Sodium thiosulfate does not protect ovarian reserve from cisplatin-induced gonadotoxicity†.

Cisplatin, a platinum-containing alkylating agent, is used in the treatment of various tumors owing to its potent antitumor activity. However, it causes permanent and adverse effects, particularly hearing loss and depletion of ovarian reserve. Until recently, there were no clinically available protective agents to mitigate the adverse side effects of cisplatin-induced cytotoxicity. In 2022, sodium thiosulfate (STS) was approved by the Food and Drug Administration for mitigating hearing loss in children and adolescents undergoing cisplatin treatment. Consequently, our investigation aimed to determine if STS could protect ovarian reserve against cisplatin-induced gonadotoxicity. In an ex vivo culture, the cisplatin-only group exhibited a loss of primordial follicles, while post-STS administration after cisplatin exposure effectively protected primordial follicles. However, when post-STS was administrated either 6 or 4 h after cisplatin exposure, it did not confer protection against cisplatin-induced gonadotoxicity in postnatal day 7 or adolescent mouse models. Immunofluorescence assays using γH2AX and cPARP revealed that oocytes within primordial follicles exhibited DNA damage after cisplatin exposure, irrespective of post-STS administration. This underscores the rapid and heightened sensitivity of oocytes to gonadotoxicity. In addition, oocytes demonstrated an increased expression of pCHK2 rather than pERK, suggesting that the pathway leading to oocyte death differs from the pathway observed in the inner ear cell death following cisplatin exposure. These results imply that while the administration of STS after cisplatin is highly beneficial in preventing hearing loss, it does not confer a protective effect on the ovaries in mouse models.

Encapsulated Allografts Preclude Host Sensitization and Promote Ovarian Endocrine Function in Ovariectomized Young Rhesus Monkeys and Sensitized Mice.

Transplantation of allogeneic donor ovarian tissue holds great potential for female cancer survivors who often experience premature ovarian insufficiency. To avoid complications associated with immune suppression and to protect transplanted ovarian allografts from immune-mediated injury, we have developed an immunoisolating hydrogel-based capsule that supports the function of ovarian allografts without triggering an immune response. Encapsulated ovarian allografts implanted in naïve ovariectomized BALB/c mice responded to the circulating gonadotropins and maintained function for 4 months, as evident by regular estrous cycles and the presence of antral follicles in the retrieved grafts. In contrast to non-encapsulated controls, repeated implantations of encapsulated mouse ovarian allografts did not sensitize naïve BALB/c mice, which was confirmed with undetectable levels of alloantibodies. Further, encapsulated allografts implanted in hosts previously sensitized by the implantation of non-encapsulated allografts restored estrous cycles similarly to our results in naïve recipients. Next, we tested the translational potential and efficiency of the immune-isolating capsule in a rhesus monkey model by implanting encapsulated ovarian auto- and allografts in young ovariectomized animals. The encapsulated ovarian grafts survived and restored basal levels of urinary estrone conjugate and pregnanediol 3-glucuronide during the 4- and 5-month observation periods. We demonstrate, for the first time, that encapsulated ovarian allografts functioned for months in young rhesus monkeys and sensitized mice, while the immunoisolating capsule prevented sensitization and protected the allograft from rejection.

Anatomic nomenclature and 3-dimensional regional model of the human ovary: call for a new paradigm.

The ovaries are the female gonads that are crucial for reproduction, steroid production, and overall health. Historically, the ovary was broadly divided into regions defined as the cortex, medulla, and hilum. This current nomenclature lacks specificity and fails to consider the significant anatomic variations in the ovary. Recent technological advances in imaging modalities and high-resolution omic analyses have brought about the need for revision of the existing definitions, which will facilitate the integration of generated data and enable the characterization of organ subanatomy and function at the cellular level. The creation of these high-resolution multimodal maps of the ovary will enhance collaboration and communication among disciplines and between clinicians and researchers. Beginning in March 2021, the Pediatric and Adolescent Gynecology Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development invited subject-matter experts to participate in a series of workshops and meetings to standardize ovarian nomenclature and define the organ's features. The goal was to develop a spatially defined and semantically consistent terminology of the ovary to support collaborative, team science-based endeavors aimed at generating reference atlases of the human ovary. The group recommended a standardized, 3-dimensional description of the ovary and an ontological approach to the subanatomy of the ovary and definition of follicles. This new greater precision in nomenclature and mapping will better reflect the ovary's heterogeneous composition and function, support the standardization of tissue collection, facilitate functional analyses, and enable clinical and research collaborations. The conceptualization process and outcomes of the effort, which spanned the better part of 2021 and early 2022, are introduced in this article. The institute and the workshop participants encourage researchers and clinicians to adopt the new systems in their everyday work to advance the overarching goal of improving human reproductive health.

Evidence of cancer therapy-induced chronic inflammation in the ovary across multiple species: A potential cause of persistent tissue damage and follicle depletion.

Chemotherapy and radiation treatments are known for deleterious effects on the ovary, which can result in prolonged recovery time before ovarian function resumes, including follicular growth after completion of these therapies. To better understand the protracted ovarian dysfunctions after chemotherapy and radiotherapy, we designed a comprehensive study to investigate the underlying mechanisms involved in chronic ovarian damage that prevent follicular development and/or to induce persistent follicle loss. Blood and ovarian samples were collected from reproductive age women, rhesus macaques, and mice after completion of chemotherapy and/or radiotherapy and from age-matched patients and animals without chemotherapy agent or radiation exposure to serve as controls. Serum levels of anti-Müllerian hormone and proinflammatory cytokines, monocyte chemoattractant protein 1 and IL6, were measured. Ovarian tissue was assessed for histopathology and inflammatory cell infiltration, e.g., macrophages and neutrophils, by immuohistochemistry. Serum anti-Müllerian hormone concentrations were lower, whereas proinflammatory cytokine concentrations were higher, in patients and rhesus macaques at ~1 year post-chemotherapy agent and/or radiation exposure compared with controls. The number of primordial follicles reduced in the mouse ovary > 5 weeks after a single injection of cyclophosphamide. Macrophage infiltration was observed in the ovarian cortex of humans and animals. These data suggest that chronic inflammation induced by chemotherapy agents and/or radiation treatment may be associated with persistent ovarian tissue damage, follicle depletion, and functional decline. Interventions that dampen the overactivated inflammatory response may further protect the ovary after completion of chemotherapy and radiotherapy to maintain follicle viability and support continued follicular development in female patients.

Development of sheep secondary follicles and preservation of aromatase and metalloproteinases 2 and 9 after vitrification and in vitro culture.

The cryopreservation of secondary follicles (SF) is a promising alternative to preserve the reproductive potential both in humans and animals in situations in which the transplantation of ovarian tissue is not possible. The objective of the present study was cryopreserved SF isolated sheep. Beyond follicular morphology, viability and development, we investigated proteins related to steroidogenic function and basement membrane remodeling [metalloproteinases 2 (MMP-2) and 9 (MMP-9)] in fresh SF (FSF) and vitrified SF (VSF) followed by in vitro culture for 6 (D6) or 12 days (D12). The percentage of intact follicles, follicular and oocyte diameter of the VSF were lower than FSF on both days of culture (P < 0.05). The VSF viability was statistically reduced from D6 (95.5%) to D12 (77.3%) but did not differ from the FSF on both days (D6:96.2% to D12:86.5%). Antrum formation in the VSF (D6: 59.13%; D12: 79.56%) was significantly lower than the FSF (D6: 79.61%; D12: 92.23%). However, an increase in this percentage was observed from D6 to D12 in both groups. Aromatase showed stronger labeling on FSF D6 and VSF D12 compared to other treatments (P < 0.05). MMP-2 showed a similar pattern of labeling in FSF D6 and VSF D12, similarly to that observed in FSF D12 and VSF D6. MMP-9 was similar in FSF and VSF cultivated for 6 and 12 days. In conclusion, VSF are able to grow and develop during 12 days of in vitro culture and showed evidence of preservation of steroidogenic function and remodeling of the basement membrane.

Oocyte quality following in vitro follicle development†.

In vitro follicle development (IVFD) is an adequate model to obtain basic knowledge of folliculogenesis and provides a tool for ovarian toxicity screening. IVFD yielding competent oocytes may also offer an option for fertility and species preservation. To promote follicle growth and oocyte maturation in vitro, various culture systems are utilized for IVFD in rodents, domestic animals, wild animals, nonhuman primates, and humans. Follicle culture conditions have been improved by optimizing gonadotropin levels, regulatory factors, nutrient supplements, oxygen concentration, and culture matrices. This review summarizes quality assessment of oocytes generated from in vitro-developed antral follicles from the preantral stage, including oocyte epigenetic and genetic profile, cytoplasmic and nuclear maturation, preimplantation embryonic development following in vitro fertilization, as well as pregnancy and live offspring after embryo transfer. The limitations of oocyte quality evaluation following IVFD and the gaps in our knowledge of IVFD to support proper oocyte development are also discussed. The information may advance our understanding of the requirements for IVFD, with a goal of producing competent oocytes with genetic integrity to sustain embryonic development resulting in healthy offspring.

Sphingosine-1-phosphate and its mimetic FTY720 do not protect against radiation-induced ovarian fibrosis in the nonhuman primate†.

Oocytes are highly radiosensitive, so agents that prevent radiation-induced ovarian follicle destruction are important fertility preservation strategies. A previous study in rhesus macaques demonstrated that ovarian treatment with antiapoptotic agents, sphingosine-1-phosphate (S1P) and FTY720, its long-acting mimetic, preserved follicles following a single dose of 15 Gy X-ray radiation, and live offspring were obtained from FTY720-treated animals. However, it is unknown whether these antiapoptotic agents also protected the ovarian stroma from late effects of radiation, including vascular damage and fibrosis. Using ovarian histological sections from this study, we evaluated the vasculature and extracellular matrix in the following cohorts: vehicle + sham irradiation, vehicle + irradiation (OXI), S1P + irradiation (S1P), and FTY720 + irradiation (FTY720). One ovary from each animal was harvested prior to radiation whereas the contralateral ovary was harvested 10 months post-treatment. We assessed vasculature by immunohistochemistry with a PECAM1 antibody, hyaluronan by a hyaluronan binding protein assay, and collagen by picrosirius red and Masson's trichrome staining. Disorganized vessels were observed in the medulla in the OXI and S1P cohorts relative to the sham, but the vasculature in the FTY720 cohort appeared intact, which may partially explain fertoprotection. There were no differences in the hyaluronan matrix among the cohorts, but there was thickening of the tunica albuginea and fibrosis in the OXI cohort relative to the sham, which was not mitigated by either S1P or FTY720 treatment. Thus, the fertoprotective properties of S1P and FTY720 may be limited given their inability to protect the ovarian stroma against the late effects of radiation-induced fibrosis.

Vitrification of caprine secondary and early antral follicles as a perspective to preserve fertility function.

The present study aimed to evaluate the structure, survival and development of isolated caprine (secondary-SEC and early antral-EANT) follicles, after vitrification in the presence of synthetic polymers and in vitro culture. Additionally, transzonal projections (TZPs) and p450 aromatase enzyme were evaluated. After isolation, SEC and EANT follicles were in vitro cultured for six days or vitrified. After one week, SEC and EANT follicles were warmed and also in vitro cultured for six days. Data revealed that the percentage of morphologically normal follicles was similar between fresh and vitrified follicles in both follicular categories and antrum formation rate was similar between fresh and vitrified SEC follicles. Fluorescence by calcein-AM did not show difference between fresh and vitrified (SEC and EANT) follicles, however, the trypan blue test showed low viability for vitrified follicles. The integrity of TZPs was not affected between fresh and vitrified SEC follicles, however, in vitrified EANT follicles, there were signs of TZPs loss. Regarding steroidogenic function, it was observed a positive staining for p450 aromatase enzyme in fresh and vitrified SEC and EANT follicles. It was concluded that SEC follicles seem to be more resistant to vitrification than EANT follicles, as shown by the trypan blue test and TZPs assay. Future studies may confirm this hypothesis, in order to consolidate the use of SEC and EANT follicles as an alternative to ovary cryopreservation.

Impacts of different synthetic polymers on vitrification of ovarian tissue.

Type and concentration of cryoprotective agents (CPAs) are important factors which influence the likelihood of a successful ovarian tissue vitrification outcome. In an attempt to address this factor, the present study was conducted to evaluate the impacts of different synthetic polymers (Supercool X-1000, Supercool Z-1000 and PVP K-12) on vitrification of bovine ovarian tissue. From each ovarian pair, fragments were recovered and immediately fixed for analysis (fresh control) or submitted to vitrification, either or not followed by in vitro culture for one or five days. Vitrification was performed using the ovarian tissue cryosystem (OTC) system. The ovarian tissues were intended for histological and viability analysis [Reactive oxygen species (ROS) production and degenerate cells assay (Ethidium homodimer-1)], as well as immunolocalization of AQP3 and AQP9 were measured. The results showed that during almost all the periods after warming, in treatment groups which contain polymer (X-1000, Z-1000 and PVP), the percentage of morphologically normal follicles was the highest in the X-1000 samples. Furthermore, post-thawed X-1000 group revealed stronger labeling for AQP9 in primordial and transitional follicles, when compared with others. However, morphology after cryopreservation did not correlate with follicle viability and function where the levels of degeneration and tissue damage of PVP K-12 group were lower in comparison with X-1000 group and only in PVP K-12 group, ROS level was similar to that of the fresh control group. We believe that in addition to permeating CPAs, the addition of one (Supercool X-1000) or maybe a combination (Supercool X-1000 and PVP K-12) of non-permeating polymers could be useful to improve the outcome for vitrified bovine ovarian tissue.

A closed vitrification system enables a murine ovarian follicle bank for high-throughput ovotoxicity screening, which identifies endocrine disrupting activity of microcystins.

Increasing evidence reveals that a broad spectrum of environmental chemicals and pharmaceutical compounds cause female ovarian toxicity (ovotoxicity). The current gold standard of ovotoxicity testing largely relies on whole laboratory animals, but in vivo models are time consuming, costly, and present animal welfare concerns. We previously demonstrated that the 3D encapsulated in vitro follicle growth (eIVFG) is a robust in vitro model for ovotoxicity testing. However, the follicle preparation process is complex and highly dependent on technical skills. Here, we aimed to use vitrification method to cryopreserve murine immature follicles for a high-content eIVFG, chemical exposure, and ovotoxicity screening. Results indicated that a closed vitrification system combined with optimized vitrification protocols preserved mouse follicle viability and functionality and vitrified follicles exhibited comparable follicle and oocyte reproductive outcomes to freshly harvested follicles during eIVFG, including follicle survival and development, ovarian steroidogenesis, and oocyte maturation and ovulation. Moreover, vitrified follicles consistently responded to ovotoxic chemical, doxorubicin (DOX). We further used vitrified follicles to test the response of microcystins (MCs), an emerging category of environmental contaminants produced by cyanobacteria associated with harmful algal blooms (HABs), and found that different congeners of MCs exhibited differential ovotoxicities. In summary, our study demonstrates that vitrification enables a long-term-storage and ready-to-use ovarian follicle bank for high-throughput ovotoxicity screening, which identifies endocrine disrupting effects of MCs.

Use of synthetic polymers improves the quality of vitrified caprine preantral follicles in the ovarian tissue.

The aim of this study was to evaluate whether the addition of synthetic polymers to the vitrification solution affected follicular morphology and development and the expression of Ki-67, Aquaporin 3 (AQP3) and cleaved Caspase-3 proteins in ovarian tissue of the caprine species. Caprine ovaries were fragmented and two fragments were immediately fixed (Fresh Control) for morphological evaluation, while other two were in vitro cultured for 7 days (Cultured Control) and fixed as well. The remaining fragments were distributed in two different vitrification groups: Vitrified and Vitrified/Cultured. Each group was composed of 4 different treatments: 1) Sucrose (SUC); 2) SuperCool X-1000 0.2 % (X-1000); 3) SuperCool Z-1000 0.4 % (Z-1000) or 4) with polyvinylpyrrolidone K-12 0.2 % (PVP). Also, Fresh Control, Cultured Control, SUC and X-1000 were destined to immunohistochemical detection of Ki-67, AQP3 and cleaved Caspase-3 proteins. Morphologically, the treatment with X-1000 showed no significant difference with the Fresh Control group and was superior to the other treatments. After the cleaved caspase-3 analysis, X-1000 showed the lowest percentages of strong immunostaining while Cultured Control showed the highest. Also, a positive correlation was found between the percentages of degenerated follicles and the percentages of strong staining intensity follicles. Regarding the AQP3 analysis, the highest percentages of strong AQP3 staining intensity were found in X-1000. In conclusion, we have demonstrated that the addition of the synthetic polymer SuperCool X-1000 to the vitrification solution improved the current vitrification protocol of caprine ovarian tissue.

Can peri-ovulatory putrescine supplementation improve egg quality in older infertile women?

The aging-related decline in fertility is an increasingly pressing medical and economic issue in modern society where women are delaying family building. Increasingly sophisticated, costly, and often increasingly invasive, assisted reproductive clinical protocols and laboratory technologies (ART) have helped many older women achieve their reproductive goals. Current ART procedures have not been able to address the fundamental problem of oocyte aging, the increased rate of egg aneuploidy, and the decline of developmental potential of the eggs. Oocyte maturation, which is triggered by luteinizing hormone (LH) in vivo or by injection of human chorionic gonadotropin (hCG) in an in vitro fertilization (IVF) clinic, is the critical stage at which the majority of egg aneuploidies arise and when much of an egg's developmental potential is established. Our proposed strategy focuses on improving egg quality in older women by restoring a robust oocyte maturation process. We have identified putrescine deficiency as one of the causes of poor egg quality in an aged mouse model. Putrescine is a biogenic polyamine naturally produced in peri-ovulatory ovaries. Peri-ovulatory putrescine supplementation has reduced egg aneuploidy, improved embryo quality, and reduced miscarriage rates in aged mice. In this paper, we review the literature on putrescine, its occurrence and physiology in living organisms, and its unique role in oocyte maturation. Preliminary human data demonstrates that there is a maternal aging-related deficiency in ovarian ornithine decarboxylase (ODC), the enzyme responsible for putrescine production. We argue that peri-ovulatory putrescine supplementation holds great promise as a natural and effective therapy for infertility in women of advanced maternal age, applicable in natural conception and in combination with current ART therapies.

The National Physicians Cooperative: transforming fertility management in the cancer setting and beyond.

Once unimaginable, fertility management is now a nationally established part of cancer care in institutions, from academic centers to community hospitals to private practices. Over the last two decades, advances in medicine and reproductive science have made it possible for men, women and children to be connected with an oncofertility specialist or offered fertility preservation soon after a cancer diagnosis. The Oncofertility Consortium's National Physicians Cooperative is a large-scale effort to engage physicians across disciplines - oncology, urology, obstetrics and gynecology, reproductive endocrinology, and behavioral health - in clinical and research activities to enable significant progress in providing fertility preservation options to children and adults. Here, we review the structure and function of the National Physicians Cooperative and identify next steps.

Inhibition of sperm motility in male macaques with EP055, a potential non-hormonal male contraceptive.

Men have two practical choices for contraception; the condom which has a high typical use failure rate or vasectomy. New male hormonal and non-hormonal contraceptives are under development that target either the production of sperm (spermatogenesis) or the delivery of sperm. One particular target is the sperm protein EPPIN, which is present on the surface of human spermatozoa. EP055 is a small organic compound that targets EPPIN on the surface of sperm and inhibits motility. EP055 was tested in cynomolgus (Macaca fascicularis) males to determine its plasma half-life after intravenous (i.v.) infusion of a single dose and for binding to its target tissues. Our initial study demonstrated a plasma half-life for EP055 of 10.6 minutes. In a second study examination of macaque testis, epididymis, and plasma after i.v. infusion of a single dose of compound EP055 (63.25 mg/kg) demonstrated that EP055 was detected in testis and epididymis two hours and six hours post-infusion. We initiated a trial in rhesus (Macaca mulatta) males to assess the availability of EP055 in semen and its effect on sperm motility as a measure of the drug's efficacy. Four macaques were infused with a low dose (75-80 mg/kg) followed by a recovery period and a subsequent high dose (125-130 mg/kg) of EP055. After high dose administration, sperm motility fell to approximately 20% of pretreatment levels within 6 hours post-infusion; no normal motility was observed at 30 hours post-infusion. Recovery of sperm motility was obvious by 78 hours post-infusion; with full recovery in all animals by 18 days post-infusion. EP055 has the potential to be a male contraceptive that would provide a reversible, short-lived pharmacological alternative.

New Approaches in Cancer Biology Can Inform the Biology Curriculum.

Students tend to be very interested in medical issues that affect them and their friends and family. Using cancer as a hook, the ART of Reproductive Medicine: Oncofertility curriculum (free, online, and NIH sponsored) has been developed to supplement the teaching of basic biological concepts and to connect biology and biomedical research. This approach allows integration of up-to-date information on cancer and cancer treatment, cell division, male and female reproductive anatomy and physiology, cryopreservation, fertility preservation, stem cells, ethics, and epigenetics into an existing biology curriculum. Many of the topics covered in the curriculum relate to other scientific disciplines, such as the latest developments in stem cell research including tissue bioengineering and gene therapy for inherited mitochondrial disease, how epigenetics occurs chemically to affect gene expression or suppression and how it can be passed down through the generations, and the variety of biomedical careers students could pursue. The labs are designed to be open-ended and inquiry-based, and extensions to the experiments are provided so that students can explore questions further. Case studies and ethical dilemmas are provided to encourage thoughtful discussion. In addition, each chapter of the curriculum includes links to scientific papers, additional resources on each topic, and NGSS alignment.

Development of macaque secondary follicles exposed to neutral red prior to 3-dimensional culture.

PURPOSE: Neutral red (NR) may assist identification of preantral follicles in pieces of cortical tissue prior to cryopreservation in cancer patients requesting fertility preservation. This study is the first to analyze this effect by follicle growth rate after long-term culture in primates. METHODS: Ovarian cortex was obtained from adult rhesus macaques, was cut into fragments, and was incubated with NR. Secondary follicles were readily visualized following NR staining and then were encapsulated into alginate beads and cultured individually for 4 weeks in αMEM media supplemented with 10 ng/ml FSH at 5% O2. RESULTS: The survival rates of secondary follicles during culture were similar between those derived from control tissue (71 ± 13%) and those treated with NR (68 ± 9%). The proportion of surviving follicles that formed an antrum were also similar in both groups (70 ± 17% control; 48 ± 24% NR-treated). Follicle diameters were not different between control follicles (184 ± 5µm) and those stained with NR (181 ± 7 µm) on the day of isolation. The percentages of surviving follicles within three cohorts based on their diameters at week 4 of culture were similar between the control group and NR-stained tissue group, fast-grow follicles (24 ± 6% vs. 13 ± 10%), slow-grow follicles (66 ± 5% vs. 60 ± 9%), or no-grow (10 ± 9% vs. 27 ± 6%), respectively. There were no differences in follicle diameters between groups during the culture period. Pre-exposure of secondary follicles to NR diminished their capacity to produce both estradiol and androstenedione by week 4 of culture, when follicles are exhibiting an antrum. Inhibitory effects of NR on steroid production by slow-grow follicles was less pronounced. CONCLUSIONS: NR does not affect secondary follicle survival, growth, and antrum formation during long-term culture, but steroid hormone production by fast-grow follicles is compromised. NR can be used as a non-invasive tool for in situ identification of viable secondary follicles in ovarian cortex before tissue cryopreservation without affecting follicle survival and growth in vitro. Whether maturation or developmental competence of oocytes derived from antral follicles in 3D culture that were previously isolated from NR-stained tissue is normal or compromised remains to be determined. Likewise, the functional consequences of pre-exposure to NR prior to ovarian cortical tissue cryopreservation and transplantation are unknown.

Subcutaneous ovarian tissue transplantation in nonhuman primates: duration of endocrine function and normalcy of subsequent offspring as demonstrated by reproductive competence, oocyte production, and telomere length.

PURPOSE: The main purposes of the study were to investigate the endocrine function of ovarian tissue transplanted to heterotopic subcutaneous sites and the reproductive competence and telomere length of a nonhuman primate originating from transplanted tissue. METHODS: Ovarian cortex pieces were transplanted into the original rhesus macaques in the arm subcutaneously, in the abdomen next to muscles, or in the kidney. Serum estradiol (E2) and progesterone (P4) concentrations were measured weekly for up to 8 years following tissue transplantation. A monkey derived from an oocyte in transplanted ovarian tissue entered time-mated breeding and underwent controlled ovarian stimulation. Pregnancy and offspring were evaluated. Telomere lengths and oocytes obtained following controlled ovarian stimulation were assessed. RESULTS: Monkeys with transplants in the arm and abdomen had cyclic E2 of 100 pg/ml, while an animal with arm transplants had E2 of 50 pg/ml. One monkey with transplants in the abdomen and kidney had ovulatory cycles for 3 years. A monkey derived from an oocyte in transplanted tissue conceived and had a normal gestation until intrapartum fetal demise. She conceived again and delivered a healthy offspring at term. Controlled ovarian stimulations of this monkey yielded mature oocytes comparable to controls. Her telomere length was long relative to controls. CONCLUSIONS: Heterotopic ovarian tissue transplants yielded long-term endocrine function in macaques. A monkey derived from an oocyte in transplanted tissue was reproductively competent. Her telomere length did not show epigenetically induced premature cellular aging. Ovarian tissue transplantation to heterotopic sites for fertility preservation should move forward cautiously, yet optimistically.