Ovarian tissue cryopreservation and novel bioengineering approaches for fertility preservation

Histopathological evaluation of the viability of auto-transplanted ovary following vitrification-thawing process in rabbit as an animal model

Cryopreservation and re-transplantation of ovarian tissue is a relatively new technique to preserve fertility. This study evaluated the preservation of ovarian follicles after the vitrification-thawing procedure by implanting ovarian fragments into the gluteus muscle of rabbit. Bilateral ovariectomy was performed on each rabbit. The cortices were separated from the medullae of ovaries and divided into four fragments. One fresh cortical fragment was used as a control, fixed in 10.00% formalin. Three fragments underwent vitrification-thawing for two weeks. Two of these vitrified-thawed fragments were auto-transplanted into separate locations within the opened gluteus muscle, while the final fragment was fixed in 10.00% formalin. Eight weeks after re-implantation, biopsies were collected from the ovarian fragments and fixed in 10.00% formalin. The numbers and areas (µm2) of morphologically normal follicles were evaluated on sections stained with Hematoxylin and Eosin through light microscopy. The follicular morphology in the ovarian fragments immediately after vitrification-thawing remained similar to that of the fresh ovary. The number of morphologically intact follicles was significantly lower in the ovarian fragments eight weeks after re-implantation than fresh ovary and ovarian tissue fragments after vitrification-thawing procedure. However, follicular development to the antral stage was observed in all samples eight weeks after re-implantation. There was no statistical difference in the areas (µm2) of primordial, primary, pre-antral, and antral follicles in the ovarian fragments before cryopreservation, immediately after vitrification-thawing, and following re-implantation procedures. Auto-transplantation of ovarian tissue into the gluteus muscle of rabbits could be a viable approach for preserving ovarian follicles after vitrification-thawing procedure.

Laparoscopic ovarian tissue collection for fertility preservation in children with malignancies: a multicentric experience

Introduction

Long survivors after childhood cancer are increasing thanks to oncological improvements. Their quality of life and fertility-sparing should be considered in the early phases of each oncological pathway. Cryopreservation of ovarian tissue removed before starting gonadotoxic therapies is the only fertility sparing procedure available for prepubertal children affected by cancer and it does not affect the timing of the start of the treatment.

Materials and methods

The present study shows the surgical and clinical outcomes following laparoscopic ovarian tissue collection (LOTC) for a total of 311 patients aged between 0 and 17 years old from four different European Centers.

Results

Only two major complications were reported according to the Clavien Dindo classification (0.6%).

Discussion

LOTC can be considered a safe procedure.

Current technology and industrialization status of cell-cultivated meat

Interest and investment in cultivated meat are increasing because of the realization that it can effectively supply sufficient food resources and reduce the use of livestock. Nevertheless, accurate information on the specific technologies used for cultivated meat production and the characteristics of cultivated meat is lacking. Authorization for the use of cultivated meat is already underway in the United States, Singapore, and Israel, and other major countries are also expected to approve cultivated meat as food once the details of the intricate process of producing cultivated meat, which encompasses stages such as cell proliferation, differentiation, maturation, and assembly, is thoroughly established. The development and standardization of mass production processes and safety evaluations must precede the industrialization and use of cultivated meat as food. However, the technology for the industrialization of cultivated meat is still in its nascent stage, and the mass production process has not yet been established. The mass production process of cultivated meat may not be easy to disclose because it is related to the interests of several companies or research teams. However, the overall research flow shows that equipment development for mass production and cell acquisition, proliferation, and differentiation, as well as for three-dimensional production supports and bioreactors have not yet been completed. Therefore, additional research on the mass production process and safety of cultivated meat is essential. The consumer's trust in the cultivated meat products and production technologies recently disclosed by some companies should also be analyzed and considered for guiding future developments in this industry. Furthermore, close monitoring by academia and the government will be necessary to identify fraud in the cultivated meat industry.

Novel Approaches Used in Ovarian Tissue Transplantation for Fertility Preservation: Focus on Tissue Engineering Approaches and Angiogenesis Capacity

Due to the impact of the modern lifestyle, female infertility has been reduced because of different reasons. For example, in combined chemotherapeutic therapies, a small fraction of cancer survivors has faced different post-complications and side effects such as infertility. Besides, in modern society, delayed age of childbearing has also affected fertility. Nowadays, ovarian tissue cryopreservation and transplantation (OTC/T) is considered one of the appropriate strategies for the restoration of ovarian tissue and bioactivity in patients with the loss of reproductive function. In this regard, several procedures have been considered to improve the efficacy and safety of OTT. Among them, a surgical approach is used to transplant ovaries into the optimal sites, but the existence of ischemic changes and lack of appropriate revascularization can lead to bulk follicular atresia. Besides, the role of OTC/T is limited in women of advanced maternal age undergoing lifesaving chemo-radiation. As a correlate, the development of de novo approaches with efficacious regenerative outcomes is highly welcomed. Tissue engineering shows high therapeutic potentialities to restore fertility in males and females using the combination of biomaterials, cells, and growth factors. Unfortunately, most synthetic and natural materials are at the experimental stage and only the efficacy has been properly evaluated in limited cases. Along with these descriptions, strategies associated with the induction of angiogenesis in transplanted ovaries can diminish the injuries associated with ischemic changes. In this review, the authors tried to summarize recent techniques, especially tissue engineering approaches for improving ovarian function and fertility by focusing on angiogenesis and neovascularization.

Automatic Evaluation for Bioengineering of Human Artificial Ovary: A Model for Fertility Preservation for Prepubertal Female Patients with a Malignant Tumor

Introduction: The in vitro culture of primordial follicles is the only available option for preserving fertility in prepubertal girls with malignant tumors. The cultivation of primordial follicles in scaffolds as artificial ovaries is a promising approach for this. Methods: Dissociated follicles were placed into an artificial ovarian scaffold composed of fibrinogen and thrombin. The follicles were cultured in a dish dedicated to live cell imaging and observed for growth using immunofluorescence and development via optical microscopy. The morphology of the follicles in the scaffold was three-dimensionally reconstructed using the Imaris software. Growth and development were also quantified. Results: The morphology of artificial ovaries began to degrade over time. Within approximately 7 days, primordial follicles were activated and grew into secondary follicles. A comparison of optical and confocal microscopy results revealed the superior detection of live cells using confocal microscopy. The three-dimensional reconstruction of the confocal microscopy data enabled the automatic enumeration and evaluation of the overall morphology of many follicles. Conclusions: The novel artificial ovary-enabled primordial follicles to enter the growth cycle after activation and grow into secondary follicles. The use of a fibrin scaffold as a carrier preserves the developmental potential of primordial germ cells and is a potentially effective method for preserving fertility in prepubertal girls.

Artificial Ovary for Young Female Breast Cancer Patients

In recent decades, there has been increasing attention toward the quality of life of breast cancer (BC) survivors. Meeting the growing expectations of fertility preservation and the generation of biological offspring remains a great challenge for these patients. Conventional strategies for fertility preservation such as oocyte and embryo cryopreservation are not suitable for prepubertal cancer patients or in patients who need immediate cancer therapy. Ovarian tissue cryopreservation (OTC) before anticancer therapy and autotransplantation is an alternative option for these specific indications but has a risk of retransplantation malignant cells. An emerging strategy to resolve these issues is by constructing an artificial ovary combined with stem cells, which can support follicle proliferation and ensure sex hormone secretion. This promising technique can meet both demands of improving the quality of life and meanwhile fulfilling their expectation of biological offspring without the risk of cancer recurrence.

Fertility preservation in female cancer sufferers: (only) a moral obligation?

PURPOSE

Advances in cancer diagnostics and therapeutics have thankfully led to high numbers of young cancer survivors, although some interventions may sometimes threaten fertility. The authors aimed to assess how evidence-based oncofertility counselling can be adequately fulfilled for the sake of female cancer patients, in light of its complexities and multidisciplinary nature, which require thorough counselling and consent pathways.

MATERIALS AND METHODS

A search has been conducted in the databases PubMed/MEDLINE, Web of Science, Scopus, EMBASE and Google Scholar via search strings such as fertility preservation, reproductive counselling, oncofertility, cancer survivors, in order to identify relevant meaningful sources spanning the 2010-2021 period.

RESULTS

Counselling needs to be implemented in compliance with international guidelines, so as to avoid medicolegal repercussions. Albeit fertility preservation is supported by most health care institutions, actual conditions at health care facilities often reflect several lingering difficulties in the oncofertility process. Oncofertility counselling should foster access to fertility preservation procedures. To best serve that purpose, it should be implemented in a manner consistent with ethical and legal standards, so that patients can make an informed decision based on comprehensive and relevant data.

CONCLUSIONS

Counselling needs to be rooted in a close cooperation of oncologists, reproductive endocrinologists, mental health counsellors and clinical researchers. The provision of oncofertility services is grounded in the moral obligation to uphold individual autonomy, which is essential in a free society, unless the exercise thereof could pose a risk to the children conceived or to others.