title: Effects of In Vitro Osteogenic Induction on In Vivo Tissue Regeneration by Dental Pulp and Periodontal Ligament Stem Cells.
abstract: BACKGROUND
  The aim of this study was to determine the effects of in vitro odontogenic/cementogenic differentiation on the in vivo tissue regeneration of dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs).
  
  
  METHODS
  DPSCs and PDLSCs were predifferentiated for 0, 4, or 8 days with an odontogenic/cementogenic medium and then transplanted into subcutaneous pockets in immunocompromised mice. The transplants were harvested 9 weeks after transplantation, and the characteristics of the newly formed tissues in vivo were analyzed by histologic staining; examining alkaline phosphate activity; immunohistochemical staining for osteocalcin, dentin sialoprotein, and type XII collagen; and quantitative real-time polymerase chain reaction to analyze the expression patterns of the following genes: RUNX2, OC, DMP1, DSPP, POSTN, CP23, and Col XII.
  
  
  RESULTS
  In DPSC transplants, the amount of new tissues was similar in all groups, whereas in predifferentiated transplants the OC and DSPP expression were higher than undifferentiated transplants. Predifferentiated PDLSC transplants generated more hard tissue and expressed higher alkaline phosphatase activity than undifferentiated transplants. In particular, 8-day predifferentiated PDLSC transplants formed tissue closer to the cementum/PDL complex in vivo as confirmed by the higher expression levels of POSTN, CP23, and Col XII.
  
  
  CONCLUSIONS
  Although there was no significant increase in tissue-forming ability among DPSCs after predifferentiation, predifferentiated DPSCs generated hard tissue closer to dentin. Also, predifferentiated PDLSCs appeared to be able to generate higher-quality and greater amounts of tissue for dental regeneration than undifferentiated PDLSCs.
authors.affiliation: Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Yoonsun
authors.initials: Y
authors.lastname: Cha
authors.affiliation: Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Mijeong
authors.initials: M
authors.lastname: Jeon
authors.affiliation: Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Korea; Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Hyo-Seol
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Korea; Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Seunghye
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Korea; Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Seong-Oh
authors.initials: SO
authors.lastname: Kim
authors.affiliation: Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Korea; Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Jae-Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul, Korea; Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea. Electronic address: songjs@yuhs.ac.
authors.forename: Je Seon
authors.initials: JS
authors.lastname: Song
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D025021:Cementogenesis; D002648:Child; D003782:Dental Pulp / Q000166:cytology*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D009805:Odontogenesis; D010012:Osteogenesis; D010513:Periodontal Ligament / Q000166:cytology*; D012038:Regeneration; D013234:Stem Cells / Q000166:cytology*; D055815:Young Adult
keywords: Dental pulp stem cell; periodontal ligament stem cell; predifferentiation; regeneration