Laparoscopic ovariectomy for whole human ovary cryopreservation: technical aspects

Fertility-enhancing effects of inositol & vitamin C on cisplatin induced ovarian and uterine toxicity in rats via suppressing oxidative stress and apoptosis

Cisplatin can lead to infertility due to its negative impact on the uterus and ovaries. This study aimed to explore the effects of Inositol and vitamin C on cisplatin-induced infertility. Forty-eight adult female Wistar rats were divided into eight groups (N = 6) and orally treated for 21 days. The treatments were as follows: negative control (saline), positive control (saline and cisplatin injected into the abdomen on day 15), T1-T3: rats given vitamin C (150 mg/kg), Inositol (420 mg/kg), and vitamin C + Inositol, respectively, along with cisplatin injected into the abdomen on day 15, T4-T6: rats given only vitamin C, Inositol, and vitamin C + Inositol, respectively. Vitamin C and Inositol enhanced cisplatin-induced histopathological improvements in the uterus and ovaries, raising progesterone and estradiol serum levels. Furthermore, the supplements enhanced ESR1 gene expression in the uterus and ovary, reducing uterine and ovarian apoptosis caused by cisplatin through modulation of caspase 3, 8, and Bcl-2 gene levels. These substances decreased ovarian and uterine malondialdehyde levels, boosted total antioxidant capacity and superoxide dismutase, and alleviated oxidative stress. The findings reveal that vitamin C and Inositol shield against cisplatin-related infertility by reducing oxidative stress and apoptosis in the uterus and ovaries.

Fertility Preservation in Women with Endometriosis

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

Transplantation of Refrozen Ovarian Cortical Strips Retrieved from a Cryopreserved Whole Ovary: Proof of Feasibility

We report successful clinical outcomes after transplantation of refrozen-rethawed cortical strips from a cryopreserved whole ovary in a patient diagnosed with stage IIIb rectal adenocarcinoma. Whole ovary cryopreservation was proposed as a fertility preservation strategy in 2006 prior to radiotherapy, chemotherapy and oncological surgery. To allow for minimal residual disease screening before ovarian reimplantation, the whole ovary was thawed and dissected into cortical strips. While awaiting the results, the majority of the cortical strips were refrozen. These refrozen-rethawed cortical strips were laparoscopically grafted to 2 sites: the previously irradiated pelvic cavity and the non-irradiated extrapelvic cavity. Ovarian function resumption was assessed by recovery of menses, hormone levels, ultrasound and oocyte pick-up following controlled ovarian stimulation (COS). Restoration of ovarian function occurred 6 months after reimplantation, with recovery of menses and estradiol secretion. A total of 12 cycles were followed by the IVF department. A second reimplantation was performed 1.5 years later, since the grafts were found to have stopped functioning for >3 consecutive months. Overall, 3 fertilizable oocytes were retrieved transabdominally from the extrapelvic graft following COS, yielding 2 embryos and culminating in one fresh embryo transfer, but no pregnancy. Concerning the reimplantation site, no ovarian activity was detected in the graft placed in the previously irradiated pelvic cavity. Indeed, only fibrotic-looking tissue was observed in the pelvic site at second laparoscopy 1.5 years later, while ovarian activity was noted in the extrapelvic graft, showing a large antral follicle. All in all, transplantation of refrozen-rethawed cortical strips from a cryopreserved whole ovary can lead to ovarian function resumption and embryo development if grafted to a non-irradiated field.

Two-Decade Experience of Royan Institute in Obtaining Mature Oocyte from Cryopreserved Ovarian Tissue: In Vitro and In Vivo Approaches

Ovarian tissue cryopreservation (OTC) holds promise for preservation of fertility among women who have lost their fertility due to diseases such as cancer. OTC has significantly assisted such cases by helping them maintain normal hormonal levels and menstrual cycles. Appropriate strategies to develop and extract mature oocytes from OTC could overcome a range of complications that are associated with ovarian dysfunction, caused by aging, and primary or secondary ovarian insufficiency. Scientists from different departments at The Royan Institute (Tehran, Iran) have been conducting studies to find the best way to extract mature oocytes from animal and human cryopreserved ovarian tissues. The various studies conducted in this area in the past 20 years, by researchers of the Royan Institute, are collated and provided in this review, in order to provide an idea of where we are now in the area of fertility preservation.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Whole Ovary Cryopreservation and Transplantation: A Systematic Review of Challenges and Research Developments in Animal Experiments and Humans

Ovarian tissue cryopreservation and transplantation is the only fertility preservation option that enables both restoration of fertility and resumption of ovarian endocrine function, avoiding the morbidity associated with premature menopause. It is also the only technique available to prepubertal patients and those whose treatment cannot be delayed for life-threatening reasons. Ovarian tissue cryopreservation can be carried out in two different ways, either as ovarian cortical fragments or as a whole organ with its vascular pedicle. Although use of cortical strips is the only procedure that has been approved by the American Society for Reproductive Medicine, it is fraught with drawbacks, the major one being serious follicle loss occurring after avascular transplantation due to prolonged warm ischemia. Whole ovary cryopreservation involves vascular transplantation, which could theoretically counteract the latter phenomenon and markedly improve follicle survival. In theory, this technique should maintain endocrine and reproductive functions much longer than grafting of ovarian cortical fragments. However, this procedure includes a number of critical steps related to (A) the level of surgical expertise required to accomplish retrieval of a whole ovary with its vascular pedicle, (B) the choice of cryopreservation technique for freezing of the intact organ, and (C) successful execution of functional vascular reanastomosis upon thawing. The aim of this systematic review is to shed light on these challenges and summarize solutions that have been proposed so far in animal experiments and humans in the field of whole ovary cryopreservation and transplantation.

Engineered reproductive tissues

Engineered male and female biomimetic reproductive tissues are being developed as autonomous in vitro units or as integrated multi-organ in vitro systems to support germ cell and embryo function, and to display characteristic endocrine phenotypic patterns, such as the 28-day human ovulatory cycle. In this Review, we summarize how engineered reproductive tissues facilitate research in reproductive biology, and overview strategies for making engineered reproductive tissues that might eventually allow the restoration of reproductive capacity in patients.

Ovarian tissue vitrification is more efficient than slow freezing to preserve ovarian stem cells in CF-1 mice

OBJECTIVE

The aim of this study was to investigate the efficacy of protocols for mice ovary cryopreservation to compare the differences in Mouse Vasa Homologue expression (a germline cell marker) and ovarian viability after vitrification or slow freezing.

METHODS

Female CF1 mice aged 40-45 days were randomly divided into three groups: Control, vitrification or slow freezing. Their ovaries were surgically removed, rinsed in saline solution and cryopreserved. For vitrification, we used a commercial protocol and for slow freeze, we used 1.5 M ethylene glycol (EG) as cryoprotectant. After that, the ovaries were processed for histological an immunohistochemical analysis, and counting of primordial, primary, pre-antral and antral follicles.

RESULTS

No significant difference was found in the proportion of high-quality primordial, primary and pre-antral follicles after thawing/warming in the slow freezing and vitrification groups. The immunohistochemistry for MVH antibody demonstrated that the slow freeze group had a higher number of unmarked cells (p=0.012), indicating a harmful effect on the MVH expression in the ovarian tissue, where the cell structure is complex.

CONCLUSION

Although both protocols indicated similar results in the histological analysis of follicular counts, the vitrification protocol was significantly better to preserve ovarian stem cells, an immature germ cell population. These cells are able to self-renew having regeneration potential, and may be effective for the treatment of ovarian failure and consequently infertility.

Preserving fertility in female patients with hematological malignancies: a multidisciplinary oncofertility approach

Oncofertility is a new interdisciplinary field at the intersection of oncology and reproductive medicine that expands fertility options for young cancer patients. The most common forms of hematological malignancies that occur in girls and young women and therefore necessitate oncofertility care are acute lymphocytic leukemia, acute myeloid leukemia, non-Hodgkin's lymphoma, and Hodgkin's lymphoma. Aggressive gonadotoxic anticancer regimens including alkylating chemotherapy and total body irradiation are used often in treating girls and young women with hematological malignancies. The risks of gonadotoxicity and subsequent iatrogenic premature ovarian insufficiency and fertility loss depend mainly on the type and stage of the disease, dose of anticancer therapy as well as the age of the patient at the beginning of treatment. To avoid or at least mitigate the devastating complications of anticancer therapy-induced gonadotoxicity, effective and comprehensive strategies that integrate different options for preserving and restoring fertility ranging from established to experimental strategies should be offered before, during, and after chemotherapy or radiotherapy. A multidisciplinary approach that involves strong coordination and collaboration between hemato-oncologists, gynecologists, reproductive biologists, research scientists, and patient navigators is essential to guarantee high standard of care.

Dose dependent effect of resveratrol in preventing cisplatin-induced ovarian damage in rats: An experimental study

This study aimed to evaluate the effect of resveratrol in preventing cisplatin (CP) induced ovarian damage in rats. Twenty-eight female Wistar albino rats were separated into four groups. No medication was given to group 1. Over the 21-day study period, low-dose resveratrol was given to group 2, high-dose resveratrol was given to group 3, and saline was administered to group 4. On the 15th day of medication, all groups except for group 1 were treated with a single dose of CP. Serum levels of anti-Mullerian hormone (AMH) were tested at baseline and on the 15th and 21st days. All rats underwent oophorectomy one week after CP application. Primordial, primary, secondary, and tertiary follicles were counted microscopically. No significant difference was observed among the groups in mean AMH levels according to follow-up time. The numbers of primary and primordial follicles were statistically significantly higher in group 2 than in group 4 (p<0.05). The number of tertiary follicles was statistically significantly higher in group 1 than in groups 3 and 4 (p<0.05), but it was not statistically significantly different than in group 2. Resveratrol, particularly at low-doses, can prevent CP induced ovarian damage by maintaining the numbers of primordial and primary follicles. Further studies are needed to study the effect of resveratrol on human ovaries.

A review of reported surgical techniques in fertility preservation for prepubertal and adolescent females facing a fertility threatening diagnosis or treatment

BACKGROUND

Ovarian tissue cryopreservation is increasing as a preferred option for fertility preservation for prepubertal and young adolescent females facing a fertility threatening diagnosis or treatment.

DATA SOURCES

Ovid MEDLINE and PubMed searches for terms related to ovarian tissue removal for fertility preservation revealed there is no current consensus on operative technique for surgical ovarian cortical tissue removal in adult females. Additionally, there are limited published reports of surgical approach and outcomes in the pediatric population. In total, 22 publications were reviewed for their operative approach, ovarian tissue harvesting techniques, complications and outcomes.

CONCLUSIONS

Reported operative approaches and techniques for ovarian tissue cryopreservation for pediatric and adolescent patients are variable. Further investigations into operative technique and tissue harvesting that maintains healthy ovarian follicles for transplant will help establish standard technical principles for surgery in pediatric and adolescent females undergoing fertility preservation.

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

PURPOSE

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

METHODS

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

RESULTS

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

New advances in ovarian autotransplantation to restore fertility in cancer patients

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

VEGF and FGF2 Improve Revascularization, Survival, and Oocyte Quality of Cryopreserved, Subcutaneously-Transplanted Mouse Ovarian Tissues

This study was conducted to investigate the effect of the vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2) on revascularization, survival, and oocyte quality of cryopreserved, subcutaneously-transplanted mouse ovarian tissue. Autologous subcutaneous transplantation of vitrified-thawed mouse ovarian tissues treated with (experimental group) or without (control group) VEGF and FGF2 was performed. After transplantation to the inguinal region for two or three weeks, graft survival, angiogenesis, follicle development, and oocyte quality were examined after gonadotropin administration. VEGF coupled with FGF2 (VEGF/FGF2) promoted revascularization and significantly increased the survival rate of subcutaneously-transplanted cryopreserved ovarian tissues compared with untreated controls. The two growth factors did not show long-term effects on the ovarian grafts. In contrast to the untreated ovarian grafts, active folliculogenesis was revealed as the number of follicles at various stages and of mature oocytes in antral follicles after gonadotropin administration were remarkably higher in the VEGF/FGF2-treated groups. Although the fertilization rate was similar between the VEGF/FGF2 and control groups, the oocyte quality was much better in the VEGF/FGF2-treated grafts as demonstrated by the higher ratio of blastocyst development. Introducing angiogenic factors, such as VEGF and FGF2, may be a promising strategy to improve revascularization, survival, and oocyte quality of cryopreserved, subcutaneously-transplanted mouse ovarian tissue.

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

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

Updates in preserving reproductive potential of prepubertal girls with cancer: Systematic review

INTRODUCTION

With increasing numbers of adult female survivors of childhood cancers due to advances in early diagnosis and treatment, the issue of preserving the reproductive potential of prepubertal girls undergoing gonadotoxic treatments has gained greater attention.

METHODS

According to PRISMA guidelines, a systematic review of the literature was performed for all relevant full-text articles published in PubMed in English throughout the past 15 years to explore the significant updates in preserving the reproductive potential of prepubertal girls with cancer.

RESULTS

The two established fertility preservation options, embryo freezing and egg freezing, cannot be offered routinely to prepubertal girls as these options necessitate prior ovarian stimulation and subsequent mature oocytes retrieval that are contraindicated or infeasible before puberty. Therefore, the most suitable fertility preservation options to prepubertal girls are (1) ovarian tissue freezing and autotransplantation, (2) in vitro maturation, and (3) ovarian protection techniques. In this review, we discuss in detail those options as well as their success rates, advantages, disadvantages and future directions. We also suggest a new integrated strategy to preserve the reproductive potential of prepubertal girls with cancer.

CONCLUSION

Although experimental, ovarian tissue slow freezing and orthotopic autotransplantation may be the most feasible option to preserve the reproductive potential of prepubertal girls with cancer. However, this technique has two major and serious disadvantages: (1) the risk of reintroducing malignant cells, and (2) the relatively short lifespan of ovarian tissue transplants. Several medical and ethical considerations should be taken into account before applying this technique to prepubertal girls with cancer.

Ovarian tissue freezing: current status

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Restoration of ovarian function and natural fertility following the cryopreservation and autotransplantation of whole adult sheep ovaries

STUDY QUESTION

Is it possible to restore ovarian function and natural fertility following the cryopreservation and autotransplantation of whole ovaries, complete with vascular pedicle, in adult females from a large monovulatory animal model species (i.e. sheep)?

SUMMARY ANSWER

Full (100%) restoration of acute ovarian function and high rates of natural fertility (pregnancy rate 64%; live birth rate 29%), with multiple live births, were obtained following whole ovary cryopreservation and autotransplantation (WOCP&TP) of adult sheep ovaries utilizing optimized cryopreservation and post-operative anti-coagulant regimes.

WHAT IS KNOWN ALREADY

Fertility preservation by WOCP&TP requires successful cryopreservation of both the ovary and its vascular supply. Previous work has indicated detrimental effects of WOCP&TP on the ovarian follicle population. Recent experiments suggest that these deleterious effects can be attributed to an acute loss of vascular patency due to clot formation induced by damage to ovarian arterial endothelial cells.

STUDY DESIGN, SIZE, DURATION

Study 1 (2010–2011; N = 16) examined the effect of post-thaw perfusion of survival factors (angiogenic, antioxidant, anti-apoptotic; n = 7–8) and treatment with aspirin (pre-operative versus pre- and post-operative (n = 7–9)) on the restoration of ovarian function for 3 months after WOCP&TP. Study 2 (2011–2012; N = 16) examined the effect of cryoprotectant (CPA) perfusion time (10 versus 60 min; n = 16) and pre- and post-operative treatment with aspirin in combination with enoxaparine (Clexane^®; n = 8) or eptifibatide (Integrilin^®; n = 8) on ovarian function and fertility 11–23 months after WOCP&TP.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Both studies utilized mature, parous, Greyface ewes aged 3–6 years and weighing 50–75 kg. Restoration of ovarian function was monitored by bi-weekly blood sampling and display of behavioural oestrus. Blood samples were assayed for gonadotrophins, progesterone, anti-Müllerian Hormone and inhibin A. Fertility restoration in Study 2 was quantified by pregnancy rate after a 3 month fertile mating period and was confirmed by ultrasound, hormonal monitoring and live birth. Ovarian function was assessed at sacrifice by ovarian appearance and vascular patency (Doppler ultrasound) and by follicular histology.

MAIN RESULTS AND THE ROLE OF CHANCE

In Study 1, survival factors were found to have no benefit, but the inclusion of pre-operative aspirin resulted in four ewes showing acute restoration of ovarian function within 3 weeks and a further six ewes showing partial restoration. The addition of post-operative aspirin alone had no clear benefit. In Study 2, combination of aspirin with additional post-operative anti-coagulants resulted in total acute restoration of ovarian function in 14/14 ewes within 3 weeks of WOCP&TP, with 9/14 ewes becoming pregnant and 4/14 giving birth to a total of seven normal lambs. There was no difference between anti-coagulants in terms of restoration of reproductive function and fertility. In contrast, the duration of CPA perfusion was highly significant with a 60 min perfusion resulting in ovaries of normal appearance and function with high rates of primordial follicle survival (70%) and an abundant blood supply, whereas ovaries perfused for 10 min had either resorbed completely and were vestigial (7/14) or were markedly smaller (P < 0.01). It is concluded that both the degree of CPA penetration and the maintenance of post-operative vascular patency are critical determinants of the success of WOCP&TP.

LIMITATIONS, REASONS FOR CAUTION

Before application of this technology to fertility preservation patients, it will be critical to optimize the CPA perfusion time for different sized human ovaries, determine the optimum period and level of anti-coagulant therapy, and confirm the normality of offspring derived from this procedure.

WIDER IMPLICATIONS OF THE FINDINGS

This technology holds promise for the preservation of fertility in women. It could also potentially be applied to the cryopreservation of other reproductive or even major organs (kidneys) where there are considerable difficulties in storing donated tissue.

STUDY FUNDING/COMPETING INTEREST(S)

Funding was received from the Medical Research Council, University of Nottingham. The authors confirm that they have no conflict of interest in relation to this work.

Ovarian tissue cryopreservation: a committee opinion

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

[Ovarian cryopreservation: evaluation of two surgical procedures]

OBJECTIVES

To evaluate various surgical techniques for partial oophorectomy cryopreservation. To evaluate the consequences of prior exposure to cytotoxic therapy on the quality of the ovary removed.

PATIENTS AND METHODS

Single center retrospective observational study over 4 years of women who had ovarian cryopreservation surgery for chemotherapy or radiotherapy which were at high risk of premature ovarian failure. Several techniques have been proposed: partial oophorectomy with clamping of the vascular gonadal pedicle (indirect tissue sample) without clamping (direct tissue sample) and partial oophorectomy with an automatic stapler. Ovarian tissue was immediately prepared for cryopreservation in the operating theatre. The whole sample was divided into small slices. For each ovary, a count of small slices was made. Additionally, one slice was examined to determine the presence of primordial follicles.

RESULTS

Ovary was successfully removed and cryopreserved in 13 patients. Two bleeding events occurred with the direct technique, without consequences for patients. The number of fragments obtained between indirect and direct techniques was respectively 19 vs 15, P=0.18; the number of primordial follicles was 38 vs 36, P=0.87. The automatic stapler consumed too much ovarian tissue to be interesting. There were fewer fragments, 15 vs 20, P<0.05 and primordial follicles, 35 vs 40, P=0.65, after a first cycle of chemotherapy.

DISCUSSION AND CONCLUSION

The vascular clamping technique is safer but with no difference in the quality of the sample tissue. One cycle of chemotherapy has a pejorative impact on the quality of the sample tissue.

Fertility preservation in gynecological cancers

For cancers of reproductive system in women, fertility preservation is complex. Fertility is also affected by therapies, however prevention is possible. Radiotherapy affects gonads, uterus, and subsequent pregnancy outcomes in all ages. However, degree and damage depend on dose, irradiation field, and age at the time of exposure. Ovarian transposition is considered if ovarian involvement is unlikely. Gonadotoxic effects of chemotherapy are related to agent's type, cumulative doses, age, and ovarian reserve. Some agents are highly toxic. Rendering follicular development quiescent by suppression of gonadotropins does reduce the ovarian damage. Simple or radical trachelectomy can be used in early cervical cancer. Fertility saving surgery is possible only in early stage low grade epithelial cancers of the ovary, however, in germ cell tumors even in advanced stages it may be possible to preserve fertility. There are no standard recommendations for endometrial cancer. Embryo, oocyte, and ovarian tissue cryopreservation are possible. The human embryo is very resistant to damage. In view of these possibilities, it is advocated that attention to long term health and quality of life in gonadotoxic therapy must be incorporated into plans as early as possible.

Viability of human ovarian tissue confirmed 5 years after freezing with spontaneous ice-formation by autografting and chorio-allantoic membrane culture

To achieve optimal and uniform outcomes, slow cooling protocols for human ovarian tissues generally initiate ice formation at high sub-zero temperatures (-6 to -9 °C). The aim of the study was to investigate the function of ovarian tissue that had unintentionally self seeded at -20 °C during the freezing step, by examining its development following chicken embryonic chorioallantoic membrane (CAM) grafting and after transplantation back to the patient. Ovarian tissue was frozen in 6% (v/v) dimethyl sulfoxide, 6% (v/v) ethylene glycol and 0.15M sucrose which had self-seeded at -20 °C. Five years after cryopreservation, 8 pieces were thawed and transplanted back to the patient. Two small (1 × 2 × 1 mm) pieces of this thawed tissue were cultured in a CAM-system for 5 days to assess the tissue viability. The autografted ovarian tissue re-established spontaneous menstrual bleeding within five months and raised serum 17-β Estradiol from 19 to 330 pg/ml. Ultrasound revealed a dominant follicle at the site of the transplanted tissue in the follicular phase after the menstrual bleed. Analysis of the CAM cultured tissue established that 88% of the primordial follicles are degenerated and there was limited in growth of blood vessels. In conclusion, in spite of the damage caused by the cryopreservation with spontaneous ice-formation the viability could be confirmed by CAM culture and the restoration of ovarian function after auto-transplantation.

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.

Fertility Preservation Methods in Breast Cancer

Thanks to the recent advances in reproductive medicine, more and more young women with breast cancer may be offered the possibility of preserving their fertility. Fertility can be endangered by chemotherapy, by treatment duration and by patient's age at diagnosis. The currently available means to preserve a young woman's fertility are pharmacological protection with gonadotrophin-releasing hormone analogues during chemotherapy, and ovarian tissue or oocyte/embryo freezing before treatment. New future venues, including in vitro maturation, will improve the feasibility and efficacy of the fertility preservation methods in breast cancer patients.

Viability and function of the cryopreserved whole rat ovary: comparison between slow-freezing and vitrification

OBJECTIVE

To investigate four different protocols for cryopreservation of the whole rat ovary with intact vasculature to evaluate whether differences exist in post-thawing viability of the ovary after either vitrification or slow freezing.

DESIGN

Experimental study.

SETTING

Obstetrics and gynecology department.

ANIMAL(S)

Immature Sprague-Dawley female rats.

INTERVENTION(S)

Ovaries were isolated with the vascular tree intact up to the bifurcation of the abdominal aorta and were subsequently cannulated. The ovaries were flushed with increasing concentrations of the cryoprotectant dimethyl sulfoxide (DMSO) to either 1.5 or 7 M. The ovaries underwent cryopreservation by vitrification or passive slow freezing.

MAIN OUTCOME MEASURE(S)

After thawing, the ovaries were subjected to neutral red viability staining to assess the density of viable small follicles and for long-term (48 hours) incubation evaluation of steroid secretion, histology, and apoptosis assay.

RESULT(S)

The follicular viability was decreased in both vitrification groups and in the slow-freezing group with the high concentration of DMSO, as compared with fresh controls. Estradiol levels in the incubation medium followed the same pattern. Light microscopy revealed well-preserved morphology in all groups after 48 hours' incubation. Apoptosis was increased in both vitrified and cryopreserved ovaries.

CONCLUSION(S)

We have developed a new method that can be used in basic studies to improve cryopreservation protocols. Our initial findings suggest that a moderate concentration of the cryoprotectant DMSO is superior to a high DMSO concentration for both vitrification and slow freezing.

Fertility preservation in girls

Children that undergo treatment for cancer are at risk of suffering from subfertility or hormonal dysfunction due to the detrimental effects of radiotherapy and chemotherapeutic agents on the gonads. Cryopreservation of ovarian tissue prior to treatment offers the possibility of restoring gonadal function after resumption of therapy. Effective counseling and management of pediatric patients is crucial for preserving their future reproductive potential. The purpose of this article is to review recent literature and to revise recommendations we made in a 2007 article. Pediatric hemato-oncology, reproductive endocrinology, surgery, anesthesia and bioethics perspectives are discussed and integrated to propose guidelines for offering ovarian cryopreservation to premenarcheal girls with cancer.

Which are the ideal donor and recipient vessels for a whole ovarian transplantation?

OBJECTIVE

To compare deep circumflex iliac (DCI) and deep inferior epigastric (DIE) pedicles as potential recipient vessels for a whole ovarian microvascular transplantation.

DESIGN

Anatomical study.

SETTING

Laboratory of anatomy, university center.

PATIENT(S)

Ten fresh human female cadavers.

INTERVENTION(S)

Anatomical dissections, vascular injections, histologic analysis.

MAIN OUTCOME MEASURE(S)

Morphological analysis of the gonadic, DCI, and DIE pedicles; diameter of the vessels at regular intervals along their entire length. Comparisons of the caliber values between receiving (DCI and DIE) and gonadic pedicles aiming to determine the optimal size match.

RESULT(S)

We highlight a tortuous appearance of the gonadic artery. This morphology contrasted with the venous system that included two or three straight veins, one of them being wider than the others. The gonadic vessels converge into a wider artery and vein at 5 cm from the ovary. An optimal size match existed between gonadic and DCI arteries and veins sections, in 13 of 14 gonadic pedicles.

CONCLUSION(S)

A safe microsurgical whole ovarian transplantation is feasible if the gonadic pedicle is harvested with a minimal length of 5 cm from the ovary. The DCI pedicle seems to have the best size match with the ovarian vessels to perform a reliable end-to-end microvascular anastomosis.

The human postmenopausal ovary as a tool for evaluation of cryopreservation protocols towards whole ovary cryopreservation

PURPOSE

Cryopreservation of a complete ovary may be a future method for fertility preservation in cancer patients. Difficulties exist in cryopreservation of the relatively large ovarian tissue mass. This study evaluates whether a human postmenopausal ovary can be used, as a complement to animal models, in studies of this research field.

METHODS

Postmenopausal human ovaries (n = 10) were isolated and flushed through ovarian arteries with either the cryoprotectant dimethylsulphoxide or Ringer-Acetate, followed by slow freezing. After thawing, production of androgens during in vitro perfusion and morphology (light/electron microscopy) were assessed.

RESULTS

The dimethylsulphoxide-cryopreserved ovaries showed larger secretion of androgens during perfusion than Ringer Acetate-cryopreserved ovaries. Light microscopy showed well preserved morphology in both groups. Electron microscopy revealed normal appearance of stroma and vessels in the dimethylsulphoxide group.

CONCLUSIONS

The study demonstrates the potential to use the postmenopausal human ovary for further studies aiming at optimizing cryopreservation protocols, with special reference to ovarian vascularity and stroma.

Orthotopic and heterotopic ovarian tissue transplantation

Although still experimental, cryopreservation and transplantation techniques for ovarian tissue have been well described, and a number of successful human pregnancies have occurred. Ovarian cryopreservation is the only fertility preservation procedure that can be offered to prepubertal children, and when cytotoxic treatment is urgent. There are two main approaches for autotransplantation of human ovarian tissue. In the heterotopic transplantation, cortical fragments can be grafted subcutaneously at various sites whereas in orthotopic transplantation cortical pieces are transplanted into its original location. Both approaches have their own advantages and disadvantages. While natural pregnancy can occur in orthotopic transplantation, heterotopic transplantation may be indicated if the pelvis is not suitable for transplantation due to previous radiation or severe scar formation. Furthermore, tissue monitoring may be easier in the heterotopic site. In this article, we reviewed the indications, limitations, risks and transplantation techniques for ovarian tissue.

Abnormally low expression of connexin 37 and connexin 43 in subcutaneously transplanted cryopreserved mouse ovarian tissue

PURPOSE

To analyze the gap junction proteins connexin 37 (Cx37) and connexin 43 (Cx43) after subcutaneous transplantation of cryopreserved mouse ovarian tissue.

METHODS

Expression of gap junction genes was assessed by immunohistochemistry and real-time polymerase chain reaction (PCR) in transplanted cryopreserved ovarian tissue compared with that of normal ovarian tissue. Apoptosis of ovarian cells was evaluated by using the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphates nick end-labeling method.

RESULTS

After subcutaneous transplantation, Cx37 and Cx43 mRNA and protein expression were significantly lower in cryopreserved than in normal ovarian tissue. Apoptosis was increased in granulosa cells from antral follicles of the cryopreserved tissue.

CONCLUSION

After cryopreservation and subcutaneous transplantation of ovarian tissue, proteins forming gap junctions between oocytes and granulosa cells are under-expressed compared with normal controls.

Preservation of fertility in young cancer patients: contribution of transmission electron microscopy

During the last decade, new technologies in reproductive medicine have emerged to preserve the fertility of women whose gonadal function is threatened by premature menopause or gonadotoxic treatments. To offer an individualized approach to these patients, different experimental procedures are under investigation, including oocyte cryopreservation and cryopreservation and transplantation of ovarian tissue in the form of cortical fragments, whole ovary or isolated follicles. This review shows that transmission electron microscopy (TEM), combined with other in-vivo and in-vitro analysis techniques, is a valuable tool in the establishment of new experimental protocols to preserve female fertility. Ultrastructural studies allow in-depth evaluation of the oocyte's unique morpho-functional characteristics, which explain its low cryotolerance, and provide essential information on follicular, stromal and endothelial cell integrity, as well as cellular interactions crucial for normal folliculogenesis. In order to be able to offer appropriate and efficient options in every clinical situation, oocyte in-vitro maturation and ovarian tissue transplantation need to be optimized. Further development of new approaches, such as follicular isolation and whole ovary transplantation, should be encouraged. Fine ultrastructural details highlighted by TEM studies will be useful for the further optimization of these emerging technologies.

Reproductive outcome after transplantation of ovarian tissue: a systematic review

BACKGROUND

Despite interest in ovarian tissue transplantation (OTT) as a promising procedure for fertility preservation, to date, no precise data are available about its effectiveness. We systematically reviewed reproductive function after OTT for fertility preservation in women at high risk of premature ovarian failure (POF).

METHODS

We searched the MEDLINE, EMBASE, Cochrane Systematic Reviews, CENTRAL, Web of Science and Scopus databases for studies on the reproductive outcomes after OTT in humans up to June 2007. Women with follicle-stimulating hormone (FSH) >30 IU/l at the time of OTT were included in a meta-analysis of individual-patient data to evaluate the time to re-establishment of ovarian function (ROF). Secondary outcomes included short-term (<12 months) and long-term (>12 months) ovarian function (OVF) and pregnancy after OTT.

RESULTS

We identified 25 reports including 46 unique cases. OTT was performed to treat POF in 27 women, to prevent POF in 15, to treat infertility in 2 and accidentally in 1. In 23 women with FSH >30 at the time of OTT, OVF was re-established with a median time to ROF of 120 days (range 60-244). Within 6 months after ROF, four women had recurrent ovarian failure. There are insufficient data to evaluate the long-term OVF (>12 months). Fresh grafts had an increased likelihood of return of OVF and a decreased likelihood for recurrent ovarian failure compared with cryopreserved grafts [HR of 2.44 (95% CI 0.92, 6.49) and 0.47 (95% CI 0.18, 1.12), respectively]. In 25 women who sought pregnancy, eight women had nine pregnancies at 12 months, giving a cumulative pregnancy rate of 37% (95% CI 19, 60).

CONCLUSIONS

Transplantation of ovarian tissue can re-establish OVF after POF; however, the efficacy of OTT using cryopreserved tissues is not yet equivalent to that of fresh grafts. A controlled multicenter trial with sufficient follow-up would provide valid evidence of the potential benefit of this procedure.

[What are at present the real hopes of pregnancy after ovarian cryopreservation?]

Survival rates for cancers that occur in childhood and adolescence have improved over the last decades, and preservation of future fertility in these patients has become a relevant issue. Premature ovarian failure is a consequence of exposing women to chemotherapeutic drugs and ionizing radiation. Ovarian cryopreservation is an alternative to cryopreservation of embryos or oocytes for theses patients. Ovarian cryopreservation aims to reimplant ovarian tissue after complete remission into the pelvic cavity (orthotopique site) or a heterotopic site like the abdominal wall or the forearm. In vitro folliculogenesis, that aims at the maturation of ovarian cortex primordial follicles cryopreserved for a FIV, is still in an experimental research stage. In this review, the objective was to evaluate the real hopes of pregnancy after ovarian cryopreservation. Indeed, many teams offer ovarian cryopreservation at present time, although only two pregnancies have been achieved to date. In both cases, it can be discussed whether the fertilized oocyte originated from the transplant or from the native ovary. Furthermore, the potential for reintroduction of cancerous cells may limit this technique in cancers that are known to have a risk of ovarian dissemination. The hopes engendered by ovarian cryopreservation, but also its limits, must be explained to the patients before an ovarian surgery for cryopreservation.