A single “universal warming protocol” for vitrified human embryos: a randomized controlled study

Abstract

vitrification (CV) in a paired design. Cryopreserved tissues were thawed 8-10 weeks later and evaluated on thaw (0h) and after 24-96h culture. Formalin fixed, paraffinembedded blocks were serially sectioned and primordial (pdf) and primary (pyf) follicle densities, % of pdf and pyf with DNA double-strand breaks (by gH2AX) and apoptotic cell death pathway activation (AC3) were determined. RESULTS: The data are summarized in Table 1. Compared to OV, pdf and pyf densities were similar in the CV group after thawing. Likewise, the percentages of apoptotic and DNA-damaged pdf did not differ between the OVand CV groups on the thaw day. However, the percentage of apoptotic pdf was significantly reduced in the CV group compared to the OV after 96h in culture (p¼0.03). CONCLUSIONS: Our results show that the newly developed CV system provides similar or better efficacy compared to open vitrification with human ovarian tissue. The mechanism of higher primordial follicle survival rate with CVafter 96h culture needs to be further explored. Having showed that the OV has similar efficacy to slow freezing with ovarian tissues (see abstract 2017-A-2005-ASRM), we propose that the CV method should become the standard method of ovarian tissue cryopreservation.

A monocentric analysis of the efficacy of extracellular cryoprotectants in unfrozen solutions for cleavage stage embryos

“…In this perspective, kit 3 fits better both features of vitrification compared to kits 1 and 2, resulting in accordance with the rationale of a previous study demonstrating that, irrespective of the freezing protocol, a rapid warming procedure by stepwise dilutions of extracellular cryoprotectants only, as sucrose, may be adopted for higher survival rate of both slow-frozen and vitrified reproductive cells [34]. The use of only extracellular cryoprotectant (sucrose or threalose) in the thawing solution seems to be the best option for any frozen cell or tissue, as confirmed by the studies on clinical efficiency of Parmegiani’s Universal Warming [40, 41].…”

A comprehensive review and update on human fertility cryopreservation methods and tools

“…Notably, in 2014 Parmegiani and colleagues published a pilot study, suggesting a “universal warming protocol” (extracellular CPAs 1–0.5 M) as an efficient protocol for warming ( 61 ). Later on, in 2017 they applied this protocol on commercial brand kits (Kitazato and Sega kits containing trehalose and sucrose, respectively), proposing that a combination of different kits is efficient for the vitrification/thawing of embryos ( 62 ). Moreover, in regard to embryo vitrification and particularly in re-vitrification, interesting results have been found in the re-vitrification of 8 cells and blastocysts.…”