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Review
. 2017 Apr 5;16(2):118-125.
doi: 10.1002/rmb2.12027. eCollection 2017 Apr.

Theory about the Embryo Cryo-Treatment

Iavor K Vladimirov  1   2 , Desislava Tacheva  1   2 , Antonio Diez  3   4   5
Affiliations
Review

Theory about the Embryo Cryo-Treatment

Iavor K Vladimirov et al. Reprod Med Biol. .

Abstract

Background: To create hypothesis, which can give a logical explanation related to the benefits of freezing/thawing embryos. Cryopreservation is not only a technology used for storing embryos, but also a method of embryo treatment that can potentially improve the success rate in infertile couples.

Methods: From the analysis of multiple results in assisted reproductive technology, which have no satisfactory explanation to date, we found evidence to support a 'therapeutic' effect of the freezing/thawing of embryos on the process of recovery of the embryo and its subsequent implantation.

Results: Freezing/thawing is a way to activate the endogenous survival and repair responses in preimplantation embryos. Several molecular mechanisms can explain the higher success rate of ET using thawed embryos compared to fresh ET in women of advanced reproductive age, the higher miscarriage rate in cases of thawed blastocyst ET compared to thawed ET at early cleavage embryo, and the higher perinatal parameters of born children after thawed ET. Embryo thawing induces a stress. Controlled stress is not necessarily detrimental, because it generates a phenomenon that is counteracted by several known biological responses aimed to repair mitochondrial damage of membrane and protein misfolding. The term for favorable biological responses to low exposures to stress is called hormesis.

Conclusions: This thesis will summarize the role of cryopreservation in the activation of a hormetic response, preserving the mitochondrial function, improving survival, and having an impact on the process of implantation, miscarriage, and the development of pregnancy.

Keywords: cryopreservation; embryo; embryo transfer; mitochondria; pregnancy.

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Figures

Figure 1
Figure 1
Mitochondrial biogenesis and mitochondrial DNA (mtDNA) replication.44 License No. 4032020938571, Hum Reprod Update. The replication of mtDNA is significantly reduced during pre‐implantation development, with increases only taking place in the trophectoderm in order to aid implantation. ATP, adenosine triphosphate; ESC, embryonic stem cell; ICM, inner cell mass; PGC, primordial germ cell
Figure 2
Figure 2
Effect of hormesis on the implantation activity of embryos during a change in the development conditions
Figure 3
Figure 3
Decrease of mitochondrial activity and the levels of reactive oxygen species (ROS) in the embryo after freezing and thawing procedures
Figure 4
Figure 4
Effect that the freezing and thawing of embryos has on the levels of reactive oxygen species (ROS), mitochondrial DNA (mtDNA) mutations, and live birth rate in different ages of women. ET, embryo transfer; FET, frozen embryo transfer
Figure 5
Figure 5
Effect of embryo freezing and thawing on the displacement of the mitochondrial levels in different ages of women and how it is related to the delivery rate. mtScore, method of assessing the level of mitochondrial activity
See this image and copyright information in PMC

References

    1. Cobo A, de los Santos MJ, Castellò D, Gámiz P, Campos P, Remohí J. Outcomes of vitrified early cleavage‐stage and blastocyst‐stage embryos in a cryopreservation program: evaluation of 3,150 warming cycles. Fertil Steril. 2012;98:1138‐1146. - PubMed
    1. IVF success rate reports 2004–2013. Society for Assisted Reproductive Technology Web site. https://www.sartcorsonline.com/rptCSR_PublicMultYear.aspx?ClinicPKID=0. Accessed December 11, 2015.
    1. Estill MS, Bolnick JM, Waterland RA, Bolnick AD, Diamond MP, Krawetz SA. Assisted reproductive technology alters deoxyribonucleic acid methylation profiles in bloodspots of newborn infants. Fertil Steril. 2016;106:629‐639. - PubMed
    1. Wang YA, Costello M, Chapman M, Black D, Sullivan EA. Transfers of fresh blastocysts and blastocysts cultured from thawed cleavage embryos are associated with fewer miscarriages. Reprod Biomed Online. 2011;23:777‐788. - PubMed
    1. Maheshwari A, Pandey S, Shetty A, Hamilton M, Bhattacharya S. Obstetric and perinatal outcomes in singleton pregnancies resulting from the transfer of frozen thawed versus fresh embryos generated through in vitro fertilization treatment: a systematic review and meta‐analysis. Fertil Steril. 2012;98:368‐377. - PubMed

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