title: Rapid warming increases survival of slow-frozen sibling oocytes: a step towards a single warming procedure irrespective of the freezing protocol?
abstract: Nowadays, human oocytes/embryos are cryopreserved via slow freezing or vitrification. The aim of this study was to evaluate a rapid warming protocol for slow-frozen human oocytes based on the standard warming procedure for vitrification. This was a prospective study on 216 sibling oocytes randomized for either conventional rapid thawing or rapid warming with vitrification warming solution. The primary endpoint was morphological assessment of survival at 2h. Surviving oocytes were divided into two subgroups: (i) parthenogenetically activated; and (ii) fixed and observed for spindle/chromosome configuration. Secondary endpoints were parthenogenetic development and spindle/metaphase configuration. Survival rate with rapid warming was higher (92/102, 90.2%) than with rapid thawing (85/114, 74.6%; P=0.005), and after 3d of culture the rapidly warmed parthenotes had more blastomeres compared with those rapidly thawed (P=0.042). Meiotic spindle and chromosomal configuration were not significantly influenced by rapid warming or rapid thawing. The finding of this study allows IVF centres to increase the efficiency of oocyte slow freezing, enabling survival rates comparable to vitrification protocols, and potentially to optimize costs by using the same warming protocol for both slow-frozen and vitrified reproductive cells.
authors.affiliation: Reproductive Medicine Unit, GynePro Medical Centers, Bologna, Italy. Electronic address: l.parmegiani@gynepro.it.
authors.forename: Lodovico
authors.initials: L
authors.lastname: Parmegiani
authors.affiliation: Department of Life, Health, and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Tatone
authors.affiliation: Reproductive Medicine Unit, GynePro Medical Centers, Bologna, Italy.
authors.forename: Graciela Estela
authors.initials: GE
authors.lastname: Cognigni
authors.affiliation: Reproductive Medicine Unit, GynePro Medical Centers, Bologna, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Bernardi
authors.affiliation: Reproductive Medicine Unit, GynePro Medical Centers, Bologna, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Troilo
authors.affiliation: Reproductive Medicine Unit, GynePro Medical Centers, Bologna, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Arnone
authors.affiliation: Reproductive Medicine Unit, GynePro Medical Centers, Bologna, Italy.
authors.forename: Antonio Manuel
authors.initials: AM
authors.lastname: Maccarini
authors.affiliation: Department of Life, Health, and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Di Emidio
authors.affiliation: Department of Life, Health, and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Vitti
authors.affiliation: Reproductive Medicine Unit, GynePro Medical Centers, Bologna, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Filicori
mesh_terms: D000328:Adult; D018929:Cell Culture Techniques / Q000379:methods*; D002470:Cell Survival; D002875:Chromosomes / Q000502:physiology; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D005615:Freezing; D006801:Humans; D059471:In Vitro Oocyte Maturation Techniques / Q000379:methods*; D009865:Oocytes / Q000166:cytology / Q000502:physiology; D010312:Parthenogenesis / Q000502:physiology; D008941:Spindle Apparatus / Q000502:physiology; D013696:Temperature; D013997:Time Factors
keywords: oocyte slow freezing; oocyte vitrification; parthenogenetic activation; rapid thawing; universal warming protocol; warming