Ovarian tissue and oocyte cryopreservation

Mouse oocyte vitrification with and without dimethyl sulfoxide: influence on cryo-survival, development, and maternal imprinted gene expression

PURPOSE

Oocytes and embryos can be vitrified with and without dimethyl sulfoxide (DMSO). Objectives were to compare no vitrification (No-Vitr), vitrification with DMSO (Vitr + DMSO), and vitrification without DMSO (Vitr - DMSO) on fresh/warmed oocyte survival, induced parthenogenetic activation, parthenogenetic embryo development, and embryonic maternal imprinted gene expression.

METHODS

In this prospective controlled laboratory study, mature B6C3F1 female mouse metaphase II oocytes were treated as: i) No-Vitr, ii) Vitr + DMSO/warmed, and iii) Vitr - DMSO/warmed with subsequent parthenogenetic activation and culture to the blastocyst stage. Oocyte cryo-survival, parthenogenetic activation and embryo development, parthenogenetic embryo maternal imprinted gene expression were outcome measures.

RESULTS

Oocyte cryo-survival was significantly improved in Vitr + DMSO versus Vitr - DMSO at initial warming and 2 h after warming. Induced parthenogenetic activation was similar between all three intervention groups. While early preimplantation parthenogenetic embryo development was similar between control, Vitr + DMSO, Vitr - DMSO oocytes, the development to blastocysts was significantly inferior in the Vitr - DMSO oocytes group compared to the control and Vitr + DMSO oocyte groups. Finally, maternal imprinted gene expression was similar between intervention groups at both the 2-cell and blastocyst parthenogenetic embryo stage.

CONCLUSION(S)

Inclusion of DMSO in oocyte vitrification solutions improved cryo-survival and developmental potential of parthenogenetic embryos to the blastocyst stage without significantly altering maternal imprinted gene expression.

VEGF and FGF2 Improve Revascularization, Survival, and Oocyte Quality of Cryopreserved, Subcutaneously-Transplanted Mouse Ovarian Tissues

This study was conducted to investigate the effect of the vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2) on revascularization, survival, and oocyte quality of cryopreserved, subcutaneously-transplanted mouse ovarian tissue. Autologous subcutaneous transplantation of vitrified-thawed mouse ovarian tissues treated with (experimental group) or without (control group) VEGF and FGF2 was performed. After transplantation to the inguinal region for two or three weeks, graft survival, angiogenesis, follicle development, and oocyte quality were examined after gonadotropin administration. VEGF coupled with FGF2 (VEGF/FGF2) promoted revascularization and significantly increased the survival rate of subcutaneously-transplanted cryopreserved ovarian tissues compared with untreated controls. The two growth factors did not show long-term effects on the ovarian grafts. In contrast to the untreated ovarian grafts, active folliculogenesis was revealed as the number of follicles at various stages and of mature oocytes in antral follicles after gonadotropin administration were remarkably higher in the VEGF/FGF2-treated groups. Although the fertilization rate was similar between the VEGF/FGF2 and control groups, the oocyte quality was much better in the VEGF/FGF2-treated grafts as demonstrated by the higher ratio of blastocyst development. Introducing angiogenic factors, such as VEGF and FGF2, may be a promising strategy to improve revascularization, survival, and oocyte quality of cryopreserved, subcutaneously-transplanted mouse ovarian tissue.

Fertility preservation in reproductive-age women facing gonadotoxic treatments

BACKGROUND

Advancements in the treatments for cancer and autoimmune and other hematologic conditions continue to improve survival and cure rates. Despite those changes, various gonadotoxic agents and other treatments can still compromise the future fertility of many women. Progress in medical and surgical reproductive technologies has helped to offset the reproductive consequences of the use of gonadotoxic therapies, and allows for future fertility and normal pregnancy.

METHODS

A review of the literature was performed to outline the pathophysiology of gonadotoxicity from various treatments. The success of fertility preservation, fertility sparing, and cryopreservation options are reviewed. Barriers and facilitators to referral and oncofertility treatment in Canada are also outlined.

RESULTS

According to the quality of the evidence, recommendations are made for fertility assessment, patient referral, cryopreservation, and other assisted reproductive technologies.

CONCLUSIONS

To ensure ongoing fertility in women undergoing gonadotoxic treatments, assisted reproductive technologies can be combined with a multidisciplinary approach to patient assessment and referral.

Knowledge, attitudes, and practices of hematologists regarding fertility preservation in Turkey

Objective: Fertility preservation stands before us as an issue of quality of life for cancer patients and their partners and families. Therefore, the object of the present study was to determine the extent of the knowledge that hematologists have about fertility preservation and to understand their attitudes and practices regarding this matter.


Materials and Methods: A total of 25 hematologists participated in a survey. The questionnaire included questions on sociodemographic characteristics and awareness concerning the subject of fertility preservation, as well as questions designed to determine the extent of the knowledge that hematologists had on the subject and to understand their attitudes and practices in this context.

Results: Of the participants in the study, all expressed their awareness of the adverse effects that the various treatments they were prescribing could have on fertility; 2 (8%) revealed that they had never heard of the concept of fertility preservation. Of the participants, 19 (76%) indicated that they did not have adequate knowledge about fertility preservation, but 22 (88%) fortunately expressed a need for acquiring more knowledge about the subject. Of the respondents, 23 (92%) said that they did not have any brochures or published resources on this subject and stated their belief that if hematologists did have such documents, they would have more opportunity to discuss the various fertility preservation options with patients. All of the participants in the survey supported the idea of the Turkish Society of Hematology publishing a guidebook on this subject and organizing a session on fertility preservation in their regular congress.

Conclusion: Meeting the needs of hematologists for training and knowledge in the subject of fertility preservation and ensuring the development of appropriate attitudes and practices in this area is an important issue. The Turkish Society of Hematology may play a significant key role.

Conflict of interest:None declared.

Is vitrification of oocytes useful for fertility preservation for age-related fertility decline and in cancer patients?

The aim of this review is to provide current knowledge on oocyte cryopreservation, with special emphasis on vitrification as a means to preserve fertility in different indications. Major advancements achieved in the past few years in the cryolaboratory have facilitated major changes in our practice. Areas such as fertility preservation for social or oncologic reasons, the possibility to create oocyte banks for egg donation programs, the opportunity to avoid ovarian hyperstimulation syndrome, or to accumulate oocytes in low-yield patients, or even to offer treatment segmentation by stimulating the ovaries, vitrifying, and then transferring in a natural cycle are some of the options that are now available with the development of cryopreservation. We present general experience from our group and others on fertility preservation for age-related fertility decline as well as in oncologic patients, confirming that oocyte vitrification is a standardized, simple, reproducible, and efficient option.

Preservation of Fertility in Female Cancer Patients Desiring Future Child Bearing; What is Available and What can be Offered

The aim of this review is to present an overview of available methods for preservation of ovarian function and fertility in female cancer patients who desire to maintain their child-bearing capacity for future pregnancies. A Medline search was conducted. Published articles from American and European studies from 1976 to present were reviewed. The effect of cancer treatment on the ovary, as well as different methods of fertility preservation and their reproductive outcomes are presented. Pregnancy rates vary according to the type of primary malignancy, stage of disease, method of fertility preservation (for example, hormonal therapy, cryopreservation, fertility-sparing surgery), and other confounding factors such as the patient's age, reproductive capacity, status of partnership, and genetic disposition. The highest rates of successful pregnancy were observed with embryo cryopreservation. Today, higher cure rates and longer survival are a result of earlier cancer diagnosis and treatment. In conjunction with the advances in assisted reproduction, the preservation of ovarian function and fertility is a major part of multidisciplinary care that should be offered to any young female patient with cancer. Fertility preservation in young cancer patients raises a number of ethical issues particularly regarding standard versus experimental therapies, and long-term financial cost.

Fertility-preserving treatment options in patients with malignant hematological diseases

The number of patients of reproductive age diagnosed with various malignant hematological diseases increases every year. These patients undergo chemotherapy, radiotherapy, and various other treatments that may have gonadotoxic effects. The life expectancy of these patients is increasing rapidly due to the variety of treatment options. As such, an increasing number of patients-as well as their parents and spouses-express their concerns about the patient's fertility post treatment. In the present review it was aimed to provide an overview of current fertility-preserving treatment options and the future of fertility preservation.

Results from the survey for preservation of adolescent reproduction (SPARE) study: gender disparity in delivery of fertility preservation message to adolescents with cancer

PURPOSE

Diminished reproductive capacity is a devastating consequence of life-sparing therapies for childhood malignancy. In 2006, the American Society of Clinical Oncology (ASCO) published fertility preservation recommendations (ASCOR) emphasizing the importance of early discussion and intervention for fertility preservation strategies. Using the Survey for Preservation of Adolescent REproduction (SPARE), we sought to determine fertility preservation attitudes and practice patterns post-ASCOR from pediatric oncology specialists nationwide.

MATERIALS AND METHODS

The SPARE survey consists of 22 questions assessing pediatric oncology specialists' attitudes and practice patterns toward fertility preservation. Broad perspectives on fertility preservation, including a willingness to discuss fertility, knowledge of current fertility preservation methods and awareness of ASCOR, were assessed.

RESULTS

The majority of respondents acknowledged that fertility threats are a major concern for them and agreed that all pubertal cancer patients should be offered a fertility consultation, but only 46% reported they refer male pubertal cancer patients to a fertility specialist prior to cancer treatment >50% of the time, and only 12% reported they refer female pubertal cancer patients to a fertility specialist prior to cancer treatment > 50% of the time. While 44% of respondents were familiar with the 2006 ASCOR, only 39% of those utilized them to guide decision-making in greater than half of their patients.

CONCLUSION

Our study demonstrates pediatric oncologists' motivation to preserve fertility in pediatric cancer patients; however, barriers to both gamete cryopreservation and referral to fertility specialists persist. Female pubertal patients are referred to fertility preservation specialists with much less frequency than are male pubertal patients, highlighting a disparity.

Ovarian transplantation for fertility preservation in a sheep model: can follicle loss be prevented by antiapoptotic sphingosine-1-phosphate administration?

AIMS

The aim of this study was to investigate whether sphingosine-1-phosphate (S1P), an apoptosis-inhibitor would be able to protect ovarian follicles from hypoxia-induced cell death in ovarian transplantation.

METHODS

In four sheep, both ovaries were removed and immediately transplanted back into the abdominal wall. In two of them, one ovary was treated with S1P locally by injection and incubation after dissecting the ovarian cortex. The contra lateral ovary of both sheep and both ovaries of the remaining sheep served as controls. After 2 weeks, all grafts were evaluated histologically.

RESULTS

Although the mean number of apoptotic cells were increased after grafting compared with fresh tissue, we were not able to demonstrate a significant difference regarding the follicular density in tissue with S1P treatment (mean number of follicles per field of view: 0.21 vs. 0.23, p = 0.909).

CONCLUSION

Apoptosis seems to play a role in follicular loss during ovarian transplantation; however, local application of S1P does not prevent primordial/primary follicles from hypoxia-induced cell death in cortical grafts in our study.

Four successful pregnancies in a patient with mucopolysaccharidosis type I treated by allogeneic bone marrow transplantation

To date, little is known about the fertility of women suffering from mucopolysaccharidosis type I (MPS I). We report on a female patient with MPS I treated by allogeneic bone marrow transplantation (BMT) at the age of 4 years (after a conditioning regimen containing busulfan 16 mg/kg and cyclophosphamide 100 mg/kg) who had four successful pregnancies without any reproductive assistance. Clinical and biological examinations of the children were normal. On the basis of this case, we discuss the fertility counselling of female MPS I patients at the time of BMT.

The Human Oocyte Preservation Experience (HOPE) a phase IV, prospective, multicenter, observational oocyte cryopreservation registry

BACKGROUND

It has been recommended by the American Society of Clinical Oncology and the American Society of Reproductive Medicine that options to preserve fertility be presented at the outset of treatment for cancer. This recommendation may have arisen, in part, to the increasing survival of patients with cancer and the realization that certain forms of cancer treatment can lead to infertility. One option for these patients, particularly those with ethical or religious objections to freezing embryos is oocyte cryopreservation. However universal acceptance of these procedures has yet to be established, most likely due to a poor history of success and concerns that there has yet to be a comprehensive approach to evaluating these techniques. In light of this, a registry of patients undergoing oocyte cryopreservation, called the HOPE registry, is being implemented.

DISCUSSION

The intent of the HOPE Registry is to enroll approximately 400 women of reproductive age who will undergo thawing/warming of oocytes and subsequent transfer. Data from the patients enrolled will be collected via a uniform, standardized form and will document important parameters such as demographics, laboratory procedures and outcomes, including following the outcomes of babies born for one year after birth. The results of the registry will be published on a yearly basis.

SUMMARY

A patient registry has been established in order to systematically document the techniques and outcomes of oocyte cryopreservation procedures. The results will be published in order to provide a widely accessible resource that will allow patients who are considering these procedures validated information in order to make informed decisions as to how their treatment will proceed.

Efficiency of human oocyte slow freezing: results from five assisted reproduction centres

It has been demonstrated previously that freezing oocytes within 2 h of retrieval increases the efficiency of cryopreservation via a slow-freezing/rapid-thawing protocol with 0.3 mol/l sucrose (SF/RT 0.3). The aim of this multicentre survey was to verify this observation on a larger scale. This was a retrospective study on the clinical outcome of 510 SF/RT 0.3 cycles divided into two groups: group A, freezing oocytes within 2 h of retrieval; group B, freezing oocytes more than 2 h after retrieval. The rate of best-quality embryos was significantly higher (33.24%) in group A than in group B (16.20%, P < 0.001). Pregnancy and implantation rates were 30.07% and 15.08% in group A versus 8.97% and 4.57% in group B (P < 0.001). Clinical pregnancy rates per thawed and per injected oocyte in group A were 5.53% and 10.41%, versus 1.46% and 2.77% in group B (P < 0.001). The overall yield from oocytes cryopreserved within 2 h of retrieval (group A) was 6.49 implantations per 100 oocytes thawed versus 1.74 for group B (P < 0.001). Embryo quality, pregnancy and implantation rates, and clinical efficiency of thawing cycles were all significantly improved when cryopreservation was carried out within 2 h of oocyte retrieval.

Breast cancer and fertility preservation

Many women affected with breast cancer are in their reproductive prime and at the time of their initial diagnosis have not yet started or completed their families. Improvements in outcomes for patients with breast cancer means longer survival times and oftentimes cures. Unfortunately, many of the treatments, while life-saving, are toxic to the finite supply of oocytes and diminish a woman's chance of future childbearing. After the initial shock of the cancer diagnosis has worn off, women are coming to the realization that their diagnosis is not a death sentence. Women that have not completed their families need to be informed about available options to protect their reproductive organs from the cancer treatments. The currently available options for fertility preservation should be discussed with every patient who is in their reproductive years prior to initiating any treatments. Fertility specialists should work closely with oncologists to counsel patients about the risks, if any, of the recommended treatment on their future fertility and discuss options to preserve potential fertility before starting treatments.

Autoimmune oophoritis in the adolescent

Autoimmune oophoritis presents in adolescents as a component of autoimmune polyendocrine syndrome type I or type II. Autoimmune oophoritis can be diagnosed in women with primary ovarian insufficiency in the presence of adrenal cortical or steroid cell antibodies, and/or antibodies to adrenal and ovarian steroidogenic enzymes. The ovaries are cystic macroscopically, with a lymphocytic infiltrate in the steroidogenic theca cells. The immune infiltrate results in low estradiol levels and a compensatory increase in FSH levels. Granulosa cells are spared, and inhibin A and B levels are normal to high. Treatment is aimed at symptom relief with further investigation needed to assess treatment options such as immunosuppression.

Abnormally low expression of connexin 37 and connexin 43 in subcutaneously transplanted cryopreserved mouse ovarian tissue

PURPOSE

To analyze the gap junction proteins connexin 37 (Cx37) and connexin 43 (Cx43) after subcutaneous transplantation of cryopreserved mouse ovarian tissue.

METHODS

Expression of gap junction genes was assessed by immunohistochemistry and real-time polymerase chain reaction (PCR) in transplanted cryopreserved ovarian tissue compared with that of normal ovarian tissue. Apoptosis of ovarian cells was evaluated by using the terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphates nick end-labeling method.

RESULTS

After subcutaneous transplantation, Cx37 and Cx43 mRNA and protein expression were significantly lower in cryopreserved than in normal ovarian tissue. Apoptosis was increased in granulosa cells from antral follicles of the cryopreserved tissue.

CONCLUSION

After cryopreservation and subcutaneous transplantation of ovarian tissue, proteins forming gap junctions between oocytes and granulosa cells are under-expressed compared with normal controls.

Female fertility and colorectal cancer

PURPOSE

It is estimated that the incidence of cancer in women aged 40 years or less is 8%. Females under the age of 40 are in their childbearing years. In the Western world, colorectal cancer (CRC) is the most common malignancy of the gastrointestinal tract. It is the third most commonly diagnosed cancer and the second leading cause of cancer-related death in the USA. The incidence of CRC in patients under 40 is 3-6%. Over the past decades, there has been a significant improvement in survival rates due to progress in cancer treatment, including CRC. This has been achieved with advances in adjuvant chemotherapeutic regimens. In the case of locally advanced rectal cancer, radiation therapy is also used. Treatment for CRC may have adverse effects on female fertility. The purpose of this paper is to discuss the effects of treatment of CRC on female fertility as well as the options for fertility preservation.

MATERIALS AND METHODS

A review of relevant English language articles was performed on the basis of a MEDLINE search of the keywords: female, fertility, fecundity, colon, rectal cancer, fertility preservation, chemotherapy, and radiation.

RESULTS

Surgical resection for colon cancer possibly has no effect on female fertility. Resection below the peritoneal reflection may adversely affect fertility, based on lower fertility and fecundity rates associated with pelvic surgery for ulcerative colitis and familial adenomatous polyposis. Standard 5-FU-based chemotherapy may not have significant effects. The advent of oxaliplatin in adjuvant chemotherapy may be more harmful. Adjuvant and neoadjuvant radiation therapy may cause premature ovarian failure using current dosing schedules. The effect of pregnancy and female hormones on the incidence, progression, and recurrence of CRC remains unclear. Established methods for fertility preservation include ovarian transposition and embryo cryopreservation. Oocyte cryopreservation has yielded inferior results. An investigational fertility preservation method is ovarian tissue cryopreservation, with promising results. Ovarian suppression and the use of apoptotic inhibitors are also investigational at present.

CONCLUSION

Young female patients need to be informed about the effects of treatment on fertility and options for fertility preservation. A multidisciplinary approach for appropriate consultation of these patients is mandatory.

Fertility preservation for women with malignancies: current developments of cryopreservation

The preservation of fertility in female cancer survivors has become an important health issue. The different cryopreservation options available for fertility preservation are embryo, oocyte, and ovarian tissue cryopreservation. Oocyte cryopreservation is available for women without partners, but there is a limited experience with this technique and the pregnancy rate is still low. In spite of recent reports of successful birth after autotransplantation of cryopreserved-thawed human ovarian cortical tissues, clinical experience is also limited and this technique remains still experimental. Whole ovary cryopreservation itself poses several challenges. Further researches for establishing optimal cryopreservation and thawing protocols and increasing post-thawing survival, pregnancy, and delivery rates are necessary. In this article, the strategies for fertility preservation in cancer survivors are discussed. The different options and their results are discussed, as well as their indications, efficacy and ethical issues.

Therapy Insight: preserving fertility in cyclophosphamide-treated patients with rheumatic disease

Cyclophosphamide remains a necessary treatment for severe rheumatic diseases, despite the continued search for alternative therapies with less gonadal toxicity. The risk of premature gonadal failure and sterility might lead young patients to delay treatment with cyclophosphamide. The patient's age at treatment and the cumulative dose received remain important risk factors for cyclophosphamide-induced gonadal failure in both males and females. Estrogen-containing oral contraceptives for females and testosterone for males are suggested to reduce the gonadal toxicity of cyclophosphamide, although few studies support these interventions. Owing to increased side effects, hormonal therapy is often avoided in patients with edema, hypertension, nephrotic syndrome or antiphospholipid antibodies. Agonists and antagonists of gonadotropin receptors are under study. Gonadotropin-receptor agonists might have beneficial effects in addition to suppression of sex-hormone production. The outcome of attempted cryopreservation of eggs, embryos or ovaries remains uncertain for women seeking to preserve their reproductive potential. Storing male gametes before chemotherapy is widely practiced and technically successful. As recovery of menses or production of testosterone does not predict individual fertility, identification of biomarkers of gonadal function and reserve, including serum levels of several hormones, ultrasonographic measurements of ovarian volume and antral follicle count, are necessary.

Premature ovarian failure and its consequences: vasomotor symptoms, sexuality, and fertility

Premature ovarian failure is a common consequence of systemic treatment for premenopausal breast cancer. Vasomotor symptoms and sexual dysfunction occur frequently in women who have an abrupt menopause from chemotherapy or ovarian suppression. However, current fertility may be impaired even in women who are menstruating after chemotherapy, and survivors are at high risk for permanent ovarian failure at a young age. Hot flashes can be managed with venlaxafine, gabapentin, or-potentially-stress management. Providing advice on treating vaginal dryness and brief sexual counseling can often alleviate sexual dysfunction. Options for fertility preservation remain limited but are improving rapidly. Distress about interrupted childbearing has a long-term impact on the quality of life.

Preservation of female fertility during cancer treatment

Improvements in the success of cancer treatments have resulted in increased awareness of the long-term effects of treatment, of which gonadal failure is the most significant. Thus, preservation of fertility potential has become a major goal and could be realized by preventing ovarian toxicity or by cryopreservation of reproductive cells/tissues. This review aimed to critically discuss the current protocols for the management of chemotherapy-inducced/radiotherapy-induced premature ovarian failure (POF). A medical approach using the gonadotropin-releasing hormone analog (GnRHa) may act to protect the gonads during radiation and/or chemotherapy by preferentially steering cells into cell cycle arrest with a decline in responsibility to the chemotherapeutic agents. Ovarian protection by GnRHa cotreatment against chemotherapy can enable the preservation of future fertility in survivors and prevent the bone demineralization and osteoporosis associated with hypestrogenism and POF. In vitro fertilization of retrieved oocytes could enable embryo freezing in some patients. Embryo cryopreservation is considered standard practice and widely available, but may seldom be used because of a lack of a male partner, the need to postpone cancer therapy for a few weeks and the possibility that an estrogen rise may be undesirable in sensitive cancer patients. Improvement in oocyte cryopreservation may offer additional possibilities; the prolonged culture of primordial and primary follicles in vitro is still unfeasible. Currently, the cryopreservation of ovarian cortex, which hosts thousands of immature follicles, is an investigational method, but has the advantage of requiring neither a sperm donor nor ovarian stimulation. Fertility preservation is often possible in women undergoing cancer treatment. To preserve the full range of options, fertility preservation procedures should be considered as early as possible during therapy planning. (Reprod Med Biol 2008; 7: 17-27).