title: Human periodontal ligament: a niche of neural crest stem cells.
abstract: OBJECTIVE
  The periodontal ligament is a specialized connective tissue, derived from dental follicle and originated from neural crest cells. Recently it has been suggested, based on animal models, that periodontal ligament could be a niche for neural crest stem cells. However, there is still little knowledge on this subject. The identification of neural crest adult stem cells has received much attention based on its potential in tissue regeneration. The objective of the present work was to verify the human periodontal ligament as a niche for neural crest stem cells.
  
  
  METHODS
  Cells from human periodontal ligament were isolated from 10 teeth of seven individuals (periodontal ligament pool group) and also from four teeth of one individual (periodontal ligament single group), after enzymatic digestion. The cells were cultured in specific inductive medium. Analyses of protein and gene expression were performed through immunocytochemistry and reverse transcription-polymerase chain reaction techniques, respectively.
  
  
  RESULTS
  Mesodermal phenotypes (adipogeneic, osteogenic and myofibroblastic) were identified after culture in inductive medium. Immunocytochemistry analyses showed the presence of the nestin marker of neural stem cells and also markers of undifferentiated neural crest cells (HNK1, p75). When cultured in inductive medium that allowed neural differentiation, the cells showed markers for beta-tubulin III, neurofilament M, peripherin, microtubule-associated protein 2 and protein zero. The results were similar between the two study groups (the periodontal ligament pool group and the periodontal ligament single group).
  
  
  CONCLUSIONS
  This research provides evidence that human periodontal ligament, in addition to its mesodermal derivatives, produces neural crest-like cells. Such features suggest a recapitulation of their embryonic state. The human periodontal ligament revealed itself as a viable alternative source for possible primitive precursors to be used in stem-cell therapies.
authors.affiliation: Departamento de Estomatologia, Centro de Ciências da Saúde, Universidade Federal de Santa Catarina, Brazil. gustavocoura@hotmail.com
authors.forename: G S
authors.initials: GS
authors.lastname: Coura
authors.forename: R C
authors.initials: RC
authors.lastname: Garcez
authors.forename: C B N Mendes
authors.initials: CB
authors.lastname: de Aguiar
authors.forename: M
authors.initials: M
authors.lastname: Alvarez-Silva
authors.forename: R S
authors.initials: RS
authors.lastname: Magini
authors.forename: A G
authors.initials: AG
authors.lastname: Trentin
mesh_terms: D000293:Adolescent; D000328:Adult; D053687:Adult Stem Cells; D018959:CD57 Antigens / Q000032:analysis; D019070:Cell Lineage; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000032:analysis; D008562:Membrane Glycoproteins / Q000032:analysis; D008869:Microtubule-Associated Proteins / Q000032:analysis; D018993:Myelin P0 Protein / Q000032:analysis; D009419:Nerve Tissue Proteins / Q000032:analysis; D064231:Nestin; D009432:Neural Crest / Q000166:cytology*; D016900:Neurofilament Proteins / Q000032:analysis; D010513:Periodontal Ligament / Q000737:chemistry / Q000166:cytology*; D064531:Peripherins; D014404:Tubulin / Q000032:analysis; D055815:Young Adult
chemical_list: D018959:CD57 Antigens; D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; D008869:Microtubule-Associated Proteins; D018993:Myelin P0 Protein; C577484:NES protein, human; D009419:Nerve Tissue Proteins; D064231:Nestin; D016900:Neurofilament Proteins; C578994:PRPH protein, human; D064531:Peripherins; D014404:Tubulin; C061195:neurofilament protein M