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PubMed1993

Granular hydroxyapatite and allogeneic demineralized bone matrix in rabbit skull defect augmentation.

To study the effect of hydroxyapatite (HA) granules on new bone formation induced by allogeneic demineralized bone matrix (DBM) and to ascertain the specific dose response of bone regeneration in rabbit calvarial defects, implantation with different doses of DBM, HA granules and a mixture of DBM with HA, respectively, was undertaken. The results showed that the largest quantity of cartilage in the fourth week and woven and remodeled bone covering almost the whole area of the defect in the tenth and twelfth week, was visible in the 20-30 mg but not in the 40 mg DBM groups. New bone formation in the defects implanted with DBM and HA was markedly less than in those implanted with DBM alone and a large amount of fibrous tissue was initiated by HA granules. A significant negative correlation between new bone formation and fibrous tissue ingrowth was noted. HA granules, as disturbing the bone regeneration induced by DBM, are thus not a desirable combination, and a dose-block phenomenon according to the amount of DBM must be anticipated in repairing skull defects.

Animals↗
PubMed2006

Intervariability and intravariability of bone morphogenetic proteins in commercially available demineralized bone matrix products.

STUDY DESIGN: Enzyme-linked immunosorbent assay was used to detect bone morphogenetic proteins (BMPs) 2, 4, and 7 in 9 commercially available ("off the shelf") demineralized bone matrix (DBM) product formulations using 3 different manufacturer's production lots of each DBM formulation. OBJECTIVES: To evaluate and compare the quantity of BMPs among several different DBM formulations (inter-product variability), as well as examine the variability of these proteins in different production lots within the same DBM formulation (intra-product variability). SUMMARY OF BACKGROUND DATA: DBMs are commonly used to augment available bone graft in spinal fusion procedures. Surgeons are presented with an ever-increasing variety of commercially available human DBMs from which to choose. Yet, there is limited information on a specific DBM product's osteoinductive efficacy, potency, and constancy. METHODS: There were protein extracts from each DBM sample separately dialyzed 4 times against distilled water at 4 degrees C for 48 hours. The amount of BMP-2, BMP-4, and BMP-7 was determined using enzyme-linked immunosorbent assay. RESULTS.: The concentrations of detected BMP-2 and BMP-7 were low for all DBM formulations, only nanograms of BMP were extracted from each gram of DBM (20.2-120.6 ng BMP-2/g DBM product; 54.2-226.8 ng BMP-7/g DBM). The variability of BMP concentrations among different lots of the same DBM formulation, intra-product variability, was higher than the variability of concentrations among different DBM formulations, inter-product variability (coefficient of variation range BMP-2 [16.34% to 76.01%], P < 0.01; BMP-7 [3.71% to 82.08%], P < 0.001). BMP-4 was undetectable. CONCLUSIONS: The relative quantities of BMPs in DBMs are low, in the order of 1 x 10(-9) g of BMP/g of DBM. There is higher variability in concentration of BMPs among 3 different lots of the same DBM formulation than among different DBM formulations. This variability questions DBM products' reliability and, possibly, efficacy in providing consistent osteoinduction.

Biological Products↗
PubMed2002

Preparation and degradation characteristic study of bone repair composite of DL-polylactic acid/hydroxyapatite/decalcifying bone matrix.

OBJECTIVE: To explore the preparative method and study the degradation characteristics of bone repair composite of DL-polylactic acid (PDLLA)/hydroxyapatite(HA)/decalcifying bone matrix (DBM) in vitro. METHODS: An emulsion blend method was developed to prepare the composite of PDLLA/HA/DBM in weight ratio of PDLLA:HA:DBM = 1.5-2:1-1.5:1. The dynamic changes of weight, biomechanical property and pH value of PDLLA/HA/DBM and PDLLA in phosphate buffered saline (PBS, pH 7.4) were studied respectively through degradation tests in vitro. RESULTS: Without being heated, PDLLA, HA and DBM could be synthesized with the emulsion blend method as bone composite of PDLLA/HA/DBM, which had both osteoconductive and osteoinductive effects. The diameter of the aperture was 100-400 microm and the gap rate was 71.3%. During degradation, the pH value of PDLLA solution decreased lightly within 2 weeks, but decreased obviously at the end of 4 weeks and the value was 4.0. While the pH value of PDLLA/HA/DBM kept quite steady and was 6.4 at the end of 12 weeks. The weight of PDLLA changed little within 4 weeks, then changed obviously and was 50% of its initial weight at the end of 12 weeks. While the weight of PDLLA/HA/DBM changed little within 5 weeks, then changed obviously and was 60% of the initial weight at the end of 12 weeks. The initial biomechanical strength of PDLLA was 1.33 MPa, decreased little within 3 weeks, then changed obviously and kept at 0.11 MPa at the end of 12 weeks. The initial biomechanical strength of PDLLA/HA/DBM was 1.7 MPa, decreased little within 4 weeks, then changed obviously and kept at 0.21 MPa at the end of 12 weeks. CONCLUSIONS: The emulsion blend method is a new method to prepare bone repair materials. As a new bone repair material, PDLLA/HA/DBM is more suitable for regeneration and cell implantation, and the environment during its degradation is advantageous to the growth of bone cells.

Biocompatible Materials↗
PubMed2005

Bone matrix like assemblies of collagen: from liquid crystals to gels and biomimetic materials.

Skeletal tissues associate in close interaction, a dense organic matrix and a mineral network. In bone, the major structural protein is type I collagen, associated with inorganic crystals of hydroxyapatite. The three-dimensional arrangement of collagen fibrils in compact bone forms regularly ordered networks and a parallel was evidenced between these structures and molecular assemblies described in liquid crystals. Similar structures are now obtained in vitro. Indeed, when purified type I collagen is highly concentrated in an acid soluble state, the protein spontaneously assembles into ordered liquid crystalline phases. After a sol/gel transition triggered by pH increase, biomimetic materials are formed which resemble the exact compact bone matrix architecture over distances reaching centimetres and more. The properties of these highly ordered materials will be reviewed recalling their supramolecular arrangement and the corresponding patterns when visualised in polarised light microscopy (birefringence) and transmission electron microscopy (TEM). The association of inorganic phases (amorphous silica) to form chiral hybrid materials will also be described so as the behaviour of cells (fibroblast adhesion and migration) when seeded on these dense biomimetic matrices.

Biomimetic Materials↗
PubMed1999

Determination of bone markers in pycnodysostosis: effects of cathepsin K deficiency on bone matrix degradation.

Pycnodysostosis (Pycno) is an autosomal recessive osteosclerotic skeletal dysplasia that is caused by the markedly deficient activity of cathepsin K. This lysosomal cysteine protease has substantial collagenase activity, is present at high levels in osteoclasts, and is secreted into the subosteoclastic space where bone matrix is degraded. In vitro studies revealed that mutant cathepsin K proteins causing Pycno did not degrade type I collagen, the protein that constitutes 95% of organic bone matrix. To determine the in vivo effects of cathepsin K mutations on bone metabolism in general and osteoclast-mediated bone resorption specifically, several bone metabolism markers were assayed in serum and urine from seven Pycno patients. Two markers of bone synthesis, type I collagen carboxy-terminal propeptide and osteocalcin, were normal in all Pycno patients. Tartrate-resistent acid phosphatase, an osteoclast marker, was also normal in these patients. Two markers that detect type I collagen telopeptide cross-links from the N and C termini, NTX and CTX, respectively, were low in Pycno. A third marker which detects a more proximal portion of the C terminus of type I collagen in serum, ICTP, was elevated in Pycno, a seemingly paradoxical result. The finding of decreased osteoclast-mediated type I collagen degradation as well as the use of alternative collagen cleavage sites by other proteases, and the accumulation of larger C-terminal fragments containing the ICTP epitope, established a unique biochemical phenotype for Pycno.

Acid Phosphatase↗
PubMed1982

Cells of the mononuclear phagocytic system resorb implanted bone matrix: a histologic and ultrastructural study.

Implantation of mineral-containing bone fragments into calvarial defects in rats initiates a rapid and reproducible resorption of the bone matrix. After 7 days, a dense tissue develops with mononucleated as well as multinucleated cells surrounding and between the bone fragments. Electron microscopy revealed that these cells belong to the mononuclear phagocytic system: they were identified as macrophages, epithelioid cells, foreign body giant cells, and Langerhans cells. In addition to the common ultrastructural characteristics, these cells had electron-dense, focal specializations along their cell membrane with a coating on the exterior, corresponding to subplasmalemmal linear densities. Small, unidentified cells with electron-dense ground cytoplasm were often seen in close proximity to more differentiated cells. No halisteresis had occurred on the surfaces of the bone fragments. Indentations resembling Howship's lacunae were frequent; these contained mononucleated as well as multinucleated cells. Some surfaces were frayed and collagen fibers were exposed, but the cells apposed to these surfaces did not have ruffled borders as are seen in osteoclasts. Some bone fragments were broken up and cell processes had penetrated deep into the cracks, separating pieces of matrix. Small matrix particles were phagocytosed by macrophages, but not by epithelioid cells or giant cells. It appears that enzymes capable of degrading bone matrix components were secreted by the more differentiated cells of the mononuclear phagocytic system. They eroded the bone surface in a way reminiscent of osteoclastic bone resorption. They also entered the canaliculi to act from within the bone fragment, a process possible only in dead bone. We suggest a possible relationship of these cells with osteoclasts.

Animals↗
PubMed2003

Healing of large defects treated with calcium sulfate pellets containing demineralized bone matrix particles.

Calcium sulfate (OsteoSet, Wright Medical Technology, Inc, Arlington, Tenn) and calcium sulfate/demineralized bone matrix (DBM) pellets (OsteoSet DBM, Wright Medical Technology, Inc) have been evaluated preclinically in a bilateral medullary defect model of a canine humerus. In this model, both short (6 week) and long (26 week) time points have been evaluated. An analysis of bone response to the pellets was conducted using radiological, histological, mechanical, and quantification techniques. The calcium sulfate/DBM pellets exhibited more rapid trabecular bone remodeling as demonstrated by the absence of the ringlet bone structure typically seen with calcium sulfate pellets. We concluded that calcium sulfate and calcium sulfate/DBM pellets are both effective bone graft substitutes.

Animals↗
PubMed2002

IGF-I and TGF-beta1 application by a poly-(D,L-lactide)-coated cage promotes intervertebral bone matrix formation in the sheep cervical spine.

STUDY DESIGN: A sheep cervical spine interbody fusion model was used to determine the effect of combined insulin-like growth factor-I (IGF-I) and transforming growth factor-beta-1 (TGF-beta1) applied by a poly-(D,L-lactide) (PDLLA)-coated cage. OBJECTIVES: The purpose of this study was to determine the effect of a new PDLLA carrier system, and to evaluate the effect of combined IGF-I and TGF-beta1 application in a sheep cervical spine model. SUMMARY AND BACKGROUND DATA: Growth factors such as bone morphogenic protein-2 have been shown to promote spine fusion and to overcome the disadvantages of an autologous bone graft. The optimum growth factor for promoting spinal fusion and the optimum method for delivering such growth factors are still a matter of discussion. METHOD: In this study, 32 sheep underwent C3-C4 discectomy and fusion: Group 1 (autologous tricortical iliac crest bone graft; n = 8), Group 2 (titanium cage; n = 8), Group 3 (titanium cage coated with a PDLLA carrier; n = 8), and Group 4 (titanium cage coated with a PDLLA carrier including IGF-I [5% w/w] and TGF-beta1 [1% w/w; n = 8). Blood samples, body weight, and body temperature were analyzed. Radiographic scans were performed before and after surgery, then at 1, 2, 4, 8, and 12 weeks, respectively. At the same time points, the disc space height, intervertebral angle, and lordosis angle were measured. After 12 weeks, the animals were killed, and fusion sites were evaluated using functional radiographic views of the animals in flexion and extension. Quantitative computed tomographic scans were performed to assess bone mineral density, bone mineral content, and bony callus volume. Biomechanical testing of the motion segment C3-C4 was performed in flexion, extension, axial rotation, and lateral bending. The stiffness, range of motion, neutral zone, and elastic zone were determined. Histomorphologic and histomorphometric analysis was performed, and polychrome sequential labeling was used to determine the time frame of new bone formation. RESULTS: There were no differences between the groups in terms of blood counts, body weight, and temperature. Over a 12-week period, cage Groups 2 to 4 showed significantly higher values for the intervertebral angle than for the bone graft. Functional radiographic assessment showed significantly lower residual flexion-extension movement in Group 4 than in any other group. The PDLLA-coated cages with IGF-I and TGF-beta1 showed significantly higher values for bone mineral density, bone mineral content, and bony callus volume. The average stiffness in rotation and bending was significantly higher, and the range of motion, neutral zone, and elastic zone in rotation were significantly lower in Group 4 than in any other group. Although only one animal in Group 4 demonstrated solid bony fusion after 12 weeks, histomorphometric evaluation showed a more progressed bone matrix formation in the group that had PDLLA-coated cages with IGF-I and TGF-beta1 than in any other group. Polychrome sequential labeling showed accelerated intervertebral bone matrix formation in Group 4. CONCLUSIONS: The findings showed that PDLLA coating of cervical spine interbody fusion cages as a delivery system for growth factors was effective. Although IGF-I and TGF-beta1 application by a PDLLA-coated interbody cage was not able to achieve solid bony fusion during the 12-week follow-up period, these growth factors significantly increased the results of interbody bone matrix formation. Additional longer-term studies are required to determine whether combined IGF-I and TGF-beta1 application leads to a successful spinal fusion.

Absorbable Implants↗
PubMed2003

A cyclo peptide activates signaling events and promotes growth and the production of the bone matrix.

The interaction of bone cells and their underlying extracellular matrix impacts biological processes such as maintenance of tissue integrity. The biological recognition of the extracellular matrix by attached cells is mediated by the activity of integrins that recognize adhesive-specific domains. The most widely recognized adhesive motif is the RGD sequence, common to many of the adhesive matrix molecules. Here, we show that cyclo DFKRG which was previously selected to increase cell adhesion of human bone marrow stromal cells (HBMSC), increases both cell differentiation and mineralization through activation of tyrosine kinases, focal adhesion kinase (p(125)FAK) and Mitogen Activated Protein (MAP) kinases.

Bone Matrix↗
PubMed2005

[Changes of subtype T lymphocytes in blood after implanting with xenogeneic acellular bone matrix].

OBJECTIVE: To observe the changes of immune status in recipient after implanting with xenogeneic acellular bone matrix (ACBM). METHODS: Twenty rabbits were randomly divided into 4 groups. Autograft, ACBM and bone soaked in alcohol were implanted into the 3 experimental groups separately, and No-treatment was done as control group. The CD4+, CD8+, CD25+ T lymphocytes in blood were detected by flow cytometer at 1, 2, 4 and 6 weeks after operation. After 2 and 6 weeks of implantation, the changes of bone and tissue were observed by histology. RESULTS: After 2-6 weeks, CD4+ and CD8+ T cells were significantly higher in the implanted group of bone soaked in alcohol than that in the other 3 groups (P < 0.05) and there was no statistically significant difference in the other 3 groups (P > 0.05). After 2 weeks, CD25+ T cells were significantly higher in the implanted group of bone soaked in alcohol than that in the other groups. In the 2nd week, there were inflammatory infiltration with a predominance of granulocytes. In the 6th week, there were many fibroblasts instead of granulocytes with a few lymphocytes and cartilage island formed in the implanted groups of autograft and ACBM. CONCLUSION: ACBM implanting has low influence on cellular immunity in recipient.

Animals↗
PubMed2005

Histological evidence of the altered distribution of osteocytes and bone matrix synthesis in klotho-deficient mice.

Mice homozygous for klotho gene deletion are well established aging models as they mimic certain aspects of human senescence e.g. osteoporosis. Induced senescence may affect cellular functions and alter the histological properties of the extracellular matrices. The present study examined the histological and ultrastructural features of osteocytes and the surrounding bone matrix in klotho-deficient mice. As expected, osteoblasts showed a flattened shape with a weak immunoreactivity for alkaline phosphatase, and the bone matrix contained many empty osteocytic lacunae. The walls of both normal and empty lacunae were intensely immunopositive for osteopontin and dentin matrix protein-1, but featured an inconsistent immunoreactivity for osteocalcin and type I collagen. Not surprisingly, TUNEL-positivity, indicative of apoptosis, was found in many osteoblasts, osteocytes, and bone marrow cells of the klotho-deficient mice. In transmission electron microscopy, an amorphous matrix containing non-collagenous organic materials was recognizable around osteoblasts and in the osteocytic lacunae. Some osteoblasts on the bone surface featured these amorphous materials in vacuoles associated with their trans-Golgi network, indicating that, under klotho-deficient conditions, they synthesize and secrete the non-collagenous structures. Some osteocytes displayed pyknosis or degenerative traits. Thus, our findings provide histological evidence that klotho gene deletion influences the spatial distribution of osteocytes and the synthesis of bone matrix proteins in addition to the accelerated aging of bone cells.

Alkaline Phosphatase↗
PubMed1988

Induction of callus formation by implants of bone morphogenetic protein and associated bone matrix noncollagenous proteins.

Callus formation in the periosteal bone interface in response to bone morphogenetic protein (BMP) and associated bone matrix noncollagenous proteins (BMP/NCP) was investigated in mature adult rabbits. For controls byproducts of BMP/NCP purification, bone marrow, eight nonskeletal tissues, purified matrix gamma-carboxyglutamic acid-rich protein (MGP), and a composite of BMP/NCP and polylactic-polyglycolic acid polymer (PLA/PGA) were also implanted in the periosteal bone interface. Quantitative microcomputer image analysis and histologic studies were performed three weeks after the implantation. BMP/NCP and bone marrow or BMP/NCP implanted over a single drill hole into the marrow cavity produced three times more new bone than the bone marrow alone. BMP/NCP alone produced twice as much new bone as bone marrow alone. Control implants of bovine serum albumin or purified MGP produced no new bone. Autogeneic minced muscle and ten nonskeletal tissue controls produced little or no bone formation. Even at one-fifth of the dose of BMP/NCP, a composite of PLA/PGA incorporating BMP/NCP showed almost the same amount of new bone as BMP alone. Histologically, the response to BMP/NCP consisted of an external callus of calcifying cartilage and woven bone. The response to subperiosteal implants of BMP/NCP or BMP/NCP with bone marrow or with minced muscle occurred with the same sequence of developmental events as seen either in embryonic skeletogenesis or in fracture callus.

Animals↗
PubMed2005

Autoregulatory mechanism of Runx2 through the expression of transcription factors and bone matrix proteins in multipotential mesenchymal cell line, ROB-C26.

Runx2 is essential for osteoblast differentiation and gene expression of bone matrix proteins, however, little is known about the mechanism regulating its activity. In this study, the role of Runx2 on gene expression of transcription factors, AJ18, Msx2, and Dlx5, was examined in vitro. It is known that AJ18 and Msx2 act as repressors to inhibit activity of Runx2, whereas Dlx5 promotes its activity. An expression vector inserted Runx2 cDNA was transiently overexpressed in a rat multipotential mesenchymal cell line, ROB-C26 (C26). Real time reverse transcription-PCR analysis showed that, in exogenous Runx2-overexpressing C26 cells (C26-Rx), AJ18 expression increased 1.8-fold, Msx2 expression increased 3.0-fold, and Dlx5 expression increased 2.7-fold compared to the cells transfected with vector alone (C26-Co). Luciferase assay also showed that, in C26-Rx, AJ18 promoter activity increased 2.1-fold compared to C26-Co. Furthermore, gene expression of alkaline phosphatase (ALP) and bone matrix proteins including type I collagen (Col1), osteocalcin (OC), osteopontin (OPN), and matrix Gla protein (MGP) was examined. In C26-Rx, MGP expression increased 1.8-fold, and OPN expression increased 1.4-fold compared to C26-Co. However, no significant difference in Col1, ALP, and OC expressions was detected between C26-Rx and C26-Co. These results suggest that the existence of autoregulatory feed back loops, which inhibit Runx2 activity through the interaction of AJ18, Dlx5, and Msx2 cooperating with that of MGP and OPN, interferes with the differentiation of C26 cells toward mature osteoblasts.

Alkaline Phosphatase↗
PubMed1994

Investigation of an organic delivery system for demineralized bone matrix in a delayed-healing cranial defect model.

The osteogenic potential of demineralized bone matrix (DBM) has been demonstrated in multiple animal models and clinical applications. A particulate form of DBM is generally used to fill defects because it is easily packed into a defect site without operative planning or shaping. One potential disadvantage in the use of a particulate is the migration of particles from the defect site. To stem this, glycerol was added to DBM to improve handling properties. A study was undertaken to compare two forms of DBM with glycerol, with DBM particulate and autograft in a bony defect site. The model chosen consisted of bilateral 8-mm trephine defects created in the parietal skull of 40 rabbits. Animals were sacrificed at 2 and 8 weeks. Results demonstrated both cartilage and bone induction with the three forms of DBM, with 75-90% of the linear width of the defect filled with new bone by 2 weeks. This was similar to the autograft (86%) and significantly greater than the unfilled defects (26%) at 2 weeks. The addition of glycerol to the DBM did not affect the inductive capacity, and produced a response similar to that of DBM particulate alone or autogenous bone.

Animals↗
PubMed2004

Osteocalcin fragment in bone matrix enhances osteoclast maturation at a late stage of osteoclast differentiation.

Although 14-day-old mouse embryonic calvarial cells cultured in plastic culture dishes in the presence of 1alpha,25-dihydroxyvitamin D3[1alpha,25-(OH)2D3] for 7 days could barely resorb bone slices, the same calvarial cells cultured with an ethylenediaminetetraacetic acid (EDTA) extract from bovine bone powder under the same conditions stimulated pit formation on bone slices in a dose-dependent manner. Therefore, the present study was conducted to purify and characterize this osteoclast maturation-inducing factor(s) from the bone matrix. The protein having osteoclast maturation-inducing activity in the EDTA extract was purified by gel filtration over Superdex 75 preparation grade and chromatography on hydroxyapatite, Mono Q, and C8 reversed-phase HPLC by monitoring the ability of the eluted fractions to elicit pit formation on bone slices. The molecular weight of the purified protein estimated by high-resolution polyacrylamide gel electrophoresis was 5.7 kDa and 6.8 kDa in the respective absence and presence of 2-mercaptoethanol. The sequence of the 30-amino-acid purified protein corresponded to the 7th to 36th residues of bovine osteocalcin. The osteocalcin fragment, missing the initial 6 residues at the N-terminal region, exhibited higher osteoclast maturation-inducing ability than bovine intact osteocalcin on a per weight basis. The osteocalcin fragment had no effect on the expression of receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) and osteoprotegerin (OPG) genes in calvarial cells, nor did it enhance the bone-resorbing activity of mature osteoclasts. When the osteocalcin fragment was added to late-stage (days 4-7) or to early-stage (days 0-3) cultures of calvarial cells pretreated with 1alpha,25-(OH)2D3, its stimulatory effect was observed in the late-stage cultures rather than in the early-stage ones. In addition, the osteocalcin fragment directly enhanced the formation of osteoclasts with bone-resorbing ability from Mac-1+ c-Fms+ cells in the presence of macrophage colony-stimulating factor (MCSF) and RANKL. These results suggest that the osteocalcin fragment in bone matrix is involved in osteoclast maturation, especially at a late stage of osteoclast differentiation.

24,25-Dihydroxyvitamin D 3↗
PubMed1998

Bacteria inhibit biosynthesis of bone matrix proteins in human osteoblasts.

The effect of extracts from Staphylococcus aureus and Staphylococcus epidermidis on bone matrix production were assessed by analyzing the biosynthesis of osteocalcin and Type I collagen in a human osteoblastic osteosarcoma cell line (MG-63). In MG-63 cells, extracts from Staphylococcus aureus and Staphylococcus epidermidis decreased 1,25(OH)2-vitamin D3 stimulated osteocalcin biosynthesis, and insulin-like growth factor I induced production of Type I collagen in a concentration dependent manner. The basal rate of osteocalcin and Type I collagen formation was unaffected by the bacterial extracts. The inhibitory effect of the bacteria on osteocalcin biosynthesis was seen after 24 hours of treatment and was maintained for at least 96 hours. The extracts of Staphylococcus aureus and Staphylococcus epidermidis enhanced prostaglandin E2 formation in the MG-63 cells. Abolition of the prostaglandin E2 response by treatment with indomethacin and flurbiprofen did not affect bacteria induced inhibition of osteocalcin production. Stimulation of osteocalcin biosynthesis by 1,25(OH)2-vitamin D3 was associated with a decreased rate of cell proliferation. The inhibitory action of the bacterial extracts was not linked to any inhibition of [3H]-thymidine incorporation into deoxyribonucleic acid. These data show that extracts of Staphylococcus aureus and Staphylococcus epidermidis have the ability to inhibit the biosynthesis of bone matrix proteins by a nonprostaglandin and noncytotoxic dependent mechanism and suggest that bone loss in inflammatory processes containing Staphylococcus aureus or Staphylococcus epidermidis may not be caused only by enhanced bone resorption but also by decreased bone formation.

Calcitriol↗
PubMed1993

Demineralized bone matrix. Enhancement of spinal fusion.

A study was conducted to determine the ability of demineralized bone matrix gel to act as an osteoconductive/osteoinductive material to enhance canine spinal fusion. Seven dogs underwent posterior spinal fusion. Four-level fusions were performed with one of four procedures at each level: decortication alone, with gel added, with autograft, or with both gel and autograft. Dogs were killed at 6 weeks and early histologic response was studied. At untreated control sites, little bone formation was evident. Gel-filled sites showed abundant osteoid, with 60% of demineralized particles fused to or surrounded by new bone. Sites filled with autograft had more new bone, but there was more osteoid at gel-treated sites. Autograft augmented with gel showed the most vigorous response, with extensive bridging between demineralized particles, host bone, autograft, and new bone. Significantly less autograft was needed to induce a similar amount of new bone formation when gel was added. Use of the gel as an autograft extender may improve the chance for successful spinal fusion.

Animals↗
PubMed2002

[Experimental study of periosteal osteoblasts coculture with freeze-dried demineralized bone matrix].

OBJECTIVE: To investigate the feasibility of freeze-dried demineralized bone matrix (FDBM) as scaffold material in bone tissue engineering. METHODS: Osteoblasts which were isolated from cranial periosteum of New Zealand rabbits were cultured as the seeding cells, then the cells were cocultured with heterogenous FDBM in vitro. The cell-material complex was observed under phase microscope, light microscope and electronic scanning microscope in order to evaluate the interaction between cells and FDBM. RESULTS: Eight hours after coculture, the osteoblasts adhered to FDBM scaffolds. Seven days later, the osteoblasts differentiated and proliferated in FDBM network. Extracellular matrix was secreted and calcium nodes were formed among osteoblasts. CONCLUSION: FDBM is a good scaffold material for the bone tissue engineering.

Animals↗