ascorbic-acid and potassium-phosphate

The aim of this study was to investigate the effects of HEMA and TEGDMA on the odontogenic differentiation potential of dental pulp stem/progenitor cells.. Dental stem/progenitor cell cultures were established from pulp biopsies of human deciduous teeth of 1-3 year-old children (Deciduous Teeth Stem Cells-DTSCs). Cultures were characterized for stem cell markers, including STRO-1, CD146, CD34, CD45 using flow cytometry. Cytotoxicity was evaluated with the MTT assay. DTSCs were then induced for osteo/odontogenic differentiation by media containing dexamethasone, KH(2)PO(4),β-glycerophosphate and L-ascorbic acid phosphate in the presence of nontoxic concentrations of HEMA (0.05-0.5mM) and TEGDMA (0.05-0.25mM) for 3 weeks. Additionally, the effects of a single exposure (72 h) to higher concentrations of HEMA (2mM) and TEGDMA (1mM) were also evaluated.. DTSCs cultures were positive for STRO-1 (7.53±2.5%), CD146 (91.79±5.41%), CD34 (11.87±3.02%) and negative for CD45. In the absence of monomers cell migration, differentiation and production of mineralized dentin-like structures could be observed. Cells also progressively expressed differentiation markers, including dentin sialophosphoprotein-DSPP, bone sialoprotein-BSP, osteocalcin-OCN and alkaline phosphatase-ALP. On the contrary, long-term exposure to nontoxic concentrations of HEMA and TEGDMA significantly delayed the differentiation and mineralization processes of DTSCs, whereas, one time exposure to higher concentrations of these monomers almost completed inhibited mineral nodule formation. BSP, OCN, ALP and DSPP expression were also significantly down-regulated.. These findings suggest that HEMA and TEGDMA can severely disturb the odontogenic differentiation potential of pulp stem/progenitor cells, which might have significant consequences for pulp tissue homeostasis and repair.

Topics: Alkaline Phosphatase; Antigens, CD34; Antigens, Surface; Ascorbic Acid; Biomarkers; Calcification, Physiologic; CD146 Antigen; Cell Differentiation; Cell Movement; Cells, Cultured; Child, Preschool; Dental Pulp; Dexamethasone; Down-Regulation; Extracellular Matrix Proteins; Glucocorticoids; Glycerophosphates; Humans; Infant; Integrin-Binding Sialoprotein; Leukocyte Common Antigens; Methacrylates; Odontogenesis; Osteocalcin; Phosphates; Phosphoproteins; Polyethylene Glycols; Polymethacrylic Acids; Potassium Compounds; Sialoglycoproteins; Stem Cells; Tooth, Deciduous

We evaluated the interaction between ascorbic acid (AA) and (+)-catechin (CTCH) in potassium phosphate solution, pH 7.4 (PPS) and in human plasma. In both systems, the oxidation was started by adding 2,2'-azobis-(2-amidinopropane) clorhidrate (AAPH). The concentrations of AA and CTCH were determined by HPLC using electrochemical detection. In PPS, CTCH was oxidized by AAPH (50 mM), in either the absence or presence of different initial concentrations of AA (25-200 microM). In the presence of AA, CTCH depletion was delayed, an effect that was dependent upon the initial concentration of AA. When 100 microM AA was added after the oxidation had begun, CTCH depletion was arrested for 30 min. The kinetics of AA oxidation by AAPH was also characterized in PPS. AA (100 microM) was completely consumed after 60 min of reaction at 37 degrees C, in both the absence and presence of 100 mM CTCH. When human plasma was incubated with 50 mM AAPH in the absence of added CTCH, AA was completely consumed after 45-60 min. CTCH did not prevent AA depletion in human plasma at the concentrations tested (10, 50 100 microM). The results point out that AA is able to protect other aqueous soluble antioxidants, e.g.: CTCH.

Topics: Amidines; Antioxidants; Ascorbic Acid; Catechin; Chromatography, High Pressure Liquid; Drug Interactions; Humans; Kinetics; Oxidants; Phosphates; Plasma; Potassium Compounds; Time Factors