REGULAR ARTICLE Chitosan as a potential osteogenic factor compared with dexamethasone in cultured macaque dental pulp stromal cells Lisa R. Amir & Dewi F. Suniarti & Sri Utami & Basril Abbas Received: 5 September 2013 /Accepted: 3 June 2014 /Published online: 4 July 2014 # Springer-Verlag Berlin Heidelberg 2014 Abstract Chitosan, a natural biopolymer derived from chitin, is considered a promising scaffold material for bone tissue engineering. The ability of chitosan to promote the osteogenic differentiation of dental pulp stromal/stem cells (DPSCs) is unknown. We have evaluated the potential of chitosan to induce the osteogenic differentiation of macaque DPSCs in comparison with that of dexamethasone. DPSCs were cultured in mineralizing medium supplemented with 5 or 10 μg/ml chitosan or with 1 or 10 nM dexamethasone. The metabolic activity of DPSCs was measured by MTT assay. Their osteo- genic differentiation was determined by the number of tran- scripts of RUNX2, alkaline phosphatase (ALP), and COL1A1 by using real-time polymerase chain reaction, by alizarin red staining for mineral deposition, and by the ALP activity re- leased into the medium for their ability to support biomineralizaton. Addition of chitosan to the mineralizing medium significantly increased DPSCs metabolism after 7 and 14 days of culture (P ≤ 0.0001). Chitosan at 5 μg/ml also significantly enhanced RUNX2 and ALP mRNA but not COL1A1 mRNA; chitosan tended to increase the release of ALP hydrolytic enzyme activity into the medium during the first week. Dexamethasone upregulated the osteogenic markers tested. Mineral deposition was similar in the chitosan and dexamethasone groups and was not statistically different from that of the mineralizing control group. Thus, the potential of chitosan to stimulate DPSCs proliferation and early osteo- genic differentiation is comparable with that of dexametha- sone, but mineralization remains unaffected by chitosan treat- ment. In addition to its role as a three-dimensional scaffold for osteogenic cells in vivo, chitosan might also stimulate DPSCs proliferation and early osteogenic differentiation in vitro. Keywords Chitosan . Dexamethasone . Dental pulp stromal cells . Osteogenic supplement . Macaque Introduction Tissue engineering is currently being developed to treat large bone defects. The technique involves the seeding of progenitor cells onto a scaffold material that serves as a temporary extra- cellular matrix to facilitate attachment, proliferation, and differ- entiation of the cells to form the desired tissues (Howard et al. 2008). The ideal scaffold should be biocompatible, biodegrad- able at a similar rate to new tissue formation and should mimic the natural environment of the tissue in vivo (Yang et al. 2001; Sachlos and Czernuszka 2003). Chitosan is now being actively investigated as a promising natural biopolymer scaffold mate- rial (Lee et al. 2000; Seol et al. 2004; Cho et al. 2004). Chitosan is a partially deacetylated form of chitin, a polysaccharide that biomineralizes and forms the shell of crustaceans. It appears to be biocompatible and is degraded by enzymes into oligosaccharides that are rapidly resorbed. It forms an insoluble complex with connective tissue molecules such as collagen and glycosaminoglycans to form a porous interconnected three-dimensional (3D) structure, making this biomolecule attractive as a scaffolding material for tissue engineering purposes (Mi et al. 2006; Yamada et al. 2007). Chitosan is highly versatile and useful for a wide range of applications: as injectable particles in solution, as solid porous This study was financially supported by a Universitas Indonesia Research Excellence Grant (DRPM/RUUI Unggulan/2010/I/4150). L. R. Amir (*) : D. F. Suniarti : S. Utami Department of Oral Biology, Faculty of Dentistry, Universitas Indonesia, Salemba Raya No.4, Jakarta Pusat 10430, Indonesia e-mail: lisa.amir@gmail.com L. R. Amir e-mail: lisa.amir@ui.ac.id B. Abbas Center for Application of Isotope and Radiation Technology, National Atomic Energy Agency, Jakarta, Indonesia Cell Tissue Res (2014) 358:407–415 DOI 10.1007/s00441-014-1938-1