Advancements in fertility preservation strategies for pediatric male cancer patients: a review of cryopreservation and transplantation of immature testicular tissue

Abstract

Recently, there has been increasing emphasis on the gonadotoxic effects of cancer therapy in prepubertal boys. As advances in oncology treatments continue to enhance survival rates for prepubertal boys, the need for preserving their functional testicular tissue for future reproduction becomes increasingly vital. Therefore, we explore cutting-edge strategies in fertility preservation, focusing on the cryopreservation and transplantation of immature testicular tissue as a promising avenue. The evolution of cryopreservation techniques, from controlled slow freezing to more recent advancements in vitrification, with an assessment of their strengths and limitations was exhibited. Detailed analysis of cryoprotectants, exposure times, and protocols underscores their impact on immature testicular tissue viability. In transplantation strategy, studies have revealed that the scrotal site may be the preferred location for immature testicular tissue grafting in both autotransplantation and xenotransplantation scenarios. Moreover, the use of biomaterial scaffolds during graft transplantation has shown promise in enhancing graft survival and stimulating spermatogenesis in immature testicular tissue over time. This comprehensive review provides a holistic approach to optimize the preservation strategy of human immature testicular tissue in the future.

Keywords: Cryopreservation; Cryoprotectant; Immature testicular tissue; Scaffold; Slow freezing; Tissue engineering; Vitrification.

Fig. 1

Schematic overview of fertility preservation through cryopreserved, thawed and transplanted ITT. The ITT could be cryopreserved by vitrification or CSF, and then isografted, autografted, or xenografted into species after being thawed. Here were the major milestones in offspring production following these cryopreservation methods. Offspring production was both observed through CSF and vitrification. Researches in this area are currently limited to animal models. LN₂, liquid nitrogen

Fig. 2

Schematic overview of two major scaffolding approaches for tissue engineering. The approaches include tissue fragment encapsulation in hydrogel matrix and premade synthetic porous scaffolds. Additionally, the figure highlights potential outcomes, such as the generation of offspring through ITT transplantation