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At least 37 records · Page 2Linked to original sources
PubMed1989

Clinical induction of bone repair with demineralized bone matrix or a bone morphogenetic protein.

Treatment of orthopaedic lesions through induction of bone regeneration has produced promising results in laboratory animals and preliminary human trials. Both demineralized bone powder and bone morphogenetic protein (BMP) are being used clinically to treat bony defects without the need for an autogenous bone harvesting procedure. The historical perspective and laboratory rationale for osteoinduction is presented, as well as current and future clinical applications of demineralized bone powder and BMP.

Animals↗
PubMed1991

Influence of parathyroidectomy, 1,25-dihydroxyvitamin D3 and high dietary calcium intake on demineralized bone matrix powder-induced bone formation in the rat.

Demineralized bone matrix induces ectopic endochondral bone formation. We used this model to study the effect of parathyroidectomy (PTX), 1,25-dihydroxyvitamin D3 treatment, and calcium enriched diet on bone formation in the rat. Hypocalcemia and hyperphosphatemia in PTX rats were corrected by 1,25-dihydroxyvitamin D3 treatment (2 x 12.5 ng/day) or by calcium enriched diet (3% calcium). Serum 1,25-dihydroxyvitamin D3 concentration was decreased in PTX rats and in intact rats with high dietary calcium intake. Calcium content of ectopic new bones (42 days after bone matrix implantation) was reduced in PTX rats compared with intact control rats. This could be prevented by 1,25-dihydroxyvitamin D3 treatment. In contrast, calcium enriched diet led to diminished mineralization of ectopic bones both in intact and PTX rats. We conclude that the effect of parathyroidectomy on bone formation may be mediated by 1,25-dihydroxyvitamin D3. 1,25-Dihydroxyvitamin D3 directly stimulates bone formation in this model and this effect is not simply the result of increasing serum calcium concentration.

Animals↗
PubMed1987

Nature of bone morphogenetic protein (BMP) from decalcified rabbit bone matrix.

Rabbit bone morphogenetic protein (BMP) from demineralized and defatted rabbit bone matrix was partially purified. BMP activity was examined by the implantation of fractionated materials into the thigh muscle pouch of the mouse. Rabbit BMP was solubilized by both 4M guanidine hydrochloride (GuHCl) and 6M urea solutions. Crude BMP had isoelectric point precipitation at pH 3 in 6M urea and showed bone morphogenesis. Fractions eluted with 0 and 0.2 N NaCl in DEAE CL-6B ion exchange chromatography showed bone morphogenesis in each individual pH of pH 4 to pH 7 but the fraction eluted with 1.0 N NaCl did not show any activity. Sephadex G-75 filtration separated the crude material into three peaks and the peak of about 23,000 showed bone morphogenesis. In sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and isoelectric focusing, rabbit BMP was thought to be an acidic protein having a molecular weight of 24,000 with an isoelectric point around 4.85.

Animals↗
PubMed1989

Affinity of osteogenin, an extracellular bone matrix associated protein initiating bone differentiation, for concanavalin A.

Subcutaneous implantation of demineralized bone matrix results in bone differentiation. The bone inductive protein, osteogenin, was isolated recently by heparin affinity chromatography. The affinity of osteogenin for various lectins was examined to attain further purification and characterization. Osteogenin extracted from bovine bone matrix binds to concanavalin A (Con A) but not to wheat germ agglutinin or soybean lectin. The present data indicate that the bone inductive protein, osteogenin, is a glycoprotein. The use of a Con A Sepharose affinity column followed by preparative gel electrophoresis resulted in a greater than 250,000 fold purification of osteogenin.

Animals↗
PubMed1979

Effect of preimplantation treatment on the bone-forming potential of decalcified allogeneic and xenogeneic bone-matrix implants.

Bone-forming property of 0.6 M HCl decalcified (a) allogeneic bone matrix preserved in 70% alcohol, (b) allogeneic bone matrix preserved in anaesthetic ether, (c) allogeneic 'Ossein' provided by the Leather Research Institute, Madras, and (d) xenogeneic bone-matrix preserved in alcohol was studied by fitting the implants in surgically created complete circumferential osteo-periosteal gaps in the ulna of rabbits. Bone formation was assessed radiologically, macroscopically, histologically, and by tetracycline fluorescence up to 16 postimplantation weeks. Successful bridging of the gap by new bone formation was observed in 75% of (a) and 28.6% of (d) preserved up to 2 weeks. Ether-preserved implants did not induce bone formation. The 'Ossein' implants remained as inert material neither invaded by host cells nor inducing any bone formation. The xenogeneic implants exhibited local immune response which was probably responsible for poor osteogeneic response. Bone forming quality of bone-matrix implants appears to be influenced by the chemical treatment during preparation and preservation, host cellular response and immune reaction invoked by the implant.

Animals↗
PubMed1986

The effect of decalcified bone matrix on the osteogenic potential of bone marrow.

Rabbit bone marrow cells were cultured in diffusion chambers with or without decalcified bone matrix. The chambers were assayed after 28 days for alkaline phosphatase activity, deoxyribonucleic acid (DNA), calcium, and phosphorus contents. Morphologically, marrow cells incubated with or without matrix differentiated to form bone and cartilage. With bone matrix, the calcium and phosphorus contents of chambers were significantly higher than control chambers. Alkaline phosphatase activity and DNA content were not influenced by inclusion of bone matrix. These results indicate that bone matrix constituents exert a stimulatory effect on bone formation from marrow cells. This osteogenic stimulation could be due to the influence of an osteoinductive factor and/or to stimulation of osteoprogenitor cells known to be present in the marrow.

Alkaline Phosphatase↗
PubMed1988

Localization of 99mTc-diphosphonates in newly formed bone matrix as a measure of bone lesion detectability.

The lesion-to-normal-bone ratios of DBA-MDP (dibutylamino-methylene-diphosphonate), DPD (dicarboxypropane-diphosphonate) and MDP (methylene-diphosphonate) each labeled with 99mTc, were evaluated in experimental bone lesions. In 3-day old lesions this ratio was increased twofold for DBA-MDP in comparison with MDP and DPD which showed nearly equal ratios. Later on these differences became negligibly small. It is concluded that 99mTc-DBA-MDP is fixed more strongly in the immature bone matrix and that this will lead to an improvement in the detectability of lesions containing larger amounts of immature bone matrix.

Animals↗
PubMed1991

Decreased osteoinductive potential of bone matrix from ovariectomized rats.

The effect of estrogen deficiency on matrix-induced bone formation was investigated. Female rats were ovariectomized and given demineralized bone matrix (DBM) intramuscularly 3 weeks before termination. The DBM was taken from previously ovariectomized and from sham-operated on rats. The animals were killed at various times after ovariectomy (6-27 weeks). Implants were processed undemineralized for histologic and biochemical studies. Normal DBM implanted in ovariectomized or normal rats induced extensive bone formation 6 weeks postovariectomy. The amount of newly formed bone decreased with the age of host rats. Bone matrix taken from ovariectomized rats was incompletely resorbed in both ovariectomized and normal hosts, therefore reducing the extent of osteogenesis and bone-marrow formation. Instead, chondrogenesis was intensive, but delayed. The calcium, magnesium, and zinc contents were decreased in implants taken from ovariectomized rats when compared with implants taken from normal animals. Normal osteoinduction with DBM taken from normal rats and implanted in ovariectomized rats and the absence of osteogenesis with DBM taken from ovariectomized rats indicate that an estrogen-deficient environment is not crucial for altered matrix-induced endochondral bone formation in ovariectomized rats. An altered composition of matrix from ovariectomized rats and a subsequent abnormality in the cell-matrix interaction should be considered responsible.

Animals↗
PubMed1990

BAPN dose dependence of mature crosslinking in bone matrix collagen of rabbit compact bone: corresponding variation of sonic velocity and equatorial diffraction spacing.

Crosslinking density in demineralized bone matrix collagen was found to depend on the beta-aminopropionitrile (BAPN) dose level for compact bone from rabbit femurs. The dependence was demonstrated for the hydroxypyridinium (HP) concentration, a mature crosslink. A more consistent dependence on BAPN dosage was observed for the fraction of the demineralized bone matrix insoluble in 0.5 M acetic acid (AIF) corresponding to the remaining crosslinked collagen. The average HP concentration in 21 week old controls was 0.24 moles HP/mole collagen which decreased to 0.13 +/- 0.04 for the same age rabbits dosed with 1 gm BAPN/kg/day for 13 wks. The comparable mean AIF values were 0.91 for controls and 0.75 for maximum dose level. Most of the effect of BAPN on crosslinking was observed at the lower dosages below 0.2 g/kg/day. On the other hand, overt osteolathyritic symptoms are seen only for BAPN dosages greater than 0.2 g/kg/day. The mean sonic plesio-velocity was previously found to decrease from 3.4 to 3.03 km/sec as the BAPN dosage was increased. A similar close relationship was discovered for the equatorial diffraction spacing in fully mineralized bone which increased from 1.235 for normal rabbit bone to 1.28 nm for maximum dose. Most of the effect on these physical properties is exhibited at the highest BAPN dosage after much of the decrease in mature crosslinking density has been observed and when the further decrease in mature crosslinking density proceeds very slowly with increased drug dosage. These observations suggest that osteolathyrism does not become manifest until practically all mature crosslinking that can be affected has been inhibited. The mineralization process apparently can be maintained in the newly laid collagen even in the presence of severe osteolathyritic conditions. Intermolecular crosslinking in bone collagen appears to play an important role in the development of bone properties whether by direct or indirect processes. Much of the effects on bone properties occur at the higher BAPN dosages where overt osteolathyrism is observed and where there seem to be only small changes in crosslinking density.

Acetates↗
PubMed1991

[Partial purification and characterization of bone-resorbing factor from bovine bone matrix].

The mechanism of bone remodeling has been investigated by many researchers. However, little is known about the role of the local factors which exist in the bone matrix. In this study, the author attempted to purify the bone-resorbing factor from the bovine bone matrix and to find its role in bone remodeling. The demineralized bovine bone matrix was extracted with 4M Gdn-HCl and the bone-resorbing factor was purified by means of heparin affinity and gel filtration chromatography. The analysis of bone resorption was carried out by the measurement of the released 45Ca from the pre-labeled mouse calvariae. The results of this study were that the bone-resorbing factor in the bone matrix was suggested to be a heat-stable glycoprotein having a molecular size higher than 150,000, which stimulated osteoclastic bone resorption via a prostaglandin-mediated mechanism.

Animals↗
PubMed1979

Detection of collagen degradation products from subcutaneously implanted organic bone matrix.

Demineralized bovine bone powder was reduced with NaB3H4 to label the collagen crosslinks with tritium. The powder was enclosed in small nylon mesh pouches and implanted subcutaneously into rats for 3 weeks. Histological examinations revealed that multinuclear giant cells accumulated around the bone matrix, some in Howship's lacunae. Collagenous peptides containing intermolecular crosslinks were detected in the urea-soluble fraction extracted from the implant. Two crosslink-containing peptides were isolated from a dialyzable fraction: one contained dihydroxylysinonorleucine and the other hydroxylysinonorleucine. Both peptides had molecular weights of approximately 1000 estimated from the elution positions of gel filtration chromatography; and both had similar quantitative compositions of amino acids. There were no homologous peptides detected in a control experiment of the reduced bone matrix which was incubated in vitro with buffered saline for 1 week at 37 degrees C.

Animals↗
PubMed1992

Factors influencing synthesis and mineralization of bone matrix from fetal bovine bone cells grown in vitro.

This study of the in vitro synthesis and mineralization of bovine bone demonstrates that sheets of mineralized matrix can be produced consistently within 18-24 days of cell isolation. Mineralization surpasses that achieved by other systems with other species: The deposition of mineral extends beyond nodules to form branching trabeculae and then solid wafers of bone. Comparison of the fetal age of the bone source, enzyme digestion methods, seeding density, culture surface, nutritive media, and concentration of fetal calf serum and other additives, including insulin and ascorbic acid, has yielded a set of optimal culture conditions. In the presence of ascorbic acid and beta-glycerol phosphate, insulin has a dose-dependent effect on the morphology of the mineralized bone matrix produced. Quantitative analysis shows that in these cultures calcium accumulates most rapidly between days 6 and 10 after the introduction of mineralization medium but that mineral accretion continues throughout 14-16 days of culture. Alkaline phosphatase levels rise up to 200-fold, concomitant with a rapid increase in the number of cells per culture during the early mineralization phases; both fall as mineralization proceeds. This system has been used to study the induction of mRNA of type I collagen, alkaline phosphatase, and several noncollagenous bone proteins during the course of mineralization. Because of the degree of mineralization achieved with this system, it has many potential applications.

Alkaline Phosphatase↗
PubMed1986

Pulverized bone matrix as an injectable bone graft in rabbit radius defects.

A segment of the rabbit radius diaphysis was excised, demineralized, and pulverized. The demineralized matrix particles were mixed with autologous bone marrow from the femoral canal and injected into the defect from which it had been excised. On the contralateral side, the demineralized bone was reimplanted without pulverization, but with bone marrow. The bone yield was measured by radiographic planimetry and Tc99m MDP scintimetry. The forearms of the rabbits were sectioned into transverse segments, including the middle of the radius defect. The ash weights and the Ca45 content of these segments were measured. After two weeks, the ash weight was greater on the pulverized than on the unpulverized side; but by four weeks, measurements showed no difference. In general, the injectable bone matrix preparation did not interfere with bone repair. In comparing the Tc99m and Ca45 methods, the latter provided high-precision data with respect to the biologic variation.

Animals↗
PubMed1991

Effect of diet on bone matrix constituents.

Bone formation occurs in an integrated, highly ordered manner, beginning in the embryonic period. Nutrients may affect bone formation by delaying cellular differentiation, altering responses to bone growth factors, affecting supply of needed nutrients, and/or affecting rates of synthesis of the matrix constituents. Several growth factors, both systemic and local, are being identified which affect bone formation. Matrix constituents include collagen and noncollagenous proteins, each of which are thought to have specific roles in bone formation, maintenance, or resorption. Among the nutrients which are known to affect bone formation at a cellular level are vitamins A, D, and K, ascorbic acid, zinc, magnesium, and calcium. Nutrients that are known to affect protein synthesis in general also affect bone formation. It is necessary for nutritionists to consider cellular as well as systemic effects of nutrients on bone formation.

Bone Development↗
PubMed1992

Ultrastructural observation of calcification preceding new bone formation induced by demineralized bone matrix gelatin.

Demineralized bone matrix gelatin (BMG) was implanted into the skeletal muscle of Sprague-Dawley rats, and the resulting ultrastructural changes of the BMG were examined 3, 5, 7, 10, 15 and 20 days later. Most of the implanted BMG became calcified 7-20 days after implantation. Calcification ('acellular mineral deposition') was first observed as needle-shaped crystalline deposits in the BMG matrix on day 7 after implantation, which gradually increased in size and fused with one another in some deposits. They appeared to be divided into small partitions consisting of denatured collagen fibers unlike those of noncalcified BMG. Some deposits had electron-lucent areas in their center adjacent to well-calcified peripheral areas, and the central area contained many collagen-like fibers and spherical vacuoles. Osteoblast-like cells were not present around these calcified deposits 7 days after implantation. After that, new bone formation was often seen near the area of acellular mineral deposition, and the fused calcified deposits remained until day 15 after implantation. The noncalcified BMG was mainly absorbed by macrophages, and the sites of acellular mineral deposition were absorbed by multinucleated cells resembling osteoclasts which were considered to be activated by the implants. Acellular mineral deposition probably started as calcium and phosphate deposits on some materials in the BMG matrix, and by heterogenic nucleation without osteoblasts or matrix vesicles, inducing bone formation. Thus the BMG may be not only a carrier of bone morphogenetic protein, gradually supplying it to the surrounding tissue but also a storage site for minerals that are indispensable for bone formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1986

Effect of acute increases in bone matrix degradation on circulating levels of bone-Gla protein.

Serum bone Gla-protein (BGP), also called osteocalcin, is a specific and sensitive measure of bone turnover in a variety of metabolic bone disorders. Although some BGP diffuses into the circulation after synthesis by osteoblasts, most is incorporated into bone matrix where it remains until bone is resorbed. Thus, serum BGP could reflect bone formation, bone resorption, or a combination of both. The relationship of serum BGP to the components of bone turnover was evaluated in 18 normal women (mean age 48 yr; range 30-70) who received a continuous 24-h intravenous infusion of the 1-34 synthetic fragment of bovine parathyroid hormone. Mean +/- SE for urinary hydroxyproline excretion, an index of bone resorption, increased (from 22.7 +/- 2.2 to 38.5 +/- 3.7 micrograms/100 ml glomerular filtrate [GF], p less than .001), whereas levels of serum alkaline phosphatase, an index of bone formation, were unchanged (from 20 +/- 1 to 20 +/- 1 U/liter, NS). Despite the increase in bone resorption, levels of serum BGP decreased (from 8.8 +/- 0.8 to 6.8 ng/dl, p less than .001). The data suggest that circulating levels of BGP are a measure of bone formation but, at least in subjects with normal renal function, not a measure of bone resorption. Presumably BGP in bone matrix is degraded during osteoclastic resorption into fragments that either are not recognized by an antiserum raised against the native molecule or are rapidly cleared from the circulation.

Adult↗
PubMed1992

In situ hybridization of bone matrix proteins in undecalcified adult rat bone sections.

We have developed a method for in situ hybridization of adult bone tissue utilizing undecalcified sections and have used it to histologically examine the mRNA expression of non-collagenous bone matrix proteins such as osteocalcin (bone Gla protein, BGP), matrix Gla protein (MGP), and osteopontin in adult rats. Expression was compared with that in bone tissues of newborn rats. In the adult bone tissue, osteocalcin mRNA was strongly expressed in periosteal and endosteal cuboidal osteoblasts but not in primary spongiosa near the growth plate. Osteopontin mRNA was strongly expressed in cells present on the bone resorption surface, osteocytes, and hypertrophic chondrocytes, but not in cuboidal osteoblasts on the formation surface. Osteopontin and osteocalcin mRNAs were expressed independently and the distribution of cells expressing osteopontin mRNA corresponded with acid phosphatase-positive mononuclear cells and osteoclasts. Expression of MGP mRNA was noted only in hypertrophic chondrocytes. In newborn rat bone tissues, expression of osteocalcin mRNA was much weaker than in adult rat bone tissues. These results clearly indicate the differential expression of mRNAs of non-collagenous bone matrix proteins in adult rat bone tissues.

Animals↗