Chronic metabolic and induced stress impacts mesenchymal stromal cell differentiation and modulation of dental origin in-vitro

The impact of induced (smoking) and metabolic stress (diabetes) on dental stem cells with respect to pre-impact consideration on differentiation and bone formation were investigated. The progenitor stem cells isolated from dental pulp, follicle and gingival tissues were phenotyped and subjected to nicotine and high glucose stress mimicking the smoking and diabetic condition in-vitro. The results showed that the cellular viability post treatment with 100 µM nicotine and 10uM glucose was about 86% to 89% respectively in all the three cell types while about 73% in combined nicotine and glucose treatment. No variation in the expression of pro-inflammatory TNF-α, IL-1β and IL-12 in all the three cell types were noticed. The observed viability in nicotine treated cells were due to elevated IL-6, IL-10 while in glucose was due to brain derived neurotropic factor (BDNF). Higher expression of IL-4, IL-6, IL-10, TGF-β and heme oxygenase −1 (HO-1) were found high in both stressors treated cells. Differentiation and mineralization markers Alkaline phosphatase (ALP), Collagenase I (COL1), Osteocalcin, Runt related transcription factor 2 (RUNX2), Osteopontin and Bone sialoprotein were expressed in the dental pulp stem cells (DPSCs) and gingival mesenchymal stem cells (GMSCs) at varying levels post nicotine or glucose treatment while not significantly observed in dental follicular stem cells (DFSCs). Therefore, it is evident that the stem cells of varied dental origin responded to the stress are more or less uniform with physiological delay in differentiation into osteoblast. It is evident from the study that, the metabolic or induced stress subverts the process of regenerative healing by mesenchymal stromal cells with their anatomical niche.