In Vitro Characterization of Stem Cells from Human Exfoliated Deciduous Teeth (SHED)

Abstract

Stem cells from human exfoliated deciduous teeth (SHED) provide a new attractive source for stem cells; in this study we further characterize SHED. SHED were isolated, differentiated using osteogenic/ odontogenic differentiation media, characterized using light microscope, SEM and immunocytochemistry using CD44. Also, Immunohistochemistry using CD44 was performed on extirpated pulp tissues. We found that a naturally exfoliated human tooth contains a population of stem cells that attain morphological homogeneity after the first passage, on adding the osteogenic/odontogenic medium, sporadic noduleshaped structures were observed after two weeks that were positively stained with alizarin red and von Kossa stains. SHED stained with H& E showed a basophilic, eccentric nucleus with an eosinophilic cytoplasm in which two differently stained areas were clearly distinguishable. Also we found using SEM that SHED spread on the UBM scaffolds surfaces showing multiple filopodia and formed collagen-like structures by the seventh day. After three weeks, seeded scaffolds incubated in osteogenic/odontogenic media showed many mineralized nodules in the ECM. Cultured SHED revealed positive immunoreactivity when treated with CD44. Also, sections of pulp tissue treated with CD44 depict positively stained cells situated mainly in the perivascular areas reinforcing the hypothesis that pericytes may be the origin of SHED.