Implantation rates of embryos generated from slow cooled human oocytes from young women are comparable to those of fresh and frozen embryos from the same age group

Gook, Debra A.; Edgar, David

doi:10.1007/s10815-011-9678-6

Cited by 11 publications

(5 citation statements)

References 53 publications

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“…Although the fertilisation rate in the present study is lower than previously reported for our fresh oocytes and slow frozen oocytes [38], this is probably due to the change from use of donor sperm in cases of failed testicular retrieval [38] to fertilisation with testicular sperm obtained from repeated attempts at testicular biopsy in the majority of cases in the present study. The fertilisation rate for fresh oocytes using testicular sperm in our clinic during the same time period is 61.4 % (1227/1998).…”

Section: Discussioncontrasting

confidence: 86%

Closed vitrification of human oocytes and blastocysts: outcomes from a series of clinical cases

Gook

Choo

Bourne

et al. 2016

J Assist Reprod Genet

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Purpose High survival rates and clinical outcomes similar to those from fresh oocytes and blastocysts have been observed with open oocyte vitrification systems. It has been suggested that the extremely fast cooling rates that are only achieved with open systems are necessary for human oocyte and blastocyst vitrification. However, there is a potential risk of introducing contamination with open systems. The aim of this study was to assess whether similar survival and subsequent implantation rates could be achieved using a closed vitrification system for human oocytes and blastocysts. Methods Initially, donated immature oocytes that were matured in vitro were vitrified using the cryoprotectants ethylene glycol (EG) + dimethyl sulphoxide (DMSO) + sucrose and either a closed system (Rapid-i®) or an open system (Cryolock). The closed system was subsequently introduced clinically for mature oocyte cryopreservation cases and blastocyst vitrification. Results Using in vitro matured oocytes, a similar survival was achieved with the open system of 92.4 % (73/79) and with the closed system of 89.7 % (35/39). For clinical oocyte closed vitrification, high survival rate of 90.5 % (374/413) and an implantation rate of 32.7 % (18/55) from the transfer of day 2 embryos was achieved, which is similar to fresh day 2 embryo transfers. Blastocysts have also been successfully cryopreserved using the Rapid-i closed vitrification system with 94 % of blastocysts having an estimated ≥75 % of cells intact and a similar implantation rate (31.5 %) to fresh single blastocyst transfers. Conclusion Closed vitrification can achieve high survival and similar implantation rates to fresh for both oocytes and blastocysts.

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Section: Discussioncontrasting

confidence: 86%

Closed vitrification of human oocytes and blastocysts: outcomes from a series of clinical cases

Gook

Choo

Bourne

et al. 2016

J Assist Reprod Genet

Self Cite

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“…This slow-cooling protocol maintains the survival, fertilization, cleavage rates and embryo quality reported for previous protocols (Fabbri et al, 2001;Gook and Edgar, 2011) while pregnancy and implantation rate are significantly improved. Oocyte slow freezing performed with a modified protocol can give good and consistent outcomes.…”

Section: Clinical Outcomes With Slow Freezingmentioning

confidence: 67%

The Alpha consensus meeting on cryopreservation key performance indicators and benchmarks: proceedings of an expert meeting

Medicine¹

2012

Reproductive BioMedicine Online

100

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This proceedings report presents the outcomes from an international workshop designed to establish consensus on: definitions for key performance indicators (KPIs) for oocyte and embryo cryopreservation, using either slow freezing or vitrification; minimum performance level values for each KPI, representing basic competency; and aspirational benchmark values for each KPI, representing best practice goals. This report includes general presentations about current practice and factors for consideration in the development of KPIs. A total of 14 KPIs were recommended and benchmarks for each are presented. No recommendations were made regarding specific cryopreservation techniques or devices, or whether vitrification is 'better' than slow freezing, or vice versa, for any particular stage or application, as this was considered to be outside the scope of this workshop.

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“…However, CPA loading takes longer at reduced temperatures due to decreased membrane permeability [57; 72]; the extended exposure to CPA in the loading solution may, paradoxically, increase damage caused by chemical cytotoxicity. Alternatively, it might be possible to minimize the toxicity effects by loading penetrating CPAs at modestly elevated temperatures, thus minimizing the duration of CPA exposure [26]. This approach offers additional benefits in terms of avoiding chilling injury.…”

Section: Discussionmentioning

confidence: 99%

Optimization of cryoprotectant loading into murine and human oocytes

et al. 2014

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Loading of cryoprotectants into oocytes is an important step of the cryopreservation process, in which the cells are exposed to potentially damaging osmotic stresses and chemical toxicity. Thus, we investigated the use of physics-based mathematical optimization to guide design of cryoprotectant loading methods for mouse and human oocytes. We first examined loading of 1.5 M dimethylsulfoxide (Me2SO) into mouse oocytes at 23°C. Conventional one-step loading resulted in rates of fertilization (34%) and embryonic development (60%) that were significantly lower than those of untreated controls (95% and 94%, respectively). In contrast, the mathematically optimized two-step method yielded much higher rates of fertilization (85%) and development (87%). To examine the causes for oocyte damage, we performed experiments to separate the effects of cell shrinkage and Me2SO exposure time, revealing that neither shrinkage nor Me2SO exposure single-handedly impairs the fertilization and development rates. Thus, damage during one-step Me2SO addition appears to result from interactions between the effects of Me2SO toxicity and osmotic stress. We also investigated Me2SO loading into mouse oocytes at 30°C. At this temperature, fertilization rates were again lower after one-step loading (8%) in comparison to mathematically optimized two-step loading (86%) and untreated controls (96%). Furthermore, our computer algorithm generated an effective strategy for reducing Me2SO exposure time, using hypotonic diluents for cryoprotectant solutions. With this technique, 1.5 M Me2SO was successfully loaded in only 2.5 min, with 92% fertilizability. Based on these promising results, we propose new methods to load cryoprotectants into human oocytes, designed using our mathematical optimization approach.

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Implantation rates of embryos generated from slow cooled human oocytes from young women are comparable to those of fresh and frozen embryos from the same age group

Cited by 11 publications

References 53 publications

Closed vitrification of human oocytes and blastocysts: outcomes from a series of clinical cases

Closed vitrification of human oocytes and blastocysts: outcomes from a series of clinical cases

The Alpha consensus meeting on cryopreservation key performance indicators and benchmarks: proceedings of an expert meeting

Optimization of cryoprotectant loading into murine and human oocytes

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