Human Dental Pulp Mesenchymal Cells Research Articles

In Vitro Biocompatibility Evaluation of a New Co-Cr-B Alloy with Potential Biomedical Application

Cobalt–chromium (Co-Cr) alloys have been used in a wide variety of biomedical applications, including dental, cardiovascular, and orthopedic devices. In vitro studies have shown that the mineralization of cells involved in osteogenesis is regulated by boron. The development of a new cobalt-chromium-boron (Co-Cr-B) alloy improves the mechanical properties of the metal, such as wear resistance, and meets biocompatibility requirements. Therefore, the objective of this study was to evaluate the osteogenic differentiation and biocompatibility in in vitro assays. Human dental pulp mesenchymal cells (hDPSCs) were isolated from volunteers and then co-cultured with the Co-Cr plus boron alloy from 0.3% to 1% for 15 days, while the formation of calcium deposits was quantified by Alizarin red staining and the expression of genes was related to osteodifferentiation by RT-qPCR. Simultaneously, the cytotoxicity of our alloy was evaluated by MTT assay and the change in the gene expression of cytokines commonly associated with inflammatory processes. The results showed low cytotoxicity when cells were treated with the Co-Cr-B alloy, and no change in the gene expression of IL-1β, TNF-α, IL-6, and IL-8 was observed compared to the untreated control (p > 0.05). The osteoinduction results shown an increase in mineralization in hDPSCs treated with Co-Cr-B alloy with 1.0% B. In addition, a significant increase in mRNA levels for collagen type 1 in with 0.3% boron and alkaline phosphatase and Runx2 with 0.6% boron were observed. The addition of Boron to the ASTM F75 Co-Cr base alloy improves the biocompatible characteristics. No cytotoxicity and any change of the expression of the pro-inflammatory cytokines IL-1β, TNF-α, IL-6, and IL-8 in human peripheral blood mononuclear cells treated with the cobalt-chromium-boron alloy was observed in vitro assays. Furthermore, our alloy acts as an osteoinductive in osteogenic differentiation in vitro. Therefore, our results could set the standard for the development of in vivo trials and in the future, it could be considered as an alternative for regenerative therapy.

Cytotoxicity and Effects of a New Cacium Hydroxide Nanoparticle Material on Production of Reactive Oxygen Species by LPS-Stimulated Dental Pulp Cells.

The aim of this study was to synthesize and characterize calcium hydroxide (CH) nanoparticles [CH-NP] and compare the cytotoxicity of these materials with that of mineral trioxide aggregate (White MTA) in human dental pulp mesenchymal cells (hDPMCs) stimulated by lipopolysaccharide (LPS). The CH-NP were synthesized by the co-precipitation method, and the physical properties were investigated through X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS). LPS-stimulated hDPMCs were placed in contact with different dilutions of culture media previously exposed to CH-NP and white MTA for 24 h. The groups were tested for cell viability by MTT formazan and Alamar Blue assays, the production of nitric oxide (NO) by Griess method and the production of reactive oxygen species (ROS) by means of the fluorescent oxidant-sensing probe 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). Control groups for viability test were maintained in DMEM (not LPS-stimulated). For NO and ROS production, negative control group was cells in DMEM, and positive control was cells stimulated by LPS. The results were statistically analyzed by two-way ANOVA, Tukey's test and Dunnett's test (ɑ=0.05). The results showed that the cell viability remained above 50% in all materials, independent of the dilution in MTT formazan and Alamar Blue tests. MTA showed a reduction in NO production at dilutions of 1:4 to 1:32 compared with the positive control group (P<0.05). The tested materials exhibited lower ROS production by DPMCs than that by cells in the positive control group (P<0.05), and similar ROS production to the negative control group (P>0.05). The outcomes of present in vitro study showed that MTA and [CH-NP] were not cytotoxic materials, with MTA closer to the results of control group (DMEM). MTA and [CH-NP] reduced ROS production at basal levels, with MTA inhibiting NO production at higher dilutions.

Scaling-Up of Human Dental Pulp Mesenchymal Cells on Primary Culture

Introduction: Tissue Engineering (TE) aims to bio manufacture human tissues, an endeavor that requires a large number of cells, preferably autologous ones. Typically, an autologous cell source is unable to provide the required amount of cells and it is necessary that such cells be cultured during a prolonged period of time. One of the methodologies used to obtain and expand autologous cells in culture is explants; however, explants are commonly discarded at the moment of the first cell passage. Given the difficulty in obtaining those cell sources, a good alternative would be to reuse the explants and put them back into culture after cell passage. Nevertheless, various modifications have been seen in long-term cell culture, such as modifications of gene expression, and number and amount of proteins. Objective: To evaluate changes in gene expression of extracellular matrix (ECM) and adhesion molecules (AM) in human mesenchymal dental pulp progenitor cells (hMDPC) culture of reused explants. Methods: Gene expression of cells derived from second passage reused explants culture was accessed by Real Time PCR array of Human ECM and AM. Results: Twenty-nine genes showed at least a 5-fold change increase or decrease compared to the control group. Conclusion: Long-term culture frequently induces gene expression changes in ECM or AM. Re using explants is an option to expand the cell source in order to decrease culture time. However, it is necessary to understand, map and control those changes in order to ensure clinical application safety.