Advances of three-dimensional (3D) culture systems for in vitro spermatogenesis

Collagen-based materials in male genitourinary diseases and tissue regeneration

Male genitourinary dysfunction causes serious physical or mental distress, such as infertility and psychological harm, which leads to impaired quality of life. Current conventional treatments involving drug therapy, surgical repair, and tissue grafting have a limited effect on recovering the function and fertility of the genitourinary organs. To address these limitations, various biomaterials have been explored, with collagen-based materials increasingly gaining attention for reconstructing the male genitourinary system due to their superior biocompatibility, biodegradability, low antigenicity, biomimetic 3D matrix characteristics, hemostatic efficacy, and tissue regeneration capabilities. This review covers the recent biomedical applications of collagen-based materials including treatment of erectile dysfunction, premature ejaculation, penile girth enlargement, prostate cancer, Peyronie's disease, chronic kidney disease, etc. Although there are relatively few clinical trials, the promising results of the existing studies on animal models reveal a bright future for collagen-based materials in the treatment of male genitourinary diseases.

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Application of Additive Manufacturing in Assisted Reproductive Techniques: What Is the Evidence? A Clinical and Technical Systematic Review of the Literature

Background and Objectives: This article investigates the transformative impact of 3D and bio 3D printing technologies in assisted reproductive technology (ART), offering a comprehensive review of their applications in improving reproductive outcomes. Materials and Methods: Following PRISMA guidelines, we conducted a thorough literature search focusing on the intersection of ART and additive manufacturing, resulting in the inclusion of 48 research papers. Results: The study highlights bio 3D printing's potential in revolutionizing female infertility treatments, especially in follicle complex culture and ovary printing. We explore the use of decellularized extracellular matrix (dECM) as bioink, demonstrating its efficacy in replicating the ovarian microenvironment for in vitro maturation of primordial oocytes. Furthermore, advancements in endometrial cavity interventions are discussed, including the application of sustained-release systems for growth factors and stem cell integration for endometrial regeneration, showing promise in addressing conditions like Asherman's syndrome and thin endometrium. We also examine the role of conventional 3D printing in reproductive medicine, including its use in educational simulators, personalized IVF instruments, and microfluidic platforms, enhancing training and precision in reproductive procedures. Conclusions: Our review underscores both 3D printing technologies' contribution to the dynamic landscape of reproductive medicine. They offer innovative solutions for individualized patient care, augmenting success rates in fertility treatments. This research not only presents current achievements but also anticipates future advancements in these domains, promising to expand the horizons for individuals and families seeking assistance in their reproductive journeys.

The Evolutionary Route of in vitro Human Spermatogenesis: What is the Next Destination?

Malfunction in spermatogenesis due to genetic diseases, trauma, congenital disorders or gonadotoxic treatments results in infertility in approximately 7% of males. The behavior of spermatogonial stem cells (SSCs) within three-dimensional, multifactorial, and dynamic microenvironment implicates a niche that serves as a repository for fertility, since can serve as a source of mature and functional male germ cells. Current protocols enable reprogramming of mature somatic cells into induced pluripotent stem cells (iPSCs) and their limited differentiation to SSCs within the range of 0-5%. However, the resulting human iPSC-derived haploid spermatogenic germ cell yield in terms of number and functionality is currently insufficient for transfer to infertility clinic as a therapeutic tool. In this article, we reviewed the evolution of experimental culture platforms and introduced a novel iPSCs-based approach for in vitro spermatogenesis based on a niche perspective bearing cellular, chemical, and physical factors that provide the complex arrangement of testicular seminiferous tubules embedded within a vascularized stroma. We believe that bioengineered organoids supported by smart bio-printed tubules and microfluidic organ-on-a-chip systems offer efficient, precise, personalized platforms for autologous pluripotent stem cell sources to undergo the spermatogenetic cycle, presenting a promising tool for infertile male patients with complete testicular aplasia.

Stem Cells and Infertility: A Review of Clinical Applications and Legal Frameworks

Infertility is a condition defined by the failure to establish a clinical pregnancy after 12 months of regular, unprotected sexual intercourse or due to an impairment of a person's capacity to reproduce either as an individual or with their partner. The authors have set out to succinctly investigate, explore, and assess infertility treatments, harnessing the potential of stem cells to effectively and safely treat infertility; in addition, this paper will present the legal and regulatory complexities at the heart of stem cell research, with an overview of the legislative state of affairs in six major European countries. For couples who cannot benefit from assisted reproductive technologies (ART) to treat their infertility, stem-cells-based approaches have been shown to be a highly promising approach. Nonetheless, lingering ethical and immunological uncertainties require more conclusive findings and data before such treatment avenues can become mainstream and be applied on a large scale. The isolation of human embryonic stem cells (ESCs) is ethically controversial, since their collection involves the destruction of human embryonic tissue. Overall, stem cell research has resulted in important new breakthroughs in the treatment of infertility. The effort to untangle the complex web of ethical and legal issues associated with such therapeutic approaches will have to rely on evidence-based, broadly shared standards, guidelines, and best practices to make sure that the procreative rights of patients can be effectively reconciled with the core values at the heart of medical ethics.