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Blair HC, Larrouture QC, Tourkova IL, Nelson DJ, Dobrowolski SF, Schlesinger PH. Epithelial-like transport of mineral distinguishes bone formation from other connective tissues. J Cell Biochem 2023; 124:1889-1899. [PMID: 37991446 PMCID: PMC10880123 DOI: 10.1002/jcb.30494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/10/2023] [Accepted: 10/24/2023] [Indexed: 11/23/2023]
Abstract
We review unique properties of bone formation including current understanding of mechanisms of bone mineral transport. We focus on formation only; mechanism of bone degradation is a separate topic not considered. Bone matrix is compared to other connective tissues composed mainly of the same proteins, but without the specialized mechanism for continuous transport and deposition of mineral. Indeed other connective tissues add mechanisms to prevent mineral formation. We start with the epithelial-like surfaces that mediate transport of phosphate to be incorporated into hydroxyapatite in bone, or in its ancestral tissue, the tooth. These include several phosphate producing or phosphate transport-related proteins with special expression in large quantities in bone, particularly in the bone-surface osteoblasts. In all connective tissues including bone, the proteins that constitute the protein matrix are mainly type I collagen and γ-carboxylate-containing small proteins in similar molar quantities to collagen. Specialized proteins that regulate connective tissue structure and formation are surprisingly similar in mineralized and non-mineralized tissues. While serum calcium and phosphate are adequate to precipitate mineral, specialized mechanisms normally prevent mineral formation except in bone, where continuous transport and deposition of mineral occurs.
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Affiliation(s)
- Harry C Blair
- Veteran’s Affairs Medical Center, Pittsburgh PA
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA
| | | | - Irina L. Tourkova
- Veteran’s Affairs Medical Center, Pittsburgh PA
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA
| | - Deborah J Nelson
- Dept of Neurobiology, Pharmacology & Physiology, University of Chicago, Chicago IL
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2
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Tourkova IL, Larrouture QC, Onwuka KM, Liu S, Luo J, Schlesinger PH, Blair HC. Age-related decline in bone mineral transport and bone matrix proteins in osteoblasts from stromal stem cells. Am J Physiol Cell Physiol 2023; 325:C613-C622. [PMID: 37519232 PMCID: PMC10635645 DOI: 10.1152/ajpcell.00227.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/20/2023] [Accepted: 07/20/2023] [Indexed: 08/01/2023]
Abstract
We studied osteoblast bone mineral transport and matrix proteins as a function of age. In isolated bone marrow cells from long bones of young (3 or 4 mo) and old (18 or 19 mo) mice, age correlated with reduced mRNA of mineral transport proteins: alkaline phosphatase (ALP), ankylosis (ANK), the Cl-/H+ exchanger ClC3, and matrix proteins collagen 1 (Col1) and osteocalcin (BGLAP). Some proteins, including the neutral phosphate transporter2 (NPT2), were not reduced. These are predominately osteoblast proteins, but in mixed cell populations. Remarkably, in osteoblasts differentiated from preparations of stromal stem cells (SSCs) made from bone marrow cells in young and old mice, differentiated in vitro on perforated polyethylene terephthalate membranes, mRNA confirmed decreased expression with age for most transport-related and bone matrix proteins. Additional mRNAs in osteoblasts in vitro included ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), unchanged, and ENPP2, reduced with age. Decrease with age in ALP activity and protein by Western blot was also significant. Transport protein findings correlated with micro-computed tomography of lumbar vertebra, showing that trabecular bone of old mice is osteopenic relative to young mice, consistent with other studies. Pathway analysis of osteoblasts differentiated in vitro showed that cells from old animals had reduced Erk1/2 phosphorylation and decreased suppressor of mothers against decapentaplegic 2 (Smad2) mRNA, consistent with TGFβ pathway, and reduced β-catenin mRNA, consistent with WNT pathway regulation. Our results show that decline in bone density with age reflects selective changes, resulting effectively in a phenotype modification. Reduction of matrix and mineral transport protein expression with age is regulated by multiple signaling pathways.NEW & NOTEWORTHY This work for the first time showed that specific enzymes in bone mineral transport, and matrix synthesis proteins, in the epithelial-like bone-forming cell layer are downregulated with aging. Results were compared using cells extracted from long bones of young and old mice, or in essentially uniform osteoblasts differentiated from stromal stem cells in vitro. The age effect showed memory in the stromal stem cells, a remarkable finding.
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Affiliation(s)
- Irina L Tourkova
- Research Service, VA Medical Center, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Quitterie C Larrouture
- Research Service, VA Medical Center, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Kelechi M Onwuka
- Research Service, VA Medical Center, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Silvia Liu
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Jianhua Luo
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Paul H Schlesinger
- Department of Cell Biology & Physiology, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Harry C Blair
- Research Service, VA Medical Center, Pittsburgh, Pennsylvania, United States
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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3
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Brent MB. Pharmaceutical treatment of bone loss: From animal models and drug development to future treatment strategies. Pharmacol Ther 2023; 244:108383. [PMID: 36933702 DOI: 10.1016/j.pharmthera.2023.108383] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 02/18/2023] [Accepted: 03/09/2023] [Indexed: 03/17/2023]
Abstract
Animal models are fundamental to advance our knowledge of the underlying pathophysiology of bone loss and to study pharmaceutical countermeasures against it. The animal model of post-menopausal osteoporosis from ovariectomy is the most widely used preclinical approach to study skeletal deterioration. However, several other animal models exist, each with unique characteristics such as bone loss from disuse, lactation, glucocorticoid excess, or exposure to hypobaric hypoxia. The present review aimed to provide a comprehensive overview of these animal models to emphasize the importance and significance of investigating bone loss and pharmaceutical countermeasures from perspectives other than post-menopausal osteoporosis only. Hence, the pathophysiology and underlying cellular mechanisms involved in the various types of bone loss are different, and this might influence which prevention and treatment strategies are the most effective. In addition, the review sought to map the current landscape of pharmaceutical countermeasures against osteoporosis with an emphasis on how drug development has changed from being driven by clinical observations and enhancement or repurposing of existing drugs to today's use of targeted anti-bodies that are the result of advanced insights into the underlying molecular mechanisms of bone formation and resorption. Moreover, new treatment combinations or repurposing opportunities of already approved drugs with a focus on dabigatran, parathyroid hormone and abaloparatide, growth hormone, inhibitors of the activin signaling pathway, acetazolamide, zoledronate, and romosozumab are discussed. Despite the considerable progress in drug development, there is still a clear need to improve treatment strategies and develop new pharmaceuticals against various types of osteoporosis. The review also highlights that new treatment indications should be explored using multiple animal models of bone loss in order to ensure a broad representation of different types of skeletal deterioration instead of mainly focusing on primary osteoporosis from post-menopausal estrogen deficiency.
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Affiliation(s)
- Mikkel Bo Brent
- Department of Biomedicine, Aarhus University, Denmark, Wilhelm Meyers Allé 3, 8000 Aarhus C, Denmark.
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Xie J, Rittel D, Shemtov-Yona K, Shah FA, Palmquist A. A stochastic micro to macro mechanical model for the evolution of bone-implant interface stiffness. Acta Biomater 2021; 131:415-423. [PMID: 34129958 DOI: 10.1016/j.actbio.2021.06.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 06/05/2021] [Accepted: 06/09/2021] [Indexed: 01/05/2023]
Abstract
Upon placement of an implant into living bone, an interface is formed through which various biochemical, biological, physical, and mechanical interactions take place. This interface evolves over time as the mechanical properties of peri-implant bone increase. Owing to the multifactorial nature of interfacial processes, it is challenging to devise a comprehensive model for predicting the mechanical behavior of the bone-implant interface. We propose a simple spatio-temporally evolving mechanical model - from an elementary unit cell comprising randomly oriented mineralized collagen fibrils having randomly assigned stiffness all the way up to a macroscopic bone-implant interface in a gap healing scenario. Each unit cell has an assigned Young's modulus value between 1.62 GPa and 25.73 GPa corresponding to minimum (i.e., 0) and maximum (i.e., 0.4) limits of mineral volume fraction, respectively, in the overlap region of the mineralized collagen fibril. Gap closure and subsequent stiffening are modeled to reflect the two main directions of peri-implant bone formation, i.e., contact osteogenesis and distance osteogenesis. The linear elastic stochastic finite element model reveals highly nonlinear temporal evolution of bone-implant interface stiffness, strongly dictated by the specific kinetics of contact osteogenesis and distance osteogenesis. The bone-implant interface possesses a small stiffness until gap closure, which subsequently evolves into a much higher stiffness, and this transition is reminiscent of a percolation transition whose threshold corresponds to gap closure. The model presented here, albeit preliminary, can be incorporated into future calculations of the bone-implant system where the interface is well-defined mechanically. STATEMENT OF SIGNIFICANCE: A simple, physically informed model for the mechanical characteristics of the bone-implant interface is still missing. Here, we start by extending the reported mechanical characteristics of a one cubic micrometre unit cell to a 250 µm long interface made of 1 µm thick layers. The stiffness of each cell (based on mineral content) is assigned randomly to mimic bone micro-heterogeneity. The numerical study of this interface representative structure allows for the simultaneous determination of the spatio-temporal evolution of the mechanical response at local (discrete element) and global (overall model) scales. The proposed model is the first of this kind that can easily be incorporated into realistic future models of bone-implant interaction with emphasis on implant stability and different loading conditions.
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Short-term glucocorticoid excess blunts abaloparatide-induced increase in femoral bone mass and strength in mice. Sci Rep 2021; 11:12258. [PMID: 34112892 PMCID: PMC8192916 DOI: 10.1038/s41598-021-91729-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/31/2021] [Indexed: 12/21/2022] Open
Abstract
Glucocorticoids (GCs), such as prednisolone, are widely used to treat inflammatory diseases. Continuously long-term or high dose treatment with GCs is one of the most common causes of secondary osteoporosis and is associated with sarcopenia and increased risk of debilitating osteoporotic fragility fractures. Abaloparatide (ABL) is a potent parathyroid hormone-related peptide analog, which can increase bone mineral density (aBMD), improve trabecular microarchitecture, and increase bone strength. The present study aimed to investigate whether GC excess blunts the osteoanabolic effect of ABL. Sixty 12–13-week-old female RjOrl:SWISS mice were allocated to the following groups: Baseline, Control, ABL, GC, and GC + ABL. ABL was administered as subcutaneous injections (100 μg/kg), while GC was delivered by subcutaneous implantation of a 60-days slow-release prednisolone-pellet (10 mg). The study lasted four weeks. GC induced a substantial reduction in muscle mass, trabecular mineral apposition rate (MAR) and bone formation rate (BFR/BS), and endocortical MAR compared with Control, but did not alter the trabecular microarchitecture or bone strength. In mice not receiving GC, ABL increased aBMD, bone mineral content (BMC), cortical and trabecular microarchitecture, mineralizing surface (MS/BS), MAR, BFR/BS, and bone strength compared with Control. However, when administered concomitantly with GC, the osteoanabolic effect of ABL on BMC, cortical morphology, and cortical bone strength was blunted. In conclusion, at cortical bone sites, the osteoanabolic effect of ABL is generally blunted by short-term GC excess.
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Schlesinger PH, Braddock DT, Larrouture QC, Ray EC, Riazanski V, Nelson DJ, Tourkova IL, Blair HC. Phylogeny and chemistry of biological mineral transport. Bone 2020; 141:115621. [PMID: 32858255 PMCID: PMC7771281 DOI: 10.1016/j.bone.2020.115621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/24/2020] [Accepted: 08/24/2020] [Indexed: 02/08/2023]
Abstract
Three physiologically mineralizing tissues - teeth, cartilage and bone - have critical common elements and important evolutionary relationships. Phylogenetically the most ancient densely mineralized tissue is teeth. In jawless fishes without skeletons, tooth formation included epithelial transport of phosphates, a process echoed later in bone physiology. Cartilage and mineralized cartilage are skeletal elements separate from bone, but with metabolic features common to bone. Cartilage mineralization is coordinated with high expression of tissue nonspecific alkaline phosphatase and PHOSPHO1 to harvest available phosphate esters and support mineralization of collagen secreted locally. Mineralization in true bone results from stochastic nucleation of hydroxyapatite crystals within the cross-linked collagen fibrils. Mineral accumulation in dense collagen is, at least in major part, mediated by amorphous aggregates - often called Posner clusters - of calcium and phosphate that are small enough to diffuse into collagen fibrils. Mineral accumulation in membrane vesicles is widely suggested, but does not correlate with a definitive stage of mineralization. Conversely mineral deposition at non-physiologic sites where calcium and phosphate are adequate has been shown to be regulated in large part by pyrophosphate. All of these elements are present in vertebrate bone metabolism. A key biological element of bone formation is an epithelial-like cellular organization which allows control of phosphate, calcium and pH during mineralization.
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Affiliation(s)
- Paul H Schlesinger
- Dept of Cell Biology, Washington University, Saint Louis, MO, United States of America
| | - Demetrios T Braddock
- Dept. of Pathology, Yale New Haven Hospital, 310 Cedar Street, New Haven, CT, United States of America
| | - Quitterie C Larrouture
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Botnar Research Centre, Windmill Road, Oxford OX3 7LD, UK
| | - Evan C Ray
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Vladimir Riazanski
- Dept of Neurobiology, Pharmacology & Physiology, University of Chicago, Chicago, IL, United States of America
| | - Deborah J Nelson
- Dept of Neurobiology, Pharmacology & Physiology, University of Chicago, Chicago, IL, United States of America
| | - Irina L Tourkova
- Veteran's Affairs Medical Center, Pittsburgh PA and Department of Pathology, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Harry C Blair
- Veteran's Affairs Medical Center, Pittsburgh PA and Department of Pathology, University of Pittsburgh, Pittsburgh, PA, United States of America.
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Harrison KD, Hiebert BD, Panahifar A, Andronowski JM, Ashique AM, King GA, Arnason T, Swekla KJ, Pivonka P, Cooper DM. Cortical Bone Porosity in Rabbit Models of Osteoporosis. J Bone Miner Res 2020; 35:2211-2228. [PMID: 32614975 PMCID: PMC7702175 DOI: 10.1002/jbmr.4124] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 06/17/2020] [Accepted: 06/21/2020] [Indexed: 12/20/2022]
Abstract
Cortical bone porosity is intimately linked with remodeling, is of growing clinical interest, and is increasingly accessible by imaging. Thus, the potential of animal models of osteoporosis (OP) to provide a platform for studying how porosity develops and responds to interventions is tremendous. To date, rabbit models of OP have largely focused on trabecular microarchitecture or bone density; some such as ovariectomy (OVX) have uncertain efficacy and cortical porosity has not been extensively reported. Our primary objective was to characterize tibial cortical porosity in rabbit-based models of OP, including OVX, glucocorticoids (GC), and OVX + GC relative to controls (SHAM). We sought to: (i) test the hypothesis that intracortical remodeling is elevated in these models; (ii) contrast cortical remodeling and porosity in these models with that induced by parathyroid hormone (1-34; PTH); and (iii) contrast trabecular morphology in the proximal tibia across all groups. Evidence that an increase in cortical porosity occurred in all groups was observed, although this was the least robust for GC. Histomorphometric measures supported the hypothesis that remodeling rate was elevated in all groups and also revealed evidence of uncoupling of bone resorption and formation in the GC and OVX + GC groups. For trabecular bone, a pattern of loss was observed for OVX, GC, and OVX + GC groups, whereas the opposite was observed for PTH. Change in trabecular number best explained these patterns. Taken together, the findings indicated rabbit models provide a viable and varied platform for the study of OP and associated changes in cortical remodeling and porosity. Intriguingly, the evidence revealed differing effects on the cortical and trabecular envelopes for the PTH model. © 2020 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR)..
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Affiliation(s)
- Kim D Harrison
- Department of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Beverly D Hiebert
- Department of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Arash Panahifar
- BioMedical Imaging and Therapy Beamline, Canadian Light Source, Saskatoon, Canada.,Department of Medical Imaging, College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | | | | | - Gavin A King
- Department of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Terra Arnason
- Department of Medicine, College of Medicine, University of Saskatchewan, Saskatoon, Canada
| | - Kurtis J Swekla
- Research Services and Ethics Office, Office of the Vice President of Research, University of Saskatchewan, Saskatoon, Canada
| | - Peter Pivonka
- School of Mechanical, Medical, and Process Engineering, Queensland University of Technology, Brisbane, Australia
| | - David Ml Cooper
- Department of Anatomy, Physiology, and Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Canada
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Cui D, Zhao D, Huang S. Structural characterization of a safflower polysaccharide and its promotion effect on steroid-induced osteonecrosis in vivo. Carbohydr Polym 2020; 233:115856. [PMID: 32059907 DOI: 10.1016/j.carbpol.2020.115856] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/23/2019] [Accepted: 01/09/2020] [Indexed: 01/24/2023]
Abstract
A water-soluble polysaccharide (SPAW) was purified from Safflower and it was identified to be (1→3)-linked β-d-Glucan. The therapeutic effect and underlying mechanism of SPAW on steroid-induced avascular necrosis of the femoral head (SANFH) in a rabbit model was performed here. The abnormal histopathologic changes and apoptosis of femoral head in model group were significantly reverted after SPAW (25, 100 and 200 mg/kg) administration for 60 days, as evidenced by the a decline of empty lacunae rate, the average bone marrow fat cell size and the proportion of apoptotic cells. Furthermore, administration of SPAW significantly decreased the Bax and caspase-3 protein expression, but increased the protein expression of Bcl-2 when compared these in model rabbits. Meanwhile, increased hydroxyproline (HOP) and decreased serum hexosamine (HOM) concentration in rabbit serum were turned to the opposite way. The present study suggested that SPAW may provide an alternative treatment for the treatment of SANFH.
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Affiliation(s)
- Daping Cui
- Department of Orthopaedics, Affiliated Zhongshan Hospital of Dalian University, No 6 Jiefang Street, Zhongshan District, Dalian 116001, China
| | - Dewei Zhao
- Department of Orthopaedics, Affiliated Zhongshan Hospital of Dalian University, No 6 Jiefang Street, Zhongshan District, Dalian 116001, China.
| | - Shibo Huang
- Department of Orthopaedics, Affiliated Zhongshan Hospital of Dalian University, No 6 Jiefang Street, Zhongshan District, Dalian 116001, China
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9
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Schlesinger PH, Blair HC, Beer Stolz D, Riazanski V, Ray EC, Tourkova IL, Nelson DJ. Cellular and extracellular matrix of bone, with principles of synthesis and dependency of mineral deposition on cell membrane transport. Am J Physiol Cell Physiol 2019; 318:C111-C124. [PMID: 31532718 DOI: 10.1152/ajpcell.00120.2019] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bone differs from other connective tissues; it is isolated by a layer of osteoblasts that are connected by tight and gap junctions. This allows bone to create dense lamellar type I collagen, control pH, mineral deposition, and regulate water content forming a compact and strong structure. New woven bone formed after degradation of mineralized cartilage is rapidly degraded and resynthesized to impart structural order for local bone strength. Ossification is regulated by thickness of bone units and by patterning via bone morphogenetic receptors including activin, other bone morphogenetic protein receptors, transforming growth factor-β receptors, all part of a receptor superfamily. This superfamily interacts with receptors for additional signals in bone differentiation. Important features of the osteoblast environment were established using recent tools including osteoblast differentiation in vitro. Osteoblasts deposit matrix protein, over 90% type I collagen, in lamellae with orientation alternating parallel or orthogonal to the main stress axis of the bone. Into this organic matrix, mineral is deposited as hydroxyapatite. Mineral matrix matures from amorphous to crystalline hydroxyapatite. This process includes at least two-phase changes of the calcium-phosphate mineral as well as intermediates involving tropocollagen fibrils to form the bone composite. Beginning with initiation of mineral deposition, there is uncertainty regarding cardinal processes, but the driving force is not merely exceeding the calcium-phosphate solubility product. It occurs behind a epithelial-like layer of osteoblasts, which generate phosphate and remove protons liberated during calcium-phosphate salt deposition. The forming bone matrix is discontinuous from the general extracellular fluid. Required adjustment of ionic concentrations and water removal from bone matrix are important details remaining to be addressed.
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Affiliation(s)
| | - Harry C Blair
- Veterans Affairs Medical Center, Pittsburgh, Pennsylvania.,Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Donna Beer Stolz
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Vladimir Riazanski
- Department of Neurobiology, Pharmacology, and Physiology, University of Chicago, Chicago, Illinois
| | - Evan C Ray
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Irina L Tourkova
- Veterans Affairs Medical Center, Pittsburgh, Pennsylvania.,Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Deborah J Nelson
- Department of Neurobiology, Pharmacology, and Physiology, University of Chicago, Chicago, Illinois
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Chandler H, Brooks DJ, Hattersley G, Bouxsein ML, Lanske B. Abaloparatide increases bone mineral density and bone strength in ovariectomized rabbits with glucocorticoid-induced osteopenia. Osteoporos Int 2019; 30:1607-1616. [PMID: 31053927 PMCID: PMC6663928 DOI: 10.1007/s00198-019-04999-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 04/21/2019] [Indexed: 12/22/2022]
Abstract
UNLABELLED Glucorticoid (GC) therapy is the commonest cause of secondary osteoporosis. Ovariectomized rabbits receiving the GC methylprednisolone for 6 weeks exhibited relatively lower vertebral and femoral bone mass. Treatment with the PTH receptor agonist abaloparatide for 12 weeks during ongoing methylprednisolone administration increased cortical and trabecular bone mass and femur bending strength. INTRODUCTION Abaloparatide, an osteoanabolic PTHrP analog, increases bone mineral density (BMD) and reduces fracture risk in women with postmenopausal osteoporosis. This study assessed abaloparatide effects on BMD and bone strength in ovariectomized (OVX) rabbits with glucocorticoid (GC)-induced osteopenia. METHODS Thirty-two rabbits underwent OVX and 8 underwent sham surgery. One day later, 24 OVX rabbits began daily s.c. GC injections (methylprednisolone, 1 mg/kg/day) for 6 weeks, while 8 OVX and 8 sham controls received no GC. GC-challenged rabbits (8/group) then received GC (0.5 mg/kg/day) along with daily s.c. vehicle (GC-OVX), abaloparatide 5 μg/kg/day (ABL5), or 25 μg/kg/day (ABL25) for 12 weeks, and the no-GC OVX and sham controls received daily vehicle. RESULTS GC-OVX rabbits showed significant deficits in vertebral and proximal femur areal BMD, lower cortical area, thickness and volumetric BMD of the femur diaphysis, and reduced trabecular bone volume and volumetric BMD in the vertebra and distal femur versus sham controls. These deficits were significantly reversed in the ABL25 group, which also showed enhanced trabecular micro-architecture versus GC-OVX controls. Destructive bending tests showed significantly lower femur diaphysis ultimate load and bending rigidity of the femoral diaphysis in the GC-OVX group versus sham controls, whereas these parameters were similar in the ABL25 group vs sham controls. CONCLUSIONS Abaloparatide 25 μg/kg/day mitigated the adverse effects of GC administration on cortical and trabecular bone and improved femoral strength in OVX rabbits. These results suggest potential promise for abaloparatide as an investigational therapy for glucocorticoid-induced osteoporosis.
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Affiliation(s)
- H Chandler
- Radius Health Inc., 950 Winter Street, Waltham, MA, 02451, USA
| | - D J Brooks
- Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - G Hattersley
- Radius Health Inc., 950 Winter Street, Waltham, MA, 02451, USA
| | - M L Bouxsein
- Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Department of Orthopedic Surgery, Harvard Medical School, Boston, MA, USA
| | - B Lanske
- Radius Health Inc., 950 Winter Street, Waltham, MA, 02451, USA.
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11
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Permuy M, López-Peña M, Muñoz F, González-Cantalapiedra A. Rabbit as model for osteoporosis research. J Bone Miner Metab 2019; 37:573-583. [PMID: 31087186 DOI: 10.1007/s00774-019-01007-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/20/2019] [Indexed: 10/26/2022]
Abstract
Osteoporosis is a major public health problem affecting more than 200 million people worldwide. The use of different animal models, for the study of its pathophysiology and treatments, is important being actually the ovariectomized rat the most widely used; although this model has several problems due its small size, lack of true closure of epiphyseal plate and bone differences with humans. This review is aimed at summarizing the most common methods published for osteoporosis induction in rabbits as model for human disease with their advantages and disadvantages. The paper shows the advantages of the use of this specie compared with the rat. All the techniques seemed to achieve the osteoporotic condition, but the one which obtained the most consistent bone mineral reduction in less time was the combination of surgery and corticoid treatment. The conclusion of the review was that rabbits are promising as a model of osteoporosis research because of their size, haversian remodelling and closure of epiphyseal plate, which solve some of the problems of the rat model. There are different techniques in the literature used to achieve the osteoporotic condition with diverse results, but there is a lack of consensus as to the best one.
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Affiliation(s)
- María Permuy
- Departamento de Anatomía, Producción Animal e Ciencias Clínicas Veterinarias, Universidade De Santiago de Compostela, Campus Universitario s/n, 27002, Lugo, Spain.
| | - Mónica López-Peña
- Departamento de Anatomía, Producción Animal e Ciencias Clínicas Veterinarias, Universidade De Santiago de Compostela, Campus Universitario s/n, 27002, Lugo, Spain
| | - Fernando Muñoz
- Departamento de Anatomía, Producción Animal e Ciencias Clínicas Veterinarias, Universidade De Santiago de Compostela, Campus Universitario s/n, 27002, Lugo, Spain
| | - Antonio González-Cantalapiedra
- Departamento de Anatomía, Producción Animal e Ciencias Clínicas Veterinarias, Universidade De Santiago de Compostela, Campus Universitario s/n, 27002, Lugo, Spain
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12
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Effect of psoralen on the expression of PPARγ, osteocalcin, and trabecular bone area in rabbits with steroid-induced avascular necrosis of the femoral head. J Orthop Surg Res 2019; 14:11. [PMID: 30621711 PMCID: PMC6325724 DOI: 10.1186/s13018-018-1054-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 12/27/2018] [Indexed: 12/03/2022] Open
Abstract
Objective Psoralen is a natural plant toxin which has the function of protecting fungi, insects, and herbivores. In this study, we aim to investigate the effect and mechanism of psoralen on steroid-induced avascular necrosis of femoral head (SANFH). Methods Thirty rabbits were randomly divided into blank group (n = 10), model group (n = 10), and experimental group (n = 10). Rabbits in blank and model groups were treated with normal saline, and rabbits in experimental group were treated with psoralen. Total RNA of bone marrow was extracted by trizol, and the mRNA expression of PPARγ and osteocalcin were detected by q-PCR. Then, the mRNA expression of PPARγ and osteocalcin in the three groups were compared. Western blot was used to detect the PPARγ protein expression in the bone of rabbits. ELISA was used to measure the osteocalcin protein. Results The mRNA expression of PPARγ in model group significantly increased compared with blank group. The mRNA expression of osteocalcin in model group decreased compared with blank group. However, the mRNA and protein expressions of PPARγ in experimental group were significantly decreased compared with the model group. The protein expressions of osteocalcin increased compared with the model group. There was no significant difference of trabecular bone area (TBA) between experimental and blank groups (P > 0.05). TBA in model group was lower than the experimental group (P < 0.05). There was no significant difference of TBA between experimental and blank groups (P > 0.05). Conclusion This research confirms that psoralen plays a positive role in the rehabilitation of SANFH.
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Liu S, Huang Y, Wang C, Tian S, Xu Y, Ge J. Epimedium protects steroid-induced avascular necrosis of femoral head in rats by inhibiting autophagy. Exp Ther Med 2018; 16:5047-5052. [PMID: 30542458 PMCID: PMC6257266 DOI: 10.3892/etm.2018.6827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 09/24/2018] [Indexed: 11/09/2022] Open
Abstract
The effect of epimedium extracting solution on bone mineral density (BMD) of steroid-induced avascular necrosis of femoral head (SANFH) in rats was evaluated to further explore its function mechanism. Twenty-four Sprague-Dawley (SD) rats (male/female: 1/1) were randomly divided into three groups: the control (n=8), the glucocorticoid (n=8) and the epimedium (n=8) group. Rats in the glucocorticoid and the epimedium group were injected with prednisolone acetate injection in gluteal muscles with 15 mg/kg/day twice a week. The epimedium group was given 10 ml/kg ephedra extracting solution containing crude drug with the concentration of 1.5 g/ml daily by gavage. After 6 weeks, all the experimental rats were sacrificed and materials were extracted. The expression of autophagy-related proteins were detected by observing the bone of the femoral head. After comparison of the control group with the model group in BMD, it was found that there were significant differences (P<0.05). There were no significant differences between the control and the epimedium group (P>0.05). Neither between the glucocorticoid and the epimedium group (P<0.05). Epimedium extracting solution can significantly enhance the BMD of femoral heads, prevent osteoporosis and lead to collapse, increase the expression of apoptotic and protective proteins and reduce the expression of autophagy-related proteins, thus providing a preliminary theoretical study for the prevention and treatment of SANFH.
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Affiliation(s)
- Su Liu
- Department of Orthopedics, Zhangjiagang Hospital Affiliated to Soochow University, Zhangjiagang, Jiangsu 215600, P.R. China
| | - Yunzong Huang
- Department of Orthopedics, Zhangjiagang Hospital Affiliated to Soochow University, Zhangjiagang, Jiangsu 215600, P.R. China
| | - Chuangli Wang
- Department of Orthopedics, Zhangjiagang Hospital Affiliated to Soochow University, Zhangjiagang, Jiangsu 215600, P.R. China
| | - Shoujing Tian
- Department of Orthopedics, Zhangjiagang Hospital Affiliated to Soochow University, Zhangjiagang, Jiangsu 215600, P.R. China
| | - Youjia Xu
- Department of Orthopedics, Zhangjiagang Hospital Affiliated to Soochow University, Zhangjiagang, Jiangsu 215600, P.R. China
| | - Jianfei Ge
- Department of Orthopedics, Zhangjiagang Hospital Affiliated to Soochow University, Zhangjiagang, Jiangsu 215600, P.R. China
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Li M, Zhang E, Lü L, Ban W, Dang X, Zhang C. [Effect and mechanisms of vitamin E on early steroid-induced avascular necrosis of femoral head in rats]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2018; 32:1421-1428. [PMID: 30417618 DOI: 10.7507/1002-1892.201801046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Objective To investigate the possibility of mitochondria-dependent apoptosis as a mechanism of early steroid-induced avascular necrosis of femoral head (SANFH) in rats and vitamin E as a possible prevention strategy. Methods Seventy-two male Sprague Dawley rats were randomly divided into control group, model group, and intervention group, with 24 rats in each group. The rats in control group were not treated as normal control. The rats in model group and intervention group were established early SANFH models by lipopolysaccharide combined with methylprednisolone injection. At the same time, the rats in intervention group were injected with vitamin E (40 mg/kg) every day for 7 days. At 2, 4, and 8 weeks after the final injection, the bilateral femoral heads were harvested and observed by HE staining, TUNEL assay, immunohistochemical staining, and Western blot. The rate of empty lacunae, apoptotic index, and the expressions of Caspase-9, Caspase-3, and cytochrome-c (Cyt-c) proteins were calculated. Results According to histological staining, there were significant differences in the rate of empty lacunae between intervention group and control group at 8 weeks ( P<0.05) and between intervention group and model group at 4 and 8 weeks ( P<0.05). The apoptotic index of intervention group was significantly lower than that of model group at each time point ( P<0.05). And there was significant difference between the intervention group and the control group at 8 weeks ( P<0.05). According to immunohistochemistry staining and Western blot, the expressions of Cyt-c, Caspase-9, and Caspase-3 all significantly decreased in intervention group than those in model group at each time point ( P<0.05); and the differences were significant between intervention group and control group at 8 weeks ( P<0.05). Conclusion Vitamin E can delay the progression of early SANFH by reducing mitochondrial dependent osteocyte apoptosis.
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Affiliation(s)
- Mufan Li
- The First Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Shaanxi, 710004, P.R.China
| | - Eryang Zhang
- The First Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Shaanxi, 710004, P.R.China
| | - Leifeng Lü
- The First Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Shaanxi, 710004, P.R.China
| | - Wenrui Ban
- The First Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Shaanxi, 710004, P.R.China
| | - Xiaoqian Dang
- The First Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Shaanxi, 710004, P.R.China
| | - Chen Zhang
- The First Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Shaanxi, 710004,
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Hardy RS, Zhou H, Seibel MJ, Cooper MS. Glucocorticoids and Bone: Consequences of Endogenous and Exogenous Excess and Replacement Therapy. Endocr Rev 2018; 39:519-548. [PMID: 29905835 DOI: 10.1210/er.2018-00097] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/08/2018] [Indexed: 02/02/2023]
Abstract
Osteoporosis associated with long-term glucocorticoid therapy remains a common and serious bone disease. Additionally, in recent years it has become clear that more subtle states of endogenous glucocorticoid excess may have a major impact on bone health. Adverse effects can be seen with mild systemic glucocorticoid excess, but there is also evidence of tissue-specific regulation of glucocorticoid action within bone as a mechanism of disease. This review article examines (1) the role of endogenous glucocorticoids in normal bone physiology, (2) the skeletal effects of endogenous glucocorticoid excess in the context of endocrine conditions such as Cushing disease/syndrome and autonomous cortisol secretion (subclinical Cushing syndrome), and (3) the actions of therapeutic (exogenous) glucocorticoids on bone. We review the extent to which the effect of glucocorticoids on bone is influenced by variations in tissue metabolizing enzymes and glucocorticoid receptor expression and sensitivity. We consider how the effects of therapeutic glucocorticoids on bone are complicated by the effects of the underlying inflammatory disease being treated. We also examine the impact that glucocorticoid replacement regimens have on bone in the context of primary and secondary adrenal insufficiency. We conclude that even subtle excess of endogenous or moderate doses of therapeutic glucocorticoids are detrimental to bone. However, in patients with inflammatory disorders there is a complex interplay between glucocorticoid treatment and underlying inflammation, with the underlying condition frequently representing the major component underpinning bone damage.
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Affiliation(s)
- Rowan S Hardy
- University of Birmingham, Birmingham, United Kingdom
| | - Hong Zhou
- Bone Research Program, ANZAC Research Institute, Sydney, New South Wales, Australia
| | - Markus J Seibel
- Bone Research Program, ANZAC Research Institute, Sydney, New South Wales, Australia.,Department of Endocrinology and Metabolism, Concord Repatriation General Hospital, Sydney, New South Wales, Australia.,Concord Clinical School, University of Sydney, Sydney, New South Wales, Australia
| | - Mark S Cooper
- Department of Endocrinology and Metabolism, Concord Repatriation General Hospital, Sydney, New South Wales, Australia.,Concord Clinical School, University of Sydney, Sydney, New South Wales, Australia.,Adrenal Steroid Laboratory, ANZAC Research Institute, Sydney, New South Wales, Australia
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16
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Safflower (Carthamus tinctorius L.) polysaccharide attenuates cellular apoptosis in steroid-induced avascular necrosis of femoral head by targeting caspase-3-dependent signaling pathway. Int J Biol Macromol 2018; 116:106-112. [PMID: 29729342 DOI: 10.1016/j.ijbiomac.2018.04.181] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/02/2018] [Accepted: 04/30/2018] [Indexed: 12/20/2022]
Abstract
The present study aimed to investigate the effects of a purified polysaccharide (SPS) from the safflower in a cellular model of steroid-associated necrosis of the femoral head (SANFH), which was established in primary murine osteoblasts suffering dexamethasone pretreatment. After treatment with SPS (25, 50 and 100 μg/ml), the degree of necrosis induced by dexamethasone was significantly reduced in osteoblasts as evidenced by an increase of cell viability and a decrease of apoptosis in osteoblasts. Furthermore, pretreatment with SPS (25, 50 and 100 μg/ml) significantly attenuated the activation of caspase-3 and cleavage of PARP relative to the model control cells. The addition of caspase-3 inhibitor (Z-DEVD-FMK) in dexamethasone-treated osteoblasts resulted in the inefficiency of SPS for inhibiting cellular apoptosis. Dose-dependent increases in alkaline phosphatase (ALP) activity, collagen synthesis and mineralization were also observed in SPS-treated osteoblasts at 72 h. The present study demonstrates that SPS may alleviate dexamethasone associated osteonecrosis by inhibiting caspsae-3-mediated apoptosis and may provide an alternative treatment for SANFH.
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17
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Tourkova IL, Liu L, Sutjarit N, Larrouture QC, Luo J, Robinson LJ, Blair HC. Adrenocorticotropic hormone and 1,25-dihydroxyvitamin D 3 enhance human osteogenesis in vitro by synergistically accelerating the expression of bone-specific genes. J Transl Med 2017; 97:1072-1083. [PMID: 28737765 PMCID: PMC5844701 DOI: 10.1038/labinvest.2017.62] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 04/14/2017] [Accepted: 05/01/2017] [Indexed: 12/16/2022] Open
Abstract
To improve definition of the physical and hormonal support of bone formation, we studied differentiation of human osteoblasts in vitro at varying combinations of ACTH, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D), and extracellular calcium, with and without added cortisol. Bone mineralization, alkaline phosphatase activity, and osteoblast-specific markers RunX2, osterix, and collagen I increased with 10 pM ACTH, 10 nM 1,25(OH)2D, or at 2 mM calcium with important synergistic activity of combinations of any of these stimuli. Signals induced by ACTH at 10-30 min included cAMP, TGF-β, and Erk1/2 phosphorylation. Affymetrix gene expression analysis showed that 2 h treatment of ACTH or 1,25(OH)2D increased the expression of bone regulating and structural mRNAs, including collagen I, biglycan, the vitamin D receptor, and TGF-β. Accelerating expression of these bone-specific genes was confirmed by quantitative PCR. Expression of 1,25(OH)2D 1α-hydroxylase (1α-hydroxylase) increased with 1,25(OH)2D, ACTH, and extracellular calcium from 0.5 to 2 mM. Unlike renal 1α-hydroxylase, in osteoblasts, 1α-hydroxylase activity is independent of parathyroid hormone. In keeping with calcium responsivity, calcium-sensing receptor RNA and protein increased with 10 nM ACTH or 1,25(OH)2D. Inclusion of 200 nM cortisol or 10 nM ACTH in differentiation media blunted osteoblasts alkaline phosphatase response to 1,25(OH)2D and calcium. Our results point to the importance of ACTH in bone maintenance and that extra skeletal (renal) 1,25(OH)2D is required for bone mineralization despite 1α-hydroxylase expression by osteoblasts.
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Affiliation(s)
- Irina L Tourkova
- The Pittsburgh Veterans Affairs Medical Center, Pittsburgh, PA, USA,Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Li Liu
- The Pittsburgh Veterans Affairs Medical Center, Pittsburgh, PA, USA,Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Nareerat Sutjarit
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Quitterie C Larrouture
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jianhua Luo
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lisa J Robinson
- Department of Pathology, West Virginia University School of Medicine, Morgantown, WV, USA,Department of Microbiology, Immunology & Cell Biology, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Harry C Blair
- The Pittsburgh Veterans Affairs Medical Center, Pittsburgh, PA, USA,Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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18
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Papachristou NI, Blair HC, Kypreos KE, Papachristou DJ. High-density lipoprotein (HDL) metabolism and bone mass. J Endocrinol 2017; 233:R95-R107. [PMID: 28314771 PMCID: PMC5598779 DOI: 10.1530/joe-16-0657] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 03/17/2017] [Indexed: 02/06/2023]
Abstract
It is well appreciated that high-density lipoprotein (HDL) and bone physiology and pathology are tightly linked. Studies, primarily in mouse models, have shown that dysfunctional and/or disturbed HDL can affect bone mass through many different ways. Specifically, reduced HDL levels have been associated with the development of an inflammatory microenvironment that affects the differentiation and function of osteoblasts. In addition, perturbation in metabolic pathways of HDL favors adipoblastic differentiation and restrains osteoblastic differentiation through, among others, the modification of specific bone-related chemokines and signaling cascades. Increased bone marrow adiposity also deteriorates bone osteoblastic function and thus bone synthesis, leading to reduced bone mass. In this review, we present the current knowledge and the future directions with regard to the HDL-bone mass connection. Unraveling the molecular phenomena that underline this connection will promote the deeper understanding of the pathophysiology of bone-related pathologies, such as osteoporosis or bone metastasis, and pave the way toward the development of novel and more effective therapies against these conditions.
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Affiliation(s)
- Nicholaos I Papachristou
- Department of Anatomy-Histology-EmbryologyUnit of Bone and Soft Tissue Studies, University of Patras Medical School, Patras, Greece
| | - Harry C Blair
- Department of PathologyUniversity of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh VA Medical CenterPittsburgh, Pennsylvania, USA
| | - Kyriakos E Kypreos
- Department of PharmacologyUniversity of Patras Medical School, Patras, Greece
| | - Dionysios J Papachristou
- Department of Anatomy-Histology-EmbryologyUnit of Bone and Soft Tissue Studies, University of Patras Medical School, Patras, Greece
- Department of PathologyUniversity of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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19
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Zaidi M, Sun L, Liu P, Davies TF, New M, Zallone A, Yuen T. Pituitary-bone connection in skeletal regulation. Horm Mol Biol Clin Investig 2017; 28:85-94. [PMID: 27508964 DOI: 10.1515/hmbci-2016-0015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/11/2016] [Indexed: 11/15/2022]
Abstract
Pituitary hormones have traditionally been thought to exert specific, but limited function on target tissues. More recently, the discovery of these hormones and their receptors in organs such as the skeleton suggests that pituitary hormones have more ubiquitous functions. Here, we discuss the interaction of growth hormone (GH), follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), prolactin, oxytocin and arginine vasopressin (AVP) with bone. The direct skeletal action of pituitary hormones therefore provides new insights and therapeutic opportunities for metabolic bone diseases, prominently osteoporosis.
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20
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Blair HC, Larrouture QC, Li Y, Lin H, Beer-Stoltz D, Liu L, Tuan RS, Robinson LJ, Schlesinger PH, Nelson DJ. Osteoblast Differentiation and Bone Matrix Formation In Vivo and In Vitro. TISSUE ENGINEERING PART B-REVIEWS 2016; 23:268-280. [PMID: 27846781 DOI: 10.1089/ten.teb.2016.0454] [Citation(s) in RCA: 267] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We review the characteristics of osteoblast differentiation and bone matrix synthesis. Bone in air breathing vertebrates is a specialized tissue that developmentally replaces simpler solid tissues, usually cartilage. Bone is a living organ bounded by a layer of osteoblasts that, because of transport and compartmentalization requirements, produce bone matrix exclusively as an organized tight epithelium. With matrix growth, osteoblasts are reorganized and incorporated into the matrix as living cells, osteocytes, which communicate with each other and surface epithelium by cell processes within canaliculi in the matrix. The osteoblasts secrete the organic matrix, which are dense collagen layers that alternate parallel and orthogonal to the axis of stress loading. Into this matrix is deposited extremely dense hydroxyapatite-based mineral driven by both active and passive transport and pH control. As the matrix matures, hydroxyapatite microcrystals are organized into a sophisticated composite in the collagen layer by nucleation in the protein lattice. Recent studies on differentiating osteoblast precursors revealed a sophisticated proton export network driving mineralization, a gene expression program organized with the compartmentalization of the osteoblast epithelium that produces the mature bone matrix composite, despite varying serum calcium and phosphate. Key issues not well defined include how new osteoblasts are incorporated in the epithelial layer, replacing those incorporated in the accumulating matrix. Development of bone in vitro is the subject of numerous projects using various matrices and mesenchymal stem cell-derived preparations in bioreactors. These preparations reflect the structure of bone to variable extents, and include cells at many different stages of differentiation. Major challenges are production of bone matrix approaching the in vivo density and support for trabecular bone formation. In vitro differentiation is limited by the organization and density of osteoblasts and by endogenous and exogenous inhibitors.
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Affiliation(s)
- Harry C Blair
- 1 Veteran's Affairs Medical Center , Pittsburgh, Pennsylvania.,2 Department of Pathology, University of Pittsburgh , Pittsburgh, Pennsylvania
| | | | - Yanan Li
- 3 Department of Stomatology, Chinese PLA General Hospital , Beijing, China
| | - Hang Lin
- 4 Department of Orthopaedic Surgery, Center for Cellular and Molecular Engineering, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Donna Beer-Stoltz
- 2 Department of Pathology, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Li Liu
- 2 Department of Pathology, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Rocky S Tuan
- 4 Department of Orthopaedic Surgery, Center for Cellular and Molecular Engineering, University of Pittsburgh , Pittsburgh, Pennsylvania
| | - Lisa J Robinson
- 5 Department of Pathology, West Virginia University School of Medicine , Morgantown, West Virginia.,6 Department of Microbiology, Immunology & Cell Biology, West Virginia University School of Medicine , Morgantown, West Virginia
| | - Paul H Schlesinger
- 7 Department of Cell Biology, Washington University , Saint Louis, Missouri
| | - Deborah J Nelson
- 8 Department of Neurobiology, Pharmacology & Physiology, University of Chicago , Chicago, Illinois
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21
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Xi H, Tao W, Jian Z, Sun X, Gong X, Huang L, Dong T. Levodopa attenuates cellular apoptosis in steroid-associated necrosis of the femoral head. Exp Ther Med 2016; 13:69-74. [PMID: 28123470 PMCID: PMC5245153 DOI: 10.3892/etm.2016.3964] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 09/22/2016] [Indexed: 11/23/2022] Open
Abstract
The present study aimed to investigate the effects of levodopa (LEV) on cellular apoptosis in a rabbit model of steroid-associated necrosis of the femoral head (SANFH). A total of 44 healthy adult Chinese rabbits were randomly divided into three groups: Group A (n=15), administered a combination of lipopolysaccharide and hormone to establish the SANFH animal model; group B (n=15), SANFH animal model as in group A orally administered LEV (0.4 g/kg/day) on the day of injection; and group C (n=14), the control group. On the 6th and 8th week of modeling, seven rabbits from each group were sacrificed to harvest bilateral femoral head specimens for hematoxylin and eosin staining and apoptosis detection by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay analysis, as well as for observing pathological changes and analyzing cellular apoptosis. Eight weeks after modeling, the serum insulin-like growth factor (IGF)-1 levels of the three groups were measured. The empty lacunae rate and apoptosis index of bone cells in the treatment group were significantly lower than that of the model group (P<0.01). Eight weeks after treatment, the serum levels of IGF-1 were significantly higher than that of the model group (P<0.01). These findings suggested that LEV was able to reduce steroid-induced bone cellular apoptosis, reduce the occurrence of necrosis of the femoral head and, through in vivo metabolism, it may promote the synthesis and release of IGF-1, which could be one of its biological pathways to prevent and treat SANFH.
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Affiliation(s)
- Hongbo Xi
- Department of Orthopaedics, Xiangcheng People's Hospital, Suzhou, Jiangsu 215131, P.R. China
| | - Weijian Tao
- Department of Orthopaedics, Xiangcheng People's Hospital, Suzhou, Jiangsu 215131, P.R. China
| | - Zhengguang Jian
- Department of Orthopaedics, Xiangcheng People's Hospital, Suzhou, Jiangsu 215131, P.R. China
| | - Xuefeng Sun
- Department of Orthopaedics, Xiangcheng People's Hospital, Suzhou, Jiangsu 215131, P.R. China
| | - Xiaohong Gong
- Department of Orthopaedics, Xiangcheng People's Hospital, Suzhou, Jiangsu 215131, P.R. China
| | - Lixin Huang
- Department of Orthopaedics, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, P.R. China
| | - Tianhua Dong
- Department of Orthopaedics, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, P.R. China
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The Role of (99m)Tc-Annexin V Apoptosis Scintigraphy in Visualizing Early Stage Glucocorticoid-Induced Femoral Head Osteonecrosis in the Rabbit. BIOMED RESEARCH INTERNATIONAL 2016; 2016:7067259. [PMID: 26989689 PMCID: PMC4771895 DOI: 10.1155/2016/7067259] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 01/17/2016] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To validate the ability of (99m)Tc-Annexin V to visualize early stage of glucocorticoid-induced femoral head necrosis by comparing with (99m)Tc-MDP bone scanning. METHODS Femoral head necrosis was induced in adult New Zealand white rabbits by intramuscular injection of methylprednisolone. (99m)Tc-Annexin scintigraphy and (99m)Tc-MDP scans were performed before and 5, 6, and 8 weeks after methylprednisolone administration. Rabbits were sacrificed at various time points and conducted for TUNEL and H&E staining. RESULTS All methylprednisolone treated animals developed femoral head necrosis; at 8 weeks postinjection, destruction of bone structure was evident in H&E staining, and apoptosis was confirmed by the TUNEL assay. This was matched by (99m)Tc-Annexin V images, which showed a significant increase in signal over baseline. Serial (99m)Tc-Annexin V scans revealed that increased (99m)Tc-Annexin V uptake could be observed in 5 weeks. In contrast, there was no effect on (99m)Tc-MDP signal until 8 weeks. The TUNEL assay revealed that bone cell apoptosis occurred at 5 weeks. CONCLUSION (99m)Tc-Annexin V is superior to (99m)Tc-MDP for the early detection of glucocorticoid-induced femoral head necrosis in the rabbit and may be a better strategy for the early detection of glucocorticoid-induced femoral head necrosis in patients.
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23
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Lin T, Liu J, Yang S, Liu X, Feng X, Fu D. Relation between the development of osteoporosis and osteonecrosis following glucocorticoid in a rabbit model. Indian J Orthop 2016; 50:406-13. [PMID: 27512223 PMCID: PMC4964774 DOI: 10.4103/0019-5413.185606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND There has been a recent increase in the number of patients suffering from bone and joint diseases, as a consequence of corticosteroids administration. There are more patients treated with low dose of GCs under long-term conditions in clinical, such as effect of GCs on Rheumatoid arthritis, Crohn's disease and Asthma patients. Hence, it was difficult for doctor to determine which problem occur first - OP or ON; however, there was no clinical report previously in the literature, and there was no effective animal model of OP and ON about low dose GCs. This study was conducted to develop rabbit models of glucocorticoid (GC)-induced femoral head ON and OP and to investigate the temporal relationship between the occurrence of the two events following administration of glucocorticoids. MATERIALS AND METHODS Fifty six, 6 months old female rabbits were randomly divided into the GC group and control group (C). Rabbits received gluteal injections of methylprednisolone sodium succinate once a day for 4 weeks, while normal saline solution in the control group. Rabbits were sacrificed at 0, 2, 4, and 8 weeks. Hip magnetic resonance imaging was performed before the rabbits were sacrificed. Serum calcium (Ca), phosphorus (P), total cholesterol, and triglyceride levels were also measured. The bone mineral density (BMD) of femoral head and the femoral shaft were measured by dual-energy X-ray absorptiometry. The trabecular parameters of the femur and the 4(th) lumbar vertebrae (L4) were measured with a micro-computed tomography (μ-CT). Also, the femoral head was stained with hematoxylin-eosin staining. RESULTS At 4 weeks in the GC group, the BMD of the femur reduced 33% and 22% in the femoral head and shaft; there was irregular intermediate to high T2-weighted images signals; μ-CT showed microfractures and cystic changes in the femoral head and L4 at 4 weeks. At 8 weeks in the GC group, the classical "line-like sign" indicating ON of the femoral head was observed in 64.3% of the rabbits. CONCLUSION A rabbit model of GC-induced OP and ON was developed by repetitive injection with small doses of GCs in the gluteal region. OP was observed at 4 weeks while ON developed at 8 weeks and followed a clear temporal pattern.
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Affiliation(s)
- Tao Lin
- Department of Orthopedics, Qilu Hospital of Shandong University, Jinan 250012, Shandong Province, China
| | - Junbin Liu
- Department of Traumatic Surgery, Jining No. 1 Peoples Hospital, Jining, Shandong 272011, China
| | - Shuhua Yang
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xianzhe Liu
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaobo Feng
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dehao Fu
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China,Address for correspondence: Prof. Dehao Fu, Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China. E-mail:
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Scott A, Choi K, Mookherjee N, Hoppa R, Larcombe L. The biochemical signatures of stress: A preliminary analysis of osteocalcin concentrations and macroscopic skeletal changes associated with stress in the 13th - 17th centuries black friars population. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2015; 159:596-606. [DOI: 10.1002/ajpa.22915] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/12/2015] [Accepted: 11/19/2015] [Indexed: 11/09/2022]
Affiliation(s)
- A.B. Scott
- Department of Anthropology; University of Manitoba; Winnipeg MB R3T 2N2 Canada
| | - K.Y. Choi
- Department of Immunology; University of Manitoba; Winnipeg MB R3E 0T5 Canada
| | - N. Mookherjee
- Department of Immunology; University of Manitoba; Winnipeg MB R3E 0T5 Canada
| | - R.D. Hoppa
- Department of Anthropology; University of Manitoba; Winnipeg MB R3T 2N2 Canada
| | - L.A. Larcombe
- Department of Anthropology; University of Manitoba; Winnipeg MB R3T 2N2 Canada
- Department of Internal Medicine; University of Manitoba; Winnipeg MB R3T 2N2 Canada
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Zhang C, Zou YL, Ma J, Dang XQ, Wang KZ. Apoptosis associated with Wnt/β-catenin pathway leads to steroid-induced avascular necrosis of femoral head. BMC Musculoskelet Disord 2015; 16:132. [PMID: 26037065 PMCID: PMC4453221 DOI: 10.1186/s12891-015-0606-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 05/28/2015] [Indexed: 12/27/2022] Open
Abstract
Background The objective of the current study was to establish a rat model to investigate apoptosis in steroid-induced femoral head osteonecrosis occurring via the Wnt/β-catenin pathway. Methods Male Sprague–Dawley (SD) rats were randomly divided into a control group (group A), model group (group B) and sFRP1 group (group C), each consisting of 24 rats, and the rats were intravenously injected with LPS (10 μg/kg body weight). After 24 h, three injections of MPS (20 mg/kg body weight) were administered intramuscularly at 24-h intervals. The rats in group C were injected intramuscularly with 1 μg/kg sFRP1 protein per day for 30 days, beginning at the time of the first MPS administration. The group A rats were fed and housed under identical conditions but received saline injection. All animals were sacrificed at weeks 2, 4 and 8 from the first MPS injection. Histopathological staining was preformed to evaluated osteonecrosis. Apoptosis was detected via quantitative terminal deoxynucleotidyl transferase (TdT) deoxyuridine triphosphate nick-end labelling (TUNEL) staining, caspase-3 activity assay, and detection of Bcl-2 and Bax protein expression by immunohistochemistry and Western blotting. Wnt/β-catenin pathway signalling molecules, including activated β-catenin and c-Myc, were detected by immunohistochemistry and Western blotting. Results Typical osteonecrosis was observed in groups B and C. Apoptosis gradually increased with increasing time in both groups B and C. More severe osteonecrosis and apoptosis were observed in group C compared with group B. The expression levels of caspase-3 and Bax were higher while that of Bcl-2 was lower in group C compared with group B. The expression levels of activated β-catenin and c-Myc gradually decreased with increasing time in both groups B and C, and they were lower in group C compared with group B. Conclusions The Wnt/β-catenin pathway is involved in the pathogenesis of early stage SANFH, as we have demonstrated in an SANFH rat model, and it may act through the regulation of c-Myc, which affects the cell cycle and cell apoptosis. Electronic supplementary material The online version of this article (doi:10.1186/s12891-015-0606-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chen Zhang
- The First Department of Orthopaedics, the Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, No.157 Xiwu Road, Xi'an, Shaanxi Province, 710004, P. R. China.
| | - Yu-Long Zou
- Department of Orthopaedics, Chongqing Medical University, Chongqing, 400010, P. R. China.
| | - Jun Ma
- The First Department of Orthopaedics, the Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, No.157 Xiwu Road, Xi'an, Shaanxi Province, 710004, P. R. China.
| | - Xiao-Qian Dang
- The First Department of Orthopaedics, the Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, No.157 Xiwu Road, Xi'an, Shaanxi Province, 710004, P. R. China.
| | - Kun-Zheng Wang
- The First Department of Orthopaedics, the Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, No.157 Xiwu Road, Xi'an, Shaanxi Province, 710004, P. R. China.
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Bai R, Liu W, Zhao A, Zhao Z, Jiang D. Nitric oxide content and apoptosis rate in steroid-induced avascular necrosis of the femoral head. Exp Ther Med 2015; 10:591-597. [PMID: 26622359 DOI: 10.3892/etm.2015.2521] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 03/31/2015] [Indexed: 01/16/2023] Open
Abstract
The aim of the present study was to explore the effect on nitric oxide (NO) content and osteocyte apoptosis of steroid-induced avascular necrosis of the femoral head (SANFH) in an animal model of SANFH. A total of 40 Japanese white rabbits, 5 months of age and weighing 2.5±0.5 kg, were randomly divided into groups A (hormone + endotoxin group), B (endotoxin + normal saline group), C (normal saline + hormone group) and D (control group). Following the establishment of the model, a blood sample was taken from the heart of each animal and centrifuged; the levels of NO in the serum were detected. The bilateral femoral heads were conventionally dissected, fixed, decalcified and stained with hematoxylin and eosin. Subsequently, the empty bone lacunae were counted under an optical microscope. Changes in osteocyte morphology were observed using electron microscopy and osteocyte apoptosis was detected with a terminal deoxynucleotidyl transferase dUTP nick end labeling assay. The percentage of empty bone lacunae in group A was significantly higher compared with that in groups B, C and D (P<0.01); however, there was no significant difference in percentage among groups B, C and D. The NO content in group A was significantly higher compared with that in groups B, C and D (P<0.01); however, there was no significant difference in NO content among groups B, C and D. The osteocyte apoptosis index in group A was significantly higher compared with that in the other groups (P<0.01); there was no significant difference among groups B, C and D. NO content was positively correlated with osteocyte apoptosis index (r=0.707). Thus, the present study found that NO content and the osteocyte apoptosis index were increased in SANFH, and that they play an important role in SANFH. The content of NO was positively correlated with the osteocyte apoptosis index, indicating that NO induces apoptosis.
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Affiliation(s)
- Rui Bai
- Graduate School of Chongqing Medical University, Chongqing, P.R. China
| | - Wanlin Liu
- Department of Pediatric Orthopedics, Second Affiliated Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia, P.R. China
| | - Aiqing Zhao
- Department of Computed Tomography, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia, P.R. China
| | - Zhengqun Zhao
- Department of Pediatric Orthopedics, Second Affiliated Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia, P.R. China
| | - Dianming Jiang
- Department of Orthopedics, First Affiliated Hospital of Chongqing Medical University, Chongqing, P.R. China
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Feng M, Zhang R, Gong F, Yang P, Fan L, Ni J, Bi W, Zhang Y, Wang C, Wang K. Protective effects of necrostatin-1 on glucocorticoid-induced osteoporosis in rats. J Steroid Biochem Mol Biol 2014; 144 Pt B:455-62. [PMID: 25220755 DOI: 10.1016/j.jsbmb.2014.09.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 09/02/2014] [Accepted: 09/04/2014] [Indexed: 12/26/2022]
Abstract
The inhibition of bone formation has been suggested to play a central role in the pathogenesis of glucocorticoid-induced osteoporosis (GIOP). Recently, many studies suggested that there may be another mechanism involved in GIOP besides apoptosis. The aim of this study was to investigate the protective effect of Necrostatin-1 on GIOP rats. Forty male Sprague-Dawley rats were randomly divided into four groups (n=10): controls; GIOP rats; GIOP rats pretreated with alendronate; and GIOP rats pretreated with Necrostatin-1. Their bone mineral density (BMD) and body weight were measured at the beginning and at the end of the experiment. TUNEL assay, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to observe the change of cellular morphology induced by Nec-1. The biochemical analysis and histomorphometric analysis were used to evaluate the change of bone formation by Nec-1. RIP-1, RIP-3 and caspase-8 expression were evaluated by immunohistochemistry. We found more TUNEL positive osteocytes and larger lacunae volume in GIOP rats compared with the control group. However, most of the osteocytes displayed a necrotic morphology and mitochondria lesions under TEM. In contrast to alendronate, Necrostatin-1 significantly elevated the level of bone formation markers, while it had no effect on bone resorption markers. Necrostatin-1 also markedly ameliorated trabecular bone. In addition, Necrostatin-1 significantly weaken the immunoreactivity of RIP-1 in GIOP rats while had no effect on RIP-3 and caspase-8. These data suggest, for the first time, that Necrostatin-1 accelerate bone formation of glucocorticoid-induced osteoporosis in rats.
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Affiliation(s)
- Min Feng
- Department of Orthopaedics, Second Affiliated Hospital of Xi'an Jiaotong University No.157 Xiwu Road, Xi'an, Shaanxi Province, PR China
| | - RuiRui Zhang
- Department of ICU, 521 Healthy Institutes of North Industries, No. 12 Zhangbadong Road, Xi'an, Shaanxi Province, PR China
| | - Futai Gong
- Department of Orthopaedics, Chinese Medicine Hospital of Xi'an, No. 325 Dongda Street, Xi'an, Shaanxi Province, PR China
| | - Pei Yang
- Department of Orthopaedics, Second Affiliated Hospital of Xi'an Jiaotong University No.157 Xiwu Road, Xi'an, Shaanxi Province, PR China
| | - Lihong Fan
- Department of Orthopaedics, Second Affiliated Hospital of Xi'an Jiaotong University No.157 Xiwu Road, Xi'an, Shaanxi Province, PR China
| | - Jianlong Ni
- Department of Orthopaedics, Second Affiliated Hospital of Xi'an Jiaotong University No.157 Xiwu Road, Xi'an, Shaanxi Province, PR China
| | - Wenchao Bi
- Department of Orthopaedics, Second Affiliated Hospital of Xi'an Jiaotong University No.157 Xiwu Road, Xi'an, Shaanxi Province, PR China
| | - Yongtao Zhang
- Department of Orthopaedics, Second Affiliated Hospital of Xi'an Jiaotong University No.157 Xiwu Road, Xi'an, Shaanxi Province, PR China
| | - ChunSheng Wang
- Department of Orthopaedics, Second Affiliated Hospital of Xi'an Jiaotong University No.157 Xiwu Road, Xi'an, Shaanxi Province, PR China
| | - KunZheng Wang
- Department of Orthopaedics, Second Affiliated Hospital of Xi'an Jiaotong University No.157 Xiwu Road, Xi'an, Shaanxi Province, PR China.
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Abstract
Bone fragility is a major health concern, as the increased risk of bone fractures has devastating outcomes in terms of mortality, decreased autonomy, and healthcare costs. Efforts made to address this problem have considerably increased our knowledge about the mechanisms that regulate bone formation and resorption. In particular, we now have a much better understanding of the cellular events that are triggered when bones are mechanically stimulated and how these events can lead to improvements in bone mass. Despite these findings at the molecular level, most exercise intervention studies reveal either no effects or only minor benefits of exercise programs in improving bone mineral density (BMD) in osteoporotic patients. Nevertheless, and despite that BMD is the gold standard for diagnosing osteoporosis, this measure is only able to provide insights regarding the quantity of bone tissue. In this article, we review the complex structure of bone tissue and highlight the concept that its mechanical strength stems from the interaction of several different features. We revisited the available data showing that bone mineralization degree, hydroxyapatite crystal size and heterogeneity, collagen properties, osteocyte density, trabecular and cortical microarchitecture, as well as whole bone geometry, are determinants of bone strength and that each one of these properties may independently contribute to the increased or decreased risk of fracture, even without meaningful changes in aBMD. Based on these findings, we emphasize that while osteoporosis (almost) always causes bone fragility, bone fragility is not always caused just by osteoporosis, as other important variables also play a major role in this etiology. Furthermore, the results of several studies showing compelling data that physical exercise has the potential to improve bone quality and to decrease fracture risk by influencing each one of these determinants are also reviewed. These findings have meaningful clinical repercussions as they emphasize the fact that, even without leading to improvements in BMD, exercise interventions in patients with osteoporosis may be beneficial by improving other determinants of bone strength.
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Xu X, Wen H, Hu Y, Yu H, Zhang Y, Chen C, Pan X. STAT1-caspase 3 pathway in the apoptotic process associated with steroid-induced necrosis of the femoral head. J Mol Histol 2014; 45:473-85. [PMID: 24554068 DOI: 10.1007/s10735-014-9571-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 02/11/2014] [Indexed: 12/15/2022]
Abstract
Osteocyte apoptosis is the main manifestation of steroid-induced avascular necrosis of the femoral head (SANFH). STAT1 and caspase 3 participate in the process of apoptosis and STAT1 upregulates the expression of caspase 3. We examined the relationship between the STAT1-caspase 3 pathway and apoptosis in SANFH. All specimens were divided into four groups: the negative control group, Ficat I-II group, Ficat III group, and Ficat IV-V group, and examined histologically, with a TUNEL assay, immunohistochemically, with a caspase 3 activity assay, with ELISAs of STAT1 and phospo-STAT1 (p-STAT1), with a western blotting analysis of p-STAT1 and with real-time RT-PCR. The proportion of empty lacunae increased significantly with the development of SANFH. The proportion of TUNEL-positive cells and immunohistochemical analysis of caspase 3 also increased significantly, although the Ficat I-II group did not differ significantly from the negative control group. Immunohistochemical analysis of STAT1 and p-STAT1, caspase 3 activity all showed significant differences among the groups. An ELISA and a western blotting analysis of p-STAT1 showed significant differences among the groups. An ELISA of STAT1, real-time RT-PCR analysis of caspase 3 and STAT1 all showed significant differences among the groups except between the Ficat I-II and negative control groups. The correlation analysis showed strong positive relationships between the proportion of empty lacunae and the proportion of TUNEL-positive cells between caspase 3 activity and the proportion of TUNEL-positive cells and between the levels of p-STAT1 protein and caspase 3 mRNA. The apoptotic process in SANFH develops with the upregulated expression of caspase 3 via the expression and activation of STAT1. The STATI-caspase 3 pathway plays a critical role in the development of SANFH.
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Affiliation(s)
- Xinxian Xu
- Osteopathy Department, Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
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Tian L, Dang XQ, Wang CS, Yang P, Zhang C, Wang KZ. Effects of sodium ferulate on preventing steroid-induced femoral head osteonecrosis in rabbits. J Zhejiang Univ Sci B 2014; 14:426-37. [PMID: 23645179 DOI: 10.1631/jzus.b1200311] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The aim of this study is to investigate the effects and possible mechanisms of sodium ferulate (SF) on anti-apoptosis in steroid-induced femoral head osteonecrosis in rabbits. Japanese white rabbits were randomly divided into three groups (control group, treatment group, and model group), each with 24 rabbits. The model and treatment groups were first injected with an intravenous dose of horse serum, 10 ml/kg, three weeks later with an intravenous dose of 7.5 ml/kg, and two weeks later with an intramuscular dose of methylprednisolone, 45 mg/kg, three times in order to establish rabbit models of osteonecrosis. Concurrently, the treatment group was injected with intravenous doses of SF 20 mg/kg for two weeks, once per day. Three time points, Weeks 2, 4, and 8, were selected after modeling was completed. Osteonecrosis was verified by histopathology with haematoxylin-eosin (HE) staining. The apoptosis rate of osteonecrosis was observed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The apoptosis expressions of caspase-3 and Bcl-2 were analyzed by immunohistochemistry and Western blot. The rabbit models of osteonecrosis were successfully established and observed by HE staining. SF was effective in intervening in apoptosis and decreasing the apoptosis rate in femoral head necrosis by the immunohistochemistry and TUNEL assay (P<0.01). Western blot analysis indicated that there were statistical significances in the protein levels of caspase-3 and Bcl-2 (P<0.01). SF has a protective effect by reducing the incidence of early steroid-induced femoral head necrosis in rabbits, effectively intervening in apoptosis through decreasing caspase-3 expression and up-regulating Bcl-2 expression.
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Affiliation(s)
- Lei Tian
- Department of Orthopedics, the Second Affiliated Hospital, College of Medicine, Xi'an Jiaotong University, Xi'an 710004, China
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31
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Abstract
Apoptotic death of osteocytes was recognized over 15 years ago, but its significance for bone homeostasis has remained elusive. A new paradigm has emerged that invokes osteocyte apoptosis as a critical event in the recruitment of osteoclasts to a specific site in response to skeletal unloading, fatigue damage, estrogen deficiency and perhaps in other states where bone must be removed. This is accomplished by yet to be defined signals emanating from dying osteocytes, which stimulate neighboring viable osteocytes to produce osteoclastogenic cytokines. The osteocyte apoptosis caused by chronic glucocorticoid administration does not increase osteoclasts; however, it does negatively impact maintenance of bone hydration, vascularity, and strength.
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Affiliation(s)
- Robert L Jilka
- Division of Endocrinology & Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, Central Arkansas Veterans Healthcare System, 4301 W. Markham, Slot 587, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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Abstract
Awareness of the need for prevention of glucocorticoid-induced fractures is growing, but glucocorticoid administration is often overlooked as the most common cause of nontraumatic osteonecrosis. Glucocorticoid-induced osteonecrosis develops in 9-40% of patients receiving long-term therapy although it may also occur with short-term exposure to high doses, after intra-articular injection, and without glucocorticoid-induced osteoporosis. The name, osteonecrosis, is misleading because the primary histopathological lesion is osteocyte apoptosis. Apoptotic osteocytes persist because they are anatomically unavailable for phagocytosis and, with glucocorticoid excess, decreased bone remodeling retards their replacement. Glucocorticoid-induced osteocyte apoptosis, a cumulative and unrepairable defect, uniquely disrupts the mechanosensory function of the osteocyte-lacunar-canalicular system and thus starts the inexorable sequence of events leading to collapse of the femoral head. Current evidence indicates that bisphosphonates may rapidly reduce pain, increase ambulation, and delay joint collapse in patients with osteonecrosis.
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Affiliation(s)
- Robert S Weinstein
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, Central Arkansas Veterans Healthcare System, University of Arkansas for Medical Sciences, Little Rock, AR 72205-7199, USA.
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Blair HC, Robinson LJ, Huang CLH, Sun L, Friedman PA, Schlesinger PH, Zaidi M. Calcium and bone disease. Biofactors 2011; 37:159-67. [PMID: 21674636 PMCID: PMC3608212 DOI: 10.1002/biof.143] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 12/18/2010] [Indexed: 11/12/2022]
Abstract
Calcium transport and calcium signaling are of basic importance in bone cells. Bone is the major store of calcium and a key regulatory organ for calcium homeostasis. Bone, in major part, responds to calcium-dependent signals from the parathyroids and via vitamin D metabolites, although bone retains direct response to extracellular calcium if parathyroid regulation is lost. Improved understanding of calcium transporters and calcium-regulated cellular processes has resulted from analysis of genetic defects, including several defects with low or high bone mass. Osteoblasts deposit calcium by mechanisms including phosphate and calcium transport with alkalinization to absorb acid created by mineral deposition; cartilage calcium mineralization occurs by passive diffusion and phosphate production. Calcium mobilization by osteoclasts is mediated by acid secretion. Both bone forming and bone resorbing cells use calcium signals as regulators of differentiation and activity. This has been studied in more detail in osteoclasts, where both osteoclast differentiation and motility are regulated by calcium.
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Affiliation(s)
- Harry C Blair
- Department of Pathology, University of Pittsburgh, Veterans Affairs Health System, PA, USA.
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Renedo RJG, Sousa MM, Pérez SF, Zabalbeascoa JR, Carro LP. Avascular necrosis of the femoral head in patients with Hodgkin's disease. Hip Int 2011; 20:473-81. [PMID: 21157752 DOI: 10.1177/112070001002000410] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/24/2010] [Indexed: 02/04/2023]
Abstract
Avascular necrosis of the femoral head (ANFH) is a rare complication that may occur in patients diagnosed with Hodgkin's Disease (HD), as a result of treatment. A review was made of 315 cases of HD treated with systemic chemotherapy associated with high doses of steroids and radiation therapy and 18 patients (5.71%) were found to have developed ANFH during treatment. The mean follow-up time for chemotherapy was 40 months (range 20-110 months) with an average dose of prednisone of 8.45 g (range 3.20 - 18.50). The patients were treated by simple forage, simple forage plus IES and total hip arthroplasty (THA). In 8 cases (44.44%) forage associated with IES was performed as the initial treatment option and 6 of these cases were found to be in Ficat stage II (75%), 1 was found to be in stage III (12.55%) and another in stage IV (12.5%). In 2 cases, the central decompression technique was used (Simple Forage); both were in Ficat stage II. In the other 8 cases, a total hip arthroplasty (THA) was chosen as the initial treatment option, with 3 of these patients in Ficat stage III and 5 in Ficat stage IV. The clinical outcomes (time to postoperative pain, time to radiological failure, and time to arthroplasty from the forage) following surgical management using the forage-biopsy technique with and without internal electrostimulation (IES) were recorded. We observed that treatment with Forage + IES was better than simple Forage in stages below III in patients with Hodgkin's Disease. We considered that in Ficat stage III and IV arthroplasty (THA) was the better option. Steroids do not appear to be the only factor that worsens the outcomes of the parameters tested, and, in our opinion, other associated factors exist.
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Affiliation(s)
- Raúl J G Renedo
- Facultativo Especialista Cirugía Ortopédica y Traumatología, Hospital Marques de Valdecilla, Santander, Spain.
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35
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Baofeng L, Zhi Y, Bei C, Guolin M, Qingshui Y, Jian L. Characterization of a rabbit osteoporosis model induced by ovariectomy and glucocorticoid. Acta Orthop 2010; 81:396-401. [PMID: 20446884 PMCID: PMC2876847 DOI: 10.3109/17453674.2010.483986] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND AND PURPOSE Experimental models of osteoporosis in rabbits are useful to investigate anabolic agents because rabbits have an active Haversian remodeling and achieve skeletal maturity quickly. In this study, an experimental model of osteoporosis in rabbits induced by a combination of ovariectomy and glucocorticoid was characterized to provide a useful model for prevention and therapy of osteoporosis. METHODS 32 skeletally mature female rabbits were divided randomly into 4 groups: sham control, bilateral ovariectomy (OVX), 1mg/kg/day methylprednisolone (MP) for 8 weeks, and OVX in combination with MP. All rabbits were killed 10 weeks after surgery. Bone mineral density (BMD) of lumbar spine was measured by dual-energy X-ray absorptiometry at baseline, and at 6 and 10 weeks postoperatively. Bone microarchitecture and mechanical properties of lumbar vertebrae were investigated by high-resolution micro-computed tomography and compression test, respectively, after killing. RESULTS Mean BMD of the OVX+MP group at 10 weeks was reduced by about 36% from baseline (p < 0.001). Bone microarchitecture of lumbar vertebrae in the OVX+MP group indicated osteoporosis-associated deterioration. There was a statistically significant reduction in maximum load, stiffness, and energy absorption capacity of lumbar vertebrae in the OVX+MP group, but not in the OVX group, compared to the sham control. In the MP group, BMD and some microarchitecture parameters such as trabecular thickness and bone volume fraction were reduced. The mechanical properties were not statistically significantly different from those in the sham control group, however, although a negative trend was observed. INTERPRETATION Osteopenia can be induced experimentally in rabbits through a combination of OVX and MP, and can be evaluated by BMD, bone microstructure, and mechanical parameters.
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Affiliation(s)
| | - Yuan Zhi
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi'an
| | - Chen Bei
- Department ofOncology, Guangzhou General Hospital of Guangzhou Military Command, GuangzhouChina
| | - Meng Guolin
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi'an
| | - Yin Qingshui
- Department of Orthopaedics, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou
| | - Liu Jian
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, Xi'an
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Abstract
Adrenocorticotropin (ACTH) is one of several peptide hormones derived from a larger molecule, proopiomelanocortin (POMC). ACTH is a classic endocrine hormone, processed and secreted from the pituitary to stimulate cortisol production from the fasciculata cells in the adrenal gland. However, ACTH is also produced by other cells, including macrophages, at many sites in the body. ACTH binds to a specific member of the melanocortin receptor family, the MC2R. MC2R is expressed in osteoblastic cells in vivo, as shown by in situ hybridization. MC2R expression is strongest at sites of active bone deposition, and thus ACTH response probably varies with osteoblastic activity or stage of osteoblast differentiation. In vitro ACTH stimulates proliferation of osteoblasts in a dose-dependent manner. ACTH at 10 nM increases collagen I mRNA in the osteoblastic cell line SaOs2, although at lower concentrations ACTH may oppose osteoblast differentiation. ACTH is thus, at high concentrations, anabolic for the osteoblast, and it is highly likely that the hormone has concentration-dependent effects on bone metabolism in vivo.
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Affiliation(s)
- Carlos M Isales
- Department of Orthopaedic Surgery, Medical College of Georgia, Augusta, Georgia, USA.
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37
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Abstract
We report that adrenocorticotropic hormone (ACTH) protects against osteonecrosis of the femoral head induced by depot methylprednisolone acetate (depomedrol). This therapeutic response likely arises from enhanced osteoblastic support and the stimulation of VEGF by ACTH; the latter is largely responsible for maintaining the fine vascular network that surrounds highly remodeling bone. We suggest examining the efficacy of ACTH in preventing human osteonecrosis, a devastating complication of glucocorticoid therapy.
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Ko JY, Wang FS, Wang CJ, Wong T, Chou WY, Tseng SL. Increased Dickkopf-1 expression accelerates bone cell apoptosis in femoral head osteonecrosis. Bone 2010; 46:584-91. [PMID: 19895917 DOI: 10.1016/j.bone.2009.10.030] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Revised: 10/26/2009] [Accepted: 10/26/2009] [Indexed: 12/11/2022]
Abstract
Intensive bone cell apoptosis contributes to osteonecrosis of femoral head (ONFH). Dickkopf-1 (DKK1) reportedly mediates various types of skeletal disorders. This study investigated whether DKK1 was linked to the occurrence of ONFH. Thirty-nine patients with various stages of ONFH were recruited. Bone specimens were harvested from 34 ONFH patients underwent hip arthroplasty, and from 10 femoral neck fracture patients. Bad, Bcl2 TNFalpha, DKK1, Wnt3a, LRP5, and Axin1 expressions were analyzed by quantitative RT-PCR and ELISA. Apoptotic cells were assayed using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labelling (TUNEL). Primary bone-marrow mesenchymal cells were treated with DKK1 RNA interference and recombinant DKK1 protein. ONFH patients with the histories of being administrated corticosteroids and excessive alcohol consumption had significantly higher Bad and DKK1 mRNA expressions in bone tissue and DKK1 abundances in serum than femoral neck fracture patients. Bone cells adjacent to osteonecrotic bone displayed strong DKK1 immunoreactivity and TUNEL staining. Increased DKK1 expression in bone tissue and serum correlated with Bad expression and TUNEL staining. Serum DKK1 abundance correlated with the severity of ONFH. The DKK1 RNA interference and recombinant DKK1 protein regulated Bad expression and apoptosis of primary bone-marrow mesenchymal cells. Knock down of DKK1 reduced dexamethasone-induced apoptosis of mesenchymal cells. Taken together, promoted DKK1 expression was associated with bone cell apoptosis in the occurrence of ONFH patients with the histories of corticosteroid and alcohol intake and progression of ONFH. DKK1 expression in injured tissue provides new insight into ONFH pathogenesis.
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Affiliation(s)
- Jih-Yang Ko
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Niao-Sung, Kaohsiung 833, Taiwan
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39
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Takei T, Itabashi M, Tsukada M, Sugiura H, Moriyama T, Kojima C, Shiohira S, Shimizu A, Karasawa K, Amemiya N, Kawanishi K, Ogawa T, Uchida K, Tsuchiya K, Nitta K. Risedronate therapy for the prevention of steroid-induced osteoporosis in patients with minimal-change nephrotic syndrome. Intern Med 2010; 49:2065-70. [PMID: 20930431 DOI: 10.2169/internalmedicine.49.3707] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Minimal-change nephrotic syndrome (MCNS) is treated by the administration of prednisolone (PSL) at high doses. Steroid-induced osteoporosis is a serious adverse effect of this drug. METHODS Patients with MCNS were randomly assigned to two groups, the risedronate (2.5 mg/day) + alfacalcidol (0.25 µg/day) group (n=20) and the alfacalcidol (0.25 µg/day)-alone group (n=20). All the patients had received PSL and the clinical characteristics were compared between the two groups at baseline and at 12 months. RESULTS A significant decrease of the mean bone mineral density (BMD) of the lumbar spine from 0.710±0.162 (g/cm(2)) to 0.588±0.125 was observed in the alfacalcidol-alone group (p=0.02), while no such decrease of the bone mineral density was found in the risedronate + alfacalcidol group (0.663±0.169 at baseline and 0.626±0.129 at 12 months). No significant differences in the results of other biochemical tests performed at the baseline and at 12 months were observed between the two groups. The likelihood of development of steroid-induced osteoporosis was influenced by the cumulative dose of PSL, the mean BMD at the baseline, occurrence of disease relapse, and risedronate therapy. CONCLUSION Risedronate appears to be effective in preventing steroid-induced osteoporosis. It is necessary to use bisphosphonates to maintain the BMD in patients with MCNS receiving prolonged steroid therapy.
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Affiliation(s)
- Takashi Takei
- Department of Medicine, Kidney Center, Tokyo Women's Medical University.
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40
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41
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Atkins GJ, Welldon KJ, Halbout P, Findlay DM. Strontium ranelate treatment of human primary osteoblasts promotes an osteocyte-like phenotype while eliciting an osteoprotegerin response. Osteoporos Int 2009; 20:653-64. [PMID: 18763010 DOI: 10.1007/s00198-008-0728-6] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 07/21/2008] [Indexed: 10/21/2022]
Abstract
SUMMARY The effect of strontium ranelate (SR) on human osteoblast differentiation was tested. SR induced osteoblastic proliferation, in vitro mineralization, and increased the expression of osteocyte markers. SR also elicited an osteoprotegerin (OPG) secretory response. We conclude that SR promotes the osteoblast maturation and osteocyte differentiation while promoting an additional antiresorptive effect. INTRODUCTION SR is a new treatment for osteoporosis that reduces the risk of hip and vertebral fractures in postmenopausal women. This study sought to investigate the extent, to which SR modulates human osteoblast differentiation. METHODS Adult human primary osteoblasts (NHBC) were exposed to SR under mineralizing conditions in long-term cultures. Osteoblast differentiation status was investigated by cell-surface phenotypic analysis. Expression of genes associated with osteoblast/osteocyte differentiation was examined using real-time RT-PCR. Secreted OPG was assayed by enzyme-linked immunosorbent assay. RESULTS SR significantly increased osteoblast replication. SR time- and dose-dependently induced an osteocyte-like phenotype, as determined by cell surface alkaline phosphatase and STRO-1 expression. SR at 5 mM or greater dramatically increased in vitro mineralization. In parallel, mRNA levels of dentin matrix protein (DMP)-1 and sclerostin were higher under SR treatment, strongly suggestive of the presence of osteocytes. SR also increased the OPG/RANKL ratio throughout the culture period, consistent with an effect to inhibit osteoblast-induced osteoclastogenesis. CONCLUSIONS This study suggests that SR can promote osteoblast maturation and an osteocyte-like phenotype. Coupled with its effect on the OPG/RANKL system, these findings are consistent with in vivo effects in patients receiving SR for the treatment of osteoporosis.
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Affiliation(s)
- G J Atkins
- Bone Cell Biology Group, Discipline of Orthopaedics and Trauma, University of Adelaide and Hanson Institute, Adelaide, Australia.
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42
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Blair HC, Zaidi M, Huang CLH, Sun L. The developmental basis of skeletal cell differentiation and the molecular basis of major skeletal defects. Biol Rev Camb Philos Soc 2008; 83:401-15. [PMID: 18710437 DOI: 10.1111/j.1469-185x.2008.00048.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vertebrate skeletal differentiation retains elements from simpler phyla, and reflects the differentiation of supporting tissues programmed by primary embryonic development. This developmental scheme is driven by homeotic genes expressed in sequence, with subdivision of skeletal primordia driven by a combination of seven transmembrane-pass receptors responding to Wnt-family signals, and by bone morphogenetic family signals that define borders of individual bones. In sea-dwelling vertebrates, an essentially complete form of the skeleton adapted by the land-living vertebrates develops in cartilage, based on type II collagen and hydrophilic proteoglycans. In bony fishes, this skeleton is mineralized to form a solid bony skeleton. In the land-living vertebrates, most of the skeleton is replaced by an advanced vascular mineralized skeleton based on type I collagen, which reduces skeletal mass while facilitating use of skeletal mineral for metabolic homeostasis. Regulation of the mammalian skeleton, in this context, reflects practical adaptations to the needs for life on land that are related to ancestral developmental signals. This regulation includes central nervous system regulation that integrates bone turnover with overall metabolism. Recent work on skeletal development, in addition, demonstrates molecular mechanisms that cause developmental bone diseases.
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Affiliation(s)
- Harry C Blair
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Wang FS, Ko JY, Yeh DW, Ke HC, Wu HL. Modulation of Dickkopf-1 attenuates glucocorticoid induction of osteoblast apoptosis, adipocytic differentiation, and bone mass loss. Endocrinology 2008; 149:1793-801. [PMID: 18174290 DOI: 10.1210/en.2007-0910] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Long-term glucocorticoid treatment impairs the survival and bone formation of osteogenic cells, leading to bone mass loss. The Wnt inhibitor Dickkopf-1 (DKK1) acts as a potent bone-remodeling factor that mediates several types of skeletal disorders. Whereas excess glucocorticoid is known to disturb Wnt signaling in osteogenic cells, modulation of the skeletally deleterious effects of DKK1 to alleviate glucocorticoid induction of bone loss has not been tested. In this study, knockdown of DKK1 expression by end-capped phosphorothioate DKK1 antisense oligonucleotide (DKK1-AS) abrogated dexamethasone suppression of alkaline phosphatase activity and osteocalcin expression in MC3T3-E1 preosteoblasts. Exogenous DKK1-AS treatment alleviated dexamethasone suppression of mineral density, trabecular bone volume, osteoblast surface, and bone formation rate in bone tissue and ex vivo osteogenesis of primary bone-marrow mesenchymal cells. The DKK1-AS inhibited adipocyte volume in the marrow cavity of steroid-treated bone tissue. Immunohistochemical observation revealed that DKK1-AS abrogated dexamethasone-induced DKK1 expression and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling of osteoblasts adjacent to trabecular bone. Knocking down DKK1 abrogated dexamethasone-modulated expression of nuclear beta-catenin and phosphorylated Ser(473)-Akt and survival of osteoblasts and adipocytic differentiation of mesenchymal progenitor cell cultures. Taken together, knocking down DKK1 alleviated the deleterious effect of glucocorticoid on bone microstructure. The DKK1-AS treatment appeared to protect bone tissue by modulating beta-catenin and Akt-mediated survival as well as the osteogenic and adipogenic activities of glucocorticoid-stressed osteoprogenitor cells. Interference with the osteogenesis-inhibitory action of DKK1 has therapeutic potential for preventing glucocorticoid induction of osteopenia.
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Affiliation(s)
- Feng-Sheng Wang
- Department of Medical Research, Chang Gung Memorial Hospital-Kaohisung Medical Center, 123 Ta-Pei Road, Niao-Sung, Kaohsiung 833, Taiwan.
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Espina B, Liang M, Russell RGG, Hulley PA. Regulation of bim in glucocorticoid-mediated osteoblast apoptosis. J Cell Physiol 2008; 215:488-96. [PMID: 18064628 DOI: 10.1002/jcp.21335] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Osteoblasts undergo apoptosis both in vitro and in vivo in response to high dose glucocorticoid (GC) treatment. However, the molecular mechanisms remain elusive, hindering the prevention and treatment of this side-effect. Apoptosis was induced by dexamethasone (Dex) in murine MBA-15.4 osteoblasts within 24-48 h of treatment. We found dose- and time-dependent upregulation of Bim protein, a pro-apoptotic Bcl-2 family member, with highest levels at 24-48 h for 1 microM Dex. This was also observed in primary human bone marrow stromal cells. Bim is subjected to stringent transcriptional and post-translational regulation in osteoblasts. Bim mRNA was upregulated in response to 1 microM Dex; both cycloheximide and the GC receptor antagonist, RU486, prevented Dex-induction of Bim protein, indicating transcriptional regulation involving the GC receptor. The proteasome inhibitor, MG132, potently increased Bim protein levels. Bim was also upregulated in osteoblasts undergoing apoptosis in response to serum deprivation and matrix detachment. Gene silencing experiments show that short interference RNA (siRNA) specific for Bim or the downstream effector Bax both reduced apoptosis induced by Dex in osteoblastic cells. These findings suggest that Bim is a novel regulator of osteoblast apoptosis and may be a therapeutic target.
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Affiliation(s)
- B Espina
- The Botnar Research Centre, Oxford Institute of Musculoskeletal Sciences, Nuffield Department of Orthopaedic Surgery, Oxford, UK.
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45
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Abstract
UNLABELLED To study the role of the GR gene on BMD regulation in the Chinese, a sex-specific association study was performed. The results indicated that GR variation contributed to the extreme BMD variation in the Chinese. INTRODUCTION The glucocorticoid (GC) receptor (GR) gene is an important candidate gene for BMD regulation in GC-induced osteoporosis (GIO). However, no study has explored the genetic effects of the GR gene on BMD variation in the Chinese population. MATERIALS AND METHODS Our sample consisted of 800 unrelated subjects (400 women and 400 men) with extreme age-adjusted hip BMD Z-scores selected from a population composed of 1988 normal adult Chinese Han. Four single nucleotide polymorphisms (SNPs) in the GR gene were genotyped. Both single SNP and haplotype association analyses were conducted. RESULTS SNP rs1866388 (p(c) = 0.028) was found to be significantly associated with extreme BMD only in men. In both sexes, haplotypes involving rs1866388 and rs2918419 were found to have different frequency distributions in extremely low and high BMD groups (p(p) = 0.024, 0.001, and 0.002 in women and 0.002, 0.003, and 0.003 in men for window sizes of two, three, and four SNPs, respectively). Most shared haplotypes showed opposite effects between women and men. CONCLUSIONS For the first time, our study suggested the possible role of the GR gene on BMD regulation and sex specificity in the association of GR with extreme BMD in the Chinese.
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46
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Castañeda S, Calvo E, Largo R, González-González R, de la Piedra C, Díaz-Curiel M, Herrero-Beaumont G. Characterization of a new experimental model of osteoporosis in rabbits. J Bone Miner Metab 2008; 26:53-9. [PMID: 18095064 DOI: 10.1007/s00774-007-0797-1] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Accepted: 06/13/2007] [Indexed: 11/30/2022]
Abstract
To characterize an experimental model of osteoporosis in rabbits induced either by ovariectomy (OVX), glucocorticoids, or by a combination of both. Thirty-five rabbits were randomly allocated into five groups: bilateral OVX, daily methylprednisolone hemisuccinate (MPH) injections at a 1.5 mg/kg/day dose for 4 consecutive weeks (MPH group), or variable dose of MPH between 0.5 and 2 mg/kg/day in combination with OVX (OVX + MPH at low, medium, and high dose). Twenty-two animals were killed 6 weeks after OVX, and 13 were killed 16 weeks later. Dual-energy X-ray absorptiometry was obtained at baseline and 6 and 16 weeks after OVX. High-resolution magnetic resonance imaging (MRI) was carried out at 0 and 6 weeks after OVX. Glucose, total cholesterol, triglyceride, and oestradiol blood levels before and 16 weeks after OVX were determined. Bone mineral density (BMD) decreased significantly at lumbar spine in MPH and OVX + MPH medium-dose groups, and at global knee and subchondral bone of the knee in MPH, OVX + MPH low- and medium-dosage groups (P < 0.05). BMD variations in OVX rabbits were not significant in any of the three anatomical locations analyzed. BMD variation 16 weeks after OVX was significant at lumbar spine and global knee in the OVX + MPH medium-dose group and only at global knee in the OVX + MPH low-dose group (P < 0.05). MRI did not show bone or cartilage changes. Osteoporosis can be induced experimentally in rabbits through isolated MPH or by a combination of OVX and medium dose corticosteroid for 4 weeks. OVX alone was not sufficient to induce osteoporosis.
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Affiliation(s)
- Santos Castañeda
- Department of Rheumatology, Hospital de la Princesa, Universidad Autónoma, Madrid, Spain
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47
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Sharrow AC, Li Y, Micsenyi A, Griswold RD, Wells A, Monga SSP, Blair HC. Modulation of osteoblast gap junction connectivity by serum, TNFalpha, and TRAIL. Exp Cell Res 2007; 314:297-308. [PMID: 18022159 DOI: 10.1016/j.yexcr.2007.10.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 09/14/2007] [Accepted: 10/09/2007] [Indexed: 10/22/2022]
Abstract
We studied the effects of serum growth factors and of TNF family proteins on osteoblast gap junction connectivity. Serum starvation of human MG63 osteosarcoma cells or nontransformed osteoblasts decreased connexin43 protein. TNFalpha or TRAIL reduced connexin43 further. Serum starvation redistributed gap junctions but did not reduce intercellular diffusion. In contrast, TNFalpha or TRAIL reduced gap junctions on cell processes and decreased intercellular diffusion. Effects of TNFs on connexin43 were mediated by lysosomal proteolysis. Activating analogs of cAMP increased connexin43 protein, but did not block effects of serum starvation, TNFalpha, or TRAIL on connexin43 protein. Connexin43 and connectivity recovered overnight if stimuli were withdrawn. Surprisingly, connexin43 mRNA increased in serum starvation and with TNFalpha or TRAIL. Since beta-catenin is a binding partner of connexin43, when connexin43 is degraded, beta-catenin activation may contribute to a reflexive increase in connexin43 transcription. We conclude that osteoblast connectivity is regulated by a multifactorial system that maintains intercellular connections. Serum starvation, TNFalpha and TRAIL augmented connexin43 degradation and connexin43 transcription. Cell-cell communication was maintained in serum starvation, which may model response to acute injury, but was sensitive to TNFs. These inflammatory agents mediated selective, reversible removal of connexin43 from cell processes.
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Affiliation(s)
- Allison C Sharrow
- Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15243, USA
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Kawate K, Yajima H, Sugimoto K, Ono H, Ohmura T, Kobata Y, Murata K, Shigematsu K, Kawamura K, Kawahara I, Maegawa N, Tamai K, Takakura Y, Tamai S. Indications for free vascularized fibular grafting for the treatment of osteonecrosis of the femoral head. BMC Musculoskelet Disord 2007; 8:78. [PMID: 17686144 PMCID: PMC1988800 DOI: 10.1186/1471-2474-8-78] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Accepted: 08/08/2007] [Indexed: 11/10/2022] Open
Abstract
Background The present study aimed to determine the indications for free vascularized fibular grafting for the treatment of osteonecrosis of the femoral head. Methods Seventy-one hips (60 patients) were clinically followed for a minimum of 3 years. Average follow-up period was 7 years. Etiologies were alcohol abuse in 31 hips, steroid use in 27, idiopathic in 7 and trauma in 6. Preoperative staging of the necrotic lesion was done using the Steinberg's classification system. The outcomes of free vascularized fibular grafting were determined clinically using the Harris hip-scoring system, radiographically by determining progression, and survivorship by lack of conversion to total hip replacement. Results The average preoperative Harris hip score was 56 points and the average score at the latest follow-up examination was 78 points. Forty-seven hips (67%) were clinically rated good to excellent, 4 hips (6%) were rated fair, and 20 hips (28%) were rated poor. Thirty-six hips (51%) did not show radiographic progression while 35 hips (49%) did, and with an overall survivorship of 83% at 7 years. Steroid-induced osteonecrosis was significantly associated with poor scores and survival rate (68%). Preoperative collapse was significantly associated with poor scores, radiographic progression and poor survival rate (72%). A large extent of osteonecrosis greater than 300 degrees was significantly associated with poor scores, radiographic progression and poor survival rate (67%). There was no relationship between the distance from the tip of the grafted fibula to the subchondral bone of the femoral head and postoperative radiographic progression. Conclusion In conclusion, small osteonecrosis (less than 300 degrees of the femoral head) without preoperative collapse (Steinberg's stages I and II) is the major indication for free vascularized fibular grafting. Steroid-induced osteonecrosis is a relative contraindication. Large osteonecrosis (greater than 300 degrees) with severe preoperative collapse (greater than 3 mm) is a major contraindication. Hips with 2 negative factors such as severe preoperative collapse and a large extent of osteonecrosis, require hip replacements.
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Affiliation(s)
- Kenji Kawate
- Department of Orthopaedic Surgery, Nara Medical University, Japan
| | - Hiroshi Yajima
- Department of Orthopaedic Surgery, Nara Medical University, Japan
| | - Kazuya Sugimoto
- Department of Orthopaedic Surgery, Saiseikai Nara Hospital, Japan
| | - Hiroshi Ono
- Department of Orthopaedic Surgery, Kokuho Central Hospital, Japan
| | - Tetsuji Ohmura
- Department of Orthopaedic Surgery, Todaiji Seishien, Japan
| | - Yasunori Kobata
- Department of Orthopaedic Surgery, Nara Medical University, Japan
| | - Keiichi Murata
- Department of Orthopaedic Surgery, Nara Medical University, Japan
| | - Koji Shigematsu
- Department of Orthopaedic Surgery, Heisei Rehabilitation School, Japan
| | - Kenji Kawamura
- Department of Orthopaedic Surgery, Nara Medical University, Japan
| | - Ikuo Kawahara
- Department of Orthopaedic Surgery, Nara Medical University, Japan
| | - Naoki Maegawa
- Department of Orthopaedic Surgery, Nara Medical University, Japan
| | - Katsuya Tamai
- Department of Orthopaedic Surgery, Nara Medical University, Japan
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Chavassieux P, Seeman E, Delmas PD. Insights into material and structural basis of bone fragility from diseases associated with fractures: how determinants of the biomechanical properties of bone are compromised by disease. Endocr Rev 2007; 28:151-64. [PMID: 17200084 DOI: 10.1210/er.2006-0029] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Minimal trauma fractures in bone diseases are the result of bone fragility. Rather than considering bone fragility as being the result of a reduced amount of bone, we recognize that bone fragility is the result of changes in the material and structural properties of bone. A better understanding of the contribution of each component of the material composition and structure and how these interact to maintain whole bone strength is obtained by the study of metabolic bone diseases. Disorders of collagen (osteogenesis imperfecta and Paget's disease of bone), mineral content, composition and distribution (fluorosis and osteomalacia); diseases of high remodeling (postmenopausal osteoporosis, hyperparathyroidism, and hyperthyroidism) and low remodeling (osteopetrosis, pycnodysostosis); and other diseases (idiopathic male osteoporosis, corticosteroid-induced osteoporosis) produce abnormalities in the material composition and structure that lead to bone fragility. Observations in patients and in animal models provide insights on the biomechanical consequences of these illnesses and the nature of the qualities of bone that determine its strength.
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Affiliation(s)
- P Chavassieux
- Institut National de la Santé et de la Recherche Médicale Unit 831, Pavillon F, Hopital E. Herriot, 69437 Lyon Cedex 08, France
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50
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Abstract
Calcium transport and calcium signalling mechanisms in bone cells have, in many cases, been discovered by study of diseases with disordered bone metabolism. Calcium matrix deposition is driven primarily by phosphate production, and disorders in bone deposition include abnormalities in membrane phosphate transport such as in chondrocalcinosis, and defects in phosphate-producing enzymes such as in hypophosphatasia. Matrix removal is driven by acidification, which dissolves the mineral. Disorders in calcium removal from bone matrix by osteoclasts cause osteopetrosis. On the other hand, although bone is central to management of extracellular calcium, bone is not a major calcium sensing organ, although calcium sensing proteins are expressed in both osteoblasts and osteoclasts. Intracellular calcium signals are involved in secondary control including cellular motility and survival, but the relationship of these findings to specific diseases is not clear. Intracellular calcium signals may regulate the balance of cell survival versus proliferation or anabolic functional response as part of signalling cascades that integrate the response to primary signals via cell stretch, estrogen, tyrosine kinase, and tumor necrosis factor receptors.
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Affiliation(s)
- H C Blair
- Department of Pathology, University of Pittsburgh, PA 15261, USA
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