Ovarian tissue cryopreservation for fertility preservation before hematopoietic stem cell transplantation in patients with sickle cell disease: safety, ovarian function follow-up, and results of ovarian tissue transplantation.

PURPOSE: To describe the experience of performing ovarian tissue cryopreservation (OTC) before hematopoietic stem cell transplantation (HSCT), among girls/women with severe sickle cell disease (SCD)(SS or S/ß0-thalassemia) who are, besides the usual surgical risk, at risk of SCD-related complications during the fertility preservation procedure for improving their counseling and management. METHODS: This retrospective study included 75 patients (girls/women) with SCD who have had OTC before myeloablative conditioning regimen (MAC) for HSCT. Characteristics of patients and data on OTC, ovarian status follow-up, and results of ovarian tissue transplantation (OTT) were collected in medical records. RESULTS: At OTC, the median (IQR 25-75; range) age of the patients was 9.6 (6.9-14.1; 3.6-28.3) years, 56/75 were prepubertal, and no SCD or surgery-related complications occurred. The median follow-up post-HSCT was > 9 years. At the last follow-up, among prepubertal patients at HSCT, 26/56 were ≥ 15 years old and presented with a premature ovarian insufficiency (POI), except 2, including the patient who had received an OTT to induce puberty. Eight were 13-15 years old and presented for POI. The remaining 22 patients were under 13. Among the 19 patients who were menarche at HSCT, 2 died 6 months post-HSCT and we do not have ovarian function follow-up for the other 2 patients. All the remaining patients (n = 15) had POI. Five patients had OTT. All had a return of ovarian function. One patient gave birth to a healthy baby. CONCLUSION: OTC is a safe fertility preservation technique and could be offered before MAC independent of the patient's age.

Impact of Hydroxyurea on follicle density in patients with sickle cell disease.

The impact of hydroxyurea (HU) on the ovarian reserve of female patients with sickle cell disease (SCD) remains poorly elucidated. Only direct histological analysis of ovarian follicle density can effectively evaluate HU's effect on ovarian reserve. By analyzing digitized slides of ovarian tissue from girls and young women with SCD who underwent ovarian tissue cryopreservation (OTC) before hematological stem cell transplantation (HSCT), we meticulously counted follicles and categorized them based on their growth stage. We then calculated the densities of different follicle types and assessed their correlation with patient characteristics, clinical manifestations, and treatments extracted from medical records. Seventy-six SCD patients participated in the study, with a median age at OTC of 10.2 years (interquartile range [IQR] 7.5, 14.6), and 50 (65.8%) were prepubertal. Of these, 35 patients (46.1%) had received HU, with a median daily dosage of 23.0 mg/kg (IQR 20.0, 25.0) and median exposure time of 44 months (IQR 24.0, 54.0). Primordial follicle density was comparable between the HU and non-HU groups (5.8 follicles/mm2 [IQR 1.0, 13.3] versus 4.2 follicles/mm2 [IQR 1.1, 14.4], respectively; P = .95). However, in the HU group, after adjusting for age, the density of growing follicles was marginally lower compared to the non-HU group (P = .09). Notably, other parameters such as vaso-occlusive crisis did not affect follicular density. In conclusion, exposure to hydroxyurea did not demonstrate a reduction in ovarian reserve in girls/women with SCD. Therefore, fertility preservation measures before initiating HU treatment do not seem necessary.

A 20-year overview of fertility preservation in boys: new insights gained through a comprehensive international survey.

STUDY QUESTION: Twenty years after the inception of the first fertility preservation programme for pre-pubertal boys, what are the current international practices with regard to cryopreservation of immature testicular tissue? SUMMARY ANSWER: Worldwide, testicular tissue has been cryopreserved from over 3000 boys under the age of 18 years for a variety of malignant and non-malignant indications; there is variability in practices related to eligibility, clinical assessment, storage, and funding. WHAT IS KNOWN ALREADY: For male patients receiving gonadotoxic treatment prior to puberty, testicular tissue cryopreservation may provide a method of fertility preservation. While this technique remains experimental, an increasing number of centres worldwide are cryopreserving immature testicular tissue and are approaching clinical application of methods to use this stored tissue to restore fertility. As such, standards for quality assurance and clinical care in preserving immature testicular tissue should be established. STUDY DESIGN SIZE DURATION: A detailed survey was sent to 17 centres within the recently established ORCHID-NET consortium, which offer testicular tissue cryopreservation to patients under the age of 18 years. The study encompassed 60 questions and remained open from 1 July to 1 November 2022. PARTICIPANTS/MATERIALS SETTING METHODS: Of the 17 invited centres, 16 completed the survey, with representation from Europe, Australia, and the USA. Collectively, these centres have cryopreserved testicular tissue from patients under the age of 18 years. Data are presented using descriptive analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Since the establishment of the first formal fertility preservation programme for pre-pubertal males in 2002, these 16 centres have cryopreserved tissue from 3118 patients under the age of 18 years, with both malignant (60.4%) and non-malignant (39.6%) diagnoses. All centres perform unilateral biopsies, while 6/16 sometimes perform bilateral biopsies. When cryopreserving tissue, 9/16 centres preserve fragments sized ≤5 mm3 with the remainder preserving fragments sized 6-20 mm3. Dimethylsulphoxide is commonly used as a cryoprotectant, with medium supplements varying across centres. There are variations in funding source, storage duration, and follow-up practice. Research, with consent, is conducted on stored tissue in 13/16 centres. LIMITATIONS REASONS FOR CAUTION: While this is a multi-national study, it will not encompass every centre worldwide that is cryopreserving testicular tissue from males under 18 years of age. As such, it is likely that the actual number of patients is even higher than we report. Whilst the study is likely to reflect global practice overall, it will not provide a complete picture of practices in every centre. WIDER IMPLICATIONS OF THE FINDINGS: Given the research advances, it is reasonable to suggest that cryopreserved immature testicular tissue will in the future be used clinically to restore fertility. The growing number of patients undergoing this procedure necessitates collaboration between centres to better harmonize clinical and research protocols evaluating tissue function and clinical outcomes in these patients. STUDY FUNDING/COMPETING INTERESTS: K.D. is supported by a CRUK grant (C157/A25193). R.T.M. is supported by an UK Research and Innovation (UKRI) Future Leaders Fellowship (MR/S017151/1). The MRC Centre for Reproductive Health at the University of Edinburgh is supported by MRC (MR/N022556/1). C.L.M. is funded by Kika86 and ZonMW TAS 116003002. A.M.M.v.P. is supported by ZonMW TAS 116003002. E.G. was supported by the Research Program of the Research Foundation-Flanders (G.0109.18N), Kom op tegen Kanker, the Strategic Research Program (VUB_SRP89), and the Scientific Fund Willy Gepts. J.-B.S. is supported by the Swedish Childhood Cancer Foundation (TJ2020-0026). The work of NORDFERTIL is supported by the Swedish Childhood Cancer Foundation (PR2019-0123; PR2022-0115), the Swedish Research Council (2018-03094; 2021-02107), and the Birgitta and Carl-Axel Rydbeck's Research Grant for Paediatric Research (2020-00348; 2021-00073; 2022-00317; 2023-00353). C.E is supported by the Health Department of the Basque Government (Grants 2019111068 and 2022111067) and Inocente Inocente Foundation (FII22/001). M.P.R. is funded by a Medical Research Council Centre for Reproductive Health Grant No: MR/N022556/1. A.F. and N.R. received support from a French national research grant PHRC No. 2008/071/HP obtained by the French Institute of Cancer and the French Healthcare Organization. K.E.O. is funded by the University of Pittsburgh Medical Center and the US National Institutes of Health HD100197. V.B-L is supported by the French National Institute of Cancer (Grant Seq21-026). Y.J. is supported by the Royal Children's Hospital Foundation and a Medical Research Future Fund MRFAR000308. E.G., N.N., S.S., C.L.M., A.M.M.v.P., C.E., R.T.M., K.D., M.P.R. are members of COST Action CA20119 (ANDRONET) supported by COST (European Cooperation in Science and Technology). The Danish Child Cancer Foundation is also thanked for financial support (C.Y.A.). The authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.