Diagnostic assessment of the developmental potential of human cryopreserved ovarian tissue from multiple patients using xenografting

BACKGROUND: Although ovarian tissue cryopreservation for women at risk of losing ovarian function is offered by many clinics, there is a lack of evidence relating to the developmental potential of the stored tissue and, therefore, its clinical potential. This study was designed to use xenografting of cryopreserved tissue from multiple patients to assess the reproducibility of preservating developmental potential, the variation in developing follicle profile and the relationship between pre-freeze histology and post-thaw development. METHODS: Using previously published methods, cryopreserved ovarian cortex from nine patients was thawed and grafted under the kidney capsules of immunodeficient mice. Development of follicles was assessed after 26 weeks and compared to histology prior to freezing. RESULTS: Multiple growing follicles including antral stages were observed in multiple grafts of tissue from all patients. Metaphase II oocytes (n=9) were observed in follicles in grafts from five patients. There was no relationship between pre-freeze histology and developing follicle profile in xenografts. CONCLUSIONS: The propanediol freezing method used in this study is capable of reproducibly preserving the developmental potential of human ovarian follicles. The developing follicle profile after cryopreservation cannot be accurately predicted from pre-freeze histology. Xenografting provides a powerful tool for assessing the potential of human cryopreserved ovarian tissue.