Oocyte cryopreservation: the birth of the first Hungarian babies from frozen oocytes

Konc, János; Kanyó, Katalin; Varga, Erika; Kriston, Rita; Cseh, Sándor

doi:10.1007/s10815-008-9235-0

Cited by 9 publications

(5 citation statements)

References 20 publications

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“…The best suitable cooling rate is cell type-specific [ 12 ]. Oocytes, for example, could be recovered well upon thawing when they were slowly cooled (−0.3 °C/min) to −30 °C, followed by a faster cooling (−50 °C/min) to −150 °C before submerging them into liquid nitrogen [ 18 ]. Human oocytes are very susceptible to damage by ice crystals during freezing and thawing because of their large surface area/volume ratio and plasma membrane permeability [ 19 ].…”

Section: Cryopreservationmentioning

confidence: 99%

“…During a successful vitrification process, ice formation is completely prevented. However, for many vitrification protocols, a high concentration of cryoprotectants is needed, and this is usually toxic for sensitive cells such as stem cells and oocytes [ 18 , 21 , 72 , 73 , 74 , 75 ]. The higher the cooling rate, the lower the cryoprotectant concentration needed for vitrification, and thus the lower the cytotoxicity [ 76 ].…”

Section: Cryopreservationmentioning

confidence: 99%

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Improving Cell Recovery: Freezing and Thawing Optimization of Induced Pluripotent Stem Cells

Uhrig

Ezquer

2022

Cells

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Achieving good cell recovery after cryopreservation is an essential process when working with induced pluripotent stem cells (iPSC). Optimized freezing and thawing methods are required for good cell attachment and survival. In this review, we concentrate on these two aspects, freezing and thawing, but also discuss further factors influencing cell recovery such as cell storage and transport. Whenever a problem occurs during the thawing process of iPSC, it is initially not clear what it is caused by, because there are many factors involved that can contribute to insufficient cell recovery. Thawing problems can usually be solved more quickly when a certain order of steps to be taken is followed. Under optimized conditions, iPSC should be ready for further experiments approximately 4–7 days after thawing and seeding. However, if the freezing and thawing protocols are not optimized, this time can increase up to 2–3 weeks, complicating any further experiments. Here, we suggest optimization steps and troubleshooting options for the freezing, thawing, and seeding of iPSC on feeder-free, Matrigel™-coated, cell culture plates whenever iPSC cannot be recovered in sufficient quality. This review applies to two-dimensional (2D) monolayer cell culture and to iPSC, passaged, frozen, and thawed as cell aggregates (clumps). Furthermore, we discuss usually less well-described factors such as the cell growth phase before freezing and the prevention of osmotic shock during thawing.

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Section: Cryopreservationmentioning

confidence: 99%

Section: Cryopreservationmentioning

confidence: 99%

Improving Cell Recovery: Freezing and Thawing Optimization of Induced Pluripotent Stem Cells

Uhrig

Ezquer

2022

Cells

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“…This difference in membrane permeability may have a strong impact on the outcome of slow freezing of oocytes but can be controlled by the elevation of the concentration of the nonpermeable CPA and the environmental temperature [ 20 , 21 ]. By having the concentration of nonpermeating CPA increased (sucrose: 0.2 and 0.3 M) higher survival rates were reported, and the overall fertilization rates of frozen-thawed oocytes appeared to be similar to those of fresh oocytes [ 20 , 22 – 28 ].…”

Section: Traditional Slow Cooling Of Embryos and Oocytesmentioning

confidence: 99%

“…Since the first successes achieved in the field of human oocyte CP many changes have been introduced into the slow cooling procedure. Increasing the sucrose concentration both in the slow freezing and vitrification solutions (from 0.1 M to 0.3 M) increased the rate of dehydration and the survival and fertilization rates of MII oocytes in a dose-dependent manner [ 20 , 22 – 28 ]. Changing the temperature of the equilibration with CPA, ice nucleation (seeding) and plunging embryos into LN 2 , replacing sodium with choline (low sodium medium), or injecting sucrose directly into the cytoplasm of the oocyte all improved oocyte survival [ 32 , 61 , 62 ].…”

Section: Practical Experiences With Human Oocyte Cryopreservation mentioning

confidence: 99%

Cryopreservation of Embryos and Oocytes in Human Assisted Reproduction

Konc

Kanyó

Kriston

et al. 2014

BioMed Research International

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Both sperm and embryo cryopreservation have become routine procedures in human assisted reproduction and oocyte cryopreservation is being introduced into clinical practice and is getting more and more widely used. Embryo cryopreservation has decreased the number of fresh embryo transfers and maximized the effectiveness of the IVF cycle. The data shows that women who had transfers of fresh and frozen embryos obtained 8% additional births by using their cryopreserved embryos. Oocyte cryopreservation offers more advantages compared to embryo freezing, such as fertility preservation in women at risk of losing fertility due to oncological treatment or chronic disease, egg donation, and postponing childbirth, and eliminates religious and/or other ethical, legal, and moral concerns of embryo freezing. In this review, the basic principles, methodology, and practical experiences as well as safety and other aspects concerning slow cooling and ultrarapid cooling (vitrification) of human embryos and oocytes are summarized.

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“…Furthermore, while visualization of the meiotic spindle may perhaps provide insight into oocyte maturational or possibly chromosomal status [42,47,49,53,54], these applications are compromised by the fact that the meiotic spindle is a dynamic structure [55,56], affected by environmental conditions such as temperature. Thus, studies that have attempted to use spindle visualization to assess efficacy of cryoprotectant exposure or cryopreservation protocols often have conflicting results because other variables, such as temperature, are not controlled [43,[57][58][59][60][61][62][63]. Additionally, some laboratories have even tried to use the intensity of the birefringent signal, or retardance, as a measure of spindle density and oocyte quality [44,45,[64][65][66].…”

Section: Polarized Light Microscopymentioning

confidence: 99%

Peering Beneath the Surface: Novel Imaging Techniques to Noninvasively Select Gametes and Embryos for ART

Jasensky

Swain

2013

Biology of Reproduction

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Embryo imaging has long been a critical tool for in vitro fertilization laboratories, aiding in morphological assessment of embryos, which remains the primary tool for embryo selection. With the recent emergence of clinically applicable real-time imaging systems to assess embryo morphokinetics, a renewed interest has emerged regarding noninvasive methods to assess gamete and embryo development as a means of inferring quality. Several studies exist that utilize novel imaging techniques to visualize or quantify intracellular components of gametes and embryos with the intent of correlating localization of organelles or molecular constitution with quality or outcome. However, the safety of these approaches varies due to the potential detrimental impact of light exposure or other variables. Along with complexity of equipment and cost, these drawbacks currently limit clinical application of these novel microscopes and imaging techniques. However, as evidenced by clinical incorporation of some real-time imaging devices as well as use of polarized microscopy, some of these imaging approaches may prove to be useful. This review summarizes the existing literature on novel imaging approaches utilized to examine gametes and embryos. Refinement of some of these imaging systems may permit clinical application and serve as a means to offer new, noninvasive selection tools to improve outcomes for various assisted reproductive technology procedures.

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Oocyte cryopreservation: the birth of the first Hungarian babies from frozen oocytes

Abstract: Egg freezing is not a routine procedure yet, but there will certainly be a place for it in the future of assisted reproductive medicine.

Cited by 9 publications

References 20 publications

Improving Cell Recovery: Freezing and Thawing Optimization of Induced Pluripotent Stem Cells

Improving Cell Recovery: Freezing and Thawing Optimization of Induced Pluripotent Stem Cells

Cryopreservation of Embryos and Oocytes in Human Assisted Reproduction

Peering Beneath the Surface: Novel Imaging Techniques to Noninvasively Select Gametes and Embryos for ART

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