Delaying Reproductive Aging by Ovarian Tissue Cryopreservation and Transplantation: Is it Prime Time?

Ovarian tissue cryopreservation and transplantation as a natural means to delay menopause

Ovarian tissue cryopreservation and transplantation (OTCT) offers hope for preserving fertility and endocrine functions in patients undergoing gonadotoxic treatments. Advancements in techniques for the procedure have transformed OTCT from an experimental procedure into a viable option. There is a growing interest in utilizing OTCT to delay menopause and alleviate associated health issues. Menopausal transition affects women globally, leading to symptoms and long- term health risks. OTCT has the potential to restore endocrine functions, reducing menopause-related symptoms while mitigating health consequences such as osteoporosis and cardiovascular diseases. Although the use of OTCT for delaying menopause is not clinically proven, the discussion around shows potential for future utilization. In essence, the remarkable advancements in OTCT have bestowed upon us the ability to safeguard fertility and sustain the delicate endocrine functions of the ovaries. However, it is the tantalizing prospect of utilizing this technique to postpone menopause and alleviate its associated symptoms that truly captivates the imagination. Further research is imperative to substantiate the clinical efficacy of OTCT; nonetheless, its potential in menopausal therapy is both promising and warrants comprehensive exploration. This review highlights advancements and the feasibility of OTCT to postpone menopause as an alternative approach to currently used conventional menopause therapy methods.

Addition of synthetic polymers to a conventional cryoprotectant solution in the vitrification of bovine ovarian tissue

Some synthetic polymers can be used at low concentrations to reduce the toxicity of conventional cryoprotectant agents. In this study we investigated whether the addition of synthetic polymers to a conventional cryoprotectant solution would improve the cryopreservation of bovine ovarian tissue. Freshly collected ovaries from ten adult crossbred cows were incised using a scalpel in the frontal section. From each cow, ovarian cortical slices of 1 mm thickness were divided into 30 fragments of 3 × 3 mm, of which 10 served as fresh controls, 10 were vitrified with conventional cryoprotectant agents (2.93 M glycerol, 27 % w/v; 4.35 M ethylene glycol, 27 % w/v), and 10 were vitrified using the same cryoprotectant agents in addition to synthetic polymers (0.2 % PVP K-12, 0.2 % SuperCool X-1000 ™ w/v and 0.4 % SuperCool Z-1000 ™ w/v). After warming, histology was used to assess follicular quantity and integrity, while in vitro culture of mechanically isolated follicles encapsulated in an alginate matrix was performed for 15 days to assess their growth and hormonal production. Vitrified ovarian tissues presented abnormal morphology, a higher percentage of atretic follicles, and their isolated follicles had lower survival rates and lower frequency of antrum formation during in vitro culture compared to those from fresh tissue. At the end of culture, the follicles that had been cryopreserved produced less estradiol and progesterone than the fresh ones. The addition of synthetic polymers during tissue vitrification did not modify any of these parameters. We conclude that, under the conditions of this study, the use of this combination of synthetic polymers for tissue vitrification did not enhance the preservation of the morphological or functional integrity of bovine ovarian follicles.

Maximizing Success: An Overview of Optimizing the Ovarian Tissue Transplantation Site

Ovarian tissue cryopreservation and transplantation (OTCT) has emerged in recent years as a potential method for reversing abnormal endocrine and reproductive functions, particularly in patients receiving gonadotoxic cancer treatments having longer survival rates. From its first rodent experiments to human trials, OTCT has evolved tremendously, opening new windows for further utilization. Since then, significant progress has been achieved in terms of techniques used for surgical removal of the tissue, optimal fragment size, freezing and thawing procedures, and appropriate surgical sites for the subsequent reimplementation of the graft. In addition, various approaches have been proposed to decrease the risk of ischemic injury, which is the leading cause of significant follicle loss during neo-angiogenesis. This review aims to discuss the pros and cons of ovarian and retroperitoneal transplantation sites, highlighting the justifications for the viability and efficacy of different transplantation sites as well as the potential advantages and drawbacks of retroperitoneal or preperitoneal area.

Transition from pediatrics to adult health care in girls with turner syndrome

INTRODUCTION

Turner Syndrome is a rare condition secondary to a complete or partial loss of one X chromosome, leading to a wide spectrum of clinical manifestations. Short stature, gonadal dysgenesis, cardiovascular malformations, and dysmorphic features characterize its common clinical picture.

AREAS COVERED

The main endocrine challenges in adolescent girls with Turner Syndrome are puberty induction (closely intertwined with growth) and fertility preservation. We discuss the most important clinical aspects that should be faced when planning an appropriate and seamless transition for girls with Turner Syndrome.

EXPERT OPINION

Adolescence is a complex time for girls and boys: the passage to young adulthood is characterized by changes in the social, emotional, and educational environment. Adolescence is the ideal time to encourage the development of independent self-care behaviors and to make the growing girl aware of her health, thus promoting healthy lifestyle behaviors. During adulthood, diet and exercise are of utmost importance to manage some of the common complications that can emerge with aging. All clinicians involved in the multidisciplinary team must consider that transition is more than hormone replacement therapy: transition in a modern Healthcare Provider is a proactive process, shared between pediatric and adult endocrinologists.

Modeling delay of age at natural menopause with planned tissue cryopreservation and autologous transplantation

BACKGROUND

Ovarian tissue cryopreservation has been proven to preserve fertility against gonadotoxic treatments. It has not been clear how this procedure would perform if planned for slowing ovarian aging.

OBJECTIVE

This study aimed to determine the feasibility of cryopreserving ovarian tissue to extend reproductive life span and delay menopause by autotransplantation near menopause.

STUDY DESIGN

Based on the existing biological data on follicle loss rates, a stochastic model of primordial follicle wastage was developed to determine the years of delay in menopause (denoted by D) by ovarian tissue cryopreservation and transplantation near menopause. Our model accounted for (1) age at ovarian tissue harvest (21-40 years), (2) the amount of ovarian cortex harvested, (3) transplantation of harvested tissues in single vs multiple procedures (fractionation), and (4) posttransplant follicle survival (40% [conservative] vs 80% [improved] vs 100% [ideal or hypothetical]).

RESULTS

Our model predicted that, for most women aged <40 years, ovarian tissue cryopreservation and transplantation would result in a significant delay in menopause. The advantage is greater if the follicle loss after transplant can be minimized. As an example, the delay in menopause (D) for a woman with a median ovarian reserve who cryopreserves 25% of her ovarian cortex at the age of 25 years and for whom 40% of follicles survive after transplantation would be approximately 11.8 years, but this extends to 15.5 years if the survival is 80%. As another novel finding, spreading the same amount of tissue to repetitive transplants significantly extends the benefit. For example, for the same 25-year-old woman with a median ovarian reserve, 25% cortex removal, and 40% follicle survival, fractionating the transplants to 3 or 6 procedures would result in the corresponding delay in menopause (D) of 23 or 31 years. The same conditions (3 or 6 procedures) would delay menopause as much as 47 years if posttransplant follicle survival is improved to 80% with modern approaches. An interactive Web tool was created to test all variables and the feasibility of ovarian tissue freezing and transplantation to delay ovarian aging (here).

CONCLUSION

Our model predicts that with harvesting at earlier adult ages and better transplant techniques, a significant menopause postponement and, potentially, fertile life span extension can be achieved by ovarian tissue cryopreservation and transplantation in healthy women.

Current Status and Future Prospects of Stem Cell Therapy for Infertile Patients with Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI), also known as premature menopause or premature ovarian failure, signifies the partial or complete loss of ovarian endocrine function and fertility before 40 years of age. This condition affects approximately 1% of women of childbearing age. Although 5-10% of patients may conceive naturally, conventional infertility treatments, including assisted reproductive technology, often prove ineffective for the majority. For infertile patients with POI, oocyte donation or adoption exist, although a prevalent desire persists among them to have biological children. Stem cells, which are characterized by their undifferentiated nature, self-renewal capability, and potential to differentiate into various cell types, have emerged as promising avenues for treating POI. Stem cell therapy can potentially reverse the diminished ovarian endocrine function and restore fertility. Beyond direct POI therapy, stem cells show promise in supplementary applications such as ovarian tissue cryopreservation and tissue engineering. However, technological and ethical challenges hinder the widespread clinical application of stem cells. This review examines the current landscape of stem cell therapy for POI, underscoring the importance of comprehensive assessments that acknowledge the diversity of cell types and functions. Additionally, this review scrutinizes the limitations and prospects associated with the clinical implementation of stem cell treatments for POI.

High FSH levels impair VEGF secretion of human, frozen-thawed ovarian cortical tissue in vitro

Cryopreservation and reimplantation of human ovarian tissue restore the ovarian hormonal function and fertility due to the preservation of follicles. As the success depends on proper angiogenesis, different approaches aim to support this process. In mice, pretreatment of ovarian tissue with FSH shows increased follicular numbers probably due to the supported angiogenesis by an increased vascular endothelial factor (VEGF) expression. However, in human tissue it remains completely unclear, which effect the hormonal status of the patient has at the time point of reimplantation. Frozen-thawed human ovarian cortical tissue was cultured for 48 h with 0, 1 or 10 ng/mL recombinant human FSH. VEGF-A expression was assessed by ELISA and immunohistofluorescence (IHF) analysis. By IHF, HIF-1α and FSHR expression dependency on culture and FSH concentration was analyzed. Follicles at all stages expressed VEGF-A, which increases during folliculogenesis. Frozen-thawed human ovarian cortical tissue secreted a not statistically different amount of VEGF-A, when cultured in presence of 1 ng/mL FSH (17.5 mIU/mL). However, the presence of 10 ng/mL FSH (175 mIU/mL) significantly decreased VEGF-A expression and secretion. The high FSH concentration increased especially the VEGF-A expression of already growing follicles. The presence of pre-menopausal concentrations of FSH had no significant effect on VEGF-A expression, whereas the presence of elevated FSH levels decreased cortical VEGF-A expression. A hormonal pre-treatment of women with elevated FSH concentrations prior to reimplantation might be considered to support angiogenesis. Here, we show that VEGF-A expression by follicles is affected by FSH dependent on the concentration.

Significance and Influence of Suturing for Ovarian Tissue Transplantation

The purpose of this animal study was to verify the effect of suturing on graft function in ovarian tissue transplantation. Ovaries from 2-week-old rats were transplanted orthotopically into the ovaries of 8-week-old female Wistar rats. The various transplantation methods used were insertion into the ovarian bursa without suturing (group A: control), suturing with a single 6-0 Vicryl stitch (group B: 6-0*1), suturing with a single 10-0 Vicryl stitch (group C: 10-0*1), and suturing with three 10-0 Vicryl stitches (group D: 10-0*3). Two weeks after transplantation, the transplanted ovaries were evaluated histologically and for gene expression. Engraftment rates of the donor ovaries 14 days after transplantation were 62.5%, 100%, 91.7%, and 100% in groups A, B, C, and D, respectively, significantly lower in group A than in the other groups. In terms of gene expression, TNFα levels were significantly higher in group D, and GDF9 and follicle-stimulating hormone receptor (FSHR) levels were significantly lower in group D than in groups A and B. The number of primordial follicles evaluated by HE staining was significantly lower in groups B, C, and D than in group A. Compared to orthotopic transplantation without sutures, direct suturing to the host improved the engraftment rate, although increasing the number of sutures increased inflammatory marker levels and decreased the number of primordial follicles. We believe that it is important to perform ovarian tissue transplantation using optimal suture diameter for good adhesion, but with a minimum number of sutures to preserve ovarian function.

Comparison of orthotopic and heterotopic autologous ovarian tissue transplantation outcomes

OBJECTIVE

To compare the outcomes of orthotopic and heterotopic ovarian tissue transplantation (OTT) techniques.

DESIGN

Mixed prospective-retrospective cohort study.

SETTING

Academic hospital.

PATIENTS

A total of 14 recipients of autologous OTT.

INTERVENTIONS

Of the 14 women, 12 who received orthotopic (n = 6) or heterotopic (n = 6) transplants met the inclusion criteria. All orthotopic transplants and one heterotopic ovarian tissue transplant were performed laparoscopically. Although 5 of the 6 remaining heterotopic transplants were performed subcutaneously under local anesthesia or intravenous sedation, one was performed with robotic assistance. With the exception of one recipient who solely desired restoration of endocrine function, all underwent oocyte retrieval either to cryopreserve oocytes and embryos before the graft function ceased or because they could not otherwise conceive (hysterectomy, radiation damage, and heterotopic transplant).

MAIN OUTCOME MEASURES

Primary outcome measures were graft function and longevity, and the number of embryos generated per retrieval.

RESULTS

The mean age at ovarian tissue harvesting and transplantation was lower in patients with orthotopic vs. heterotopic transplants, although the proportion of transplanted ovarian cortex was lower in heterotopic transplant cases. All grafts restored ovarian endocrine function. Fertilization rates, the number of embryos generated per retrieval, and the mean number of nonarrested embryos were significantly lower in heterotopic OTT. However, time to function and graft longevity were similar between the groups. Although 4 of the 6 women conceived and delivered 7 children among orthotopic ovarian tissue recipients, one recipient had 3 spontaneous live births after heterotopic OTT, presumably because of the induction of function in the remaining menopausal ovary.

CONCLUSIONS

It appears that orthotopic OTT results in higher gamete and embryo quality. However, the endocrine function restoration rate and longevity are similar between the 2 approaches. When feasible, orthotopic OTT should be preferred for those who intend to conceive, although a less invasive heterotopic OTT can be performed for those who primarily desire ovarian endocrine function.

Fertility preservation in pregnant cancer patients after first-trimester abortion: a new challenge with possible solutions

Fertility preservation in pregnant women recently diagnosed with cancer can be a challenge. Raised levels of human chorionic gonadotropin (Beta-hCG) and progesterone in this population of patients may pose a problem for the prompt initiation of controlled ovarian stimulation (COS) due to a potential negative feedback of these hormones on folliculogenesis; however, it is not feasible to wait for negativization of serum beta-hCG levels before starting controlled ovarian stimulation. In literature, very few cases have been reported regarding the preservation of fertility in pregnant women recently diagnosed with cancer. We performed an extended revision of the literature to evaluate the current knowledge of the management of fertility preservation in women with cancer and we examined two cases closely. The first case study involved a cancer patient who underwent surgical abortion at 6.5 weeks of gestation followed by administration of mifepristone to detach any minimal residual trophoblast and consequently to decrease serum beta-hCG and progesterone levels before starting COS. In the second case study, the cancer patient underwent surgical abortion at 7.1 weeks of gestation and simultaneous unilateral oophorectomy for ovarian tissue cryopreservation due to a limited time for COS. By analyzing the results of these studies, it could be hypothesized that mifepristone administration may favor the decrease of serum beta-hCG and progesterone levels in order to permit rapid initiation of COS. In cases where COS is not feasible, ovarian tissue cryopreservation should be considered as an alternative fertility preservation technique.

TurnerFertility trial: fertility preservation in young girls with Turner syndrome by freezing ovarian cortex tissue-a prospective intervention study

OBJECTIVE

To evaluate which girls with Turner syndrome (TS) could benefit from fertility preservation by ovarian tissue cryopreservation on the basis of karyotype, puberty status, and hormonal data.

DESIGN

Prospective intervention study; participants were included between 2018 and 2020.

SETTING

Tertiary hospital in the Netherlands.

PATIENTS

In total, 106 girls with TS aged between 2 and 18 years were included. Girls with minor X chromosome deletions, Y chromosomal content, active infections, or contraindications for surgery were excluded.

INTERVENTION

A laparoscopic unilateral ovariectomy was performed to obtain ovarian cortical tissue for cryopreservation. One tissue fragment per participant was used to determine the number of follicles per ovary by serial sectioning and staining. Chromosome analysis was performed on lymphocytes and buccal cells. A blood sample was taken before the ovariectomy for hormonal analysis.

MAIN OUTCOME MEASURES

The presence of follicles in ovarian cortex tissue from girls with TS in relation to karyotype, puberty status, and hormonal data.

RESULTS

A unilateral ovariectomy was performed on 93 girls with TS. Complications after surgery occurred in 5 girls, including luxation of psychological symptoms in 2 girls. In 13 (14%) girls, a 46,XX cell line was found in buccal cells that was absent in lymphocytes. Follicles were observed in 30 (32%) of the 93 girls and were found mainly in girls with a 46,XX cell line in lymphocytes or buccal cells (Phi coefficient = 0.55). Spontaneous onset of puberty (Phi coefficient = 0.59), antimüllerian hormone (AMH; point-biserial correlation [r] = 0.82), inhibin B (r = 0.67), and follicle-stimulating hormone (r = -0.46) levels were also correlated strongly with the presence of follicles. Furthermore, AMH levels had a significant correlation with the number of follicles per ovary (r = 0.66).

CONCLUSION

Favorable predictive markers for the presence of follicles included either a 46,XX cell line, spontaneous onset of puberty, or a combination of measurable AMH and normal follicle-stimulating hormone levels. Karyotyping of two peripheral cell lines in girls with TS is recommended to reveal hidden mosaicisms. Ovarian tissue cryopreservation should be offered with caution in a research setting to those with a sufficient ovarian reserve, considering the significant loss of follicles after ovarian tissue cryopreservation and autotransplantation. Physicians should pay attention to the mental health of the girls during the whole process.

CLINICAL TRIAL REGISTRATION NUMBER

Trial registration number: NCT03381300- Preservation of Ovarian Cortex Tissue in Girls With Turner Syndrome - Full Text View - ClinicalTrials.gov. Registered on: December 21, 2017. First patient recruited on January 1, 2018.

Adverse effects of ovarian cryopreservation and auto-transplantation on ovarian grafts and quality of produced oocytes in a mouse model

The process of ovarian cryopreservation and transplantation is the only feasible fertility preservation method for prepubertal girls and female patients with cancer who cannot delay radiotherapy and chemotherapy. However, basic research on this technique is lacking. To better understand ovarian function and oocyte quality after ovarian tissue (OT) transplantation, we characterised the appearance, angiogenesis, and endocrine function of ovarian grafts in a murine model; the mitochondrial function and DNA damage in oocytes isolated from the OT; and the development of embryos after in vitro fertilisation. The results showed a decrease in oocyte numbers in the transplanted OT, abnormal endocrine function of ovarian grafts, as well as dysfunctional mitochondria and DNA damage in the oocytes, which could adversely affect subsequent embryonic development. However, these adverse phenotypes were partially or completely resolved within 21 days of transplantation, suggesting that ovulation induction and assisted pregnancy treatment should not be conducted too soon after OT transfer to ensure optimal patient and offspring outcomes.

The Aging Ovary and the Tales Learned Since Fetal Development

BACKGROUND

While the term "aging" implies a process typically associated with later life, the consequences of ovarian aging are evident by the time a woman reaches her forties, and sometimes earlier. This is due to a gradual decline in the quantity and quality of oocytes which occurs over a woman's reproductive lifespan. Indeed, the reproductive potential of the ovary is established even before birth, as the proper formation and assembly of the ovarian germ cell population during fetal life determines the lifetime endowment of oocytes and follicles. In the ovary, sophisticated molecular processes have been identified that regulate the timing of ovarian aging and these are critical to ensuring follicular maintenance.

SUMMARY

The mechanisms thought to contribute to overall aging have been summarized under the term the "hallmarks of aging" and include such processes as DNA damage, mitochondrial dysfunction, telomere attrition, genomic instability, and stem cell exhaustion, among others. Similarly, in the ovary, molecular processes have been identified that regulate the timing of ovarian aging and these are critical to ensuring follicular maintenance. In this review, we outline critical processes involved in ovarian aging, highlight major achievements for treatment of ovarian aging, and discuss ongoing questions and areas of debate.

KEY MESSAGES

Ovarian aging is recognized as what may be a complex process in which age, genetics, environment, and many other factors contribute to the size and depletion of the follicle pool. The putative hallmarks of reproductive aging outlined herein include a diversity of plausible processes contributing to the depletion of the ovarian reserve. More research is needed to clarify if and to what extent these putative regulators do in fact govern follicle and oocyte behavior, and how these signals might be integrated in order to control the overall pattern of ovarian aging.

Ovarian aging in humans: potential strategies for extending reproductive lifespan

Ovarian reserve is a term used to estimate the total number of immature follicles present in the ovaries. Between birth and menopause, there is a progressive decrease in the number of ovarian follicles. Ovarian aging is a continuous physiological phenomenon, with menopause being the clinical mark of the end of ovarian function. Genetics, measured as family history for age at the onset of menopause, is the main determinant. However, physical activity, diet, and lifestyle are important factors that can influence the age of menopause. The low estrogen levels after natural or premature menopause increased the risk for several diseases, resulting in increased mortality risk. Besides that, the decreasing ovarian reserve is associated to reduced fertility. In women with infertility undergoing in vitro fertilization, reduced markers of ovarian reserve, including antral follicular count and anti-Mullerian hormone, are the main indicators of reduced chances of becoming pregnant. Therefore, it becomes clear that the ovarian reserve has a central role in women's life, affecting fertility early in life and overall health later in life. Based on this, the ideal strategy for delaying ovarian aging should have the following characteristics: (1) be initiated in the presence of good ovarian reserve; (2) maintained for a long period; (3) have an action on the dynamics of primordial follicles, controlling the rate of activation and atresia; and (4) safe use in pre-conception, pregnancy, and lactation. In this review, we therefore discuss some of these strategies and its feasibility for preventing a decline in the ovarian reserve.

The Current Strategy in Hormonal and Non-Hormonal Therapies in Menopause—A Comprehensive Review

Menopause is a natural stage of hormonal aging in women, accompanied by a series of symptoms that reduce the quality of life of a fully active person. As no therapy is entirely satisfactory, the race for a better option is in full swing. Our study objective is to investigate the most recent menopause studies on pharmacological resources, emerging therapies, and the particularities of hormonal replacement therapy (HRT). For this purpose, a comprehensive search was conducted in two main databases (PubMed and Web of Science) guided by the specific keywords “menopause” and “therapy” or “estrogen” or “progesterone” or “hormone replacement” during the last ten years period. Studies were eligible if they met certain criteria: randomized controlled trials (RCT) in adult women with menopause and hormonal or non-hormonal therapies. We selected 62 RCTs, which are focused on four main topics: (a) epidemiology of menopause-related symptoms, (b) hormonal replacement therapy (HRT) selective estrogen receptor modulators, (c) emerging therapies, and (d) menopause. HRT has proven a real health benefit for menopausal women; besides, complementary interventions must be considered. Further studies are needed on menopause and menopause-related therapies. The continuous updating of clinical experience will strengthen the therapeutic benefit and the decision to treat patients safely. This goal will fully access all therapeutic resources to address an unresolved health issue of active adult women.

Development of protective agents against ovarian injury caused by chemotherapeutic drugs

BACKGROUND

Chemotherapy is one of the causes of ovarian injury and infertility. Although assisted reproductive technology helps young female patients with cancer become pregnant, preventing chemotherapy-induced ovarian injury will often possess even more significant benefits.

OBJECTIVE

We aimed at demonstrating the hazardous effects and mechanisms of ovarian injury by chemotherapeutic agents, as well as demonstrating agents that protect the ovary from chemotherapy-induced injury.

RESULTS

Chemotherapeutic agents cause death or accelerate activation of follicles and damage to the blood vessels in the ovary, resulting in inflammation. These often require drug development to protect the ovaries from injury.

CONCLUSIONS

Our findings provide a basis for the development of drugs to protect the ovaries from injury. Although there are many preclinical studies on potential protective drugs, there is still an urgent need for a large number of clinical experiments to verify their potential use.

Age-related fertility decline: is there a role for elective ovarian tissue cryopreservation?

Age-related fertility decline (ARFD) is a prevalent concern amongst western cultures due to the increasing age of first-time motherhood. Elective oocyte and embryo cryopreservation remain the most established methods of fertility preservation, providing women the opportunity of reproductive autonomy to preserve their fertility and extend their childbearing years to prevent involuntary childlessness. Whilst ovarian cortex cryopreservation has been used to preserve reproductive potential in women for medical reasons, such as in pre- or peripubertal girls undergoing gonadotoxic chemotherapy, it has not yet been considered in the context of ARFD. As artificial reproductive technology (ART) and surgical methods of fertility preservation continue to evolve, it is a judicious time to review current evidence and consider alternative options for women wishing to delay their fertility. This article critically appraises elective oocyte cryopreservation as an option for women who use it to mitigate the risk of ARFD and introduces the prospect of elective ovarian cortex cryopreservation as an alternative.

Ovarian tissue cryopreservation and transplantation for fertility preservation

Background: As the number of cancer survivors has increased with advancements in cancer treatment, fertility preservation has become a treatment goal. Ovarian tissue cryopreservation (OTC) and transplantation (OTT) has made great progress over the past few decades. It has become the treatment of choice for fertility preservation in adolescents or patients in urgent need of chemotherapy. However, it is considered to be experimental compared with oocyte or embryo cryopreservation in some countries. Nevertheless, OTC and OTT is regarded as the more ideal method for fertility preservation in that it can also restore hormonal functions.Current Concepts: Currently, over 200 live births have been reported worldwide after OTC and OTT, proving the excellence of the technology. However, before its application in clinical settings, some challenges, including cryoinjury, ischemic injury, and cancer cell reimplantation, should be overcome. For cryoinjury, studies are underway on protocol improvement with the addition of agents such as antifreeze protein during cryopreservation. For ischemic injury, various agents have been studied to promote angiogenesis or revascularization. Furthermore, studies are underway on artificial ovary or xenotransplantation for fertility preservation in an effort to avoid cancer cell metastasis.Discussion and Conclusion: OTC and OTT is a clinically applicable option for fertility preservation. To set OTC and OTT as an established method for fertility preservation, further research is necessary to overcome the current challenges.

L-Carnitine improves follicular survival and function in ovarian grafts in the mouse

CONTEXT

Ovarian tissue transplantation is performed to preserve fertility in patients undergoing chemotherapy and radiotherapy. However, the ischemia-reperfusion injury which occurs after the ovarian tissue transplantation causes follicular depletion and apoptosis. l -Carnitine has antioxidant and anti-inflammation properties.

AIMS

Therefore, we aimed to investigate the beneficial effect of l -carnitine on mouse ovaries following heterotopic autotransplantation.

METHODS

Mice were randomly divided into three groups (six mice per group): control, autografted and autografted+l -carnitine (200mg/kg daily intraperitoneal injections). Seven days after ovary autografting, the serum levels of malondialdehyde (MDA), total antioxidant capacity, tumor necrosis factor alpha (TNF-α), interleukin (IL)-6 and IL-10 were measured. Ovary histology, serum concentrations of progesterone and estradiol were also measured 28days after autotransplantation. Data were analysed using one-way analysis of variance (ANOVA) and Tukey test, and the means were considered significantly different at P Key results: In the autografted+l -carnitine group, the total volume of the ovary, the volume of the cortex, the number of follicles, the serum concentrations of IL-10, estradiol and progesterone significantly increased compared to the autografted group. In the autografted+l -carnitine group, serum concentrations of IL-6, TNF-α and MDA were significantly decreased compared to the autografted group.

CONCLUSIONS

Our results indicated that l -carnitine can ameliorate the consequences of ischemia-reperfusion on the mice ovarian tissue following autotransplantation.

IMPLICATIONS

l -carnitine improves the structure and function of transplanted ovaries.

Aging conundrum: A perspective for ovarian aging

Progressive loss of physiological integrity and accumulation of degenerative changes leading to functional impairment and increased susceptibility to diseases are the main features of aging. The ovary, the key organ that maintains female reproductive and endocrine function, enters aging earlier and faster than other organs and has attracted extensive attention from society. Ovarian aging is mainly characterized by the progressive decline in the number and quality of oocytes, the regulatory mechanisms of which have yet to be systematically elucidated. This review discusses the hallmarks of aging to further highlight the main characteristics of ovarian aging and attempt to explore its clinical symptoms and underlying mechanisms. Finally, the intervention strategies related to aging are elaborated, especially the potential role of stem cells and cryopreservation of embryos, oocytes, or ovarian tissue in the delay of ovarian aging.

Effect of Sperm Cryopreservation on miRNA Expression and Early Embryonic Development

Although sperm preservation is a common means of personal fertility preservation, its effects on embryonic development potential need further investigation. The purpose of this study was to identify key microRNA (miRNA) in cryopreserved sperm and determine the changes of these miRNAs and their target genes during embryonic development using cryopreserved sperm. Moreover, the embryonic development potential of cryopreserved sperm was estimated in assisted reproductive technology (ART), where key miRNAs and target genes were validated in sperm and subsequent embryos. Clinical data of embryonic development from cryopreserved sperm indicated a significant decrease in fertilization rate in both in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cases, as well as a reduction in blastocyst formation rate in ICSI cases. Meanwhile there was a significant increase in blocked embryo ratio of Day1, Day2, and Day3.5 embryos when frozen-thawed mouse sperm was used, compared with fresh mouse sperm, suggesting a potential negative effect of sperm cryopreservation on embryonic development. From frozen-thawed and fresh sperm in humans and mice, respectively, 21 and 95 differentially expressed miRNAs (DEmiRs) were detected. miR-148b-3p were downregulated in both human and mouse frozen-thawed sperm and were also decreased in embryos after fertilization using cryopreserved sperm. Target genes of miR-148b-3p, Pten, was identified in mouse embryos using quantitative real-time PCR (qRT-PCR) and Western blot (WB). In addition, common characters of cryopreservation of mouse oocytes compared with sperm were also detected; downregulation of miR-148b-3p was also confirmed in cryopreserved oocytes. In summary, our study suggested that cryopreservation of sperm could change the expression of miRNAs, especially the miR-148b-3p across humans and mice, and may further affect fertilization and embryo development by increasing the expression of Pten. Moreover, downregulation of miR-148b-3p induced by cryopreservation was conserved in mouse gametes.

Maternal Smc3 protects the integrity of the zygotic genome through DNA replication and mitosis

Aneuploidy is frequently observed in oocytes and early embryos, begging the question of how genome integrity is monitored and preserved during this crucial period. SMC3 is a subunit of the cohesin complex that supports genome integrity, but its role in maintaining the genome during this window of mammalian development is unknown. We discovered that, although depletion of Smc3 following meiotic S phase in mouse oocytes allowed accurate meiotic chromosome segregation, adult females were infertile. We provide evidence that DNA lesions accumulated following S phase in SMC3-deficient zygotes, followed by mitosis with lagging chromosomes, elongated spindles, micronuclei, and arrest at the two-cell stage. Remarkably, although centromeric cohesion was defective, the dosage of SMC3 was sufficient to enable embryogenesis in juvenile mutant females. Our findings suggest that, despite previous reports of aneuploidy in early embryos, chromosome missegregation in zygotes halts embryogenesis at the two-cell stage. Smc3 is a maternal gene with essential functions in the repair of spontaneous damage associated with DNA replication and subsequent chromosome segregation in zygotes, making cohesin a key protector of the zygotic genome.

Comparison of open and a novel closed vitrification system with slow freezing for human ovarian tissue cryopreservation

PURPOSE

To investigate the differences concerning post-thawing/warming follicle survival, DNA damage and apoptosis in human ovarian tissues cryopreserved by slow freezing, open, or closed vitrification methods.

METHODS

A total of 50 pieces of 5 × 5 × 1 mm ovarian cortical pieces were harvested (5 donor ovaries; mean age 31 ± 6.62 years). From each donor, one cortical piece was used as baseline; the remaining were randomly assigned to slow freezing (SF), vitrification using open device (VF-open), or closed device (VF-closed) groups. After 8-10 weeks of cryostorage, tissues were evaluated 4 h after thawing/warming. Histological analysis was evaluated for follicle survival (primordial and primary follicle densities) by H&E staining. The percentages of primordial and primary follicles with DNA double-strand breaks (γH2AX) and apoptotic cell death pathway activation (AC3) were immunohistochemically assessed. Data were analysed using one-way ANOVA and LSD post hoc comparison.

RESULTS

Compared to the baseline, primordial follicle (pdf) densities significantly declined in all cryopreserved groups (SF, VF-open, and VF-closed, P < 0.05). However, the total and non-apoptotic pdf densities were similar among SF, VF-open, and VF-closed. SF and VF with either open or closed devices did not increase the percentages of primordial or primary follicles with DNA double-strand breaks (DSBs) or apoptosis compared to the baseline or among the freezing methods in the present study.

CONCLUSION

Based on the intact primordial follicle survival, DNA damage, and apoptosis rates after thawing/warming, SF vs VF with either open or newly developed closed devices appear to be comparable.