Repair of alveolar clefts with recombinant human bone morphogenetic protein (rhBMP-2) in patients with clefts

Controlled release of granulocyte colony-stimulating factor enhances osteoconductive and biodegradable properties of Beta-tricalcium phosphate in a rat calvarial defect model

Autologous bone grafts remain the gold standard for the treatment of congenital craniofacial disorders; however, there are potential problems including donor site morbidity and limitations to the amount of bone that can be harvested. Recent studies suggest that granulocyte colony-stimulating factor (G-CSF) promotes fracture healing or osteogenesis. The purpose of the present study was to investigate whether topically applied G-CSF can stimulate the osteoconductive properties of beta-tricalcium phosphate (β-TCP) in a rat calvarial defect model. A total of 27 calvarial defects 5 mm in diameter were randomly divided into nine groups, which were treated with various combinations of a β-TCP disc and G-CSF in solution form or controlled release system using gelatin hydrogel. Histologic and histomorphometric analyses were performed at eight weeks postoperatively. The controlled release of low-dose (1 μg and 5 μg) G-CSF significantly enhanced new bone formation when combined with a β-TCP disc. Moreover, administration of 5 μg G-CSF using a controlled release system significantly promoted the biodegradable properties of β-TCP. In conclusion, the controlled release of 5 μg G-CSF significantly enhanced the osteoconductive and biodegradable properties of β-TCP. The combination of G-CSF slow-release and β-TCP is a novel and promising approach for treating pediatric craniofacial bone defects.

Tissue engineering for plastic surgeons: a primer

A central tenet of reconstructive surgery is the principle of "replacing like with like." However, due to limitations in the availability of autologous tissue or because of the complications that may ensue from harvesting it, autologous reconstruction may be impractical to perform or too costly in terms of patient donor-site morbidity. The field of tissue engineering has long held promise to alleviate these shortcomings. Scaffolds are the structural building blocks of tissue-engineered constructs, akin to the extracellular matrix within native tissues. Commonly used scaffolds include allogenic or xenogenic decellularized tissue, synthetic or naturally derived hydrogels, and synthetic biodegradable nonhydrogel polymeric scaffolds. Embryonic, induced pluripotent, and mesenchymal stem cells also hold immense potential for regenerative purposes. Chemical signals including growth factors and cytokines may be harnessed to augment wound healing and tissue regeneration. Tissue engineering is already clinically prevalent in the fields of breast augmentation and reconstruction, skin substitutes, wound healing, auricular reconstruction, and bone, cartilage, and nerve grafting. Future directions for tissue engineering in plastic surgery include the development of prevascularized constructs and rationally designed scaffolds, the use of stem cells to regenerate organs and tissues, and gene therapy.

BMP-2 expression correlates with local failure in head and neck squamous cell carcinoma

OBJECTIVE

Preclinical data show that exogenous administration of recombinant human bone morphogenetic protein-2 (rhBMP-2) to human oral carcinoma cell lines increases pathogenicity using a nude mouse model. The objectives of this study are to (1) describe the characteristics of baseline protein expression of BMP-2 in head and neck squamous cell carcinomas (HNSCC) and (2) determine if BMP-2 expression level correlates with worse oncologic outcomes.

STUDY DESIGN

Retrospective analysis of previously harvested patient samples.

SETTING

Academic medical center.

SUBJECTS

In total, 149 patients with oral cavity, oropharynx, larynx, and hypopharynx HNSCC treated between January 1, 1997, and December 31, 2004.

METHODS

A tissue microarray of HNSCC was assembled and immunohistochemistry for BMP-2 performed. Staining was quantified using a standardized scoring system. Specimens were dichotomized into high or low expression level. Statistical analyses using log-rank, Wilcoxon, and Fisher exact test were performed for associations between BMP-2 protein level and clinicopathologic features and patient survival.

RESULTS

BMP-2 expression at any level was noted in 146 of 149 (98%) of samples. Tumors with high BMP-2 expression had higher rates of local failure compared with low-expressing tumors (17.3% vs 6.3%; P = .04). There was no significant association for BMP-2 expression level with tumor location, T stage, N stage, overall survival, regional failure, or distant failure.

CONCLUSION

Head and neck squamous cell carcinomas with high baseline BMP-2 protein level are associated with higher rates of local recurrence. These data have important implications for using rhBMP-2 in tissue engineering reconstructive approaches in the setting of cancer-related defects.

Functionalization of scaffolds with chimeric anti-BMP-2 monoclonal antibodies for osseous regeneration

Recent studies have demonstrated the ability of murine anti-BMP-2 monoclonal antibodies (mAb) immobilized on an absorbable collagen sponge (ACS) to mediate de novo bone formation, a process termed antibody-mediated osseous regeneration (AMOR). The objectives of this study were to assess the efficacy of a newly generated chimeric anti-BMP-2 mAb in mediating AMOR, as well as to evaluate the suitability of different biomaterials as scaffolds to participate in AMOR. Chimeric anti-BMP-2 mAb was immobilized on 4 biomaterials, namely, titanium microbeads (Ti), alginate hydrogel, macroporous biphasic calcium phosphate (MBCP) and ACS, followed by surgical implantation into rat critical-size calvarial defects. Animals were sacrificed after 8 weeks and the degree of bone fill was assessed using micro-CT and histomorphometry. Results demonstrated local persistence of chimeric anti-BMP-2 mAb up to 8 weeks, as well as significant de novo bone regeneration in sites implanted with chimeric anti-BMP-2 antibody immobilized on each of the 4 scaffolds. Ti and MBCP showed the highest volume of bone regeneration, presumably due to their resistance to compression. Alginate and ACS also mediated de novo bone formation, though significant volumetric shrinkage was noted. In vitro assays demonstrated cross-reactivity of chimeric anti-BMP-2 mAb with BMP-4 and BMP-7. Immune complex of anti-BMP-2 mAb with BMP-2 induced osteogenic differentiation of C2C12 cells in vitro, involving expression of RUNX2 and phosphorylation of Smad1. The present data demonstrated the ability of chimeric anti-BMP-2 mAb to functionalize different biomaterial with varying characteristics to mediate osteogenesis.

Co-encapsulation of anti-BMP2 monoclonal antibody and mesenchymal stem cells in alginate microspheres for bone tissue engineering

Recently, it has been shown that tethered anti-BMP2 monoclonal antibodies (mAbs) can trap BMP ligands and thus provide BMP inductive signals for osteo-differentiation of progenitor cells. The objectives of this study were to: (1) develop a co-delivery system based on murine anti-BMP2 mAb-loaded alginate microspheres encapsulating human bone marrow mesenchymal stem cells (hBMMSCs); and (2) investigate osteogenic differentiation of encapsulated stem cells in alginate microspheres in vitro and in vivo. Alginate microspheres of 1 ± 0.1 mm diameter were fabricated with 2 × 10(6) hBMMSCs per mL of alginate. Critical-size calvarial defects (5 mm diameter) were created in immune-compromised mice and alginate microspheres preloaded with anti-BMP mAb encapsulating hBMMSCs were transplanted into defect sites. Alginate microspheres pre-loaded with isotype-matched non-specific antibody were used as the negative control. After 8 weeks, micro CT and histologic analyses were used to analyze bone formation. In vitro analysis demonstrated that anti-BMP2 mAbs tethered BMP2 ligands that can activate the BMP receptors on hBMMSCs. The co-delivery system described herein, significantly enhanced hBMMSC-mediated osteogenesis, as confirmed by the presence of BMP signal pathway-activated osteoblast determinants Runx2 and ALP. Our results highlight the importance of engineering the microenvironment for stem cells, and particularly the value of presenting inductive signals for osteo-differentiation of hBMMSCs by tethering BMP ligands using mAbs. This strategy of engineering the microenvironment with captured BMP signals is a promising modality for repair and regeneration of craniofacial, axial and appendicular bone defects.

Volumetric analysis of simulated alveolar cleft defects and bone grafts using cone beam computed tomography

BACKGROUND

Cone beam computed tomography allows for a significantly lower radiation dose than conventional computed tomographic scans, with generation of accurate images of the maxillofacial skeleton. The authors investigated its accuracy in the volumetric analysis of alveolar cleft defects and simulated bone grafts.

METHODS

Five simulated alveolar clefts were created using a burr drill in three dry pediatric skulls and filled with simulated bone grafts. Pregrafting and postgrafting cone beam computed tomographic scanning of skulls was performed using specialized imaging software. The authors compared actual volumes of the simulated bone grafts obtained using a water displacement technique with scan-derived volumes of both the grafts and the defects.

RESULTS

The average of the five simulated bone grafts calculated by cone beam computed tomography scanning was 0.380 ml, which was lower than their mean volume of 0.392 ml calculated by water displacement. The percentage difference between measurements ranged from 2.9 to 8.6 percent (mean, 4.86 percent). The mean of the simulated defects of 0.399 ml derived from scanning was higher than the actual mean volume of 0.392 ml derived by water displacement. The mean difference in defect comparison was 2.52 percent. There was no statistically significant difference between real volume and scan-derived graft and defect volume.

CONCLUSIONS

Cone beam computed tomography calculation of simulated alveolar cleft and bone graft volume is precise and accurate. The volume of bone graft needed to fill alveolar defects can be accurately predicted using volume measurements of the bony defect. These findings further validate its use in the perioperative assessment of alveolar grafting.

Injection and adhesion palatoplasty: a preliminary study in a canine model

BACKGROUND

Raising mucoperiosteal flaps in traditional palatoplasty impairs mid-facial growth. Hyaluronic acid-based hydrogels have been successfully tested for minimally invasive craniofacial bone generation in vivo as carriers of bone morphogenetic protein-2 (BMP-2). We aimed to develop a novel flapless technique for cleft palate repair by injecting a BMP-2 containing hydrogel.

MATERIAL AND METHODS

Dog pups with congenital cleft palate were either non-treated (n=4) or treated with two-flap palatoplasty (n=6) or with the proposed injection/adhesion technique (n=5). The experimental approach was to inject a hyaluronic acid-based hydrogel containing hydroxyapatite and BMP-2 subperiosteally at the cleft palate margins of pups aged six weeks. At week ten, a thin strip of the medial edge mucosa was removed and the margins were closed directly. Occlusal photographs and computed tomography (CT) scans were obtained up to week 20.

RESULTS

Four weeks after the gel injection the cleft palate margins had reached the midline and engineered bone had enlarged the palatal bones. Removal of the medial edge mucosa and suturing allowed complete closure of the cleft. Compared to traditional palatoplasty, the injection/adhesion technique was easier, and the post-surgical recovery was faster. CT on week 20 revealed some overlapping or "bending" of palatal shelves in the two-flap repair group, which was not observed in the experimental nor control groups.

CONCLUSION

A minimally invasive technique for cleft palate repair upon injectable scaffolds in a dog model of congenital cleft palate is feasible. Results suggest better growth of palatal bones. This represents an attractive clinical alternative to traditional palatoplasty for cleft palate patients.

Precise control of osteogenesis for craniofacial defect repair: the role of direct osteoprogenitor contact in BMP-2-based bioprinting

BACKGROUND

Success with bone morphogenetic protein-2 (BMP-2) has been widely reported in the osseous reconstruction of large calvarial defects. These efforts have required enormous doses of BMP-2 and are not sufficiently refined to facilitate the detail-oriented repair required for intricate craniofacial structures. We have previously shown that inkjet-based bioprinting technologies allow for precisely customized low-dose protein patterns to induce spatially regulated osteogenesis. Here, we investigate the importance of direct contact between bioprinted BMP-2 and the dura mater (a source of osteoprogenitors) in mediating calvarial healing.

METHODS

Five-millimeter osseous defects were trephinated in mouse parietal bones (N=8). Circular acellular dermal matrix (ADM) implants were prepared such that 1 semicircle of 1 face per implant was printed with BMP-2 bio-ink. These implants were then placed ink-toward (N=3) or ink-away (N=5) from the underlying dura mater. After 4 weeks, osteogenesis was assessed in each of the 4 possible positions (BMP-2-printed area toward dura, BMP-2-printed area away from dura, unprinted area toward dura, and unprinted area away from dura) by faxitron.

RESULTS

The BMP-2-printed portion of the ADM generated bone covering an average of 66.5% of its surface area when it was face-down (printed surface directly abutting dura mater). By comparison, the BMP-2-printed portion of the ADM generated bone covering an average of only 21.3% of its surface area when it was face-up (printed surface away from dura). Similarly, the unprinted portion of the ADM generated an average of only 18.6% osseous coverage when face-down and 18.4% when face-up.

CONCLUSIONS

We have previously shown that inkjet-based bioprinting has the potential to significantly enhance the role of regenerative therapies in craniofacial surgery. This technology affords the precise control of osteogenesis necessary to reconstruct this region's intricate anatomical architecture. In the present study, we demonstrate that direct apposition of BMP-2-printed ADM to a source of osteoprogenitor cells (in this case dura mater) is necessary for bio-ink-directed osteogenesis to occur. These results have important implications for the design of more complex bioprinted osseous structures.

Bone morphogenetic proteins in craniofacial surgery: current techniques, clinical experiences, and the future of personalized stem cell therapy

Critical-size osseous defects cannot heal without surgical intervention and can pose a significant challenge to craniofacial reconstruction. Autologous bone grafting is the gold standard for repair but is limited by a donor site morbidity and a potentially inadequate supply of autologous bone. Alternatives to autologous bone grafting include the use of alloplastic and allogenic materials, mesenchymal stem cells, and bone morphogenetic proteins. Bone morphogenetic proteins (BMPs) are essential mediators of bone formation involved in the regulation of differentiation of osteoprogenitor cells into osteoblasts. Here we focus on the use of BMPs in experimental models of craniofacial surgery and clinical applications of BMPs in the reconstruction of the cranial vault, palate, and mandible and suggest a model for the use of BMPs in personalized stem cell therapies.

Bone regeneration in artificial jaw cleft by use of carbonated hydroxyapatite particles and mesenchymal stem cells derived from iliac bone

Objectives of the Study. Cleft lip and palate (CLP) is a prevalent congenital anomaly in the orofacial region. Autogenous iliac bone grafting has been frequently employed for the closure of bone defects at the jaw cleft site. Since the related surgical procedures are quite invasive for patients, it is of great importance to develop a new less invasive technique. The aim of this study was to examine bone regeneration with mesenchyme stem cells (MSCs) for the treatment of bone defect in artificially created jaw cleft in dogs. Materials and Methods. A bone defect was prepared bilaterally in the upper incisor regions of beagle dogs. MSCs derived from iliac bone marrow were cultured and transplanted with carbonated hydroxyapatite (CAP) particles into the bone defect area. The bone regeneration was evaluated by standardized occlusal X-ray examination and histological observation. Results. Six months after the transplantation, perfect closure of the jaw cleft was achieved on the experimental side. The X-ray and histological examination revealed that the regenerated bone on the experimental side was almost equivalent to the original bone adjoining the jaw cleft. Conclusion. It was suggested that the application of MSCs with CAP particles can become a new treatment modality for bone regeneration for CLP patients.

Antibody-mediated osseous regeneration: a novel strategy for bioengineering bone by immobilized anti-bone morphogenetic protein-2 antibodies

Bone regeneration often requires harvesting of autologous bone with significant potential morbidity and cost. Recombinant human bone morphogenetic protein (rhBMP)-2 has been approved by the U.S. Food and Drug Administration for specific regenerative indications. However, administration of exogenous growth factors has many drawbacks. The objective of the present proof-of-concept study was to determine whether immobilized anti-BMP-2 antibodies (Abs) could capture endogenous BMP-2 in local sites to mediate osteogenesis, a strategy we refer to as antibody-mediated osseous regeneration (AMOR). We have generated a murine anti-BMP-2 monoclonal antibody library, which was tested along with commercially available Abs in vitro and in vivo for their ability to mediate AMOR. In vitro studies demonstrated that only some anti-BMP-2 Abs tested formed immune complexes with BMP-2, which can bind to BMP cellular receptor, whereas other BMP-2/anti-BMP-2 complexes failed to bind. To investigate whether anti-BMP-2 Abs were able to mediate AMOR in vivo, anti-BMP-2 Abs were immobilized on absorbable collagen sponge (ACS) and surgically placed in rat calvarial defects. Microcomputed tomography analysis of live animals at 2, 4, and 6 weeks demonstrated that some anti-BMP-2 Abs immobilized on ACS mediated significant bone regeneration, whereas other clones did not mediate any bone regeneration. In situ BMP-2 and osteocalcin expression was investigated by immunohistochemistry. Results demonstrated higher BMP-2 and osteocalcin expression in sites with increased bone regeneration. Results provide first evidence for the ability of anti-BMP2 Abs to form an immune complex with endogenous BMP-2 and mediate bone regeneration in vivo, suggesting a promising therapeutic method for tissue engineering.

Treatment effects of rhBMP-2 on invasiveness of oral carcinoma cell lines

OBJECTIVE

To determine if recombinant human bone morphogenetic protein-2 (rhBMP-2) has biological effects on the invasiveness of human oral squamous cell carcinoma (OSCCA) cell lines.

STUDY DESIGN

Laboratory investigation using six human OSCCA cell lines, with three cell lines having baseline gene expression of BMP-2 and three cell lines without baseline gene expression of BMP-2.

METHODS

The invasiveness of each cell line was measured using a matrigel invasion assay with or without stimulation by rhBMP-2. A tumor metastasis quantitative PCR array was used to establish whether observed findings from the invasion assay correlated to changes in gene expression.

RESULTS

There was a significant increase in tumor cell invasion in response to rhBMP-2 in all BMP-2 positive cell lines but no change in the cell lines that did not express the BMP-2 gene. Quantitative PCR revealed that changes in gene expression were distinctly different based on the baseline gene expression of BMP-2 and favored a more metastatic genotype in the BMP-2-positive cells.

CONCLUSIONS

Recombinant human BMP-2 has an adverse biological effect on invasiveness of human OSCCA cell lines in vitro. This adverse effect is dependent on the baseline gene expression of BMP-2. Changes in expression of genes involved with tumor metastasis correlated to the invasion assay findings. These data raise concern for the safe application of rhBMP-2 for reconstruction of bone defects in oral cancer patients.

[Oro-maxillofacial bone tissue engineering combining biomaterials, stem cells, and gene therapy]

Improvements have been made in regenerative medicine, due to the development of tissue engineering and cellular therapy. Bone regeneration is an ambitious project, leading to many applications involving skull, maxillofacial, and orthopaedic surgery. Scaffolds, stem cells, and signals support bone tissue engineering. The scaffold physical and chemical properties promote cell invasion, guide their differentiation, and enable signal transmission. Scaffold may be inorganic or organic. Their conception was improved by the use of new techniques: self-assembled nanofibres, electrospinning, solution-phase separation, micropatterned hydrogels, bioprinting, and rapid prototyping. Cellular biology processes allow us to choose between embryonic stem cells or adult stem cells for regenerative medicine. Finally, communication between cells and their environment is essential; they use various signals to do so. The study of signals and their transmission led to the discovery and the use of Bone Morphogenetic Protein (BMP). The development of cellular therapy led to the emergence of a specific field: gene therapy. It relies on viral vectors, which include: retroviruses, adenoviruses and adeno-associated vectors (AAV). Non-viral vectors include plasmids and lipoplex. Some BMP genes have successfully been transfected. The ability to control transfected cells and the capacity to combine and transfect many genes involved in osseous healing will improve gene therapy.

Reconstruction of the alveolar cleft: can growth factor-aided tissue engineering replace autologous bone grafting? A literature review and systematic review of results obtained with bone morphogenetic protein-2

The alveolar cleft in patients with clefts of lip, alveolus and palate (CLAP) is usually reconstructed with an autologous bone graft. Harvesting of autologous bone grafts is associated with more or less donor site morbidity. Donor site morbidity could be eliminated if bone is fabricated by growth factor-aided tissue engineering. The objective of this review was to provide an oversight on the current state of the art in growth factor-aided tissue engineering with regard to reconstruction of the alveolar cleft in CLAP. Medline, Embase and Central databases were searched for articles on bone morphogenetic protein 2 (BMP-2), bone morphogenetic protein 7, transforming growth factor beta, platelet-derived growth factor, insulin-like growth factor, fibroblast growth factor, vascular endothelial growth factor and platelet-rich plasma for the reconstruction of the alveolar cleft in CLAP. Two-hundred ninety-one unique search results were found. Three articles met our selection criteria. These three selected articles compared BMP-2-aided bone tissue engineering with iliac crest bone grafting by clinical and radiographic examinations. Bone quantity appeared comparable between the two methods in patients treated during the stage of mixed dentition, whereas bone quantity appeared superior in the BMP-2 group in skeletally mature patients. Favourable results with BMP-2-aided bone tissue engineering have been reported for the reconstruction of the alveolar cleft in CLAP. More studies are necessary to assess the quality of bone. Advantages are shortening of the operation time, absence of donor site morbidity, shorter hospital stay and reduction of overall cost.

Bilateral orbitozygomatic reconstruction with tissue-engineered bone

Critical defects of the craniomaxillofacial region and long bones are often treated with bone grafts and vascularized osteocutaneous free flaps. These lengthy operations may be associated with considerable donor site morbidity and often have suboptimal functional and aesthetic results. The allure of providing an exact replica of a missing bone that incorporates to become indistinguishable from self, has the capacity to heal and grow, is resistant to infection, and with minimal morbidity is a "holy grail" to all surgeons who work with bone. This is a report of a 14-year-old adolescent boy with Treacher Collins syndrome whose bilateral orbitozygomatic defects were treated with engineered bone made from a combination of human bone allograft, adipose-derived mesenchymal stem cells, bone morphogenic protein-2, and periosteal grafts. This single-stage reconstruction was followed by an exuberant amount of postoperative swelling that persisted for 3 weeks. He had slight lid malposition postoperatively as well but has had no long-term negative effects from the surgery. His reconstruction has remained stable during a 6-month follow-up, and a recent biopsy of the engineered bone demonstrated healthy, lamellar bone. These data are the first to demonstrate revitalization of large volume allograft bone in humans and have positive implications for craniofacial bone tissue engineering. The combination of adipose-derived stem cells, bone morphogenic protein-2, bone allograft, and periosteum may provide an alternative method to both osteocutaneous free flaps and large structural allografts with less morbidity and improved long-term results.

Effect of psoralen on bone formation

To compare the amount of new bone and bone cells produced by psoralen in collagen matrix to that produced by collagen matrix in vivo. Eighteen bone defects, 5 mm by 10 mm were created in the parietal bone of nine New Zealand White rabbits. Six defects were grafted with psoralen mixed with collagen matrix. Six defects were grafted with collagen matrix alone (negative control--collagen) and six were left empty (negative control--empty). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Quantitative analysis of new bone formation and bone cells were made on 100 sections (50 sections for each group) using image analysis. A total of 454% more new bone was present in defects grafted with psoralen in collagen matrix than those grafted with collagen matrix. No bone was formed in the negative control--empty group. The amount of bone forming osteoblasts was also significantly greater in the psoralen group than the negative control--collagen group. Psoralen in collagen matrix has the effect of increasing new bone formation locally in vivo. Psoralen in collagen matrix can be developed as a bone graft material.

Alveolar cleft defect closure with iliac bone graft, rhBMP-2 and rhBMP-2 with zygoma shavings: Comparative study

Aim:

To present the outcome measures of the use of iliac bone graft, rhBMP-2 and rhBMP-2 with zygoma shavings in alveolar cleft defect closure.

Materials and Methods:

Retrospective analysis of details of treated alveolar defect cases (5-10 years during January 2008–December 2010) from records with 4 months follow-up in accordance with the inclusion criteria.

Predictor Variables:

Type of graft used (iliac crest graft/rhBMP-2/rhBMP-2 with zygoma shaving).

Outcome Variables:

Duration of the operation, blood loss, postoperative drugs used, donor site morbidity, efficiency of bone deposition (radiologically) at 4 months.

Statistics:

Descriptive statistics, one-way ANOVA. P < 0.05 was taken as significant.

Results:

Forty two cases met the inclusion criteria. Mean efficiency of bone deposition was 89.97 ± 4.79%. Mean efficiency of bone formation in rhBMP-2 (n=13), rhBMP-2 with zygoma shavings (n=9) and iliac crest graft (n=20) was 89.42%, 95.38% and 87.91%, respectively (P=0.000). Drugs usage and postoperative morbidity differed significantly between groups (P < 0.05).

Conclusion:

The use of rhBMP-2 evades the need for additional surgery and overcomes the postoperative morbidity that is associated with the conventional iliac grafting technique. The rhBMP-2 with zygoma shavings showed maximum benefits.

Routine Use of Recombinant Human Bone Morphogenetic Protein-2 in Posterior Fusions of the Pediatric Spine: Safety Profile and Efficacy in the Early Postoperative Period

BACKGROUND:

Previous studies using recombinant human bone morphogenetic protein-2 (rhBMP-2) in the adult lumbar spine have shown consistently good results. There have been no pediatric case series.

OBJECTIVE:

To determine the safety and efficacy of rhBMP-2 use in posterior instrumented fusions of the pediatric population.

METHODS:

A retrospective review of 19 consecutive pediatric patients who underwent posterior occiptocervical, cervical, thoracic, lumbar, or lumbosacral spine fusion from October 1, 2007, to June 30, 2008, at Texas Children's Hospital was performed. The average age was approximately 12 years old (range, 9 months to 20 years). The minimum follow-up was 17 months (average of 19 months, range: 17–25 months), with computed tomography (CT) evaluation and grading of fusion by an independent radiologist at 3 months after surgery.

RESULTS:

The average CT grade was 3, indicating bilateral bridging bone. No pseudoarthroses or loss of correction was identified clinically or radiographically at 3 months and latest follow-up. There was one complication of bony overgrowth and restenosis of the spinal canal necessitating reoperation, and two superficial wound infections. There were no deep wound infections.

CONCLUSION:

Early outcomes using rhBMP-2 in the pediatric population show that it is a safe and efficacious adjunct to posterior spine fusions of the occipitocervical, cervical, thoracic, lumbar, and lumbosacral spine. It dependably results in the development of stable bridging bone at 3 months after surgery with good maintenance of correction and stability in long-term follow-up. Lessons learned from the case of unexpected bony overgrowth are discussed.

Effect of Buguzhi (Psoralea corylifolia fruit) extract on bone formation

The objective of the study is to compare the amount of new bone produced by Buguzhi (Psoralea corylifolia fruit) extract in collagen matrix to that produced and collagen matrix in vivo. Eighteen bone defects, 5 mm by 10 mm, were created in the parietal bone of 9 New Zealand white rabbits. Six defects were grafted with Buguzhi extract mixed with collagen matrix. Six defects were grafted with collagen matrix alone (positive control) and 6 were left empty (negative control). Animals were sacrificed on day 14 and the defects were dissected and prepared for histological assessment. Quantitative analysis of new bone formation and bone cells was made on 100 sections (50 sections for each group) using image analysis. A total of 275% more new bone was present in defects grafted with Buguzhi extract in collagen matrix than those grafted with collagen matrix. No bone was formed in the negative control group. The amount of bone cells was also significantly greater in the Buguzhi group than in the positive control group. To conclude, Buguzhi extract in collagen matrix has the effect of increasing new bone formation locally in vivo. Buguzhi extract in collagen matrix can be used as a bone graft material.

Management of tibial non-union with tricalcium phosphate and BMP 7

We present the case of a 30-year-old woman who was referred with an established tibial non-union with a bone defect following a spiral fracture of the tibia. Initial attempts at union with intramedullary fixation and then autograft were unsuccessful. We achieved union by debriding the fibrous tissue and packing the defect with Bone Morphogenetic Protein 7 (Osigraft, Stryker, UK) and a tricalcium phosphate bone void filler (Calstrux, Stryker, UK). We did not use any additional surgical fixation and the patient was supported in an aircast boot.

Bone morphogenetic proteins in craniomaxillofacial surgery

Craniomaxillofacial surgery has many indications for bone regeneration and augmentation, ranging from socket preservation to reconstruction of large skeletal defects. The discovery of bone morphogenetic proteins (BMPs) as osteoinductive agents and the subsequent development of commercially available recombinant forms of BMPs have offered the potential to replace traditional grafting techniques with de novo bone formation. Extensive preclinical and clinical research has focused on establishing the safety and efficacy of using recombinant BMPs to regenerate bone in the facial skeleton. This article reviews the development and current scientific basis behind the use of these new biologics.

Effect of bio-oss collagen and collagen matrix on bone formation

Objective:

to compare the amount of new bone produced by Bio-Oss^® Collagen to that produced by collagen matrix in vivo.

Method:

eighteen bone defects, 5mm by 10mm were created in the parietal bone of 9 New Zealand White rabbits. 6 defects were grafted with Bio-Oss^® Collagen. 6 defects were grafted with collagen matrix alone (positive control) and 6 were left empty (negative control). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Quantitative analysis of new bone formation was made on 100 sections (50 sections for each group) using image analysis.

Results:

A total of 339% more new bone was present in defects grafted with Bio-Oss^® Collagen than those grafted with collagen matrix (positive control). No bone was formed in the negative control group.

Conclusion:

Bio-Oss^® Collagen has the effect of stimulating new bone formation locally compared with collagen matrix in vivo. Bio-Oss^® Collagen may be utilized as a bone graft material.

Orthodontie Treatment Results following Grafting Autologous Mandibular Bone to the Alveolar Cleft in Patients with a Complete Unilateral Cleft

Objective

To analyze orthodontic treatment results following mandibular symphysis bone grafting and postoperative orthodontic treatment.

Design

Randomized selection of 75 patients out of 308 with unilateral cleft of lip, alveolus, and palate, operated upon according to protocol between 1990 and 2008 in the Wilhelmina Children's Hospital, Utrecht, The Netherlands.

Main Outcome Measure

Goslon Yardstick rating changes of dental arch relationship. Significant agreement ( p < .001) was observed between the two assessments carried out with an interval of 3 months (Cohen's kappa = .963, p < .001).

Results

Following mandibular bone grafting and orthodontic treatment in 65.3% of the patients, the aim of treatment (Goslon Yardstick groups 1 and 2) had been achieved. The applied before/after Goslon allocations showed high improvement significance ( p < .001).

Conclusions

Postoperative orthodontic treatment in patients following grafting with mandibular symphysis bone showed excellent results.

Use of recombinant human Bone Morphogenetic Protein (rhBMP-2) in reconstruction of maxillary alveolar clefts

BACKGROUND

Use of rhBMP2 has been demonstrated to be an ideal bone reconstructive material for alveolar clefts. There is a lack of such studies from Indian cleft patients.

AIM

To compare rhBMP2 alveolar cleft repair and iliac crest graft treated cases.

MATERIALS AND METHOD

Retrospective analysis of rhBMP2 alveolar cleft repair and iliac crest graft treated cases.

PREDICTOR VARIABLES

Gender, type of surgery and type of cleft

OUTCOME VARIABLES

Total surgery time, blood loss at surgical and harvest site, length of scar, number of days on antibiotics, serratiopeptidase and NSAIDS; sutured days, number of days to regain masticatory functions, pain VAS on 5th postoperative day and at harvest site on a scale of 10; duration of edema, number of working days lost, time until child could walk 'normally'; mean efficiency of bone deposition.

STATISTICS

Descriptive, paired 't' test, one way ANOVA RESULTS: Difference between rhBMP2 and iliac crest graft treated cases in terms of antibiotic use, serratopeptidase, NSAIDS, pain at surgical site, edema, number of working lost for attendees and number of days to walk unaided were statistically significant. The mean length of surgery for unilateral cases was 87.60 minutes whereas it was 108.75 minutes for bilateral cases (p=0.003). The mean efficiency of bone deposition as revealed loss in radiolucency for rhBMP2 treated cases was 91.74% whereas iliac crest graft cases showed a 87.96% (p=0.006).

DISCUSSION

It is evident that one has to reject null hypothesis in favor of the alternate hypothesis. The rhBMP2 is better than the conventional gold standard of iliac crest graft for restoration of maxillary alveolar clefts in terms of considered surgical, post surgical and radiographic planimetry parameters.

CONCLUSION

Sparing children from the procedure of iliac crest harvesting is by itself a compelling reason to favor rhBMP2 use. It avoids the unnecessary surgery, loss of blood and postoperative morbidity of iliac crest harvesting.

Recent advances in presurgical molding in cleft lip and palate

PURPOSE OF REVIEW

Although many protocols for treating infants with cleft lip and palate have been successful, the severely wide deformities often require a multidisciplined team approach. Maxillary appliances have been used for 50 years; however, nasal molding is a relatively recent development that has shown progress but not without stalwart criticism.

RECENT FINDINGS

Presurgical nasal alveolar molding is an evolving technique in the treatment of cleft lip and palate. Used properly, molding can create improved nasal symmetry in unilateral cases and columellar lengthening in bilateral cases. Some regression of improvement is often seen in the following years due to differential growth patterns within the nasal subunits. The nasal septal and columellar deviation seen in unilateral cleft lip and palate can also be improved with a novel device.

SUMMARY

Although traditional repair of the cleft lip and nasal deformity is often adequate, severely wide clefts are amenable to a variety of presurgical measures. Presurgical nasal alveolar molding in children with cleft lip and palate allows repositioning of the maxillary alveolus and surrounding soft tissues in hopes of reducing wound tension and improving results. These techniques can be extremely challenging but an excellent addition to a cleft lip and palate team's armamentarium.

Effect of quercetin on bone formation

Quercetin is a flavonol, also a phytoestrogen, available commonly in onions and apples. Our laboratory compared the amount of new bone produced by quercetin in a collagen matrix to that produced by bone grafts and a collagen matrix. Eighteen bone defects, 5 x 10 mm were created in the parietal bone of nine New Zealand White rabbits. In the experimental group, six defects were grafted with quercetin solution mixed with a collagen matrix. In the control groups, six defects were grafted with a collagen matrix alone (active control) and six were left empty (passive control). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Serial sections were cut across each defect. Quantitative analysis of new bone formation was made on 100 sections (50 sections for each group) using image analysis. A total of 556% more new bone was present in defects grafted with quercetin in a collagen matrix than those grafted with a collagen matrix alone. No bone was formed in the passive control group. In conclusion, quercetin in a collagen matrix has the effect of increasing new bone formation locally, and can be used as a bone graft material.

Off-label use of recombinant human bone morphogenetic protein-2 (rhBMP-2) for reconstruction of mandibular bone defects in humans

PURPOSE

The off-label use of recombinant human bone morphogenetic protein-2 (rhBMP-2) for the treatment of mandibular bone defects was evaluated in 5 patients. The rhBMP-2 was used as an alternative to autogenous bone grafting.

PATIENTS AND METHODS

A total of 5 patients had mandibular defects reconstructed with rhBMP-2, 1.5 mg/mL, soaked collagen sponges alone or in combination with bone marrow cells and allogenic cancellous bone chips. Four of the patients had mandibular continuity defects and the fifth patient had 2 large bone cavities following removal of dentigerous cysts. Radiographs and clinical examinations were used to evaluate healing. The longest patient follow-up was 22 months after reconstruction.

RESULTS

Radiographic and clinical assessments revealed bone regeneration and restoration of the mandibular defects in 3 of the 5 patients. The rhBMP-2 failed in 2 patients with continuity defects. Both patients with failed rhBMP-2 grafts were successfully repaired using autogenous harvested from the iliac crest.

CONCLUSION

Mandibular bone defects can be successfully reconstructed using rhBMP-2 soaked sponges with and without including bone marrow cells and allogenic bone. Further studies are needed to determine the ideal combination of components that will predictably and reliably regenerate bone in different types of bone defects.

Effect of Salvia miltiorrhiza extract on bone formation

Salvia miltiorrhiza (SM) is a Chinese medicine used for treatment of cardiac diseases through improving blood circulation. Our laboratory compared the amount of new bone formed in collagen matrix with SM extract to that formed in the collagen matrix alone. Eighteen bone defects, 5 mm x 10 mm were created in the parietal bone of nine New Zealand White rabbits. In the experimental group, six defects were grafted with collagen matrix with SM extract. In the control groups, six defects were grafted with collagen matrix alone (positive control) and six were left empty (negative control). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Serial sections were cut across each defect. Quantitative analysis of new bone formation was made on 100 sections (50 sections for each group of SM and positive control) using image analysis. A total of 478% more new bone was present in defects grafted with SM extract in collagen matrix than those grafted with the collagen matrix alone. Very little new bone was formed in the passive control group. In conclusion, SM extract in collagen matrix has the effect of increasing new bone formation locally and can be used for bone grafting especially in cases with compromised vascular responses.

Reduced morbidity and improved healing with bone morphogenic protein-2 in older patients with alveolar cleft defects

BACKGROUND

In older cleft patients, alveolar bone grafting may be associated with poor wound healing, graft exposure, recurrent fistula, and failure of tooth eruption. A new procedure using a resorbable collagen matrix with bone morphogenetic protein (BMP)-2 was compared with traditional iliac crest bone graft to close alveolar defects in older patients.

METHODS

Skeletally mature patients with an alveolar cleft defect undergoing alveolar cleft repair were divided into either group 1 (BMP-2, experimental) or group 2 (traditional iliac graft, control) (n = 21). Bone healing was assessed with intraoral examination and NewTom scans (three-dimensional, Panorex, periapical films). Donor-site morbidity was determined with pain surveys. Overall cost and length of hospital stay were used to examine economic differences.

RESULTS

Preoperative and follow-up (1 year) intraoral examinations revealed fewer complications (11 percent versus 50 percent) and better estimated bone graft take in group 1 compared with group 2. Panorex and three-dimensional computed tomographic scans showed enhanced mineralization in group 1 compared with group 2. Volumetric analysis showed group 1 had a larger percentage alveolar defect filled with new bone (95 percent) compared with group 2 (63 percent). Donor-site pain intensity and frequency were significant in group 2 but not group 1. The mean length of stay was greater for group 2 compared with group 1. In addition, the mean overall cost of the procedure was greater in group 2 ($21,800) compared with group 1 ($11,100).

CONCLUSIONS

For this select group of late-presenting alveolar cleft patients, the BMP-2 procedure resulted in improved bone healing and reduced morbidity compared with traditional iliac bone grafting.

Tissue engineering solutions for cleft palates

PURPOSE

Clefts of the lip and palate are the most prevalent congenital craniofacial birth defect in humans. The developing field of tissue engineering is considered for the management of clefts of the lip and palate.

MATERIALS AND METHODS

A review of the literature was carried out by using electronic databases (such as PubMed and ISI Web of Science) to search topics including "cleft palate," "tissue engineering," "bone engineering," "palate engineering," and "alveolar bone grafting." To reflect current practice and research, these searches were limited primarily to articles published after the year 2000.

RESULTS

Current approaches for the treatment of clefts of the lip and palate include surgery and bone grafts; however, there are limitations associated with these therapies. Tissue engineering strategies, particularly alveolar bone engineering and soft tissue engineering, may provide clinicians with new alternatives. The application of these emerging technologies to a pediatric population must be well considered.

CONCLUSIONS

A tissue engineering approach may be a useful alternative for the treatment of cleft palates as it mitigates the concerns of donor site morbidity as well as provides additional options including scaffold implantation and growth factor delivery.

Effect of puerarin on bone formation

OBJECTIVE

Puerarin is one of the major phytoestrogens isolated from Pueraria lobata, a Chinese medicine known as Gegen. Our laboratory compared the amount of new bone produced by puerarin in collagen matrix (carrier) to that produced by the collagen matrix alone.

METHOD

Eighteen bone defects, 5mm by 10mm were created in the parietal bone of nine New Zealand White rabbits. In the experimental group, six defects were grafted with puerarin solution mixed with collagen matrix. In the control groups, six defects were grafted with collagen matrix alone (active control) and six were left empty (passive control). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Serial sections were cut across each defect. No new bone was formed in the passive control group. Quantitative analysis of new bone formation was made on 100 sections (10 sections in each defect, in five defects randomly selected in each of the experimental group and active control group) using image analysis.

RESULTS

A total of 554% more new bone was present in defects grafted with puerarin in collagen matrix than those grafted with the collagen matrix alone.

CONCLUSION

Puerarin in collagen matrix has the effect of increasing new bone formation locally and can be used for bone grafting or for bone induction often required in surgery.

In Vitro Manipulation of Cleft Palate Connective Tissue: Setting the Bases of a Proposed New Treatment

BACKGROUND

Palatoplasty has the undesired side effect of impaired mid-facial growth. To avoid this problem, we propose an alternative to palatoplasty. We hypothesize that if BMP-2 is injected together with a carrier into the periosteum of the cleft palate borders, border volume will increase and connective tissue cells will be activated to produce extra bone. Once these borders supported by bone reach the midline, extraction of their covering epithelia with trypsin will permit adhesion of the underlying tissues. We investigated in vitro the ability of cleft palate connective tissue cells to produce extra bone in the presence of BMP-2 and the possibility of using trypsin to remove the epithelium covering the cleft palate borders without impairing the underlying tissues' ability to adhere.

MATERIALS AND METHODS

We used the cleft palate presented by tgf-beta(3) null mice and small fragments of human cleft palate mucoperiosteum as models. Immunolabeling BMP-2-treated or untreated cultures with TUNEL and anti-osteocalcin or PCNA antibodies was performed. The epithelium of the cleft palate borders was removed with a trypsin solution, and the de-epithelialized tissues were cultured in apposition.

RESULTS

BMP-2 induces differentiation toward bone on cleft palate connective tissue cells without producing cell death or proliferation. Trypsin removal of the cleft palate margins' epithelium does not impair the underlying tissues' adhesion.

CONCLUSION

It is possible to generate extra bone at the cleft palate margins and to chemically eliminate their covering epithelia without damaging the underlying tissues, which allows further investigation in vivo of this new approach for cleft palate closure.

Status and Potential Commercial Impact of Stem Cell-Based Treatments on Dental and Craniofacial Regeneration

The projected annual demand for stem cell-based dental treatments in the United States can range from over 290 million tooth restorative treatments to 30,000 patients requiring tissue regeneration following craniofacial cancer surgery. Professional dental treatments cost Americans over $60 billion per year. Scientific advances in stem cell technologies, tissue engineering, and transplantation will provide the basis for the introduction of new treatment technologies into dentistry. This review provides an assessment of how stem cell therapies will likely change dental practice. The problems of introducing stem cell therapies are substantial, but they provide the best hope for many patients with congenital defects, and to regenerate teeth and tissues lost because of disease, cancer, and trauma, or missing because of congenital malformation. The most expensive dental treatments may be the most attractive candidates for stem cell therapies. This would indicate that craniofacial reconstruction, implants, and endodontic treatments are the most valuable applications of dental stem cell therapies, whereas tooth restorations and other dental treatments are the less commercially valuable.

Effect of naringin collagen graft on bone formation

Naringin is a flavonoid available commonly in citrus fruits and is also a HMG-CoA reductase inhibitor. Our laboratory compared the amount of new bone produced by naringin in collagen matrix to that produced by bone grafts and collagen matrix. Twenty bone defects, 5 mm x 10 mm were created in the parietal bone of 14 New Zealand White rabbits. In the experimental group, 5 defects were grafted with naringin solution mixed with collagen matrix, 5 defects were grafted with autogenous endochondral bone. In the control groups, 5 defects were grafted with collagen matrix alone (active control) and 5 were left empty (passive control). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Serial sections were cut across each defect. Quantitative analysis of new bone formation was made on 150 sections (50 sections for each group) using image analysis. A total of 284% and 490% more new bone was present in defects grafted with naringin in collagen matrix than those grafted with bone and collagen, respectively. No bone was formed in the passive control group. In conclusion, naringin in collagen matrix have the effect of increasing new bone formation locally and can be used as a bone graft material.