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Vom Scheidt A, Krug J, Goggin P, Bakker AD, Busse B. 2D vs. 3D Evaluation of Osteocyte Lacunae - Methodological Approaches, Recommended Parameters, and Challenges: A Narrative Review by the European Calcified Tissue Society (ECTS). Curr Osteoporos Rep 2024; 22:396-415. [PMID: 38980532 DOI: 10.1007/s11914-024-00877-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/11/2024] [Indexed: 07/10/2024]
Abstract
PURPOSE OF REVIEW Quantification of the morphology of osteocyte lacunae has become a powerful tool to investigate bone metabolism, pathologies and aging. This review will provide a brief overview of 2D and 3D imaging methods for the determination of lacunar shape, orientation, density, and volume. Deviations between 2D-based and 3D-based lacunar volume estimations are often not sufficiently addressed and may give rise to contradictory findings. Thus, the systematic error arising from 2D-based estimations of lacunar volume will be discussed, and an alternative calculation proposed. Further, standardized morphological parameters and best practices for sampling and segmentation are suggested. RECENT FINDINGS We quantified the errors in reported estimation methods of lacunar volume based on 2D cross-sections, which increase with variations in lacunar orientation and histological cutting plane. The estimations of lacunar volume based on common practice in 2D imaging methods resulted in an underestimation of lacunar volume of up to 85% compared to actual lacunar volume in an artificial dataset. For a representative estimation of lacunar size and morphology based on 2D images, at least 400 lacunae should be assessed per sample.
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Affiliation(s)
- Annika Vom Scheidt
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Auenbruggerplatz 25, Graz, 8036, Austria.
| | - Johannes Krug
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 55a, 22529, Hamburg, Germany
- Interdisciplinary Competence Center for Interface Research, University Medical Center Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany
| | - Patricia Goggin
- Biomedical Imaging Unit, Laboratory and Pathology Block, University of Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, UK
| | - Astrid Diana Bakker
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam Movement Sciences, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan, Amsterdam, 3004, 1081 LA, The Netherlands
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestr. 55a, 22529, Hamburg, Germany
- Interdisciplinary Competence Center for Interface Research, University Medical Center Hamburg-Eppendorf, Butenfeld 34, 22529, Hamburg, Germany
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Yu B, Gauthier R, Olivier C, Villanova J, Follet H, Mitton D, Peyrin F. 3D quantification of the lacunocanalicular network on human femoral diaphysis through synchrotron radiation-based nanoCT. J Struct Biol 2024; 216:108111. [PMID: 39059753 DOI: 10.1016/j.jsb.2024.108111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 07/09/2024] [Accepted: 07/22/2024] [Indexed: 07/28/2024]
Abstract
Osteocytes are the major actors in bone mechanobiology. Within bone matrix, they are trapped close together in a submicrometric interconnected network: the lacunocanalicular network (LCN). The interstitial fluid circulating within the LCN transmits the mechanical information to the osteocytes that convert it into a biochemical signal. Understanding the interstitial fluid dynamics is necessary to better understand the bone mechanobiology. Due to the submicrometric dimensions of the LCN, making it difficult to experimentally investigate fluid dynamics, numerical models appear as a relevant tool for such investigation. To develop such models, there is a need for geometrical and morphological data on the human LCN. This study aims at providing morphological data on the human LCN from measurement of 27 human femoral diaphysis bone samples using synchrotron radiation nano-computed tomography with an isotropic voxel size of 100 nm. Except from the canalicular diameter, the canalicular morphological parameters presented a high variability within one sample. Some differences in terms of both lacunar and canalicular morphology were observed between the male and female populations. But it has to be highlighted that all the canaliculi cannot be detected with a voxel size of 100 nm. Hence, in the current study, only a specific population of large canaliculi that could be characterize. Still, to the authors knowledge, this is the first time such a data set was introduced to the community. Further processing will be achieved in order to provide new insight on the LCN permeability.
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Affiliation(s)
- Boliang Yu
- Univ Lyon, INSA Lyon, Universite Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS UMR 5220, Inserm U1206, CREATIS, 69621 Lyon, France
| | - Remy Gauthier
- CNRS, INSA Lyon, Universite Claude Bernard Lyon 1 UCBL, MATEIS UMR CNRS 5510, Bât. Saint Exupéry, 23 Av. Jean Capelle, F-69621 Villeurbanne, France.
| | - Cécile Olivier
- Université Grenoble Alpes, Institut National de la Santé et de la Recherche Médicale, UA7 Synchrotron Radiation for Biomedicine, Saint-Martin d'Hères, France
| | | | - Hélène Follet
- Univ Lyon, Universite Claude Bernard Lyon 1, INSERM, LYOS UMR1033, Lyon, France
| | - David Mitton
- Univ Lyon, Univ Gustave Eiffel, Universite Claude Bernard Lyon 1, LBMC UMR_T9406, 69622 Lyon, France
| | - Francoise Peyrin
- Univ Lyon, INSA Lyon, Universite Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS UMR 5220, Inserm U1206, CREATIS, 69621 Lyon, France
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Chen J, Aido M, Roschger A, van Tol A, Checa S, Willie BM, Weinkamer R. Spatial variations in the osteocyte lacuno-canalicular network density and analysis of the connectomic parameters. PLoS One 2024; 19:e0303515. [PMID: 38743675 PMCID: PMC11093372 DOI: 10.1371/journal.pone.0303515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 04/05/2024] [Indexed: 05/16/2024] Open
Abstract
Osteocyte lacuno-canalicular network (LCN) is comprised of micrometre-sized pores and submicrometric wide channels in bone. Accumulating evidence suggests multiple functions of this network in material transportation, mechanobiological signalling, mineral homeostasis and bone remodelling. Combining rhodamine staining and confocal laser scanning microscopy, the longitudinal cross-sections of six mouse tibiae were imaged, and the connectome of the network was quantified with a focus on the spatial heterogeneities of network density, connectivity and length of canaliculi. In-vivo loading and double calcein labelling on these tibiae allowed differentiating the newly formed bone from the pre-existing regions. The canalicular density of the murine cortical bone varied between 0.174 and 0.243 μm/μm3, and therefore is three times larger than the corresponding value for human femoral midshaft osteons. The spatial heterogeneity of the network was found distinctly more pronounced across the cortex than along the cortex. We found that in regions with a dense network, the LCN conserves its largely tree-like character, but increases the density by including shorter canaliculi. The current study on healthy mice should serve as a motivating starting point to study the connectome of genetically modified mice, including models of bone diseases and of reduced mechanoresponse.
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Affiliation(s)
- Junning Chen
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Department of Engineering, Faculty of Environment, Science and Economy, University of Exeter, Exeter, United Kingdom
| | - Marta Aido
- Julius Wolff Institute, Charité-Universitätsmedizin Berlin, Berlin, Germany
- Berlin-Brandenburg School for Regenerative Therapies (BSRT), Berlin, Germany
| | - Andreas Roschger
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Department of Chemistry and Physics of Materials, Paris-Lodron-University of Salzburg, Salzburg, Austria
| | - Alexander van Tol
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Sara Checa
- Julius Wolff Institute, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Bettina M. Willie
- Department of Pediatric Surgery, Research Centre, Shriners Hospital for Children-Canada, McGill University, Montreal, Canada
| | - Richard Weinkamer
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
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Silveira A, Greving I, Longo E, Scheel M, Weitkamp T, Fleck C, Shahar R, Zaslansky P. Deep learning to overcome Zernike phase-contrast nanoCT artifacts for automated micro-nano porosity segmentation in bone. JOURNAL OF SYNCHROTRON RADIATION 2024; 31:136-149. [PMID: 38095668 PMCID: PMC10833422 DOI: 10.1107/s1600577523009852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 11/13/2023] [Indexed: 01/09/2024]
Abstract
Bone material contains a hierarchical network of micro- and nano-cavities and channels, known as the lacuna-canalicular network (LCN), that is thought to play an important role in mechanobiology and turnover. The LCN comprises micrometer-sized lacunae, voids that house osteocytes, and submicrometer-sized canaliculi that connect bone cells. Characterization of this network in three dimensions is crucial for many bone studies. To quantify X-ray Zernike phase-contrast nanotomography data, deep learning is used to isolate and assess porosity in artifact-laden tomographies of zebrafish bones. A technical solution is proposed to overcome the halo and shade-off domains in order to reliably obtain the distribution and morphology of the LCN in the tomographic data. Convolutional neural network (CNN) models are utilized with increasing numbers of images, repeatedly validated by `error loss' and `accuracy' metrics. U-Net and Sensor3D CNN models were trained on data obtained from two different synchrotron Zernike phase-contrast transmission X-ray microscopes, the ANATOMIX beamline at SOLEIL (Paris, France) and the P05 beamline at PETRA III (Hamburg, Germany). The Sensor3D CNN model with a smaller batch size of 32 and a training data size of 70 images showed the best performance (accuracy 0.983 and error loss 0.032). The analysis procedures, validated by comparison with human-identified ground-truth images, correctly identified the voids within the bone matrix. This proposed approach may have further application to classify structures in volumetric images that contain non-linear artifacts that degrade image quality and hinder feature identification.
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Affiliation(s)
- Andreia Silveira
- Department for Restorative, Preventive and Pediatric Dentistry, Charité-Universitaetsmedizin, Berlin, Germany
| | - Imke Greving
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
| | - Elena Longo
- Elettra – Sincrotrone Trieste SCpA, Basovizza, Trieste, Italy
| | | | | | - Claudia Fleck
- Fachgebiet Werkstofftechnik / Chair of Materials Science and Engineering, Institute of Materials Science and Technology, Faculty III Process Sciences, Technische Universität Berlin, Berlin, Germany
| | - Ron Shahar
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environmental Sciences, Hebrew University of Jerusalem, Rehovot, Israel
| | - Paul Zaslansky
- Department for Restorative, Preventive and Pediatric Dentistry, Charité-Universitaetsmedizin, Berlin, Germany
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Sefa S, Espiritu J, Ćwieka H, Greving I, Flenner S, Will O, Beuer S, Wieland DF, Willumeit-Römer R, Zeller-Plumhoff B. Multiscale morphological analysis of bone microarchitecture around Mg-10Gd implants. Bioact Mater 2023; 30:154-168. [PMID: 37575877 PMCID: PMC10412723 DOI: 10.1016/j.bioactmat.2023.07.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 07/07/2023] [Accepted: 07/20/2023] [Indexed: 08/15/2023] Open
Abstract
The utilization of biodegradable magnesium (Mg)-based implants for restoration of bone function following trauma represents a transformative approach in orthopaedic application. One such alloy, magnesium-10 weight percent gadolinium (Mg-10Gd), has been specifically developed to address the rapid degradation of Mg while enhancing its mechanical properties to promote bone healing. Previous studies have demonstrated that Mg-10Gd exhibits favorable osseointegration; however, it exhibits distinct ultrastructural adaptation in comparison to conventional implants like titanium (Ti). A crucial aspect that remains unexplored is the impact of Mg-10Gd degradation on the bone microarchitecture. To address this, we employed hierarchical three-dimensional imaging using synchrotron radiation in conjunction with image-based finite element modelling. By using the methods outlined, the vascular porosity, lacunar porosity and the lacunar-canaliculi network (LCN) morphology of bone around Mg-10Gd in comparison to Ti in a rat model from 4 weeks to 20 weeks post-implantation was investigated. Our investigation revealed that within our observation period, the degradation of Mg-10Gd implants was associated with significantly lower (p < 0.05) lacunar density in the surrounding bone, compared to Ti. Remarkably, the LCN morphology and the fluid flow analysis did not significantly differ for both implant types. In summary, a more pronounced lower lacunae distribution rather than their morphological changes was detected in the surrounding bone upon the degradation of Mg-10Gd implants. This implies potential disparities in bone remodelling rates when compared to Ti implants. Our findings shed light on the intricate relationship between Mg-10Gd degradation and bone microarchitecture, contributing to a deeper understanding of the implications for successful osseointegration.
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Affiliation(s)
- Sandra Sefa
- Institute of Metallic Biomaterials, Helmholtz Zentrum Hereon, Geesthacht, Germany
| | | | - Hanna Ćwieka
- Institute of Metallic Biomaterials, Helmholtz Zentrum Hereon, Geesthacht, Germany
| | - Imke Greving
- Institute of Materials Physics, Helmholtz Zentrum Hereon, Geesthacht, Germany
| | - Silja Flenner
- Institute of Materials Physics, Helmholtz Zentrum Hereon, Geesthacht, Germany
| | - Olga Will
- Molecular Imaging North Competence Center, Kiel University, Kiel, Germany
| | - Susanne Beuer
- Fraunhofer Institut für Integrierte Systeme und Bauelementetechnologie (IISB), Erlangen, Germany
| | - D.C Florian Wieland
- Institute of Metallic Biomaterials, Helmholtz Zentrum Hereon, Geesthacht, Germany
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Østergaard M, Naver EB, Schüpbach D, Kaestner A, Strobl M, Brüel A, Thomsen JS, Schmidt S, Poulsen HF, Kuhn LT, Birkedal H. Correlative study of liquid in human bone by 3D neutron microscopy and lab-based X-ray μCT. Bone 2023; 175:116837. [PMID: 37419297 DOI: 10.1016/j.bone.2023.116837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 06/30/2023] [Accepted: 07/04/2023] [Indexed: 07/09/2023]
Abstract
Liquid plays an important role in bone that has a complex 3D hierarchical pore structure. However, liquid (water) is difficult to discern from e.g. an organic matrix by X-ray imaging. Therefore, we use a correlative approach using both high resolution X-ray and neutron imaging. Human femoral bone with liquid adsorbed into some of the pores was imaged with both the Neutron Microscope at the ICON beamline, SINQ at PSI, and by lab-based μCT using 2.7 μm voxel size. Segmentation of the two datasets showed that, even though the liquid was clearly distinguishable in the neutron data and not in the X-ray data, it remained challenging to segment it from bone due to overlaps of peaks in the gray level histograms. In consequence, segmentations from X-ray and neutron data varied significantly. To address this issue, the segmented X-ray porosities was overlaid on the neutron data, making it possible to localize the liquid in the vascular porosities of the bone sample and use the neutron attenuation to identify it as H2O. The contrast in the neutron images was lowered slightly between the bone and the liquid compared to the bone and the air. This correlative study shows that the complementary use of X-rays and neutrons is very favorable, since H2O is very distinct in the neutron data, while D2O, H2O, and organic matter can barely be distinguished from air in the X-ray data.
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Affiliation(s)
- Maja Østergaard
- Department of Chemistry and iNANO, Aarhus University, Aarhus, Denmark.
| | - Estrid Buhl Naver
- Department of Energy Conversion and Storage, Technical University of Denmark, Kongens Lyngby, Denmark.
| | - Delia Schüpbach
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen, Switzerland.
| | - Anders Kaestner
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen, Switzerland.
| | - Markus Strobl
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen, Switzerland; Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
| | - Annemarie Brüel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.
| | | | - Søren Schmidt
- Data Management and Software Centre, European Spallation Source, Lund, Sweden.
| | | | - Luise Theil Kuhn
- Department of Energy Conversion and Storage, Technical University of Denmark, Kongens Lyngby, Denmark.
| | - Henrik Birkedal
- Department of Chemistry and iNANO, Aarhus University, Aarhus, Denmark.
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He T, Pang Z, Yin Y, Xue H, Pang Y, Song H, Li J, Bai R, Qin A, Kong X. Micron-resolution Imaging of Cortical Bone under 14 T Ultrahigh Magnetic Field. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300959. [PMID: 37339792 PMCID: PMC10460861 DOI: 10.1002/advs.202300959] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 05/11/2023] [Indexed: 06/22/2023]
Abstract
Compact, mineralized cortical bone tissues are often concealed on magnetic resonance (MR) images. Recent development of MR instruments and pulse techniques has yielded significant advances in acquiring anatomical and physiological information from cortical bone despite its poor 1 H signals. This work demonstrates the first MR research on cortical bones under an ultrahigh magnetic field of 14 T. The 1 H signals of different mammalian species exhibit multi-exponential decays of three characteristic T2 or T2 * values: 0.1-0.5 ms, 1-4 ms, and 4-8 ms. Systematic sample comparisons attribute these T2 /T2 * value ranges to collagen-bound water, pore water, and lipids, respectively. Ultrashort echo time (UTE) imaging under 14 T yielded spatial resolutions of 20-80 microns, which resolves the 3D anatomy of the Haversian canals. The T2 * relaxation characteristics further allow spatial classifications of collagen, pore water and lipids in human specimens. The study achieves a record of the spatial resolution for MR imaging in bone and shows that ultrahigh-field MR has the unique ability to differentiate the soft and organic compartments in bone tissues.
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Affiliation(s)
- Tian He
- Department of ChemistryZhejiang UniversityHangzhou310027China
| | - Zhenfeng Pang
- Department of ChemistryZhejiang UniversityHangzhou310027China
| | - Yu Yin
- Department of ChemistryZhejiang UniversityHangzhou310027China
| | - Huadong Xue
- Department of ChemistryZhejiang UniversityHangzhou310027China
- Department of RehabilitationSir Run Run Shaw HospitalCollege of MedicineZhejiang UniversityHangzhou310016China
| | - Yichuan Pang
- Shanghai Key Laboratory of Orthopedic ImplantsDepartment of OrthopaedicsShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghai200011China
| | - Haixin Song
- Department of RehabilitationSir Run Run Shaw HospitalCollege of MedicineZhejiang UniversityHangzhou310016China
| | - Jianhua Li
- Department of RehabilitationSir Run Run Shaw HospitalCollege of MedicineZhejiang UniversityHangzhou310016China
| | - Ruiliang Bai
- Interdisciplinary Institute of Neuroscience and Technology (ZIINT)College of Biomedical Engineering and Instrument ScienceZhejiang UniversityHangzhou310027China
- School of MedicineZhejiang UniversityHangzhou310058China
| | - An Qin
- Shanghai Key Laboratory of Orthopedic ImplantsDepartment of OrthopaedicsShanghai Ninth People's HospitalShanghai Jiao Tong University School of MedicineShanghai200011China
| | - Xueqian Kong
- Department of ChemistryZhejiang UniversityHangzhou310027China
- Department of RehabilitationSir Run Run Shaw HospitalCollege of MedicineZhejiang UniversityHangzhou310016China
- Institute of Translational MedicineShanghai Jiaotong UniversityShanghai200240China
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Detailing the influence of PEO-coated biodegradable Mg-based implants on the lacuno-canalicular network in sheep bone: A pilot study. Bioact Mater 2023; 26:14-23. [PMID: 36875051 PMCID: PMC9975618 DOI: 10.1016/j.bioactmat.2023.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/31/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
An increasing prevalence of bone-related injuries and aging geriatric populations continue to drive the orthopaedic implant market. A hierarchical analysis of bone remodelling after material implantation is necessary to better understand the relationship between implant and bone. Osteocytes, which are housed and communicate through the lacuno-canalicular network (LCN), are integral to bone health and remodelling processes. Therefore, it is essential to examine the framework of the LCN in response to implant materials or surface treatments. Biodegradable materials offer an alternative solution to permanent implants, which may require revision or removal surgeries. Magnesium alloys have resurfaced as promising materials due to their bone-like properties and safe degradation in vivo. To further tailor their degradation capabilities, surface treatments such as plasma electrolytic oxidation (PEO) have demonstrated to slow degradation. For the first time, the influence of a biodegradable material on the LCN is investigated by means of non-destructive 3D imaging. In this pilot study, we hypothesize noticeable variations in the LCN caused by altered chemical stimuli introduced by the PEO-coating. Utilising synchrotron-based transmission X-ray microscopy, we have characterised morphological LCN differences around uncoated and PEO-coated WE43 screws implanted into sheep bone. Bone specimens were explanted after 4, 8, and 12 weeks and regions near the implant surface were prepared for imaging. Findings from this investigation indicate that the slower degradation of PEO-coated WE43 induces healthier lacunar shapes within the LCN. However, the stimuli perceived by the uncoated material with higher degradation rates induces a greater connected LCN better prepared for bone disturbance.
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Besnard C, Marie A, Sasidharan S, Harper RA, Shelton RM, Landini G, Korsunsky AM. Synchrotron X-ray Studies of the Structural and Functional Hierarchies in Mineralised Human Dental Enamel: A State-of-the-Art Review. Dent J (Basel) 2023; 11:98. [PMID: 37185477 PMCID: PMC10137518 DOI: 10.3390/dj11040098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/19/2023] [Accepted: 03/28/2023] [Indexed: 05/17/2023] Open
Abstract
Hard dental tissues possess a complex hierarchical structure that is particularly evident in enamel, the most mineralised substance in the human body. Its complex and interlinked organisation at the Ångstrom (crystal lattice), nano-, micro-, and macro-scales is the result of evolutionary optimisation for mechanical and functional performance: hardness and stiffness, fracture toughness, thermal, and chemical resistance. Understanding the physical-chemical-structural relationships at each scale requires the application of appropriately sensitive and resolving probes. Synchrotron X-ray techniques offer the possibility to progress significantly beyond the capabilities of conventional laboratory instruments, i.e., X-ray diffractometers, and electron and atomic force microscopes. The last few decades have witnessed the accumulation of results obtained from X-ray scattering (diffraction), spectroscopy (including polarisation analysis), and imaging (including ptychography and tomography). The current article presents a multi-disciplinary review of nearly 40 years of discoveries and advancements, primarily pertaining to the study of enamel and its demineralisation (caries), but also linked to the investigations of other mineralised tissues such as dentine, bone, etc. The modelling approaches informed by these observations are also overviewed. The strategic aim of the present review was to identify and evaluate prospective avenues for analysing dental tissues and developing treatments and prophylaxis for improved dental health.
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Affiliation(s)
- Cyril Besnard
- MBLEM, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, Oxfordshire, UK
| | - Ali Marie
- MBLEM, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, Oxfordshire, UK
| | - Sisini Sasidharan
- MBLEM, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, Oxfordshire, UK
| | - Robert A. Harper
- School of Dentistry, University of Birmingham, 5 Mill Pool Way, Edgbaston, Birmingham B5 7EG, West Midlands, UK
| | - Richard M. Shelton
- School of Dentistry, University of Birmingham, 5 Mill Pool Way, Edgbaston, Birmingham B5 7EG, West Midlands, UK
| | - Gabriel Landini
- School of Dentistry, University of Birmingham, 5 Mill Pool Way, Edgbaston, Birmingham B5 7EG, West Midlands, UK
| | - Alexander M. Korsunsky
- MBLEM, Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, Oxfordshire, UK
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10
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Insights into the Molecular and Hormonal Regulation of Complications of X-Linked Hypophosphatemia. ENDOCRINES 2023. [DOI: 10.3390/endocrines4010014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
X-linked hypophosphatemia (XLH) is characterized by mutations in the PHEX gene, leading to elevated serum levels of FGF23, decreased production of 1,25 dihydroxyvitamin D3 (1,25D), and hypophosphatemia. Those affected with XLH manifest impaired growth and skeletal and dentoalveolar mineralization as well as increased mineralization of the tendon–bone attachment site (enthesopathy), all of which lead to decreased quality of life. Many molecular and murine studies have detailed the role of mineral ions and hormones in regulating complications of XLH, including how they modulate growth and growth plate maturation, bone mineralization and structure, osteocyte-mediated mineral matrix resorption and canalicular organization, and enthesopathy development. While these studies have provided insight into the molecular underpinnings of these skeletal processes, current therapies available for XLH do not fully prevent or treat these complications. Therefore, further investigations are needed to determine the molecular pathophysiology underlying the complications of XLH.
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11
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Tang T, Landis W, Blouin S, Bertinetti L, Hartmann MA, Berzlanovich A, Weinkamer R, Wagermaier W, Fratzl P. Subcanalicular Nanochannel Volume Is Inversely Correlated With Calcium Content in Human Cortical Bone. J Bone Miner Res 2023; 38:313-325. [PMID: 36433915 DOI: 10.1002/jbmr.4753] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/10/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022]
Abstract
The spatial distribution of mineralization density is an important signature of bone growth and remodeling processes, and its alterations are often related to disease. The extracellular matrix of some vertebrate mineralized tissues is known to be perfused by a lacunocanalicular network (LCN), a fluid-filled unmineralized structure that harbors osteocytes and their fine processes and transports extracellular fluid and its constituents. The current report provides evidence for structural and compositional heterogeneity at an even smaller, subcanalicular scale. The work reveals an extensive unmineralized three-dimensional (3D) network of nanochannels (~30 nm in diameter) penetrating the mineralized extracellular matrix of human femoral cortical bone and encompassing a greater volume fraction and surface area than these same parameters of the canaliculi comprising the LCN. The present study combines high-resolution focused ion beam-scanning electron microscopy (FIB-SEM) to investigate bone ultrastructure in 3D with quantitative backscattered electron imaging (qBEI) to estimate local bone mineral content. The presence of nanochannels has been found to impact qBEI measurements fundamentally, such that volume percentage (vol%) of nanochannels correlates inversely with weight percentage (wt%) of calcium. This mathematical relationship between nanochannel vol% and calcium wt% suggests that the nanochannels could potentially provide space for ion and small molecule transport throughout the bone matrix. Collectively, these data propose a reinterpretation of qBEI measurements, accounting for nanochannel presence in human bone tissue in addition to collagen and mineral. Further, the results yield insight into bone mineralization processes at the nanometer scale and present the possibility for a potential role of the nanochannel system in permitting ion and small molecule diffusion throughout the extracellular matrix. Such a possible function could thereby lead to the sequestration or occlusion of the ions and small molecules within the extracellular matrix. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Tengteng Tang
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - William Landis
- Department of Preventive and Restorative Dental Sciences, University of California at San Francisco, San Francisco, CA, USA
| | - Stéphane Blouin
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med. Department Hanusch Hospital, Vienna, Austria
| | - Luca Bertinetti
- Center for Molecular Bioengineering, TU Dresden, Dresden, Germany
| | - Markus A Hartmann
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med. Department Hanusch Hospital, Vienna, Austria
| | | | - Richard Weinkamer
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Wolfgang Wagermaier
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Peter Fratzl
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
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12
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Wittig NK, Birkedal H. Bone hierarchical structure: spatial variation across length scales. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2022; 78:305-311. [PMID: 35695104 DOI: 10.1107/s2052520622001524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/08/2022] [Indexed: 06/15/2023]
Abstract
Bone is a complex hierarchical biomineralized material, which is special amongst biominerals because it is replete with cells, namely, osteocytes. While bone has been scrutinized for centuries, many questions remain open and new research hints that the ultrastructure of bone, encompassing both the bone matrix itself and the embedded cell network, is much more heterogeneous than hitherto realized. A number of these new findings have been made thanks to the enormous developments in X-ray imaging that have occurred in recent decades, and there is promise that they will also allow many of the remaining open questions to be addressed. X-ray absorption or phase imaging affords high three-dimensional (3D) resolution and allows traversing the length scales of bone all the way down to the fine details of the lacuno-canalicular network housing the osteocytes. Multimodal X-ray imaging provides combined information covering both the length scales defined by the size of the measured volume and tomographic resolution, as well as those probed by the signal that is measured. In X-ray diffraction computed tomography (XRD-CT), for example, diffraction signals can be reconstructed tomographically, which offers detailed information about the spatial variations in the crystallographic properties of the bone biomineral. Orientational information can be obtained by tensor tomography. The combination of both small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) tensor tomography gives information on the orientation of bone nanostructure and crystals, respectively. These new technical developments promise that great strides towards understanding bone structure can be expected in the near future. In this review, recent findings that have resulted from X-ray imaging are highlighted and speculation is given on what can be expected to follow.
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Affiliation(s)
- Nina K Wittig
- Department of Chemistry and iNANO, Aarhus University, 14 Gustav Wieds Vej, Aarhus 8000, Denmark
| | - Henrik Birkedal
- Department of Chemistry and iNANO, Aarhus University, 14 Gustav Wieds Vej, Aarhus 8000, Denmark
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13
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Effects of Osteocyte Shape on Fluid Flow and Fluid Shear Stress of the Loaded Bone. BIOMED RESEARCH INTERNATIONAL 2022; 2022:3935803. [PMID: 35677099 PMCID: PMC9170394 DOI: 10.1155/2022/3935803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 04/19/2022] [Indexed: 11/17/2022]
Abstract
This study was conducted to better understand the specific behavior of the intraosseous fluid flow. We calculated the number and distribution of bone canaliculi around the osteocytes based on the varying shapes of osteocytes. We then used these calculated parameters and other bone microstructure data to estimate the anisotropy permeability of the lacunar-canalicular network. Poroelastic finite element models of the osteon were established, and the influence of the osteocyte shape on the fluid flow properties of osteons under an axial displacement load was analyzed. Two types of boundary conditions (BC) that might occur in physiological environments were considered on the cement line of the osteon. BC1 allows free fluid passage from the outer elastic restraint boundary, and BC2 is impermeable and allows no free fluid passage from outer displacement constrained boundary. They both have the same inner boundary conditions that allow fluid to pass through. Changes in the osteocyte shape altered the maximum value of pressure gradient (PG), pore pressure (PP), fluid velocity (FV), and fluid shear stress (FSS) relative to the reference model (spherical osteocytes). The maximum PG, PP, FV, and FSS in BC2 were nearly 100% larger than those in BC1, respectively. It is found that the BC1 was closer to the real physiological environment. The fluid flow along different directions in the elongated osteocyte model was more evident than that in other models, which may have been due to the large difference in permeability along different directions. Changes in osteocyte shape significantly affect the degrees of anisotropy of fluid flow and porous media of the osteon. The model presented in this study can accurately quantify fluid flow in the lacunar-canalicular network.
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14
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Suuronen JP, Hesse B, Langer M, Bohner M, Villanova J. Evaluation of imaging setups for quantitative phase contrast nanoCT of mineralized biomaterials. JOURNAL OF SYNCHROTRON RADIATION 2022; 29:843-852. [PMID: 35511016 PMCID: PMC9070718 DOI: 10.1107/s1600577522003137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 03/23/2022] [Indexed: 05/19/2023]
Abstract
X-ray nano-tomography with phase contrast (nanoCT) using synchrotron radiation is a powerful tool to non-destructively investigate 3D material properties at the nanoscale. In large bone lesions, such as severe bone fractures, bone cancer or other diseases, bone grafts substituting the lost bone might be necessary. Such grafts can be of biological origin or be composed of a synthetic bone substitute. The long-term functioning of artificial bone substitutes depends on many factors. Synchrotron nanoCT imaging has great potential to contribute to further the understanding of integration of implants into bone tissue by imaging the spatial interaction between bone tissue and implant, and by accessing the interface between implant material and bone tissue. With this aim, a methodology for evaluating the image quality is presented for in-line phase contrast nanoCT images of bone scaffold samples. A PMMA-embedded tricalcium phosphate scaffold was used with both a closed and an open porosity structure and bone ingrowths as a representative system of three known materials. Parameters such as spatial resolution and signal-to-noise ratio were extracted and used to explore and quantitatively compare the effects of implementation choices in the imaging setup, such as camera technology and imaging energy, on the resulting image quality. Increasing the X-ray energy from 17.5 keV to 29.6 keV leads to a notable improvement in image quality regardless of the camera technology used, with the two tested camera setups performing at a comparable level when the recorded intensity was kept constant.
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Affiliation(s)
- Jussi-Petteri Suuronen
- Xploraytion, Bismarckstrasse 10-12, 10625 Berlin, Germany
- ESRF – The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Bernhard Hesse
- Xploraytion, Bismarckstrasse 10-12, 10625 Berlin, Germany
- ESRF – The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Max Langer
- University of Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, 69621 Lyon, France
- University of Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Marc Bohner
- RMS Foundation, Bischmattstrasse 12, 2544 Bettlach, Switzerland
| | - Julie Villanova
- ESRF – The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
- Correspondence e-mail:
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15
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Bortel E, Grover LM, Eisenstein N, Seim C, Suhonen H, Pacureanu A, Westenberger P, Raum K, Langer M, Peyrin F, Addison O, Hesse B. Interconnectivity Explains High Canalicular Network Robustness between Neighboring Osteocyte Lacunae in Human Bone. ADVANCED NANOBIOMED RESEARCH 2021. [DOI: 10.1002/anbr.202100090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Emely Bortel
- Xploraytion GmbH Bismarckstrasse 10-12 10625 Berlin Germany
| | - Liam M Grover
- School of Chemical Engineering University of Birmingham B15 2TT Birmingham UK
| | - Neil Eisenstein
- School of Chemical Engineering University of Birmingham B15 2TT Birmingham UK
| | - Christian Seim
- Xploraytion GmbH Bismarckstrasse 10-12 10625 Berlin Germany
- Technical University of Berlin: Institute of Optics and Atomic Physics 10623 Berlin Germany
| | - Heikki Suhonen
- University of Helsinki: Department of Physics 00560 Helsinki Finland
| | | | | | - Kay Raum
- Charité—Universitätsmedizin Berlin Corporate Member of Freie Universität Berlin Humboldt-Universität zu Berlinand Berlin Institute of Health BCRT—Berlin Institute of Health Center for Regenerative Therapies 13353 Berlin Germany
| | - Max Langer
- Univ Lyon CNRS 5220Inserm U1294INSA Lyon 69621 Creatis Villeurbanne Cedex France
- Université Grenoble Alpes CNRSUMR 5525 VetAgro SupGrenoble INPTIMC F-38000 Grenoble France
| | - Francoise Peyrin
- ESRF: Experiment Division 38000 Grenoble France
- Univ Lyon CNRS 5220Inserm U1294INSA Lyon 69621 Creatis Villeurbanne Cedex France
| | - Owen Addison
- Faculty of Dentistry Oral and Craniofacial Sciences Kings College SE1 9RT London UK
| | - Bernhard Hesse
- Xploraytion GmbH Bismarckstrasse 10-12 10625 Berlin Germany
- ESRF: Experiment Division 38000 Grenoble France
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16
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Wittig NK, Østergaard M, Palle J, Christensen TEK, Langdahl BL, Rejnmark L, Hauge EM, Brüel A, Thomsen JS, Birkedal H. Opportunities for biomineralization research using multiscale computed X-ray tomography as exemplified by bone imaging. J Struct Biol 2021; 214:107822. [PMID: 34902560 DOI: 10.1016/j.jsb.2021.107822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 12/29/2022]
Abstract
Biominerals typically have complex hierarchical structures traversing many length scales. This makes their structural characterization complicated, since it requires 3D techniques that can probe full specimens at down to nanometer-resolution, a combination that is difficult - if not impossible - to achieve simultaneously. One challenging example is bone, a mineralized tissue with a highly complex architecture that is replete with a network of cells. X-ray computed tomography techniques enable multiscale structural characterization through the combination of various equipment and emerge as promising tools for characterizing biominerals. Using bone as an example, we discuss how combining different X-ray imaging instruments allow characterizing bone structures from the nano- to the organ-scale. In particular, we compare and contrast human and rodent bone, emphasize the importance of the osteocyte lacuno-canalicular network in bone, and finally illustrate how combining synchrotron X-ray imaging with laboratory instrumentation for computed tomography is especially helpful for multiscale characterization of biominerals.
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Affiliation(s)
- Nina Kølln Wittig
- Department of Chemistry and iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark.
| | - Maja Østergaard
- Department of Chemistry and iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Jonas Palle
- Department of Chemistry and iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark
| | - Thorbjørn Erik Køppen Christensen
- Department of Chemistry and iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark; Sino-Danish College (SDC), University of Chinese Academy of Sciences, China
| | - Bente Lomholt Langdahl
- Department of Clinical Medicine - The Department of Endocrinology and Diabetes, Palle Juul-Jensens Boulevard 165, 8200 Aarhus, Denmark
| | - Lars Rejnmark
- Department of Clinical Medicine - The Department of Endocrinology and Diabetes, Palle Juul-Jensens Boulevard 165, 8200 Aarhus, Denmark
| | - Ellen-Margrethe Hauge
- Department of Clinical Medicine - The Department of Rheumatology, Palle Juul-Jensens Boulevard 45, 8200 Aarhus, Denmark
| | - Annemarie Brüel
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark
| | - Jesper Skovhus Thomsen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus, Denmark.
| | - Henrik Birkedal
- Department of Chemistry and iNANO, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus, Denmark.
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17
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Dixit M, Duran‐Ortiz S, Yildirim G, Poudel SB, Louis LD, Bartke A, Schaffler MB, Kopchick JJ, Yakar S. Induction of somatopause in adult mice compromises bone morphology and exacerbates bone loss during aging. Aging Cell 2021; 20:e13505. [PMID: 34811875 PMCID: PMC8672783 DOI: 10.1111/acel.13505] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/31/2021] [Accepted: 09/29/2021] [Indexed: 12/23/2022] Open
Abstract
Somatopause refers to the gradual declines in growth hormone (GH) and insulin‐like growth factor‐1 throughout aging. To define how induced somatopause affects skeletal integrity, we used an inducible GH receptor knockout (iGHRKO) mouse model. Somatopause, induced globally at 6 months of age, resulted in significantly more slender bones in both male and female iGHRKO mice. In males, induced somatopause was associated with progressive expansion of the marrow cavity leading to significant thinning of the cortices, which compromised bone strength. We report progressive declines in osteocyte lacunar number, and increases in lacunar volume, in iGHRKO males, and reductions in lacunar number accompanied by ~20% loss of overall canalicular connectivity in iGHRKO females by 30 months of age. Induced somatopause did not affect mineral/matrix ratio assessed by Raman microspectroscopy. We found significant increases in bone marrow adiposity and high levels of sclerostin, a negative regulator of bone formation in iGHRKO mice. Surprisingly, however, despite compromised bone morphology, osteocyte senescence was reduced in the iGHRKO mice. In this study, we avoided the confounded effects of constitutive deficiency in the GH/IGF‐1 axis on the skeleton during growth, and specifically dissected its effects on the aging skeleton. We show here, for the first time, that induced somatopause compromises bone morphology and the bone marrow environment.
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Affiliation(s)
- Manisha Dixit
- David B. Kriser Dental Center Department of Molecular Pathobiology New York University College of Dentistry New York New York NY USA
| | - Silvana Duran‐Ortiz
- Edison Biotechnology Institute and Dept. of Biomedical Sciences Ohio University Athens OH USA
| | - Godze Yildirim
- David B. Kriser Dental Center Department of Molecular Pathobiology New York University College of Dentistry New York New York NY USA
| | - Sher Bahadur Poudel
- David B. Kriser Dental Center Department of Molecular Pathobiology New York University College of Dentistry New York New York NY USA
| | - Leeann D. Louis
- Department of Biomedical Engineering City College of New York New York NY USA
| | - Andrzej Bartke
- Southern Illinois University School of Medicine Springfield IL USA
| | | | - John J. Kopchick
- Edison Biotechnology Institute and Dept. of Biomedical Sciences Ohio University Athens OH USA
| | - Shoshana Yakar
- David B. Kriser Dental Center Department of Molecular Pathobiology New York University College of Dentistry New York New York NY USA
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18
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Schurman CA, Verbruggen SW, Alliston T. Disrupted osteocyte connectivity and pericellular fluid flow in bone with aging and defective TGF-β signaling. Proc Natl Acad Sci U S A 2021; 118:e2023999118. [PMID: 34161267 PMCID: PMC8237574 DOI: 10.1073/pnas.2023999118] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Skeletal fragility in the elderly does not simply result from a loss of bone mass. However, the mechanisms underlying the concurrent decline in bone mass, quality, and mechanosensitivity with age remain unclear. The important role of osteocytes in these processes and the age-related degeneration of the intricate lacunocanalicular network (LCN) in which osteocytes reside point to a primary role for osteocytes in bone aging. Since LCN complexity severely limits experimental dissection of these mechanisms in vivo, we used two in silico approaches to test the hypothesis that LCN degeneration, due to aging or an osteocyte-intrinsic defect in transforming growth factor beta (TGF-β) signaling (TβRIIocy-/-), is sufficient to compromise essential osteocyte responsibilities of mass transport and exposure to mechanical stimuli. Using reconstructed confocal images of bone with fluorescently labeled osteocytes, we found that osteocytes from aged and TβRIIocy-/- mice had 33 to 45% fewer, and more tortuous, canaliculi. Connectomic network analysis revealed that diminished canalicular density is sufficient to impair diffusion even with intact osteocyte numbers and overall LCN architecture. Computational fluid dynamics predicts that the corresponding drop in shear stress experienced by aged or TβRIIocy-/- osteocytes is highly sensitive to canalicular surface area but not tortuosity. Simulated expansion of the osteocyte pericellular space to mimic osteocyte perilacunar/canalicular remodeling restored predicted shear stress for aged osteocytes to young levels. Overall, these models show how loss of LCN volume through LCN pruning may lead to impaired fluid dynamics and osteocyte exposure to mechanostimulation. Furthermore, osteocytes emerge as targets of age-related therapeutic efforts to restore bone health and function.
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Affiliation(s)
- Charles A Schurman
- Department of Orthopaedic Surgery, University of California, San Francisco, CA 94143
- UC Berkeley-UCSF Graduate Program in Bioengineering, San Francisco, CA 94143
| | - Stefaan W Verbruggen
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom, E1 4NS
- Department of Mechanical Engineering, University of Sheffield, Sheffield, United Kingdom, S1 3JD
- The Insigneo Institute for In Silico Medicine, University of Sheffield, Sheffield, United Kingdom, S1 3JD
- Department of Biomedical Engineering, Columbia University in the City of New York, New York, NY 10027
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California, San Francisco, CA 94143;
- UC Berkeley-UCSF Graduate Program in Bioengineering, San Francisco, CA 94143
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19
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Ahn T, Gidley DW, Thornton AW, Wong-Foy AG, Orr BG, Kozloff KM, Banaszak Holl MM. Hierarchical Nature of Nanoscale Porosity in Bone Revealed by Positron Annihilation Lifetime Spectroscopy. ACS NANO 2021; 15:4321-4334. [PMID: 33619964 PMCID: PMC8176962 DOI: 10.1021/acsnano.0c07478] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Bone is a hierarchical material primarily composed of collagen, water, and mineral that is organized into discrete molecular, nano-, micro-, and macroscale structural components. In contrast to the structural knowledge of the collagen and mineral domains, the nanoscale porosity of bone is poorly understood. In this study, we introduce a well-established pore characterization technique, positron annihilation lifetime spectroscopy (PALS), to probe the nanoscale size and distribution of each component domain by analyzing pore sizes inherent to hydrated bone together with pores generated by successive removal of water and then organic matrix (including collagen and noncollagenous proteins) from samples of cortical bovine femur. Combining the PALS results with simulated pore size distribution (PSD) results from collagen molecule and microfibril structure, we identify pores with diameter of 0.6 nm that suggest porosity within the collagen molecule regardless of the presence of mineral and water. We find that water occupies three larger domain size regions with nominal mean diameters of 1.1, 1.9, and 4.0 nm-spaces that are hypothesized to associate with intercollagen molecular spaces, terminal segments (d-spacing) within collagen microfibrils, and interface spacing between collagen and mineral structure, respectively. Subsequent removal of the organic matrix determines a structural pore size of 5-6 nm for deproteinized bone-suggesting the average spacing between mineral lamella. An independent method to deduce the average mineral spacing from specific surface area (SSA) measurements of the deproteinized sample is presented and compared with the PALS results. Together, the combined PALS and SSA results set a range on the mean mineral lamella thickness of 4-8 nm.
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20
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Chang B, Liu X. Osteon: Structure, Turnover, and Regeneration. TISSUE ENGINEERING PART B-REVIEWS 2021; 28:261-278. [PMID: 33487116 DOI: 10.1089/ten.teb.2020.0322] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bone is composed of dense and solid cortical bone and honeycomb-like trabecular bone. Although cortical bone provides the majority of mechanical strength for a bone, there are few studies focusing on cortical bone repair or regeneration. Osteons (the Haversian system) form structural and functional units of cortical bone. In recent years, emerging evidences have shown that the osteon structure (including osteocytes, lamellae, lacunocanalicular network, and Haversian canals) plays critical roles in bone mechanics and turnover. Therefore, reconstruction of the osteon structure is crucial for cortical bone regeneration. This article provides a systematic summary of recent advances in osteons, including the structure, function, turnover, and regenerative strategies. First, the hierarchical structure of osteons is illustrated and the critical functions of osteons in bone dynamics are introduced. Next, the modeling and remodeling processes of osteons at a cellular level and the turnover of osteons in response to mechanical loading and aging are emphasized. Furthermore, several bioengineering approaches that were recently developed to recapitulate the osteon structure are highlighted. Impact statement This review provides a comprehensive summary of recent advances in osteons, especially the roles in bone formation, remodeling, and regeneration. Besides introducing the hierarchical structure and critical functions of osteons, we elucidate the modeling and remodeling of osteons at a cellular level. Specifically, we highlight the bioengineering approaches that were recently developed to mimic the hierarchical structure of osteons. We expect that this review will provide informative insights and attract increasing attentions in orthopedic community, shedding light on cortical bone regeneration in the future.
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Affiliation(s)
- Bei Chang
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA
| | - Xiaohua Liu
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA
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21
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Haridy Y, Osenberg M, Hilger A, Manke I, Davesne D, Witzmann F. Bone metabolism and evolutionary origin of osteocytes: Novel application of FIB-SEM tomography. SCIENCE ADVANCES 2021; 7:eabb9113. [PMID: 33789889 PMCID: PMC8011976 DOI: 10.1126/sciadv.abb9113] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 02/11/2021] [Indexed: 06/10/2023]
Abstract
Lacunae and canaliculi spaces of osteocytes are remarkably well preserved in fossilized bone and serve as an established proxy for bone cells. The earliest bone in the fossil record is acellular (anosteocytic), followed by cellular (osteocytic) bone in the jawless relatives of jawed vertebrates, the osteostracans, about 400 million years ago. Virtually nothing is known about the physiological pressures that would have initially favored osteocytic over anosteocytic bone. We apply focused ion beam-scanning electron microscopy tomography combined with machine learning for cell detection and segmentation to image fossil cell spaces. Novel three-dimensional high-resolution images reveal areas of low density around osteocyte lacunae and their canaliculi in osteostracan bone. This provides evidence for demineralization that would have occurred in vivo as part of osteocytic osteolysis, a mechanism of mineral homeostasis, supporting the hypothesis that a physiological demand for phosphorus was the principal driver in the initial evolution of osteocytic bone.
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Affiliation(s)
- Yara Haridy
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany.
| | - Markus Osenberg
- Helmholtz Centre for Materials and Energy (HZB), Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - André Hilger
- Helmholtz Centre for Materials and Energy (HZB), Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Ingo Manke
- Helmholtz Centre for Materials and Energy (HZB), Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Donald Davesne
- Department of Earth Sciences, University of Oxford, OX1 3AN Oxford, UK
- Institut de Systématique, Évolution, Biodiversité (UMR 7205), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, 75005 Paris, France
| | - Florian Witzmann
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
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22
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The mechanoresponse of bone is closely related to the osteocyte lacunocanalicular network architecture. Proc Natl Acad Sci U S A 2020; 117:32251-32259. [PMID: 33288694 PMCID: PMC7768754 DOI: 10.1073/pnas.2011504117] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The explanation of how bone senses and adapts to mechanical stimulation still relies on hypotheses. The fluid flow hypothesis claims that a load-induced fluid flow through the lacunocanalicular network can be sensed by osteocytes, which reside within the network structure. We show that considering the network architecture results in a better prediction of bone remodeling than mechanical strain alone. This was done by calculating the fluid flow through the lacunocanalicular network in bone volumes covering the complete cross-sections of mouse tibiae, which underwent controlled in vivo loading. The established relationship between mechanosensitivity and network architecture in individual animals implies possibilities for patient-specific therapies. A new connectomics approach to analyze lacunocanalicular network properties is necessary to understand skeletal mechanobiology. Organisms rely on mechanosensing mechanisms to adapt to changes in their mechanical environment. Fluid-filled network structures not only ensure efficient transport but can also be employed for mechanosensation. The lacunocanalicular network (LCN) is a fluid-filled network structure, which pervades our bones and accommodates a cell network of osteocytes. For the mechanism of mechanosensation, it was hypothesized that load-induced fluid flow results in forces that can be sensed by the cells. We use a controlled in vivo loading experiment on murine tibiae to test this hypothesis, whereby the mechanoresponse was quantified experimentally by in vivo micro-computed tomography (µCT) in terms of formed and resorbed bone volume. By imaging the LCN using confocal microscopy in bone volumes covering the entire cross-section of mouse tibiae and by calculating the fluid flow in the three-dimensional (3D) network, we could perform a direct comparison between predictions based on fluid flow velocity and the experimentally measured mechanoresponse. While local strain distributions estimated by finite-element analysis incorrectly predicts preferred bone formation on the periosteal surface, we demonstrate that additional consideration of the LCN architecture not only corrects this erroneous bias in the prediction but also explains observed differences in the mechanosensitivity between the three investigated mice. We also identified the presence of vascular channels as an important mechanism to locally reduce fluid flow. Flow velocities increased for a convergent network structure where all of the flow is channeled into fewer canaliculi. We conclude that, besides mechanical loading, LCN architecture should be considered as a key determinant of bone adaptation.
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Palle J, Wittig NK, Kubec A, Niese S, Rosenthal M, Burghammer M, Grünewald TA, Birkedal H. Nanobeam X-ray fluorescence and diffraction computed tomography on human bone with a resolution better than 120 nm. J Struct Biol 2020; 212:107631. [DOI: 10.1016/j.jsb.2020.107631] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 09/15/2020] [Accepted: 09/19/2020] [Indexed: 12/11/2022]
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Schemenz V, Gjardy A, Chamasemani FF, Roschger A, Roschger P, Zaslansky P, Helfen L, Burghammer M, Fratzl P, Weinkamer R, Brunner R, Willie BM, Wagermaier W. Heterogeneity of the osteocyte lacuno-canalicular network architecture and material characteristics across different tissue types in healing bone. J Struct Biol 2020; 212:107616. [PMID: 32920138 DOI: 10.1016/j.jsb.2020.107616] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 09/01/2020] [Accepted: 09/04/2020] [Indexed: 02/08/2023]
Abstract
Various tissue types, including fibrous connective tissue, bone marrow, cartilage, woven and lamellar bone, coexist in healing bone. Similar to most bone tissue type, healing bone contains a lacuno-canalicular network (LCN) housing osteocytes. These cells are known to orchestrate bone remodeling in healthy bone by sensing mechanical strains and translating them into biochemical signals. The structure of the LCN is hypothesized to influence mineralization processes. Hence, the aim of the present study was to visualize and match spatial variations in the LCN topology with mineral characteristics, within and at the interfaces of the different tissue types that comprise healing bone. We applied a correlative multi-method approach to visualize the LCN architecture and quantify mineral particle size and orientation within healing femoral bone in a mouse osteotomy model (26 weeks old C57BL/6 mice). This approach revealed structural differences across several length scales during endochondral ossification within the following regions: calcified cartilage, bony callus, cortical bone and a transition zone between the cortical and callus region analyzed 21 days after the osteotomy. In this transition zone, we observed a continuous convergence of mineral characteristics and osteocyte lacunae shape as well as discontinuities in the lacunae volume and LCN connectivity. The bony callus exhibits a 34% higher lacunae number density and 40% larger lacunar volume compared to cortical bone. The presented correlations between LCN architecture and mineral characteristics improves our understanding of how bone develops during healing and may indicate a contribution of osteocytes to bone (re)modeling.
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Affiliation(s)
- Victoria Schemenz
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - André Gjardy
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
| | | | - Andreas Roschger
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany; Paris-Lodron-University of Salzburg, Department of Chemistry and Physics of Materials, Salzburg, Austria
| | - Paul Roschger
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of ÖGK and AUVA Trauma Centre Meidling, 1st Medical Department, Hanusch Hospital, Vienna, Austria
| | - Paul Zaslansky
- Department for Restorative and Preventive Dentistry, Charité-Universitaetsmedizin Berlin, Berlin 14197, Germany
| | - Lukas Helfen
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology, D-76021 Karlsruhe, Germany; Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex 9, France
| | | | - Peter Fratzl
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Richard Weinkamer
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Roland Brunner
- Materials Center Leoben Forschung GmbH, 8700 Leoben, Austria
| | - Bettina M Willie
- Research Centre, Shriners Hospitals for Children-Canada, Department of Pediatric Surgery, McGill University, 1003 Decarie Blvd, Montreal, Quebec H4A 0A9, Canada
| | - Wolfgang Wagermaier
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Am Mühlenberg 1, 14476 Potsdam, Germany.
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Ellipsoidal mesoscale mineralization pattern in human cortical bone revealed in 3D by plasma focused ion beam serial sectioning. J Struct Biol 2020; 212:107615. [PMID: 32927057 DOI: 10.1016/j.jsb.2020.107615] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 08/31/2020] [Accepted: 09/04/2020] [Indexed: 01/24/2023]
Abstract
Visualizing bone mineralization and collagen fibril organization at intermediate scales between the nanometer and the hundreds of microns range, is still an important challenge. Similarly, visualizing cellular components which locally affect the tissue structure requires a precision of a few tens of nanometers at maximum while spanning several tens of micrometers. In the last decade, gallium focused ion beam (FIB) equipped with a scanning electron microscope (SEM) proved to be an extremely valuable structural tool to meet those ends. In this study, we assess the capability of a recent plasma FIB-SEM technology which provides a potential increase in measurement speed over gallium FIB-SEM, thus paving the way to larger volume analysis. Nanometer-scale layers of demineralized and mineralized unstained human femoral lamellar bone were sequentially sectioned over volumes of 6-16,000 μm3. Analysis of mineralized tissue revealed prolate ellipsoidal mineral clusters measuring approximately 1.1 µm in length by 700 nm at their maximum diameter. Those features, suggested by others in high resolution studies, appear here as a ubiquitous motif in mineralized lamellar bone over thousands of microns cubed, suggesting a heterogeneous and yet regular pattern of mineral deposition past the single collagen fibril level. This large scale view retained sufficient resolution to visualize the collagen fibrils while also partly visualizing the lacuno-canalicular network in three-dimensions. These findings are strong evidence for suitability of PFIB as a bone analysis tool and the need to revisit bone mineralization over multi-length scales with mineralized tissue.
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Moreno-Jiménez I, Cipitria A, Sánchez-Herrero A, van Tol AF, Roschger A, Lahr CA, McGovern JA, Hutmacher DW, Fratzl P. Human and mouse bones physiologically integrate in a humanized mouse model while maintaining species-specific ultrastructure. SCIENCE ADVANCES 2020; 6:6/44/eabb9265. [PMID: 33115741 PMCID: PMC7608795 DOI: 10.1126/sciadv.abb9265] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 08/31/2020] [Indexed: 05/07/2023]
Abstract
Humanized mouse models are increasingly studied to recapitulate human-like bone physiology. While human and mouse bone architectures differ in multiple scales, the extent to which chimeric human-mouse bone physiologically interacts and structurally integrates remains unknown. Here, we identify that humanized bone is formed by a mosaic of human and mouse collagen, structurally integrated within the same bone organ, as shown by immunohistochemistry. Combining this with materials science techniques, we investigate the extracellular matrix of specific human and mouse collagen regions. We show that human-like osteocyte lacunar-canalicular network is retained within human collagen regions and is distinct to that of mouse tissue. This multiscale analysis shows that human and mouse tissues physiologically integrate into a single, functional bone tissue while maintaining their species-specific ultrastructural differences. These results offer an original method to validate and advance tissue-engineered human-like bone in chimeric animal models, which grow to be eloquent tools in biomedical research.
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Affiliation(s)
- I Moreno-Jiménez
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - A Cipitria
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - A Sánchez-Herrero
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - A F van Tol
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - A Roschger
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - C A Lahr
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - J A McGovern
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - D W Hutmacher
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany.
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - P Fratzl
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany.
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Wittig NK, Palle J, Østergaard M, Frølich S, Birkbak ME, Spiers KM, Garrevoet J, Birkedal H. Bone Biomineral Properties Vary across Human Osteonal Bone. ACS NANO 2019; 13:12949-12956. [PMID: 31613594 DOI: 10.1021/acsnano.9b05535] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The biomineralization of bone remains a puzzle. During Haversian remodeling in the dense human cortical bone, osteoclasts excavate a tunnel that is then filled in by osteoblasts with layers of bone of varying fibril orientations, resulting in a lamellar motif. Such bone represents an excellent possibility to increase our understanding of bone as a material as well as bone biomineralization by studying spatio/temporal variations in the biomineral across an osteon. To this end, fluorescence computed tomography and diffraction scattering computed tomography with sub-micrometer resolution is applied to obtain position resolved fluorescence spectra and diffraction patterns in a 3D volume. The microstructural properties of the apatite biomineral are not homogeneous but depend critically on the time point at which it was laid down. This indicates that the nature of bone biomineral is highly dependent on the microenvironment during bone formation and remodeling.
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Affiliation(s)
- Nina K Wittig
- Department of Chemistry and iNANO , Aarhus University , Gustav Wieds Vej 14 , 8000 Aarhus C , Denmark
| | - Jonas Palle
- Department of Chemistry and iNANO , Aarhus University , Gustav Wieds Vej 14 , 8000 Aarhus C , Denmark
| | - Maja Østergaard
- Department of Chemistry and iNANO , Aarhus University , Gustav Wieds Vej 14 , 8000 Aarhus C , Denmark
| | - Simon Frølich
- Department of Chemistry and iNANO , Aarhus University , Gustav Wieds Vej 14 , 8000 Aarhus C , Denmark
| | - Mie E Birkbak
- Department of Chemistry and iNANO , Aarhus University , Gustav Wieds Vej 14 , 8000 Aarhus C , Denmark
| | | | - Jan Garrevoet
- DESY Photon Science , Notkestr. 85 , D-22607 Hamburg , Germany
| | - Henrik Birkedal
- Department of Chemistry and iNANO , Aarhus University , Gustav Wieds Vej 14 , 8000 Aarhus C , Denmark
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