Ovarian tissue cryopreservation has been proven to preserve fertility against gonadotoxic treatments. It has not been clear how this procedure would perform if planned for the purpose of slowing ovarian aging.
The objective of this study was to determine the feasibility of cryopreserving ovarian tissue to extend reproductive life span and delay menopause by auto-transplantation near menopause.
Based on the existing biological data on follicle loss rates, we generated a stochastic model of primordial follicle wastage to determine the years of delay in menopause (denoted by D) by ovarian tissue cryopreservation and transplantation near menopause. Our model accounted for: i) age at ovarian tissue harvest (21-40), ii) the amount of ovarian cortex harvested, iii) transplantation of harvested tissues in single 6BBA 70D2 6E81 1433 DE98 B1A3 6F07 A0C4 7564 F1B6versus multiple procedures (fractionation); and iv) post-transplant follicle survival (40%- conservative vs. 80%-improved vs. 100%-ideal/hypothetical).
Our model predicted that for most women aged <40 years, ovarian tissue cryopreservation and transplantation would result in a significant delay in menopause. The advantage is greater if the follicle loss post-transplant can be minimized. As an example, D for a woman with median ovarian reserve who cryopreserves 25% of her ovarian cortex at age 25 and for whom 40% of follicles survive post transplantation would be approximately 11.8 years but this extends to 15.5 years if the survival is 80%. As another novel finding, spreading the same amount tissue to repetitive transplants significantly extends the benefit. For example, for the same 25-year-old with median ovarian reserve, 25% cortex removal, and 40% follicle survival, fractionating the transplants to 3 or 6 procedures would result in the corresponding D of 23 or 31 years. The same conditions (3 or 6 procedures) would delay menopause as much as by 47 years if post-transplant follicle survival is improved to 80% with modern approaches. An interactive web tool was created to test all variables and feasibility of ovarian tissue freezing and transplantation to delay ovarian aging (here).
Our model predicts that with harvesting at earlier adult ages and better transplant techniques, a significant menopause postponement and, potentially, fertile lifespan extension can be achieved by ovarian tissue cryopreservation and transplantation in healthy women.
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