Cryopreservation and in vitro development ability of IVM oocytes from gender identity disorder and cancer patients

Abstract

OBJECTIVE: The purpose of this study was to learn the prospect for normal development of immature oocytes from the ovary. DESIGN: We endeavored to measure the number of normal immature (GV stage) oocytes, the maturation rate, the cryopreservability of the IVM oocytes, and the fertilization and in vitro developmental ability of the in vitro matured vitrified oocytes after ICSI and in vitro culture (IVC). MATERIALS AND METHODS: Oocytes were aspirated from discarded ovaries of patients with reproductive cancer (RC) and gender identity disorder (GID) with informed consent and IRB approval. IVM was performed by using m-199 medium containing 20% SSS for 24 hrs at 37C. IVM oocytes were vitrified by the Cryotop method and post-thaw viability was assessed. After warming, vitrified oocytes were then inseminated by conventional ICSI method. Fertilized oocytes (2PN) were cultured first in cleavage and then in blastocyst media for 5 days. In vitro maturation, fertilization, cleavage (4-8 cells) and blastocyst rates of all groups were examined and compared. RESULTS: A total of 607 oocytes were obtained from 25 RC and 25 GID patients. Post-thaw survival rate of IVM oocytes after vitrification was 85%. In vitro maturation, fertilization, cleavage (4-8 cells) rates of vitrified IVM oocytes from RC and GID patients were 54%, 50%, and 80%, respectively. CONCLUSION: Transferable blastocysts were obtained from GV oocytes of ovaries of RC and GID patients using our present IVM-ICSI-IVC system after cryopreservation by vitrification. The favorable results indicate the possibility of preserving fertility for reproductive cancer patients who lose their ovaries during cancer treatment by using cryopreserved oocytes from ovary, and also indicates the possible use of oocytes from otherwise discarded ovaries of GID women, as precious and useful as experimental material for studying IVM. With ovarian tissue vitrification and IVM, even cancer patients with metastatic ovarian disease could have safe and effective preservation of their fertility.