Aseptic vitrification of blastocysts from infertile patients, egg donors and after IVM.
During embryo vitrification, it is advisable that cooling and storage should occur in a carrier device in which there is complete separation of the embryos from liquid nitrogen to ensure asepsis. The consequence of a reduction in the cooling rate resulting from the heat-insulating barrier aseptic devices has to be counteracted by gradually increasing intracellular concentrations of cryoprotectants without inducing a toxic effect. Blastocysts originating from couples with male and/or female factor infertility (group 1) or from oocyte donors (group 2) or from in-vitro matured oocytes (group 3) were gradually exposed to increasing concentrations of dimethylsulphoxide/ethylene glycol (5/5%, 10/10% and 20/20%) before aseptic vitrification using a specially designed carrier (VitriSafe), a modification of the open hemi-straw plug device. A total of 120 aseptic vitrification/warming cycles were performed in group 1, 91 in group 2 and 22 in group 3. Survival rates before embryo transfer, ongoing pregnancy and implantation rates were as follows: for group 1, 73, 43 and 26%; for group 2, 88, 53 and 34%; and for group 3, 69, 50 and 38%, respectively. In spite of reduced cooling rates due to aseptic vitrification conditions, a three-step exposure to cryoprotectant solutions protects the embryos effectively from cryo-injuries and guaranties high survival rates.
Vanderzwalmen
P
P
IVF Centers Prof. Zech, Bregenz, Austria. pierrevdz@hotmail.com
Ectors
F
F
Grobet
L
L
Prapas
Y
Y
Panagiotidis
Y
Y
Vanderzwalmen
S
S
Stecher
A
A
Frias
P
P
Liebermann
J
J
Zech
N H
NH
D001755:Blastocyst / Q000166:cytology* / Q000187:drug effects; D015925:Cryopreservation; D003451:Cryoprotective Agents / Q000494:pharmacology; D046149:Embryo Culture Techniques / Q000295:instrumentation; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D007247:Infertility, Female; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D014019:Tissue Donors
D003451:Cryoprotective Agents