bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vivo RANK Signaling Blockade Using the Receptor Activator of NF-κB:Fc Effectively Prevents and Ameliorates Wear Debris-Induced Osteolysis via Osteoclast Depletion Without Inhibiting Osteogenesis
Authors: Childs Lisa M. , Paschalis Eleftherios P. , Xing Lianping , Dougall William C. , Anderson Dirk , Boskey Adele L. , Puzas J. Edward , Rosier Randy N. , O'Keefe Regis J. , Boyce Brendan F. , Schwarz Edward M. 
Published: April 2006

Abstract
Prosthesis failure due to wear debris-induced osteolysis remains a major clinical problem and the greatest limitation for total joint arthroplasty. Based on our knowledge of osteoclast involvement in this process and the requirements of receptor activator of NF-κB (RANK) signaling in osteoclastogenesis and bone resorption, we investigated the efficacy of RANK blockade in preventing and ameliorating titanium (Ti)-induced osteolysis in a mouse calvaria model. Compared with placebo controls we found that all doses of RANK:Fc above 1 mg/kg intraperitoneally (ip) per 48 h significantly inhibited osteoclastogenesis and bone resorption in response to Ti implanted locally. Complete inhibition occurred at 10 mg/kg ip per 48 h, yielding results that were statistically equivalent to data obtained with Ti-treated RANK−/− mice. We also evaluated the effects of a single injection of RANK:Fc on day 5 on established osteolysis and found that Ti-treated were still depleted for multinucleated tartrate-resistant acid phosphatase-positive (TRAP+) cells 16 days later. More importantly, this osteoclast depletion did not affect bone formation because the bone lost from the osteolysis on day 5 was restored by day 21. An assessment of the quantity and quality of the newly formed bone in these calvariae by calcein labeling and infrared (IR) microscopy, respectively, showed no significant negative effect of RANK:Fc treatment. These studies indicate that osteoclast depletion via RANK blockade is an effective method to prevent and reverse wear debris-induced osteolysis without jeopardizing osteogenesis.
Periodontal Ligament Cells Under Mechanical Stress Induce Osteoclastogenesis by Receptor Activator of Nuclear Factor κB Ligand Up-Regulation via Prostaglandin E2 Synthesis
Authors: Kanzaki Hiroyuki , Chiba Mirei , Shimizu Yoshinobu , Mitani Hideo 
Published: April 2006

Abstract
Previously, we discovered that periodontal ligament (PDL) cells not only support osteoclastogenesis through cell-to-cell contact, but also inhibit the formation of tartrate-resistant acid phosphatase-positive (TRAP+) multinucleated cells by a producing soluble factor(s). Furthermore, PDL cells express both receptor activator of nuclear factor κB ligand (RANKL) and osteoprotegerin (OPG) messenger RNA (mRNA). Clinically, “ankylosed teeth,” which lack periodontal ligament, cannot be moved with orthodontic tooth treatment. From this, we hypothesized that PDL cells under mechanical stress should play a pivotal role in osteoclast formation during orthodontic tooth movement. This study examined how mechanical stress affects the osteoclastogenesis-supporting activity of PDL cells. PDL cells were compressed continuously and then cocultured with peripheral blood mononuclear cells (PBMCs) for 4 weeks. PDL cells under mechanical stress up-regulated osteoclastogenesis from PBMCs. Furthermore, the expression of RANKL mRNA and protein in PDL cells increased with compressive force in parallel with the change in the number of osteoclasts. In addition, cyclo-oxygenase 2 (COX-2) mRNA expression was induced by compressive force, and indomethacin inhibited the RANKL up-regulation resulting from compressive force. PDL cells under compressive force exhibited significantly increased prostaglandin E2 (PGE2) production in comparison with control PDL cells. Exogenous PGE2 treatment increased RANKL mRNA expression in PDL cells. Interestingly, OPG expression remained constant throughout compressive force or PGE2 treatment. In conclusion, compressive force up-regulated RANKL expression in PDL cells. Furthermore, RANKL up-regulation in mechanically stressed PDL cells was dependent on PGE2.
Recombinant Human Bone Morphogenetic Protein-2 Enhances Osteotomy Healing in Glucocorticoid-Treated Rabbits
Authors: Luppen C. A. , Blake C. A. , Ammirati K. M. , Stevens M. L. , Seeherman H. J. , Wozney J. M. , Bouxsein M. L. 
Published: April 2006

Abstract
The objectives of this study were to evaluate the effect of chronic prednisolone treatment on osteotomy healing in rabbits and to determine whether recombinant human bone morphogenetic protein-2 (rhBMP-2) would enhance healing in the presence of chronic glucocorticoid therapy. Forty-nine skeletally mature, male rabbits were injected with either prednisolone (n = 26; 0.35 mg/kg per day, three times a week) or saline (n = 23). After a 6-week pretreatment period, bilateral ulnar osteotomies were created surgically. One osteotomy was treated with rhBMP-2 (0.2 mg/ml of rhBMP-2, 40 μg of rhBMP-2 total) delivered on an absorbable collage sponge (ACS), whereas the contralateral osteotomy remained untreated. Prednisolone or saline treatment was continued until the rabbits were killed either 6 weeks or 8 weeks after creation of the osteotomy. Osteotomy healing was evaluated by radiography, peripheral quantitative computed tomography (pQCT), torsional biomechanics, and undecalcified histology. Because we observed similar responses to both prednisolone and rhBMP-2/ACS treatment in the 6-week and 8-week cohorts, the results from these time points were combined. Serum osteocalcin and vertebral trabecular bone density were lower in the prednisolone-treated rabbits. Prednisolone treatment dramatically inhibited osteotomy healing. In the untreated ulnas, callus area and torsional strength were 25% and 55% less, respectively, in the prednisolone-treated rabbits than in the saline group (p &lt; 0.001 for both). rhBMP-2/ACS enhanced healing in both the prednisolone- and the saline-treated groups, although the effect was larger in the prednisolone-treated rabbits. In the prednisolone-treated rabbits, callus area and torsional strength were 40% and 165% greater (p &lt; 0.001 for both), respectively, in osteotomies treated with rhBMP-2/ACS compared with the contralateral, untreated osteotomies. Histological evaluation confirmed that osteotomy healing was inhibited by prednisolone and accelerated by rhBMP-2/ACS. In summary, a single application of rhBMP-2/ACS counteracted the inhibition of osteotomy healing caused by prednisolone exposure. These results suggest that rhBMP-2/ACS may be a useful treatment for enhancing fracture healing in patients who are undergoing chronic glucocorticoid therapy.
Ontogeny of Phex/PHEX Protein Expression in Mouse Embryo and Subcellular Localization in Osteoblasts
Authors: Thompson D. L. , Sabbagh Y. , Tenenhouse H. S. , Roche P. C. , Drezner M. K. , Salisbury J. L. , Grande J. P. , Poeschla E. M. , Kumar R. 
Published: April 2006

Abstract
PHEX, a phosphate-regulating gene with homologies to endopeptidases on the X chromosome, is mutated in X-linked hypophosphatemia (XLH) in humans and mice (Hyp). Although recent observations indicate that Phex protein is expressed primarily in bone and may play an important role in osteoblast function and bone mineralization, the pattern of the Phex protein expression in the developing skeleton and its subcellular localization in osteoblasts remain unknown. We examined the ontogeny of the Phex protein in the developing mouse embryo and its subcellular localization in osteoblasts using a specific antibody to the protein. Immunohistochemical staining of mouse embryos revealed expression of Phex in osteogenic precursors in developing vertebral bodies and developing long bones on day 16 postcoitum (pc) and thereafter. Calvaria from day 18 pc mice showed Phex epitopes in osteoblasts. No Phex immunoreactivity was detected in lung, heart, hepatocytes, kidney, intestine, skeletal muscle, or adipose tissue of mouse embryos. Interestingly, embryonic mouse skin showed moderate amounts of Phex immunostaining. In postnatal mice, Phex expression was observed in osteoblasts and osteocytes. Moderate expression of Phex was seen in odontoblasts and slight immunoreactivity was observed in ameloblasts. Confocal microscopy revealed the presence of immunoreactive PHEX protein in the Golgi apparatus and endoplasmic reticulum of osteoblasts from normal mice and in osteoblasts from Hyp mice transduced with a human PHEX viral expression vector. PHEX protein was not detected in untransduced Hyp osteoblasts. These data indicate that Phex protein is expressed in osteoblasts and osteocytes during the embryonic and postnatal periods and that within bone, Phex may be a unique marker for cells of the osteoblast/osteocyte lineage.
Overexpressed LIM Mineralization Proteins Do Not Require LIM Domains to Induce Bone
Authors: Liu Yunshan , Hair Gregory A. , Boden Scott D. , Viggeswarapu Manjula , Titus Louisa 
Published: April 2006

Abstract
Rat LIM mineralization protein 1 (LMP-1, an LIM domain protein) mediates bone morphogenetic protein 6 (BMP-6) induction of bone nodule formation in fetal rat calvarial osteoblast (ROB) cultures. We have isolated the complementary DNA (cDNA) for the human homologue of LMP-1 from an adult human heart cDNA library and showed that when overexpressed it is osteoinductive in the same culture system. The recently revised cDNA sequence of Enigma, the protein product of which binds to the insulin receptor and the tyrosine kinase receptor ret, now matches the nucleotide sequence of human LMP-1 (hLMP-1). A truncated, 223 amino acid (AA) LMP-1(t) protein has identical effects as the full-length protein, despite the deletion of the LIM domains. Two splice variants of human LMP-1 have been detected. Human LMP-2 has a 119-base pair (bp) deletion between bp 325 and 444 and a 17-bp insertion at bp 444. The resulting derived protein contains 423 AA with the LIM domains intact and does not induce bone formation when overexpressed in ROB cultures. Human LMP-3 has the same 17 nucleotide insertion at bp 444, resulting in a shift in the reading frame that causes a stop codon to occur at bp 505-507. The resulting 153 AA protein does not have the LIM domains, but overexpression of hLMP-3 induces bone formation in osteoblast cultures. These findings suggest that the LIM domains are not required for LMPs to induce bone formation. In addition, a small region (36 AA) of the LMP-1 protein may be required for bone formation.
Differential Temporal Expression of Members of the Transforming Growth Factor β Superfamily During Murine Fracture Healing
Authors: Cho Tae-Joon , Gerstenfeld Louis C. , Einhorn Thomas A. 
Published: April 2006

AbstractFracture healing is a unique postnatal repair process in which the events of endochondral and intramembranous bone formation follow a definable temporal sequence. The temporal patterns of messenger RNA (mRNA) expression for members of the transforming growth factor β (TGF-β) superfamily were examined over a 28-day period of fracture healing in mouse tibias. Bone morphogenetic protein 2 (BMP-2) and growth and differentiation factor 8 (GDF8) showed maximal expression on day 1 after fracture, suggesting their roles as early response genes in the cascade of healing events. Restricted expression of GDF8 to day 1, in light of its known actions as a negative regulator of skeletal muscle growth, suggests that it may similarly regulate cell differentiation early in the fracture healing process. GDF5, TGF-β2, and TGF-β3 showed maximal expression on day 7, when type II collagen expression peaked during cartilage formation. In contrast, BMP-3, BMP-4, BMP-7, and BMP-8 showed a restricted period of expression from day 14 through day 21, when the resorption of calcified cartilage and osteoblastic recruitment were most active. TGF-β1, BMP-5 and BMP-6, and GDF10 were constitutively expressed from day 3 to day 21. However, during the same time period, GDF3, GDF6, and GDF9 could not be detected, and GDF1 was expressed at extremely low levels. These findings suggest that several members of the TGF-β superfamily are actively involved in fracture healing and although they are closely related both structurally and functionally, each has a distinct temporal expression pattern and potentially unique role in fracture healing.
Down-Regulation of Osteoclast Differentiation by Daidzein via Caspase 3
Authors: Rassi Claudia Maria , Lieberherr Michele , Chaumaz Gilles , Pointillart Alain , Cournot Giulia 
Published: April 2006

Abstract
Phytoestrogens are plant-derived compounds with estrogen-like activity. Phytoestrogen-rich diets may prevent postmenopausal osteoporosis and these molecules maintain bone mass in ovariectomized animals. We compared the effects of the isoflavone daidzein, which has no action on tyrosine kinases, and 17β-estradiol on the development and activity of osteoclasts in vitro. Nonadherent porcine bone marrow cells were cultured on dentine slices or on culture slides in the presence of 10−8 M of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], with or without 10−8 M of daidzein, 10−8 M of 17β-estradiol for 9-11 days. Multinucleated tartrate-resistant acid phosphatase-positive (TRAP+) cells that resorbed bone (osteoclasts) developed in the presence of 1,25(OH)2D3. The number of osteoclasts formed in response to 1,25(OH)2D3 was reduced by 58 ± 8% by daidzein and 52 ± 5% by estrogen (p &lt; 0.01); these effects were reversed by 10−6 M of ICI 182,780. The area resorbed by mature osteoclasts was reduced by 39 ± 5% by daidzein and 42 ± 6% by estradiol (p &lt; 0.01). Both compounds also inhibited the 1,25(OH)2D3-induced differentiation of osteoclast progenitors (mononucleated TRAP+ cells), 53 ± 8% by daidzein and 50 ± 7% by estradiol (p &lt; 0.05). Moreover, daidzein and estradiol promoted caspase-8 and caspase-3 cleavage and DNA fragmentation of monocytic bone marrow cells. Caspase-3 cleavage was reversed by 10−8 M of ICI 182,780. Both compounds up-regulated the expression of nuclear estrogen receptors ER-α and ER-β. Thus, daidzein, at the same concentration as 17β-estradiol, inhibits osteoclast differentiation and activity. This may be caused by, at least in part, greater apoptosis of osteoclast progenitors mediated by ERs.
Incidence of Vertebral Fracture in Europe: Results From the European Prospective Osteoporosis Study (EPOS)
Authors:   Dr. D AJ M G AA JD WC D LI A Armas JB C J R B W S K I J O JA G Vaz A R G P C T G Hap G HH DM W Nave JJ CJ K AD OB J Terence W. Felsenberg Silman Lunt Armbrecht Ismail Finn Cockerill Banzer Benevolenskaya Bhalla Bruges Cannata Cooper Dequeker Eastell Felsch Gowin Havelka Hoszowski Jajic Janott Johnell Kanis Kragl Lopes Lorenc Lyritis Masaryk Matthis Miazgowski Parisi Pols Poor Raspe Reid Reisinger Scheidt Stepan Todd Weber Woolf Yershova Reeve O'Neill
Published: April 2006

Abstract
Vertebral fracture is one of the major adverse clinical consequences of osteoporosis; however, there are few data concerning the incidence of vertebral fracture in population samples of men and women. The aim of this study was to determine the incidence of vertebral fracture in European men and women. A total of 14,011 men and women aged 50 years and over were recruited from population-based registers in 29 European centers and had an interviewer-administered questionnaire and lateral spinal radiographs performed. The response rate for participation in the study was approximately 50%. Repeat spinal radiographs were performed a mean of 3.8 years following the baseline film. All films were evaluated morphometrically. The definition of a morphometric fracture was a vertebra in which there was evidence of a 20% (+4 mm) or more reduction in anterior, middle, or posterior vertebral height between films—plus the additional requirement that a vertebra satisfy criteria for a prevalent deformity (using the McCloskey-Kanis method) in the follow-up film. There were 3174 men, mean age 63.1 years, and 3614 women, mean age 62.2 years, with paired duplicate spinal radiographs (48% of those originally recruited to the baseline survey). The age standardized incidence of morphometric fracture was 10.7/1000 person years (pyr) in women and 5.7/1000 pyr in men. The age-standardized incidence of vertebral fracture as assessed qualitatively by the radiologist was broadly similar—12.1/1000 pyr and 6.8/1000 pyr, respectively. The incidence increased markedly with age in both men and women. There was some evidence of geographic variation in fracture occurrence; rates were higher in Sweden than elsewhere in Europe. This is the first large population-based study to ascertain the incidence of vertebral fracture in men and women over 50 years of age across Europe. The data confirm the frequent occurrence of the disorder in men as well as in women and the rise in incidence with age.
Why Is the Age-Standardized Incidence of Low-Trauma Fractures Rising in Many Elderly Populations?
Authors: Kannus Pekka , Niemi Seppo , Parkkari Jari , Palvanen Mika , Heinonen Ari , Sievänen Harri , Järvinen Teppo , Khan Karim , Järvinen Markku 
Published: April 2006

Abstract
Low-trauma fractures of elderly people are a major public health burden worldwide, and as the number and mean age of older adults in the population continue to increase, the number of fractures is also likely to increase. Epidemiologically, however, an additional concern is that, for unknown reasons, the age-standardized incidence (average individual risk) of fracture has also risen in many populations during the recent decades. Possible reasons for this rise include a birth cohort effect, deterioration in the average bone strength by time, and increased average risk of (serious) falls. Literature provides evidence that the rise is not due to a birth cohort effect, whereas no study shows whether bone fragility has increased during this relatively short period of time. This osteoporosis hypothesis could, however, be tested if researchers would now repeat the population measurements of bone mass and density that were made in the late 1980s and the 1990s. If such studies proved that women's and men's age-standardized mean values of bone mass and density have declined over time, the osteoporosis hypothesis would receive scientific support. The third explanation is based on the hypothesis that the number and/or severity of falls has risen in elderly populations during the recent decades. Although no study has directly tested this hypothesis, a great deal of indirect epidemiologic evidence supports this contention. For example, the age-standardized incidence of fall-induced severe head injuries, bruises and contusions, and joint distortions and dislocations has increased among elderly people similarly to the low-trauma fractures. The fall hypothesis could also be tested in the coming years because the 1990s saw many research teams reporting age- and sex-specific incidences of falling for elderly populations, and the same could be done now to provide data comparing the current incidence rates of falls with the earlier ones.
Kinetic Characterization of Hypophosphatasia Mutations With Physiological Substrates
Authors: Di Mauro Sonia , Manes Thomas , Hessle Lovisa , Kozlenkov Alexey , Pizauro João Martins , Hoylaerts Marc F. , Millán José Luis 
Published: April 2006

Abstract
We have analyzed 16 missense mutations of the tissue-nonspecific AP (TNAP) gene found in patients with hypophosphatasia. These mutations span the phenotypic spectrum of the disease, from the lethal perinatal/infantile forms to the less severe adult and odontohypophosphatasia. Site-directed mutagenesis was used to introduce a sequence tag into the TNAP cDNA and eliminate the glycosylphosphatidylinositol (GPI)-anchor recognition sequence to produce a secreted epitope-tagged TNAP (setTNAP). The properties of GPI-anchored TNAP (gpiTNAP) and setTNAP were found comparable. After introducing each single hypophosphatasia mutation, the setTNAP and mutant TNAP cDNAs were expressed in COS-1 cells and the recombinant flagged enzymes were affinity purified. We characterized the kinetic behavior, inhibition, and heat stability properties of each mutant using the artificial substrate p-nitrophenylphosphate (pNPP) at pH 9.8. We also determined the ability of the mutants to metabolize two natural substrates of TNAP, that is, pyridoxal-5′-phosphate (PLP) and inorganic pyrophosphate (PPi), at physiological pH. Six of the mutant enzymes were completely devoid of catalytic activity (R54C, R54P, A94T, R206W, G317D, and V365I), and 10 others (A16V, A115V, A160T, A162T, E174K, E174G, D277A, E281K, D361V, and G439R) showed various levels of residual activity. The A160T substitution was found to decrease the catalytic efficiency of the mutant enzyme toward pNPP to retain normal activity toward PPi and to display increased activity toward PLP. The A162T substitution caused a considerable reduction in the pNPPase, PPiase, and PLPase activities of the mutant enzyme. The D277A mutant was found to maintain high catalytic efficiency toward pNPP as substrate but not against PLP or PPi. Three mutations (E174G, E174K, and E281K) were found to retain normal or slightly subnormal catalytic efficiency toward pNPP and PPi but not against PLP. Because abnormalities in PLP metabolism have been shown to cause epileptic seizures in mice null for the TNAP gene, these kinetic data help explain the variable expressivity of epileptic seizures in hypophosphatasia patients.
Differential Expression of Estrogen Receptor-Related Receptor α and Estrogen Receptors α and β in Osteoblasts In Vivo and In Vitro
Authors: Bonnelye Edith , Aubin Jane E. 
Published: April 2006

Abstract
The orphan nuclear estrogen receptor-related receptor (ERR) α is expressed by osteoblastic cells, is known to transactivate at least one osteoblast-associated gene osteopontin (OPN) and plays a functional role in osteoprogenitor cell proliferation and differentiation. To dissect further the role of ERR-α in bone formation, we compared its expression to that of the estrogen receptor (ER) α and ER-β in rat calvaria (RC) and fetal tibia in vivo and in RC and rat bone marrow (RBM) cells in vitro. We found that ERR-α is highly and widely expressed in most, if not all, cells in RC cell cultures from early proliferation stages through mineralized nodule formation; ER-α was localized similarly but at lower levels and ER-β, although present, was barely detectable. These patterns of expression in vitro correlated with what we observed in vivo in sections of 21-day fetal RC, in which ERR-α appeared to be more highly expressed than either of the ERs. Interestingly, ERR-α also is highly expressed in RBM cells, while ER-α and ER-β mRNA is expressed, but at lower levels. Moreover, we found that ERR-α, ER-α, and ER-β were all expressed in osteoblasts in fetal and adult tibia whereas they were expressed differentially in calvaria in vivo in subsets of osteoblasts, supporting the hypothesis that ERR-α may interact with one or both of the ERs in those osteoblasts in which they are coexpressed and that all three receptors may be required for bone formation but at different times and for different functions.