Xenotransplantation of cryopreserved human ovarian tissue into murine back muscle

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.

Bioinformatics identification and validation of biomarkers and infiltrating immune cells in endometriosis

Background

Endometriosis (EM) is a common gynecological disorder that often leads to irregular menstruation and infertility. The pathogenesis of EM remains unclear and delays in diagnosis are common. Thus, it is urgent to explore potential biomarkers and underlying molecular mechanisms for EM diagnosis and therapies.

Methods

Three EM-related datasets (GSE11691, GSE25628, and GSE86534) were downloaded from the Gene Expression Omnibus (GEO) which were integrated into a combined dataset after removing batch effect. Differentially expressed immune cell-related genes were obtained by CIBERSORT, WGCNA, and the identification of differentially expressed genes. Random forest model (RF), support vector machine model (SVM), and generalized linear model (GLM) were then constructed and the biomarkers for EM were determined. A nomogram evaluating the risk of disease was constructed and the validity was assessed by the calibration curve, DCA curve, and clinical impact curve. Single-gene Gene Set Enrichment Analysis (GSEA)was performed to explore the molecular mechanisms of biomarkers. The ceRNA regulatory network of biomarkers was created by Cytoscape and potential target drugs were obtained in the DGIdb database (Drug-Gene Interaction database).The expression levels of biomarkers from clinical samples was quantified by RT-qPCR.

Results

The ratio of eight immune cells was significantly different between the eutopic and ectopic endometrium samples. A total of eight differentially expressed immune cell-related genes were investigated. The SVM model was a relatively suitable model for the prediction of EM and five genes (CXCL12, PDGFRL, AGTR1, PTGER3, and S1PR1) were selected from the model as biomarkers. The calibration curve, DCA curve, and clinical impact curve indicated that the nomogram based on the five biomarkers had a robust ability to predict disease. Single gene GSEA result suggested that all five biomarkers were involved in labyrinthine layer morphogenesis and transmembrane transport-related biological processes in EM. A ceRNA regulatory network containing 184 nodes and 251 edges was constructed. Seven drugs targeting CXCL12, 49 drugs targeting AGTR1, 16 drugs targeting PTGER3, and 21 drugs targeting S1PR1 were extracted as potential drugs for EM therapy. Finally, the expression of PDGFRL and S1PR1 in clinical samples was validated by RT-qPCR, which was consistent with the result of public database.

Conclusions

In summary, we identified five biomarkers (CXCL12, PDGFRL, AGTR1, PTGER3, and S1PR1) and constructed diagnostic model, furthermore predicted the potential therapeutic drugs for EM. Collectively, these findings provide new insights into EM diagnosis and treatment.

Common dysmorphic oocytes and embryos in assisted reproductive technology laboratory in association with gene alternations

Amorphic or defected oocytes and embryos are commonly observed in assisted reproductive technology (ART) laboratories. It is believed that a proper gene expression at each stage of embryo development contributes to the possibility of a decent-quality embryo leading to successful implantation. Many studies reported that several defects in embryo morphology are associated with gene expressions during in vitro fertilization (IVF) treatment. There is lacking literature review on summarizing common morphological defects about gene alternations. In this review, we summarized the current literature. We selected 64 genes that have been reported to be involved in embryo morphological abnormalities in animals and humans, 30 of which were identified in humans and might be the causes of embryonic changes. Five papers focusing on associations of multiple gene expressions and embryo abnormalities using RNA transcriptomes were also included during the search. We have also reviewed our time-lapse image database with over 3000 oocytes/embryos to show morphological defects possibly related to gene alternations reported previously in the literature. This holistic review can better understand the associations between gene alternations and morphological changes. It is also beneficial to select important biomarkers with strong evidence in IVF practice and reveal their potential application in embryo selection. Also, identifying genes may help patients with genetic disorders avoid unnecessary treatments by providing preimplantation genetic testing for monogenic/single gene defects (PGT-M), reduce embryo replacements by less potential, and help scientists develop new methods for oocyte/embryo research in the near future.

Xenograft model of heterotopic transplantation of human ovarian cortical tissue and its clinical relevance

In brief

Xenografts of human ovarian cortical tissue provide a tractable model of heterotopic autotransplantation that is used for fertility preservation in patients undergoing ablative chemo/radiotherapy. This study describes the behavior of hundreds of xenografts to establish a framework for the clinical function of ovarian cortex following autotransplantation over short- and long-term intervals.

Abstract

More than 200 live births have been achieved using autotransplantation of cryopreserved ovarian cortical fragments, yet challenges remain to be addressed. Ischemia of grafted tissue undermines viability and longevity, typically requiring transplantation of multiple cortical pieces; and the dynamics of recruitment within a graft and the influence of parameters like size and patient age at the time of cryopreservation are not well-defined. Here, we describe results from a series of experiments in which we xenografted frozen/thawed human ovarian tissue (n = 440) from 28 girls and women (age range 32 weeks gestational age to 46 years, median 24.3 ± 4.6). Xenografts were recovered across a broad range of intervals (1-52 weeks post-transplantation) and examined histologically to quantify follicle density and distribution. The number of antral follicles in xenografted cortical fragments correlated positively with the total follicle number and was significantly reduced with increased patient age. Within xenografts, follicles were distributed in focal clusters, similar to the native ovary, but the presence of a leading antral follicle coincided with increased proliferation of surrounding follicles. These results underscore the importance of transplanting ovarian tissue with a high density of follicles and elucidate a potential paracrine influence of leading antral follicles on neighboring follicles of earlier stages. This temporal framework for interpreting the kinetics of follicle growth/mobilization may be useful in setting expectations and guiding the parameters of clinical autotransplantation.

Effect of Previous Alkylating Agent Exposure on Follicle Numbers in Cryopreserved Prepubertal and Young Adult Ovarian Tissue after Long-Term Xenografting

Simple Summary

Cryopreservation of ovarian tissue is a promising technique for fertility preservation in cancer patients at increased risk for subfertility. The International Guideline Harmonization Group recommends ovarian tissue cryopreservation for children and young adults before therapy with cumulative doses of alkylating agent at or above 6000–8000 mg/m². A therapy that poses a high risk of subfertility is rarely the first-line therapy and many of the patients have already undergone several regimens of chemotherapy. The aim of our study was to assess the effects of chemotherapy exposures on the quality of cryopreserved ovarian tissue. We confirmed the harmful effects of alkylating agents on xenografted ovarian tissue and suggest that cumulative doses which are not regarded as an indication for fertility preservation in children and young adult may decrease the quality of cryopreserved follicles.

Abstract

Purpose and methods: To elucidate whether previous cancer treatment affects graft recovery and follicle numbers, morphology, and development in grafts, cryopreserved ovarian biopsies obtained from 18 cancer patients aged 1–24 years with and without exposure to chemotherapy were xenografted as 1 mm³ fragments to immunodeficient mice for 22 weeks with exogenous stimulation. Results: Graft recovery showed no association with chemotherapy exposure, pubertal stage, or leukemia contamination. Total follicle number per recovered graft varied between 0 and 1031 in the chemotherapy-exposed and between 0 and 502 in the non-chemotherapy-exposed group. Atretic follicles formed the largest proportion of the follicle pool in chemotherapy-exposed grafts. Increased atresia correlated with exposure to alkylating agents (mean ± SD 8866.2 ± 9316.3 mg/m²) but not with anthracyclines, pubertal stage, or leukemia contamination. Conclusion: The observation confirms the harmful effects of alkylating agents on ovarian tissue. Therapy at the median cumulative dose of 8866 mg/m² leads to the decreased quality of cryopreserved ovarian follicles in children and young adults.

Molecular Mechanism and Prevention Strategy of Chemotherapy- and Radiotherapy-Induced Ovarian Damage

Fertility preservation is an emerging discipline, which is of substantial clinical value in the care of young patients with cancer. Chemotherapy and radiation may induce ovarian damage in prepubertal girls and young women. Although many studies have explored the mechanisms implicated in ovarian toxicity during cancer treatment, its molecular pathophysiology is not fully understood. Chemotherapy may accelerate follicular apoptosis and follicle reservoir utilization and damage the ovarian stroma via multiple molecular reactions. Oxidative stress and the radiosensitivity of oocytes are the main causes of gonadal damage after radiation treatment. Fertility preservation options can be differentiated by patient age, desire for conception, treatment regimen, socioeconomic status, and treatment duration. This review will help highlight the importance of multidisciplinary oncofertility strategies for providing high-quality care to young female cancer patients.

Follicular development and the expression of BAX and vascular endothelial growth factor in transplanted ovaries in uni- and bilateral ovariectomized mice: An experimental study

Background

Several conflicting results have been reported on the survival and function of transplanted ovaries.

Objective

Evaluation of the follicular development and the expression of vascular endothelial growth factor (VEGF) and Bcl-2-associated X protein (BAX) in ovaries transplanted into uni- and bilaterally ovariectomized mice.

Materials and Methods

In this experimental study, 40 female NMRI mice (21-days-old, 12-15 gr) were ovariectomized uni- and bilaterally (n = 20/ group), while the 8-wk-old mice were considered as intact control group (n = 6). 5 weeks after transplantation at the proestrus stage, the morphology of recovered transplanted ovaries and the proportion of follicles were studied at different developmental stages. The apoptosis cell death by pro-apoptotic protein BAX and the expression of VEGF were evaluated using immunohistochemistry.

Results

In the bilaterally ovariectomized mice, among the 455 counted normal follicles, a lower rate of primordial and primary follicles and a higher rate of preantral and antral follicles were observed (p = 0.002). However, the percentages of preantral and antral follicles, and the corpus luteum were significantly lower in the intact control group (among the 508 counted normal follicles in this group) compared to other transplanted groups (p = 0.002). The number of BAX-positive cells in all groups was not significantly different. The VEGF expression was prominent in vessels of the corpus luteum, and also in the theca layer of large follicles of studied groups.

Conclusion

Early discharge of ovarian reserve was prominent in the bilaterally ovariectomized group but the incidence of apoptotic cells and VEGF expression as angiogenic factor did not differ in both ovariectomized mice. Thus, unilaterally ovariectomy has less side effects on the ovarian reserve compared to bilateral ovariectomy.

Hormonal Stimulation of Human Ovarian Xenografts in Mice: Studying Folliculogenesis, Activation, and Oocyte Maturation

Ovarian tissue cryopreservation and banking provides a fertility preservation option for patients who cannot undergo oocyte retrieval; it is quickly becoming a critical component of assisted reproductive technology programs across the world. While the transplantation of cryopreserved ovarian tissue has resulted in over 130 live births, the field has ample room for technological improvements. Specifically, the functional timeline of grafted tissue and each patient's probability of achieving pregnancy is largely unpredictable due to patient-to-patient variability in ovarian reserve, lack of a reliable method for quantifying follicle numbers within tissue fragments, potential risk of reintroduction of cancer cells harbored in ovarian tissues, and an inability to control follicle activation rates. This review focuses on one of the most common physiological techniques used to study human ovarian tissue transplantation, xenotransplantation of human ovarian tissue to mice and endeavors to inform future studies by discussing the elements of the xenotransplantation model, challenges unique to the use of human ovarian tissue, and novel tissue engineering techniques currently under investigation.

Altered expression of activator proteins that control follicle reserve after ovarian tissue cryopreservation/transplantation and primordial follicle loss prevention by rapamycin

PURPOSE

We investigated whether expression of activator proteins that control follicle reserve and growth change after ovarian tissue vitrification and re-transplantation. Moreover, we assessed whether inhibition of mTOR signaling pathway by rapamycin would protect primordial follicle reserve after ovarian tissue freezing/thawing and re-transplantation.

METHODS

Fresh control, frozen/thawed, fresh-transplanted, frozen/thawed and transplanted, rapamycin/control, rapamycin fresh-transplanted, and rapamycin frozen-thawed and transplanted groups were established in rats. After freezing and thawing process, two ovaries were transplanted into the back muscle of the same rat. After 2 weeks, grafts were harvested, fixed, and embedded into paraffin block. Normal and atretic primordial/growing follicle count was performed in all groups. Ovarian tissues were evaluated for the dynamic expressions of Gdf-9, Bmp-15, KitL, Lif, Fgf-2, and p-s6K using immunohistochemistry, and H-score analyses were done.

RESULTS

Primordial follicle reserve reduced almost 50% after ovarian tissue re-transplantation. Expression of Gdf-9 and Lif increased significantly in primordial and growing follicles in frozen-thawed, fresh-transplanted, and frozen/thawed and transplanted groups, whereas expression of Bmp-15, KitL, and Fgf-2 decreased in primordial follicles. Freezing and thawing of ovarian tissue solely significantly increased p-s6K expression in primordial follicles, and on the other hand, suppression of mTORC1 pathway using rapamycin preserved the primordial follicle pool.

CONCLUSION

Altered expressions of activator proteins that regulate primordial follicle reserve and growth may lead to primordial follicle loss and rapamycin treatment can protect ovarian reserve after ovarian tissue cryopreservation/transplantation.

Complete spermatogenesis in intratesticular testis tissue xenotransplants from immature non-human primate

STUDY QUESTION

Can full spermatogenesis be achieved after xenotransplantation of prepubertal primate testis tissue to the mouse, in testis or subcutaneously?

SUMMARY ANSWER

Intratesticular xenotransplantation supported the differentiation of immature germ cells from marmoset (Callithrix jacchus) into spermatids and spermatozoa at 4 and 9 months post-transplantation, while in subcutaneous transplants, spermatogenic arrest was observed at 4 months and none of the transplants survived at 9 months.

WHAT IS KNOWN ALREADY

Auto-transplantation of cryopreserved immature testis tissue (ITT) could be a potential fertility restoration strategy for patients with complete loss of germ cells due to chemo- and/or radiotherapy at a young age. Before ITT transplantation can be used for clinical application, it is a prerequisite to demonstrate the feasibility of the technique and identify the conditions required for establishing spermatogenesis in primate ITT transplants. Although xenotransplantation of ITT from several species has resulted in complete spermatogenesis, in human and marmoset, ITT has not been successful.

STUDY DESIGN, SIZE, DURATION

In this study, we used marmoset as a pre-clinical animal model. ITT was obtained from two 6-month-old co-twin marmosets. A total of 147 testis tissue pieces (~0.8-1.0 mm3 each) were transplanted into the testicular parenchyma (intratesticular; n = 40) or under the dorsal skin (ectopic; n = 107) of 4-week-old immunodeficient Swiss Nu/Nu mice (n = 20). Each mouse received one single marmoset testis tissue piece in each testis and 4-6 pieces subcutaneously. Xenotransplants were retrieved at 4 and 9 months post-transplantation and evaluations were performed with regards to transplant survival, spermatogonial quantity and germ cell differentiation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Transplant survival was histologically evaluated by haematoxylin-periodic acid Schiff (H/PAS) staining. Spermatogonia were identified by MAGE-A4 via immunohistochemistry. Germ cell differentiation was assessed by morphological identification of different germ cell types on H/PAS stained sections. Meiotically active germ cells were identified by BOLL expression. CREM immunohistochemistry was performed to confirm the presence of post-meiotic germ cells and ACROSIN was used to determine the presence of round, elongating and elongated spermatids.

MAIN RESULTS AND THE ROLE OF CHANCE

Four months post-transplantation, 50% of the intratesticular transplants and 21% of the ectopic transplants were recovered (P = 0.019). The number of spermatogonia per tubule did not show any variation. In 33% of the recovered intratesticular transplants, complete spermatogenesis was established. Overall, 78% of the intratesticular transplants showed post-meiotic differentiation (round spermatids, elongating/elongated spermatids and spermatozoa). However, during the same period, spermatocytes (early meiotic germ cells) were the most advanced germ cell type present in the ectopic transplants. Nine months post-transplantation, 50% of the intratesticular transplants survived, whilst none of the ectopic transplants was recovered (P < 0.0001). Transplants contained more spermatogonia per tubule (P = 0.018) than at 4 months. Complete spermatogenesis was observed in all recovered transplants (100%), indicating a progressive spermatogenic development in intratesticular transplants between the two time-points. Nine months post-transplantation, transplants contained more seminiferous tubules with post-meiotic germ cells (37 vs. 5%; P < 0.001) and fewer tubules without germ cells (2 vs. 8%; P = 0.014) compared to 4 months post-transplantation.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Although xenotransplantation of marmoset ITT was successful, it does not fully reflect all aspects of a future clinical setting. Furthermore, due to ethical restrictions, we were not able to prove the functionality of the spermatozoa produced in the marmoset transplants.

WIDER IMPLICATIONS OF THE FINDINGS

In this pre-clinical study, we demonstrated that testicular parenchyma provides the required microenvironment for germ cell differentiation and long-term survival of immature marmoset testis tissue, likely due to the favourable temperature regulation, growth factors and hormonal support. These results encourage the design of new experiments on human ITT xenotransplantation and show that intratesticular transplantation is likely to be superior to ectopic transplantation for fertility restoration following gonadotoxic treatment in childhood.

STUDY FUNDING/COMPETING INTEREST(S)

This project was funded by the ITN Marie Curie Programme 'Growsperm' (EU-FP7-PEOPLE-2013-ITN 603568) and the scientific Fund Willy Gepts from the UZ Brussel (ADSI677). D.V.S. is a post-doctoral fellow of the Fonds Wetenschappelijk Onderzoek (FWO; 12M2815N). No conflict of interest is declared.

Investigation on revascularization time and initial damage after transplantation of fresh and cryopreserved ovarian tissue in domestic cats

The present study evaluated revascularization time of fresh and cryopreserved cat ovarian tissue after transplantation to subcutaneous tissue. Ovaries of five cats were used and eight pieces of ovarian tissue were taken from each pair of ovaries. Immediately after removal, three pieces were transplanted and one fixed for fresh control. The remaining four pieces were cryopreserved and, after thawing, one was fixed for cryopreservation control and three were transplanted. Grafts were recovered on days 2 (D2), 4 (D4) and 6 (D6) post-transplantation. Blood vessels were identified by immunohistochemistry and doppler ultrasound. Immunohistochemistry showed that the percentages of total tissue area occupied by blood vessels were similar (P > 0.05) in fresh and cryopreserved tissues. In both cases, blood vessel area was significantly higher (P < 0.05) on D4 and D6 compared to D0. Ultrasound analysis showed vascularization improvement on the periphery of grafts from D2 to D4 and from D4 to D6, both in fresh and cryopreserved tissue samples. Nonetheless, there was a significant decrease (P < 0.05) in the percentage of morphologically normal follicles (MNF) after transplantation compared to non-transplanted tissue (D0), both for fresh and cryopreserved samples. Moreover, the number of follicles found in samples was considerably smaller after grafting. In conclusion, revascularization of ovarian tissue autotransplanted to subcutaneous tissue in domestic cats occurs within 4 days after transplantation, both for fresh and cryopreserved tissue. However, large follicular loss has been observed in the first days post-transplantation, especially in cryopreserved tissues.

Randomized study to prove the quality of human ovarian tissue cryopreservation by xenotransplantation into mice

Purpose

To study the quality of our human ovarian tissue cryopreservation technique as performed in the first official "International Fertility Protection Centre" in China in patients with certain cancer types using a mouse model, and to find the best site for tissue transplantation in the mouse.

Methods

Thirty-six BALB/C female nude mice were randomly divided into 3 groups, group 1: control group; group 2: ovariectomized group; group 3: ovarian tissue transplantation group. Seventy-two pieces obtained from six ovarian tissue samples from each of three cancer patients were transplanted into the ovarian bursa cavity (OBC), the subcutaneous thigh (TS) and the subcutaneous neck (NS) and removed after 1.5 and 2.5 months, respectively. Follicular growth rate (FGR), total follicle surviving rate (TFSR), tissue recovery rate (TRR), antral follicles (AF), follicle stimulating hormone (FSH), estradiol (E2) and anti-Mullerian hormone (AMH) levels were measured.

Results

No significant differences in FGR, OBC, NS (p > 0.05); TFSR was 100% in OBC, NS and TS. No significant differences in TRR (p > 0.05); AF were found only in OBC; TFSR was 100% after transplantation; significantly higher FGR in the 2.5 months compared to the 1.5 months-group (p  < 0.05). AMH- and E2-level in group 1 and 3 were significantly higher than in group 2 (p < 0.05); in contrast, FSH was significantly lower.

Conclusions

After transplantation in the mice, the thawed ovarian tissue survived and follicles developed. The ovarian fossa site was the best site for transplantation. Our animal experiments can verify that our human ovarian tissue cryopreservation technique can preserve the quality of ovarian tissue. This is the essential precondition for successful re-transplantation into the patients after performing chemo/radiotherapy to protect ovarian function and fertility.

Recent advances in oncofertility care worldwide and in Japan

BACKGROUND

Oncofertility is a crucial facet of cancer supportive care. The publication of guidelines for the cryopreservation of oocytes and ovarian tissue is becoming increasingly prevalent in Japan and an updated overview is necessary.

METHODS

In order to provide an updated overview of oncofertility care, original research and review articles were searched from the PubMed database and compared in order to present clinical care in Japan.

RESULTS

In Western countries, various methods for ovarian stimulation, such as the combined use of aromatase inhibitors and random-start protocols, have been reported. Although ovarian tissue cryopreservation, mainly performed via the slow-freezing method, also has yielded >100 live births, the optimal indications and procedures for the auto-transplantation of cryopreserved tissue have been under investigation. In Japan, however, vitrification is prevalent for ovarian tissue cryopreservation, although its efficacy has not yet been established. The quality of network systems for providing oncofertility care in Japan varies greatly, based on the region.

CONCLUSION

There remain many issues in the optimization of oncofertility care in Japan. Along with the regional oncofertility networks, the creation of "oncofertility navigators" from healthcare providers who are familiar with oncofertility, such as nurses, psychologists, and embryologists, could be useful for supplementing oncofertility care coordination, overcoming the issues in individual regions.

Wistar rats immature testicular tissue vitrification and heterotopic grafting

Objective

To evaluate the efficiency of two vitrification protocols for rat immature testicular tissue and heterotopic transplantation.

Methods

Twenty-four pre-pubertal Wistar rats were divided into three groups (n=8). After orchiectomy, testicular fragments (3mm) from Groups 1 and 2 were vitrified with different cryoprotectant concentration solutions, using sterile inoculation loops as support. After warming up, the fragments were submitted to cell viability assessment by Trypan blue and histological evaluation. Vitrified (Groups 1 and 2) and fresh (Group 3) fragments were grafted to the animals periauricular region. After 8 weeks of grafting, the implant site was histologically analyzed.

Results

The viability recovery rate from Group 1 (72.09%) was higher (p=0.02) than that from Group 2 (59.19%). Histological analysis showed similar tubular integrity between fresh fragments from Groups 1 and 3. Group 2 samples presented lower tubular integrity. We ran histological analyses in the grafts from the Groups. In all groups, it was possible to see the implant site, however, no fragment of testicular tissue or signs of inflammation were histologically found in most samples from Groups 1 and 3. In one sample from Group 2, we found degenerated seminiferous tubules with necrosis and signs of an inflammatory process. In another sample from Group 2, we found seminiferous tubules in the implant site.

Conclusion

The vitrification of pre-pubertal testicular tissue of rats showed little damage to cell viability through histological analysis when we used cryoprotectants in a lower concentration. Heterotopic transplantation could not preserve the structural organization of the testicular tissue.

Repetitive Maturation of Oocytes From Non-Stimulated Xenografted Ovarian Tissue From a Prepubertal Patient Indicating the Independence of Human Ovarian Tissue

Introduction

Modern anti-cancer strategies have distinctly increased survival rates; nevertheless, often accompanied by sterility. Currently, the only option for preserving fertility in prepubertal females is to cryopreserve ovarian tissue and re-transplant frozen-thawed tissue to restore fertility after treatment. Our aim was to report the occurrence of repetitive antral follicle formation and oocyte maturation in a prepubescent ovarian tissue xenograft without exogenous hormone stimulation.

Material and Methods

Frozen-thawed ovarian tissue from a 6-year-old patient suffering from nephroblastoma was xenotransplanted in oophorectomized severe combined immunodeficiency (SCID) mice to evaluate follicle development.

Ergebnisse

Repetitive follicle development to the antral stage occurred in the same xenograft of prepubertal ovarian tissue without exogenous hormone administration; 37 days after retrieving a maturing oocyte (this first retrieval has been previously published), another, completely mature oocyte was harvested from the xenograft. Subsequent histological evaluation of the grafted tissue showed primordial follicles, nearly all stages of developing follicles, as well as large atretic ones. Many clusters with dormant primordial follicles were also present.

Conclusion

Xenotransplanted prepubertal ovarian tissue has the potential for repetitive oocyte retrieval cycles without administering exogenous hormones. The results indicate that the human ovarian tissue might be able to synchronize the hypothalamus-hypophysis-axes of the mouse to the physiological human cycle; this should be investigated in future studies.

Comparison of Allotransplantation of Fresh and Vitrified Mouse Ovaries to The Testicular Tissue under Influence of The Static Magnetic Field

Objective

The aim of this study was to investigate the effects of static magnetic field (SMF) during transplantation of the ovarian tissue into the testis.

Materials and Methods

In this experimental study, ovaries of 6- to 8-week-old female Naval Medical Research Institute (NMRI) mice were randomly divided into four groups: i. Fresh ovaries were immediately transplanted into the testicular tissue (FOT group), ii. Fresh ovaries were exposed to the SMF for 10 minutes and then transplanted into the testicular tissue (FOT+group), iii. Vitrified-warmed ovaries were transplanted into the testicular tissue (VOT group), and iv. Vitrified-warmed ovaries were transplanted into the testicular tissue and the transplantation site was then exposed to the SMF for 10 minutes (VOT+group).

Results

The lowest percentages of morphologically dead primordial follicles and the highest percentages of morphologically intact primordial follicles were seen in the FOT+ group (4.11% ± 2.88 and 41.26% ± 0.54, respectively). Although the lowest significant percentage of maturation, embryonic development and fertility was observed in the VOT group as compared to the other groups, the difference in the fertility rate was not significant between the VOT and VOT+groups. Estrogen and progesterone concentrations were significantly higher in the FOT+group than those of the control mice.

Conclusion

It is concluded that, exposure of the vitrified-warmed ovaries to SMF retains the structure of the graft similar to that of fresh ovaries.

Human umbilical cord stem cell conditioned medium versus serum-free culture medium in the treatment of cryopreserved human ovarian tissues in in-vitro culture: a randomized controlled trial

BACKGROUND

To reduce young female fertility loss, the in-vitro culture of cryopreserved ovarian cortical tissues (OCTs) is considered an effective approach without delaying treatment and undergoing stimulation medicine. However, ischemic damage and follicular loss during the in-vitro culture of OCTs are major technical challenges. Human umbilical cord stem cells (HUMSCs) and their conditioned medium (HUMSC-CM) have been considered to be potential resources for regeneration medicine because they secrete cytokines and enhance cell survival and function. The aim of this study was to determine whether HUMSC-CM improves the development of frozen-thawed in-vitro cultured ovarian tissues compared with a serum-free culture medium (SF-CM).

METHODS

The thawed OCTs (n = 68) were cultivated in HUMSC-CM and SF-CM in vitro for 8 days, and the ovarian tissues were processed and analyzed by a classical histological evaluation. The microvessel density (MVD) and apotosis detection during in-vitro culture of OCTs were also performed.

RESULTS

A significant difference in the rate of morphologically normal primordial follicles in the HUMSC-CM group was observed compared to that in the SF-CM group (group C) from days 2 to 4 (day 2: group B 58.0 ± 2.45% vs group C 32.0 ± 5.83%, p = 0.002; day 3: group B 55.5 ± 4.20% vs group C 21.0 ± 9.80%, p = 0.048; day 4: group B 52.0 ± 4.08% vs group C 21.5 ± 8.19%, p = 0.019). The microvessel density (MVD) detection showed a time-dependent increase and peaked on day 4. There was a significant difference between groups B (49.33 ± 0.58) and C (24.33 ± 3.79) (p = 0.036). The percentage of apoptotic follicles in group B was lower than that in group C on day 1 (13.75 ± 2.50% vs 27.0 ± 10.10%, p = 0.003), day 5 (11.75 ± 1.50% vs 51.0 ± 10.5%, p = 0.019) and day 7 (15.0 ± 5.10% vs 46.5 ± 21.75%, p = 0.018).

CONCLUSIONS

These data have provided the first experimental evidence of the effect of HUMSC-CM on frozen-thawed OCTs in vitro. The results showed that the HUMSC-CM group provided a better protecting effect on the in-vitro culture of the cryopreserved OCTs compared to the SF-CM group.

Fertility preservation through gonadal cryopreservation

Fertility preservation is an area of immense interest in today's society. The most effective and established means of fertility preservation is cryopreservation of gametes (sperm and oocytes) and embryos. Gonadal cryopreservation is yet another means for fertility preservation, especially if the gonadal function is threatened by premature menopause, gonadotoxic cancer treatment, surgical castration, or diseases. It can also aid in the preservation of germplasm of animals that die before attaining sexual maturity. This is especially of significance for valuable, rare, and endangered animals whose population is affected by high neonatal/juvenile mortality because of diseases, poor management practices, or inbreeding depression. Establishing genome resource banks to conserve the genetic status of wild animals will provide a critical interface between ex-situ and in-situ conservation strategies. Cryopreservation of gonads effectively lengthens the genetic lifespan of individuals in a breeding program even after their death and contributes towards germplasm conservation of prized animals. Although the studies on domestic animals are quite promising, there are limitations for developing cryopreservation strategies in wild animals. In this review, we discuss different options for gonadal tissue cryopreservation with respect to humans and to laboratory, domestic, and wild animals. This review also covers recent developments in gonadal tissue cryopreservation and transplantation, providing a systematic view and the advances in the field with the possibility for its application in fertility preservation and for the conservation of germplasm in domestic and wild species.

Restoration of ovarian tissue function and estrous cycle in rat after autotransplantation using hyaluronic acid hydrogel scaffold containing VEGF and bFGF

This study investigates the effect of hyaluronic acid (HA) containing VEGF and bFGF on restoration of ovarian function after ovarian autotransplantation. Twenty-four rats were randomly divided into three groups for ovarian autotransplantation: group A (ovaries without HA, VEGF and bFGF), group B (ovaries encapsulated with HA) and group C (ovaries encapsulated with HA containing VEGF and bFGF). The grafts were assessed using vaginal smears, histological, hormonal, and the genes expression analysis. The duration of first estrous cycle was shorter in group C than in group A (p < 0.01). The mean number of primordial follicles was protected in group C. The level of estradiol was higher in group A than in group C (p < 0.01). The expression level of Cellular-Myelocytomatosis (C-Myc) in group C was lower than in group B (p < 0.05). HA containing VEGF and bFGF can ensure follicular survival, decrease apoptosis and recover ovarian function after auto-transplantation.

Xenotransplantation of cryopreserved human ovarian tissue--a systematic review of MII oocyte maturation and discussion of it as a realistic option for restoring fertility after cancer treatment

OBJECTIVE

To systematically review the reporting of MII (MII) oocyte development after xenotransplantation of human ovarian tissue.

DESIGN

Systematic review in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA).

SETTING

Not applicable.

PATIENT(S)

Not applicable.

INTERVENTION(S)

Formation of MII oocytes after xenotransplantation of human ovarian tissue.

MAIN OUTCOME MEASURE(S)

Any outcome reported in Pubmed.

RESULT(S)

Six publications were identified that report on formation of MII oocytes after xenotransplantation of human ovarian tissue.

CONCLUSION(S)

Xenografting of human ovarian tissue has proved to be a useful model for examining ovarian function and follicle development in vivo. With human follicles that have matured through xenografting, the possibility of cancer transmission and relapse can also be eliminated, because cancer cells are not able to penetrate the zona pellucida. The reported studies have demonstrated that xenografted ovarian tissue from a range of species, including humans, can produce antral follicles that contain mature (MII) oocytes, and it has been shown that mice oocytes have the potential to give rise to live young. Although some ethical questions remain unresolved, xenotransplantation may be a promising method for restoring fertility. This review furthermore describes the value of xenotransplantation as a tool in reproductive biology and discusses the ethical and potential safety issues regarding ovarian tissue xenotransplantation as a means of recovering fertility.

Assessment of vitrification outcome by xenotransplantation of ovarian cortex pieces in γ-irradiated mice: morphological and molecular analyses of apoptosis

PURPOSE

The aim of this study was the investigation of caspase-3/7 activity and apoptosis related gene expression after vitrification and xenotransplantation of human ovarian fragments.

METHODS

Ovarian specimens were obtained from normal female-to-male transsexual women during laparoscopic surgery and cut into small pieces and were considered as vitrified and non-vitrified groups. The morphological study, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, caspase-3/7 activity and apoptosis related gene expression analysis were done in both non-vitrified and vitrified groups in two steps (before transplantation of ovarian tissues and 30 days after transplantation).

RESULT(S)

In spite of high rate of normal follicles in both non-transplanted tissues these rates were significantly decreased in vitrified and non-vitrified grafted tissues, moreover grafted-vitrified tissue showed significantly less normal follicles than grafted-non-vitrified group (P < 0.05). The expression of some pro and anti-apoptotic genes in vitrified-warmed tissues were not changed compared to non-vitrified ones but the expression of Fas and caspase8 was increased and the expression of BRIC5 was decreased in this group (P < 0.05). In transplanted vitrified group the Bcl2, FasL and BRIC5 gene expression was high and caspase8 was low (P < 0.05). The expression of all genes in both grafted groups was more than non-grafted tissues except for caspase8 (P < 0.05). The TUNEL positive signals and caspase-3/7 activity were increased in both grafted groups compared to non-grafted groups and this enzyme activity in grafted-vitrified group was more than grafted-non-vitrified group (P < 0.05).

CONCLUSION(S)

This study provides the first evidence on the significant effect of vitrification on follicular apoptosis of grafted human ovarian tissue at mRNA level. The signs of follicular survival or degeneration detected by morphological assessment and caspase-3/7 activity were closely correlated to the changes in expression of apoptosis-related genes.

Mesenchymal Stem Cells Enhance Angiogenesis and Follicle Survival in Human Cryopreserved Ovarian Cortex Transplantation

Transplantation of cryopreserved ovarian tissue is a novel technique to restore endocrine function and fertility especially for cancer patients. However, the main obstacle of the technique is massive follicle loss as a result of ischemia in the process of transplantation. Mesenchymal stem cells (MSCs) have been acknowledged to play an important role in supporting angiogenesis and stabilizing long-lasting blood vessel networks through release of angiogenic factors and differentiation into pericytes and endothelial cells. This study is aimed to investigate whether MSCs could be applied to overcome the above obstacle to support the ovarian tissue survival in the transplantation. Here we show that human MSCs could enhance the expression level of VEGF, FGF2, and especially the level of angiogenin, significantly stimulate neovascularization, and increase blood perfusion of the grafts in the cryopreserved ovarian tissue transplantation. Further studies reveal that MSCs could notably reduce the apoptotic rates of primordial follicles and decrease follicle loss in the grafted ovarian tissues. In summary, our findings demonstrate a previously unrecognized function of MSCs in improving human ovarian tissue transplantation and provide a useful strategy to optimize fertility preservation and restoration.

Follicles of various maturation stages react differently to enzymatic isolation: a comparison of different isolation protocols

Isolation of human follicles is based on digestion of the tissue by combinations of enzymes. Follicle vitality and morphology are often based on the analysis of pooled follicles of different maturation stages. Information is therefore lacking on the effect of the isolation protocol to individual follicles of different maturation stages. A study was conducted using five protocols combining different enzymes and varying concentrations. Isolated follicles were classified according to their maturation stages, counted and characterized for vitality, morphology, early apoptosis and organization of transzonal projections. No statistical differences were found between the protocols when outcome parameters were analysed on a pool of follicles regardless of their maturation status. Differences were observed in quality when the follicles were analysed separately according to their maturation status. Combining morphologic characteristics and vitality, both Liberase DH and Liberase TM combined with collagenase IV were better at isolating high-quality primordial follicles, compared with collagenase IV. No statistical difference between the isolation protocols was found for primary follicles. If only high-quality isolated secondary follicles are needed, collagenase IV is found to be most advantageous. Follicles of different maturation stages react differently when enzymatic isolation protocols are compared.

Effects of erythropoietin on ischemia, follicular survival, and ovarian function in ovarian grafts

Ovarian tissue transplantation is performed to preserve fertility in patients undergoing chemotherapy and radiotherapy. However, ischemia/reperfusion (IR) injury and free radical production occurring during the revascularization of the transplanted tissue are the major limitations of this procedure. The aim of this study was to investigate the effect of erythropoietin (EPO) as an antioxidant on oxidative stress and ovary survival following transplantation. The Naval Medical Research Institute (NMRI) mice (4–5 weeks old) were divided into three groups (six mice per group): control; autograft+saline, and autograft+EPO (500 IU/kg i.p.). After 28 days, ovary compartments were estimated stereologically. DNA fragmentation and plasma malondialdehyde (MDA), progesterone, and estradiol (E2) concentrations were also evaluated. The results were analyzed using one-way ANOVA and Tukey's test, and the means were significantly different at P<0.05. The mean total volume of ovary, cortex, and medulla and the number of follicles increased significantly in the autograft+EPO group (P<0.01). Apoptosis rate in the autograft+EPO group was lower than that in the autograft+saline group. The concentration of MDA decreased significantly in the autografted EPO-treated group than in the autografted saline-treated group (P<0.01). The concentration of E2 increased significantly in the autograft+EPO group than in the autograft+saline group (P<0.01). EPO reduced IR injury, increasing follicle survival and function in grafted ovaries.

Free Persian abstract

A Persian (Farsi) translation of the abstract is freely available online at http://www.reproduction-online.org/content/147/5/733/suppl/DC1

Does stimulation with human gonadotropins and gonadotropin-releasing hormone agonist enhance and accelerate the developmental capacity of oocytes in human ovarian tissue xenografted into severe combined immunodeficient mice?

OBJECTIVE

To assess the capacity of human frozen-thawed ovarian follicles matured in xenografts to form metaphase II (MII) oocytes after xenotransplantation and exogenous stimulation.

DESIGN

Prospective controlled animal study.

SETTING

University hospital gynecology research unit.

PATIENT(S)

Ovarian fragments were obtained from 17 women with malignant diseases who wished to cryopreserve ovarian tissue for later pregnancy before chemotherapy.

ANIMAL(S)

Eighty-eight female severe combined immunodeficient (SCID) mice.

INTERVENTION(S)

Cryopreserved human ovarian tissue was grafted into oophorectomized SCID mice. The mice were divided into three groups: Group A received hMG alone every 2 days for a maximum of 24 weeks; group B additionally received nRH agonist (GnRHa) every 4 weeks; and group C was an untreated control group.

MAIN OUTCOME MEASURE(S)

Follicular density, morphology, proliferation, oocyte maturation, malignant cell contamination.

RESULT(S)

Follicle survival and development were similar in all three groups. No significant interactions between the stimulation protocols and grafting duration were noted. Three MII oocytes were observed in grafted follicles. Two MII oocytes were harvested without stimulation. None of the mice showed signs of reintroduced malignancy, nor did microscopic evaluation of the grafts raise any suspicion of residual malignant disease.

CONCLUSION(S)

After xenotransplantation, human primordial follicles can be matured to MII oocytes even without stimulation. Administering human gonadotropin and GnRHa does not enhance the developmental capacity of xenografted oocytes. The optimal stimulation schedule for grafted tissue remains unknown.

Effect of Human Endothelial Progenitor Cell (EPC)- or Mouse Vascular Endothelial Growth Factor-Derived Vessel Formation on the Survival of Vitrified/Warmed Mouse Ovarian Grafts

The aim of this study was to evaluate the effectiveness of improving angiogenesis at graft sites on the survival of follicles in transplanted ovarian tissue. Matrigel containing 5 × 10⁵ of cord blood-derived endothelial progenitor cells (EPCs) or 200 ng of mouse vascular endothelial growth factor (VEGF) was injected subcutaneously into BALB/c-Nu mice. After 1 week, vitrified/warmed ovaries from female B6D2F1 mice were subcutaneously transplanted into the injection sites. After 1, 2, and 4 weeks posttransplantation, the ovaries were recovered and subjected to histological analysis. Oocytes were collected from the transplanted ovaries, and their fertilization, embryonic development, and delivery were also observed. Vitrified/warmed ovaries transplanted into EPC- or VEGF-treated sites developed more blood vessels and showed better follicle survival than those transplanted into sham-injected sites. Normal embryonic development and consequent live births were obtained using oocytes recovered from cryopreserved/transplanted ovaries. Treatment with EPCs or VEGF could prevent the ischemic damage during the early revascularization stage of ovarian transplantation.

FTY720 and cyclosporin protect ovarian tissue grafted into rabbits

OBJECTIVE

To determine whether FTY720 combined with CsA has immunomodulatory effects on human ovarian tissue transplanted to the back muscle of rabbits for an 8-week period.

STUDY DESIGN

We selected rabbits as recipients of ovarian xenografts with and without treatment by CsA and FTY720. Ovarian fragments from twelve patients were cut into 2 mm × 2 mm, 1-2mm thick pieces and randomly distributed into four groups: Group 1 (FTY720 2 mg/kg/d+CsA 3 mg/kg/d), Group 2 (FTY720 1 mg/kg/d+CsA 3mg/kg/d), Group 3 (FTY720 0.5 mg/kg/d+CsA 3mg/kg/d) and Group 4 for control (CsA 3 mg/kg/d). FTY720 was started three days before transplantation and was given daily after transplantation. CsA was administrated post-transplantation. All the animals were killed 8 weeks post- transplantation. Levels of serum estrogen (E2), interferon-γ (IFN-γ) and interleukin-4 (IL-4) were detected by radioimmunoassay and ELISA. Anti-CD31 and anti-Ki-67 antibodies were used to evaluate neo-vascularization in xenografts and proliferation activity of ovarian follicles. Peripheral CD4+/CD8+ T cells were analyzed by flow cytometry.

RESULTS

Combined treatment with cyclosporin A and FTY720 improved graft survival and reduced peripheral CD4+ and CD8+ T cell counts compared to treatment with cyclosporin A alone. Neovascularization took place in the peripheral zone of the xenograft while granulosa cells, positively stained by Ki-67, were found in early-stage follicles and stromal cells in the combined treatment groups.

CONCLUSION

FTY720 in combination with cyclosporin A maintains human ovarian xenografts in these rabbit models.

VEGF and bFGF increase survival of xenografted human ovarian tissue in an experimental rabbit model

PURPOSE

The aim of this study is to determine whether vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) could increase the survival of xenografted human ovarian tissue in an experimental rabbit model.

METHODS

Fresh human ovarian tissue was xenotransplanted into the back muscle of 25 castrated female New Zealand rabbits for 6 weeks with the immunosuppression of FTY720 (2 mg/kg/d). Rabbits were randomly divided into five experimental groups: (A) graft and host treatment with VEGF (50 ng/ml); (B) graft and host treatment with bFGF (100 ng/ml); (C) graft and host treatment with VEGF(50 ng/ml) + bFGF (100 ng/ml); (D) graft and host treatment with normal saline; (E) control group, no treatment. 4 weeks after transplantation, human menopausal gonadotropin (HMG) 10 IU was administered every second day in group A, group B, group C and group D for 2 weeks. Graft survival was assessed by graft recovery rate, histological analysis, immunohistochemical staining for CD31 and Ki-67expression, TUNEL assay.

RESULTS

After 6 weeks of grafting, the number of CD31-positive stained cells increased significantly in group A, group B and group C compared to the control group. All groups showed strong Ki-67 immunostaining in ovarian stroma. Only one rabbit in group C retained the grafts' follicles. Grafting resulted in relative lower fibrosis in group A and group C compared to the control group. Apoptosis was significantly lower in group C compared to the control group.

CONCLUSIONS

Fresh human ovarian cortex grafted into the back muscle of rabbit can sustain part of ovarian tissue function with the immunosuppression of FTY720, although follicle number diminishes significantly after grafting. The administration of VEGF and bFGF, especially the combination of them, may trigger angiogenesis, reduce apoptosis and fibrosis, increase survival in transplanted human ovarian tissue.

The root of reduced fertility in aged women and possible therapentic options: current status and future perspects

It is well known that maternal ageing not only causes increased spontaneous abortion and reduced fertility, but it is also a high genetic disease risk. Although assisted reproductive technologies (ARTs) have been widely used to treat infertility, the overall success is still low. The main reasons for age-related changes include reduced follicle number, compromised oocyte quality especially aneuploidy, altered reproductive endocrinology, and increased reproductive tract defect. Various approaches for improving or treating infertility in aged women including controlled ovarian hyperstimulation with intrauterine insemination (IUI), IVF/ICSI-ET, ovarian reserve testing, preimplantation genetic diagnosis and screening (PGD/PGS), oocyte selection and donation, oocyte and ovary tissue cryopreservation before ageing, miscarriage prevention, and caloric restriction are summarized in this review. Future potential reproductive techniques for infertile older women including oocyte and zygote micromanipulations, derivation of oocytes from germ stem cells, ES cells, and iPS cells, as well as through bone marrow transplantation are discussed.

Does early cell death cause germ cell loss after intratesticular tissue grafting?

OBJECTIVE

To assess cell death in intratesticular grafts.

DESIGN

Experimental animal study.

SETTING

University.

ANIMAL(S)

F1-hybrids from SV129 X C57BL.

INTERVENTION(S)

Intratesticular tissue transplantation was performed and cell death in the grafts was evaluated at different time points after transplantation.

MAIN OUTCOME MEASURE(S)

Apoptotic cell death in spermatogonia was evaluated by flow cytometry with the use of the annexin V assay. Immunohistochemistry was used to evaluate graft development and the global occurrence of cell death.

RESULT(S)

The highest level of spermatogonia-specific cell death was found on days 4 and 10, although no statistical difference was observed compared with control tissue. Statistically significant reductions in tubule integrity were observed 1 day and 2 months after transplantation. More degenerated tubules were observed in the center of the grafts 1 and 4 days after transplantation, and higher numbers of apoptotic tubules were found 1 day after transplantation. No difference in overall cell death was observed between grafts and controls for any time point except for the frozen grafts 1 day after transplantation.

CONCLUSION(S)

Spermatogonia-specific apoptosis does not explain the stem cell loss observed after intratesticular tissue grafting; it probably results from degeneration of tubules in the center of the graft owing to hypoxia during the first days after transplantation.

Clinical review: Present and future prospects of male fertility preservation for children and adolescents

CONTEXT

Rapid progress in fertility preservation strategies has led to the investigation of ways in which fertile gametes could be generated from cryopreserved immature testicular tissue. Childhood cancer patients remain the major group that can benefit from these techniques. Other potential candidates include patients undergoing gonadectomy and patients with Klinefelter's syndrome and cryptorchid testes. This review aims to present an overview of the current state of knowledge in experimental germ cell transplantation, testicular tissue transplantation, and germ cell culture as fertility preservation methods for males.

METHODOLOGY

We included English articles published in PubMed as well as personal files with the focus on studies including human or nonhuman material.

MAIN FINDINGS

Germ cell and testicular tissue transplantation demonstrate clinical options to mature germ cells from immature primate testicular tissue. The most promising approach involves autologous grafting of immature testicular tissue, whereas germ cell maturation in vitro provides the best strategies to overcome problems of cancer contamination in cryopreserved testicular tissue. Three-dimensional and organ culture systems offer the possibility to differentiate immature male germ cells up to the stage of elongated spermatids. Further characterization of early germ cell development in humans is needed to modify these systems for clinical use.

FSH prevents depletion of the resting follicle pool by promoting follicular number and morphology in fresh and cryopreserved primate ovarian tissues following xenografting

BACKGROUND

Cryopreservation and transplantation of ovarian tissue is one option for re-establishing ovarian function, but optimal conditions for graft sustainment and follicular survival are still considered experimental. The present study aims to analyze the effect of FSH treatment on the resting follicle pool in fresh and cryopreserved primate ovarian tissues following xenografting.

METHODS

Ovarian tissues from adult marmosets were grafted freshly or following cryopreservation to ovarectomized nude mice treated with FSH 25 IU twice daily post transplantation or left untreated as controls. Grafts were retrieved 2 or 4 weeks after transplantation to evaluate the number and morphological appearance of follicles.

RESULTS

Early start of FSH treatment within 1 week following transplantation partly prevents primordial follicle loss in fresh and frozen-thawed tissues, whereas after a 3 weeks time interval this effect is present only in fresh tissues. A similar positive effect of early, but not later FSH treatment on primary follicles is seen in fresh tissues compared to only marginal effects in frozen-thawed tissues. The percentage of morphologically normal follicles is generally increased in FSH treated tissues, whereas the percentage of primary follicles over all primordial and primary follicles is increased by FSH only in freshly-grafted tissues.

CONCLUSIONS

FSH treatment alleviates depletion of the resting follicle pool and promotes normal follicular morphology both in freshly and frozen-thawed grafted tissues. In previously cryopreserved tissues, applying to most of the tissues intended for clinical use in fertility preservation attempts, its positive effect on primordial follicle numbers and potential graft sustainment is dependent on an early start of treatment within one week of transplantation.

Autologous ectopic grafting of cryopreserved testicular tissue preserves the fertility of prepubescent monkeys that receive sterilizing cytotoxic therapy

Boys faced with future sterility as a result of the need of a sterilizing cancer therapy might avoid this fate by engraftment of cryopreserved immature testicular tissue after therapy is completed. Efforts to address this important survivorship issue have been encouraged by reports of the long-term survival and proliferation of human spermatogonia after xenotransplant of cryopreserved immature testicular tissue into immunocompromised murine hosts. However, spermatogenic arrest at the pachytene spermatocyte stage that occurs in this situation has been associated with a failure in sperm production. In this study, we used a prepubescent simian model to address the possibility that testicular tissue engraftment is insufficiently supported in the model to allow suitable maturation of germ cells. Briefly, we carried out autologous orthotopic grafting of cryopreserved testicular tissue from four prepubescent monkeys and one pubescent rhesus monkey after testicular irradiation and castration of the host animal. Five months after implantation of scrotal grafts, we determined that 3% to 7% of the autografts could be recovered with spermatogenesis proceeding through spermatozoa formation in 13% to 17% of the seminiferous tubules formed in the grafts. In contrast, Sertoli cell-only tubules were detected in parallel xenografts transplanted into immunocompromised mice. Our results show that cryopreservation of testicular tissue from prepubescent primates can maintain the fully functional capacity of spermatogonia to produce sperm, but that host conditions are critical for spermatogenic maturation. Furthermore, our results establish an initial perspective on the quantity of cryopreserved material needed to ensure success in preserving fertility through testicular tissue grafts.

Follicle development in cryopreserved bitch ovarian tissue grafted to immunodeficient mouse

The present study evaluated: (1) in vivo follicular development in canine ovarian tissue after slow freezing and xenotransplantation; and (2) the use of erythropoietin (EPO) as an angiogenic factor to optimise the transplantation procedure. Frozen-thawed ovarian tissue from five bitches was grafted into severe combined immunodeficient (SCID) mice (n=47) treated with or without EPO (500 IU kg(-1), once daily for 3 days) (Groups A and B, respectively) and analysed after 0, 1, 8 or 16 weeks. Follicle grade, follicle density, follicle morphology and stromal cells density were assessed by histological analysis, whereas vascularisation of the graft was quantified by immunohistochemistry with anti-α-smooth muscle actin antibody. Despite a massive loss of follicles after grafting, secondary follicle density was higher at 8 and 16 weeks than at 1 week regardless of EPO treatment. EPO significantly improved early follicle morphology and stromal cell density after 8 weeks and blood vessel density at 16 weeks after transplantation (P<0.05). Intact secondary follicles with more than three granulosa cells layers were observed 16 weeks after transplantation. The results suggest that canine ovarian tissue can be successfully preserved by our slow-freezing protocol because the tissue showed follicular growth after xenotransplantation. EPO treatment did not lessen the massive loss of follicles after transplantation.

Fertility-sparing surgery in early epithelial ovarian cancer: a viable option?

Epithelial ovarian cancer (EOC) continues to represent one of the most lethal conditions in women in the western countries. With the shifting of childbearing towards higher age, EOC increasingly affects women with active childbearing wish, resulting in major impacts on treatment management. Next to the optimal therapeutic treatment strategies, gynecologic oncologists are being asked to incorporate into their decision-making processes the patients' wish for fertility preserving alternatives ideally without compromising oncologic safety. Nowadays, fertility-sparing surgery represents an effective alternative to conventional radical cytoreduction in younger women with early stages of the disease. As such, this paper considers indications for fertility sparing surgery in EOC, reflects on outcomes from the oncologic and reproductive data of the largest and most relevant series outcomes data, reporting on fertility sparing techniques in EOC, reviews medicamentous efforts to prevent chemotherapy induced gonadotoxicity, and discusses future aspects in the gynecologic cancer management.

Possible improvements in human ovarian grafting by various host and graft treatments

BACKGROUND

Anticancer treatment poses a high risk of ovarian failure. In many cases cryopreservation of ovarian tissue is the only option for fertility preservation. Although autologous transplantation of cryopreserved-thawed ovarian tissue has resulted in live births, slow graft revascularization and ischemia after transplantation leads to substantial follicular loss. Therefore, methods to improve and hasten graft vascularization are needed. The aim of the study was to examine the benefits of host and graft treatments with melatonin, hyaluronan (HA), vascular endothelial growth factor A (VEGF-A) and vitamin E with regard to the outcome of human ovarian tissue grafting.

METHODS

Five young cancer patients who underwent laparoscopic ovarian surgery for fertility preservation donated ovarian tissue. Thawed ovarian samples were transplanted into immunodeficient mice divided into seven groups: (A) no treatment; (B) host treatment with melatonin before and after grafting; (C) graft incubation with HA-rich biological glue before transplantation; (D) host as in (B), graft as in (C); (E) host as in (B), graft incubation with VEGF-A and vitamin E; (F) graft as in (C) combined with VEGF-A and vitamin E; (G) host as in (B), graft as in (F). Graft survival was assessed by follicle counts, apoptosis assay and immunohistochemical staining for proliferating cell nuclear antigen and VEGF-A expression.

RESULTS

Only grafts implanted in melatonin-treated hosts and grafts incubated with HA-rich biological glue retained their original size. Apoptosis was significantly lower after host treatment with melatonin and graft incubation with HA-rich biological glue plus VEGF-A and vitamin E than in untreated grafts; apoptosis was specifically low in Group G. There were significantly more atretic follicles in the untreated group than in most treated groups.

CONCLUSIONS

The findings suggest that host treatment with melatonin or graft incubation with HA-rich biological glue, especially when combined with VEGF-A and vitamin E improves graft survival. This protocol can be applied and holds promise in ovarian autotransplantation for fertility restoration.

Impact of freezing and thawing of human ovarian tissue on follicular growth after long-term xenotransplantation

PURPOSE

To assess follicular growth after xenografting in order to understand how freezing and/or grafting may affect follicular development.

METHODS

Human ovarian biopsies were used for fresh and frozen-thawed xenografting to SCID mice. After xenotransplantation, follicular morphology and proportion, oocyte and follicle diameter, and quantitative and qualitative parameters of antral follicles were analyzed.

RESULTS

The proportion of growing follicles was significantly higher in grafted than non-grafted ovarian tissue. Follicular growth to the antral stage was observed and there was no significant difference in oocyte or follicle diameter in fresh or frozen-thawed grafts. Although no significant difference was observed in antral area or zona pellucida thickness, the theca layer in antral follicles from frozen-thawed grafted tissue was found to be significantly thinner than in fresh grafts.

CONCLUSION

Antral follicles obtained after grafting of frozen-thawed human ovarian tissue showed a thinner theca cell layer compared to those from fresh grafts, which could affect follicular development and function. Further studies are nevertheless warranted to confirm the identity of theca cells and assess if they retain the ability to respond to luteinizing hormone and produce androgens.

Improving posttransplantation survival of human ovarian tissue by treating the host and graft

OBJECTIVE

To improve posttransplantation survival of frozen-thawed human ovarian tissue in immunodeficient mice.

DESIGN

Histologic study of transplanted human ovaries after treating the host and graft.

SETTING

Infertility unit, university-affiliated tertiary medical center.

PATIENT(S)

Ovarian tissue from six girls/women (aged 5-23 years) who had undergone ovarian laparoscopy for fertility preservation.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Thawed ovarian samples were transplanted into the back muscle of immunodeficient mice divided into four groups: A) no treatment; B) host treatment with vitamin E and gonadotropins before and after grafting; C) graft incubation with vascular endothelial growth factor A (VEGF-A) and vitamin E before transplantation; and D) host as in B, graft as in C. Ungrafted thawed samples served as control. Assessment of graft survival was conducted by follicle counts, apoptosis evaluation, immunohistochemical stainings for proliferating cell nuclear antigen (PCNA) and VEGF-A expression.

RESULT(S)

Only grafts incubated before transplantation (groups C and D) retained their original size. Follicle number was low in all grafts. PCNA expression was found in most grafts. Apoptosis was significantly lower in the untreated and treated grafts transplanted into treated hosts (groups B and D) than in ungrafted-thawed samples and group A grafts. All grafted groups had significantly higher expression of VEGF-A than ungrafted-thawed samples.

CONCLUSION(S)

Survival of transplanted human ovarian tissue may be improved by treatment of the host and graft. Further studies to evaluate treatments with a potential benefit in human ovarian autotransplantation are needed.

Enhancement of neoangiogenesis and follicle survival by sphingosine-1-phosphate in human ovarian tissue xenotransplants

Ovarian transplantation is one of the key approaches to restoring fertility in women who became menopausal as a result of cancer treatments. A major limitation of human ovarian transplants is massive follicular loss during revascularization. Here we investigated whether sphingosine-1-phosphate or its receptor agonists could enhance neoangiogenesis and follicle survival in ovarian transplants in a xenograft model. Human ovarian tissue xenografts in severe-combined-immunodeficient mice were treated with sphingosine-1-phosphate, its analogs, or vehicle for 1–10 days. We found that sphingosine-1-phosphate treatment increased vascular density in ovarian transplants significantly whereas FTY720 and SEW2871 had the opposite effect. In addition, sphingosine-1-phosphate accelerated the angiogenic process compared to vehicle-treated controls. Furthermore, sphingosine-1-phosphate treatment was associated with a significant proliferation of ovarian stromal cell as well as reduced necrosis and tissue hypoxia compared to the vehicle-treated controls. This resulted in a significantly lower percentage of apoptotic follicles in sphingosine-1-phosphate-treated transplants. We conclude that while sphingosine-1-phosphate promotes neoangiogenesis in ovarian transplants and reduces ischemic reperfusion injury, sphingosine-1-phosphate receptor agonists appear to functionally antagonize this process. Sphingosine-1-phosphate holds great promise to clinically enhance the survival and longevity of human autologous ovarian transplants.