STUDY QUESTION:Can testicular tissue from trans women (trans tissue) be used to create human testicular organoids? SUMMARY ANSWER:Testosterone-producing and cytotypic human testicular organoids with bicompartmental architecture can be successfully generated from trans tissue. WHAT IS KNOWN ALREADY:Testicular organoids are a promising tool for studying testicular function and the effects of toxicants. Immature testicular cells are currently the most efficient at forming organoids that closely recapitulate seminiferous tubule-like architecture and functions. However, the scarcity of immature human testicular tissue limits its use in high-throughput applications. Conversely, trans tissue is abundantly available and characterized by an immature phenotype. STUDY DESIGN SIZE DURATION:Trans tissue-derived organoids (trans organoids) were histologically and androgenically compared to reference organoids derived from immature (prepubertal and pubertal) and adult cisgender testicular tissues. Additionally, long-term testosterone production and gonadotrophic stimulation were assessed in trans organoids. To evaluate their cytotypic and transcriptomic resemblance to reference testicular tissue stages, trans organoids were compared at the gene expression level to prepubertal, pubertal, and adult cisgender tissues, along with their tissue of origin. PARTICIPANTS/MATERIALS SETTING METHODS:Testicular tissue samples from transgender women, as well as from prepubertal, pubertal, and adult cisgender donors, were used to generate testicular organoids and to compare organoid formation efficiency and testosterone production according to tissue origin. These samples also served as references for transcriptomic comparisons with organoids derived from transgender women's testicular tissue at Day 14 of culture. Testicular organoids were generated and cultured using 3D Petri Dish® platforms. Histochemistry and immunofluorescence staining were employed to characterize cellular composition and spatial organization. Testosterone production in culture media was assessed using electrochemiluminescence immunoassays. RNA was extracted and sequenced from organoids derived from transgender women, as well as from tissue samples of all donor groups. Deconvolution and differential gene expression analyses were performed to compare the organoids with testicular tissues across all groups. MAIN RESULTS AND THE ROLE OF CHANCE:Trans organoids form compartmentalized, cytotypic de novo tissues similar to those from pubertal testicular tissue. Additionally, trans organoids exhibit significant testosterone production, sustain this function over extended culture periods, and respond to gonadotrophic stimulation. Deconvolved bulk RNAseq data indicate that cell population proportions within these organoids are close to those in prepubertal and pubertal testicular tissues. Gene expression clusters trans organoids alongside prepubertal and trans tissues. Functional analysis reveals that trans organoids share with prepubertal, pubertal, and trans tissues varied cellular processes. Factors such as the duration of hormone therapy, the expression of anti-Müllerian hormone-an immaturity marker-within the tubules, and the proportion of peritubular myoid cells in the donor tissue were found to predict the success of trans organoid formation. LARGE SCALE DATA:The bulk RNA-seq raw and preprocessed data are stored under restricted access in the Vrije Universiteit Brussel (VUB) Institutional Data Repository (VUB/IVTD/1/000001) due to participant privacy concerns. Access to the data will be considered by contacting Prof. Yoni Baert (yoni.baert@vub.be). LIMITATIONS REASONS FOR CAUTION:Hormonal data from trans women donors were not acquired in a convenient manner for this study. Deconvolution data allow only cell proportions to be compared, not absolute numbers. WIDER IMPLICATIONS OF THE FINDINGS:This study highlights the potential of trans organoids as a novel and ethically sustainable human-based model for male reproductive health research, reproductive toxicology, and endocrine disruption studies. While trans tissue is a valuable replacement for immature tissue, further research should focus on optimizing organoid architecture, evaluating their utility in reprotoxicity testing, and promoting germ cell differentiation. STUDY FUNDING/COMPETING INTERESTS:This study was conducted with financial support from the VUB Research Council (OZR4004) to S.M.S., the Scientific Research Foundation-Flanders (G026223N) and the Scientific Fund Willy Gepts to Y.B., the Strategic Research Program 89 from the VUB to E.G., and the Mireille Aerens Chair to T.V. The authors declare no conflict of interest.

AndrologyEarly View SOCIETY NEWS Leading at the vanguard of andrology: The Network for Young Researchers in Andrology joins forces with the European Academy of Andrology Alberto de la Iglesia, Corresponding Author Alberto de la Iglesia [email protected] orcid.org/0000-0003-3475-2086 Network for Young Researchers in Andrology (NYRA), Barcelona, Spain Department of Cellular Plasticity and Reproduction, Université Paris Cité, INSERM, CNRS, Institut Cochin, Paris, France Correspondence Alberto de la Iglesia, Network for Young Researchers in Andrology (NYRA), 08021, Barcelona, Spain. Email: [email protected]Search for more papers by this authorDorte L. Egeberg, Dorte L. Egeberg Network for Young Researchers in Andrology (NYRA), Barcelona, Spain European Sperm Bank, Copenhagen, DenmarkSearch for more papers by this authorDaniel Marcu, Daniel Marcu Network for Young Researchers in Andrology (NYRA), Barcelona, Spain School of Biological Science, University of East Anglia, Norwich, UKSearch for more papers by this authorGuillaume Richer, Guillaume Richer orcid.org/0000-0003-2888-9078 Network for Young Researchers in Andrology (NYRA), Barcelona, Spain Genetics, reproduction, and development (GRAD) research group, Biology of the Testis (BITE) laboratory, Vrije Universiteit Brussel, Brussels, BelgiumSearch for more papers by this authorBrendan J. Houston, Brendan J. Houston orcid.org/0000-0002-1078-756X Network for Young Researchers in Andrology (NYRA), Barcelona, Spain School of BioSciences, The University of Melbourne, Parkville, AustraliaSearch for more papers by this authorOmar Ammar, Omar Ammar orcid.org/0000-0001-8048-9747 Network for Young Researchers in Andrology (NYRA), Barcelona, Spain Ar-Razzi Hospital, Ramadi, Iraq Department of Obstetrics and Gynaecology, College of Medicine, University of Anbar, Ramadi, IraqSearch for more papers by this authorGülizar Saritas, Gülizar Saritas Network for Young Researchers in Andrology (NYRA), Barcelona, Spain Department of Growth and Reproduction, Copenhagen University Hospital, Copenhagen, DenmarkSearch for more papers by this authorEmily Delgouffe, Emily Delgouffe Network for Young Researchers in Andrology (NYRA), Barcelona, Spain Genetics, reproduction, and development (GRAD) research group, Biology of the Testis (BITE) laboratory, Vrije Universiteit Brussel, Brussels, BelgiumSearch for more papers by this authorDavor Jezek, Davor Jezek European Academy of Andrology (EAA), Münster, Germany Department for Transfusion Medicine and Transplantation Biology, Reproductive Tissue Bank, University Hospital Zagreb, Zagreb, CroatiaSearch for more papers by this authorCsilla Krausz, Csilla Krausz European Academy of Andrology (EAA), Münster, Germany Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, ItalySearch for more papers by this authorEwa Rajpert-De Meyts, Ewa Rajpert-De Meyts orcid.org/0000-0002-5946-7559 Department of Growth and Reproduction, Copenhagen University Hospital, Copenhagen, Denmark European Academy of Andrology (EAA), Münster, GermanySearch for more papers by this authorHermann M. Behre, Hermann M. Behre European Academy of Andrology (EAA), Münster, Germany Center for Reproductive Medicine and Andrology, University Hospital, Martin Luther University Halle-Wittenberg, Halle, GermanySearch for more papers by this author Alberto de la Iglesia, Corresponding Author Alberto de la Iglesia [email protected] orcid.org/0000-0003-3475-2086 Network for Young Researchers in Andrology (NYRA), Barcelona, Spain Department of Cellular Plasticity and Reproduction, Université Paris Cité, INSERM, CNRS, Institut Cochin, Paris, France Correspondence Alberto de la Iglesia, Network for Young Researchers in Andrology (NYRA), 08021, Barcelona, Spain. Email: [email protected]Search for more papers by this authorDorte L. Egeberg, Dorte L. Egeberg Network for Young Researchers in Andrology (NYRA), Barcelona, Spain European Sperm Bank, Copenhagen, DenmarkSearch for more papers by this authorDaniel Marcu, Daniel Marcu Network for Young Researchers in Andrology (NYRA), Barcelona, Spain School of Biological Science, University of East Anglia, Norwich, UKSearch for more papers by this authorGuillaume Richer, Guillaume Richer orcid.org/0000-0003-2888-9078 Network for Young Researchers in Andrology (NYRA), Barcelona, Spain Genetics, reproduction, and development (GRAD) research group, Biology of the Testis (BITE) laboratory, Vrije Universiteit Brussel, Brussels, BelgiumSearch for more papers by this authorBrendan J. Houston, Brendan J. Houston orcid.org/0000-0002-1078-756X Network for Young Researchers in Andrology (NYRA), Barcelona, Spain School of BioSciences, The University of Melbourne, Parkville, AustraliaSearch for more papers by this authorOmar Ammar, Omar Ammar orcid.org/0000-0001-8048-9747 Network for Young Researchers in Andrology (NYRA), Barcelona, Spain Ar-Razzi Hospital, Ramadi, Iraq Department of Obstetrics and Gynaecology, College of Medicine, University of Anbar, Ramadi, IraqSearch for more papers by this authorGülizar Saritas, Gülizar Saritas Network for Young Researchers in Andrology (NYRA), Barcelona, Spain Department of Growth and Reproduction, Copenhagen University Hospital, Copenhagen, DenmarkSearch for more papers by this authorEmily Delgouffe, Emily Delgouffe Network for Young Researchers in Andrology (NYRA), Barcelona, Spain Genetics, reproduction, and development (GRAD) research group, Biology of the Testis (BITE) laboratory, Vrije Universiteit Brussel, Brussels, BelgiumSearch for more papers by this authorDavor Jezek, Davor Jezek European Academy of Andrology (EAA), Münster, Germany Department for Transfusion Medicine and Transplantation Biology, Reproductive Tissue Bank, University Hospital Zagreb, Zagreb, CroatiaSearch for more papers by this authorCsilla Krausz, Csilla Krausz European Academy of Andrology (EAA), Münster, Germany Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, ItalySearch for more papers by this authorEwa Rajpert-De Meyts, Ewa Rajpert-De Meyts orcid.org/0000-0002-5946-7559 Department of Growth and Reproduction, Copenhagen University Hospital, Copenhagen, Denmark European Academy of Andrology (EAA), Münster, GermanySearch for more papers by this authorHermann M. Behre, Hermann M. Behre European Academy of Andrology (EAA), Münster, Germany Center for Reproductive Medicine and Andrology, University Hospital, Martin Luther University Halle-Wittenberg, Halle, GermanySearch for more papers by this author First published: 20 March 2024 https://doi.org/10.1111/andr.13633Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat CONFLICT OF INTEREST STATEMENT The authors declare no conflict of interest. REFERENCES 1Gromoll J, Michel C, Kostova E, et al. Minutes of the 14th European workshop on molecular and cellular endocrinology of the testis. Mol Cell Endocrinol. 2006; 257-258: 1-5. 10.1016/j.mce.2006.06.001 CASPubMedGoogle Scholar 2Tüttelmann F, de Gendt K, Amaral A, et al. The future of testis research is turning 6! Six years of international network for young researchers in male fertility. Int J Androl. 2012; 35(2): 211-213. 10.1111/j.1365-2605.2012.01251.x PubMedWeb of Science®Google Scholar 3Amaral A, Wahlgren A, Tüttelmann F, et al. Minutes of the 5th meeting of the International Network for Young Researchers in Male Fertility. Asian J Androl. 2012; 14(5): 796. 10.1038/aja.2012.99 PubMedGoogle Scholar 4Marcu D, Egeberg D, Richer G, et al. Shaping the future of male reproductive health: fostering talent at the 14th Network of Young Researchers in Andrology meeting. Biol Open. 2023; 12(5): 5. doi:10.1242/bio.059901 10.1242/bio.059901 Web of Science®Google Scholar 5Marcu D, Egeberg DL, Richer G, et al. 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This study presents a biphasic approach to overcome the limitations of current testicular organoid (TO) cultures, including histological heterogeneity, germ cell loss and absence of spermatogenesis. Agarose microwells were utilized to create TOs from prepubertal C57BL/6 J testicular cells. First emphasis was on improving germ cell survival during the initial 2-week reorganization phase by comparingα-MEM + 10% knockout serum replacement (KSR) medium, known to support TO generation in mice, to three optimized media (1-3). Cell densities and culture dynamics were also tested to recreate histological resemblance to testes. After optimizing germ cell survival and cell organization, the effect of growth factors and immunomodulation through CD45+immune cell depletion or dexamethasone (DEX) supplementation were assessed for enhancing spermatogenesis during the subsequent differentiation phase. Testicular cells self-reorganized into organoids resembling the testicular anatomical unit, characterized by one tubule-like structure surrounded by interstitium. Media 1-3 proved superior for organoid growth during the reorganization phase, with TOs in medium 3 exhibiting germ cell numbers (7.4% ± 4.8%) comparable to controls (9.3% ± 5.3%). Additionally, 37% ± 30% demonstrated organized histology from 32 × 103cells under static conditions. Switching toα-MEM + 10% KSR during the differentiation phase increased formation efficiency to 85 ± 7%, along with elevated germ cell numbers, testosterone production (3.1 ± 0.9 ng ml-1) and generation ofγ-H2AX+spermatid-like cells (steps 8-11, 1.2% ± 2.2% of the total). Adding differentiation factors to theα-MEM increased spermatid-like cell numbers to 2.9% ± 5.9%, confirmed through positive staining for CREM, transition protein 1, and peanut agglutinin. Although, these remained diploid with irregular nuclear maturation. DEX supplementation had no additional effect, and immune cell depletion adversely impacted TO formation. The manipulability of TOs offers advantages in studying male infertility and exploring therapies, with scalability enabling high-throughput chemical screening and reducing animal usage in reproductive toxicity and drug discovery studies.

Testes have a complex architecture that is compartmentalized into seminiferous tubules with a diameter of approximatively 200 μm in which the germ cells differentiate, surrounded by a basement membrane and interstitium. 3D bioprinting might be used to recreate the compartmentalized testicular architecture in vitro. Directed by a software program, pneumatic microextrusion printers can deposit 3D layers of hydrogel-encapsulated interstitial cells in a controlled manner by applying pressure. Once macroporous-shaped scaffolds resembling seminiferous tubules have been bioprinted with interstitial cells, the epithelial cell fraction can be seeded in the macropores to resemble the in vivo testicular architecture. Moreover, macropores can serve as a delimitation for all testicular cells to reorganize and improve the supply of nutrients to cells through the 3D constructs.

The 15th Network of Young Researchers in Andrology (NYRA) meeting, held at the Palace de Caux, Switzerland, served as a valuable platform to disseminate cutting-edge research and facilitate interactions among early-career researchers and trainees in andrology from around the world. Preceding the 22nd European Testis Workshop, the 2-day event brought together participants from a variety of countries to discuss a range of topics pertaining to men's reproductive health and biology. Specific focuses included piRNAs in mammalian reproduction, biomolecules enhancing sperm physiology, advances in in vitro spermatogenesis, reproductive strategies across species, and career development. A dedicated 'scientific speed-dating' social event also stood out, encouraging cross-disciplinary collaborations and strengthening ties within the scientific community. The high participation rate of the meeting highlighted its value in connecting the andrology community. Finally, the announcement of NYRA's merger with the European Academy of Andrology (EAA) marked a pivotal moment, enabling NYRA to support young researchers while collaborating with the EAA to advance andrology research. The 15th NYRA meeting played a crucial role in enhancing knowledge dissemination and andrology research, empowering young researchers, and addressing key challenges in male infertility.

ABSTRACT The 14th Network of Young Researchers in Andrology (NYRA) meeting was a 2-day conference held at the University of East Anglia in Norwich, UK, organized by the NYRA. The meeting brought together researchers and experts to discuss and exchange ideas on male infertility and spermatogenesis. The meeting covered a wide range of topics related to male germline research, including the impact of mutations in the male germline on future generations, the use of innovative sequencing tools for the study of male infertility, and the intricate germline epigenome. The impact of aging on spermatogenesis was also discussed, with a focus on the increased DNA fragmentation rates, changes in DNA methylation patterns, and longer telomeres associated with aging sperm. Additionally, progress on fertility preservation options for children undergoing gonadotoxic cancer treatments was presented. The meeting also featured workshops on leadership and career development strategies in science, providing a valuable opportunity for young researchers to learn from experts in the field and exchange ideas with their peers. Overall, the meeting provided a platform for researchers to discuss the latest developments in male germline research, highlighting the importance of empowering young researchers to tackle male reproductive health.

Abstract Study question Can our newly developed testicular organoid (TO) growth platform advance the robustness of murine TOs? Summary answer The platform resulted in more consistent TO histology. Moreover, improved germ cell survival was observed after a two-week culture with numbers comparable to fresh samples. What is known already Organ cultures have traditionally been used for in-vitro spermatogenesis (IVS) in rodents because they best preserve the testicular architecture which is pivotal in achieving IVS. However, organ cultures do not offer the ability to access and manipulate single cells, making it an inefficient model for mechanistic studies. Organoids made from testicular cell suspensions offer these features. Although TO cultures can result in organoids with compartmentalized testicular architecture, histological heterogeneity between individual TOs limits reproducibility of the results, offering unreliable readouts. Moreover, germ cell loss is characteristic during the reorganization phase. Study design, size, duration Here, we tested a new TO growth platform. Firstly, the focus was put on improving germ cell survival in TOs during tubulogenesis in the first two weeks of culture. For this, four different growth media (A-D), supplemented with other combinations or concentrations of growth factors, were compared. Next, five cell seeding densities (I-V) were tested for their ability to recreate the testicular architecture in TOs in the selected culture media. Participants/materials, setting, methods Testicular cells from 5 days old C57BL/6J mice were grown in our TO platform with alpha-MEM-based medium, previously found to support TO generation in mice (medium A). Three additional conditions were tested in their ability to improve germ cell survival during tubulogenesis (B-D). Finally, the ideal cell density (I-V) was determined based on histological resemblance to native tissue: one tubule-like structure and surrounding interstitium. Cellular reorganization and germ cell maintenance were characterized by (immuno)histochemistry. Main results and the role of chance During short-term cultures of 2 weeks, testicular cells self-assembled and compacted into organoids in our platform. Interestingly, media B and D resulted in the highest amount of germ cells (p < 0.05), comparable to the fresh control. Particularly TOs cultured in medium D also exhibited the largest surface area, indicative for better in-vitro growth. Finally, TOs that were cultured in condition D had the best histology when grown at cell density IV and V (p < 0.05). Limitations, reasons for caution Candidate factors have to be tested in their ability to elevate the meiotic blockage of germ cells typically observed in organ culture, but also in TOs. Finally, results obtained with rodents remain to be confirmed in further human studies. Wider implications of the findings The opportunities TOs offer to manipulate cells (genetic modification, inclusion and exclusion) are essential for the study of male infertility and the search for potential therapies. Moreover, they permit high-throughput screening of chemicals, thereby substantially reducing the number of animals for the high demanding reproductive toxicity and drug discovery studies. Trial registration number not applicable

Chronic exposure to arsenic may cause cancer. Many mechanisms have been suggested for arsenic carcinogenesis. Autophagy, an evolutionarily conserved cellular catabolic mechanism, has been implicated in cancer biology. Although being claimed as a type of cell death, autophagy may actually serve as a cell self-defense mechanism. In this review article, current understandings of the mechanisms of arsenic carcinogenesis, functions of autophagy and the role of autophagy in arsenic carcinogenesis are discussed.

Can improved culture conditions advance the functionality of murine testicular organoids (TOs)? Testicular cells formed spheroidal TOs resembling the functional unit of the testis and supporting meiotic entry of germ cells during long-term culture in printed macropores. Organ cultures at the air-medium interphase have traditionally been used for in-vitro spermatogenesis (IVS) in rodents because they best preserve the testicular architecture, which is pivotal in achieving IVS. However, organ cultures do not offer the ability to access and manipulate single cells, making it an inefficient model for mechanistic studies. Culturing testicular cell suspensions into organoids offer these features. Previously, testicular organoids in immersion culture resulted in testicular architecture, but only supported short-term survival of germ cells. Moreover, millimeter-sized organoids show signs of degeneration due to insufficient nutrient and oxygen supply. First, we focused on recreating the testicular architecture at air-medium interphase and determined whether higher cell densities could improve our previously developed 3D printed culture model during long-term culture using different mouse strains. Afterwards, the focus was put on improving TO morphology by adapting the scaffold design. Moreover, to expand the potential of TOs, the possibility to cultivate chimeric mixtures of testicular cells and germ line stem cells expressing a reporter transgene (EGFP) was assessed. Prepubertal testicular cells from C57BL/6J (n = 5) or CBAB6F1 (n = 3) mice were cultured in the macropores of 3D printed squared 1-layered scaffolds (1LSs) composed of Cellink-RGD (8x104 cells/mm²). Next, 1LS was modified with an additional layer of alginate (2LS) to culture a chimeric mixture of testicular cells of prepubertal C57BL/6J mice and EGFP-expressing germline stem cells (2:1). Cell reorganization and differentiation were characterized by immunohistochemistry and testosterone was quantified by electrochemiluminescence. During long-term cultures in 1LSs, testicular cells reorganized into organoids with restoration of testicular architecture and Leydig cell functionality supporting the differentiation of germ cells to the meiotic phase, regardless of the mouse strain. However, pore overgrowth and fusion of adjacent aggregates, resulted in irregularly shaped TOs. Based on these results, the design of 1LS was modified with an additional layer of alginate to entrap reorganizing cells (2LS). To non-invasively evaluate germ cell behavior, EGFP-expressing germline stem cells were mixed with testicular cells of prepubertal C57BL/6J mice in 2LS. This approach resulted in the formation of chimeric organoids with a more regular and spheroidal morphology. These improved TOs consisted typically of 1 tubule-like structure and surrounding interstitium, representing the functional unit of a testis. in contrast to primary germ cells, germline stem cells were not observed after the 3rd week of culture. Candidate factors have to be tested in their ability to elevate the meiotic blockage of germ cells in TOs. In addition, the culture medium needs further optimization to enhance maintenance of germline stem cells in chimeric models. Finally, results obtained with rodents remain to be confirmed in further human studies. Wider implications of the findings: The opportunities testicular organoids offer to manipulate cells through genetic modification, inclusion and exclusion, are essential for the study of male infertility and the search for potential therapies. Moreover, they permit high-throughput screening of chemicals, thereby substantially reducing the number of animals for the high demanding reproductive toxicity studies. Not applicable

Short-term germ cell survival and central tissue degeneration limit organoid cultures. Here, testicular organoids (TOs) were generated from two different mouse strains in 3D printed one-layer scaffolds (1LS) at the air-medium interface displaying tubule-like structures and Leydig cell functionality supporting long-term survival and differentiation of germ cells to the meiotic phase. Chimeric TOs, consisting of a mixture of primary testicular cells and EGFP+ germline stem (GS) cells, were cultured in two-layer scaffolds (2LSs) for better entrapment. They showed an improved spheroidal morphology consisting of one intact tubule-like structure and surrounding interstitium, representing the functional unit of a testis. However, GS cells did not survive long-term culture. Consequently, further optimization of the culture medium is required to enhance the maintenance and differentiation of germ cells. The opportunities TOs offer to manipulate somatic and germ cells are essential for the study of male infertility and the search for potential therapies.

BACKGROUND:The testicular organoid concept has recently been introduced in tissue engineering to refer to testicular cell organizations modeling testicular architecture and function. The testicular organoid approach gives control over which and how cells reaggregate, which is not possible in organotypic cultures, thereby extending the applicability of in-vitro spermatogenesis (IVS) systems. However, it remains unclear which culture method and medium allow reassociation of testicular cells into a functional testicular surrogate in-vitro.OBJECTIVE:The aim of this paper is to review the different strategies that have been used in an attempt to create testicular organoids and generate spermatozoa. We want to provide an up-to-date list on culture methodologies and media compositions that have been used and determine their role in regulating tubulogenesis and differentiation of testicular cells.SEARCH METHOD:A literature search was conducted in PubMed, Web of Science, and Scopus to select studies reporting the reorganization of testicular cell suspensions in-vitro, using the keywords: three-dimensional culture, in-vitro spermatogenesis, testicular organoid, testicular scaffold, and tubulogenesis. Papers published before the August 1, 2019, were selected.OUTCOME:Only a limited number of studies have concentrated on recreating the testicular architecture in-vitro. While some advances have been made in the testicular organoid research in terms of cellular reorganization, none of the described culture systems is adequate for the reproduction of both the testicular architecture and IVS.CONCLUSION:Further improvements in culture methodology and medium composition have to be made before being able to provide both testicular tubulogenesis and spermatogenesis in-vitro.