Preliminary experience of ovarian tissue cryopreservation procedure: alternatives, perspectives and feasibility

Ovarian tissue autotransplantation improves longevity in mice

In this study, we show the improvement in life longevity in an experimental mouse model after step-by-step autologous ovarian transplantation and compare its effects with exogenic transdermal estradiol usage. This has proven to be more efficient than "traditional" hormonal replacement therapy. Despite the high speed and effectiveness of estradiol replacement deficiency in blood by its oral or transdermal use, no significant increase in the life longevity of animals and possibly in women was noted. The function of the transplanted fragment is usually limited to 6-12 months. This is enough for oncofertility purposes, sometimes, but not for longevity improvement. We performed periodical tissue return (autologous transplantation), containing both the cortex and medulla in the experimental mouse model, which resulted in a statistically reliable improvement in longevity. Our experience indicates the important role of medullary ovarian factors in slowing the aging process in the body and increasing the life expectancy in the experiment. As shown, the transdermal estrogen supportive therapy for ovarian deficiency improves estrogen levels but causes much slower decreases in the follicle stimulating hormone (FSH) and luteinizing hormone (LH). Moreover, we attained the best longevity with step-by-step periodic ovarian autotransplantation, thus making "prosthetics" of ovarian function longer than it is preplanned physiologically [direct correlation between the levels of FSH and lifespan (r = 0.98)]. The experimental model we suggested could be projected to other mammals or humans as cortical transplantation provides the same results for reproduction restoration in mice and humans and even for hormone level normalization, but there is still a lack of information about anti-aging factors in the ovarian medulla and cortex. Hence, we consider that the most important factor for the anti-aging ovarian transplantation technology is to preserve and transfer both the medulla and cortex as parts of the whole ovary.

Effects of Ovarian Tissue Cryopreservation on Primary Ovarian Insufficiency in Girls Undergoing Bone Marrow Transplantation

OBJECTIVE

To determine if removing an ovary for ovarian tissue cryopreservation (OTC) increased rates of primary ovarian insufficiency (POI) in girls undergoing bone marrow transplantation (BMT). Institutional review board approval was obtained from all 3 clinical sites.

DESIGN

Multicenter retrospective cohort study SETTING: Academic children's hospitals PATIENTS: Females aged 2-21 who underwent BMT with or without OTC from 2010 to 2017.

INTERVENTIONS

None MAIN OUTCOME MEASURES: Rates of POI in girls who underwent OTC vs those who underwent BMT alone as determined by serum markers, presence of menses, or clinical diagnosis.

RESULTS

A total of 142 patients were identified, 43 who had OTC and 99 with BMT alone. The rate of POI in girls undergoing OTC was 65% vs 41.8% in those who underwent BMT alone (P = .26).

CONCLUSIONS

Although this study was not powered to detect a lack of difference, it is reassuring that there does not seem to be a clinically significant increase in POI in patients undergoing OTC.

In-vitro maturation and transplantation of cryopreserved ovary tissue: understanding ovarian longevity

RESEARCH QUESTION

Is it possible to use experience gained from 24 years of frozen ovarian transplantation, and from recent experience with in-vitro gametogenesis to accomplish simple and robust in-vitro maturation (IVM) of oocytes from human ovarian tissue?

DESIGN

A total of 119 female patients between age 2 and 35 years old underwent ovary cryopreservation (as well as in-vitro maturation of oocytes and IVM in the last 13 individuals) over a 24-year period. Up to 22 years later, 17 returned to have their ovary tissue thawed and transplanted back.

RESULTS

Every woman had a return of ovarian function 5 months after transplant, similar to previous observations. As observed before, anti-Müllerian hormone (AMH) concentration rose as FSH fell 4 months later. The grafts continued to work up to 8 years. Of the 17, 13 (76%) became pregnant with intercourse at least once, resulting in 19 healthy live births, including six live births from three women who had had leukaemia. Of the harvested germinal vesicle oocytes, 35% developed with simple culture media into mature metaphase II oocytes.

CONCLUSIONS

The authors concluded the following. First, ovary tissue cryopreservation is a robust method for preserving fertility even for women with leukaemia, without a need to delay cancer treatment. Second, many mature oocytes can often be obtained from ovary tissue with simple media and no need for ovarian stimulation. Third, ovarian stimulation only be necessary for removing the oocyte from the ovary, which can also be accomplished by simple dissection at the time of ovary freezing. Finally, pressure and just eight 'core genes' control primordial follicle recruitment and development.

Fertility and hormone preservation and restoration for female children and adolescents receiving gonadotoxic cancer treatments: A systematic review

BACKGROUND/PURPOSE

The purpose of this systematic review by the American Pediatric Surgical Cancer Committee was to summarize evidence from the current medical literature regarding fertility restoration and hormone replacement for female children and adolescents treated with gonadotoxic treatments.

METHODS

Using PRISMA guidelines, questions were addressed by searching Medline, Cochrane, Embase Central and National clearing house databases using relevant search terms. Eligible studies included those that addressed ovarian tissue cryopreservation (OTC), oocyte harvest, ovarian transposition, and ovarian tissue auto-transplantation for females under the age of 20. Four reviewers independently screened studies for eligibility, extracted data and assessed the risk of bias. Study outcomes were summarized in a narrative synthesis.

RESULTS

Two thousand two hundred seventy-six studies were identified by database search and manual review and 2185 were eliminated based on defined exclusion criteria. Ninety-one studies served as the basis for the systematic review. There were 1019 patients who underwent OTC with ages ranging from 0.4 to 20.4 years old, with 298 under the age of 13. Twenty patients aged 13-20 years old underwent successful oocyte harvest. Thirty-seven children underwent ovarian transposition as a means of fertility preservation. Eighteen patients underwent auto-transplantation of thawed ovarian cortical tissue that was harvested before the age of 21 years resulting in 10 live births.

CONCLUSIONS

Clinically accepted and experimental fertility preservation options such as OTC, oocyte cryopreservation, and ovarian transposition are available to females aged 20 years and younger who are at risk for premature ovarian insufficiency and infertility due to gonadotoxic treatments. There is a large cohort of pediatric-aged patients, with a wide variety of diagnoses and treatments, who have undergone fertility preservation. Currently, fertility and hormone restoration experience for patients who were 20- years of age or younger at the time of fertility preservation remains limited.

LEVEL OF EVIDENCE

IV.

Ultrastructure and intercellular contact-mediated communication in cultured human early stage follicles exposed to mTORC1 inhibitor

The reproductive lifespan of a woman is determined by the gradual recruitment of quiescent follicles into the growing pool. In humans, ovarian tissue removal from its in vivo environment induces spontaneous activation of resting follicles. Similarly, pharmacological activation of the PI3K/Akt pathway leads to accelerated follicle recruitment, but has been associated with follicular damage. Recent findings demonstrate that everolimus (EVE), an mTORC1 inhibitor, limits primordial follicle activation. However, its potential benefit regarding growing follicle integrity remains unexplored. Ovarian cortical fragments were exposed to ± EVE for 24 h and cultured for an additional 5 days. After 0, 1 and 6 days of culture, fragments were either processed for ultrastructural analysis or subjected to follicular isolation for gene expression and immunofluorescence assessments. Data from transmission electron microscopy showed that growing follicles displayed similar ultrastructural features irrespective of the conditions and maintained close contacts between germinal and stromal compartments. Establishment of intra-follicular communication was confirmed by detection of a gap junction component, Cx43, in both groups throughout culture, whereas transzonal projections, which physically link granulosa cells to oocyte, formed later in EVE-treated follicles. Importantly, levels of GJA1 mRNA, encoding for the Cx43 protein, significantly increased from Day 0 to Day 1 in the EVE group, but not in the control group. Given that EVE-treated follicles were smaller than controls, these findings suggest that EVE might facilitate the establishment of appropriate intercellular communications without impairing follicle ultrastructure. Therefore, mTORC1 inhibitors might represent an attractive tool to delay the culture-induced primordial follicle activation while maintaining follicles in a functionally integrated state.

Cryopreservation and transplantation of ovarian tissue: results from one center in the USA

Purpose

To report the results of cryopreserved ovary tissue transplantation for leukemia and other cancers, in a single US center.

Methods

One hundred eight females between age 6 and (median age 24) 35 were referred for possible ovary tissue cryopreservation over a 20-year period, with either slow freeze or vitrification. Thus far 13 patients returned up to 18 years later to have their tissue transplanted back.

Results

All 13 patients had return of ovarian function 5 months post transplant with regular menstrual cycling. AMH rose to very high levels as the FSH declined to normal. Four months later, the AMH again declined to very low levels. Nonetheless, the grafts remained functional for up to 5 years or longer. Ten of the 13 (77%) became spontaneously pregnant at least once, resulting in 13 healthy babies. A total of 24 healthy babies have been born 11 from fresh transplanted ovarian tissue and 13 from cryopreserved transplanted ovarian tissue.

Conclusions

(1) Ovary tissue cryopreservation is a robust method for preserving a woman’s fertility. (2) Cortical tissue pressure may be a key regulator of primordial follicle arrest, recruitment, and ovarian longevity. (3) This is the only such series yet reported in the USA.

Outcomes of immature oocytes collected from ovarian tissue for cryopreservation in adult and prepubertal patients

The efficiency of oocyte in-vitro maturation (IVM) and vitrification procedures after ex-vivo collection from ovarian tissue were assessed according to patient age, number of retrieved oocytes and tissue transport conditions. The combined procedure was performed in 136 patients: 130 adults (mean 27.6 ± 5.6 years) and six prepubertal girls (mean 8.7 ± 2.3 years). A higher mean number of oocytes were collected in girls compared with adults (11.5 ± 8.0 versus 3.8 ± 4.2, respectively, P < 0.001) but the percentage of degenerated oocytes was significantly higher in girls (35.5% versus 17.1%, respectively, P < 0.001). IVM rates were significantly lower in prepubertal than postpubertal population (10.3% versus 28.1%, P = 0.002). In adults, a negative correlation was observed between number of retrieved oocytes and age (P = 0.002; r = -0.271); the correlation was positive between anti-Müllerian hormone (AMH) and number of collected oocytes (P = 0.002; r = 0.264). IVM rates were not correlated with AMH levels (r = 0.06) or age (r = -0.033). At present, nine oocytes and one embryo have been warmed in four patients and one biochemical pregnancy obtained. This suggests the combined procedure could be an additional option for fertility preservation.

Chapter 13 Human Ovarian Tissue Vitrification

Ovarian freezing and transplantation has garnered increasing interest as a potential way of preserving fertility in cancer patients as well as for women who just wish to delay childbearing. This chapter spells out our techniques of ovarian cortex vitrification and results for frozen compared to fresh ovarian cortex transplantation (in one single series from one center for the sake of consistency), as well as potentially provides insight into the mechanism behind ovarian follicle recruitment. This represents an effort to simplify and popularize an approach that has yielded favorable results (all cases recovered ovulation and 75% had successful spontaneous pregnancy) in one single, disciplined study. It should be clear that this is a review for the more general reader of our original scientific papers published in Reproductive BioMedicine Online, New England Journal of Medicine, Fertility and Sterility, Human Reproduction, Molecular Human Reproduction, and Journal of Assisted Reproduction and Genetics (JARG).

Ovarian tissue cryopreservation and transplantation among alternatives for fertility preservation in the Nordic countries - compilation of 20 years of multicenter experience

Introduction

The aim of this study is to report the current status of ovarian tissue cryopreservation among alternatives for fertility preservation in the Nordic countries.

Material and methods

A questionnaire was sent to 14 Nordic academic reproductive centers with established fertility preservation programs. It covered fertility preservation cases performed up to December 2014, standard procedures for ovarian tissue cryopreservation and oocyte cryopreservation and reproductive outcomes following ovarian tissue transplantation.

Results

Among the Nordic countries, Denmark and Norway practice ovarian tissue cryopreservation as a clinical treatment (822 and 164 cases, respectively) and their programs are centralized. In Sweden (457 cases), ovarian tissue cryopreservation is practiced at five of six centers and in Finland at all five centers (145 cases). Nearly all considered ovarian tissue cryopreservation to be experimental. In Iceland, embryo cryopreservation is the only option for fertility preservation. Most centers use slow‐freezing methods for ovarian tissue cryopreservation. Most patients selected for ovarian tissue cryopreservation were newly diagnosed with cancer and the tissue was predominantly retrieved laparoscopically by unilateral oophorectomy. Only minor complications were reported. In total, 46 women have undergone ovarian tissue transplantation aiming at recovering fertility, 17 healthy children have been born and several additional pregnancies are currently ongoing. Whenever patients’ clinical condition is permissive, oocyte cryopreservation after hormonal stimulation is preferred for fertility preservation. Between 2012 and 2014, a smaller proportion of females have undergone fertility preservation in the Nordic centers, in comparison to males (1:3).

Conclusions

Overall, ovarian tissue cryopreservation was reported to be safe. Slow freezing methods are still preferred. Promising results of recovery of fertility have been reported in Nordic countries that have initiated ovarian tissue transplantation procedures.

How ovarian transplantation works and how resting follicle recruitment occurs: a review of results reported from one center

Ovarian freezing and transplantation has garnered increasing interest as a potential way of preserving fertility in cancer patients. This special report aims to identify the success rate of frozen compared with fresh ovarian cortex transplantation (in one single series from one center for the sake of consistency), as well as potentially provides insight into the mechanism behind ovarian follicle recruitment. A comparison of fresh versus frozen transplantation techniques is presented, highlighting the similarity and differences between the fresh and frozen transplantation procedures. Much of the literature is scattered case reports with different patient populations and different techniques. This represents an effort to simplify and popularize an approach that has yielded favorable results (all cases recovered ovulation and 75% had successful spontaneous pregnancy) in one single, disciplined study.

Fresh and cryopreserved ovary transplantation and resting follicle recruitment

Ovary cryopreservation and transplantation has garnered increasing interest as a possible method to preserve fertility for cancer patients and to study ovarian resting follicle recruitment. Eleven consecutive women underwent fresh donor ovary transplantation, and 11 underwent cryopreserved ovary auto-transplantation in the same centre, with the same surgeon. Of the 11 fresh transplant recipients, who were all young but menopausal, nine women had normal ovarian cortex transplanted from an identical twin sister, and two had a fresh allograft from a non-identical sister. In the second group, 11 women with cancer had ovarian tissue cryopreserved before bone marrow transplant, and then after years of therapeutically induced menopause, underwent cryopreserved ovarian cortex autotransplantation. Recovery of ovarian function and follicle recruitment was assessed in all 22 recipients, and the potential for pregnancy was further investigated in 19 (11 fresh and 8 cryopreserved) with over 1-year follow-up. In all recipients, normal FSH levels and menstruation returned by about 150 days, and anti-Müllerian hormone reached much greater than normal concentrations by about 170 days. Anti-Müllerian hormone levels then fell below normal by about 240 days and remained at that lower level. Seventeen babies have been born to these 11 fresh and eight cryopreserved ovary transplant recipients.

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.

Effects of growth differentiation factor-9 and FSH on in vitro development, viability and mRNA expression in bovine preantral follicles

The present study investigated the role of growth differentiation factor (GDF)-9 and FSH, alone or in combination, on the growth, viability and mRNA expression of FSH receptor, proliferating cell nuclear antigen (PCNA) and proteoglycan-related factors (i.e. hyaluronan synthase (HAS) 1, HAS2, versican, perlecan) in bovine secondary follicles before and after in vitro culture. After 12 days culture, sequential FSH (100 ng mL–1 from Days 0 to 6 and 500 ng mL–1 from Days 7 to 12) increased follicular diameter and resulted in increased antrum formation (P < 0.05). Alone, 200 ng mL–1 GDF-9 significantly reduced HAS1 mRNA levels, but increased versican and perlecan mRNA levels in whole follicles, which included the oocyte, theca and granulosa cells. Together, FSH and GDF-9 increased HAS2 and versican (VCAN) mRNA levels, but decreased PCNA mRNA expression, compared with levels in follicles cultured in α-minimum essential medium supplemented with 3.0 mg mL–1 bovine serum albumin, 10 µg mL–1 insulin, 5.5 µg mL–1 transferrin, 5 ng mL–1 selenium, 2 mM glutamine, 2 mM hypoxanthine and 50 μg mL–1 ascorbic acid (α-MEM+). Comparisons of uncultured (0.2 mm) and α-MEM+ cultured follicles revealed that HAS1 mRNA expression was higher, whereas VCAN expression was lower, in cultured follicles (P < 0.05). Expression of HAS1, VCAN and perlecan (HSPG2) was higher in cultured than in vivo-grown (0.3 mm) follicles. In conclusion, FSH and/or GDF-9 promote follicular growth and antrum formation. Moreover, GDF-9 stimulates expression of versican and perlecan and interacts positively with FSH to increase HAS2 expression.

Evaluation of ovarian and testicular tissue cryopreservation in children undergoing gonadotoxic therapies

OBJECTIVE

Ovarian and testicular tissue cryopreservation are the only fertility preservation options for sexually immature individuals. Because of their experimental nature, it is important to determine safety and possible bundling with other medicallyindicated procedures.

STUDY DESIGN

Prospective observational.

RESULTS

Cryopreservation indications included cancer in 75 % of females and 50 % of males, while non-cancer indications included various hematological conditions. Similar numbers of females (12/28) and males (3/9) underwent prior chemotherapy. Females underwent laparoscopic (27/28) or robotic (1/28) approaches while incisional biopsy was used in males. Bundling of ovarian and testicular harvesting with other medicallyindicated procedures was performed in 42 % and 22 %, respectively. The operative time inclusive of bundled procedures was similar (1.6 ± 0.1 vs. 0.9 ± 0.3 h) but the discharge time was significantly longer for females than males (10.4 ± 0.6 vs. 4.6 ± 0.6 h, p<0.05) due to frequent bundling of medically-indicated procedures in females. All procedures were successfully completed without complications or significant blood loss.

CONCLUSIONS

Pediatric gonadal tissue cryopreservation can be combined with other medically-indicated procedures to minimize the potential inconvenience, additional anesthetic risks, and costs.

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.

Multiple approaches for individualized fertility protective therapy in cancer patients

In the last decade, fertility preservation has risen as a major field of interest, creating new interactions between oncologists and gynecologists. Various options, such as cryopreservation of ovarian tissue, have been developed and are currently routinely proposed in many centers. However, many of the options remain experimental and should be offered to patients only after adequate counseling. This paper addresses the efficiency and the potential of the different fertility preservation approaches.

Vitrification of in vitro matured oocytes collected from antral follicles at the time of ovarian tissue cryopreservation

BACKGROUND

In the past few years, cryopreservation of ovarian tissue has become an established procedure proposed in many centers around the world and transplantation has successfully resulted in full-term pregnancies and deliveries in human. This prospective study aims to evaluate the feasibility of vitrifying in vitro matured oocytes (IVM) isolated at the time of ovarian tissue cryopreservation to improve the efficiency of fertility preservation programs.

METHODS

Oocyte-cumulus complexes were retrieved from freshly collected ovarian cortex by aspirating antral follicular fluid, and were matured in vitro for 24-48 h prior to vitrification. Oocytes were matured in an IVM commercial medium (Copper Surgical, USA) supplemented with 75 mIU/ml FSH and 75 mIU/ml LH and vitrified using a commercial vitrification kit (Irvine Scientific, California) in high security vitrification straws (CryoBioSystem, France). Oocyte collection and IVM rates were evaluated according to the age, the cycle period and the amount of tissue collected.

RESULTS

Immature oocyte retrieval from ovarian tissue was carried out in 57 patients between 8 and 35 years of age, undergoing ovarian tissue cryopreservation. A total of 266 oocytes were isolated, 28 of them were degenerated, 200 were at germinal vesicle stage (GV), 35 were in metaphase I (MI) and 3 displayed a visible polar body (MII). The number of oocytes collected was positively correlated with the amount of tissue cryopreserved (p < 0.001) and negatively correlated with the age of the patients (p = 0.005). Oocytes were obtained regardless of menstrual cycle period or contraception. A total maturation rate of 31% was achieved, leading to the vitrification of at least one mature oocyte for half of the cohort.

CONCLUSIONS

The study showed that a significant number of immature oocytes can be collected from excised ovarian tissue whatever the menstrual cycle phases and the age of the patients, even for prepubertal girls.

Fertility Preservation in Women with Cancer: Importance of a Multidisciplinary Approach

For all patients affected by a disease that could impair fertility before or during the reproductive lifespan, strategies to preserve their fertility and the ability to bear their own children is likely to be of utmost importance. While fertility preservation is a promising option, most of the technologies currently used are far from being well-established or are still experimental. Patients should be aware that no method guarantees success. Psychological and ethical impacts of fertility preservation are major concerns and should be included in the multidisciplinary approach to the patients.

Xenotransplantation of cryopreserved ovarian tissue from patients with ovarian tumors into SCID mice--no evidence of malignant cell contamination

This study examined the possible presence of malignant cells in ovarian cortex from patients with ovarian tumors after xenografting of the ovarian tissue into severe combined immunodeficiency mice. None of the mice presented symptoms of reintroduced malignancy nor did microscopic and immunohistochemical evaluation of the grafts raise any suspicion of residual malignant disease.

Follicular interactions affect the in vitro development of isolated goat preantral follicles

The aim of this study was to evaluate the influence of the number of follicles per drop (one or three) and antral follicles on in vitro development of isolated goat preantral follicles. Preantral follicles were isolated through microdissection and distributed individually (control) or in groups of three follicles (treatment) in microdroplets of α-MEM with or without 1000 ng/ml follicle stimulating hormone (FSH) for Experiments 1 and 2, respectively. Experiment 3 was divided into four treatments according to the presence of one or three preantral follicles, associated or not with antral follicles. After culture, oocytes were retrieved from morphologically normal follicles and submitted to in vitro maturation (IVM) and live/dead fluorescent labelling. Results of Experiment 1 (basic medium without FSH) showed that culture of preantral follicles in groups enhances viability, growth and antrum formation after 12 days. However, in the presence of FSH (Experiment 2), only the recovery rate of fully grown oocytes for IVM was significantly affected by grouping of follicles. In Experiment 3, in general, co-culture of preantral follicles with an early antral follicle had a detrimental effect on viability, antrum formation and production of oocytes for IVM. In conclusion, the performance of in vitro culture of goat preantral follicles is affected by the number of follicles per drop, the presence of an antral follicle and FSH.

Orthotopic and heterotopic ovarian tissue transplantation

BACKGROUND

Transplantation of ovarian tissue is, at present, the only clinical option available to restore fertility using cryopreserved ovarian tissue. More than 30 transplantations of cryopreserved tissue have been reported, and six babies have been born, worldwide, following this procedure. Despite these encouraging results, it is essential to optimize the procedure by improving the follicular survival, confirming safety and developing alternatives. Here, we review the different factors affecting follicular survival and growth after grafting.

METHODS

Relevant studies were identified by searching Pubmed up to January 2009 with English language limitation. The following key words were used: (ovarian tissue or whole ovary) AND (transplantation) AND (cryopreservation or pregnancy). Using the literature and personal experience, we examined relevant data on the different exogenous and clinical factors affecting follicular development after grafting.

RESULTS

Clinical factors such as the patient's age and the transplantation sites influenced the lifespan of the graft. A heterotopic transplantation site is not optimal but offers some advantages and it may also promote the hormonal environment after a combined heterotopic and orthotopic transplantation. Exogenous factors such as antioxidants, growth factors or hormones were tested to improve follicular survival; however, their efficiency regarding further follicular development and fertility potential remains to be established.

CONCLUSION

Additional evidence is required to define optimal conditions for ovarian tissue transplantation. Alternatives such as whole ovary or isolated follicles transplantations require further investigation but are likely to be successful in humans in the future.

Female fertility preservation: practical and ethical considerations of an underused procedure

PURPOSE

Cancer treatments for young women can permanently or temporarily affect fertility. The purpose of this retrospective analysis was to present the clinical experience and ethical considerations of fertility preservation in female oncology patients in a tertiary gynaecological department.

METHODS

Since 2002, in 37 patients fertility preservation was performed according to an institutional review board approved protocol in a University hospital in the Netherlands; 33 patients were not treated.

RESULTS

Embryo cryopreservation was performed in 10 patients, ovarian tissue cryopreservation in 24, and an ovarian transposition was performed in 3 patients; in one patient combined with an ovarian transplantation and in one patient with ovarian tissue cryopreservation.

DISCUSSION

Approved protocols and timing are essential in performing female fertility preservation. Referral for ovarian tissue and embryo cryopreservation is minimal in the Netherlands. Future research focuses on the psychosocial aspects of fertility preservation and explores patients' and professionals' expectations and attitudes regarding fertility preservation and aims to be in line with technical developments.

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.

Fertility preservation: successful transplantation of cryopreserved ovarian tissue in a young patient previously treated for Hodgkin's disease

Cryopreservation of ovarian tissue is now offered as an experimental procedure to preserve the fertility of young patients with a high risk for premature ovarian failure resulting from cancer therapy. This is the only available option to preserve the fertility of prepubertal patients treated with gonadotoxic chemotherapy. At present, thousands of patients all over the world have undergone this procedure with the hope of later restoring their fertility. Although the efficiency of the transplantation of cryopreserved ovarian tissue to restore ovarian function has been established, reports of pregnancy are still very scarce. Here, we describe the second published full-term spontaneous pregnancy after an orthotopic and heterotopic transplantation of cryopreserved ovarian tissue in a 31-year-old woman previously treated by conditioning therapy for bone marrow transplantation for Hodgkin's disease. This birth gives compelling evidence for the graft origin of the gamete and confirms the efficacy of ovarian tissue transplantation in restoring human natural fertility after oncological treatment. This case report stresses the importance of proposing the ovarian tissue cryopreservation procedure to all young patients who require potentially sterilizing treatment, with all alternative options to preserve fertility being duly taken into consideration.

Premature ovarian failure: a review

OBJECTIVES

To present an updated review on the etiology, consequences and management of premature ovarian failure.

DESIGN

A search of the English language literature using the Cochrane Library database and Medline 1966-2006, with a hand search of the references.

CONCLUSION

Premature ovarian failure is defined as the occurrence of amenorrhea, hypergonadotropinemia and estrogen deficiency in women under the age of 40 years, with the prevalence being 0.9-1.2%. In the majority of cases, the etiology is unknown, but known causes include chemotherapy, radiotherapy, surgery, genetic disorders, particularly involving the X chromosome, associations with autoimmune diseases, infections, smoking and other toxins. The three critical issues of management in these women are the effect of the diagnosis on the psychological health of the patient, the consequent infertility and the long- and short-term effects of estrogen deficiency arising from ovarian decline. Promising methods of screening for premature ovarian failure are being developed.

The effect of a GnRH agonist on cryopreserved human ovarian grafts in severe combined immunodeficient mice

This prospective study compares the effect of a GnRH agonist on the number of follicles in different developmental stages in cryopreserved human ovarian grafts transplanted into gonadotropin-stimulated or not stimulated severe combined immunodeficient mice (SCID mice). Human ovarian tissue from seven patients was cryopreserved with an open-freezing system and xenotransplanted in SCID mice. The SCID mice were then treated according to different stimulation protocols. The survival of the tissue after cryopreservation was examined by LIVE/DEAD viability staining or transplanted in the neck muscle of 41 SCID mice. Development of follicles, estradiol production, vaginal cytology, and uterus weight were assessed after 15 weeks with or without gonadotropin stimulation. Viable follicles were detected in all frozen/thawed specimens using the LIVE/DEAD assay. Triptorelin, a GnRH agonist, caused a significant reduction of follicles in all developmental stages in the non-gonadotropin-stimulated animals (P<0.001). In gonadotropin-stimulated animals, GnRH agonist treatment has no significant effect on primordial, primary and preantral follicle count, whereas the antral follicles were significantly fewer (P= 0.03). The GnRH agonist treatment is not able to prevent the primordial follicle depletion after the xenografting of ovarian tissue in SCID mice with or without gonadotropin stimulation. Furthermore, it causes an additional loss of follicles if administered during the critical neovascularization period after the transplantation.

Significant loss of primordial follicles after prolonged gonadotropin stimulation in xenografts of cryopreserved human ovarian tissue in severe combined immunodeficient mice

This study evaluated the effect of gonadotropin stimulation on the primordial follicle reserve of cryopreserved human ovarian tissue after transplantation in severe combined immunodeficient mice. We found that prolonged gonadotropin stimulation significantly reduces primordial follicles.

Comparison of two freezing protocols in an open freezing system for cryopreservation of rat ovarian tissue

AIM

To compare two freezing protocols in an automatic open-vessel freezing system for cryopreservation of rat ovarian tissue.

METHODS

Ovarian tissue was transplanted heterotopically into the neck muscle, either without cryopreservation (group 1, n = 6) or with cryopreservation after equilibration with 1.5 mol/L dimethyl sulfoxide and propanediol (protocol A, group 2, n = 6) or 1.5 mol/L ethyl glycol (protocol B, group 3, n = 6). The ovarian tissue was examined with LIVE/DEAD fluorescent viability staining and histologically after isotransplantation.

RESULTS

The healthy follicular loss (intact oocyte and >50% granulosa cells alive) due to cryopreservation was 15.5% with protocol A and 12.2% with protocol B. Histological examination showed follicles in all developmental phases in all groups: group 1, 35.5 +/- 5.7/mm(2) (mean +/- SD); group 2, 16.0 +/- 5.0/mm(2); group 3, 17.3 +/- 5.7/mm(2). The differences between groups 1 and 2 and between groups 1 and 3 were significant (P < 0.001). The difference between groups 2 and 3 was not significant (P = 0.33).

CONCLUSIONS

These results demonstrate that the use of an open freezing system with both freezing protocols allows cryopreservation of rat ovarian tissue with equally good survival rates.

Ovarian function and spontaneous pregnancy after combined heterotopic and orthotopic cryopreserved ovarian tissue transplantation in a patient previously treated with bone marrow transplantation: case report

Cryopreservation of ovarian tissue has been proposed for storing gametes of young patients at high risk of premature ovarian failure. Autotransplantation has recently provided some promising results and is still the unique option to restore ovarian function from cryopreserved ovarian tissue in humans. In this article, we analyse data from the combined orthotopic and heterotopic transplantation of cryopreserved ovarian tissue that restored the ovarian function and fertility. Orthotopic transplantation of cryopreserved ovarian tissue at ovarian and peritoneal sites, together with a heterotopic transplantation at the abdominal subcutaneous site, was performed to restore the ovarian function of a 29-year-old woman previously treated with bone marrow transplantation (BMT) for Hodgkin's disease. Ovarian reserve markers progressively suppress within values 5 months after the transplantation (basal FSH 5 mUI/ml and inhibin B 119 ng/ml). Follicular development was observed at all transplantation sites but was predominant at the ovarian site. Six natural cycles were fully documented and analysed. The patient became spontaneously pregnant following the sixth cycle, but unfortunately she later miscarried. Combined orthotopic and heterotopic transplantations succeeded in the restoration of normal spontaneous cycles. Furthermore, this spontaneous pregnancy confirmed the efficiency of this procedure for restoring human fertility.

Orthotopic microvascular reanastomosis of whole cryopreserved ovine ovaries resulting in pregnancy and live birth

OBJECTIVE

To evaluate the feasibility of contralateral autotransplantation of cryopreserved whole ovaries with microanastomosis of the ovarian vascular pedicle.

DESIGN

Animal study.

SETTING

Department of Biomedical Sciences, General Hospital of Vienna, Austria.

ANIMAL(S)

Nine ewes, six month of age.

INTERVENTION(S)

Laparotomic unilateral oophorectomy was performed. Ovaries were frozen using a controlled-rate freezing system. After frozen storage, contralateral laparotomic oophorectomy was performed, and the thawed ovaries were returned to the contralateral orthotopic site with microsurgical vascular anastomosis.

MAIN OUTCOME MEASURE(S)

Histologic examination and serum follicle-stimulating hormone and progesterone levels.

RESULT(S)

Four sheep showed postoperative luteal function. One sheep conceived after spontaneous intercourse and delivered a healthy lamb 545 days after transplantation. Histologic examination of the ovaries 18-19 months after transplantation showed that the structural integrity of the ovarian stroma had largely been retained in six out of nine animals. Follicular survival rate in the grafted ovaries was 1.7%-7.6%.

CONCLUSION(S)

Microvascular anastomosis of whole ovaries and orthotopic transplantation after cryopreservation is technically feasible and a promising procedure in ovarian tissue banking.

Simple Prediction of the Survival of Follicles in Cryopreserved Human Ovarian Tissue

This study examines the possible predictive value of the LIVE/DEAD fluorescence viability assay for evaluation of survival of cryopreserved human ovarian tissue. Ovarian tissue from ten patients was examined by LIVE/DEAD viability staining before and after cryopreservation and after freezing in a -20 C freezer (negative control). After cryopreservation with a slow freezing protocol and cryoprotectant the LIVE/DEAD assay showed 86% viable follicles (an intact oocyte and at least more than 50% of the granulosa cells alive), whereas after freezing at -20 C the survival rate was 67%. The healthy follicular loss after cryopreservation was 4%, whereas with freezing at -20 C, it was 25%. Although this assay overestimates the survival rate of cryopreserved primordial follicles, if the LIVE/DEAD assay yields greater than approximately 85% viable follicles, it can be assumed that the follicles in the cryopreserved tissue have maintained their developmental potential and that the tissue is suitable for retransplantation.

Follow-up of ovarian function post-chemotherapy following ovarian cryopreservation and transplantation

BACKGROUND

The purpose of this study was to assess the ovarian function after treatment of a malignant disease in women who previously had cortical tissue from an entire ovary cryopreserved prior to chemotherapy, and to assess ovarian function after autotransplantation of cryopreserved ovarian tissue. All were treated with chemotherapeutic drugs with an estimated high risk of inducing ovarian failure.

METHODS

Twenty-two women with breast cancer (n = 8), Hodgkin's disease (n = 6), non-Hodgkin's (n = 2), leukaemia (n = 5) or brain tumour (n = 1) underwent a clinical examination >18 months after cryopreservation. Three patients with premature ovarian failure had ovarian tissue autotransplanted orthotopically and heterotopically. Ovarian function was assessed by ultrasonography of the remaining ovary and hormone measurements.

RESULTS

Nine of 22 women (41%) had sonographic and hormonal signs of ovarian failure with ovarian volumes <1.3 cm3, no antral follicles and high FSH levels (median 57.1 IU/l). Thirteen of the 22 women (59%) still menstruated and 10 had a seemingly normal ovarian function, with a median ovarian volume of 6.8 cm3, a median number of antral follicles of six, FSH <15 IU/l and normal estradiol levels. All three patients with autotransplanted ovarian tissue regained ovarian function as confirmed by return of menses, follicles on ultrasonography and normalized hormone levels. Two embryos were created from the crypreserved tissue after IVF.

CONCLUSIONS

Treatment with bone-marrow transplantation and/or high doses of alkylating agents led to ovarian failure in all patients. Autotransplantation of ovarian tissue led to return of ovarian function.

Impact of various endocrine and paracrine factors on in vitro culture of preantral follicles in rodents

Folliculogenesis is a complex process regulated by various paracrine and autocrine factors. In vitro growth systems of primordial and preantral follicles have been developed for future use of immature oocytes, as sources of fertilizable oocytes and for studying follicular growth and oocyte maturation mechanisms. Rodents were often chosen for in vitro follicular culture research and a lot of factors implicated in folliculogenesis have been identified using this model. To date, the mouse is the only species in which the whole process of follicular growth, oocyte maturation, fertilization and embryo transfer into recipient females was successfully performed. However, the efficiency of in vitro culture systems must still be considerably improved. Within the follicle, numerous events affect cell proliferation and the acquisition of oocyte developmental competency in vitro, including interactions between the follicular cells and the oocyte, and the composition of the culture medium. Effects of the acting factors depend on the stage of follicle development, the culture system used and the species. This paper reviews the action of endocrine, paracrine factors and other components of culture medium on in vitro growth of preantral follicles in rodents.

In-vitro maturation of germinal-vesicle oocytes and cryopreservation in metaphase I/II: a possible additional option to preserve fertility during ovarian tissue cryopreservation

This study describes the possibility of combining two options in order to preserve female fertility: cryopreservation of human ovarian tissue and in-vitro matured germinal vesicle (GV) oocytes retrieved during tissue dissection. In contrast to ovarian tissue cryopreservation, the cryostorage of in-vitro matured unfertilized metaphaseI/II oocytes could be a more realistic option. This concept of preserving fertility before chemotherapy and/or radiotherapy without a long time delay could be an additional reason for favouring ovarian tissue cryopreservation. This concept is discussed in regard to two cases.

Diagnostic assessment of the developmental potential of human cryopreserved ovarian tissue from multiple patients using xenografting

BACKGROUND

Although ovarian tissue cryopreservation for women at risk of losing ovarian function is offered by many clinics, there is a lack of evidence relating to the developmental potential of the stored tissue and, therefore, its clinical potential. This study was designed to use xenografting of cryopreserved tissue from multiple patients to assess the reproducibility of preservating developmental potential, the variation in developing follicle profile and the relationship between pre-freeze histology and post-thaw development.

METHODS

Using previously published methods, cryopreserved ovarian cortex from nine patients was thawed and grafted under the kidney capsules of immunodeficient mice. Development of follicles was assessed after 26 weeks and compared to histology prior to freezing.

RESULTS

Multiple growing follicles including antral stages were observed in multiple grafts of tissue from all patients. Metaphase II oocytes (n=9) were observed in follicles in grafts from five patients. There was no relationship between pre-freeze histology and developing follicle profile in xenografts.

CONCLUSIONS

The propanediol freezing method used in this study is capable of reproducibly preserving the developmental potential of human ovarian follicles. The developing follicle profile after cryopreservation cannot be accurately predicted from pre-freeze histology. Xenografting provides a powerful tool for assessing the potential of human cryopreserved ovarian tissue.

Orthotopic autotransplantation of cryopreserved ovarian tissue to a woman cured of cancer–follicular growth, steroid production and oocyte retrieval

Cryopreservation of human ovarian tissue is now an option for cancer patients facing treatment with gonadotoxic regimes, as a means of preserving their fertility. So far, there have been only a few reports on autotransplantation of frozen-thawed tissue with regard to restoration of ovarian function. The present report describes a 32-year-old woman diagnosed with Hodgkin's lymphoma, who had cryopreserved ovarian tissue transplanted orthotopically after secondary ovarian failure due to chemotherapy. Only 8 weeks after transplantation, ultrasonography of the remaining ovary revealed two follicles with diameters of 10 and 15 mm. Concomitantly, circulating concentrations of oestradiol increased, while concentrations of gonadotrophins decreased. In the following months, the patient menstruated three times. Subsequent pituitary down-regulation with a gonadotrophin-releasing hormone (GnRH) agonist and ovarian stimulation resulted in development of one pre-ovulatory follicle from which a metaphase II oocyte was retrieved; however, this oocyte was unable to sustain further development after intracytoplasmic sperm injection (ICSI). Intrafollicular concentrations of oestradiol and progesterone suggested a normal luteinizing response of the follicle to human chorionic gonadotrophin stimulation. A 7-month follow-up revealed continued vivid follicular activity and normal oestradiol concentrations. In conclusion, cryopreserved human ovarian tissue restored ovarian function for several cycles and sustained development of mature oocytes in a woman cured of cancer.