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PubMed2003

The influence of nacre surface and its modification on bone apposition: a bone development model in rats.

BACKGROUND: Bone graft substitutes are currently used individually or in various combinations in reconstructing bone defects. Nacre, marine mineralized structure, was recently proposed as a very biocompatible and osteoinductive material for use in periodontal and implant surgery. Our aim was to investigate the interaction between natural nacre and fresh bone marrow, during bone development, in an ectopic site of DA rats. Surface modifications of nacre were tested. METHODS: Demineralized bone matrix (DBM) cylinders (demineralized cortex of diaphysis) prepared from rat femurs were filled with fresh marrow, which was removed from other 2-month old DA rat femurs. Natural nacre particle or nacre which was treated with HCl, phosphate buffer saline (PBS), and Ca(OH)2 to modify its surface was placed into the DBM cylinders. The cylinders were implanted subcutaneously at the thoracic region of growing DA rats. After 4 weeks the cylinders were surgically removed, fixed in buffered formalin, and x-rayed. Scans of the microradiographs and histological evaluation of the DBM cylinders including bone developed at the interface of nacre and its surface modifications were compared to marrow controls. RESULTS: The results show that natural nacre is a poor conductive biomaterial in a bone developmental environment. Nacre surface treated with Ca(OH)2 and PBS was found to be most biocompatible. In this group, new bone was apposed directly on the nacre surface and the total amount of bone was highest in comparison to other treatment groups. CONCLUSIONS: This study does not support previous observations that nacre is osseoinductive. Our model system seems to be very sensitive and capable of testing interaction between surface modifications of biomaterials and fresh marrow in the process of new bone development.

Analysis of Variance↗
PubMed2003

Strain-derived canalicular fluid flow regulates osteoclast activity in a remodelling osteon--a proposal.

The concept of bone remodelling by basic multicellular units is well established, but how the resorbing osteoclasts find their way through the pre-existing bone matrix remains unexplained. The alignment of secondary osteons along the dominant loading direction suggests that remodelling is guided by mechanical strain. This means that adaptation (Wolff's Law) takes place throughout life at each remodelling cycle. We propose that alignment during remodelling occurs as a result of different canalicular flow patterns around cutting cone and reversal zone during loading. Low canalicular flow around the tip of the cutting cone is proposed to reduce NO production by local osteocytes thereby causing their apoptosis. In turn, osteocyte apoptosis could be the mechanism that attracts osteoclasts, leading to further excavation of bone in the direction of loading. At the transition between cutting cone and reversal zone, however, enhanced canalicular flow will stimulate osteocytes to increase NO production, which induces osteoclast retraction and detachment from the bone surface. Together, this leads to a treadmill of attaching and detaching osteoclasts in the tip and the periphery of the cutting cone, respectively, and the digging of a tunnel in the direction of loading.

Biomechanical Phenomena↗
PubMed2005

Extractable bone morphogenetic protein and correlation with induced new bone formation in an in vivo assay in the athymic mouse model.

A correlation between extractable bone morphogenetic proteins (BMPs) in demineralized bone matrix (DBM) and osteoinduction has been suggested. Extractable BMP-4 and osteoinductivity of DBM from 40 donors were assessed using enzyme-linked immunosorbent assay (ELISA) and in vivo athymic mouse assay, respectively. Extractable BMP-4 level averaged 3.7 +/- 0.21 ng/g of DBM and correlated with osteoinductivity of the DBM in an in vivo assessment of induced newbone formation.

Animals↗
PubMed1993

Reconstruction of the growing cricoid with a composite graft of demineralized bovine bone and autogenous perichondrium; a comparative study in rabbits.

In growing rabbits, the feasibility of a new type of composite graft for the reconstruction of defects in the cricoid ring is studied. This graft consists of Demineralized Bovine Bone matrix (DBBM) enfolded in a perichondrial flap. The cartilage formed in the DBBM by cells, derived from the perichondrium, is demonstrated to provide a valuable substitute for resected parts of the cricoid. A specific feature of this reconstruction is that it allows further growth and does not result in a secondary stenosis during later development.

Animals↗
PubMed1995

Antiinflammatory drug effects on bone repair and remodeling in rabbits.

Ketorolac and methylprednisolone effects on bone repair were studied. Demineralized bone matrix was used to graft the defects of rabbits' ulnae. Twenty-seven rabbits were divided into 4 groups: Group A (control group; no drug treatment), Group B (treated with ketorolac 2 mg/kg body weight daily), Group C (treated with ketorolac 4 mg/kg body weight daily), and Group D (treated with methylprednisolone 1 mg/kg body weight weekly). Drug treatment was continued for 6 weeks. The biomechanical results indicated methylprednisolone significantly deteriorated the mechanical properties of the grafted ulnae and the contralateral intact ulnae, although the effects were more pronounced in the grafted side. In Group B, there was minimum effect of ketorolac on the bone properties. In Group C, ketorolac significantly decreased the torsional stiffness and energy absorption of the grafted ulnae and also decreased the maximum torque in the intact and the grafted bones. It was concluded that the inhibitory effect of ketorolac on bone repair was dose dependent. In comparing the effects of ketorolac and methylprednisolone, the latter is more pronounced on torsional stiffness, but the effects on maximum torque and energy absorption were similar to ketorolac. The mechanism of the effects of ketorolac needs additional investigation.

Animals↗
PubMed1992

Giant cell tumor of bone treated by curettage, cementation, and bone grafting.

Giant cell tumor, a relatively rare, occasionally malignant tumor of bone, remains a difficult therapeutic problem for the orthopedic surgeon. Various treatment options, including curettage alone, curettage with bone grafting, radiation, and curettage with acrylic cementation have been utilized and reported. Therapeutic complications such as infection, recurrence, and loss of support of the articular surface have continued to plague the treatment of giant cell tumors. This article reports the results of 10 consecutive cases of giant cell tumor of bone treated by curettage and methyl methacrylate cementation, followed by bone grafting of the surface of the lesion with demineralized bone matrix to reconstitute the cortex at the site of the tumor. At an average follow up of 36 months, eight patients had an excellent functional result and two had a fair result as scored on the Musculoskeletal Tumor Society rating system. To date, there have been no tumor recurrences or metastases, and all patients have radiographic evidence of healing of the weight bearing cortical surface.

Adult↗
PubMed2001

Cathepsin K in aseptic hip prosthesis loosening: expression in osteoclasts without polyethylene wear particles.

OBJECTIVE: To investigate the expression of the bone matrix degrading cysteine proteinase cathepsin K and to determine the colocalization of cathepsin K with polyethylene (PE) particles in tissue specimens of patients with aseptic hip prosthesis loosening (AHPL). METHODS: The expression of cathepsin K was studied by immunohistochemistry in tissue specimens of 9 patients with aseptically loosened acetabular components of failed cementless total hip replacements. The expression of cathepsin K was compared to that of the macrophage marker CD68 by serial section analysis. Double labeling of the expression of cathepsin K or CD68 by immunohistochemistry and of PE particles by modified Oil Red staining method was performed. RESULTS: Cathepsin K could be predominantly detected in osteoclasts attached to the bone tissue, while only a few (CD68+) mononuclear and multinucleated foreign body giant cells (MGC) were positive for this enzyme. By double labeling with Oil Red staining we found the majority of CD68 positive cells of the periprosthetic tissue that were colocalized with PE particles. However, cathepsin K-expressing osteoclasts could not be stained with Oil Red. CONCLUSION: The present data suggest that in AHPL neither mononuclear cells nor MGC but rather osteoclasts are mainly involved in cathepsin K mediated bone matrix destruction. Using double labeling of immunohistochemistry and Oil Red staining we observed that the cathepsin K-expressing osteoclasts did not include PE particles.

Acetabulum↗
PubMed2001

Role of cartilage-derived anti-angiogenic factor, chondromodulin-I, during endochondral bone formation.

OBJECTIVE: Cartilage is a typical avasclar tissue that exhibits powerful resistance to angiogenesis or vascular invasion. We previously identified a cartilage-specific 25 kDa glycosylated protein, chondromodulin-I (ChM-I), as anti-angiogenic factor. Taking advantage of ectopic bone formation and xenograft tumour model by human chondrosarcoma cell line OUMS-27, we examined how ChM-I is involved in switching of angiogenesis in cartilage. DESIGN: Gene expression pattern of ChM-I was examined in 4-week-old mice and mouse embryos by northern blot analysis and in situ hybridization. To evaluate the effect of ChM-I on ectopic bone formation, guanidine extracts of demineralized bone matrix were mixed with the ChM-I-bound heparin-Sepharose beads and were implanted onto the fasciae of back muscle of 6-week old nude mice. To analyse the effect of ChM-I on tumour angiogenesis, the level of ChM-I mRNA in cartilaginous tumours was assessed by competitive PCR, and compared with that of articular cartilage. Then, human chondrosarcoma OUMS-27 cells were inoculated into the back of nude mice to form a tumour about 45 mm3 in size. Recombinant ChM-I protein was administrated into OUMS-27 xenograft tumours for the initial 5 days to study its effect against tumour-angiogenesis. RESULTS: ChM-I gene was specifically expressed in cartilage of 4-week-old mice. Eye and thymus were also identified as minor expression sites. However, during endochondral bone development, cartilage changes its character from anti-angiogenic into angiogenic prior to the replacement of calcified cartilage by bone. In embryos, ChM-I mRNA was expressed in proliferative and upper hypertrophic cartilage zones in the developing cartilaginous bone rudiments, but completely abolished in lower hypertrophic and calcified cartilage zones. Purified ChM-I protein apparently inhibited vascular invasion into cartilage induced by the implantation of demineralized bone matrix in nude mice, leading to the inhibition of replacement of cartilage. The level of ChM-I transcripts in the lower-grade chondrosarcomas was substantially reduced to several hundreds or less in the lower-grade chondrosarcomas, compared with that of articular cartilage or other benign cartilage tumours. The local administration of recombinant human ChM-I almost completely blocked tumour angiogenesis and growth in the human chondrosarcoma xenografts in mice. CONCLUSIONS: ChM-I is involved in the anti-angiogenic property of cartilage and its absence creates a permissive microenvironment for vascular invasion into cartilage under physiological and pathological conditions.

Animals↗
PubMed1985

Osteonectin and Gla-protein in calf bone: ultrastructural immunohistochemical localization using the Protein A-gold method.

Osteonectin and bone Gla-protein have been localized at the ultrastructural level in calf scapula bone tissue. Post-embedding-decalcified thin sections of paraformaldehyde-fixed and Araldite-embedded specimens of calf scapula were incubated with rabbit antisera to bovine osteonectin and bone Gla-protein, and the sites of antigen-antibody reaction were demonstrated using the Protein A-gold technique. Specific labelling of the bone matrix was obtained with both antisera. The collagen fibers were labelled particularly intensely. Filamentous structures visible at the sites of early mineralization were labelled by rows of gold particles after incubation with anti-osteonectin antiserum. These findings are consistent with biochemical data available on the localization and properties of these non- collagenous proteins. 'Crystal ghost'-like structures are immunoreactive to anti-osteonectin antiserum.

Animals↗
PubMed1992

[Pathological changes induced by environmental chemical pollutants in tissues of the locomotor system].

The most widespread contaminants that accumulate in the environment due to the activity of man are mercury, lead, phenol and sulphur compounds. They have a harmful effect on the body and to an even greater extent on its progeny. A study was made of structural and functional changes in supporting (hyaline cartilage, bone) and hemopoietic (bone marrow) tissues under conditions of lead and phenol poisoning of albino rats and guinea pigs. The methods applied were histochemistry, historadiography, and electron microscopy. It has been established that lead can be accumulated by tissues (particularly by cartilage and bone), inducing disorders of plastic and energy metabolism in the cell. This is attended by the growth delay, osteoporosis and inhibition of normal and reparative osteogenesis. The toxic effect of phenol on the cells manifests by inhibition of the enzymic activity; there is evidence of disturbance of oxidative phosphorylation and of the mechanisms of specific biosynthesis and energy metabolism in the cells. Under conditions of phenol intoxication the chondrocytes and osteoblasts show disorders in the biosynthesis of collagen and sulphated glycosaminoglycans with an evident disproportion of their macromolecules in the cartilage and bone matrix.

Animals↗
PubMed1980

Hemopoiesis in demineralized bone allografts.

Demineralized allogeneic bone matrix (DBM), implanted in muscle, induces the formation of an ossicle within which histologically recognizable hemopoietic tissue develops. Analyses of rabbit ossicle marrow in a methylcellulose culture system demonstrated the presence of committed hemopoietic precursors; colony-forming units in culture (CFUC), erythroid colony-forming units (CFUE) and erythroid burst-forming units (BFUE) by six weeks post-implantation. The time courses of colony and burst formation by progenitor cells of ossicle and femoral marrow were similar. Induction of hemolytic anemia by phenylhydrazine hydrochloride at six weeks post-DBM implantation showed that the ossicle marrow was responsive to systemic erythropoietic stimuli. The DBM implant may provide a unique model for studying the development of hemopoietic microenvironments within bone.

Animals↗
PubMed1990

Posterior cervical spine stabilization under local anesthesia.

A technique is described for posterior cervical stabilization with spinous process wiring and fusion performed with the patient under local anesthesia and using corticocancellous demineralized bone matrix allograft. In patients with unstable cervical spines, posterior stabilization and fusion with local anesthesia allowed patient interaction with the surgeon during crucial parts of the operation. The technique was well tolerated and no untoward complications occurred. The technique has not been described for the neurologically intact patient with cervical spine trauma. The purpose of this report is to document the facility and advantages of this technique over traditional general anesthesia with autograft use. Nineteen patients were treated surgically at the author's institution. Local anesthesia was used in 12, and general anesthesia was used in 7. Allograft was used in 12 and autologous iliac crest graft was used in 7 patients. The indications for surgery were instability or neurologic deficit. Blood loss and operative times were favorable when compared with general anesthesia and autograft. The fusion extended by one level in 6 of 19 patients. One patient had preoperative neurologic deficit. All 19 follow-up patients were Frankel grade E. There is no need for endotracheal intubation, the patient serves as his or her own spinal cord monitor, and the surgeon is able to be aware immediately of any threat to neurological function. Demineralized bone matrix allograft has been shown to effectively induce osteogenesis by osteoinduction as well as osteoconduction. Its use eliminates the need for autograft harvesting and permits the use of local anesthesia alone for cervical spine posterior stabilization. The more neurologically intact the patient, the more this technique is indicated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2002

Resorbable posterolateral graft containment in a rabbit spinal fusion model.

OBJECT: The authors studied the effect of a resorbable graft containment device in a rabbit posterolateral lumbar spinal fusion model. METHODS: Twenty rabbits were divided into four groups: autologous bone graft (ABG), ABG with the MacroPore containment device (ABG + MP), demineralized bone matrix (DBM), and DBM with the containment device (DBM + MP). Fusion mass was assessed at 6 weeks with high-resolution radiography and volumetric computerized tomography. The graft containment device was associated with alteration of the fusion mass structure and significant enhancement of fusion mass volume (ABG versus ABG + MP, p = 0.027; DBM versus DBM + MP, p = 0.043). CONCLUSIONS: A bioabsorbable protective graft containment device successfully enhanced posterolateral spinal fusion mass volume.

Absorbable Implants↗
PubMed2002

Immunohistochemical examination on intracranial calcification in neurodegenerative diseases.

Fahr-type calcification is a relatively common finding in the elderly, and in younger patients with Alzheimer's disease, calcification in the basal ganglia is not uncommon. However, as far as we know, an immunohistochemical study of intracranial calcification in neurodegenerative diseases has not been performed. In this study, we examined intracranial calcification of the basal ganglia and cerebellum with antibodies against noncollagenous bone matrix proteins. Nineteen brains were employed. The diagnoses were diffuse neurofibrillary tangles with calcification in five, Alzheimer's disease in five, Pick's disease in one, progressive supranuclear palsy in one, Parkinson's disease in one, and six controls. By conventional histology, three patterns of calcium (Ca) deposition were recognized: diffuse deposition within the tunica media of small and medium-sized vessels (type 1 deposition), free spherical or lobulated concretions (type 2 deposition) in the parenchyma, and rows of small calcospherites lying along capillaries (type 3 deposition). Type 3 deposition is relatively rare, and may be a hallmark of severe intracranial calcification. Immunohistochemistry demonstrated that osteopontin was present diffusely in all Ca deposition types. Osteocalcin was present chiefly in the peripheral region of type 2 and 3 depositions, as well as in only the rims of type 1 deposition. Bone sialoprotein and osteonectin were found only in the core portions of type 2 and 3 depositions. In brief, type 1 deposition shows a different staining pattern from type 2 and 3. Different Ca deposition patterns of noncollagenous bone matrix proteins may suggest their separate roles in the pathogenesis of intracranial calcification.

Aged↗
PubMed1993

Immediate reconstruction of massive cranio-orbito-facial defects with allogeneic and alloplastic matrices in baboons.

40 cranio-orbito-facial osseous defects were created in 20 adult male baboons (Papio ursinus) to test the effectiveness of an allogeneic and an alloplastic matrix implant for the functional and morphological repair of the disassembled craniofacial complex. In each animal, one defect was reconstructed with a craniofacial bone segment harvested from donor adult baboons, and processed so as to obtain autolysed antigen-extracted allogeneic (AAA) bone matrix, preserving the bone morphogenetic protein (BMP) activity essential for bone induction. The contralateral defect was implanted with spherical macrobeads of polymethylmethacrylate (PMMA) coated with poly-2-hydroxyethylmethacrylate (PHEMA), and sintered into a porous molded implant, replicating the structural anatomy of the avulsed osseous segment. Histological analysis was carried out on undecalcified and decalcified bone sections prepared from specimens harvested at 3, 6 and 12 months after surgery. In AAA bone, the morphogenetic response was characterized by vascular invasion and mesenchymal cell aggregation after partial resorption of the implanted matrix. This was followed by bone deposition at the osteotomy interfaces and within the medullary spaces of the implanted AAA bone. Although bone ingrowth did occur in some PMMA/PHEMA specimens, the majority of implants showed fibrous union at the recipient interfaces. The limited bone ingrowth may be related to narrow interconnections between larger porous spaces after chemical synthesis of the two polymeric components. Osteogenesis in AAA bone appeared consistent with osteoconductive invasion from the viable bone at the recipient interfaces. In addition, the finding of a delicate trabecular-like bone, appositional to the central areas of the implanted matrix, suggests bone formation by induction.

Animals↗
PubMed1994

The effect of recombinant human osteogenic protein-1 on healing of large segmental bone defects.

A rabbit ulnar non-union model was used to evaluate the effect of recombinant human osteogenic protein-1 on the healing of a large segmental osteoperiosteal defect. A 1.5-centimeter segmental defect was created in the mid-part of the ulnar shaft of adult rabbits. The defect was filled with an implant containing either recombinant human osteogenic protein-1 or naturally occurring bovine osteogenic protein. The recombinant human osteogenic protein-1 implants consisted of a carrier of 125 milligrams of demineralized, guanidine-extracted, insoluble rabbit bone matrix (the collagen carrier), reconstituted with 3.13, 6.25, 12.5, twenty-five, fifty, 100, 200, 300, or 400 micrograms of recombinant human osteogenic protein-1. Animals that received recombinant human osteogenic protein-1 were compared with animals that received an implant of 250 micrograms of a preparation of naturally occurring bovine osteogenic protein mixed with the collagen carrier. Limbs that served as controls received either the collagen carrier alone or no implant at all. The treated and the untreated defects were examined radiographically and histologically at eight or twelve weeks after implantation. Mechanical testing was performed on six animals. All implants of recombinant human osteogenic protein-1, except for those containing 3.13 micrograms of the substance, induced complete radiographic osseous union within eight weeks. The defects that were treated with an implant of bovine osteogenic protein also healed within this time-period. The bone induced by both types of implants had new cortices with advanced remodeling and marrow elements. Histological evaluation of this new bone at eight weeks postoperatively revealed primarily lamellar bone, with the formation of new cortices and normal-appearing marrow elements. The average torsional strength and energy-absorption capacity of the union induced by recombinant human osteogenic protein-1 was comparable with that of intact bone. The control defects that had been implanted with collagen carrier alone and those with no implant showed no bridging of the defect.

Animals↗
PubMed2000

N-Glycan structures of an osteopontin from human bone.

N-Glycan structures of osteopontin (a bone matrix protein) from human bone (lumbar vertabrate) are reported in detail. Asn-linked glycan portion was released from 100 microg of osteopontin by digestion with glycoamidase A (from sweet almond), and the reducing ends of the N-glycans were reductively aminated with 2-aminopyridine. The derivatized N-glycans were separated and structurally identified by a multidimensional mapping technique on HPLC columns. Two major N-glycan structures were also confirmed by mass spectrometry. The proposed structures are shown below. The result should permit future comparison with the N-glycan structures of osteopontins obtained from other sources (kidney tissues, macrophages, urinary stones, human milk, etc.).

Aminopyridines↗
PubMed1975

Electron microscopie and enzyme cytochemical studies on the guinia pig metaphysis with special reference to the lysosomal system of different cell types.

A transmission electron microscopic study of demineralized, methaphyseal bone of the young guinea pig is presented. Special attention is paid to the lysosomal system of the different cell types. Visualization of acid phosphatase and aryl sulfatase activity was used to identify tissue components as belonging thereto. The distribution of alkaline phosphatase activity, a plasma membrane marker, was also examined. Osteoblasts were distinguished by a marked development of the granular endoplasmic reticulum and the Golgi complex. Perivascular cells type A, morphologically resembled the osteoblasts, and are believed to represent an early stage in the specialization of the latter. A few lysosomes were normally found in the osteoblasts; they were less common in the type A cells. In contrasts to their regular occurrence in guinea pig epiphyseal cartilage, dense bodies of lysosomal nature ("type I vesicles") were only rarely seen in the bone matrix. Structures analogous to the type II vesicles in cartilage were, however, normally present. Their membrane showed activity of alkaline phosphatase. Possible functions of lysosomes and matrix vesicles in osteogenesis are discussed. Perivascular cells type B and chondroclasts both contained a prominent Golgi complex and large numbers of free ribosomes, mitochondria and lysosomes. In the type B cells, inclusion material of varying appearance often occurred in the lysosomes and in endocytic vesicles. The chondroclasts sometimes presented a ruffled border, with associated vacuoles and lysosomes in the subjacent cytoplasm. It is suggested that both cell types participate in the resorption of the epiphyseal cartilage. Chondroclasts presumably arise by fusion of type B cells and/or monocytic precursors from the peripheral blood.

Acid Phosphatase↗