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Rokidi S, Paschalis EP, Klaushofer K, Vennin S, Desyatova A, Turner JA, Watson P, Lappe J, Akhter MP, Recker RR. Organic matrix quality discriminates between age- and BMD-matched fracturing versus non-fracturing post-menopausal women: A pilot study. Bone 2019; 127:207-214. [PMID: 31229674 DOI: 10.1016/j.bone.2019.06.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/16/2019] [Accepted: 06/20/2019] [Indexed: 12/29/2022]
Abstract
Women with similar areal Bone Mineral Densities (BMD) may show divergent fracture incidence due to differences in bone quality. The hypothesis tested in the present pilot study is that postmenopausal (PM) women who have sustained osteoporotic fractures have altered organic matrix quality compared to those who have not. We used Raman microspectroscopy to analyze transiliac biopsies collected from fracturing (n = 6, mean age 62.5 ± 7.4 yrs; Cases) and non-fracturing PM women (n = 6, age- and BMD-matched; mean age 62.2 ± 7.3 yrs; Controls). Previous results show differences in intrinsic material properties by nanoindentation that are more homogenously distributed and could facilitate microcrack propagation in Cases, along with lower mineral carbonate/phosphate ratio by Fourier transform infrared spectroscopic imaging, and no differences in bone tissue mineralization by digitized microradiography. No differences between groups were seen by conventional histomorphometry. Spectra were acquired 2 μm away from previously performed nanoindents, in cortical and cancellous compartments. The determined parameters were: mineral to matrix ratio (MM), and nanoporosity (a surrogate for tissue water (TW)), glycosaminoglycan (GAG), pyridinoline (Pyd; trivalent enzymatic collagen cross-link), N(6)-carboxymethyllysine (CML; advanced glycation endproduct), and pentosidine (PEN; advanced glycation endproduct) content. ANCOVA indicated no differences in any of the spectroscopic outcomes between cancellous and cortical compartments. On the other hand, Cases had lower nanoporosity (TW) and GAG, and elevated Pyd, and CML content compared to Controls. In conclusion, the results of the present study indicate significant differences in organic matrix quality in PM women that sustain fragility fractures versus age- and BMD-matched controls, highlighting its importance as a potential independent determinant of fracture incidence.
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Affiliation(s)
- S Rokidi
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna Austria
| | - E P Paschalis
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna Austria.
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna Austria
| | - S Vennin
- Iniversity of Nebraska-Lincoln, NE, USA
| | | | | | - P Watson
- Osteoporosis Research Center, Creighton University, Omaha, NE, USA
| | - J Lappe
- Osteoporosis Research Center, Creighton University, Omaha, NE, USA
| | - M P Akhter
- Osteoporosis Research Center, Creighton University, Omaha, NE, USA
| | - R R Recker
- Osteoporosis Research Center, Creighton University, Omaha, NE, USA
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2
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Roschger A, Roschger P, Wagermaier W, Chen J, van Tol AF, Repp F, Blouin S, Berzlanovich A, Gruber GM, Klaushofer K, Fratzl P, Weinkamer R. The contribution of the pericanalicular matrix to mineral content in human osteonal bone. Bone 2019; 123:76-85. [PMID: 30898694 DOI: 10.1016/j.bone.2019.03.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/08/2019] [Accepted: 03/15/2019] [Indexed: 01/11/2023]
Abstract
The osteocyte lacunar-canalicular network (LCN) penetrates bone and houses the osteocytes and their processes. Despite its rather low volume fraction, the LCN represents an outstanding large surface that is possibly used by the osteocytes to interact with the surrounding mineralized bone matrix thereby contributing to mineral homeostasis. The aim of this study was to quantitatively describe such contributions by spatially correlating the local density of the LCN with the mineral content at the same location in micrometer-sized volume elements in human osteons. For this purpose, 65 osteons from the femur midshaft from healthy adults (n = 4) and children (n = 2) were structurally characterized with two different techniques. The 3D structure of the LCN in the osteons was imaged with confocal laser scanning microscopy after staining the bone samples with rhodamine. Subsequent image analysis provided the canalicular length density, i.e. the total length of the canaliculi per unit volume (μm/μm3). Quantitative information on the mineral content (wt%Ca) from the identical regions was obtained using quantitative backscattered electron imaging. As the LCN-porosity lowers the mineral content, a negative correlation between Ca content and network density was expected. Calculations predict a reduction of around -0.97 fmol Ca per μm of network. However, the experiment revealed for 62 out of 65 osteons a positive correlation resulting in an average additional Ca loading of +1.15 fmol per μm of canalicular network, i.e. an accumulation of mineral has occurred at dense network regions. We hypothesize that this accumulation happens in the close vicinity of canaliculi forming mineral reservoirs that can be utilized by osteocytes. Significant differences found between individuals indicate that the extent of mineral loading of the reservoir zone reflects an important parameter for mineral homeostasis.
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Affiliation(s)
- A Roschger
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, 14476 Potsdam, Germany; Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria.
| | - P Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - W Wagermaier
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, 14476 Potsdam, Germany
| | - J Chen
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, 14476 Potsdam, Germany; College of Engineering, Mathematics, and Physical Science, University of Exeter, Exeter EX4 4QF, UK
| | - A F van Tol
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, 14476 Potsdam, Germany
| | - F Repp
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, 14476 Potsdam, Germany
| | - S Blouin
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - A Berzlanovich
- Department of Forensic Medicine, Medical University of Vienna, Sensengasse 2, A-1090 Vienna, Austria
| | - G M Gruber
- Department of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, A-1090 Vienna, Austria
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - P Fratzl
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, 14476 Potsdam, Germany
| | - R Weinkamer
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, 14476 Potsdam, Germany
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Paschalis EP, Gamsjaeger S, Condon K, Klaushofer K, Burr D. Estrogen depletion alters mineralization regulation mechanisms in an ovariectomized monkey animal model. Bone 2019; 120:279-284. [PMID: 30414509 DOI: 10.1016/j.bone.2018.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 11/05/2018] [Accepted: 11/06/2018] [Indexed: 12/14/2022]
Abstract
Ovariectomized animal models have been extensively used in osteoporosis research due to the resulting loss of bone mass. The purpose of the present study was to test the hypothesis that estrogen depletion alters mineralization regulation mechanisms in an ovariectomized monkey animal model. To achieve this we used Raman microspectroscopy to analyze humeri from monkeys that were either SHAM-operated or ovariectomized (N = 10 for each group). Measurements were made as a function of tissue age and cortical surface (periosteal, osteonal, endosteal) based on the presence of calcein fluorescent double labels. In the present work we focused on osteoid seams (defined as a surface with evident calcein labels, 1 μm distance away from the mineralizing front, and for which the Raman spectra showed the presence of organic matrix but not mineral), as well as the youngest mineralized tissue between the second fluorescent label and the mineralizing front, 1 μm inwards from the front with the phosphate mineral peak evident in the Raman spectra (TA1). The spectroscopically determined parameters of interest were the relative glycosaminoglycan (GAG) and pyridinoline (Pyd) contents in the osteoid, and the mineral content in TA1. At all three cortical surfaces, significant correlations were evident in the SHAM-operated animals between osteoid GAG (negative) and Pyd content, and mineral content, unlike the OVX animals. These results suggest that in addition to the well-established effects on turnover rates and bone mass, estrogen depletion alters the regulation of mineralization by GAGs and Pyd.
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Affiliation(s)
- E P Paschalis
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria.
| | - S Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - K Condon
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Department of Biomedical Engineering, Indiana University-Purdue University, Indianapolis (IUPUI), Indianapolis, IN 46202, USA
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - D Burr
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Department of Biomedical Engineering, Indiana University-Purdue University, Indianapolis (IUPUI), Indianapolis, IN 46202, USA
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Blouin S, Fratzl-Zelman N, Roschger A, Cabral WA, Klaushofer K, Marini JC, Fratzl P, Roschger P. Cortical bone properties in the Brtl/+ mouse model of Osteogenesis imperfecta as evidenced by acoustic transmission microscopy. J Mech Behav Biomed Mater 2018; 90:125-132. [PMID: 30366302 DOI: 10.1016/j.jmbbm.2018.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 09/24/2018] [Accepted: 10/03/2018] [Indexed: 10/28/2022]
Abstract
Higher skeletal fragility has been established for the Brtl/+ mouse model of osteogenesis imperfecta at the whole bone level, but previous investigations of mechanical properties at the bone material level were inconclusive. Bone material was analyzed separately at endosteal (ER) and periosteal regions (PR) on transverse femoral midshaft sections for 2-month old mice (wild-type n = 6; Brtl/+ n = 6). Quantitative backscattered electron imaging revealed that the mass density computed from mineral density maps was higher in PR than in ER for both wild-type (+2.1%, p < 0.05) and Brtl/+ mice (+1.8%, p < 0.05). Electron induced X-ray fluorescence analysis indicated significantly lower atomic Ca/P ratios and higher Na/Ca, Mg/Ca and K/Ca ratios in PR bone compared to ER independently of genotype. Second harmonic generation microscopy indicated that the occurrence of periodically alternating collagen orientation in ER of Brtl/+ mice was strongly reduced compared to wild-type mice. Scanning acoustic microscopy in time of flight mode revealed that the sound velocity and Young's modulus (estimated based on sound velocity and mass density maps) were significantly greater in PR (respectively +6% and +15%) compared to ER in wild-type mice but not in Brtl/+ mice. ER sound velocity and Young's modulus were significantly increased in Brtl/+ mice (+9.4% and +22%, respectively) compared to wild-type mice. These data demonstrate that the Col1a1 G349C mutation in Brtl/+ mice affects the mechanical behavior of bone material predominantly in the endosteal region by altering the collagen orientation.
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Affiliation(s)
- S Blouin
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria.
| | - N Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria
| | - A Roschger
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Postdam, Germany
| | - W A Cabral
- Bone and Extracellular Matrix Branch, National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria
| | - J C Marini
- Bone and Extracellular Matrix Branch, National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - P Fratzl
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Postdam, Germany
| | - P Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria
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Roetzer KM, Uyanik G, Brehm A, Zwerina J, Zandieh S, Czech T, Roschger P, Misof BM, Klaushofer K. Novel familial mutation of LRP5 causing high bone mass: Genetic analysis, clinical presentation, and characterization of bone matrix mineralization. Bone 2018; 107:154-160. [PMID: 29208525 DOI: 10.1016/j.bone.2017.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 12/01/2017] [Accepted: 12/01/2017] [Indexed: 12/29/2022]
Abstract
The Wnt signalling pathway is a critical regulator of bone mass and quality. Several heterozygous mutations in the LRP5 gene, a Wnt co-receptor, causing high bone mass (LRP5-HBM) have been described to date. The pathogenic mechanism is thought to be a gain-of-function caused by impaired inhibition of the canonical Wnt signalling pathway, thereby leading to increased bone formation. We report the cases of two affected family members, a 53-year-old mother and her 23-year-old daughter, with high bone mass (T-scores mother: lumbar spine 11.4, femoral neck 10.5; T-scores daughter: lumbar spine 5.4, femoral neck 8.7), increased calvarial thickness, and thickened cortices of the long bones but no history of fractures. Whereas the mother did not show any indications of the mutation, the daughter suffered from congenital hearing impairment resulting in cochlear implantation, recurrent facial palsy, and migraine. In addition, she had stenosis of the foramen magnum. In both individuals, we detected a novel heterozygous duplication of six basepairs in the LRP5 gene, resulting in an insertion of two amino acids, very likely associated with a gain-of-function. When the daughter had part of the occipital bone surgically removed, the bone sample was used for the visualization of bone lamellar structure and bone cells as well as the measurement of bone mineralization density distribution (BMDD). The bone sample revealed two distinctly different regions: an intra-cortical region with osteonal remodeling, typical osteonal lamellar orientation, associated with relatively higher heterogeneity of bone matrix mineralization, and another periosteal region devoid of bone remodeling, with parallel bone lamellae and lower heterogeneity of mineralization. In conclusion, we present data on bone tissue and material level from an LRP5-HBM patient with a novel mutation in the LRP5 gene. Our findings indicate normal morphology of osteoclasts and osteoblasts as well as normal mineralization in skull bone in LRP5-HBM.
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Affiliation(s)
- K M Roetzer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; Center for Medical Genetics, Hanusch Hospital, Vienna, Austria; Medical Faculty, Sigmund Freud University, Vienna, Austria
| | - G Uyanik
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; Center for Medical Genetics, Hanusch Hospital, Vienna, Austria; Medical Faculty, Sigmund Freud University, Vienna, Austria
| | - A Brehm
- 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - J Zwerina
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - S Zandieh
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; Department of Radiology and Nuclear Medicine, Hanusch Hospital, Vienna, Austria
| | - T Czech
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - P Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - B M Misof
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria.
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; 1st Medical Department, Hanusch Hospital, Vienna, Austria
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Misof B, Blouin S, Lueger S, Paschalis E, Recker R, Phipps R, Klaushofer K, Roschger P. Baseline mineralizing surface determines the magnitude of the bisphosphonate effect on cortical bone mineralization in postmenopausal osteoporotic patients. J Musculoskelet Neuronal Interact 2017; 17:183-191. [PMID: 28860420 PMCID: PMC5601263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To determine the effect of short- or long-term bisphosphonate treatment on cortical bone mineralization density distribution (BMDD). METHODS BMDD was assessed by quantitative backscatter electron imaging in postmenopausal osteoporosis: in paired transiliac biopsy samples (n=36) at baseline and after 3 years risedronate treatment from a clinical study, in transiliac biopsy samples from patients who were treated with either risedronate (n=31) or alendronate (n=68) for 3 to 7 years from an observational study. Outcomes were related to premenopausal reference data (n=73) and to histomorphometric mineralizing surface per bone surface (MS/BS). RESULTS In the clinical study, patients with lower (below cohort median) MS/BS had normal cortical CaMean at baseline. After 3 years risedronate, their CaMean was not different versus baseline but increased versus reference (+2.9%, p=0.003). Among the groups of the observational study, CaMean did not exceed reference level, was similar for alendronate versus risedronate and similar between 3 to 5 years versus longer than 5 years treatment duration. CONCLUSION Baseline bone mineralizing surface appears to be important for the effect of bisphosphonate on cortical bone mineralization. In patients with lower baseline MS/BS, level of mineralization after treatment can exceed reference level. Whether this is beneficial in the long-term is unknown.
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Affiliation(s)
- B.M. Misof
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria,Corresponding author: Dr. Barbara Misof, Ludwig Boltzmann Institute of Osteology, UKH Meidling, Kundratstr. 37, A-1120 Vienna, Austria E-mail:
| | - S. Blouin
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria
| | - S. Lueger
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria
| | - E.P. Paschalis
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria
| | - R.R. Recker
- Osteoporosis Research Center, Creighton University, Omaha, Nebraska, USA
| | - R. Phipps
- Husson University School of Pharmacy, Bangor, Maine, USA
| | - K. Klaushofer
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria
| | - P. Roschger
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Med. Dept. Hanusch Hospital, Vienna, Austria
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Abstract
Although musculoskeletal diseases such as osteoporosis are diagnosed and treatment outcome is evaluated based mainly on routine clinical outcomes of bone mineral density (BMD) by DXA and biochemical markers, it is recognized that these two indicators, as valuable as they have proven to be in the everyday clinical practice, do not fully account for manifested bone strength. Thus, the term bone quality was introduced, to complement considerations based on bone turnover rates and BMD. Bone quality is an "umbrella" term that incorporates the structural and material/compositional characteristics of bone tissue. Vibrational spectroscopic techniques such as Fourier transform infrared microspectroscopy (FTIRM) and imaging (FTIRI), and Raman spectroscopy, are suitable analytical tools for the determination of bone quality as they provide simultaneous, quantitative, and qualitative information on all main bone tissue components (mineral, organic matrix, tissue water), in a spatially resolved manner. Moreover, the results of such analyses may be readily combined with the outcomes of other techniques such as histology/histomorphometry, small angle X-ray scattering, quantitative backscattered electron imaging, and nanoindentation.
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Affiliation(s)
- E P Paschalis
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, 1140, Vienna, Austria.
| | - S Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, 1140, Vienna, Austria
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, 1140, Vienna, Austria
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Brozek W, Reichardt B, Zwerina J, Dimai HP, Klaushofer K, Zwettler E. Use of proton pump inhibitors and mortality after hip fracture in a nationwide study. Osteoporos Int 2017; 28:1587-1595. [PMID: 28083667 DOI: 10.1007/s00198-017-3910-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 01/03/2017] [Indexed: 12/13/2022]
Abstract
UNLABELLED We analyzed the association of proton pump inhibitors (PPIs) with mortality after osteoporosis-related hip fracture in Austria. PPIs were associated with reduced 90-day mortality but elevated mortality after half a year when initiated pre-fracture. Inpatients and discharged patients on PPIs showed lowered in-hospital and 90-day mortality, respectively. INTRODUCTION We herein investigated use of proton pump inhibitors (PPIs) and mortality among hip fracture patients in a nationwide study in Austria. METHODS In this retrospective cohort study, data on use of PPIs were obtained from 31,668 Austrian patients ≥50 years with a hip fracture between July 2008 and December 2010. All-cause mortality in patients without anti-osteoporotic drug treatment who had received their first recorded PPI prescription in the study period either before or after fracture was compared with hip fracture patients on neither PPIs nor anti-osteoporotic medication using logistic and Cox regression analysis. RESULTS With PPI use, 90-day mortality was significantly reduced, both at initiation before (OR 0.66; p < 0.0001) and after hip fracture (OR 0.23; p < 0.0001). 90-day mortality was also reduced when PPIs were prescribed not until after discharge from the last recorded hip fracture-related hospital stay (OR 0.49; p < 0.0001) except for patients aged <70 years. In a sub-cohort of patients beginning PPIs during hospital stay, in-hospital mortality (0.2%) was substantially reduced relative to matched control patients (3.5%) (p < 0.0001). Longer-term mortality significantly increased after half a year post-fracture only among those who started PPI prescription before fracture. CONCLUSIONS PPI use during and after hospital stay due to hip fracture is associated with a considerable decrease in mortality. These findings could have implications for hip fracture treatment.
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Affiliation(s)
- W Brozek
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of the WGKK and AUVA Trauma Center, 1st Medical Department at Hanusch Hospital, Heinrich Collin Str. 30, 1140, Vienna, Austria.
| | - B Reichardt
- Sickness Fund Burgenland, Burgenländische Gebietskrankenkasse, Esterhazyplatz 3, 7000, Eisenstadt, Austria
| | - J Zwerina
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of the WGKK and AUVA Trauma Center, 1st Medical Department at Hanusch Hospital, Heinrich Collin Str. 30, 1140, Vienna, Austria
| | - H P Dimai
- Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of the WGKK and AUVA Trauma Center, 1st Medical Department at Hanusch Hospital, Heinrich Collin Str. 30, 1140, Vienna, Austria
| | - E Zwettler
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of the WGKK and AUVA Trauma Center, 1st Medical Department at Hanusch Hospital, Heinrich Collin Str. 30, 1140, Vienna, Austria
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9
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Paschalis EP, Gamsjaeger S, Hassler N, Klaushofer K, Burr D. Ovarian hormone depletion affects cortical bone quality differently on different skeletal envelopes. Bone 2017; 95:55-64. [PMID: 27826024 DOI: 10.1016/j.bone.2016.10.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 10/17/2016] [Accepted: 10/25/2016] [Indexed: 12/31/2022]
Abstract
The physical properties of bone tissue are determined by the organic and mineral matrix, and are one aspect of bone quality. As such, the properties of mineral and matrix are a major contributor to bone strength, independent of bone mass. Cortical bone quality may differ regionally on the three skeletal envelopes that compose it. Each of these envelopes may be affected differently by ovarian hormone depletion. Identifying how these regions vary in their tissue adaptive response to ovarian hormones can inform our understanding of how tissue quality contributes to overall bone strength in postmenopausal women. We analyzed humeri from monkeys that were either SHAM-operated or ovariectomized. Raman microspectroscopic analysis was performed as a function of tissue age based on the presence of multiple fluorescent double labels, to determine whether bone compositional properties (mineral/matrix ratio, tissue water, glycosaminoglycan, lipid, and pyridinoline contents, and mineral maturity/crystallinity) are similar between periosteal, osteonal, and endosteal surfaces, as well as to determine the effects of ovarian hormone depletion on them. The results indicate that mineral and organic matrix characteristics, and kinetics of mineral and organic matrix modifications as a function of tissue age are different at periosteal vs. osteonal and endosteal surfaces. Ovarian hormone depletion affects the three cortical surfaces (periosteal, osteonal, endosteal) differently. While ovarian hormone depletion does not significantly affect the quality of either the osteoid or the most recently mineralized tissue, it significantly affects the rate of subsequent mineral accumulation, as well as the kinetics of organic matrix modifications, culminating in significant differences within interstitial bone. These results highlight the complexity of the cortical bone compartments, add to existing knowledge on the effects of ovarian hormone depletion on local cortical bone properties, and may contribute to a better understanding of the location specific action of drugs used in the management of postmenopausal osteoporosis.
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Affiliation(s)
- E P Paschalis
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria.
| | - S Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - N Hassler
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - D Burr
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Department of Biomedical Engineering, Indiana University-Purdue University, Indianapolis (IUPUI), Indianapolis, IN 46202, USA
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Paschalis EP, Gamsjaeger S, Hassler N, Fahrleitner-Pammer A, Dobnig H, Stepan JJ, Pavo I, Eriksen EF, Klaushofer K. Vitamin D and calcium supplementation for three years in postmenopausal osteoporosis significantly alters bone mineral and organic matrix quality. Bone 2017; 95:41-46. [PMID: 27826025 DOI: 10.1016/j.bone.2016.11.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/30/2016] [Accepted: 11/02/2016] [Indexed: 12/15/2022]
Abstract
Prospective, controlled clinical trials in postmenopausal osteoporosis typically compare effects of an active drug with placebo in addition to vitamin D and calcium supplementation in both treatment arms. While clinical benefits are documented, the effect of this supplementation in the placebo arm and in clinical practice on bone material composition properties is unknown. The purpose of the present study was to evaluate these bone quality indices (specifically mineral/matrix, nanoporosity, glycosaminoglycan content, mineral maturity/crystallinity, and pyridinoline content) in patients that either received long-term vitamin D (400-1200IU) and calcium (1.0-1.5g) supplementation, or did not. We have analyzed by Raman microspectroscopy the bone forming trabecular surfaces of iliac crest in pre-treatment samples of a teriparatide study and the endpoint biopsies of the control arm obtained from the HORIZON trial. In general, the mineral/matrix ratio and the glycosaminoglycan (GAG) content was higher while nanoporosity, (a surrogate for tissue water content), the mineral maturity/crystallinity (MMC) and the pyridinoline (Pyd) content was lower in patients without long-term supplementation. Moreover, all indices were significantly dependent on tissue age. In conclusion, vitamin D and calcium supplementation is associated with altered mineral and organic matrix properties.
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Affiliation(s)
- E P Paschalis
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK, AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140, Vienna, Austria.
| | - S Gamsjaeger
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK, AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140, Vienna, Austria
| | - N Hassler
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK, AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140, Vienna, Austria
| | | | - H Dobnig
- Thyroid, Endocrinology, and Osteoporosis Institute, Graz, Austria
| | - J J Stepan
- Institute of Rheumatology, Faculty of Medicine 1, Charles University, Prague, Czech Republic
| | - I Pavo
- Endocrinology Dept., Oslo University Hospital, Norway
| | - E F Eriksen
- Endocrinology Dept., Oslo University Hospital, Norway
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK, AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140, Vienna, Austria
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11
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Rauwolf M, Turyanskaya A, Roschger A, Prost J, Simon R, Scharf O, Radtke M, Schoonjans T, Guilherme Buzanich A, Klaushofer K, Wobrauschek P, Hofstaetter JG, Roschger P, Streli C. Synchrotron radiation micro X-ray fluorescence spectroscopy of thin structures in bone samples: comparison of confocal and color X-ray camera setups. J Synchrotron Radiat 2017; 24:307-311. [PMID: 28009572 PMCID: PMC5182026 DOI: 10.1107/s1600577516017057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 10/24/2016] [Indexed: 06/06/2023]
Abstract
In the quest for finding the ideal synchrotron-radiation-induced imaging method for the investigation of trace element distributions in human bone samples, experiments were performed using both a scanning confocal synchrotron radiation micro X-ray fluorescence (SR-µXRF) (FLUO beamline at ANKA) setup and a full-field color X-ray camera (BAMline at BESSY-II) setup. As zinc is a trace element of special interest in bone, the setups were optimized for its detection. The setups were compared with respect to count rate, required measurement time and spatial resolution. It was demonstrated that the ideal method depends on the element of interest. Although for Ca (a major constituent of the bone with a low energy of 3.69 keV for its Kα XRF line) the color X-ray camera provided a higher resolution in the plane, for Zn (a trace element in bone) only the confocal SR-µXRF setup was able to sufficiently image the distribution.
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Affiliation(s)
| | | | - A. Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, Vienna, Austria
| | - J. Prost
- Atominstitut, TU Wien, Vienna, Austria
| | - R. Simon
- Forschungszentrum Karlsruhe/KIT, Institute for Synchrotron Radiation, ANKA, Karlsruhe, Germany
| | - O. Scharf
- IFG Institute of Scientific Instruments GmbH, Berlin, Germany
| | - M. Radtke
- Department of Analytical Chemistry, Bundesanstalt fuer Materialforschung und -pruefung, Berlin, Germany
| | - T. Schoonjans
- Department of Analytical Chemistry, Bundesanstalt fuer Materialforschung und -pruefung, Berlin, Germany
| | - A. Guilherme Buzanich
- Department of Analytical Chemistry, Bundesanstalt fuer Materialforschung und -pruefung, Berlin, Germany
| | - K. Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, Vienna, Austria
| | | | - J. G. Hofstaetter
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, Vienna, Austria
- Orthopaedic Hospital Vienna-Speising, Vienna, Austria
| | - P. Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, Vienna, Austria
| | - C. Streli
- Atominstitut, TU Wien, Vienna, Austria
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12
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Misof BM, Roschger P, Blouin S, Recker R, Klaushofer K. Bone matrix mineralization is preserved during early perimenopausal stage in healthy women: a paired biopsy study. Osteoporos Int 2016; 27:1795-803. [PMID: 26650378 DOI: 10.1007/s00198-015-3446-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/30/2015] [Indexed: 12/14/2022]
Abstract
UNLABELLED Bone matrix mineralization based on quantitative backscatter electron imaging remained unchanged during the first year of menopause in paired transiliac biopsy samples from healthy women. This suggests that the reported early perimenopausal reductions in bone mineral density are caused by factors other than decreases in the degree of mineralization. INTRODUCTION It is unknown whether perimenopausal loss of bone mass is associated with a drop in bone matrix mineralization. METHODS For this purpose, we measured the bone mineralization density distribution (BMDD) by quantitative backscatter electron imaging (qBEI) in n = 17 paired transiliac bone biopsy samples at premenopausal baseline and 12 months after last menses (obtained at average ages of 49 ± 2 and 55 ± 2 years, respectively) in healthy women. For interpretation of BMDD outcomes, previously measured bone mineral density (BMD) and biochemical and histomorphometric markers of bone turnover were revisited for the present biopsy cohort. RESULTS Menopause significantly decreased BMD at the lumbar spine (-4.5 %) and femoral neck (-3.8 %), increased the fasting urinary hydroxyproline/creatinine ratio (+60 %, all p < 0.01) and histomorphometric bone formation rate (+25 %, p < 0.05), but affected neither cancellous nor cortical BMDD variables (paired comparison p > 0.05). Mean calcium concentrations of cancellous (Cn.CaMean) and cortical bone (Ct.CaMean) were within normal range (p > 0.05 compared to established reference data). Ct.CaMean was significantly correlated with Cn.CaMean before (R = 0.81, p < 0.001) and after menopause (R = 0.80, p < 0.001) and to cortical porosity of mineralized tissue (Ct.Po.) after menopause (R = -0.57, p = 0.02). CONCLUSIONS Surprisingly, the BMDD was found not affected by the changes in bone turnover rates in this cohort. This suggests that the substantial increase in bone formation rates took place shortly before the second biopsy, and the bone mineralization changes lag behind. We conclude that during the first year after the last menses, the degree of bone matrix mineralization is preserved and does not contribute to the observed reductions in BMD.
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Affiliation(s)
- B M Misof
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Kundratstr. 37, A-1120, Vienna, Austria.
| | - P Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Kundratstr. 37, A-1120, Vienna, Austria
| | - S Blouin
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Kundratstr. 37, A-1120, Vienna, Austria
| | - R Recker
- Osteoporosis Research Center, Creighton University, Omaha, Nebraska, USA
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Kundratstr. 37, A-1120, Vienna, Austria
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13
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Brozek W, Reichardt B, Zwerina J, Dimai HP, Klaushofer K, Zwettler E. Antiresorptive therapy and risk of mortality and refracture in osteoporosis-related hip fracture: a nationwide study. Osteoporos Int 2016; 27:387-96. [PMID: 26576544 DOI: 10.1007/s00198-015-3415-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/09/2015] [Indexed: 11/30/2022]
Abstract
UNLABELLED We analyzed the association of bisphosphonate therapy with mortality and hip refracture incidence among osteoporosis-related hip fracture patients in Austria. Mortality was lower in primarily female bisphosphonate users, while hip refracture incidence was generally elevated relative to controls, indicating beneficial effects of bisphosphonates other than on bone. INTRODUCTION The purpose of this study was to analyze mortality and hip refracture risk in osteoporotic hip fracture patients with and without antiosteoporotic medication. METHODS We retrospectively analyzed data on 31,668 Austrian patients ≥50 years with a hip fracture between July 2008 and December 2010 for antiosteoporotic drug treatment with respect to outcome parameters all-cause mortality, hip refracture incidence, and hip refracture-free days. Outcomes when bisphosphonate (BP) treatment was begun before or after fracture were compared with an age- and sex-matched hip fracture control without antiosteoporotic medication. RESULTS 27.69 % of patients (33.01 % of women, 13.13 % of men) were prescribed antiosteoporotic medication, primarily BPs. Females having initiated BP treatment before first fracture had lower odds for mortality 1 and 3 year(s) post-fracture, whereas hip refracture incidence under pre-fracture BP initiation was generally higher. Treatment that was started after fracture, however, entailed significantly lower mortality hazards for both genders (HR 0.43, 95 %CI 0.36-0.52, p < 0.0001 after 1 year) but significantly higher hip refracture incidence except for patients aged 50-69 years and more hip refracture free days for females. Hip refractures overall amounted to 29.22/1000 patient years differing significantly between women and men (31.03 vs. 23.89, respectively, p < 0.0001), and longer hip refracture free survival was observed for women than for men (499 vs. 466 median days, respectively, p < 0.0001). CONCLUSIONS Although BP use is associated with reduced mortality after hip fracture, notably among women, hip refracture incidences are likewise elevated, which is most likely accounted for by a high probability of BP prescription to more comorbid patients suffering from more severe osteoporosis. Concomitantly, through possible effects other than on bone, BPs might be able to curtail mortality. Male hip fracture patients' low treatment frequency in particular reflects underdiagnosis and undertreatment of osteoporosis in Austria.
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Affiliation(s)
- W Brozek
- Ludwig Boltzmann Institute of Osteology, 1st Medical Department at Hanusch Hospital, Hanusch Hospital of the WGKK and AUVA Trauma Center, Heinrich Collin Str. 30, 1140, Vienna, Austria.
| | - B Reichardt
- Sickness Fund Burgenland, Burgenländische Gebietskrankenkasse, Esterhazyplatz 3, 7000, Eisenstadt, Austria
| | - J Zwerina
- Ludwig Boltzmann Institute of Osteology, 1st Medical Department at Hanusch Hospital, Hanusch Hospital of the WGKK and AUVA Trauma Center, Heinrich Collin Str. 30, 1140, Vienna, Austria
| | - H P Dimai
- Department of Internal Medicine, Division of Endocrinology and Nuclear Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology, 1st Medical Department at Hanusch Hospital, Hanusch Hospital of the WGKK and AUVA Trauma Center, Heinrich Collin Str. 30, 1140, Vienna, Austria
| | - E Zwettler
- Ludwig Boltzmann Institute of Osteology, 1st Medical Department at Hanusch Hospital, Hanusch Hospital of the WGKK and AUVA Trauma Center, Heinrich Collin Str. 30, 1140, Vienna, Austria
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Misof BM, Roschger P, Jorgetti V, Klaushofer K, Borba VZC, Boguszewski CL, Cohen A, Shane E, Zhou H, Dempster DW, Moreira CA. Subtle changes in bone mineralization density distribution in most severely affected patients with chronic obstructive pulmonary disease. Bone 2015; 79:1-7. [PMID: 26003953 DOI: 10.1016/j.bone.2015.05.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/29/2015] [Accepted: 05/14/2015] [Indexed: 01/07/2023]
Abstract
Chronic obstructive pulmonary disease (COPD) is associated with low aBMD as measured by DXA and altered microstructure as assessed by bone histomorphometry and microcomputed tomography. Knowledge of bone matrix mineralization is lacking in COPD. Using quantitative backscatter electron imaging (qBEI), we assessed cancellous (Cn.) and cortical (Ct.) bone mineralization density distribution (BMDD) in 19 postmenopausal women (62.1 ± 7.3 years of age) with COPD. Eight had sustained fragility fractures, and 13 had received treatment with inhaled glucocorticoids. The BMDD outcomes from the patients were compared with healthy reference data and were correlated with previous clinical and histomorphometric findings. In general, the BMDD outcomes for the patients were not significantly different from the reference data. Neither the subgroups of with or without fragility fractures or of who did or did not receive inhaled glucocorticoid treatment, showed differences in BMDD. However, subgroup comparison according to severity revealed 10% decreased cancellous mineralization heterogeneity (Cn.CaWidth) for the most severely affected compared with less affected patients (p=0.042) and compared with healthy premenopausal controls (p=0.021). BMDD parameters were highly correlated with histomorphometric cancellous bone volume (BV/TV) and formation indices: mean degree of mineralization (Cn.CaMean) versus BV/TV (r=0.58, p=0.009), and Cn.CaMean and Ct.CaMean versus bone formation rate (BFR/BS) (r=-0.71, p<0.001). In particular, those with lower BV/TV (<50th percentile) had significantly lower Cn.CaMean (p=0.037) and higher Cn.CaLow (p=0.020) compared with those with higher (>50th percentile) BV/TV. The normality in most of the BMDD parameters and bone formation rates as well as the significant correlations between them suggests unaffected mineralization processes in COPD. Our findings also indicate no significant negative effect of treatment with inhaled glucocorticoids on the bone mineralization pattern. However, the observed concomitant occurrence of relatively lower bone volumes with lower bone matrix mineralization will both contribute to the reduced aBMD in some patients with COPD.
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Affiliation(s)
- B M Misof
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria.
| | - P Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - V Jorgetti
- Department of Nephrology, School of Medicine, University of Sao Paulo, SP, Brazil
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - V Z C Borba
- Endocrine Division (SEMPR), Department of Internal Medicine, Clinical Hospital of the Federal University of Parana, Curitiba, PR, Brazil
| | - C L Boguszewski
- Endocrine Division (SEMPR), Department of Internal Medicine, Clinical Hospital of the Federal University of Parana, Curitiba, PR, Brazil
| | - A Cohen
- Department of Medicine, Division of Endocrinology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - E Shane
- Department of Medicine, Division of Endocrinology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - H Zhou
- Regional Bone Center, Helen Hayes Hospital, West Haverstraw, New York, USA
| | - D W Dempster
- Department of Pathology, Columbia University College of Physicians and Surgeons, New York, NY, USA; Regional Bone Center, Helen Hayes Hospital, West Haverstraw, New York, USA
| | - C A Moreira
- Endocrine Division (SEMPR), Department of Internal Medicine, Clinical Hospital of the Federal University of Parana, Curitiba, PR, Brazil
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Hassler N, Gamsjaeger S, Hofstetter B, Brozek W, Klaushofer K, Paschalis EP. Effects of long-term alendronate treatment on postmenopausal osteoporosis bone material properties. Osteoporos Int 2015; 26:339-52. [PMID: 25315260 DOI: 10.1007/s00198-014-2929-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/02/2014] [Indexed: 12/18/2022]
Abstract
UNLABELLED Raman microspectroscopic analysis of iliac crest from patients that were treated with alendronate (ALN) for 10 years revealed minimal, transient alterations in bone material properties confined to actively forming bone surfaces compared to patients that were on ALN for 5 years. These changes were not encountered in the bulk tissue. INTRODUCTION Alendronate (ALN) and other bisphosphonates (BPs) are the most widely prescribed therapy for postmenopausal osteoporosis. Despite their overall excellent safety record and efficacy in reducing fractures, questions have been raised regarding potential detrimental effects that may be related to prolonged bone turnover reduction, although no definite cause-effect relationship has been established to date. The purpose of the present study was to evaluate bone material properties in patients that were receiving ALN for 5 or 10 years. METHODS Raman microspectroscopic analysis was used to analyze iliac crest biopsies from postmenopausal women with osteoporosis who had been treated with ALN for 5 years and were then re-randomized to placebo (PBO, N = 14), 5 mg/day ALN (N = 10), or 10 mg/day ALN (N = 6) for another 5 years. The parameters monitored and expressed as a function of tissue age were (i) the mineral/matrix ratio (MM), (ii) the relative proteoglycan content (PG), (iii) the relative lipid content (LPD), (iv) the mineral maturity/crystallinity (MMC), and (v) the relative pyridinoline content (PYD). RESULTS The obtained data indicate that 10-year ALN use results in minimal, transient bone tissue composition changes compared to use for 5 years, confined to actively forming trabecular surfaces, implying potential differences in bone matrix maturation that nevertheless did not result in differences of these values in bulk tissue. CONCLUSIONS The data suggest that prolonged reduction in bone turnover during 10 years of therapy with ALN by itself is unlikely to be associated with adverse effects on bone material properties.
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Affiliation(s)
- N Hassler
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma CentreMeidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140, Vienna, Austria
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16
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Paschalis EP, Gamsjaeger S, Tatakis DN, Hassler N, Robins SP, Klaushofer K. Fourier transform Infrared spectroscopic characterization of mineralizing type I collagen enzymatic trivalent cross-links. Calcif Tissue Int 2015; 96:18-29. [PMID: 25424977 DOI: 10.1007/s00223-014-9933-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 11/15/2014] [Indexed: 01/10/2023]
Abstract
The most abundant protein of bone's organic matrix is collagen. One of its most important properties is its cross-linking pattern, which is responsible for the fibrillar matrices' mechanical properties such as tensile strength and viscoelasticity. We have previously described a spectroscopic method based on the resolution of the Amide I and II Fourier transform Infrared (FTIR) bands to their underlying constituent peaks, which allows the determination of divalent and pyridinoline (PYD) collagen cross-links in mineralized thin bone tissue sections with a spatial resolution of ~6.3 μm. In the present study, we used FTIR analysis of a series of biochemically characterized collagen peptides, as well as skin, dentin, and predentin, to examine the potential reasons underlying discrepancies between two different analytical methodologies specifically related to spectral processing. The results identified a novel distinct FTIR underlying peak at ~1,680 cm(-1), correlated with deoxypyridinoline (DPD) content. Furthermore, the two different methods of spectral resolution result in widely different results, while only the method employing well-established spectroscopic routines for spectral resolution provided biologically relevant results, confirming our earlier studies relating the area of the underlying 1,660 cm(-1) with PYD content. The results of the present study describe a new peak that may be used to determine DPD content, confirm our earlier report relating spectroscopic parameters to PYD content, and highlight the importance of the selected spectral resolution methodology.
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Affiliation(s)
- E P Paschalis
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Hanusch Krankenhaus, Heinrich Collin Str. 30, 1140, Vienna, Austria,
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17
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Gamsjaeger S, Mendelsohn R, Boskey AL, Gourion-Arsiquaud S, Klaushofer K, Paschalis EP. Vibrational spectroscopic imaging for the evaluation of matrix and mineral chemistry. Curr Osteoporos Rep 2014; 12:454-64. [PMID: 25240579 PMCID: PMC4638121 DOI: 10.1007/s11914-014-0238-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Metabolic bone diseases manifesting fragility fractures (such as osteoporosis) are routinely diagnosed based on bone mineral density (BMD) measurements, and the effect of various therapies also evaluated based on the same outcome. Although useful, it is well recognized that this metric does not fully account for either fracture incidence or the effect of various therapies on fracture incidence, thus, the emergence of bone quality as a contributing factor in the determination of bone strength. Infrared and Raman vibrational spectroscopic techniques are particularly well-suited for the determination of bone quality as they provide quantitative and qualitative information of the mineral and organic matrix bone components, simultaneously. Through the use of microspectroscopic techniques, this information is available in a spatially resolved manner, thus, the outcomes may be easily correlated with outcomes from techniques such as histology, histomorphometry, and nanoindentation, linking metabolic status with material properties.
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Affiliation(s)
- S. Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital, of WGKK and AUVA Trauma Centre Meidling, 1st Medical, Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | | | | | | | - K. Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital, of WGKK and AUVA Trauma Centre Meidling, 1st Medical, Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - E. P. Paschalis
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital, of WGKK and AUVA Trauma Centre Meidling, 1st Medical, Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria,
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18
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Hofstetter B, Gamsjaeger S, Varga F, Dobnig H, Stepan JJ, Petto H, Pavo I, Klaushofer K, Paschalis EP. Bone quality of the newest bone formed after two years of teriparatide therapy in patients who were previously treatment-naïve or on long-term alendronate therapy. Osteoporos Int 2014; 25:2709-19. [PMID: 25037600 DOI: 10.1007/s00198-014-2814-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 07/04/2014] [Indexed: 01/06/2023]
Abstract
UNLABELLED The results of the present study, involving analysis of biopsies from patients who received teriparatide for 2 years and were previously either treatment-naïve or on long-term alendronate therapy, suggest that prior alendronate use does not blunt the favorable effects of teriparatide on bone quality. INTRODUCTION Examine the effect of 2 years of teriparatide (TPTD) treatment on mineral and organic matrix properties of the newest formed bone in patients who were previously treatment-naïve (TN) or on long-term alendronate (ALN) therapy. METHODS Raman and Fourier transform infrared microspectroscopic analyses were used to determine the mineral/matrix (M/M) ratio, the relative proteoglycan (PG) content, and the mineral maturity/crystallinity (MMC; determined by three methods: carbonate content, full width at half height of the v 1 PO4 band [FWHH], and wavelength at maxima of the v 1 PO4 band), as well as collagen maturity (ratio of pyridinoline/divalent cross-links), in paired iliac crest biopsies at trabecular, endosteal, and osteonal surfaces of newly formed bone in postmenopausal osteoporotic women who were previously either TN (n = 16) or receiving long-term ALN treatment (n = 24). RESULTS Trabecular M/M ratio increased and matrix content decreased significantly in the ALN pretreated group. Collagen maturity decreased in both patient groups. Endosteal M/M ratio increased significantly in the TN group. Trabecular M/M ratio was higher at endpoint in the ALN pretreated group than in the TN group. Overall, no changes from baseline were observed in PG content, except that PG content was higher in the ALN pretreated group than in the TN group at endosteal surfaces at endpoint. The ability of TPTD treatment to reduce MMC in both patient groups and at the different bone surfaces depended on the measurement tool (relative carbonate content or wavelength at maxima of the v 1 PO4 band). None of the changes in MMC were different between the two patient groups. CONCLUSIONS The results suggest some favorable impact of TPTD on bone mineral and organic matrix properties of in situ forming bone in terms of increased initial mineralization and decreased MMC and collagen maturity. Moreover, prior long-term ALN administration may have only limited influence on these properties in bone newly formed after 2 years of TPTD treatment.
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Affiliation(s)
- B Hofstetter
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK, AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
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Gamsjaeger S, Hofstetter B, Fratzl-Zelman N, Roschger P, Roschger A, Fratzl P, Brozek W, Masic A, Misof BM, Glorieux FH, Klaushofer K, Rauch F, Paschalis EP. Pediatric reference Raman data for material characteristics of iliac trabecular bone. Bone 2014; 69:89-97. [PMID: 25245203 DOI: 10.1016/j.bone.2014.09.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 09/09/2014] [Accepted: 09/11/2014] [Indexed: 01/07/2023]
Abstract
Bone material characteristics are important contributors in the determination of bone strength. Raman spectroscopic analysis provides information on mineral/matrix ratio, mineral maturity/crystallinity, relative pyridinoline (Pyd) collagen cross-link content, relative proteoglycan content and relative lipid content. However, published reference data are available only for adults. The purpose of the present study was to establish reference data of Raman outcomes pertaining to bone quality in trabecular bone for children and young adults. To this end, tissue age defined Raman microspectroscopic analysis was performed on bone samples from 54 individuals between 1.5 and 23 years with no metabolic bone disease, which have been previously used to establish histomorphometric and bone mineralization density distribution reference values. Four distinct tissue ages, three well defined by the fluorescent double labels representing early stages of bone formation and tissue maturation (days 3, 12, 20 of tissue mineralization) and a fourth representing old mature tissue at the geometrical center of the trabeculae, were analyzed. In general, significant dependencies of the measured parameters on tissue age were found, while at any given tissue age, sex and subject age were not confounders. Specifically, mineral/matrix ratio, mineral maturity/crystallinity index and relative pyridinoline collagen cross-link content index increased by 485%, 20% and 14%, respectively between days 3 and 20. The relative proteoglycan content index was unchanged between days 3 and 20 but was elevated in the old tissue compared to young tissue by 121%. The relative lipid content decreased within days 3 to 20 by -22%. Thus, the method allows not only the monitoring of material characteristics at a specific tissue age but also the kinetics of tissue maturation as well. The established reference Raman database will serve as sensitive tool to diagnose disturbances in material characteristics of pediatric bone biopsy samples.
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Affiliation(s)
- S Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - B Hofstetter
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - N Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - P Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - A Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria; Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - P Fratzl
- Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - W Brozek
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - A Masic
- Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - B M Misof
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - F H Glorieux
- Genetics Unit, Shriners Hospital for Children and McGill University, Montreal, Quebec H3G 1A6, Canada
| | - K Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - F Rauch
- Genetics Unit, Shriners Hospital for Children and McGill University, Montreal, Quebec H3G 1A6, Canada
| | - E P Paschalis
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria.
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Misof BM, Dempster DW, Zhou H, Roschger P, Fratzl-Zelman N, Fratzl P, Silverberg SJ, Shane E, Cohen A, Stein E, Nickolas TL, Recker RR, Lappe J, Bilezikian JP, Klaushofer K. Relationship of bone mineralization density distribution (BMDD) in cortical and cancellous bone within the iliac crest of healthy premenopausal women. Calcif Tissue Int 2014; 95:332-9. [PMID: 25134800 PMCID: PMC4464772 DOI: 10.1007/s00223-014-9901-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 07/18/2014] [Indexed: 02/04/2023]
Abstract
Bone mineralization density distribution (BMDD) is an important determinant of bone mechanical properties. The most available skeletal site for access to the BMDD is the iliac crest. Compared to cancellous bone much less information on BMDD is available for cortical bone. Hence, we analyzed complete transiliac crest bone biopsy samples from premenopausal women (n = 73) aged 25-48 years, clinically classified as healthy, by quantitative backscattered electron imaging for cortical (Ct.) and cancellous (Cn.) BMDD. The Ct.BMDD was characterized by the arithmetic mean of the BMDD of the cortical plates. We found correlations between Ct. and Cn. BMDD variables with correlation coefficients r between 0.42 and 0.73 (all p < 0.001). Additionally to this synchronous behavior of cortical and cancellous compartments, we found that the heterogeneity of mineralization densities (Ct.Ca(Width)), as well as the cortical porosity (Ct.Po) was larger for a lower average degree of mineralization (Ct.Ca(Mean)). Moreover, Ct.Po correlated negatively with the percentage of highly mineralized bone areas (Ct.Ca(High)) and positively with the percentage of lowly mineralized bone areas (Ct.Ca(Low)). In conclusion, the correlation of cortical with cancellous BMDD in the iliac crest of the study cohort suggests coordinated regulation of bone turnover between both bone compartments. Only in a few cases, there was a difference in the degree of mineralization of >1wt % between both cortices suggesting a possible modeling situation. This normative dataset of healthy premenopausal women will provide a reference standard by which disease- and treatment-specific effects can be assessed at the level of cortical bone BMDD.
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Affiliation(s)
- B. M. Misof
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, First Medical Department, Hanusch Hospital, Heinrich Collin-Str. 30, 1140 Vienna, Austria
| | - D. W. Dempster
- Regional Bone Center, Helen Hayes Hospital, West Haverstraw, New York, NY, USA
- College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Hua Zhou
- Regional Bone Center, Helen Hayes Hospital, West Haverstraw, New York, NY, USA
| | - P. Roschger
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, First Medical Department, Hanusch Hospital, Heinrich Collin-Str. 30, 1140 Vienna, Austria
| | - N. Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, First Medical Department, Hanusch Hospital, Heinrich Collin-Str. 30, 1140 Vienna, Austria
| | - P. Fratzl
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - S. J. Silverberg
- Department of Medicine and Pathology, Columbia University, New York, NY, USA
| | - E. Shane
- Department of Medicine and Pathology, Columbia University, New York, NY, USA
| | - A. Cohen
- Department of Medicine and Pathology, Columbia University, New York, NY, USA
| | - E. Stein
- Department of Medicine and Pathology, Columbia University, New York, NY, USA
| | - T. L. Nickolas
- Department of Medicine and Pathology, Columbia University, New York, NY, USA
| | - R. R. Recker
- Creighton University Osteoporosis Research Center, Omaha, NE, USA
| | - J. Lappe
- Creighton University Osteoporosis Research Center, Omaha, NE, USA
| | - J. P. Bilezikian
- Department of Medicine and Pathology, Columbia University, New York, NY, USA
| | - K. Klaushofer
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, First Medical Department, Hanusch Hospital, Heinrich Collin-Str. 30, 1140 Vienna, Austria
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Al Kaissi A, Laccone F, Karner C, Ganger R, Klaushofer K, Grill F. [Hip dysplasia and spinal osteochondritis (Scheuermann's disease) in a girl with type II manifesting collagenopathy]. Orthopade 2014; 42:963-8. [PMID: 24013370 DOI: 10.1007/s00132-013-2182-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVES This paper describes the natural course of irritable hip pain associated with spinal rigidity and pain in the thoracic region with subsequent development of mild kyphosis in a girl with a mutation in the collagen 2 alpha 1 gene (type II collagenopathy). METHODS Phenotypic and genotypic characterization was carried out in a 14-year-old girl to identify the underlying pathology of severe irritable hip pain associated with thoracic spinal rigidity and pain. Detailed clinical examination, skeletal survey and genetic testing were performed accordingly. Bernese periacetabular osteotomy was used to alleviate pain and to improve the anatomical correlation of the acetabular and femoral heads. RESULTS Short stature associated with acetabulo-femoral dysplasia, spinal osteochondritis (Scheuermann's disease) and mild thoracic kyphosis were the most prominent abnormalities. Genetic analysis showed a heterozygous mutation in the collagen type II gene (COL2A1-c.1636G>A, p. G546S). A Bernese periacetabular osteotomy was performed to improve the clinical status of the patient. There was significant improvement in the extrusion index, the acetabular index and the lateral center-edge angle. CONCLUSIONS Hip dysplasia and Scheuermann's osteochondritis have never been reported in connection with a mutation in COL2A1 (collagenopathy type II). Awareness is needed for careful phenotypic and genotypic characterization in patients with irritable hip pain and spinal stiffness.
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Affiliation(s)
- A Al Kaissi
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital, Heinrich-Collin-Str. A-30, 1140, Wien, Österreich,
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Kerschan-Schindl K, Mikosch P, Obermayer-Pietsch B, Gasser R, Dimai HP, Fahrleitner-Pammer A, Dobnig H, Roschger P, Preisinger E, Klaushofer K, Resch H, Pietschmann P. Current Controversies in Clinical Management of Postmenopausal Osteoporosis. Exp Clin Endocrinol Diabetes 2014; 122:437-44. [DOI: 10.1055/s-0034-1374610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- K. Kerschan-Schindl
- Department of Physical Medicine & Rehabilitation, Medical University of Vienna
| | - P. Mikosch
- 1st Medical Department and Ludwig Boltzmann Institute of Osteology, Hanusch Hospital, Vienna
| | - B. Obermayer-Pietsch
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz
| | - R. Gasser
- Department of Internal Medicine I, Medical University of Innsbruck
| | - H.-P. Dimai
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz
| | - A. Fahrleitner-Pammer
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz
| | - H. Dobnig
- Schilddrüsen Endokrinologie Osteoporose Institut Dobnig GmbH, Graz
| | - P. Roschger
- 1st Medical Department and Ludwig Boltzmann Institute of Osteology, Hanusch Hospital, Vienna
| | - E. Preisinger
- Institute for Physical Medicine and Rehabilitation, Krankenhaus Hietzing mit Neurologischem Zentrum Rosenhügel, Vienna
| | - K. Klaushofer
- 1st Medical Department and Ludwig Boltzmann Institute of Osteology, Hanusch Hospital, Vienna
| | - H. Resch
- Department II Rheumatology/Osteology & Gastroenterology, St Vincent Hospital, Vienna
| | - P. Pietschmann
- Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna
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Rumpler M, Würger T, Roschger P, Zwettler E, Sturmlechner I, Altmann P, Fratzl P, Rogers MJ, Klaushofer K. Osteoclasts on bone and dentin in vitro: mechanism of trail formation and comparison of resorption behavior. Calcif Tissue Int 2013; 93:526-39. [PMID: 24022329 PMCID: PMC3827903 DOI: 10.1007/s00223-013-9786-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 08/20/2013] [Indexed: 11/26/2022]
Abstract
The main function of osteoclasts in vivo is the resorption of bone matrix, leaving behind typical resorption traces consisting of pits and trails. The mechanism of pit formation is well described, but less is known about trail formation. Pit-forming osteoclasts possess round actin rings. In this study we show that trail-forming osteoclasts have crescent-shaped actin rings and provide a model that describes the detailed mechanism. To generate a trail, the actin ring of the resorption organelle attaches with one side outside the existing trail margin. The other side of the ring attaches to the wall inside the trail, thus sealing that narrow part to be resorbed next (3–21 lm). This 3D configuration allows vertical resorption layer-by-layer from the surface to a depth in combination with horizontal cell movement. Thus, trails are not just traces of a horizontal translation of osteoclasts during resorption. Additionally, we compared osteoclastic resorption on bone and dentin since the latter is the most frequently used in vitro model and data are extrapolated to bone. Histomorphometric analyses revealed a material-dependent effect reflected by an 11-fold higher resorption area and a sevenfold higher number of pits per square centimeter on dentin compared to bone. An important material-independent aspect was reflected by comparable mean pit area (μm²) and podosome patterns. Hence, dentin promotes the generation of resorbing osteoclasts, but once resorption has started, it proceeds independently of material properties. Thus, dentin is a suitable model substrate for data acquisition as long as osteoclast generation is not part of the analyses.
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Affiliation(s)
- M. Rumpler
- 1st Medical Department, Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center, Hanusch-Krankenhaus, Pav. III, UG, Heinrich Collin Strasse 30, 1140 Vienna, Austria
| | - T. Würger
- 1st Medical Department, Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center, Hanusch-Krankenhaus, Pav. III, UG, Heinrich Collin Strasse 30, 1140 Vienna, Austria
| | - P. Roschger
- 1st Medical Department, Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center, Hanusch-Krankenhaus, Pav. III, UG, Heinrich Collin Strasse 30, 1140 Vienna, Austria
| | - E. Zwettler
- 1st Medical Department, Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center, Hanusch-Krankenhaus, Pav. III, UG, Heinrich Collin Strasse 30, 1140 Vienna, Austria
| | - I. Sturmlechner
- 1st Medical Department, Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center, Hanusch-Krankenhaus, Pav. III, UG, Heinrich Collin Strasse 30, 1140 Vienna, Austria
| | - P. Altmann
- 1st Medical Department, Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center, Hanusch-Krankenhaus, Pav. III, UG, Heinrich Collin Strasse 30, 1140 Vienna, Austria
| | - P. Fratzl
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - M. J. Rogers
- The Garvan Institute of Medical Research, Darlinghurst, NSW Australia
| | - K. Klaushofer
- 1st Medical Department, Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center, Hanusch-Krankenhaus, Pav. III, UG, Heinrich Collin Strasse 30, 1140 Vienna, Austria
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van der Eerden BCJ, Oei L, Roschger P, Fratzl-Zelman N, Hoenderop JGJ, van Schoor NM, Pettersson-Kymmer U, Schreuders-Koedam M, Uitterlinden AG, Hofman A, Suzuki M, Klaushofer K, Ohlsson C, Lips PJA, Rivadeneira F, Bindels RJM, van Leeuwen JPTM. TRPV4 deficiency causes sexual dimorphism in bone metabolism and osteoporotic fracture risk. Bone 2013; 57:443-54. [PMID: 24084385 DOI: 10.1016/j.bone.2013.09.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 08/16/2013] [Accepted: 09/16/2013] [Indexed: 11/20/2022]
Abstract
We explored the role of transient receptor potential vanilloid 4 (TRPV4) in murine bone metabolism and association of TRPV4 gene variants with fractures in humans. Urinary and histomorphometrical analyses demonstrated reduced osteoclast activity and numbers in male Trpv4(-/-) mice, which was confirmed in bone marrow-derived osteoclast cultures. Osteoblasts and bone formation as shown by serum procollagen type 1 amino-terminal propeptide and histomorphometry, including osteoid surface, osteoblast and osteocyte numbers were not affected in vivo. Nevertheless, osteoblast differentiation was enhanced in Trpv4(-/-) bone marrow cultures. Cortical and trabecular bone mass was 20% increased in male Trpv4(-/-) mice, compared to sex-matched wild type (Trpv4(+/+)) mice. However, at the same time intracortical porosity was increased and bone matrix mineralization was reduced. Together, these lead to a maximum load, stiffness and work to failure of the femoral bone, which were not different compared to Trpv4(+/+) mice, while the bone material was less resistant to stress and less elastic. The differential impacts on these determinants of bone strength were likely responsible for the lack of any changes in whole bone strength in the Trpv4(-/-) mice. None of these skeletal parameters were affected in female Trpv4(-/-) mice. The T-allele of rs1861809 SNP in the TRPV4 locus was associated with a 30% increased risk (95% CI: 1.1-1.6; p=0.013) for non-vertebral fracture risk in men, but not in women, in the Rotterdam Study. Meta-analyses with the population-based LASA study confirmed the association with non-vertebral fractures in men. This was lost when the non-population-based studies Mr. OS and UFO were included. In conclusion, TRPV4 is a male-specific regulator of bone metabolism, a determinant of bone strength, and a potential risk predictor for fractures through regulation of bone matrix mineralization and intra-cortical porosity. This identifies TRPV4 as a unique sexually dimorphic therapeutic and/or diagnostic candidate for osteoporosis.
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Roschger A, Hofstaetter JG, Pemmer B, Zoeger N, Wobrauschek P, Falkenberg G, Simon R, Berzlanovich A, Thaler HW, Roschger P, Klaushofer K, Streli C. Differential accumulation of lead and zinc in double-tidemarks of articular cartilage. Osteoarthritis Cartilage 2013; 21:1707-15. [PMID: 23835117 DOI: 10.1016/j.joca.2013.06.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 06/26/2013] [Accepted: 06/27/2013] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Long-term exposure to increased lead (Pb) concentrations is associated with several chronic diseases. The divalent cation zinc (Zn) is essential for numerous enzymes. In a recent study we found remarkably elevated concentrations of Pb and Zn in the tidemark (TM), which is the mineralization front of human articular cartilage. OBJECTIVE Duplication or multiplication of TMs occurs with advancing age or degeneration. We hypothesized that trace elements accumulate in TMs as a function of time. Thus, in cases of double TMs, the deep (older) TM should contain higher Pb and Zn concentrations than the superficial (younger) TM. DESIGN Undecalcified tissue from articular cartilage and subchondral bone of femoral heads and patellae was examined by synchrotron radiation induced confocal micro X-ray fluorescence analysis and by quantitative backscattered electron imaging to determine the local distribution of Ca, Zn, and Pb in this tissue. RESULTS The evaluation of X-ray fluorescence intensities in double TMs revealed in average a 2.6-fold higher Pb level in the deep TM compared to the superficial TM while Zn concentrations were similar. Pb and Zn contents were significantly enhanced in the deep TM (Pb: 35-fold, Zn: five-fold) and in the superficial TM (Pb: 12-fold, Zn: five-fold) compared to the bone level. CONCLUSION For the first time a differential accumulation of Pb and Zn is documented in regions with double TMs revealing various timescales for the accumulation of these elements. Increased amounts of Pb are present in the TMs (up to the 62-fold of the bone level) featuring a potential source of internal Pb release if the TM region is destroyed.
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Affiliation(s)
- A Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria; Atominstitut, Technische Universitaet Wien, Stationallee 2, 1020 Vienna, Austria.
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Pemmer B, Roschger A, Wastl A, Hofstaetter J, Wobrauschek P, Simon R, Thaler H, Roschger P, Klaushofer K, Streli C. Spatial distribution of the trace elements zinc, strontium and lead in human bone tissue. Bone 2013; 57:184-93. [PMID: 23932972 PMCID: PMC3807669 DOI: 10.1016/j.bone.2013.07.038] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/25/2013] [Accepted: 07/30/2013] [Indexed: 11/15/2022]
Abstract
Trace elements are chemical elements in minute quantities, which are known to accumulate in the bone. Cortical and trabecular bones consist of bone structural units (BSUs) such as osteons and bone packets of different mineral content and are separated by cement lines. Previous studies investigating trace elements in bone lacked resolution and therefore very little is known about the local concentration of zinc (Zn), strontium (Sr) and lead (Pb) in BSUs of human bone. We used synchrotron radiation induced micro X-ray fluorescence analysis (SR μ-XRF) in combination with quantitative backscattered electron imaging (qBEI) to determine the distribution and accumulation of Zn, Sr, and Pb in human bone tissue. Fourteen human bone samples (10 femoral necks and 4 femoral heads) from individuals with osteoporotic femoral neck fractures as well as from healthy individuals were analyzed. Fluorescence intensity maps were matched with BE images and correlated with calcium (Ca) content. We found that Zn and Pb had significantly increased levels in the cement lines of all samples compared to the surrounding mineralized bone matrix. Pb and Sr levels were found to be correlated with the degree of mineralization. Interestingly, Zn intensities had no correlation with Ca levels. We have shown for the first time that there is a differential accumulation of the trace elements Zn, Pb and Sr in BSUs of human bone indicating different mechanisms of accumulation.
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Affiliation(s)
- B. Pemmer
- Atominstitut, Technische Universitaet Wien, Stadionallee 2, 1020 Vienna, Austria
- Corresponding author at: TU Wien, Atominstitut, Radiation physics, Stadionallee 2, 1020 Vienna, Austria. Fax: + 43 1 58801 14199.
| | - A. Roschger
- Atominstitut, Technische Universitaet Wien, Stadionallee 2, 1020 Vienna, Austria
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - A. Wastl
- Atominstitut, Technische Universitaet Wien, Stadionallee 2, 1020 Vienna, Austria
| | - J.G. Hofstaetter
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
- 2nd Department, Orthopaedic Hospital Vienna-Speising, Austria
| | - P. Wobrauschek
- Atominstitut, Technische Universitaet Wien, Stadionallee 2, 1020 Vienna, Austria
| | - R. Simon
- Karlsruhe Institute of Technology, Institute for Synchrotron Radiation, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | | | - P. Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - K. Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - C. Streli
- Atominstitut, Technische Universitaet Wien, Stadionallee 2, 1020 Vienna, Austria
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27
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Kerschan-Schindl K, Haschka J, Obermayer-Pietsch B, Gasser RW, Dimai HP, Fahrleitner-Pammer A, Dobnig H, Roschger P, Preisinger E, Klaushofer K, Resch H, Pietschmann P. How long should women with postmenopausal osteoporosis be treated with a bisphosphonate? Horm Metab Res 2013; 45:621-8. [PMID: 23757119 DOI: 10.1055/s-0033-1345207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Bisphosphonates are very frequently prescribed to women suffering from postmenopausal osteoporosis with or without fragility fractures. The present review was aimed to update the available information on the most efficient treatment duration. Studies on bisphosphonate treatment duration were identified by Medline up to January 2013. Bisphosphonates are very effective in the short as well as in the medium-term. However, the optimal duration of use has not been determined yet. Therefore, this review summarizes the long-term effects of bisphosphonates on surrogate parameters of fracture prevention, bone mineral density measurements, and bone turnover markers. An initial treatment period of 3-5 years is recommended. Then, the patient has to be re-evaluated for fracture risk, which depends on fracture status as well as on other health issues. Beyond that, life style factors such as regular physical activity as well as a sufficient intake of calcium and vitamin D or, if necessary supplementation of calcium and/or vitamin D play an essential part in fracture prevention.
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Affiliation(s)
- K Kerschan-Schindl
- Department of Physical Medicine & Rehabilitation, Medical University of Vienna, Austria.
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Gamsjaeger S, Hofstetter B, Zwettler E, Recker R, Gasser JA, Eriksen EF, Klaushofer K, Paschalis EP. Effects of 3 years treatment with once-yearly zoledronic acid on the kinetics of bone matrix maturation in osteoporotic patients. Osteoporos Int 2013; 24:339-47. [PMID: 23229465 DOI: 10.1007/s00198-012-2202-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 09/26/2012] [Indexed: 11/29/2022]
Abstract
UNLABELLED Once-yearly administration of intravenous zoledronic acid for 3 years in humans affects the kinetics of matrix filling in by mineral, independent of bone turnover. INTRODUCTION Yearly 5-mg infusions of zoledronic acid (ZOL) for 3 years have shown pronounced antifracture efficacy. The purpose of the present study was to test whether ZOL affects the kinetics of forming bone material properties maturation. METHODS Iliac crest biopsies from the HORIZON-PFT clinical trial were analyzed by Raman microspectroscopy in actively bone-forming surfaces as a function of tissue age in trabecular and osteonal bone, to determine ZOL's effect on bone material quality indices maturation kinetics. RESULTS Mineral/matrix ratio increased in both groups as a function of tissue age, at both osteonal- and trabecular-forming surfaces; ZOL exhibiting the greatest increase in the trabecular surfaces only. The proteoglycan content showed a dependency on tissue age in both trabecular and osteonal surfaces, with ZOL exhibiting lower values in the tissue age 8-22 days in the trabecular surfaces. Mineral crystallinity (crystallite length and thickness) showed a dependence on tissue age, with ZOL exhibiting lower crystallite length compared with placebo only in the 8- to 22-day-old tissue at trabecular surfaces, while crystal thickness was lower in the 1- to 5-day-old tissue at both osteonal and trabecular surfaces. CONCLUSIONS The results of the present study suggest that once-yearly administration of intravenous ZOL for 3 years in humans does not exert any adverse effects on the evolution of bone material properties at actively forming osteonal and trabecular surfaces, while it may have a beneficial effect on the progression of the mineral-to-matrix ratio and mineral maturity bone quality indices.
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Affiliation(s)
- S Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, 1140, Vienna, Austria.
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Thaler R, Spitzer S, Karlic H, Berger C, Klaushofer K, Varga F. Ibandronate increases the expression of the pro-apoptotic gene FAS by epigenetic mechanisms in tumor cells. Biochem Pharmacol 2012; 85:173-85. [PMID: 23103563 PMCID: PMC3557391 DOI: 10.1016/j.bcp.2012.10.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 10/16/2012] [Accepted: 10/16/2012] [Indexed: 12/13/2022]
Abstract
There is growing evidence that aminobisphosphonates like ibandronate show anticancer activity by an unknown mechanism. Biochemically, they prevent posttranslational isoprenylation of small GTPases, thus inhibiting their activity. In tumor cells, activated RAS-GTPase, the founding member of the gene family, down-regulates the expression of the pro-apoptotic gene FAS via epigenetic DNA-methylation by DNMT1. We compared ibandronate treatment in neoplastic human U-2 osteosarcoma and in mouse CCL-51 breast cancer cells as well as in the immortalized non-neoplastic MC3T3-E1 osteoblastic cells. Ibandronate attenuated cell proliferation in all cell lines tested. In the neoplastic cells we found up-regulation of caspases suggesting apoptosis. Further we found stimulation of FAS-expression as a result of epigenetic DNA demethylation that was due to down-regulation of DNMT1, which was rescued by re-isoprenylation by both geranylgeranyl-pyrophosphate and farnesylpyrophosphate. In contrast, ibandronate did not affect FAS and DNMT1 expression in MC3T3-E1 non-neoplastic cells. Data suggest that bisphosphonates via modulation of the activity of small-GTPases induce apoptosis in neoplastic cells by DNA-CpG-demethylation and stimulation of FAS-expression. In conclusion the shown epigenetic mechanism underlying the anti-neoplastic activity of farnesyl-transferase-inhibition, also explains the clinical success of other drugs, which target this pathway.
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Affiliation(s)
- R. Thaler
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - S. Spitzer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - H. Karlic
- Ludwig Boltzmann Cluster Oncology and Institute for Leukemia Research and Hematology, Hanusch Hospital, Vienna, Austria
| | - C. Berger
- Department of Orthopedics, SMZ-OST, Danube Hospital, Vienna, Austria
| | - K. Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - F. Varga
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
- Corresponding author at: Ludwig Boltzmann Institute of Osteology, 1st Medical Department, Hanusch Hospital, Heinrich Collin-Str. 30, A-1140 Vienna, Austria. Tel.: +43 1 91021 86933; fax: +43 1 91021 86929.
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Paschalis E, Tatakis D, Robins S, Fratzl P, Manjubala I, Zoehrer R, Gamsjaeger S, Buchinger B, Roschger A, Phipps R, Boskey A, Dall'Ara E, Varga P, Zysset P, Klaushofer K, Roschger P. Lathyrism-induced alterations in collagen cross-links influence the mechanical properties of bone material without affecting the mineral. Bone 2011; 49:1232-41. [PMID: 21920485 PMCID: PMC3229977 DOI: 10.1016/j.bone.2011.08.027] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 08/24/2011] [Accepted: 08/26/2011] [Indexed: 12/17/2022]
Abstract
In the present study a rat animal model of lathyrism was employed to decipher whether anatomically confined alterations in collagen cross-links are sufficient to influence the mechanical properties of whole bone. Animal experiments were performed under an ethics committee approved protocol. Sixty-four female (47 day old) rats of equivalent weights were divided into four groups (16 per group): Controls were fed a semi-synthetic diet containing 0.6% calcium and 0.6% phosphorus for 2 or 4 weeks and β-APN treated animals were fed additionally with β-aminopropionitrile (0.1% dry weight). At the end of this period the rats in the four groups were sacrificed, and L2-L6 vertebra were collected. Collagen cross-links were determined by both biochemical and spectroscopic (Fourier transform infrared imaging (FTIRI)) analyses. Mineral content and distribution (BMDD) were determined by quantitative backscattered electron imaging (qBEI), and mineral maturity/crystallinity by FTIRI techniques. Micro-CT was used to describe the architectural properties. Mechanical performance of whole bone as well as of bone matrix material was tested by vertebral compression tests and by nano-indentation, respectively. The data of the present study indicate that β-APN treatment changed whole vertebra properties compared to non-treated rats, including collagen cross-links pattern, trabecular bone volume to tissue ratio and trabecular thickness, which were all decreased (p<0.05). Further, compression tests revealed a significant negative impact of β-APN treatment on maximal force to failure and energy to failure, while stiffness was not influenced. Bone mineral density distribution (BMDD) was not altered either. At the material level, β-APN treated rats exhibited increased Pyd/Divalent cross-link ratios in areas confined to a newly formed bone. Moreover, nano-indentation experiments showed that the E-modulus and hardness were reduced only in newly formed bone areas under the influence of β-APN, despite a similar mineral content. In conclusion the results emphasize the pivotal role of collagen cross-links in the determination of bone quality and mechanical integrity. However, in this rat animal model of lathyrism, the coupled alterations of tissue structural properties make it difficult to weigh the contribution of the anatomically confined material changes to the overall mechanical performance of whole bone. Interestingly, the collagen cross-link ratio in bone forming areas had the same profile as seen in actively bone forming trabecular surfaces in human iliac crest biopsies of osteoporotic patients.
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Affiliation(s)
- E.P. Paschalis
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
- Corresponding author at: Ludwig Boltzmann Institute of Osteology, Hanusch Krankenhaus, Heinrich Collin Str. 30, A-1140 Vienna, Austria.
| | - D.N. Tatakis
- Division of Periodontology, The Ohio State University, Columbus, OH, USA
- Visiting Professor, King Saud University, Riyadh, Saudi Arabia
| | - S. Robins
- Matrix Biochemistry, Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, Scotland, UK
| | - P. Fratzl
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Research Campus Golm, Potsdam, Germany
| | - I. Manjubala
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Research Campus Golm, Potsdam, Germany
| | - R. Zoehrer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - S. Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - B. Buchinger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - A. Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - R. Phipps
- Dept. of Pharmacology, Husson University, ME, USA
| | - A.L. Boskey
- Hospital for Special Surgery, New York, NY, USA
| | - E. Dall'Ara
- Institut für Leichtbau und Struktur-Biomechanik, TU Wien, Vienna, Austria
| | - P. Varga
- Institut für Leichtbau und Struktur-Biomechanik, TU Wien, Vienna, Austria
| | - P. Zysset
- Institut für Leichtbau und Struktur-Biomechanik, TU Wien, Vienna, Austria
| | - K. Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
| | - P. Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Heinrich Collin Str. 30, A-1140 Vienna, Austria
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Al Kaissi A, Kalchhauser G, Klaushofer K, Handlbauer A, Grill F. Distinctive vertebral abnormalities in a patient with VACTERL association. ROFO-FORTSCHR RONTG 2011; 184:62-5. [PMID: 22033847 DOI: 10.1055/s-0031-1281796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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Thaler R, Rumpler M, Spitzer S, Klaushofer K, Varga F. Mospd1, a new player in mesenchymal versus epidermal cell differentiation. J Cell Physiol 2011; 226:2505-15. [PMID: 21792907 DOI: 10.1002/jcp.22595] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mospd1 codes for a small protein with unknown physiological function, which is part of a family of genes, including Mospd2 and Mospd3, defined by the presence of the major sperm protein domain and two transmembrane domains. This work characterizes the Mospd1 gene, the intracellular location of the protein and its expression in different mouse tissues and mesenchymal cell lines during differentiation. The role of Mospd1 in mesenchymal cellular differentiation was studied by siRNA knockdown experiments in mouse osteoblastic MC3T3-E1 cells. Transfection experiments of the targeted cDNA show MOSPD1 located in the endoplasmatic reticulum and in the Golgi apparatus. Removal of the last exon of the gene resulted in localization of the protein in the nucleus, which was attributed to a nuclear export sequence in the N-terminal part. In mouse tissues the gene was generally strongly expressed while mesenchymal tissues showed the highest expression. In mesenchymal cell lines Mospd1 mRNA was higher expressed in cells with advanced differentiation status. In osteoblastic, myoblastic, and adipocytic cell lines Mospd1 was up-regulated during differentiation. Genome-wide gene expression analysis after knockdown of Mospd1 by siRNA in MC3T3-E1 cells revealed a shift in the gene expression pattern from mesenchymal to epithelial genes featuring up-regulation of the epithelial cadherin Cdh1 and down-regulation of its inhibitors Snail1 and 2 and the mesenchymal cadherin Cdh11, suggesting a mesenchymal to epithelial transition. From these data we conclude that Mospd1 plays a pivotal role in the developmental regulation at the switch between mesenchymal and epithelial cells.
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Affiliation(s)
- R Thaler
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, Vienna, Austria
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Weber M, Schoeberl T, Roschger P, Klaushofer K, Fratzl P. Relating Local Bone Stiffness and Calcium Content by Combined Nanoindentation and Backscattered Electron Imaging. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-874-l5.11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractBone is a hierarchically structured mineral-organic composite material that has to bear static and dynamic mechanical loads applied by body weight and locomotion. Bone mechanical properties are influenced by a number of factors, depending on the particular hierarchical levels. The high stiffness of bone material is mainly achieved by reinforcement with calcium phosphate mineral platelets. A model for this elementary structure level consists of an arrangement of staggered mineral bricks, embedded in collagen matrix, which provides both stiffness and toughness. The mechanical properties depend on the amount, shape and arrangement of the mineral particles but also on the properties of the collagen-rich matrix.One of the difficulties in assessing the properties of hierarchical structures is the inherent inhomogeneity of the tissue: Parameters such as stiffness or calcium content vary throughout a bone section. Such type of investigations becomes more meaningful by a combination of two complementary methods e.g. quantitative backscattered electron imaging (qBEI) and nanoindentation. The local Ca-content, representing the degree of the mineralization, is extracted from the qBEI measurements, whereas the local mechanical properties, elastic modulus and hardness, are measured by nanoindentation, a miniaturized hardness testing using a small diamond tip. The measured correlations between local Ca-content and mechanical strength help, for example, to verify biomechanical models based on the nanocomposite structure of bone. They may also shed new light on bone diseases such as osteoporosis or osteogenesis imperfecta.
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Varga F, Rumpler M, Zoehrer R, Turecek C, Spitzer S, Thaler R, Paschalis E, Klaushofer K. T3 affects expression of collagen I and collagen cross-linking in bone cell cultures. Biochem Biophys Res Commun 2010; 402:180-5. [PMID: 20707983 PMCID: PMC3025330 DOI: 10.1016/j.bbrc.2010.08.022] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 08/06/2010] [Indexed: 11/16/2022]
Abstract
Thyroid hormones (T3, T4) have a broad range of effects on bone, however, its role in determining the quality of bone matrix is poorly understood. In-vitro, the immortalized mouse osteoblast-like cell line MC3T3-E1 forms a tissue like structure, consisting of several cell layers, whose formation is affected by T3 significantly. In this culture system, we investigated the effects of T3 on cell multiplication, collagen synthesis, expression of genes related to the collagen cross-linking process and on the formation of cross-links. T3 compared to controls modulated cell multiplication, up-regulated collagen synthesis time and dose dependently, and stimulated protein synthesis. T3 increased mRNA expressions of procollagen-lysine-1,2-oxoglutarate 5-dioxygenase 2 (Plod2) and of lysyloxidase (Lox), both genes involved in post-translational modification of collagen. Moreover, it stimulated mRNA expression of bone morphogenetic protein 1 (Bmp1), the processing enzyme of the lysyloxidase-precursor and of procollagen. An increase in the collagen cross-link-ratio Pyr/deDHLNL indicates, that T3 modulated cross-link maturation in the MC3T3-E1 culture system. These results demonstrate that T3 directly regulates collagen synthesis and collagen cross-linking by up-regulating gene expression of the specific cross-link related enzymes, and underlines the importance of a well-balanced concentration of thyroid hormones for maintenance of bone quality.
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Affiliation(s)
- F. Varga
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, Vienna, Austria
| | - M. Rumpler
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, Vienna, Austria
| | - R. Zoehrer
- Flinders University, School of Chemistry and Physics, Australia
| | - C. Turecek
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, Vienna, Austria
| | - S. Spitzer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, Vienna, Austria
| | - R. Thaler
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, Vienna, Austria
| | - E.P. Paschalis
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, Vienna, Austria
| | - K. Klaushofer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, Vienna, Austria
- Corresponding author. Address: Ludwig Boltzmann Institute of Osteology, 4th Medical Department, Hanusch Hospital, Heinrich Collin-Str. 30, A-1140 Vienna, Austria. Fax: +43 1 91021 86929.
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Gamsjaeger S, Masic A, Roschger P, Kazanci M, Dunlop JWC, Klaushofer K, Paschalis EP, Fratzl P. Cortical bone composition and orientation as a function of animal and tissue age in mice by Raman spectroscopy. Bone 2010; 47:392-9. [PMID: 20450992 DOI: 10.1016/j.bone.2010.04.608] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 04/15/2010] [Accepted: 04/26/2010] [Indexed: 11/24/2022]
Abstract
Important aspects of bone tissue quality include the physicochemical properties of its main constituents, the organic matrix and the mineral crystals. One of the most commonly reported measurements of Raman analysis of bone is the mineral to matrix ratio, obtained from the ratio of the integrated areas of any of the phosphate and amide peaks which depend on both tissue organization and composition. Cube-like samples of normal mouse cortical bone taken from the diaphysis and metaphysis of the femur were investigated within different age groups (2, 4, 8 and 12 weeks) by Raman microspectroscopy. Anatomically identical bone in both longitudinal and transverse directions was analyzed, enabling the discrimination between orientation and composition changes both as a function of animal age, and tissue age within the same animal. The results of the present study indicate that there is a parallel evolution of both orientation and chemical composition as a function of animal age, as well as tissue age within the same specimen. Our tissue age modified ratio of the carbonate to phosphate Raman peaks suggests that the bone mineral crystallite maturity remains relatively constant with animal age. Comparisons of polarized and depolarized experiments in the transversal plane of the diaphysis show a lack of orientation effects as a function of tissue age within the same animal, but exhibit differences as a function of animal age. In the metaphysis, the orientation effect is evident too, albeit less pronounced. This is most likely due to either the age difference between the two tissues within the same specimen in the long bone axis, as metaphyseal bone is generally younger than diaphyseal, or the more random orientation of the tissue collagen itself.
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Affiliation(s)
- Sonja Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 4th Medical Department, Hanusch Hospital, Vienna, Austria
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Fratzl-Zelman N, Morello R, Lee B, Rauch F, Glorieux FH, Misof BM, Klaushofer K, Roschger P. CRTAP deficiency leads to abnormally high bone matrix mineralization in a murine model and in children with osteogenesis imperfecta type VII. Bone 2010; 46:820-6. [PMID: 19895918 PMCID: PMC2825377 DOI: 10.1016/j.bone.2009.10.037] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 10/07/2009] [Accepted: 10/27/2009] [Indexed: 11/23/2022]
Abstract
Cartilage-associated protein (CRTAP) is an essential cofactor for the proper post-translational chain modification and collagen folding. CRTAP mutations lead mice (Crtap-/- mice) and humans (OI type VII) to a severe/lethal osteochondrodystrophy; patients have fractures at birth, deformities of the lower extremities and impaired growth. The consequences of CRTAP deficiency on intrinsic bone material properties are still unknown. In the present study we evaluated bone quality based on quantitative backscattered electron imaging (qBEI) to assess bone mineralization density distribution (BMDD) in femurs from 12 weeks old Crtap-/- mice and transiliac bone biopsies from 4 children with hypomorphic mutations and having residual CRTAP expression. The analyses revealed in the bone matrix of Crtap-/- animals and OI type VII patients a significant increase in mean (CaMean) and most frequent mineral concentration (CaPeak) compared to wild-type littermates and control children, respectively. The heterogeneity of mineralization (CaWidth) was reduced in Crtap-/- mice but normal in OI type VII patients. The fraction of highly mineralized bone matrix (CaHigh) was remarkably increased in the patients: cancellous bone from 2.1 to 3.7 times and cortical bone from 7.6 to 25.5 times, associated with an increased persistence of primary bone. In conclusion, the BMDD data show that CRTAP deficiency results in a shift towards higher mineral content of the bone matrix similar to classical OI with collagen gene mutations. Our data further suggest altered mineralization kinetics resulting ultimately in an overall elevated tissue mineralization density. Finally, in OI type VII patients the increased portion of primary bone is most likely reflecting a disturbed bone development.
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Affiliation(s)
- N Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital, Vienna, Austria.
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Al Kaissi A, Roschger P, Nawrot-Wawrzyniak K, Krebs A, Grill F, Klaushofer K. Evidence of reduced bone turnover and disturbed mineralization process in a boy with Stickler syndrome. Calcif Tissue Int 2010; 86:126-31. [PMID: 20012270 DOI: 10.1007/s00223-009-9324-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 11/05/2009] [Indexed: 11/25/2022]
Abstract
We describe a tall-statured 14-year-old boy who illustrated the full phenotypic and radiographic features of Stickler syndrome type I. A bone biopsy showed evidence of reduced bone mass and bone turnover, such as reduced BV/TV (-43%), TbTh (-29%), and OS/BS (-48%), Ob.S/BS (-27%), and Oc/BS (-47%) compared to "age-matched" controls. Moreover, there was evidence that the mineralization process was severely disturbed. Quantitative backscattered electron imaging revealed that the bone mineralization density distribution (BMDD) of cancellous (Cn) as well as cortical (Ct) bone was shifted toward lower mineralization compared to a young control reference cohort. BMDD parameters of mean degree of mineralization, Cn Ca (-9.8%) and Ct Ca (-18.0%), were dramatically decreased. To the best of our knowledge this is the first clinical report describing bone biopsy findings in a boy with Stickler syndrome. Such a severe undermineralization of bone matrix might essentially contribute to the compromised mechanical competence of the skeleton found in this patient.
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Affiliation(s)
- A Al Kaissi
- Ludwig-Boltzmann Institute of Osteology, Hanusch Hospital of WGKK, 4th Medical Department, Vienna, Austria.
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Fratzl-Zelman N, Roschger P, Gourrier A, Weber M, Misof BM, Loveridge N, Reeve J, Klaushofer K, Fratzl P. Combination of nanoindentation and quantitative backscattered electron imaging revealed altered bone material properties associated with femoral neck fragility. Calcif Tissue Int 2009; 85:335-43. [PMID: 19756347 PMCID: PMC2759010 DOI: 10.1007/s00223-009-9289-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 08/02/2009] [Indexed: 02/08/2023]
Abstract
Osteoporotic fragility fractures were hypothesized to be related to changes in bone material properties and not solely to reduction in bone mass. We studied cortical bone from the superior and inferior sectors of whole femoral neck sections from five female osteoporotic hip fracture cases (74-92 years) and five nonfractured controls (75-88 years). The typical calcium content (Ca(Peak)) and the mineral particle thickness parameter (T) were mapped in large areas of the superior and inferior regions using quantitative backscattered electron imaging (qBEI) and scanning small-angle X-ray scattering, respectively. Additionally, indentation modulus (E) and hardness (H) (determined by nanoindentation) were compared at the local level to the mineral content (Ca(Ind)) at the indent positions (obtained from qBEI). Ca(Peak) (-2.2%, P = 0.002), Ca(Ind) (-1.8%, P = 0.048), E (-5.6%, P = 0.040), and H (-6.0%, P = 0.016) were significantly lower for the superior compared to the inferior region. Interestingly, Ca(Peak) as well as Ca(Ind) were also lower (-2.6%, P = 0.006, and -3.7%, P = 0.002, respectively) in fracture cases compared to controls, while E and H did not show any significant reduction. T values were in the normal range, independent of region (P = 0.181) or fracture status (P = 0.551). In conclusion, it appears that the observed femoral neck fragility is associated with a reduced mineral content, which was not accompanied by a reduction in stiffness and hardness of the bone material. This pilot study suggests that a stiffening process in the organic matrix component contributes to bone fragility independently of mineral content.
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Affiliation(s)
- N. Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, 1140 Vienna, Austria
| | - P. Roschger
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, 1140 Vienna, Austria
| | - A. Gourrier
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
- Laboratoire de Physique des Solides, Université Paris-Sud, Bat. 510, 91405 Orsay cedex, France
| | - M. Weber
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
- Erich Schmid Institute of Materials Science, Austrian Academy of Sciences and Institute of Metal Physics, University of Leoben, 8700 Leoben, Austria
| | - B. M. Misof
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, 1140 Vienna, Austria
- Ludwig Boltzmann Institute of Osteology, UKH Meidling, Kundratstrasse 37, A-1120 Vienna, Austria
| | - N. Loveridge
- Bone Research Division, Department of Medicine, University of Cambridge, Cambridge, CB2 2QQ UK
| | - J. Reeve
- Bone Research Division, Department of Medicine, University of Cambridge, Cambridge, CB2 2QQ UK
| | - K. Klaushofer
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, 1140 Vienna, Austria
| | - P. Fratzl
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
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Fratzl-Zelman N, Roschger P, Misof BM, Pfeffer S, Glorieux FH, Klaushofer K, Rauch F. Normative data on mineralization density distribution in iliac bone biopsies of children, adolescents and young adults. Bone 2009; 44:1043-8. [PMID: 19268565 DOI: 10.1016/j.bone.2009.02.021] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 02/15/2009] [Accepted: 02/19/2009] [Indexed: 11/19/2022]
Abstract
Bone mineralization density distribution (BMDD) as assessed by quantitative backscattered electron imaging (qBEI) in iliac crest bone biopsies has become in the last years a powerful diagnostic tool to evaluate the effect of metabolic bone diseases and/or therapeutic interventions on the mineralization status of the bone material. However until now, normative reference data are only available for adults. The aim of the present study is to close this gap and establish normative data from children and compare them with reference BMDD data of adults. qBEI analyses were performed on bone samples from 54 individuals between 1.5 and 23 years without metabolic bone diseases, which were previously used as study population to establish normative histomorphometric standards. In the trabecular compartment, none of the BMDD parameters showed a significant correlation with age. The BMDD was shifted towards lower mineralization density (CaMean -5.6%, p<0.0001; CaPeak -5.6%, p<0.0001; CaLow +39.0% p<0.001; CaHigh -80.7%, p<0.001) and the inter-individual variation was higher compared to the adult population. The cortices appeared to be markedly less mineralized (CaMean -3.1%, p<0.0001) than cancellous bone due to higher amounts of low mineralized secondary bone. However, the cortical BMDD parameters showed a strong correlation (r=0.38 to 0.85, with p<0.001 to<0.0001) with cancellous BMDD parameters. In conclusion, this study provides evidence that BMDD parameters in growing healthy subjects are relatively constant and that these data can be used as normative references in pediatrics osteology. The larger inter-individual variability compared to adults is most likely related to alterations of the bone turnover rate during growth.
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Affiliation(s)
- N Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK and AUVA Trauma Centre Meidling, 4th Med. Department, Hanusch Hospital, Heinrich Collin Str. 30, 1140 Vienna, Austria.
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40
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Karlic H, Varga F, Noesslinger T, Pittermann E, Klaushofer K, Pfeilstoecker M. P061 Concordant regulation of estrogen receptor, fat metabolism and osteocalcin in myelodysplastic syndromes. Leuk Res 2009. [DOI: 10.1016/s0145-2126(09)70141-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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41
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Blouin S, Thaler HW, Korninger C, Schmid R, Hofstaetter JG, Zoehrer R, Phipps R, Klaushofer K, Roschger P, Paschalis EP. Bone matrix quality and plasma homocysteine levels. Bone 2009; 44:959-64. [PMID: 19168164 DOI: 10.1016/j.bone.2008.12.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 12/15/2008] [Accepted: 12/26/2008] [Indexed: 10/21/2022]
Abstract
It has recently been reported in the clinical literature that blood homocysteine levels correlate well with fracture risk, although a couple of reports exist to the opposite. Bone strength depends on both bone quantity and quality. The purpose of the present study was to investigate possible correlations between plasma homocysteine levels and bone material properties (Bone Mineral Density Distribution; BMDD, and collagen cross-link ratio). In the present study, femoral heads from subjects (N=19, females, age range 70-95 years old) with known homocysteine plasma levels were investigated. The bone material was collected during hemiarthroplasty surgery. We have determined collagen cross-link ratio and bone mineralization density distribution (BMDD) in bone tissue from patients with acute femoral neck fractures, by Fourier Transform Infrared Imaging (FTIRI) and quantitative Backscattered Electron Imaging (qBEI), respectively. The collagen cross-link ratio that was spectroscopically determined was pyridinoline/divalent cross-links (pyr/divalent). The BMDD variables quantified were: CaMean: the weighted mean calcium concentration; CaPeak: the most frequent Ca concentration; CaWidth: the width of the distribution, a measure of the mineralization homogeneity; CaLow: the percentage of bone area that is mineralized below the 5th percentile in the reference range; CaHigh: the percentage of bone area that is mineralized above the 95th percentile in the reference range. There was a significant correlation between plasma homocysteine levels and collagen cross-link ratio in areas of primary mineralized bone (p<0.0001), unlike the case of trabecular bone surfaces undergoing resorption (p>0.05). On the other hand there was no correlation in any of the BMDD parameters and plasma homocysteine levels (p>0.05). The results are consistent with the known effect of homocysteine on collagen post-translational modifications. These changes were independent of bone mineral characteristics. The results of the present study offer a mechanism by which homocysteine affects bone quality, but caution should be exercised since all patients examined had sustained fracture.
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Affiliation(s)
- S Blouin
- 4th Medical Department, Ludwig Boltzmann Institute of Osteology, Hanusch Hospital of WGKK, AUVA Trauma Centre Meidling, Hanusch Hospital, Austria
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42
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Nawrot-Wawrzyniak K, Varga F, Nader A, Roschger P, Sieghart S, Zwettler E, Roetzer KM, Lang S, Weinkamer R, Klaushofer K, Fratzl-Zelman N. Effects of tumor-induced osteomalacia on the bone mineralization process. Calcif Tissue Int 2009; 84:313-23. [PMID: 19219382 DOI: 10.1007/s00223-009-9216-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Accepted: 01/04/2009] [Indexed: 11/28/2022]
Abstract
Fibroblast growth factor 23 (FGF23) overexpression has been identified as a causative factor for tumor-induced osteomalacia (TIO) characterized by hypophosphatemia due to increased renal phosphate wasting, low 1,25(OH)(2)D(3) serum levels, and low bone density. The effects of long-lasting disturbed phosphate homeostasis on bone mineralization are still not well understood. We report on a patient with a 12-year history of TIO, treated with 1,25(OH)(2)D(3) and phosphate, who finally developed hyperparathyroidism with gland hyperplasia before the tumor could be localized in the scapula and removed. During surgery a transiliac bone biopsy was obtained. FGF23 expression in the tumor cells was confirmed by in situ hybridization. Serum FGF23 levels as measured by ELISA were found to be extremely elevated before and decreased after removal of the tumor. Bone histology/histomorphometry and measurement of bone mineralization density distribution using quantitative backscattered electron imaging were performed on the bone biopsy. The data showed important surface osteoidosis and a slightly increased osteoblast but markedly decreased osteoclast number. The mineralized bone volume (-11%) and mineralized trabecular thickness (-18%) were low. The mean degree of mineralization of the bone matrix (-7%), the most frequent calcium concentration (-4.1%), and the amounts of fully mineralized bone (-40.3%) were distinctly decreased, while the heterogeneity of mineralization (+44.5%) and the areas of primary mineralization (+131.6%) were dramatically increased. We suggest that the elevated levels of FGF23 and/or low phosphate concentrations disturb the mineralization kinetics in vivo without affecting matrix mineralization of pre-existing bone packets.
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Affiliation(s)
- K Nawrot-Wawrzyniak
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK, 1140, Vienna, Austria
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43
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Skoumal M, Haberhauer G, Fink A, Steiner A, Klingler A, Varga F, Klaushofer K. Increased serum levels of cartilage oligomeric matrix protein in patients with psoriasis vulgaris: a marker for unknown peripheral joint involvement? Clin Exp Rheumatol 2008; 26:1087-1090. [PMID: 19210875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVE Cartilage oligomeric matrix protein (COMP) is a parameter for the current extent of cartilage destruction. It has been shown that the release pattern of cartilage oligomeric matrix protein in serum reflects cartilage turnover. The aim of our study was to explore the utility of sCOMP as a marker for disease activity in patients with active psoriatic arthritis (PsA) in comparison to a control group only with psoriasis vulgaris (PV). METHODS Serum levels of COMP were measured in 64 patients with PsA and psoriasis vulgaris. The control group consisted of a population with PV from a dermatological outpatient clinic. ELISA-tests were used to detect sCOMP levels according to the manufacturer instructions. RESULTS In our 64 patients with PsA, we found increased sCOMP levels, which correlated significantly with inflammatory parameters and the number of swollen joints. Patients with active PsA had significantly higher sCOMP levels (p<0.0001) than the 39 patients with a low inflammatory status. In our control group with PV we also found elevated sCOMP levels, which correlated significantly with the increased C-reactive protein (CRP) levels in this group. The difference between the PsA and the PV group was not significant (p=0.092). CONCLUSION In our study, sCOMP has been demonstrated to be an indicator for disease activity in patients with PsA. Patients with active PsA showed significantly elevated sCOMP levels compared to the patients with low clinical and laboratory disease activity. The increased sCOMP levels in our control group with PV indicate that all patients with psoriatic lesions should be screened for additional joint involvement and should lead to an exact joint examination.
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Affiliation(s)
- M Skoumal
- Institute for Rheumatology of the Kurstadt Baden in Cooperation with the Danube, University Krems, Baden, Austria
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44
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Cejka D, Benesch T, Krestan C, Roschger P, Klaushofer K, Pietschmann P, Haas M. Effect of teriparatide on early bone loss after kidney transplantation. Am J Transplant 2008; 8:1864-70. [PMID: 18786230 DOI: 10.1111/j.1600-6143.2008.02327.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Kidney transplantation is associated with bone loss and a high risk of fractures. Prophylactic treatment of bone is therefore recommended in the early posttransplant period. As a large number of transplant recipients develop adynamic renal osteodystrophy, recombinant parathyroid hormone (rPTH) could be a promising therapeutic option. In a 6-month double-blind, randomized trial, 26 kidney transplant recipients were treated with daily subcutaneous injections of 20 microg teriparatide (PTH 1-34) or placebo. Bone mineral density (BMD) of the femoral neck, lumbar spine and radial bone was measured at transplantation and after 6 months. Paired bone biopsies for histomorphometric analysis were obtained in six, and for measurement of bone matrix mineralization in five patients of each group. Serologic bone markers were measured at baseline and every 3 months. A total of 24 out of 26 patients completed the study. Femoral neck BMD was stable in the teriparatide group, but decreased significantly in the placebo group. Lumbar spine and radial BMD, histomorphometric bone volume and bone matrix mineralization status remained unchanged in both groups. Serologic bone markers were similarly reduced in both groups throughout the study. We conclude that teriparatide does not improve BMD early after kidney transplantation. Neither histological analysis nor bone markers provide evidence of improved bone turnover or mineralization.
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Affiliation(s)
- D Cejka
- Department of Internal Medicine III, Division of Nephrology and Dialysis, Medical University Vienna, Vienna, Austria
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45
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Misof BM, Bodingbauer M, Roschger P, Wekerle T, Pakrah B, Haas M, Kainz A, Oberbauer R, Mühlbacher F, Klaushofer K. Short-term effects of high-dose zoledronic acid treatment on bone mineralization density distribution after orthotopic liver transplantation. Calcif Tissue Int 2008; 83:167-75. [PMID: 18712431 DOI: 10.1007/s00223-008-9161-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Accepted: 07/02/2008] [Indexed: 10/21/2022]
Abstract
Patients with "hepatic" bone disease exhibit increased fracture incidence. The effects on bone material properties, their changes due to orthotopic liver transplantation (OLT), as well as zolendronate (ZOL) treatment have not yet been investigated. We studied bone mineralization density distribution (BMDD) in paired transiliacal biopsies (at and 6 months after OLT) from patients (control CON n = 18, treatment group ZOL n = 21, the latter treated with i.v. ZOL at doses of 4 mg/month) for how bone at the material level was affected by the "hepatic" disease in general, as well as by OLT and ZOL in particular. (1) BMDD parameters at baseline reflected disturbed bone matrix mineralization in "hepatic" bone disease combined with low turnover. Trabecular bone displayed a decrease in mean and most frequent calcium concentration (Ca(MEAN) -2.9% and Ca(PEAK) -2.8%, respectively; both P < 0.001), increased heterogeneity of mineralization (Ca(WIDTH) +12.2%, P = 0.01), and increased percentage of bone areas with low mineralization (Ca(LOW) +32.4%, P = 0.02) compared to normal; however, there were no differences compared to cortical bone. (2) Six months after OLT, ZOL-treated trabecular bone displayed reduced Ca(LOW) (-32.0%, P = 0.047), cortical bone increased Ca(MEAN) (+4.2%, P = 0.009), increased Ca(PEAK) (+3.3%, P = 0.040), and decreased Ca(LOW) (-55.7, P = 0.038) compared to CON and increased Ca(MEAN) compared to baseline (+1.9, P = 0.032) without any signs of hyper- or defective mineralization. These changes as consequence of the antiresorptive action of ZOL visible already after 6 months result in beneficial effects on bone matrix mineralization, likely contributing to the significant decrease in fracture incidence observed in these patients 2 years post transplantation.
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Affiliation(s)
- B M Misof
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department at Hanusch Hospital, UKH Meidling, Kundratstr. 37, 1120 Vienna, Austria.
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46
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Turecek C, Fratzl-Zelman N, Rumpler M, Buchinger B, Spitzer S, Zoehrer R, Durchschlag E, Klaushofer K, Paschalis EP, Varga F. Collagen cross-linking influences osteoblastic differentiation. Calcif Tissue Int 2008; 82:392-400. [PMID: 18488133 DOI: 10.1007/s00223-008-9136-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Accepted: 04/06/2008] [Indexed: 01/22/2023]
Abstract
Osteoblasts synthesize collagen matrix, which itself regulates the differentiation of precursor cells into mature osteoblasts. They express lysyl oxidase (LOX), which is involved in the collagen cross-linking process. Lathyrogens, like ss-aminopropionitrile (ssAPN), inhibit the formation of a stable matrix. The aim of the present study was to investigate the influence of cross-linking on osteoblastic differentiation. MC3T3-E1 cells were seeded and treated with or without 400 muM ssAPN for 1 week. Thereafter, living cells were removed and, on this extracellular matrix, new MC3T3-E1 cells were seeded and cultured for 1 week without ssAPN. RNA was isolated, and expression of specific marker genes was determined by quantitative reverse transcription-polymerase chain reaction. Changes in specific cross-links after ssAPN treatment were measured with Fourier-transform infrared spectroscopy. The collagen matrix that formed showed a significant reduction of two major cross-links of bone collagen, deH-DHLNL and pyr, compared to control cultures. Gene expression studies showed an increase of collagen alpha1 (I) (COL1A1) to 150%. Expression of LOX and osteocalcin (OCN) mRNA was significantly downregulated to about 75%. When fresh MC3T3-E1 cells were seeded on this altered matrix without ssAPN, COL1A1 mRNA expression was upregulated (140%), OCN was downregulated (60%), and LOX mRNA expression remained unaffected. These results indicate that ssAPN treatment not only disrupts collagen cross-link formation but also affects osteoblastic activity and expression. In conclusion, the disrupted matrix produced in the presence of lathyrogen influences, even in its absence, the expression of osteoblastic genes.
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Affiliation(s)
- C Turecek
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of WGKK and AUVA Trauma Center Meidling, 4th Medical Department, Hanusch Hospital, Heinrich Collinstrasse 30, Vienna, Austria
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47
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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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48
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Bodingbauer M, Wekerle T, Pakrah B, Roschger P, Peck-Radosavljevic M, Silberhumer G, Grampp S, Rockenschaub S, Berlakovich G, Steininger R, Klaushofer K, Oberbauer R, Mühlbacher F. Prophylactic bisphosphonate treatment prevents bone fractures after liver transplantation. Am J Transplant 2007; 7:1763-9. [PMID: 17511759 DOI: 10.1111/j.1600-6143.2007.01844.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A randomized controlled prospective open-label single center trial was performed. At the time of transplantation patients were randomly assigned to one of two treatment arms: The study group of 47 patients received zoledronic acid (ZOL, 8 infusions at 4 mg during the first 12 months after LT), calcium (1000 mg/d) and vitamin D (800 IE/d). The control group consisted of 49 patients who received calcium and vitamin D at same doses (CON). The incidence of bone fractures or death was predefined as the primary endpoint. Secondary endpoints included bone mineral density (BMD), serum biochemical markers of bone metabolism, parameters of trabecular bone histomorphometry and mineralization density distribution (BMDD). Patients were followed up for 24 months. Analysis was performed on an intention-to-treat basis. The primary endpoint fracture or death was reached in 26% of patients in the ZOL group and 46% in the CON group (p = 0.047, log rank test). Densitometry results were different between the groups at the femoral neck at 6 months after LT (mean+/-SD BMD ZOL: 0.80 +/- 0.19 g/cm2 vs. CON: 0.73 +/- 0.14 g/cm2, p = 0.036). Mixed linear models of biochemical bone markers showed less increase of osteocalcin in the ZOL group and histomorphometry and BMDD indicated a reduction in bone turnover. Prophylactic treatment with the bisphosphonate zoledronic acid reduces bone turnover and fractures after liver transplantation.
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Affiliation(s)
- M Bodingbauer
- Division of Transplantation, Department of Surgery, Medical University of Vienna, Vienna, Austria.
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49
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Ruffoni D, Fratzl P, Roschger P, Klaushofer K, Weinkamer R. The bone mineralization density distribution as a fingerprint of the mineralization process. Bone 2007; 40:1308-19. [PMID: 17337263 DOI: 10.1016/j.bone.2007.01.012] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 12/22/2006] [Accepted: 01/19/2007] [Indexed: 11/19/2022]
Abstract
The inhomogeneous mineral content and its topographical distribution on a microscopic scale are major determinants of the mechanical quality of trabecular bone. The kinetics of bone tissue deposition and resorption together with the kinetics of the mineralization process determine the distribution of mineral in the tissue. The heterogeneity of the mineral content is described by the well-established bone mineralization density distribution (BMDD), which is experimentally accessible, e.g., using quantitative electron backscattering imaging (qBEI). In the present work, we demonstrate that the shape of the BMDD histogram of trabecular bone reflects directly the mineralization kinetics. Based on the experimental BMDD data of trabecular bone from healthy human adults and using a mathematical model for the remodeling and the mineralization process, the following main results were obtained. The peaked BMDD reflects necessarily a two-phase mineralization process with a fast primary phase and a slow secondary phase where the corresponding time constants differ three orders of magnitude. The obtained mineralization law, which describes the increase in the mineral content in a bone packet as a function of time, provides information not only about the initial mineralization surge, but also about the slow increase afterwards on the time scale of years. In addition to the mineralization kinetics the turnover rate of the remodeling process has a strong influence on the peak position and the shape of the BMDD. The described theoretical framework opens new possibilities for an analysis of experimentally measured BMDDs with respect to changes caused by diseases or treatments. It allows addressing whether changes in the BMDD have to be attributed to a variation in the turnover rate which consequently affects the density distribution or to a primary disorder in the mineralization process most likely reflecting alterations of the organic matrix. This is of important clinical interest because it helps to find therapeutic approaches directly targeting the primary etiological defects to correct the patients' BMDD towards normal BMDD.
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Affiliation(s)
- D Ruffoni
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, 14424 Potsdam, Germany
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50
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Rumpler M, Woesz A, Varga F, Manjubala I, Klaushofer K, Fratzl P. Three-dimensional growth behavior of osteoblasts on biomimetic hydroxylapatite scaffolds. J Biomed Mater Res A 2007; 81:40-50. [PMID: 17109410 DOI: 10.1002/jbm.a.30940] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The authors used rapid prototyping to produce three-dimensional hydroxylapatite scaffolds with controlled, fully interconnected porosity. The purpose of this study was to illuminate the effect of hormones on the osteogenic differentiation and to investigate how osteoblasts colonize the three-dimensional scaffold focusing on the formation of the cellular network. Preosteoblasts were seeded onto scaffolds, were optionally treated with the osteogenic hormones triiodo-L-thyronine (T3) and 1,25-dihydroxyvitamin-D3 (D3), and the expression of osteoblastic marker genes was investigated. Confocal laser scanning microscopy was used to investigate the three-dimensional growth behavior. Culturing cells on scaffolds strongly increased the expression of osteocalcin, osteoprotegerin, Runx2, and receptor activator of NFkB-ligand (RANKL). Treatment with T3 increased the expression of osteocalcin but did not change that of osteoprotegerin and Runx2. Treatment with D3 inhibited the expression of osteocalcin, Runx2, and osteoprotegerin. Both hormones had similar effects in the three-dimensional system as found in two-dimensional cultures although more accentuated, indicating that preosteoblasts behave more naturally on three-dimensional structures. The osteoblasts colonized the three-dimensional squared pores of scaffolds by forming a cellular network with a round central channel keeping it into the depth and depositing collagen fibrils. These results provide insight how osteoblasts colonize a three-dimensional system and underline the importance of this environment in osteoblastic differentiation studies.
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Affiliation(s)
- M Rumpler
- Department of Biomaterials, Max Planck Institute for Colloids and Interfaces, 14424 Potsdam, Germany.
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