Human Bone Morphogenetic Protein-2 Research Articles

BMP-2 inhibits lung metastasis of osteosarcoma: an early investigation using an orthotopic model.

BackgroundBone morphogenetic proteins (BMPs), members of the TGF-β superfamily, are known to regulate cell proliferation, differentiation, apoptosis, chemotaxis, and angiogenesis. BMPs also participate in the development of most tissues and organs in vertebrates. Recombinant human (rh) BMPs, such as rhBMP-2, rhBMP-4, and rhBMP-7, have been recently approved to augment spinal fusion and recalcitrant long-bone non-unions because of their equivalent or superior efficacy to autogenous bone graft in enhancing bony fusion. Nonetheless, the use of BMPs is contraindicated in surgery for bone tumors because of concerns that this anabolic growth factor may cause tumor proliferation. However, we have repeatedly reported that BMP-2 is effective in inducing osteogenic differentiation of a subpopulation of osteosarcoma (OSA) cells that acquire stem cell attributes and are capable of reconstituting tumor masses, which in turn suppress the malignancy of the bone tumor.Methods3×105/20 µL human OSA 143B cells were inoculated into 5–6 weeks old BABL/c nude mice to establish orthotopic OSA. X-ray device was used to monitor the developed tumors in animals. Necropsy was performed and the pathology of lung metastasis were tested by Haemotoxylin and Eosin. Moreover, bone formation induced by rhBMP-2 was investigated through micro-computed tomography. In addition, immunohistochemistry staining was used to evaluate the tumorigenicity and growth of OSA cells after rhBMP-2 treatment.ResultsIn the present study, we established an orthotopic model of OSA by inoculating 143B cells into BABL/c mice, which resulted in a tumor occurrence rate of 100%. Following the treatment with rhBMP-2, lung metastasis, which contributes to poor prognosis, was significantly restricted, indicating an additional aspect of rhBMP-2 to suppress expansion of OSA. Concurrently, our micro-computed tomography and radiographic analyses showed that rhBMP-2 reduced the invasion of tumor cells into adjacent bone tissue, which in turn helped to preserve the integrity of the affected bone tissue. Finally, the growth of Ki-67-positive cells and those cells that express high levels of aldehyde dehydrogenase (ALDHbr) was found to be inhibited in the developed tumors.ConclusionOn the basis of these results, we conclude that rhBMP-2 can impede the malignancy of OSA by reducing lung metastasis of the tumor. Induction of the tumor cells by rhBMP-2 also helps to preserve the impaired skeleton. These results imply that BMP-2 or BMP-2-mimetic drugs, if properly combined with traditional therapies, may provide a new therapeutic option for the treatment of OSA.

Localized low-dose rhBMP-2 is effective at promoting bone regeneration in mandibular segmental defects.

At least 26% of recent battlefield injuries are to the craniomaxillofacial (CMF) region. Recombinant human bone morphogenetic protein 2 (rhBMP-2) is used to treat CMF open fractures, but several complications have been associated with its use. This study tested the efficacy and safety of a lower (30% recommended) dose of rhBMP-2 to treat mandibular fractures. rhBMP-2 delivered via a polyurethane (PUR) and hydroxyapatite/β-tricalcium phosphate (Mastergraft®) scaffold was evaluated in a 2 cm segmental mandibular defect in minipigs. Bone regeneration was analyzed at 4, 8, and 12 weeks postsurgery using clinical computed tomography (CT) and rhBMP-2, and inflammatory marker concentrations were analyzed in serum and surgery-site drain effluent. CT scans revealed that pigs treated with PUR-Mastergraft® + rhBMP-2 had complete bone bridging, while the negative control group showed incomplete bone-bridging (n = 6). Volumetric analysis of regenerated bone showed that the PUR-Mastergraft® + rhBMP-2 treatment generated significantly more bone than control by 4 weeks, a trend that continued through 12 weeks. Variations in inflammatory analytes were detected in drain effluent samples and saliva but not in serum, suggesting a localized healing response. Importantly, the rhBMP-2 group did not exhibit an excessive increase in inflammatory analytes compared to control. Treatment with low-dose rhBMP-2 increases bone regeneration capacity in pigs with mandibular continuity defects and restores bone quality. Negative complications from rhBMP-2, such as excessive inflammatory analyte levels, were not observed. Together, these results suggest that treatment with low-dose rhBMP-2 is efficacious and may improve safety when treating CMF open fractures. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1491-1503, 2019.

Mechanisms of Bone Morphogenetic Protein-7 Protective Effects Against Cold Ischemia-Induced Renal Injury in Rats

Deceased donor kidneys are exposed to cold ischemic insult which makes them particularly susceptible to the effects of cold ischemic injury during hypothermic preservation resulting in high rates of delayed graft function. Bone morphogenetic protein-7 (BMP-7) is a valuable reagent in the field of tissue regeneration and preservation under ischemic conditions. Following these insights, we investigated the effect of recombinant human BMP-7 (rhBMP-7) on graft preservation during cold ischemia.The study was conducted on an experimental model of kidney cold ischemia in rats. Kidneys were perfused with University of Wisconsin (UW) saline solution, rhBMP-7, or rhBMP-7 + UW, and exposed to cold ischemia for 6, 12, and 24 hours.In tubular epithelial cells of kidneys perfused with rhBMP-7 and rhBMP-7+UW solution, the expression of BMP-7 and E-cadherin was observed after 24 hours of cold ischemia. In kidneys not perfused with rhBMP-7, high expression of transforming growth factor-β and α-smooth muscle actin was found. Also, in kidneys perfused with rhBMP-7 solution, statistically higher levels of Smad1, Smad5, and Smad8 messenger RNA expressions were proven.BMP-7 maintains the morphology of kidney tissue better than UW solution during 24 hours of cold ischemia. BMP-7 prevents epithelial to mesenchymal transformation and consequently maintains epithelial phenotype of tubular cells.

Effects of Tunable Keratin Hydrogel Erosion on Recombinant Human Bone Morphogenetic Protein 2 Release, Bioactivity, and Bone Induction.

Recombinant human bone morphogenetic protein 2 (rhBMP-2) delivery from collagen sponges for bone formation is an important clinical example of growth factors in tissue engineering. Side effects from rhBMP-2 burst release and rapid collagen resorption have led to investigation of alternative carriers. Here, keratin carriers with tunable erosion rates were formulated by varying disulfide crosslinking via ratios of oxidatively (keratose) to reductively (kerateine) extracted keratin. In vitro rhBMP-2 bioactivity increased with kerateine content, reaching levels greater than with collagen. Heterotopic bone formation in a mouse model depended on the keratin formulation, highlighting the importance of the growth factor carrier.

The Clinical Application of Recombinant Human Bone Morphogenetic Protein 7 for Reconstruction of Alveolar Cleft: 10 Years' Follow-Up

The purpose of this study was to report on a 10-year assessment after the application of recombinant human bone morphogenetic protein 7 (rhBMP-7) for the reconstruction of alveolar clefts. This study was conducted as a prospective phase II clinical trial on 9 unilateral and 2 bilateral alveolar clefts that received rhBMP-7 (Osigraft; Stryker Biotech, UK). The mean age of thepatients at surgery was 10.4years. At 6months postoperatively, occlusal radiographs were taken to evaluate bone formation at the cleft site. Patients were followed within the routine cleft care pathway for 10years to monitor the impact of bone morphogenetic protein 7 on orthodontic treatments and maxillary growth. Radiographs were taken according to the standard cleft care protocol. The radiographic assessment of the unilateral cleft lip and palate cases suggested good bone formation with a Kindelan score of grade 1 or 2. The bilateral alveolar cleft cases had a score of grade 3 or 4, indicating failure or partial failure. The children with successful grafts underwent a routine orthodontic follow-up without incident. The maxillary growth appeared to be similar to that in cases grafted with autogenous bone. No long-term complications and no abnormal pattern of bone formation were detected. The study provides unique evidence on the long-term safety of rhBMP-7 when applied at the area of skeletal immaturity for the reconstruction of alveolar clefts in children.

Association Between Recombinant Human Bone Morphogenetic Proteins and Postoperative Opioid Use in Lumbar Fusion Procedure Patients: A Propensity Score-Matched Analysis

Little is known about the effectiveness of recombinant human bone morphogenetic proteins (rhBMPs) in reducing the demand for opioids after surgery. We investigated the association between rhBMP use and the likelihood of achieving opioid independence and changes in opioid demand in the first postoperative year. Using the Multi-Payer Claims Database from 2007 to 2010, patients aged >20 years who had undergone a degenerative disc disease-indicated lumbar fusion procedure and had had ≥1 opioid prescription in the 3 months before surgery were identified. Propensity score matching (1:1) of rhBMP-exposed and rhBMP-unexposed patients was used to mitigate confounding. The outcomes of interest were opioid independence and decreases in opioid doses in morphine equivalent units, assessed at 3-6 and 9-12 months after the procedure. Logistic regression and analysis of covariance models were used. The data from 318 patients were analyzed. Most patients were women (61%) and aged <65 years (68%). Few had achieved opioid independence at 3-6 (n=71; 22.3%) or 9-12 (n= 115; 36.2%) months postoperatively. During the 3-6-month window, the rhBMP group reduced their opioid use rates (estimated mean difference.-28.4 vs.-19.5; P= 0.69) and achieved opioid independence (21.4% vs. 23.3%; odds ratio, 0.92; 95% confidence interval, 0.54-1.56; P= 0.74) at rates that were statistically comparable to their matched comparators. Similar patterns were observed during the 9-12-month window. We found no evidence to suggest that rhBMP use during spinal fusion procedures is associated with either the discontinuation or decrease of opioid analgesic therapy. The continued opioid use after surgery warrants further clinical and research attention.

Inhibition of osteoblastic Smurf1 promotes bone formation in mouse models of distinctive age-related osteoporosis

Bone morphogenetic protein (BMP) signaling is essential for osteogenesis. However, recombinant human BMPs (rhBMPs) exhibit large inter-individual variations in local bone formation during clinical spinal fusion. Smurf1 ubiquitinates BMP downstream molecules for degradation. Here, we classify age-related osteoporosis based on distinct intraosseous BMP-2 levels and Smurf1 activity. One major subgroup with a normal BMP-2 level and elevated Smurf1 activity (BMP-2n/Smurf1e) shows poor response to rhBMP-2 during spinal fusion, when compared to another major subgroup with a decreased BMP-2 level and normal Smurf1 activity (BMP-2d/Smurf1n). We screen a chalcone derivative, i.e., 2-(4-cinnamoylphenoxy)acetic acid, which effectively inhibits Smurf1 activity and increases BMP signaling. For BMP-2n/Smurf1e mice, the chalcone derivative enhances local bone formation during spinal fusion. After conjugating to an osteoblast-targeting and penetrating oligopeptide (DSS)6, the chalcone derivative promotes systemic bone formation in BMP-2n/Smurf1e mice. This study demonstrates a precision medicine-based bone anabolic strategy for age-related osteoporosis.

Controllable and durable release of BMP-2-loaded 3D porous sulfonated polyetheretherketone (PEEK) for osteogenic activity enhancement.

Polyetheretherketone (PEEK) is ideal for dental and orthopedic applications because its mechanical properties are similar to cortical bones. However, its inherent inert ability hinders its clinical applications. In this work, bone morphogenetic protein-2 (BMP-2) was immobilized onto the sulfonated PEEK (SPEEK) using lyophilization technology. The surface morphologies of the samples were analyzed by field-emission scanning electron microscopy (FE-SEM), and the chemical compositions were analyzed by energy-dispersive X-ray spectrometry (EDS). The release content of BMP-2 of the samples immersed in the PBS (pH = 7.4) was detected by a human BMP-2 ELISA kit. The results indicated that controllable and durable BMP-2 release was accomplished due to the three-dimensional (3D) network of sulfonated PEEK. The in vitro cellular experiments showed that the BMP-2-immobilized samples significantly enhanced the initial adhesion and spreading of rat bone mesenchymal stem cells (rBMSCs). Moreover, the collagen secretion, extracellular matrix mineralization and ALP activity were also improved. Thus, the BMP-2-immobilized samples greatly promoted the osteogenic differentiation of rBMSCs, which revealed that BMP-2 immobilization paves the way for the use of PEEK in clinical applications.

Bioactive Tape With BMP-2 Binding Peptides Captures Endogenous Growth Factors and Accelerates Healing After Anterior Cruciate Ligament Reconstruction

Background: The anterior cruciate ligament (ACL) has poor regenerative capacity, and an injury leads to loss of function, limiting quality of life and increasing the incidence of osteoarthritis. Surgical interventions can stabilize the joint and improve functional recovery. The delivery of growth factors (GFs) enhances the healing process; however, this is complex in its regulation, is high in costs, has side effects, and can only be accomplished with supraphysiological concentrations and thus is currently not clinically feasible. However, the immobilization of a patient’s endogenous GFs in biomaterials can overcome these problems. Purpose: To develop a method to capture endogenous bone morphogenetic protein–2 (BMP-2) and ultimately show enhanced ACL healing in vivo using this novel methodology. Study Design: Controlled laboratory study. Methods: BMP-2 binding peptides were synthetized, purified, and immobilized on polycaprolactone (PCL) films. The affinity between the peptide and human BMP-2 (hBMP-2) was confirmed with immunofluorescence and enzyme-linked immunosorbent assay. The C2C12 Luc reporter cell line was used to confirm the bioactivity of immobilized BMP-2. For in vivo experiments, the same functionalization technology was applied to the commercially available Polytape, and the functionalized tape was sutured together with the graft used for ACL reconstruction in rats. Each animal underwent reconstruction with either native Polytape (n = 3) or Polytape with BMP-2 binding peptides (n = 3). At 2 and 6 weeks after surgery, the graft was assessed by histology and micro–computed tomography. Results: The covalent immobilization of the peptide in PCL was successful, allowing the peptide to capture hBMP-2, which remained bioactive and led to the osteogenic differentiation of C2C12. In vivo experiments confirmed the potential of the Polytape functionalized with the BMP-2 binding peptide to capture endogenous BMP-2, leading to enhanced bone formation inside the femoral and tibial tunnels and ultimately improving the graft’s quality. Conclusion: The incorporation of BMP-2 binding peptides into materials used for ACL reconstruction can capture endogenous hBMP-2, which enhances the healing process inside the bone tunnels. Clinical Relevance: These results demonstrate the potential of using synthetic peptides to endow biomaterials with novel biological functions, namely to capture and immobilize endogenous GFs.

Friday, September 28, 2018 4:05 PM–5:05 PM abstracts: basic science of spinal fusion: 235. Peptide amphiphile nanoscaffolds potentiates the delivery of rh-BMP2 in a rabbit spine fusion model

BACKGROUND CONTEXT Recombinant human bone morphogenetic protein (rhBMP-2) is an effective biologic to mitigate pseudoarthrosis after spinal fusion surgery. However, supraphysiologic doses of rhBMP-2 can lead to significant complications, necessitating development of a product that can reduce its therapeutic dose. From our previous work, we have established peptide amphiphile (PA) nanofibers containing rhBMP-2 binding motifs as a potential material to achieve this aim in a rat proof-of-concept model. PURPOSE The purpose of this study was to assess and validate the efficacy of peptide amphiphile (PA) nanoscaffold containing a rhBMP-2 binding motif for spinal fusion in a more stringent animal model, with the intent of reducing the amount of exogenous growth factor necessary to achieve successful fusion. METHODS Female New Zealand white rabbits underwent bilateral PLF at L4-L5 utilizing sub-therapeutic doses of 30 µg or 60µg rhBMP-2 per animal (15 or 30µg per side). Rabbits received one of three delivery systems: ACS, PA/ACS, or PA/ACS particles. Spine fusion and bone regeneration were assessed using radiography, manual palpation, and microCT imaging. Manual palpation was performed by three blinded investigators using an established scoring system: 0=no fusion, 1=unilateral fusion, 2=bilateral fusion. Spines that average a score ≥1 were considered fused. One-way ANVOA with Tukey's post-hoc was used to evaluate for differences in fusion scoring among groups with continuous variables. RESULTS The delivery systems utilizing PA (PA/ACS or PA/collagen particles) achieved 100% fusion at both the 30µg or 60µg rhBMP-2 doses. This rate was significantly higher than the fusion rate observed using ACS alone at either the 30µg (0%, p CONCLUSIONS Although ACS is the only FDA approved rhBMP-2 delivery vehicle for spine fusion, its inefficient retention of the growth factor requires supraphysiologic doses to achieve consistent fusion. Our work demonstrates that a BMP-2-binding PA nanofiber scaffold used in conjunction with ACS or collagen particles can significantly enhance rhBMP-2 action, thereby reducing the necessary rhBMP-2 dose and potentially mitigating the side effects associated with high doses of the growth factor. Future studies will establish the lower limit of the rhBMP-2 dose required to elicit fusion in the rabbit model.

Evaluation of BMP-2 Enhances the Osteoblast Differentiation of Human Amnion Mesenchymal Stem Cells Seeded on Nano-Hydroxyapatite/Collagen/Poly(l-Lactide).

Background: The aim of this study is to evaluate the effects of recombinant human bone morphogenetic protein 2 (rhBMP-2), human amnion mesenchymal stem cells (hAMSCs), and nanohydroxyapatite/collagen/poly(l-lactide) (nHAC/PLA) in tissue engineering to provide potential approaches for periodontal bone regeneration. Methods: hAMSCs were isolated from discarded amniotic membrane samples and cultured in vitro. Alkaline phosphatase (ALP) staining and alizarin red staining were performed to evaluate the osteoblast (OB) differentiation ability of hAMSCs. Three groups were divided: the experimental group (cells transfected with pcDNA3.1-rhBMP-2), the blank group (cells without gene transfection), and the control group (cells transfected with empty plasmid). RT-PCR and western blot were used to examine whether rhBMP-2 has been successfully expressed. 3-(4,5)-dimethylthiahiazol(-z-y1)-3,5-di-phenytetrazo-liumromide assay (MTT) was done to detect the effect of rhBMP-2 on hAMSCs seeded on nHAC/PLA. ALP activity, mineral formation assay, calcium, phosphate and osteocalcin (OCN) content, and OCN and RUNX2 expression of hAMSCs were detected to evaluate osteogenic differentiation capability of rhBMP-2 on hAMSCs seeded on nHAC/PLA. Results: hAMSCs exhibited intense ALP staining, obvious calcium deposition, and mineralization nodules, and rhBMP-2 were highly expressed in the experimental group. The proliferation of the hAMSCs with rhBMP-2 on nHAC/PLA was significantly higher than the cells without rhBMP-2, and the cells all increased in a time-dependent manner. rhBMP-2 significantly increased the OCN and phosphate content, mineral formation, ALP activity, osteogenic biomarkers OCN, and Runx2, and decreased calcium content in hAMSCs seeded on the nHAC/PLA scaffold. Conclusions: This finding demonstrated that hAMSCs has an ideal OB differentiation ability. rhBMP-2 facilitates the proliferation and osteogenesis of hAMSCs. The nHAC/PLA could act as a good scaffold for hAMSCs seeding, proliferation, and osteogenic differentiation. The application of rhBMP-2, nHAC/PLA, and hAMSCs in tissue engineering may offer promising possibilities for periodontal bone regeneration.

Hydrolytically Labile Linkers Regulate Release and Activity of Human Bone Morphogenetic Protein-6.

Release of growth factors while simultaneously maintaining their full biological activity over a period of days to weeks is an important issue in controlled drug delivery and in tissue engineering. In addition, the selected strategy to immobilize growth factors largely determines their biological activity. Silica surfaces derivatized with glycidyloxy propyl trimethoxysilane and poly(glycidyl methacrylate) brushes yielded epoxide-functionalized surfaces onto which human bone morphogenetic protein-6 (hBMP-6) was immobilized giving stable secondary amine bonds. The biological activity of hBMP-6 was unleashed by hydrolysis of the surface siloxane and ester bonds. We demonstrate that this type of labile bonding strategy can be applied to biomaterial surfaces with relatively simple and biocompatible chemistry, such as siloxane, ester, and imine bonds. Our data indicates that the use of differential hydrolytically labile linkers is a versatile method for functionalization of biomaterials with a variety of growth factors providing control over their biological activity.

Biological effects of BMP7 on small-cell lung cancer cells and its bone metastasis

Small-cell lung cancer(SCLC) is typically fatal if untreated. It is characterized by early and widespread metastases, and has the ability to rapidly develop resistance to chemotherapy. Bone morphogenetic protein7(BMP7), a member of the BMP family of signaling molecules, has been implicated in various types of cancer, particularly prostate cancer and breast cancer. However, there is little knowledge of the function of BMP7 in SCLC. The aim of the present study was to investigate the biological function of recombinant human (rh)BMP7 on SCLC cells and the underlying molecular basis for this regulatory mechanism. The effect of rhBMP7 on SCLC cell lines and associated signaling pathways was investigated. Results suggested that rhBMP7 significantly inhibited the proliferation, motility and invasion of SBC-3 and SBC-5 cells. However, rhBMP7 exhibited no effect on the apoptosis of SBC-5 cells, but promoted apoptosis of SBC-3 cells. Furthermore, cell cycle analysis revealed that rhBMP7 was able to increase the proportion of cells in G1phase and decrease the S phase proportion. Total and membrane BMP receptor(BMPR)IA and BMPRIB were highly expressed in SBC-5 cells, whereas cytoplasmic BMPRIA and BMPRIB expression was higher in SBC-3 cells. However, activinA receptor typeI expression was higher in SBC-3 cells in total and cytoplasmic proteins. Furthermore, following stimulation with rhBMP7, Smad2, Smad4 and p21 were downregulated. We hypothesized that rhBMP7 inhibited the progressiveness of SCLC cells by inducing G1phase arrest and inhibiting Sphase entry. The results of the present study indicated that BMP7 serves a key function in regulating the progression of SCLC.

Effect of Bone Morphogenetic Protein-2/Hydroxyapatite on Ankle Fusion with Bone Defect in an Rabbit Animal Model

Category: Basic Sciences/Biologics Introduction/Purpose: Revision arthrodesis surgery after total ankle arthroplasty failure has a problem related with large bone defect management after implant removal. Although autogenous bone is a standard method for the reconstruction of bone defects, it often causes complications such as wound problem, infection, fracture, hematoma, persistent pain and a limited amount of bone.Recombinant human bone morphogenetic protein-2 (rhBMP-2) has a powerful osteoinductive ability, it plays essential roles in bone regeneration strategies. The purpose of this study is to evaluate the substitute ability of rhBMP-2 for autologous bone in rabbit ankle fusion model with distal tibia bone defect. Methods: Bone defect (5 X 5 X 8 mm) was created in the distal tibia between media and lateral malleolus include cartilage. Ankle fusion was performed by 1 cannulated screw from lateral malleolus and various treatments on bone defect. Fifteen male white New Zealand rabbits were divided into three groups of 5 animals on each groups dependent on treatment method; Group I (control, no treatment into defect), II (autogenous bone treatment), III (rhBMP-2/ hydroxyapatite treatment). Bone formation on defect and the union of the ankle joint was evaluated by X-ray, micro-CT scan and histological at 8 weeks and 12 weeks postoperatively. Results: X-ray and micro-CT shows higher bone formation on defect in group II and III than group I at 8 weeks and 12 weeks. According to histological results, completely union between distal tibia and talus in group III, partially union in group II and nonunion in group I. Conclusion: These findings indicate the BMP-2/Hydroxyapatite has a bone fusion effect comparable to autogenous bone, and suggest that rhBMP-2/Hydroxyapatite can be used to substitute for autogenous bone in ankle fusion with a bone defect, thereby overcome the limitations of autogenous bone.

Demineralized Dentin Matrix as a Carrier of Recombinant Human Bone Morphogenetic Proteins: &lt;i&gt;in Vivo&lt;/i&gt; Study

Demineralized Dentin Matrix as a Carrier of Recombinant Human Bone Morphogenetic Proteins: &lt;i&gt;in Vivo&lt;/i&gt; Study

Biomaterials for the Delivery of Growth Factors and Other Therapeutic Agents in Tissue Engineering Approaches to Bone Regeneration.

Bone fracture followed by delayed or non-union typically requires bone graft intervention. Autologous bone grafts remain the clinical “gold standard”. Recently, synthetic bone grafts such as Medtronic's Infuse Bone Graft have opened the possibility to pharmacological and tissue engineering strategies to bone repair following fracture. This clinically-available strategy uses an absorbable collagen sponge as a carrier material for recombinant human bone morphogenetic protein 2 (rhBMP-2) and a similar strategy has been employed by Stryker with BMP-7, also known as osteogenic protein-1 (OP-1). A key advantage to this approach is its “off-the-shelf” nature, but there are clear drawbacks to these products such as edema, inflammation, and ectopic bone growth. While there are clinical challenges associated with a lack of controlled release of rhBMP-2 and OP-1, these are among the first clinical examples to wed understanding of biological principles with biochemical production of proteins and pharmacological principles to promote tissue regeneration (known as regenerative pharmacology). After considering the clinical challenges with such synthetic bone grafts, this review considers the various biomaterial carriers under investigation to promote bone regeneration. This is followed by a survey of the literature where various pharmacological approaches and molecular targets are considered as future strategies to promote more rapid and mature bone regeneration. From the review, it should be clear that pharmacological understanding is a key aspect to developing these strategies.

Combination therapy of canine osteosarcoma with canine bone marrow stem cells, bone morphogenetic protein and carboplatin in an in vivo model.

Osteosarcoma (OSA) is the most common malignant bone cancer in children and dogs. The therapeutic protocols adopted for dogs and humans are very similar, involving surgical options such as amputation. Besides surgical options, radiotherapy and chemotherapy also are adopted. However, hematologic, gastrointestinal and renal toxicity may occur because of chemotherapy treatments. Recent study clearly showed that mesenchymal stem cells (MSCs) combined with recombinant human bone morphogenetic protein (rhBMP-2) may be associated with decreases of the tumorigenic potential of canine OSA. The aim of this study was to analyse the efficacy of chemotherapy with carboplatin and rhBMP-2 with MSCs in a canine OSA in vivo model. Canine OSA cells were implanted in mice Balb-c/nude with MSCs, rhBMP-2 and carboplatin. Flow cytometry and PCR for markers involved in tumour suppression pathways were analysed. Results showed that the combination of MSCs and rhBMP-2 reduced tumour mass and infiltration of neoplastic cells in tissues more efficiently than carboplatin alone. Thus it was demonstrated that the use of rhBMP-2 and MSCs, in combination with conventional antineoplastic, may be an efficient treatment strategy.

Engineered Coatings for Titanium Implants To Present Ultralow Doses of BMP-7.

The ongoing research to improve the clinical outcome of titanium implants has resulted in the implemetation of multiple approches to deliver osteogenic growth factors accelerating and sustaining osseointegration. Here we show the presentation of human bone morphogenetic protein 7 (BMP-7) adsorbed to titanium discs coated with poly(ethyl acrylate) (PEA). We have previously shown that PEA promotes fibronectin organization into nanonetworks exposing integrin- and growth-factor-binding domains, allowing a synergistic interaction at the integrin/growth factor receptor level. Here, titanium discs were coated with PEA and fibronectin and then decorated with ng/mL doses of BMP-7. Human mesenchymal stem cells were used to investigate cellular responses on these functionalized microenvironments. Cell adhesion, proliferation, and mineralization, as well as osteogenic markers expression (osteopontin and osteocalcin) revealed the ability of the system to be more potent in osteodifferentiation of the mesenchymal cells than combinations of titanium and BMP-7 in absence of PEA coatings. This work represents a novel strategy to improve the biological activity of titanium implants with BMP-7.

Solubilization and renaturation of biologically active human bone morphogenetic protein-4 from inclusion bodies

Biologically active human bone morphogenetic protein-4 (hBMP-4) was successfully produced in a prokaryotic host. For this aim, hBMP-4 cDNA was cloned in Escherichia coli (E. coli) and the protein was produced in a non-active aggregated form. After washing and solubilization, in vitro refolding of the rhBMP-4 monomer was performed using rapid dilution. In this study, different refolding conditions were tested for the dimerization of rhBMP-4 by one-factor-at-a-time variation. The dimerization process was found to be sensitive to pH, protein concentration and the presence of aggregation suppressors. In contrast, redox conditions and ionic strength did not impact refolding as expected. The dimer was separated from the remaining monomer, aggregates and host cell contaminants in a single step using cation-exchange membrane chromatography. The rhBMP-4 dimer produced in E. coli was biologically active as demonstrated by its capability to induce trophoblast differentiation and primitive streak induction of human pluripotent stem cells (hPSCs).

The Posterior Use of BMP-2 in Cervical Deformity Surgery Does Not Result in Increased Early Complications: A Prospective Multicenter Study.

Study Design:Prospective cohort study.Objectives:To describe the rate of short-term complications following the posterior use of recombinant human bone morphogenetic protein–2 (rhBMP-2) in cervical deformity (CD) surgery.Methods:CD patients from 2013 to 2015 were enrolled in a prospective, multicenter database. Patients were divided into those receiving rhBMP-2 (BMP) and no rhBMP-2 (NOBMP). The relationship between BMP use, demographic variables surgical variables, radiographic parameters and complications was evaluated.Results:A total of 100 patients (47 BMP, 53 NOBMP) were included. Follow-up time averaged 7.6 months (range 3-12 months). An average of 13.6mg of BMP was used per person with 1.49 mg per level. Compared with the NOBMP group, patients in the BMP group were older (P = .03). BMP was more commonly used in patients that and had longer prior fusions (6.0 vs 2.5, P < .01). There were no differences between groups with regards to a history of surgery, Charlson Comorbidity Index, estimated blood loss, operation time, fusion levels, and surgical approach. The maintenance of radiographic parameters at 6-month follow-up was similar. There were no differences in terms of total complication incidence, total complications per person, major complications per person or any specific complication. Linear regression and Pearson correlation analysis did not reveal any strong r2 values (r2 = 0.09, 0.08, 0.06) between the use of BMP and complications (major or operative).Conclusions:BMP use was not directly associated with an increased incidence of early complications in this prospective cohort of operative adult CD patients. Its use was associated with increased number of levels instrumented and fused.