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

Restoring Ovarian Fertility and Hormone Function: Recent Advancements, Ongoing Efforts and Future Applications

The last 20 years have seen substantial improvements in fertility and hormone preservation and restoration technologies for a growing number of cancer survivors. However, further advancements are required to fill the gaps for those who cannot use current technologies or to improve the efficacy and longevity of current fertility and hormone restoration technologies. Ovarian tissue cryopreservation (OTC) followed by ovarian tissue transplantation (OTT) offers those unable to undergo ovarian stimulation for egg retrieval and cryopreservation an option that restores both fertility and hormone function. However, those with metastatic disease in their ovaries are unable to transplant this tissue. Therefore, new technologies to produce good-quality eggs and restore long-term cyclic ovarian function are being investigated and developed to expand options for a variety of patients. This mini-review describes current and near future technologies including in vitro maturation, in vitro follicle growth and maturation, bioprosthetic ovaries, and stem cell applications in fertility restoration research by their proximity to clinical application.

Research progress on mechanism of follicle injury after frozen ovarian tissue transplantation and protective strategies

The iatrogenic ovarian dysfunction caused by cancer treatment have been increasing, along with the age at onset of malignant tumors getting younger, the survival of cancer patients being longer, as well as the delayed childbearing age for females; therefore it becomes a major clinical challenge to preserve the fertility of these patients. Ovarian tissue cryopreservation is the only solution for female cancer patients in prepubertal ages and those who cannot delay gonadotoxic therapy. However, the successful rate of cryopreservation and transplantation of ovarian tissue is still low at present due to the risk of ischemia and hypoxia of grafted tissues. Abnormal activation of primordial follicle and ischemia-reperfusion injury after blood supply recovery also cause massive loss of follicles in grafted ovarian tissues. It has been tried in various studies to reduce the damage of follicles during freezing and transplantation by adding certain drugs, and extend the duration of endocrine and reproductive function in patients with ovarian transplantation. For example, melatonin, N-acetylcysteine, erythropoietin or other antioxidants are used to reduce oxidative stress; mesenchymal stem cells derived from different tissues, basic fibroblast growth factor, vascular endothelial growth factor, angiopoietin 2 and gonadotropin are used to promote revascularization; anti-Müllerian hormone and rapamycin are used to reduce abnormal activation of primordial follicles. This article reviews the research progress on the main mechanisms of follicle loss after ovarian tissue transplantation, including hypoxia, ischemia-reperfusion injury and associated cell death, and abnormal activation of follicles; and explores the methods of reducing graft follicle loss to provide reference for improving the efficiency of ovarian tissue cryopreservation and transplantation.

First report on successful delivery after retransplantation of vitrified, rapid warmed ovarian tissue in Europe

RESEARCH QUESTION

Cryopreservation of ovarian tissue is one feasible option to preserve female fertility prior to cancer treatment. The slow freezing protocol represents the current standard approach, while vitrification has been suggested as a promising alternative. This paper reports the follow-up and first successful delivery after retransplantation of vitrified, rapid warmed ovarian tissue in Europe.

DESIGN

After the patient received a diagnosis of breast cancer, ovarian tissue was removed laparoscopically and sent via overnight transportation to University Hospital Bonn for vitrification on site. The patient was treated with chemotherapy, leading to ovarian failure. After 2 years, retransplantation of the vitrified, rapid warmed tissue was conducted on site.

RESULTS

Two months after grafting, the patient reported regular menstrual cycles. After 1 further month a clinical pregnancy occurred, which ended in a spontaneous abortion at the 8th week of pregnancy. Six months after grafting, another naturally conceived pregnancy was determined, resulting in the birth of a healthy boy 14 months after retransplantation of the ovarian tissue.

CONCLUSIONS

Complementing the successful deliveries reported by the groups of Suzuki (Japan) and Silber (USA) regarding vitrified tissue, the current results confirm the high potential of this cryopreservation method in a clinical routine setting as an alternative approach to the widespread slow freezing method.

Ovarian tissue transplantation: 10 years of experience at the Bologna University

Objective

The efficiency of ovarian tissue transplantation (OTT) was established in terms of ovarian function recovery (95% of cases), number of live births (over 200 worldwide to date) and induction of puberty. Unfortunately, the lack of international registries and the fact that many centers have not yet reported their outcomes, lead to poor knowledge of the exact fertility data. The aim of the study is to describe our experience with OTT to restore ovarian function and fertility.

Methods

This study was designed as a single-center, observational, retrospective, cohort study that includes women who underwent OTT between December 2012 and June 2023 at our center. After approval by the oncologist/hematologist, a small fragment of ovarian tissue was thawed and analyzed to detect the presence of micrometastases before OTT. Thawed ovarian tissue was grafted laparoscopically at multiple sites, including the remaining ovary and pelvic side wall (orthotopic transplantation) and/or abdominal wall (heterotopic transplantation). After OTT, ovarian function was monitored by hormonal assay, ultrasound and color Doppler at approximately 4-week intervals.

Results

Between December 2012 and June 2023, 30 women performed OTT. Prior to OTT, immunohistochemical and molecular analyses revealed no micrometastases in all thawed ovarian tissue samples. In our series of 30 women, 20 of women were on premature ovarian insufficiency (POI), and the remaining ten cases still had oligomenorrhea and difficulty getting pregnant. Among the women with POI before OTT and at least 6 months follow-up, recovery of endocrine function was observed in all but one woman who underwent orthotopic transplantation (13 of 14 cases), in one out of two women who underwent both orthotopic and heterotopic transplantation (1 of 2 cases) and in all women who underwent heterotopic transplantation (4 of 4 cases). Women who underwent OTT to enhance fertility had no alterations in menstrual cycle and hormonal levels. In total, ten pregnancies were obtained in 25 women, resulting in four live births, two ongoing pregnancies and four spontaneous abortions.

Conclusion

Our data can help patients and physicians in their discussions and decisions about the need and possibilities of preserving fertility.

Current Position of Oncofertility in Adolescent Female Cancer Patients: A Comparative Review on Society Guidelines

Fertility preservation (FP) in pediatric and adolescent oncology patients presents a complex interplay between cancer treatment imperatives and reproductive aspirations, demanding a multi-disciplinary approach. Essential guidelines emphasize the importance of early referrals to FP specialists, ensuring timely counseling on oocyte and ovarian tissue cryopreservation options. Proper patient selection and risk assessment, considering intrinsic and extrinsic factors, is crucial for judicious resource utilization and optimal outcomes. Gonadotoxic effects of cancer treatments pose significant threats to reproductive capabilities. Oocyte cryopreservation (OC) is preferred in post-pubertal adolescents without partners. Cultural and religious concerns, especially regarding hymenal integrity, influence FP decisions, necessitating culturally sensitive consent processes. Ovarian tissue cryopreservation (OTC) offers an alternative for those unfit for OC. Despite its experimental label in some societies, emerging data support the efficacy of OTC, with ovarian tissue transplantation (OTT) showing promise in restoring ovarian function. However, the reintroduction of potentially malignant cells during transplantation remains a concern. Overall, while FP offers hope for future parenthood, the intricacies of decision-making and the potential medical, ethical, and cultural challenges underscore the importance of a personalized, multi-disciplinary approach. In this review, guidelines from various societies have been comprehensively reviewed and analyzed to provide insight into the clinical practice of oncofertility.

BRCA Mutations and Fertility Preservation

Hereditary cancers mostly affect the adolescent and young adult population (AYA) at reproductive age. Mutations in BReast CAncer (BRCA) genes are responsible for the majority of cases of hereditary breast and ovarian cancer. BRCA1 and BRCA2 act as tumor suppressor genes as they are key regulators of DNA repair through homologous recombination. Evidence of the accumulation of DNA double-strand break has been reported in aging oocytes, while BRCA expression decreases, leading to the hypothesis that BRCA mutation may impact fertility. Moreover, patients exposed to anticancer treatments are at higher risk of fertility-related issues, and BRCA mutations could exacerbate the treatment-induced depletion of the ovarian reserve. In this review, we summarized the functions of both genes and reported the current knowledge on the impact of BRCA mutations on ovarian ageing, premature ovarian insufficiency, female fertility preservation strategies and insights about male infertility. Altogether, this review provides relevant up-to-date information on the impact of BRCA1/2 mutations on fertility. Notably, BRCA-mutated patients should be adequately counselled for fertility preservation strategies, considering their higher sensitivity to chemotherapy gonadotoxic effects.

FGF2, LIF, and IGF1 (FLI) supplementation during human in vitro maturation enhances markers of gamete competence

STUDY QUESTION

Does a chemically defined maturation medium supplemented with FGF2, LIF, and IGF1 (FLI) improve in vitro maturation (IVM) of cumulus-oocyte complexes (COCs) obtained from children, adolescents, and young adults undergoing ovarian tissue cryopreservation (OTC)?

SUMMARY ANSWER

Although FLI supplementation did not increase the incidence of oocyte meiotic maturation during human IVM, it significantly improved quality outcomes, including increased cumulus cell expansion and mitogen-activated protein kinase (MAPK) expression as well as enhanced transzonal projection retraction.

WHAT IS KNOWN ALREADY

During OTC, COCs, and denuded oocytes from small antral follicles are released into the processing media. Recovery and IVM of these COCs is emerging as a complementary technique to maximize the fertility preservation potential of the tissue. However, the success of IVM is low, especially in the pediatric population. Supplementation of IVM medium with FLI quadruples the efficiency of pig production through improved oocyte maturation, but whether a similar benefit occurs in humans has not been investigated.

STUDY DESIGN, SIZE, DURATION

This study enrolled 75 participants between January 2018 and December 2021 undergoing clinical fertility preservation through the Fertility & Hormone Preservation & Restoration Program at the Ann & Robert H. Lurie Children's Hospital of Chicago. Participants donated OTC media, accumulated during tissue processing, for research.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants who underwent OTC and include a pediatric population that encompassed children, adolescents, and young adults ≤22 years old. All participant COCs and denuded oocytes were recovered from media following ovarian tissue processing. IVM was then performed in either a standard medium (oocyte maturation medium) or one supplemented with FLI (FGF2; 40 ng/ml, LIF; 20 ng/ml, and IGF1; 20 ng/ml). IVM outcomes included meiotic progression, cumulus cell expansion, transzonal projection retraction, and detection of MAPK protein expression.

MAIN RESULTS AND THE ROLE OF CHANCE

The median age of participants was 6.3 years, with 65% of them classified as prepubertal by Tanner staging. Approximately 60% of participants had been exposed to chemotherapy and/or radiation prior to OTC. On average 4.7 ± 1 COCs and/or denuded oocytes per participant were recovered from the OTC media. COCs (N = 41) and denuded oocytes (N = 29) were used for IVM (42 h) in a standard or FLI-supplemented maturation medium. The incidence of meiotic maturation was similar between cohorts (COCs: 25.0% vs 28.6% metaphase II arrested eggs in Control vs FLI; denuded oocytes: 0% vs 5.3% in Control vs FLI). However, cumulus cell expansion was 1.9-fold greater in COCs matured in FLI-containing medium relative to Controls and transzonal projection retraction was more pronounced (2.45 ± 0.50 vs 1.16 ± 0.78 projections in Control vs FLIat 16 h). Additionally, MAPK expression was significantly higher in cumulus cells obtained from COCs matured in FLI medium for 16-18 h (chemiluminescence corrected area 621,678 vs 2,019,575 a.u., P = 0.03).

LIMITATIONS, REASONS FOR CAUTION

Our samples are from human participants who exhibited heterogeneity with respect to age, diagnosis, and previous treatment history. Future studies with larger sample sizes, including adult participants, are warranted to determine the mechanism by which FLI induces MAPK expression and activation. Moreover, studies that evaluate the developmental competence of eggs derived from FLI treatment, including assessment of embryos as outcome measures, will be required prior to clinical translation.

WIDER IMPLICATIONS OF THE FINDINGS

FLI supplementation may have a conserved beneficial effect on IVM for children, adolescents, and young adults spanning the agricultural setting to clinical fertility preservation.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Department of Obstetrics and Gynecology startup funds (F.E.D.), Department of Surgery Faculty Practice Plan Grant and the Fertility & Hormone Preservation & Restoration Program at the Ann & Robert H. Lurie Children's Hospital of Chicago (M.M.L. and E.E.R.). M.M.L. is a Gesualdo Foundation Research Scholar. Y.Y.'s research is supported by the internal research funds provided by Colorado Center of Reproductive Medicine. Y.Y., L.D.S., R.M.R., and R.S.P. have a patent pending for FLI. The remaining authors have no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Facilitation of Ovarian Response by Mechanical Force-Latest Insight on Fertility Improvement in Women with Poor Ovarian Response or Primary Ovarian Insufficiency

The decline in fertility in aging women, especially those with poor ovarian response (POR) or primary ovarian insufficiency (POI), is a major concern for modern IVF centers. Fertility treatments have traditionally relied on gonadotropin- and steroid-hormone-based IVF practices, but these methods have limitations, especially for women with aging ovaries. Researchers have been motivated to explore alternative approaches. Ovarian aging is a complicated process, and the deterioration of oocytes, follicular cells, the extracellular matrix (ECM), and the stromal compartment can all contribute to declining fertility. Adjunct interventions that involve the use of hormones, steroids, and cofactors and gamete engineering are two major research areas aimed to improve fertility in aging women. Additionally, mechanical procedures including the In Vitro Activation (IVA) procedure, which combines pharmacological activators and fragmentation of ovarian strips, and the Whole Ovary Laparoscopic Incision (WOLI) procedure that solely relies on mechanical manipulation in vivo have shown promising results in improving follicle growth and fertility in women with POR and POI. Advances in the use of mechanical procedures have brought exciting opportunities to improve fertility outcomes in aging women with POR or POI. While the lack of a comprehensive understanding of the molecular mechanisms that lead to fertility decline in aging women remains a major challenge for further improvement of mechanical-manipulation-based approaches, recent progress has provided a better view of how these procedures promote folliculogenesis in the fibrotic and avascular aging ovaries. In this review, we first provide a brief overview of the potential mechanisms that contribute to ovarian aging in POI and POR patients, followed by a discussion of measures that aim to improve ovarian folliculogenesis in aging women. At last, we discuss the likely mechanisms that contribute to the outcomes of IVA and WOLI procedures and potential future directions.

A 16-year bicentric retrospective analysis of ovarian tissue cryopreservation in pediatric units: indications, results, and outcome

Background

Cancer treatments of the last decades improve the survival rate of children and adolescents. However, chemo- and radiotherapy result in gonadal damage, leading to acute ovarian failure and sterility. The preservation of fertility is now an integral part of care of children requiring gonadotoxic treatments. Ovarian tissue cryopreservation (OTC) is an effective fertility preservation option that allows long-term storage of primordial follicles, subsequent transplantation, and restoration of endocrine function and fertility. The efficacy of this technique is well-demonstrated in adults but the data are scarce for pediatric patients. Currently, OTC represents the only possibility of preserving the potential fertility in prepubertal girls.

Procedure

This is a retrospective study of OTC practice of two French centers from January 2004 to May 2020. A total of 72 patients from pediatric units underwent cryopreservation of ovarian tissue before gonadotoxic therapy for malignant or non-malignant diseases. The ovarian cortex was cut into fragments and the number of follicles per square millimeter was evaluated histologically. The long-term follow-up includes survival rate and hormonal and fertility status.

Results

The mean age of patients at OTC was 9.3 years [0.2-17] and 29.2% were postpubertal; 51 had malignant diseases and 21 had non-malignant diseases. The most frequent diagnoses included acute leukemia, hemoglobinopathies, and neuroblastoma. Indication for OTC was stem cell transplantation for 81.9% (n = 59) of the patients. A third of each ovary was collected for 62.5% (n = 45) of the patients, a whole ovary for 33.3% (n = 24) of the patients, and a third of one ovary for 4.2% (n = 3) of the patients. An average of 17 fragments [5-35] per patient was cryoconserved. A correlation was found between the age of the patients and the number of fragments (p < 0.001). More fragments were obtained from partial bilateral harvesting than from whole ovary harvesting (p < 0.05). Histological analysis of ovarian tissue showed a median of 6.0 primordial follicles/mm2 [0.0-106.5] and no malignant cells were identified. A negative correlation was found between age and follicular density (p < 0.001). Median post-harvest follow-up was 92 months [1-188]. A total of 15 girls had died, 11 were still under treatment for their pathology, and 46 were in complete remission. Of all patients, 29 (40.2%) were subjected to a hormonal status evaluation and 26 were diagnosed with premature ovarian insufficiency (POI) (p < 0.001). One patient had undergone thawed ovarian tissue transplantation.

Conclusion

OTC should be proposed to all girls with high risk of developing POI following gonadotoxic therapies in order to give them the possibility of fertility and endocrine restoration.

A comprehensive review and update on human fertility cryopreservation methods and tools

The broad conceptualization of fertility preservation and restoration has become already a major concern in the modern western world since a large number of individuals often face it in the everyday life. Driven by different health conditions and/or social reasons, a variety of patients currently rely on routinely and non-routinely applied assisted reproductive technologies, and mostly on the possibility to cryopreserve gametes and/or gonadal tissues for expanding their reproductive lifespan. This review embraces the data present in human-focused literature regarding the up-to-date methodologies and tools contemporarily applied in IVF laboratories' clinical setting of the oocyte, sperm, and embryo cryopreservation and explores the latest news and issues related to the optimization of methods used in ovarian and testicular tissue cryopreservation.

Reproductive and Obstetric Outcomes after Fertility-Sparing Treatments for Cervical Cancer: Current Approach and Future Directions

Cervical cancer is one of the leading causes of cancer-related death in women of reproductive age. The established fertility-sparing approaches for the management of early-stage cervical cancer for women who plan pregnancy are associated with a decline in fecundity and an increased risk of pregnancy complications. This article aims to offer an overview of fertility-sparing approaches and the management of potential subfertility and pregnancy complications after these treatments. An extensive search for the available data about infertility and cervical cancer, fertility-sparing techniques in patients with cervical cancer, fertility treatment, obstetrical complications, and pregnancy outcomes in cervical cancer patients was completed. Fertility-preserving procedures such as loop electrosurgical excision procedure (LEEP), cold-knife conization, and trachelectomy in women diagnosed with cervical cancer can be considered as safe and effective treatments that preserve reproductive potential. Current fertility-preserving procedures, based on the balance of the oncological characteristics of patients as well as their desire for reproduction, allow one to obtain acceptable reproductive and obstetric outcomes in women treated for cervical cancer. Nevertheless, careful monitoring of pregnancies obtained after fertility-preserving procedures is recommended, since this cohort of patients should be considered at higher risk compared with a healthy population.