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

Cancer and oncologic therapies can have significant adverse effects on male reproductive potential, leaving many men permanently infertile. Fertility preservation has emerged as a key survivorship issue over the past 20 years, and numerous professional societies have published guidelines calling for fertility preservation to become a routine component of oncologic care. Most males with cancer are able to produce a semen specimen for fertility preservation, but numerous other methods of sperm procurement are available for patients who cannot provide a sufficient sample. Despite these options, fertility preservation will remain a challenge for prepubertal boys and men without sperm production. For these patients, experimental and investigational approaches offer the hope that one day they will translate to the clinical arena, offering additional pathways for successful fertility preservation care.

Protective Effects of Curcumin on the Outcome of Cryopreservation in Human Sperm.

Cryopreservation causes decreased sperm fertility potential due to reactive oxygen species (ROS) production and physical-chemical damage, resulting in reduced sperm viability and motility. The addition of antioxidants to freezing media could protect sperm from cryo-damage, counteracting the harmful effects of ROS. The aim of this study was to assess the effects of curcumin supplementation in freezing medium on preventing cryo-damage in human semen. Semen samples collected from fertile men were cryopreserved in freezing medium supplemented with different concentrations of curcumin (2.5, 5, 10, and 20 µM). After freezing-thawing, sperm parameters, DNA fragmentation, intracellular ROS, and glutathione peroxidase 4 (GPX4) gene expression were evaluated. Supplementation with 20 µM curcumin in freezing medium caused increases in progressive and nonprogressive motility and significant reductions in intracellular ROS and DNA fragmentation in frozen-thawed sperm cells. Following cryopreservation, GPX4 mRNA expression was significantly upregulated in thawed semen supplemented with 20 µM curcumin compared to the control. The results showed that curcumin supplementation in freezing medium was protective against human sperm parameters and sperm DNA, counteracting oxidative damage induced by the freeze-thaw process.

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.

Human sperm vitrification: the state of the art.

Sperm cryopreservation has been widely used in assisted reproductive technology (ART) and has resulted in millions of live births. Two principal approaches have been adopted: conventional (slow) freezing and vitrification. As a traditional technique, slow freezing has been successfully employed and widely used at ART clinics whereas the latter, a process to solidify liquid into an amorphous or glassy state, may become a faster alternative method of sperm cryopreservation with significant benefits in regard to simple equipment and applicability to fertility centers. Sperm vitrification has its own limitations. Firstly, small volume of load is usually plunged to liquid nitrogen to achieve high cooling rate, which makes large volume sample cryopreservation less feasible. Secondly, direct contact with liquid nitrogen increases the potential risk of contamination. Recently, new carriers have been developed to facilitate improved control over the volume and speed, and new strategies have been implemented to minimize the contamination risk. In summary, although sperm vitrification has not yet been applied in routine sperm cryopreservation, its potential as a standard procedure is growing.

Update on advanced semen-processing technologies and their application for in vitro embryo production in horses.

The increased commercialisation of intracytoplasmic sperm injection (ICSI) in horses creates more opportunities to incorporate advanced reproductive technologies, such as sex-sorted, refrozen and lyophilised spermatozoa, into a breeding program. This paper reviews the status of these semen-handling technologies in light of their use in equine ICSI programs. Pregnancies have been achieved from each of these advanced technologies when combined with ICSI in horses, but refinements in the semen-handling processes underpinning these technologies are currently being explored to produce more reliable and practical improvements in the results from equine ICSI.

Purging of malignant cell contamination prior to spermatogonia stem cell autotransplantation to preserve fertility: progress & prospects.

PURPOSE OF REVIEW: This systematic review evaluates the state of the art in terms of strategies used to detect and remove contaminated malignant cells from testicular biopsy prior to spermatogonia stem cells (SSCs) autotransplantation to restore fertility. RECENT FINDINGS: Several trials have been done in past two decades to determine the reliable methods of detecting and purging cancer cells prior to SSCs autotransplantation. SUMMARY: The success in treating childhood cancer has dramatically increased over the past few decades. This leads to increasing demand for a method of fertility preservation for patients with pediatric cancer, as many cancer therapies can be gonadotoxic. Storing the SSCs prior to chemo- or radiation therapies and transplanting them back has been tested as a method of restoring fertility in rodents and nonhuman primate models. This has promise for restoring fertility in childhood cancer survivors. One of the major concerns is the possibility of malignant cell presence in testicular tissue biopsies that could re-introduce cancer to the patient after SSCs autotransplantation. Non-solid cancers - especially hematologic malignancies - have the risk of being transplanted back into patients after SSCs cryopreservation even if they were only present in small number in the stored testicular tissue biopsy.

Spermatozoa Cryopreservation: State of Art and Future in Small Ruminants.

The cryotolerance of farm animal spermatozoa varies according to their specific features, such as size, shape, and lipid composition. Thus, it is impossible to develop a standardized freezing procedure for different kinds of livestock species. The establishment of an efficient semen cryopreservation procedure will facilitate long-term conservation of small ruminant genetic resources and extension of artificial insemination in daily production. Different from sheep, goat seminal plasma contains a phospholipase, which can affect spermatozoa viability through interaction with milk or egg yolk. Currently, soybean lecithin is a viable alternative that replaces the components of animal origin in freezing extenders for goat semen. In addition, vitrification or freeze-drying may act as another alternative to replace traditional cryopreservation. However, these two methods, especially freeze-drying, may require the aid of the intracytoplasmic spermatozoa injection technology. Furthermore, the cryoinjury mechanism of mammalian spermatozoa has remained unclear until now. The emergence of proteomics and transcriptomics may provide some inspiration concerning this problem. In this review, we summarize the state of art relating to small ruminant semen cryopreservation, mainly focusing on the current status of the freezing procedures. In the meantime, some highlights such as protectants, vitrification, and freeze-drying are also reviewed. Finally, the future perspectives in the field of small ruminant spermatozoa preservation are discussed.

Semen Cryopreservation and Banking for the Conservation of Neotropical Carnivores.

Neotropical carnivores include a large number of threatened and endangered species. It is critical to develop conservation efforts to ensure the sustainability of populations in situ and ex situ. The highest priorities are to protect natural habitats and better understand the biology of rare species. Conservation efforts also are directed toward the implementation of breeding programs and the development of reproductive biotechnologies in which the cryopreservation of male gametes plays a major role. It also is fundamental to create semen banks that contribute to maintaining genetic diversity in small and endangered populations. The present article aims at reviewing the state of the art in cryopreservation of semen from neotropical carnivores and discuss the development of systematic banking for the conservation of these understudied species.

Sperm cryopreservation of transgender individuals: trends and findings in the past decade.

OBJECTIVES: Awareness and acceptance of transgenderism have increased in the last two decades. There is limited literature regarding the incidence and semen characteristics of transwomen banking spermatozoa. We sought to assess the incidence of sperm cryopreservation of transgender individuals compared with the cisgender population in the last 10 years. Semen parameters were also compared between the two groups. MATERIALS AND METHODS: We performed a retrospective analysis of sperm cryopreservation performed at a single center from 2006 through 2016. Using available data on indications for banking and prior hormonal therapy status, we isolated healthy transgender and cisgender cohorts for semen parameter comparison. Linear regression was used to compare the incidence trends. Semen parameters were compared using the generalized estimating equations method. The rates of semen parameter abnormality of each group were compared using chi-square test. Semen parameter abnormalities were defined using WHO 2010 reference values. RESULTS: We analyzed 194 transgender samples and 2327 cisgender samples for a total of 84 unique transgender sperm bankers and 1398 unique cisgender sperm bankers. The number of transgender sperm bankers increased relative to cisgender sperm bankers from 2006 to 2016. Following exclusion of cisgender sperm bankers with health issues that might impact semen quality and transgender sperm bankers with known prior hormonal therapy, we compared the semen parameters of 141 healthy cisgender sperm bankers and 78 healthy transgender sperm bankers. The transgender sperm bankers demonstrated lower sperm concentration, total motile sperm count, and post-thaw sperm parameters. The transgender sperm bankers also demonstrated a higher incidence of oligozoospermia. CONCLUSIONS: This is the largest report to date on the incidence of transgender sperm cryopreservation and comparison of semen characteristics with cisgender sperm bankers. The data reveal an increased incidence of transgender sperm banking as well as poorer semen parameters of transgender individuals compared with cisgender controls.

SEOM Clinical Guideline of fertility preservation and reproduction in cancer patients (2016)

Chemotherapy and radiotherapy often result in reduced fertility in cancer patients. With increasing survival rates, fertility is an important quality-of-life concern for many young cancer patients. Around 70-75% of young cancer survivors are interested in parenthood but the numbers of patients who access fertility preservation techniques prior to treatment are significantly lower. Moreover, despite existing guidelines, healthcare professionals do not address fertility preservation issues adequately. There is a critical need for improvements in clinical care to ensure patients are well informed about infertility risks and fertility preservation options and to support them in their reproductive decision-making prior to cancer treatment (AU)

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Evolving trends in cryopreservation and parameters influencing semen extender preparation - a prospective review.

BACKGROUND: Cryopreservation is a technique by which, semen can be preserved to subzero temperature, usually at -196° C. The freezing of semen desires vitrification mediators that diminish wreck to the cells (spermatozoan) during the freeze and thaw process. Using cryopreservation, the quality of the semen has been increased in the latest years, by which the achievement rate for the insemination techniques has increased in an agreed way. The area need to be focused is to enhance the quality of the semen extender preparation before cryopreservation. Many researchers are working in the area of cryopreservation of human semen with different semen extenders. Several parameters influence the properties of semen extender essential for better post thaw results. This review is mainly focused on a range of parameters which influence the best semen extender for cryopreservation that includes glycerol and its importance, buffer and novel usage of antimicrobial peptides as antimicrobial agents.

Assisted reproduction with gametes and embryos: what research is needed and fundable?

Principles for selecting future research projects include interests of investigators, fundability, potential applications, ethical considerations, being able to formulate testable hypotheses and choosing the best models, including selection of the most appropriate species. The following 10 areas of assisted reproduction seem especially appropriate for further research: efficacious capacitation of bovine spermatozoa in vitro; improved in vitro bovine oocyte maturation; decreasing variability and increasing efficacy of bovine superovulation; improved fertility of sexed semen; improving equine IVF; improving cryopreservation of rooster spermatozoa; understanding differences between males in success of sperm cryopreservation and reasons for success in competitive fertilisation; mechanisms of reprogramming somatic cell nuclei after nuclear transfer; regulation of differentiation of ovarian primordial follicles; and means by which spermatozoa maintain fertility during storage in the epididymis. Issues are species specific for several of these topics, in most cases because the biology is species specific.

Sperm cryopreservation in adolescents and young adults with cancer: results of the French national sperm banking network (CECOS).

OBJECTIVE: To determine the feasibility of fertility preservation in adolescent males with cancer. DESIGN: Large multicenter retrospective study of male patients ≤20 years from 23 centers of a national network of sperm banks over a 34-year period. SETTING: Sperm banks. PATIENT(S): A total of 4,345 boys and young men aged 11 to 20 years. INTERVENTION(S): Age, cancer diagnosis, feasibility of sperm banking, and sperm parameters. MAIN OUTCOME MEASURE(S): Description of patients, and success of their fertility preservation. RESULT(S): We observed a mean yearly increase in referred patients of 9.5% (95% confidence interval, 9.1%-9.8%) between 1973 and 2007. Over the study period, the percentage of younger cancer patients who banked their sperm increased, especially in the 11-14 year age group, rising from 1% in 1986 to 9% in 2006. We found that 4,314 patients attempted to produce a semen sample, 4,004 succeeded, and sperm was banked for 3,616. The mean total sperm count was 61.75 × 10(6) for the 11-14 year age group, and 138.81 × 10(6) for the 18-20 year age group. It was noteworthy that intercenter variations in practices involving young patients seeking to preserve their fertility before cancer therapy were observed within this national network. CONCLUSION(S): Our results emphasize the need for decisive changes in public health policy to facilitate the access to reproductive health-care for young cancer patients.

Trends and usage in a London National Health Service Sperm Bank for cancer patients.

Sperm cryopreservation is the only method currently available that offers men with cancer insurance against sterilising iatrogenic treatments. We carried out two cohort and cross-sectional audits to identify trends with sperm cryopreservation referral rates and sample usage rates for men diagnosed with cancer and who banked sperm at The Andrology Laboratory, Hammersmith Hospital, Imperial College NHS Trust. These retrospective audits revealed that a total of 4362 men with cancer successfully banked sperm between 1976 and 2013. Truncating the dataset to 2009 to allow for lag times between storage and use, the overall sample usage rate for cancer patients was 6.0% with 75 live births. Increased median age at referral influences the cancer profile of men seen at the bank, which is highlighted by a disproportionate rise in the number of men with prostate cancer. Among men who use banked sperm, a large rise in the use of intracytoplasmic sperm injection has occurred over time. The number of patients requiring the service is sharply increasing year on year as are the number of patients who go on to use their sample in assisted conception. The historical use rates of frozen sperm are likely to be significant underestimations of future use.

The latest improvements in the mouse sperm preservation.

Sperm preservation is an important technique for maintaining valuable genetic resources in biomedical research and wildlife. In the mouse, the sperm cryopreservation method has been established and adopted by large-scale sperm preservation projects in cryobanks. Recently, a new sperm preservation method using freeze-drying has been studied in various mammals. Freeze-drying is the ultimate method by which sperm can be preserved long term in a refrigerator (4 °C). And it is possible to realize easy and safe transportation of sperm at an ambient temperature that requires neither liquid nitrogen nor dry ice. Furthermore, it has been demonstrated that the fertilizing ability of sperm cryopreserved or freeze-dried by the methods described in this chapter is well maintained during long-term preservation. This chapter introduces the latest protocols for cryopreservation and freeze-drying of mouse sperm, and the anticipated results of the fertilizing ability of these sperm preserved long-term.

Challenging endeavour for preservation of freeze-dried mammalian spermatozoa.

Freeze-drying (lyophilization) has been proposed as an alternative method for sperm preservation to overcome the disadvantages of the current cryopreservation method such as the high maintenance cost of frozen stocks, the problems associated with transportation of frozen materials and the potential risk of total loss of the frozen stock. Since freeze-dried spermatozoa after rehydration lose their motility, which is an essential requirement to complete physiological fertilization, a relatively difficult microinsemination technique must be applied to rehydrated spermatozoa. Theoretically, it has been supposed that freeze-dried spermatozoa could maintain their functions and abilities to interact with the oocyte cytoplasm after prolonged storage at refrigerator temperature. However, sufficient yield of transferable blastocysts and production of live offspring derived from freeze-dried sperm samples are still subjects to be challenged and overcome in large domestic species.

Recent advances in boar semen cryopreservation.

Since 35 years ago boar semen has been frozen and used for artificial insemination (AI). However, fertility of cryopreserved porcine sperm has consistently been low as boar sperm are more sensitive to cellular stress imposed by changing osmotic balance, oxidative stress, low-temperature exposure, cryo-protectant intoxication etc. and are less able to compensate for these deficiencies at commercially applicable dosages. Additionally, differences in sperm freezability among individuals are well known. Here we review current advances on tests to screen sperm quality post-thaw, on ways of diminishing individual boar effects, on improvement of cryo-protection by novel extender components, on packaging and freezing protocols and freezing and thawing methods, and on the handling of sexed boar sperm. Major advances have been registered, which have improved cryo-survival and the capacity to process boar semen for commercial AI.

Cryopreservation of boar semen and its future importance to the industry.

Whereas AI has arguably been the most important management tool leading to improved herd productivity, long-term storage of semen brings forth additional advantages to producers of agriculturally important animals and the AI industry. Semen cryopreservation greatly facilitates the distribution of agriculturally desirable genes, rapidly increasing herd productivity. Of particular importance to the pig industry, the use of frozen semen would help to control transmission of certain pathogens, thereby protecting the health status of the herd. Moreover, a reserve of cryopreserved semen would minimize the effects of a sudden outbreak of a contagious illness or a natural disaster. Successful cryopreservation of boar semen is necessary for international sales. Finally, effective gene banking depends on the availability of functional, cryopreserved germplasm. Despite these potential advantages of long-term semen storage, porcine sperm are notoriously sensitive to cold temperatures, and frozen-thawed semen is not routinely used by the industry. The objective of our laboratories is to develop protocols for efficient long-term storage of porcine semen using cryopreservation. We hypothesize that since the sperm plasma membrane is the primary site of cold-induced damage, reinforcing the membranes with molecules having particular properties, such as cholesterol, will improve the ability of boar sperm to withstand cold temperatures and cryopreservation protocols. Based on our data, such approaches should help alleviate the problems with sperm function after cooling, thereby resulting in better survival and motility characteristics, and reduced non-regulated capacitation and spontaneous acrosome reactions.

Cryobiological determinants of frozen semen quality, with special reference to stallion.

Success in cryopreserving stallion semen has been very variable. Several different freezing regimes have been published. However, because extenders and procedures used in each regime have differed, direct comparison of these techniques has been very difficult, and controlled studies comparing different techniques have not been reported. A number of different factors affect sperm cryosurvival. In this article we review briefly current cryopreservation procedures for stallion semen, and then in more detail cryobiological determinants of sperm function, and mechanisms of cryoinjury and cryoprotectant action. Specific attention is given to data relating to stallion sperm. The complexity of sperm cell biology is believed to be an important factor when developing improvements in stallion semen cryopreservation. It may be assumed that impairment of cell function resulting from cold and osmotic shock is a main source of stallion sperm sensitivity to conventional freezing procedures. Further physiological studies on stallion sperm are required to understand the mechanisms by which cryopreservation alters sperm function and influences selection of sperm with higher fertilizing potential. Such studies should focus especially on the processes involved in sperm volume regulation, sperm-oviduct interaction, capacitation and cellular signalling, and on the alterations in these processes caused by cryopreservation.