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

De novo design of a nanoregulator for the dynamic restoration of ovarian tissue in cryopreservation and transplantation

The cryopreservation and transplantation of ovarian tissue underscore its paramount importance in safeguarding reproductive capacity and ameliorating reproductive disorders. However, challenges persist in ovarian tissue cryopreservation and transplantation (OTC-T), including the risk of tissue damage and dysfunction. Consequently, there has been a compelling exploration into the realm of nanoregulators to refine and enhance these procedures. This review embarks on a meticulous examination of the intricate anatomical structure of the ovary and its microenvironment, thereby establishing a robust groundwork for the development of nanomodulators. It systematically categorizes nanoregulators and delves deeply into their functions and mechanisms, meticulously tailored for optimizing ovarian tissue cryopreservation and transplantation. Furthermore, the review imparts valuable insights into the practical applications and obstacles encountered in clinical settings associated with OTC-T. Moreover, the review advocates for the utilization of microbially derived nanomodulators as a potent therapeutic intervention in ovarian tissue cryopreservation. The progression of these approaches holds the promise of seamlessly integrating nanoregulators into OTC-T practices, thereby heralding a new era of expansive applications and auspicious prospects in this pivotal domain.

Research progress on mechanism of follicle injury after frozen ovarian tissue transplantation and protective strategies

The iatrogenic ovarian dysfunction caused by cancer treatment have been increasing, along with the age at onset of malignant tumors getting younger, the survival of cancer patients being longer, as well as the delayed childbearing age for females; therefore it becomes a major clinical challenge to preserve the fertility of these patients. Ovarian tissue cryopreservation is the only solution for female cancer patients in prepubertal ages and those who cannot delay gonadotoxic therapy. However, the successful rate of cryopreservation and transplantation of ovarian tissue is still low at present due to the risk of ischemia and hypoxia of grafted tissues. Abnormal activation of primordial follicle and ischemia-reperfusion injury after blood supply recovery also cause massive loss of follicles in grafted ovarian tissues. It has been tried in various studies to reduce the damage of follicles during freezing and transplantation by adding certain drugs, and extend the duration of endocrine and reproductive function in patients with ovarian transplantation. For example, melatonin, N-acetylcysteine, erythropoietin or other antioxidants are used to reduce oxidative stress; mesenchymal stem cells derived from different tissues, basic fibroblast growth factor, vascular endothelial growth factor, angiopoietin 2 and gonadotropin are used to promote revascularization; anti-Müllerian hormone and rapamycin are used to reduce abnormal activation of primordial follicles. This article reviews the research progress on the main mechanisms of follicle loss after ovarian tissue transplantation, including hypoxia, ischemia-reperfusion injury and associated cell death, and abnormal activation of follicles; and explores the methods of reducing graft follicle loss to provide reference for improving the efficiency of ovarian tissue cryopreservation and transplantation.

Comparison of angiogenic potential in vitrified vs. slow frozen human ovarian tissue

Vitrification of ovarian tissue is a promising alternative approach to the traditional slow freezing method. Few empirical investigations have been conducted to determine the angiogenic profiles of these two freezing methods. In this study we aimed to answer the question whether one of the cryopreservation methods should be preferred based on the secretion of angiogenic factors. Tissue culture with reduced oxygen (5%) was conducted for 48 h with samples of fresh, slow frozen/thawed and vitrified/rapid warmed ovarian cortex tissue from 20 patients. From each patient, tissue was used in all three treatment groups. Tissue culture supernatants were determined regarding cytokine expression profiles of angiogenin, angiopoietin-2, epidermal growth factor, basic fibroblast growth factor, heparin binding epidermal growth factor, hepatocyte growth factor, Leptin, Platelet-derived growth factor B, placental growth factor and vascular endothelial growth factor A via fluoroimmunoassay. Apoptotic changes were assessed by TUNEL staining of cryosections and supplemented by hematoxylin and eosin and proliferating cell nuclear antigen staining. Comparing the angiogenic expression profiles of vitrified/rapid warmed tissue with slow frozen/thawed tissue samples, no significant differences were observed. Detection of apoptotic DNA fragmentation via TUNEL indicated minor apoptotic profiles that were not significantly different comparing both cryopreservation methods. Vitrification of ovarian cortical tissue does not appear to impact negatively on the expression profile of angiogenic factors and may be regarded as an effective alternative approach to the traditional slow freezing method.

Ovarian rescue in women with premature ovarian insufficiency: facts and fiction

The ovary has a comparatively short functional lifespan compared with other organs, and genetic and pathological injuries can further shorten its functional life. Thus, preserving ovarian function should be considered in the context of women with threats to ovarian reserve, such as ageing, premature ovarian insufficiency (POI) and diminished ovarian reserve (DOR). Indeed, one-third of women with POI retain resting follicles that can be reactivated to produce competent oocytes, as proved by the in-vitro activation of dormant follicles. This paper discusses mechanisms and clinical data relating to new therapeutic strategies using ovarian fragmentation, stem cells or platelet-rich plasma to regain ovarian function in women of older age (>38 years) or with POI or DOR. Follicle reactivation techniques show promising experimental outcomes and have been successful in some cases, when POI is established or DOR diagnosed; however, there is scarce clinical evidence to warrant their widespread clinical use. Beyond these contexts, also discussed is how new insights into the biological mechanisms governing follicular dynamics and oocyte competence may play a role in reversing ovarian damage, as no technique modifies oocyte quality. Additional studies should focus on increasing follicle number and quality. Finally, there is a small but important subgroup of women lacking residual follicles and requiring oocyte generation from stem cells.

Metabolic and secretory recovery of slow frozen-thawed human ovarian tissue in vitro

Within the options available for fertility preservation, cryopreservation of ovarian cortical tissue has become an important technique. Freezing and thawing procedures have been optimized to preserve tissue integrity and viability. However, the improvement of the tissue retransplantation is currently of great interest. Rapid angiogenesis is needed at the retransplantation site to accomplish sufficient blood supply to provide oxygen and nutrients. Many studies address this issue. However, we need to understand the physiology of the thawed tissue to gain further understanding of the complexities of the procedure. As freezing and thawing generally impairs cellular metabolism, we aimed to characterize the changes in metabolic activity and secretion of the angiogenic factor vascular endothelial growth factor-A (VEGF-A) of frozen-thawed ovarian cortical tissue over time. Biopsy punches of ovarian cortical tissue from patients undergoing fertility preservation were maintained in culture without freezing or after a slow-freezing and thawing procedure. VEGF-A secretion was measured after 48 h by ELISA. To examine temporary changes, metabolic activity was assessed for both fresh and frozen-thawed tissue of the same patient. Metabolic activity and VEGF-A secretion were measured at 0, 24 and 48 h in culture. Thawed ovarian cortical tissue secreted significantly less VEGF-A compared to fresh ovarian cortical tissue within 48 h of culture. After thawing, metabolic activity was significantly reduced compared to fresh ovarian cortex but over the course of 48 h, the metabolic activity recovered. Similarly, VEGF-A secretion of thawed tissue increased significantly over 48 h. Here, we have shown that it takes 48 h for ovarian cortical tissue to recover metabolically after thawing, including VEGF-A secretion.

Bone marrow mesenchymal stem cells in premature ovarian failure: Mechanisms and prospects

Premature ovarian failure (POF) is a common female reproductive disorder and characterized by menopause, increased gonadotropin levels and estrogen deficiency before the age of 40 years old. The etiologies and pathogenesis of POF are not fully clear. At present, hormone replacement therapy (HRT) is the main treatment options for POF. It helps to ameliorate perimenopausal symptoms and related health risks, but can't restore ovarian function and fertility fundamentally. With the development of regenerative medicine, bone marrow mesenchymal stem cells (BMSCs) have shown great potential for the recovery of ovarian function and fertility based on the advantages of abundant sources, high capacity for self-renewal and differentiation, low immunogenicity and less ethical considerations. This systematic review aims to summarize the possible therapeutic mechanisms of BMSCs for POF. A detailed search strategy of preclinical studies and clinical trials on BMSCs and POF was performed on PubMed, MEDLINE, Web of Science and Embase database. A total of 21 studies were included in this review. Although the standardization of BMSCs need more explorations, there is no doubt that BMSCs transplantation may represent a prospective therapy for POF. It is hope to provide a theoretical basis for further research and treatment for POF.

Effects of hypoxia-preconditioned HucMSCs on neovascularization and follicle survival in frozen/thawed human ovarian cortex transplanted to immunodeficient mice

Background

The massive loss of follicles in the early stage of ovarian tissue transplantation is considered a significant restriction to the efficacy of ovarian tissue cryopreservation (OTC) and transplantation (OT). The use of mesenchymal stem cells (MSCs) before transplantation of ovarian fragments shortened the hypoxic period and boosted neovascularization. Hypoxia-preconditioned MSCs can enhance the potential of angiogenesis. Can hypoxia-preconditioned human umbilical cord mesenchymal stem cell (HucMSCs) and ovarian tissue co-xenotransplantation improve more neovascularization and subsequently more follicle survival in human ovarian tissue?

Methods

Frozen-thawed cortical pieces from 4 patients were transplanted into the bilateral renal capsule of immune-deficient nude mice without HucMSCs or normoxia/hypoxia-preconditioned HucMSCs. Sixty-four mice were randomly distributed into 4 groups. In each group, the mice were euthanized for blood and/or graft retrieval on post-transplantation days 3 (n = 8) and 7 (n = 8), respectively. Non-grafted frozen-thawed ovarian fragment was taken for non-grafted control. Grafts were histologically processed and analysed for follicle density and atretic follicles by HE, neovascularization by CD34 and CD31 immunohistochemical staining, primordial follicle growth by Ki67 staining, and apoptosis of stromal cell and follicles by immunofluorescence using TUNEL. The ROS and TAC levels of grafted and non-grafted tissue were assessed. We evaluated the protein expression of HIF1α, VEGFA, pAkt, Akt, and GDF9 in grafted and non-grafted ovarian tissue. E2, Prog, AMH, and FSH levels in the plasma of mice were measured after 3 and 7 days of OT.

Results

Hypoxia-preconditioned HucMSCs positively protect the grafted ovarian tissue by significantly decreasing the apoptosis and increasing higher expression of CD31, CD34, and VEGFA for earlier angiogenesis. They are crucial to preserving the resting primordial follicle pool by modulation of follicle death.

Conclusion

This is the first study to demonstrate that co-transplantation of hypoxia-preconditioned HucMSC with ovarian tissue improved earlier vascularization of ovarian grafts in the early post-grafting period, which correlates with increased follicle survival and reduced apoptosis. The HIF1α/VEGFA signal pathways may play an important role in elucidating the mechanisms of action of hypoxia-preconditioned HucMSCs with regard to OT and clinical implementation.

Medical Grade Honey as a Promising Treatment to Improve Ovarian Tissue Transplantation

Ovarian tissue cryopreservation is a female fertility preservation technique that presents major challenges for the maintenance of follicular viability after transplantation. The aim of this study was to evaluate and compare the application of L-Mesitran Soft^®, a product containing 40% medical grade honey (MGH), with other strategies to improve ovarian grafts’ viability. For this purpose, bovine ovarian tissue was vitrified, warmed and randomly assigned to culture groups: (1) control, (2) MGH 0.2% in vitro, (3) MGH in vivo (direct application in the xenotransplantation), (4) vascular endothelial growth factor (VEGF 50 ng/mL) and (5) vitamin D (100 Nm), during a 48 h period. A sixth group (6) of fragments was thawed on transplantation day and was not cultured. The tissue was xenotransplanted into immunodeficient (Rowett nude homozygous) ovariectomized rats. Grafts were analyzed 48 h after culture, and 7 and 28 days after transplantation. The tissue was subjected to histological and immunohistochemical analysis. Treatments using MGH showed the highest angiogenic and cell proliferation stimulation, with cellular apoptosis, within a healthy cellular turnover pathway. In conclusion, MGH should be considered as a potentially effective and less expensive strategy to improve ovarian tissue transplantation.

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

CONTEXT

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

AIMS

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

METHODS

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

CONCLUSIONS

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

IMPLICATIONS

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

VEGFA165 can rescue excess steroid secretion, inflammatory markers, and follicle arrest in the ovarian cortex of High A4 cows†

A population of cows with excess androstenedione (A4; High A4) in follicular fluid, with follicular arrest, granulosa cell dysfunction, and a 17% reduction in calving rate was previously identified. We hypothesized that excess A4 in the ovarian microenvironment caused the follicular arrest in High A4 cows and that vascular endothelial growth factor A would rescue the High A4 phenotype. In trial 1, prior to culture, High A4 ovarian cortex (n = 9) had greater numbers of early stage follicles (primordial) and fewer later-stage follicles compared to controls (n = 11). Culture for 7 days did not relieve this follicular arrest; instead, High A4 ovarian cortex had increased indicators of inflammation, anti-Mullerian hormone, and A4 secretion compared to controls. In trial 2, we tested if vascular endothelial growth factor A isoforms could rescue the High A4 phenotype. High A4 (n = 5) and control (n = 5) ovarian cortex was cultured with (1) PBS, (2) VEGFA165 (50 ng/mL), (3) VEGFA165B (50 ng/mL), or (4) VEGFA165 + VEGFA165B (50 ng/mL each) for 7 days. Follicular progression increased with VEGFA165 in High A4 cows with greater early primary, primary, and secondary follicles than controls. Similar to trial 1, High A4 ovarian cortex secreted greater concentrations of A4 and other steroids and had greater indicators of inflammation compared to controls. However, VEGFA165 rescued steroidogenesis, oxidative stress, and fibrosis. The VEGFA165 and VEGFA165b both reduced IL-13, INFα, and INFβ secretion in High A4 cows to control levels. Thus, VEGFA165 may be a potential therapeutic to restore the ovarian steroidogenic microenvironment and may promote folliculogenesis.

Ovarian tissue features assessed in bovine fetuses after vitrification and xenotransplantation procedures

Cryopreservation and transplantation of ovarian tissue are proposed methods for the restoration of endocrine function and reproductive potential. Therefore, this study aimed to evaluate the effects of vitrification and xenotransplantation on follicle viability, activation, stromal cell integrity, vascularization, and micronuclei formation. Bovine fetal ovaries were fragmented and assigned to the following groups: Fresh control (FC), ovarian fragments immediately fixed; Vitrified control (VC), ovarian fragments vitrified; Vitrified xenotransplanted (VX), ovarian fragments vitrified and xenotransplanted; and Fresh xenotransplanted (FX), ovarian fragments xenotransplanted. Ovarian fragments were grafted in female BALB/c mice and recovered after 14 days. Follicular viability was preserved (P >  0.05) in VC group. The rate of developing follicles was greater (P <  0.05) in the FX group compared to other groups. Follicular density was higher (P <  0.05) in the VC group than the FC, VX, and FX groups. A decrease (P <  0.05) of stromal cell density was recorded after vitrification (VC vs. FX). Blood vessel density decreased in VC, VX, and FX groups compared with the FC group, and blood vessel density was correlated with follicular viability (positively; P =  0.07) and developing follicles (negatively; P <  0.001). Both vitrification and xenotransplantation groups (VC, VX, and FX) had a greater (P <  0.05) number of cells with one MN compared to the FC group. In summary, our findings showed that both vitrification and xenotransplantation modified blood vessel, follicular and stromal cell densities, follicular viability and activation, and micronuclei formation in ovarian tissue.

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.

Therapeutic Angiogenesis for Ovarian Transplantation through Ultrasound-Targeted Microbubble Destruction

Timely angiogenesis and effective microcirculation perfusion are essential for the survival and functional recovery of transplanted ovaries. Ultrasound-targeted microbubble destruction (UTMD) can lead to angiogenesis and increase flow perfusion by causing transient inflammation. The purpose of this study was to evaluate the effects of UTMD on transplanted ovarian revascularization and survival. In vitro, for the criteria of cell viability and tube formation capability, the optimal exposure parameters were determined to be a microbubble concentration of 1 × 10⁸/mL, mechanical index of 1 and exposure time of 30 s. After ovarian transplantation, 40 female Sprague Dawley rats were divided into four groups: transplantation alone, ultrasound alone, microbubbles alone and ultrasound and microbubbles (UTMD). At 7 d after transplantation, ovarian perfusion was assessed using qualitative and quantitative methods. The effect of angiogenesis was assessed by contrast-enhanced ultrasound, laser Doppler perfusion imaging and histologic analysis. The results, in which ovarian perfusion was highest in the UTMD group, suggest that UTMD can effectively improve ovarian perfusion. Compared with the other three groups, the number of follicles, microvascular density and rate of Ki-67-positive cells increased significantly in the UTMD group, while apoptosis decreased significantly (p < 0.05). The study indicates that UTMD promoted ovarian re-vascularization after ovarian transplantation and maintained follicular reserve.

Ovarian tissue damage after grafting: systematic review of strategies to improve follicle outcomes

Frozen-thawed human ovarian tissue endures large-scale follicle loss in the early post-grafting period, characterized by hypoxia lasting around 7 days. Tissue revascularization occurs progressively through new vessel invasion from the host and neoangiogenesis from the graft. Such reoxygenation kinetics lead to further potential damage caused by oxidative stress. The aim of the present manuscript is to provide a systematic review of proangiogenic growth factors, hormones and various antioxidants administered in the event of ovarian tissue transplantation to protect the follicle pool from depletion by boosting revascularization or decreasing oxidative stress. Although almost all investigated studies revealed an advantage in terms of revascularization and reduction in oxidative stress, far fewer demonstrated a positive impact on follicle survival. As the cascade of events driven by ischaemia after transplantation is a complex process involving numerous players, it appears that acting on specific molecular mechanisms, such as concentrations of proangiogenic growth factors, is not enough to significantly mitigate tissue damage. Strategies exploiting the activated tissue response to ischaemia for tissue healing and remodelling purposes, such as the use of antiapoptotic drugs and adult stem cells, are also discussed in the present review, since they yielded promising results in terms of follicle pool protection.

Current and Future Perspectives for Improving Ovarian Tissue Cryopreservation and Transplantation Outcomes for Cancer Patients

Although advances in cancer treatment and early diagnosis have significantly improved cancer survival rates, cancer therapies can cause serious side effects, including ovarian failure and infertility, in women of reproductive age. Infertility following cancer treatment can have significant adverse effects on the quality of life. However, established methods for fertility preservation, including embryo or oocyte cryopreservation, are not always suitable for female cancer patients because of complicated individual conditions and treatment methods. Ovarian tissue cryopreservation and transplantation is a promising option for fertility preservation in pre-pubertal girls and adult patients with cancer who require immediate treatment, or who are not eligible to undergo ovarian stimulation. This review introduces various methods and strategies to improve ovarian tissue cryopreservation and transplantation outcomes, to help patients and clinicians choose the best option when considering the potential complexity of a patient's situation. Effective multidisciplinary oncofertility strategies, involving the inclusion of a highly skilled and experienced oncofertility team that considers cryopreservation methods, thawing processes and devices, surgical procedures for transplantation, and advances in technologies, are necessary to provide high-quality care to a cancer patient.

Alpha Lipoic Acid Supplementation Improves Ovarian Tissue Vitrification Outcome: An Alternative to Preserve the Ovarian Function of Morada Nova Ewe

This study evaluated the effect of adding alpha lipoic acid (ALA) to the vitrification solution of sheep ovarian tissue on 7 days of in vitro culture or 15 days of xenotransplantion. ALA was used at two different concentrations (100 μM: ALA100 and 150 μM: ALA150). Ovarian tissue was evaluated by classical histology (follicular morphology, development, and stromal cell density); immunohistochemistry for forkhead box O3a (FOXO3a); Ki67 (cell proliferation); cluster of differentiation 31 (CD31); and alpha smooth muscle actin (α-SMA). Reactive oxygen species (ROS) levels in ovarian tissue, as well as malondialdehyde (MDA) and nitrite levels in the culture medium, were assessed. Similar percentage of morphologically normal follicles was found in the vitrified ovarian tissue in the presence of ALA100 or ALA150 after in vitro culture or xenotransplantation. Follicular development from all treatments was higher (P < 0.05) than the control group. Moreover, an activation of primordial follicles was observed by FOXO3a. Stromal cell density and immunostaining for Ki67 and CD31 were significantly higher (P < 0.05) in ALA150 vitrified tissue. No difference (P > 0.05) was found in α-SMA between ALA concentrations after in vitro culture or xenograft. ROS levels in the ovarian tissue were similar (P > 0.05) in all treatments, as well as MDA and nitrite levels after 7 days of culture. We concluded that the addition of ALA 150 is able to better preserve the stromal cell density favoring granulosa cell proliferation and neovascularization.

Heterotopic autotransplantation of ovarian tissue in a large animal model: Effects of cooling and VEGF

Heterotopic and orthotopic ovarian tissue autotransplantation techniques, currently used in humans, will become promising alternative methods for fertility preservation in domestic and wild animals. Thus, this study describes for the first time the efficiency of a heterotopic ovarian tissue autotransplantation technique in a large livestock species (i.e., horses) after ovarian fragments were exposed or not to a cooling process (4°C/24 h) and/or VEGF before grafting. Ovarian fragments were collected in vivo via an ultrasound-guided biopsy pick-up method and surgically autografted in a subcutaneous site in both sides of the neck in each mare. The blood flow perfusion at the transplantation site was monitored at days 2, 4, 6, and 7 post-grafting using color-Doppler ultrasonography. Ovarian grafts were recovered 7 days post-transplantation and subjected to histological analyses. The exposure of the ovarian fragments to VEGF before grafting was not beneficial to the quality of the tissue; however, the cooling process of the fragments reduced the acute hyperemia post-grafting. Cooled grafts compared with non-cooled grafts contained similar values for normal and developing preantral follicles, vessel density, and stromal cell apoptosis; lower collagen type III fibers and follicular density; and higher stromal cell density, AgNOR, and collagen type I fibers. In conclusion, VEGF exposure before autotransplantation did not improve the quality of grafted tissues. However, cooling ovarian tissue for at least 24 h before grafting can be beneficial because satisfactory rates of follicle survival and development, stromal cell survival and proliferation, as well as vessel density, were obtained.

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.

Histomorphological, VEGF and TGF-β immunoexpression changes in the diabetic rats' ovary and the potential amelioration following treatment with metformin and insulin

Diabetes mellitus (DM) affects the ovary by reducing the number and diameters of ovarian follicles and increasing atretic follicles. Follicular growth and diameters depend on VEGF production. Hyperglycemia causes ovarian stromal and follicular degeneration then fibrosis by activating TGF-β. Insulin and metformin promote development of ovarian follicles and reduce atretic follicles. Therefore, the present study investigates the ovarian VEGF and TGF-β immune-expression and its variations in diabetic, insulin and metformin-treated rats. Forty adult female albino rats were divided equally into four groups: control, diabetic (STZ-induced diabetes), diabetic metformin-treated group (100 mg/kg/day orally/eight weeks) and diabetic insulin-treated group (5 U insulin /day). Ovarian sections were stained with hematoxylin and eosin, Masson's trichrome, immunohistochemistry for VEGF and TGF-β. The diabetic group showed noticeable atrophic and degenerative changes in cortex and medulla as well as increased density and distribution of the collagenous fibers. The number and diameter of primary, secondary and tertiary follicles were decreased. However, the number of atretic follicles and corpus luteum was increased. Significant decrease in the surface area percentage of VEGF immuno-expression and significant increase in TGF-β immuno-expression surface area percentage were detected. By treating animals with metformin and insulin, there was restoration of the ovarian histological structure more or less as in control. DM negatively affects the histological and morphometric parameters of ovaries. Furthermore, insulin showed more beneficial effects than metformin in hindering these complications by modifying the expression of VEGF and TGF-β.

Heterotopic ovarian allotransplantation in goats: Preantral follicle viability and tissue remodeling

An appropriate implantation site favors angiogenesis and avoids ovarian tissue damage after tissue grafting. The objective of this study was to evaluate the effects of intramuscular (IM) and subcutaneous (SC) sites for ovarian grafts in goats by evaluating follicular morphology and activation, preantral follicle and stromal cell densities, tissue DNA fragmentation, collagen types I and III depositions, and graft revascularizations. Ovarian cortical tissue was transplanted in IM or SC sites and recovered 7 or 15 days post-transplantation. There was a greater percentage of developing follicles and lesser follicular and stromal cell densities in all grafted tissues as compared to ovarian tissues of the control group. The stromal cell density and percentage of normal follicles were positively associated. At 15 days post-transplantation, tissues at the SC and IM sites had similar amounts of DNA fragmentation and type III collagen content. In contrast, tissues at the SC, as compared with IM site, had greater abundances of collagen type I. Furthermore, there was a positive association between collagen type I and percentage of morphologically normal follicles post-transplantation. In addition to a marked decrease in follicular density 15 days post-transplantation in ovarian grafts at the SC and IM sites, low percentages of normal follicles and follicular activation were observed similarly in both transplantation sites. There were also positive associations of stromal cell density and abundance of type I collagen fibers with the percentage of intact follicles in grafted ovarian tissues.

Effects of Co-Administration of Bone Marrow Stromal Cells and L-Carnitine on The Recovery of Damaged Ovaries by Performing Chemotherapy Model in Rat

Background

L-carnitine (Lc) as a type of flavonoid antioxidants and bone marrow stromal cells (BMSCs) as a type of mesenchymal stem cells may recover damaged ovaries. It seems that Lc has favorable effects on differentiation, increasing lifespan and decreasing apoptosis in BMSCs. The aim of this study was to investigate effects of co-administration of BMSC+Lc on damaged ovaries after creating a chemotherapy model with cyclophosphamide in rats.

Materials and Methods

In this experimental study, cyclophosphamide was intraperitoneally (IP) injected to forty female wistar rats for 14 days, in terms of chemotherapy-induced ovarian destruction. The rats were then randomly divided into four groups: control, Lc, BMSCs and co-administration of BMSC+Lc. Injection of BMSCs into bilateral ovaries and intraperitoneal injection of Lc were performed individually and together. Four weeks later, levels of serum estradiol (E2) and follicle-stimulating hormone (FSH) using enzyme-linked immunosorbent assay (ELISA) kit, number of ovarian follicles at different stages using hematoxylin and eosin (H and E) staining and expression of ovarian Bcl-2 and Bax proteins using western blot were assessed.

Results

Co-administration of BMSC+Lc increased E2 and decreased FSH levels compared to the control group (P<0.001). The number of follicles was higher in the co-administrated group compared to the control group (P<0.001). Co-administration of BMSC+Lc increased Bcl-2 protein level, decreased Bax protein level and increased Bcl-2/Bax ratio (P<0.001).

Conclusion

The effect of co-administration of BMSC+Lc is probably more effective than the effect of their separate administration on the recovery of damaged ovaries by chemotherapy.

Bone Marrow Stromal Cells with the Granulocyte Colony-Stimulating Factor in the Management of Chemotherapy-Induced Ovarian Failure in a Rat Model

BACKGROUND

Bone marrow stromal cells (BMSCs), as a type of mesenchymal stem cells, and the granulocyte colony-stimulating factor (G-CSF), as a type of growth factor, may recover damaged ovaries. The aim of the present study was to investigate the effects of the coadministration of BMSCs and the G-CSF on damaged ovaries after creating a chemotherapy model with cyclophosphamide (CTX) in rats.

METHODS

The present study was performed in Semnan, Iran, in the late 2016 and the early 2017. BMSCs were cultured and were confirmed using the CD markers of stromal cells. Forty female Wistar rats were randomly divided into 4 groups. The rats were injected intraperitoneally with CTX for 14 days to induce chemotherapy and ovarian destruction. Then, the BMSCs were injected into bilateral ovaries and the G-CSF was injected intraperitoneally, individually and together. Four weeks later, the number of ovarian follicles using H&E staining, the number of apoptotic granulosa cells using the TUNEL assay, the number of produced oocytes from the ovaries, and the levels of serum E2 and FSH using an ELISA reader were assessed. Statistical analysis was done using one-way ANOVA with SPSS, version 16.0.

RESULTS

The results showed that the effects of the coadministration of 2×10⁶ BMSCs and 70 µg/kg of the G-CSF were significantly more favorable than those in the control group (P<0.001), the BMSC group (P=0.016), and the G-CSF group (P<0.001) on the recovery of damaged ovaries.

CONCLUSION

The efficacy of the coadministration of BMSCs and the G-CSF in the recovery of ovaries damaged by chemotherapy was high by comparison with the administration of either of them separately.

Evaluation of Z-VAD-FMK as an anti-apoptotic drug to prevent granulosa cell apoptosis and follicular death after human ovarian tissue transplantation

PURPOSE

To evaluate the efficiency of ovarian tissue treatment with Z-VAD-FMK, a broad-spectrum caspase inhibitor, to prevent follicle loss induced by ischemia/reperfusion injury after transplantation.

METHODS

In vitro, granulosa cells were exposed to hypoxic conditions, reproducing early ischemia after ovarian tissue transplantation, and treated with Z-VAD-FMK (50 μM). In vivo, cryopreserved human ovarian fragments (n = 39) were embedded in a collagen matrix containing or not Z-VAD-FMK (50 μM) and xenotransplanted on SCID mice ovaries for 3 days or 3 weeks.

RESULTS

In vitro, Z-VAD-FMK maintained the metabolic activity of granulosa cells, reduced HGL5 cell death, and decreased PARP cleavage. In vivo, no improvement of follicular pool and global tissue preservation was observed with Z-VAD-FMK in ovarian tissue recovered 3-days post-grafting. Conversely, after 3 weeks of transplantation, the primary follicular density was higher in fragments treated with Z-VAD-FMK. This improvement was associated with a decreased percentage of apoptosis in the tissue.

CONCLUSIONS

In situ administration of Z-VAD-FMK slightly improves primary follicular preservation and reduces global apoptosis after 3 weeks of transplantation. Data presented herein will help to guide further researches towards a combined approach targeting multiple cell death pathways, angiogenesis stimulation, and follicular recruitment inhibition.

Organ culture of seminiferous tubules using a modified soft agar culture system

BACKGROUND

In-vitro spermatogenesis in mammalian species is considered an important topic in reproductive biology. New strategies for achieving a complete version of spermatogenesis ex vivo have been conducted using an organ culture method or culture of testicular cells in a three-dimensional soft agar culture system (SACS). The aim of this study was to develop a new method that supports spermatogenesis to the meiotic phase and morphologically mature spermatozoa through the culture of testicular cells and seminiferous tubules (STs) in a modified SACS, respectively.

METHODS

First, enzymatically dissociated testicular cells and mechanically dissociated STs of neonatal mice were separately embedded in agarose and then placed on the flat surface of agarose gel half-soaked in the medium to continue culture with a gas-liquid interphase method.

RESULTS

Following 40 days of culture, the meiotic (Scp3) and post-meiotic (Acr) gene expression in aggregates and STs was confirmed by real-time polymerase chain reaction. These results were complemented by immunohistochemistry. The presence of morphologically mature spermatozoa in the frozen sections of STs was demonstrated with hematoxylin and eosin staining. We observed Plzf- or Integrin α6-positive spermatogonia in both cultures after 40 days, indicating the potency of the culture system for both self-renewal and differentiation.

CONCLUSIONS

This technique can be used as a valuable approach for performing research on spermatogenesis and translating it into the human clinical setting.

Angiopoietin-1 and -2 and vascular endothelial growth factor expression in ovarian grafts after cryopreservation using two methods

Objective

The favored method of preserving fertility in young female cancer survivors is cryopreservation and autotransplantation of ovarian tissue. Reducing hypoxia until angiogenesis takes place is essential for the survival of transplanted ovarian tissue. The aim of this study was to investigate the role of angiopoietin-1 (Angpt-1), angiopoietin-2 (Angpt-2), and vascular endothelial growth factor (VEGF) in ovarian tissue grafts that were cryopreserved using two methods.

Methods

Ovarian tissues harvested from ICR mice were divided into three groups: group I (control), no cryopreservation; group II, vitrification in EFS (ethylene-glycol, ficoll, and sucrose solution)-40; and group III, slow freezing in dimethyl sulfoxide. We extracted mRNA for VEGF, Angpt-1, and Angpt-2 from ovarian tissue 1 week following cryopreservation and again 2 weeks after autotransplantation. We used reverse transcriptase-polymerase chain reaction to quantify the levels of VEGF, Angpt-1, and Angpt-2 in the tissue.

Results

Angpt-1 and Angpt-2 expression decreased after cryopreservation in groups II and III. After autotransplantation, Angpt-1 and Angpt-2 expression in ovarian tissue showed different trends. Angpt-1 expression in groups II and III was lower than in group I, but Angpt-2 in groups II and III showed no significant difference from group I. The vitrified ovarian tissues had higher expression of VEGF and Angpt-2 than the slowfrozen ovarian tissues, but the difference was not statistically significant.

Conclusion

Our results indicate that Angpt-2 may play an important role in ovarian tissue transplantation after cryopreservation although further studies are needed to understand its exact function.

Effect of sustained release of basic fibroblast growth factor using biodegradable gelatin hydrogels on frozen-thawed human ovarian tissue in a xenograft model

AIM

Ovarian tissue cryopreservation before cancer treatment is the only option to preserve fertility under some circumstances. However, tissue ischemia after transplantation while awaiting angiogenesis induces dysfunctional folliculogenesis and reduces ovarian reserve and is one of the disadvantages of frozen-thawed ovarian tissue transplantation. Basic fibroblast growth factor (bFGF) is a major regulator of angiogenesis. However, bFGF rapidly loses biological activity when its free form is injected in vivo. This study investigated whether administration of active bFGF helps establish a nurturing environment for follicular survival.

METHODS

A sheet form of a sustained release drug delivery system for bFGF was developed using biodegradable acidic gelatin hydrogel (bFGF sheet). The bFGF sheets or phosphate-buffered saline sheets, as a negative control, were transplanted with frozen-thawed human ovarian tissues subcutaneously into the backs of severe combined immunodeficient mice. Neovascularization, cell proliferation, fibrosis and follicular survival of ovarian grafts were analyzed at 6 weeks after xenografting.

RESULTS

The bFGF sheets were optimized to release bFGF for at least 10 days. The transplantation of bFGF sheets with frozen-thawed ovarian tissues significantly increased human and mouse CD31-positive areas and stromal and endothelial cell proliferations. The administration of bFGF also significantly decreased the percentage of the fibrotic area in the graft, resulting in a significant increase in primordial and primary follicular density.

CONCLUSION

Local administration of a sustained release of biologically active bFGF induced neovascularization in frozen-thawed ovarian tissue grafts, which could establish the nurturing environment required for follicular survival in heterotopic xenografts.

Effect of Transplantation of Bone Marrow Stromal Cell- Conditioned Medium on Ovarian Function, Morphology and Cell Death in Cyclophosphamide-Treated Rats

Objective

Although stem cell transplantation has beneficial effects on tissue regeneration, but there are still problems such as high cost and safety issues. Since stem cell therapy is largely dependent on paracrine activity, in this study, utilization of transplantation of bone marrow stromal cells (BMSCs)-secretome instead of the cells, into damaged ovaries was evaluated to overcome the limitations of stem cell transplantation.

Materials and Methods

In this experimental study, BMSCs were cultured and 25-fold concentrated conditioned medium (CM) from BMSCs was prepared. Female rats were injected intraperitoneally with cyclophosphamide (CTX) for 14 days. Then, BMSCs and CM were individually transplanted into bilateral ovaries, and the ovaries were excised after four weeks of treatment. The follicle count was performed using hematoxylin and eosin (H&E) staining and the apoptotic cells were counted using TUNEL assay. Ovarian function was evaluated by monitoring the ability of ovulation and the levels of serum estradiol (E₂) and follicle-stimulating hormone (FSH).

Results

Evaluation of the ovarian function and structure showed that results of secretome transplantation were almost similar to those of BMSCs transplantation and there was no significant differences between them.

Conclusion

BMSCs-secretome is likely responsible for the therapeutic paracrine effect of BMSCs. Stem cell- secretome is expected to overcome the limitations of stem cell transplantation and become the basis of a novel therapy for ovarian damage.

Effect of treatment with angiopoietin-2 and vascular endothelial growth factor on the quality of xenografted bovine ovarian tissue in mice

Cryopreservation and transplantation of ovarian tissue (OT) represents a method for fertility preservation. However, as the transplantation is performed without vessel anastomosis, unavoidable ischemic damage occurs. To reduce this ischemic damage and improve outcomes after transplantation, we used two kind of angiogenic factors, angiopoietin-2 (ang-2) and vascular endothelial growth factor (VEGF). Fresh or vitrified-warmed bovine OTs were prepared for xenotransplantation (XT). Fresh OTs were immediately xenografted into nude mice (XT-Fresh). Vitrified-warmed OTs were xenografted into four subgroups of mice, which were injected intraperitoneally before XT with saline (XT-Vitri), Ang-2 (XT-Ang-2), VEGF (XT-VEGF), and a combination of Ang-2 and VEGF (XT-Combined). Seven or 28 days post-grafting, grafted OTs and blood samples were collected for evaluation. Follicle normality was higher in the angiogenic factor-treated groups than in the XT-Vitri group. The XT-VEGF and the XT-Combined showed higher (P<0.05) follicular density than the XT-Vitri group. The highest apoptotic follicle ratio was observed in the XT-Vitri group on day 7; this was decreased (P<0.05) in the XT-Combined group. Microvessel densities were higher in the angiogenic factor-treated groups than in the XT-Vitri group. The largest fibrotic area was showed in the XT-Vitri group on day 28, and it was decreased (P<0.05) in the XT-combined group. Based on these results, administration of Ang-2 and VEGF to recipients prior to XT appeared to alleviate ischemic damage by enhancing angiogenesis, which resulted in the maintenance of follicle integrity and density, and reduced follicle apoptosis and OT fibrosis.

Expectations and limitations of ovarian tissue transplantation

Constant progress in the diagnosis and treatment of cancer disease has increased the number and prognosis of cancer survivors. However, the toxic effects of chemotherapy and radiotherapy on ovarian function have resulted in premature ovarian failure. Patients are, therefore, still expecting methods to be developed to preserve their fertility successfully. Several potential options are available to preserve fertility in patients who face premature ovarian failure, including immature or mature oocyte and embryo cryopreservation. However, for children or prepubertal women needing immediate chemotherapy, cryopreservation of ovarian tissue is the only alternative. The ultimate aim of this strategy is to implant ovarian tissue into the pelvic cavity (orthotopic site) or in a heterotopic site once oncological treatment is completed and the patient is disease free. Transplantation of ovarian tissue with sufficiently large numbers of follicles could potentially restore endocrine function and allow multiple cycles for conception. However, the success of ovarian tissue transplantation still has multiple challenges, such as the low number of follicles in the graft that may affect their longevity as well as the survival of the tissue during ex vivo processing and subsequent transplantation. Therefore, this review aims to summarize the achievements of ovary grafting and the potential techniques that have been developed to improve ovarian graft survival.

Ovarian Fibrosis: A Phenomenon of Concern

Objective:

Ovarian fibrosis is characterized by excessive proliferation of ovarian fibroblasts and deposition of extracellular matrix (ECM) and it is one of the principal reasons for ovarian dysfunction. This review aimed to investigate the pathogenetic mechanism of ovarian fibrosis and to clarify the relationship between ovarian diseases and fibrosis.

Data Sources:

We searched PubMed for English language articles published up to November 2016. The search terms included ovarian fibrosis OR fibrosis, ovarian chocolate cyst OR ovarian endometrioma, polycystic ovarian syndrome (PCOS), premature ovarian failure, ECM, matrix metalloproteinases (MMPs), tissue inhibitors of matrix metalloproteinases (TIMPs), transforming growth factor-beta 1 (TGF-β1), connective tissue growth factor (CTGF), peroxisome proliferator-activated receptor gamma (PPAR-γ), vascular endothelial growth factor (VEGF), endothelin-1 (ET-1), and combinations of these terms.

Study Selection:

Articles were obtained and reviewed to analyze the pathogenic mechanism of ovarian fibrosis and related ovarian diseases.

Results:

Many cytokines, such as MMPs, TIMPs, TGF-β1, CTGF, PPAR-γ, VEGF, and ET-1, are involved in ovarian fibrogenesis. Ovarian fibrogenesis is associated with various ovarian diseases, including ovarian chocolate cyst, PCOS, and premature ovarian failure. One finding of particular interest is that fibrogenesis in peripheral tissues around an ovarian chocolate cyst commonly causes ovarian function diminution, and therefore, this medical problem should arouse widespread concern in clinicians worldwide.

Conclusions:

Patients with ovarian fibrosis are susceptible to infertility and tend to have decreased responses to assisted fertility treatment. Thus, protection of ovarian function should be a priority for women who wish to reproduce when making therapeutic decisions about ovarian fibrosis-related diseases.

Effects of Angiopoietin-2 on Transplanted Mouse Ovarian Tissue

Transplantation of ovarian tissue (OT) is currently the only clinical option to restore fertility with cryopreserved OT. However, follicle loss caused by ischemia and slow revascularization occurs in transplanted OT. To shorten the ischemic period and promote angiogenesis, some angiogenic factors have been used. Angiopoietin-2 (Ang2) is one of the major angiogenic factors and has been reported to promote blood vessels and increase vascular permeability in ischemic and/or hypoxic environment. This study was performed to investigate the effects of Ang2 on follicle integrity and revascularization of transplanted mouse OT. Five-week-old B6D2F1 female mice were divided into a control group and two Ang2 groups, followed by ovary collection and vitrification. After warming, the ovaries were autotransplanted into kidney capsules with/without Ang2 injection (50 or 500 ng/kg), and then the mice were sacrificed at days 2, 7, 21, and 42 after transplantation. A total 2,437 follicles in OT grafts were assessed for follicular density, integrity, and classification by using hematoxylin and eosin staining. Apoptosis and revascularization were evaluated by using TUNEL assay and CD31 immunohistochemistry, respectively. Serum follicle-stimulating hormone (FSH) levels were measured by using enzyme-linked immunosorbent assay. Both Ang2 groups showed remarkable increase in morphologically intact follicle ratio across all grafting durations except D21. The numbers of CD31(+) vessels were significantly increased in both Ang2 groups compared with the control group at all durations, except in the 50 ng Ang2 group at D42. However, the mean numbers of follicles of the grafts, apoptosis ratios, and serum FSH levels showed no significant differences among the groups. Our results show that Ang2 treatment significantly increased the intact follicle ratios and the number of blood vessels of the mouse OT grafts. However, further studies performed with large animal or human OT are necessary before clinical application for fertility preservation in cancer patients, and the reliability of the systemic effects of Ang2 should be verified.

Hyaluronic acid-based hydrogel scaffold without angiogenic growth factors enhances ovarian tissue function after autotransplantation in rats

One of the problems encountered during ovarian transplantation is that the number of primordial follicles in the grafts is considerably reduced 2 d after transplantation due to post-transplantation ischemia. This study investigates if the use of hyaluronic acid-based hydrogel (HABH) with and without vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) could prevent or minimize ischemia-induced follicle loss during ovarian autotransplantation and thereby restore ovarian tissue function in the rat model. In this study, twenty four female rats were subjected to bilateral ovariectomy and were randomly divided into 3 groups for ovarian tissue autotransplantation. Group A included rats with ovarian tissue without HABH, VEGF and bFGF, group B comprised rats with ovarian tissue encapsulated with HABH and group C had rats with ovarian tissue encapsulated with HABH containing VEGF and bFGF. Three days after transplantation, the grafts were assessed through histological and hormonal analyses. Apoptotic, angiogenic and maturation genes expressions were also analyzed. The mean number of follicles in all developmental stages increased in group B (P  <  0.05). The level of FSH decreased in group B (P  <  0.05) whereas, the expression level of VEGF gene increased in group B (P  <  0.05). No significant changes were observed in the expression levels of maturation and apoptotic genes in all groups. In conclusion, ovarian encapsulation with HABH alone can prevent or minimize ischemia-induced follicle loss, preserve the follicular pool, promote follicular survival, facilitate angiogenesis, and restore hormone levels. However, its efficiency in a clinical setting and in comparison with other hydrogels needs further investigation.

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.

Ovarian injury during cryopreservation and transplantation in mice: a comparative study between cryoinjury and ischemic injury

STUDY QUESTION

What is the main cause of ovarian injury during cryopreservation and transplantation in mice: cryoinjury or ischemic injury?

SUMMARY ANSWER

Post-transplantation ischemia is the main cause of ovarian injury during cryopreservation and transplantation for restoring ovarian function.

WHAT IS KNOWN ALREADY

During cryopreservation and the transplantation of ovaries, cryoinjury and ischemic injury inevitably occur, which has a detrimental effect on ovarian quality and reserve.

STUDY DESIGN, SIZE, DURATION

A total of 80 B6D2F1 female mice were randomly allocated to 2 control and 6 experimental groups according to the presence or the absence of transplantation (n = 10/group). The control groups consisted of fresh or vitrified-warmed controls that had the whole ovary fixed without transplantation (fresh and vitri-con, respectively). The experimental groups were further divided according to the presence of vitrification (fresh or vitrified-warmed) and the transplantation period (2 [D2], 7 [D7] or 21 [D21] days).

PARTICIPANTS/MATERIALS, SETTING, METHODS

In the control groups, fresh and vitrified-warmed ovaries were immediately fixed after the collection (fresh) and the vitrification-warming process (vitrification control, vitri-con), respectively. Of those experimental groups, three were auto-transplanted with fresh whole ovary (FrOT; FrOT-D2, FrOT-D7 and FrOT-D21). For the other three groups, the ovaries were harvested and stored in liquid nitrogen for 1 week after vitrification and then warmed to auto-transplant the vitrified whole ovaries (vitrified ovary [VtOT]; VtOT-D2, VtOT-D7 and VtOT-D21). After 2, 7 or 21 days of grafting, the grafts and blood sera were collected for analysis by hematoxylin-eosin staining, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, CD31 immunohistochemistry and follicle-stimulating hormone enzyme-linked immunosorbent assay.

MAIN RESULTS AND THE ROLE OF CHANCE

The vitrification-warming procedure decreased the proportion of intact follicles (Grade 1, G1) (vitri-con 50.3% versus fresh 64.2%) but there was a larger decrease due to ischemic injury after transplantation (FrOT-D2: 42.5%). The percentage of apoptotic follicles was significantly increased in the vitrified-warmed ovary group compared with the fresh control, but it increased more after transplantation without vitrification (fresh: 0.9%, vitri-con: 6.0% and FrOT-D2: 26.8%). The mean number of follicles per section and percentage of CD31-positive area significantly decreased after vitrification but decreased to a larger extent after transplantation (number of follicles, fresh: 30.3 ± 3.6, vitri-con: 20.6 ± 2.9, FrOT-D2: 17.9 ± 2.1; CD31-positive area, fresh: 10.6 ± 1.3%, vitri-con: 5.7 ± 0.9% and FrOT-D2: 4.2 ± 0.4%). Regarding the G1 follicle ratio and CD31-positive area per graft, only the FrOT groups significantly recovered with time after transplantation (G1 follicle ratio, FrOT-D2: 42.5%, FrOT-D7: 56.1% and FrOT-D21: 70.7%; CD31-positive area, FrOT-D2: 4.2 ± 0.4%, FrOT-D7: 5.4 ± 0.6% and FrOT-D21: 7.5 ± 0.8%). Although there was no significant difference between the two transplantation groups at each evaluation, the serum follicle-stimulating hormone level of both groups significantly decreased over time.

LIMITATIONS AND REASONS FOR CAUTION

It is unclear how far these results can be extrapolated from mice to the human ovary.

WIDER IMPLICATIONS OF THE FINDINGS

Minimizing ischemic injury should be the first priority rather than preventing cryoinjury alone, and decreasing the combination of cryoinjury and ischemic injury is necessary to improve ovarian quality after cryopreservation and transplantation.

STUDY FUNDING/COMPETING INTEREST

This study was supported by a grant of the Korea Healthcare Technology R&D Project, Ministry of Health & Welfare, Republic of Korea (HI12C0055). The authors have no conflict of interest to declare.

bFGF and VEGF improve the quality of vitrified-thawed human ovarian tissues after xenotransplantation to SCID mice

PURPOSE

The aim of this research is to study whether basic fibroblast growth factor (bFGF) alone or in combination with vascular endothelial growth factor (VEGF) could improve the quality of vitrified-thawed human ovarian tissue xenotransplanted to severe combined immune deficiency (SCID) mice.

METHODS

After collection and cryopreservation, thawed human ovarian tissue were cultured in vitro for 2 days and then xenografted to severe combined immune deficiency (SCID) mice for 7 days. The in vitro culture medium was separated into six groups, including (A) the blank control group, (B) the human recombinant bFGF (150 ng/ml) group, (C) the bFGF (150 ng/ml)+human recombinant VEGF (25 ng/ml) group, (D) bFGF (150 ng/ml)+VEGF (50 ng/ml) group, (E) bFGF (150 ng/ml)+ VEGF (75 ng/ml) group and (F) bFGF (150 ng/ml) + VEGF (100 ng/ml) group. In addition, eight pieces of thawed ovarian tissue were transplanted without in vitro culture, which serve as the fresh control group. The effect of transplantation was assessed by histological analysis, immunohistochemical staining for CD34, Ki-67, and AC-3 expression, and microvessel density (MVD).

RESULTS

There was no significant difference between the fresh and blank control group. Compared to the blank control group, the number of follicles, MVD, and rate of Ki-67-positive cells increased significantly in groups B, C, D, E, and F, while apoptosis decreased significantly. Compared to the bFGF treatment group, no significant difference appeared in group C, D, E, and F.

CONCLUSIONS

The administration of bFGF alone or in combination with VEGF improved the quality of postgraft human ovarian tissue, though VEGF, regardless of different concentrations, did not influence effect of bFGF.

In vitro evaluation of the anti-apoptotic drug Z-VAD-FMK on human ovarian granulosa cell lines for further use in ovarian tissue transplantation

PURPOSE

Because ovarian granulosa cells are essential for oocyte survival, we examined three human granulosa cell lines as models to evaluate the ability of the pan-caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-FMK) to prevent primordial follicle loss after ovarian tissue transplantation.

METHODS

To validate the efficacy of Z-VAD-FMK, three human granulosa cell lines (GC1a, HGL5, COV434) were treated for 48 h with etoposide (50 μg/ml) and/or Z-VAD-FMK (50 μM) under normoxic conditions. To mimic the ischemic phase that occurs after ovarian fragment transplantation, cells were cultured without serum under hypoxia (1 % O(2)) and treated with Z-VAD-FMK. The metabolic activity of the cells was evaluated by WST-1 assay. Cell viability was determined by FACS analyses. The expression of apoptosis-related molecules was assessed by RT-qPCR and Western blot analyses.

RESULTS

Our assessment of metabolic activity and FACS analyses in the normoxic experiments indicate that Z-VAD-FMK protects granulosa cells from etoposide-induced cell death. When cells are exposed to hypoxia and serum starvation, their metabolic activity is reduced. However, Z-VAD-FMK does not provide a protective effect. In the hypoxic experiments, the number of viable cells was not modulated, and we did not observe any modifications in the expressions of apoptosis-related molecules (p53, Bax, Bcl-xl, and poly (ADP-ribose) polymerase (PARP)).

CONCLUSION

The death of granulosa cell lines was not induced in our ischemic model. Therefore, a protective effect of Z-VAD-FMK in vitro for further use in ovarian tissue transplantation could not be directly confirmed. It will be of interest to potentially use Z-VAD-FMK in vivo in xenograft models.

A combination of simvastatin and methylprednisolone improves the quality of vitrified-warmed ovarian tissue after auto-transplantation

STUDY QUESTION

Does the preoperative administration of simvastatin and methylprednisolone enhance mouse ovarian quality after auto-transplantation of vitrified-warmed ovarian tissue (OT)?

SUMMARY ANSWER

Treatment with combined simvastatin and methylprednisolone enhances the quality of transplanted mouse OTs.

WHAT IS KNOWN ALREADY

The prevention of ischemic injury after transplantation of OT is critical for preserving the ovarian follicles. Preoperative administration of simvastatin (a cholesterol-lowering drug) has beneficial effects on various organ transplantations. Moreover, donor treatment with simvastatin and methylprednisolone (main effects are on immune response) prevents ischemia-reperfusion injury and has a beneficial effect on allograft survival in rat cardiac allografts.

STUDY DESIGN, SIZE, DURATION

A total of 232 6-week-old B6D2F1 mice were randomly distributed into fresh control, vitrified-warmed control and experimental groups (n = 10-17 per group). The experimental groups were as follows: sham control, simvastatin, methylprednisolone and co-treatment groups. In the experimental groups, the mice were administered simvastatin (5 mg/kg, orally), methylprednisolone (15 mg/kg, i.v.) or a combination of simvastatin and methylprednisolone 2 h before ovariectomy, whereas the sham control mice received normal saline.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Whole ovaries were removed from the mice and vitrified by two-step vitrification procedures. The vitrified ovaries were warmed 1 week later and auto-transplanted under the bilateral kidney capsules. The ovaries and blood samples were collected 2, 7 and 21 days (D) after transplantation for histological analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, immunohistochemistry for CD31 and serum anti-Mullerian hormone (AMH) level estimation. Embryonic development was evaluated after IVF of oocytes obtained from the transplanted ovary.

MAIN RESULTS AND THE ROLE OF CHANCE

The group that received simvastatin and methylprednisolone showed a significantly improved intact (Grade 1) follicle ratio (D2: P < 0.001, D7: P < 0.05 and D21: P < 0.001), apoptotic follicle ratio (D21: P < 0.05), CD31-positive area (D7: P < 0.05 and D21: P < 0.05) and serum AMH level (D7: P < 0.001) after transplantation when compared with the sham control. However, no difference was noted in the fertilization and blastocyst formation rates, number of total and apoptotic blastomeres per blastocyst and inner cell mass/trophectoderm ratio among the four transplantation groups.

LIMITATIONS, REASONS FOR CAUTION

Although we evaluated the beneficial effects of simvastatin and methylprednisolone in the present study, we did not unravel the corresponding protective mechanisms.

WIDER IMPLICATIONS OF THE FINDINGS

Our results suggest that a combination of simvastatin and methylprednisolone has beneficial effects on the quality and functioning of transplanted OT. This combined treatment can potentially be applied clinically to humans and domestic animals subject to further studies.

Effect of Local Basic Fibroblast Growth Factor and Vascular Endothelial Growth Factor on Subcutaneously Allotransplanted Ovarian Tissue in Ovariectomized Mice

Objective

One of the major obstacles to ovarian tissue preservation is delayed angiogenesis that leads follicles lost after transplantation. The aim of the present study was to investigate the effects of bFGF and VEGF on heterotopic transplanted ovarian tissue using a mouse model.

Methods

Female mice underwent bilateral ovariectomy. Ovarian tissues encapsulated by fibrin hydrogels were transplanted subcutaneously into recipient mice, in which ovarian hormonal cyclicity was absent. The fibrinogen solution was mixed with bFGF, VEGF, or a mixture of bFGF and VEGF. The grafts were recovered 21 days after transplantation. Follicle morphology and follicle numbers were observed by H&E staining. Blood vessels were observed in transplanted intra-ovarian tissue by CD31 antibody IHC staining. Daily vaginal cytology was performed to determine estrous cycle and functional restoration of transplanted ovarian tissue. Blood was collected weekly and serum FSH levels were measured with a radioimmunoassay kit. Apoptosis analysis was performed by anti-AC-3 staining and survivin mRNA expression.

Results

The number of primordial follicles and secondary follicles in the bFGF+VEGF group was significantly higher than in the control group. The vascular density in the bFGF+VEGF groups were significantly higher than in the bFGF and the VEGF groups; there was no significant difference between the bFGF and VEGF groups. Estrous cycle was earlier in the bFGF+VEGF group compared with the control group; all mice in this group restored ovarian function. Serum FSH levels in the bFGF+VEGF group were significantly lower than in the control group by day 14 post-transplantation. The AC-3-positive in control group was significantly higher compared with bFGF group and VEGF group, and in bFGF+VEGF group was significantly lower than bFGF group and VEGF group. Survivin mRNA expression in bFGF+VEGF group was significantly higher than control group.

Conclusion

The combination of bFGF and VEGF has beneficial effects on follicle survival, angiogenesis, and resumption of estrous cycles.

Trolox enhances follicular survival after ovarian tissue autograft in squirrel monkey (Saimiri collinsi)

The aim of this study was to evaluate ovarian tissue pre-treatment with 50 µM Trolox followed by heterotopic transplantation in squirrel monkeys (Saimiri collinsi) and to assess tissue functionality via immunohistochemical analysis of the stroma and ovarian follicles. Five healthy and sexually mature squirrel monkey (Saimiri collinsi) females were used. Heterotopic autografting of fresh ovarian tissue with or without previous exposure to the antioxidant Trolox was performed and grafts were recovered for analysis 7 days later. Tissue vascularisation was confirmed by both macroscopic inspection and cluster of differentiation 31 (CD31) staining. Trolox prevented massive follicular activation and kept the percentages of morphologically normal follicles higher than in untreated grafts. Expression of anti-Müllerian hormone in developing follicles was observed only in controls and Trolox-treated grafts. Also, immunostaining for growth differentiation factor-9 was positive only in primordial follicles from controls and from Trolox-treated grafts. Although Trolox improved follicular quality and avoided apoptosis in stromal cells, ovarian tissue fibrosis was increased in Trolox-treated grafts, mainly due to an increase in collagen Type I synthesis.

Isoform 165 of vascular endothelial growth factor in collagen matrix improves ovine cryopreserved ovarian tissue revascularisation after xenotransplantation in mice

BACKGROUND

Aggressive anti-cancer treatments can result in ovarian failure. Ovarian cryopreservation has been developed to preserve the fertility of young women, but early graft revascularisation still requires improvement.

METHODS

Frozen/thawed sheep ovarian cortical biopsies were embedded in collagen matrix with or without isoform 165 of vascular endothelial growth factor (VEGF165) and transplanted into ovaries of immunodeficient mice. Ovaries were chosen as transplantation sites to more closely resemble clinical conditions in which orthotopic transplantation has previously allowed several spontaneous pregnancies.

RESULTS

We found that VEGF165 significantly increased the number of Dextran-FITC positive functional vessels 3 days after grafting. Dextran- fluorescein isothiocyanate (FITC) positive vessels were detectable in 53% and 29% of the mice in the VEGF-treated and control groups, respectively. Among these positive fragments, 50% in the treated group displayed mature smooth-muscle-actin-alpha (alpha-SMA) positive functional vessels compared with 0% in the control group. CD31 positive murine blood vessels were observed in 40% of the VEGF165 transplants compared with 21% of the controls. After 3 weeks, the density of murine vessels was significantly higher in the VEGF165 group.

CONCLUSION

The encapsulation of ovarian tissue in collagen matrix in the presence of VEGF165 before grafting has a positive effect on functional blood vessel recruitment. It can be considered as a useful technique to be improved and further developed before human clinical applications in female cancer patients in the context of fertility preservation.

Effect of preoperative simvastatin treatment on transplantation of cryopreserved-warmed mouse ovarian tissue quality

After the ovarian tissue (OT) transplantation, the ischemia-reperfusion injury causes depletion and apoptosis of follicle. Recent reports stated that simvastatin reduces ischemic damage. Therefore, we used the mouse whole ovarian vitrification and autotransplantation models to investigate the effects of simvastatin. Five-week-old B6D2F1 mice were randomly divided into four groups. Three groups were given simvastatin orally (5 mg/kg) before ovariectomy, either 2 hours before (2H Tx) or once a day for 3 or 7 days. The control group was given saline 2 hours before ovariectomy. All ovaries were cryopreserved by vitrification, held in liquid nitrogen for 1 week before being warmed, and autotransplanted. The grafts were collected for analysis on 2, 7, or 21 days after transplantation. Ovarian follicle morphology and apoptosis were assessed by hematoxylin and eosin staining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Vessel integrity in ovary was evaluated by immunohistochemistry using anti-CD31 antibody. Serum FSH level was measured to estimate the transplanted ovarian reserve. The proportion of morphologically normal (G1) follicles at 7 and 21 days and the percentage of CD31 (+) tissue at 21 days was significantly higher in the 2H Tx group than that in the control group. In addition, the 2H Tx group showed a significantly increased intact primordial follicle ratio at 2 and 21 days after OT transplantation. Administration of simvastatin 2 hours before ovariectomy could improve the quality after transplantation of cryopreserved mouse OT.