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Yildirim G, Bergamo ETP, Poudel SB, Ruff RR, Dixit M, Hu B, Mijares DQ, Witek L, Chlebek C, Harrison DE, Strong R, Miller RA, Ladiges W, Bromage TG, Rosen CJ, Yakar S. Long-term effects of canagliflozin treatment on the skeleton of aged UM-HET3 mice. GeroScience 2023; 45:1933-1951. [PMID: 37166526 PMCID: PMC10400751 DOI: 10.1007/s11357-023-00803-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 04/18/2023] [Indexed: 05/12/2023] Open
Abstract
Sodium glucose cotransporter-2 inhibitors (SGLT2is) promote urinary glucose excretion and decrease plasma glucose levels independent of insulin. Canagliflozin (CANA) is an SGLT2i, which is widely prescribed, to reduce cardiovascular complications, and as a second-line therapy after metformin in the treatment of type 2 diabetes mellitus. Despite the robust metabolic benefits, reductions in bone mineral density (BMD) and cortical fractures were reported for CANA-treated subjects. In collaboration with the National Institute on Aging (NIA)-sponsored Interventions Testing Program (ITP), we tested skeletal integrity of UM-HET3 mice fed control (137 mice) or CANA-containing diet (180 ppm, 156 mice) from 7 to 22 months of age. Micro-computed tomography (micro-CT) revealed that CANA treatment caused significant thinning of the femur mid-diaphyseal cortex in both male and female mice, did not affect trabecular bone architecture in the distal femur or the lumbar vertebra-5 in male mice, but was associated with thinning of the trabeculae at the distal femur in CANA-treated female mice. In male mice, CANA treatment is associated with significant reductions in cortical bone volumetric BMD by micro-CT, and by quantitative backscattered scanning electron microscopy. Raman microspectroscopy, taken at the femur mid-diaphyseal posterior cortex, showed significant reductions in the mineral/matrix ratio and an increased carbonate/phosphate ratio in CANA-treated male mice. These data were supported by thermogravimetric assay (TGA) showing significantly decreased mineral and increased carbonate content in CANA-treated male mice. Finally, the sintered remains of TGA were subjected to X-ray diffraction and showed significantly higher fraction of whitlockite, a calcium orthophosphate mineral, which has higher resorbability than hydroxyapatite. Overall, long-term CANA treatment compromised bone morphology and mineral composition of bones, which likely contribute to increased fracture risk seen with this drug.
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Affiliation(s)
- Gozde Yildirim
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Edmara T. P. Bergamo
- David B. Kriser Dental Center, Biomaterials Division, Department of Molecular Pathobiology, NYU College of Dentistry, New York, NY 10010-4086 USA
| | - Sher Bahadur Poudel
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Ryan R. Ruff
- David B. Kriser Dental Center, Department of Epidemiology and Health Promotion, New York University College of Dentistry, New York, NY 10010-4086 USA
| | - Manisha Dixit
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Bin Hu
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Dindo Q. Mijares
- David B. Kriser Dental Center, Biomaterials Division, Department of Molecular Pathobiology, NYU College of Dentistry, New York, NY 10010-4086 USA
| | - Lukasz Witek
- David B. Kriser Dental Center, Biomaterials Division, Department of Molecular Pathobiology, NYU College of Dentistry, New York, NY 10010-4086 USA
- Department of Biomedical Engineering, Tandon School of Engineering New York University, Brooklyn, NY 11201 USA
| | - Carolyn Chlebek
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, USA
| | | | - Randy Strong
- Geriatric Research, Education and Clinical Center and Research Service, South Texas Veterans Health Care System, San Antonio, TX USA
- Barshop Institute for Longevity and Aging Studies and Department of Pharmacology, The University of Texas Health Science Center, San Antonio, TX USA
| | - Richard A. Miller
- Department of Pathology and Geriatrics Center, University of Michigan, Ann Arbor, MI USA
| | - Warren Ladiges
- Department of Comparative Medicine, School of Medicine, University of Washington, Seattle, WA USA
| | - Timothy G. Bromage
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
| | - Clifford J. Rosen
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, USA
| | - Shoshana Yakar
- David B. Kriser Dental Center, Department of Molecular Pathobiology, New York University College of Dentistry, 345 East 24Th Street, New York, NY 10010-4086 USA
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Tang T, Landis W, Blouin S, Bertinetti L, Hartmann MA, Berzlanovich A, Weinkamer R, Wagermaier W, Fratzl P. Subcanalicular Nanochannel Volume Is Inversely Correlated With Calcium Content in Human Cortical Bone. J Bone Miner Res 2023; 38:313-325. [PMID: 36433915 DOI: 10.1002/jbmr.4753] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/10/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022]
Abstract
The spatial distribution of mineralization density is an important signature of bone growth and remodeling processes, and its alterations are often related to disease. The extracellular matrix of some vertebrate mineralized tissues is known to be perfused by a lacunocanalicular network (LCN), a fluid-filled unmineralized structure that harbors osteocytes and their fine processes and transports extracellular fluid and its constituents. The current report provides evidence for structural and compositional heterogeneity at an even smaller, subcanalicular scale. The work reveals an extensive unmineralized three-dimensional (3D) network of nanochannels (~30 nm in diameter) penetrating the mineralized extracellular matrix of human femoral cortical bone and encompassing a greater volume fraction and surface area than these same parameters of the canaliculi comprising the LCN. The present study combines high-resolution focused ion beam-scanning electron microscopy (FIB-SEM) to investigate bone ultrastructure in 3D with quantitative backscattered electron imaging (qBEI) to estimate local bone mineral content. The presence of nanochannels has been found to impact qBEI measurements fundamentally, such that volume percentage (vol%) of nanochannels correlates inversely with weight percentage (wt%) of calcium. This mathematical relationship between nanochannel vol% and calcium wt% suggests that the nanochannels could potentially provide space for ion and small molecule transport throughout the bone matrix. Collectively, these data propose a reinterpretation of qBEI measurements, accounting for nanochannel presence in human bone tissue in addition to collagen and mineral. Further, the results yield insight into bone mineralization processes at the nanometer scale and present the possibility for a potential role of the nanochannel system in permitting ion and small molecule diffusion throughout the extracellular matrix. Such a possible function could thereby lead to the sequestration or occlusion of the ions and small molecules within the extracellular matrix. © 2022 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)
- Tengteng Tang
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - William Landis
- Department of Preventive and Restorative Dental Sciences, University of California at San Francisco, San Francisco, CA, USA
| | - Stéphane Blouin
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med. Department Hanusch Hospital, Vienna, Austria
| | - Luca Bertinetti
- Center for Molecular Bioengineering, TU Dresden, Dresden, Germany
| | - Markus A Hartmann
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med. Department Hanusch Hospital, Vienna, Austria
| | | | - Richard Weinkamer
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Wolfgang Wagermaier
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Peter Fratzl
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
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Bone Measurements by Peripheral Quantitative Computed Tomography in Rodents. Methods Mol Biol 2019; 1914:533-558. [PMID: 30729485 DOI: 10.1007/978-1-4939-8997-3_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
Abstract
This chapter provides information for the in vivo use of peripheral quantitative computed tomography in rats and mice to determine bone density and cortical geometric data, including suggestions for study design, instrument setting, and data interpretation. This update also provides guidance for the use of pQCT to extract muscle and fat cross-sectional area information from the bone scans.
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Beresheim AC, Pfeiffer SK, Grynpas MD, Alblas A. Use of backscattered scanning electron microscopy to quantify the bone tissues of mid‐thoracic human ribs. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 168:262-278. [DOI: 10.1002/ajpa.23716] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 09/10/2018] [Accepted: 09/11/2018] [Indexed: 01/08/2023]
Affiliation(s)
- Amy C. Beresheim
- Department of AnthropologyUniversity of Toronto Toronto Ontario Canada
| | - Susan K. Pfeiffer
- Department of AnthropologyUniversity of Toronto Toronto Ontario Canada
- Department of ArchaeologyUniversity of Cape Town Rondebosch Cape Town South Africa
- Department of Anthropology and Center for Advanced Study of Human PaleobiologyGeorge Washington University Washington, D.C
| | - Marc D. Grynpas
- Department of Laboratory Medicine and Pathobiology and Institute for Biomaterials and Biomedical EngineeringUniversity of Toronto Toronto Ontario Canada
- Lunenfeld‐Tanenbaum Research Institute, Mount Sinai Hospital Toronto Ontario Canada
| | - Amanda Alblas
- Division of Anatomy and Histology, Department of Biomedical SciencesStellenbosch University Cape Town South Africa
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Rodriguez-Florez N, Garcia-Tunon E, Mukadam Q, Saiz E, Oldknow KJ, Farquharson C, Millán JL, Boyde A, Shefelbine SJ. An investigation of the mineral in ductile and brittle cortical mouse bone. J Bone Miner Res 2015; 30:786-95. [PMID: 25418329 PMCID: PMC4507744 DOI: 10.1002/jbmr.2414] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 11/07/2014] [Accepted: 11/20/2014] [Indexed: 12/28/2022]
Abstract
Bone is a strong and tough material composed of apatite mineral, organic matter, and water. Changes in composition and organization of these building blocks affect bone's mechanical integrity. Skeletal disorders often affect bone's mineral phase, either by variations in the collagen or directly altering mineralization. The aim of the current study was to explore the differences in the mineral of brittle and ductile cortical bone at the mineral (nm) and tissue (µm) levels using two mouse phenotypes. Osteogenesis imperfecta model, oim(-/-) , mice have a defect in the collagen, which leads to brittle bone; PHOSPHO1 mutants, Phospho1(-/-) , have ductile bone resulting from altered mineralization. Oim(-/-) and Phospho1(-/-) were compared with their respective wild-type controls. Femora were defatted and ground to powder to measure average mineral crystal size using X-ray diffraction (XRD) and to monitor the bulk mineral to matrix ratio via thermogravimetric analysis (TGA). XRD scans were run after TGA for phase identification to assess the fractions of hydroxyapatite and β-tricalcium phosphate. Tibiae were embedded to measure elastic properties with nanoindentation and the extent of mineralization with backscattered electron microscopy (BSE SEM). Results revealed that although both pathology models had extremely different whole-bone mechanics, they both had smaller apatite crystals, lower bulk mineral to matrix ratio, and showed more thermal conversion to β-tricalcium phosphate than their wild types, indicating deviations from stoichiometric hydroxyapatite in the original mineral. In contrast, the degree of mineralization of bone matrix was different for each strain: brittle oim(-/-) were hypermineralized, whereas ductile Phospho1(-/-) were hypomineralized. Despite differences in the mineralization, nanoscale alterations in the mineral were associated with reduced tissue elastic moduli in both pathologies. Results indicated that alterations from normal crystal size, composition, and structure are correlated with reduced mechanical integrity of bone.
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Bassett JHD, Boyde A, Zikmund T, Evans H, Croucher PI, Zhu X, Park JW, Cheng SY, Williams GR. Thyroid hormone receptor α mutation causes a severe and thyroxine-resistant skeletal dysplasia in female mice. Endocrinology 2014; 155:3699-712. [PMID: 24914936 PMCID: PMC4138578 DOI: 10.1210/en.2013-2156] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 04/11/2014] [Indexed: 02/03/2023]
Abstract
A new genetic disorder has been identified that results from mutation of THRA, encoding thyroid hormone receptor α1 (TRα1). Affected children have a high serum T3:T4 ratio and variable degrees of intellectual deficit and constipation but exhibit a consistently severe skeletal dysplasia. In an attempt to improve developmental delay and alleviate symptoms of hypothyroidism, patients are receiving varying doses and durations of T4 treatment, but responses have been inconsistent so far. Thra1(PV/+) mice express a similar potent dominant-negative mutant TRα1 to affected individuals, and thus represent an excellent disease model. We hypothesized that Thra1(PV/+) mice could be used to predict the skeletal outcome of human THRA mutations and determine whether prolonged treatment with a supraphysiological dose of T4 ameliorates the skeletal abnormalities. Adult female Thra1(PV/+) mice had short stature, grossly abnormal bone morphology but normal bone strength despite high bone mass. Although T4 treatment suppressed TSH secretion, it had no effect on skeletal maturation, linear growth, or bone mineralization, thus demonstrating profound tissue resistance to thyroid hormone. Despite this, prolonged T4 treatment abnormally increased bone stiffness and strength, suggesting the potential for detrimental consequences in the long term. Our studies establish that TRα1 has an essential role in the developing and adult skeleton and predict that patients with different THRA mutations will display variable responses to T4 treatment, which depend on the severity of the causative mutation.
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Affiliation(s)
- J H Duncan Bassett
- Department of Medicine (J.H.D.B., G.R.W.), Imperial College London, London W12 0NN, United Kingdom; Dental Physical Sciences, Oral Growth and Development (A.B.), Queen Mary University of London, London E1 4NS, United Kingdom; Laboratory of X-Ray Micro-Computed Tomography and Nano-Computed Tomography (T.Z.), Central European Institute of Technology, Brno University of Technology CZ-61600 Brno, Czech Republic; Sheffield Myeloma Research Team (H.E.), University of Sheffield, Sheffield S10 2RX, United Kingdom; Bone Biology Program (P.I.C.), Garvan Institute of Medical Research, Sydney NSW 2010, Australia; and Laboratory of Molecular Biology (X.Z., J.W.P., S-y.C.), National Cancer Institute, Bethesda, Maryland 20892
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Koehne T, Vettorazzi E, Küsters N, Lüneburg R, Kahl-Nieke B, Püschel K, Amling M, Busse B. Trends in trabecular architecture and bone mineral density distribution in 152 individuals aged 30-90 years. Bone 2014; 66:31-8. [PMID: 24859568 DOI: 10.1016/j.bone.2014.05.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 05/12/2014] [Accepted: 05/15/2014] [Indexed: 01/22/2023]
Abstract
The strength of trabecular bone depends on its microarchitecture and its tissue level properties. However, the interrelation between these two determinants of bone quality and their relation to age remain to be clarified. Iliac crest bone cores (n=152) from individuals aged 30-90 years were analyzed by quantitative backscattered electron imaging. Univariate and multivariate analyses were conducted to determine whether epidemiological parameters (age, sex or BMI), structural histomorphometrical variables (BV/TV, Tb.Th, Tb.N and Tb.Sp) and osteoid-related indices (OV/BV, OS/BS or O.Th) predict the degree of bone mineralization. While sex and BMI were not associated with bone mineralization, age was positively correlated with the most frequently occurring calcium concentrations (Ca peak), the percentage of highly mineralized bone areas (Ca high) and, in the case of adjusted covariates, also the mean calcium content (Ca mean). Bone volume fraction and trabecular thickness were both negatively correlated with Ca mean. However, trabecular thickness was additionally associated with Ca peak, Ca high as well as the amount of low mineralized bone (Ca low) and was the only structural parameter predicting bone mineralization independent of age. Furthermore, our analyses demonstrated that osteoid variables - within a normal range (<2% OV/BV) - were significantly associated with all mineralization parameters and represent the only predictor for the mineralization heterogeneity (Ca width). Taken together, we showed that elevated trabecular bone mineralization correlates with aging and bone loss. However, these associations are attributable to trabecular thinning that comes along with high bone mineralization due to the loss of low mineralized bone surfaces. Therefore, we demonstrated that the degree of areally resolved bone mineral is primarily associated with the amount of physiological osteoid present and the thickness of mineralized bone in trabeculae.
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Affiliation(s)
- Till Koehne
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Department of Orthodontics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Eik Vettorazzi
- Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Natalie Küsters
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rike Lüneburg
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Bärbel Kahl-Nieke
- Department of Orthodontics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Klaus Püschel
- Department of Legal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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Boutroy S, Walker MD, Liu XS, McMahon DJ, Liu G, Guo XE, Bilezikian JP. Lower cortical porosity and higher tissue mineral density in Chinese American versus white women. J Bone Miner Res 2014; 29:551-61. [PMID: 23913668 DOI: 10.1002/jbmr.2057] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 07/18/2013] [Accepted: 07/22/2013] [Indexed: 02/02/2023]
Abstract
Asian women have lower rates of hip and forearm fractures compared to other racial groups despite lower areal bone mineral density (aBMD). We have demonstrated microarchitectural differences, including greater cortical thickness (Ct.Th) and cortical volumetric BMD (Ct.BMD), in Chinese American versus white women. Yet it is not known whether greater Ct.BMD in Chinese American women is a result of greater tissue mineral density (TMD) or reduced cortical porosity (Ct.Po). Using an advanced segmentation algorithm based on high-resolution peripheral quantitative computed tomography (HR-pQCT) images, we tested the hypothesis that Chinese American women have better cortical skeletal integrity owing to lower Ct.Po and higher Ct.TMD compared with white women. A total of 78 Chinese American women (49 premenopausal and 29 postmenopausal) and 114 white women (46 premenopausal and 68 postmenopausal) were studied. Premenopausal Chinese American versus white women had greater Ct.Th, Ct.BMD, and Ct.TMD at both the radius and tibia, and decreased Ct.Po (p < 0.05). A similar pattern was observed between postmenopausal Chinese American and white women. As expected, postmenopausal versus premenopausal women had lower Ct.BMD at the radius and tibia in both races (p < 0.001). Ct.Po largely increased between premenopausal and postmenopausal women, whereas Ct.TMD decreased by 3% to 8% (p < 0.001) in both races. Age-related differences in Ct.Po and Ct.TMD did not differ by race. In summary, both reduced Ct.Po and greater Ct.TMD explain higher Ct.BMD in Chinese American versus white women. Thicker and preserved cortical bone structure in Chinese American women may contribute to greater resistance to fracture compared to white women.
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Affiliation(s)
- Stephanie Boutroy
- College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Paietta RC, Burger EL, Ferguson VL. Mineralization and collagen orientation throughout aging at the vertebral endplate in the human lumbar spine. J Struct Biol 2013; 184:310-20. [DOI: 10.1016/j.jsb.2013.08.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 08/22/2013] [Accepted: 08/24/2013] [Indexed: 11/27/2022]
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Pritchard JM, Papaioannou A, Tomowich C, Giangregorio LM, Atkinson SA, Beattie KA, Adachi JD, DeBeer J, Winemaker M, Avram V, Schwarcz HP. Bone mineralization is elevated and less heterogeneous in adults with type 2 diabetes and osteoarthritis compared to controls with osteoarthritis alone. Bone 2013; 54:76-82. [PMID: 23356988 PMCID: PMC5096932 DOI: 10.1016/j.bone.2013.01.032] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 01/08/2013] [Accepted: 01/15/2013] [Indexed: 01/22/2023]
Abstract
PURPOSE The purpose of this study was to determine whether trabecular bone mineralization differed in adults with type 2 diabetes compared to adults without type 2 diabetes. METHODS Proximal femur specimens were obtained following a total hip replacement procedure from men and women ≥65 years of age with and without type 2 diabetes. A scanning electron microscope was used for quantitative backscattered electron imaging (qBEI) analysis of trabecular bone samples from the femoral neck. Gray scale images (pixel size=5.6 μm(2)) were uploaded to ImageJ software and gray level (GL) values were converted to calcium concentrations (weight [wt] % calcium [Ca]) using data obtained with energy dispersive X-ray spectrometry. The following bone mineralization density distribution (BMDD) outcomes were collected: the weighted mean bone calcium concentration (CaMEAN), the most frequently occurring bone calcium concentration (CaPEAK) and mineralization heterogeneity (CaWIDTH). Differences between groups were assessed using the Student's t-test for normally distributed data and Mann-Whitney U-test for non-normally distributed data. An alpha value of <0.05 was considered significant. RESULTS Thirty-five Caucasian participants were recruited (mean [standard deviation, SD] age, 75.5 [6.5]years): 14 adults with type 2 diabetes (years since type 2 diabetes diagnosis, 13.5 [7.4]years) and 21 adults without type 2 diabetes. In the adults with type 2 diabetes, bone CaMEAN was 4.9% greater (20.36 [0.98]wt.% Ca versus 19.40 [1.07]wt.% Ca, p=0.015) and CaWIDTH was 9.4% lower (median [interquartile range] 3.55 [2.99-4.12]wt.% Ca versus 3.95 [0.71]wt.% Ca, p<0.001) compared to controls. There was no between-group difference in CaPEAK (21.12 [0.97]wt.% Ca for type 2 diabetes versus 20.44 [1.30]wt.% Ca for controls, p=0.121). CONCLUSION The combination of elevated mean calcium concentration in bone and lower mineralization heterogeneity in adults with type 2 diabetes may have deleterious effects on the biomechanical properties of bone. These microscopic alterations in bone mineralization, which may be mediated by suppressed bone remodeling, further elucidate higher fracture risk in adults with type 2 diabetes.
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Affiliation(s)
- J M Pritchard
- Faculty of Health Sciences, McMaster University, 1280 Main St West, Hamilton ON, Canada L8S 4K1.
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Bassett JHD, Logan JG, Boyde A, Cheung MS, Evans H, Croucher P, Sun XY, Xu S, Murata Y, Williams GR. Mice lacking the calcineurin inhibitor Rcan2 have an isolated defect of osteoblast function. Endocrinology 2012; 153:3537-48. [PMID: 22593270 DOI: 10.1210/en.2011-1814] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Calcineurin-nuclear factor of activated T cells signaling controls the differentiation and function of osteoclasts and osteoblasts, and regulator of calcineurin-2 (Rcan2) is a physiological inhibitor of this pathway. Rcan2 expression is regulated by T(3), which also has a central role in skeletal development and bone turnover. To investigate the role of Rcan2 in bone development and maintenance, we characterized Rcan2(-/-) mice and determined its skeletal expression in T(3) receptor (TR) knockout and thyroid-manipulated mice. Rcan2(-/-) mice had normal linear growth but displayed delayed intramembranous ossification, impaired cortical bone formation, and reduced bone mineral accrual during development as well as increased mineralization of adult bone. These abnormalities resulted from an isolated defect in osteoblast function and are similar to skeletal phenotypes of mice lacking the type 2 deiodinase thyroid hormone activating enzyme or with dominant-negative mutations of TRα, the predominant TR isoform in bone. Rcan2 mRNA was expressed in primary osteoclasts and osteoblasts, and its expression in bone was differentially regulated in TRα and TRβ knockout and thyroid-manipulated mice. However, in primary osteoblast cultures, T(3) treatment did not affect Rcan2 mRNA expression or nuclear factor of activated T cells c1 expression and phosphorylation. Overall, these studies establish that Rcan2 regulates osteoblast function and its expression in bone is regulated by thyroid status in vivo.
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Affiliation(s)
- J H Duncan Bassett
- Molecular Endocrinology Group, Department of Medicine, Imperial College London, Hammersmith Campus, London W12 0NN, United Kingdom
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Zoehrer R, Perilli E, Kuliwaba JS, Shapter JG, Fazzalari NL, Voelcker NH. Human bone material characterization: integrated imaging surface investigation of male fragility fractures. Osteoporos Int 2012; 23:1297-309. [PMID: 21695535 DOI: 10.1007/s00198-011-1688-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 05/27/2011] [Indexed: 02/06/2023]
Abstract
UNLABELLED The interrelation of calcium and phosphorus was evaluated as a function of bone material quality in femoral heads from male fragility fracture patients via surface analytical imaging as well as scanning microscopy techniques. A link between fragility fractures and increased calcium to phosphorus ratio was observed despite normal mineralization density distribution. INTRODUCTION Bone fragility in men has been recently recognized as a public health issue, but little attention has been devoted to bone material quality and the possible efficacy in fracture risk prevention. Clinical routine fracture risk estimations do not consider the quality of the mineralized matrix and the critical role played by the different chemical components that are present. This study uses a combination of different imaging and analytical techniques to gain insights into both the spatial distribution and the relationship of phosphorus and calcium in bone. METHODS X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry imaging techniques were used to investigate the relationship between calcium and phosphorus in un-embedded human femoral head specimens from fragility fracture patients and non-fracture age-matched controls. The inclusion of the bone mineral density distribution via backscattered scanning electron microscopy provides information about the mineralization status between the groups. RESULTS A link between fragility fracture and increased calcium and decreased phosphorus in the femoral head was observed despite normal mineralization density distribution. Results exhibited significantly increased calcium to phosphorus ratio in the fragility fracture group, whereas the non-fracture control group ratio was in agreement with the literature value of 1.66 M ratio in mature bone. CONCLUSIONS Our results highlight the potential importance of the relationship between calcium and phosphorus, especially in areas of new bone formation, when estimating fracture risk of the femoral head. The determination of calcium and phosphorus fractions in bone mineral density measurements may hold the key to better fracture risk assessment as well as more targeted therapies.
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Affiliation(s)
- R Zoehrer
- School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Bedford Park, Adelaide, SA 5042, Australia
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Gasser JA, Willnecker J. Bone measurements by peripheral quantitative computed tomography in rodents. Methods Mol Biol 2012; 816:477-498. [PMID: 22130945 DOI: 10.1007/978-1-61779-415-5_28] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This chapter provides information for the use of peripheral quantitative computed tomography in small animals, including suggestions for study design, instrument setting, and data interpretation.
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Affiliation(s)
- Jürg A Gasser
- Department of Musculoskeletal Diseases, Novartis Institutes for BioMedical Research, Basel, Switzerland.
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14
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Dias GJ, Cook RB, Mirhosseini M. Influence of food consistency on growth and morphology of the mandibular condyle. Clin Anat 2011; 24:590-8. [DOI: 10.1002/ca.21122] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Revised: 09/29/2010] [Accepted: 11/19/2010] [Indexed: 11/07/2022]
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15
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Power J, Poole KES, van Bezooijen R, Doube M, Caballero-Alías AM, Lowik C, Papapoulos S, Reeve J, Loveridge N. Sclerostin and the regulation of bone formation: Effects in hip osteoarthritis and femoral neck fracture. J Bone Miner Res 2010; 25:1867-76. [PMID: 20200987 DOI: 10.1002/jbmr.70] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Remodeling imbalance in the elderly femoral neck can result in thin cortices and porosity predisposing to hip fracture. Hip osteoarthritis protects against intracapsular hip fracture. By secreting sclerostin, osteocytes may inhibit Wnt signaling and reduce bone formation by osteoblasts. We hypothesised that differences in osteocytic sclerostin expression might account for differences in osteonal bone-formation activity between controls and subjects with hip fracture or hip osteoarthritis. Using specific antibody staining, we determined the osteocytic expression of sclerostin within osteons of the femoral neck cortex in bone removed from subjects undergoing surgery for hip osteoarthritis (hOA: 5 males, 5 females, 49 to 92 years of age) or hip fracture fixation (FNF: 5 males, 5 females, 73 to 87 years of age) and controls (C: 5 males, 6 females, 61 to 90 years of age). Sclerostin expression and distances of each osteocyte to the canal surface and cement line were assessed for all osteonal osteocytes in 636 unremodeled osteons chosen from fields ( approximately 0.5 mm in diameter) with at least one canal staining for alkaline phosphatase (ALP), a marker of bone formation. In adjacent sections, ALP staining was used to classify basic multicellular unit (BMUs) as quiescent or actively forming bone (ALP(+)). The areal densities of scl(-) and scl(+) osteocytes (number of cells per unit area) in the BMU were inversely correlated and were strong determinants of ALP status in the BMU. In controls and hip fracture patients only, sclerostin-negative osteocytes were closer to osteonal surfaces than positively stained cells. Osteon maturity (progress to closure) was strongly associated with the proportion of osteonal osteocytes expressing sclerostin, and sclerostin expression was the chief determinant of ALP status. hOA patients had 18% fewer osteocytes per unit bone area than controls, fewer osteocytes expressed sclerostin on average than in controls, but wide variation was seen between subjects. Thus, in most hOA patients, there was increased osteonal ALP staining and reduced sclerostin staining of osteocytes. In FNF patients, newly forming osteons were similar in this respect to hOA osteons, but with closure, there was a much sharper reduction in ALP staining that was only partly accounted for by the increased proportions of osteonal osteocytes staining positive for sclerostin. There was no evidence for a greater effect on ALP expression by osteocytes near the osteonal canal. In line with data from blocking antibody experiments, osteonal sclerostin appears to be a strong determinant of whether osteoblasts actively produce bone. In hOA, reduced sclerostin expression likely mediates increased osteoblastic activity in the intracapsular cortex. In FNF, full osteonal closure is postponed, with increased porosity, in part because the proportion of osteocytes expressing sclerostin increases sharply with osteonal maturation.
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Affiliation(s)
- Jon Power
- Bone Research Division, Department of Medicine, University of Cambridge, Cambridge, UK
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Kalichman L, Hernández-Molina G. Hand Osteoarthritis: An Epidemiological Perspective. Semin Arthritis Rheum 2010; 39:465-76. [DOI: 10.1016/j.semarthrit.2009.03.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 02/19/2009] [Accepted: 03/16/2009] [Indexed: 10/20/2022]
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Anumula S, Wehrli SL, Magland J, Wright AC, Wehrli FW. Ultra-short echo-time MRI detects changes in bone mineralization and water content in OVX rat bone in response to alendronate treatment. Bone 2010; 46:1391-9. [PMID: 20096815 PMCID: PMC2854263 DOI: 10.1016/j.bone.2010.01.372] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 01/06/2010] [Accepted: 01/13/2010] [Indexed: 01/16/2023]
Abstract
In this work we hypothesize that bisphosphonate treatment following ovariectomy manifests in increased phosphorus and decreased water concentration, both quantifiable nondestructively with ultra-short echo-time (UTE) (31)P and (1)H-MRI techniques. We evaluated this hypothesis in ovariectomized (OVX) rats undergoing treatment with two regimens of alendronate. Sixty female four-month-old rats were divided into four groups of 15 animals each: ovariectomized (OVX), OVX treatment groups ALN1 and ALN2, receiving 5 microg/kg/day and 25 microg/kg/day of alendronate, and a sham-operated group (NO) serving as control. Treatment, starting 1 week post-surgery, lasted for 50 days at which time animals were sacrificed. Whole bones from the left and right femora were extracted from all the animals. (31)P and (1)H water concentration were measured by UTE MRI at 162 and 400 MHz in the femoral shaft and the results compared with other measures of mineral and matrix properties obtained by (31)P solution NMR, CT density, ash weight, and water measured by dehydration. Mechanical parameters (elastic modulus, EM, and ultimate strength, US) were obtained by three-point bending. The following quantities were lower in OVX relative to NO: phosphorus concentration measured by (31)P-MRI (-8%; 11.4+/-0.9 vs. 12.4+/-0.8%, p<0.005), (31)P-NMR (-4%; 12.8+/-0.4 vs. 13.3+/-0.8 %, p<0.05) and micro-CT density (-2.5%; 1316+/-34 vs. 1349+/-32 mg/cm(3), p=0.005). In contrast, water concentration by (1)H-MRI was elevated in OVX relative to NO (+6%; 15.5+/-1.7 vs. 14.6+/-1.4 %, p<0.05). Alendronate treatment increased phosphorus concentration and decreased water concentration in a dose-dependent manner, the higher dose yielding significant changes relative to values found in OVX animals: (31)P-MRI (+14%; p<0.0001), (31)P-NMR (+9%; p<0.0001), ash content (+1.5%; p<0.005), micro-CT mineralization density (+2.8%; p<0.05), and (1)H-MRI, (-19%, p<0.0001). The higher dose raised phosphorus concentration above and water concentration below NO levels: (31)P-MRI (+6%; p<0.05), (31)P-NMR (+5%; p=0.01), ash content (+1.5%; p=0.005), (1)H-MRI (-14%; p<0.0001), and drying water (-10%; p<0.0005). Finally, the group means of phosphorus concentration were positively correlated with EM and US (R(2)> or =0.98, p<0.001 to p<0.05) even though the pooled data from individual animals were not. The results highlight the implications of estrogen depletion and bisphosphonate treatment on mineral composition and mechanical properties and the potential of solid-state MR imaging to detect these changes in situ in an animal model of rat ovariectomy.
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Affiliation(s)
- SeshaSailaja Anumula
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, USA
| | | | - Jeremy Magland
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, USA
| | - Alexander C. Wright
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, USA
| | - Felix W. Wehrli
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, USA
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Sánchez-Sabaté E, Alvarez L, Gil-Garay E, Munuera L, Vilaboa N. Identification of differentially expressed genes in trabecular bone from the iliac crest of osteoarthritic patients. Osteoarthritis Cartilage 2009; 17:1106-14. [PMID: 19303468 DOI: 10.1016/j.joca.2009.01.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2008] [Revised: 01/27/2009] [Accepted: 01/30/2009] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Osteoarthritis (OA) is clinically characterized by degeneration of the joints and has been traditionally considered a primary disorder of articular cartilage, with secondary changes in the subchondral bone. The increased bone mass and generalized changes in bone quality observed in osteoarthritic patients suggest that OA may be a primary systemic bone disorder with secondary articular cartilage damage. The iliac crest is a skeletal site distant from the affected joint, with a minimal load-bearing function. To provide evidence that OA is a systemic disorder, we searched for differentially expressed genes in the iliac crest bone of patients suffering from hip OA. MATERIAL AND METHODS Gene expression levels between bone samples collected at surgery from the iliac crest of patients undergoing total hip arthroplasty for primary OA and younger donors, who were undergoing spinal arthrodesis, were investigated by means of oligonucleotide microarrays. To verify data detected by microarrays technology, Real Time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) assays were performed with specimens from osteoarthritic patients and donors, as well as from elderly donors who were undergoing arthroplasty for subcapital femoral neck fracture. RESULTS The microarray analysis surveyed 8327 genes and identified 83 whose expression levels differed at least 1.5-fold in the OA group (P<0.005). Comparisons between Real Time RT-PCR data from OA and the two donor groups indicated differential expression of genes involved in bone cell functions in the group of OA patients. The genes identified, including CCL2, FOS, PRSS11, DVL2, AKT1, CA2, BMP6, OMD, MMP2, TGFBR3, FLT1, BMP1 and TNFRS11B, have known roles in osteoblast or osteoclast activities. CONCLUSIONS The data from this study identify a set of genes, closely related to bone cell functions, in which differential regulation in osteoarthritic bone distant from the diseased subchondral bone might underlie the etiopathogenesis of OA as a generalized bone disease.
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Affiliation(s)
- E Sánchez-Sabaté
- Unidad de Investigación, Hospital Universitario La Paz, Paseo de la Castellana 261, Madrid 28046, Spain
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19
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Erisken C, Kalyon DM, Wang H. Functionally graded electrospun polycaprolactone and β-tricalcium phosphate nanocomposites for tissue engineering applications. Biomaterials 2008; 29:4065-73. [DOI: 10.1016/j.biomaterials.2008.06.022] [Citation(s) in RCA: 219] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Accepted: 06/11/2008] [Indexed: 10/21/2022]
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20
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Techawiboonwong A, Song HK, Leonard MB, Wehrli FW. Cortical bone water: in vivo quantification with ultrashort echo-time MR imaging. Radiology 2008; 248:824-33. [PMID: 18632530 DOI: 10.1148/radiol.2482071995] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE To develop and evaluate a method based on ultrashort echo-time radial magnetic resonance (MR) imaging to quantify bone water (BW) concentration as a new metric of bone quality in human cortical bone in vivo. MATERIALS AND METHODS Human subject studies were institutional review board approved and HIPAA compliant; informed consent was obtained. Cortical BW concentration was determined with custom-designed MR imaging sequences at 3.0 T and was validated in sheep and human cortical bone by using exchange of native water with deuterium oxide (D(2)O). The submillisecond T2* of BW requires correction for relaxation losses during the radiofrequency pulse. BW was measured at the tibial midshaft in healthy pre- and postmenopausal women (mean age, 34.6 and 69.4 years, respectively; n = 5 in each group) and in patients receiving maintenance hemodialysis (mean age, 51.8 years; n = 6) and was compared with bone mineral density (BMD) at the same site at peripheral quantitative computed tomography, as well as with BMD of the lumbar spine and hip at dual x-ray absorptiometry. Data were analyzed by using the Pearson correlation coefficient and two-sided t tests as appropriate. RESULTS Excellent agreement was obtained ex vivo between the water displaced by using D(2)O exchange and water measured with respect to a reference sample (r(2) = 0.99, P < .001). In vivo, BW in the postmenopausal group was greater by 65% (28.7% +/- 1.3 [standard deviation] vs 17.4% +/- 2.2, P < .001) than in the premenopausal group, and patients with renal osteodystrophy had higher BW (41.4% +/- 9.6) than the premenopausal group by 135% (P < .001) and the postmenopausal group by 43% (P = .02). BMD showed an opposite behavior, with much smaller group differences. Because the majority of BW is in the pore system of cortical bone, this parameter provides a surrogate measure for cortical porosity. CONCLUSION A new MR imaging-based method for quantifying BW noninvasively has been demonstrated.
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Affiliation(s)
- Aranee Techawiboonwong
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce St, 1 Founders, MRI Education Center, Philadelphia, PA 19104, USA
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21
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Roschger P, Paschalis EP, Fratzl P, Klaushofer K. Bone mineralization density distribution in health and disease. Bone 2008; 42:456-66. [PMID: 18096457 DOI: 10.1016/j.bone.2007.10.021] [Citation(s) in RCA: 435] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Accepted: 10/28/2007] [Indexed: 01/15/2023]
Abstract
Human cortical and trabecular bones are formed by individual osteons and bone packets, respectively, which are produced at different time points during the (re)modeling cycle by the coupled activity of bone cells. This leads to a heterogeneously mineralized bone material with a characteristic bone mineralization density distribution (BMDD) reflecting bone turnover, mineralization kinetics and average bone matrix age. In contrast to BMD, which is an estimate of the total amount of mineral in a scanned area of whole bone, BMDD describes the local mineral content of the bone matrix throughout the sample. Moreover, the mineral content of the bone matrix is playing a pivotal role in tuning its stiffness, strength and toughness. BMDD of healthy individuals shows a remarkably small biological variance suggesting the existence of an evolutionary optimum with respect to its biomechanical performance. Hence, any deviations from normal BMDD due to either disease and/or treatment might be of significant biological and clinical relevance. The development of appropriate methods to sensitively measure the BMDD in bone biopsies led to numerous applications of BMDD in the evaluation of diagnosis and treatment of bone diseases, while advancing the understanding of the bone material, concomitantly. For example, transiliacal bone biopsies of postmenopausal osteoporotic women were found to have mostly lower mineralization densities than normal, which were partly associated by an increase of bone turnover, but also caused by calcium and Vit-D deficiency. Antiresorptive therapy causes an increase of degree and homogeneity of mineralization within three years of treatment, while normal mineralization levels are not exceeded. In contrast, anabolic therapy like PTH decreases the degree and homogeneity of matrix mineralization, at least transiently. Osteogenesis imperfecta is generally associated with increased matrix mineralization contributing to the brittleness of bone in this disease, though bone turnover is usually increased suggesting an alteration in the mineralization kinetics. Furthermore, BMDD measurements combined with other scanning techniques like nanoindentation, Fourier transform infrared spectroscopy and small angle X-ray scattering can provide important insights into the structure-function relation of the bone matrix, and ultimately a better prediction of fracture risk in diseases, and after treatment.
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Affiliation(s)
- P Roschger
- 4th Medical Department, Hanusch Hospital, Heinrich Collin Street 30, A-1140, Vienna, Austria
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22
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Anumula S, Magland J, Wehrli SL, Ong H, Song HK, Wehrli FW. Multi-modality study of the compositional and mechanical implications of hypomineralization in a rabbit model of osteomalacia. Bone 2008; 42:405-13. [PMID: 18053788 PMCID: PMC2259120 DOI: 10.1016/j.bone.2007.10.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Revised: 10/09/2007] [Accepted: 10/17/2007] [Indexed: 10/22/2022]
Abstract
Osteomalacia is characterized by hypomineralization of the bone associated with increased water content. In this work we evaluate the hypotheses that 1) 3D solid-state magnetic resonance imaging (MRI) of (31)P (SSI-PH) and (1)H (SSI-WATER) of cortical bone can quantify the key characteristics of osteomalacia induced by low-phosphate diet; and 2) return to normophosphatemic diet (NO) results in recovery of these indices to normal levels. Twenty female five-week old rabbits were divided into four groups. Five animals were fed a normal diet for 8 weeks (NOI); five a hypophosphatemic diet (0.09%) for the same period to induce osteomalacia (HYI). To examine the effect of recovery from hypophosphatemia an additional five animals received a hypophosphatemic diet for 8 weeks, after which they were returned to a normal diet for 6 weeks (HYII). Finally, five animals received a normal diet for the entire 14 weeks (NOII). The NOI and HYI animals were sacrificed after 8 weeks, the NOII and HYII groups after 14 weeks. Cortical bone was extracted from the left and right tibiae of all the animals. Water content was measured by SSI-WATER and by a previously reported spectroscopic proton-deuteron nuclear magnetic resonance (NMR) exchange technique (NMR-WATER), phosphorus content by SSI-PH. All MRI and NMR experiments were performed on a 9.4 T spectroscopy/micro-imaging system. Degree of mineralization of bone (DMB) was measured by micro-CT and elastic modulus and ultimate strength by 3-point bending. The following parameters were lower in the hypophosphatemic group: phosphorus content measured by SSI-PH (9.5+/-0.4 versus 11.1+/-0.3 wt.%, p<0.0001), ash content (63.9+/-1.7 versus 65.4+/-1.1 wt.%, p=0.05), ultimate strength, (96.3+/-16.0 versus 130.7+/-6.4 N/mm(2), p=0.001), and DMB (1115+/-28 versus 1176+/-24 mg/cm(3), p=0.003); SSI-WATER: 16.1+/-1.5 versus 14.4+/-1.1 wt.%, p=0.04; NMR-WATER: 19.0+/-0.6 versus 17.4+/-1.2 wt.%, p=0.01. Return to a normophosphatemic diet reduced or eliminated these differences (SSI-PH: 9.5+/-0.9 versus 10.6+/-0.8 wt.%, p=0.04; DMB: 1124+/-31 versus 1137+/-10 mg/cm(3), p=0.2; US: 95.6+/-18.6 versus 103.9+/-7.5 N/mm(2), p=0.2; SSI-WATER: 12.4+/-0.6 versus 12.2+/-0.3 wt.%, p=0.3) indicating recovery of the mineral density close to normal levels. Phosphorus content measured by SSI-PH was significantly correlated with DMB measured by micro-CT (r(2)=0.47, p=0.001) as well as with ultimate strength (r(2)=0.54, p=0.0004). The results show that the methods presented have potential for in situ assessment of mineralization and water, both critical to the bone's mechanical behavior.
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Affiliation(s)
- SeshaSailaja. Anumula
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, USA,
| | - Jeremy Magland
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, USA,
| | | | - Henry Ong
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, USA,
| | - Hee Kwon Song
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, USA,
| | - Felix W. Wehrli
- Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, USA,
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SUTTON-SMITH P, BEARD H, FAZZALARI N. Quantitative backscattered electron imaging of bone in proximal femur fragility fracture and medical illness. J Microsc 2008; 229:60-6. [DOI: 10.1111/j.1365-2818.2007.01867.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ebacher V, Tang C, McKay H, Oxland TR, Guy P, Wang R. Strain redistribution and cracking behavior of human bone during bending. Bone 2007; 40:1265-75. [PMID: 17317352 DOI: 10.1016/j.bone.2006.12.065] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Revised: 11/19/2006] [Accepted: 12/04/2006] [Indexed: 11/24/2022]
Abstract
Long bones often fail due to bending loads. Understanding the fracture process during bending is of great importance to the prevention and treatment of bone fractures. In this study, we investigated the origin of long bone's bending strength through the study of the dynamic strain redistribution happening during the post-yield stage of deformation and its relation to microdamage at the microstructural level. This was accomplished by comparing the behaviors of human long bones with standard cortical bone specimens in terms of strain redistribution, Poisson's ratios, microdamage morphologies, and macro-scale fracture patterns. It was found that human tibia failure in bending was very similar to that of standard beam cortical bone specimens with respect to the four previous aspects. Also, the examination of bone's Poisson's ratio indicated very different inelastic deformation mechanisms under tension and compression: bone volume expanded in tension but was nearly conserved in compression. Finally, as a result of strain redistribution, bone's bending strength mainly depended on its compressive strength, which was significantly influenced by the osteonal "porous" microstructure of human bone as compared to its tensile behavior. Thus, we concluded that bone microstructure at the Haversian system level plays an important role in bone deformation and fracture.
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Affiliation(s)
- Vincent Ebacher
- Department of Materials Engineering, University of British Columbia, Vancouver, BC, Canada
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25
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Sone T, Imai Y, Joo YI, Onodera S, Tomomitsu T, Fukunaga M. Side-to-side differences in cortical bone mineral density of tibiae in young male athletes. Bone 2006; 38:708-13. [PMID: 16289987 DOI: 10.1016/j.bone.2005.10.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Revised: 08/20/2005] [Accepted: 10/07/2005] [Indexed: 10/25/2022]
Abstract
The importance of physical activity in the development and maintenance of bone mineral density (BMD) is widely accepted. However, the effects on cortical BMD have not been clarified in detail. The present study examined bilateral asymmetries in cortical BMD of the tibia using peripheral quantitative computed tomography. Subjects comprised 37 young male athletes and 57 controls (age range, 18-28 years). BMD and geometrical indices were determined in bilateral tibiae. Cortical and trabecular BMD were calculated at the diaphysis and distal metaphysis, respectively. Cortical width, periosteal cross-sectional area, and cross-sectional moment of inertia were calculated using tomographic data of the tibial diaphysis. In athletes, the non-dominant leg showed greater cortical BMD than the dominant leg (mean difference, 5.42%; P < 0.0001). Cortical width and moment of inertia were also greater in the non-dominant leg. Periosteal area displayed no significant difference between legs. The control group exhibited similar results except for cortical BMD. No differences in trabecular BMD were noted between legs in either athletes or controls. These results implies the existence of mechanisms for the mechanical adaptation of cortical BMD. Dominant leg is used for mobility or manipulation whereas the non-dominant leg contributes to support the actions of the dominant leg. Loading differences in bilateral legs in young athletes might affect the remodeling rate leading to the side-to-side differences in cortical BMD.
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Affiliation(s)
- Teruki Sone
- Department of Nuclear Medicine, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan.
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26
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Regauer M, Jürgens P, Budenhofer U, Hartstock M, Böcker W, Bürklein D, Mutschler W, Sader R, Schieker M. Quantitative scanning acoustic microscopy compared to microradiography for assessment of new bone formation. Bone 2006; 38:564-70. [PMID: 16253577 DOI: 10.1016/j.bone.2005.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2005] [Revised: 09/08/2005] [Accepted: 09/14/2005] [Indexed: 11/21/2022]
Abstract
Recently, it has been shown that quantitative scanning acoustic microscopy (SAM) is a powerful tool to image the acoustic impedance of even inhomogeneous materials like bone. Therefore, the aim of our study was to compare SAM to conventional microradiography with respect to histomorphometrical assessment of undecalcified sections of newly formed bone. Forty specimens were harvested 12 weeks after implantation of either autogenous cancellous bone graft or 5.0 mg of Osteogenic Protein-1 (BMP-7) in a critical-sized defect model in sheep. Undecalcified transverse bone sections of 500 microm thickness were investigated with conventional microradiography and SAM. Linear regression analysis was carried out to compare the measurements of the area of new bone formation within the defect sites. Both methods allowed for good discrimination between newly formed bone and cortical bone at the edges of the former defect. Images obtained with SAM revealed a better resolution and sharpness compared to that of microradiographs since SAM imaging unlike microradiography does not depend on the thickness of bone sections. The results of quantitative histomorphometric analysis obtained by both methods showed no significant differences, and it was possible to predict 90% of the variability of each method (coefficient of determination r2 = 0.90; P < 0.0001). In conclusion, SAM offers comparable quantitative histomorphometric information with a better spatial resolution than conventional microradiography. Thus, SAM is a promising new micro-visualizing technique for basic bone research.
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Affiliation(s)
- Markus Regauer
- Experimental Surgery and Regenerative Medicine, Department of Surgery, University of Munich (LMU), Nussbaumstrasse 20, D-80336 München, Germany
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Abstract
Plantar fasciitis is a musculoskeletal disorder primarily affecting the fascial enthesis. Although poorly understood, the development of plantar fasciitis is thought to have a mechanical origin. In particular, pes planus foot types and lower-limb biomechanics that result in a lowered medial longitudinal arch are thought to create excessive tensile strain within the fascia, producing microscopic tears and chronic inflammation. However, contrary to clinical doctrine, histological evidence does not support this concept, with inflammation rarely observed in chronic plantar fasciitis. Similarly, scientific support for the role of arch mechanics in the development of plantar fasciitis is equivocal, despite an abundance of anecdotal evidence indicating a causal link between arch function and heel pain. This may, in part, reflect the difficulty in measuring arch mechanics in vivo. However, it may also indicate that tensile failure is not a predominant feature in the pathomechanics of plantar fasciitis. Alternative mechanisms including 'stress-shielding', vascular and metabolic disturbances, the formation of free radicals, hyperthermia and genetic factors have also been linked to degenerative change in connective tissues. Further research is needed to ascertain the importance of such factors in the development of plantar fasciitis.
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Affiliation(s)
- Scott C Wearing
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland, Australia.
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28
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Bloebaum RD, Holmes JL, Skedros JG. Mineral content changes in bone associated with damage induced by the electron beam. SCANNING 2005; 27:240-8. [PMID: 16268176 DOI: 10.1002/sca.4950270504] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Energy-dispersive x-ray (EDX) spectroscopy and backscattered electron (BSE) imaging are finding increased use for determining mineral content in microscopic regions of bone. Electron beam bombardment, however, can damage the tissue, leading to erroneous interpretations of mineral content. We performed elemental (EDX) and mineral content (BSE) analyses on bone tissue in order to quantify observable deleterious effects in the context of (1) prolonged scanning time, (2) scan versus point (spot) mode, (3) low versus high magnification, and (4) embedding in poly-methylmethacrylate (PMMA). Undemineralized cortical bone specimens from adult human femora were examined in three groups: 200x embedded, 200x unembedded, and 1000x embedded. Coupled BSE/EDX analyses were conducted five consecutive times, with no location analyzed more than five times. Variation in the relative proportions of calcium (Ca), phosphorous (P), and carbon (C) were measured using EDX spectroscopy, and mineral content variations were inferred from changes in mean gray levels ("atomic number contrast") in BSE images captured at 20 keV. In point mode at 200x, the embedded specimens exhibited a significant increase in Ca by the second measurement (7.2%, p < 0.05); in scan mode, a small and statistically nonsignificant increase (1.0%) was seen by the second measurement. Changes in P were similar, although the increases were less. The apparent increases in Ca and P likely result from decreases in C: -3.2% (p < 0.05) in point mode and -0.3% in scan mode by the second measurement. Analysis of unembedded specimens showed similar results. In contrast to embedded specimens at 200x, 1000x data showed significantly larger variations in the proportions of Ca, P, and C by the second or third measurement in scan and point mode. At both magnifications, BSE image gray level values increased (suggesting increased mineral content) by the second measurement, with increases up to 23% in point mode. These results show that mineral content measurements can be reliable when using coupled BSE/EDX analyses in PMMA-embedded bone if lower magnifications are used in scan mode and if prolonged exposure to the electron beam is avoided. When point mode is used to analyze minute regions, adjustments in accelerating voltages and probe current may be required to minimize damage.
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Affiliation(s)
- Roy D Bloebaum
- Bone and Joint Research Laboratory, Department of Veterans Affairs Medical Center, Salt Lake City Health Care System, Salt Lake City, UT 84148-9998, USA.
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Mkukuma LD, Imrie CT, Skakle JMS, Hukins DWL, Aspden RM. Thermal stability and structure of cancellous bone mineral from the femoral head of patients with osteoarthritis or osteoporosis. Ann Rheum Dis 2005; 64:222-5. [PMID: 15647430 PMCID: PMC1755354 DOI: 10.1136/ard.2004.021329] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Cancellous bone from patients with osteoarthritis (OA) has been reported to be undermineralised and that from patients with osteoporosis (OP) is more liable to fracture. Changes in the mineral component might be implicated in these processes. OBJECTIVES To investigate the thermal stability and the mineral structure of cancellous bone from femoral heads of patients with either OA or OP. METHODS Powdered bone was prepared from femoral heads of patients with either OA or OP and a control group. Composition and thermal stability were determined using a thermogravimetric analyser coupled to a mass spectrometer. Unit cell dimensions and the crystallite size of the mineral were measured using x ray diffraction. RESULTS Thermal stability of the bone matrix, or of the mineral phase alone, was little altered by disease, though OA bone contained less mineral than OP or control bone. In all three groups, x ray diffraction showed that the mineral unit cell dimensions and crystallite sizes were the same. The mean carbonate content in the mineral from all three groups was between 7.2 and 7.6% and is suggested to be located in both the A site (that is, substituting for hydroxyl groups), and the B site (that is, substituting for phosphate groups). CONCLUSIONS These results confirm that there is a lower mass fraction of mineral in OA bone, and indicate that the nature of the mineral is not a factor in either disease process.
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Affiliation(s)
- L D Mkukuma
- Department of Orthopaedic Surgery, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
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30
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Gentzsch C, Pueschel K, Deuretzbacher G, Delling G, Kaiser E. First inventory of resorption lacunae on rods and plates of trabecular bone as observed by scanning electron microscopy. Calcif Tissue Int 2005; 76:154-62. [PMID: 15549635 DOI: 10.1007/s00223-004-0212-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Accepted: 07/29/2004] [Indexed: 11/30/2022]
Abstract
In the present study a novel systematic distribution scheme of resorption lacunae (RL) was applied using scanning electron microscopy. RL, classified as either reticulate patch resorption lacunae (RPR) or as longitudinally extended resorption lacunae (LER) [11, were analyzed and quantified according to their localizations on rods (middle, nodes or both) and plates (central or peripheral) in standardized segments from the femoral head of 24 Caucasian subjects without bone disease. Age and gender variations were explored. No clear gender-related distribution pattern could be detected on plates. On rods of males, however, the distribution of RL tended to be higher at the nodes, but seemed to be more prevalent in the middle or extended from the middle to the nodes of rods in females. Certain other non-conclusive tendencies in relation to age, gender, type of RL and localization were observed.
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Affiliation(s)
- C Gentzsch
- Institute of Bone Pathology/Center of Biomechanics, University Hospital Eppendorf, Hamburg, Germany
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31
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Loveridge N, Power J, Reeve J, Boyde A. Bone mineralization density and femoral neck fragility. Bone 2004; 35:929-41. [PMID: 15454100 DOI: 10.1016/j.bone.2004.05.025] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2003] [Revised: 05/04/2004] [Accepted: 05/19/2004] [Indexed: 11/28/2022]
Abstract
The traditional view of osteoporotic fractures is that they result from a reduction in bone mass combined with alterations in the micro-architecture. Apart from the effects of bone remodeling, the material properties of the remaining bone are thought to be unaffected. To test this, we compared the degree of matrix mineralization in femoral neck biopsies taken from cases of intracapsular hip fracture with age- and sex-matched postmortem controls. Whole femoral neck biopsies from seven female hip fracture cases (72-90 years) and nine controls (68-94 years) were embedded in methylmethacrylate, and sections stained with Solochrome Cyanin R for analysis of osteoid. The blocks were then diamond micro-milled, carbon coated, and analyzed for the degree of matrix mineralization using halogenated dimethacrylate standards for quantitative backscattered electron (qBSE) imaging (20 kV, entire block face, sampling interval 5 microm). The BSE gray scale was adjusted such that 0 corresponds to an electron backscattering coefficient of 0.1159 (approximately 1.70 g/ml) and 255-0.1519 (approximately 2.18 g/ml). Remodeling and mineralization data were analyzed for both the whole biopsy face and on a regional (anterior; inferior, posterior, or superior) basis. Over the whole biopsy, the level of mineralization was lower in the cases than the postmortem controls (-2.8%, P < 0.05). In both cases and controls, cortical mineralization was higher in the inferior (compressive) region compared with superior (tensile) region (P < 0.05). Mineralization was lower in all regions of the cases (inferior: -3.3%; posterior: -3.1%; anterior: -2.7%; superior: -1.6%) compared to the controls. Mineralization density in cancellous bone was not regionally dependent but was lower in the fracture cases (-3.5%; P = 0.001). Although there were weak relationships between osteoid formation (%O.Ar/B.Ar) and the mean level of mineralization in both cortical (P = 0.068) and cancellous (P < 0.01) bone, adjustment for this did not markedly affect the case-control differences. In conclusion, this study has shown that in cases of intracapsular hip fracture, matrix mineralization is reduced in the femoral neck. Unexpectedly, in view of the likely role of mild to moderate vitamin D deficiency osteopathy in hip fracture, this decreased mineralization was independent of osteoid indices and therefore potentially independent of bone age. This raises the possibility that alterations in the bone matrix such as excessive glycation or changes in the composition of the collagen fibrils affect its mineralization in hip fracture cases.
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Affiliation(s)
- Nigel Loveridge
- Bone Research Group (MRC), University of Cambridge Clinical School, Cambridge, UK.
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32
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Boivin G, Meunier PJ. Methodological considerations in measurement of bone mineral content. Osteoporos Int 2003; 14 Suppl 5:S22-7; discussion S27-8. [PMID: 14504702 DOI: 10.1007/s00198-003-1469-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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33
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Goldman HM, Bromage TG, Boyde A, Thomas CDL, Clement JG. Intrapopulation variability in mineralization density at the human femoral mid-shaft. J Anat 2003; 203:243-55. [PMID: 12924824 PMCID: PMC1571158 DOI: 10.1046/j.1469-7580.2003.00212.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
One of several microstructural variables known to affect the mechanical properties of bone is the degree of mineralization of bone matrix. The aim of this study was to examine mineralization density, and its variability with age and sex, from a biomechanical perspective. Histological sections, prepared from mid-shaft femora obtained at autopsy from 40 individuals, were imaged using quantitative backscattered electron microscopy. Each cross-section montage was divided into 48 segments according to anatomical position. Mean grey-level values were quantified for each segment. One-way ANOVA with Tukey HSD post hoc tests were used to test for differences in mineralization between segments, age groups and sexes. Results showed a decrease in overall degree of mineralization density with adult age, but an increase in its coefficient of variation. Degree of mineralization was significantly lower in the periosteal third of the cortex, particularly in the antero-lateral aspect. This pattern was most prevalent amongst the youngest individuals in the sample. Whereas males between ages 45-64 years had a higher average degree of mineralization than females, the opposite was true of the older age group. Mineralization significantly decreased between middle and older age groups in males, but not in females. Despite limited consistencies in the location of high and low average mineralization bone through the cortex, the degree of interindividual variation, even within a single age and sex group, overwhelmed population level trends. The patterns of variability identified in this study are consistent with results of an analysis of collagen fibre orientation using the same sample material.
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Affiliation(s)
- H M Goldman
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA.
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34
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Abstract
This review presents findings made in studies of large mammalian bones, especially from racehorse training experiments (2-8 years old, third metacarpal, tarsal) and human autopsy orthopaedic femoral implant retrievals and other human biopsy and autopsy cases. Samples were cleaned to analyse mineralized matrix in three dimensions, or poly methyl-methacrylate embedded and micromilled to delete topography and study the superficial c. 0.5-microm two-dimensional section using quantitative backscattered electron imaging. With experimental implant studies in rabbits, observations were also made in vivo using confocal microscopy. Cracks in both calcified cartilage and bone may be removed by infilling with calcified matrix. This may be a general repair mechanism for calcified connective tissue crack repair. The fraction of the organ volume occupied by any form of bone tissue in equine distal third metacarpal extremities was increased in the more exercised groups by bone deposited within former marrow adipocytic space. Where deposited upon prior lamellar bone surfaces, this occurred without the intervention of prior resorption and without the formation of a hypermineralized cement line. Exercise inhibited osteoclastic resorption at external anatomical growth modelling sites where it normally occurs. Addition is not coupled to time-wasting resorption: both internally and externally, it occurs both by layering on existing cancellous surfaces and by creation of new immature scaffold, with de novo incorporation of a rich, capillary blood vessel supply. The real response within bone organs subjected to mechanical overload exercise within normal physiological limits is to make more, and to lose less, bone.
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Affiliation(s)
- Alan Boyde
- Department of Anatomy and Developmental Biology, University College London, UK.
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35
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Zizak I, Roschger P, Paris O, Misof BM, Berzlanovich A, Bernstorff S, Amenitsch H, Klaushofer K, Fratzl P. Characteristics of mineral particles in the human bone/cartilage interface. J Struct Biol 2003; 141:208-17. [PMID: 12648567 DOI: 10.1016/s1047-8477(02)00635-4] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bone and cartilage consist of different organic matrices, which can both be mineralized by the deposition of nano-sized calcium phosphate particles. We have studied these mineral particles in the mineralized cartilage layer between bone and different types of cartilage (bone/articular cartilage, bone/intervertebral disk, and bone/growth cartilage) of individuals aged 54 years, 12 years, and 6 months. Quantitative backscattered electron imaging and scanning small-angle X-ray scattering at a synchrotron radiation source were combined with light microscopy to determine calcium content, mineral particle size and alignment, and collagen orientation, respectively. Mineralized cartilage revealed a higher calcium content than the adjacent bone (p<0.05 for all samples), whereas the highest values were found in growth cartilage. Surprisingly, we found the mineral platelet width similar for bone and mineralized cartilage, with the exception of the growth cartilage sample. The most striking result, however, was the abrupt change of mineral particle orientation at the interface between the two tissues. While the particles were aligned perpendicular to the interface in cartilage, they were oriented parallel to it in bone, reflecting the morphology of the underlying organic matrices. The tight bonding of mineralized cartilage to bone suggests a mechanical role for the interface of the two elastically different tissues, bone and cartilage.
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Affiliation(s)
- I Zizak
- Erich Schmid Institute of Materials Science and Metal Physics Institute, Austrian Academy of Sciences and University of Leoben, Jahnstr. 12, A-8700, Leoben, Austria
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36
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Roschger P, Gupta HS, Berzlanovich A, Ittner G, Dempster DW, Fratzl P, Cosman F, Parisien M, Lindsay R, Nieves JW, Klaushofer K. Constant mineralization density distribution in cancellous human bone. Bone 2003; 32:316-23. [PMID: 12667560 DOI: 10.1016/s8756-3282(02)00973-0] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The degree of mineralization of bone matrix is an important factor in determining the mechanical competence of bone. The remodeling and modeling activities of bone cells together with the time course of mineralization of newly formed bone matrix generate a characteristic bone mineralization density distribution (BMDD). In this study we investigated the biological variance of the BMDD at the micrometer level, applying a quantitative backscattered electron imaging (qBEI) method. We used the mean calcium concentration (Ca(Mean)), the most frequent calcium concentration (Ca(Peak)), and full width at half maximum (Ca(Width)) to characterize the BMDD. In none of the BMDD parameters were statistically significant differences found due to ethnicity (15 African-American vs. 27 Caucasian premenopausal women), skeletal site variance (20 ilium, 24 vertebral body, 13 patella, 13 femoral neck, and 13 femoral head), age (25 to 95 years), or gender. Additionally, the interindividual variance of Ca(Mean) and Ca(Peak), irrespective of biological factors, was found to be remarkably small (SD < 2.1% of means). However, there are significant changes in the BMDD in the case of bone diseases (e.g., osteomalacia) or following clinical treatment (e.g., alendronate). From the lack of intraindividual changes among different skeletal sites we conclude that diagnostic transiliac biopsies can be used to determine the BMDD variables of cancellous bone for the entire skeleton of the patient. In order to quantify deviations from normal mineralization, a reference BMDD for adult humans was calculated using bone samples from 52 individuals. Because we find the BMDD to be essentially constant in healthy adult humans, qBEI provides a sensitive means to detect even small changes in mineralization due to bone disease or therapeutic intervention.
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Affiliation(s)
- P Roschger
- Ludwig Boltzmann Institute of Osteology, 4th Medical Department, Hanusch Hospital & UKH-Meidling, Vienna, Austria.
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37
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Ciarelli TE, Fyhrie DP, Parfitt AM. Effects of vertebral bone fragility and bone formation rate on the mineralization levels of cancellous bone from white females. Bone 2003; 32:311-5. [PMID: 12667559 DOI: 10.1016/s8756-3282(02)00975-4] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Back-scattered electron microscopy was used to study mineralization levels of human iliac cancellous bone of white females (N = 49). Mineralization levels were assessed by converting bone pixel grayscale levels to atomic number (Z) using known calibration standards. The data set consisted of bone biopsies from normal and vertebral fracture subjects that had either high or low values for bone formation rate (BFR(s)) within their respective groups (fracture/low BFR(s), N = 12; fracture/high BFR(s), N = 10; normal/low BFR(s), N = 12; normal/high BFR(s), N = 15). The following three measures of mineralization were quantitatively determined for each specimen: an overall mean mineralization (Z(mean)), the mineralization of trabecular packets deep within the interior of trabeculae (Z(deep)), and the mineralization of superficial exterior packets (Z(superficial)). Two-way analysis of variance revealed that the high BFR(s) group had a significantly lower Z(superficial) than the low BFR(s) group [mean (SD) 10.383 (0.270) vs. 10.563 (0.289)], and there was no significant interaction. BFR(s) had no effect on Z(mean) or Z(deep). For the pooled data, Z(deep) was significantly higher than Z(superficial) [10.866 (0.242) vs. 10.471 (0.291)]. There was no significant difference in Z(mean), Z(deep), or Z(superficial) between normals and those with vertebral fracture, but the standard deviations of the mineralization measures in the fracture group were at least double that of the normal group. Frequency histograms show that the two groups have fundamentally different mineralization distributions. The normal group demonstrates typical Gaussian distributions centered around the mean, and the distributions of the fracture group are bimodal, with peaks occurring at either the high or low tails of the distributions of the normal group. We hypothesize that both low and high patterns of mineralization might detrimentally affect bone material properties, with low mineralization levels causing reduced stiffness and strength and high mineralization resulting in reduced fracture toughness. The degree to which the mineralization differences may affect strength and stiffness of individual elements is estimated. The higher standard deviations of mineralization measures in the fracture group may reflect an inability to properly regulate trabecular level stress and strain. Forward stepwise regression analysis showed significant relationships between Ob.S/OS and both Z(superficial) and Z(mean), suggesting that the osteoblast may play an important role in regulating mineralization.
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Affiliation(s)
- T E Ciarelli
- Bone and Joint Center, Henry Ford Hospital, Detroit, MI 48202, USA
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38
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Benjamin M, Kumai T, Milz S, Boszczyk BM, Boszczyk AA, Ralphs JR. The skeletal attachment of tendons--tendon "entheses". Comp Biochem Physiol A Mol Integr Physiol 2002; 133:931-45. [PMID: 12485684 DOI: 10.1016/s1095-6433(02)00138-1] [Citation(s) in RCA: 317] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Tendon entheses can be classed as fibrous or fibrocartilaginous according to the tissue present at the skeletal attachment site. The former can be "bony" or "periosteal", depending on whether the tendon is directly attached to bone or indirectly to it via the periosteum. At fibrocartilaginous entheses, the uncalcified fibrocartilage dissipates collagen fibre bending and tendon narrowing away from the tidemark; calcified fibrocartilage anchors the tendon to the bone and creates a diffusion barrier between the two. Where there are additional fibrocartilaginous specialisations in the tendon and/or bone next to the enthesis, an "enthesis organ" is created that reduces wear and tear. Little attention has been paid to bone at entheses, despite the obvious bearing this has on the mechanical properties of the interface and the clinical importance of avulsion fractures. Disorders at entheses (enthesopathies) are common and occur in conditions such as diffuse idiopathic skeletal hyperostosis and the seronegative spondyloarthropathies. They are also commonly seen as sporting injuries such as tennis elbow and jumper's knee.
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Affiliation(s)
- M Benjamin
- School of Biosciences, P.O. Box 911, Museum Avenue, Cardiff University, Cardiff CF10 3US, Wales, UK.
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Geoffroy V, Kneissel M, Fournier B, Boyde A, Matthias P. High bone resorption in adult aging transgenic mice overexpressing cbfa1/runx2 in cells of the osteoblastic lineage. Mol Cell Biol 2002; 22:6222-33. [PMID: 12167715 PMCID: PMC134019 DOI: 10.1128/mcb.22.17.6222-6233.2002] [Citation(s) in RCA: 200] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The runt family transcription factor core-binding factor alpha1 (Cbfa1) is essential for bone formation during development. Surprisingly, transgenic mice overexpressing Cbfa1 under the control of the 2.3-kb collagen type I promoter developed severe osteopenia that increased progressively with age and presented multiple fractures. Analysis of skeletally mature transgenic mice showed that osteoblast maturation was affected and that specifically in cortical bone, bone resorption as well as bone formation was increased, inducing high bone turnover rates and a decreased degree of mineralization. To understand the origin of the increased bone resorption, we developed bone marrow stromal cell cultures and reciprocal coculture of primary osteoblasts and spleen cells from wild-type or transgenic mice. We showed that transgenic cells of the osteoblastic lineage induced an increased number of tartrate-resistant acid phosphatase-positive multinucleated cells, suggesting that primary osteoblasts as well as bone marrow stromal cells from transgenic mice have stronger osteoclastogenic properties than cells derived from wild-type animals. We investigated the candidate genes whose altered expression could trigger this increase in bone resorption, and we found that the expression of receptor activator of NF-kappaB ligand (RANKL) and collagenase 3, two factors involved in bone formation-resorption coupling, was markedly increased in transgenic cells. Our data thus suggest that overexpression of Cbfa1 in cells of the osteoblastic lineage does not necessarily induce a substantial increase in bone formation in the adult skeleton but has a positive effect on osteoclast differentiation in vitro and can also dramatically enhance bone resorption in vivo, possibly through increased RANKL expression.
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MESH Headings
- Aging/metabolism
- Animals
- Bone Density
- Bone Diseases, Metabolic/genetics
- Bone Diseases, Metabolic/metabolism
- Bone Diseases, Metabolic/pathology
- Bone Marrow Cells/pathology
- Bone Matrix/metabolism
- Bone Resorption/genetics
- Bone Resorption/metabolism
- Bone Resorption/pathology
- Carrier Proteins/biosynthesis
- Carrier Proteins/genetics
- Cell Differentiation/physiology
- Cell Lineage
- Cells, Cultured/metabolism
- Cells, Cultured/pathology
- Coculture Techniques
- Collagen/genetics
- Collagenases/biosynthesis
- Collagenases/genetics
- Core Binding Factor Alpha 1 Subunit
- Core Binding Factors
- Female
- Genotype
- Glycoproteins/biosynthesis
- Glycoproteins/genetics
- Male
- Matrix Metalloproteinase 13
- Membrane Glycoproteins/biosynthesis
- Membrane Glycoproteins/genetics
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Transgenic
- Neoplasm Proteins
- Osteoblasts/metabolism
- Osteoclasts/pathology
- Osteoprotegerin
- Promoter Regions, Genetic
- RANK Ligand
- Receptor Activator of Nuclear Factor-kappa B
- Receptors, Cytoplasmic and Nuclear/biosynthesis
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Tumor Necrosis Factor
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/physiology
- Spleen/pathology
- Stromal Cells/pathology
- Transcription Factors/genetics
- Transcription Factors/physiology
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Affiliation(s)
- Valérie Geoffroy
- Friedrich-Miescher Institute for Biomedical Research, Zweigniederlassung Novartis Forschungsstiftung,Basel, Switzerland
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Paredes Y, Massicotte F, Pelletier JP, Martel-Pelletier J, Laufer S, Lajeunesse D. Study of the role of leukotriene B()4 in abnormal function of human subchondral osteoarthritis osteoblasts: effects of cyclooxygenase and/or 5-lipoxygenase inhibition. ARTHRITIS AND RHEUMATISM 2002; 46:1804-12. [PMID: 12124864 DOI: 10.1002/art.10357] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To compare the effect of licofelone, NS-398 (an inhibitor of cyclooxygenase 2 [COX-2]), and BayX-1005 (an inhibitor of 5-lipoxygenase activating protein) on the production of leukotriene B(4) (LTB(4)) and prostaglandin E(2) (PGE(2)), and on cell biomarkers by human osteoarthritis (OA) subchondral osteoblasts. METHODS Primary in vitro osteoblasts were prepared from subchondral bone specimens obtained from OA patients and autopsy subjects. LTB(4) and PGE(2) levels were measured by enzyme-linked immunosorbent assay in conditioned media of osteoblasts incubated in the presence or absence of licofelone, NS-398, or BayX-1005. The effect of these drugs or of the addition of LTB(4) on alkaline phosphatase (AP) activity and osteocalcin release by OA and normal osteoblasts was determined. The presence of LTB(4) receptors in normal and OA osteoblasts was evaluated by Western blot analysis. RESULTS OA osteoblasts produced variable levels of PGE(2) and LTB(4) compared with normal osteoblasts. Licofelone, at the maximal dose used, inhibited production of PGE(2) and LTB(4) by OA osteoblasts by a mean +/- SEM of 61.2 +/- 6.4% and 67.0 +/- 7.6%, respectively. NS-398 reduced PGE(2) production by 75.8 +/- 5.3%. BayX-1005 inhibited LTB(4) production in OA osteoblasts by 38.7 +/- 14.5% and marginally affected PGE(2) levels (reduction of 14.8 +/- 5.3%). Licofelone dose-dependently stimulated 1,25-dihydroxyvitamin D-induced AP activity while inhibiting osteocalcin release. BayX-1005 partly reproduced these effects, but NS-398 failed to affect them. LTB(4) dose-dependently inhibited AP activity in OA osteoblasts, while its effect on osteocalcin depended on endogenous LTB(4) levels in these cells. In normal osteoblasts, LTB(4) dose-dependently stimulated osteocalcin, whereas it failed to influence AP. LTB(4) receptors BLT1 and BLT2 were present in normal and OA osteoblasts. CONCLUSION Licofelone inhibits the production of PGE(2) and LTB(4). Selective effects of licofelone on AP and osteocalcin occur via its role on LTB(4) production. Because LTB(4) can modify cell biomarkers in OA and normal osteoblasts, our results suggest licofelone could modify abnormal bone remodeling in OA.
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Affiliation(s)
- Yosabeth Paredes
- Centre Hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Montreal, Quebec, Canada
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41
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Kalichman L, Cohen Z, Kobyliansky E, Livshits G. Interrelationship between bone aging traits and basic anthropometric characteristics. Am J Hum Biol 2002; 14:380-90. [PMID: 12001096 DOI: 10.1002/ajhb.10051] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Using plain hand radiographs, the age dependence of various bone-aging traits (bone mineral density [BMD], cortical index [CI], osteoarthritis [OA], and osseographic [OSS] scores) was evaluated to test whether the correlation among these traits is an individual- or population-based phenomenon. In addition, the effect of anthropometric features on variation of bone-aging traits was estimated. The study included 1,295 individuals from Chuvasha, Russia, 18 to 89 years. BMD was measured from the compact compartment of the middle and distal phalanges of both 3(rd) fingers. The CI of the II-IV metacarpal bones and II-IV proximal phalanges was obtained. The development of OA was based on the standard Kellgren and Lawrence grading scheme for 28 hand joints. OSS score, a surrogate measure that takes into account different kinds of bone changes, was also obtained for each individual. Body weight and height, eight skinfold thicknesses on the trunk and extremities, and breadths of the long bones were measured. Sex-based univariate analyses and multivariate statistical analysis showed the following: 1) Age dependence was defined more strongly in "OA-linked" compared to "osteoporosis (OP)-linked" traits; 2) While "OP-linked" bone-aging traits correlated with age differently between sexes, "OA-linked" traits did not; 3) The strong interrelationship between OA-linked and OP-linked traits in both sexes became very weak and statistically insignificant (P > 0.10) after adjustment for age. Thus, OA and OP conditions in the same individual develop independently and probably reflect different underlying physiological mechanisms. 4) Anthropometric characteristics were significantly correlated with bone-aging traits, but correlations were low (r < 0.20). Thus, the contribution of anthropometric characteristics to the rate and pattern of bone aging of the hand was to relatively small.
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Affiliation(s)
- Leonid Kalichman
- Research Unit, Human Population Biology, Department of Anatomy and Anthropology, the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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42
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Naganathan V, Macgregor A, Snieder H, Nguyen T, Spector T, Sambrook P. Gender differences in the genetic factors responsible for variation in bone density and ultrasound. J Bone Miner Res 2002; 17:725-33. [PMID: 11918230 DOI: 10.1359/jbmr.2002.17.4.725] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Although genetic factors are thought to explain a large proportion of the variation in bone density in women, few studies have been conducted in men. Therefore, it is unclear whether the individual differences in bone strength between men and women are a reflection of gender differences in the relative influence of genetic and environmental factors on bone density variance. The aim of this study was to determine if there were gender differences in the genetic components of variance for bone density and ultrasound. In addition, the study aimed to explore the hypothesis that there are unique gender-specific genetic determinants of these traits. Bone mineral density (BMD) of the hip, distal forearm, and lumbar spine were measured by dual-energy X-ray absorptiometry (DXA) as well as quantitative ultrasound (QUS) at the calcaneus in healthy female twin pairs (286 identical [MZ] and 265 nonidentical [DZ]), male twin pairs (72 MZ and 65 DZ), and 82 opposite-sex (OS) pairs aged between 18 and 80 years. For hip BMD, distal forearm, and QUS measurements, the differences between MZ correlations and like-sex DZ correlations were similar for both sexes, suggesting little difference in the component of total variance explained by genetic factors between male and female twin pairs. However, correlations between OS twin pairs were lower than that of like-sex twin pairs, suggesting the possibility of unique gender-specific genetic effects. At the forearm, model fitting suggested a small gender difference in the magnitude of genetic variance as well as the presence of a unique gender-specific genetic variance component. Hip, lumbar spine, and QUS measurements were better explained by models that assumed no gender differences in genetic variance between the sexes, but the study had insufficient power to detect small differences in the genetic components of variance. The results of this study suggest that the proportion of bone strength variance explained by genetic factors is similar for men and women. However, at some regions there is evidence to suggest a gender-specific genetic component to the overall genetic variance.
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Affiliation(s)
- Vasi Naganathan
- Institute of Bone and Joint Research, Department of Rheumatology, Royal North Shore Hospital, Sydney, Australia
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43
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Milz S, Rufai A, Buettner A, Putz R, Ralphs JR, Benjamin M. Three-dimensional reconstructions of the Achilles tendon insertion in man. J Anat 2002; 200:145-52. [PMID: 11895112 PMCID: PMC1570650 DOI: 10.1046/j.0021-8782.2001.00016.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The distribution of type II collagen in sagittal sections of the Achilles tendon has been used to reconstruct the three-dimensional (3D) shape and position of three fibrocartilages (sesamoid, periosteal and enthesis) associated with its insertion. The results showed that there is a close correspondence between the shape and position of the sesamoid and periosteal fibrocartilages--probably because of their functional interdependence. The former protects the tendon from compression during dorsiflexion of the foot, and the latter protects the superior tuberosity of the calcaneus. When the zone of calcified enthesis fibrocartilage and the subchondral bone are mapped in 3D, the reconstructions show that there is a complex pattern of interlocking between pieces of calcified fibrocartilage and bone at the insertion site. We suggest that this is of fundamental importance in anchoring the tendon to the bone, because the manner in which a tendon insertion develops makes it unlikely that many collagen fibres pass across the tissue boundary from tendon to bone. When force is transmitted to the bone from a loaded tendon, it is directed towards the plantar fascia by a series of highly orientated trabeculae that are clearly visible in 3D in thick resin sections.
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Affiliation(s)
- S Milz
- Anatomische Anstalt, Ludwig-Maximilians-Universität, Munich, Germany
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Benjamin M, McGonagle D. The anatomical basis for disease localisation in seronegative spondyloarthropathy at entheses and related sites. J Anat 2001; 199:503-26. [PMID: 11760883 PMCID: PMC1468363 DOI: 10.1046/j.1469-7580.2001.19950503.x] [Citation(s) in RCA: 324] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The 2 major categories of idiopathic inflammatory arthritis are rheumatoid arthritis and the seronegative spondyloarthropathies. Whilst the synovium is the primary site of joint disease in the former, the primary site in the latter is less well defined. However, it has recently been proposed that enthesitis-associated changes in the spondyloarthropathies are primary and that all other joint manifestations are secondary. Nevertheless, some of the sites of disease localisation have not been adequately explained in terms of enthesitis. This article summarises current knowledge of the structure, function, blood supply, innervation, molecular composition and histopathology of the classic enthesis (i.e. the bony attachment of a tendon or ligament) and introduces the concept of 'functional' and articular 'fibrocartilaginous' entheses. The former are regions where tendons or ligaments wrap-around bony pulleys, but are not attached to them, and the latter are synovial joints that are lined by fibrocartilage rather than hyaline cartilage. We describe how these 3 types of entheses relate to other, and how all are prone to pathological changes in spondyloarthropathy. We propose that the inflammatory responses characteristic of spondyloarthropathies are triggered at these seemingly diverse sites, in genetically susceptible individuals, by a combination of anatomical factors which lead to higher levels of tissue microtrauma, and the deposition of microbes.
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Affiliation(s)
- M Benjamin
- Anatomy Unit, School of Biosciences, Cardiff University, UK.
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Karasik D, Otremski I, Barach I, Yakovenko K, Batsevich V, Pavlovsky O, Kobyliansky E, Livshits G. Comparative analysis of age prediction by markers of bone change in the hand assessed by roentgenography. Am J Hum Biol 2001; 11:31-43. [PMID: 11533931 DOI: 10.1002/(sici)1520-6300(1999)11:1<31::aid-ajhb3>3.0.co;2-l] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The major aim of this study was to develop an accurate method of age prediction for a wide range of ages based on the roentgenographic assessment of the hand bones. Such a method may be of particular interest in paleoanthropology and forensic medicine. The present paper provides the results of an analysis of individuals belonging to two ethnically different population samples: 1) Chuvasha (the Russian Federation), 293 males and 254 females, aged 18-91 and 18-86 years, respectively; and 2) Turkmenians (the Republic of Turkmenia), 257 males and 386 females, aged 18-82 and 17-83 years, respectively. The hands of study participants were roentgenographed with standard methodology. For each roentgenogram an equidistant osseographic score (OSS) including the descriptive criteria of bone age was estimated. In addition, an osteoarthritic and an osteoporotic score (OA and OP, respectively) were assigned to each individual. OA was a modification of the Kellgren/Lawrence scale, whereas the OP was locally developed. Results of the multiple logistic regression analysis clearly indicated that OSS is a strong predictor variable of an individual's age, with R reaching 0.93 in Chuvasha and 0.89 in Turkmenians (P < 0.001). The standard errors of estimate were approximately +/-5-7 years and compared favorably with most known methods of age assessment using bones. This study provides an efficient method of age prediction, with acceptable accuracy, and extends the upper limit of prediction to the age of 70 years. An additional finding of interest was the coexistence of OA and OP in the bones of the same hand. The observed correlation between these two conditions reached 0.8 (P < 0.001). Am. J. Hum. Biol. 11:31-43, 1999. Copyright 1999 Wiley-Liss, Inc.
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Affiliation(s)
- David Karasik
- Research Unit-Human Population Biology, Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
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Roschger P, Rinnerthaler S, Yates J, Rodan GA, Fratzl P, Klaushofer K. Alendronate increases degree and uniformity of mineralization in cancellous bone and decreases the porosity in cortical bone of osteoporotic women. Bone 2001; 29:185-91. [PMID: 11502482 DOI: 10.1016/s8756-3282(01)00485-9] [Citation(s) in RCA: 311] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The strength of bone is correlated with bone mass but is also influenced significantly by other factors such as structural properties of the matrix (e.g., collagen mutations) and the mineral. Changes at all levels of this organization could contribute to fracture risk. We investigated the effects of alendronate (Aln) treatment on the density of mineralization and the ultrastructure of the mineral/collagen composite, size and habitus of mineral particles in iliac cancellous bone, as well as on the porosity of iliac cortical bone from postmenopausal osteoporotic women. Twenty-four transiliac bone biopsies from Phase III Aln (10 mg/day) trials (placebo and Aln after 2 and 3 years of treatment, n = 6 per group) were studied. The mineral structure was investigated by quantitative backscattered electron imaging (qBEI) and by scanning small-angle X-ray scattering (scanning-SAXS). qBEI histograms reflect the bone mineralization density distribution (BMDD), whereas SAXS patterns characterize the size and arrangement of the mineral particles in bone. We found that: (i) the relative calcium content of osteoporotic bone was significantly lower than that of data-base controls; (ii) mineralization was significantly higher and more uniform after Aln treatment; (iii) size and habitus of the mineral particles was not different between placebo and Aln-treated groups; and (iv) the porosity of cortical bone was reduced significantly by Aln treatment. We conclude that Aln treatment increases the degree and uniformity of bone matrix mineralization without affecting the size and habitus of the mineral crystals. It also decreases the porosity of the corticalis. Together these effects may contribute to the observed reduction in fractures.
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Affiliation(s)
- P Roschger
- Ludwig Boltzmann Institute of Osteology, Fourth Medical Department, Hanusch Krankenhaus and Unfallkrankenhaus Meidling, Vienna, Austria
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47
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Kneissel M, Boyde A, Gasser JA. Bone tissue and its mineralization in aged estrogen-depleted rats after long-term intermittent treatment with parathyroid hormone (PTH) analog SDZ PTS 893 or human PTH(1-34). Bone 2001; 28:237-50. [PMID: 11248653 DOI: 10.1016/s8756-3282(00)00448-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Intermittently administered parathyroid hormone (PTH) is a potent bone anabolic agent. We aimed to determine the impact of long-term treatment with PTH on bone structure, dynamics, and mineralization. We ovariectomized (ovx) 1-year-old rats with the exception of a baseline and a sham-operated group. Twelve weeks later, a 36 week treatment with PTH analog SDZ PTS 893 (12.5, 25, 50, 100 microg/kg), human PTH(1-34) (25, 50, 100 microg/kg), or vehicle (ovx, sham) was initiated. Bone dynamics, structure, and mineralization were evaluated in the lumbar spine and in the femoral diaphysis. Cancellous bone turnover was elevated 12 weeks postovariectomy in estrogen-deficient, vehicle-treated animals, but returned to the level of the sham group by 48 weeks. The animals experienced substantial cancellous bone loss associated with a reduction of trabecular number and presented with a partly rod-like trabecular network. After 36 weeks of treatment with SDZ PTS 893 or human PTH(1-34), cancellous bone formation rates and turnover were raised in all treated groups compared with age-matched controls. The mineral apposition rate was increasing with dose. This amplified matrix synthesis led to trabecular thickening, but not to an increase in trabecular number, resulting in a crude, plate-like cancellous network with a high bone volume fraction. Fluorochrome label-based cortical bone dynamics demonstrated that a thick ring of new bone was formed at the endocortex by activation of modeling drifts during treatment. Treatment-induced cortical bone formation was increased with dose at the subperiosteal and endocortical envelopes, but substantially higher at the latter. Intracortical bone turnover was elevated near the endocortex. Bone mineralization was undisturbed in all compartments. The average degree of mineralization was lowered slightly, reflecting the increased portion of new bone formed during treatment. In summary, the main anabolic effect was mediated for both peptides by an increase in bone apposition with dose, persisting throughout treatment that lasted more than one third of the lifespan of the rats, and direct activation of bone-forming surfaces. As a result, a substantial amount of new bone, maintained at elevated turnover and adequate mineralization levels, formed predominantly at compartments exposed to bone marrow.
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Affiliation(s)
- M Kneissel
- Bone Metabolism Unit, Therapeutic Area of Arthritis and Bone Metabolism, Novartis Pharma AG, Basel, Switzerland.
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48
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SHEA JE, VAJDA EG, BLOEBAUM RD. Evidence of a hypermineralised calcified fibrocartilage on the human femoral neck and lesser trochanter. J Anat 2001; 198:153-62. [PMID: 11273040 PMCID: PMC1468213 DOI: 10.1046/j.1469-7580.2001.19820153.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Femoral neck fractures are a major cause of morbidity and mortality in elderly humans. In addition to the age-related loss of cancellous bone, changes to the microstructure and morphology of the metaphyseal cortex may be a contributing factor in osteoporotic hip fractures. Recent investigations have identified a hypermineralised tissue on the neck of the femur and trochanteric region that increases in fractional area with advancing age in both males (Boyce & Bloebaum, 1993) and females (Vajda & Bloebaum, 1999). The aim of this study was to determine if the hypermineralised tissue previously observed on the proximal femur is calcified fibrocartilage. Regional variations in the fractional area of hypermineralised tissue, cortical bone, and porosity of the cortical bone along the neck of the femur and lesser trochanter were also quantified. Comparison of back scattered electron and light microscope images of the same area show that regions of hypermineralised tissue correlate with the regions of calcified fibrocartilage from tendon and capsular insertions. The hypermineralised tissue and calcified fibrocartilage had similar morphological features such as the interdigitations of the calcified fibrocartilage into the bone, lacunar spaces, and distinctly shaped pores adjacent to the 2 tissues. Regions of the neck that did not contain insertions were covered with periosteum. There were no regional differences (P > 0.05) on the superior and inferior femoral neck in terms of the percentage area of hypermineralised calcified fibrocartilage, cortical bone, or cortical bone porosity. The lesser trochanter exhibited regional differences in the fractional area of hypermineralised calcified fibrocartilage (P = 0.007) and cortical bone (P = 0.007) but not porosity of the cortical bone (P > 0.05). The effects of calcified fibrocartilage on femoral neck periosteal expansion, repair, and mechanics are unknown, but may play a role in osteoporotic fractures and intracapsular fracture healing.
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Affiliation(s)
- J. E.
SHEA
- Bone and Joint Research Laboratory, VA Medical Center, Salt Lake City, UT, USA
| | | | - R. D.
BLOEBAUM
- Bone and Joint Research Laboratory, VA Medical Center, Salt Lake City, UT, USA
- Correspondence to Dr Roy D. Bloebaum, VAMC, 151F, Salt Lake City, UT 84148. Tel.: +1 (801) 582-1565 ext. 4607; fax +1 (801) 584-2533; e-mail:
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Kingsmill VJ. Post-extraction remodeling of the adult mandible. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 2000; 10:384-404. [PMID: 10759415 DOI: 10.1177/10454411990100030801] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Following tooth loss, the mandible shows an extensive loss of bone in some individuals. This may pose a significant problem in the prosthodontic restoration of function and esthetics. The many factors which have been proposed as being responsible for the inter-individual variation in post-extraction remodeling mean that a perfunctory analysis of the literature, in which well-controlled, relevant studies are scarce, may not provide the whole story. This article reviews the local and systemic factors which may play a role in the post-extraction remodeling of the mandible. Since severe residual ridge resorption may occur even when the bone status in the rest of the skeleton is good and vice versa, it is concluded that local functional factors are of paramount significance. It is now essential to determine how they can be modified and applied to help maintain ridge height and quality in our aging, edentulous population.
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Affiliation(s)
- V J Kingsmill
- Department of Conservative Dentistry, St Bartholomew's and the Royal London School of Medicine and Dentistry, UK
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50
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Abstract
Hip fracture incidence increases exponentially with age in virtually every human population that has been studied. In spite of this, relatively few studies have examined age-related changes in the metaphyseal cortex of the proximal femur. The present study investigates cortical aging changes in the female proximal femur, with particular reference to regions of hypermineralization. Thirty-three femora from Caucasian females were obtained at autopsy and analyzed using backscattered electron imaging. Variations in hypermineralized tissue area, cortical bone area, and porosity were quantified with standard stereological methods. Cortical width was quantified with digital calipers. Gender differences were examined by statistical comparison with previously published results. Hypermineralized tissue volume was significantly (P < 0.001) greater in elderly individuals. Hypermineralized tissue preferentially appeared near ligamentous or tendinous insertion sites, suggesting the hypermineralized tissue may be a calcified fibrocartilage. Cortical width significantly (P < 0.001) decreased with age and porosity significantly (P < 0.001) increased with age, however the changes were site-specific. The femoral neck and intertrochanteric cortices had a smaller change in cortical width and porosity with age than the diaphysis, but the femoral neck and intertrochanteric cortices had a larger increase in hypermineralized tissue. Comparison with previous data suggests that cortical aging in the proximal femur is similar between males and females and is unlikely to explain the higher incidence of fracture in females. However, the data strongly indicates that age-related changes in the femoral diaphysis cannot be directly extrapolated to either the femoral neck or intertrochanteric cortices.
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Affiliation(s)
- E G Vajda
- Bone and Joint Research Laboratory, VA Medical Center, Salt Lake City, Utah 84148, USA
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