title: Slow controlled-rate freezing of human in vitro matured oocytes: effects on maturation rate and kinetics and parthenogenetic activation.
abstract: OBJECTIVE
  To create a pool of frozen donated human oocytes and find the optimal stage for slow controlled-rate freezing of human in vitro matured oocytes.
  
  
  METHODS
  Oocytes at different developmental stages of maturation (germinal vesicle, metaphase I, or metaphase II) and oocytes that failed to fertilize after IVF or intracytoplasmic sperm injection (ICSI) were frozen using a slow controlled-rate freezing protocol. Frozen/thawed oocytes were artificially activated to verify activation potential and compared with oocytes that were not frozen.
  
  
  METHODS
  University hospital-based fertility center.
  
  
  METHODS
  Stimulated patients undergoing IVF/ICSI treatment donated oocytes left over during their infertility treatment.
  
  
  METHODS
  Human oocytes were frozen at different stages of maturation. Fresh and frozen/thawed oocytes were activated by electrical pulses followed by incubation in 6-dimethylaminopurine.
  
  
  METHODS
  Survival rate, maturation rate and kinetics, and activation potential.
  
  
  RESULTS
  Human oocytes at all developmental stages have high survival rates after slow controlled-rate freezing. Frozen/thawed germinal vesicle oocytes showed decreased and delayed maturation after thawing. Activation potential was not affected.
  
  
  CONCLUSIONS
  A pool of donated human oocytes could be established using slow controlled-rate freezing. Immature oocytes should be frozen after in vitro maturation.
authors.affiliation: Department of Reproductive Medicine, Ghent University Hospital, Ghent, Belgium. karen.versieren@ugent.be
authors.forename: Karen
authors.initials: K
authors.lastname: Versieren
authors.forename: Björn
authors.initials: B
authors.lastname: Heindryckx
authors.forename: Thomas
authors.initials: T
authors.lastname: O'Leary
authors.forename: Ilse
authors.initials: I
authors.lastname: De Croo
authors.forename: Etienne
authors.initials: E
authors.lastname: Van den Abbeel
authors.forename: Jan
authors.initials: J
authors.lastname: Gerris
authors.forename: Petra
authors.initials: P
authors.lastname: De Sutter
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D002470:Cell Survival / Q000502:physiology; D015925:Cryopreservation / Q000379:methods*; D004558:Electric Stimulation; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D066298:In Vitro Techniques; D018587:Oocyte Donation; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D010312:Parthenogenesis / Q000502:physiology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013268:Stimulation, Chemical
chemical_list: D047428:Protein Kinase Inhibitors; C001020:N(6),N(6)-dimethyladenine; D000225:Adenine