Side population cells expressing ABCG2 in human adult dental pulp tissue

Aim  To investigate the presence of side population (SP) cells by the Hoechst exclusion method in human adult dental pulp tissue. Methodology  Human adult dental pulp-derived cells were generated from third molar teeth. The cells were stained with Hoechst 33342 and sorted into SP cells or non-SP cells [main population (MP) cells]. Both cell types were compared with cell growth and RT–PCR analyses. Results  SP cells that express ABCG2, Nestin, Notch-1 and α-smooth muscle actin were found at frequencies ranging from 0.67% to 1.02%. This SP profile disappeared in the presence of verapamil. These SP cells expressed dentine sialophosphoprotein and dentine matrix protein-1 when cultured in osteogenic medium. Conclusion  Human adult dental pulp tissue contains SP cells that differentiate into odontoblast-like cells.