Ovary transplantation: to activate or not to activate

Bioengineered 3D Ovarian Models as Paramount Technology for Female Health Management and Reproduction

Ovarian dysfunction poses significant threats to the health of female individuals. Ovarian failure can lead to infertility due to the lack or inefficient production of fertilizable eggs. In addition, the ovary produces hormones, such as estrogen and progesterone, that play crucial roles not only during pregnancy, but also in maintaining cardiovascular, bone, and cognitive health. Decline in estrogen and progesterone production due to ovarian dysfunction can result in menopausal-associated syndromes and lead to conditions, such as osteoporosis, cardiovascular disease, and Alzheimer's disease. Recent advances in the design of bioengineered three-dimensional (3D) ovarian models, such as ovarian organoids or artificial ovaries, have made it possible to mimic aspects of the cellular heterogeneity and functional characteristics of the ovary in vitro. These novel technologies are emerging as valuable tools for studying ovarian physiology and pathology and may provide alternatives for fertility preservation. Moreover, they may have the potential to restore aspects of ovarian function, improving the quality of life of the (aging) female population. This review focuses on the state of the art of 3D ovarian platforms, including the latest advances modeling female reproduction, female physiology, ovarian cancer, and drug screening.

Functional survey of decellularized tissues transplantation for infertile females

Numbers of women worldwide face infertility, which will have a significant impact on a couple's life. As a result, assisting with the treatment of these individuals is seen as a critical step. Successful births following uterus and ovary donation have been reported in recent. When immunosuppressive drugs are used in patients who receive donated tissues, there are always problems with the drugs' side effects. In recent years, tissue engineering has mainly been successful in treating infertility using decellularization techniques. Engineered uterus and ovary prevent immunological reactions and do not require immunosuppressive drugs. The most important aspect of using decellularized tissue is its proper function after transplantation. These tissues must be able to produce follicles, secrete hormones and cause pregnancy. This study aimed to investigate research on decellularized tissues and transplanted into the female reproductive system. In this study, just tissues that, after transplantation, have the proper function for fertility were investigated.

HDAC6 regulates primordial follicle activation through mTOR signaling pathway

Primordial follicle pool established perinatally is a non-renewable resource which determines the female fecundity in mammals. While the majority of primordial follicles in the primordial follicle pool maintain dormant state, only a few of them are activated into growing follicles in adults in each cycle. Excessive activation of the primordial follicles accelerates follicle pool consumption and leads to premature ovarian failure. Although previous studies including ours have emphasized the importance of keeping the balance between primordial follicle activation and dormancy via molecules within the primordial follicles, such as TGF-β, E-Cadherin, mTOR, and AKT through different mechanisms, the homeostasis regulatory mechanisms of primordial follicle activation remain unclear. Here, we reported that HDAC6 acts as a key negative regulator of mTOR in dormant primordial follicles. In the cytoplasm of both oocytes and granulosa cells of primordial follicles, HDAC6 expressed strong, however in those activated primordial follicles, its expression level is relatively weaker. Inhibition or knockdown of HDAC6 significantly promoted the activation of limited primordial follicles while the size of follicle pool was not affected profoundly in vitro. Importantly, the expression level of mTOR in the follicle and the activity of PI3K in the oocyte of the follicle were simultaneously up-regulated after inhibiting of HDAC6. The up-regulated mTOR leads to not only the growth and differentiation of primordial follicles granulosa cells (pfGCs) into granulosa cells (GCs), but the increased secretion of KITL in these somatic cells. As a result, inhibition of HDAC6 awaked the dormant primordial follicles of mice in vitro. In conclusion, HDAC6 may play an indispensable role in balancing the maintenance and activation of primordial follicles through mTOR signaling in mice. These findings shed new lights on uncovering the epigenetic factors involved physiology of sustaining female reproduction.

In vitro activation of cryopreserved ovarian tissue: A single-arm meta-analysis and systematic review

OBJECTIVE

Primordial follicles in premature ovarian failure (POF) patients are very difficult to be activated spontaneously, so that mature oocytes are difficult to be obtained for in vitro fertilization. The aim of our review is to analyze and to systematize the published data regarding effectiveness of different strategies for in vitro activation of cryopreserved ovarian tissue.

STUDY DESIGN

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a review of the literature was performed for all relevant full-text articles published in PubMed in English. Meta-analysis conducted using STATA 14.0. The random-effects model was used to combine 8 study results because the examination of heterogeneity was minimal.

RESULTS

One hundred and seventy seven patients after in vitro activation treatment (IVA) of ovarian tissue had accumulatively 26 pregnancies through IVF or natural pregnancy and then produced 18 live births. The random-effects model showed that the total clinical pregnancy and baby born rates reported in 8 studies evidence about effectiveness of IVA.

CONCLUSION

In vitro activation of primordial follicles as a new potential treatment for ovarian disorder patients, can be a promising option for fertility preservation. Drug-free activation of ovarian tissue in comparison with drug-included activation seemed to be more efficient.

Improvement of in situ Follicular Activation and Early Development in Cryopreserved Human Ovarian Cortical Tissue by Co-Culturing with Mesenchymal Stem Cells

Follicular loss and tissue degeneration are great challenges in ovarian tissue culture systems. Mesenchymal stem cells (MSC) secrete a cocktail of growth factors and cytokines which supports adjacent cells and tissues. The aim of the current study was to investigate the impact of human bone marrow (hBM)-MSC, as co-culture cells, on human follicular development in ovarian cortical tissue (OCT) culture. For this purpose, warmed OCT fragments were co-cultured with hBM-MSC for 8 days and compared to monocultured OCT. During the culture period, ovarian follicle survival and development in the OCT were evaluated using histological observation, follicular developmental-related genes expression, and estradiol production. Furthermore, cell proliferation and apoptosis were assessed. The results showed that there were no significant differences in conserved ovarian follicles with a normal morphology between the two groups. However, the percentage of developing follicles, as well as follicular developmental gene expression, significantly increased in the co-culture group compared to the monoculture group. On the other hand, compared with the monoculture group, the co-culture group demonstrated a significant increase in cell proliferation, indicated by Ki67 gene expression, as well as a dramatic decrease in apoptotic cell percentage, revealed by TUNEL assay. These findings indicated that co-culturing of hBM-MSC with OCT could improve follicular activation and early follicular development in human ovarian tissue culture systems.

HucMSC-Derived Exosomes Mitigate the Age-Related Retardation of Fertility in Female Mice

In mammals, resting primordial follicles serve as the ovarian reserve. The decline in ovarian function with aging is characterized by a gradual decrease in both the quantity and quality of the oocytes residing within the primordial follicles. Many reports show that mesenchymal stem cells have the ability to recover ovarian function in premature ovarian insufficiency (POI) or natural aging animal models; however, the underlying mechanism remains unclear. In this study, using exosomes derived from human umbilical cord mesenchymal stem cells (HucMSC-exos), we found the specific accumulation of exosomes in primordial oocytes. The stimulating effects of exosomes on primordial follicles were manifested as the activation of the oocyte phosphatidylinositol 3-kinase (PI3K)/mTOR signaling pathway and the acceleration of follicular development after kidney capsule transplantation. Further analysis revealed the stimulatory effects of HucMSC-exos on primordial follicles were through carrying functional microRNAs, such as miR-146a-5p or miR-21-5p. In aged female mice, the intrabursal injection of HucMSC-exos demonstrated the recovery of decreased fertility with increased oocyte production and improved oocyte quality. Although assisted reproductive technologies have been widely used to treat infertility, their overall success rates remain low, especially for women in advanced maternal age. We propose HucMSC-exos as a new approach to mitigate the age-related retardation of fertility in women.

In vitro Activation Prior to Transplantation of Human Ovarian Tissue: Is It Truly Effective?

Research Question: What are the true benefits, if any, of disrupting the Hippo signaling pathway and stimulating the Akt pathway in xenotransplanted human ovarian tissue using an in vitro activation (IVA) approach? Design: Human ovarian tissue was retrieved from 18 young patients by laparoscopy and grafted to 54 severe combined immunodeficient mice. The experiment was conducted using fresh ovarian tissue (group I; n = 6 women), slow-frozen-thawed ovarian tissue (group II; n = 6 women), and vitrified-warmed ovarian tissue (group III; n = 6 women). Slow-freezing and vitrification procedures were performed according to Gosden's and Kawamura's protocols, respectively. The tissue (fresh, slow-frozen, and vitrified) was fragmented into small cubes (1 × 1 × 1 mm) to disrupt the Hippo signaling pathway and cultured or not in IVA medium for 48 h with Akt stimulators (PI3K stimulator and PTEN inhibitor), before being transplanted to the mice. All the grafts were maintained for 28 days. Results: (1) Follicular density: Follicular density decreased in all groups after transplantation, most significantly in the vitrification group. Culture with IVA had no impact. (2) Follicle activation: Addition of PI3K stimulator and PTEN inhibitor for 48 h prior to grafting did not significantly change the proportion of primordial follicles in any of the groups (fresh, slow-frozen, or vitrified tissue) compared to 48 h of control culture without these molecules. Particularly, vitrification and culture in IVA medium yielded no benefits in terms of growing follicle percentages or follicle proliferation rates. The large proportion of growing follicles in the vitrified tissue group after grafting may have been responsible for the higher rate of atresia. Conclusion: We were unable to demonstrate any significant benefits of cutting ovarian tissue into small cubes and applying IVA with Akt stimulators. The association of vitrification and transplantation was actually found to be the most deleterious combination with respect to the follicle reserve, and even worse when culture with Akt stimulators was performed.

Fertility preservation options in transgender people: A review

Gender affirming procedures adversely affect the reproductive potential of transgender people. Thus, fertility preservation options should be discussed with all transpeople before medical and surgical transition. In transwomen, semen cryopreservation is typically straightforward and widely available at fertility centers. The optimal number of vials frozen depends on their reproductive goals and treatment options, therefore a consultation with a fertility specialist is optimal. Experimental techniques including spermatogonium stem cells (SSC) and testicular tissue preservation are technologies currently under development in prepubertal individuals but are not yet clinically available. In transmen, embryo and/or oocyte cryopreservation is currently the best option for fertility preservation. Embryo cryopreservation requires fertilization of the transman's oocytes with a donor or partner's sperm prior to cryopreservation, but this limits his future options for fertilizing the eggs with another partner or donor. Oocyte cryopreservation offers transmen the opportunity to preserve their fertility without committing to a male partner or sperm donor at the time of cryopreservation. Both techniques however require at least a two-week treatment course, egg retrieval under sedation and considerable cost. Ovarian tissue cryopreservation is a promising experimental method that may be performed at the same time as gender affirming surgery but is offered in only a limited amount of centers worldwide. In select places, this method may be considered for prepubertal children, adolescents, and adults when ovarian stimulation is not possible. Novel methods such as in-vitro activation of primordial follicles, in vitro maturation of immature oocytes and artificial gametes are under development and may hold promise for the future.

Hippo signaling in the ovary and polycystic ovarian syndrome

PURPOSE

To provide a commentary on our understanding of the role that the Hippo signaling pathway may play in patients with polycystic ovarian syndrome (PCOS) and how this understanding may impact the diagnosis of PCOS.

METHODS

We assessed publications discussing the role of the Hippo signaling pathway in the ovary. In particular, we discuss how Hippo signaling disruption after ovarian fragmentation, combined with treating ovarian fragments with phosphatase and tensin homolog (PTEN) inhibitors and phosphoinositide-3-kinase stimulators to augment AKT signaling, has been used in treatment of patients with primary ovarian insufficiency. Furthermore, we discuss our own data on variations in Hippo signaling pathway gene expression in cumulus cells isolated from women undergoing IVF with a previous diagnosis of PCOS.

RESULTS AND CONCLUSIONS

Aberrant Hippo signaling in PCOS patients is likely a contributing mechanism to the multifactorial etiology of the disease. Given the challenge of discerning the underlying etiology of oligo-ovulation in some patients, especially those with normal body mass indices, and the need for customized stimulation protocols for PCOS patients who have an increased risk of over-response and higher percentage of immature oocyte yield, it is important to identify these patients prior to treatment. Hippo gene expression fingerprints could potentially be used to more accurately define patients with PCOS. Additionally, targeting this pathway with pharmacologic agents could lead to non-surgical therapeutic options for PCOS.

Ovarian manipulation in ART: going beyond physiological standards to provide best clinical outcomes

Current knowledge on ovarian physiology has challenged the traditional concept of folliculogenesis, creating the basis for novel ovarian stimulation protocols in assisted reproduction technology. The purpose of this review was to evaluate the efficacy of novel clinical interventions that could aid clinicians in individualizing their protocols to patients' characteristics and personal situations. We conducted a literature review of the available evidence on new approaches for ovarian stimulation from both retrospective and prospective studies in the PubMed database. Here, we present some of the most important interventions, including follicle growth in the gonadotropin-independent and dependent stage, manipulation of estradiol production throughout ovarian stimulation, control of mid-cycle gonadotropin surges, and luteal phase support after different stimulation protocols and trigger agents. The latest research on IVF has moved physicians away from the classical physiology, allowing the development of new strategies to decouple organ functions from the female reproductive system and challenging the traditional concept of IVF.

Female fertility preservation: past, present and future

Anti-cancer therapy, particularly chemotherapy, damages ovarian follicles and promotes ovarian failure. The only pharmacological means for protecting the ovaries from chemotherapy-induced injury is gonadotrophin-releasing hormone agonist, but its efficiency remains controversial; ovarian transposition is used to shield the ovary from radiation when indicated. Until the late 1990s, the only option for fertility preservation and restoration in women with cancer was embryo cryopreservation. The development of other assisted reproductive technologies such as mature oocyte cryopreservation andin vitromaturation of oocytes has contributed to fertility preservation. Treatment regimens to obtain mature oocytes/embryos have been modified to overcome various limitations of conventional ovarian stimulation protocols. In the last decades, several centres have begun cryopreserving ovarian samples containing primordial follicles from young patients before anti-cancer therapy. The first live birth following implantation of cryopreserved-thawed ovarian tissue was reported in 2004; since then, the number has risen to more than 130. Nowadays, ovarian tissue cryopreservation can be combined within vitromaturation and vitrification of oocytes. The use of cryopreserved oocytes eliminates the risk posed by ovarian implantation of reseeding the cancer. Novel methods for enhancing follicular survival after implantation are presently being studied. In addition, researchers are currently investigating agents for ovarian protection. It is expected that the risk of reimplantation of malignant cells with ovarian grafts will be overcome with the putative development of an artificial ovary and an efficient follicle class- and species-dependentin vitrosystem for culturing primordial follicles.

The Growth of Preantral Follicles and the Impact of Different Supplementations and Circumstances: A Review Study with Focus on Bovine and Human Preantral Follicles

One of the most important concerns cancer survivors face is fertility. Current treatment modalities often result in damage to the reproductive system. Different options have been proposed to preserve the fertility of affected women, and many attempts have been made to improve their chance of childbearing after therapy. Cryopreservation of ovarian tissue and follicles before the onset of cancer treatment and then either transplantation of ovarian tissue or culture of ovarian tissue and individual follicles in vitro is a commonly cited approach. Extensive research is being done to design an optimal condition for the culture of ovarian follicles. Improving follicle culture systems by understanding their actual growth needs might be a crucial step toward fertility preservation in cancer patients. This review article will try to provide a summary of the role of different factors and conditions on growth of human and bovine preantral follicles in vitro.

Transplantation of UC-MSCs on collagen scaffold activates follicles in dormant ovaries of POF patients with long history of infertility

Premature ovarian failure (POF) is a refractory disease for clinical treatment with the goal of restoring fertility. In this study, umbilical cord mesenchymal stem cells on a collagen scaffold (collagen/UC-MSCs) can activate primordial follicles in vitro via phosphorylation of FOXO3a and FOXO1. Transplantation of collagen/UC-MSCs to the ovaries of POF patients rescued overall ovarian function, evidenced by elevated estradiol concentrations, improved follicular development, and increased number of antral follicles. Successful clinical pregnancy was achieved in women with POF after transplantation of collagen/UC-MSCs or UC-MSCs. In summary, collagen/UC-MSC transplantation may provide an effective treatment for POF.

Criopreserved ovarian tissue transplantation and bone restoration metabolism in castrated rats

OBJECTIVES

to evaluate estradiol levels and autotransplantation heated ovarian tissue effects, after vitrification, on rats bone metabolism previously oophorectomized bilaterally.

METHODS

experimental study with 27 rats aged 11 to 12 weeks and weighing 200g to 300g, submitted to bilateral oophorectomy and ovarian tissue cryopreservation for subsequent reimplantation. Animals were divided into two groups, A and B, with 8 and 19 rats, respectively. Autotransplantation occurred in two periods according to castration time: after one week, in group A, and after one month in group B. Serum estradiol measurements and ovary and tibia histological analysis were performed before and after oophorectomy period (early or late) and one month after reimplantation.

RESULTS

in groups A and B, tibia median cortical thickness was 0.463±0.14mm (mean±SD) at the baseline, 0.360±0.14mm after oophorectomy and 0.445±0.17mm one month after reimplantation p<0.005). Trabecular means were 0.050±0.08mm (mean±SD) at baseline, 0.022±0.08mm after oophorectomy and 0.049±0.032mm one month after replantation (p<0.005). There was no statistical difference in estradiol variation between the two study groups (p=0.819).

CONCLUSION

cryopreserved ovarian tissue transplantation restored bone parameters, and these results suggest that ovarian reimplantation in women may have the same beneficial effects on bone metabolism.

Activation of dormant follicles: a new treatment for premature ovarian failure?

PURPOSE OF REVIEW

Premature ovarian failure (POF) is diagnosed by amenorrhea before 40 years of age. Owing to exhaustion of follicles in POF ovaries, egg donation is the only option. Although menstrual cycles cease in POF patients, some of them still contain residual dormant follicles in ovaries. Recently, we developed a new infertility treatment and named it as in-vitro activation (IVA), which enables POF patients to conceive using their own eggs by activation of residual dormant follicles. Here, we summarize data showing the potential of IVA as a new infertility treatment for POF patients.

RECENT FINDINGS

Transgenic mouse studies revealed that the stimulation of phosphatidylinositol-3-kinase-AKT-forkhead box O3 pathway activated dormant primordial follicles. In murine and human ovaries, the phosphatase and tensin homolog inhibitors and phosphatidylinositol-3-kinase activators were demonstrated to activate dormant primordial follicles in in-vitro cultures. Subsequent studies showed that ovarian fragmentation suppressed Hippo signaling pathway, leading to ovarian follicle growth. Combining these two methods in an IVA approach followed by ovarian tissue autotransplantation, successful follicle growth, and pregnancies were reported in POF patients. Currently, two healthy babies were delivered, together with two additional pregnancies.

SUMMARY

IVA treatment is a potential infertility therapy for POF patients who have residual follicles.

Cryopreservation of Ovarian Tissue: Opportunities Beyond Fertility Preservation and a Positive View Into the Future

In current years, ovarian tissue cryopreservation (OTC) and transplantation is gaining ground as a successful method of preserving fertility in young women with primarily cancer diseases, hereby giving them a chance of becoming biological mothers later on. However, OTC preserves more than just the reproductive potential; it restores the ovarian endocrine function and thus the entire female reproductive cycle with natural levels of essential hormones. In a female population with an increased prevalence in the loss of ovarian function due to induced primary ovarian insufficiency (POI) and aging, there is now, a need to develop new treatments and provide new opportunities to utilize the enormous surplus of follicles that most females are born with and overcome major health issues associated with the lack of ovarian hormones. Cell/tissue-based hormone replacement therapy (cHRT) by the use of stored ovarian tissue could be one such option comprising both induction of puberty in prepubertal POI girls, treatment of POI and premature menopause, and as primary prevention at the onset of menopause. In the current review, we explore known and entirely new applications for the potential utilization of OTC including cHRT, social freezing, culture of immature oocytes, and a modern ovarian resection for women with polycystic ovaries, and discuss the indications hereof.

Follicle activation is a significant and immediate cause of follicle loss after ovarian tissue transplantation

PURPOSE

Extensive follicle loss has been demonstrated in ovarian grafts post transplantation, reducing their productivity and lifespan. Several mechanisms for this loss have been proposed, and this study aims to clarify when and how the massive follicle loss associated with transplantation of ovarian tissue graft occurs. An understanding of the mechanisms of follicle loss will pinpoint potential new targets for optimization and improvement of this important fertility preservation technique.

METHODS

Frozen-thawed marmoset (n = 15), bovine (n = 37), and human (n = 46) ovarian cortical tissue strips were transplanted subcutaneously into immunodeficient castrated male mice for 3 or 7 days. Histological (H&E, Masson's trichrome) analysis and immunostaining (Ki-67, GDF9, cleaved caspase-3) were conducted to assess transplantation-associated follicle dynamics, with untransplanted frozen-thawed tissue serving as a negative control.

RESULTS

Evidence of extensive primordial follicle (PMF) activation and loss was observed already 3 days post transplantation in marmoset, bovine, and human tissue grafts, compared to frozen-thawed untransplanted controls (p < 0.001). No significant additional PMF loss was observed 7 days post transplantation. Recovered grafts of all species showed markedly higher rates of proliferative activity and progression from dormant to growing follicles (Ki-67 and GDF9 staining) as well as higher growing/primordial (GF/PMF) ratio (p < 0.02) and higher collagen levels compared with untransplanted controls.

CONCLUSIONS

This multi-species study demonstrates that follicle activation plays an important role in transplantation-induced follicle loss, and that it occurs within a very short time frame after grafting. These results underline the need to prevent this activation at the time of transplantation in order to retain the maximal possible follicle reserve and extend graft lifespan.

Improving oocyte quality by transfer of autologous mitochondria from fully grown oocytes

Older women are often the most challenging group of patients in fertility clinics due to a decline in both number and overall quality of oocytes. The quality of oocytes has been linked to mitochondrial dysfunction. In this mini-review, we discuss this hypothesis and suggest alternative treatment options using autologous mitochondria to potentially augment pregnancy potential in ART. Autologous transfer of mitochondria from the patient's own germline cells has attracted much attention as a possible new treatment to revitalize deficient oocytes. IVF births have been reported after transfer of oogonial precursor cell-derived mitochondria; however, the source and quality of the mitochondria are still unclear. In contrast, fully grown oocytes are loaded with mitochondria which have passed the genetic bottleneck and are likely to be of high quality. An increased supply of such oocytes could potentially be obtained by in vitro follicle activation of ovarian cortical biopsies or from surplus immature oocytes collected from women undergoing ART or fertility preservation of ovarian tissue. Taken together, autologous oocytes are not necessarily a limiting resource in ART as fully grown oocytes with high quality mitochondria can be obtained from natural or stimulated ovaries and potentially be used to improve both quality and quantity of oocytes available for fertility treatment.

Deriving cells expressing markers of female germ cells from premature ovarian failure patient-specific induced pluripotent stem cells

Aim: We proposed a two-step protocol for deriving cells expressing markers of female germ cells (FGCs) from premature ovarian failure patient-specific induced pluripotent stem cells (POF-iPSCs). Material & methods: We cultured POF-iPSCs in suspension and pretreated them with TGFβ-1 (1 ng/ml) for 2 days and continued with both TGFβ-1 and BMP4 (50 ng/ml) for 5 more days. Then changed to media containing retinoic acid (1 μM) and 5% follicular fluid for another 7 days. Expression of markers of different stages of FGCs were detected. Results: c-KIT, STELLA/DPPA3, VASA/DDX4, SCP3, GDF9 and ZP3 were positively detected and statistically significant different when compared with control groups. Conclusion: Our in vitro system was beneficial for POF-iPSCs differentiated cells to express STELLA, VASA and SCP3, which were the markers of meiosis initiation of FGCs.

Xenogeneic Decellularized Scaffold: A Novel Platform for Ovary Regeneration

Women younger than 40 years may face early menopause because of premature ovarian failure (POF). The cause of POF can be idiopathic or iatrogenic, especially the cancer-induced oophorectomy and chemo- or radiation therapy. The current treatments, including hormone replacement therapy (HRT) and cryopreservation techniques, have increased risk of ovarian cancer and may reintroduce malignant cells after autografting. Decellularization technique has been regarded as a novel regenerative medicine strategy for organ replacement, wherein the living cells of an organ are removed, leaving the extracellular matrix (ECM) for cellular seeding. This study aimed to produce a xenogeneic decellularized ovary (D-ovary) scaffold as a platform for ovary regeneration and transplantation. We have developed a novel decellularization protocol for porcine ovary by treatment with physical, chemical, and enzymatic methods. Using hematoxylin and eosin (H&E) staining, DAPI staining, scanning electron microscopy (SEM), and quantitative analysis, this approach proved effective in removing cellular components and preserving ECM. Furthermore, the results of biological safety evaluation demonstrated that the D-ovary tissues were noncytotoxic for rat ovarian cells in vitro and caused only a minimal immunogenic response in vivo. In addition, the D-ovary tissues successfully supported rat granulosa cell penetration ex vivo and showed an improvement in estradiol (E2) hormone secretion.

In Vitro Activation of Follicles and Fresh Tissue Auto-transplantation in Primary Ovarian Insufficiency Patients

CONTEXT

Recently, two patients with primary ovarian insufficiency (POI) delivered healthy babies after in vitro activation (IVA) treatment followed by auto-transplantation of frozen-thawed ovarian tissues.

OBJECTIVE

This study sought to report the first case of live birth after IVA treatment following fresh ovarian tissue grafting in patients with POI, together with monitoring of follicle development and serum hormonal changes.

DESIGN

This was a prospective observational cohort study.

SETTING

We performed IVA treatment in 14 patients with POI with mean age of 29 years, mean duration since last menses of 3.8 years, and average basal FSH level of 94.5 mIU/mL.

INTERVENTIONS

Prior to IVA treatment, all patients received routine hormonal treatments with no follicle development. We removed one ovary from patients with POI and treated them with Akt stimulators. We improved upon early procedures by grafting back fresh tissues using a simplified protocol.

MAIN OUTCOME MEASURES

In six of the 14 patients (43%), a total of 15 follicle development waves were detected, and four patients had successful oocyte retrieval to yield six oocytes. For two patients showing no spontaneous follicle growth, human menopausal gonadotropin treatment induced follicle growth at 6-8 months after grafting. After vitro fertilization of oocyte retrieved, four early embryos were derived. Following embryo transfer, one patient became pregnant and delivered a healthy baby boy, with three other embryos under cryopreservation.

CONCLUSION

IVA technology can effectively activate residual follicles in some patients with POI and allow them to conceive their own genetic offspring. IVA may also be useful for treating patients with ovarian dysfunction including aging women and cancer survivors.

In Vitro Activation: A Dip Into the Primordial Follicle Pool?

CONTEXT

A current limitation of assisted reproduction is the number of available female gametes. This Commentary discusses in vitro activation (IVA), a technique that activates dormant ovarian follicles so that these follicles can become mature oocytes for fertilization. There is considerable evidence that mechanical signaling plays an important role in oocyte maturation and survival; manipulation of the mechanical environment is a key component of the IVA process. IVA acts on existing follicles and does not promote neo-oogenesis, which likely contributes little to the primordial follicle pool in the adult.

CONCLUSIONS

Several women with primary ovarian insufficiency who underwent the IVA procedure have achieved live births. IVA might also be applicable to women with pathological diminished ovarian reserve and those with physiological diminished reserve due to natural aging. Cancer patients with cryopreserved ovarian tissue also might benefit from IVA. Based on future studies, IVA could prove to be a revolutionary tool for assisted reproduction.

In Vitro Activation: A Possible New Frontier for Treatment of Primary Ovarian Insufficiency

In vitro activation (IVA) represents a new frontier in the treatment of women with primary ovarian insufficiency as well as patients with cancer desiring fertility preservation. Here, we review the biological basis of IVA and the recent translation of IVA to humans by targeting Hippo and Akt-signaling pathways. We then provide a new integrated viewpoint on IVA, highlighting basic science research on the aspects of follicular development and ovarian tissue transplantation which may potentially optimize future translational research on IVA. Specific topics discussed include cryopreservation techniques, additional IVA pathway targets, the roles of actin polymerization, paracrine and endocrine factors, and the role of mechanical signaling and associated tissue rigidity in controlling ovarian follicular activation. Further research and improved understanding is needed to optimize success of IVA.