In this work, we combined tissue engineering and gene therapy technologies to develop a therapeutic platform for bone regeneration. We have developed photothermal fibrin-based hydrogels that incorporate degradable CuS nanoparticles (CuSNP) which transduce incident near-infrared (NIR) light into heat. A heat-activated and rapamycin-dependent transgene expression system was incorporated into mesenchymal stem cells to conditionally control the production of
Background.
There is a growing interest in the development of tissue engineering (TE) therapies to repair damaged bone. Among the scaffolds for TE applications, injectable hydrogels have demonstrated great potential as three-dimensional cell cultures in bone TE, owing to their high water content, porous structure that allows cell transplantation and proliferation, similarity to the natural extracellular matrix and ability to match irregular defects. We investigated whether fibrin-based hydrogels capable of transducing near infrared (NIR) energy into heat can be employed to lead bone repair. Hollow gold nanoparticles with a plasmon surface band absorption at ∼750 nm, a NIR wavelength within the so called “tissue optical window”, were used as fillers in injectable fibrin-based hydrogels. These composites were loaded with genetically-modified cells harbouring a heat-activated and rapamycin-dependent gene circuit to regulate transgenic expression of the reporter gene firefly luciferase (fLuc). NIR-responsive cell constructs were injected to fill a 4 mm diameter critical-sized defect (CSD) in the parietal bone of mouse calvaria. NIR-irradiation in the presence of rapamycin triggered a pattern of fLuc activity that faithfully matched the illuminated area of the implanted hydrogel. Having shown that this platform can control the expression of a transgene product, we tested its effectiveness on regulating the secretion of transgenic
Objectives. Fracture non-union poses a significant challenge to treating orthopaedic surgeons. These patients often require multiple surgical procedures. The incidence of complications after Autologous Bone Graft (ABG) harvesting has been reported up to 44%. These complications include persistent severe donor site pain, infection, heterotopic ossification and antalgic gait. We retrospectively compared the use of BMP-7 alone in long bone fracture Non-union, with patients in whom BMP-7 was used in combination with the Autologous Bone Graft (ABG). Material and Methods. The databases of our dedicated Limb Reconstruction Unit were searched for patient with three common long bone fractures Non-unions (Tibia, Femur and Humerus). The patients who had intra-operative use of
The feasibility of bone transport with bone substitute and the factors which are essential for a successful bone transport are unknown. We studied six groups of 12 Japanese white rabbits. Groups A to D received cylindrical autologous bone segments and groups E and F hydroxyapatite prostheses. The periosteum was preserved in group A so that its segments had a blood supply, cells, proteins and scaffold. Group B had no blood supply. Group C had proteins and scaffold and group D had only scaffold. Group E received hydroxyapatite loaded with recombinant human bone morphogenetic protein-2 and group F had hydroxyapatite alone. Distraction osteogenesis occurred in groups A to C and E which had osteo-conductive transport segments loaded with osteo-inductive proteins. We conclude that scaffold and proteins are essential for successful bone transport, and that bone substitute can be used to regenerate bone.
There is increasing application of bone morphogenetic proteins
(BMPs) owing to their role in promoting fracture healing and bone
fusion. However, an optimal delivery system has yet to be identified.
The aims of this study were to synthesise bioactive BMP-2, combine
it with a novel α-tricalcium phosphate/poly(D,L-lactide-co-glycolide)
(α-TCP/PLGA) nanocomposite and study its release from the composite. BMP-2 was synthesised using an Objectives
Methods
We performed a prospective, randomised double-blind study in 24 patients undergoing high tibial osteotomy to evaluate the effectiveness of human recombinant osteogenic protein (OP-1) on a collagen type-I carrier in a critically-sized fibular defect. The study had two phases, each evaluated by clinical, radiological and DEXA methods during the first postoperative year. The first concerned the validation of the model of the fibular defect, using positive (demineralised bone) and negative (untreated) controls. The second phase concerned the osteogenic potential of OP-1 on collagen type-I ν collagen type-I alone. The results of the first phase established the critically-sized nature of the defect. In the untreated group no bony changes were observed while, in the demineralised bone group, formation of new bone was visible from six weeks onwards. The results of the second phase showed no significant formation of new bone in the presence of collagen alone, while in the OP-1 group, all patients except one showed formation of new bone from six weeks onwards. This proved the osteogenic activity of OP-1 in a validated critically-sized human defect.
Growth factors produced by inflammatory cells and mesenchymal progenitors are required for proper bone regeneration. Signaling pathways activated downstream of these proteins work in concert and synergistically to drive osteoblast and/or chondrocyte differentiation. While dysregulation can result in abnormal healing, activating these pathways in the correct spatiotemporal context can enhance healing.
Osteoporosis is a systemic skeletal disorder characterized by reduced bone mass and deterioration of bone microarchitecture, which results in increased bone fragility and fracture risk. Casein kinase 2-interacting protein-1 (CKIP-1) is a protein that plays an important role in regulation of bone formation. The effect of CKIP-1 on bone formation is mainly mediated through negative regulation of the
Periosteal mesenchymal stem cells (PMSC) are an emerging niche of stem cells to enhance bone healing by tissue engineering process. They have to be differentiated into osteoprogenitors in order to synthesize new bone matrix. In vitro differentiation with specific differentiation medium (DM) is not exactly representative of what occurs in vivo. The interaction between PMSC and growth factors (GF) present in biological matrix is somewhat less understood. The goal of this study is to explore the possibility of spontaneous PMSC differentiation in contact with different biological matrices without DM. 500.000 porcine PMSC were seeded on 6-well plates and cultured with proliferation medium (PM). When reaching 80% confluence, biological samples (n=3) of demineralized bone matrix (DBM), decellularized porcine bone allograft (AOp), human bone allograft (AOh), human periosteum (HP) and human fascia lata (HFL) were added. Negative and positive control wells included cells with only PM or DM, respectively. The differentiation progress was assessed by Alizarin Red staining at days 7, 14 and 21.
Extensive bone defects, caused by severe trauma or resection of large bone tumors, are difficult to treat. Regenerative medicine, including stem cell transplantation, may provide a novel solution for these intractable problems and improve the quality of life in affected patients. Adipose-derived stromal/stem cells (ASCs) have been extensively studied as cell sources for regenerative medicine due to their excellent proliferative capacity and the ability to obtain a large number of cells with minimal donor morbidity. However, the osteogenic potential of ASCs is lower than that of bone marrow-derived stromal/stem cells. To address this disadvantage, our group has employed various methods to enhance osteogenic differentiation of ASCs, including factors such as
Although
We have developed plasmonic fibrin-based hydrogels that incorporate gold nanoparticles which transduce incident near-infrared (NIR) light into heat. Human adenovirus serotype type-5 vectors encoding a firefly luciferase (fLuc) coding sequence driven by a heat-inducible promoter were incorporated into the hydrogels. Transmission electronic microscopic analysis revealed that the adenoviral vectors were associated to the fibrin fibers. In vitro experiments in which human cells were cultured with plasmonic hydrogels showed that the adenoviral vectors can diffuse from the hydrogels, transduce the cells, and stimulate heat-induced transgene expression upon NIR irradiation. The hydrogels were implanted in 4.2 mm drill hole defects generated in the humerus of male rabbits. Three days after implantation, the defects were NIR-irradiated. Six h later, the animals were euthanized and samples from the bone defect zone were processed for immunohistochemical analyses using a specific fLuc antibody. The results showed strong expression of fLuc in tissues surrounding the implants of NIR-irradiated rabbits, while non- irradiated animals exhibited negligible expression. We next aimed to use the temperature increase to induce the production of transgenic
Objectives. Osteophytes are products of active endochondral and intramembranous ossification, and therefore could theoretically provide significant efficacy as bone grafts. In this study, we compared the bone mineralisation effectiveness of osteophytes and cancellous bone, including their effects on secretion of growth factors and anabolic effects on osteoblasts. Methods. Osteophytes and cancellous bone obtained from human patients were transplanted onto the calvaria of severe combined immunodeficient mice, with Calcein administered intra-peritoneally for fluorescent labelling of bone mineralisation. Conditioned media were prepared using osteophytes and cancellous bone, and growth factor concentration and effects of each graft on proliferation, differentiation and migration of osteoblastic cells were assessed using enzyme-linked immunosorbent assays, MTS ((3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)) assays, quantitative real-time polymerase chain reaction, and migration assays. Results. After six weeks, the area of mineralisation was significantly higher for the transplanted osteophytes than for the cancellous bone (43803 μm. 2. , . sd. 14660 versus 9421 μm. 2. , . sd. 5032, p = 0.0184, one-way analysis of variance). Compared with cancellous bone, the conditioned medium prepared using osteophytes contained a significantly higher amounts of transforming growth factor (TGF)-β1 (471 pg/ml versus 333 pg/ml, p = 0.0001, Wilcoxon rank sum test),
Osteoarthritis is a slowly progressive disease which includes the intervention of several cytokines and macrophage metalleinoproteinases reaction, leading to the degradation of the local cartilage but also having an impact on the serum acute phase proteins (APPs). Subsequently, biomarkers seem to be essential to estimate its progression and the need for any surgical intervention such as total arthroplasty, but also can be used as therapeutic agents. Recently, among APPs, fetuin-A drew attention regarding its possible anti-inflammatory role in animal models but also as a therapeutic agent in the inflammatory joint disease in clinical trials. The purpose of this study is to investigate the possible attenuating role of the intra-articular administration of Fetuin-A in post-traumatic induced secondary osteoarthritis in rats, and also its effect on the systematic levels of IL-2,4,7, BMPs 2,4,7, CRP and Fetuin-A. 30 male Sprague Dawley rats were separated in two groups where post-traumatic osteoarthritis was induced surgically by Anterior Cruciate Ligament Transection and the transection of the Medial Collateral Ligament of the right knee. In the Control Group, only surgical intervention took place. In Fetuin Group, along with the induction of osteoarthritis, a single dose of bovine fetuin was administrated intra-articularly intra-operatively in 5 and 8 weeks of the experimental protocol. Both groups were examined for 8 weeks. The levels of interleukins,
Segmental bone transport (SBT) using an external fixator is currently a standard treatment for large-diameter bone defects at the donor site with low morbidity. However, long-term application of the device is needed for bone healing. In addition, patients who received SBT treatment sometimes fail to show bone repair and union at the docking site, and require secondary surgery. The objective of this study was to investigate whether a single injection of recombinant human
The development of functional biomaterials scaffolds for bone tissue engineering applications includes the control of specific biological and mechanical parameters that are involved in the growth of bone tissue in a way that mimics the physiological process of healing bone defects. Here, we report on the development of composite scaffolds made from biodegradable natural and synthetic biomaterials with characteristic architectural features, functionalized with the osteoinductive growth factor
Objectives. Effects of insulin-like growth factor 1 (IGF1), fibroblast growth
factor 2 (FGF2) and
Bone has a remarkable capacity to heal. However, in some instances the amount of bone which is needed to heal exceeds its healing capacity. Due to reported issues with current treatments there is continued research into alternative approaches with a view to producing an off the shelf alternative to the gold standard autologous bone transplants. The current investigated the use of a chitosan/hydroxyapatite scaffold, which was used to covalently