[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to demonstrate the ability of BMP-2-immobilized polycaprolactone (PCL) fibers modified using the γ-ray irradiation technique to induce the osteogenic differentiation of MG-63 cells. Poly acrylic acid (AAc) was grafted onto the PCL fibers by the γ-ray irradiation technique. BMP-2 was then subsequently immobilized onto the AAc-PCL fibers (BMP-2/AAc-PCL). PCL and surface-modified PCL fibers was characterized by evaluation with a scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and contact angle. The biological activity of the PCL and surface-modified PCL fibers were characterized by alkaline phosphatase (ALP) activity, calcium deposition, and the mRNA expression of osteocalcin and osteopontin in MG-63 cells. Successfully grafted AAc and PCL fibers with immobilized BMP-2 were confirmed by XPS results. The results of the contact angle showed that BMP-2/AAc-PCL fibers have more hydrophilic properties in comparison to PCL fibers. The ALP activity, calcium deposition, and gene expressions of MG-63 cells grown on BMP-2/AAc-PCL fibers showed greatly induced osteogenic differentiation in comparison to the PCL fibers. In conclusion, these results demonstrated that BMP-2/AAc-PCL fibers have the potential to effectively induce the osteogenic differentiation of MG-63 cells.
[Show abstract][Hide abstract] ABSTRACT: The osteogenic effect of culturing adipose-derived stem cells (ADSCs) on alendronate (Aln)-loaded polycarprolactone (PCL) nanofibrous scaffolds was evaluated by examining alkaline phosphatase (ALP) activity, calcium content, and expression of osteogenic differentiation genes in vitro. The 10% Aln/PCL nanofibrous scaffolds showed more ALP activity, mineralization, and osteocalcin and osteopontin mRNA than the 1% or 5% Aln/PCL nanofibrous scaffolds. The capacity of Aln/PCL nanofibrous scaffolds to regenerate new bone was studied in a rat calvarial defect model. New bone formation in vivo was evaluated by radiography, micro-computed tomography, and histological analysis. At 8 weeks after implantation, Aln/PCL scaffolds had a positive effect on bone regeneration and matrix formation. These results suggested that Aln/PCL nanofibrous scaffolds enhanced the osteogenic differentiation of ADSCs in vitro and bone formation in vivo.
Full-text · Article · Jun 2014 · Journal of Biomedical Nanotechnology
[Show abstract][Hide abstract] ABSTRACT: Curcumin has various pharmacological activities such as anti-inflammatory, antioxidant, antimicrobial and antitumor activity. However, its use has been limited due to its poor solubility in water and minimal systemic bioavailability. Thus, we developed curcumin-delivering heparin-based nanoparticles and evaluated the inhibition effects of osteoclastogenesis by curcumin-delivering heparin nanoparticles (Cur-HD NPs). Cur-HD NPs were dispersed well in aqueous solution by forming self-assembled nanoparticles and showed sustained release of curcumin. In vitro studies, HD NPs facilitated intracellular delivery of curcumin into macrophages and osteoclasts, and thus, Cur-HD NPs effectively inhibited osteoclastogenesis in a dose-dependent manner by suppressing tartrate-resistant acid phosphatase (TRAP) activity and TRAP-positive multinucleated cells as well as by reducing the expression of osteoclast marker genes (i.e., TRAP and nuclear factor of activated T cells cytoplasmic 1 (NFATc1)). Furthermore, Cur-HD NPs markedly stimulated apoptosis of osteoclasts. Therefore, we hope that Cur-HD NPs will be useful nanodrugs for the treatment of bone-related diseases.
Full-text · Article · Jun 2014 · Macromolecular Research
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to assess whether carboxymethyl cellulose- (CMC-) based hydrogel containing BioC (biphasic calcium phosphate (BCP); tricalcium phosphate (TCP) : hydroxyapatite (Hap) = 70 : 30) and bone morphogenic protein-2 (BMP-2) led to greater bone formation than CMC-based hydrogel containing BioC without BMP-2. In order to demonstrate bone formation at 4 and 8 weeks, plain radiographs, microcomputed tomography (micro-CT) evaluation, and histological studies were performed after implantation of all hybrid materials on an 8 mm defect of the right tibia in rats. The plain radiographs and micro-CT analyses revealed that CMC/BioC/BMP-2 (0.5 mg) led to much greater mineralization at 4 and 8 weeks than did CMC/BioC or CMC/Bio/BMP-2 (0.1 mg). Likewise, bone formation and bone remodeling studies revealed that CMC/BioC/BMP-2 (0.5 mg) led to a significantly greater amount of bone formation and bone remodeling at 4 and 8 weeks than did CMC/BioC or CMC/BioC/BMP-2 (0.1 mg). Histological studies revealed that mineralized bone tissue was present around the whole circumference of the defect site with CMC/BioC/BMP-2 (0.5 mg) but not with CMC/BioC or CMC/BioC/BMP-2 (0.1 mg) at 4 and 8 weeks. These results suggest that CMC/BioC/BMP-2 hybrid materials induced greater bone formation than CMC/BioC hybrid materials. Thus, CMC/BioC/BMP-2 hybrid materials may be used as an injectable substrate to regenerate bone defects.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to investigate the effect of functionalized titanium (Ti) with alendronate (Aln) and bone morphogenic protein-2 (BMP-2) for enhancement of osteoblast activity in vitro. Aln and/or BMP-2 were sequentially immobilized to the heparinized-Ti (Hep-Ti) surface. The compositions of pristine Ti and Hep-Ti with or without Aln and/or BMP-2 were characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). Aln and/or BMP-2 onto Hep-Ti surface were released in a sustained manner. Osteoblast activities on all Ti substrates were investigated by cell proliferation assays, alkaline phosphate (ALP) activity, calcium deposition, gene expressions of osteocalcin and osteopontin. Aln/BMP-2/Hep-Ti significantly enhanced ALP activity, calcium mineral deposition, and gene expressions of osteoblast cells when compared with pristine Ti, Aln/Hep-Ti, and BMP-2/Hep-Ti. From these results, functionalized Ti substrates with alendronate and BMP-2 such as Aln/BMP-2/Hep-Ti are a promising material for the enhanced osteoblast activities in orthopedic and dental fields.
Full-text · Article · Dec 2013 · Tissue Engineering and Regenerative Medicine
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to investigate the improvement in osteoblast functions by using bone morphogenetic protein-2 (BMP-2) immobilized heparin-coated chitosan scaffolds and comparing it with that using chitosan scaffold or BMP-2/chitosan scaffold in vitro. BMP-2 was released from the heparin-coated chitosan scaffold in a sustained manner compared to that released from the chitosan scaffold. The osteoblast functions of MG-63 cells grown on the chitosan scaffold, the BMP-2/chitosan scaffold, the BMP-2/Hep/chitosan scaffold were investigated by assessing cell proliferation, alkaline phosphatase (ALP) activity, calcium deposition, and gene expression. The results of the in vitro studies demonstrated that MG-63 cells grown on the BMP-2/Hep/chitosan scaffold showed a significant increment in ALP activity, and calcium deposition as compared to those grown on the chitosan scaffold by sustained release of BMP-2 due to the influence of heparin. Therefore, BMP-2 immobilized heparin-coated chitosan scaffolds are promising materials for improving osteoblast functions through sustained release of BMP-2.
No preview · Article · Aug 2013 · Tissue Engineering and Regenerative Medicine
[Show abstract][Hide abstract] ABSTRACT: The aim of orthopedic and dental tissue engineering is to generate synthetic bone-graft tissue substitutes. It is generally comprised through the combination of viable cells, a scaffolding material, and sometimes the inclusion of bone morphogenic proteins. The object of this study is to develop novel bone-grafting scaffolds that enhance osteoblast activity. We were fabricated the chitosan scaffolds with channel-shaped and spherically shaped pore morphologies. Also, Bone morphogenic protein-2 (BMP-2) was sequentially immobilized to the heparinized-chitosan (Hep-chitosan) scaffolds. Osteoblast activities of all chitosan scaffolds were investigated by a cell proliferation assay, alkaline phosphatase (ALP) activity, calcium deposition, and the expression of osteogenic markers. The results showed that BMP-2-immobilizing heparinized-chitosan (BMP-2/Hep-chitosan) scaffolds significantly enhanced ALP activity and calcium deposition of the osteoblast cells when compared with chitosan scaffolds only. Also, mRNA expressions of osteocalcin and osteopontin of osteoblast cells cultured on BMP-2 (100 ng)/Hep-chitosan scaffolds were increased versus chitosan scaffolds only. Taken together, BMP-2 (100 ng)/Hep-chitosan scaffolds could achieve the functions of excellent osteoblast promotion. Therefore, osteoinductive protein-functionalizing scaffold substrates such as BMP-2/Hepchitosan scaffolds are a promising material for the enhanced osteoblast activity in orthopedic and dental fields.
Full-text · Article · Jun 2013 · Tissue Engineering and Regenerative Medicine
[Show abstract][Hide abstract] ABSTRACT: Distraction osteogenesis (DO) is an increasingly popular technique used to stimulate new bone formation to treat orthopedic disorders resulting from bone defects and deficits. Because of various possible complications that can occur during the long consolidation period, the development of procedures to accelerate regenerated ossification is clearly desirable. The purpose of this study was to evaluate the effect of single insertions of bone morphogenic protein-2 (BMP-2), delivered by tri-calcium phosphate (TCP)/hydroxyapatite (HA), administered at osteotomy sites, on the rate of new bone formation during DO in a rat model.
Thirty-six male Sprague-Dawley rats, aged 12 weeks and weighing a mean (± standard deviation) of 401 ± 14 g, were used in this study. The animals were randomized into three groups of 12 rats each. Group I served as a control, group II was treated with only TCP/HA, and group III was treated with recombinant human (rh) BMP-2-coated TCP/HA. Materials were inserted into the medullary canal at the femoral osteotomy site at the end of the lengthening period. After a 7-day latent phase, distraction was commenced on day 0 at a rate of 0.50 mm every 6 h for 5 days (2 mm daily), resulting in a total of 10 mm of lengthening by day 5. At two different time-points [at 4 weeks (day 33) and 8 weeks (day 61) after cessation of distraction], the progress of bone formation was determined with microcomputed tomography (micro-CT), histology and real-time polymerase chain reaction (PCR). The mean and standard deviation of the values obtained from the experiment were computed and statistical analyses performed using anova. Statistical significance was established at P < 0.05. Results. Radiographically, all group III rat femurs exhibited bridging callus formation 8 weeks after cessation of distraction, whereas group II rat femurs demonstrated non-bridging callus formation. None of the group I rat femurs showed callus in the central zone of the distraction gap. For micro-CT, bone formation and remodeling of the distraction regeneration with beta-TCP/HA coated with rhBMP-2 had greater values than the control sides at all time-points. Two-dimensional quantitative analysis of the distraction regeneration showed that the bone volume of group III had higher values than groups I and II at 4 weeks (P < 0.05). This difference was also evident at 8 weeks. With hematoxylin and eosin (H&E) staining, the control group (group I) did not show any bone tissue at the distraction site. In group II at 4 weeks, abundant fibrous tissue surrounding the particles was visible with some areas of woven bone. At 8 weeks, the woven bone covered the particles but not the whole circumference. In group III at 4 weeks, much of the woven bone surrounded the particle with some fibrocartilagenous materials. At 8 weeks, woven bone covering the whole circumference of the particles was visible.
Application of rhBMP-2, at the end of the rather rapid distraction period, as a single bolus significantly increased the osteogenic process, while beta-TCP/HA behaved effectively as a sustained delivery system for this osteoinductive protein.
[Show abstract][Hide abstract] ABSTRACT: Stromal vascular fractions (SVF) from adipose tissue have heterogeneous cell populations, and include multipotent adipose-derived stem cells. The advantages of using of SVF include the avoidance of an additional culture period, a reduced risk of extensive cell contamination, and cost-effectiveness.
Unilateral 20-mm mid-diaphyseal segmental defects in rabbit ulna were treated with one of the following: polylactic glycolic acid (PLGA) scaffold alone (group 1, control), a PLGA scaffold with undifferentiated SVF cells (group 2), or a PLGA scaffold with osteogenically differentiated SVF cells (group 3). At 8 weeks after implantation, five rabbits in each treatment group were killed to assess bone defect healing by plain radiography, quantitative microcomputed tomography and histology.
The SVF cells were well grown on PLGA scaffolds and expressed type I collagen and alkaline phosphatase (ALP). The intensity of ALP and OPN gene expressions in osteogenic medium culture were increased from 14 days to 28 days. In vivo evaluations at 8 weeks showed that treatment of SVF cells with or without osteogenic differentiation resulted in more bone formation in the critically sized segmental defects than PLGA scaffold alone. Osteogenically differentiated SVF cells significantly enhanced bone healing compared with undifferentiated SVF cells.
Adipose-derived stromal SVF showed osteogenic potential in vitro. Accordingly, SVF could provide a cell source for bone tissue engineering. However, treatment with uncultured SVF cells on bone healing was not satisfactory in the in vivo animal model.
[Show abstract][Hide abstract] ABSTRACT: The choice of an appropriate carrier and its microarchitectural design is integral in directing bone ingrowth into the defect site and determining its subsequent rate of bone formation and remodeling. We have selected a three-dimensional polycaprolactone (PCL) scaffold with an interconnected honeycomb-like porous structure to provide a conduit for vasculature ingrowth as well as an osteoconductive pathway to guide recruited cells responding to a unique triphasic release of osteoinductive bone morphogenetic proteins (BMP) from these PCL scaffolds. We hypothesize that the use of recombinant human bone morphogenetic protein 2 (rhBMP2)-PCL constructs promotes rapid union and bone regeneration of a large defect. Results of our pilot study on a unilateral 15 mm mid-diaphyseal segmental rabbit ulna defect demonstrated enhanced bone healing with greater amount of bone formation and bridging under plain radiography and microcomputed tomography imaging when compared with an empty PCL and untreated group after 8 weeks postimplantation. Quantitative measurements showed significantly higher bone volume fraction and trabecular thickness, with lower trabecular separation in the rhBMP2-treated groups. Histology evaluation also revealed greater mature bone formation spanning across the entire scaffold region compared with other groups, which showed no bone regeneration within the central defect zone. We highlight that it is the uniqueness of the scaffold having a highly porous network of channels that promoted vascular integration and allowed for cellular infiltration, leading to a discontinuous triphasic BMP2 release profile that mimicked the release profile during natural repair mechanisms in vivo. This study serves as preclinical evidence demonstrating the potential of combining osteoinductive rhBMP2 with our PCL constructs for the repair of large defects in a large animal model.
No preview · Article · Jun 2011 · Tissue Engineering Part A
[Show abstract][Hide abstract] ABSTRACT: Microfracture of cartilage induces migration of bone-marrow-derived mesenchymal stem cells. However, this treatment often results in fibrocartilage regeneration. Growth factors such as bone morphogenetic protein (BMP)-2 induce the differentiation of bone-marrow-derived mesenchymal stem cells into chondrocytes, which can be used for hyaline cartilage regeneration. Here, we tested the hypothesis that long-term delivery of BMP-2 to cartilage defects subjected to microfracture results in regeneration of high-quality hyaline-like cartilage, as opposed to short-term delivery of BMP-2 or no BMP-2 delivery. Heparin-conjugated fibrin (HCF) and normal fibrin were used as carriers for the long- and short-term delivery of BMP-2, respectively. Rabbit articular cartilage defects were treated with microfracture combined with one of the following: no treatment, fibrin, short-term delivery of BMP-2, HCF, or long-term delivery of BMP-2. Eight weeks after treatment, histological analysis revealed that the long-term delivery of BMP-2 group (microfracture + HCF + BMP-2) showed the most staining with alcian blue. A biochemical assay, real-time polymerase chain reaction assay and Western blot analysis all revealed that the long-term delivery of BMP-2 group had the highest glucosaminoglycan content as well as the highest expression level of collagen type II. Taken together, the long-term delivery of BMP-2 to cartilage defects subjected to microfracture resulted in regeneration of hyaline-like cartilage, as opposed to short-term delivery or no BMP-2 delivery. Therefore, this method could be more convenient for hyaline cartilage regeneration than autologous chondrocyte implantation due to its less invasive nature and lack of cell implantation.
No preview · Article · Mar 2011 · Tissue Engineering Part A
[Show abstract][Hide abstract] ABSTRACT: Hueter-Volkmann's law regarding growth modulation suggests that increased pressure on the end plate of bone retards the growth (Hueter) and conversely, reduced pressure accelerates the growth (Volkmann). Literature described the same principle in Rat-tail model. Human spine and its deformity i.e. scoliosis has also same kind of pattern during the growth period which causes wedging in disc or vertebral body.
This cross sectional study in 150 patients of adolescent idiopathic scoliosis was done to evaluate vertebral body and disc wedging in scoliosis and to compare the extent of differential wedging of body and disc, in thoracic and lumbar area. We measured wedging of vertebral bodies and discs, along with two adjacent vertebrae and disc, above and below the apex and evaluated them according to severity of curve (curve < 30 degrees and curve > 30 degrees ) to find the relationship of vertebral body or disc wedging with scoliosis in thoracic and lumbar spine. We also compared the wedging and rotations of vertebrae.
In both thoracic and lumbar curves, we found that greater the degree of scoliosis, greater the wedging in both disc and body and the degree of wedging was more at apex supporting the theory of growth retardation in stress concentration area. However, the degree of wedging in vertebral body is more than the disc in thoracic spine while the wedging was more in disc than body in lumbar spine. On comparing the wedging with the rotation, we did not find any significant relationship suggesting that it has no relation with rotation.
From our study, we can conclude that wedging in disc and body are increasing with progression on scoliosis and maximum at apex; however there is differential wedging of body and disc, in thoracic and lumbar area, that is vertebral body wedging is more profound in thoracic area while disc wedging is more profound in lumbar area which possibly form 'vicious cycle' by asymmetric loading to spine for the progression of curve.
[Show abstract][Hide abstract] ABSTRACT: Bone-tendon junction injuries have poor healing potential. This study evaluated the role of TGF-beta and BMP-2 in a fibrin glue carrier in healing of injuries at bone-tendon junction. Seventy-two skeletally mature male rabbits were divided into 4 groups. The tendo-Achilles was surgically transected at its insertion and reattached with a pullout suture. Group 1 served as a control. In groups 2, 3, and 4, fibrin glue, a mixture of TGF-beta and fibrin glue, and a mixture of BMP-2 and fibrin glue were injected into the bone-tendon junction. The animals were sacrificed at 2, 4 and 8 weeks after surgical procedure. The addition of TGF-beta to fibrin glue did not significantly improve the biomechanical properties of repair tissue. BMP-2 in combination with fibrin glue accelerates healing in a bone-tendon injury and also improves the histological and biomechanical properties of the repair tissue so formed.
No preview · Article · Feb 2007 · Connective tissue research