title: The derivation of two additional human embryonic stem cell lines from day 3 embryos with low morphological scores.
abstract: BACKGROUND
  Immune rejection can lead to the failure of human embryonic stem cell (hES cell) transplantation. One approach to address the problem is to establish hES cell line banks. Due to the limited source of human embryos and to ethical reasons, the hES cell lines are not readily available. This study was undertaken to determine whether discarded day 3 embryos with low morphological scores could develop into blastocysts and produce hES cell lines.
  
  
  METHODS
  A total of 130 day 3 embryos with low morphological scores were cultured to blastocyst stage, and inner cell masses (ICM) were isolated by immunosurgery. Colonies derived from the ICM were passaged every 4-7 days and evaluated for cell surface markers, differentiation potentials and karyotypes.
  
  
  RESULTS
  A total of 19 blastocysts were obtained from 130 embryos (quality score <16), which resulted in the formation of 10 ICM, and two cell lines. Both cell lines satisfied the criteria that characterize pluripotent hES cells.
  
  
  CONCLUSIONS
  Our results suggest that a subset with poor quality day 3 embryos judged on the basis of morphological assessment can form blastocysts and give rise to hES cell lines.
authors.affiliation: Neurologic Department , Tongji Hospital, Tongji Medicine College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.forename: Kun
authors.initials: K
authors.lastname: Qian
authors.forename: Juan
authors.initials: J
authors.lastname: Hu
authors.forename: Denghua
authors.initials: D
authors.lastname: Liu
authors.forename: Wenguo
authors.initials: W
authors.lastname: Lu
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Huajing
authors.initials: H
authors.lastname: Yan
authors.forename: Suming
authors.initials: S
authors.lastname: Zhang
authors.forename: Guijin
authors.initials: G
authors.lastname: Zhu
mesh_terms: D001755:Blastocyst / Q000166:cytology*; D002460:Cell Line / Q000166:cytology*; D046149:Embryo Culture Techniques; D005307:Fertilization in Vitro; D006801:Humans; D013234:Stem Cells / Q000166:cytology*; D014015:Tissue Banks