Storage Of Gametes Research Articles

The storage time of cryopreserved human spermatozoa does not affect pathways involved in fertility

BackgroundCryopreservation of human spermatozoa is a widely used technique in the assisted reproduction technology laboratory for the storage of gametes for later use, for the fertility preservation and for sperm donation programs. Cryopreservation can cause damage to membrane, cytoskeletal, acrosome and increased oxidative stress, sperm DNA damage and transcriptome changes. To assess the impact of storage time on the transcriptome of frozen human spermatozoa, semen samples were collected from 24 normospermic donors of whom 13 had cryostored semen for a short-time (1 week) and 11 had cryostored semen for a long-time (median 9 years).ResultsRNA was extracted from each frozen-thawed sperm sample, randomized in pools, and analyzed by microarrays. Five transcripts were in higher abundance in the long-time respect to the short-time storage group. Functional annotation enrichment disclosed that that the length of cryostorage has no effect on critical pathways involved in sperm physiology and function.ConclusionsThe storage time of cryopreserved human spermatozoa does not affect pathways involved in fertility.

Looking into the future: a machine learning powered prediction model for oocyte return rates after cryopreservation

Research questionCould a predictive model, using data from all US fertility clinics reporting to the Society for Assisted Reproductive Technology, estimate the likelihood of patients using their stored oocytes? DesignMultiple learner algorithms, including penalized regressions, random forests, gradient boosting machine, linear discriminant analysis and bootstrap aggregating decision trees were used. Data were split into training and test datasets. Patient demographics, medical and fertility diagnoses, partner information and geographic locations were analysed. ResultsA total of 77,631 oocyte–cryopreservation cycles (2014–2020) were analysed. Patient age averaged 34.5 years. Treatment indications varied: planned (35.6%), gender-related (0.1%), medically indicated (15.5%), oncologic (5.7%) and unknown (42.3%). Infertility diagnoses were less common: unexplained infertility (1.8%), age-related infertility (3.2%), diminished ovarian reserve (9.9%) and endometriosis (1.6%). An ensemble model combining bootstrap aggregation classification and regression trees, stochastic gradient boosting and linear discriminant analysis yielded the highest predictive accuracy on test set (balanced accuracy: 0.83, sensitivity: 0.76, specificity: 0.91), with a receiver operating characteristic curve of 0.90 and precision-recall curve and area under the curve of 0.57. Key factors influencing the likelihood of returning for oocyte use included patient age, presence of a partner, race or ethnicity, the clinic's geographic region and oocyte cryopreservation indication. ConclusionsThis model demonstrated significant predictive accuracy, and is a valuable tool for patient counselling on oocyte cryopreservation. It helps to identify patients more likely to use stored oocytes, enhancing healthcare decision-making and the efficiency of gamete storage programmes. The model can be applied to self-financed and insurance-funded cycles.

Theoretical and applied problems of in vitro fertilization under the legislation of the Russian Federation and the Republic of Belarus

The article deals with the issues of realization of one of the reproductive rights – the use of in vitro fertilization. The right to have children is one of the fundamental constitutional rights. It is emphasized that the use of IVF is a forced measure for spouses (married couples), since it is not possible to conceive children naturally due to medical indications. The point of view that IVF as a result of biomedical advances is becoming more and more predominant; although to a lesser extent, there are voices that have children is a kind of duty to society. It is generally accepted that IVF should not be used to choose the sex of a child, or any of its physical characteristics. This emphasizes the value of the common good, rather than the priority of an individual subject’s choice. The deliberate choice of the sex of an unborn child is a pathway to pernicious gender imbalance. In the context of the moral status of the human embryo, it is recognized that raising an embryo for more than 14 days and then destroying it is ethically unacceptable. Attention is drawn to the disputes arising in practice concerning the possible use of IVF, including after the dissolution of a marriage. Proposals are made to improve civil and other legislation and law enforcement practice. In particular, to provide that heirs under the will and the law may include citizens conceived in accordance with an agreement between a woman and a man to use his biomaterial for in vitro fertilization within six months after his death and born alive after the opening of the inheritance. Free storage of gametes must be provided to law enforcement officers, professional servicemen and servicemen performing duty in «hot spots», employees of the Ministry of Emergency Situations, etc., provided that they do not yet have children. In other cases, they can be kept for a fee.

Effectiveness of glycerol, DMSO and trehalose in the process of cryopreservation of drone semen from the species apis mellifera

Cryopreservation of economically important or endangered animal species is becoming an increasingly popular practice in the field of reproductive biotechnologies. The mass extinction of honey bee (Apis Mellifera) colonies in the last decade requires the use of new chemical components in cryopreservation media for the storage of male gametes. A number of studies demonstrate conflicting data regarding the success rate and cytotoxicity of glycerol and dimethyl sulfoxide and to a lesser extent Trehalose. Dimethyl sulfoxide is an organosulfur compound with low cryotoxicity which transforms into solids below room temperature and this property makes it suitable for cryoprotectant. The kosmotropic properties of glycerol allow it to create hydrogen bonds with water molecules, making it difficult to form intracellular ice crystals in the cryoprotective media. Due to its high-water retaining properties Trehalose can be used as cryoprotectant, but its effectiveness has not yet been thoroughly researched in relation to the cryopreservation of bee drone spermatozoa. The research aims to compare the effectiveness of each of the specified cryoprotectants regarding the preservation of spermatozoa from Apiss Mellifera drones.

Pre-fertilization gamete thermal environment influences reproductive success, unmasking opposing sex-specific responses in Atlantic salmon (Salmo salar).

The environment gametes perform in just before fertilization is increasingly recognized to affect offspring fitness, yet the contributions of male and female gametes and their adaptive significance remain largely unexplored. Here, we investigated gametic thermal plasticity and its effects on hatching success and embryo performance in Atlantic salmon (Salmo salar). Eggs and sperm were incubated overnight at 2°C or 8°C, temperatures within the optimal thermal range of this species. Crosses between warm- and cold-incubated gametes were compared using a full-factorial design, with half of each clutch reared in cold temperatures and the other in warm temperatures. This allowed disentangling single-sex interaction effects when pre-fertilization temperature of gametes mismatched embryonic conditions. Pre-fertilization temperature influenced hatch timing and synchrony, and matching sperm and embryo temperatures resulted in earlier hatching. Warm incubation benefited eggs but harmed sperm, reducing the hatching success and, overall, gametic thermal plasticity did not enhance offspring fitness, indicating vulnerability to thermal changes. We highlight the sensitivity of male gametes to higher temperatures, and that gamete acclimation may not effectively buffer against deleterious effects of thermal fluctuations. From an applied angle, we propose the differential storage of male and female gametes as a tool to enhance sustainability within the hatcheries.

Cryopreservation Cooling Rate Impacts Post-Thaw Sperm Motility and Survival in Litoria booroolongensis.

The cryopreservation and storage of gametes (biobanking) can provide a long-term, low-cost option for the preservation of population genetic diversity and is particularly impactful when applied to manage selective breeding within conservation breeding programs (CBPs). This study aimed to develop a sperm cryopreservation protocol for the critically endangered Booroolong frog (Litoria booroolongensis) to capture founder genetics within the recently established (est. 2019) CBP for this species. Hormone-induced sperm release was achieved using established protocols, and spermic urine samples were collected over a 6-h period. Pooled spermic urine samples (n = 3 males) were divided equally between two cryoprotectant (CPA) treatments and diluted by 1:5 (sperm:CPA) with either 15% (v/v) dimethyl sulfoxide + 1% (w/v) sucrose in simplified amphibian Ringer's (SAR; CPAA) or 10% (v/v) dimethylformamide + 10% (w/v) trehalose dihydrate in SAR (CPAB). The samples were cryopreserved in 0.25 mL straws using either a programmable freezer (FrA) or an adapted dry shipper method (FrB). The thawed samples were activated via dilution in water and assessed for viability and motility using both manual assessment and computer-assisted sperm analysis (CASA; 0 h, 0.5 h post-thaw). Upon activation, the survival and recovery of motility (total motility, forward progression and velocity) of cryopreserved sperm suspensions were higher for sperm preserved using FrB than FrA, regardless of CPA composition. This work supports our long-term goal to pioneer the integration of biobanked cryopreserved sperm with population genetic management to maximize restoration program outcomes for Australian amphibian species.

P-389 "Time is the nurse and breeder of all good": storage periods for embryos and gametes across Europe

Abstract Study question What are the justifications, advantages and disadvantages of contrasting storage regimes for embryos and gametes across Europe? Summary answer Permitted storage periods vary significantly between countries, often lack justification for the limitations they impose, and may compromise individual rights. What is known already Storage periods for gametes and embryos vary significantly across Europe, as does the margin of discretion to grant extensions and adjustments to such periods. This fragmented regulatory landscape adds significant complexity to how cryobanks, clinics and patients are able to plan future treatment options. In addition, it creates an effect which may negatively impact on stakeholders' ability to freely choose where in Europe services are obtained, as well as when: when treatment is delayed because of personal health issues, the clock may not stop ticking on the maximum storage period. Study design, size, duration We have analysed and reviewed the regulation of storage periods in a number of European countries, and have put a particular focus on states which have strongly diverging periods. This assessment examined the policy underpinning the relevant rules, and the consequences of the regime for stakeholders. Our review considered both the legal and ethical aspects of each system and its consequences. Participants/materials, setting, methods Information about storage periods was obtained from legislation, policy documents and publications from national regulators. We also looked at case-law regarding storage issues in certain states. Main results and the role of chance Storage periods for gametes and embryos vary significantly across Europe, as does the margin of discretion to grant extensions and adjustments to such periods. This fragmented regulatory landscape adds significant complexity to how cryobanks, clinics and patients are able to plan future treatment options. In addition, it creates an effect which may negatively impact on stakeholders' ability to freely choose where in Europe services are obtained, as well as when: when treatment is delayed because of personal health issues, such as concurrent cancer treatment, the clock may not stop ticking on the maximum storage period. A regulatory field which so clearly impacts EU Freedom of movement rights, as well as human rights contained both within EU law and the Council of Europe's Convention on Human Rights, should be capable of justification based on robust scientific and clinical evidence. This appears to be inconsistent with the variation we have identified in storage periods across the jurisdictions we have considered. Limitations, reasons for caution The assessment of domestic legal approaches requires an appropriate understanding of the language, as well as of the legal system. Whilst an informative assessment is possible based on policy overviews, a robust assessment of jurisdictions where the official language is not English or German is outwith the paper's scope. Wider implications of the findings The paper's conclusion is that the fragmentation of legal requirements in relation to the storage of embryos and gametes is neither ethically sound nor appropriately legally justified. It impacts negatively on individuals' rights and on commercial interests. More harmonisation is desirable in this field. Trial registration number Not applicable

Assessment of male reproductive traits in endangered leuciscids from the Iberian Peninsula: first attempts to store gametes both at short- and long-term

During the spring of 2022, several endangered leuciscid species (Anaecypris hispanica, Squalius aradensis, Anachondrostoma Occidentale, and Iberochondrostoma lusitanicum) were sampled both at the Vasco da Gama aquarium facilities and in some rivers of the Algarve region, Portugal. Sperm samples were extracted by gentle abdominal pressure and sperm motion parameters were assessed for the first time in four species, using a computerized analysis system. The results obtained showed that spermatozoa kinetic patterns were similar for all 4 species, with high motility and velocity values after the sperm activation time and with a marked decrease after 20. On the other hand, sperm longevity was highly variable between species, with short longevities (around 40 s) for A. hispanica and S. aradensis, and longer longevities (100–120 s) for A. occidentale and I. lusitanicum, which could indicate a latitudinal pattern in terms of sperm longevity. At the same time, morphometric analysis was carried out for the four target species, revealing that spermatozoa showed similar sizes and shapes to other external fertilizers belonging to Leuscididae, with small spherical heads, uniflagellate, and without acrosomes. In addition, a short-term gamete storage trail was performed by diluting sperm in 1:9 (sperm:extender) and storing them at 4ºC. Although the results obtained were uneven among the species studied, the dilution and extender used generated motilities above 40% up to day 4 of storage in S. aradensis and I. lusitanicum, and up to days 1–2 in A. hispanica and A. occidentale, respectively. Finally, gamete cryopreservation trials were also carried out on these threatened species. Although cryopreserved samples showed significantly lower motility than fresh samples, some protocols generate acceptable percentages of viability, DNA integrity, and sperm motility in some species such as I. lusitanicum and A. occidentale. The data revealed that the protocol based on 10% DMSO plus 7.5% egg yolk generated the best results.This study is the first to assess the reproductive traits of wild and captive populations of endangered leuciscids endemic from the Iberian Peninsula, describing the spermatozoa kinetics and developing protocols for managing male gametes both in short- and long-term storage. Outcomes will provide new and useful tools to complement the management and conservation of ex situ breeding programs that are being developed for these four endangered species.

Integrative Proteomics and Transcriptomics Profiles of the Oviduct Reveal the Prolificacy-Related Candidate Biomarkers of Goats (Capra hircus) in Estrous Periods

The oviduct is a dynamic reproductive organ for mammalian reproduction and is required for gamete storage, maturation, fertilization, and early embryonic development, and it directly affects fecundity. However, the molecular regulation of prolificacy occurring in estrous periods remain poorly understood. This study aims to gain a better understanding of the genes involved in regulating goat fecundity in the proteome and transcriptome levels of the oviducts. Twenty female Yunshang black goats (between 2 and 3 years old, weight 52.22 ± 0.43 kg) were divided into high- and low-fecundity groups in the follicular (FH and FL, five individuals per group) and luteal (LH and LL, five individuals per group) phases, respectively. The DIA-based high-resolution mass spectrometry (MS) method was used to quantify proteins in twenty oviducts. A total of 5409 proteins were quantified, and Weighted gene co-expression network analysis (WGCNA) determined that the tan module was highly associated with the high-fecundity trait in the luteal phase, and identified NUP107, ANXA11, COX2, AKP13, and ITF140 as hub proteins. Subsequently, 98 and 167 differentially abundant proteins (DAPs) were identified in the FH vs. FL and LH vs. LL comparison groups, respectively. Parallel reaction monitoring (PRM) was used to validate the results of the proteomics data, and the hub proteins were analyzed with Western blot (WB). In addition, biological adhesion and transporter activity processes were associated with oviductal function, and several proteins that play roles in oviductal communication with gametes or embryos were identified, including CAMSAP3, ITGAM, SYVN1, EMG1, ND5, RING1, CBS, PES1, ELP3, SEC24C, SPP1, and HSPA8. Correlation analysis of proteomics and transcriptomic revealed that the DAPs and differentially expressed genes (DEGs) are commonly involved in the metabolic processes at the follicular phase; they may prepare the oviductal microenvironment for gamete reception; and the MAP kinase activity, estrogen receptor binding, and angiotensin receptor binding terms were enriched in the luteal phase, which may be actively involved in reproductive processes. By generating the proteome data of the oviduct at two critical phases and integrating transcriptome analysis, we uncovered novel aspects of oviductal gene regulation of fecundity and provided a reference for other mammals.

B v University of Aberdeen [2020] CSIH 62: Where there's a will, there's a way.

The area of posthumous reproduction—the process by which assisted reproductive technologies are used to achieve conception, pregnancy, and childbirth after the death of one or both biological parents—raises complex questions for the law. B v University of Aberdeen1 (Aberdeen) adds to an increasing line of cases that grapple with the delicate legal issues involving posthumous reproduction.2 The storage and use of gametes and embryos, including their storage and use posthumously, are regulated by a detailed statutory framework contained principally in the Human Fertilisation and Embryology (HFE) Acts 1990 and 2008. The HFE Act 1990 places significant emphasis on consent,3 which is regarded as one of the twin pillars supporting Parliamentary regulation of this field.4 The specific requirements needed for an effective consent are contained in Schedule (Sch) 3 of the HFE Act 1990, which stipulates, amongst other things, that consent must be in writing.5

In Vitro Embryo Production in Water Buffalo

In vitro embryo production (IVEP) is a promising tool with many applications in producing calves from genetically superior animals desired for propagation and in the conservation and revival of endangered species. The techniques of IVEP were adopted from cattle and refined to suit the water buffalo requirements. From the collection of ovaries from a local abattoir and the collection of oocytes by ovum pick up from live animals, gamete storage, collection techniques, handling of ovaries and oocytes to keep the viability and developmental competence, selection of oocytes to the type of culture media and in vitro culture condition, and treatment of the sperm cells for in vitro fertilization are all-important components of the process that requires careful and precise action to ensure success. Trials on intracytoplasmic injection, the use of sex-sorted sperm cells as a tool for producing sex-predetermined embryos, and the somatic cell nuclear transfer are methods that can be used to produce embryos in vitro. This paper provides the important considerations involved in the production of healthy live calves out of in vitro-produced water buffalo embryos.

Extended in vitro storage of eggs and milt increases maternal but not paternal variation in embryo viability of landlocked Atlantic salmon (Salmo salar m. sebago)

Appropriate fertilization practices play a crucial role in the maintenance of genetic diversity within captive fish broodstocks. We assessed the influence of in vitro storage of gametes (0-, 7- and 14-days post-stripping) at 1 °C on ovarian fluid pH, sperm motility, and embryo viability in the critically endangered Finnish landlocked salmon (Salmo salar m. sebago) population. A repeated full-factorial design used in both sperm-ovarian fluid activation analyses and fertilizations allowed us to separate the effects of female, male and their interaction on gamete quality and embryo survival across storage times. The ovarian fluid pH decreased most significantly during the first week of storage and showed considerable variation among females. The decrease of sperm motility varied across males, females and male–female (sperm-ovarian fluid) combinations. The mean proportion of viable embryos was initially 96.4%, but dropped to 45.5% after 7 days, and to 13.1% after 14 days of gamete storage. Embryo viability responses to gamete storage time predominantly increased among- and within-female variation but also showed major differences between female × male combinations (non-additive genetic effects). Interestingly, embryo viability showed virtually complete re-ranking (change of order) among full-sib families between the first two fertilization times (rs = − 0.03) but consistency between the first and last times (rs = 0.59). Overall, our results indicate that even when the primary aim is to maximize the genetic diversity of endangered fish populations, it may be advisable to prioritize minimal egg storage time rather than maximizing the number of parental combinations in fertilizations.

Improving Embryologists’ Sleep Quality: Implementation of a Weight-Based Monitoring System for Gamete and Embryo Cryostorage

Background: Storage of gametes and embryos in our laboratories represents the highest concentration of risk for an ART clinic. A single storage tank may contain material of several hundred patients and vacuum failure is a scenario that haunts embryologists’ nightmares. Temperature sensors are currently the most prevalent mechanism for ‘alarming’ storage tanks, however, such approaches are akin to closing the gate after the horses have bolted. Aim: To assess the implementation of a fully redundant, weight-based monitoring system for ensuring the security of liquid nitrogen storage tanks in a high-capacity ART unit. Method: Forty flat-bed scales were fitted with alarm conversion units allowing a standard ‘open/closed’ alarm output to be relayed in the event a reading fell below the user defined weight limit. Output was routed through a security monitoring system via phone line and mobile-SIM, with no overlap of the existing, internet-based temperature probe system. Relationship between liquid nitrogen level (HC35 vessel), tank weight and temperature reading (probe positioned at top of canister), was established by sequential measurements. Results: Addition of the flat bed scales proved minimally disruptive to the space allocation per tank, requiring no additional ‘width’ but a slight increase in ‘depth’ behind tanks to accommodate the screen support. As expected, a clear, linear relationship was evident between liquid nitrogen level and tank weight, with every 1cm drop in liquid nitrogen equating to approximately 0.5kg weight loss. Concerningly, the temperature probe remained below -190∘ with just 0.5cm of liquid nitrogen remaining, only rising above the alarm trigger threshold once nitrogen had fully evaporated, resulting in a precipitous rise to above devitrification temperature in a matter of hours. Conclusion: Introducing a weight-based tank monitoring system is both feasible and effective. This system provides vastly superior performance in the timely identification of impending tank failure, allowing ample opportunity to ensure safe relocation of material.

Implications of Posthumous Care — The Experience of the Surviving Partner

Background: Posthumous assisted conception remains controversial, and in providing this form of care, it is critical that fertility clinics consider the potential effects on the welfare of the person to be born, as well as any existing children already within the family unit. The NHMRC provides clear clinical guidelines for the collection, storage and use of gametes or embryos posthumously, however care providers rarely have an opportunity to gain a genuine understanding of the experience for a bereaved spouse undertaking this form of treatment. Aim: To explore the social and psychological implications of undertaking posthumous care, for the surviving partner of the deceased person, their broader family and the child. Method: Brief examination of the social and psychological implications of posthumous care. Personal case presentation by a surviving partner who has completed treatment using posthumous care. Conclusion: The personal experience of undertaking posthumous care will be examined, as provided within the relevant NHMRC clinical guidelines.

Demographics and Cycle Outcomes of Transgender Patients Accessing Gamete Services at Monash IVF Victoria

Background: Since 2003 an increasing number of transgender patients are electing to store gametes prior to transitioning and/or utilising ART services at Monash IVF Victoria. Aim: The aim of this study was to determine the number of transgender patients accessing gamete storage and utilisation services, as well as their cycle outcomes. Methodology: A retrospective study of frozen gamete usage of 48 patients collected between 2003-2021 was undertaken. Results: Trans-female patients were the most common cohort, with 37 patients (16-49yrs, mean age 25.9± 7.7) undertaking semen freezing and two (13yrs and 17yrs) surgical sperm retrieval prior to transitioning. Between 2003-2010 and 2011-2021 six (15.4%) and 33 (84.6%) patients respectively used this treatment. On average 2.3± 2.0 ejaculates/patient were frozen. At freezing 13 (35.1%) patients had >1 ejaculate with a low sperm count and 23 patients (62%) low sperm motility compared to WHO criteria; data were unavailable if patients had already commenced hormonal therapy. Four patients (10.8%) elected to register as sperm donors and their sperm used, while only four (10.8%) trans -female patients have returned, 2-7 years later (mean 5.3± 2.2 years) with a cis -female partner to utilise their gametes; two achieving a live birth. In contrast, nine trans -male patients (20-29yrs, mean age 23.9± 2.6yrs) undertook oocyte collection; one (11.1%) had treatment in 2003-2010 and eight (88.9%) between 2011-2021. On average 1.4± 0.7 egg freezing cycles/patient were conducted, with 4-30 eggs frozen/collection (mean 14.4± 7.1). One patient donated their oocytes to their cis- female partner in an ICSI cycle 7 years after freezing and achieved one live birth. Conclusion: Gamete cryopreservation is a valuable service for transitioning patients wishing to preserve fertility; numbers are increasing, with low utilisation to date and successful outcomes recorded. Exploring transgender patient experiences and ART service uptake will provide vital feedback to tailor an inclusive fertility journey at our clinics.

Fertility preservation for transgender individuals

Lay summaryTransgender people are just as able to be good parents as anyone else. The treatment involved in addressing their gender dysphoria usually removes their natural fertility and if they want to preserve their fertility, they will need gamete storage. The technology needed to provide gamete storage for transfolk is not any different from anyone else but the clinic setup, human interactions and the approach used need to be sensitive and require everyone in the clinic to understand the issues and behave accordingly if high-quality service is to be provided.

Effect of Application of Different Activation Media on Fertilization and Embryo Survival of Northern Pike, (Esox lucius) under Hatchery Conditions.

Simple SummaryNorthern pike is one of the most important freshwater species that is produced mainly for restocking. It is economically and ecologically valuable and an important species in recreational fisheries as a top predator in fresh waters. Although the artificial reproduction of this species seems easy, it still poses many difficulties. This is why research is constantly being conducted to improve artificial reproduction, the short-term storage of gametes, and fertilization techniques. The aim of this study was to use various activation media to increase fertilization rates in this species. The results obtained indicate that the use of selected activation media in field hatcheries can significantly increase the reproductive efficiency of northern pike.One of the finfish species that European and North American breeders are most interested in is the northern pike, Esox lucius. Artificial reproduction and the production of viable larvae has a huge impact on further culture. The quality of stripped gametes is highly variable. Therefore, it is important to use gametes with maximum efficiency, which has a direct impact on the amount of stocking material produced and therefore on the economics of production. The aim of this study was to compare northern pike fertilization efficiency, expressed as the survival rate of embryos until hatching. In the first experiment, the highest percentage of hatched embryos was observed in groups of eggs fertilized in a saline diluent prepared with deionized water (after reverse osmosis: group D), at 61.2% and 56.5% in the NaCl5-D and NaCl6-D groups, respectively. The highest percentage of hatched embryos in the second experiment was observed in the egg groups activated with Woynarovich solution (V) at 75.5% and 74.7% for V-D (D—deionized water) and V-T (T—tap water), respectively. In all cases, preparing the activation medium using T versus D water resulted in lower fertilization percentages and lower percentages of hatched larvae. At the same time, two variants (V and B1—Billard solution) were tested during mass spawning in three hatcheries using hatchery water (tap water). The results showed that repeatability was the highest when using activation medium B1.

Long-term storage of gametes and gonadal tissues at room temperatures: the end of the ice age?

Long-term preservation of viable spermatozoa, eggs, embryos, and gonadal tissues of good quality is essential in human reproductive medicine and for the population management of livestock, laboratory, and wild species. Instead of using freezing temperatures, encouraging findings indicate that structures and functions of gametes or gonadal tissues can be suspended in trehalose glass after dehydration and then preserved at supra-zero temperatures. As a new era in fertility preservation and biobanking is about to start, the advantages, needs, and implications of germplasm storage at room temperatures must be carefully examined. Although very promising, the development of alternate biobanking strategies does not necessarily mean that the end of the "ice age" (cryopreservation) is near.

Long‑term storage of gametes and gonadal tissues at room temperatures: the end of the ice age?

Long‑term storage of gametes and gonadal tissues at room temperatures: the end of the ice age?

Oocyte Cryopreservation in Domestic Animals and Humans: Principles, Techniques and Updated Outcomes.

Simple SummaryOocyte cryopreservation is the most powerful technique for preserving the genetic potential of individual females. However, the recent outcomes of this technology in terms of viability, fertilizing ability, embryo development and pregnancy remain poor. The high sensitivity of the oocytes to freezing has been correlated with the profound dynamics of oocyte structures and functions. As a result, cryoinjury inevitably occurs at several cellular levels, which is indeed detrimental to cell viability and subsequent development. Advancement in the improvement of freezing technology via modifications to freezing technique and development of novel cryodevices plays a central role in mitigating cryoinjury and efficiently empowering the outcomes of oocyte cryopreservation. However, empirical study and optimizations of the techniques are generally required for cryopreservation of oocytes from particular species.Oocyte cryopreservation plays important roles in basic research and the application of models for genetic preservation and in clinical situations. This technology provides long-term storage of gametes for genetic banking and subsequent use with other assisted reproductive technologies. Until recently, oocytes have remained the most difficult cell type to freeze, as the oocytes per se are large with limited surface area to cytoplasm ratio. They are also highly sensitive to damage during cryopreservation, and therefore the success rate of oocyte cryopreservation is generally poor when compared to noncryopreserved oocytes. Although advancement in oocyte cryopreservation has progressed rapidly for decades, the improvement of cryosurvival and clinical outcomes is still required. This review focuses on the principles, techniques, outcomes and prospects of oocyte cryopreservation in domestic animals and humans.