title: Comparison of three methods for cryopreservation of human embryonic stem cells.
abstract: OBJECTIVE
  To establish reliable methods for cryopreservation of human embryonic stem cells (hESCs).
  
  
  METHODS
  Prospective experimental study.
  
  
  METHODS
  University laboratory.
  
  
  METHODS
  One hESC line.
  
  
  METHODS
  The attachment rates and recovery rates of cryopreserved hESCs using three different cryopreservation methods were compared.
  
  
  METHODS
  The hESCs were frozen and thawed by conventional cryopreservation, programmable cryopreservation, and vitrification method. The efficiency of cryopreservation was assessed by attachment rate and recovery rate.
  
  
  RESULTS
  The attachment rate and recovery rate after thawing of hESCs frozen by the conventional cryopreservation method were significantly lower than those of hESCs frozen by programmed cryopreservation and vitrification methods. Vitrification resulted in the highest attachment rate and recovery rate compared with the other two methods. Human ESCs after vitrification and programmable cryopreservation still expressed pluripotent markers, maintained normal karyotype, and retained their pluripotency.
  
  
  CONCLUSIONS
  Our data show that programmable cryopreservation and vitrification methods are appropriate for cryopreservation of hESCs, whereas the conventional slow-rate freezing method is not appropriate for cryopreservation of hESCs.
authors.affiliation: Stem Cell Research Center and Department of Cell Biology, Peking University Health Science Center, Beijing 100083, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Ji-Chun
authors.initials: JC
authors.lastname: Tan
authors.forename: Ling-Song
authors.initials: LS
authors.lastname: Li
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002448:Cell Adhesion; D015925:Cryopreservation / Q000379:methods*; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000502:physiology; D006801:Humans; D007621:Karyotyping; D039904:Pluripotent Stem Cells / Q000166:cytology* / Q000502:physiology; D013696:Temperature; D013724:Teratoma / Q000473:pathology
chemical_list: D015415:Biomarkers