Human periodontal ligament: a niche of neural crest stem cells G. S. Coura 1,2 , R. C. Garcez 2 , C. B. N. Mendes de Aguiar 2 , M. Alvarez-Silva 2 , R. S. Magini 1 , A. G. Trentin 2 1 Departamento de Estomatologia, Centro de CiÞncias da Safflde, Universidade Federal de Santa Catarina, Brazil and 2 Departamento de Biologia Celular, Embriologia e GenØtica, Centro de CiÞncias Biológicas, Universidade Federal de Santa Catarina, Brazil The periodontal ligamentis a special- ized, vascular and highly cellular con- nective tissue that plays an important role in supporting tooth function, maintaining homeostasis and repairing tissue damage caused by periodontal disease or mechanical trauma (1). Periodontal ligament tissue originates from neural crest-derived ectomesenc- hyme (2,3) and contains a heteroge- neous population of cells, including periodontal fibroblasts, cementoblasts, osteoblasts, endothelial cells and epi- thelial cells (4). Recently, it has been suggested that human periodontal lig- ament contains mesenchymal stem cells (5). In addition, multipotent stem cells with mesodermal and neural potenti- ality have been identified in rat and human periodontal ligament (6,7). However, the mechanisms that regu- late the development of periodontal ligament lineages have not been fully elucidated (6). Periodontal diseases are Coura GS, Garcez RC, Mendes de Aguiar CBN, Alvarez-Silva M, Magini RS, Trentin AG. Human periodontal ligament: a niche of neural crest stem cells. J Periodont Res 2008; 43: 531–536. Ó 2008 The Authors. Journal compilation Ó 2008 Blackwell Munksgaard Background and 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. Material and 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 b-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). Conclusion: This research provides evidence that human periodontal ligament, in addition to its mesodermal derivatives, produces neural crest-like cells. Such fea- tures suggest a recapitulation of their embryonic state. The human periodontal ligament revealed itself as a viable alternative source for possible primitive pre- cursors to be used in stem-cell therapies. Gustavo dos Santos Coura, Laboratório de Neurobiologia e Hematologia Celular e Molecular, Departamento de Biologia Celular, Embriologia e GenØtica, Centro de CiÞncias Biológicas, Universidade Federal de Santa Catarina, Campus Universitµrio, Trindade, CEP 88040-900, Florianópolis, SC, Brazil Tel: +55 48 3721 6905 Fax: +55 48 3721 5148 e-mail: gustavocoura@hotmail.com Key words: neural crest; periodontal ligament; stem cell; cell culture Accepted for publication November 1, 2007 J Periodont Res 2008; 43: 531–536 All rights reserved Ó 2008 The Authors. Journal compilation Ó 2008 Blackwell Munksgaard JOURNAL OF PERIODONTAL RESEARCH doi:10.1111/j.1600-0765.2007.01065.x