Subcutaneous ovarian tissue transplantation in nonhuman primates: duration of endocrine function and normalcy of subsequent offspring as demonstrated by reproductive competence, oocyte production, and telomere length

Antifreeze Protein Supplementation During the Warming of Vitrified Bovine Ovarian Tissue Can Improve the Ovarian Tissue Quality After Xenotransplantation

The occurrence of ice crystallization during ovarian tissue (OT) cryopreservation causes unavoidable cryodamage, and ice recrystallization during the warming is more detrimental than ice crystallization. Here, we investigated that antifreeze protein (AFP) treatment during the warming procedure can improve the bovine OT quality after xenotransplantation (XT). Bovine OTs (n=120) were evenly assigned to four groups: fresh, vitrified-warmed, vitrified-warmed with 10 mg/mL Leucosporidium ice-binding protein (LeIBP, a type of AFP) (LeIBP-10), and vitrified-warmed with 20 mg/mL LeIBP (LeiBP-20). LeIBPs were added to the first warming solution. Twenty pieces of OTs were assigned to each category. The remaining 10 OTs from each category were assigned to the XT-Fresh control, XT-Vitrified-warmed control, XT-LeIBP-10, and XT-LeIBP-20 groups, respectively, and xenotransplanted to 9-week-old ovariectomized nude mice for one week. LeIBP treatment during the warming step increased morphological follicle normality and decreased apoptotic follicle ratios after vitrification-warming and XT. The XT-vitrified-warmed control group showed significantly reduced microvessel density and increased fibrosis when compared to that of the XT-fresh group. Microvessel density and fibrosis were recovered in both LeIBP treated groups. There was no significant difference between the LeIBP-10 and LeIBP-20 groups in all outcomes. AFP treatment during the warming procedure can prevent OT damage, and improve ovarian follicle morphology and apoptosis in both the vitrified-warmed bovine OT and its graft. After confirmation in a human study, AFPs can potentially be applied to human OT cryopreservation to reduce cryodamage and improve the OT quality.

Changes in telomere length and senescence markers during human ovarian tissue cryopreservation

Ovarian tissue cryopreservation is considered as a useful option to preserve fertility for cancer patients. This study purposed to evaluate the change of telomere length and senescence markers during human ovarian tissue cryopreservation. Ovarian tissues were obtained from women who underwent benign ovarian surgery in the gynecology research unit of a university hospital with prior consent and IRB approval. DNA was extracted from the ovarian tissues using a DNeasy tissue kit and telomere lengths in the DNA samples were determined by real time PCR before and after cryopreservation. All tissues were stained with hematoxylin–eosin and subjected to immunohistochemistry and TUNEL assays. Other senescence markers, including p53, p16, p21, and phospho-pRb proteins, were evaluated using western blot analysis. Ovarian tissues were collected from ten patients and prepared for slow freezing with the same size of diameter 4 mm and 1 mm thickness. Mean age of patients was 26.7 ± 6.2 years (range, 16–34 years), and ovarian tissues were cryopreserved and thawed 4 weeks after cryopreservation. The mean telomere length was significantly decreased after cryopreservation (9.57 ± 1.47 bp vs. 8.34 ± 1.83 bp, p = 0.001). Western blot analysis revealed that p53, p16, and p21 proteins increased and phospho-pRb protein expression decreased after ovarian tissue cryopreservation. Ovarian tissue cryopreservation and transplantation is regarded as one of promising options for fertility preservation. However, clinicians and researchers should be aware of possible irreversible DNA changes such as shortening of telomere length and alterations of other senescence markers in human ovarian tissues.

Heterotopic transplantation of cryopreserved ovarian tissue in cancer patients: a case series

Transplantation of cryopreserved ovarian tissue offers patients a chance to preserve fertility during cancer treatment. In this study of ten young women with gynecological cancer, heterotopic sites were tested for serum hormones and follicle growth to estimate transplant longevity and prospects for assisted conception. Frozen-thawed grafts were implanted subcutaneously in the forearm (FA) (2 cases), the abdominal wall (AW) (11 cases), and the peritoneal lining (P) (3 cases) . In the follow-up of 36 months, a total of 80 ovarian cycles in different heterotopic sites were analyzed. FA and AW grafts had wildly fluctuating FSH, while estradiol (E2) reached preovulatory levels only in AW and P grafts. Follicular growth was active in P sites (1.2 ± 0.1 mm/d) and sluggish in FA and AW sites (0.4 ± 0.1 mm/d). A mature oocyte was only retrieved from the AW, while seven other aspirations were unsuccessful. Meanwhile, a patient delivered twice after treatment for Hodgkin's lymphoma when orthotopic transplantation was performed, first from an IVF cycle and subsequently from a natural cycle. In conclusion, these findings offer no strong encouragement for fertility preservation by transplanting cryopreserved ovarian tissue to subcutaneous sites, and although the peritoneal site gave better results, graft longevity averaged the same at around 3 years.