Figure 1. Differentiation of hDPSCs. (A–C) In vitro differentiation of hDPSCs. hDPSCs collected at the crown- (DP1) and root-completed (DP75) stages were cultured and then tested for their ability to differentiate into cells of multiple lineages. Cell morphology of DP1 cells after 5 days in culture is shown in (A). Osteogenesis was assessed by ALP-activity staining (B) and with von Kossa stain (C). Scale bar = 200 µm (A–C). (D–I) Characterization of hDPSCs (crown-completed stage [DP1] and root-formative stage [DP27]) transplanted into NOD-SCID mice for assessment of differentiation in vivo. DP1 (D–F) and DP27 (G–I) cells were seeded onto calcium-phosphate scaffolds and transplanted subcutaneously into NOD-SCID mice. Tissues were isolated at 15 wks post-transplantation and stained with hematoxylin and eosin (D,E,G,H) or with von Kossa (F,I) stain. Polarized light demonstrates alignment of the collagen fibers on the forming surfaces (E,H). In the hDPSC transplants, the scaffolds (Sc) are lined with a dentin-like matrix (d) surrounding connective tissue (CT). Arrows show the calcified matrix (F,I). Scale bar = 500 µm (D–I).