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To assess the pro-angiogenic and pro-inflammatory capacity of the dentine-pulp complex in response to the prolyl hydroxylase inhibitor L-mimosine in a tooth slice organ culture model.Human teeth were sectioned transversely into 600-μm-thick slices and cultured in medium supplemented with serum and antibiotics. Then, pulps were stimulated for 48 h with L-mimosine. Pulps were subjected to viability measurements based on formazan formation in MTT assays. In addition, histological evaluation of pulps was performed based on haematoxylin and eosin staining. Culture supernatants were subjected to immunoassays for vascular endothelial growth factor (VEGF) to determine the pro-angiogenic capacity and to immunoassays for interleukin (IL)-6 and IL-8 to assess the pro-inflammatory response. Interleukin-1 served as pro-inflammatory control. Echinomycin was used to inhibit hypoxia-inducible factor-1 (HIF-1) alpha activity. Data were analysed using Student's t-test and Mann-Whitney U test.Pulps within tooth slices remained vital upon L-mimosine stimulation as indicated by formazan formation and histological evaluation. L-mimosine increased VEGF production when normalized to formazan formation in the pulp tissue of the tooth slices (P 0.05). This effect on VEGF was reduced by echinomycin (P 0.01). Changes in normalized IL-6 and IL-8 levels upon treatment with L-mimosine did not reach the level of significance (P 0.05), whilst treatment with IL-1, which served as positive control, increased IL-6 (P 0.05) and IL-8 levels (P 0.05).The prolyl hydroxylase inhibitor L-mimosine increased VEGF production via HIF-1 alpha in the tooth slice organ culture model whilst inducing no prominent increase in IL-6 and IL-8. Pre-clinical studies will reveal if these in vitro effects translate into dental pulp regeneration.

To establish a method for characterization of the nanoparticle-cell interaction without labeling, the changes in granularity of Caco-2 cells due to association of biomimetic nanoparticles, consisting of PLGA and wheat germ agglutinin (WGA), were monitored by side scattering using flow cytometry. The reliability was confirmed by a temperature-dependent linear correlation between side scatter data and cell-associated fluorescence intensities of cells loaded with fluorescent biomimetic nanoparticles. Moreover, not only the binding to but also the uptake of the nanoparticles into the cells was detected. Whereas the cell-binding of nanoparticles with lowest WGA-densities was controlled by temperature-dependent diffusional processes, the cytoinvasive properties of the WGA-corona prevailed at higher lectin densities. Due to the multiparametric character of the flow cytometric analysis useful additional information on the viability and agglomeration of cells is provided at the same time.