الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Mesenchymal stem cells (MSCs) with a capacity of self-renewal and multi-lineage differentiation have attracted worldwide attention during the past decade as progenitor cell source for tissue engineering and regeneration. MSCs were first identified in aspirates of adult bone marrow. They developed clonogenic clusters of adherent fibroblastic colony-forming units with the potential to undergo extensive proliferation in vitro and to differentiate into different stromal cell lineages. Since then, bone marrow was the most utilized source of MSCs; however, there was a need to isolate MSCs from accessible tissues with less surgical trauma. Recently, stem cells from dental tissues have provided that alternate source of MSCs with characterization of stem cells within the dental pulp stem cells (DPSCs), periodontal ligament stem cells (PDLSCs), stem cells from human exfoliated deciduous teeth (SHED), dental follicle progenitor cells (DFPCs), stem cells from apical papilla (SCAP), oral periosteum stem cells (OPSCs) and recently from gingival connective tissue (GMSCs), however there is still limited evidence regarding the capacity of dental MSCs for bone regeneration.
The aim of this work was to study and compare the proliferation capacity, osteoblastic differentiation and osteogenic activity of the gingival stem cells and pulpal stem cells on induction of cellular proliferation and osteogenic differentiation via StemXVivo R and D System. This was assessed through evaluation of osteogenic activity of osteoblasts through gene expression of ALP and osteocalcin as well as evaluation of osteoblastic activity during mineralization.
Identification of stem cells was performed through the expression of surface markers CD90 and CD105 as well as lack of expression of CD 45 (phenotype verification). This was analyzed by flow cytometry. The proliferation capacity of the cells was measured by ELISA reader. Evaluation of alkaline phosphatase enzyme activity and genetic expression of osteocalcin were done using quantitative real time PCR. Moreover, histological examination of extracellular mineralization by the inverted microscope was performed using Alizarin red staining (functional verification). Finally all the results were subjected to statistical analysis and interpretation by ANOVA test.
This study was carried out on extracted human third molars and/or premolars from which pulpal tissue and gingival tissue were obtained and separated into two groups, pulpal group and gingival group. The human MSCs used in this study were derived from the dental pulp (hDPSCs) and gingival tissue (hGMSCs) of those normal sound impacted third molars and/or premolars extracted for orthodontic purposes. Each sample of hDPSCs and hGMSCs was obtained from the same donor. Fourteen adult donors aged 18-25 years participated in the research work. All donors were healthy, free from systemic diseases, taking no medications, non-alcoholic and non-smokers. They were recruited among the patients referred to the dental clinics of the Faculty of Dentistry, Cairo University.
The primary outcome (proliferation capacity) of the present study showed the highest mean value recorded in undifferentiated dental pulp MSCs, followed by osteogenic differentiated dental pulp MSCs, then undifferentiated gingival MSCs, while the lowest mean value was recorded in osteogenic differentiated gingival MSCs. ANOVA test revealed that the difference between all groups was extremely statistically significant (p<0.0001). ). Tukey’s post hoc test revealed no significant difference between osteogenic differentiated pulp MSCs and undifferentiated gingival MSCs
Regarding the secondary outcomes (ALP and osteocalcin gene expression) , the highest mean value was recorded in osteogenic differentiated pulp MSCs, followed by osteogenic differentiated gingival MSCs, while undifferentiated pulp and gingival MSCs cells recorded a value of (0.0001). ANOVA test revealed that the difference between all groups was extremely statistically significant (p<0.0001). Tukey’s post hoc test revealed a significant difference between osteogenic differentiated pulp MSCs and osteogenic differentiated gingival MSCs. Moreover, the differentiated cells recorded a significantly higher mean value compared to the undifferentiated MSCs. In addition, staining observations of Alizarin red after 21 days of induction showed that the accumulations of calcium deposits in cultures of DPSCs were much higher than GMSCs.