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Cryopreservation of Human Bone Marrow Grafts
Published in Adrian P. Gee, BONE MARROW PROCESSING and PURGING, 2020
A new development in cryobiology is the use of vitrification for cryopreservation. If ice formation can be prevented, by a combination of high solute concentration and rapid cooling, a solution will become glassy, rather than crystalline, at low temperature. The problems associated with ice formation are avoided and, provided thawing is rapid enough to prevent ice growth during warming, excellent cryopreservation is possible.59 Chemicals such as polyethylene glycol, glycerol, DMSO, HES, acetamide, and propanediol have been found to be effective in promoting vitrification in cell-free solutions.59 Red cells,60 monocytes,61 ova,62,63 embryos,64,65 and islets66 have been vitrified and thawed with good survival. This approach is under active investigation for the cryopreservation of organs,59,67 and has the potential to be an alternative approach to the preservation of bone marrow.
Cellular Injury Associated with Organ Cryopreservation: Chemical Toxicity and Cooling Injury
Published in John J. Lemasters, Constance Oliver, Cell Biology of Trauma, 2020
Gregory M. Fahy, Carla da Mouta, Latchezar Tsonev, Bijan S. Khirabadi, Patrick Mehl, Harold T. Meryman
Organ cryopreservation is a frontier discipline both in cryobiology and in pathology. Cryopreservation refers to preservation at cryogenic temperatures, which for our present purposes will be considered any temperature below about -100°C. For organ cryopreservation to succeed, it is necesary that the organ survive low-temperature exposure per se, and it appears necessary for the organ to survive exposure to certain chemical agents (known generically as cryoprotective agents [CPAs] or cryoprotectants) at concentrations so high that they preclude ice formation during cooling.1 Aqueous solutions that do not freeze upon cooling eventually revert to the glassy state, a glass being a liquid the molecular motions of which have been largely arrested.2 This conversion to the glassy state is referred to as vitrification, and organ cryopreservation in the absence of ice is referred to as organ vitrification.
The human oocyte: Controlled-rate cooling Controlled-rate cooling
Published in David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham, Textbook of Assisted Reproductive Techniques, 2017
Cryobiology is the branch of biology that studies the effects of low temperatures on living systems. The basic principles of cryobiology must be well known in order to get good results. Cryopreservation requires the biological sample to be brought to cryogenic temperature (—196°C) at which biological, chemical, and physical activities come to a stop. The factors playing a fundamental role in cryopreservation are biophysical—such as cryoprotectant and speed—and morphological—such as dimensions and quality of sample. For these reasons, cryopreservation of human oocytes, because of their unique features of size and physiology, experiences several difficulties.
Protein evolution revisited
Published in Systems Biology in Reproductive Medicine, 2018
Peter L. Davies, Laurie A. Graham
The ability of AFPs to control ice growth, and in particular to inhibit the recrystallization of ice in the frozen materials, has led to many experimental applications of AFPs in cryobiology. Although cryopreservation is not the focus of this memorial review article, it may be of interest to readers of Systems Biology in Reproductive Medicine to know that AFPs are being used to try to increase the viability of frozen sperm (Prathalingam et al. 2006; Qadeer et al. 2014; Zilli et al. 2014) and embryos (Baguisi et al. 1997; Martínez-Páramo et al. 2009; Ideta et al. 2015).
Should artificial shrinkage be performed prior to blastocyst vitrification? A systematic review of the literature and meta-analysis
Published in Human Fertility, 2022
Juliette Boyard, Arnaud Reignier, Sana Chtourou, Tiphaine Lefebvre, Paul Barrière, Thomas Fréour
Blastocyst collapse considerably reduces the volume of the blastocoelic cavity, and theoretically leads to a significantly decreased risk of cellular damage. Indeed, it improves the penetration of cryoprotectant agents inside the cavity, reducing the formation of ice crystals responsible for embryo lysis during vitrification-warming process. Thus, this technique may increase the chance of blastocyst survival after warming, and subsequently improved clinical outcome of FBT cycles. Despite this convincing rationale, the studies included in this review have yielded conflicting results. The huge heterogeneity observed between these studies in terms of population, design, methods, bias, and outcomes might explain these discordant conclusions. In this respect, meta-analysis can be a useful tool providing a relevant overview and interpretation. It allowed us to find that blastocyst survival rate and clinical pregnancy rate were significantly improved in the AS group as compared to the control group. Conversely, implantation rate and live birth rate did not appear to be significantly improved after blastocyst collapse. These apparently contradictory results should be interpreted with care owing to the number and characteristics of the studies included in this meta-analysis. First, only 3 studies reported live birth, while 6 to 8 were used for the other outcomes. It should also be noted that 14 years separated the most recent and the oldest studies included in the analysis. It can be easily speculated that procedures, equipment and culture media have significantly changed over this long period, potentially limiting the relevance of comparing the results obtained in these studies. As survival is defined by >50% cells intact and not blastocyst full re-expansion which is critical for implantation, it is likely that some blastocysts used for transfer in these studies were not fully re-expanded, thus potentially accounting for the different conclusions found for survival on one hand, and clinical outcome on the other hand. Additionally, the type of solutions that shrinkage and control was performed in was not specified in most studies, thus not allowing to determine if some solutions are associated with increased clinical benefit of blastocyst artificial shrinkage. In this respect, further studies on cryobiology should be considered in order to improve the knowledge on the phenomena associated with blastocyst survival and implantation potential respectively.