title: Cell Viability of Human Embryonic Stem Cells Stored for a Period of 9 Years.
abstract: OBJECTIVE
  Human embryonic stem cells are pluripotent cell lines usually derived from human blastocysts. Their potential critically depends on long-term proliferative capacity, developmental potential after prolonged culture, and karyotypic stability. Cell viability is an important parameter for assessing cell sample quality. Here, we elaborate the stored human embryonic stem cell lines' viability in a ready to use form for a period of 9 years (from 2007 to 2015).
  
  
  METHODS
  Spare pre implantation stage in vitro fertilized ovum-derived cell lines were cultured in suitable media. Thereafter, they were centrifuged at 1000 revolutions/min over 5 minutes, and pellets were suspended in normal saline. Next, they were tested for viability from storage at -20°C. After being allowed to thaw slowly, the cells were stained with propidium iodide and analyzed using flow cytometry. Images of cells were taken at ×40 and ×100 magnification.
  
  
  RESULTS
  At ×100 magnification, cell population size ranged from 0.2 to 2 μm. The percentage of live cells was more than 95% throughout the 9 years. Cells frozen in 2015 showed cell viability of 96.8%.
  
  
  CONCLUSIONS
  We observed high cell viability in our cell lines for 9 years. Human embryonic stem cell lines in a ready-to-use form can be preserved for long-term purposes. Thus, they could be made available globally.
authors.affiliation: From the Nutech Mediworld, New Delhi, India.
authors.forename: Geeta
authors.initials: G
authors.lastname: Shroff
authors.forename: Damini
authors.initials: D
authors.lastname: Vatsa
mesh_terms: D001755:Blastocyst / Q000166:cytology*; D002460:Cell Line; D002470:Cell Survival; D015925:Cryopreservation; D005307:Fertilization in Vitro; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000737:chemistry; D000066449:Human Embryonic Stem Cells / Q000473:pathology*; D006801:Humans; D008856:Microscopy, Fluorescence; D011419:Propidium / Q000737:chemistry; D013997:Time Factors
chemical_list: D005456:Fluorescent Dyes; D011419:Propidium