Evaluation of immunophenotyping, proliferation and osteogenic differentiation potential of SSEA-4 positive stem cells derived from pulp of deciduous teeth.

OBJECTIVES: Despite the increased interest in stem cells isolated from remnant pulp of deciduous teeth, no specific marker has been yet established for them. The present study aimed to investigate whether SSEA-4 (stage-specific embryonic antigen) would be a suitable marker to isolate stem cells from Human Exfoliated Deciduous teeth (SHEDs) in order to increase its differentiation potential toward osseous tissue.

DESIGN: The SHEDs were isolated and the expression patterns of mesenchymal, hematopoietic and embryonic stem cell markers were assessed. The cells were then divided into two groups of SSEA-4(+) and unsorted SHEDs and the cell proliferation rate and population-doubling-time (PDT) were calculated. Subsequently, the differentiation potentials were examined through alizarin-red staining and Quantitative real time-PCR (qRT-PCR).

RESULTS: Isolated cells were spindle-shaped with a high expression of mesenchymal stem cell markers and weak expression of hematopoietic markers. The mean expression of Oct-4 was 68.77%±1.28. Despite similar proliferation rates between SSEA-4(+) and unsorted SHEDs, because of differences in the shape of the growth curves, PDT was lower in unsorted SHEDs (P = 0.2 × 10-4 ). Alizarin-red staining showed similar calcium deposition in both groups. Upon differentiation, the expression of osteocalcin was higher in unsorted SHEDs (P = 0.043), while, the expression of alkaline phosphatase was lower (P<0.001). The parathyroid hormone receptor (PTHR) expression was not significantly different (P = 0.0625).

CONCLUSIONS: The results of the present study revealed that SHEDs have high differentiation potentials even in the unsorted cells. Although the SSEA-4-positive SHEDs showed slightly better osteogenic potential, the differences were not abundant to link SSEA-4 expression with superior differentiation potency.