Comparison between slow freezing and vitrification of ovarian tissue cryopreservation in assigned female at birth transgender people receiving testosterone therapy: data on histological and viability parameters

The walnut-derived peptide TW-7 improves mouse parthenogenetic embryo development of vitrified MII oocytes potentially by promoting histone lactylation

BACKGROUND

Previous studies have shown that the vitrification of metaphase II (MII) oocytes significantly represses their developmental potential. Abnormally increased oxidative stress is the probable factor; however, the underlying mechanism remains unclear. The walnut-derived peptide TW-7 was initially isolated and purified from walnut protein hydrolysate. Accumulating evidences implied that TW-7 was a powerful antioxidant, while its prospective application in oocyte cryopreservation has not been reported.

RESULT

Here, we found that parthenogenetic activation (PA) zygotes derived from vitrified MII oocytes showed elevated ROS level and delayed progression of pronucleus formation. Addition of 25 μmol/L TW-7 in warming, recovery, PA, and embryo culture medium could alleviate oxidative stress in PA zygotes from vitrified mouse MII oocytes, furtherly increase proteins related to histone lactylation such as LDHA, LDHB, and EP300 and finally improve histone lactylation in PA zygotes. The elevated histone lactylation facilitated the expression of minor zygotic genome activation (ZGA) genes and preimplantation embryo development.

CONCLUSIONS

Our findings revealed the mechanism of oxidative stress inducing repressed development of PA embryos from vitrified mouse MII oocytes and found a potent and easy-obtained short peptide that could significantly rescue the decreased developmental potential of vitrified oocytes, which would potentially contribute to reproductive medicine, animal protection, and breeding.

Barriers to fertility preservation access in transgender and gender diverse adolescents: a narrative review

Fertility preservation (FP) involves the cryopreservation of gametes, embryos, and/or gonadal tissue oocytes, for future use in family building. FP as part of a comprehensive approach to care of transgender and gender diverse (TGD) individuals is an understudied topic. Current evidence indicates that gender affirming therapies may increase the risk for infertility. As a result, TGD individuals, including adolescents, should receive counseling regarding FP prior to beginning gender affirming treatment. Many barriers exist to TGD adolescents receiving FP counseling and undergoing FP if desired. The objective of this narrative review is to summarize the literature regarding the desire for FP in TGD adolescents, the barriers to TGD adolescents in accessing of FP, and to discuss potential interventions for alleviation of such barriers. A literature search using the following Medical Subject Headings search terms: 'transgender persons' and 'fertility preservation' and 'adolescents' was conducted via searching PubMed. Additional articles were located via reference review. Included articles consist of qualitative and quantitative research and society guidelines. Articles from inception to 1st July 2023 were included. The results of the literature search have been summarized into the format of a narrative review. Key barriers to FP for TGD adolescents include inconsistencies in form and timing of counseling, potential worsening of gender dysphoria with FP treatment, high cost of treatment, limited research on FP outcomes, and legal barriers. Intersectionality between gender identity and other forms of minority status can compound these barriers to FP and healthcare in general. Barriers to TGD adolescents accessing FP are significant. Increased research is needed upon methods to mitigate these barriers. Solutions include increasing uniformity and timing of FP counseling by varying health care providers, advocacy efforts to mitigate legal and financial barriers, increased research efforts in FP outcomes, and increased cultural competency in clinics offering FP care to TGD adolescents.

Evaluation of heat transfer in porous scaffolds under cryogenic treatment: a numerical study

The present work had evaluated the effect of cryogenic treatment (233 K) on the degradation of polymeric biomaterial using a numerical model. The study on effect of cryogenic temperature on mechanical properties of cell-seeded biomaterials is very limited. However, no study had reported material degradation evaluation. Different structures of silk-fibroin-poly-electrolyte complex (SFPEC) scaffolds had been designed by varying hole distance and hole diameter, with reference to existing literature. The size of scaffolds were maintained at 5 [Formula: see text] 5 mm2. Current study evaluates the effect of cryogenic temperature on mechanical properties (corelated to degradation) of scaffold. Six parameters related to scaffold degradation: heat transfer, deformation gradient, stress, strain, strain tensor, and displacement gradient were analyzed for three different cooling rates (- 5 K/min, - 2 K/min, and - 1 K/min). Scaffold degradation had been evaluated in the presence of water and four different concentrations of cryoprotectant solution. Heat distribution at various points (points_base, point_wall and point_core) on the region of interest (ROI) was found similar for different cooling rates of the system. Thermal stress was found developing proportional to cooling rate, which leads to minimal variation in thermal stress over time. Strain tensor was found gradually decreasing due to attenuating response of deformation gradient. In addition to that, dipping down of cryogenic temperature had prohibited the movement of molecules in the crystalline structure which had restricting the displacement gradient. It was found that uniform distribution of desired heat at different cooling rates has the ability to minimize the responses of other scaffold degradation parameters. It was found that the rates of change in stress, strain, and strain tensor were minimal at different concentrations of cryoprotectant. The present study had predicted the degradation behavior of PEC scaffold under cryogenic temperature on the basis of explicit mechanical properties.

Perfusion and Ultrasonication Produce a Decellularized Porcine Whole-Ovary Scaffold with a Preserved Microarchitecture

The application of decellularized scaffolds for artificial tissue reconstruction has been an approach with great therapeutic potential in regenerative medicine. Recently, biomimetic ovarian tissue reconstruction was proposed to reestablish ovarian endocrine functions. Despite many decellularization methods proposed, there is no established protocol for whole ovaries by detergent perfusion that is able to preserve tissue macro and microstructure with higher efficiency. This generated biomaterial may have the potential to be applied for other purposes beyond reproduction and be translated to other areas in the tissue engineering field. Therefore, this study aimed to establish and standardize a protocol for porcine ovaries' decellularization based on detergent perfusion and ultrasonication to obtain functional whole-ovary scaffolds. For that, porcine ovaries (n = 5) were perfused with detergents (0.5% SDS and 1% Triton X-100) and submitted to an ultrasonication bath to produce acellular scaffolds. The decellularization efficiency was evaluated by DAPI staining and total genomic DNA quantification. ECM morphological evaluation was performed by histological, immunohistochemistry, and ultrastructural analyses. ECM physico-chemical composition was evaluated using FTIR and Raman spectroscopy. A cytocompatibility and cell adhesion assay using murine fibroblasts was performed. Results showed that the proposed method was able to remove cellular components efficiently. There was no significant ECM component loss in relation to native tissue, and the scaffolds were cytocompatible and allowed cell attachment. In conclusion, the proposed decellularization protocol produced whole-ovaries scaffolds with preserved ECM composition and great potential for application in tissue engineering.

"Lights and Shades" of Fertility Preservation in Transgender Men Patients: A Clinical and Pathological Review

Fertility preservation (FP) is becoming a critical issue in transgender men who desire biological offspring in the future. The prevalence of transgender individuals in the United States is increasing, and as a result, the demand for gender-affirming surgeries (GAS) and associated FP techniques is rising. Despite the growing demand, there is currently no personalized approach to FP for transgender men, and the available techniques have limitations that require further investigation. In the present review we carefully examine the existing literature on this topic to highlight the shortcomings of current methods and areas where additional research is needed to advance the field. Hormonal therapy (HT), which is an integral part of gender transition in transgender men, can have a significant impact on fertility and may increase the risk of various diseases. Moreover, GAS usually leads to permanent sterility in these patients. Therefore, it is essential to provide patients with accurate information about the benefits and potential risks of different FP techniques, taking into account the patient's reproductive goals. This review underscores the complex and multifaceted nature of FP in transgender men and emphasizes the need for further research to develop more effective and personalized approaches to FP for this population.

Current Trends on Bioengineering Approaches for Ovarian Microenvironment Reconstruction

Ovarian tissue has a unique microarchitecture and a complex cellular and molecular dynamics that are essential for follicular survival and development. Due to this great complexity, several factors may lead to ovarian insufficiency, and therefore to systemic metabolic disorders and female infertility. Techniques currently used in the reproductive clinic such as oocyte cryopreservation or even ovarian tissue transplant, although effective, have several limitations, which impair their wide application. In this scenario, mimetic ovarian tissue reconstruction comes as an innovative alternative to develop new methodologies for germ cells preservation and ovarian functions restoration. The ovarian extracellular matrix (ECM) is crucial for oocyte viability maintenance, once it acts actively in folliculogenesis. One of the key components of ovarian bioengineering is biomaterials application that mimics ECM and provides conditions for cell anchorage, proliferation, and differentiation. Therefore, this review aims at describing ovarian tissue engineering approaches and listing the main limitations of current methods for preservation and reestablishment of ovarian fertility. In addition, we describe the main elements that structure this study field, highlighting the main advances and the challenges to overcome to develop innovative methodologies to be applied in reproductive medicine. Impact Statement This review presents the main advances in the application of tissue bioengineering in the ovarian tissue reconstruction to develop innovative solutions for ovarian fertility reestablishment.

Vitrification versus slow freezing of human ovarian tissue: a systematic review and meta-analysis of histological outcomes

A systematic review and meta-analysis of pertinent literature published from 2006 to January 2022 were conducted to study and compare vitrification and slow freezing, the two prominent methods of ovarian tissue cryopreservation. The primary outcome measures for this study were (1) proportion of intact primordial follicles, (2) proportion of intact stromal cells, (3) proportion of DNA fragmentation in primordial follicles, and (4) mean primordial follicle density. This meta-analysis of 19 studies revealed a significantly greater proportion of intact stromal cells in vitrified tissue versus slow-frozen tissue. No significant differences upon pooled analyses were observed between the two cryopreservation methods with respect to the proportion of intact primordial follicles, proportion of DNA fragmentation, or mean primordial follicle density. Due to differences seen in stromal cell viability, vitrification may be a preferred option to preserve histology of tissue. However, more work should be done to compare the two freezing techniques with less heterogeneity caused by patients, samples, and protocols.

SART CORS IVF registry: looking to the past to shape future perspectives

PURPOSE

The SART CORS database is an informative source of IVF clinic-specific linked data that provides cumulative live birth rates from medically assisted reproduction in the United States (US). These data are used to develop best practice guidelines, for research, quality assurance, and post-market surveillance of assisted reproductive technologies. Here, we sought to investigate the key areas of current research focus (higher-order categories), discover gaps or underserved areas of ART research, and examine the potential application and impact of newer ART adjuvants, future data collection, and analysis needs.

METHODS

We conducted a systematic review (PRISMA guidelines) to quantify unique output metrics of the SART CORS database. Included were SART member reporting clinics: full-length publications from 2004 to 2021 and conference abstracts from 2015 to 2021, the two key timepoints when the SART CORS database underwent transformative shifts in data collection.

RESULTS

We found 206 abstracts presented from 2015 to 2021, 189 full-length peer-reviewed publications since 2004, with 654 unique authors listed on these publications. A total of 19 publications have been highly impactful, garnering over 100 citations at the time of writing. Several higher-order categories, such as endometriosis and tubal infertility, have few publications. The conversion of conference abstracts to full-length papers ranged from 15 to 35% from 2015 to 2021.

CONCLUSIONS

A substantial body of literature has been generated by analyzing the SART CORS database. Full-length publications have increased year over year. Some topic areas, such as endometriosis and tubal infertility, may be underrepresented. Conversion of conference abstracts to full-length publications has been low, indicating that more organizational support may be needed to ensure that research is methodologically sound and researchers supported to reach full publication status.