title: Isolation of dental pulp stem cells from a single donor and characterization of their ability to differentiate after 2 years of cryopreservation.
abstract: OBJECTIVE
  To investigate the viability and differentiation capacity of dental pulp stem cells (DPSCs) isolated from single donors after 2 years of cryopreservation.
  
  
  METHODS
  This prospective study was conducted between October 2010 and February 2014 in the Stem Unit, College of Medicine, King Saud University, Riyadh, Saudi Arabia. Seventeen teeth extracted from 11 participants were processed separately to assess the minimum tissue weight needed to yield cells for culturing in vitro. Cell stemness was evaluated before passage 4 using the colony forming unit assay, immunofluorescence staining, and bi-lineage differentiation. Dental pulp stem cells  were cryopreserved for 2 years. Post-thaw DPSCs were cultured until senescence and differentiated toward osteogenic, odontogenic, adipogenic, and chondrogenic lineages.
  
  
  RESULTS
  Viable cells were isolated successfully from 6 of the 11 participants. Three of these 6 cultured cell lines were identified as DPSCs. A minimum of 0.2 g of dental pulp tissue was required for successful isolation of viable cells from a single donor. Post-thaw  DPSCs successfully differentiated towards osteogenic, odontogenic, chondrogenic, and adipogenic lineages. The post-thaw DPSCs were viable in vitro up to 70 days before senescence. There was no significant difference between the cells.
  
  
  CONCLUSIONS
  Within the limitations of this investigation, viable cells from dental pulp tissue were isolated successfully from the same donor using a minimum of 2 extracted teeth. Not all isolated cells from harvested dental pulp tissue had the characteristics of DPSCs. Post-thaw DPSCs maintained their multi-lineage differentiation capacity.
authors.affiliation: Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh, Kingdom of Saudi Arabia. E-mail. reem@ksu.edu.sa.
authors.forename: Reem S
authors.initials: RS
authors.lastname: Alsulaimani
authors.forename: Sumaiah A
authors.initials: SA
authors.lastname: Ajlan
authors.forename: Abdullah M
authors.initials: AM
authors.lastname: Aldahmash
authors.forename: May S
authors.initials: MS
authors.lastname: Alnabaheen
authors.forename: Nahid Y
authors.initials: NY
authors.lastname: Ashri
mesh_terms: D002454:Cell Differentiation; D002460:Cell Line; D015925:Cryopreservation; D003782:Dental Pulp / Q000166:cytology*; D006801:Humans; D011446:Prospective Studies; D012529:Saudi Arabia; D013234:Stem Cells / Q000166:cytology*