Evaluating testicular tissue for future autotransplantation: focus on cancer cell contamination and presence of spermatogonia in tissue cryobanked for boys diagnosed with a hematological malignancy.

STUDY QUESTION: What is the contamination rate by cancer cells and spermatogonia numbers in immature testicular tissue (ITT) harvested before the start of gonadotoxic therapy in boys with a hematological malignancy? SUMMARY ANSWER: Among our cohort of boys diagnosed with acute lymphoblastic leukemia (ALL) and lymphomas, 39% (n = 11/28) had cancer cells identified in their tissues at the time of diagnosis and all patients appeared to have reduced spermatogonia numbers compared to healthy reference cohorts. WHAT IS KNOWN ALREADY: Young boys affected by a hematological cancer are at risk of contamination of their testes by cancer cells but histological examination is unable to detect the presence of only a few cancer cells, which would preclude autotransplantation of cryobanked ITT for fertility restoration, and more sensitive detection techniques are thus required. Reduced numbers of spermatogonia in ITT in hematological cancer patients have been suggested based on results in a limited number of patients. STUDY DESIGN, SIZE, DURATION: This retrospective cohort study included 54 pre- and peri-pubertal boys who were diagnosed with a hematological malignancy and who underwent a testicular biopsy for fertility preservation at the time of diagnosis before any gonadotoxic therapy between 2005 and 2021. PARTICIPANTS/MATERIALS, SETTING, METHODS: Among the 54 patients eligible in our database, formalin-fixed paraffin-embedded (FFPE) testicular tissue was available for 28 boys diagnosed either with ALL (n = 14) or lymphoma (n = 14) and was used to evaluate malignant cell contamination. Hematoxylin and eosin (H&E) staining was performed for each patient to search for cancer cells in the tissue. Markers specific to each patient's disease were identified at the time of diagnosis on the biopsy of the primary tumor or bone marrow aspiration and an immunohistochemistry (IHC) was performed on the FFPE ITT for each patient to evidence his disease markers. PCR analyses on the FFPE tissue were also conducted when a specific gene rearrangement was available. MAIN RESULTS AND THE ROLE OF CHANCE: The mean age at diagnosis and ITT biopsy of the 28 boys was 7.5 years (age range: 19 months-16 years old). Examination of ITT of the 28 boys on H&E stained sections did not detect malignant cells. Using IHC, we found contamination by cancerous cells using markers specific to the patient's disease in 10 of 28 boys, with a higher rate in patients diagnosed with ALL (57%, n = 8/14) compared with lymphoma (14%, n = 2/14) (P-value < 0.05). PCR showed contamination in three of 15 patients who had specific rearrangements identified on their bone marrow at the time of diagnosis; one of these patients had negative results from the IHC. Compared to age-related reference values of the number of spermatogonia per ST (seminiferous tubule) (Spg/ST) throughout prepuberty of healthy patients from a simulated control cohort, mean spermatogonial numbers appeared to be decreased in all age groups (0-4 years: 1.49 ± 0.54, 4-7 years: 1.08 ± 0.43, 7-11 years: 1.56 ± 0.65, 11-14 years: 3.37, 14-16 years: 5.44 ± 3.14). However, using a cohort independent method based on the Z-score, a decrease in spermatogonia numbers was not confirmed. LIMITATIONS, REASONS FOR CAUTION: The results obtained from the biopsy fragments that were evaluated for contamination by cancer cells may not be representative of the entire cryostored ITT and tumor foci may still be present outside of the biopsy range. WIDER IMPLICATIONS OF THE FINDINGS: ITT from boys diagnosed with a hematological malignancy could bear the risk for cancer cell reseeding in case of autotransplantation of the tissue. Such a high level of cancer cell contamination opens the debate of harvesting the tissue after one or two rounds of chemotherapy. However, as the safety of germ cells can be compromised by gonadotoxic treatments, this strategy warrants for the development of adapted fertility restoration protocols. Finally, the impact of the hematological cancer on spermatogonia numbers should be further explored. STUDY FUNDING/COMPETING INTEREST(S): The project was funded by a grant from the FNRS-Télévie (grant n°. 7.4533.20) and Fondation Contre le Cancer/Foundation Against Cancer (2020-121) for the research project on fertility restoration with testicular tissue from hemato-oncological boys. The authors declare that they have no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Mapping the Development of Human Spermatogenesis Using Transcriptomics-Based Data: A Scoping Review.

In vitro maturation (IVM) is a promising fertility restoration strategy for patients with nonobstructive azoospermia or for prepubertal boys to obtain fertilizing-competent spermatozoa. However, in vitro spermatogenesis is still not achieved with human immature testicular tissue. Knowledge of various human testicular transcriptional profiles from different developmental periods helps us to better understand the testis development. This scoping review aims to describe the testis development and maturation from the fetal period towards adulthood and to find information to optimize IVM. Research papers related to native and in vitro cultured human testicular cells and single-cell RNA-sequencing (scRNA-seq) were identified and critically reviewed. Special focus was given to gene ontology terms to facilitate the interpretation of the biological function of related genes. The different consecutive maturation states of both the germ and somatic cell lineages were described. ScRNA-seq regularly showed major modifications around 11 years of age to eventually reach the adult state. Different spermatogonial stem cell (SSC) substates were described and scRNA-seq analyses are in favor of a paradigm shift, as the Adark and Apale spermatogonia populations could not distinctly be identified among the different SSC states. Data on the somatic cell lineage are limited, especially for Sertoli cells due technical issues related to cell size. During cell culture, scRNA-seq data showed that undifferentiated SSCs were favored in the presence of an AKT-signaling pathway inhibitor. The involvement of the oxidative phosphorylation pathway depended on the maturational state of the cells. Commonly identified cell signaling pathways during the testis development and maturation highlight factors that can be essential during specific maturation stages in IVM.

Cancer cell contamination and decontamination methods for ovaries and testes: special focus on prepubertal gonads with a view to safe fertility restoration.

Fertility restoration in patients that survived a hematological cancer during childhood is a core part of their care pathway. Nonetheless, there might be a risk of contamination of the gonads by cancer cells, especially in patients presenting with leukemia and lymphoma. When only a few cancer cells have reached the gonad, they may not be detected by routine histological examination, and therefore more sensitive techniques are required before being confident of the safety of transplanting cryostored testicular and ovarian tissues or cells back to the patient after recovery. Furthermore, if neoplastic cells are identified in the gonadal tissue, methods to eliminate such cells are urgently awaited as the presence of only a few cancer cells may induce disease relapse in these patients. In this review, contamination rates of human gonadal tissue in the case of leukemia or lymphoma as well as decontamination methods applied to both adult and prepubertal testicular and ovarian tissues are presented. Prepubertal gonads will be the main focus as we aim to show how far we have come in establishing safe approaches to fertility restoration. Advances have been made using animal tissue that is usually artificially contaminated by the addition of cancer cell lines to the gonadal cells or tissue, but these techniques need to be improved and still await development in the case of in vivo cancer cell invasion of tissue.

ART in Europe, 2019: results generated from European registries by ESHRE†.

STUDY QUESTION: What are the data and trends on ART and IUI cycle numbers and their outcomes, and on fertility preservation (FP) interventions, reported in 2019 as compared to previous years? SUMMARY ANSWER: The 23rd ESHRE report highlights the rising ART treatment cycles and children born, alongside a decline in twin deliveries owing to decreasing multiple embryo transfers; fresh IVF or ICSI cycles exhibited higher delivery rates, whereas frozen embryo transfers (FET) showed higher pregnancy rates (PRs), and reported IUI cycles decreased while maintaining stable outcomes. WHAT IS KNOWN ALREADY: ART aggregated data generated by national registries, clinics, or professional societies have been gathered and analyzed by the European IVF-Monitoring (EIM) Consortium since 1997 and reported in a total of 22 manuscripts published in Human Reproduction and Human Reproduction Open. STUDY DESIGN, SIZE, DURATION: Data on medically assisted reproduction (MAR) from European countries are collected by EIM for ESHRE each year. The data on treatment cycles performed between 1 January and 31 December 2019 were provided by either national registries or registries based on initiatives of medical associations and scientific organizations or committed persons in one of the 44 countries that are members of the EIM Consortium. PARTICIPANTS/MATERIALS, SETTING, METHODS: Overall, 1487 clinics offering ART services in 40 countries reported, for the second time, a total of more than 1 million (1 077 813) treatment cycles, including 160 782 with IVF, 427 980 with ICSI, 335 744 with FET, 64 089 with preimplantation genetic testing (PGT), 82 373 with egg donation (ED), 546 with IVM of oocytes, and 6299 cycles with frozen oocyte replacement (FOR). A total of 1169 institutions reported data on IUI cycles using either husband/partner's semen (IUI-H; n = 147 711) or donor semen (IUI-D; n = 51 651) in 33 and 24 countries, respectively. Eighteen countries reported 24 139 interventions in pre- and post-pubertal patients for FP, including oocyte, ovarian tissue, semen, and testicular tissue banking. MAIN RESULTS AND THE ROLE OF CHANCE: In 21 countries (21 in 2018) in which all ART clinics reported to the registry 476 760 treatment cycles were registered for a total population of approximately 300 million inhabitants, allowing the best estimate of a mean of 1581 cycles performed per million inhabitants (range: 437-3621). Among the reporting countries, for IVF the clinical PRs per aspiration slightly decreased while they remained similar per transfer compared to 2018 (21.8% and 34.6% versus 25.5% and 34.1%, respectively). In ICSI, the corresponding PRs showed similar trends compared to 2018 (20.2% and 33.5%, versus 22.5% and 32.1%) When freeze-all cycles were not considered for the calculations, the clinical PRs per aspiration were 28.5% (28.8% in 2018) and 26.2% (27.3% in 2018) for IVF and ICSI, respectively. After FET with embryos originating from own eggs, the PR per thawing was at 35.1% (versus 33.4% in 2018), and with embryos originating from donated eggs at 43.0% (41.8% in 2018). After ED, the PR per fresh embryo transfer was 50.5% (49.6% in 2018) and per FOR 44.8% (44.9% in 2018). In IVF and ICSI together, the trend toward the transfer of fewer embryos continues with the transfer of 1, 2, 3, and ≥4 embryos in 55.4%, 39.9%, 2.6%, and 0.2% of all treatments, respectively (corresponding to 50.7%, 45.1%, 3.9%, and 0.3% in 2018). This resulted in a reduced proportion of twin delivery rates (DRs) of 11.9% (12.4% in 2018) and a similar triplet DR of 0.3%. Treatments with FET in 2019 resulted in twin and triplet DR of 8.9% and 0.1%, respectively (versus 9.4% and 0.1% in 2018). After IUI, the DRs remained similar at 8.7% after IUI-H (8.8% in 2018) and at 12.1% after IUI-D (12.6% in 2018). Twin and triplet DRs after IUI-H were 8.7% and 0.4% (in 2018: 8.4% and 0.3%) and 6.2% and 0.2% after IUI-D (in 2018: 6.4% and 0.2%), respectively. Eighteen countries (16 in 2018) provided data on FP in a total number of 24 139 interventions (20 994 in 2018). Cryopreservation of ejaculated sperm (n = 11 592 versus n = 10 503 in 2018) and cryopreservation of oocytes (n = 10 784 versus n = 9123 in 2018) were most frequently reported. LIMITATIONS, REASONS FOR CAUTION: Caution with the interpretation of results should remain as data collection systems and completeness of reporting vary among European countries. Some countries were unable to deliver data about the number of initiated cycles and/or deliveries. WIDER IMPLICATIONS OF THE FINDINGS: The 23rd ESHRE data collection on ART, IUI, and FP interventions shows a continuous increase of reported treatment numbers and MAR-derived livebirths in Europe. Although it is the largest data collection on MAR in Europe, further efforts toward optimization of both the collection and the reporting, from the perspective of improving surveillance and vigilance in the field of reproductive medicine, are awaited. STUDY FUNDING/COMPETING INTEREST(S): The study has received no external funding and all costs are covered by ESHRE. There are no competing interests.

The time has come for harmonized international ART registration.

For more than two decades, the European IVF-Monitoring Consortium has collected data on IVF in Europe with the aim of monitoring the quality and safety of assisted reproductive technology (ART) treatments, to ensure the highest performance with the lowest risk for patients and their offspring. Likewise, the Society for Assisted Reproductive Technology in the USA and the Australia/New Zealand Assisted Reproduction Database collect, process and publish data in their regions. The better the legal framework for ART surveillance, the more complete and reliable are the datasets. Worldwide, the landscape of ART regulation is fragmented, and until there is a legal obligation to report ART data in all countries, with an appropriate quality control of the data collected, the reported outcomes should be interpreted with caution. Once uniform and harmonized data are achieved, consensus reports based on collective findings can begin to address key topics such as cycle segmentation and complications. Improved registration systems and datasets allowing optimized surveillance should be developed in collaboration with patient representatives to consider patients' needs, especially aiming to provide higher transparency around ART services. Support from national and international reproductive medicine societies will also be essential to the future evolution of ART registries.

Multicentre study on rates and reasons for treatment discontinuation in patients with remaining cryopreserved embryos.

RESEARCH QUESTION: What is the discontinuation rate among patients with remaining cryopreserved embryos in Belgium and what are the reasons for discontinuation? DESIGN: Multicentre, cross-sectional study across 11 Belgian fertility clinics. Patients were eligible (n = 1917) if they had previously undergone an unsuccessful fresh embryo transfer (fresh group) or frozen embryo transfer (FET) (in-between group) and did not start a subsequent FET cycle within 1 year despite having remaining cryopreserved embryos. The denominator was all patients with embryos cryopreserved during the same period (2012-2017) (n = 21,329). Data were collected through an online anonymous questionnaire. RESULTS: The discontinuation rate for patients with remaining cryopreserved embryos was 9% (1917/21329). For the final analysis, 304 completed questionnaires were included. The most important reasons for discontinuing FET cycles were psychological (50%) and physical (43%) burden, effect on work (29%), woman's age (25%) and effect on the relationship (25%). In 69% of cases, the patient themselves made the decision to delay FET treatment. In 16% of respondents, the decision to delay FET was determined by external factors: treating physician (9%), social environment (4%), close family (3%) and society (3%). Suggested improvements were psychological support before (41%), during (51%) and after (51%) treatment, as well as lifestyle counselling (44%) and receiving digital information (43%). CONCLUSIONS: The discontinuation rate is remarkably high in patients with remaining cryopreserved embryos who have a good prognosis. Respondents stressed the need to improve the integration of psychological and patient-tailored care into daily assisted reproductive technology practice.

Optimized Recovery of Immature Germ Cells after Prepubertal Testicular Tissue Digestion and Multi-Step Differential Plating: A Step towards Fertility Restoration with Cancer-Cell-Contaminated Tissue.

Undifferentiated germ cells, including the spermatogonial stem cell subpopulation required for fertility restoration using human immature testicular tissue (ITT), are difficult to recover as they do not easily adhere to plastics. Due to the scarcity of human ITT for research, we used neonatal porcine ITT. Strategies for maximizing germ cell recovery, including a comparison of two enzymatic digestion protocols (P1 and P2) of ITT fragment sizes (4 mm3 and 8 mm3) and multi-step differential plating were explored. Cellular viability and yield, as well as numbers and proportions of DDX4+ germ cells, were assessed before incubating the cell suspensions overnight on uncoated plastics. Adherent cells were processed for immunocytochemistry (ICC) and floating cells were further incubated for three days on Poly-D-Lysine-coated plastics. Germ cell yield and cell types using ICC for SOX9, DDX4, ACTA2 and CYP19A1 were assessed at each step of the multi-step differential plating. Directly after digestion, cell suspensions contained >92% viable cells and 4.51% DDX4+ germ cells. Pooled results for fragment sizes revealed that the majority of DDX4+ cells adhere to uncoated plastics (P1; 82.36% vs. P2; 58.24%). Further incubation on Poly-D-Lysine-coated plastics increased germ cell recovery (4.80 ± 11.32 vs. 1.90 ± 2.07 DDX4+ germ cells/mm2, respectively for P1 and P2). The total proportion of DDX4+ germ cells after the complete multi-step differential plating was 3.12%. These results highlight a reduced proportion and number of germ cells lost when compared to data reported with other methods, suggesting that multi-step differential plating should be considered for optimization of immature germ cell recovery. While Poly-D-Lysine-coating increased the proportions of recovered germ cells by 16.18% (P1) and 28.98% (P2), future studies should now focus on less cell stress-inducing enzymatic digestion protocols to maximize the chances of fertility restoration with low amounts of cryo-banked human ITT.

Organoids as tools to investigate the molecular mechanisms of male infertility and its treatments.

Organoids are 3D structures characterized by cellular spatial organizations and functions close to the native tissue they mimic. Attempts to create organoids originating from several tissues have now been reported, including the testis. Testicular organoids have the potential to improve our knowledge of the mechanisms that regulate testicular morphogenesis, physiology, and pathophysiology. They could especially prove as useful tools to understand the complex mechanisms involved in the regulation of the germ cell niche in infertility cases as they offer the possibility to control and modify the nature of cell types before self-assembly and thereby opening the perspective for developing innovative methods to restore fertility. To date, there are only few studies targeted at testicular organoids' formation and even less describing the generation of organoids with both testis-specific structure and function. While researchers described interesting applications with regards to testicular tissue morphogenesis and drug toxicity, further research is needed before testicular organoids would eventually lead to the generation of fertilizing spermatozoa. This review will present the conventional systems used to induce in vitro maturation of testicular cells, describe the different approaches that have been used for the development of testicular organoids and discuss the potential applications they could have in the field of male reproductive biology.

Evolution of cumulative live birth and dropout rates over six complete IVF/ICSI cycles: a large prospective cohort study.

RESEARCH QUESTION: How do cumulative live birth rates (CLBR), cumulative multiple live birth rates (CMLBR) and dropout rates over six IVF and intracytoplasmic sperm injection (ICSI) cycles change over time? DESIGN: Prospective longitudinal cohort (n = 16,073 patients; 48,946 cycles) starting a first fresh assisted reproductive technology cycle between 1 January 2014 and 31 December 2016, with follow-up until 31 December 2017. Outcomes between the periods 2014-2017 and 2009-2012 were compared. RESULTS: Conservative estimates of CLBR after six complete cycles were significantly higher in women younger than 35 years after every cycle: one to three, adjusted P-value [p adj] < 0.0001; four, p = 0.01; five, p adj = 0.03; six, p adj = 0.04) and after the first cycle in women aged 35-37 years (p adj = 0.04) in 2014-2017 versus 2009-2012. For an optimal estimate, the CLBR was significantly higher after the first three cycles in women younger than 35 years (all p adj < 0.0001) and after the first cycle in women aged 35-37 years (p adj = 0.04). The CMLBR rate decreased from 5.1% ± 0.19 (SE) to 4.1% ± 0.16 for the conservative estimate and from 8.6% ±0.37 (SE) to 6.7% ± 0.30 for the optimal estimate after six complete cycles for the whole cohort. Dropout rates of complete cycles were 26.5% 29.4%, 33.4%, 38.9% and 47.3% after the first to fifth cycle, respectively. Compared with 2009-2012, the dropout rate in the current period was significantly higher for the first (P < 0.0001) and second (P = 0.0124) cycle. CONCLUSION: Over six complete IVF/ICSI cycles, CLBR and dropout rates increased and multiple live birth rates decreased when 2014-2017 was compared with 2009-2012.

Accelerated and Improved Vascular Maturity after Transplantation of Testicular Tissue in Hydrogels Supplemented with VEGF- and PDGF-Loaded Nanoparticles.

Avascular transplantation of frozen-thawed testicular tissue fragments represents a potential future technique for fertility restoration in boys with cancer. A significant loss of spermatogonia was observed in xeno-transplants of human tissue most likely due to the hypoxic period before revascularization. To reduce the effect of hypoxia-reoxygenation injuries, several options have already been explored, like encapsulation in alginate hydrogel and supplementation with nanoparticles delivering a necrosis inhibitor (NECINH) or VEGF. While these approaches improved short-term (5 days) vascular surfaces in grafts, neovessels were not maintained up to 21 days; i.e., the time needed for achieving vessel stabilization. To better support tissue grafts, nanoparticles loaded with VEGF, PDGF and NECINH were developed. Testicular tissue fragments from 4-5-week-old mice were encapsulated in calcium-alginate hydrogels, either non-supplemented (control) or supplemented with drug-loaded nanoparticles (VEGF-nanoparticles; VEGF-nanoparticles + PDGF-nanoparticles; NECINH-nanoparticles; VEGF-nanoparticles + NECINH-nanoparticles; and VEGF-nanoparticles + PDGF-nanoparticles + NECINH-nanoparticles) before auto-transplantation. Grafts were recovered after 5 or 21 days for analyses of tissue integrity (hematoxylin-eosin staining), spermatogonial survival (immuno-histo-chemistry for promyelocytic leukemia zinc finger) and vascularization (immuno-histo-chemistry for α-smooth muscle actin and CD-31). Our results showed that a combination of VEGF and PDGF nanoparticles increased vascular maturity and induced a faster maturation of vascular structures in grafts.

Blood Testis Barrier and Somatic Cells Impairment in a Series of 35 Adult Klinefelter Syndrome Patients.

Klinefelter Syndrome (KS) is the most common genetic cause of infertility in men. Degeneration of the testicular tissue starts in utero and accelerates at puberty with hyalinisation of seminiferous tubules, spermatogonia apoptosis and germ cell maturation arrest. Therefore, fertility preservation in young KS boys has been proposed, although this measure is still debated due to insufficient knowledge of the pathophysiology of the disease. To better understand the underlying mechanisms of testicular failure and germ cell loss, we analysed functional and morphological alterations in the somatic compartment of KS testis, i.e., Sertoli cells, including the blood-testis barrier (BTB) and Leydig cells (LC). We compared three populations: 35 KS 47,XXY non-mosaic patients, 28 Sertoli-cell-only (SCO) syndrome patients and 9 patients with normal spermatogenesis. In KS patients the expression of BTB proteins connexin-43 and claudin-11 assessed with a semi-quantitative scoring system appeared significantly reduced with a disorganised pattern. A significant reduction in seminiferous tubules expressing androgen receptors (AR) was observed in KS compared to normal spermatogenesis controls. INSL3 expression, a marker of LC maturation, was also significantly reduced in KS compared to patients with normal spermatogenesis or SCO. Hence, the somatic compartment impairment in KS could be involved in degeneration of seminiferous tubules.

Significant Benefits of Nanoparticles Containing a Necrosis Inhibitor on Mice Testicular Tissue Autografts Outcomes.

Fertility preservation for prepubertal boys relies exclusively on cryopreservation of immature testicular tissue (ITT) containing spermatogonia as the only cells with reproductive potential. Preclinical studies that used a nude mice model to evaluate the development of human transplanted ITT were characterized by important spermatogonial loss. We hypothesized that the encapsulation of testicular tissue in an alginate matrix supplemented with nanoparticles containing a necrosis inhibitor (NECINH-NPS) would improve tissue integrity and germ cells' survival in grafts. We performed orthotopic autotransplantation of 1 mm³ testicular tissue fragments recovered form mice (aged 4-5 weeks). Fragments were either non-encapsulated, encapsulated in an alginate matrix, or encapsulated in an alginate matrix containing NECINH-NPs. Grafts were recovered 5- and 21-days post-transplantation. We evaluated tissue integrity (hematoxylin-eosin staining), germ cells survival (immunohistochemistry for promyelocytic leukemia zinc-finger, VASA, and protein-boule-like), apoptosis (immunohistochemistry for active-caspase 3), and lipid peroxidation (immunohistochemistry for malondialdehyde). NECINH-NPs significantly improved testicular tissue integrity and germ cells' survival after 21 days. Oxidative stress was reduced after 5 days, regardless of nanoparticle incorporation. No effect on caspase-dependent apoptosis was observed. In conclusion, NECINH-NPs in an alginate matrix significantly improved tissue integrity and germ cells' survival in grafts with the perspective of higher reproductive outcomes.

Generation of Organized Porcine Testicular Organoids in Solubilized Hydrogels from Decellularized Extracellular Matrix.

Cryopreservation of immature testicular tissue (ITT) prior to chemo/radiotherapy is now ethically accepted and is currently the only way to preserve fertility of prepubertal boys about to undergo cancer therapies. So far, three-dimensional culture of testicular cells isolated from prepubertal human testicular tissue was neither efficient nor reproducible to obtain mature spermatozoa, and ITT transplantation is not a safe option when there is a risk of cancer cell contamination of the testis. Hence, generation of testicular organoids (TOs) after cell selection is a novel strategy aimed at restoring fertility in these patients. Here, we created TOs using hydrogels developed from decellularized porcine ITT and compared cell numbers, organization and function to TOs generated in collagen only hydrogel. Organotypic culture of porcine ITT was used as a control. Rheological and mass spectrometry analyses of both hydrogels highlighted differences in terms of extracellular matrix stiffness and composition, respectively. Sertoli cells (SCs) and germ cells (GCs) assembled into seminiferous tubule-like structures delimited by a basement membrane while Leydig cells (LCs) and peritubular cells localized outside. TOs were maintained for 45 days in culture and secreted stem cell factor and testosterone demonstrating functionality of SCs and LCs, respectively. In both TOs GC numbers decreased and SC numbers increased. However, LC numbers decreased significantly in the collagen hydrogel TOs (p < 0.05) suggesting a better preservation of growth factors within TOs developed from decellularized ITT and thus a better potential to restore the reproductive capacity.

Development of a Cytocompatible Scaffold from Pig Immature Testicular Tissue Allowing Human Sertoli Cell Attachment, Proliferation and Functionality.

Cryopreservation of immature testicular tissue before chemo/radiotherapy is the only option to preserve fertility of cancer-affected prepubertal boys. To avoid reintroduction of malignant cells, development of a transplantable scaffold by decellularization of pig immature testicular tissue (ITT) able to support decontaminated testicular cells could be an option for fertility restoration in these patients. We, therefore, compared decellularization protocols to produce a cytocompatible scaffold. Fragments of ITT from 15 piglets were decellularized using three protocols: sodium dodecyl sulfate (SDS)-Triton (ST), Triton-SDS-Triton (TST) and trypsin 0.05%/ethylenediaminetetraacetic acid (EDTA) 0.02%-Triton (TET) with varying detergent concentrations. All protocols were able to lower DNA levels. Collagen retention was demonstrated in all groups except ST 1%, and a significant decrease in glycosaminoglycans was observed in the TST 1% and TET 1% groups. When Sertoli cells (SCs) were cultured with decellularized tissue, no signs of cytotoxicity were detected. A higher SC proliferation rate and greater stem cell factor secretion were observed than with SCs cultured without scaffold. ST 0.01% and TET 3% conditions offered the best compromise in terms of DNA elimination and extracellular matrix (ECM) preservation, while ensuring good attachment, proliferation and functionality of human SCs. This study demonstrates the potential of using decellularized pig ITT for human testicular tissue engineering purposes.

Tissue Engineering to Improve Immature Testicular Tissue and Cell Transplantation Outcomes: One Step Closer to Fertility Restoration for Prepubertal Boys Exposed to Gonadotoxic Treatments.

Despite their important contribution to the cure of both oncological and benign diseases, gonadotoxic therapies present the risk of a severe impairment of fertility. Sperm cryopreservation is not an option to preserve prepubertal boys' reproductive potential, as their seminiferous tubules only contain spermatogonial stem cells (as diploid precursors of spermatozoa). Cryobanking of human immature testicular tissue (ITT) prior to gonadotoxic therapies is an accepted practice. Evaluation of cryopreserved ITT using xenotransplantation in nude mice showed the survival of a limited proportion of spermatogonia and their ability to proliferate and initiate differentiation. However, complete spermatogenesis could not be achieved in the mouse model. Loss of germ cells after ITT grafting points to the need to optimize the transplantation technique. Tissue engineering, a new branch of science that aims at improving cellular environment using scaffolds and molecules administration, might be an approach for further progress. In this review, after summarizing the lessons learned from human prepubertal testicular germ cells or tissue xenotransplantation experiments, we will focus on the benefits that might be gathered using bioengineering techniques to enhance transplantation outcomes by optimizing early tissue graft revascularization, protecting cells from toxic insults linked to ischemic injury and exploring strategies to promote cellular differentiation.

A European perspective on testicular tissue cryopreservation for fertility preservation in prepubertal and adolescent boys.

STUDY QUESTION: What clinical practices, patient management strategies and experimental methods are currently being used to preserve and restore the fertility of prepubertal boys and adolescent males? SUMMARY ANSWER: Based on a review of the clinical literature and research evidence for sperm freezing and testicular tissue cryopreservation, and after consideration of the relevant ethical and legal challenges, an algorithm for the cryopreservation of sperm and testicular tissue is proposed for prepubertal boys and adolescent males at high risk of fertility loss. WHAT IS KNOWN ALREADY: A known late effect of the chemotherapy agents and radiation exposure regimes used to treat childhood cancers and other non-malignant conditions in males is the damage and/or loss of the proliferating spermatogonial stem cells in the testis. Cryopreservation of spermatozoa is the first line treatment for fertility preservation in adolescent males. Where sperm retrieval is impossible, such as in prepubertal boys, or it is unfeasible in adolescents prior to the onset of ablative therapies, alternative experimental treatments such as testicular tissue cryopreservation and the harvesting and banking of isolated spermatogonial stem cells can now be proposed as viable means of preserving fertility. STUDY DESIGN, SIZE, DURATION: Advances in clinical treatments, patient management strategies and the research methods used to preserve sperm and testicular tissue for prepubertal boys and adolescents were reviewed. A snapshot of the up-take of testis cryopreservation as a means to preserve the fertility of young males prior to December 2012 was provided using a questionnaire. PARTICIPANTS/MATERIALS, SETTING, METHODS: A comprehensive literature review was conducted. In addition, survey results of testis freezing practices in young patients were collated from 24 European centres and Israeli University Hospitals. MAIN RESULTS AND THE ROLE OF CHANCE: There is increasing evidence of the use of testicular tissue cryopreservation as a means to preserve the fertility of pre- and peri-pubertal boys of up to 16 year-old. The survey results indicate that of the 14 respondents, half of the centres were actively offering testis tissue cryobanking as a means of safeguarding the future fertility of boys and adolescents as more than 260 young patients (age range less than 1 year old to 16 years of age), had already undergone testicular tissue retrieval and storage for fertility preservation. The remaining centres were considering the implementation of a tissue-based fertility preservation programme for boys undergoing oncological treatments. LIMITATIONS, REASONS FOR CAUTION: The data collected were limited by the scope of the questionnaire, the geographical range of the survey area, and the small number of respondents. WIDER IMPLICATIONS OF THE FINDINGS: The clinical and research questions identified and the ethical and legal issues raised are highly relevant to the multi-disciplinary teams developing treatment strategies to preserve the fertility of prepubertal and adolescent boys who have a high risk of fertility loss due to ablative interventions, trauma or genetic pre-disposition.

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.

Technical Aspects and Clinical Limitations of Sperm DNA Fragmentation Testing in Male Infertility: A Global Survey, Current Guidelines, and Expert Recommendations.

PURPOSE: Sperm DNA fragmentation (SDF) is a functional sperm abnormality that can impact reproductive potential, for which four assays have been described in the recently published sixth edition of the WHO laboratory manual for the examination and processing of human semen. The purpose of this study was to examine the global practices related to the use of SDF assays and investigate the barriers and limitations that clinicians face in incorporating these tests into their practice. MATERIALS AND METHODS: Clinicians managing male infertility were invited to complete an online survey on practices related to SDF diagnostic and treatment approaches. Their responses related to the technical aspects of SDF testing, current professional society guidelines, and the literature were used to generate expert recommendations via the Delphi method. Finally, challenges related to SDF that the clinicians encounter in their daily practice were captured. RESULTS: The survey was completed by 436 reproductive clinicians. Overall, terminal deoxynucleotidyl transferase deoxyuridine triphosphate Nick-End Labeling (TUNEL) is the most commonly used assay chosen by 28.6%, followed by the sperm chromatin structure assay (24.1%), and the sperm chromatin dispersion (19.1%). The choice of the assay was largely influenced by availability (70% of respondents). A threshold of 30% was the most selected cut-off value for elevated SDF by 33.7% of clinicians. Of respondents, 53.6% recommend SDF testing after 3 to 5 days of abstinence. Although 75.3% believe SDF testing can provide an explanation for many unknown causes of infertility, the main limiting factors selected by respondents are a lack of professional society guideline recommendations (62.7%) and an absence of globally accepted references for SDF interpretation (50.3%). CONCLUSIONS: This study represents the largest global survey on the technical aspects of SDF testing as well as the barriers encountered by clinicians. Unified global recommendations regarding clinician implementation and standard laboratory interpretation of SDF testing are crucial.

Global Practice Patterns in the Evaluation of Non-Obstructive Azoospermia: Results of a World-Wide Survey and Expert Recommendations.

PURPOSE: Non-obstructive azoospermia (NOA) represents the persistent absence of sperm in ejaculate without obstruction, stemming from diverse disease processes. This survey explores global practices in NOA diagnosis, comparing them with guidelines and offering expert recommendations. MATERIALS AND METHODS: A 56-item questionnaire survey on NOA diagnosis and management was conducted globally from July to September 2022. This paper focuses on part 1, evaluating NOA diagnosis. Data from 367 participants across 49 countries were analyzed descriptively, with a Delphi process used for expert recommendations. RESULTS: Of 336 eligible responses, most participants were experienced attending physicians (70.93%). To diagnose azoospermia definitively, 81.7% requested two semen samples. Commonly ordered hormone tests included serum follicle-stimulating hormone (FSH) (97.0%), total testosterone (92.9%), and luteinizing hormone (86.9%). Genetic testing was requested by 66.6%, with karyotype analysis (86.2%) and Y chromosome microdeletions (88.3%) prevalent. Diagnostic testicular biopsy, distinguishing obstructive azoospermia (OA) from NOA, was not performed by 45.1%, while 34.6% did it selectively. Differentiation relied on physical examination (76.1%), serum hormone profiles (69.6%), and semen tests (68.1%). Expectations of finding sperm surgically were higher in men with normal FSH, larger testes, and a history of sperm in ejaculate. CONCLUSIONS: This expert survey, encompassing 367 participants from 49 countries, unveils congruence with recommended guidelines in NOA diagnosis. However, noteworthy disparities in practices suggest a need for evidence-based, international consensus guidelines to standardize NOA evaluation, addressing existing gaps in professional recommendations.

Global Practice Patterns and Variations in the Medical and Surgical Management of Non-Obstructive Azoospermia: Results of a World-Wide Survey, Guidelines and Expert Recommendations.

PURPOSE: Non-obstructive azoospermia (NOA) is a common, but complex problem, with multiple therapeutic options and a lack of clear guidelines. Hence, there is considerable controversy and marked variation in the management of NOA. This survey evaluates contemporary global practices related to medical and surgical management for patients with NOA. MATERIALS AND METHODS: A 56-question online survey covering various aspects of the evaluation and management of NOA was sent to specialists around the globe. This paper analyzes the results of the second half of the survey dealing with the management of NOA. Results have been compared to current guidelines, and expert recommendations have been provided using a Delphi process. RESULTS: Participants from 49 countries submitted 336 valid responses. Hormonal therapy for 3 to 6 months was suggested before surgical sperm retrieval (SSR) by 29.6% and 23.6% of participants for normogonadotropic hypogonadism and hypergonadotropic hypogonadism respectively. The SSR rate was reported as 50.0% by 26.0% to 50.0% of participants. Interestingly, 46.0% reported successful SSR in <10% of men with Klinefelter syndrome and 41.3% routinely recommended preimplantation genetic testing. Varicocele repair prior to SSR is recommended by 57.7%. Half of the respondents (57.4%) reported using ultrasound to identify the most vascularized areas in the testis for SSR. One-third proceed directly to microdissection testicular sperm extraction (mTESE) in every case of NOA while others use a staged approach. After a failed conventional TESE, 23.8% wait for 3 months, while 33.1% wait for 6 months before proceeding to mTESE. The cut-off of follicle-stimulating hormone for positive SSR was reported to be 12-19 IU/mL by 22.5% of participants and 20-40 IU/mL by 27.8%, while 31.8% reported no upper limit. CONCLUSIONS: This is the largest survey to date on the real-world medical and surgical management of NOA by reproductive experts. It demonstrates a diverse practice pattern and highlights the need for evidence-based international consensus guidelines.