The effect of five proteins on stem cells used for osteoblast differentiation and proliferation: a current review of the literature.

Bone-tissue engineering is a therapeutic target in the field of dental implant and orthopedic surgery. It is therefore essential to find a microenvironment that enhances the growth and differentiation of osteoblasts both from mesenchymal stem cells (MSCs) and those derived from dental pulp. The aim of this review is to determine the relationship among the proteins fibronectin (FN), osteopontin (OPN), tenascin (TN), bone sialoprotein (BSP), and bone morphogenetic protein (BMP2) and their ability to coat different types of biomaterials and surfaces to enhance osteoblast differentiation. Pre-treatment of biomaterials with FN during the initial phase of osteogenic differentiation on all types of surfaces, including slotted titanium and polymers, provides an ideal microenvironment that enhances adhesion, morphology, and proliferation of pluripotent and multipotent cells. Likewise, in the second stage of differentiation, surface coating with BMP2 decreases the diameter and the pore size of the scaffold, causing better adhesion and reduced proliferation of BMP-MSCs. Coating oligomerization surfaces with OPN and BSP promotes cell adhesion, but it is clear that the polymeric coating material BSP alone is insufficient to induce priming of MSCs and functional osteoblastic differentiation in vivo. Finally, TN is involved in mineralization and can accelerate new bone formation in a multicellular environment but has no effect on the initial stage of osteogenesis.

The enhancement of osteogenesis through the use of dental pulp pluripotent stem cells in 3D.

The potential for osteogenic differentiation of dental pulp mesenchymal stem cells (DPMSCs) in vitro and in vivo has been well documented in a variety of studies. Previously, we obtained a population of cells from human dental pulp called dental pulp pluripotent stem cells (DPPSCs) that could differentiate into mesodermal, ectodermal and endodermal progenies. We compared the osteogenic capacity of DPPSCs and DPMSCs that had been isolated from the same donors (N=5) and cultivated in the same osteogenic medium in 3D (three dimensions) Cell Carrier glass scaffolds. We also compared the architecture of bone-like tissue obtained from DPPSCs and human maxillary bone tissue. Differentiation was evaluated by scanning electron microscopy, whereas the expression of bone markers such as ALP, Osteocalcin, COLL1 and Osteonectin was investigated by quantitative real time polymerase chain reaction (qRT-PCR). We also used calcium quantification, Alizarin red staining and alkaline phosphatase (ALP) activity to compare the two cell types. New bone tissue formed by DPPSCs was in perfect continuity with the trabecular host bone structure, and the restored bone network demonstrated high interconnectivity. Significant differences between DPPSCs and DPMSCs were observed for the expression of bone markers, calcium deposition and ALP activity during osteogenic differentiation; these criteria were higher for DPPSCs than DPMSCs. Both DPPSCs and differentiated tissue showed normal chromosomal dosage after being cultured in vitro and analysed using short-chromosome genomic hybridisation (short-CGH). This study demonstrates the stability and potential for the use of DPPSCs in bone tissue engineering applications.

Viability of maxillary bone harvesting by using different osteotomy techniques. A pilot study.

The use of autogenous grafts is still considered in bone regeneration surgeries. However, the bone cell viability of such grafts after being harvested from donor sites remains a matter of debate. The aim of the present study is to evaluate particulated and block bone cell viability, in terms of presence or absence of apoptosis and necrosis, obtained from different maxillary intra-oral harvesting methods: bone scraper, rotary carbide burs and piezoelectric device. Five healthy patients were enrolled in the study. The patients required sinus augmentation by lateral window approach. The bone was harvested by the bone scraper, piezoelectric device and rotary surgical instrument. The samples were processed with the Annexin V/FITC (fluorescein isothiocyanate stain) kit and were analyzed by means of Fluoresence-Activated Cell Sorted (FACS) technique. Within the limitations of this pilot study, the results indicated that autogenous bone chips collected from the three harvesting methods presented a large percentage of apoptotic cells, although large scale production of necrotic cells was not detected. In summary, although rotary surgical instrument and piezoelectric devices are frequently used instruments for oral osteotomy, fresh autogenous bone chips collected from them did not present a viable bone cell source.