Fertility preservation in boys facing gonadotoxic cancer therapy

Male fertility restoration: in vivo and in vitro stem cell-based strategies using cryopreserved testis tissue: a scoping review

IMPORTANCE

Advances in the treatment of childhood cancer have significantly improved survival rates, with more than 80% of survivors reaching adulthood. However, gonadotoxic cancer treatments endanger future fertility, and prepubertal males have no option to preserve fertility by sperm cryopreservation. In addition, boys with cryptorchidism are at risk of compromised fertility in adulthood.

OBJECTIVE

To investigate current evidence for male fertility restoration strategies, explore barriers to clinical implementation, and outline potential steps to overcome these barriers, a scoping review was conducted. This knowledge synthesis is particularly relevant for prepubertal male cancer survivors and boys with cryptorchidism.

EVIDENCE REVIEW

The review was conducted after the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews criteria and previously published guidelines and examined studies using human testis tissue of prepubertal boys or healthy male adults. A literature search in PubMed was conducted, and 72 relevant studies were identified, including in vivo and in vitro approaches.

FINDINGS

In vivo strategies, such as testis tissue engraftment and spermatogonial stem cell transplantation, hold promise for promoting cell survival and differentiation. Yet, complete spermatogenesis has not been achieved. In vitro approaches focus on the generation of male germ cells from direct germ cell maturation in various culture systems, alongside human induced pluripotent stem cells and embryonic stem cells. These approaches mark significant advancements in understanding and promoting spermatogenesis, but achieving fully functional spermatozoa in vitro remains a challenge. Barriers to clinical implementation include the risk of reintroducing malignant cells and introduction of epigenetic changes.

CONCLUSION

Male fertility restoration is an area in rapid development. On the basis of the reviewed studies, the most promising and advanced strategy for restoring male fertility using cryopreserved testis tissue is direct testis tissue transplantation.

RELEVANCE

This review identifies persistent barriers to the clinical implementation of male fertility restoration. However, direct transplantation of frozen-thawed testis tissue remains a promising strategy that is on the verge of clinical application.

Fertility preservation in males with cancer of trends, region development, and efficacy in mainland China from 16 regions Chinese sperm banks

PURPOSE

Male cancer survivors experience confusion about fertility following cancer treatment. The aims of this study were to evaluate survivors' semen quality in different tumor type groups in China and to analyze the current situation and challenges of male cancer patients with sperm cryopreservation.

METHODS

This was a multicenter retrospective study of male patients with cancer who underwent sperm cryopreservation in 16 regions of the national sperm banks over an 11-year period from 2010 to 2020.

RESULTS

The number of male cancer patients with sperm cryopreservation showed an overall upward trend. The development of male cancer fertility preservation (FP) in the eastern, central, and western regions of Chinese displayed imbalance. There are seven tumor types for sperm preservation in the top incidence ten tumor types, including lymphoma, leukemia, nasopharyngeal carcinoma, sarcoma, thyroid cancer, and brain tumor. Moreover, nasopharyngeal carcinoma is a high incidence rate in China, which is related to high sperm preservation rate, different from other countries. The most percentage of males receiving sperm cryopreservation in the testicular cancers (15-39 years old) of China in 2020 was 5.55%, 1.29% in the lymphoma, and 0.39% in the leukemia. According to the type of cancer, a statistically significant lower pre-sperm density, total sperm output, and post-sperm density was observed in testicular cancers. It is worth noting that the prevalence of azoospermia 22.2% in leukemia patients attribute to urgent treatment before sperm cryopreservation. Disposition of cryopreserved sperm categories included continued storage (47.2%), discarded (9%), death (0.9%), and use (3.7%).

CONCLUSION

This study provides the first comprehensive national statistical census and review of fertility preservation in male cancer patients with respect to trends, prevalence, and cancer types. The development of male cancer fertility preservation in China is imbalanced and percentage of males receiving sperm cryopreservation in the adolescent and young adult cancers was low. Sixteen human sperm banks from China analyze current problems and challenges, and then prioritize steps toward the achievement of the FP strategy framework for Healthy China 2030.

Male Infertility: New Developments, Current Challenges, and Future Directions

There have been many significant scientific advances in the diagnostics and treatment modalities in the field of male infertility in recent decades. Examples of these include assisted reproductive technologies, sperm selection techniques for intracytoplasmic sperm injection, surgical procedures for sperm retrieval, and novel tests of sperm function. However, there is certainly a need for new developments in this field. In this review, we discuss advances in the management of male infertility, such as seminal oxidative stress testing, sperm DNA fragmentation testing, genetic and epigenetic tests, genetic manipulations, artificial intelligence, personalized medicine, and telemedicine. The role of the reproductive urologist will continue to expand in future years to address different topzics related to diverse questions and controversies of pathophysiology, diagnosis, and therapy of male infertility, training researchers and physicians in medical and scientific research in reproductive urology/andrology, and further development of andrology as an independent specialty.

The male reproductive toxicity after 5-Fluorouracil exposure: DNA damage, oxidative stress, and mitochondrial dysfunction in vitro and in vivo

5-Fluorouracil (5-FU), a chemotherapeutic drug used to treat a variety of cancers, can enter the environment through different routes, causing serious public health and environmental concerns. It has been reported that 5-FU exposure adversely affects male reproductive function, and its effects on this system cannot be avoided. In this study, using western blotting and quantitative polymerase chain reaction studies, we found that 5-FU promoted testicular injury by inducing oxidative stress, which was accompanied by the inhibition of nuclear factor erythroid 2-related factor 2/antioxidant response element signaling. Accumulation of reactive oxygen species (ROS) aggravated 5-FU-mediated mitochondrial dysfunction and apoptosis in murine cell lines and testes, indicating oxidative stress and mitochondrial-dependent apoptotic signaling play crucial roles in the damage of spermatogenic cells caused. N-Acetyl-L-cysteine, an antioxidant that scavenges intracellular ROS, protected spermatogenic cells from 5-FU-induced oxidative damage and mitochondrial dysfunction, revealing the important role of ROS in testicular dysfunction caused by 5-FU. We found that 5-FU exposure induces testicular cell apoptosis through ROS-mediated mitochondria pathway in mice. In summary, our findings revealed the reproductive toxicological effect of 5-FU on mice and its mechanism, provided basic data reference for adverse ecological and human health outcomes associated with 5-FU contamination or poisoning.

Fertility preservation in male adolescents with cancer (2011-2020): A retrospective study in China

BACKGROUND

According to the studies, more than 80% of pediatric patients with cancer can achieve a survival rate greater than 5 years; however, long-term chemotherapy and/or radiation therapy may seriously affect their reproductive ability. Fertility preservation in adolescents with cancer in China was initiated late, and related research is lacking. Analyze data to understand the current situation and implement measures to improve current practices.

METHODS

From 2011 to 2020, data on 275 male adolescents with cancer whose age ranged from 0 to 19 years old were collected from 16 human sperm banks for this retrospective study. Methods include comparing the basic situation of male adolescents with cancer, the distribution of cancer types, and semen quality to analyze the status of fertility preservation.

RESULTS

The mean age was 17.39 ± 1.46 years, with 13 cases (4.7%) aged 13-14 years and 262 cases (95.3%) aged 15-19 years. Basic diagnoses included leukemia (55 patients), lymphomas (76), germ cell and gonadal tumors (65), epithelial tumors (37), soft tissue sarcomas (14), osteosarcoma (7), brain tumors (5), and other cancers (16). There are differences in tumor types in different age stages and regions. The tumor type often affects semen quality, while age affects semen volume. Significant differences were found in sperm concentration and progressive motility before and after treatment (p < 0.001). Moreover, 90.5% of patients had sperm in their semen and sperm were frozen successfully in 244 patients (88.7%).

CONCLUSIONS

The aim of this study is to raise awareness of fertility preservation in male adolescents with cancer, to advocate for fertility preservation prior to gonadotoxic therapy or other procedures that may impair future fertility, and to improve the fertility status of future patients.

Current Status of Fertility Preservation in Pediatric Oncology Patients

Cancer poses significant emotional challenges for children and adolescents, despite improvements in survival rates due to new therapies. However, there is growing concern about the long-term effects, including fertility issues. This review examines recent advancements and future directions in fertility preservation within a pediatric population subjected to oncological therapies. Worldwide, there is variability in the availability of fertility preservation methods, influenced by factors like development status and governmental support. The decision to pursue preservation depends on the risk of gonadotoxicity, alongside factors such as diagnosis, treatment, clinical status, and prognosis. Currently, options for preserving fertility in prepubertal boys are limited compared to girls, who increasingly have access to ovarian tissue preservation. Adolescents and adults have more options available, but ethical considerations remain complex and diverse.

Application of photocrosslinked gelatin, alginate and dextran hydrogels in the in vitro culture of testicular tissue

Testicular tissue culture in vitro is considered an important tool for the study of spermatogenesis and the treatment of male infertility. Although agarose hydrogel is commonly used in testicular tissue culture, the efficiency of spermatogenesis in vitro is limited. In this study, testicular tissues from adult mice were cultured using a gas-liquid interphase method based on agarose (Agarose), gelatin methacryloyl (GelMA), alginate methacryloyl (AlgMA), dextran methacryloyl (DexMA), and mixture GelMA-Agarose, AlgMA-Agarose, and DexMA-Agarose hydrogels, respectively, for 32 days in vitro. The integrity of the seminiferous tubules, the density and proportions of spermatogonia, spermatocytes, Sertoli cells, and testosterone concentrations were quantified and compared between groups. Properties of different hydrogels including compression modulus, Fourier Infrared Spectroscopy (FITR) spectra, pore size, water absorption, and water retention were tested to investigate how biochemical and physical properties of hydrogels affect the results of testicular tissue culture. The results indicate that testicular tissues cultured on AlgMA exhibited the highest seminiferous tubule integrity rate (0.835 ± 0.021), the presence of a high density of spermatocytes (2107.627 ± 232.082/mm2), and a high proportion of SOX9-positive well-preserved seminiferous tubules (0.473 ± 0.047) compared to all remaining experimental groups on day 32. This may be due to the high water content of AlgMA reducing the toxic effect of oxygen on testicular tissue. In the later period of culture, testicular tissues cultured on DexMA, not DexMA-Agarose, produced significantly more testosterone (18.093 ± 3.302 ng/mL) than the other groups, suggesting that DexMA is friendly to Leydig cells. Our study provides a new idea for the optimization of the gas-liquid interphase method for achieving in vitro spermatogenesis, facilitating the future achievement of efficient in vitro spermatogenesis in more species, including humans.

Results from the first autologous grafting of adult human testis tissue: a case report

Fertility restoration using autologous testicular tissue transplantation is relevant for infertile men surviving from childhood cancer and, possibly, in men with absent or incomplete spermatogenesis resulting in the lack of spermatozoa in the ejaculate (non-obstructive azoospermia, NOA). Currently, testicular tissue from pre-pubertal boys extracted before treatment with gonadotoxic cancer therapy can be cryopreserved with good survival of spermatogonial stem cells. However, strategies for fertility restoration, after successful cancer treatment, are still experimental and no clinical methods have yet been developed. Similarly, no clinically available treatments can help men with NOA to become biological fathers after failed attempts of testicular surgical sperm retrieval. We present a case of a 31-year-old man with NOA who had three pieces of testis tissue (each ∼2 × 4 × 2 mm3) extracted and cryopreserved in relation to performing microdissection testicular sperm extraction (mTESE). Approximately 2 years after mTESE, the thawed tissue pieces were engrafted in surgically created pockets bilaterally under the scrotal skin. Follow-up was performed after 2, 4, and 6 months with assessment of reproductive hormones and ultrasound of the scrotum. After 6 months, all engrafted tissue was extracted and microscopically analyzed for the presence of spermatozoa. Furthermore, parts of the extracted tissue were analyzed histologically and by immunohistochemical analysis. Active blood flow in the engrafted tissue was demonstrated by doppler ultrasound after 6 months. No spermatozoa were found in the extracted tissue. Histological and immunohistochemical analysis demonstrated graft survival with intact clear tubules and normal cell organization. Sertoli cells and spermatocytes with normal morphology were located near the basement membrane. MAGE-A and VASA positive spermatogonia/spermatocytes were detected together with SOX9 positive Sertoli cells. Spermatocytes and/or Sertoli cells positive for γH2AX was also detected. In summary, following autologous grafting of frozen-thawed testis tissue under the scrotal skin in a man with NOA, we demonstrated graft survival after 6 months. No mature spermatozoa were detected; however, this is likely due to the pre-existing spermatogenic failure.

Clinical Care for People Who Survive Childhood Cancer: A Review

Importance

An estimated 15 000 children and adolescents aged 0 to 19 years are diagnosed with cancer each year in the US, and more than 85% survive for at least 5 years. By 45 years of age, approximately 95% of people who survive childhood cancer will develop a significant health problem related to the childhood cancer diagnosis or its treatment.

Observations

Approximately 500 000 people currently alive in the US have survived childhood cancer. The most common severe or life-threatening chronic health problems related to childhood cancer or its treatment are endocrine disorders such as hypothyroidism or growth hormone deficiency (44%), subsequent neoplasms such as breast cancer or thyroid cancer (7%), and cardiovascular disease such as cardiomyopathy or congestive heart failure, coronary artery disease, and cerebrovascular disease (5.3%). Medical conditions related to a cancer diagnosis during childhood or adolescence are most commonly caused by the radiation therapy and the chemotherapies used to treat cancer and may develop at varying lengths of time after exposure to these treatments. Individuals at highest risk for developing treatment-related health problems include patients with brain cancer treated with cranial irradiation (approximately 70% develop severe or life-threatening health problems) and allogeneic hematopoietic stem cell transplant recipients (approximately 60% develop severe or life-threatening health problems). Individuals at the lowest risk for developing treatment-related health problems include those who survived solid tumors (such as Wilms tumor) treated with surgical resection alone or with minimal chemotherapy, for whom the prevalence of subsequent health problems is similar to people who did not have cancer during childhood or adolescence. People diagnosed with childhood cancer in the 1990s who survived for at least 5 years after the cancer diagnosis have a shorter lifespan (by about 9 years) vs children who were not diagnosed with cancer in the 1990s.

Conclusions and Relevance

Approximately 500 000 individuals currently alive in the US have survived childhood cancer. The most common adverse effects in individuals who survived childhood cancer are endocrine disorders, subsequent neoplasms, and cardiovascular disease. There is a need for clinicians and patients to have heightened awareness of these complications.

Cryostorage management of reproductive cells and tissues in ART: status, needs, opportunities and potential new challenges

Among the wide range of procedures performed by clinical embryologists, the cryopreservation of reproductive cells and tissues represents a fundamental task in the daily routine. Indeed, cryopreservation procedures can be considered a subspecialty of medically assisted reproductive technology (ART), having the same relevance as sperm injection or embryo biopsy for preimplantation genetic testing. However, although a great deal of care has been devoted to optimizing cryopreservation protocols, the same energy has only recently been spent on developing and implementing strategies for the safe and reliable storage and transport of reproductive specimens. Herein, we have summarized the content of the available guidelines, the risks, the needs and the future perspectives regarding the management of cryopreservation biorepositories used in ART.

Onco-TESE (Testicular Sperm Extraction): Insights from a Tertiary Center and Comprehensive Literature Analysis

Background and Objectives: The peak of incidence of testicular cancer (TC) occurs among individuals in their reproductive age, emphasizing the importance of fertility preservation as an integral aspect of disease management. Sperm cryopreservation performed before orchiectomy is ineffective in azoospermic men, necessitating alternative approaches such as microdissection testicular sperm extraction (mTESE) at the time of orchiectomy (onco-mTESE) to obtain viable sperm. This study presents the findings from our institution's experience with onco-mTESE and critically discusses our results in light of the existing body of literature. Materials and Methods: This is a tertiary center retrospective analysis of onco-mTESE procedures performed at a single center between December 2011 and July 2022. The included patients were post-puberal men with testicular tumors requiring orchiectomy, along with concomitant severe oligozoospermia or azoospermia. Bilateral mTESE was performed in all cases. Surgical outcomes, sperm retrieval rates, the usage of preserved viable sperm, assistive reproductive techniques' results, and post-operative serum testosterone were recorded. Results: A total of nine patients were included, with a median age of 34 (IQR 29-36) years. All patients had germ cell tumors (GCTs), with seminomatous and non-seminomatous GCTs accounting for 44.4% (n = 4) and 55.6% (n = 5) of patients, respectively. Sperm retrieval occurred in three (33%) patients: one patient in the ipsilateral testis, one in the contralateral testis, and one in both testes. No complications were reported during the procedure, and no post-operative hypogonadism was observed. Among the three patients with successful sperm retrieval, an intracytoplasmic sperm injection (ICSI) was performed in two patients, resulting in two pregnancies, leading to one healthy live birth and one miscarriage. Conclusions: In the context of TC, it is essential to conduct a thorough evaluation of testicular function, including a semen analysis and cryopreservation. Onco-mTESE has proven its safety in preserving fertility in azoospermic cases while ensuring the efficacy of oncological treatment.

Fertility preservation in pediatric healthcare: a review

Survival rates for children and adolescents diagnosed with malignancy have been steadily increasing due to advances in oncology treatments. These treatments can have a toxic effect on the gonads. Currently, oocyte and sperm cryopreservation are recognized as well-established and successful strategies for fertility preservation for pubertal patients, while the use of gonadotropin-releasing hormone agonists for ovarian protection is controversial. For prepubertal girls, ovarian tissue cryopreservation is the sole option. However, the endocrinological and reproductive outcomes after ovarian tissue transplantation are highly heterogeneous. On the other hand, immature testicular tissue cryopreservation remains the only alternative for prepubertal boys, yet it is still experimental. Although there are several published guidelines for navigating fertility preservation for pediatric and adolescent patients as well as transgender populations, it is still restricted in clinical practice. This review aims to discuss the indications and clinical outcomes of fertility preservation. We also discuss the probably effective and efficient workflow to facilitate fertility preservation.

Effect of Distance From Fertility Center on Utilization of Fertility Preservation Referral in Men

PURPOSE

Fertility preservation (FP) is underutilized in males with cancer or other diseases requiring gonadotoxic therapies. We sought to evaluate whether patient distance from FP center affected rates of providing a semen analysis after referral.

MATERIALS AND METHODS

We performed a retrospective analysis of all males who were referred for FP at a single institution between 2013 and 2021. A multiple logistic regression model was conducted with semen sample submission as the variable of interest. Predictor variables were disease type, distance, and payment method. Secondary outcomes were number of semen samples submitted and number of vials collected.

RESULTS

Records of 461 males referred to our center were analyzed. Of these patients, 326 (71%) provided a semen sample after referral and 135 (30%) did not. Further distance from our center was associated with lower odds of submitting a semen sample (OR, 0.85; 95% CI, 0.75 to 0.97; P < .05). For patients who submitted at least one sample, distance did not affect the total number of samples submitted but was associated with a small increase in total vials cryopreserved.

CONCLUSION

Men referred for FP exhibit a high rate of sperm cryopreservation. Further distance from FP center was associated with decreased odds to provide semen sample after referral. Our model estimated a 15% decrease in odds of collection with every doubling of distance from our center. Efforts must be made to improve FP utilization for patients traveling far distances, but distance alone should not preclude referral.

Germ Cell Maintenance and Sustained Testosterone and Precursor Hormone Production in Human Prepubertal Testis Organ Culture with Tissues from Boys 7 Years+ under Conditions from Adult Testicular Tissue

Human prepubertal testicular tissues are rare, but organ culture conditions to develop a system for human in vitro-spermatogenesis are an essential option for fertility preservation in prepubertal boys subjected to gonadotoxic therapy. To avoid animal testing in line with the 3Rs principle, organ culture conditions initially tested on human adult testis tissue were applied to prepubertal samples (n = 3; patient ages 7, 9, and 12 years). Tissues were investigated by immunostaining and transmission electron microscopy (TEM), and the collected culture medium was profiled for steroid hormones by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Culture conditions proved suitable for prepubertal organ culture since SSCs and germ cell proliferation could be maintained until the end of the 3-week-culture. Leydig cells (LCs) were shown to be competent for steroid hormone production. Three additional testis tissues from boys of the same age were examined for the number of germ cells and undifferentiated spermatogonia (SPG). Using TEM micrographs, eight tissues from patients aged 1.5 to 13 years were examined, with respect to the sizes of mitochondria (MT) in undifferentiated SPG and compared with those from two adult testicular tissues. Mitochondrial sizes were shown to be comparable between adults and prepubertal boys from approximately 7 years of age, which suggests the transition of SSCs from normoxic to hypoxic metabolism at about or before this time period.

Germline stem cells in human

The germline cells are essential for the propagation of human beings, thus essential for the survival of mankind. The germline stem cells, as a unique cell type, generate various states of germ stem cells and then differentiate into specialized cells, spermatozoa and ova, for producing offspring, while self-renew to generate more stem cells. Abnormal development of germline stem cells often causes severe diseases in humans, including infertility and cancer. Primordial germ cells (PGCs) first emerge during early embryonic development, migrate into the gentile ridge, and then join in the formation of gonads. In males, they differentiate into spermatogonial stem cells, which give rise to spermatozoa via meiosis from the onset of puberty, while in females, the female germline stem cells (FGSCs) retain stemness in the ovary and initiate meiosis to generate oocytes. Primordial germ cell-like cells (PGCLCs) can be induced in vitro from embryonic stem cells or induced pluripotent stem cells. In this review, we focus on current advances in these embryonic and adult germline stem cells, and the induced PGCLCs in humans, provide an overview of molecular mechanisms underlying the development and differentiation of the germline stem cells and outline their physiological functions, pathological implications, and clinical applications.