22 research outputs found
Polymerization shrinkage kinetics of dimethacrylate resin-cements
info:eu-repo/semantics/publishe
Setting kinetics and shrinkage of self-adhesive resin cements depend on cure-mode and temperature
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The proliferation and differentiation of osteoblasts in co-culture with human umbilical vein endothelial cells: An improved analysis using fluorescence-activated cell sorting
The interaction of osteoblasts and endothelial cells plays a pivotal role in osteogenesis. This interaction has been extensively studied using their direct co-culture in vitro. However, co-culture experiments require clear discrimination between the two different cell types in the mixture, but this was rarely achieved. This study is the first to use fluorescence-activated cell sorting (FACS) for the separation and quantitative analysis of the proliferation and differentiation of MG-63 cells grown in direct co-culture with human umbilical vein endothelial cells (HUVECs). The cells of the MG-63 cell line have properties consistent with the characteristics of normal osteoblasts. We labeled HUVECs with fluorescent antibody against CD31 and used FACS to measure the proportions of each cell type and to separate them based on their different fluorescence intensities. The rate of proliferation of the MG-63 cells was estimated based on a count of the total viable cells and the proportion of MG-63 cells in the mixture. The mRNA expression levels of the osteoblast differentiation markers alkaline phosphatase (ALP), collagen type 1 (Coll-1) and osteocalcin (OC) in the MG-63 cells were measured via real-time PCR after the separation via FACS. We found that HUVECs stimulated the proliferation of the MG-63 cells after 72 h of co-culture, and inhibited it after 120 h of co-culture. The mRNA expression levels of ALP and Coll-1 significantly increased, whereas that of OC significantly decreased in MG-63 after co-culture with HUVECs. Using FACS for the quantitative analysis of the proliferation and differentiation of osteoblasts directly interacting with endothelial cells could have merit for further co-culture research
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Osteogenic properties of hydrophilic and hydrophobic titanium surfaces evaluated with osteoblast-like cells (MG63) in coculture with human umbilical vein endothelial cells (HUVEC)
Objectives. Osteogenesis on titanium (Ti) surfaces is a complex process involving cell-substrate and cell-cell interaction of osteoblasts and endothelial cells. The aim of this study was to investigate the osteogenic properties of Ti surfaces on osteoblasts in the presence of endothelial cells (ECs).
Methods. Osteoblast-like cells (MG63 cells) and human umbilical vein endothelial cells (HUVECs) were grown in cocultures on four kinds of Ti surfaces: acid-etched (A), coarse-grit- blasted and acid-etched (SLA), hydrophilic A (modA) and hydrophilic SLA (modSLA) surfaces. MG63 cells in single cultures served as controls. Cell ratios and cell types in cocultures were determined and isolated using flow cytometry. Cell numbers were obtained by direct cell counting. In MG63 cells, alkaline phosphatase (ALP) activity was determined and protein levels of osteocalcin (OC) and osteoprotegerin (OPG) were detected with enzyme-linked immunosorbant assay (ELISA). The mRNA levels of ALP, OC and OPG of sorted MG63 cells were determined with real time polymerase chain reaction (PCR).
Results. MG63 cells proliferated in the presence of HUVECs, which showed higher cell numbers on Ti surfaces (A, SLA, modSLA) after 72 h, and lower cell numbers on Ti surfaces (modA, SLA, modSLA) after 120 h in comparison to single cultures. Protein and mRNA levels of ALP and OPG were higher in cocultures than in single cultures, while OC exhibited a lower expression. These three parameters were higher expressed on modA, SLA and modSLA surfaces compared to A surfaces.
Significance. Cocultures of osteoblasts and endothelial cells represent the most recently developed research model for investigating osteogenesis and angiogenesis which play both a major role in bone healing. This paper investigates for the first time the osteogenic properties of titanium surfaces used for dental implants with a coculture system with osteoblast-like cells and endothelial cells: (1) In cocultures with ECs (HUVECs) osteoblast-like cells (MG63 cells) show enhanced expression of early differentiation markers and osteogenic factors on Ti surfaces compared to single cultures of MG63 cells. (2) The differentiation and the expression of an osteogenic phenotype of osteoblast-like cells (MG63 cells) in coculture with ECs (HUVECs) is enhanced by both hydrophilicity and roughness of Ti surfaces. (c) 2010 Published by Elsevier Ltd on behalf of Academy of Dental Materials. All rights reserved