Papers by Keyword: Osteogenesis

Abstract: Dogs underwent high-frequency automated tibia lengthening with the Ilizarov apparatus over a 1.8-mm hydroxyapatite-coated intramedullary titanium wire. Daily distraction was 3.0 mm with a fraction of 0.125 mm/h and continued ten days. The regenerate was well vascularized, had zonal structure and was of normal or hyperplastic type to the end of distraction. Osteogenesis was fast and complete. The wire served for both mechanical and biological reinforcement of the bone callus and provided reduction of external fixation time. Mean consolidation time with the apparatus on the limb was 13.83±4.02 days. Overall, external fixation index was 10.5 days/cm and 4.8 days/cm in the consolidation phase.

Abstract: Some biomaterials can be used to promote tissue repair process. The biological substitutes (biomaterials such as hydroxyapatite beads) can be used with some advantages and purpose of mimicking responses to on-site repair of the injured bone. The objective of this study was to evaluate the osteogenic potential of the biomaterial composed of hydroxyapatite and alginate in place of the critical defect. bioceramic samples stoichiometric hydroxyapatite was produced by the precipitation method, wet method with ion molar ratio of Ca 10 (PO 4) 6 (OH) 2, in which the Ca / P ratio was equal to 1.67. The reaction conditions were favorable to the composition of a biomaterial with crystalline phase. The synthesis of the biomaterial composed of hydroxyapatite and alginate microspheres (HAAlg5%; 200 ø 425mm) was obtained from two primary solutions with the aim of, in optimal reactive conditions, to form the precipitate. After synthesis the microspheres were implanted into the defect site. The potential effects of using HAAlg5% and the application of vibratory waves in the critical defect repair were unknown and the results described in this study are promising, considering the systemic therapy and at the site of injury. The biomaterial used promoted repair the injured tissue.

Abstract: Vascularization is a crucial process during bone development and regeneration. A number of studies have shown that the interaction between osteoblasts and endothelial cells plays a key role in osteogenesis by using co-culture system. However, vascularization strategies in cell-based bone tissue engineering depend on optimal culture conditions. In this study, we determined the optimal co-culture conditions in view of osteogenic parameters and examined the effects of angiogenic properties on osteogenesis. As for cell proliferation, the proportion of osteoblasts increased and that of endothelial cells decreased as culture period passed. Assessment of osteogenic differentiation shows that co-culture of osteoblasts and endothelial cells significantly increased alkaline phosphatase activity and expression of bone-related genes. Furthermore, abundant microcapillary-like structures were observed which endothelial cells self-assembled into branches and net-like structures. The use of endothelial cells would be a promising strategy to promote vascularization to support the bone regeneration. Combination of these cell-based approaches and tissue engineering like three-dimensional scaffolds could provide a novel treatment therapy for bone defects and bone diseases.

Abstract: Sinus floor augmentation (SFA) has become a well-established pre-implantology procedure for alveolar ridge augmentation of the posterior maxilla. Using bioceramic bone substitutes avoids second-site surgery for autograft harvesting. Compared to the bone substitutes which are currently clinically available, there is a significant need for bone substitutes which degrade more rapidly, but still stimulate osteogenesis at the same time. This has led to the development of bioactive, rapidly resorbable calcium alkali orthophosphate (CAOP) materials, which have a greater solubility than tricalcium phosphate. In this study the biodegradability and effect of a silica containing CAOP (Si-CAOP) on osteogenesis was evaluated in human biopsies sampled 6 months after SFA and compared to that of TCP utilizing hard tissue histology, histomorphometry and immunohistochemical analysis of osteogenic marker expression. Both materials facilitated bone formation and matrix mineralization, which were still actively progressing from the sinus floor in an apical direction 6 months after SFA. With the Si-CAOP grafting material however, bone formation, the bone-biomaterial-contact, i.e. bone-bonding, and particle degradation were significantly greater compared to TCP in the apical region of the biopsies, i.e. at the largest distance from the native bone of the sinus floor. This was accompanied by greater expression of Col I, BSP and OC in the newly formed bone tissue in the Si-CAP samples compared to TCP. Six months after implantation Si-CAOP facilitated greater bone formation and biodegradability than the TCP graft material, whose excellent osteoconductive properties have been widely documented. Consequently, Si-CAOP can be regarded as excellent grafting material for SFA in a clinical setting.

Abstract: Osteogenesis and degradability of bioresorbable biphasic gypsum-carbonated apatite granules (BPG) were investigated. Three different sizes of gypsum, 300-600 μm (small), 600-1000 μm (medium) and 1000-2000 μm (large), denoted as S, M and L respectively, were developed through the crushing and sieving method. Exposure of gypsum granules in carbonate and phosphate sources formed BPG through dissolution and precipitation mechanism. BPG was firstly examined by X-ray Diffractometer (XRD) and Fourier Transform Infrared Spectrometer (FTIR) to confirm its phase and chemical composition respectively. In-vitro cell proliferation, alkaline phosphatase (ALP) activity and adhesion of human osteoblast (hFOB) were investigated for osteogenesis evaluation. Degradability in phosphate buffer saline (PBS) was characterized by weight loss whereas apatite mineralization on the BPG surface was examined using Scanning Electron Microscope (SEM). BPG with 300-600 μm and 600-1000 μm enhanced osteogenic differentiation of hFOB and accelerated differentiation process better than 1000-2000 μm as indicated by cell proliferation and ALP activity. Good hFOB adhesion was observed on all BPG surfaces. The weight loss of L and M was 68% and 59%, respectively, which are higher than S at only 32%, indicating faster degradation of large BPG compared to smaller granules upon immersion for 35 days. This in turn, suggested the ionic dissolution of BPG which has contributed to the apatite formation on its surface. The results suggest, the BPG mimicked the bone matrix, exhibited good osteogenesis and degradability, which might be used as a potential candidate for bone tissue engineering.

Abstract: The microenvironment has been shown to regulate cellular functions including cell growth, differentiation, proliferation, migration, cancer development and metastasis. However, the underlying mechanism remains largely unclear. It has been reported that tension force is a key issue for osteogenesis of human mesenchymal stem cells (MSCs) and osteoblasts. In the present study, fibronectin film covered on glass substrate was made into square-shaped micro patterns. Osteoblasts cultured on this geometric substrate first located at the edge of the square. Next day the cells extended to the whole square. The results showed that geometric cues can control the growth of osteoblasts. Possible explanation is that the edge of the square provides higher tension force to the cell. These findings demonstrate that tension force from geometric shape is a positive signal for osteogenesis of osteoblasts and bone remodeling.

Abstract: This study evaluates the effect of two novel particulate silicon-doped calcium phosphate graft materials as compared to the currently clinically used material β-TCP on osteogenesis and bone formation after implantation in critical-size defects the sheep scapula. These materials were developed in order to create biodegradable bone substitute materials that degrade rapidly, but still stimulate osteogenesis at the same time, thereby resulting in bone repair and regeneration with fully functional bone tissue. All bone substitute materials studied facilitated excellent bony regeneration of critical-size defects in the sheep scapula. Of the three grafting materials studied, the calcium alkali orthophosphate material with the crystalline phase Ca₂KNa (PO₄)₂, with a small amorphous portion containing magnesium potassium phosphate and a small addition of sodium magnesium silicate had the greatest stimulatory effect on bone formation and expression of osteogenic markers, while exhibiting the highest biodegradability.

Abstract: Bone tissue in ideal conditions morphofunctional remodeling properly. The bone can be affected by fractures, tumors, hormonal dysfunction, senescence, genetic modifications, among others. In such circumstances, the proper diet, drug use, exercise and other factors are important to the prevention of bone mineral loss. The effect of kinesiotherapy obtained through the application of vibratory waves administered through the vibrating platform, Juvent1000 ® already been established in the prevention of bone mineral density, muscular trophism, among other systems in humans. The response by analyzing bone tissue of bone repair in critical defect is not known in experimental animals and in human clinical. This research evaluated the osteogenic potential critical defect in the calvaria of rats subjected to the application of vibratory waves obtained by vibrating platform and implant in the critical defect of rat calvaria. The bone tissue response was evaluated showed satisfactory results obtained in biological points 15, 45 and 120 days.

Abstract: Mesoporous bioactive glass (MBG) has superior bioactivity and degradation than non-mesoporous bioactive glass (BG) in vitro. But the biological effect of MBG in vivo is still unknown. In this study, MBG powders with 20μm were implanted into the femoral condyles in SD rats. BG powders with 20μm were used as a control. The local degradation and osteogenesis were observed at 1 week and 4 weeks after implantation, and the systemic toxicity of the degradation products were also evaluated simultaneously. The results revealed MBG powders had the faster rate of degradation and better osteogenesis effect than BG powders at 4 weeks, although the most of material still remained in situ. Histopathological analyses indicated the degradation products did not have any damage to major organs such as liver and kidney. In conclusion, this preliminary study demonstrated that MBG powders have more excellent biological effect at 4 weeks than that of BG in vivo. However the long-term effect needs to be confirmed.

Abstract: The aim of the present study is to evaluate the in vivo biological behaviour of porous β-CS/PDLGA scaffolds. The scaffolds were implanted in critical-sized femur defects ( 6 ×10 mm) for 4, 12 and 20 weeks with β-TCP scaffolds as the control. The in vivo bone regeneration of the scaffolds were investigated using sequential histological evaluations and Micro-CT technology. Results showed that the β-CS/PDLGA scaffolds could stimulate bone regeneration and degrade progressively at a rate proportionate with the regeneration of new bone as compared with β-TCP scaffolds. The present study suggested the potential application of β-CS/PDLGA scaffolds in hard tissue regeneration.