Effectiveness of rhBMP-2 association to autogenous, allogeneic, and heterologous bone grafts.

Proteins with osteoinductive potential, especially recombinant human bone morphogenetic protein (rhBMP)-2, have large effects on cell growth and their differentiation. The aim of this study was to assess repair of bone defects in rat calvaria with different types of grafts associated with rhBMP-2, through immunohistochemistry and micro computed tomography (CT) analyses. A total of 35 male Wistar rats were selected, each weighing ~250 g, with a waiting period of 6 weeks from the creation of the defect to the sacrifice, and divided into five groups (n = 7): autograft plus 5 µg rhBMP-2 (AuG/BMP-2); allograft plus 5 µg rhBMP-2 (AlG/BMP-2); xenograft (heterologous) plus 5 µg rhBMP-2 (XeG/BMP-2); 5 µg rhBMP-2 (BMP-2) and the control group (n = 7). The micro CT reveal that all groups associating different bone grafts with BMP-2 showed increased bone formation compared to the control. The immunostaining show that osteocalcin and bone sialoprotein were higher in groups with BMP-2 than control group; BMP was high expressed in AuG/BMP-2, AlG/BMP-2, and BMP-2; vascular endothelial growth factor (VEGF) was more expressed in groups with BMP-2; VEGF-R2 was low to moderate in AuG/BMP-2, XeG/BMP-2, and BMP-2, predominantly moderate in AlG/BMP-2 and low in the control; CD-31 was predominantly moderate in AuG/BMP-2, AlG/BMP-2, and XeG/BMP-2, low to moderate in BMP-2 and low in the control. The results revealed that rhBMP-2 improved bone repair when administered alone, or when associated with different bone grafts.

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.

Collagen sponge and rhBMP-2 improve socket healing in rats treated with zoledronic acid.

The aim of the present study was to evaluate the possible use of a commercial absorbed collagen sponge and bone morphogenetic protein (BMP) for the prevention of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in rats. Twenty rats received intraperitoneal injections of 0.1-mg/kg of zoledronic acid three times a week for eight weeks before the extraction of both maxillary first molars after eight weeks. A collagen sponge (experimental group 1) and a collagen sponge with recombinant human BMP-2 (experimental group 2) were applied to the right extraction sockets of ten rats each. The 20 left extraction sockets (control groups 1 and 2) were left unprotected. After eight weeks, all rats were euthanized. Macroscopic analysis, micro-computed tomography (CT) analysis, and histological analysis were performed. There was a significant difference in the bone density between the control and experimental groups on micro-CT analysis. Impaired healing of the extraction sockets, indicating BRONJ, was observed in 80% of control group 1, 90% of control group 2, 30% of experimental group 1, and 20% of experimental group 2. The collagen sponge with/without BMP used for protecting the extraction socket had the potential for a positive effect in reducing the incidence of bisphosphonate-related osteonecrosis of the jaw in rats.

The Use of Bone Morphogenetic Protein in Spinal Transforaminal Lumbar Interbody Fusion: Our Experience.

OBJECTIVE: Since its introduction and FDA approval, rhBMP-2 has been adopted by spine surgeons as a substitute for ICBG in numerous spinal fusion techniques. As broad clinical use increased, reports on potential complications associated with rhBMP-2 also increased. We provide our experience with TLIF using rhBMP-2 or ICBG in an entirely Hispanic population. METHODS: This was a 2-year retrospective study of 67 patients, with 26 in the rhBMP-2 group and 41 in the ICBG group, who underwent TLIF. Pertinent information was obtained through review of the medical records documenting complications, intraoperative times, and EBL, among other things. RESULTS: There were 28 post-operative complications with 15 (53.6%) in the ICBG group and 13 (46.4%) in the rhBMP-2 group. The average EBL was 572.3 mL (SD: 411.8) in the ICBG group and 397.9 mL (SD: 312.2) in the rhBMP-2 group. The average intraoperative time was 243.1 minutes (SD: 79.5) in the ICBG group and 226.5 minutes (SD: 64.7) in the rhBMP-2 group. Fifty-two patients underwent open TLIF and 15 patients underwent MI TLIF. The average EBL was 571.2 mL (SD: 375.3) in the open TLIF group and 228.3 mL (SD: 299.3) in the MI-TLIF group. The average intraoperative time was 241.0 minutes (SD: 76.0) for patients in the open TLIF group and 218.8 minutes (SD: 65.0) for those in the MI-TLIF group. There were no new cancer events at any of the 2-year follow-up visits. RESULTS: Our results suggest that the safety profile of rhBMP-2 may be inferior to that of ICBG, rejecting the possibility of ICBG being replaced by rhBMP-2 as the gold standard for spinal fusion.

Collagen sponge and rhBMP-2 improve socket healing in rats treated with zoledronic acid

Abstract The aim of the present study was to evaluate the possible use of a commercial absorbed collagen sponge and bone morphogenetic protein (BMP) for the prevention of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in rats. Twenty rats received intraperitoneal injections of 0.1-mg/kg of zoledronic acid three times a week for eight weeks before the extraction of both maxillary first molars after eight weeks. A collagen sponge (experimental group 1) and a collagen sponge with recombinant human BMP-2 (experimental group 2) were applied to the right extraction sockets of ten rats each. The 20 left extraction sockets (control groups 1 and 2) were left unprotected. After eight weeks, all rats were euthanized. Macroscopic analysis, micro-computed tomography (CT) analysis, and histological analysis were performed. There was a significant difference in the bone density between the control and experimental groups on micro-CT analysis. Impaired healing of the extraction sockets, indicating BRONJ, was observed in 80% of control group 1, 90% of control group 2, 30% of experimental group 1, and 20% of experimental group 2. The collagen sponge with/without BMP used for protecting the extraction socket had the potential for a positive effect in reducing the incidence of bisphosphonate-related osteonecrosis of the jaw in rats.

Three-Dimensional Upper Lip and Nostril Sill Changes After Cleft Alveolus Reconstruction Using Autologous Bone Grafting Versus Recombinant Human Bone Morphogenetic Protein-2.

Cleft alveolus in patients with unilateral complete cleft lip and palate has been alternatively reconstructed with recombinant human bone morphogenetic protein (rhBMP)-2. However, its effects on upper lip and nostril sill anatomy are not known. Thus, the objective of this investigation was to assess and compare upper lip and nostril sill changes after cleft alveolus reconstruction with autologous bone from the iliac crest region and rhBMP-2. Patients were randomly allocated into 2 groups. In group 1, autologous bone from the iliac crest region was used to fill the cleft alveolus (n = 4), and in group 2, rhBMP-2 was used to fill the cleft alveolus (n = 8). Preoperatively and at one after the surgery, computerized tomography (CT) was performed. Reformatted CT imaging was used to perform cephalometric linear measurements of the upper lip and nostril sill regions. Inter- and intragroup data of the pre and postoperative reformatted CT measurements of the upper lip and nostril sill regions did not show differences (P >0.05) in cutaneous upper lip height and projection, nostril sill elevation, and subnasale projection. There were no significant upper lip and nostril sill anatomical changes after cleft alveolus reconstruction using autologous bone grafting and rhBMP-2.

Minimally traumatic alveolar ridge augmentation with a tunnel injectable thermo-sensitive alginate scaffold.

UNLABELLED: Injectable bone substitutes and techniques have been developed for use in minimally invasive procedures for bone augmentation. OBJECTIVE: To develop a novel injectable thermo-sensitive alginate hydrogel (TSAH) as a scaffold to induce bone regeneration, using a minimally invasive tunnelling technique. MATERIAL AND METHODS: An injectable TSAH was prepared from a copolymer solution of 8.0 wt% Poly(N-isopropylacrylamide) (PNIPAAm) and 8.0 wt% AAlg-g-PNIPAAm. In vitro properties of the material, such as its microstructure and the sustained release of recombinant human bone morphogenetic protein-2 (rhBMP-2), were investigated. Then, with the subperiosteal tunnelling technique, this material, carrying rhBMP-2, was injected under the labial periosteum of the maxillary anterior alveolar ridge in a rabbit model. New bone formation was evaluated by means of X-ray, micro-computed tomography (micro-CT), fluorescence labelling, histological study, and immunohistochemistry study. RESULTS: The material exhibited good injectability and thermo-irreversible properties. SEM showed an interconnected porous microstructure of the TSAH. The result of ALP activity indicated sustained delivery of BMP-2 from the TSAH from days 3 to 15. In a rabbit model, both TSAH and TSAH/rhBMP-2 induced alveolar ridge augmentation. The percentage of mineralised tissue in the TSAH/rhBMP-2 group (41.6 ± 3.79%) was significantly higher than in the TSAH group (31.3 ± 7.21%; p < 0.05). The density of the regenerating tissue was higher in the TSAH/rhBMP-2 group than in the other groups (TSAH group, positive control, blank control; p < 0.05). CONCLUSIONS: The TSAH provided convenient handling properties for clinical application. To some extent, TSAH could induce ridge augmentation and mineral deposition, which can be enhanced when combined with rhBMP-2 for a minimally invasive tunnelling injection.

Neuropeptide Y, substance P, and human bone morphogenetic protein 2 stimulate human osteoblast osteogenic activity by enhancing gap junction intercellular communication.

Bone homeostasis seems to be controlled by delicate and subtle "cross talk" between the nervous system and "osteo-neuromediators" that control bone remodeling. The purpose of this study was to evaluate the effect of interactions between neuropeptides and human bone morphogenetic protein 2 (hBMP2) on human osteoblasts. We also investigated the effects of neuropeptides and hBMP2 on gap junction intercellular communication (GJIC). Osteoblasts were treated with neuropeptide Y (NPY), substance P (SP), or hBMP2 at three concentrations. At various intervals after treatment, cell viability was measured by the MTT assay. In addition, cellular alkaline phosphatase (ALP) activity and osteocalcin were determined by colorimetric assay and radioimmunoassay, respectively. The effects of NPY, SP and hBMP on GJIC were determined by laser scanning confocal microscopy. The viability of cells treated with neuropeptides and hBMP2 increased significantly in a time-dependent manner, but was inversely associated with the concentration of the treatments. ALP activity and osteocalcin were both reduced in osteoblasts exposed to the combination of neuropeptides and hBMP2. The GJIC of osteoblasts was significantly increased by the neuropeptides and hBMP2. These results suggest that osteoblast activity is increased by neuropeptides and hBMP2 through increased GJIC. Identification of the GJIC-mediated signal transduction capable of modulating the cellular activities of bone cells represents a novel approach to studying the biology of skeletal innervation.

Use of rhBMP-2 to reconstruct a severely atrophic mandible: a modified approach.

This study reports the case of a patient with a severely resorbed mandible who was treated without a bone graft, using short implants, internal rigid fixation, rhBMP-2 and ß-tricalcium phosphate. A 76-year-old woman, with a severely resorbed mandible (less than 3mm), reported a history of nearly 25 years of complete edentulism and consecutive treatment failures, with total bilateral exposed inferior alveolar nerves and complete bone resorption of the inferior border in some areas. The treatment of choice was the placement of a 2.0mm thick unilock bone plate (MatrixMandible, Synthes Maxillofacial, Paoli, PA, USA), to reinforce the mandible. Eight short implants with a regular platform (Nobel Biocare, Goteborg, Sweden) were placed: three on the external oblique line on both sides and two on the symphysis. In order to augment mandible height and coat the exposed thread of the anterior implants, rhBMP-2 (Infuse Bone, Meditronic Sofamor Danek, Memphis, TN, USA) and ß-tricalcium phosphate (Cerasorb; Curasan, Kleinostheim, Germany) were used. Four 1.3 mmL miniplates were placed to support the graft. 14 months after surgery, the patient was satisfied and had excellent function without complications.

Influence of low-level laser associated with osteogenic proteins recombinant human BMP-2 and Hevea brasiliensis on bone repair in Wistar rats.

This study analyzed the newly formed bone tissue after application of recombinant human BMP-2 (rhBMP-2) and P-1 (extracted from Hevea brasiliensis) proteins, 2 weeks after the creation of a critical bone defect in male Wistar rats treated or not with a low-intensity laser (GaAlAs 780 nm, 60 mW of power, and energy density dose of 30 J/cm(2)). The animals were divided into two major groups: (1) bone defect plus low-intensity laser treatment and (2) bone defect without laser irradiation. The following subgroups were also analyzed: (a) 5 µg of pure rhBMP-2; (b) 5 µg of pure P-1 fraction; (c) 5 µg of rhBMP-2/monoolein gel; (d) 5 µg of P-1 fraction/monoolein gel; (e) pure monoolein gel. Comparisons of the groups receiving laser treatment with those that did not receive laser irradiation show differences in the areas of new bone tissue. The group treated with 5 µg of rhBMP-2 and laser irradiation was not significantly different (P >0.05) than the nonirradiated group that received the same treatment. The irradiated, rhBMP-2/monoolein gel treatment group showed a lower area of bone formation than the nonirradiated, rhBMP-2/gel monoolein treatment group (P < 0.001). The area of new bone tissue in the other nonirradiated and irradiated groups was not significantly different (P > 0.05). Furthermore, the group that received the 5 µg of rhBMP-2 application showed the greatest bone formation. We conclude that the laser treatment did not interfere with the area of new bone tissue growth and that the greatest stimulus for bone formation involved application of the rhBMP-2 protein.

Bone repair investigation using rhBMP-2 and angiogenic protein extracted from latex.

BACKGROUND: The aim of this work was to study the new bone tissue formation after bone morphogenetic protein type 2 (rhBMP-2) and P-1 application, using 5 and 10 µg of each, combined to a material carrier, in critical bone defects. METHODS: It was used 70 Wistar rats (male, ∼250 g) that were divided in 10 groups with seven animals on each. Groups are the following: critical bone defect only, pure monoolein gel, 5 µg of pure P-1, 5 µg of pure rhBMP-2, 5 µg of P-1/monoolein gel, 5 µg of rhBMP-2/monoolein gel, 10 µg of pure P-1, 10 µg of pure rhBMP-2, 10 µg of P-1/monoolein gel, 10 µg of rhBMP-2/monoolein gel. Animals were sacrificed after 4 weeks of the surgical procedure and the bone samples were submitted to histological, histomorphometrical, and immunohistochemical evaluations. RESULTS: Animals treated with pure P-1 protein, in both situations with 5 µg and 10 µg, had no significant difference (P > 0.05) for new bone formation; other groups treated with 10 µg were statistically significant (P < 0.05) among themselves and when compared with groups in which it was inserted the monoolein gel or critical bone defect only (P < 0.05). In the group involving the 10 µg rhBMP-2/monoolein gel association, it was observed an extensive bone formation, even when compared with the same treatment without the gel carrier. CONCLUSION: Using this experimental animal model, more new bone tissue was found when it was inserted the rhBMP-2, especially when this protein was combined to the vehicle, and this process seems to be dose dependent.

Effects of the combination of low-level laser irradiation and recombinant human bone morphogenetic protein-2 in bone repair.

Low-level laser irradiation (LLLI) and recombinant human bone morphogenetic protein type 2 (rhBMP-2) have been used to stimulate bone formation. LLLI stimulates proliferation of osteoblast precursor cells and cell differentiation and rhBMP-2 recruits osteoprogenitor cells to the bone healing area. This in vivo study evaluated the effects of LLLI and rhBMP-2 on the bone healing process in rats. Critical bone defects were created in the parietal bone in 42 animals, and the animals were divided into six treatment groups: (1) laser, (2) 7 µg of rhBMP-2, (3) laser and 7 µg of rhBMP-2, (4) 7 µg of rhBMP-2/monoolein gel, (5) laser and 7 µg rhBMP-2/monoolein gel, and (6) critical bone defect controls. A gallium-aluminum-arsenide diode laser was used (wavelength 780 nm, output power 60 mW, beam area 0.04 cm(2), irradiation time 80 s, energy density 120 J/cm(2), irradiance 1.5 W/cm(2)). After 15 days, the calvarial tissues were removed for histomorphometric analysis. Group 3 defects showed higher amounts of newly formed bone (37.89%) than the defects of all the other groups (P < 0.05). The amounts of new bone in defects of groups 1 and 4 were not significantly different from each other (24.00% and 24.75%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). The amounts of new bone in the defects of groups 2 and 5 were not significantly different from each other (31.42% and 31.96%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). Group 6 defects had 14.10% new bone formation, and this was significantly different from the amounts in the other groups (P < 0.05). It can be concluded that LLLI administered during surgery effectively accelerated healing of critical bone defects filled with pure rhBMP-2, achieving a better result than LLLI alone or the use of rhBMP-2 alone.

Evaluation of maxillary alveolar reconstruction using a resorbable collagen sponge with recombinant human bone morphogenetic protein-2 in cleft lip and palate patients.

INTRODUCTION: A resorbable collagen matrix with recombinant human bone morphogenetic protein (rhBMP-2) was compared with traditional iliac crest bone graft for the closure of alveolar defects during secondary dental eruption. METHODS: Sixteen patients with unilateral cleft lip and palate, aged 8 to 12 years, were selected and randomly assigned to group 1 (rhBMP-2) or group 2 (iliac crest bone graft). Computed tomography was performed to assess both groups preoperatively and at months 6 and 12 postoperatively. Bone height and defect volume were calculated through Osirix Dicom Viewer (Pixmeo, Apple Inc.). Overall morbidity was recorded. RESULTS: Preoperative and follow-up examinations revealed progressive alveolar bone union in all patients. For group 1, final completion of the defect with a 65.0% mean bone height was detected 12 months postoperatively. For group 2, final completion of the defect with an 83.8% mean bone height was detected 6 months postoperatively. Dental eruption routinely occurred in both groups. Clinical complications included significant swelling in three group 1 patients (37.5%) and significant donor-site pain in seven group 2 patients (87.5%). CONCLUSIONS: For this select group of patients with immature skeleton, rhBMP-2 therapy resulted in satisfactory bone healing and reduced morbidity compared with traditional iliac crest bone grafting.

Effect of recombinant human bone morphogenetic protein-2 on bone formation in the acute distraction osteogenesis of rat mandibles.

BACKGROUND: Distraction osteogenesis (DO) is a method of producing new bone directly from the osteotomy site by gradual traction of the divided bone fragments. AIM: The purpose of the present study was to evaluate histomorphometrically whether acute DO would constitute a viable alternative to the conventional continuous distraction treatment and also to verify the capacity of a recombinant human BMP (rhBMP-2) associated with monoolein gel to stimulate bone formation in the acute distraction process. MATERIALS AND METHODS: Forty-eight Wistar rats were assigned to three groups: Group 1, treated at a conventional continuous distraction rate (0.5 mm/day), Group 2, treated with acute distraction of 2.5 mm at the time of the surgical procedure, and Group 3, subjected to acute distraction associated with rhBMP-2. The animals from each experimental group were killed at the end of the second or fourth post-operative weeks and the volume fraction of newly formed bone trabeculae was estimated in histological images by a differential point-counting method. RESULTS: The results showed that after 2 and 4 weeks, bone volumes in the rhBMP-2 group were significantly higher than in the other groups (P<0.05), but no significant difference was observed in the volume fraction of newly formed bone between the continuous and acute DO groups. CONCLUSION: In conclusion, the study indicates that rhBMP-2 can enhance the bone formation at acute DO, which may potentially reduce the treatment period and complications related to the distraction procedure.