A 20-year overview of fertility preservation in boys: new insights gained through a comprehensive international survey.

STUDY QUESTION: Twenty years after the inception of the first fertility preservation programme for pre-pubertal boys, what are the current international practices with regard to cryopreservation of immature testicular tissue? SUMMARY ANSWER: Worldwide, testicular tissue has been cryopreserved from over 3000 boys under the age of 18 years for a variety of malignant and non-malignant indications; there is variability in practices related to eligibility, clinical assessment, storage, and funding. WHAT IS KNOWN ALREADY: For male patients receiving gonadotoxic treatment prior to puberty, testicular tissue cryopreservation may provide a method of fertility preservation. While this technique remains experimental, an increasing number of centres worldwide are cryopreserving immature testicular tissue and are approaching clinical application of methods to use this stored tissue to restore fertility. As such, standards for quality assurance and clinical care in preserving immature testicular tissue should be established. STUDY DESIGN SIZE DURATION: A detailed survey was sent to 17 centres within the recently established ORCHID-NET consortium, which offer testicular tissue cryopreservation to patients under the age of 18 years. The study encompassed 60 questions and remained open from 1 July to 1 November 2022. PARTICIPANTS/MATERIALS SETTING METHODS: Of the 17 invited centres, 16 completed the survey, with representation from Europe, Australia, and the USA. Collectively, these centres have cryopreserved testicular tissue from patients under the age of 18 years. Data are presented using descriptive analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Since the establishment of the first formal fertility preservation programme for pre-pubertal males in 2002, these 16 centres have cryopreserved tissue from 3118 patients under the age of 18 years, with both malignant (60.4%) and non-malignant (39.6%) diagnoses. All centres perform unilateral biopsies, while 6/16 sometimes perform bilateral biopsies. When cryopreserving tissue, 9/16 centres preserve fragments sized ≤5 mm3 with the remainder preserving fragments sized 6-20 mm3. Dimethylsulphoxide is commonly used as a cryoprotectant, with medium supplements varying across centres. There are variations in funding source, storage duration, and follow-up practice. Research, with consent, is conducted on stored tissue in 13/16 centres. LIMITATIONS REASONS FOR CAUTION: While this is a multi-national study, it will not encompass every centre worldwide that is cryopreserving testicular tissue from males under 18 years of age. As such, it is likely that the actual number of patients is even higher than we report. Whilst the study is likely to reflect global practice overall, it will not provide a complete picture of practices in every centre. WIDER IMPLICATIONS OF THE FINDINGS: Given the research advances, it is reasonable to suggest that cryopreserved immature testicular tissue will in the future be used clinically to restore fertility. The growing number of patients undergoing this procedure necessitates collaboration between centres to better harmonize clinical and research protocols evaluating tissue function and clinical outcomes in these patients. STUDY FUNDING/COMPETING INTERESTS: K.D. is supported by a CRUK grant (C157/A25193). R.T.M. is supported by an UK Research and Innovation (UKRI) Future Leaders Fellowship (MR/S017151/1). The MRC Centre for Reproductive Health at the University of Edinburgh is supported by MRC (MR/N022556/1). C.L.M. is funded by Kika86 and ZonMW TAS 116003002. A.M.M.v.P. is supported by ZonMW TAS 116003002. E.G. was supported by the Research Program of the Research Foundation-Flanders (G.0109.18N), Kom op tegen Kanker, the Strategic Research Program (VUB_SRP89), and the Scientific Fund Willy Gepts. J.-B.S. is supported by the Swedish Childhood Cancer Foundation (TJ2020-0026). The work of NORDFERTIL is supported by the Swedish Childhood Cancer Foundation (PR2019-0123; PR2022-0115), the Swedish Research Council (2018-03094; 2021-02107), and the Birgitta and Carl-Axel Rydbeck's Research Grant for Paediatric Research (2020-00348; 2021-00073; 2022-00317; 2023-00353). C.E is supported by the Health Department of the Basque Government (Grants 2019111068 and 2022111067) and Inocente Inocente Foundation (FII22/001). M.P.R. is funded by a Medical Research Council Centre for Reproductive Health Grant No: MR/N022556/1. A.F. and N.R. received support from a French national research grant PHRC No. 2008/071/HP obtained by the French Institute of Cancer and the French Healthcare Organization. K.E.O. is funded by the University of Pittsburgh Medical Center and the US National Institutes of Health HD100197. V.B-L is supported by the French National Institute of Cancer (Grant Seq21-026). Y.J. is supported by the Royal Children's Hospital Foundation and a Medical Research Future Fund MRFAR000308. E.G., N.N., S.S., C.L.M., A.M.M.v.P., C.E., R.T.M., K.D., M.P.R. are members of COST Action CA20119 (ANDRONET) supported by COST (European Cooperation in Science and Technology). The Danish Child Cancer Foundation is also thanked for financial support (C.Y.A.). The authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.

Human fertilization in vivo and in vitro requires the CatSper channel to initiate sperm hyperactivation.

The infertility of many couples rests on an enigmatic dysfunction of the man's sperm. To gain insight into the underlying pathomechanisms, we assessed the function of the sperm-specific multisubunit CatSper-channel complex in the sperm of almost 2,300 men undergoing a fertility workup, using a simple motility-based test. We identified a group of men with normal semen parameters but defective CatSper function. These men or couples failed to conceive naturally and upon medically assisted reproduction via intrauterine insemination and in vitro fertilization. Intracytoplasmic sperm injection (ICSI) was, ultimately, required to conceive a child. We revealed that the defective CatSper function was caused by variations in CATSPER genes. Moreover, we unveiled that CatSper-deficient human sperm were unable to undergo hyperactive motility and, therefore, failed to penetrate the egg coat. Thus, our study provides the experimental evidence that sperm hyperactivation is required for human fertilization, explaining the infertility of CatSper-deficient men and the need of ICSI for medically assisted reproduction. Finally, our study also revealed that defective CatSper function and ensuing failure to hyperactivate represents the most common cause of unexplained male infertility known thus far and that this sperm channelopathy can readily be diagnosed, enabling future evidence-based treatment of affected couples.

Deep learning predicts therapy-relevant genetics in acute myeloid leukemia from Pappenheim-stained bone marrow smears.

ABSTRACT: The detection of genetic aberrations is crucial for early therapy decisions in acute myeloid leukemia (AML) and recommended for all patients. Because genetic testing is expensive and time consuming, a need remains for cost-effective, fast, and broadly accessible tests to predict these aberrations in this aggressive malignancy. Here, we developed a novel fully automated end-to-end deep learning pipeline to predict genetic aberrations directly from single-cell images from scans of conventionally stained bone marrow smears already on the day of diagnosis. We used this pipeline to compile a multiterabyte data set of >2 000 000 single-cell images from diagnostic samples of 408 patients with AML. These images were then used to train convolutional neural networks for the prediction of various therapy-relevant genetic alterations. Moreover, we created a temporal test cohort data set of >444 000 single-cell images from further 71 patients with AML. We show that the models from our pipeline can significantly predict these subgroups with high areas under the curve of the receiver operating characteristic. Potential genotype-phenotype links were visualized with 2 different strategies. Our pipeline holds the potential to be used as a fast and inexpensive automated tool to screen patients with AML for therapy-relevant genetic aberrations directly from routine, conventionally stained bone marrow smears already on the day of diagnosis. It also creates a foundation to develop similar approaches for other bone marrow disorders in the future.

Frequency, morbidity and equity - the case for increased research on male fertility.

Currently, most men with infertility cannot be given an aetiology, which reflects a lack of knowledge around gamete production and how it is affected by genetics and the environment. A failure to recognize the burden of male infertility and its potential as a biomarker for systemic illness exists. The absence of such knowledge results in patients generally being treated as a uniform group, for whom the strategy is to bypass the causality using medically assisted reproduction (MAR) techniques. In doing so, opportunities to prevent co-morbidity are missed and the burden of MAR is shifted to the woman. To advance understanding of men's reproductive health, longitudinal and multi-national centres for data and sample collection are essential. Such programmes must enable an integrated view of the consequences of genetics, epigenetics and environmental factors on fertility and offspring health. Definition and possible amelioration of the consequences of MAR for conceived children are needed. Inherent in this statement is the necessity to promote fertility restoration and/or use the least invasive MAR strategy available. To achieve this aim, protocols must be rigorously tested and the move towards personalized medicine encouraged. Equally, education of the public, governments and clinicians on the frequency and consequences of infertility is needed. Health options, including male contraceptives, must be expanded, and the opportunities encompassed in such investment understood. The pressing questions related to male reproductive health, spanning the spectrum of andrology are identified in the Expert Recommendation.

Male minipuberty in human and non-human primates: planting the seeds of future fertility.

In brief: Minipuberty is a transient activity period of the hypothalamic-pituitary-gonadal axis in the postnatal and infant period including surging serum concentrations of reproductive hormones. Increasing evidence points to an important role of this period for maturation of the testes and thereby for male reproductive function. Abstract: Minipuberty is a transient activity period of the hypothalamic-pituitary-gonadal (HPG) axis in the postnatal and infant period in humans and non-human primates. Hallmarks of this period are surging serum concentrations of reproductive hormones. While in females, the role of minipuberty seems to be dispensable for future fertility, in males, it is significantly associated with reproductive function in later life. In males, this activity period promotes further masculinization, including testicular and penile growth, as well as completion of testicular descent if not already achieved at birth. At the testicular level, both, somatic and germ cells undergo proliferation and partial maturation during this period. Minipuberty is thought to prime male gonadal tissue for subsequent growth and maturation. Notably, perturbed or absent minipuberty is associated with reduced male reproductive function in adulthood. While the sustained HPG axis activity during adulthood is known to control reproductive function, minipuberty appears to be a prerequisite for obtaining full male reproductive function in later life, thereby determining future fertility potential, i.e. the ability to father a child. This review maps the role of male minipuberty for reproductive function and presents suitable animal models to study minipuberty. Also, it describes the development and maturation of testicular cell types, discusses short- and long-term effects of minipuberty and highlights future research perspectives.

Interplay of spermatogonial subpopulations during initial stages of spermatogenesis in adult primates.

The spermatogonial compartment maintains spermatogenesis throughout the reproductive lifespan. Single-cell RNA sequencing (scRNA-seq) has revealed the presence of several spermatogonial clusters characterized by specific molecular signatures. However, it is unknown whether the presence of such clusters can be confirmed in terms of protein expression and whether protein expression in the subsets overlaps. To investigate this, we analyzed the expression profile of spermatogonial markers during the seminiferous epithelial cycle in cynomolgus monkeys and compared the results with human data. We found that in cynomolgus monkeys, as in humans, undifferentiated spermatogonia are largely quiescent, and the few engaged in the cell cycle were immunoreactive to GFRA1 antibodies. Moreover, we showed that PIWIL4+ spermatogonia, considered the most primitive undifferentiated spermatogonia in scRNA-seq studies, are quiescent in primates. We also described a novel subset of early differentiating spermatogonia, detectable from stage III to stage VII of the seminiferous epithelial cycle, that were transitioning from undifferentiated to differentiating spermatogonia, suggesting that the first generation of differentiating spermatogonia arises early during the epithelial cycle. Our study makes key advances in the current understanding of male germline premeiotic expansion in primates.

Transcriptome analyses in infertile men reveal germ cell-specific expression and splicing patterns.

The process of spermatogenesis-when germ cells differentiate into sperm-is tightly regulated, and misregulation in gene expression is likely to be involved in the physiopathology of male infertility. The testis is one of the most transcriptionally rich tissues; nevertheless, the specific gene expression changes occurring during spermatogenesis are not fully understood. To better understand gene expression during spermatogenesis, we generated germ cell-specific whole transcriptome profiles by systematically comparing testicular transcriptomes from tissues in which spermatogenesis is arrested at successive steps of germ cell differentiation. In these comparisons, we found thousands of differentially expressed genes between successive germ cell types of infertility patients. We demonstrate our analyses' potential to identify novel highly germ cell-specific markers (TSPY4 and LUZP4 for spermatogonia; HMGB4 for round spermatids) and identified putatively misregulated genes in male infertility (RWDD2A, CCDC183, CNNM1, SERF1B). Apart from these, we found thousands of genes showing germ cell-specific isoforms (including SOX15, SPATA4, SYCP3, MKI67). Our approach and dataset can help elucidate genetic and transcriptional causes for male infertility.

New perspectives on fertility in transwomen with regard to spermatogonial stem cells.

Objective: Germ cells of transwomen are affected by gender-affirming hormone therapy (GAHT). Fertility will be lost after surgical intervention; thereby, fertility preservation becomes an increasingly imortant topic. This study investigated if the absolute number of spermatogonia in transwomen is comparable at the time of gender-affirming surgery (GAS) to that in pre-pubertal boys. Methods: We carried out a retrospective study of testicular tissues from 25 selected subjects, which had undergone a comparable sex hormone therapy regimen using cyproterone acetate (10 or 12.5 mg) and estrogens. As controls, testicular biopsies of five cisgender adult men (aged 35-48 years) and five pre-/pubertal boys (5-14 years) were included. Testicular tissues were immunohistochemically stained for MAGE A4-positive cells, the most advanced germ cell type. The number of spermatogonia per area was assessed. Clinical values and serum hormone values for FSH, LH, testosterone, free testosterone, estradiol and prolactin were determined on the day of GAS for correlation analyses. Results: Round spermatids were the most advanced germ cell type in 3 subjects, 5 had an arrest at spermatocyte stage, while 17 showed a spermatogonial arrest. On average, testicular tissues of transwomen contained 25.15 spermatogonia/mm3, a number that was significantly reduced compared to the two control groups (P < 0.01, adult 80.65 spermatogonia/mm3 and pre-/pubertal boys 78.55 spermatogonia/mm3). Linear regression analysis revealed that testes with higher weight and high LH contained more spermatogonia. Conclusion: Irrespective of treatment dose or duration, spermatogenesis was impaired. Spermatogonial numbers were significantly reduced in transwomen compared to the control groups. Lay summary: When transwomen go through treatment to confirm their gender, their germ cells are affected. They lose their fertility after surgery, so fertility preservation becomes an important topic. We carried out a study looking at tissue from testes of 25 people who had been through the same sex hormone therapy until surgery. Blood samples were also taken. As controls, samples were taken from the testes of cisgender boys and adult men. On average, the samples from the testes of transwomen contained a smaller number of early sperm cells compared to the two control groups. Regardless of the dose or length of hormone treatment, the fertility of transwomen was significantly reduced so that counseling about fertility preservation should be offered before hormone therapy.

Sperm characteristics in normal and abnormal ejaculates are differently influenced by the length of ejaculatory abstinence.

BACKGROUND: No association between the length of ejaculatory abstinence (LEA) and semen characteristics has been confirmed. A short LEA has been linked to improved sperm characteristics and a higher pregnancy rate, but its negative influence on sperm chromatin maturity and longevity may adversely affect reproductive outcomes. OBJECTIVES: We sought to determine the influence of LEA on (i) semen parameters in normozoospermic and abnormal ejaculates; and (ii) the outcomes of sperm-preparation methods in a large number of subfertile men undergoing infertility workups. MATERIALS AND METHODS: This retrospective registry-based cohort study analyzed the data of 10,674 ejaculates from 7972 subfertile men, who were then segregated into normozoospermic, oligozoospermic, asthenozoospermic, and oligo-asthenozoospermic cohorts. Variations in semen characteristics and post-wash outcomes were studied between four LEA intervals across 0-15 days. RESULTS: An age-adjusted analysis of covariance (ANCOVA) model linked significant increases in ejaculate volume, sperm concentration (except in the oligozoospermic cohort), and total sperm count to an increased LEA (p < 0.05). LEA was negatively associated with motility (except in the asthenozoospermic cohort) and vitality (p < 0.05). Large-headed spermatozoa were less common with an increased LEA only in the oligo-asthenozoospermic cohort (p < 0.05). In the normozoospermic cohort, a longer LEA led to fewer spermatozoa with amorphous heads but more spermatozoa with tapered heads and cytoplasmic droplets (p < 0.05). LEA extension resulted in greater sperm DNA fragmentation in the abnormal cohort (p < 0.01). The post-wash sperm concentration and total motile sperm count were significantly improved with a longer LEA in the normozoospermic cohort (p < 0.05). DISCUSSION AND CONCLUSION: Considering the findings in this study and existing literature, a generalized recommendation for long LEA has no clinical value. The LEA should be individualized based on the ejaculate profile and the need for specific clinical intervention.

Short-Term Hypothermic Holding of Mouse Immature Testicular Tissue Does Not Alter the Expression of DNA Methyltransferases and Global DNA Methylation Level, Post-Organotypic Culture.

Introduction: Cryopreservation of immature-testicular-tissue (ITT) prior to gonadotoxic treatment, while experimental, is the only recommended option for fertility preservation in prepubertal boys. The handling and manipulation of ITT prior to banking could influence the functionality, genetic and epigenetic integrity of cells. Objectives: To investigate the impact of length of hypothermic holding of mouse ITT on the relative mRNA expression of the DNA methyltransferases (DNMTs) and global DNA methylation, post 14-days of organotypic culture. Methods: ITT from 6-day old mice were handled at hypothermic temperature (4 °C) for 6 and 24 h prior to 14-days organotypic culture. Relative mRNA expression of Dnmt1, Dnmt3a, and Dnmt3b along with global DNA methylation was measured from the cultured ITT. Results: No significant variation in the expression of Dnmt1, Dnmt3a, and Dnmt3b was observed in relation to varying holding time periods used. Further, global DNA methylation was comparable between 0, 6 and 24 h holding groups. Conclusions: Short-term holding of ITT at 4 °C does not affect the DNA methylation process post organotypic culture. While fully acknowledging the limitations of this approach in the mouse model, the results we presented in this report will be of significant interest to the field.

GM-CSF perturbs cell identity in mouse pre-implantation embryos.

Growth factors became attractive candidates for medium supplementation to further improve the quality of embryo culture and to mimic in vivo nutrition. Granulocyte macrophage colony-stimulating factor (GM-CSF) is a cytokine influencing the maternal-fetal interface and supporting placental development in mouse and human. It is expressed in epithelial cells of the endometrium under the regulation of estrogens. The factor is already in clinical use and a large clinical trial showed that, if supplemented to an embryo culture medium, it leads to increased survival of embryos, especially in women with previous miscarriages. Animal and cell culture studies on isolated trophectoderm cells support an effect mainly on cellular expansion. Aim of this study was to investigate, if the supplementation of GM-CSF either in a human ART medium or in a mouse optimized medium, leads to a change in cell number and cell lineages in the early pre-implantation mouse embryo. Our data shows that mouse GM-CSF increased total cell numbers with increasing concentrations. This increase of cell number has not been found in embryos cultured in ART media with or without human GM-CSF (hGM-CSF) or in a mouse medium supplemented with different concentrations of hGM-CSF. The changes were caused by a marked difference in TE and primitive endoderm cell numbers but not due to a change in epiblast cell numbers. Additionally, results show an ectopic expression of NANOG among trophectoderm cells in both, human ART media (with and without GM-CSF) and at increasing concentrations in the mouse and the human GM-CSF supplemented media. In conclusion, we could show that GM-CSF has an effect on cell identity in mice, which might probably also occur in the human. Therefore, we would like to rare awareness that the use of supplements without proper research could bare risks for the embryo itself and probably also in the post-implantation phase.

Limited spermatogenic differentiation of testicular tissue from prepubertal marmosets (Callithrix jacchus) in an in vitro organ culture system.

PURPOSE: of the research: To achieve male fertility preservation and restoration, experimental strategies for in vitro germ cell differentiation are required. The effects of two different culture conditions on in vitro maintenance and differentiation of non-human primate germ cells was studied. Three testes from three 6-month-old marmosets were cultured using a gas-liquid interphase system for 12 days. Testicular maturation in pre-culture control and samples cultured in gonadotropin and serum supplemented and non-supplemented culture samples was evaluated using Periodic Acid-Schiff (PAS) and immunohistochemical stainings. PRINCIPLE RESULTS: Gonadotropins and serum-supplemented tissues demonstrate up to meiotic differentiation (BOULE + Pachytene spermatocyte) and advanced localization of germ cells (MAGEA4+). Moreover, complex (with gonadotropin and marmoset monkey serum) conditions induced progression in somatic cell maturation with advanced seminiferous epithelial organization, maintenance of encapsulation of cultured fragments with peritubular-myoid cells, preservation of tubular structural integrity and architecture. MAJOR CONCLUSIONS: We report stimulation-dependent in vitro meiotic transition in non-human primate testes. This model represents a novel ex vivo approach to obtain crucial developmental progression.

Single-cell RNA-seq unravels alterations of the human spermatogonial stem cell compartment in patients with impaired spermatogenesis.

Despite the high incidence of male infertility, only 30% of infertile men receive a causative diagnosis. To explore the regulatory mechanisms governing human germ cell function in normal and impaired spermatogenesis (crypto), we performed single-cell RNA sequencing (>30,000 cells). We find major alterations in the crypto spermatogonial compartment with increased numbers of the most undifferentiated spermatogonia (PIWIL4+). We also observe a transcriptional switch within the spermatogonial compartment driven by increased and prolonged expression of the transcription factor EGR4. Intriguingly, the EGR4-regulated chromatin-associated transcriptional repressor UTF1 is downregulated at transcriptional and protein levels. This is associated with changes in spermatogonial chromatin structure and fewer Adark spermatogonia, characterized by tightly compacted chromatin and serving as reserve stem cells. These findings suggest that crypto patients are disadvantaged, as fewer cells safeguard their germline's genetic integrity. These identified spermatogonial regulators will be highly interesting targets to uncover genetic causes of male infertility.

New Insights Into Extended Steroid Hormone Profiles in Transwomen in a Multi-Center Setting in Germany.

BACKGROUND: Little information is available on steroid hormone profiles in transwomen on the day of gender affirming surgery (GAS) after gender affirming hormone therapy (GAHT). AIM: We compared extended serum steroid hormone profiles of 77 transwomen with 3 different treatment regimens in order to get more insight on how GAHT changes the hormone system. METHODS: Samples were obtained from 3 independent clinics. Individuals in clinic A (n = 13) and B (n = 51) discontinued GAHT 4-6 weeks and 2 weeks before GAS, individuals in clinic C (n = 13) continued treatment. Testicular tissue, blood samples and questionnaires on age, weight, height, and medication use were received from each patient. Steroid hormones were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS), 6 sex hormones were determined by immunofluorometric assays, and ELISA. Spermatogenesis was scored using the Bergman/Kliesch score. OUTCOMES: Participants were not different with regard to age, BMI, treatment duration, and dosage. Feminized blood serum levels with low LH, low FSH and low testosterone, however, were achieved in persons taking GAHT until GAS. Significantly reduced cortisone levels were seen after stopping GAHT before GAS. RESULTS: GAHT had marked effects on the sex-steroid profile in each person. Factor analysis provided a model explaining 78% of the variance and interdependency of sex steroid levels. Stopping treatment was inversely associated with intactness of the corticosteroid-axis with adrenal steroidogenesis as well as it was inversely associated with pituitary-gonadal hormone production. CLINICAL IMPLICATIONS: Transwomen generally did not have elevated cortisone levels but differed significantly depending on and when GAHT was stopped. STRENGTHS & LIMITATIONS: This is the first study examining the steroid hormone profiles of transgender persons on the day of GAS in a multi-center setting. Additional studies (including follow ups before and after GAS and stress questionnaires) will be necessary to assess these conflicting results about the possible psychological impact on persons undergoing GAS to improve care. CONCLUSION: Concerning feminized blood serum levels, continued GAHT seems the better alternative, however stopping treatment 4-6 weeks prior to surgery was associated with reduced cortisone levels. Schneider F, Wistuba J, Holterhus P-M, et al. New Insights Into Extended Steroid Hormone Profiles in Transwomen in a Multi-Center Setting in Germany. J Sex Med 2021;18:1807-1817.

Heading towards a dead end: The role of DND1 in germ line differentiation of human iPSCs.

The DND microRNA-mediated repression inhibitor 1 (DND1) is a conserved RNA binding protein (RBP) that plays important roles in survival and fate maintenance of primordial germ cells (PGCs) and in the development of the male germline in zebrafish and mice. Dead end was shown to be expressed in human pluripotent stem cells (PSCs), PGCs and spermatogonia, but little is known about its specific role concerning pluripotency and human germline development. Here we use CRISPR/Cas mediated knockout and PGC-like cell (PGCLC) differentiation in human iPSCs to determine if DND1 (1) plays a role in maintaining pluripotency and (2) in specification of PGCLCs. We generated several clonal lines carrying biallelic loss of function mutations and analysed their differentiation potential towards PGCLCs and their gene expression on RNA and protein levels via RNA sequencing and mass spectrometry. The generated knockout iPSCs showed no differences in pluripotency gene expression, proliferation, or trilineage differentiation potential, but yielded reduced numbers of PGCLCs as compared with their parental iPSCs. RNAseq analysis of mutated PGCLCs revealed that the overall gene expression remains like non-mutated PGCLCs. However, reduced expression of genes associated with PGC differentiation and maintenance (e.g., NANOS3, PRDM1) was observed. Together, we show that DND1 iPSCs maintain their pluripotency but exhibit a reduced differentiation to PGCLCs. This versatile model will allow further analysis of the specific mechanisms by which DND1 influences PGC differentiation and maintenance.

Serum and intratesticular inhibin B, AMH, and spermatogonial numbers in trans women at gender-confirming surgery: An observational study.

BACKGROUND: Anti-Müllerian hormone and inhibin B are produced by Sertoli cells. Anti-Müllerian hormone secretion indicates an immature Sertoli cell state. Inhibin B serves as a marker of male fertility. Identification of markers reflecting the presence of germ cells is of particular relevance in trans persons undergoing gender-affirming hormone therapy in order to offer individualized fertility preservation methods. OBJECTIVES: Serum and intratesticular inhibin B and anti-Müllerian hormone values were assessed and related to clinical features, laboratory values, and germ cell numbers. MATERIALS AND METHODS: Twenty-two trans women from three clinics were included. As gender-affirming hormone therapy, 10-12.5 mg of cyproterone acetate plus estrogens were administered. Height, weight, age, medication, and treatment duration were inquired by questionnaires. Serum luteinizing hormone, follicle-stimulating hormone, testosterone, and estradiol were measured by immuno-assays. Serum and intratesticular inhibin B and anti-Müllerian hormone were measured by commercially available ELISAs. Spermatogonia were quantified as spermatogonia per cubic millimeter testicular tissue applying a morphometric analysis of two independent testicular cross-sections per individual after MAGEA4 immunostaining. RESULTS: Patients with high inhibin B levels presented with a higher number of spermatogonia (*p < 0.05). Furthermore, mean serum inhibin B was associated with low age (*p < 0.05), low follicle-stimulating hormone (*p < 0.05), and low testosterone (*p < 0.05). Serum anti-Müllerian hormone, however, was not related to spermatogonial numbers. It correlated with high testosterone (*p < 0.05) and high follicle-stimulating hormone (*p < 0.05) only. High intratesticular inhibin B was accompanied by high luteinizing hormone (*p < 0.05), high follicle-stimulating hormone (**p < 0.01), and high testosterone levels (**p < 0.01). Higher the intratesticular anti-Müllerian hormone levels, the longer gender-affirming hormone therapy was administered (*p < 0.05). DISCUSSION AND CONCLUSION: Serum inhibin B levels indicate the presence of spermatogonia, whereas anti-Müllerian hormone seems not to be a reliable marker concerning germ cell abundance.

Simultaneous detection of sperm membrane integrity and DNA fragmentation by flow cytometry: A novel and rapid tool for sperm analysis.

BACKGROUND: Sperm DNA integrity has become one of the most discussed and promising biomarkers for the assessment of male fertility. However, an easy-to-apply method capable of estimating DNA fragmentation in the live fraction of spermatozoa has remained elusive, preventing this parameter from being fully applied in clinical settings. OBJECTIVES: To validate a novel co-staining for the analysis of DNA fragmentation in membrane-intact spermatozoa. MATERIALS AND METHODS: Normozoospermic semen samples were used to validate the co-staining consisting of acridine orange (AO) and LIVE/DEAD™ Fixable Blue Dead Cell Stain (LD), against established methods for the evaluation of cell viability, propidium iodide stain (PI), and DNA fragmentation, the sperm chromatin structure assay (SCSA), to rule out cross-interference. Furthermore, the accuracy of the method was tested by the evaluation of samples prepared with different amounts of membrane and DNA damage (20, 40, 60, 80, and 100%). RESULTS: No significant differences were observed between the co-staining and the established staining procedures (membrane integrity, p = 0.755; DNA fragmentation p = 0.976). Moreover, high R square values were obtained from the analysis of samples of known membrane (R2  = 0.9959) and DNA damage (R2  = 0.9843). The simultaneous assaying of sperm membrane integrity and nuclear DNA fragmentation allowed the analysis of four sperm categories and thereby to assess the proportion of membrane-intact spermatozoa with compromised DNA integrity. DISCUSSION AND CONCLUSION: This new protocol has the potential to provide clinically relevant information about the DNA fragmentation in membrane-intact spermatozoa. Thus, it has the potential of improving the diagnostic of male infertility and enabling a better understanding of sperm dysfunction.

Distribution of semen examination results 2020 - A follow up of data collated for the WHO semen analysis manual 2010.

BACKGROUND: It is now 11 years since publication of the WHO 2010 guidelines for semen assessment values, and it is critical to determine whether they are still valid and/or whether they should be modified. OBJECTIVES: To utilise data published since 2010 and combine these with data used in the 2010 assessment to provide an updated and more comprehensive representation of the fertile man. This may be utilised to present an updated distribution of values for use by WHO in 2021. MATERIALS AND METHODS: Two specific analyses were performed namely, (1) Analysis 1: Examination of published data following publication of WHO 2010 [termed 2010-2020 data]. (2) Analysis 2: Examination of the data used to help formulate the 2010 distribution of values combined with the data from Analysis (1) [termed WHO 2020]. RESULTS: In total, data from more than 3500 subjects, from twelve countries and five continents were analysed. The 5th centile values for concentration, motility and morphology are: 16 × 106 /ml, 30% progressive motility [42% total motility] and 4% normal forms. DISCUSSION: This study presents substantial additional information to establish more comprehensive and globally applicable lower reference values for semen parameters for fertile men although they do not represent distinct limits between fertile and subfertile men. There are still data missing from many countries and, some geographical regions are not represented. Moreover, the number of subjects although significant is still relatively low (<4000). CONCLUSION: These distributions of values now include semen analysis providing a more global representation of the fertile man. Increasing the number of subjects provides robust information that is also more geographically representative.

Impact of Temperature and Time Interval Prior to Immature Testicular-Tissue Organotypic Culture on Cellular Niche.

Cryopreservation of immature-testicular-tissue (ITT) prior to gonadotoxic treatment, while experimental, is the only recommended option for fertility preservation in prepubertal boys. The handling and manipulation of ITT before cryopreservation could influence the functionality of cells during fertility restoration, which this study explored by evaluating cellular niche and quality of mouse ITT subjected to various temperatures and time durations in vitro. ITT from 6-day-old mice were handled at ultraprofound-hypothermic, profound-hypothermic, and mild-warm-ischemic temperatures for varying time periods prior to 14-day organotypic culture. Viability, functionality, synaptonemal complex and chromatin remodeling markers were assessed. Results have shown that cell viability, testosterone level, and in vitro proliferation ability did not change when ITT were held at ultraprofound-hypothermic-temperature up to 24 h, whereas cell viability was significantly reduced (P < 0.01), when held at profound-hypothermic-temperature for 24 h before culture. Further, cell viability and testosterone levels in cultured cells from profound-hypothermic group were comparable to corresponding ultraprofound-hypothermic group but with moderate reduction in postmeiotic cells (P < 0.01). In conclusion, holding ITT at ultraprofound-hypothermic-temperature is most suitable for organotypic culture, whereas short-term exposure at profound-hypothermic-temperature may compromise postmeiotic germ cell yield post in vitro culture. This data, albeit in mouse model, will have immense value in human prepubertal fertility restoration research.