Late reproductive sequelae following treatment of childhood cancer and options for fertility preservation

A dozen years of ovarian tissue cryopreservation at a pediatric hospital: tracking program and patient metrics while adapting to increasing needs

Objective

To review the program and patient metrics for ovarian tissue cryopreservation (OTC) within a comprehensive pediatric fertility preservation program in its first 12 years of development.

Design

Retrospective review.

Setting

A tertiary children's hospital in a large urban center between March 2011 and February 2023.

Patients

Pediatric patients who underwent OTC.

Interventions

Unilateral oophorectomy for OTC.

Main Outcome Measures

Patient demographics and clinical course information were collected for analysis.

Results

A total of 184 patients underwent OTC in the first 12 years. One hundred fifteen patients were prepubertal at the time of OTC, and 69 were postpubertal. In total, 128 patients (69.6%) received part of their planned therapy before OTC. Starting in 2018, 104 participants (92.0%) donated tissue to research, 99 participants (87.6%) donated blood, and 102 (90.2%) donated media to research. There was a decrease in the median age of patients who underwent OTC from 16.4-6.6 years and an overall increase in the proportion of patients per year that were prepubertal. Forty-eight (26.0%) patients who underwent OTC were outside referrals and traveled from as far as Seattle, Washington.

Conclusion

During the first 12 years of this program, oncofertility research increased, annual tissue cryopreservation cases increased, and the median age of those who underwent OTC decreased. The program was adapted to build a stand-alone gonadal tissue processing suite and specialized in prepubertal ovarian tissue processing. The program will continue to adapt to patient needs in the upcoming decades because restoration technologies advance through research supported by this and collaborating programs.

Cryostorage of human ovarian tissue: evaluating the storage and disposal pattern over a 22-year period in 2475 patients

RESEARCH QUESTION

What are the parameters of age, indications for ovarian tissue cryopreservation, storage characteristics and reasons for tissue disposal in a large cohort of individuals undertaking cryopreservation?

DESIGN

The relevant parameters in a single university centre were revised and digitalized in the period from 2019 to 2021. To assess patients' motivation at the end of storage, patients were contacted by letter, e-mails and telephone calls.

RESULTS

A group of 2475 patients with stored ovarian tissue were analysed in the time period between 2000 and 2021; the response rate for contact calls and letters was 28.8% (224/777). Where storage had ended (n = 1155), patients had on average stored for 3.8 years and begun storing at age 30 years; the main indications were breast cancer (53%) and lymphoma (17.5%). Of these participants, 2.5% had a transplantation on site, 10.3% transferred their tissue to another cryobank and 11.5% were deceased. The majority of the group (75.7%) ended their storage due to pregnancy (49.1%), a lack of desire to have children (25.9%), storage fees that were too expensive (8.9%), death (8.5%), recurrence of cancer (8.5%), lack of a partner (4%) and fear of surgery in the future (3.1%); 6.7% retrospectively regretted ending storage.

CONCLUSIONS

The pregnancy rate of 49.1%, resulting from ovarian tissue that was not removed during surgery for scheduled ovarian tissue cryopreservation supports the clinical approach of removing and cryopreserving only 25-50% of one ovary. It is proposed that interdisciplinary counselling should be implemented not only prior to fertility preservation, but also when intending to end storage.

Fertility status in childhood cancer survivors of hematological malignancies: a systematic review

Stunning advances in treatment modalities implemented in children with hematological malignancies have led to 5-year overall survival rates exceeding 85%. However, this growing population of long-term survivors has raised significant concerns about their fertility status throughout adulthood, while specific treatment- and non-treatment-related factors appear to possibly affect fertility through distinct mechanisms. We aimed to comprehensively review the published literature on the association between treatment-related factors and risk of impaired fertility in childhood hematological cancer survivors. We searched PubMed up to March 2021 to identify eligible studies published during the last two decades. A narrative synthesis of the results was performed, although no meta-analysis was feasible due to the small number of studies and the large heterogeneity of evidence. Five studies on 2020 survivors of childhood leukemia were deemed eligible. The qualitative data synthesis showed significant fertility deficits in survivors treated with cranial radiotherapy and chemotherapy for childhood leukemia. Two studies examined biochemical measures of reduced ovarian reserve, providing some evidence that the levels of anti-Müllerian hormone can be used as a proxy for diminished ovarian reserve. The current findings should facilitate the delivery of age- and gender-appropriate interventions to optimize reproductive outcomes in childhood hematological cancer survivors.

Ovarian Reserve Disorders, Can We Prevent Them? A Review

The ovarian reserve is finite and begins declining from its peak at mid-gestation until only residual follicles remain as women approach menopause. Reduced ovarian reserve, or its extreme form, premature ovarian insufficiency, stems from multiple factors, including developmental, genetic, environmental exposures, autoimmune disease, or medical/surgical treatment. In many cases, the cause remains unknown and resulting infertility is not ultimately addressed by assisted reproductive technologies. Deciphering the mechanisms that underlie disorders of ovarian reserve could improve the outcomes for patients struggling with infertility, but these disorders are diverse and can be categorized in multiple ways. In this review, we will explore the topic from a perspective that emphasizes the prevention or mitigation of ovarian damage. The most desirable mode of fertoprotection is primary prevention (intervening before ablative influence occurs), as identifying toxic influences and deciphering the mechanisms by which they exert their effect can reduce or eliminate exposure and damage. Secondary prevention in the form of screening is not recommended broadly. Nevertheless, in some instances where a known genetic background exists in discrete families, screening is advised. As part of prenatal care, screening panels include some genetic diseases that can lead to infertility or subfertility. In these patients, early diagnosis could enable fertility preservation or changes in family-building plans. Finally, Tertiary Prevention (managing disease post-diagnosis) is critical. Reduced ovarian reserve has a major influence on physiology beyond fertility, including delayed/absent puberty or premature menopause. In these instances, proper diagnosis and medical therapy can reduce adverse effects. Here, we elaborate on these modes of prevention as well as proposed mechanisms that underlie ovarian reserve disorders.

What should be done in terms of fertility preservation for patients with cancer? The French 2021 guidelines

AIM

To provide practice guidelines about fertility preservation (FP) in oncology.

METHODS

We selected 400 articles after a PubMed review of the literature (1987-2019).

RECOMMENDATIONS

Any child, adolescent and adult of reproductive age should be informed about the risk of treatment gonadotoxicity. In women, systematically proposed FP counselling between 15 and 38 years of age in case of treatment including bifunctional alkylating agents, above 6 g/m2 cyclophosphamide equivalent dose (CED), and for radiation doses on the ovaries ≥3 Gy. For postmenarchal patients, oocyte cryopreservation after ovarian stimulation is the first-line FP technique. Ovarian tissue cryopreservation should be discussed as a first-line approach in case of treatment with a high gonadotoxic risk, when chemotherapy has already started and in urgent cases. Ovarian transposition is to be discussed prior to pelvic radiotherapy involving a high risk of premature ovarian failure. For prepubertal girls, ovarian tissue cryopreservation should be proposed in the case of treatment with a high gonadotoxic risk. In pubertal males, sperm cryopreservation must be systematically offered to any male who is to undergo cancer treatment, regardless of toxicity. Testicular tissue cryopreservation must be proposed in males unable to cryopreserve sperm who are to undergo a treatment with intermediate or severe risk of gonadotoxicity. In prepubertal boys, testicular tissue preservation is: - recommended for chemotherapy with a CED ≥7500 mg/m2 or radiotherapy ≥3 Gy on both testicles. - proposed for chemotherapy with a CED ≥5.000 mg/m2 or radiotherapy ≥2 Gy. If several possible strategies, the ultimate choice is made by the patient.

Approaches and Technologies in Male Fertility Preservation

Male fertility preservation is required when treatment with an aggressive chemo-/-radiotherapy, which may lead to irreversible sterility. Due to new and efficient protocols of cancer treatments, surviving rates are more than 80%. Thus, these patients are looking forward to family life and fathering their own biological children after treatments. Whereas adult men can cryopreserve their sperm for future use in assistance reproductive technologies (ART), this is not an option in prepubertal boys who cannot produce sperm at this age. In this review, we summarize the different technologies for male fertility preservation with emphasize on prepubertal, which have already been examined and/or demonstrated in vivo and/or in vitro using animal models and, in some cases, using human tissues. We discuss the limitation of these technologies for use in human fertility preservation. This update review can assist physicians and patients who are scheduled for aggressive chemo-/radiotherapy, specifically prepubertal males and their parents who need to know about the risks of the treatment on their future fertility and the possible present option of fertility preservation.

Mice with a Sertoli cell-specific knockout of the Ctr1 gene exhibit a reduced sensitivity to cisplatin-induced testicular germ cell apoptosis

Exposure to the chemotherapeutic agent cis-diamminedichloroplatinum(ii) (cDDP) is well known to instigate acute and prolonged testicular injury in male patients.

Exposure to the chemotherapeutic agent cis-diamminedichloroplatinum(ii) (cDDP) is well known to instigate acute and prolonged testicular injury in male patients. Many investigators have hypothesized that cDDP-induced dysfunction of Sertoli cells (SCs) may, in part, account for the cDDP-induced lasting testicular injury. Nevertheless, the relative contribution of cDDP-induced SC injury versus direct effects on germ cells (GCs) to the pathogenesis of GC loss remains to be elucidated. The expression of the copper transporter 1 (CTR1) protein in cells directly corresponds with cDDP uptake and its cellular toxicity. Therefore, to discern the role of SCs in the pathogenic mechanism, mice were developed with a SC-specific disruption of the Ctr1 gene (SC^ΔCtr1) as a strategy to prevent their exposure to cDDP. Adult mice at postnatal day (PND) 60 were treated with 5 mg kg^–1 cDDP and then testis collected at 48 hours. A two-fold increase in GC-apoptosis occurred in the testis of cDDP-treated wildtype (WT) mice as compared to saline-treated WT mice. In contrast, cDDP-treated SC^ΔCtr1 mice exhibited only a half-fold increase in GC-apoptosis as compared to the saline-treated SC^ΔCtr1 mice. This reduced incidence of GC apoptosis in the SC^ΔCtr1 mice corresponded to a significantly lower level of platinum within the testis. Taken together, these findings reveal that the uptake of cDDP by CTR1 in SCs accounts for the accumulation of cDDP in the testis and plays a pivotal role in the pathogenic sequence of events leading to the loss of germ cells via apoptosis.

Female fertility preservation in DSD

Disorders of sex development (DSD) are a group of complex conditions that can affect chromosomal, gonadal, and/or phenotypical sex with a highly variable fertility potential amongst affected individuals. In this review we discuss fertility issues facing patients affected by DSD and Turner syndrome and summarise the literature on fertility and reproductive outcomes. We will also discuss fertility preservation prior to gonadotoxic treatment in adolescent and prepubertal girls. Future directions in fertility preservation and ethical issues will also be addressed. Fertility preserving options that are established include ovarian tissue and oocyte cryopreservation. However, in many of the DSDs fertility is not possible and the discussion may need to move toward alternative methods of creating a family such as gamete donation or surrogacy.

Hospitalization rate in offspring of cancer survivors: a national cohort study

Purpose

The number of childbirths among cancer survivors continues to increase, but it is still largely unknown whether the children of cancer survivors might experience adverse health outcomes during the process of growing up.

Methods

We identified all individuals diagnosed with cancer between 1958 and 2015 from the Swedish Cancer Registry and linked them to the Swedish Medical Birth Register to identify their offspring born between 1997 and 2015. Up to 10 children, whose parents did not have a diagnosis of cancer, were matched with the study population according to date of birth and gender.

Results

By linking with the Swedish Hospital Discharge Register, we found that the hospitalization rate was 15% higher in offspring of female cancer survivors, and 16% higher in offspring of male cancer survivors as compared to matched controls. Besides an increased risk of hospitalization due to malignant neoplasms (relative risk (RR) = 1.86, 99% CI 1.70–2.04) and benign neoplasms (RR = 1.48, 99% CI 1.18–1.86), a non-significant increased risk was found for hospitalization due to infectious and parasitic disease (RR = 1.09, 99% CI 0.98–1.21), diseases of the blood and blood-forming organs and certain disorders involving the immune mechanisms (RR = 1.33, 99% CI 0.98–1.80), and diseases of the circulatory system (RR = 1.05, 99% CI 0.98–1.12).

Conclusion

Our study suggests that children of cancer survivors might experience a significantly increased rate of hospitalization, which calls for further studies.

Implications for Cancer Survivors

Cancer survivors might be aware that the risk of hospitalization due to various diseases might be higher in their children as compared to the normal population.

Evaluation of an Educational Whiteboard Video to Introduce Fertility Preservation to Female Adolescents and Young Adults With Cancer

PURPOSE

Fertility is an important issue for adolescents and young adults with cancer facing potential infertility. Egg cryopreservation options exist, but information is sometimes overwhelming. We evaluated a fertility preservation educational video and assessed patient and family knowledge and impressions at pre- and post-video timepoints.

METHODS

We developed a whiteboard video to explain egg cryopreservation to patients and families. The video was evaluated on the basis of patient education best practices (readability, understandability, actionability). Participants were recruited using convenience sampling in oncology clinics. They completed questionnaires before and after watching to assess knowledge and interest. Inclusion criteria were patients age 13-39 years and minimum 1 month from diagnosis. Descriptive statistics, correlation analyses, and mean comparisons were conducted.

RESULTS

The video script read at a grade 8 reading level. Average understandability and actionability scores were below the acceptable standard. We recruited 108 patients (mean age, 27 years) and 39 caregivers/partners. Patients' knowledge about fertility preservation increased after viewing the video. Interest was high before and after, and satisfaction was high for both patients and caregivers. Participants appreciated information on process, procedure, and delivery but desired more information on logistics, including cost.

CONCLUSION

A targeted patient education video about fertility preservation options can build knowledge and encourage discussions about infertility. The video can be used as a model for videos on related topics to provide accurate information in a youth-friendly medium; however, following patient education best practices for readability, understandability, and actionability may increase video effectiveness. Future research should assess how audiovisual patient education material affects patient behavior.

Genotoxicity and pharmacokinetic characterization of Cereus jamacaru ethanolic extract in rats

The effect of Cereus jamacaru ethanolic extract in rats was analyzed using genotoxicity assays and liver ABCB1 and CYP2D4 gene expression. The lyophilized extract of C. jamacaru cladodes was analyzed with LC-MS/MS. Male Wistar rats (n=36) were equally distributed into six groups that did (+) or did not (-) receive cyclophosphamide treatments: Control (-); Control (+); EXP 1 (-), and EXP 1 (+), both treated with 210 mg/kg of ethanolic extract; and EXP 2 (-) and EXP 2 (+), both treated with 420 mg/kg of ethanolic extract. After 30 d of treatment, body weight and food and water intake were monitored. Right femur of the rats and spinal canal fluid were harvested and used for genotoxicity assays, and the liver samples were used for gene expression studies. The phytochemical analysis identified novel compounds. Animals treated with C. jamacaru showed lower body weight and food ingestion compared to controls (P<0.05). The genotoxicity assay showed an absence of ethanolic extract cytotoxicity. CYP2D4 expression was higher in EXP 2 groups compared with EXP 1 (-) group (P<0.05). ABCB1A expression was higher in negative groups compared with the positive groups. These results indicated a new phytochemical characterization of C. jamacaru and its effect on food ingestion and body weight gain. Moreover, the genotoxicity assay suggested that C. jamacaru ethanolic extract treatment presents significant intrinsic genotoxic potential and the enhanced expression of ABCB1 and CYP2D4 on C. jamacaru extract treatment suggests a role of the efflux transporter and microsomal enzyme, respectively, in C. jamacaru pharmacokinetics.

Reproductive Outcomes After a Childhood and Adolescent Young Adult Cancer Diagnosis in Female Cancer Survivors: A Systematic Review and Meta-analysis

Improvements in cancer therapy for childhood and adolescent and young adult (AYA) survivors have increased in excess of 80% among pediatric patients and in excess of 85% among AYA cancer patients. Our research group explored the late effects consequences of cancer treatment on pregnancy and birth outcomes subsequent to a childhood (0-14 years) or AYA (15-25 years) diagnosis of cancer in female cancer survivors. Embase and Medline databases were searched. There were 17 review (n = 10 matched and n = 7 unmatched) studies that met the inclusion criteria. Subanalyses were conducted on 10 matched studies. The median age for all studies for patients at diagnosis and birth was 11 and 27 years, respectively. In matched cohort studies, female childhood and AYA cancer patients, who received chemotherapy alone, had a pooled estimated rate of 18% of experiencing a live birth compared with 10% of females who received radiotherapy alone and subsequently had a live birth. Females who received surgery alone reported higher pooled estimated rates of 44% for a live birth. For matched retrospective review studies, 79% (n = 973) of women experienced a live birth, of which 22% of these babies were born preterm. This meta-analysis found lower birth rates for survivors. Access to fertility-related information and discussions around fertility preservation options and oncofertility psychosocial support should be offered to all cancer patients and their families before starting cancer treatment.

Liposomes: Clinical Applications and Potential for Image-Guided Drug Delivery

Liposomes have been extensively studied and are used in the treatment of several diseases. Liposomes improve the therapeutic efficacy by enhancing drug absorption while avoiding or minimizing rapid degradation and side effects, prolonging the biological half-life and reducing toxicity. The unique feature of liposomes is that they are biocompatible and biodegradable lipids, and are inert and non-immunogenic. Liposomes can compartmentalize and solubilize both hydrophilic and hydrophobic materials. All these properties of liposomes and their flexibility for surface modification to add targeting moieties make liposomes more attractive candidates for use as drug delivery vehicles. There are many novel liposomal formulations that are in various stages of development, to enhance therapeutic effectiveness of new and established drugs that are in preclinical and clinical trials. Recent developments in multimodality imaging to better diagnose disease and monitor treatments embarked on using liposomes as diagnostic tool. Conjugating liposomes with different labeling probes enables precise localization of these liposomal formulations using various modalities such as PET, SPECT, and MRI. In this review, we will briefly review the clinical applications of liposomal formulation and their potential imaging properties.

Fertility preservation training for obstetrics and gynecology fellows: a highly desired but non-standardized experience

BACKGROUND

Despite a large body of data suggesting that delivery of fertility care to cancer patients is inconsistent and frequently insufficient, there is a paucity of literature examining training in fertility preservation for those physicians expected to discuss options or execute therapy. The study objective was to compare fertility preservation training between Reproductive Endocrinology & Infertility (REI) and Gynecologic Oncology (GYN ONC) fellows and assess the need for additional education in this field.

METHODS

A 38-item survey was administered to REI and GYN ONC fellows in the United states in April 2014. Survey items included: 1) Clinical exposure, perceived quality of training, and self-reported knowledge in fertility preservation; 2) an educational needs assessment of desire for additional training in fertility preservation.

RESULTS

Seventy-nine responses were received from 137 REI and 160 GYN ONC fellows (response rate 27%). REI fellows reported seeing significantly more fertility preservation patients and rated their training more favorably than GYN ONC fellows (48% of REI fellows versus 7% of GYN ONC fellows rated training as 'excellent', p < 0.001). A majority of all fellows felt discussing fertility preservation was 'very important' but fellows differed in self-reported ability to counsel patients, with 43% of REI fellows and only 4% of GYN ONC fellows able to counsel patients 'all the time' (p = 0.002). Seventy-six percent of all fellows felt more education in fertility preservation was required, and 91% felt it should be a required component of fellowship training.

CONCLUSION

Significant variability exists in fertility preservation training for REI and GYN ONC fellows, with the greatest gap seen for GYN ONC fellows, both in perceived quality of fertility preservation training and number of fertility preservation patients seen. A majority of fellows in both disciplines support the idea of a standardized multi-disciplinary curriculum in fertility preservation.

Amelioration of the cyclophosphamide induced genotoxic damage in mice by the ethanolic extract of Equisetum arvense

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Plants like E. arvense posess not only nutritional value but therapeutic value as well.

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CPA is an important chemotherapeutic agent but is associated with various mutagenic and other toxic side effects.

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Ethanolic extract of the plant has immense protective effect against the genotoxic damage induced by the cyclophosphamide.

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GC–MS analysis of the extract shows various important phyto components which may be associated with its antimutagenic property.

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Plant can be used in cancer as a chemopreventive agent or even as a coadjuvant to chemotherapy to reduce the side effects associated with it.

In the present study, we evaluated the potential of the plant E. arvense against the cytotoxic and mutagenic effects induced by cyclophosphamide (chemotherapeutic agent) in the bone marrow cells of mice using the Chromosome assay (CA) and Mitotic index (MI) in vivo as the biomarkers. The study was performed following 3 protocols: pre-treatment, simultaneous treatment and post-treatment with the ethanolic extract of the plant. The results demonstrated that the plant extract was not cytotoxic and mutagenic and has a protective effect against the mutagenicity induced by cyclophosphamide in pre, simultaneous and post treatments and against its cytotoxicity as well. Because of its ability to prevent chromosomal damage, E. arvense is likely to open an interesting field concerning its possible use in clinical applications, most importantly in cancer as a chemopreventive agent or even as a coadjuvant to chemotherapy to reduce the side effects associated with it.

Effect of Premature Menopause on Sexuality

Premature menopause, that is, menopause – spontaneous or iatrogenic – occurring at or before the age of 40 years, affects sexual identity, sexual function and sexual relationships. The woman's health, wellbeing and achievement of life's goals may be variably impaired. Factors modulating the individual's sexual outcome after premature menopause include: etiological heterogeneity of premature menopause and associated medical and sexual comorbidities; psychosexual vulnerability to premature menopause and associated infertility in survivors of childhood and adolescent cancers; impact of premature menopause on women's sexual identity, sexual function – particularly the biological basis of desire, arousal, orgasm and vaginal receptivity – and sexual relationships; partner-related factors; fertility issues; and preventive/therapeutic measures. Hormone therapy is indicated but long-term safety data are lacking. An interdisciplinary medical and psychosexual approach comprises appropriate counseling, fertility protection, when feasible, individualized hormone therapy and specific psychosexual treatment(s). Further research on fertility protection and the safety of long-term hormone therapy after premature menopause is needed.

Vitrification of embryos and oocytes for fertility preservation in cancer patients

As survival rates and the life expectancy of those with malignancy have increased, more women in their reproductive years are referred for fertility preservation. Chemotherapy and radiotherapy can severely affect ovarian function, and the effect is irreversible. Therefore, it is optimal to attempt fertility preservation before chemotherapy and radiotherapy are initiated. Oocyte and embryo cryopreservation is the most common option for fertility preservation in women. Several reports have proven that embryo and oocyte cryopreservation can achieve a successful pregnancy. This review discusses the impact of chemotherapy and radiotherapy on ovarian function, and the importance of oocyte and embryo cryopreservation for fertility preservation. In addition, the current status of pregnancy outcomes and potential for cryopreserved oocytes to result in live births in cancer patients was reviewed. This may provide useful information for decision-making in cancer patients regarding oocyte and embryo cryopreservation and fertility preservation.

Late Effects of Treatment of Pediatric Central Nervous System Tumors

Central nervous system tumors represent the most common solid malignancy in childhood. Improvement in treatment approaches have led to a significant increase in survival rates, with over 70% of children now surviving beyond 5 years. As more and more children with CNS tumors have longer survival times, it is important to be aware of the long-term morbidities caused not only by the tumor itself but also by tumor treatment. The most common side effects including poor neurocognition, endocrine dysfunction, neurological and vascular late effects, as well as secondary malignancies, are discussed within this article.

Pubertal induction in hypogonadism: Current approaches including use of gonadotrophins

Primary disorders of the gonad or those secondary to abnormalities of the hypothalamic pituitary axis result in hypogonadism. The range of health problems of childhood and adolescence that affect this axis has increased, as most children now survive chronic illness, but many have persisting deficits in gonadal function as a result of their underlying condition or its treatment. An integrated approach to hormone replacement is needed to optimize adult hormonal and bone health, and to offer opportunities for fertility induction and preservation that were not considered possible in the past. Timing of presentation ranges from birth, with disorders of sexual development, through adolescent pubertal failure, to adult fertility problems. This review addresses diagnosis and management of hypogonadism and focuses on new management strategies to address current concerns with fertility preservation. These include Turner syndrome, and fertility presevation prior to childhood cancer treatment. New strategies for male hormone replacement therapy that may impinge upon future fertility are emphasized.

Strategies for fertility preservation in young patients with cancer: a comprehensive approach

As a result of treatment innovations, the survival rates of young people with cancer have increased substantially. The cancers most frequently diagnosed in adults aged 25-49 years include breast, colorectal and cervical cancer and malignant melanoma (Cancer Research UK, 2009). The 5-year survival rates of over 90 % for many malignancies are now reported in young people. But the diagnosis and treatment of cancer often poses a threat to fertility. Methods of fertility preservation are evolving quickly and awareness needs to grow in the medical community regarding these methods. Studies suggest that the ability to have biological children is of great importance to many people. The possible future effects of chemotherapy or radiotherapy on fertility should be discussed with all cancer patients who have reproductive potential. Moreover, fertility preservation should be considered for all young people undergoing potentially gonadotoxic treatment. This article covers the various methods of fertility preserving options in young men and women with respect to the various treatment modalities that they may be subjected to. Sperm banking is a simple and low cost intervention. Embryo cryopreservation is the only established method of female fertility preservation. Oocyte cryopreservation offers a useful option for women without a male partner. Emergency ovarian stimulation and cryopreservation of ovarian tissue (followed by tissue transplantation or in-vitro maturation of oocytes) are experimental techniques for women who require urgent cancer treatment. Large, well-controlled studies are also required to identify any unexpected long-term sequelae of cryopreservation of oocytes and ovarian tissue.

Which tools may help physicians in female fertility prediction after autologous bone marrow transplantation for lymphoma? A pilot study

OBJECTIVE(S)

The report of our experience on fertility preservation and the validation of some tools useful to predict fertility in young females who underwent haematopoietic cell transplantation for their lymphoma.

STUDY DESIGN

A retrospective study involving 17 consecutive women of child-bearing age affected by lymphoma and submitted to haematopoietic cell transplantation in our centre.

RESULTS

We described a high rate of parenthood in our patient series: 5 out of 17 (29%) patients became pregnant and 1 out of 5 had two pregnancies. It is suggestive that only patients who received gonadotropin-releasing hormone (GnRH) analogues co-treatment conceaved. Antral follicles number or ovarian volume, ascertained through transvaginal ultrasound before starting treatment, more than anti-Mullerian hormone (AMH) value, are tools that may help physicians to better predict fertility in young females of child-bearing age affected by lymphoma who desire to get pregnant after cancer cares.

CONCLUSION(S)

The high rate of maternity we recorded may lead to comfort the young women who hope to become pregnant after cancer cares because pregnancy is possible in a certain percentage of cases even after highly toxic treatments to the ovaries. A higher ovarian volume or a higher number of antral follicles, before treatment start, ensures a greater chance of successful pregnancies. AMH value in lymphoma survivors is not sufficient to guide physicians in fertility predictions.

Fertility preservation and reproduction in patients facing gonadotoxic therapies: a committee opinion

Chemotherapy and radiation therapy often result in reduced fertility, and patients receiving gonadotoxic treatment should be informed of options for fertility preservation and future reproduction prior to such treatment. Reproduction in the context of cancer also raises a number of ethical issues related to the welfare of both patients and offspring. This document replaces the document titled, "Fertility preservation and reproduction in cancer patients," last published in 2005 (Fertil Steril 2005;83:1622-8).

Hormone suppression with GnRH antagonist promotes spermatogenic recovery from transplanted spermatogonial stem cells in irradiated cynomolgus monkeys

Hormone suppression given before or after cytotoxic treatment stimulates the recovery of spermatogenesis from endogenous and transplanted spermatogonial stem cells (SSC) and restores fertility in rodents. To test whether the combination of hormone suppression and transplantation could enhance the recovery of spermatogenesis in primates, we irradiated (7 Gy) the testes of 12 adult cynomolgus monkeys and treated six of them with gonadotropin-releasing hormone antagonist (GnRH-ant) for 8 weeks. At the end of this treatment, we transfected cryopreserved testicular cells with green fluorescent protein-lentivirus and autologously transplanted them back into one of the testes. The only significant effect of GnRH-ant treatment on endogenous spermatogenesis was an increase in the percentage of tubules containing differentiated germ cells (tubule differentiation index; TDI) in the sham-transplanted testes of GnRH-ant-treated monkeys compared with radiation-only monkeys at 24 weeks after irradiation. Although transplantation alone after irradiation did not significantly increase the TDI, detection of lentiviral DNA in the spermatozoa of one radiation-only monkey indicated that some transplanted cells colonized the testis. However, the combination of transplantation and GnRH-ant clearly stimulated spermatogenic recovery as evidenced by several observations in the GnRH-ant-treated monkeys receiving transplantation: (i) significant increases (~20%) in the volume and weight of the testes compared with the contralateral sham-transplanted testes and/or to the transplanted testes of the radiation-only monkeys; (ii) increases in TDI compared to the transplanted testes of radiation-only monkeys at 24 weeks (9.6% vs. 2.9%; p = 0.05) and 44 weeks (16.5% vs. 6.1%, p = 0.055); (iii) detection of lentiviral sequences in the spermatozoa or testes of five of the GnRH-ant-treated monkeys and (iv) significantly higher sperm counts than in the radiation-only monkeys. Thus hormone suppression enhances spermatogenic recovery from transplanted SSC in primates and may be a useful tool in conjunction with spermatogonial transplantation to restore fertility in men after cancer treatment.

How do chemotherapeutic agents damage the ovary?

BACKGROUND

Chemotherapy treatment in premenopausal women is associated with an increased risk of premature ovarian failure (POF) but the exact mechanism through which this occurs is uncertain. In this review we examine the current evidence for the direct action of chemotherapeutic agents on the ovary and discuss possible molecular pathways through which follicle loss may occur.

METHODS

A systemic search of the databases, PubMed and Google Scholar, was made for all English language articles through to 2011 in each subject area discussed.

RESULTS

POF results from the loss of primordial follicles but this is not necessarily a direct effect of the chemotherapeutic agents. Instead, the disappearance of primordial follicles could be due to an increased rate of growth initiation to replace damaged developing follicles. Likewise, the loss of oocytes need not necessarily be a direct result of damage: evidence suggests that chemotherapy drugs can also induce oocyte death indirectly via damage to somatic cells. Specific molecular mechanisms and likely ovarian targets are discussed for some of the anti-cancer drugs most commonly used to treat premenopausal women. Finally, we consider current and prospective methods of preserving fertility.

CONCLUSIONS

It is likely that different chemotherapeutic drugs act through a range of mechanisms and on different target cells. More research into the cellular mechanisms underpinning chemotherapy-induced follicle loss could lead to the generation of treatments specifically designed to prevent POF.

Cryopreservation of human testicular diploid germ cell suspensions

For patients with threatened fertility, preservation of it is a major concern. Although promising results have been obtained in animal models using testicular germ cell suspensions, in humans, it is crucial to first develop an efficient method of cryopreservation to be able to apply to transplantation. Thus, four reliable and available cryopreservation techniques in any fertility centre were tested to cryopreserve an enriched fraction of diploid germ cells isolated from human testicular biopsies. The protocols were evaluated based on cell viability, and the results showed significant differences between the four methods. The semen and tissue cryopreservation methods appeared to be inadequate for diploid germ cell suspensions, and programmed slow freezing gave significantly lower results than open pulled straw vitrification; the latter was found to be the protocol that best preserved cell viability. The vitrification of isolated human diploid germ cells is innovative and constitutes valuable information for cryopreservation in cases of transplants or in vitro maturation.

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.

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.

Comparison of different adjuvant radiotherapy approaches in childhood bladder/prostate rhabdomyosarcoma treated with conservative surgery

BACKGROUND AND PURPOSE

Multimodality treatment approaches provide high local control and satisfying overall survival (OS) for children with localized bladder and/or prostate rhabdomyosarcoma (BP-RMS). However, current strategies including surgery and conventional radiotherapy are compromised by high rates of long-term genitourinary adverse effects. Therefore, a planning study combining organ preserving surgery with three different innovative adjuvant radiotherapy approaches was performed.

PATIENTS AND METHODS

A case of a 21-month-old boy with BP-RMS treated with polychemotherapy according to the CWS 2002-P protocol, prostatectomy, partial cystectomy, and adjuvant high dose rate brachytherapy (HDR-BT) was used to perform a planning study comparing HDR-BT with intensity-modulated radiotherapy (IMRT) and intensity-modulated proton therapy (IMPT) planning.

RESULTS

All modalities provide good coverage of the target volume and spare critical normal tissues. Rectum doses could be reduced by 2/3 using IMPT and by 1/3 using BT compared to IMRT. In terms of sparing the pelvis growth plates, BT and IMPT are also superior to IMRT.

CONCLUSION

All modalities provide good sparing of normal tissue. BT and IMPT are superior to IMRT with regard to doses on rectum and growth plates. BT is equivalent to IMPT in adequately selected tumors.

Reproductive outcomes for survivors of childhood cancer

Because of remarkable progress in therapy, long-term survival is expected for 80% of children and adolescents diagnosed with cancer. Infertility remains one of the most common and life-altering complications experienced by adults treated for cancer during childhood. Surgery, radiation, or chemotherapy that negatively affects any component of the hypothalamic-pituitary-gonadal axis may compromise reproductive outcomes in childhood cancer survivors. The risk of infertility is generally related to the tissues or organs involved in cancer and the specific type, dose, and combination of cytotoxic therapy. In addition to anticancer therapy, age at treatment, sex, and likely genetic factors influence the risk of permanent infertility. When possible, contemporary protocols limit cumulative doses of cytotoxic therapy in an effort to optimize reproductive potential. If sterilizing therapy is required for cancer control, then fertility preservation measures should be explored before initiation of therapy. For childhood cancer survivors who maintain fertility, health risks to offspring resulting from their cancer treatment are major concerns. Radiation affecting ovarian and uterine function has been linked to pregnancy complications, including spontaneous abortion, preterm labor, fetal malposition, and low birth weight. The risk of congenital malformations, genetic disorders, and cancer appears to be low, with the exception of cancer risk in offspring born to survivors with germline cancer-predisposing mutations. This review summarizes research about cancer treatment factors affecting fertility and pregnancy outcomes of childhood cancer survivors. The data presented should facilitate the delivery of preventive counseling and age- and sex-appropriate interventions to optimize reproductive outcomes in childhood cancer survivors.

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.

Anesthetic considerations for the pediatric oncology patient--part 3: pain, cognitive dysfunction, and preoperative evaluation

In part three of this three-part review, we continue with discussion of the effects of tumor and its therapy as they impact neurocognitive functioning, psychosocial issues of the patient and family, and the mechanisms and experience of pain in the child with cancer. A discussion of preanesthetic testing and evaluation in this patient population is next presented for the reader, focusing on the factors which pose the commonest and greatest risks to the child undergoing surgery. Lastly, an algorithmic approach to evaluating and managing key components of the medical history of pediatric patients is presented.

Paternal exposure to cyclophosphamide affects the progression of sperm chromatin decondensation and activates a DNA damage response in the prepronuclear rat zygote

Spermatozoon decondensation in the zygote leads to the initiation of chromatin remodeling during which protamines are removed and replaced with maternal histones. We hypothesize that damage to male germ cells induced by paternal exposure to cyclophosphamide may alter the timing of spermatozoal decondensation and the pattern of chromatin remodeling in the prepronuclear rat zygote. A specific order of sperm decondensation was observed, starting at the posterior end, proceeding to the ventral sides, followed by the tip, and finally the midbody region of the sperm head nucleus; subgroups of partially decondensed type a sperm nuclei were defined as types a1, a2, a3, and a4. Based on their frequencies relative to controls, paternal exposure to cyclophosphamide accelerated the timing of spermatozoal decondensation. Two distinct patterns of chromatin remodeling were observed for totally decondensed (type b) and recondensing (type c) sperm nuclei: H4K12ac showed a homogenous staining, whereas H3S10ph displayed a ring-like staining around the sperm nucleus; the distribution of these posttranslationally modified histones was not affected by cyclophosphamide exposure. In contrast, paternal cyclophosphamide treatment increased the number of gammaH2AX foci found in decondensing sperm nuclei. Small foci were significantly increased in type a2 and a3 nuclei, whereas a significant increase in the numbers of large foci was found in type b and c nuclei. This increase in gammaH2AX foci in the decondensing male genome suggests that damage recognition and repair pathways are initiated in prepronuclear rat zygotes. Thus, exposure of male rats to chronic low doses of cyclophosphamide accelerates spermatozoal decondensation and leads to the activation of gammaH2AX recognition of DNA damage in the male genome of the prepronuclear zygote.

Fertility preservation for cancer patients: a review

Infertility can arise as a consequence of treatment of oncological conditions. The parallel and continued improvement in both the management of oncology and fertility cases in recent times has brought to the fore-front the potential for fertility preservation in patients being treated for cancer. Oncologists must be aware of situations where their treatment will affect fertility in patients who are being treated for cancer and they must also be aware of the pathways available for procedures such as cryopreservation of gametes and/or embryos. Improved cancer care associated with increased cure rates and long term survival, coupled with advances in fertility treatment means that it is now imperative that fertility preservation is considered as part of the care offered to these patients. This can only be approached within a multidisciplinary setting. There are obvious challenges that still remain to be resolved, especially in the area of fertility preservation in prepubertal patients. These include ethical issues, such as valid consent and research in the area of tissue retrieval, cryopreservation, and transplantation.

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.

Male gonadal toxicity

Cancer treatment with chemotherapy or radiotherapy causes gonadal toxicity in male patients. The endpoint of most concern for future reproductive options is the induction of prolonged azoospermia, which may or may not be reversible. The immediate effects of therapy and its reversibility are most readily observed in post-pubertal patients, but the same antineoplastic regimens given to prepubertal males can induce permanent azoospermia. The probability of permanent azoospermia is related to the specific agents used and their doses. The most damaging are alkylating agents (particularly chlorambucil, procarbazine, cyclophosphamide, melphalan, and busulfan), cisplatin and radiation to the region of the testicles.

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.

Preventive role of exogenous testosterone on cisplatin-induced gonadal toxicity: an experimental placebo-controlled prospective trial

OBJECTIVE

To test the preventive role of exogenous T on spermatogenesis after cisplatin chemotherapy.

DESIGN

Placebo-controlled study.

SETTING

The animal laboratory of a medical university.

ANIMAL(S)

Eighty-eight male BALB/c mice were divided into three groups; each group was subdivided into four groups.

INTERVENTION(S)

Subgroups a received two or three cycles of cisplatin (2.5 mg/kg for 5 days + 16 days of recovery), subgroups b received the same chemotherapy regimen with adjuvant high-dose T enanthate (5 mg/100 g body weight) starting 1 week before chemotherapy and repeated every 21 days during chemotherapy, subgroups c received only high-dose T enanthate at the same dosage and intervals; subgroups d received a placebo.

MAIN OUTCOME MEASURE(S)

Testis spermatogenesis function was evaluated after 35 days (short term, group I) or 105 days (long term, groups II and III) of recovery, after the final dose of cisplatin, by histopathology and sperm count.

RESULT(S)

Testis tissue destruction and a significant dose-dependent decrease in spermatogenesis were identified in subgroups a. Both recovered partially during long-term recovery. Exogenous high-dose T caused damage to spermatogenesis, which was reversible (subgroups c). Adjuvant treatment with T had no additive long-term effect in animals treated with low-dose cisplatin (two cycles). However, a significant long-term preventive effect of T was seen in animals receiving high-dose cisplatin (three cycles).

CONCLUSION(S)

Hormonal intervention with exogenous T during chemotherapy had promising effects on spermatogenesis in mice receiving high-dose chemotherapy (regimens frequently used clinically). It had no additive long-term effects in animals receiving low-dose regimens.

Previous maternal chemotherapy by cyclophosphamide (Cp) causes numerical chromosome abnormalities in preimplantation mouse embryos

This study investigated the consequences of maternal cyclophosphamide treatment on fertilization rate, development and chromosomal integrity of embryos. It also evaluated efficiency of two methods of classic and metaphase induction for chromosomes assessment. Two different groups of NMRI mice 2-3 weeks and 6-7 weeks were injected intraperitonealy with 75 mg cyclophosphamide/kg. Six weeks later, oocytes were recovered, fertilized and incubated for 3 days in 5% CO(2) in air. Eight to 10 cell stage embryos were subjected to chromosomal study. Cyclophosphamide in both experimental groups reduced the oocyte fertilization rate and in the 6-7 weeks group it was significantly lower compared with control group (P<0.01). Also there was a reduction in 8-cell stage embryos formation from 48 to 72 h post-fertilization in both treated groups (P<0.05). Aneuploidy increased in the treatment groups compared with controls, which in the older group was significant (P<0.001). The success rate of the classic method to analyze metaphase plates was 30.1% and the success rate of heterokaryons formation with analyzable chromosomes was 67.8% in the metaphase induction method. In regards to the adverse effects of cyclophosphamide on fertilization rate, embryo development and chromosomal integrity of the mouse embryos, using Preimplantation Genetic Diagnosis in addition to Assisted Reproductive Technique is suggested.

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.

Subcutaneous autologous testicle transplantation in Wistar rats

OBJECTIVE

To assess the hormone secretion and viability of subcutaneous autotransplanted testicles in Wistar rats.

STUDY DESIGN

Wistar rats were randomly divided into four groups: sham (group I, n = 4), bilateral orchiectomy (group II, n = 4), sliced autotransplantation group (group III, n = 4), and whole-testicle autotransplantation group (group IV, n = 4). Sexual behavior (genital sniffing, thrusting intromissions, mounts with pelvic thrusting frequency), serum testosterone levels, and body weight were measured eight weeks after the procedure.

RESULTS

Subcutaneous autotransplantation elicited an increased number of mounts (P < 0.007) and intromissions (P < 0.009) and a significant reduction in the latency of these two behaviors (P < 0.034) compared with castrated animals. The frequency of sniffing of the bodies of sexually receptive females was not affected by castration (P = 0.326). Serum testosterone in whole autotransplantation group (219.23; 184.02-229.23) was higher than for the sliced autotransplantation group (0.74; 0.54-0.91) and bilateral orchiectomy group (0.59; 0.4-0.82; P < 0.05). We demonstrated that testicles transplanted without vascular anastomosis maintain their hormone secretion and exert neuroendocrine function on sexual behavior in rats. Autotransplantation could be an important alternative means of gonadal preservation for oncological patients considered for oncological therapies.

Long-term spermatogonial survival in cryopreserved and xenografted immature human testicular tissue

BACKGROUND

Preservation of the male germ line in prepubertal boys undergoing gonadotoxic treatment is a crucial consideration in terms of their future quality of life. As these patients do not yet produce spermatozoa for freezing, only immature tissue is available for storage. We studied the survival, proliferation and differentiation capacity of spermatogonia after cryopreservation and long-term transplantation of immature testicular tissue pieces.

METHODS

Single pieces of testicular tissue (2-8 mm(3)) from prepubertal boys (7-14 years) were cryopreserved, thawed and transplanted into the scrotum of mice for 6 months. Upon removal, histological, immunohistochemical and ultrastructural analyses and testicular sperm extraction (TESE) were used to evaluate the tissue.

RESULTS

Histology showed 55 +/- 42% of tubules to be intact. MAGE-A4 immunostaining showed mean spermatogonial recovery to be 3.7 +/- 5.5%, with 35% of these cells expressing Ki67, evidencing proliferation in tissue from boys <14 years of age. No apoptosis was found, as demonstrated by the absence of active caspase-3 and TUNEL staining. Numerous premeiotic spermatocytes, a few spermatocytes at the pachytene stage and spermatid-like cells were observed. No immunostaining was observed for lactate dehydrogenase-C, ACE or proacrosin, indicating that the spermatid-like structures observed by histology did not express the meiotic and post-meiotic markers characteristic of normal spermatids. No ultrastructural alterations of the tissue were encountered.

CONCLUSIONS

The present study demonstrates that spermatogonia are able to survive and proliferate after cryopreservation and long-term transplantation. Complete regeneration of normal spermatogenesis was not observed since, beyond the pachytene stage, no adequate characterization of germ cells was obtained. Further studies are thus required to investigate the differentiation potential of cryopreserved germ cells.