Mixed and Purified SCAPs: Similar Growth, Phenotypic and Differentiation Characteristics


Dr. Benjamin D. Zeitlin: 0000-0003-0110-0188


Biomedical Sciences

Document Type

Conference Presentation

Conference Title

General Session & Exhibition of the IADR


International Association for Dental Research


San Francisco, CA

Date of Presentation



Objective: To compare the phenotype, the growth curve and the osteo- and chondrogenic differentiation potential of mixed vs purified stem cells populations from the apical papilla (SCAPs); gingival fibroblasts (GFs) were used as control. Method: Four cell populations were considered: 1)mixed SCAPs (M-SCAPs); 2&3)SCAPs purified by immunomagnetic separation based either on Stro-1 (P-SCAPs1), or on a combination of CD73, CD90 and CD105 (P-SCAPs2); 4)gingival fibroblasts (GFs). Each population was subcultured, and their growth curve determined. Their phenotype was characterized by flow cytometry using antibodies against CD29, CD31, CD34, CD90, CD105 and Stro-1. The cells were then cultured in osteo- and chondrogenic media during 25 days. Osteogenic and chondrogenic differentiation were evaluated respectively by alizarin red S and alcian blue staining. Result: All four cell populations had similar growth curves, were homogeneously positive to CD29, CD90 and CD105 (percentage of positive cells >97% in all cases but P-SCAPs1 for CD90 – 91.5%), and negative to CD31, CD34 and Stro-1 (<3% in all cases but GFs for CD34 – 7.5%). All cell populations were positive for alizarin red S, and all but GFs were positive for alcian blue. Conclusion: The present results question the specificity of certain markers considered to identify dental mesenchymal stem cells. The expression of Stro-1 was notably lost in P-SCAPs1, which however conserved their multi-differentiation potential. The rationale of sorting cells based on these markers is therefore called into question vs using a mixed population. Finally, the results suggest that GFs either contain a certain proportion of osteogenic progenitor cells, or that they intrinsically possess an osteogenic differentiation potential.