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Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVIII | Pages 203 - 203
1 Sep 2012
Soroceanu A Oxner W Alexander D Shakespeare D
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Purpose. Bone morphogenic protein (BMP-2) is used in spinal arthrodesis to induce bone growth. Studies have demonstrated that it achieves similar fusion rates compared to iliac crest bone graft when used in instrumented fusions. Our study aims at evaluating the requirement for instrumentation in one and two-level spinal arthrodeses when BMP-2 is used in conjunction with local bone to achieve fusion. Method. 50 patients were recruited and randomized to instrumented versus non-instrumented spinal arthrodesis. BMP-2 with local autologous bone was used in all patients. Patients are evaluated at 3-months, 6-months, 12-months, and 24-months postoperatively with questionnaires to assess clinical outcome (ODI, VAS and SF-36), and PA and lateral x-rays of the spine to assess radiographic fusion (Lenke score). At 24 months, a thin-cut (1mm) CT scan was performed. Results. Two-year data is available on 40 patients. There were no statistically significant differences between the two groups based on the clinical outcomes measured. The ODI 22.55.1 for the instrumented group vs. 13.733.57 for the non-instrumented group (p=0.2)). The VAS for the instrumented group was 2.110.61 vs. 1.530.61 for the non-instrumented group (p=0.49). The SF-36 (physical) was 62.316.71 for the instrumented group vs 54.665.43 for the study group (p=0.8). The operating time was 105.85.91 minutes for the instrumented group versus 88.63.61 minutes for the non-instrumented group (p=0.01). Blood loss was 339.139.38 cc for the instrumented group vs 273.133.8 cc for the non-instrumented group (p=0.1). Preliminary radiographic analysis showed similar fusion rates for the two groups. Two-year follow-up on all patients will be completed by February 2010. Final clinical and radiographic data analysis will be presented at the meeting. Conclusion. BMP-2 and local bone graft demonstrated functionally equivalent clinical outcomes when used with or without instrumentation in lumbar spinal fusions while offering potential reduction in operative time and blood loss


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_8 | Pages 35 - 35
1 Aug 2020
Kendal J Singla A Al-Ani A Affan A Hildebrand K Itani D Ungrin M Monument M
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Impaired bone healing biology secondary to soft tissue deficits and chemotherapy contribute to non-union, fracture and infection following limb salvage surgery in Osteosarcoma patients. Approved bone healing augments such as recombinant human bone morphogenetic protein-2 (rhBMP-2) have great potential to mitigate these complications. rhBMP-2 use in sarcoma surgery is limited, however, due to concerns of pro-oncogenic signalling within the tumour resection bed. To the contrary, recent pre-clinical studies demonstrate that BMP-2 may induce Osteosarcoma differentiation and limit tumour growth. Further pre-clinical studies evaluating the oncologic influences of BMP-2 in Osteosarcoma are needed. The purpose of this study is to evaluate how BMP-2 signalling affects Osteosarcoma cell proliferation and metastasis in an active tumour bed. Two Osteosarcoma cell lines (143b and SaOS-2) were assessed for proliferative capacity and invasion. 143b and SaOS-2 cells were engineered to upregulate BMP-2. In vitro proliferation was assessed using a cell viability assay, motility was assessed with a scratch wound healing assay, and degree of osteoblastic differentiation was assessed using qRT-PCR of Osteoblastic markers (CTGF, ALP, Runx-2 and Osx). For in vivo evaluation, Osteosarcoma cells were injected into the intramedullary proximal tibia of immunocompromised (NOD-SCID) mice and local tumour growth and metastases were assessed using weekly bioluminescence imaging (BLI) and tumour volume measurements for 4–6 weeks. At the experimental end point we assessed radiographic tumour burden using ex-vivo micro-CT, as well as tibial and pulmonary gross and histologic pathology. SaOS-2 was more differentiated than 143b, with increased expression of Runx-2 (p = 0.009), Osx (p = 0.004) and ALP (p = 0.035). BMP-2 upregulation did not stimulate an osteoblast differentiation response in 143b, but stimulated an increase in Osx expression in SaOS-2 (p = 0.002). BMP-2 upregulation in 143b cells resulted in increased proliferation in vitro (p = 0.014), faster in vitro wound healing (p = 0.03), significantly increased tumour volume (p = 0.001) with enhanced osteolysis detected on micro-CT, but did not affect rates of lung metastasis (67% vs. 71%, BMP-2 vs. Control). BMP-2 over-expression in SaOS-2 cells reduced in vitro proliferation when grown in partial osteogenic-differentiation media (p < 0.001), had no effect on in vitro wound healing (p = 0.28), reduced in vivo SaOS-2 tumour burden at 6 weeks (photon counts, p < 0.0001), decreased tumour-associated matrix deposition as assessed by trabecular thickness (p = 0.02), and did not affect rates of lung metastasis (0% vs. 0%). Our results indicate BMP-2 signalling incites a proliferative effect on a poorly differentiated Osteosarcoma cell line (143b), but conditionally reduces proliferative capacity and induces a partial differentiation response in a moderately-differentiated Osteosarcoma cell line (SaOS-2). This dichotomous effect may be due to the inherent ability for Osteosarcoma cells to undergo BMP-2 mediated terminal differentiation. Importantly, these results do not support the clinical application of BMP-2 in Osteosarcoma limb salvage surgery due to the potential for stimulating growth of poorly differentiated Osteosarcoma cells within the tumour bed. Additional studies assessing the effects of BMP-2 in an immune-competent mouse model are ongoing


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_6 | Pages 30 - 30
1 Jul 2020
Kendal J Singla A Affan A Hildebrand K Al-Ani A Itani D Ungrin M
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Impaired bone healing biology secondary to soft tissue deficits and chemotherapy contribute to non-union, fracture and infection following limb salvage surgery in Osteosarcoma patients. Approved bone healing augments such as recombinant human bone morphogenetic protein-2 (rhBMP-2) have great potential to mitigate these complications. rhBMP-2 use in sarcoma surgery is limited, however, due to concerns of pro-oncogenic signalling within the tumour resection bed. To the contrary, recent pre-clinical studies demonstrate that BMP-2 may induce Osteosarcoma differentiation and limit tumour growth. Further pre-clinical studies evaluating the oncologic influences of BMP-2 in Osteosarcoma are needed. The purpose of this study is to evaluate how BMP-2 signalling affects Osteosarcoma cell proliferation and metastasis in an active tumour bed. Two Osteosarcoma cell lines (143b and SaOS-2) were assessed for proliferative capacity and invasion. 143b and SaOS-2 cells were engineered to upregulate BMP-2. In vitro proliferation was assessed using a cell viability assay, motility was assessed with a scratch wound healing assay, and degree of osteoblastic differentiation was assessed using qRT-PCR of Osteoblastic markers (CTGF, ALP, Runx-2 and Osx). For in vivo evaluation, Osteosarcoma cells were injected into the intramedullary proximal tibia of immunocompromised (NOD-SCID) mice and local tumour growth and metastases were assessed using weekly bioluminescence imaging and tumour volume measurements for 4–6 weeks. At the experimental end point we assessed radiographic tumour burden using ex-vivo micro-CT, as well as tibial and pulmonary gross and histologic pathology. SaOS-2 was more differentiated than 143b, with significantly increased expression of the Osteoblast markers Osx (p = 0.004) and ALP (p = 0.035). BMP-2 upregulation did not stimulate an osteoblast differentiation response in 143b, but stimulated an increase in Osx expression in SaOS-2 (p = 0.002). BMP-2 upregulation in 143b cells resulted in increased proliferation in vitro (p = 0.014), faster in vitro wound healing (p = 0.03), significantly increased tumour volume (p = 0.001) with enhanced osteolysis detected on micro-CT, but did not affect rates of lung metastasis (67% vs. 71%, BMP-2 vs. Control). BMP-2 over-expression in SaOS-2 cells reduced in vitro proliferation when grown in osteogenic-differentiation media (p < 0.001), had no effect on in vitro wound healing (p = 0.28), reduced in vivo SaOS-2 tumour burden at 6 weeks (photon counts, p < 0.0001), decreased tumour-associated matrix deposition as assessed by trabecular thickness (p = 0.02), but did not affect rates of lung metastasis (0% vs. 0%). Our results indicate BMP-2 signalling incites a proliferative effect on a poorly differentiated Osteosarcoma cell line (143b), but conditionally reduces proliferative capacity and induces a partial differentiation response in a moderately-differentiated Osteosarcoma cell line (SaOS-2). This dichotomous effect may be due to the inherent ability for Osteosarcoma cells to undergo BMP-2 mediated terminal differentiation. Importantly, these results do not support the clinical application of BMP-2 in Osteosarcoma limb salvage surgery due to the potential for stimulating growth of poorly differentiated Osteosarcoma cells within the tumour bed. Additional studies assessing the effects of BMP-2 in an immune-competent mouse model are ongoing


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_4 | Pages 34 - 34
1 Jan 2016
Suh DH Shon WY
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Titanium (Ti) is well known in orthopedic implant materials such as total hip replacement arthroplasty. Osseointegration of orthopedic implants is defined as the formation of a direct interface between the implant and the bone without intervening soft tissue. Unmodified Ti is not sufficient to complete adhesion between Ti surface and host bone with subsequent implant loosening over time and ultimately implant failure. An effective approach to enhance the biological activity of orthopedic implants and improve post-implantation healing is to modify the implant surface. The aim of this study was to investigate the effect of functionalized titanium (Ti) with alendronate (Aln) and bone morphogenic protein-2 (BMP-2) for enhancement of osteoblast activity in vitro. Aln and/or BMP-2 were sequentially immobilized to the heparinized-Ti (Hep-Ti) surface. The compositions of pristine Ti and Hep-Ti with or without Aln and/or BMP-2 were characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). Osteoblast activities on all Ti substrates were investigated by cell proliferation assays, alkaline phosphate (ALP) activity, calcium deposition, gene expressions of osteocalcin and osteopontin. The modified Ti surface with heparin, Aln, BMP-2 and Aln/BMP-2 showed similar morphologies compared to that of pristine Ti on scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). Aln or BMP-2 from Aln/Hep-Ti, BMP-2/Hep-Ti or Aln/BMP-2/ Hep-Ti substrates exhibited sustained release profiles up to 4 weeks. No significant cytotoxic effects were observed for incubation periods for up to 48 h. the ALP activity of MG-63 cells cultured on Hep-Ti was not significantly different compared to those cultured on pristine Ti for 7, 14, and 21 days. Alkaline phosphatase(ALP) activities of osteoblasts cultured on Ti groups immobilized with Aln, BMP-2, or Aln/BMP-2 were significantly increased when compared to pristine Ti(p < 0.05). Calcium deposition was markedly increased in Aln/BMP-2/Hep-Ti compared to Aln/Hep-Ti or BMP-2/Hep-Ti, respectively (p < 0.05). mRNA expressions of osteocalcin(OCN) and osteopontin(OPN) of osteoblasts grown on Aln/Hep-Ti, BMP-2/Hep-Ti, and Aln/BMP-2/Hep-Ti were significantly higher than of those grown on pristine Ti (p < 0.05). Based on the results of the in vitro studies, we showed that co-delivery of alendronate and BMP-2 had an additive effect on osteoblast activity and mineralization when compared with pristine Ti as well as alendronate or BMP-2 alone. Functionalized Ti systems with alendronate and BMP-2 can give a good solution to solve the most common problems associated with orthopedic and dental implants. Furthermore, in vivo studies required to determine the optimal doses of alendronate and BMP-2 for clinical application


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 10 | Pages 1427 - 1432
1 Oct 2012
Chassanidis CG Malizos KN Varitimidis S Samara S Koromila T Kollia P Dailiana Z

Periosteum is important for bone homoeostasis through the release of bone morphogenetic proteins (BMPs) and their effect on osteoprogenitor cells. Smoking has an adverse effect on fracture healing and bone regeneration. The aim of this study was to evaluate the effect of smoking on the expression of the BMPs of human periosteum. Real-time polymerase chain reaction was performed for BMP-2,-4,-6,-7 gene expression in periosteal samples obtained from 45 fractured bones (19 smokers, 26 non-smokers) and 60 non-fractured bones (21 smokers, 39 non-smokers). A hierarchical model of BMP gene expression (BMP-2 > BMP-6 > BMP-4 > BMP-7) was demonstrated in all samples. When smokers and non-smokers were compared, a remarkable reduction in the gene expression of BMP-2, -4 and -6 was noticed in smokers. The comparison of fracture and non-fracture groups demonstrated a higher gene expression of BMP-2, -4 and -7 in the non-fracture samples. Within the subgroups (fracture and non-fracture), BMP gene expression in smokers was either lower but without statistical significance in the majority of BMPs, or similar to that in non-smokers with regard to BMP-4 in fracture and BMP-7 in non-fracture samples. In smokers, BMP gene expression of human periosteum was reduced, demonstrating the effect of smoking at the molecular level by reduction of mRNA transcription of periosteal BMPs. Among the BMPs studied, BMP-2 gene expression was significantly higher, highlighting its role in bone homoeostasis


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_15 | Pages 5 - 5
1 Dec 2021
Alagboso F Mannala G Steinmann S Docheva D Rupp M Brochhausen C Alt V
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Aim. Bone regeneration following the treatment of Staphylococcal bone infection or osteomyelitis is challenging due to the ability of Staphylococcus aureus to invade and persist within bone cells, which could possibly lead to antimicrobial tolerance and incessant bone destruction. Here, we investigated the influence of Staphylococcal bone infection on osteoblasts metabolism and function, with the underlying goal of determining whether Staphylococcus aureus-infected osteoblasts retain their ability to produce extracellular mineralized organic matrix after antibiotic treatment. Method. Using our in vitro infection model, human osteoblasts-like Saos-2 cells were infected with high-grade Staphylococcus aureus EDCC 5055 strain, and then treated with 8 µg/ml rifampicin and osteogenic stimulators up to 21-days. Results. Immunofluorescence and transmission electron microscopic (TEM) imaging demonstrated the presence of intracellular bacteria within the infected osteoblasts as early as 2 hours post-infection. TEM micrographs revealed intact intracellular bacteria with dividing septa indicative of active replication. The infected osteoblasts showed significant amounts of intracellular bacteria colonies and alteration in metabolic activity compared to the uninfected osteoblasts (p≤0.001). Treatment of S. aureus-infected osteoblasts with a single dose of 8 µg/ml rifampicin sufficiently restored the metabolic activity comparative to the uninfected groups. Alizarin red staining and quantification of the rifampicin-treated infected osteoblasts revealed significantly lower amount of mineralized extracellular matrix after 7-days osteogenesis (p<0.05). Interestingly, prolonged osteogenic stimulation and rifampicin-treatment up to 21 days improved the extracellular matrix mineralization level comparable to the rifampicin-treated uninfected group. However, the untreated (native) osteoblasts showed significantly more quantity of mineral deposits (p≤0.001). Ultrastructural analysis of the rifampicin-treated infected osteoblasts at 21-days osteogenesis revealed active osteoblasts and newly differentiated osteocytes, with densely distributed calcium crystal deposits within the extracellular organic matrix. Moreover, residual colony of dead bacteria bodies and empty vacuoles of the fully degraded bacteria embedded within the mineralized extracellular matrix. Gene expression level of prominent bone formation markers, namely RUNX2, COL1A1, ALPL, BMP-2, SPARC, BGLAP, OPG/RANKL showed no significant difference between the infected and uninfected osteoblast at 21-days of osteogenesis. Conclusions. Staphylococcus aureus bone infection can drastically impair osteoblasts metabolism and function. However, treatment with potent intracellular penetrating antibiotics, namely rifampicin restored the metabolic and bone formation activity of surviving osteoblasts. Delay in early osteogenesis caused by the bacterial infection was significantly improved over time after successful intracellular bacteria eradication


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIX | Pages 49 - 49
1 Sep 2012
Brown K Li B Guda T Perrien D Guelcher S Wenke J
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Infection is a common complication of severe open fractures and compromises bone healing. The present standard of care is a two-stage approach comprising of initial placement of antibiotic-impregnated PMMA beads to control infection followed later by bone grafting. Although the systemic antibiotics and PMMA/antibiotic beads control the infection initially, there are often residual bacteria within the wound. After grafting and definitive closure, the implanted graft is placed in an avascular defect and could function as a nidus for infection. Bioactive porous polyurethane (PUR) scaffolds have been shown to improve bone healing by delivering recombinant human bone morphogenetic protein-2 (BMP-2) and reduce infection by delivering antibiotics. The release kinetics of the BMP-2 were an initial burst to recruit cells and sustained release to induce the migrating cells. The Vancomycin (Vanc) release kinetics were designed to protect the graft from contamination until vascularisation by having an initial burst and then remaining over the MIC for Staph. aueus for two months. In this study, PUR+BMP-2+Vanc scaffolds were first tested in a non-infected critical size rat femoral segmental defect and was found to perform comparably to PUR+BMP-2, thus indicating that Vanc did not hinder bone healing. PUR+BMP-2+Vanc scaffolds were subsequently evaluated in an infected critical size rat femoral segmental defect. The dual delivery approach resulted in significantly more new bone formation and infection control than both PUR+BMP-2 and the collagen+BMP-2 treatments. These data indicate that the dual-delivery strategy effectively protects the graft from infection during wound healing and regenerates more bone in contaminated defects. This moderately osteoconductive bone graft is capable of being injected, provides a more sustained release of BMP-2 than the collagen sponge, and can release antibiotics for over 8 weeks. The dual-delivery approach may improve patient outcomes of open fractures by protecting the osteoinductive graft from colonization until vascularization occurs


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXI | Pages 184 - 184
1 May 2012
G. NS P. W D. M K. JM
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Background. Current treatments for the prevention of thromboembolism include heparin and low-molecular weight heparins (LMWHs). A number of studies have suggested that long term administration of these drugs may adversely affect osteoblasts and therefore, bone metabolism. Xarelto(tm) (Rivaroxaban) is a new anti-thrombotic drug for the prevention of venous thromboembolism in adult patients undergoing elective hip and knee replacement surgery. The aim of this in vitro study was to investigate the possible effects of rivaroxaban on osteoblast proliferation, function, matrix mineralisation and gene expression compared to enoxaparin, a commonly used LMWH. Methods. Primary human osteoblast cultures were treated with varying concentrations of rivaroxaban (0.013, 0.13, 1.3 and 13 μg/ml) or enoxaparin (0.1, 1.0 and 10 international units/ml). The effect of each drug on osteoblast function and matrix mineralisation was evaluated by measuring alkaline phosphatase activity and calcium deposition, respectively. The MTS assay was used to assess the effect of drug treatments on cell proliferation. Changes in osteocalcin, Runx2 and BMP-2 messenger RNA (mRNA) expression following drug treatments were measured by real-time polymerase chain reaction (PCR). Results. Rivaroxaban and enoxaparin treatment did not adversely affect osteoblast proliferation. However, both drugs caused a significant reduction in osteoblast function, as measured by alkaline phosphatase activity, with a moderate reduction in calcium deposition also observed. This reduction in osteoblast function was associated with a reduction in the mRNA expression of the bone marker, osteocalcin, the transcription factor, Runx2, and the osteogenic factor, BMP-2. Conclusion. These data show that rivaroxaban treatment may negatively affect bone through a reduction in osteoblast function. The increased duration of recommended Rivaroxaban therapy (2 and 5 weeks) post-arthroplasty compared to Enoxaparin therapy (average one week) may have a more pronounced effect on bone homeostasis


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_IV | Pages 71 - 71
1 Mar 2012
Giannoudis P Pountos I Morley J Perry S Pape H
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Purpose. The aim of this study was to investigate whether growth factors essential for fracture healing are released in the immediate aftermath following fracture and whether reaming of IM cavity causes increased liberation of these autocoids. Methods. Consecutive adult patients with femoral shaft fractures forming two groups (a group who received unreamed nail (n=10) and a second group who received reamed nail (n=10) were recruited for this study. Peripheral blood samples and samples from the femoral canal before and after reaming and before and after the solid nail insertion were collected. Serum was extracted and using Elisa colorimetric assays the concentration of Platelet Derived Growth Factor (PDGF), Vascular Endothelial Growth Factor (VEGF), Insulin-like Growth Factor I (IGF-I) Transforming Growth Factor beta 1 (TGF-. 2. 1) and BMP-2 levels was measured. Results. In total 20 patients were studied. The mean age was 38 years (range 20-63). Reaming substantially increased all studied growth factors locally in the femoral canal. VEGF and PDGF were increased after reaming by 111.2% and 115.6% respectively. IGF-1 was increased by 31.5% and TGF-b1 was increased by 54.2%. In the unreamed group the levels of PDGF-BB, VEGF and TGF-. 2. 1 were not changed while the levels of IGF-I were decreased by 10%. The levels of these factors in peripheral circulation were not altered despite the technique used. BMP-2 levels during all time points were below the detection limit of the immunoassay. Conclusion and significance. This study indicates that reaming of IM Canal is associated with increased liberation of growth factors. The osteogenic effect of reaming could be secondary not only to grafting debris but also to the increased liberation of these molecules


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIII | Pages 131 - 131
1 May 2012
Liu R Peacock L Mikulec K Morse A Schindeler A Little D
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Bone morphogenetic proteins (BMPs) are able to induce osteogenic differentiation in many cells, including muscle cells. However, the actual contribution of muscle cells to bone formation and repair is unclear. Our objective was to examine the capacity of myogenic cells to contribute to BMP-induced ectopic bone formation and fracture repair. Osteogenic gene expression was measured by quantitative PCR in osteoprogenitors, myoblasts, and fibroblasts following BMP-2 treatment. The MyoD-Cre x ROSA26R and MyoD-Cre x Z/AP mouse strains were used to track the fate of MyoD+ cells in vivo. In these double-transgenic mice, MyoD+ progenitors undergo a permanent recombination event to induce reporter gene expression. Ectopic bone was produced by the intramuscular implantation of BMP-7. Closed tibial fractures and open tibial fractures with periosteal stripping were also performed. Cellular contribution was tracked at one, two and three week time points by histological staining. Osteoprogenitors and myoblasts exhibited comparable expression of early and late bone markers; in contrast bone marker expression was considerably less in fibroblasts. The sensitivity of cells to BMP-2 correlated with the expression of BMP receptor-1a (Bmpr1a). Pilot experiments using the MyoD-Cre x Rosa26R mice identified a contribution by MyoD expressing cells in BMP-induced ectopic bone formation. However, false positive LacZ staining in osteoclasts led us to seek alternative systems such as the MyoD-cre x Z/AP mice that have negligible background staining. Initially, a minor contribution from MyoD expressing cells was noted in the ectopic bones in the MyoD-cre x Z/AP mice, but without false positive osteoclast staining. Soft tissue trauma usually precedes the formation of ectopic bone. Hence, to mimic the clinical condition more precisely, physical injury to the muscle was performed. Traumatising the muscle two days prior to BMP-7 implantation: (1) induced MyoD expression in quiescent satellite cells; (2) increased ectopic bone formation; and (3) greatly enhanced the number of MyoD positive cells in the ectopic bone. In open tibial fractures the majority of the initial callus was MyoD+ indicating a significant contribution by myogenic cells. In contrast, closed fractures with the periosteum intact had a negligible myogenic contribution. Myoblasts but not fibroblasts were highly responsive to BMP stimulation and this was associated with BMP receptor expression. Our transgenic mouse models demonstrate for the first time that muscle progenitors can significantly contribute to ectopic bone formation and fracture repair. This may have translational applications for clinical orthopaedic therapies


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 91 - 91
1 May 2016
Nurkovic J Ramovic A Nurkovic S Kurtagic I Dolicanin Z
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Bone is capable of regeneration, and defects often heal spontaneously. However, cartilage, tendon, and ligament injuries usually result in replacement if the site by organized scar tissue, which is inferior to the native tissue. The osteogenic potential of mesenchymal stem cells (MSCs) has already been verified. MSCs hold great potential for the development of new treatment strategies for a host of orthopedic conditions. The multi-lineage potential and plasticity of MSCs allow them to be building blocks for a host of nonhematopoietic tissues, including bone. More recently, several groups have reported on the successful clinical application of tissue engineering strategies in the repair of bony defects in patients secondary to trauma and tumor resection. Advances in fabrication of biodegradable scaffolds that serve as beds for MSC implantation will hopefully lead to better biocompatibility and host tissue integration. Current strategies for bone tissue engineering include the use of osteoconductive matrix devices that promote bony ingrowth, and the delivery of osteoinductive growth factors, including bone morphogenetic protein (BMP) family, BMP-2 and BMP-7, to bony defect sites. Minimal toxicity has been observed in animal models involving genetically-manipulated stem cells transduced with retroviral and adenoviral vectors. Gene therapy using stem cells as delivery vehicles is a powerful weapon that can be used in a plethora of clinical situations that would benefit from the osteoinductive, proliferative, and angiogenic effects of growth factors. With better understanding of the biology of stem cells in the future and with enhancement of technologies that are capable to influence, modify, and culture these cells, a new field of regenerative skeletal medicine may emerge


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_15 | Pages 92 - 92
1 Aug 2017
Paprosky W
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Bone is a dynamic organ with remarkable regenerative properties seen only otherwise in the liver. However, bone healing requires vascularity, stability, growth factors, a matrix for growth, and viable cells to obtain effective osteosynthesis. We rely on these principles not only to heal fractures, but also achieve healing of benign bone defects. Unfortunately we are regularly confronted with situations where the local environment and tissue is insufficient and we must rely on our “biologic tool box.” When the process of bone repair requires additional assistance, we often look to bone grafting to provide an osteoconductive, osteoinductive, and/or osteogenic environment to promote bone healing and repair. The primary workhorses of bone grafting include autogenous bone, cadaver allograft, and bone graft substitutes. Among the first types of bone graft used and still used in large quantities today include autogenous and cadaver allograft bone. Allografts are useful because it is present in multiple forms that conform to the desired situation. But autogenous bone graft is considered the gold standard because it possesses all the fundamental properties to heal bone. However, it has been associated with high rates of donor site morbidity and typically requires an inpatient hospitalization following the procedure only adding to the associated costs. The first bone graft substitute use was calcium sulfate in 1892, and over the past 122 years advancements have achieved improved material properties of calcium sulfate and helped usher in additional bioceramics for bone grafting. Today there are predominantly four types of bioceramics available, which include calcium sulfate, calcium phosphate, tricalcium phosphate, and coralline hydroxyapatite. They come in multiple forms ranging from pellets and solid blocks to injectable and moldable putty. In comparison to autogenous bone graft, the primary limitation of bioceramics are the lack of osteogenic and osteoinductive properties. Bioceramics work by creating an osteoconductive scaffold to promote osteosynthesis. The options of bone graft substitutes don't end with these four types of bioceramics. Composite bioceramics take advantage of the differing biomechanical properties of these four basis types of bioceramics to develop improved materials. To overcome the lack of osteoinductive and osteogenic properties growth factors or bone marrow aspirate can be added to the bioceramic. As a result, the list of combinations available in our “biologic tool box” continues to expand. More than 20 BMPs have been identified, but only BMP-2 and BMP-7 have FDA approval. As we look forward to areas of future research and need within orthobiologics, some will likely come in the near future while others are much further in the future. We will continue to strive for the ideal bone graft substitute, which will have similar osteoinductive properties as autograft. The ultimate bone graft substitute will likely involve stem cells because it will allow an alternative to autogenous bone with the same osteogenic potential


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_7 | Pages 55 - 55
1 Apr 2017
Jacobs J
Full Access

Bone is a dynamic organ with remarkable regenerative properties seen only otherwise in the liver. However, bone healing requires vascularity, stability, growth factors, a matrix for growth, and viable cells to obtain effective osteosynthesis. We rely on these principles not only to heal fractures, but also achieve healing of benign bone defects. Unfortunately, we are regularly confronted with situations where the local environment and tissue is insufficient and we must rely on our “biologic tool box.” When the process of bone repair requires additional assistance, we often look to bone grafting to provide an osteoconductive, osteoinductive, and/or osteogenic environment to promote bone healing and repair. The primary workhorses of bone grafting includes autogenous bone, cadaver allograft, and bone graft substitutes. Among the first types of bone graft used and still used in large quantities today include autogenous and cadaver allograft bone. Allografts are useful because it is present in multiple forms that conform to the desired situation. But autogenous bone graft is considered the gold standard because it possesses all the fundamental properties to heal bone. However, it has been associated with high rates of donor site morbidity and typically requires an inpatient hospitalization following the procedure only adding to the associated costs. The first bone graft substitute use was calcium sulfate in 1892, and over the past 122 years advancements have achieved improved material properties of calcium sulfate and helped usher in additional bioceramics for bone grafting. Today there are predominantly 4 types of bioceramics available, which include calcium sulfate, calcium phosphate, tricalcium phosphate, and coralline hydroxyapatite. They come in multiple forms ranging from pellets and solid blocks to injectable and moldable putty. In comparison to autogenous bone graft, the primary limitation of bioceramics are the lack of osteogenic and osteoinductive properties. Bioceramics work by creating an osteoconductive scaffold to promote osteosynthesis. The options of bone graft substitutes don't end with these four types of bioceramics. Composite bioceramics take advantage of the differing biomechanical properties of these four basis types of bioceramics to develop improved materials. To overcome the lack of osteoinductive and osteogenic properties growth factors or bone marrow aspirate can be added to the bioceramic. As a result, the list of combinations available in our “biologic tool box” continues to expand. More than 20 BMPs have been identified, but only BMP-2 and BMP-7 have FDA approval. As we look forward to areas of future research and need within orthobiologics, some will likely come in the near future while others are much further in the future. We will continue to strive for the ideal bone graft substitute, which will have similar osteoinductive properties as autograft. The ultimate bone graft substitute will likely involve stem cells because it will allow an alternative to autogenous bone with the same osteogenic potential


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_22 | Pages 57 - 57
1 Dec 2016
Jacobs J
Full Access

Bone is a dynamic organ with remarkable regenerative properties seen only otherwise in the liver. However, bone healing requires vascularity, stability, growth factors, a matrix for growth, and viable cells to obtain effective osteosynthesis. We rely on these principles not only to heal fractures, but also achieve healing of benign bone defects. Unfortunately we are regularly confronted with situations where the local environment and tissue is insufficient and we must rely on our “biologic tool box.” When the process of bone repair requires additional assistance, we often look to bone grafting to provide an osteoconductive, osteoinductive, and/or osteogenic environment to promote bone healing and repair. The primary workhorses of bone grafting include autogenous bone, cadaver allograft, and bone graft substitutes. Among the first types of bone graft used and still used in large quantities today include autogenous and cadaver allograft bone. Allografts are useful because it is present in multiple forms that conform to the desired situation. But autogenous bone graft is considered the gold standard because it possesses all the fundamental properties to heal bone. However, it has been associated with high rates of donor site morbidity and typically requires an inpatient hospitalization following the procedure only adding to the associated costs. The first bone graft substitute use was calcium sulfate in 1892, and over the past 122 years advancements have achieved improved material properties of calcium sulfate and helped usher in additional bioceramics for bone grafting. Today there are predominantly 4 types of bioceramics available, which include calcium sulfate, calcium phosphate, tricalcium phosphate, and coralline hydroxyapatite. They come in multiple forms ranging from pellets and solid blocks to injectable and moldable putty. In comparison to autogenous bone graft, the primary limitation of bioceramics are the lack of osteogenic and osteoinductive properties. Bioceramics work by creating an osteoconductive scaffold to promote osteosynthesis. The options of bone graft substitutes don't end with these four types of bioceramics. Composite bioceramics take advantage of the differing biomechanical properties of these four basis types of bioceramics to develop improved materials. To overcome the lack of osteoinductive and osteogenic properties growth factors or bone marrow aspirate can be added to the bioceramic. As a result, the list of combinations available in our “biologic tool box” continues to expand. More than 20 BMPs have been identified, but only BMP-2 and BMP-7 have FDA approval. As we look forward to areas of future research and need within orthobiologics, some will likely come in the near future while others are much further in the future. We will continue to strive for the ideal bone graft substitute, which will have similar osteoinductive properties as autograft. The ultimate bone graft substitute will likely involve stem cells because it will allow an alternative to autogenous bone with the same osteogenic potential


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_17 | Pages 93 - 93
1 Nov 2016
Rosenberg A
Full Access

Bone is a dynamic organ with remarkable regenerative properties seen only otherwise in the liver. However, bone healing requires vascularity, stability, growth factors, a matrix for growth, and viable cells to obtain effective osteosynthesis. We rely on these principles not only to heal fractures, but also achieve healing of benign bone defects. Unfortunately, we are regularly confronted with situations where the local environment and tissue is insufficient and we must rely on our “biologic tool box.” When the process of bone repair requires additional assistance, we often look to bone grafting to provide an osteoconductive, osteoinductive, and/or osteogenic environment to promote bone healing and repair. The primary workhorses of bone grafting include autogenous bone, cadaver allograft, and bone graft substitutes. Among the first types of bone graft used and still used in large quantities today include autogenous and cadaver allograft bone. Allografts are useful because they are present in multiple forms that conform to the desired situation. But autogenous bone graft is considered the gold standard because it possesses all the fundamental properties to heal bone. However, it has been associated with high rates of donor site morbidity and typically requires an inpatient hospitalization following the procedure only adding to the associated costs. The first bone graft substitute used was calcium sulfate in 1892, and over the past 122 years advancements have achieved improved material properties of calcium sulfate and helped usher in additional bioceramics for bone grafting. Today there are predominantly four types of bioceramics available, which include calcium sulfate, calcium phosphate, tricalcium phosphate, and coralline hydroxyapatite. They come in multiple forms ranging from pellets and solid blocks to injectable and moldable putty. In comparison to autogenous bone graft, the primary limitation of bioceramics are the lack of osteogenic and osteoinductive properties. Bioceramics work by creating an osteoconductive scaffold to promote osteosynthesis. The options of bone graft substitutes don't end with these four types of bioceramics. Composite bioceramics take advantage of the differing biomechanical properties of these four basis types of bioceramics to develop improved materials. To overcome the lack of osteoinductive and osteogenic properties growth factors or bone marrow aspirate can be added to the bioceramic. As a result, the list of combinations available in our “biologic tool box” continues to expand. More than 20 BMPs have been identified, but only BMP-2 and BMP-7 have FDA approval. As we look forward to areas of future research and need within orthobiologics, some will likely come in the near future while others are much further in the future. We will continue to strive for the ideal bone graft substitute, which will have similar osteoinductive properties as autograft. The ultimate bone graft substitute will likely involve stem cells because it will allow an alternative to autogenous bone with the same osteogenic potential


Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_1 | Pages 59 - 59
1 Feb 2015
Jacobs J
Full Access

Bone is a dynamic organ with remarkable regenerative properties seen only otherwise in the liver. However, bone healing requires vascularity, stability, growth factors, a matrix for growth, and viable cells to obtain effective osteosynthesis. We rely on these principles not only to heal fractures, but also achieve healing of benign bone defects. Unfortunately we are regularly confronted with situations where the local environment and tissue is insufficient and we must rely on our “biologic tool box.” When the process of bone repair requires additional assistance, we often look to bone grafting to provide an osteoconductive, osteoinductive, and/or osteogenic environment to promote bone healing and repair. The primary workhorses of bone grafting includes autogenous bone, cadaver allograft, and bone graft substitutes. Among the first types of bone graft used and still used in large quantities today include autogenous and cadaver allograft bone. Allografts are useful because it is present in multiple forms that conform to the desired situation. But autogenous bone graft is considered the gold standard because it possesses all the fundamental properties to heal bone. However, it has been associated with high rates of donor site morbidity and typically requires an inpatient hospitalization following the procedure only adding to the associated costs. The first bone graft substitute use was calcium sulfate in 1892, and over the past 122 years advancements have achieved improved material properties of calcium sulfate and helped usher in additional bioceramics for bone grafting. Today there are predominantly 4 types of bioceramics available, which include calcium sulfate, calcium phosphate, tricalcium phosphate, and coralline hydroxyapatite. They come in multiple forms ranging from pellets and solid blocks to injectable and moldable putty. In comparison to autogenous bone graft, the primary limitation of bioceramics are the lack of osteogenic and osteoinductive properties. Bioceramics work by creating an osteoconductive scaffold to promote osteosynthesis. The options of bone graft substitutes don't end with these four types of bioceramics. Composite bioceramics take advantage of the differing biomechanical properties of these four basis types of bioceramics to develop improved materials. To overcome the lack of osteoinductive and osteogenic properties growth factors or bone marrow aspirate can be added to the bioceramic. As a result, the list of combinations available in our “biologic tool box” continues to expand. More than 20 BMPs have been identified, but only BMP-2 and BMP-7 have FDA approval. As we look forward to areas of future research and need within orthobiologics, some will likely come in the near future while others are much further in the future. We will continue to strive for the ideal bone graft substitute, which will have similar osteoinductive properties as autograft. The ultimate bone graft substitute will likely involve stem cells because it will allow an alternative to autogenous bone with the same osteogenic potential


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVIII | Pages 4 - 4
1 Sep 2012
Chen C Uludag H Wang Z Jiang H
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Purpose. The data regarding the effects of noggin on bone morphogenetic protein (BMP)-induced osteogenesis of mesenchymal stem cells (MSCs) are controversial. Most studies performed in rodent cells/models indicated that noggin was a negative regulator of BMP-2-induced osteogenesis; however, one study conducted with human MSCs in culture showed that the addition of noggin induced osteogenesis in vitro. To clear the controversy, we designed this study to evaluate the effects of knocking down noggin gene expression on BMP-2-induced osteogenesis of human bone marrow-derived primary MSCs in vitro. Method. MSCs were isolated from human tibial bone marrow by density gradient centrifugation. Two noggin small interfering RNAs (siRNAs) were used in this study to knockdown noggin gene expression. There were four study groups: MSCs with no transfection of siRNA (named as NT group), MSCs transfected with non-targeting negative control siRNA (named as control group), MSCs transfected with noggin siRNA1 (named as NOGsi1 group), and MSCs transfected with noggin siRNA2 (named as NOGsi2 group). After transfection, MSCs were induced to undergo osteogenic differentiation by incubating in basal medium containing 0.1 μg/ml BMP-2 for 35 days. The expression levels of osteoblastic marker genes were measured by real-time quantitative PCR on day 14. Also assessed was alkaline phosphatase (ALP) activity by a colorimetric kinetic assay and Fast Blue B staining on day 14. Calcium deposition was determined by the calcium assay on day 35. Results. The expression levels of integrin binding sialoprotein (IBSP) and osteocalcin (OC) were significantly decreased in both NOGsi1 and NOGsi2 groups compared with NT and control groups (all p<0.038). Although the expression level of runt-related transcription factor 2 (RUNX2) was also reduced in NOGsi1 and NOGsi2 groups compared with NT and control groups, it did not reach statistical significance. ALP activity was significantly lower in NOGsi1 and NOGsi2 groups than that of NT group (both p<0.024). The same pattern was also observed in ALP Fast Blue B staining. Calcium deposition was also significantly decreased in both NOGsi1 and NOGsi2 groups compared with NT group (both p<=0.048). Conclusion. Noggin suppression by siRNA inhibits BMP-2-induced osteogenesis of human bone marrow-derived MSCs. Our results, contrary to the extensive studies conducted in rodent cells/models, corroborated with the previous study that the addition of noggin in the cell culture increased osteogenesis of human MSCs. This suggests that the effects of noggin on BMP-2-induced osteogenesis of MSCs might be species-specific


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XLI | Pages 8 - 8
1 Sep 2012
Lovric V Ledger M Goldberg J Harper W Yu Y Walsh W
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Animal studies examining tendon-bone healing have demonstrated that the overall structure, composition, and organization of direct type entheses are not regenerated following repair. We examined the effect of Low-Intensity Pulsed Ultrasound (LIPUS) on tendon-bone healing. LIPUS may accelerate and augment the tendon-bone healing process through alteration of critical molecular expressions. Eight skeletally mature wethers, randomly allocated to either control group (n=4) or LIPUS group (n=4), underwent rotator cuff surgery following injury to the infraspinatus tendon. All animals were sacrificed 28 days post surgery to allow examination of early effects of LIPUS. Humeral head – infraspinatus tendon constructs were harvested and processed for histology and immunohistochemical staining for BMP2, Smad4, VEGF and RUNX2. All the growth factors were semiquantitative evaluated. T-tests were used to examine differences which were considered significant at p < 0.05. Levene's Test (p < 0.05) was used to confirm variance homogeneity of the populations. The surgery and LIPUS treatment were well tolerated by all animals. Placement of LIPUS sensor did not unsettle the animals. Histologic appearance at the tendon-bone interface in LIPUS treated group demonstrated general improvement in appearance compared to controls. Generally a thicker region of newly formed woven bone, morphologically resembling trabecular bone, was noted at the tendon-bone interface in the LIPUS-treated group compared to the controls. Structurally, treatment group also showed evidence of a mature interface between tendon and bone as indicated by alignment of collagen fibres as visualized under polarized light. Immunohistochemistry revealed an increase in the protein expression patterns of VEGF (p = 0.038), RUNX2 (p = 0.02) and Smad4 (p = 0.05) in the treatment group. There was no statistical difference found in the expression patterns of BMP2. VEGF was positively stained within osteoblasts in newly formed bone, endothelial cells and some fibroblasts at the interface and focally within fibroblasts around the newly formed vessels. Expression patterns of RUNX2 were similar to that of BMP-2; the staining was noted in active fibroblasts found at the interface as well as in osteoblast-like cells and osteoprogenitor cells. Immunostaining of Smad4 was present in all cell types at the healing interface. The results of this study indicate that LIPUS may aid in tendon to bone healing process in patients who have undergone rotator cuff repair. This treatment may also be beneficial following other types of reconstructive surgeries involving the tendon-bone interface


The Bone & Joint Journal
Vol. 97-B, Issue 4 | Pages 572 - 576
1 Apr 2015
Polfer EM Hope DN Elster EA Qureshi AT Davis TA Golden D Potter BK Forsberg JA

Currently, there is no animal model in which to evaluate the underlying physiological processes leading to the heterotopic ossification (HO) which forms in most combat-related and blast wounds. We sought to reproduce the ossification that forms under these circumstances in a rat by emulating patterns of injury seen in patients with severe injuries resulting from blasts. We investigated whether exposure to blast overpressure increased the prevalence of HO after transfemoral amputation performed within the zone of injury. We exposed rats to a blast overpressure alone (BOP-CTL), crush injury and femoral fracture followed by amputation through the zone of injury (AMP-CTL) or a combination of these (BOP-AMP). The presence of HO was evaluated using radiographs, micro-CT and histology. HO developed in none of nine BOP-CTL, six of nine AMP-CTL, and in all 20 BOP-AMP rats. Exposure to blast overpressure increased the prevalence of HO.

This model may thus be used to elucidate cellular and molecular pathways of HO, the effect of varying intensities of blast overpressure, and to evaluate new means of prophylaxis and treatment of heterotopic ossification.

Cite this article: Bone Joint J 2015;97-B:572–6


Bone & Joint Research
Vol. 3, Issue 6 | Pages 193 - 202
1 Jun 2014
Hast MW Zuskov A Soslowsky LJ

Tendinopathy is a debilitating musculoskeletal condition which can cause significant pain and lead to complete rupture of the tendon, which often requires surgical repair. Due in part to the large spectrum of tendon pathologies, these disorders continue to be a clinical challenge. Animal models are often used in this field of research as they offer an attractive framework to examine the cascade of processes that occur throughout both tendon pathology and repair. This review discusses the structural, mechanical, and biological changes that occur throughout tendon pathology in animal models, as well as strategies for the improvement of tendon healing.

Cite this article: Bone Joint Res 2014;3:193–202.