy girl weighing 3,970 g was born.

CONCLUSION(S)

Autologous grafting of cryopreserved ovarian cortex at an orthotopic site may allow ovarian function restoration, spontaneous conception, and birth of a healthy baby.

Case report: stimulation of puberty in a girl with chemo- and radiation therapy induced ovarian failure by transplantation of a small part of her frozen/thawed ovarian tissue

AIM OF THE STUDY

To induce puberty by transplantation of frozen/thawed ovarian tissue collected prior to gonadotoxic treatment for a cancer.

PATIENTS AND METHODS

A 9-year-old girl with Ewing sarcoma had one ovary excised and cryopreserved prior to chemo- and radiotherapy. Functional activity of the remaining ovary was destroyed during treatment. Four and a half years later the girl remained pre-pubertal with postmenopausal levels of FSH. Two of ten pieces of frozen/thawed cortex were transplanted to the remaining ovary in order to stimulate puberty.

RESULTS

Four months after the transplantation FSH returned to low levels. During the following year puberty gradually progressed to Tanner stage B4 and P3 and regular menstrual cycles started. However, after 19 months the function of the graft ceased.

CONCLUSIONS

We have shown for the first time in a girl treated for cancer that transplanted ovarian tissue can regain function and secrete estradiol in a sufficient amount to induce puberty. In addition, the majority of her ovarian tissue remains frozen with a possibility to support fertility in adult life.

Fertility-preserving treatment options in patients with malignant hematological diseases

The number of patients of reproductive age diagnosed with various malignant hematological diseases increases every year. These patients undergo chemotherapy, radiotherapy, and various other treatments that may have gonadotoxic effects. The life expectancy of these patients is increasing rapidly due to the variety of treatment options. As such, an increasing number of patients-as well as their parents and spouses-express their concerns about the patient's fertility post treatment. In the present review it was aimed to provide an overview of current fertility-preserving treatment options and the future of fertility preservation.

Ovarian tissue and follicle transplantation as an option for fertility preservation

OBJECTIVE

To review and summarize data from the scientific literature on ovarian tissue and follicle transplantation as an option for fertility preservation.

DESIGN

Review of pertinent literature.

SETTING

University hospital.

PATIENT(S)

Women having undergone ovarian tissue transplantation.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Review of the literature.

RESULT(S)

Over the last decade, the field of ovarian transplantation and cryopreservation has significantly progressed, becoming applicable in humans. Indeed, fresh and frozen cortical ovarian tissue transplantations have been successfully reported worldwide, resulting in around 28 healthy babies. Although ovarian-tissue harvesting seems to be safe, the risk of reimplantation of cancer from ovarian cortical transplants cannot be estimated at this time. As a consequence, auto-transplantation of ovarian tissue in women having suffered from systemic hematological malignancies is not recommended. In these situations, reimplantation of isolated ovarian follicles might represent an interesting option in the future.

CONCLUSION(S)

Although the clinical experience is limited, the robust results obtained open new perspectives for the management of premature ovarian failure resulting or not from gonadotoxic treatments.