Iris de Nie

85 HISTOLOGICAL STUDY ON THE INFLUENCE OF PUBERTY SUPPRESSION AND HORMONAL TREATMENT ON DEVELOPING GERM CELLS 6 levels. If puberty suppression is started in Tanner stage 2, full spermatogenesis is usually not present yet and therefore preservation of spermatozoa is not possible. 54 The equipoise of commencing medical treatment to avoid progression of puberty and delaying treatment to enable semen cryopreservation as only option for biological children may be stressful, as puberty is accompanied by irreversible and often unwanted physical changes such as a lowering of the voice and facial hair growth. Severe genital dysphoria may pose another barrier for fertility preservation, since semen cryopreservation requires masturbation which is non-negotiable for some young transgender women. 54 In addition, TESE, the currently available alternative to obtain spermatozoa for cryopreservation requires invasive procedures including surgery and (general) anesthesia. For transgender women, cryopreservation of germ cells harvested from testicular tissue obtained during gGAS may serve as an alternative to keep the option for genetically related offspring open. How these germ cells can be used for procreation depends on their maturation phase. Spermatozoa can directly be used for ART. However, the use of immature germ cells relies on the feasibility of maturation techniques outside the human body, such as in vitro spermatogenesis. Unfortunately, complete in vitro spermatogenesis has only been successfully demonstrated in mouse models and is still unsuccessful in humans. 40 If in vitro spermatogenesis becomes available in the future, cryopreservation of testicular tissue containing spermatogonial stem cells might be a promising option for fertility preservation in those who are otherwise unable to retain the possibility of having genetically related offspring. Currently, limited data is available on the effect of GAHTon testicular histology and themost advanced germ cell type that can be harvested from testicular tissue obtained at time of gGAS. Previous studies conducted on this topic showed varying proportions of hyalinization of seminiferous tubules as well as conflicting results regarding spermatogenesis, ranging from a complete absence of germ cells to full spermatogenesis. 29,104 Moreover, none of these studies focused on people who initiated medical treatment in early puberty. The primary aim of this study is to evaluate the influence of puberty suppression and/or GAHT on exocrine testicular function, by determining the most advanced germ cell type in orchiectomy specimens obtained during gGAS. We aim to compare the outcome between people who started medical treatment as adult ( ≥ 18 years) and those who started as adolescent in early-puberty (Tanner stage 2-3) or late-puberty (Tanner stage 4-5). In addition, we will assess the influence of discontinuation of medical treatment four weeks prior to gGAS in each of these groups, and the association between the duration of hormonal treatment and the possibilities for fertility preservation. Hereby, we will get insights in the options for fertility preservation in orchiectomy specimens obtained during gGAS after having used puberty suppression and/or hormonal treatment.