Comparison of stem cell properties of cells isolated from normal and inflamed dental pulps

Aim To compare cells from normal and inflamed human dental pulps regarding the presence of stem cells, their proliferation and differentiation potential. Methodology Human dental pulp stem cells (hDPSCs) were isolated from normal (DPSC-N) and inflamed dental pulps (DPSC-I). They were compared in respect to proliferation (MTT assay), morphology and STRO-1 expression. STRO-1-positive cells were subject to proliferation (MTT and CFU counting) and morphological analyses and then submitted to odontoosteogenic, adipogenic and condrogenic differentiation. Differentiated cells were evaluated concerning morphology and the expression, by qRT-PCR, of BSP, LPL and SOX-9 genes. The amount of mineralized matrix produced after odonto-osteogenic differentiation was compared with quantitative Alizarin Red staining. Results No difference was observed in the morphology and in the proliferation rate of DPSC-N and DPSC-I either before or after separation of STRO-1-positive cells. These cells represented 0.46% (+/- 0.14) and 0.43% (+/- 0.19) of the cell population from normal and inflamed dental pulps, respectively. Both DPSC-N and DPSC-I were capable of differentiating under the three assayed conditions and presented similar patterns for BSP, LPL and SOX-9 expression. Mineralized matrix production was also compatible. In all the quantitative experiments, differences were found between cells from each patient, either from normal or from inflamed pulps. Nonetheless, there was no statistical difference between these two groups. Conclusion The morphology, proliferation rate and differentiation potential of DPSC-I were similar to the observed in DPSC-N, thus demonstrating that the inflammatory process did not affect the stem cell properties that were assessed.