Release of VEGF from dental implant improves osteogenetic process: Preliminary in vitro tests

INTRODUCTION: During osseointegration process, the presence of an inflammatory event could negatively influence the proper osteogenetic ability of the implant surface. In order to reduce this possibility, an implementation of angiogenetic event through the release of Vascular Endothelial Growth Factor (VEGF) can be a tool as co-factor for osteoblastic differentiation. In this paper, novel dental implant surfaces enriched with VEGF have been tested. MATERIAL AND METHODS: The ability of VEGF-enriched titanium implants to improve the osteogenetic properties of Mesenchymal stem cells (MSC), also in the presence of an inflammatory environment, have been in vitro tested. Molecular biology, morphological analyses, and biochemical tests have been performed in order to confirm biological properties of these surfaces. RESULTS: Our results confirm that the presence of VEGF onto the implant surface is able not only to protect the cells from in vitro aging and from Reactive Oxygen Species (ROS) damage, but it also improves their osteogenic and endothelial differentiation, even in the presence of inflammatory cytokines. CONCLUSION: This study establishes a biologically powerful novel tool that could enhance bone repair in dental implant integration

Porcine bone scaffolds adsorb growth factors secreted by MSCs and improve bone tissue repair

An ideal tissue-engineered bone graft should have both excellent pro-osteogenesis and pro-angiogenesis properties to rapidly realize the bone regeneration in vivo . To meet this goal, in this work a porcine bone scaffold was successfully used as a Trojan horse to store growth factors produced by mesenchymal stem cells (MSCs). This new scaffold showed a time-dependent release of bioactive growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), in vitro . The biological effect of the growth factors-adsorbed scaffold on the in vitro commitment of MSCs into osteogenic and endothelial cell phenotypes has been evaluated. In addition, we have investigated the activity of growth factor-impregnated granules in the repair of critical-size defects in rat calvaria by means of histological, immunohistochemical, and molecular biology analyses. Based on the results of our work bone tissue formation and markers for bone and vascularization were significantly increased by the growth factor-enriched bone granules after implantation. This suggests that the controlled release of active growth factors from porcine bone granules can enhance and promote bone regeneratio

Nanotechnology-based therapies for skin wound regeneration

The cutting-edge combination of nanotechnology with medicine offers the unprecedented opportunity to create materials and devices at a nanoscale level, holding the potential to revolutionize currently available macroscale therapeutics. Nanotechnology already provides a plethora of advantages to medical care, and the success of nanoparticulate systems suggests that a progressive increase in the exploration of their potential will take place in the near future. An overview on the current applications of nanotechnology to wound healing and wound care is presented

Biocompatibility and antibacterial properties of zirconium nitride coating on titanium abutments: An in vitro study

Improving soft tissue attachment and reducing bacterial colonization on titanium abutments are key factors for the long-term maintenance of healthy soft and hard peri-implant tissues. This in vitro study was conducted to compare the biocompatibility and antibacterial activity of four different surfaces: uncoated Ti6Al4V, anodized, and coated with titanium nitride or zirconium nitride. Surface topography was investigated with a high-resolution system for measuring surface finishes. Human gingival fibroblast (HGF) adhesion and proliferation were examined using MTT assay, Scanning Electron Microscopy (SEM) imaging, immunofluorescence analysis and real-time PCR for selected target genes. The hemolysis and AMES tests were performed to assess the chemical compounds' blood compatibility and mutagenic potential, respectively. Antibacterial activity was tested against five bacterial strains isolated from the oral cavity (Streptococcus salivarius, S. sanguinis, S. mutans, S. sobrinus, S. oralis), and the percentage of dead bacteria was calculated. Roughness measurements confirmed a substantial similarity between the surfaces and their compatibility with clinical applications. MTT assay, SEM analysis and immunofluorescence staining showed adhesion and proliferation of HGFs cultured on all the examined surfaces. PCR confirmed that HGFs produced extracellular matrix components efficiently on all the surfaces. No hemolytic activity was detected, and the AMES test confirmed the surfaces' clinical safety. For all tested bacterial strains, biofilms grown on the zirconium nitride surface showed a higher percentage of dead bacteria than on the other disks. The titanium nitride surface inactivated bacterial biofilms, too, but to a lesser extent

Bioactive glass-ceramic scaffolds from novel 'inorganic gel casting' and sinter-crystallization

Highly porous wollastonite-diopside glass-ceramics have been successfully obtained by a new gel-casting technique. The gelation of an aqueous slurry of glass powders was not achieved according to the polymerization of an organic monomer, but as the result of alkali activation. The alkali activation of a Ca-Mg silicate glass (with a composition close to 50 mol % wollastonite50 mol % diopside, with minor amounts of Na2O and P2O5) allowed for the obtainment of well-dispersed concentrated suspensions, undergoing progressive hardening by curing at low temperature (40 degrees C), owing to the formation of a C-S-H (calcium silicate hydrate) gel. An extensive direct foaming was achieved by vigorous mechanical stirring of partially gelified suspensions, comprising also a surfactant. The open-celled structure resulting from mechanical foaming could be frozen' by the subsequent sintering treatment, at 900-1000 degrees C, causing substantial crystallization. A total porosity exceeding 80%, comprising both well-interconnected macro-pores and micro-pores on cell walls, was accompanied by an excellent compressive strength, even above 5 MPa

The biological properties of OGI surfaces positively act on osteogenic and angiogenic commitment of mesenchymal stem cells

Osteogenesis process displays a fundamental role during dental implant osteointegration. In the present work, we studied the influence of Osteon Growth Induction (OGI) surface properties on the angiogenic and osteogenic behaviors of Mesenchymal Stem cells (MSC). MSC derived from dental pulp and HUVEC (Human Umbilical Vein Endothelial Cells) were grown in on OGI titanium surfaces, and cell proliferation and DNA synthesis were evaluated by MTT [3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide] test and DNA quantification. Gene expression has been performed in order to evaluate the presence of mRNA related to endothelial and osteogenesis markers. Moreover, morphological and biochemical analyses of osteogenesis commitments has been performed. On OGI surfaces, MSC and HUVEC are able to proliferate. Gene expression profiler confirms that MSC on OGI surfaces are able to express endothelial and osteogenic markers, and that these expression are higher compared the expression on control surfaces. In conclusion On OGI surfaces proliferation, expression and morphological analyses of angiogenesis-associated markers in MSC are promoted. This process induces an increasing on their osteogenesis commitmen

Bioactive sphene-based ceramic coatings on cpTi substrates for dental implants: An in vitro study

Titanium implant surface modifications have been widely investigated to favor the process of osseointegration. The present work aimed to evaluate the effect of sphene (CaTiSiO5) biocoating, on titanium substrates, on the in vitro osteogenic differentiation of Human Adipose-Derived Stem Cells (hADSCs). Sphene bioceramic coatings were prepared using preceramic polymers and nano-sized active fillers and deposited by spray coating. Scanning Electron Microscopy (SEM) analysis, surface roughness measurements and X-ray diffraction analysis were performed. The chemical stability of the coatings in Tris-HCl solution was investigated. In vitro studies were performed by means of proliferation test of hADSCs seeded on coated and uncoated samples after 21 days. Methyl Thiazolyl-Tetrazolium (MTT) test and immunofluorescent staining with phalloidin confirmed the in vitro biocompatibility of both substrates. In vitro osteogenic differentiation of the cells was evaluated using Alizarin Red S staining and quantification assay and real-time PCR (Polymerase Chain Reaction). When hADSCs were cultured in the presence of Osteogenic Differentiation Medium, a significantly higher accumulation of calcium deposits onto the sphene-coated surfaces than on uncoated controls was detected. Osteogenic differentiation on both samples was confirmed by PCR. The proposed coating seems to be promising for dental and orthopedic implants, in terms of composition and deposition technology

Skin Substitutes

On tissue engineering field the research about skin substitutes represents historically the most promising approach to heal acute and chronic skin wounds, reducing requirements for donor skin autografts. Aim of this chapter is to made the state of art of the most important skin substitutes and to resume the principal tissue engineering techniques for its in vitro reconstruction. In the first part we will pay the attention to the description of the evolutive course of skin substitutes, stressing the main steps happened thanks to the important inputs coming from biotechnologies progresses and clinical practice. Since then the research in bioengineering skin, moved by clinical pressing of reconstructive and burn surgery, made progresses trying to develop cutaneous substitutes very similar to native skin by a morpho-functional point of view. So it has been possible, starting from a 2X2 cm skin human biopsy, to realize completely autologous cutaneous substitutes not only composed of two many structures of skin, dermis and epidermis, but containing also other important components: microvascular network, micro nervous network, skin immonocompetent system and melanocyte system. The final goal is to develop effective and easy handling skin substitutes that could be reproduce human skin anatomy and physiology, introducing new advantages linked to successful grafting and then to satisfactory clinical results by functional and aesthetic point of view

Immunomodulatory role of adipose-derived stem cells on equine endometriosis

Endometriosis is a degenerative process due to a chronic inflammatory damage leading to extracellular matrix components deposition and glandular fibrosis. It is known that mesenchymal stem cells secrete a wide range of bioactive molecules, some of them modulating the immune inflammatory response, and others providing regeneration and remodeling of injured tissue. We have performed in vitro experiments in order to analyze the capability of allogenic equine adipose-derived stem cells (ADSCs) to infiltrate mares' endometrial tissues and to stimulate the expression of cytokines and metallopeptidases. Differences in the biologic response to the exposure to ADSCs between pathological and healthy endometrial tissue have been identified. These results could challenge researchers to progress forward with future studies for the development of a biological therapy with a possible application in translational medicine