Towards a universal rapid warming protocol for cryopreserved human ovarian tissue

Area of Science:

• Reproductive Biology
• Cryobiology
• Tissue Engineering

Background:

• Ovarian tissue cryopreservation is crucial for fertility preservation.
• Conventional slow freezing-thawing methods have limitations.
• Rapid-warming protocols, typically used for vitrified tissues, are being explored for slow-frozen tissues.

Purpose of the Study:

• To investigate the feasibility of applying rapid-warming protocols to slow-frozen human ovarian tissue.
• To compare the efficacy of rapid-warming versus conventional thawing methods.
• To determine if a universal warming protocol can be developed for both slow-frozen and vitrified ovarian tissue.

Main Methods:

• Human ovarian tissue samples from 25 patients were cryopreserved using slow freezing.
• Thawing was performed using conventional slow thawing or rapid-warming protocols (in-house or commercial media).
• Follicular viability, anti-Müllerian hormone levels, VEGF-A secretion, apoptosis (TUNEL staining), and primordial follicle preservation were assessed post-thawing and after culture.

Main Results:

• Follicular survival rates were comparable across all thawing groups, with highest numbers observed in rapid-warming groups.
• Preservation of primordial follicles was significantly higher in rapid-warming groups compared to conventional thawing.
• While VEGF-A secretion was lower with commercial rapid-warming media, apoptosis levels were reduced, indicating improved tissue preservation.

Conclusions:

• Rapid-warming protocols offer comparable or superior outcomes to conventional thawing for slow-frozen human ovarian tissue.
• A universal warming protocol for ovarian tissue could enhance efficiency, reduce costs, and improve fertility preservation outcomes.