The effect of high throughput vitrification of human ovarian cortex tissue on follicular viability. A promising alternative to conventional slow freezing ?

Abstract Background: The standard procedure most frequently used for ovarian tissue cryopreservation (OTC) is slow freezing, while vitrification has been proposed as promising alternative and has built an impressive catalogue of success in fertility laboratories regarding cryopreservation of oocytes and embryos. Methods: We developed and evaluated a high throughput protocol for vitrification of human ovarian tissue suitable for clinical processing. Follicular viability was assessed via calcein staining prior and after cryopreservation analysing ovarian tissue of a cohort of 30 patients. Results: We found no significant differences regarding follicular viability between slow frozen and vitrified cortex tissue samples 24 h after thawing and rapid warming. Follicular viability of thawed and rapid warmed samples was not significantly different in comparison to fresh samples, indicating high proportions of follicular survival rates with both methods. Conclusions: High throughput vitrification is a promising option in a clinical setting. More research is needed to determine the status of other tissue specific quality indicators potentially influencing on autotransplantation.