In vitro calcified matrix deposition by human osteoblasts onto a zinc-containing bioactive glass

Bioactive glasses synthesized by the sol-gel technique possess many of the qualities associated with an ideal scaffold material for a bone graft substitute. In view of the potential clinical applications, we performed a detailed in vitro study of the biological reactivity of synthesized 58S bioactive glass containing-zinc, in terms of osteoblast morphology, proliferation, and deposition of a mineralized extracellular matrix (ECM). Human Sarcoma Osteoblast (SAOS-2) cells were used to i) assess cytotoxicity by lactate dehydrogenase (LDH) release and ii) evaluate the deposition of a calcified extracellular matrix by ELISA assay and quantitative RT-PCR (qRT-PCR). In comparison with pure silica and 58S, the 58S-Zn0.4 bioglass showed a significant increase in cellular proliferation and deposition of ECM components such as decorin, fibronectin, osteocalcin, osteonectin, osteopontin, type-I and -III collagens. Calcium deposition was significantly higher than on pure silica and 58S samples. Also Alkaline phosphatase (ALP) activity and its protein content was higher with respect to pure silica and 58S. qRT-PCR analysis revealed the up-regulation of type-I collagen, bone sialoprotein and osteopontin genes. All together these results demonstrate the cytocompatibility of 58S-Zn0.4 bioglass and its capability to promote osteoblast differentiation

Strategies combining cells and scaffolds for bone tissue engineering

Engineering bone typically uses highly porous scaffolds, osteoblasts or cells that can become osteoblasts, and regulating factors that promote cell attachment, differentiation, and mineralized bone formation. In this study we investigated the effects of the electromagnetic stimulation on SAOS-2 cells, from a human osteosarcoma cell line using a sintered 3D titanium scaffold. In comparison with control conditions (standard cell culture incubator, where no electromagnetic stimulus was detectable), the electromagnetic stimulus (magnetic field, 2 mT; frequency, 75 Hz) increased the cell proliferation and the surface coating with decorin, osteocalcin, osteopontin, and type-I collagen. The electromagnetic stimulus aimed at obtaining an improved cell proliferation and production of bone proteins, with a consequent surface coating of the scaffold. The protein -coated 3D titanium scaffold could be used, in clinical applications, as an implant for bone repair

HUMAN CORD STROMA CELLS AFTER CO-CULTURE WITH HUMAN DENTAL PULP CELLS UNDERGO TO OSTEOGENIC DIFFERENTIATION THROUGH A BMP 2-MEDIATED PATHWAY

In the human embryonic development, the umbilical cord comes from trofoblast, the embryo part that will not originate differentiated tissues but is committed to organize the trophic system for the developing embryo. The easy collecting procedure of the cord stroma and the plasticity of the cells isolated make it a suitable source for the collection of human mesenchymal cells. At the present moment, the bone needing for clinical therapies is increasing and identification of an alternative human cellular resource, easy to collect and able to produce a well-differentiated extracellular bone matrix, acts in this way. In this paper we demonstrate that the cord stroma mesenchymal progenitors are easy to commit into osteogenic lineages after exposition to conditionated medium of Runx2+/OC+positive cells, obtained from differentiation of human dental pulp stem cell, cells that are bone committed cells and can be used to studythe bone regeneration mechanisms. The chance to obtain the osteogenic differentiation and the production of a well-differentiated bone matrix just culturing the cells with the conditionated medium of Runx2+/OC+ cells is very important in the perspective of clinical application of these MS