Sccaa_a_178490 27..48

Maxime Vermeulen Maria-Grazia Giudice Federico Del Vento Christine Wyns 1Gynecology-Andrology Research Unit, Institut de Recherche Expérimentale et Clinique (IREC), Université Catholique de Louvain, Brussels, 1200, Belgium; 2Department of Gynecology-Andrology, Cliniques Universitaires Saint-Luc, Brussels 1200, Belgium Abstract: While improvements made in the field of cancer therapy allow high survival rates, gonadotoxicity of chemoand radiotherapy can lead to infertility in male and female preand postpubertal patients. Clinical options to preserve fertility before starting gonadotoxic therapies by cryopreserving sperm or oocytes for future use with assisted reproductive technology (ART) are now applied worldwide. Cryopreservation of preand postpubertal ovarian tissue containing primordial follicles, though still considered experimental, has already led to the birth of healthy babies after autotransplantation and is performed in an increasing number of centers. For prepubertal boys who do not produce gametes ready for fertilization, cryopreservation of immature testicular tissue (ITT) containing spermatogonial stem cells may be proposed as an experimental strategy with the aim of restoring fertility. Based on achievements in nonhuman primates, autotransplantation of ITT or testicular cell suspensions appears promising to restore fertility of young cancer survivors. So far, whether in twoor three-dimensional culture systems, in vitro maturation of immature male and female gonadal cells or tissue has not demonstrated a capacity to produce safe gametes for ART. Recently, primordial germ cells have been generated from embryonic and induced pluripotent stem cells, but further investigations regarding efficiency and safety are needed. Transplantation of mesenchymal stem cells to improve the vascularization of gonadal tissue grafts, increase the colonization of transplanted cells, and restore the damaged somatic compartment could overcome the current limitations encountered with transplantation.