REGULAR ARTICLE Osteogenic differentiation of stem cells derived from human periodontal ligaments and pulp of human exfoliated deciduous teeth Kiranmai Chadipiralla & Ji Min Yochim & Bindu Bahuleyan & Chun-Yuh Charles Huang & Franklin Garcia-Godoy & Peter E. Murray & Eric J. Stelnicki Received: 19 October 2009 / Accepted: 23 February 2010 / Published online: 23 March 2010 # Springer-Verlag 2010 Abstract Multipotent stem cells derived from periodontal ligaments (PDLSC) and pulp of human exfoliated deciduous teeth (SHED) represent promising cell sources for bone regeneration. Recent studies have demonstrated that retinoic acid (RA) and dexamethasone (Dex) induce osteogenesis of postnatal stem cells. The objective of this study was to examine the effects of RA and Dex on the proliferation and osteogenic differentiation of SHED and PDLSC and to compare the osteogenic characteristics of SHED and PDLSC under RA treatment. SHED and PDLSC were treated with serum-free medium either alone or supplemented with RA or Dex for 21 days. The proliferation of SHED and PDLSC was significantly inhibited by both RA and Dex. RA significantly upregulated gene expression and the activity of alkaline phosphatase in SHED and PDLSC. Positive Alizarin red and von Kossa staining of calcium deposi- tion was seen on the RA-treated SHED and PDLSC after 21 days of culture. The influences of RA on the osteogenic differentiation of SHED and PDLSC were significantly stronger than with Dex. Supplemention with insulin enhanced RA-induced osteogenic differentiation of SHED. Thus, RA is an effective inducer of osteogenic differentiation of SHED and PDLSC, whereas RA treatment in combination with insulin supplementation might be a better option for inducing osteogenic differentiation. Significantly higher cell proliferation of PDLSC results in greater calcium deposition after 3-week culture, suggesting that PDLSC is a better osteogenic stem cell source. This study provides valuable information for efficiently producing osteogenically differentiated SHED or PDLSC for in vivo bone regeneration. Keywords Adult stem cells . Osteogenesis . Dental pulp . Periodontal ligament . Retinoic acid . Human Introduction Multipotent postnatal stem cells have been isolated from various types of tissues, e.g., bone marrow, adipose tissue, muscle, periosteum, synovial tissue, dental pulp, and periodontal ligaments (Campagnoli et al. 2001; This work was supported by the President’ s Faculty Research and Development Grant from Nova Southeastern University and the Craniofacial Research Grant from Joe DiMaggio Children’ s Hospital. P. E. Murray Department of Endodontics, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, Fla., USA C.-Y. C. Huang (*) Department of Biomedical Engineering, University of Miami, 219A McArthur Annex, 1251 Memorial Drive, Coral Gables FL 33146, USA e-mail: c.huang@miami.edu F. Garcia-Godoy Bioscience Research Center, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tenn., USA K. Chadipiralla : J. M. Yochim : B. Bahuleyan : C.-Y. C. Huang : E. J. Stelnicki Craniofacial Research Laboratory, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, Fla., USA E. J. Stelnicki Cleft and Craniofacial Center, Joe DiMaggio Children’ s Hospital, Hollywood, Fla., USA Cell Tissue Res (2010) 340:323–333 DOI 10.1007/s00441-010-0953-0