Chemotherapy, pelvic radiotherapy and ovarian surgery have known gonadotoxic effects that can lead to endocrine dysfunction, cessation of ovarian endocrine activity and early depletion of the ovarian reserve, causing a risk for future fertility problems, even in children. Important determinants of this risk are the patient’s age and ovarian reserve, type of treatment and dose. When the risk of premature ovarian insufficiency is high, fertility preservation strategies must be offered to the patient. Furthermore, fertility preservation may sometimes be needed in conditions other than cancer, such as in non-malignant diseases or in patients seeking fertility preservation for personal reasons. Oocyte and/or embryo vitrification and ovarian tissue cryopreservation are the two methods currently endorsed by the American Society for Reproductive Medicine, yielding encouraging results in terms of pregnancy and live birth rates. The choice of one technique above the other depends mostly on the age and pubertal status of the patient, and personal and medical circumstances. This review focuses on the available fertility preservation techniques, their appropriateness according to patient age and their efficacy in terms of pregnancy and live birth rates.

(1) Background: Ovarian tissue transplantation with adipose tissue-derived stem cells (ASCs) has been shown to enhance graft vascularization and increase follicle survival after a short interval of 7 days. The aim of the present study was to investigate their long-term effects on primordial follicle pool maintenance and follicle development. (2) Methods: A total of 14 severe combined immunodeficient (SCID) mice were grafted with frozen-thawed human ovarian tissue with or without ASCs. Blood was taken monthly in order to quantify the anti-Müllerian hormone (AMH) and estradiol. After 6 months, all the grafts were retrieved and sent for histology and immunolabeling (AMH, AMH receptor II, estrogen receptors α and β, and c-kit/kit ligand). (3) Results: A significant upturn was observed in AMH and estradiol plasma levels 4 months after transplantation in both grafted groups. The primordial follicle pool was better preserved in the ASC group (41.86 ± 28.35) than in the standard transplantation group (9.65 ± 17.6, p < 0.05) compared to non-grafted controls (124.7 ± 140). (4) Conclusions: The use of ASCs prior to ovarian tissue transplantation yielded a larger primordial follicle pool and more physiological follicle distribution after long-term grafting. These findings suggested that ASC use might extend the ovarian tissue lifespan.

The risk of reseeding malignancy harbored in cryopreserved and transplanted ovarian tissue has been a source of concern. This study aimed to determine the potential relationship between frozen–thawed ovarian tissue transplantation and primary cancer recurrence. Three patients with cerebral primitive neuroectodermal tumors (PNET) were included in this study. One woman gave birth to three healthy babies following reimplantation of her cryopreserved ovarian tissue, but subsequently died due to cancer relapse six years after ovarian tissue transplantation. The second subject died from progressive cancer, while the third is still alive and awaiting reimplantation of her ovarian tissue in due course. Frozen ovarian cortex from all three patients was analyzed and xenotransplanted to immunodeficient mice for five months. Main outcomes were the presence of cancer cells in the thawed and xenografted ovarian tissue at histology, immunostaining (expression of neuron-specific enolase and glial fibrillary acidic protein (GFAP)), and reverse-transcription droplet digital polymerase chain reaction (RT-ddPCR) (levels of enolase 2 and GFAP). In conclusion, no malignant cells were detected in ovarian tissue from patients with PNET, even in those who experienced recurrence of the disease, meaning that the risk of reseeding cancer cells with ovarian tissue transplantation in these patients can be considered low.

To investigate whether adipose tissue-derived stem cells (ASCs) modulate hypoxia and oxidative stress in human ovarian tissue transplants. Prospective experimental study SETTING: Gynecological research unit in a university hospital PATIENT(S): Cryopreserved ovarian cortex from 5 adult women. Thirty mice were grafted with frozen-thawed human ovarian tissue, with or without ASCs (2-step/ASCs+ovarian tissue [OT] group and OT group). The ovarian grafts were retrieved on days 3 (n = 5), 10 (n = 5), and 21 (n = 5). The 10 animals grafted for 21 days underwent in vivo evaluations using microdialysis. One piece of ovarian tissue per patient was fixed for analysis after thawing (non-grafted controls). Direct reactive oxygen species were collected every second day after grafting by means of microdialysis. Analyses of ovarian fragments included immunolabeling for double CD34 (revascularization by host and graft components); immunofluorescence for hypoxia-inducible factor 1α (hypoxia-related response), nuclear factor erythroid 2-related factor 2 (oxidative stress-related response), and 8-hydroxy-deoxyguanosine (oxidative stress-related DNA damage); and gene expression (quantitative reverse transcription polymerase chain reaction) for vascular endothelial growth factor-A (neoangiogenesis), superoxide dismutase 2 (antioxidant activity), and nuclear respiratory factor 1 (mitochondrial biogenesis). Reactive oxygen species peaked earlier in the ASC group (day 2) compared with that in the OT group (day 10) after grafting. Total vascularization was stable in the ASC group at all time points, while it was lower in the OT group 3 days after grafting. Hypoxia-inducible factor 1α expression, also detected in non-grafted controls, was significantly lower in the ASC group than in the OT group on days 3 and 10. The increase in VEGF gene expression lasted significantly longer in the ASC group than in the OT group. There was no significant upturn in the oxidative stress-related response (nuclear factor erythroid 2-related factor 2 pathway) or oocyte DNA damage (8-hydroxy-deoxyguanosine) in any of the grafted groups. Use of ASCs allows faster ovarian graft reperfusion and mitigates the hypoxia-related response through rapid revascularization, sustained by prolonged increase in vascular endothelial growth factor after grafting. No evidence of oxidative stress-related damage was detected irrespective of the transplantation strategy.