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 alpha-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.