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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 2024:10.1007/s11914-024-00877-z. [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] [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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Weiner S, Shahar R. Vertebrate mineralized tissues: A modular structural analysis. Acta Biomater 2024; 179:1-12. [PMID: 38561073 DOI: 10.1016/j.actbio.2024.03.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/04/2024]
Abstract
Vertebrate mineralized tissues, present in bones, teeth and scales, have complex 3D hierarchical structures. As more of these tissues are characterized in 3D using mainly FIB SEM at a resolution that reveals the mineralized collagen fibrils and their organization into collagen fibril bundles, highly complex and diverse structures are being revealed. In this perspective we propose an approach to analyzing these tissues based on the presence of modular structures: material textures, pore shapes and sizes, as well as extents of mineralization. This modular approach is complimentary to the widely used hierarchical approach for describing these mineralized tissues. We present a series of case studies that show how some of the same structural modules can be found in different mineralized tissues, including in bone, dentin and scales. The organizations in 3D of the various structural modules in different tissues may differ. This approach facilitates the framing of basic questions such as: are the spatial relations between modular structures the same or similar in different mineralized tissues? Do tissues with similar sets of modules carry out similar functions or can similar functions be carried out using a different set of modular structures? Do mineralized tissues with similar sets of modules have a common developmental or evolutionary pathway? STATEMENT OF SIGNIFICANCE: 3D organization studies of diverse vertebrate mineralized tissues are revealing detailed, but often confusing details about the material textures, the arrangements of pores and differences in the extent of mineralization within a tissue. The widely used hierarchical scheme for describing such organizations does not adequately provide a basis for comparing these tissues, or addressing issues such as structural components thought to be characteristic of bone, being present in dermal tissues and so on. The classification scheme we present is based on identifying structural components within a tissue that can then be systematically compared to other vertebrate mineralized tissues. We anticipate that this classification approach will provide insights into structure-function relations, as well as the evolution of these tissues.
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Affiliation(s)
- Steve Weiner
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot 7610001, Israel.
| | - Ron Shahar
- Faculty of Agriculture Food & Environment, Koret School of Veterinary Medicine, Hebrew University Jerusalem, P.O.B. 12, Rehovot 7610001, Israel
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André G, Chretien A, Demoulin A, Beersaerts M, Docquier PL, Behets C. Col1A-2 Mutation in Osteogenesis Imperfecta Mice Contributes to Long Bone Fragility by Modifying Cell-Matrix Organization. Int J Mol Sci 2023; 24:17010. [PMID: 38069332 PMCID: PMC10707465 DOI: 10.3390/ijms242317010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/24/2023] [Accepted: 11/28/2023] [Indexed: 12/18/2023] Open
Abstract
Osteogenesis imperfecta (OI) is a rare congenital bone dysplasia generally caused by a mutation of one of the type I collagen genes and characterized by low bone mass, numerous fractures, and bone deformities. The collagen organization and osteocyte lacuna arrangement were investigated in the long bones of 17-week-old wildtype (WT, n = 17) and osteogenesis imperfecta mice (OIM, n = 16) that is a validated model of severe human OI in order to assess their possible role in bone fragility. Fractures were counted after in vivo scanning at weeks 5, 11, and 17. Humerus, femur, and tibia diaphyses from both groups were analyzed ex vivo with pQCT, polarized and ordinary light histology, and Nano-CT. The fractures observed in the OIM were more numerous in the humerus and femur than in the tibia, whereas the quantitative bone parameters were altered in different ways among these bones. Collagen fiber organization appeared disrupted, with a lower birefringence in OIM than WT bones, whereas the osteocyte lacunae were more numerous, more spherical, and not aligned in a lamellar pattern. These modifications, which are typical of immature and less mechanically competent bone, attest to the reciprocal alteration of collagen matrix and osteocyte lacuna organization in the OIM, thereby contributing to bone fragility.
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Affiliation(s)
- Grégoire André
- Pole of Morphology, Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Brussels, Belgium; (G.A.); (A.C.); (A.D.); (M.B.)
| | - Antoine Chretien
- Pole of Morphology, Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Brussels, Belgium; (G.A.); (A.C.); (A.D.); (M.B.)
| | - Antoine Demoulin
- Pole of Morphology, Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Brussels, Belgium; (G.A.); (A.C.); (A.D.); (M.B.)
| | - Mélanie Beersaerts
- Pole of Morphology, Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Brussels, Belgium; (G.A.); (A.C.); (A.D.); (M.B.)
| | - Pierre-Louis Docquier
- Neuromusculoskeletal Lab, Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Brussels, Belgium;
| | - Catherine Behets
- Pole of Morphology, Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Brussels, Belgium; (G.A.); (A.C.); (A.D.); (M.B.)
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Liu Z, Niu Y, Fu Z, Dean M, Fu Z, Hu Y, Zou Z. 3D relationship between hierarchical canal network and gradient mineralization of shark tooth osteodentin. Acta Biomater 2023; 168:185-197. [PMID: 37451657 DOI: 10.1016/j.actbio.2023.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 06/25/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Osteodentin is a dominant mineralized collagenous tissue in the teeth of many fishes, with structural and histological characteristics resembling those of bone. Osteodentin, like bone, comprises osteons as basic structural building blocks, however, it lacks the osteocytes and the lacuno-canalicular network (LCN), which are known to play critical roles in controlling the mineralization of the collagenous matrix in bone. Although numerous vascular canals exist in osteodentin, their role in tooth maturation and the matrix mineralization process remain poorly understood. Here, high resolution micro-computed tomography (micro-CT) and focused ion beam-scanning electron microscopy (FIB-SEM) were used to obtain 3D structural information of osteodentin in shark teeth at multiple scales. We observed a complex 3D network of primary canals with a diameter ranging from ∼10 µm to ∼120 µm, where the canals are surrounded by osteon-like concentric layers of lamellae, with 'interosteonal' tissue intervening between neighboring osteons. In addition, numerous hierarchically branched secondary canals extended radially from the primary canals into the interosteonal tissue, decreasing in diameter from ∼10 µm to hundreds of nanometers. Interestingly, the mineralization degree increases from the periphery of primary canals into the interosteonal tissue, suggesting that mineralization begins in the interosteonal tissue. Correspondingly, the hardness and elastic modulus of the interosteonal tissue are higher than those of the osteonal tissue. These results demonstrate that the 3D hierarchical canal network is positioned to play a critical role in controlling the gradient mineralization of osteodentin, also providing valuable insight into the formation of mineralized collagenous tissue without osteocytes and LCN. STATEMENT OF SIGNIFICANCE: Bone is a composite material with versatile mechanical properties. Osteocytes and their lacuno-canalicular network (LCN) are known to play critical roles during formation of human bone. However, the bone and osteodentin of many fishes, although lacking osteocytes and LCN, exhibit similar osteon-like structure and mechanical functions. Here, using various high resolution 3D characterization techniques, we reveal that the 3D network of primary canals and numerous hierarchically branched secondary canals correlate with the mineralization gradient and micromechanical properties of osteonal and interosteonal tissues of shark tooth osteodentin. This work significantly improves our understanding of the construction of bone-like mineralized tissue without osteocytes and LCN, and provides inspirations for the fabrication of functional materials with hierarchical structure.
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Affiliation(s)
- Zhuanfei Liu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Yunya Niu
- State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, China
| | - Zeyao Fu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Mason Dean
- Department of Infectious Diseases & Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong, China
| | - Zhengyi Fu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
| | - Yongming Hu
- School of Microelectronics, Hubei University, Wuhan 430062, Hubei, China..
| | - Zhaoyong Zou
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.; Hubei Longzhong Laboratory, Wuhan University of Technology Xiangyang Demonstration Zone, Xiangyang 441000, China.
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Wüster J, Hesse B, Rothweiler R, Bortel E, Gross C, Bakhtiyari S, King A, Boller E, Gerber J, Rendenbach C, Fretwurst T, Preissner S, Heiland M, Nelson K, Nahles S. Comparison of the 3D-microstructure of human alveolar and fibula bone in microvascular autologous bone transplantation: a synchrotron radiation μ-CT study. Front Bioeng Biotechnol 2023; 11:1169385. [PMID: 37691907 PMCID: PMC10486015 DOI: 10.3389/fbioe.2023.1169385] [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: 02/19/2023] [Accepted: 08/01/2023] [Indexed: 09/12/2023] Open
Abstract
Introduction: Autologous bone transplantation is successfully used in reconstructive surgery of large/critical-sized bone defects, whereby the microvascular free fibula flap is still regarded as the gold standard for the reconstruction of such defects in the head and neck region. Here, we report the morphological and lacunar properties of patient-paired bone samples from eight patients from the jaw (AB; recipient site) and the fibula (FB; donor site) on the micron length-scale using Synchrotron µ-CT. Insights into differences and similarities between these bone structures could offer a better understanding of the underlying mechanism for successful surgical outcomes and might clear the path for optimized, nature-inspired bone scaffold designs. Methods: Spatial vessel-pore arrangements, bone morphology, fluid-simulation derived permeability tensor, osteocyte lacunar density, and lacunar morphology are compared. Results: The orientation of the vessel system indicates a homogenous vessel orientation for AB and FB. The average mineral distance (50%) to the closest vessel boundary is higher in AB than in FB (the mean is 96 μm for AB vs. 76 μm for FB; p = 0.021). Average osteocyte lacunar density is found to be higher in AB than in FB (mean 22,874 mm3 vs. 19,376 mm3 for FB; p = 0.038), which might compensate for the high distance from the mineral to the nearest vessel. No significant differences in lacunar volume are found between paired AB and FB. Discussion: A comparable vessel network and similar distribution of vessel porosity between AB and FB may allow the FB graft to exhibit a high regeneration potential when connected to AB, and this might correlate with a high osteoinductive and osteoconductive potential of FB when connected to AB. Since widely used and potent synthetic bone grafts exist, new insight into the bone structure of well-established autologous bone grafts, such as the free fibula flap, could help to improve the performance of such materials and therefore the design of 3D scaffolds.
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Affiliation(s)
- Jonas Wüster
- Department of Oral and Maxillofacial Surgery, Berlin Institute of Health, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Bernhard Hesse
- Xploraytion GmbH, Berlin, Germany
- European Synchrotron Radiation Facility, Grenoble, France
| | - Rene Rothweiler
- Department of Oral- and Craniomaxillofacial Surgery, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | | | - Christian Gross
- Department of Oral- and Craniomaxillofacial Surgery, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | | | | | - Elodie Boller
- European Synchrotron Radiation Facility, Grenoble, France
| | | | - Carsten Rendenbach
- Department of Oral and Maxillofacial Surgery, Berlin Institute of Health, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Tobias Fretwurst
- Department of Oral- and Craniomaxillofacial Surgery, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Saskia Preissner
- Department of Oral and Maxillofacial Surgery, Berlin Institute of Health, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Max Heiland
- Department of Oral and Maxillofacial Surgery, Berlin Institute of Health, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Katja Nelson
- Department of Oral- and Craniomaxillofacial Surgery, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany
| | - Susanne Nahles
- Department of Oral and Maxillofacial Surgery, Berlin Institute of Health, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
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6
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Buccino F, Zagra L, Longo E, D'Amico L, Banfi G, Berto F, Tromba G, Vergani LM. Osteoporosis and Covid-19: Detected similarities in bone lacunar-level alterations via combined AI and advanced synchrotron testing. MATERIALS & DESIGN 2023; 231:112087. [PMID: 37323219 PMCID: PMC10257887 DOI: 10.1016/j.matdes.2023.112087] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/03/2023] [Accepted: 06/09/2023] [Indexed: 06/17/2023]
Abstract
While advanced imaging strategies have improved the diagnosis of bone-related pathologies, early signs of bone alterations remain difficult to detect. The Covid-19 pandemic has brought attention to the need for a better understanding of bone micro-scale toughening and weakening phenomena. This study used an artificial intelligence-based tool to automatically investigate and validate four clinical hypotheses by examining osteocyte lacunae on a large scale with synchrotron image-guided failure assessment. The findings indicate that trabecular bone features exhibit intrinsic variability related to external loading, micro-scale bone characteristics affect fracture initiation and propagation, osteoporosis signs can be detected at the micro-scale through changes in osteocyte lacunar features, and Covid-19 worsens micro-scale porosities in a statistically significant manner similar to the osteoporotic condition. Incorporating these findings with existing clinical and diagnostic tools could prevent micro-scale damages from progressing into critical fractures.
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Affiliation(s)
- Federica Buccino
- Department of Mechanical Engineering, Politecnico di Milano, 20156, Italy
| | - Luigi Zagra
- I.R.C.C.S Ospedale Galeazzi - Sant'Ambrogio, Milano 20157, Italy
| | - Elena Longo
- Elettra-Sincrotrone Trieste SCpA, Basovizza, Trieste 34149, Italy
| | - Lorenzo D'Amico
- Elettra-Sincrotrone Trieste SCpA, Basovizza, Trieste 34149, Italy
| | - Giuseppe Banfi
- I.R.C.C.S Ospedale Galeazzi - Sant'Ambrogio, Milano 20157, Italy
| | - Filippo Berto
- Università La Sapienza, Rome 00185, Italy
- NTNU, Norway
| | - Giuliana Tromba
- Elettra-Sincrotrone Trieste SCpA, Basovizza, Trieste 34149, Italy
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Guo Q, Chen N, Qian C, Qi C, Noller K, Wan M, Liu X, Zhang W, Cahan P, Cao X. Sympathetic Innervation Regulates Osteocyte-Mediated Cortical Bone Resorption during Lactation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2207602. [PMID: 37186379 PMCID: PMC10288263 DOI: 10.1002/advs.202207602] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/13/2023] [Indexed: 05/17/2023]
Abstract
Bone undergoes constant remodeling by osteoclast bone resorption coupled with osteoblast bone formation at the bone surface. A third major cell type in the bone is osteocytes, which are embedded in the matrix, are well-connected to the lacunar network, and are believed to act as mechanical sensors. Here, it is reported that sympathetic innervation directly regulates lacunar osteocyte-mediated bone resorption inside cortical bone. It is found that sympathetic activity is elevated in different mouse models of bone loss, including lactation, ovariectomy, and glucocorticoid treatment. Further, during lactation elevated sympathetic outflow induces netrin-1 expression by osteocytes to further promote sympathetic nerve sprouting in the cortical bone endosteum in a feed-forward loop. Depletion of tyrosine hydroxylase-positive (TH+ ) sympathetic nerves ameliorated osteocyte-mediated perilacunar bone resorption in lactating mice. Moreover, norepinephrine activates β-adrenergic receptor 2 (Adrb2) signaling to promote secretion of extracellular vesicles (EVs) containing bone-degrading enzymes for perilacunar bone resorption and inhibit osteoblast differentiation. Importantly, osteocyte-specific deletion of Adrb2 or treatment with a β-blocker results in lower bone resorption in lactating mice. Together, these findings show that the sympathetic nervous system promotes osteocyte-driven bone loss during lactation, likely as an adaptive response to the increased energy and mineral demands of the nursing mother.
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Affiliation(s)
- Qiaoyue Guo
- Department of Orthopedic SurgeryJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Ningrong Chen
- Department of Orthopedic SurgeryJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Cheng Qian
- Department of Orthopedic SurgeryJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Cheng Qi
- Department of Orthopedic SurgeryJohns Hopkins University School of MedicineBaltimoreMD21205USA
- Department of Biomedical EngineeringJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Kathleen Noller
- Department of Biomedical EngineeringJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Mei Wan
- Department of Orthopedic SurgeryJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Xiaonan Liu
- Department of Orthopedic SurgeryJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Weixin Zhang
- Department of Orthopedic SurgeryJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Patrick Cahan
- Department of Biomedical EngineeringJohns Hopkins University School of MedicineBaltimoreMD21205USA
| | - Xu Cao
- Department of Orthopedic SurgeryJohns Hopkins University School of MedicineBaltimoreMD21205USA
- Department of Biomedical EngineeringJohns Hopkins University School of MedicineBaltimoreMD21205USA
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8
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Kim MK, Paek K, Woo SM, Kim JA. Bone-on-a-Chip: Biomimetic Models Based on Microfluidic Technologies for Biomedical Applications. ACS Biomater Sci Eng 2023. [PMID: 37183366 DOI: 10.1021/acsbiomaterials.3c00066] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
With the increasing importance of preclinical evaluation of newly developed drugs or treatments, in vitro organ or disease models are necessary. Although various organ-specific on-chip (organ-on-a-chip, or OOC) systems have been developed as emerging in vitro models, bone-on-a-chip (BOC) systems that recapitulate the bone microenvironment have been less developed or reviewed compared with other OOCs. The bone is one of the most dynamic organs and undergoes continuous remodeling throughout its lifetime. The aging population is growing worldwide, and healthcare costs are rising rapidly. Since in vitro BOC models that recapitulate native bone niches and pathological features can be important for studying the underlying mechanism of orthopedic diseases and predicting drug responses in preclinical trials instead of in animals, the development of biomimetic BOCs with high efficiency and fidelity will be accelerated further. Here, we review recently engineered BOCs developed using various microfluidic technologies and investigate their use to model the bone microenvironment. We have also explored various biomimetic strategies based on biological, geometrical, and biomechanical cues for biomedical applications of BOCs. Finally, we addressed the limitations and challenging issues of current BOCs that should be overcome to obtain more acceptable BOCs in the biomedical and pharmaceutical industries.
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Affiliation(s)
- Min Kyeong Kim
- Center for Scientific Instrumentation, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
| | - Kyurim Paek
- Center for Scientific Instrumentation, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
- Program in Biomicro System Technology, Korea University, Seoul 02841, Republic of Korea
| | - Sang-Mi Woo
- Center for Scientific Instrumentation, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
| | - Jeong Ah Kim
- Center for Scientific Instrumentation, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
- Department of Bio-Analytical Science, University of Science and Technology, Daejeon 34113, Republic of Korea
- Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul 06973, Republic of Korea
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9
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Buccino F, Cervellera F, Ghidini M, Marini R, Bagherifard S, Vergani LM. Isolating the Role of Bone Lacunar Morphology on Static and Fatigue Fracture Progression through Numerical Simulations. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1931. [PMID: 36903046 PMCID: PMC10004234 DOI: 10.3390/ma16051931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 02/13/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Currently, the onset of bone damage and the interaction of cracks with the surrounding micro-architecture are still black boxes. With the motivation to address this issue, our research targets isolating lacunar morphological and densitometric effects on crack advancement under both static and cyclic loading conditions by implementing static extended finite element models (XFEM) and fatigue analyses. The effect of lacunar pathological alterations on damage initiation and progression is evaluated; the results indicate that high lacunar density considerably reduces the mechanical strength of the specimens, resulting as the most influencing parameter among the studied ones. Lacunar size has a lower effect on mechanical strength, reducing it by 2%. Additionally, specific lacunar alignments play a key role in deviating the crack path, eventually slowing its progression. This could shed some light on evaluating the effects of lacunar alterations on fracture evolution in the presence of pathologies.
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10
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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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Li Q, Wang R, Zhang Z, Wang H, Lu X, Zhang J, Kong APS, Tian XY, Chan HF, Chung ACK, Cheng JCY, Jiang Q, Lee WYW. Sirt3 mediates the benefits of exercise on bone in aged mice. Cell Death Differ 2023; 30:152-167. [PMID: 36153410 PMCID: PMC9883264 DOI: 10.1038/s41418-022-01053-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 08/16/2022] [Accepted: 08/22/2022] [Indexed: 02/01/2023] Open
Abstract
Exercise in later life is important for bone health and delays the progression of osteoporotic bone loss. Osteocytes are the major bone cells responsible for transforming mechanical stimuli into cellular signals through their highly specialized lacunocanalicular networks (LCN). Osteocyte activity and LCN degenerate with aging, thus might impair the effectiveness of exercise on bone health; however, the underlying mechanism and clinical implications remain elusive. Herein, we showed that deletion of Sirt3 in osteocytes could impair the formation of osteocyte dendritic processes and inhibit bone gain in response to exercise in vivo. Mechanistic studies revealed that Sirt3 regulates E11/gp38 through the protein kinase A (PKA)/cAMP response element-binding protein (CREB) signaling pathway. Additionally, the Sirt3 activator honokiol enhanced the sensitivity of osteocytes to fluid shear stress in vitro, and intraperitoneal injection of honokiol reduced bone loss in aged mice in a dose-dependent manner. Collectively, Sirt3 in osteocytes regulates bone mass and mechanical responses through the regulation of E11/gp38. Therefore, targeting Sirt3 could be a novel therapeutic strategy to prevent age-related bone loss and augment the benefits of exercise on the senescent skeleton.
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Affiliation(s)
- Qiangqiang Li
- Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- State Key Laboratory of Pharmaceutical Biotechnology, Division of Sports Medicine and Adult Reconstructive Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, PR China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China
| | - Rongliang Wang
- Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China
- SH Ho Scoliosis Research Laboratory, Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, The Chinese University of Hong Kong, Hong Kong, China
| | - Zhe Zhang
- Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China
- SH Ho Scoliosis Research Laboratory, Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, The Chinese University of Hong Kong, Hong Kong, China
| | - Haixing Wang
- Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiaomin Lu
- Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Jiajun Zhang
- Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- SH Ho Scoliosis Research Laboratory, Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, The Chinese University of Hong Kong, Hong Kong, China
| | - Alice Pik-Shan Kong
- Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiao Yu Tian
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Hon-Fai Chan
- Institute for Tissue Engineering and Regenerative Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Arthur Chi-Kong Chung
- Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
| | - Jack Chun-Yiu Cheng
- Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- SH Ho Scoliosis Research Laboratory, Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, The Chinese University of Hong Kong, Hong Kong, China
| | - Qing Jiang
- State Key Laboratory of Pharmaceutical Biotechnology, Division of Sports Medicine and Adult Reconstructive Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, PR China.
| | - Wayne Yuk-Wai Lee
- Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China.
- SH Ho Scoliosis Research Laboratory, Joint Scoliosis Research Center of the Chinese University of Hong Kong and Nanjing University, The Chinese University of Hong Kong, Hong Kong, China.
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12
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Tabata K, Hashimoto M, Takahashi H, Wang Z, Nagaoka N, Hara T, Kamioka H. A morphometric analysis of the osteocyte canaliculus using applied automatic semantic segmentation by machine learning. J Bone Miner Metab 2022; 40:571-580. [PMID: 35338405 DOI: 10.1007/s00774-022-01321-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 02/22/2022] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Osteocytes play a role as mechanosensory cells by sensing flow-induced mechanical stimuli applied on their cell processes. High-resolution imaging of osteocyte processes and the canalicular wall are necessary for the analysis of this mechanosensing mechanism. Focused ion beam-scanning electron microscopy (FIB-SEM) enabled the visualization of the structure at the nanometer scale with thousands of serial-section SEM images. We applied machine learning for the automatic semantic segmentation of osteocyte processes and canalicular wall and performed a morphometric analysis using three-dimensionally reconstructed images. MATERIALS AND METHODS Six-week-old-mice femur were used. Osteocyte processes and canaliculi were observed at a resolution of 2 nm/voxel in a 4 × 4 μm region with 2000 serial-section SEM images. Machine learning was used for automatic semantic segmentation of the osteocyte processes and canaliculi from serial-section SEM images. The results of semantic segmentation were evaluated using the dice similarity coefficient (DSC). The segmented data were reconstructed to create three-dimensional images and a morphological analysis was performed. RESULTS The DSC was > 83%. Using the segmented data, a three-dimensional image of approximately 3.5 μm in length was reconstructed. The morphometric analysis revealed that the median osteocyte process diameter was 73.8 ± 18.0 nm, and the median pericellular fluid space around the osteocyte process was 40.0 ± 17.5 nm. CONCLUSION We used machine learning for the semantic segmentation of osteocyte processes and canalicular wall for the first time, and performed a morphological analysis using three-dimensionally reconstructed images.
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Affiliation(s)
- Kaori Tabata
- Department of Orthodontics, Okayama University Hospital, Okayama, Japan
| | - Mana Hashimoto
- Department of Orthodontics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kita-ku, Okayama, Okayama, 700-8558, Japan
| | - Haruka Takahashi
- Department of Orthodontics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kita-ku, Okayama, Okayama, 700-8558, Japan
| | - Ziyi Wang
- Department of Orthodontics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kita-ku, Okayama, Okayama, 700-8558, Japan
| | - Noriyuki Nagaoka
- Advanced Research Center for Oral and Craniofacial Sciences, Okayama University Dental School, Okayama, Japan
| | - Toru Hara
- Research Center for Structural Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Hiroshi Kamioka
- Department of Orthodontics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata, Kita-ku, Okayama, Okayama, 700-8558, Japan.
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13
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Che YJ, Guo JB, Hao YF, Luo ZP. Regenerating and repairing degenerative intervertebral discs by regulating the micro/nano environment of degenerative bony endplates based on low-tension mechanics. BMC Musculoskelet Disord 2022; 23:462. [PMID: 35578221 PMCID: PMC9112526 DOI: 10.1186/s12891-022-05422-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 05/05/2022] [Indexed: 11/10/2022] Open
Abstract
Background Conservative treatment is the recommended first-line treatment for degenerative disc diseases. Traction therapy has historically been one of the most common clinical methods to address this, but the clinical effect remains controversial. Methods Forty-two six-month-old male Sprague-Dawley rats were randomly divided into six groups: the model group (Group A, four coccyx vertebrae (Co7-Co10) were fixed with customized external fixators, and the vertebral disc degeneration model was constructed by axial compression of the target segment Co8 - Co9 for 4 weeks), the experimental control group (Group B, after successful modeling, the external fixation device was removed and self-rehabilitation was performed) and four intervention groups (Groups C to F): Groups C and E: Co8 - Co9 vertebrae compressed for 4 weeks followed by two or 4 weeks of high tension traction (HTT), respectively, and Groups D and F: vertebrae compressed for 4 weeks followed by two or 4 weeks of low-tension traction (LTT), respectively. Imaging tests (X-ray and MRI) were performed to assess disc height and T2 signal intensity at each time point. After the experiment, the animals were euthanized, and the caudal vertebrae were collected for analysis of intervertebral disc histopathology, proteoglycan content, and micronanostructure of the annulus fibrosus, nucleus pulposus and bony endplate. Results Signs of tissue regeneration were apparent in all four intervention groups. After two to 4 weeks of intervention (HTT and LTT), the morphology of pores in the bony endplate, their number, and diameter had recovered significantly compared with those in Group A. The LTT group was superior to the HTT group, and the 4w in situ group was significantly superior to the 2w group. Meanwhile, the histological scores of discs, the mean fibril diameter and modulus of annulus fibrosus were significantly improved compared with the control groups, and the LTT group was superior to HTT group. Conclusions Low-tension traction better promotes active reconstruction of bony endplates and improves the elastic modulus and micro/nanostructure of the disc. Thus, it further promotes the regeneration and repair of intervertebral discs.
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Affiliation(s)
- Yan-Jun Che
- Orthopedics and Sports Medicine Center, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 215008, Jiangsu Province, China.
| | - Jiang-Bo Guo
- Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, SuZhou, Jiangsu, 215007, People's Republic of China
| | - Yue Feng Hao
- Orthopedics and Sports Medicine Center, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 215008, Jiangsu Province, China
| | - Zong-Ping Luo
- Department of Orthopaedics, Orthopaedic Institute, The First Affiliated Hospital of SooChow University, 708 Renmin Rd, SuZhou, Jiangsu, 215007, People's Republic of China
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14
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Tang T, Landis W, Raguin E, Werner P, Bertinetti L, Dean M, Wagermaier W, Fratzl P. A 3D Network of Nanochannels for Possible Ion and Molecule Transit in Mineralizing Bone and Cartilage. ADVANCED NANOBIOMED RESEARCH 2022. [DOI: 10.1002/anbr.202100162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Tengteng Tang
- Department of Biomaterials Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
| | - William Landis
- Department of Preventive and Restorative Dental Sciences University of California at San Francisco 707 Parnassus Avenue San Francisco CA 94143 USA
| | - Emeline Raguin
- Department of Biomaterials Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
| | - Peter Werner
- Department of Biomaterials Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
| | - Luca Bertinetti
- Center for Molecular Bioengineering TU Dresden Tatzberg 41 01307 Dresden Germany
| | - Mason Dean
- Department of Infectious Diseases and Public Health City University of Hong Kong 31 To Yuen Street, Tat Chee Avenue Kowloon Hong Kong
| | - Wolfgang Wagermaier
- Department of Biomaterials Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
| | - Peter Fratzl
- Department of Biomaterials Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
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15
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Liu HY, Zhao CH, Zhang H, Wang W, Liu QJ. Simulation study on the effect of resistance exercise on the hydrodynamic microenvironment of osteocytes in microgravity. Comput Methods Biomech Biomed Engin 2022; 25:1757-1766. [PMID: 35170387 DOI: 10.1080/10255842.2022.2037130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Osteoporosis occurs in astronauts after long-term space flight owing to the lack of gravity. The mechanical microenvironment of osteocytes in load-bearing bone are changed during resistance exercise, which prevents massive bone loss in the human body. A cylindrical fluid-structure coupling finite element model for osteons with a two-stage pore structure (i.e., Haversian canal, lacunar-canalicular system) was established with the software COMSOL. In the Earth's gravity field and in microgravity, considering the effects of pulsating pressure of arterioles, a comparative study was performed on the changes in hydrodynamic microenvironment of osteocytes during human body high-intensity exercise at different frequencies (defined as causing bone to produce 3000 με) and the body is at rest. Positive and negative liquid pressure (with respect to one atmosphere pressure) alternately acted on osteocytes during human exercising, but only positive pressure acted on osteocytes during human resting. The variation range of liquid pressure acted on osteocytes during human exercising was significantly higher than that during resting. The liquid flow velocity around osteocytes during body exercise was about four orders of magnitude higher than that during resting. In microgravity, moderate physical exercise can obviously improve the hydrodynamic microenvironment of osteocytes in load-bearing bone, which could compensate for the lack of mechanical stimulation to osteocytes caused by the lack of gravity, thereby promoting the normal physiological function of osteocytes. To a certain extent, these results revealed the biomechanical mechanism by which exercise has an effect in fighting osteoporosis in astronauts.
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Affiliation(s)
- Hai-Ying Liu
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, People's Republic of China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology), Tianjin, People's Republic of China
| | - Chao-Hui Zhao
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, People's Republic of China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology), Tianjin, People's Republic of China
| | - Hao Zhang
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, People's Republic of China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology), Tianjin, People's Republic of China
| | - Wei Wang
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin, People's Republic of China
| | - Qing-Jian Liu
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, People's Republic of China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education (Tianjin University of Technology), Tianjin, People's Republic of China
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16
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Goff E, Buccino F, Bregoli C, McKinley JP, Aeppli B, Recker RR, Shane E, Cohen A, Kuhn G, Müller R. Large-scale quantification of human osteocyte lacunar morphological biomarkers as assessed by ultra-high-resolution desktop micro-computed tomography. Bone 2021; 152:116094. [PMID: 34186251 DOI: 10.1016/j.bone.2021.116094] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 06/19/2021] [Accepted: 06/24/2021] [Indexed: 02/07/2023]
Abstract
Ultra-high-resolution imaging of the osteocyte lacuno-canalicular network (LCN) three-dimensionally (3D) in a high-throughput fashion has greatly improved the morphological knowledge about the constituent structures - positioning them as potential biomarkers. Technologies such as serial focused ion beam/scanning electron microscopy (FIB/SEM) and confocal scanning laser microscopy (CLSM) can image in extremely high resolution, yet only capture a small number of lacunae. Synchrotron radiation computed tomography (SR-CT) can image with both high resolution and high throughput but has a limited availability. Desktop micro-computed tomography (micro-CT) provides an attractive balance: high-throughput imaging on the micron level without the restrictions of SR-CT availability. In this study, accuracy, reproducibility, and sensitivity of large-scale quantification of human osteocyte lacunar morphometries were assessed by ultra-high-resolution desktop micro-computed tomography. For this purpose, thirty-one transiliac human bone biopsies containing trabecular and cortical regions were imaged using ultra-high-resolution desktop micro-CT at a nominal isotropic voxel resolution of 1.2 µm. The resulting 3D images were segmented, component labeled, and the following morphometric parameters of 7.71 million lacunae were measured: Lacunar number (Lc.N), density (Lc.N/BV), porosity (Lc.TV/BV), volume (Lc.V), surface area (Lc.S), surface area to volume ratio (Lc.S/Lc.V), stretch (Lc.St), oblateness (Lc.Ob), sphericity (Lc.Sr), equancy (Lc.Eq), and angle (Lc.θ). Accuracy was quantified by comparing automated lacunar identification to manual identification. Mean true positive rate (TPR), false positive rate (FPR), and false negative rate (FNR) were 89.0%, 3.4%, and 11.0%, respectively. Regarding the reproducibility of lacunar morphometry from repeated measurements, precision errors were low (0.2-3.0%) and intraclass correlation coefficients were high (0.960-0.999). Significant differences between cortical and trabecular regions (p<0.001) existed for Lc.N/BV, Lc.TV/BV, local lacunar surface area (<Lc.S>), and local lacunar volume (<Lc.V>), all of which demonstrate the sensitivity of the method and are possible biomarker candidates. This study provides the foundation required for future large-scale morphometric studies using ultra-high-resolution desktop micro-CT and high-throughput analysis of millions of osteocyte lacunae in human bone samples.
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Affiliation(s)
- Elliott Goff
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | | | - Chiara Bregoli
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Jonathan P McKinley
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland; Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA, USA
| | - Basil Aeppli
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Robert R Recker
- Department of Medicine, Creighton University Medical Center, Omaha, NE, USA
| | - Elizabeth Shane
- Department of Medicine, Columbia University Vagelos College of Physicians & Surgeons, New York, NY, USA
| | - Adi Cohen
- Department of Medicine, Columbia University Vagelos College of Physicians & Surgeons, New York, NY, USA
| | - Gisela Kuhn
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Ralph Müller
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland.
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17
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Microscale compressive behavior of hydrated lamellar bone at high strain rates. Acta Biomater 2021; 131:403-414. [PMID: 34245895 DOI: 10.1016/j.actbio.2021.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/30/2021] [Accepted: 07/02/2021] [Indexed: 11/20/2022]
Abstract
The increased risk of fracture in the elderly associated with metabolic conditions like osteoporosis poses a significant strain on health care systems worldwide. Due to bone's hierarchical nature, it is necessary to study its mechanical properties and failure mechanisms at several length scales. We conducted micropillar compression experiments on ovine cortical bone to assess the anisotropic mechanical response at the lamellar scale over a wide range of strain rates (10-4 to 8·102 s-1). At the microscale, lamellar bone exhibits a strain rate sensitivity similar to what is reported at the macroscale suggesting that it is an intrinsic property of the extracellular matrix. Significant shear band thickening was observed at high strain rates by HRSEM and STEM imaging. This is likely caused by the material's inability to accommodate the imposed deformation by propagation of thin kink bands and shear cracks at high strain rates, leading to shear band thickening and nucleation. The post-yield behavior is strain rate and direction dependent: hardening was observed for transverse oriented micropillars and hardening modulus increases with strain rate by a factor of almost 2, while axially oriented micropillars showed strain softening and an increase of the softening peak width and work to ultimate stress as a function of strain rate. This suggests that for compression at the micrometer scale, energy absorption in bone increases with strain rate. This study highlights the importance of investigating bone strength and post-yield behavior at lower length scales, under hydrated conditions and at clinically relevant strain rates. STATEMENT OF SIGNIFICANCE: We performed micropillar compression experiments of ovine cortical bone at two different orientations and over seven orders of magnitude of strain rate. Experiments were performed under humid condition to mimic the natural conditions of bone in a human body using a newly developed micro-indenter setup. The strain rate sensitivity was found to be of a similar magnitude to what has been reported for higher length scales, suggesting that the strain rate sensitivity is an intrinsic property of the bone extracellular matrix. In addition, localized shear deformation in thick bands was observed for the first time at high strain rates, highlighting the importance of investigating bone under conditions representative of an accident or fall at several length scales.
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18
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Scher N, Rechav K, Paul-Gilloteaux P, Avinoam O. In situ fiducial markers for 3D correlative cryo-fluorescence and FIB-SEM imaging. iScience 2021; 24:102714. [PMID: 34258551 PMCID: PMC8253967 DOI: 10.1016/j.isci.2021.102714] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/12/2021] [Accepted: 06/08/2021] [Indexed: 11/26/2022] Open
Abstract
Imaging of cells and tissues has improved significantly over the last decade. Dual-beam instruments with a focused ion beam mounted on a scanning electron microscope (FIB-SEM), offering high-resolution 3D imaging of large volumes and fields-of-view are becoming widely used in the life sciences. FIB-SEM has most recently been implemented on fully hydrated, cryo-immobilized, biological samples. Correlative light and electron microscopy workflows combining fluorescence microscopy (FM) with FIB-SEM imaging exist, whereas workflows combining cryo-FM and cryo-FIB-SEM imaging are not yet commonly available. Here, we demonstrate that fluorescently labeled lipid droplets can serve as in situ fiducial markers for correlating cryo-FM and FIB-SEM datasets and that this approach can be used to target the acquisition of large FIB-SEM stacks spanning tens of microns under cryogenic conditions. We also show that cryo-FIB-SEM imaging is particularly informative for questions related to organelle structure and inter-organellar contacts, nuclear organization, and mineral deposits in cells.
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Affiliation(s)
- Nadav Scher
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Katya Rechav
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel
| | - Perrine Paul-Gilloteaux
- Structure Fédérative de Recherche François Bonamy, INSERM, CNRS, Université de Nantes, Nantes, France
| | - Ori Avinoam
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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19
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Weiner S, Raguin E, Shahar R. High resolution 3D structures of mineralized tissues in health and disease. Nat Rev Endocrinol 2021; 17:307-316. [PMID: 33758360 DOI: 10.1038/s41574-021-00479-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/11/2021] [Indexed: 02/06/2023]
Abstract
A thorough knowledge of the structures of healthy mineralized tissues, such as bone or cartilage, is key to understanding the pathological changes occurring during disease. Such knowledge enables the underlying mechanisms that are responsible for pathology to be pinpointed. One high-resolution 3D method in particular - focused ion beam-scanning electron microscopy (FIB-SEM) - has fundamentally changed our understanding of healthy vertebrate mineralized tissues. FIB-SEM can be used to study demineralized matrix, the hydrated components of tissue (including cells) using cryo-fixation and even untreated mineralized tissue. The latter requires minimal sample preparation, making it possible to study enough samples to carry out studies capable of detecting statistically significant differences - a pre-requisite for the study of pathological tissues. Here, we present an imaging and characterization strategy for tissue structures at different length scales, describe new insights obtained on healthy mineralized tissues using FIB-SEM, and suggest future research directions for both healthy and diseased mineralized tissues.
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Affiliation(s)
- Steve Weiner
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
| | - Emeline Raguin
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Ron Shahar
- Koret School of Veterinary Medicine, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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20
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Zhang H, Liu HY, Zhang CQ, Liu ZZ, Wang W. Simulation of the mechanical behavior of osteons using artificial gravity devices in microgravity. Comput Methods Biomech Biomed Engin 2021; 24:1578-1587. [PMID: 33724105 DOI: 10.1080/10255842.2021.1901086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Aviation medical research shows that disuse osteoporosis will occur after long-term space flight. Even with countermeasures such as exercise and drug treatments, this outcome cannot be avoided in flight. In recent years, the application of artificial gravity devices that change the mechanical microenvironment of bone in microgravity have shown promise in mitigating the risk of disuse osteoporosis. Considering the existence of osteocytes, a fluid-solid coupling finite element model for osteons with two-stage pore structure (Haversian canal, lacunar-canalicular system) was established. In order to study the changes in the mechanical behavior of osteocytes under the action of various artificial gravity (AG) devices, including long-arm centrifuge (LAC), short-arm centrifuge (SAC), and a lower body negative pressure (LBNP) chamber. In addition, the difference in pulsating pressure and static pressure stress caused by the gravity gradient under the AG devices was examined. The simulation results showed that the AG devices could effectively improve the stress level of osteocytes in microgravity. The mechanical microenvironment of osteocytes that was provided by the LAC was closest to that of the Earth's gravitational field. The mechanical stimulation on osteocytes was not significantly improved by the SAC, but from a practical viewpoint, it occupied less space than the LAC. The LBNP chamber created a higher level of stress for osteocytes. Therefore, the LAC was an ideal device for replacing Earth's gravitational field, except for the practical limitations of its physical size. In contrast, the LBNP device had the greatest application potential in training for its expansibility and convenience.
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Affiliation(s)
- Hao Zhang
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, People's Republic of China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, People's Republic of China
| | - Hai-Ying Liu
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, People's Republic of China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, People's Republic of China
| | - Chun-Qiu Zhang
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, People's Republic of China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, People's Republic of China
| | - Zhen-Zhong Liu
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, People's Republic of China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, People's Republic of China
| | - Wei Wang
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin, People's Republic of China
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21
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Akhter MP, Recker RR. High resolution imaging in bone tissue research-review. Bone 2021; 143:115620. [PMID: 32866682 DOI: 10.1016/j.bone.2020.115620] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 12/14/2022]
Abstract
This review article focuses on imaging of bone tissue to understand skeletal health with regards to bone quality. Skeletal fragility fractures are due to bone diseases such as osteoporosis which result in low bone mass and bone mineral density (BMD) leading to high risk of fragility fractures. Recent advances in imaging and analysis technologies have highly benefitted the field of biological sciences. In particular, their application in skeletal health has been of significant importance in understanding bone mechanical behavior (structure and properties) at the tissue level. While synchrotron based microCT technique has remained the gold standard for non-destructive evaluation of structure in material and biological sciences, several lab based microCT systems have been developed to provide high resolution imaging of specimens with greater access, and ease of use in laboratory settings. Lab based microCT scanners are widely used in the bone field as a standard tool to evaluate three-dimensional (3D) morphologies of bone structure at image resolutions appropriate for bone samples from small animals to bone biopsy specimens from humans. Both synchrotron and standard lab based microCT systems provide high resolution imaging ex vivo for a small sized specimen. A few X-ray based systems are also commercially available for in vivo scanning at relatively low image resolutions. Synchrotron-based CT microscopy is being used for various ultra-high-resolution image analyses using complex 3D software. However, the synchrotron-based CT technology is in high demand, allows only limited numbers of specimens, expensive, requires complex additional instrumentation, and is not easily available to researchers as it requires access to a synchrotron source which is always limited. Therefore, desktop laboratory scanners (microXCT, Zeiss/Xradia, Scanco, SkyScan. etc.), mimicking the synchrotron based CT technology or image resolution, have been developed to solve the accessibility issues. These lab based scanners have helped both material science, and the bone field to investigate bone tissue morphologies at submicron mage resolutions. Considerable progress has been made in both in vivo and ex vivo imaging towards providing high resolution images of bone tissue. Both clinical and research imaging technologies will continue to improve and help understand osteoporosis and other related skeletal issues in order to develop targeted treatments for bone fragility. This review summarizes the high resolution imaging work in bone research.
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Affiliation(s)
- M P Akhter
- Creighton University Osteoporosis Research Center, Omaha, NE, United States of America.
| | - R R Recker
- Creighton University Osteoporosis Research Center, Omaha, NE, United States of America
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22
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Okawara H, Arai Y, Matsuno H, Marcián P, Borák L, Aoki K, Wakabayashi N. Effect of load-induced local mechanical strain on peri-implant bone cell activity related to bone resorption and formation in mice: An analysis of histology and strain distributions. J Mech Behav Biomed Mater 2021; 116:104370. [PMID: 33545417 DOI: 10.1016/j.jmbbm.2021.104370] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 02/07/2023]
Abstract
The purpose of this study was to investigate the effect of load-induced local mechanical strain on bone cell activity of peri-implant bone in mice. Titanium implants were placed in the maxillae of 13-week-old male C57BL/6J mice and subjected to intermittent 0.15 N, 0.3 N, or 0.6 N loads for 30 min/day for 6 days. The animals were sacrificed 2 days after the final loading. Unloaded mice were used as controls. An animal-specific three-dimensional finite element model was constructed based on morphological data retrieved from in vivo microfocus computed tomography for each mouse to calculate the mechanical strain distribution. Strain distribution images were overlaid on corresponding histological images of the same site in the same animal. The buccal cervical region of the peri-implant bone was predetermined as the region of interest (ROI). Each ROI was divided by four strain intensity levels: 0-20 με, 20-60 με, 60-100 με, and ≥100 με, and the bone histomorphometric parameters were analyzed by the total area of each strain range for all loaded samples. The distance between the calcified front and calcein labeling as a parameter representing the mineral apposition rate was significantly greater in the areas with strain intensity ≥100 με than in the area with strain intensity <100 με, suggesting that the bone formation activity of osteoblasts was locally enhanced by a higher mechanical strain. However, the shrunken osteocytes and the empty osteocyte lacunae were significantly lower in the highest strain area, suggesting that osteoclastogenesis was more retarded in higher strain areas than in lower strain areas. The histomorphometric parameters were not affected geometrically in the unloaded animals, suggesting that the load-induced mechanical strain caused differences in the histomorphometric parameters. Our findings support the hypothesis that bone cell activity related to bone resorption and formation is local strain-dependent on implant loading.
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Affiliation(s)
- Hisami Okawara
- Removable Partial Prosthodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Yuki Arai
- Removable Partial Prosthodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Hitomi Matsuno
- Removable Partial Prosthodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Petr Marcián
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69, Brno, Czech Republic
| | - Libor Borák
- Institute of Solid Mechanics, Mechatronics and Biomechanics, Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896/2, 616 69, Brno, Czech Republic
| | - Kazuhiro Aoki
- Department of Basic Oral Health Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan
| | - Noriyuki Wakabayashi
- Removable Partial Prosthodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
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23
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Dole NS, Yee CS, Schurman CA, Dallas SL, Alliston T. Assessment of Osteocytes: Techniques for Studying Morphological and Molecular Changes Associated with Perilacunar/Canalicular Remodeling of the Bone Matrix. Methods Mol Biol 2021; 2230:303-323. [PMID: 33197021 PMCID: PMC9165628 DOI: 10.1007/978-1-0716-1028-2_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recent advances have revived interest in the concept of osteocyte perilacunar/canalicular remodeling (PLR) and have motivated efforts to identify the mechanisms regulating this process in bone in the context of normal physiology and pathological conditions. Here, we describe several methods that are evaluating morphological changes associated with PLR function of osteocytes.
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Affiliation(s)
- Neha S Dole
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Cristal S Yee
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Charles A Schurman
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, USA
- UC Berkeley/UCSF Graduate Program in Bioengineering, San Francisco, CA, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO, USA
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, USA.
- UC Berkeley/UCSF Graduate Program in Bioengineering, San Francisco, CA, USA.
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24
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Zelaya-Lainez L, Kariem H, Nischkauer W, Limbeck A, Hellmich C. "Variances" and "in-variances" in hierarchical porosity and composition, across femoral tissues from cow, horse, ostrich, emu, pig, rabbit, and frog. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 117:111234. [PMID: 32919621 DOI: 10.1016/j.msec.2020.111234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/10/2020] [Accepted: 06/21/2020] [Indexed: 10/24/2022]
Abstract
It is very well known that bone is a hierarchically organized material produced by bone cells residing in the fluid environments filling (larger) vascular pores and (smaller) lacunar pores. The extracellular space consists of hydroxyapatite crystals, collagen type I molecules, and water with non-collageneous organics. It is less known to which extent the associated quantities (mineral, organic, and water concentrations; vascular, lacunar, and extracellular porosities) vary across species, organs, and ages. We here investigate the aforementioned quantities across femoral shaft tissues from cow, horse, emu, frog, ostrich, pig, and rabbit; by means of light microscopy and dehydration-demineralization tests; thereby revealing interesting invariances: The extracellular volume fractions of organic matter turn out to be similar across all tested non-amphibian tissues; as do the extracellular volume fractions of hydroxyapatite across all tested mammals. Hence, the chemical composition of the femoral extracellular bone matrix is remarkably "invariant" across differently aged mammals; while the water content shows significant variations, as does the partitions of water between the different pore spaces. The latter exhibit strikingly varying morphologies as well. This finding adds to the ample "universal patterns" in the sense of evolutionary developmental biology; and it provides interesting design requirements for the development of novel biomimetic tissue engineering solutions.
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Affiliation(s)
- Luis Zelaya-Lainez
- Institute for Mechanics of Materials and Structures, TU Wien - Vienna University of Technology, Karlsplatz 13/E202, 1040 Vienna, Austria
| | - Hawraa Kariem
- Institute for Mechanics of Materials and Structures, TU Wien - Vienna University of Technology, Karlsplatz 13/E202, 1040 Vienna, Austria
| | - Winfried Nischkauer
- Institute of Chemical Technologies and Analytics, Division of Instrumental Analytical Chemistry, TU Wien - Vienna University of Technology, Getreidemarkt 9/164, 1060 Vienna, Austria
| | - Andreas Limbeck
- Institute of Chemical Technologies and Analytics, Division of Instrumental Analytical Chemistry, TU Wien - Vienna University of Technology, Getreidemarkt 9/164, 1060 Vienna, Austria
| | - Christian Hellmich
- Institute for Mechanics of Materials and Structures, TU Wien - Vienna University of Technology, Karlsplatz 13/E202, 1040 Vienna, Austria.
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25
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Milovanovic P, Busse B. Phenomenon of osteocyte lacunar mineralization: indicator of former osteocyte death and a novel marker of impaired bone quality? Endocr Connect 2020; 9:R70-R80. [PMID: 32168472 PMCID: PMC7159263 DOI: 10.1530/ec-19-0531] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 03/13/2020] [Indexed: 11/09/2022]
Abstract
An increasing number of patients worldwide suffer from bone fractures that occur after low intensity trauma. Such fragility fractures are usually associated with advanced age and osteoporosis but also with long-term immobilization, corticosteroid therapy, diabetes mellitus, and other endocrine disorders. It is important to understand the skeletal origins of increased bone fragility in these conditions for preventive and therapeutic strategies to combat one of the most common health problems of the aged population. This review summarizes current knowledge pertaining to the phenomenon of micropetrosis (osteocyte lacunar mineralization). As an indicator of former osteocyte death, micropetrosis is more common in aged bone and osteoporotic bone. Considering that the number of mineralized osteocyte lacunae per bone area can distinguish healthy, untreated osteoporotic and bisphosphonate-treated osteoporotic patients, it could be regarded as a novel structural marker of impaired bone quality. Further research is needed to clarify the mechanism of lacunar mineralization and to explore whether it could be an additional target for preventing or treating bone fragility related to aging and various endocrine diseases.
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Affiliation(s)
- Petar Milovanovic
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Laboratory for Anthropology and Skeletal Biology, Institute of Anatomy, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Björn Busse
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Correspondence should be addressed to B Busse:
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26
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Davesne D, Schmitt AD, Fernandez V, Benson RBJ, Sanchez S. Three-dimensional characterization of osteocyte volumes at multiple scales, and its relationship with bone biology and genome evolution in ray-finned fishes. J Evol Biol 2020; 33:808-830. [PMID: 32144878 DOI: 10.1111/jeb.13612] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 02/11/2020] [Accepted: 02/21/2020] [Indexed: 12/16/2022]
Abstract
Osteocytes, cells embedded within the bone mineral matrix, inform on key aspects of vertebrate biology. In particular, a relationship between volumes of the osteocytes and bone growth and/or genome size has been proposed for several tetrapod lineages. However, the variation in osteocyte volume across different scales is poorly characterized and mostly relies on incomplete, two-dimensional information. In this study, we characterize the variation of osteocyte volumes in ray-finned fishes (Actinopterygii), a clade including more than half of modern vertebrate species in which osteocyte biology is poorly known. We use X-ray synchrotron micro-computed tomography (SRµCT) to achieve a three-dimensional visualization of osteocyte lacunae and direct measurement of their size (volumes). Our specimen sample is designed to characterize variation in osteocyte lacuna morphology at three scales: within a bone, among the bones of one individual and among species. At the intra-bone scale, we find that osteocyte lacunae vary noticeably in size between zones of organized and woven bone (being up to six times larger in woven bone), and across cyclical bone deposition. This is probably explained by differences in bone deposition rate, with larger osteocyte lacunae contained in bone that deposits faster. Osteocyte lacuna volumes vary 3.5-fold among the bones of an individual, and this cannot readily be explained by variation in bone growth rate or other currently observable factors. Finally, we find that genome size provides the best explanation of variation in osteocyte lacuna volume among species: actinopterygian taxa with larger genomes (polyploid taxa in particular) have larger osteocyte lacunae (with a ninefold variation in median osteocyte volume being measured). Our findings corroborate previous two-dimensional studies in tetrapods that also observed similar patterns of intra-individual variation and found a correlation with genome size. This opens new perspectives for further studies on bone evolution, physiology and palaeogenomics in actinopterygians, and vertebrates as a whole.
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Affiliation(s)
- Donald Davesne
- Department of Earth Sciences, University of Oxford, Oxford, UK
| | - Armin D Schmitt
- Department of Earth Sciences, University of Oxford, Oxford, UK
| | - Vincent Fernandez
- European Synchrotron Radiation Facility, Grenoble, France.,Imaging and Analysis Centre, Natural History Museum, London, UK
| | | | - Sophie Sanchez
- European Synchrotron Radiation Facility, Grenoble, France.,Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala University, Uppsala, Sweden
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27
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Assessment of the human bone lacuno-canalicular network at the nanoscale and impact of spatial resolution. Sci Rep 2020; 10:4567. [PMID: 32165649 PMCID: PMC7067834 DOI: 10.1038/s41598-020-61269-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 02/17/2020] [Indexed: 11/09/2022] Open
Abstract
Recently, increasing attention has been given to the study of osteocytes, the cells that are thought to play an important role in bone remodeling and in the mechanisms of bone fragility. The interconnected osteocyte system is deeply embedded inside the mineralized bone matrix and lies within a closely fitted porosity known as the lacuno-canalicular network. However, quantitative data on human samples remain scarce, mostly measured in 2D, and there are gaps to be filled in terms of spatial resolution. In this work, we present data on femoral samples from female donors imaged with isotropic 3D spatial resolution by magnified X-ray phase nano computerized-tomography. We report quantitative results on the 3D structure of canaliculi in human femoral bone imaged with a voxel size of 30 nm. We found that the lacuno-canalicular porosity occupies on average 1.45% of the total tissue volume, the ratio of the canalicular versus lacunar porosity is about 37.7%, and the primary number of canaliculi stemming from each lacuna is 79 on average. The examination of this number at different distances from the surface of the lacunae demonstrates branching in the canaliculi network. We analyzed the impact of spatial resolution on quantification by comparing parameters extracted from the same samples imaged with 120 nm and 30 nm voxel sizes. To avoid any bias related to the analysis region, the volumes at 120 nm and 30 nm were registered and cropped to the same field of view. Our results show that the measurements at 120 and 30 nm are strongly correlated in our data set but that the highest spatial resolution provides more accurate information on the canaliculi network and its branching properties.
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28
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Alsassa S, Lefèvre T, Laugier V, Stindel E, Ansart S. Modeling Early Stages of Bone and Joint Infections Dynamics in Humans: A Multi-Agent, Multi-System Based Model. Front Mol Biosci 2020; 7:26. [PMID: 32226790 PMCID: PMC7080862 DOI: 10.3389/fmolb.2020.00026] [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: 11/10/2018] [Accepted: 02/07/2020] [Indexed: 11/13/2022] Open
Abstract
Diagnosis and management of bone and joint infections (BJI) is a challenging task. The high intra and inter patient's variability in terms of clinical presentation makes it impossible to rely on a systematic description or classical statistical analysis for its diagnosis. Advances can be achieved through a better understanding of the system behavior that results from the interactions between the components at a micro-scale level, which is difficult to mastered using traditional methods. Multiple studies from the literature report factors and interactions that affect the dynamics of the BJI system. The objectives of this study were (i) to perform a systematic review to identify relevant interactions between agents (cells, pathogens) and parameters values that characterize agents and interactions, and (ii) to develop a two dimensional computational model of the BJI system based on the results of the systematic review. The model would simulate the behavior resulting from the interactions on the cellular and molecular levels to explore the BJI dynamics, using an agent-based modeling approach. The BJI system's response to different microbial inoculum levels was simulated. The model succeeded in mimicking the dynamics of bacteria, the innate immune cells, and the bone mass during the first stage of infection and for different inoculum levels in a consistent manner. The simulation displayed the destruction in bone tissue as a result of the alteration in bone remodeling process during the infection. The model was used to generate different patterns of system behaviors that could be analyzed in further steps. Simulations results suggested evidence for the existence of latent infections. Finally, we presented a way to analyze and synthesize massive simulated data in a concise and comprehensive manner based on the semi-supervised identification of ordinary differential equations (ODE) systems. It allows to use the known framework for temporal and structural ODE analyses and therefore summarize the whole simulated system dynamical behavior. This first model is intended to be validated by in vivo or in vitro data and expected to generate hypotheses to be challenged by real data. Step by step, it can be modified and complexified based on the test/validation iteration cycles.
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Affiliation(s)
- Salma Alsassa
- Laboratory of Medical Information Processing (LaTIM - UMR 1101 INSERM), IBRS, Université de Bretagne Occidentale, Department of Medicine, Brest, France
- Tekliko SARL, Paris, France
| | - Thomas Lefèvre
- Iris UMR 8156 CNRS - U997 Inserm - EHESS - UP 13, Paris, France
- AP-HP, Jean Verdier Teaching Hospital, Department of Legal and Social Medicine, Bondy, France
| | | | - Eric Stindel
- Laboratory of Medical Information Processing (LaTIM - UMR 1101 INSERM), IBRS, Université de Bretagne Occidentale, Department of Medicine, Brest, France
- La Cavale Blanche University Hospital, Infection Diseases Unit, Brest, France
| | - Séverine Ansart
- Laboratory of Medical Information Processing (LaTIM - UMR 1101 INSERM), IBRS, Université de Bretagne Occidentale, Department of Medicine, Brest, France
- La Cavale Blanche University Hospital, Infection Diseases Unit, Brest, France
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29
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Choy MHV, Wong RMY, Li MC, Wang BY, Liu XD, Lee W, Cheng JCY, Chow SKH, Cheung WH. Can we enhance osteoporotic metaphyseal fracture healing through enhancing ultrastructural and functional changes of osteocytes in cortical bone with low-magnitude high-frequency vibration? FASEB J 2020; 34:4234-4252. [PMID: 31961009 DOI: 10.1096/fj.201901595r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 12/31/2019] [Accepted: 01/07/2020] [Indexed: 01/04/2023]
Abstract
Fragility fractures are related to the loss of bone integrity and deteriorated morphology of osteocytes. Our previous studies have reported that low-magnitude high-frequency vibration (LMHFV) promoted osteoporotic fracture healing. As osteocytes are known for mechanosensing and initiating bone repair, we hypothesized that LMHFV could enhance osteoporotic fracture healing through enhancing morphological changes in the osteocyte lacuna-canalicular network (LCN) and mineralization. A metaphyseal fracture model was established in female Sprague-Dawley rats to investigate changes in osteocytes and healing outcomes from early to late phase post-fracture. Our results showed that the LCN exhibited an exuberant outgrowth of canaliculi in the osteoporotic fractured bone at day 14 after LMHFV. LMHFV upregulated the E11, dentin matrix protein 1 (DMP1), and fibroblast growth factor 23 (FGF23), but downregulated sclerostin (Sost) in osteocytes. Moreover, LMHFV promoted mineralization with significant enhancements of Ca/P ratio, mineral apposition rate (MAR), mineralizing surface (MS/BS), and bone mineral density (BMD) in the osteoporotic group. Consistently, better healing was confirmed by microarchitecture and mechanical properties, whereas the enhancement in osteoporotic group was comparable or even greater than the normal group. This is the first report to reveal the enhancement effect of LMHFV on the osteocytes' morphology and functions in osteoporotic fracture healing.
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Affiliation(s)
- Man-Huen Victoria Choy
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Ronald Man-Yeung Wong
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Meng-Chen Li
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Bai Yan Wang
- School of Biomedical Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Xiao Dong Liu
- Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Wayne Lee
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jack Chun-Yiu Cheng
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.,The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
| | - Simon Kwoon-Ho Chow
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.,The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
| | - Wing-Hoi Cheung
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, China.,The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, PR China
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30
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Creecy A, Damrath JG, Wallace JM. Control of Bone Matrix Properties by Osteocytes. Front Endocrinol (Lausanne) 2020; 11:578477. [PMID: 33537002 PMCID: PMC7848033 DOI: 10.3389/fendo.2020.578477] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 12/01/2020] [Indexed: 12/13/2022] Open
Abstract
Osteocytes make up 90-95% of the cellular content of bone and form a rich dendritic network with a vastly greater surface area than either osteoblasts or osteoclasts. Osteocytes are well positioned to play a role in bone homeostasis by interacting directly with the matrix; however, the ability for these cells to modify bone matrix remains incompletely understood. With techniques for examining the nano- and microstructure of bone matrix components including hydroxyapatite and type I collagen becoming more widespread, there is great potential to uncover novel roles for the osteocyte in maintaining bone quality. In this review, we begin with an overview of osteocyte biology and the lacunar-canalicular system. Next, we describe recent findings from in vitro models of osteocytes, focusing on the transitions in cellular phenotype as they mature. Finally, we describe historical and current research on matrix alteration by osteocytes in vivo, focusing on the exciting potential for osteocytes to directly form, degrade, and modify the mineral and collagen in their surrounding matrix.
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Affiliation(s)
- Amy Creecy
- Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, Indianapolis, IN, United States
| | - John G. Damrath
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Joseph M. Wallace
- Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, Indianapolis, IN, United States
- *Correspondence: Joseph M. Wallace,
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31
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Wittig NK, Birkbak ME, Bach-Gansmo FL, Pacureanu A, Wendelboe MH, Brüel A, Thomsen JS, Birkedal H. No Signature of Osteocytic Osteolysis in Cortical Bone from Lactating NMRI Mice. Calcif Tissue Int 2019; 105:308-315. [PMID: 31147741 DOI: 10.1007/s00223-019-00569-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 05/25/2019] [Indexed: 01/13/2023]
Abstract
The roles of osteocytes in bone homeostasis have garnered increasing attention since it has been realized that osteocytes communicate with other organs. It has long been debated whether and/or to which degree osteocytes can break down the bone matrix surrounding them in a process called osteocytic osteolysis. Osteocytic osteolysis has been indicated to be induced by a number of skeletal challenges including lactation in CD1 and C57BL/6 mice, whereas immobilization-induced osteocytic osteolysis is still a matter of controversy. Motivated by the wish to understand this process better, we studied osteocyte lacunae in lactating NMRI mice, which is a widely used outbred mouse strain. Surprisingly, no trace of osteocytic osteolysis could be detected in tibial or femoral cortical bone either by 3D investigation by synchrotron nanotomography, by studies of lacunar cross-sectional areas using scanning electron microscopy, or by light microscopy. These results lead us to conclude that osteocytic osteolysis does not occur in NMRI mice as a response to lactation, in turn suggesting that osteocytic osteolysis may not play a generic role in mobilizing calcium during lactation.
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Affiliation(s)
- Nina Kølln Wittig
- Department of Chemistry and iNANO, Aarhus University, Gustav Wieds vej 14, 8000, Aarhus C, Denmark
| | - Mie Elholm Birkbak
- Department of Chemistry and iNANO, Aarhus University, Gustav Wieds vej 14, 8000, Aarhus C, Denmark
| | - Fiona Linnea Bach-Gansmo
- Department of Chemistry and iNANO, Aarhus University, Gustav Wieds vej 14, 8000, Aarhus C, Denmark
| | - Alexandra Pacureanu
- European Synchrotron Radiation Facility, 71, Avenue des Martyrs, CS 40220, 38043, Grenoble Cedex 9, France
| | - Mette Høegh Wendelboe
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, 8000, Aarhus C, Denmark
| | - Annemarie Brüel
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, 8000, Aarhus C, Denmark
| | - Jesper Skovhus Thomsen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, 8000, Aarhus C, Denmark
| | - Henrik Birkedal
- Department of Chemistry and iNANO, Aarhus University, Gustav Wieds vej 14, 8000, Aarhus C, Denmark.
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32
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Abstract
PURPOSE OF REVIEW Osteocytes are the most abundant bone cells. They are completely encased in mineralized tissue, sitting inside lacunae that are connected by a multitude of canaliculi. In recent years, the osteocyte network has been shown to fulfill endocrine functions and to communicate with a number of other organs. This review addresses emerging knowledge on the connectome of the lacunocanalicular network in different types of bone tissue. RECENT FINDINGS Recent advances in three-dimensional imaging technology started to reveal parameters that are well known from general theory to characterize the function of networks, such as network density, degree of nodes, or shortest path length through the network. The connectome of the lacunocanalicular network differs in some aspects between lamellar and woven bone and seems to change with age. More research is needed to relate network structure to function, such as intercellular transport or communication and its role in mechanosensation, as well as to understand the effect of diseases.
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Affiliation(s)
- Richard Weinkamer
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14424, Potsdam, Germany
| | - Philip Kollmannsberger
- Center for Computational and Theoretical Biology, Universität Würzburg, Campus Hubland Nord 32, 97074, Würzburg, Germany
| | - Peter Fratzl
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14424, Potsdam, Germany.
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Wittig NK, Laugesen M, Birkbak ME, Bach-Gansmo FL, Pacureanu A, Bruns S, Wendelboe MH, Brüel A, Sørensen HO, Thomsen JS, Birkedal H. Canalicular Junctions in the Osteocyte Lacuno-Canalicular Network of Cortical Bone. ACS NANO 2019; 13:6421-6430. [PMID: 31095362 DOI: 10.1021/acsnano.8b08478] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The osteocyte lacuno-canalicular network (LCN) is essential for bone remodeling because osteocytes regulate cell recruitment. This has been proposed to occur through liquid-flow-induced shear forces in the canaliculi. Models of the LCN have thus far assumed that it contains canaliculi connecting the osteocyte lacunae. However, here, we reveal that enlarged spaces occur at places where several canaliculi cross; we name these spaces canalicular junctions. We characterize them in detail within mice cortical bone using synchrotron nanotomography at two length scales, with 50 and 130 nm voxel size, and show that canalicular junctions occur at a density similar to that of osteocyte lacunae and that canalicular junctions tend to cluster. Through confocal laser scanning microscopy, we show that canalicular junctions are widespread as we have observed them in cortical bone from several species, even though the number density of the canalicular junctions was not universal. Fluid flow simulations of a simple model system with and without a canalicular junction clearly show that liquid mass transport and flow velocities are altered by the presence of canalicular junctions. We suggest that these canalicular junctions may play an important role in osteocyte communication and possibly also in canalicular fluid flow. Therefore, we believe that they constitute an important component in the bone osteocyte network.
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Affiliation(s)
| | | | | | | | | | - Stefan Bruns
- Department of Chemistry, University of Copenhagen , 2100 Copenhagen Ø , Denmark
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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] [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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Zhang D, Miranda M, Li X, Han J, Sun Y, Rojas N, He S, Hu M, Lin L, Li X, Ke HZ, Qin YX. Retention of osteocytic micromorphology by sclerostin antibody in a concurrent ovariectomy and functional disuse model. Ann N Y Acad Sci 2019; 1442:91-103. [PMID: 30644553 PMCID: PMC6465143 DOI: 10.1111/nyas.13991] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 09/20/2018] [Accepted: 10/26/2018] [Indexed: 12/26/2022]
Abstract
Prolonged mechanical unloading in bedridden patients and concurrent hormonal dysregulation represents the cause of one of the severest forms of osteoporosis, a condition for which there are very few efficacious interventions available to date. Sclerostin, a Wnt antagonist, acts as a negative regulator of bone formation. Sclerostin antibody (Scl-Ab)-mediated blockade of sclerostin can dramatically enhance bone formation and reduce bone resorption. This study was designed to investigate the therapeutic effect of the Scl-Ab on severe bone loss induced by concurrent mechanical unloading and estrogen deficiency in a hindlimb-suspended and ovariectomized rat model, and to study the cellular mechanisms underlying severe osteoporosis and Scl-Ab action. Unloading and ovariectomy resulted in severe loss of trabecular and cortical bone mass and strength; Scl-Ab can significantly counteract the deterioration of bone in unloaded and/or ovariectomized rats, with noticeably increased cortical bone formation. Scanning electron microscopy analysis revealed that unloading and ovariectomy lead to multiple morphological and structural abnormalities of osteocytes in cortical bone and the abnormalities were abolished by Scl-Ab administration. This study extends our previous conclusion that Scl-Ab represents a promising therapeutic approach for severe bone loss that occurs after being exposed to estrogen deficiency and prolonged mechanical unloading.
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Affiliation(s)
- Dongye Zhang
- Dept. of Biomedical Engineering, Stony Brook University, Stony Brook, NY
| | - Marianna Miranda
- Dept. of Biomedical Engineering, Stony Brook University, Stony Brook, NY
| | - Xiaofei Li
- Dept. of Biomedical Engineering, Stony Brook University, Stony Brook, NY
| | - Jiangmeng Han
- Dept. of Biomedical Engineering, Stony Brook University, Stony Brook, NY
| | - Yueli Sun
- Dept. of Biomedical Engineering, Stony Brook University, Stony Brook, NY
| | - Nancy Rojas
- Dept. of Biomedical Engineering, Stony Brook University, Stony Brook, NY
| | - Shan He
- Dept. of Material Science Engineering, Stony Brook University, Stony Brook, NY
| | - Minyi Hu
- Dept. of Biomedical Engineering, Stony Brook University, Stony Brook, NY
| | - Liangjun Lin
- Dept. of Biomedical Engineering, Stony Brook University, Stony Brook, NY
| | - Xiaodong Li
- Dept. of Metabolic Disorders, Amgen, Inc., Thousand Oaks, CA
| | | | - Yi-Xian Qin
- Dept. of Biomedical Engineering, Stony Brook University, Stony Brook, NY
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Albers J, Pacilé S, Markus MA, Wiart M, Vande Velde G, Tromba G, Dullin C. X-ray-Based 3D Virtual Histology-Adding the Next Dimension to Histological Analysis. Mol Imaging Biol 2019; 20:732-741. [PMID: 29968183 DOI: 10.1007/s11307-018-1246-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Histology and immunohistochemistry of thin tissue sections have been the standard diagnostic procedure in many diseases for decades. This method is highly specific for particular tissue regions or cells, but mechanical sectioning of the specimens is required, which destroys the sample in the process and can lead to non-uniform tissue deformations. In addition, regions of interest cannot be located beforehand and the analysis is intrinsically two-dimensional. Micro X-ray computed tomography (μCT) on the other hand can provide 3D images at high resolution and allows for quantification of tissue structures, as well as the localization of small regions of interest. These advantages advocate the use of μCT for virtual histology tool with or without subsequent classical histology. This review summarizes the most recent examples of virtual histology and provides currently known possibilities of improving contrast and resolution of μCT. Following a background in μCT imaging, ex vivo staining procedures for contrast enhancement are presented as well as label-free virtual histology approaches and the technologies, which could rapidly advance it, such as phase-contrast CT. Novel approaches such as zoom tomography and nanoparticulate contrast agents will also be considered. The current evidence suggests that virtual histology may present a valuable addition to the workflow of histological analysis, potentially reducing the workload in pathology, refining tissue classification, and supporting the detection of small malignancies.
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Affiliation(s)
- J Albers
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany
| | - S Pacilé
- Department of Engineering and Architecture, University of Trieste, Trieste, Italy.,Elettra Sincrotrone Trieste, Trieste, Italy
| | - M A Markus
- Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - M Wiart
- Univ Lyon, CarMeN Laboratory, INSERM, INRA, INSA Lyon, Université Claude Bernard Lyon 1, 69500, Bron, France
| | - G Vande Velde
- Department of Imaging and Pathology, Faculty of Medicine, KU Leuven-University of Leuven, Leuven, Belgium
| | - G Tromba
- Elettra Sincrotrone Trieste, Trieste, Italy
| | - C Dullin
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Göttingen, Germany. .,Elettra Sincrotrone Trieste, Trieste, Italy. .,Translational Molecular Imaging, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany.
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Genthial R, Gerbaix M, Farlay D, Vico L, Beaurepaire E, Débarre D, Gourrier A. Third harmonic generation imaging and analysis of the effect of low gravity on the lacuno-canalicular network of mouse bone. PLoS One 2019; 14:e0209079. [PMID: 30601851 PMCID: PMC6314573 DOI: 10.1371/journal.pone.0209079] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 11/29/2018] [Indexed: 01/07/2023] Open
Abstract
The lacuno-canalicular network (LCN) hosting the osteocytes in bone tissue represents a biological signature of the mechanotransduction activity in response to external biomechanical loading. Using third-harmonic generation (THG) microscopy with sub-micrometer resolution, we investigate the impact of microgravity on the 3D LCN structure in mice following space flight. A specific analytical procedure to extract the LCN characteristics from THG images is described for ex vivo studies of bone sections. The analysis conducted in different anatomical quadrants of femoral cortical bone didn’t reveal any statistical differences between the control, habitat control and flight groups, suggesting that the LCN connectivity is not affected by one month space flight. However, significant variations are systematically observed within each sample. We show that our current lack of understanding of the extent of the LCN heterogeneity at the organ level hinders the interpretation of such investigations based on a limited number of samples and we discuss the implications for future biomedical studies.
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Affiliation(s)
| | - Maude Gerbaix
- INSERM U1059, Université de Lyon, St Etienne, France
- French National Centre for Space Studies, Paris, France
| | | | - Laurence Vico
- INSERM U1059, Université de Lyon, St Etienne, France
| | - Emmanuel Beaurepaire
- Lab. for Optics and Biosciences, Ecole Polytechnique, CNRS, INSERM, Palaiseau, France
| | - Delphine Débarre
- Univ. Grenoble Alpes, CNRS, LIPhy, Grenoble, France
- * E-mail: (DD); (AG)
| | - Aurélien Gourrier
- Univ. Grenoble Alpes, CNRS, LIPhy, Grenoble, France
- * E-mail: (DD); (AG)
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Perrin E, Bou-Saïd B, Massi F. Numerical modeling of bone as a multiscale poroelastic material by the homogenization technique. J Mech Behav Biomed Mater 2018; 91:373-382. [PMID: 30660050 DOI: 10.1016/j.jmbbm.2018.12.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 12/14/2018] [Accepted: 12/14/2018] [Indexed: 11/29/2022]
Abstract
Bone is a complex material showing a hierarchical and porous structure but also a natural ability to remodel thanks to cells sensitive to fluid flows. Based on these characteristics, a multiscale numerical model has been developed in order to represent the bone response under mechanical solicitation. It relies on the homogenization technique, simulating bone as a homogeneous structure having a porous microstructure saturated with bone fluid. The numerical modeling of the loading of a finite volume of bone enables the determination of an equivalent poroelastic stiffness. Focusing on two extreme fluid boundary conditions, the study of the corresponding structural response provides an overview of the fluid contribution to the poroelastic behavior, impacting the stiffness of the considered material. This parameter is either reduced (when the fluid can flow out of the structure) or increased (when the fluid is kept inside the structure) and quantified through this model. The presented poroelastic numerical model is here developed in the perspective of providing a bio-reliable model of bones, to determine the critical parameters that might impact bone remodeling.
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Affiliation(s)
- Eléonore Perrin
- LaMCoS, INSA Lyon, CNRS, UMR5259, University of Lyon, Villeurbanne, France; DIMA, University of Rome, La Sapienza, Rome, Italy.
| | - Benyebka Bou-Saïd
- LaMCoS, INSA Lyon, CNRS, UMR5259, University of Lyon, Villeurbanne, France
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Ayoub S, Tsai KC, Khalighi AH, Sacks MS. The Three-Dimensional Microenvironment of the Mitral Valve: Insights into the Effects of Physiological Loads. Cell Mol Bioeng 2018; 11:291-306. [PMID: 31719888 PMCID: PMC6816749 DOI: 10.1007/s12195-018-0529-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 05/14/2018] [Indexed: 10/24/2022] Open
Abstract
INTRODUCTION In the mitral valve (MV), numerous pathological factors, especially those resulting from changes in external loading, have been shown to affect MV structure and composition. Such changes are driven by the MV interstitial cell (MVIC) population via protein synthesis and enzymatic degradation of extracellular matrix (ECM) components. METHODS While cell phenotype, ECM composition and regulation, and tissue level changes in MVIC shape under stress have been studied, a detailed understanding of the three-dimensional (3D) microstructural mechanisms are lacking. As a first step in addressing this challenge, we applied focused ion beam scanning electron microscopy (FIB-SEM) to reveal novel details of the MV microenvironment in 3D. RESULTS We demonstrated that collagen is organized into large fibers consisting of an average of 605 ± 113 fibrils, with a mean diameter of 61.2 ± 9.8 nm. In contrast, elastin was organized into two distinct structural subtypes: (1) sheet-like lamellar elastin, and (2) circumferentially oriented elastin struts, based on both the aspect ratio and transmural tilt. MVICs were observed to have a large cytoplasmic volume, as evidenced by the large mean surface area to volume ratio 3.68 ± 0.35, which increased under physiological loading conditions to 4.98 ± 1.17. CONCLUSIONS Our findings suggest that each MVIC mechanically interacted only with the nearest 3-4 collagen fibers. This key observation suggests that in developing multiscale MV models, each MVIC can be considered a mechanically integral part of the local fiber ensemble and is unlikely to be influenced by more distant structures.
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Affiliation(s)
- Salma Ayoub
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, POB 5.236, 1 University Station C0200, Austin, TX 78712 USA
| | - Karen C. Tsai
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, POB 5.236, 1 University Station C0200, Austin, TX 78712 USA
| | - Amir H. Khalighi
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, POB 5.236, 1 University Station C0200, Austin, TX 78712 USA
| | - Michael S. Sacks
- Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences and the Department of Biomedical Engineering, The University of Texas at Austin, 201 East 24th Street, POB 5.236, 1 University Station C0200, Austin, TX 78712 USA
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Ciani A, Toumi H, Pallu S, Tsai EHR, Diaz A, Guizar-Sicairos M, Holler M, Lespessailles E, Kewish CM. Ptychographic X-ray CT characterization of the osteocyte lacuno-canalicular network in a male rat's glucocorticoid induced osteoporosis model. Bone Rep 2018; 9:122-131. [PMID: 30246062 PMCID: PMC6146379 DOI: 10.1016/j.bonr.2018.07.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/27/2018] [Indexed: 01/15/2023] Open
Abstract
Ptychographic X-ray computed tomography (PXCT) is a quantitative imaging modality that non-destructively maps the 3D electron density inside an object with tens of nanometers spatial resolution. This method provides unique access to the morphology and structure of the osteocyte lacuno-canalicular network (LCN) and nanoscale density of the tissue in the vicinity of an osteocyte lacuna. Herein, we applied PXCT to characterize the lacunae and LCN in a male Wistar rat model of glucocorticoid-induced osteoporosis (GIO). The ptychographic images revealed significant (p < 0.05) differences in the number of canaliculi originating from the lacuna per ellipsoidal surface unit, Ca.Nb (p = 0.0106), and the 3D morphology of the lacuna (p = 0.0064), between GIO and SHAM groups. Moreover, the mean canalicular diameter, Ca.Dm, was slightly statistically un-significantly smaller in GIO (152 ± 6.5) nm than in SHAM group (165 ± 8) nm (p = 0.053). Our findings indicate that PXCT can non-destructively provide detailed, nanoscale information on the 3D organization of the LCN in correlative studies of pathologies, such as osteoporosis, leading to improved diagnosis and therapy.
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Affiliation(s)
- Antonia Ciani
- Synchrotron Soleil, L'Orme des Merisiers, 91192 Gif-sur-Yvette, France.,EA4708, Imagerie Multimodale, Multiéchelles et Modélisation du Tissu Osseux et Articulaire (I3MTO), Université d'Orléans, 45000 Orléans, France
| | - Hechmi Toumi
- EA4708, Imagerie Multimodale, Multiéchelles et Modélisation du Tissu Osseux et Articulaire (I3MTO), Université d'Orléans, 45000 Orléans, France.,Département Rhumatologie, Centre Hospitalier Régional d'Orléans, 45067 Orléans, France
| | - Stéphane Pallu
- EA4708, Imagerie Multimodale, Multiéchelles et Modélisation du Tissu Osseux et Articulaire (I3MTO), Université d'Orléans, 45000 Orléans, France
| | | | - Ana Diaz
- Paul Scherrer Institut, 5232 Villigen, Switzerland
| | | | - Mirko Holler
- Paul Scherrer Institut, 5232 Villigen, Switzerland
| | - Eric Lespessailles
- EA4708, Imagerie Multimodale, Multiéchelles et Modélisation du Tissu Osseux et Articulaire (I3MTO), Université d'Orléans, 45000 Orléans, France.,Département Rhumatologie, Centre Hospitalier Régional d'Orléans, 45067 Orléans, France
| | - Cameron M Kewish
- Synchrotron Soleil, L'Orme des Merisiers, 91192 Gif-sur-Yvette, France
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Open questions on the 3D structures of collagen containing vertebrate mineralized tissues: A perspective. J Struct Biol 2018; 201:187-198. [DOI: 10.1016/j.jsb.2017.11.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/19/2017] [Accepted: 11/20/2017] [Indexed: 12/29/2022]
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Effect of osteoporosis treatment agents on the cortical bone osteocyte microenvironment in adult estrogen-deficient, osteopenic rats. Bone Rep 2018; 8:115-124. [PMID: 29955630 PMCID: PMC6020081 DOI: 10.1016/j.bonr.2018.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 01/18/2018] [Accepted: 02/23/2018] [Indexed: 11/21/2022] Open
Abstract
Though osteoporosis is a significant cause of disability worldwide, treatment with pharmacologic agents decreases risk of fragility fracture. Though these treatments act through the bone remodeling system to improve bone mass, it is unclear if they alter the response of bone to mechanical loading at the level of the osteocyte. This pre-clinical study determined the relationship between microstructural bone tissue properties and osteocyte lacunar size and density to strain around osteocytes with standard osteoporosis treatment or sequential therapies. Six-month-old female ovariectomized (OVX) Sprague-Dawley rats were cycled through various sequences of pharmacological treatments [alendronate (Aln), raloxifene (Ral) and human parathyroid hormone-1,34 (PTH)] for three month intervals, over nine months. Linear nanoindentation mapping was used to determine Young's modulus in perilacunar and bone matrix regions around cortical bone osteocyte lacunae. Measurements of lacunar diameter and density were completed. Treatment-related differences in Young's modulus in the perilacunar and bone matrix regions were not observed. We confirmed previous data that showed that the bone matrix region was stiffer than the perilacunar matrix region. Whole bone material properties were correlated to perilacunar matrix stiffness. Finite element models predicted a range of mechanical strain amplification factors estimated at the osteocyte across treatment groups. In summary, though the perilacunar matrix near cortical osteocyte lacuna is not as stiff as bone matrix further away, osteoporosis treatment agents do not affect the stiffness of bone tissue near osteocyte lacunae. Monotherapy with osteoporosis treatment agents does not affect the stiffness of bone tissue around osteocyte lacunae. Sequential use of osteoporosis treatment agents does not affect bone tissue stiffness around osteocyte lacunae. Perilacunar cortical bone tissue is not as stiff as bone matrix further from osteocyte lacunae. Whole bone material properties are negatively correlated to the stiffness of perilacunar bone tissue.
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Heinonen V, Ruotsalainen TJ, Paavola L, Mikkonen JJ, Asikainen P, Koistinen AP, Kullaa AM. Alveolar bone remodeling after tooth extraction in irradiated mandible: An experimental study with canine model. Ultrastruct Pathol 2018; 42:124-132. [PMID: 29424622 DOI: 10.1080/01913123.2017.1422829] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVES The aim of the present study is to investigate the morphological and cellular changes in dental extraction socket that has been irradiated after the tooth extraction and to describe morphological characteristics of the osteocytes and osteocyte-lacunar-canalicular network (LCN) by scanning electron microscopy (SEM). MATERIAL AND METHODS Five beagle dogs aged 1-2 years were used in this study. One side of each mandible was irradiated in two sessions and the other side of mandible (non-irradiated) served as a control. The mandible bone blocks were processed by bulk staining en bloc in basic fuchsin and the specimens were embedded routinely in polymethyl methacrylate resin without preliminary decalcification. All blocks were subjected to micro-CT imaging, after that the specimens were prepared for light microscopy and SEM. RESULTS Alterations in bone macrostructure are minimal in irradiated bone, but the changes in LCN are clear. In the area of the tooth extraction socket, the connections of osteocytes to the vessels and to neighboring osteocytes were not observed both in irradiated and nonirradiated bone. However, osteoclasts were located in the bone surface entering inside to the bone between osteons. In the lamellar bone of lateral sides, a decrease in canalicular connections between osteocytes and periosteum was found in irradiated bone as compared to the non-irradiated side. CONCLUSIONS The novelty of the present study is that radiation disrupts osteocytes and their dendrites.
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Affiliation(s)
- Venni Heinonen
- a Department of Oral Diagnostic Sciences, Institute of Dentistry , University of Eastern Finland , Kuopio , Finland.,b Dental Education clinic , Kuopio , Finland
| | - Timo J Ruotsalainen
- c Research Group of Oral Health Sciences, Faculty of Medicine , University of Oulu and Oulu University Hospital , Oulu , Finland
| | - Lauri Paavola
- a Department of Oral Diagnostic Sciences, Institute of Dentistry , University of Eastern Finland , Kuopio , Finland
| | - Jopi J Mikkonen
- a Department of Oral Diagnostic Sciences, Institute of Dentistry , University of Eastern Finland , Kuopio , Finland.,d SIB Labs , University of Eastern Finland , Kuopio , Finland
| | | | | | - Arja M Kullaa
- a Department of Oral Diagnostic Sciences, Institute of Dentistry , University of Eastern Finland , Kuopio , Finland.,b Dental Education clinic , Kuopio , Finland.,c Research Group of Oral Health Sciences, Faculty of Medicine , University of Oulu and Oulu University Hospital , Oulu , Finland
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Iordachescu A, Amin HD, Rankin SM, Williams RL, Yapp C, Bannerman A, Pacureanu A, Addison O, Hulley PA, Grover LM. An In Vitro Model for the Development of Mature Bone Containing an Osteocyte Network. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/adbi.201700156] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Alexandra Iordachescu
- School of Chemical Engineering; University of Birmingham; Edgbaston Birmingham B15 2TT UK
- Botnar Research Centre (NDORMS); University of Oxford; Old Road Headington Oxford OX3 7LD UK
| | - Harsh D. Amin
- Inflammation, Development and Repair; National Heart & Lung Institute; Faculty of Medicine; Imperial College London; London SW7 2AZ UK
- Centre for Blast Injury Studies; Department of Bioengineering; Imperial College London; London SW7 2AZ UK
| | - Sara M. Rankin
- Inflammation, Development and Repair; National Heart & Lung Institute; Faculty of Medicine; Imperial College London; London SW7 2AZ UK
- Centre for Blast Injury Studies; Department of Bioengineering; Imperial College London; London SW7 2AZ UK
| | - Richard L. Williams
- School of Chemical Engineering; University of Birmingham; Edgbaston Birmingham B15 2TT UK
| | - Clarence Yapp
- Botnar Research Centre (NDORMS); University of Oxford; Old Road Headington Oxford OX3 7LD UK
- Department of Cell Biology; Harvard Medical School; 240 Longwood Ave Boston MA 02115 USA
| | - Alistair Bannerman
- School of Chemical Engineering; University of Birmingham; Edgbaston Birmingham B15 2TT UK
| | - Alexandra Pacureanu
- European Synchrotron Radiation Facility; Beamline Groups Unit; 71 avenue des Martyrs 38000 Grenoble France
| | - Owen Addison
- School of Dentistry; University of Birmingham; 5 Mill Pool Way Edgbaston Birmingham B5 7EG UK
| | - Philippa A. Hulley
- Botnar Research Centre (NDORMS); University of Oxford; Old Road Headington Oxford OX3 7LD UK
| | - Liam M. Grover
- School of Chemical Engineering; University of Birmingham; Edgbaston Birmingham B15 2TT UK
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Binkley DM, Grandfield K. Advances in Multiscale Characterization Techniques of Bone and Biomaterials Interfaces. ACS Biomater Sci Eng 2017; 4:3678-3690. [PMID: 33429593 DOI: 10.1021/acsbiomaterials.7b00420] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The success of osseointegrated biomaterials often depends on the functional interface between the implant and mineralized bone tissue. Several parallels between natural and synthetic interfaces exist on various length scales from the microscale toward the cellular and the atomic scale structure. Interest lies in the development of more sophisticated methods to probe these hierarchical levels in tissues at both biomaterials interfaces and natural tissue interphases. This review will highlight new and emerging perspectives toward understanding mineralized tissues, particularly bone tissue, and interfaces between bone and engineered biomaterials at multilength scales and with multidimensionality. Emphasis will be placed on highlighting novel and correlative X-ray, ion, and electron beam imaging approaches, such as electron tomography, atom probe tomography, and in situ microscopies, as well as spectroscopic and mechanical characterizations. These less conventional approaches to imaging biomaterials are contributing to the evolution of the understanding of the structure and organization in bone and bone integrating materials.
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Abstract
PURPOSE OF REVIEW The bone is able to adapt its structure to mechanical signals via the bone remodeling process governed by mechanosensitive osteocytes. With aging, an imbalance in bone remodeling results in osteoporosis. In this review, we hypothesized that changes in lacunar morphology underlie the decreased bone mechanoresponsiveness to mechanical loading with aging. RECENT FINDINGS Several studies have reported considerable variations in the shape of osteocytes and their lacunae with aging. Since osteocytes can sense matrix strain directly via their cell bodies, the variations in osteocyte morphology may cause changes in osteocyte mechanosensitivity. As a consequence, the load-adaptive response of osteocytes may change with aging, even when mechanical loading would remain unchanged. Though extensive quantitative data is lacking, evidence exists that the osteocyte lacunae are becoming smaller and more spherical with aging. Future dedicated studies might reveal whether these changes would affect osteocyte mechanosensation and the subsequent biological response, and whether this is (one of) the pathways involved in age-related bone loss.
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Affiliation(s)
- Haniyeh Hemmatian
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300c, 3001 Leuven, Belgium
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Astrid D. Bakker
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Jenneke Klein-Nulend
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - G. Harry van Lenthe
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300c, 3001 Leuven, Belgium
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Mosey H, Núñez JA, Goring A, Clarkin CE, Staines KA, Lee PD, Pitsillides AA, Javaheri B. Sost Deficiency does not Alter Bone's Lacunar or Vascular Porosity in Mice. FRONTIERS IN MATERIALS 2017; 4:27. [PMID: 29349060 PMCID: PMC5769812 DOI: 10.3389/fmats.2017.00027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
SCLEROSTIN (Sost) is expressed predominantly in osteocytes acting as a negative regulator of bone formation. In humans, mutations in the SOST gene lead to skeletal overgrowth and increased bone mineral density, suggesting that SCLEROSTIN is a key regulator of bone mass. The function of SCLEROSTIN as an inhibitor of bone formation is further supported by Sost knockout (KO) mice which display a high bone mass with elevated bone formation. Previous studies have indicated that Sost exerts its effect on bone formation through Wnt-mediated regulation of osteoblast differentiation, proliferation, and activity. Recent in vitro studies have also suggested that SCLEROSTIN regulates angiogenesis and osteoblast-to-osteocyte transition. Despite this wealth of knowledge of the mechanisms responsible for SCLEROSTIN action, no previous studies have examined whether SCLEROSTIN regulates osteocyte and vascular configuration in cortices of mouse tibia. Herein, we image tibiae from Sost KO mice and their wild-type (WT) counterparts with high-resolution CT to examine whether lack of SCLEROSTIN influences the morphometric properties of lacunae and vascular canal porosity relating to osteocytes and vessels within cortical bone. Male Sost KO and WT mice (n = 6/group) were sacrificed at 12 weeks of age. Fixed tibiae were analyzed using microCT to examine cortical bone mass and architecture. Then, samples were imaged by using benchtop and synchrotron nano-computed tomography at the tibiofibular junction. Our data, consistent with previous studies show that, Sost deficiency leads to significant enhancement of bone mass by cortical thickening and bigger cross-sectional area and we find that this occurs without modifications of tibial ellipticity, a measure of bone shape. In addition, our data show that there are no significant differences in any lacunar or vascular morphometric or geometric parameters between Sost KO mouse tibia and WT counterparts. We, therefore, conclude that the significant increases in bone mass induced by Sost deficiency are not accompanied by any significant modification in the density, organization, or shape of osteocyte lacunae or vascular content within the cortical bone. These data may imply that SCLEROSTIN does not modify the frequency of osteocytogenic recruitment of osteoblasts to initiate terminal osteocytic differentiation in mice.
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Affiliation(s)
- Henry Mosey
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, United Kingdom
| | - Juan A. Núñez
- Faculty of Natural and Environmental Sciences, Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Alice Goring
- Faculty of Natural and Environmental Sciences, Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Claire E. Clarkin
- Faculty of Natural and Environmental Sciences, Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Katherine A. Staines
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, United Kingdom
| | - Peter D. Lee
- Manchester X-Ray Imaging Facility, University of Manchester, Manchester, United Kingdom
| | - Andrew A. Pitsillides
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, United Kingdom
| | - Behzad Javaheri
- Skeletal Biology Group, Comparative Biomedical Sciences, The Royal Veterinary College, London, United Kingdom
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Hemmatian H, Laurent MR, Ghazanfari S, Vanderschueren D, Bakker AD, Klein-Nulend J, van Lenthe GH. Accuracy and reproducibility of mouse cortical bone microporosity as quantified by desktop microcomputed tomography. PLoS One 2017; 12:e0182996. [PMID: 28797125 PMCID: PMC5552254 DOI: 10.1371/journal.pone.0182996] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 07/27/2017] [Indexed: 02/07/2023] Open
Abstract
Bone's microporosity plays important roles in bone biology and bone mechanical quality. In this study, we explored the accuracy and reproducibility of nondestructive desktop μCT for 3D visualization and subsequent morphometric analysis of mouse cortical bone microporosity including the vascular canal network and osteocyte lacunae. The accuracy of measurements was evaluated in five murine fibula using confocal laser scanning microscopy (CLSM) in conjunction with Fluorescein isothiocyanate (FITC) staining as the reference method. The reproducibility of μCT-derived cortical bone microstructural indices was examined in 10 fibulae of C57Bl/6J male mice at a nominal resolution of 700 nanometer. Three repeated measurements were made on different days. An excellent correlation between μCT and CLSM was observed for both mean lacuna volume (r = 0.98, p = 0.002) and for mean lacuna orientation (r = 0.93, p = 0.02). Whereas the two techniques showed no significant differences for these parameters, the mean lacuna sphericity acquired from μCT was significantly higher than CLSM (p = 0.01). Reproducibility was high, with precision errors (PE) of 1.57-4.69% for lacuna parameters, and of 1.01-9.45% for vascular canal parameters. Intraclass correlation coefficient (ICC) showed a high reliability of the measurements, ranging from 0.998-1.000 for cortical parameters, 0.973-0.999 for vascular canal parameters and 0.755-0.991 for lacuna parameters. In conclusion, desktop μCT is a valuable tool to quantify the 3D characteristics of bone vascular canals as well as lacunae which can be applied to intact murine bones with high accuracy and reproducibility. Thus, μCT might be an important tool to improve our understanding of the physiological and biomechanical significance of these cannular and lacunar structure in cortical bone.
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Affiliation(s)
- Haniyeh Hemmatian
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Michaël R. Laurent
- Laboratory of Molecular Endocrinology, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
- Gerontology and Geriatrics, Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium
| | - Samaneh Ghazanfari
- Aachen-Maastricht Institute for Biobased Materials, Department of Humanities and Sciences, Maastricht University, Geleen, The Netherlands
| | - Dirk Vanderschueren
- Clinical and Experimental Endocrinology, Department of Clinical and Experimental Medicine, KU Leuven, Leuven, Belgium
| | - Astrid D. Bakker
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Jenneke Klein-Nulend
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - G. Harry van Lenthe
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
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Jähn K, Kelkar S, Zhao H, Xie Y, Tiede-Lewis LM, Dusevich V, Dallas SL, Bonewald LF. Osteocytes Acidify Their Microenvironment in Response to PTHrP In Vitro and in Lactating Mice In Vivo. J Bone Miner Res 2017; 32:1761-1772. [PMID: 28470757 PMCID: PMC5550338 DOI: 10.1002/jbmr.3167] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 04/04/2017] [Accepted: 05/01/2017] [Indexed: 11/10/2022]
Abstract
Osteocytes appear to mobilize calcium within minutes in response to PTH injections; we have previously shown that osteocytes remove their perilacunar matrix during lactation through activation of the PTH type 1 receptor. Mechanisms utilized by osteocytes to mobilize calcium are unknown but we hypothesized that the molecular components may be similar to those used by osteoclasts. Here we show, using IDG-SW3 cells that ATP6V0D2, an essential component of vacuolar ATPase in osteoclasts, and other genes associated with osteoclastic bone resorption, increase with osteoblast to osteocyte differentiation. Furthermore, PTHrP increases ATP6V0D2 expression and induces proton generation by primary osteocytes, which is blocked by bafilomycin, a vacuolar ATPase inhibitor. These in vitro proton measurements raised the question of osteocyte viability in an acidic environment. Interestingly, osteocytes, showed enhanced viability at pH as low as 5 compared to osteoblasts and fibroblasts in vitro. To study in vivo acidification by osteocytes, virgin and lactating CD1 mice on a low calcium diet were injected with the pH indicator dye, acridine orange, and their osteocyte lacuno-canalicular system imaged by confocal microscopy. Lower pH was observed in lactating compared to virgin animals. In addition, a novel transgenic mouse line with a topaz variant of green fluorescent protein (GFPtpz)-tagged collagen α2(I) chain was used. Instead of the expected reduction in GFP-fluorescence only in the perilacunar matrix, reduced fluorescence was observed in the entire bone matrix of lactating mice. Based on our experiments showing quenching of GFP in vitro, we propose that the observed reduction in GFP fluorescence in lactating mice is due to quenching of GFP by the acidic pH generated by osteocytes. Together these findings provide novel mechanistic insight into how osteocytes remove calcium from their perilacunar/pericanalicular matrices through active acidification of their microenvironment and show that osteocytes, like osteoclasts, are resistant to the negative effects of acid on viability. © 2017 American Society for Bone and Mineral Research.
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Affiliation(s)
- Katharina Jähn
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Shilpa Kelkar
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Hong Zhao
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Yixia Xie
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - LeAnn M Tiede-Lewis
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Vladimir Dusevich
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Lynda F Bonewald
- Department of Oral and Craniofacial Biology, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
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50
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Ashique AM, Hart LS, Thomas CDL, Clement JG, Pivonka P, Carter Y, Mousseau DD, Cooper DML. Lacunar-canalicular network in femoral cortical bone is reduced in aged women and is predominantly due to a loss of canalicular porosity. Bone Rep 2017; 7:9-16. [PMID: 28752112 PMCID: PMC5517690 DOI: 10.1016/j.bonr.2017.06.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/29/2017] [Accepted: 06/27/2017] [Indexed: 11/29/2022] Open
Abstract
The lacunar-canalicular network (LCN) of bone contains osteocytes and their dendritic extensions, which allow for intercellular communication, and are believed to serve as the mechanosensors that coordinate the processes of bone modeling and remodeling. Imbalances in remodeling, for example, are linked to bone disease, including fragility associated with aging. We have reported that there is a reduction in scale for one component of the LCN, osteocyte lacunar volume, across the human lifespan in females. In the present study, we explore the hypothesis that canalicular porosity also declines with age. To visualize the LCN and to determine how its components are altered with aging, we examined samples from young (age: 20–23 y; n = 5) and aged (age: 70–86 y; n = 6) healthy women donors utilizing a fluorescent labelling technique in combination with confocal laser scanning microscopy. A large cross-sectional area of cortical bone spanning the endosteal to periosteal surfaces from the anterior proximal femoral shaft was examined in order to account for potential trans-cortical variation in the LCN. Overall, we found that LCN areal fraction was reduced by 40.6% in the samples from aged women. This reduction was due, in part, to a reduction in lacunar density (21.4% decline in lacunae number per given area of bone), but much more so due to a 44.6% decline in canalicular areal fraction. While the areal fraction of larger vascular canals was higher in endosteal vs. periosteal regions for both age groups, no regional differences were observed in the areal fractions of the LCN and its components for either age group. Our data indicate that the LCN is diminished in aged women, and is largely due to a decline in the canalicular areal fraction, and that, unlike vascular canal porosity, this diminished LCN is uniform across the cortex. The lacunar-canalicular network (LCN) is reduced by 40.6% in aged women The lacunar density (lacunae number per given area of bone) is reduced by 21.4% in aged women The reduction in LCN in aged women is primarily due to a 44.6% loss of canaliculi No endosteal vs. periosteal regional differences were observed in the LCN and its components in either young or aged women A reduction in canaliculi with age may contribute to bone fragility in aged women
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Affiliation(s)
- A M Ashique
- Department of Anatomy & Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - L S Hart
- Department of Anatomy & Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - C D L Thomas
- Melbourne Dental School, University of Melbourne, Melbourne, VIC, Australia
| | - J G Clement
- Melbourne Dental School, University of Melbourne, Melbourne, VIC, Australia
| | - P Pivonka
- St. Vincent's Department of Surgery, University of Melbourne, Melbourne, VIC, Australia.,School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Y Carter
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA
| | - D D Mousseau
- Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - D M L Cooper
- Department of Anatomy & Cell Biology, University of Saskatchewan, Saskatoon, SK, Canada
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