Fertility preservation in men: a contemporary overview and a look toward emerging technologies

Testicular Cancer Survivorship and Fertility Preservation

Testicular cancer disproportionally affects men of reproductive age making fertility an important aspect of testicular cancer survivorship. Men with testicular cancer have more semen parameter abnormalities and a higher incidence of infertility compared to the general population. All treatment options for testicular cancer negatively affect fertility with recovery rates varying by treatment. For these reasons, clinicians should offer sperm cryopreservation, ideally before orchiectomy to maximize the possibility of biologic paternity, if desired. Several innovations have positively impacted this space including direct-to-consumer cryopreservation and bench research demonstrating the feasibility of reintroducing testicular cells post-therapy.

Tackling Non-Small Cell Lung Cancer in Young Adults: From Risk Factors and Genetic Susceptibility to Lung Cancer Profile and Outcomes

Lung cancer has traditionally been associated with advanced age; however, its increasing incidence among young adults raises concerning questions regarding its etiology and unique considerations for this population. In contrast to the older population, the onset of lung cancer at younger age may be attributed to a complex interplay of incompletely understood individual susceptibility and prevalent environmental risk factors beyond tobacco smoke exposure, such as radon gas and air pollution, which are widespread globally. Consequently, this leads to distinct clinical and molecular profiles, requiring a tailored approach. Furthermore, a diagnosis of cancer represents a threatening event during the prime years of a young person's life, prompting concern about career development, social aspects, fertility aspirations, and physical independence. This poses significant additional challenges for health care professionals in a field that remains underexplored. This comprehensive review recognizes lung cancer in young adults as a distinct entity, exploring its clinical and molecular characteristics, diverse predisposing factors, and priorities in terms of quality of life, with the aim of providing practical support to oncologists and enhancing our understanding of this under-researched population.

Trace and essential elements as vital components to improve the performance of the male reproductive system: Implications in cell signaling pathways

Successful male fertilization requires the main processes such as normal spermatogenesis, sperm capacitation, hyperactivation, and acrosome reaction. The progress of these processes depends on some endogenous and exogenous factors. So, the optimal level of ions and essential and rare elements such as selenium, zinc, copper, iron, manganese, calcium, and so on in various types of cells of the reproductive system could affect conception and male fertility rates. The function of trace elements in the male reproductive system could be exerted through some cellular and molecular processes, such as the management of active oxygen species, involvement in the action of membrane channels, regulation of enzyme activity, regulation of gene expression and hormone levels, and modulation of signaling cascades. In this review, we aim to summarize the available evidence on the role of trace elements in improving male reproductive performance. Also, special attention is paid to the cellular aspects and the involved molecular signaling cascades.

Testicular function after non-cytotoxic and immunotherapy drug treatment

BACKGROUND

The effects of novel non-cytotoxic and immunotherapy drugs for cancer treatment on human testicular function have not been studied systematically.

OBJECTIVES

The present study aimed to characterize effects of non-cytotoxic and immunotherapy drugs in patients with cancers who had not been previously treated with gonadotoxic chemo- or radiotherapy.

MATERIALS AND METHODS

This study involved 34 men, not previously treated with gonadotoxic regimens, in a mixed longitudinal (Cohort 1: 19 men about to start and approximately 1 year on non-cytotoxic and immunotherapy treatment) and cross-sectional (Cohort 2: 15 men already on non-cytotoxic and immunotherapy treatment) study using data modeling to estimate within-person time-course changes in testicular exocrine and endocrine functions. Cohort 1 provided 45 paired semen and blood samples (34 prior to and nine during treatment) and Cohort 2 provided 45 sets of samples (15 pre-treatment, 30 on treatment), including six men in Cohort 2 who had pre-treatment spermatozoa cryostorage prior to the study. Men on non-cytotoxic and immunotherapy treatment had undergone a median of 33.5 months long-term treatment.

RESULTS

Spermatozoa output and concentration were reduced by about 50%, with corresponding increases in serum follicle-stimulating hormone and decreases in serum inhibin B. Serum testosterone, luteinizing hormone, and sex hormone-binding globulin were unaffected by non-cytotoxic and immunotherapy treatment.

CONCLUSION

Within limits of the present study of sample size and duration of on-non-cytotoxic and immunotherapy treatment, non-cytotoxic and immunotherapy drugs have a modest effects on testicular exocrine function (sperm production) or its hormonal correlates (follicle-stimulating hormone, inhibin B), with minimal impact on testicular endocrine (testosterone, luteinizing hormone) function.

Adverse drug reactions on male fertility

For several years, fertility disorders have been on the increase worldwide. These disorders affect both sexes, but are more pronounced in men; and in half of cases the etiology is unknown. The role of drugs in male infertility has been little studied to date. Most of the available data comes from experimental animal studies, with all their limitations. With the exception of a few drugs, such as certain anticancer agents, human data are rare. This article describes the mainly drugs known to have deleterious effects on male fertility, the mechanisms leading to these effects and methods used to assess the risk of drug-induced male infertility. It underlines the need for further work in experimental research, clinical trials and post-marketing surveillance to improve our knowledge of drugs that induce male infertility. Although these adverse effects are not life-threatening, they can have a significant impact on patients' lives.

Semen cryopreservation for an oncological reason: a retrospective study

RESEARCH QUESTION

How do cancer type and treatment affect semen quality before and after treatment, and what effect does it have in their clinical management of infertility? Also, what is the rate of patients using cryopreserved semen samples after treatment?

DESIGN

Patients who cryopreserved spermatozoa for oncological reasons between 2000 and 2022 in IVI clinics in Spain were retrospectively reviewed. Semen parameters were analysed before and after treatment, and utilization and destruction rates were calculated. Total motile sperm count (TMSC) was used for assisted reproductive technology (ART) counselling.

RESULTS

A total of 724 patients cryopreserved their semen during the study period. The semen parameters of the cancer patients' semen before and after treatment were heterogeneous, with significant differences between cancer type and semen parameters. The utilization rate was relatively low (0.4%), whereas the destruction rate was 23.1%.

CONCLUSION

Cancer and antineoplastic treatment affect everyone differently. Therefore, sperm cryopreservation should be offered to all patients before starting treatment to ensure their reproductive future. Furthermore, in addition to considering the semen parameters defined by the World Health Organization, it is important to use TMSC in the diagnosis of men to choose appropriate ART according to type of cancer.

P407 hydrogel loaded with nitric oxide microbubbles promotes angiogenesis and functional improvement in testicular transplantation

Prepubertal male patients with cancer have decreased fertility after treatment, but there are currently no suitable means for fertility rescue. Testicular transplantation seems to be a promising treatment. The short-term insufficiency of blood supply after transplantation is the key problem that needs to be solved. In this research, nitric oxide (NO), a gas and small molecule transmitter with the effect of promoting angiogenesis, acted at the site of testicular transplantation. Herein, poloxamer-407 (P407) and lipid microbubble materials served as transport carriers for NO and helped NO to function at the transplant site. P407 hydrogel loaded with NO microbubbles (PNO) slowly released NO in vitro. The three-dimensional space of the hydrogel provided a stable environment for NO microbubbles, which is conducive to the continuous release of NO. In this study, 25% PNO (w/v) was selected, and the gelling temperature was 19.47 °C. The gelling efficiency was relatively high at body temperature. Rheological experiments showed that PNO, at this concentration, had stable mechanical properties. The results from in vivo experiments demonstrated that testicular grafts in the PNO group exhibited a notably accelerated blood flow recovery compared to the other groups. Additionally, the PNO group displayed a significant improvement in reproductive function recovery. In conclusion, PNO exhibited slow release of NO, and a small amount of NO promoted angiogenesis in testicular grafts and restored reproductive function.

Fertility preservation in adult male patients with cancer: a systematic review and meta-analysis

STUDY QUESTION

Does sperm cryopreservation serve as a feasible and effective method for preserving fertility in adult male patients with cancer?

SUMMARY ANSWER

Sperm cryopreservation is an effective fertility preservation method and may benefit patients with cancer.

WHAT IS KNOWN ALREADY

Sperm cryopreservation is the only way to efficiently preserve male fertility. It is an important procedure in ART. Recently, due to remarkable advances in cancer treatment, an increasing number of studies have reported the outcomes of sperm cryopreservation in patients with cancer.

STUDY DESIGN SIZE DURATION

We conducted an extensive literature search for relevant studies published through to 31 December 2021, in the following databases: CENTRAL, CNKI, Cochrane Systematic Reviews, EMBASE, MEDLINE, PUBMED, and Web of Science. The search terms used were '(cryopreservation OR freeze OR freezing OR banking OR cryostorage OR storage) AND (sperm OR semen OR spermatozoon) AND (cancer OR tumor OR malignancy OR neoplasm)'.

PARTICIPANTS/MATERIALS SETTING METHODS

We included all studies that reported offering or attempting to cryopreserve sperm before or during cancer treatment in male patients considered at risk of treatment-related fertility impairment. We evaluated the eligibility of all data in each study. The major exclusion criteria were as follows: non-cancer patients; pediatric and adolescent cancer patients; not reporting the use of cryopreserved sperm; use of fresh semen for ART; not reporting the number of patients with cancer offered sperm cryopreservation or attempting to do so before or during treatment; using an experimental fertility preservation technique such as preservation of testicular tissue or spermatogonial stem cells; duplicate data; abstracts, case report, comments, reviews, or editorials; insufficient data reported. The quality of the included studies was assessed using the Newcastle-Ottawa scale and the Methodological Index for Non-Randomized Studies.

MAIN RESULTS AND THE ROLE OF CHANCE

This meta-analysis included 69 non-randomized studies, with 32 234 patients referred for sperm analysis and 23 178 patients cryopreserving at least one sperm sample. The pooled failed-to-cryopreserve rate was 10% (95% CI, 8-12%), and the sperm disposal and sperm use rates were 23% (95% CI, 16-30%) and 9% (95% CI, 8-10%), respectively. The pregnancy, miscarriage, and delivery rates were 28% (95% CI, 22-33%), 13% (95% CI, 10-17%), and 20% (95% CI, 15-25%), respectively. Subgroup analysis showed higher pregnancy and delivery rates, as well as a lower failed-to-cryopreserve rate, in recent studies compared to those released a decade ago. The studies from Asia reported higher sperm disposal and pregnancy rates than in other continents. Our analysis showed clinical pregnancy rates per cycle of 34% (27-41%), 24% (14-35%), and 9% (5-15%) and delivery rates per cycle of 23% (17-30%), 18% (11-26%), and 5% (1-9%) for ICSI, IVF, and IUI, respectively.

LIMITATIONS REASONS FOR CAUTION

As with all meta-analyses, some limitations should be considered. The first limitation of our study is that the data span 36 years. During this time, the World Health Organization has revised its sperm analysis standards, and other important changes have been made. There is also a limitation in that the outcome does not analyze the correlation between the type of cancer and sperm quality. Many of the earlier studies were limited by small sample sizes and a lack of control groups. Furthermore, almost all studies did not consider the severity of the disease, which could potentially have a substantial impact on the results. Consequently, further research should evaluate the effect of the type of cancer and, in particular, the severity of the condition on sperm quality in order to draw more precise conclusions. Similarly, it is inappropriate that most studies failed to differentiate between patients with different types of tumors and instead drew generalized conclusions that are presumed to apply to all patients with cancer. In the present analysis, we did not have in-depth information on patients' disease, and although extensive efforts were made to conduct a thorough systematic review and meta-analysis of the outcomes for patients with various types of tumors, the results must be acknowledged as being subject to bias. However, the use of average results obtained in each study, without the patient-level data, might also represent a source of bias.

WIDER IMPLICATIONS OF THE FINDINGS

Sperm cryopreservation is an effective fertility preservation method and may benefit patients with cancer. The observed utilization rate of frozen sperm at 9% may underestimate the actual usage, as the short follow-up period is inadequate for obtaining comprehensive data on the use of frozen sperm in young cancer survivors. ART plays an important role in fertility preservation and the achievement of pregnancy, with this meta-analysis showing that ICSI delivers better clinical outcomes than IVF or IUI in patients with cancer undergoing fertility preservation.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the National Natural Science Foundation of China (grant no. 82001634, 81960550), and the China Postdoctoral Science Foundation (2019M661521). There are no competing interests to declare.

REGISTRATION NUMBER

CRID 42022314460.

The Usage of Cryopreserved Reproductive Material in Cancer Patients Undergoing Fertility Preservation Procedures

BACKGROUND

Many cancer treatment methods can affect fertility by damaging the reproductive organs and glands that control fertility. Changes can be temporary or permanent. In order to preserve the fertility of cancer patients and protect the genital organs against gonadotoxicity, methods of fertility preservation are increasingly used. Considering that some patients ultimately decide not to use cryopreserved reproductive material, this review analysed the percentage of post-cancer patients using cryopreserved reproductive material, collected before treatment as part of fertility preservation.

METHODS

A systematic search of studies was carried out in accordance with the Cochrane Collaboration guidelines, based on a previously prepared research protocol. The search was conducted in Medline (via PubMed), Embase (via OVID), and the Cochrane Library. In addition, a manual search was performed for recommendations/clinical practice guidelines regarding fertility preservation in cancer patients.

RESULTS

Twenty-six studies met the inclusion criteria. The studies included in the review discussed the results of cryopreservation of oocytes, embryos, ovarian tissue, and semen. In 10 studies, the usage rate of cryopreserved semen ranged from 2.6% to 21.5%. In the case of cryopreserved female reproductive material, the return/usage rate ranged from 3.1% to 8.7% for oocytes, approx. 9% to 22.4% for embryos, and 6.9% to 30.3% for ovarian tissue. In studies analysing patients' decisions about unused reproductive material, continuation of material storage was most often indicated. Recovering fertility or death of the patient were the main reasons for rejecting cryopreserved semen in the case of men.

CONCLUSION

Fertility preservation before gonadotoxic treatment is widely recommended and increasingly used in cancer patients. The usage rate is an important indicator for monitoring the efficacy of these methods. In all of the methods described in the literature, this indicator did not exceed 31%. It is necessary to create legal and organizational solutions regulating material collection and storage and to create clear paths for its usage in the future, including by other recipients.

Fertility Preservation in Pediatric Age: Future Perspective among Andrological Diseases

Male infertility is a condition that has always been less studied and known than female infertility. Male infertility is increasingly present and increasingly diagnosed. Although several causes are known, to date about 40% of the causes are considered idiopathic. The worldwide denasality can only be slowed if awareness campaigns are implemented on all the diseases that can alter fertile potential, especially in young adolescents. Male infertility is, in addition, associated with several medical conditions. In particular, the association between infertility and testicular cancer, cardiovascular disease, autoimmune diseases, and genetic diseases is well known. For this reason, fertility preservation should not be proposed or be only oncological in nature, as there are several diagnosable pediatric pathologies that are associated with altered fertile potential to whose patients we could offer a gamete preservation pathway. In this paper we propose our experience on fertility preservation in pediatric andrological diseases.

Biomaterials for Testicular Bioengineering: How far have we come and where do we have to go?

Traditional therapeutic interventions aim to restore male fertile potential or preserve sperm viability in severe cases, such as semen cryopreservation, testicular tissue, germ cell transplantation and testicular graft. However, these techniques demonstrate several methodological, clinical, and biological limitations, that impact in their results. In this scenario, reproductive medicine has sought biotechnological alternatives applied for infertility treatment, or to improve gamete preservation and thus increase reproductive rates in vitro and in vivo. One of the main approaches employed is the biomimetic testicular tissue reconstruction, which uses tissue-engineering principles and methodologies. This strategy pursues to mimic the testicular microenvironment, simulating physiological conditions. Such approach allows male gametes maintenance in culture or produce viable grafts that can be transplanted and restore reproductive functions. In this context, the application of several biomaterials have been proposed to be used in artificial biological systems. From synthetic polymers to decellularized matrixes, each biomaterial has advantages and disadvantages regarding its application in cell culture and tissue reconstruction. Therefore, the present review aims to list the progress that has been made and the continued challenges facing testicular regenerative medicine and the preservation of male reproductive capacity, based on the development of tissue bioengineering approaches for testicular tissue microenvironment reconstruction.

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.

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.

Extend the Survival of Human Sperm In Vitro in Non-Freezing Conditions: Damage Mechanisms, Preservation Technologies, and Clinical Applications

Preservation of human spermatozoa in vitro at normothermia or hypothermia maintaining their functions and fertility for several days plays a significant role in reproductive biology and medicine. However, it is well known that human spermatozoa left in vitro deteriorate over time irreversibly as the consequence of various stresses such as the change of osmolarity, energy deficiency, and oxidative damage, leading to substantial limitations including the need for semen examinations, fertility preservation, and assisted reproductive technology. These problems may be addressed with the aid of non-freezing storage techniques. The main and most effective preservation strategies are the partial or total replacement of seminal plasma with culture medium, named as extenders, and temperature-induced metabolic restriction. Semen extenders consist of buffers, osmolytes, and antioxidants, etc. to protect spermatozoa against the above-mentioned adverse factors. Extended preservation of human spermatozoa in vitro has a negative effect on sperm parameters, whereas its effect on ART outcomes remains inconsistent. The storage duration, temperature, and pre-treatment of semen should be determined according to the aims of preservation. Advanced techniques such as nanotechnology and omics have been introduced and show great potential in the lifespan extension of human sperm. It is certain that more patients will benefit from it in the near future. This review provided an overview of the current knowledge and prospects of prolonged non-freezing storage of human sperm in vitro.

Effect of Malignancy on Semen Parameters

Purpose: We aimed to examine how various types of cancer, classified histologically, affect semen quality. Methods: The study group included 313 patients who were diagnosed with cancer and reached for a sperm cryopreservation before a gonadotoxic treatment (PG-Tx group). Their semen parameters were compared to those of two control groups: (a) individuals who attended a fertility investigation and were found to be above the limit of the lower reference value of the WHO 2010 manual (ARL group), and (b) fertile men, whose semen parameters were obtained from the dataset of the WHO 2020 manual. Results: Semen quality was significantly poorer in the PG-Tx group than in the ARL group. Differences included a 65.6% decrease in concentration, a 12.1% decrease in volume, a 72.7% decrease in total count, and a 33.0%, 22.2%, and 24.7% decrease in total motility, rapid motility, and progressive motility, respectively. Linear regression models comparing the PG-Tx and ARL groups revealed that the maximum reduction in total motility and concentration was in men with germ-cell tumors, whereas the minimum reduction was in hematological tumors. Similarly, all sperm quality parameters were significantly lower in the PG-Tx group than in the fertile-men group (p < 0.0001). Conclusions: While the effect of malignancy on semen parameters is debatable, we found that all examined types of cancer significantly impaired sperm quality parameters. Although the median of most semen parameters of patients with cancer were still in the normal WHO range, their fifth percentile, represents men with a delayed time to pregnancy.

Study on cryopreservation of mouse single seminiferous tubule

Cryopreservation of single seminiferous tubule is significant for fertility preservation, especially for male patients with cryptorchidism, Y-chromosome deletion and orchitis. However, there are few studies on cryopreservation of single seminiferous tubule. This study proposes several improved strategies for cryopreservation of single seminiferous tubule in mice. First, single seminiferous tubule was cryopreserved with modified slow freezing and vitrification methods. The results showed that the apoptosis negative rates of spermatogenic cells in single seminiferous tubule with modified slow freezing method were significantly higher than vitrification with plastic slide. Then, plastic slide and two metal vitrification carriers with high thermal conductivity, copper mesh and aluminum foil, were used to vitrify single seminiferous tubule. The metal carriers could improve the outcome of vitrification than plastic slide. The apoptosis negative rates of spermatogenic cells in the aluminum foil group was significantly higher than that in the copper mesh group. Finally, single seminiferous tubule was perfused with CPAs by micro-injection technique and vitrified. The results of cryo-microscopy experiments showed that the ice crystals formed inside the injected seminiferous tubule was reduced during the cooling process, the apoptosis negative rate of spermatocytes, spermatids and Sertoli cells were significantly higher than that of the non-injection group, indicating that the injection technique can effectively improve the effect of vitrification. This study has potential clinical value for in-vitro culture of spermatogonial stem cells and autologous testicular tissue grafting in patients with azoospermia.

Medical therapies causing iatrogenic male infertility

Primum non nocere. As physicians, our goal is to treat illnesses and alleviate suffering; however, in doing so, we can generate new problems in a game of medical whack-a-mole. For some patients, certain consequences or side effects are tolerable, while others may believe they have no alternative. For a male patient with infertility, a thorough history is imperative to elucidate whether the patient has been or is currently being exposed to medications that will harm libido, spermatogenesis, ejaculation, or the hypothalamic-pituitary-testosterone axis. This article will review the most common medications causing iatrogenic male infertility as well as options to minimize or even reverse their impact.

Fertility preservation in men and women: Where are we in 2021? Are we rising to the challenge?

Demand for fertility preservation in women for oncologic, nononcologic, and personal reasons has increased dramatically. Meeting that demand is a major challenge, and we are rising to the challenge. Mature oocyte cryopreservation after ovarian stimulation and ovarian tissue cryopreservation are both methods endorsed by the American Society for Reproductive Medicine (formerly The American Fertility Society), and numerous papers confirmed their efficacy. In girls and women with leukemia or cancers who are at a high risk of ovarian metastasis and who may not be eligible for ovarian tissue transplantation, restoration of fertility can only be achieved by in vitro methods. Male fertility preservation has also become a pressing issue and is extensively reviewed in the present journal issue.