Impact of congenital or experimental hypogonadotrophism on the radiation sensitivity of the mouse ovary

Thyroid hormone triiodothyronine does not protect ovarian reserve from DNA damage induced by X-ray and cisplatin

PURPOSE

Cancer therapy can induce premature ovarian insufficiency, necessitating methods for preserving fertility in female cancer patients. However, the only accepted clinical practice for doing so is cryopreservation of embryos, unfertilized ova, and ovarian tissue, despite potential options such as in vitro maturation of follicles. Therefore, considerable interest has arisen in fertoprotective agents, with research on rat ovarian granulosa cells suggesting that triiodothyronine (T3) regulates an anti-apoptosis mechanism that protects the ovarian reserve from paclitaxel-induced DNA damage. In this study, we used postnatal day 5 mouse ovary to confirm the existence of T3 thyroid hormone receptor (THR), as well as to investigate the potential protective effects of T3 against cisplatin- and X-ray-induced apoptosis. We also tested the potential anti-apoptotic effect of T3 in the breast cancer cell line MDA-MB-231.

METHODS

We treated cultured mouse ovaries with varying concentration of T3 and 4 μM cisplatin and 0.2 Gy X-ray. Real-time PCR, histological analysis, immunoblot analysis, and immunofluorescence were performed to assess the potential anti-apoptotic effects of T3.

RESULTS

We confirmed that THR alpha and beta are expressed in the mouse ovary. T3 (0.1, 1, 10, 100 nM, and 1 µM) does not protect ovarian reserve from cisplatin- or X-ray-induced apoptosis or DNA damage. Similarly, it does not protect mouse granulosa cells and MDA-MB-231 cells from cisplatin- or X-ray-induced apoptosis.

CONCLUSION

Our findings suggest that T3 is ineffective as a fertoprotective agent, and its candidacy as a potential agent to preserve fertility should be reconsidered.

Promising anti- cervical carcinoma and inflammatory agent, Resveratrol targets poly (ADP-ribose) polymerase 1 (PARP-1) induced premature ovarian failure with a potent enzymatic modulatory activity

Radioprotective effects of Resveratrol is well known in normal cells exposed to the damaging effects of ionizing radiation however, its potential radioprotective effect on ovarian follicle formation and development is still uncertain. Astonishingly, it has been reported that PARP contributed to the pathogenesis of immune-mediated ovarian injury. In this paper, Resveratrol was tested for its inflammatory, anti-cervical carcinoma activity, and checked its targets poly (ADP-ribose) polymerase 1 (PARP-1) induced premature ovarian failure with a potent enzymatic modulatory activity. Through high-throughput virtual screening method, Resveratrol was screened to find its target. That the compound strongly inhibited cervical carcinoma HT-3 cell. The cell proliferation was evaluated by an CCK-8 assay, and the cell apoptosis was assessed by a flow cytometry. Rat model of premature ovarian failure was used to introduce resveratrol preparation and rtPCR was done to measure expression of apoptosis related markers. We report resveratrol as a potential target for PARP-1 and its modulator from a high-throughput virtual screening method. Resveratrol was measured its anti-cervical carcinoma activity by using an CCK-8 assay, which suggested that the compound strongly inhibited HT-3 cell proliferation, the IC₅₀ value is 0.65 μM. In addition, the compound induced HT-3 cell apoptosis in a dose-response manner. Resveratrol preserves the entire ovarian follicle pool manifested by increasing serum anti-Müllerian hormone (AMH) levels. Study suggest that resveratrol restored ovarian function through increasing AMH levels, and diminishing ovarian inflammation, predominantly modulation of PPAR-1 and inhibition of inflammatory cytokines. Resveratrol was identified targets for PARP-1 from a high-throughput virtual screening method, strongly inhibited PARP-1 protein and HT-3 cell proliferation. Resveratrol is a promising PARP-1 modulator with anti-cervical carcinoma activity, which deserves further investigation.

Effects of Environment and Lifestyle Factors on Premature Ovarian Failure

Premature ovarian insufficiency (POI) or primary ovarian failure is defined as a cessation of the menstrual cycle in women younger than 40 years old. It is strictly defined as more than 4 months of oligomenorrhea or amenorrhea in a woman <40 years old, associated with at least two follicle-stimulating hormone (FSH) levels >25 U/L in the menopausal range, detected more than 4 weeks apart. It is estimated that POI was affected 1 and 2% of women. Although 80% of POI cases are of unknown etiology, it is suggested that genetic disorder, autoimmune origin, toxins, and environmental factors, as well as personal lifestyles, may be risk factors of developing POI. In this section, we will discuss the influences of environmental and lifestyle factors on POI. Moreover updated basic research findings regarding how these environmental factors affect female ovarian function via epigenetic regulations will also be discussed.

Carvacrol and Thymol Modulate the Cross-Talk between TNF-α and IGF-1 Signaling in Radiotherapy-Induced Ovarian Failure

Premature ovarian failure (POF) is a common cause of infertility in premenopausal women who are unavoidably exposed to cytotoxic therapy. Radiotherapy is one of the most effective cytotoxic treatments. However, the radiosensitivity of ovarian tissues limits its therapeutic outcome and results in the depletion of the primordial follicle and loss of fertility. Therefore, the need for an effective radioprotective therapy is evident especially when none of the current clinically used modalities for radioprotection succeeds efficiently. The present study investigated the potential radioprotective effect of carvacrol (CAR) (80 mg) or thymol (80 mg) on gamma- (γ-) irradiation-induced ovarian damage as well as their role in the cross-talk between IGF-1 and TNF-α signaling and antioxidative activity. In immature female Wister rats, a single dose of whole-body irradiation (3.2 Gy, LD₂₀) produced considerable ovarian damage, which was evident by histopathological findings and hormonal changes. Interestingly, pretreatment with CAR or thymol significantly enhanced the follicular development and restored the anti-Mullerian hormone (AMH), E2, and FSH levels. Both essential oils improved the irradiation-mediated oxidative stress and reduction in proliferating cell nuclear antigen (PCNA) expression. Moreover, irradiated rats exhibited an inverse relationship between IGF-1 and TNF-α levels two days post irradiation, which was further inverted by the pretreatment with CAR and thymol and ought to contribute in their radioprotective mechanisms. In conclusion, CAR and thymol showed a radioprotective effect and rescued the ovarian reserve mainly through counteracting oxidative stress and the dysregulated cross-talk between IGF-1 and TNF-α.

Brachytherapy and fertility

Fertility is a major part of the global care of patients treated for cancer. A new discipline known as oncofertility has emerged in some countries. Although the relationship between chemotherapy and external radiotherapy and fertility has been studied and reported, there is only scarce data available on brachytherapy. This systematic review aims to report available knowledge on the impact of brachytherapy on fertility. Specific consultations should be considered before brachytherapy to inform patients about their fertility preservation options.

Resveratrol inhibits inflammatory signaling implicated in ionizing radiation-induced premature ovarian failure through antagonistic crosstalk between silencing information regulator 1 (SIRT1) and poly(ADP-ribose) polymerase 1 (PARP-1)

This study hypothesized that resveratrol, a silencing information regulator 1 (SIRT1) activator, would counteract the inflammatory signaling associated with radiotherapy-induced premature ovarian failure (POF). Immature female Sprague-Dawley rats were subjected to a single dose of γ-radiation to induce POF and treated with resveratrol (25mg/kg) once daily for two weeks before and three days post irradiation. Resveratrol preserves the entire ovarian follicle pool manifested by increasing serum anti-Müllerian hormone (AMH) levels. Radiation triggered inflammatory process in the ovary through enhanced NF-κB and poly(ADP-ribose) polymerase (PARP)-1 expression which convinced the expression of inflammatory markers including IL-6, IL-8, and visfatin mRNA levels, as well as inducible nitric oxide synthase and cyclooxygenase-2 protein expression with a concomitant reduction in IL-10 mRNA levels. Resveratrol significantly counteracted the effect of radiation and upregulated the gene expression of peroxisome proliferator-activated receptor γ (PPAR-γ) and SIRT1. Resveratrol-activated SIRT1 expression was associated with inhibition of PARP-1 and NF-κB expression-mediated inflammatory cytokines. Our findings suggest that resveratrol restored ovarian function through increasing AMH levels, and diminishing ovarian inflammation, predominantly via upregulation of PPAR-γ and SIRT1 expression leading to inhibition of NF-κB provoked inflammatory cytokines.

Growth Hormone Ameliorates the Radiotherapy-Induced Ovarian Follicular Loss in Rats: Impact on Oxidative Stress, Apoptosis and IGF-1/IGF-1R Axis

Radiotherapy is one of the standard cytotoxic therapies for cancer. However, it has a profound impact on ovarian function leading to premature ovarian failure and infertility. Since none of the currently available methods for fertility preservation guarantees future fertility, the need for an effective radioprotective agent is highly intensified. The present study investigated the mechanisms of the potential radioprotective effect of growth hormone (GH) on γ irradiation-induced ovarian failure and the impact of the insulin like growth factor 1 (IGF-1) in the underlying protection. Immature female Sprague-Dawley rats were either exposed to single whole body irradiation (3.2 Gy) and/or treated with GH (1 mg/kg s.c). Experimental γ-irradiation produced an array of ovarian dysfunction that was evident by assessment of hormonal changes, follicular development, proliferation marker (PCNA), oxidative stress as well as apoptotic markers. In addition, IGF-1/IGF-1R axis expression was assessed using real-time PCR and immunolocalization techniques. Furthermore, after full maturity, fertility assessment was performed. GH significantly enhanced follicular development and restored anti-Mullerian hormone serum level as compared with the irradiated group. In addition, GH significantly ameliorated the deleterious effects of irradiation on oxidative status, PCNA and apoptosis. Interestingly, GH was shown to enhance the ovarian IGF-1 at transcription and translation levels, a property that contributes significantly to its radioprotective effect. Finally, GH regained the fertility that was lost following irradiation. In conclusion, GH showed a radioprotective effect and rescued the ovarian reserve through increasing local IGF-1 level and counteracting the oxidative stress-mediated apoptosis.

Folliculogenesis Is Not Fully Inhibited during GnRH Analogues Treatment in Mice Challenging Their Efficiency to Preserve the Ovarian Reserve during Chemotherapy in This Model

As many chemotherapy regimens induce follicular depletion, fertility preservation became a major concern in young cancer patients. By maintaining follicles at the resting stage, gonadotropin-releasing hormone analogues (GnRHa) were proposed as an ovarian-protective option during chemotherapy. However, their efficacy and mechanisms of action remain to be elucidated. Mice were dosed with cyclophosphamide (Cy, 100–500mg/kg i.p) to quantify follicular depletion and evaluate apoptosis at different times. We observed a dose-dependent depletion of the follicular reserve within 24 hours after Cy injection with a mean follicular loss of 45% at the dose of 200mg/kg. Apoptosis occurs in the granulosa cells of growing follicles within 12 hours after Cy treatment, while no apoptosis was detected in resting follicles suggesting that chemotherapy acutely affects both resting and growing follicles through different mechanisms. We further tested the ability of both GnRH agonist and antagonist to inhibit oestrus cycles, follicular growth and FSH secretion in mice and to protect ovarian reserve against chemotherapy. Although GnRHa were efficient to disrupt oestrus cycles, they failed to inhibit follicular development, irrespective of the doses and injection sites (sc or im). Around 20% of healthy growing follicles were still observed during GnRHa treatment and serum FSH levels were not reduced either by antagonist or agonist. GnRHa had no effect on Cy-induced follicular damages. Thus, we showed that GnRHa were not as efficient at inhibiting the pituitary-gonadal axis in mice as in human. Furthermore, the acute depletion of primordial follicles observed after chemotherapy does not support the hypothesis that the ovary may be protected by gonadotropin suppression.

Fertility preservation during cancer treatment: clinical guidelines

The majority of children, adolescents, and young adults diagnosed with cancer today will become long-term survivors. The threat to fertility that cancer treatments pose to young patients cannot be prevented in many cases, and thus research into methods for fertility preservation is developing, aiming at offering cancer patients the ability to have biologically related children in the future. This paper discusses the current status of fertility preservation methods when infertility risks are related to surgical oncologic treatments, radiation therapy, or chemotherapy. Several scientific groups and societies have developed consensus documents and guidelines for fertility preservation. Decisions about fertility and imminent potentially gonadotoxic therapies must be made rapidly. Timely and complete information on the impact of cancer treatment on fertility and fertility preservation options should be presented to all patients when a cancer treatment is planned.

Fertility issues in cancer survivorship

Breakthroughs in cancer diagnosis and treatment have led to dramatic improvements in survival and the need to focus on survivorship issues. Chemotherapy and radiotherapy can be gonadotoxic, resulting in impaired fertility. Techniques to help cancer survivors reproduce have been improving over the past decade. Discussion of the changes to a patient's reproductive health after cancer treatment is essential to providing comprehensive quality care. The purpose of this review is to aid in pre- and posttreatment counseling, focusing on fertility preservation and other strategies that may mitigate risks to the patient's reproductive, sexual, and overall health.

Human amniotic epithelial cells can differentiate into granulosa cells and restore folliculogenesis in a mouse model of chemotherapy-induced premature ovarian failure

INTRODUCTION

Ovarian dysfunction frequently occurs in female cancer patients after chemotherapy, but human amniotic epithelial cells (hAECs) that can differentiate into cell types that arise from all three germ layers may offer promise for restoration of such dysfunction. Previous studies confirmed that hAECs could differentiate into cells that express germ cell-specific markers, but at this time hAECs have not been shown to restore ovarian function.

METHODS

To model premature ovarian failure, hAECs infected with lenti-virus carrying green fluorescent protein were injected into the tail vein of mice sterilized with cyclophosphamide and busulphan. hAECs migrated to the mouse ovaries and overall ovarian function was measured using immunohistochemical techniques.

RESULTS

Seven days to two months after hAECs transplantation, ovarian cells were morphologically restored in sterilized mice. Hemotoxylin and eosin staining revealed that restored ovarian cells developed follicles at all stages. No follicles were observed in control mice at the same time period. Immunostaining with anti-human antigen antibodies and pre-transplantation labeling with green fluorescent protein (GFP) revealed that the grafted hAECs survived and migrated to mouse ovary, differentiating into granulosa cells. Furthermore, the ovarian function marker, anti-Müllerian hormone, was evident in treated mouse ovaries after hAEC transplantation.

CONCLUSIONS

Intravenously injected hAECs reached the ovaries of chemotherapy-treated mice and restored folliculogenesis, data which suggest promise for hAECs for promoting reproductive health and improving the quality of life for female cancer survivors.

Insights into the protective mechanisms of tamoxifen in radiotherapy-induced ovarian follicular loss: impact on insulin-like growth factor 1

Radiotherapy is one of the most common and effective cancer treatments. However, it has a profound impact on ovarian function, leading to premature ovarian failure. With the hope of preserving fertility in cancer survivors, the need for an effective radioprotective therapy is evident. The present study investigated the mechanism of the potential radioprotective effect of tamoxifen (TAM) on γ-irradiation-induced ovarian failure on experimental rats and the impact of the IGF-1 in the underlying protective mechanisms. Female Sprague Dawley rats were either exposed to single whole-body irradiation (3.2 Gy; lethal dose [LD₂₀]) and/or treated with TAM (1 mg/kg). γ-Irradiation caused an array of ovarian dysfunction that was evident by assessment of hormonal changes, follicular development, proliferation marker (proliferating cell nuclear antigen), and oxidative stress as well as apoptotic markers. In addition, IGF-1/IGF-1 receptor axis expression was assessed using real-time RT-PCR and immunolocalization techniques. Furthermore, fertility assessment was performed. TAM significantly enhanced follicular development and restored the anti-Mullerian hormone level. Moreover, it ameliorated the deleterious effects of irradiation on oxidative stress, proliferating cell nuclear antigen expression, and apoptosis. Interestingly, TAM was shown to enhance the ovarian IGF-1 but not IGF-1 receptor, a property that contributed significantly to its radioprotective mechanisms. Finally, TAM regained the fertility that was lost after irradiation. In conclusion, TAM showed a radioprotective effect and saved the ovarian reserve and fertility through increasing anti-Mullerian hormone and the local IGF-1 level and counteracting the oxidative stress-mediated apoptosis.

ICRP publication 118: ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs--threshold doses for tissue reactions in a radiation protection context

This report provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. It was instigated following a recommendation in Publication 103 (ICRP, 2007), and it provides updated estimates of 'practical' threshold doses for tissue injury defined at the level of 1% incidence. Estimates are given for morbidity and mortality endpoints in all organ systems following acute, fractionated, or chronic exposure. The organ systems comprise the haematopoietic, immune, reproductive, circulatory, respiratory, musculoskeletal, endocrine, and nervous systems; the digestive and urinary tracts; the skin; and the eye. Particular attention is paid to circulatory disease and cataracts because of recent evidence of higher incidences of injury than expected after lower doses; hence, threshold doses appear to be lower than previously considered. This is largely because of the increasing incidences with increasing times after exposure. In the context of protection, it is the threshold doses for very long follow-up times that are the most relevant for workers and the public; for example, the atomic bomb survivors with 40-50years of follow-up. Radiotherapy data generally apply for shorter follow-up times because of competing causes of death in cancer patients, and hence the risks of radiation-induced circulatory disease at those earlier times are lower. A variety of biological response modifiers have been used to help reduce late reactions in many tissues. These include antioxidants, radical scavengers, inhibitors of apoptosis, anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, growth factors, and cytokines. In many cases, these give dose modification factors of 1.1-1.2, and in a few cases 1.5-2, indicating the potential for increasing threshold doses in known exposure cases. In contrast, there are agents that enhance radiation responses, notably other cytotoxic agents such as antimetabolites, alkylating agents, anti-angiogenic drugs, and antibiotics, as well as genetic and comorbidity factors. Most tissues show a sparing effect of dose fractionation, so that total doses for a given endpoint are higher if the dose is fractionated rather than when given as a single dose. However, for reactions manifesting very late after low total doses, particularly for cataracts and circulatory disease, it appears that the rate of dose delivery does not modify the low incidence. This implies that the injury in these cases and at these low dose levels is caused by single-hit irreparable-type events. For these two tissues, a threshold dose of 0.5Gy is proposed herein for practical purposes, irrespective of the rate of dose delivery, and future studies may elucidate this judgement further.

Fertility preservation in female cancer patients

With improved survival rates among cancer patients, fertility preservation is now being recognized as an issue of great importance. There are currently several methods of fertility preservation available in female cancer patients and the options and techniques via assisted reproduction and cryopreservation are increasing, but some are still experimental and continues to be evaluated. The established means of preserving fertility include embryo cryopreservation, gonadal shielding during radiation therapy, ovarian transposition, conservative gynecologic surgery such as radical trachelectomy, donor embryos/oocytes, gestational surrogacy, and adoption. The experimental methods include oocyte cryopreservation, ovarian cryopreservation and transplantation, in vitro maturation, and ovarian suppression. With advances in methods for the preservation of fertility, providing information about risk of infertility and possible options of fertility preservation to all young patients with cancer, and discussing future fertility with them should be also considered as one of the important parts of consultation at the time of cancer diagnosis.

Options on fertility preservation in female cancer patients

Infertility following treatment of cancer is a quality of survival's recognized issue and efforts should be made to help young cancer patients retaining their fertility potential. Options to preserve fertility in female patients include well established methods such as shielding to reduce radiation damage to reproductive organs, fertility-sparing surgery and emergency in vitro fertilization after controlled ovarian stimulation, aiming at freezing embryos. Transfer of frozen/thawed embryos today is a clinical routine in fertility clinics worldwide and it has been used for over 25 years. Mature oocytes after ovarian stimulation can also be frozen unfertilized, nevertheless overall pregnancy rates after fertilization of frozen-thawn oocytes are still relatively lower than those with embryo freezing. Remaining fertility preservation options are still in development and include the freezing of immature oocytes aiming at later in vitro maturing and fertilizing them and the cryopreservation of ovarian tissue for future retransplantation or for in vitro growth and maturation of follicles, both still experimental.

Fertility sparing in cancer patients

Infertility can arise as a consequence of treatment of oncological conditions. As cancer survival rates continue to improve, many women will face infertility after successful treatment of their malignant diseases. This review summarizes the current state of different fertility preservation options in these patients. This review will discuss the premature ovarian failure and other adverse reproductive outcomes in female patients who receive chemotherapy and radiation. In addition, cancer-specific fertility preservation methods are presented. Embryo cryopreservation is a well established technique to preserve fertility. However, it requires delaying cancer treatment for two to six weeks and a partner or willingness to use donor sperm. When these criteria cannot be met, more experimental options include oocyte cryopreservation for later IVF and ovarian tissue cryopreservation. In-vitro maturation is a promising technology and can be applied in combination with oocyte or ovarian tissue cryopreservation. Ovarian transposition remains the standard option for women undergoing pelvic radiation. Lastly, the efficacy of GnRH analoga in ovarian protection during chemotherapy has still not been proved. As fertility preservation choices include both established and experimental methods, a highly individualized approach is required in the management of patients looking for fertility preservation options.

Children born after autotransplantation of cryopreserved ovarian tissue. a review of 13 live births

INTRODUCTION. Premature ovarian failure (POF) can occur naturally at an early age or be due to iatrogenic agents. Indeed, ovaries are very sensitive to cytotoxic treatment, especially to radiation and alkylating agents. METHODS. Several options are currently available to preserve fertility in cancer patients and allow them to conceive when they have overcome their disease: embryo cryopreservation, oocyte cryopreservation, and ovarian tissue cryopreservation. Cryopreservation of ovarian tissue is the only option available for pre-pubertal girls and women who cannot delay the start of chemotherapy. FINDINGS. Since the first live birth after autotransplantation of cryopreserved ovarian tissue in humans was reported in 2004, orthotopic reimplantation has led to the birth of 13 healthy babies. Restoration of ovarian activity and prognostic factors are evaluated by comparison with 7 cases of fresh ovarian tissue transplantation. We report 13 live births after orthotopic transplantation of frozen-thawed ovarian tissue in cancer patients (n = 8) and in patients treated with high doses of chemotherapy for benign diseases (n = 2) (microscopic polyangiitis, sickle cell anemia). INTERPRETATION. Based on our review, we believe that ovarian cortex cryopreservation, associated or not with cryopreservation of immature oocytes, should be offered before gonadotoxic chemotherapy in all cases where there is a high risk of POF and where emergency IVF is not possible.

Fertility preservation medicine: options for young adults and children with cancer

As cancer survival rates continue to improve, many young adults and children will face infertility after successful treatment of their malignant diseases. Fertility is now recognized as a critical component of quality-of-life for cancer survivors and fertility preservation is an emerging discipline that addresses the need for improving cancer survivors' options to have children later in life. Fertility preservation by established methods is often possible in adult female and male cancer patients before starting their gonadotoxic treatments. In prepubertal children, options are still experimental and most challenging. Embryos, oocytes, sperm, or gonadal tissue (ovarian and testicular) can be cryopreserved and stored at subzero temperatures until the time when the patients are disease-free and wish to start a family. As fertility preservation choices include both established and experimental techniques, a highly individualized approach is required in the management of those patients looking for fertility preservation options.

Prevention of premature ovarian failure and osteoporosis induced by irradiation using allogeneic ovarian/bone marrow transplantation

BACKGROUND

Two side effects of irradiation are premature ovarian failure (POF) and osteoporosis, both of which are concerns not only clinically, for patients, but also experimentally, for animals. We examine whether bone marrow transplantation (BMT) can correct the POF induced by radiation and also address whether allogeneic ovarian transplantation (OT) can modulate the adverse effects of radiotherapy.

METHODS

Eight-week-old female C57BL/6 mice were lethally irradiated with 6 Gy x2, and then injected with allogeneic bone marrow cells into their bone marrow cavity using our previously described intrabone marrow (IBM)-BMT technique. Allogeneic ovaries were simultaneously transplanted under the renal capsules of the mice.

RESULTS

Three months after the transplantation, we noted that hematopoietic and lymphoid cells had been successfully reconstituted. The ovaries transplanted under the renal capsules demonstrated signs of development with a large number of differentiating follicles at different stages of development. Importantly, the total bone mineral density of the tibia in the "IBM-BMT+OT" (BMT/OT) group remained normal. However, the reproductive function of the recipient mice was not restored, despite the presence of many immature oocytes in the host ovaries in the BMT/OT group. In the BMT group, no oocytes were found in the host ovaries.

CONCLUSIONS

These findings suggest that IBM-BMT with ovarian allografts can be advantageous for young women with POF and osteopenia or osteoporosis that is due to chemotherapy and radiotherapy for malignant diseases.

The GnRH analogue triptorelin confers ovarian radio-protection to adult female rats

There is a controversy regarding the effects of the analogues of the gonadotrophin-releasing hormone (GnRH) in radiotherapy. This has led us to study the possible radio-protection of the ovarian function of a GnRH agonist analogue (GnRHa), triptorelin, in adult, female rats (Rattus norvegicus sp.). The effects of the X-irradiation on the oocytes of ovarian primordial follicles, with and without GnRHa treatment, were compared, directly in the female rats (F(0)) with reproductive parameters, and in the somatic cells of the resulting foetuses (F(1)) with cytogenetical parameters. In order to do this, the ovaries and uteri from 82 females were extracted for the reproductive analysis and 236 foetuses were obtained for cytogenetical analysis. The cytogenetical study was based on the data from 22,151 metaphases analysed. The cytogenetical parameters analysed to assess the existence of chromosomal instability were the number of aberrant metaphases (2234) and the number (2854) and type of structural chromosomal aberrations, including gaps and breaks. Concerning the reproductive analysis of the ovaries and the uteri, the parameters analysed were the number of corpora lutea, implantations, implantation losses and foetuses. Triptorelin confers radio-protection of the ovaries in front of chromosomal instability, which is different, with respect to the single and fractioned dose. The cytogenetical analysis shows a general decrease in most of the parameters of the triptorelin-treated groups, with respect to their controls, and some of these differences were considered to be statistically significant. The reproductive analysis indicates that there is also radio-protection by the agonist, although minor to the cytogenetical one. Only some of the analysed parameters show a statistically significant decrease in the triptorelin-treated groups.

Preserving female fertility following cancer treatment: current options and future possibilities

Children and women of reproductive age are increasingly surviving cancer diagnoses, and therefore long-term quality-of-life issues are of greater importance at the time of diagnosis. Cancer therapies including radiation and chemotherapy can be detrimental to fertility, and therefore many patients are motivated to preserve fertility prior to cancer treatment. The only highly successful method in preserving fertility to date is embryo cryopreservation, which may not be appropriate for some patients due to age, delay in treatment, cancer type and stage, as well as availability of an acceptable sperm donor. Alternative methods including oocyte cryopreservation and ovarian tissue banking may also preserve fertility while providing additional flexibility to patients. In vitro ovarian follicle maturation following tissue banking is one potential approach that would not require a delay in cancer therapy for ovarian stimulation, would not require an immediate sperm donor, and does not carry the risk of reintroducing malignant cells following tissue transplantation. In vitro follicle culture systems have resulted in successful live births in the mouse. However, many challenges must be addressed in translating the system to the human. This review summarizes current approaches to fertility preservation and discusses recent developments and future challenges in developing a human in vitro follicle culture system.

Clinical aspects of fertility preservation in female patients

There are several methods of fertility preservation available for female patients facing infertility following gonadotoxic treatment of cancer or systemic disease. Embryos, oocytes or ovarian tissue can be cryopreserved and stored until the time when the patient is cured of her main disease and is expecting parenthood. The individual's choice depends on the nature and stage of the main disease, expected treatment, their condition, and age and existence of the partner. It is important to inform all such women about the options, and together with them, choose the most appropriate ones. It is often possible to save ovarian tissue even though the first chemotherapy courses have been undergone, but many more follicles can be stored before cancer treatment.

Normal ovarian function and assessment of ovarian reserve in the survivor of childhood cancer

Increasingly young people survive cancer in childhood and as a result complications of its treatment are becoming more common and important. Premature ovarian failure is recognized as a complication of radiotherapy to a field that includes the pelvis and alkylating-agent-based chemotherapy. Young pre-pubertal girls are not protected from the effects of gonadal toxic therapy. A young woman, successfully treated for cancer during childhood, may experience regular periods in the presence of a significantly reduced ovarian reserve. There is, however, no reliable measure of ovarian reserve available for the individual woman. Assessment of ovarian function relies on the use of surrogate markers such as follicle stimulating hormone, inhibin-B, and anti-mullerian hormone as well as ultrasound assessment of ovarian volume and antral follicle count. We discuss the physiology of normal ovarian function, the effects of cancer treatments on ovarian function and the techniques for evaluation of ovarian reserve in survivors of childhood cancer.

Chemotherapy-induced female infertility and protective action of gonadotropin-releasing hormone analogues

This review aimed to critically discuss the current protocols using gonadotropin-releasing hormone analogue (GnRHa) for the management of chemotherapy-induced premature ovarian failure. In in-vitro experiments, GnRHa retards doxorubicin-induced granulosa cell damage, suggesting an additional GnRH's activity to protect the gonads during chemotherapy through GnRH receptor-mediated mechanism(s). GnRHa acts to protect the gonads during radiation and/or chemotherapy by preferentially steering cells into cell cycle arrest with a decline in response to the chemotherapeutic agents. The ovarian protection by GnRHa co-treatment against chemotherapy can enable the preservation of future fertility in survivors and prevent the bone demineralisation and osteoporosis associated with hypooestrogenism and ovarian failure.

Fertility preservation in female cancer survivors

The advancement of cancer therapies over the last few decades has significantly improved long-term survival of cancer patients, especially children and adolescents. As many of the therapeutic agents used are highly cytotoxic, cancer survivors have to pay the price of enduring various immediate and long-term side-effects. Unfortunately, gonadal failure and infertility are among the most common long-term side-effects, resulting in distress, lowered self-esteem and quality of life. Three modalities of fertility preservation can be offered to female patients prior to commencing their cancer treatment: embryo, oocyte and ovarian tissue cryopreservation. This paper reviews the outcomes for female patients who underwent fertility preservation in University College Hospital between 1995 and 2005, and post-therapeutic use of their frozen specimens. In addition, the effects of cytotoxic agents on fertility and ovarian function, and the range of fertility preservation available for female cancer sufferers are also discussed.

Cancer and fertility preservation in females: where we stand and where we are heading

It is estimated that, in 2010, one in every 250 adults will be a childhood cancer survivor. This review discusses the impact of current cancer treatment on fertility potential and the assisted-reproduction innovations available today for the most common cancers in young women. As the emerging discipline of fertility preservation is steadily attracting increasing interest, developments in the near future promise to be very exciting. However, in everyday routine work, better interdisciplinary cooperation between gynecological and pediatric oncologists, surgeons, immunologists and endocrinologists is necessary so that individualized options for fertility preservation can be offered in advance of surgical procedures or cancer treatments.

Assisted reproduction and fertility preservation techniques in cancer patients

PURPOSE OF REVIEW

This study aims to review the current state of different fertility preservation options in patients facing the risk of gonadal failure.

RECENT FINDINGS

Various malignant and nonmalignant diseases have been successfully treated with high-dose chemotherapy or radiotherapy. Even though many young patients receiving these treatments are at risk of developing reproductive failure, a number of fertility preservation options ranging from embryo cryopreservation to ovarian tissue cryopreservation are now available.

SUMMARY

Embryo cryopreservation is a well established technique to preserve fertility. The success rate with oocyte cryopreservation has been on the rise. Both oocyte and embryo freezing require ovarian stimulation and novel ovarian stimulation regimens utilizing aromatase inhibitors which have been developed for ovarian stimulation in women with estrogen sensitive cancer. Even though ovarian tissue cryopreservation is a novel technology, it is the only fertility preservation option for children and the only treatment strategy that can restore ovarian function. In-vitro maturation is a promising technology and can be applied in combination with ovarian tissue cryopreservation.

Assessment of ovarian reserve following ovarian tissue banking and/or GnRH-a co-treatment prior to chemotherapy in patients with Hodgkin's disease

PURPOSE

To examine ovarian reserve following chemotherapy in women with Hodgkin's disease.

METHODS

The study included nine patients who underwent ovarian tissue cryopreservation (OTCP) prior to chemotherapy consisting of the ABVD regimen (Adriamycin, bleomycin, vinblastine, and dacarbazine) and co-treatment with gonadotropin-releasing hormone agonist (GnRH-a) (Group A), and 13 patients treated by the ABVD protocol only without GnRH-a (Group B). The average age was 25.2 +/- 2.7 years for the women in Group A and 31.8 +/- 6.8 years for those in Group B.

RESULTS

Six months following the end of chemotherapy, the menstrual cycle resumed in all Group A patients and in four Group B patients who had amenorrhea. Eight Group B patients had regular menses during and after chemotherapy. None of the patients suffered from ovarian failure. Two Group A patients conceived in the first year after completing chemotherapy.

CONCLUSIONS

Co-treatment with GnRH-a has little effect on ovarian protection in women with Hodgkin's disease.

Fertility issues of childhood cancer survivors: the role of the pediatric nurse practitioner in fertility preservation

The purpose of this review is to discuss the role of the pediatric nurse practitioner (PNP) surrounding the survivorship issue of infertility. The author outlines the effects of treatment, examines available options, explores ethical and legal issues, discusses the role of the PNP, and addresses areas of further research. The issue of postcancer reproductive health is increasing in importance as both the number of cancer survivors and length of survival increases. Approximately 1 out of every 900 individuals in the United States between the ages of 15 and 45 years is a survivor of childhood cancer. In fact, the survival rates for childhood cancer have improved dramatically. Sexual function and fertility in children and adolescents has become a prominent issue, and this review illustrates the gap between care providers and patients and describes how PNPs must fill this gap to manage the adverse effects on fertility and gonadal dysfunction.

Hormonal suppression for fertility preservation in males and females

Methods to restore fertility of men and women sterilized by medical treatments and environmental toxicant exposures are under investigation. Rendering spermatogenesis and ovarian follicular development kinetically quiescent by suppression of gonadotropins has been proposed to protect them from damage by cytotoxic therapy. Although the method fails to protect the fertility of male mice and monkeys, gonadotropin and testosterone suppression in rats before or after cytotoxic therapy do enhance the recovery of spermatogenesis. However, the mechanism involves not the induction of quiescence but rather the reversal, by suppression of testosterone, of a block in differentiation of surviving spermatogonia caused by damage to the somatic environment. In men, only one of eight clinical trials was successful in protecting or restoring spermatogenesis after cytotoxic therapy. In women, protection of primordial follicles in several species from damage by cytotoxic agents using GnRH analogs has been claimed; however, only two studies in mice appear convincing. The protection cannot involve the induction of quiescence in the already dormant primordial follicle but may involve direct effects of GnRH analogs or indirect effects of gonadotropin suppression on the whole ovary. Although numerous studies in female patients undergoing chemotherapy indicate that GnRH analogs might be protective of ovarian function, none of the studies showing protection were prospective randomized clinical trials and thus they are inconclusive. Considering interspecies differences and similarities in the gonadal sensitivity to cytotoxic agents and hormones, mechanistic studies are needed to identify the specific beneficial effects of hormonal suppression in select animal models that may be applicable to humans.

Absence of conclusive evidence for the safety and efficacy of gonadotropin-releasing hormone analogue treatment in protecting against chemotherapy-induced gonadal injury

Every year, an increasing number of women with malignant and nonmalignant diseases is successfully treated with cytotoxic chemotherapy and/or radiotherapy. Many of these patients suffer from infertility and gonadal failure as a result of these treatments. At present, these patients may resort to assisted-reproduction techniques to protect their future childbearing potential before the implementation of cytotoxic therapy. While embryo cryopreservation is an established technology, oocyte and ovarian tissue freezing techniques are still investigational. Nevertheless both of these techniques have resulted in live births. Apart from assisted-reproduction techniques, it has been extensively debated whether administration of gonadotropin-releasing hormone (GnRH) analogues in conjunction with chemotherapy can protect ovarian reserve against cytotoxic insult. In this manuscript, we debate the rationale for the effectiveness of GnRH analogue coadministration in preservation of fertility by reviewing the literature, and provide preliminary data to support our views.

Fertility preservation options for women with malignancies

Cancer is not rare in younger women. There has been a remarkable improvement in the survival rates due to progress in cancer treatment. The necessary treatment for most of the common cancer types occurring in younger women implies either removal of the reproductive organs or cytotoxic treatment that could partially or definitively affect reproductive function. Early loss of ovarian function not only puts the patients at risk for menopause-related complications at a very young age, but is also associated with loss of fertility. Further, women in the western hemisphere have been delaying initiation of childbearing to later in life. The results of these changes have led to an increase in patients facing the risk of premature ovarian failure, and therefore seeking help in preserving their fertility. This increase in demand has resulted in a proliferation of techniques to preserve fertility. Indeed, the number of options is increasing; some are more established procedures, such as embryo cryopreservation, and some are still experimental, such as ovarian cryopreservation. Because of the variations in type and dose of chemotherapy, the type of cancer, the time available before onset of treatment, the patient's age and the partner status, each case is unique and requires a different strategy of fertility preservation.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to recall the potential early loss of ovarian function secondary to radiotherapy and/or chemotherapy for cancer at a young age; explain the increasing demands for fertility preservation; and summarize the limited number of proven, safe, and efficacious methods.

Successful pregnancies after transplantation of frozen–thawed mouse ovaries into chimeric mice that received lethal-dose radiation

OBJECTIVE

To study whether fecundity was recovered in mice into which umbilical cord blood cells (UCBCs) were transfused after lethal-dose radiation, followed by transplantation of frozen-thawed ovaries.

DESIGN

Prospective basic research study.

SETTING

Academic research laboratory.

ANIMAL(S)

Female C57BL/6 mice as recipients of UCBCs and ovaries, male B6C3F1 mice for mating, and green fluorescent protein (GFP)-transgenic mice: 18.5-day-old fetuses (-/+) for UCBCs and adult GFP mice (+/+) for ovarian tissues.

INTERVENTION(S)

The UCBCs were transfused into each irradiated mouse, with GFP+ ovaries transplanted 4 weeks later. The chimeric mice were mated 3 weeks after ovarian transplantation and were examined 14 to 16 weeks after the transfusion of UCBCs.

MAIN OUTCOME MEASURE(S)

Percentage of chimerism, number of GFP+ pups.

RESULT(S)

The percentage of chimerism in these mice tends to increase with the radiation dose. The recovery of fecundity was observed in the chimeric mice that were transplanted with fresh and previously vitrified ovaries after exposure to radiation.

CONCLUSION(S)

Even when the exposure dose of radiation administered as pretreatment is lethal, the fecundity of recipients can be maintained if their ovaries are cryopreserved before they are exposed to radiation.

The effect of cancer treatment on female fertility and strategies for preserving fertility

Aggressive chemotherapy and radiotherapy in young patients with cancer has greatly enhanced the life expectancy of these patients, but these treatments often cause infertility because of the massive destruction of the ovarian reserve resulting in premature ovarian failure (POF). This review focuses on the effect of cancer treatments on fertility and on the various surgical and assisted-reproduction innovations that are available to provide the patient with the option of future pregnancies. As the emerging discipline of fertility preservation is steadily attracting increasing interest, developments in the near future promise to be very exciting. However, in everyday routine work, better interdisciplinary cooperation between gynecological and pediatric oncologists, surgeons, immunologists and endocrinologists is necessary so that individualized options for fertility preservation can be offered in advance of surgical procedures or cancer treatments. GnRH analog treatment can preserve fertility in some patients, but not in all. At present, cryopreservation of ovarian tissue appears as a very promising method of providing the cancer patient with a realistic chance of preserving fertility-a prospect that is also extremely important to patients for psychological reasons.

Gonadal damage and options for fertility preservation in female and male cancer survivors

It is estimated that in 2010, 1 in every 250 adults will be a childhood cancer survivor. Today, oncological surgery, radiotherapy and chemotherapy achieve relatively high rates of remission and long-term survival, yet are often detrimental to fertility. Quality of life is increasingly important to long-term survivors of cancer, and one of the major quality-of-life issues is the ability to produce and raise normal children. Developments in the near future in the emerging field of fertility preservation in cancer survivors promise to be very exciting. This article reviews the published literature, discusses the effects of cancer treatment on fertility and presents the options available today thanks to advances in assisted-reproduction technology for maintaining fertility in male and female patients undergoing this type of treatment. The various diagnostic methods of assessing the fertility potential and the efficacy of in vitro fertilization (IVF) after cancer treatment are also presented.

Fertility preservation in cancer patients

Fertility preservation is an important but often neglected need of cancer patients. There are several options available but many are considered experimental or are unproven. Most require interventions that can postpone the initiation of cancer treatment. The options include surgical procedures to move the ovaries out of the path of a radiation field, prophylactic medical therapy with gonadotropin-releasing hormone agonists and storage of gametes, embryos or gonadal tissue. Embryo freezing after conventional in vitro fertilization has a high success rate. Experimental fertility preservation procedures such as oocyte freezing and ovarian tissue cryopreservation/transplantation should be offered to cancer patients only under institutional review board oversight. Laparoscopic ovarian transposition is a viable option if radiotherapy is to be used alone. Oncologists, reproductive endocrinologists and other healthcare professionals should be part of a multidisciplinary team that offers cancer patients options to preserve their reproductive potential if they desire to do so.

Fertility preservation in female cancer patients: current developments and future directions

OBJECTIVE

To review the current advances in fertility preservation strategies and to discuss future directions with an emphasis on ovarian tissue cryobanking.

DESIGN

The publications related to fertility preservation in cancer patients were identified through Medline and other bibliographic databases, focusing on the most recent developments.

CONCLUSION(S)

There are several options for fertility preservation in cancer patients. Even though most of them are still experimental and their efficacy and reliability have not been determined, the future of fertility preservation in women with cancer is promising. In particular, the recent report of a live birth after transplantation of human ovarian tissue has reinforced the clinical potential of ovarian tissue banking for fertility preservation. Many exciting studies are underway to improve the efficacy and solve the problems with current fertility preservation strategies. It is inevitable that we will see the emergence of more complex ethical problems with the application of new technologies to humans. However, continuous efforts to improve current strategies and to develop new strategies will benefit many women and children who are facing premature ovarian failure and sterility.

Subfertility in children and young people treated for solid and haematological malignancies

Children treated for cancer may exhibit impaired fertility in later life. A number of chemotherapeutic agents have been identified as being gonadotoxic, and certain treatment regimens are particularly associated with subsequent infertility. Radiotherapy can also cause gonadal damage, most notably after direct testicular or pelvic irradiation or following total body irradiation. Because of the varied nature of the cytotoxic insult, it can be difficult to predict the likelihood of infertility in later life. Currently, cryopreservation of spermatozoa, oocytes or embryos is the only method of preserving fertility in patients receiving gonadotoxic therapy. This is only applicable to postpubertal patients and can be problematic in the adolescent age group. At present there is no provision for the prepubertal child, although there are a number of experimental methods being investigated. However, in addition to the many scientific and technical issues to be overcome before clinical application of such techniques, a number of ethical and legal issues must also be addressed to ensure a safe and realistic prospect for future fertility in these patients.