title: New methods for cooling and storing oocytes and embryos in a clean environment of -196°C.
abstract: It is well documented that oocyte vitrification using open systems provides better results than closed systems. However, its use is limited owing to risks of contamination posed by direct exposure to liquid nitrogen and cross-contamination when stored in liquid nitrogen tanks. A device that produces clean liquid air (CLAir) having similar a temperature as liquid nitrogen and a sterile storage canister device (Esther) that keeps samples sealed in their own compartment while in regular liquid nitrogen tanks were developed. The following experiments were performed: temperature measurements, bioburden tests, vitrification and storage experiments with mice embryos and human oocytes. Results showed similar cooling rates for liquid nitrogen and liquid air. Bioburden tests of CLAir and Esther showed no contamination, while massive contamination was found in "commercial" liquid nitrogen and storage canisters. Mice blastocysts had a survival rate of over 90%, with 80% hatching rate after vitirification in CLAir and 1 week storage in Esther, similar to the fresh (control) results. Human oocytes vitrified in CLAir and in liquid nitrogen for three consecutive vitrification/warming cycles showed 100% survival, seen as re-expansion in both groups. These new systems represent a breakthrough for safe vitrification using open systems and a safe storage process generally.
authors.affiliation: FertileSafe Ltd, 11 HaHarash St, Nes-Ziona 7403118, Israel. Electronic address: fertilesafe@gmail.com.
authors.forename: Amir
authors.initials: A
authors.lastname: Arav
authors.affiliation: FertileSafe Ltd, 11 HaHarash St, Nes-Ziona 7403118, Israel.
authors.forename: Yehudit
authors.initials: Y
authors.lastname: Natan
authors.affiliation: Unita' Operativa di Medicina della Riproduzione, Istituto Clinico Humanitas, Rozzano, Milan, Italy.
authors.forename: Paolo Emanuele
authors.initials: PE
authors.lastname: Levi-Setti
authors.affiliation: Unita' Operativa di Medicina della Riproduzione, Istituto Clinico Humanitas, Rozzano, Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Menduni
authors.affiliation: Dept. Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, Yale University Fertility Center, New Haven, CT, USA.
authors.forename: Pasquale
authors.initials: P
authors.lastname: Patrizio
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology; D003080:Cold Temperature; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000627:therapeutic use*; D046149:Embryo Culture Techniques / Q000379:methods*; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009865:Oocytes / Q000166:cytology; D010100:Oxygen / Q000737:chemistry; D058989:Vitrification
chemical_list: D003451:Cryoprotective Agents; D010100:Oxygen
keywords: closed systems; contamination; liquid nitrogen; open systems; storage; vitrification