TY - JOUR
T1 - Chromosomal meiotic segregation, embryonic developmental kinetics and DNA (hydroxy)methylation analysis consolidate the safety of human oocyte vitrification
AU - De Munck, N
AU - Petrussa, L
AU - Verheyen, G
AU - Staessen, C
AU - Vandeskelde, Y
AU - Sterckx, Johan
AU - Bocken, G
AU - Jacobs, K
AU - Stoop, D
AU - De Rycke, M
AU - Van de Velde, H
N1 - © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: [email protected].
PY - 2015
Y1 - 2015
N2 - Oocyte vitrification has been introduced into clinical settings without extensive pre-clinical safety testing. In this study, we analyzed major safety aspects of human oocyte vitrification in a high security closed system: (i) chromosomal meiotic segregation, (ii) embryonic developmental kinetics and (iii) DNA (hydroxy)methylation status. Fresh and vitrified sibling oocytes from young donors after ICSI were compared in three different assays. First, the chromosomal constitution of the fertilized zygotes was deduced from array comparative genomic hybridization results obtained from both polar bodies biopsied at day 1. Secondly, embryo development up to day 3 was analyzed by time-lapse imaging. Ten specific time points, six morphokinetic time intervals and the average cell number on day 3 were recorded. Thirdly, global DNA methylation and hydroxymethylation patterns were analyzed by immunostaining on day 3 embryos. The nuclear fluorescence intensity was measured by Volocity imaging software. Comprehensive chromosomal screening of the polar bodies demonstrated that at least half of the zygotes obtained after ICSI of fresh and vitrified oocytes were euploid. Time-lapse analysis showed that there was no significant difference in cleavage timings, the predictive morphokinetic time intervals nor the average cell number between embryos developed from fresh and vitrified oocytes. Finally, global DNA (hydroxy)methylation patterns were not significantly different between day 3 embryos obtained from fresh and from vitrified oocytes. Our data further consolidate the safety of the oocyte vitrification technique. Nevertheless, additional testing in young and older subfertile / infertile patients and sound follow-up studies of children born after oocyte cryopreservation remain mandatory.
AB - Oocyte vitrification has been introduced into clinical settings without extensive pre-clinical safety testing. In this study, we analyzed major safety aspects of human oocyte vitrification in a high security closed system: (i) chromosomal meiotic segregation, (ii) embryonic developmental kinetics and (iii) DNA (hydroxy)methylation status. Fresh and vitrified sibling oocytes from young donors after ICSI were compared in three different assays. First, the chromosomal constitution of the fertilized zygotes was deduced from array comparative genomic hybridization results obtained from both polar bodies biopsied at day 1. Secondly, embryo development up to day 3 was analyzed by time-lapse imaging. Ten specific time points, six morphokinetic time intervals and the average cell number on day 3 were recorded. Thirdly, global DNA methylation and hydroxymethylation patterns were analyzed by immunostaining on day 3 embryos. The nuclear fluorescence intensity was measured by Volocity imaging software. Comprehensive chromosomal screening of the polar bodies demonstrated that at least half of the zygotes obtained after ICSI of fresh and vitrified oocytes were euploid. Time-lapse analysis showed that there was no significant difference in cleavage timings, the predictive morphokinetic time intervals nor the average cell number between embryos developed from fresh and vitrified oocytes. Finally, global DNA (hydroxy)methylation patterns were not significantly different between day 3 embryos obtained from fresh and from vitrified oocytes. Our data further consolidate the safety of the oocyte vitrification technique. Nevertheless, additional testing in young and older subfertile / infertile patients and sound follow-up studies of children born after oocyte cryopreservation remain mandatory.
U2 - 10.1093/molehr/gav013
DO - 10.1093/molehr/gav013
M3 - Article
C2 - 25833840
VL - 21
SP - 535
EP - 544
JO - Molecular Human Reproduction
JF - Molecular Human Reproduction
SN - 1360-9947
IS - 6
ER -