1
|
Vom Scheidt A, Krug J, Goggin P, Bakker AD, Busse B. 2D vs. 3D Evaluation of Osteocyte Lacunae - Methodological Approaches, Recommended Parameters, and Challenges: A Narrative Review by the European Calcified Tissue Society (ECTS). Curr Osteoporos Rep 2024; 22:396-415. [PMID: 38980532 PMCID: PMC11324773 DOI: 10.1007/s11914-024-00877-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/11/2024] [Indexed: 07/10/2024]
Abstract
PURPOSE OF REVIEW Quantification of the morphology of osteocyte lacunae has become a powerful tool to investigate bone metabolism, pathologies and aging. This review will provide a brief overview of 2D and 3D imaging methods for the determination of lacunar shape, orientation, density, and volume. Deviations between 2D-based and 3D-based lacunar volume estimations are often not sufficiently addressed and may give rise to contradictory findings. Thus, the systematic error arising from 2D-based estimations of lacunar volume will be discussed, and an alternative calculation proposed. Further, standardized morphological parameters and best practices for sampling and segmentation are suggested. RECENT FINDINGS We quantified the errors in reported estimation methods of lacunar volume based on 2D cross-sections, which increase with variations in lacunar orientation and histological cutting plane. The estimations of lacunar volume based on common practice in 2D imaging methods resulted in an underestimation of lacunar volume of up to 85% compared to actual lacunar volume in an artificial dataset. For a representative estimation of lacunar size and morphology based on 2D images, at least 400 lacunae should be assessed per sample.
Collapse
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
| |
Collapse
|
2
|
Wang S, Xiao L, Prasadam I, Crawford R, Zhou Y, Xiao Y. Inflammatory macrophages interrupt osteocyte maturation and mineralization via regulating the Notch signaling pathway. Mol Med 2022; 28:102. [PMID: 36058911 PMCID: PMC9441044 DOI: 10.1186/s10020-022-00530-4] [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: 03/16/2022] [Accepted: 08/10/2022] [Indexed: 11/12/2022] Open
Abstract
Background It is well-known that both macrophages and osteocytes are critical regulators of osteogenesis and osteoclastogenesis, yet there is limited understanding of the macrophage-osteocyte interaction, and how their crosstalk could affect bone homeostasis and mineralization. This research therefore aims to investigate the effects of macrophage polarization on osteocyte maturation and mineralization process. Methods A macrophage-derived conditioned medium based osteocyte culture was set up to investigate the impact of macrophages on osteocyte maturation and terminal mineralization. Surgically induced osteoarthritis (OA) rat model was used to further investigate the macrophage-osteocyte interaction in inflammatory bone remodeling, as well as the involvement of the Notch signaling pathway in the mineralization process. Results Our results identified that osteocytes were confined in an immature stage after the M1 macrophage stimulation, showing a more rounded morphology, higher expression of early osteocyte marker E11, and significantly lower expression of mature osteocyte marker DMP1. Immature osteocytes were also found in inflammatory bone remodeling areas, showing altered morphology and mineralized structures similar to those observed under the stimulation of M1 macrophages in vitro, suggesting that M1 macrophages negatively affect osteocyte maturation, leading to abnormal mineralization. The Notch signaling pathway was found to be down regulated in M1 macrophage-stimulated osteocytes as well as osteocytes in inflammatory bone. Overexpression of the Notch signaling pathway in osteocytes showed a significant circumvention on the negative effects from M1 macrophage. Conclusion Taken together, our findings provide valuable insights into the mechanisms involved in abnormal bone mineralization under inflammatory conditions. Supplementary Information The online version contains supplementary material available at 10.1186/s10020-022-00530-4.
Collapse
Affiliation(s)
- Shengfang Wang
- School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.,Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, 4000, Australia.,Australia-China Centre for Tissue Engineering and Regenerative Medicine, Brisbane, QLD, 4000, Australia
| | - Lan Xiao
- School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.,Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, 4000, Australia.,Australia-China Centre for Tissue Engineering and Regenerative Medicine, Brisbane, QLD, 4000, Australia
| | - Indira Prasadam
- School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.,Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, 4000, Australia.,Australia-China Centre for Tissue Engineering and Regenerative Medicine, Brisbane, QLD, 4000, Australia
| | - Ross Crawford
- School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.,Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, 4000, Australia.,Australia-China Centre for Tissue Engineering and Regenerative Medicine, Brisbane, QLD, 4000, Australia
| | - Yinghong Zhou
- School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia. .,Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, 4000, Australia. .,Australia-China Centre for Tissue Engineering and Regenerative Medicine, Brisbane, QLD, 4000, Australia. .,School of Dentistry, Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, QLD, 4006, Australia.
| | - Yin Xiao
- School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia. .,Centre for Biomedical Technologies, Queensland University of Technology, Brisbane, QLD, 4000, Australia. .,Australia-China Centre for Tissue Engineering and Regenerative Medicine, Brisbane, QLD, 4000, Australia.
| |
Collapse
|
3
|
Eren ED, Nijhuis WH, van der Weel F, Dede Eren A, Ansari S, Bomans PHH, Friedrich H, Sakkers RJ, Weinans H, de With G. Multiscale characterization of pathological bone tissue. Microsc Res Tech 2021; 85:469-486. [PMID: 34490967 PMCID: PMC9290679 DOI: 10.1002/jemt.23920] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/16/2021] [Accepted: 08/18/2021] [Indexed: 11/09/2022]
Abstract
Bone is a complex natural material with a complex hierarchical multiscale organization, crucial to perform its functions. Ultrastructural analysis of bone is crucial for our understanding of cell to cell communication, the healthy or pathological composition of bone tissue, and its three‐dimensional (3D) organization. A variety of techniques has been used to analyze bone tissue. This article describes a combined approach of optical, scanning electron, and transmission electron microscopy for the ultrastructural analysis of bone from the nanoscale to the macroscale, as illustrated by two pathological bone tissues. By following a top‐down approach to investigate the multiscale organization of pathological bones, quantitative estimates were made in terms of calcium content, nearest neighbor distances of osteocytes, canaliculi diameter, ordering, and D‐spacing of the collagen fibrils, and the orientation of intrafibrillar minerals which enable us to observe the fine structural details. We identify and discuss a series of two‐dimensional (2D) and 3D imaging techniques that can be used to characterize bone tissue. By doing so we demonstrate that, while 2D imaging techniques provide comparable information from pathological bone tissues, significantly different structural details are observed upon analyzing the pathological bone tissues in 3D. Finally, particular attention is paid to sample preparation for and quantitative processing of data from electron microscopic analysis.
Collapse
Affiliation(s)
- E Deniz Eren
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Wouter H Nijhuis
- Department of Orthopedic Surgery, University Medical Centre Utrecht, Wilhelmina Children's Hospital, Utrecht, The Netherlands
| | - Freek van der Weel
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Aysegul Dede Eren
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, The Netherlands.,Eindhoven University of Technology, Department of Biomedical Engineering, Biointerface Science, Eindhoven, The Netherlands
| | - Sana Ansari
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, The Netherlands.,Orthopedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Paul H H Bomans
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Heiner Friedrich
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Ralph J Sakkers
- Department of Orthopedic Surgery, University Medical Centre Utrecht, Wilhelmina Children's Hospital, Utrecht, The Netherlands
| | - Harrie Weinans
- Department of Orthopedic Surgery, University Medical Centre Utrecht, Wilhelmina Children's Hospital, Utrecht, The Netherlands.,TU Delft, Department of Biomechanical Engineering, Delft, The Netherlands
| | - Gijsbertus de With
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands
| |
Collapse
|
4
|
Szarek P, Lilledahl MB, Emery NC, Lewis CG, Pierce DM. The zonal evolution of collagen-network morphology quantified in early osteoarthritic grades of human cartilage. OSTEOARTHRITIS AND CARTILAGE OPEN 2020; 2:100086. [DOI: 10.1016/j.ocarto.2020.100086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/14/2020] [Indexed: 10/23/2022] Open
|
5
|
Wang X, Lu Y, Wang W, Wang Q, Liang J, Fan Y, Zhang X. Effect of different aged cartilage ECM on chondrogenesis of BMSCs in vitro and in vivo. Regen Biomater 2020; 7:583-595. [PMID: 33365144 PMCID: PMC7748452 DOI: 10.1093/rb/rbaa028] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/23/2020] [Accepted: 06/07/2020] [Indexed: 12/11/2022] Open
Abstract
Extracellular matrix (ECM)-based biomaterials are promising candidates in cartilage tissue engineering by simulating the native microenvironment to regulate the chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) without exogenous growth factors. The biological properties of ECM scaffolds are primarily depended on the original source, which would directly influence the chondrogenic effects of the ECM materials. Despite the expanding investigations on ECM scaffolds in recent years, the selection of optimized ECM materials in cartilage regeneration was less reported. In this study, we harvested and compared the articular cartilage ECM from newborn, juvenile and adult rabbits. The results demonstrated the significant differences in the mechanical strength, sulphated glycosaminoglycan and collagen contents of the different aged ECM, before and after decellularization. Consequently, different compositional and mechanical properties were shown in the three ECM-based collagen hydrogels, which exerted age-dependent chondrogenic inducibility. In general, both in vitro and in vivo results suggested that the newborn ECM promoted the most chondrogenesis of BMSCs but led to severe matrix calcification. In contrast, BMSCs synthesized the lowest amount of cartilaginous matrix with minimal calcification with adult ECM. The juvenile ECM achieved the best overall results in promoting chondrogenesis of BMSCs and preventing matrix calcification. Together, this study provides important information to our current knowledge in the design of future ECM-based biomaterials towards a successful repair of articular cartilage.
Collapse
Affiliation(s)
- Xiuyu Wang
- Guangxi Engineering Center in Biomedical Materials for Tissue and Organ Regeneration, Guangxi Collaborative Innovation Center for Biomedicine, Guangxi Medical University, Nanning 530021, China.,National Engineering Research Center for Biomaterials, Sichuan University, Wangjiang Road 29, Chengdu 610064, China
| | - Yan Lu
- National Engineering Research Center for Biomaterials, Sichuan University, Wangjiang Road 29, Chengdu 610064, China
| | - Wan Wang
- Guangxi Engineering Center in Biomedical Materials for Tissue and Organ Regeneration, Guangxi Collaborative Innovation Center for Biomedicine, Guangxi Medical University, Nanning 530021, China.,National Engineering Research Center for Biomaterials, Sichuan University, Wangjiang Road 29, Chengdu 610064, China
| | - Qiguang Wang
- National Engineering Research Center for Biomaterials, Sichuan University, Wangjiang Road 29, Chengdu 610064, China
| | - Jie Liang
- National Engineering Research Center for Biomaterials, Sichuan University, Wangjiang Road 29, Chengdu 610064, China
| | - Yujiang Fan
- Guangxi Engineering Center in Biomedical Materials for Tissue and Organ Regeneration, Guangxi Collaborative Innovation Center for Biomedicine, Guangxi Medical University, Nanning 530021, China.,National Engineering Research Center for Biomaterials, Sichuan University, Wangjiang Road 29, Chengdu 610064, China
| | - Xingdong Zhang
- National Engineering Research Center for Biomaterials, Sichuan University, Wangjiang Road 29, Chengdu 610064, China
| |
Collapse
|
6
|
Shao J, Zhou Y, Lin J, Nguyen TD, Huang R, Gu Y, Friis T, Crawford R, Xiao Y. Notch expressed by osteocytes plays a critical role in mineralisation. J Mol Med (Berl) 2018; 96:333-347. [PMID: 29455246 DOI: 10.1007/s00109-018-1625-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 01/04/2018] [Accepted: 02/05/2018] [Indexed: 12/21/2022]
Abstract
Notch is actively involved in various life processes including osteogenesis; however, the role of Notch signalling in the terminal mineralisation of bone is largely unknown. In this study, it was noted that Hey1, a downstream target of Notch signalling was highly expressed in mature osteocytes compared to osteoblasts, indicating a potential role of Notch in osteocytes. Using a recently developed thermosensitive cell line (IDG-SW3), we demonstrated that dentin matrix acidic phosphoprotein 1 (DMP1) expression was inhibited and mineralisation process was significantly altered when Notch pathway was inactivated via administration of N-[N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), an inhibitor of Notch. Dysregulation of Notch in osteocyte differentiation can result in spontaneous deposition of calcium phosphate on collagen fibrils, disturbed transportation of intracellular mineral vesicles, alteration of mineral crystal structure, decreased bonding force between minerals and organic matrix, and suppression of dendrite development coupled with decreased expression of E11. In conclusion, the evidence presented here suggests that Notch plays a critical role in osteocyte differentiation and biomineralisation process. KEY MESSAGES Notch plays a regulatory role in osteocyte phenotype. Notch modulates the mineralisation mediated by osteocytes. Notch activity influences the ultrastructural properties of bone mineralisation.
Collapse
Affiliation(s)
- Jin Shao
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Yinghong Zhou
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Jinying Lin
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
- Department of Implantology, Xiamen Stomatological Research Institute, Xiamen Stomatological Hospital, Fujian, 361000, China
| | - Trung Dung Nguyen
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, 4059, Australia
- Department of Aerospace and Mechanical Engineering, College of Engineering, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Rong Huang
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Yuantong Gu
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Thor Friis
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Ross Crawford
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia
- The Prince Charles Hospital, Brisbane, QLD, 4059, Australia
| | - Yin Xiao
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia.
- The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, QLD, 4059, Australia.
| |
Collapse
|
7
|
Danilchik M, Tumarkin T. Exosomal trafficking in Xenopus development. Genesis 2017; 55. [PMID: 28095652 DOI: 10.1002/dvg.23011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 11/30/2016] [Accepted: 12/02/2016] [Indexed: 12/16/2022]
Abstract
Exosomes are small extracellular vesicles (EVs) secreted by many cell types in both normal and pathogenic circumstances. Because EVs, particularly exosomes, are known to transfer biologically active proteins, RNAs and lipids between cells, they have recently become the focus of intense interest as potential mediators of cell-cell communication, particularly in long-range and juxtacrine signaling events associated with adaptive immune function and progression of cancer. Among the EVs, exosomes appear particularly adapted for long-range delivery of cargoes between cells. Because of their association with disease states, the exciting potential for exosomes to serve as diagnostic biomarkers and as target-specific biomolecule delivery vehicles has stimulated a broad range of biomedical investigations to learn how exosomes are generated, what their cargoes are, and how they might be tailored for uptake by remote targets. Addressing these questions requires experimental models in which biochemically useful amounts of material can be harvested, gene expression easily manipulated, and interpretable biological assays developed. The early Xenopus embryo fulfills these model-system ideals in an in vivo context: during morphogenesis the embryo develops several large, fluid-filled extracellular compartments across which numerous tissue-specifying signals must cross, and which are abundantly endowed with exosomes and other EVs. Importantly, certain surface-facing tissues avidly ingest EVs during gastrulation. Recent work has demonstrated that EVs can be isolated from these interstitial spaces in amounts suitable for proteomic and transcriptomic analysis. With its large numbers, great cell size, well-understood fate map, and tolerance of a variety of experimental approaches, the Xenopus embryo provides a unique opportunity to both understand and manipulate the basic cell biology of exosomal trafficking in the context of an intact organism.
Collapse
Affiliation(s)
- Michael Danilchik
- Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon, 97239
| | - Tess Tumarkin
- Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon, 97239
| |
Collapse
|
8
|
Abstract
BACKGROUND Mandibular condyle cartilage (MCC) has a unique structure among articular cartilages; however, little is known about its nanoscale collagen network architecture, hampering design of regeneration therapies and rigorous evaluation of regeneration experiment outcomes in preclinical research. Helium ion microscopy is a novel technology with a long depth of field that is uniquely suited to imaging open 3D collagen networks at multiple scales without obscuring conductive coatings. OBJECTIVE The objective of this research was to image, at the micro- and nanoscales, the depth-dependent MCC collagen network architecture. DESIGN MCC was collected from New Zealand white rabbits. Images of MCC zones were acquired using helium ion, transmission electron, and light microscopy. Network fibril and canal diameters were measured. RESULTS For the first time, the MCC was visualized as a 3D collagen fibril structure at the nanoscale, the length scale of network assembly. Fibril diameters ranged from 7 to 110 nm and varied by zone. The articular surface was composed of a fine mesh that was woven through thin layers of larger fibrils. The fibrous zone was composed of approximately orthogonal lamellae of aligned fibrils. Fibrocyte processes surrounded collagen bundles forming extracellular compartments. The proliferative, mature, and hypertrophic zones were composed of a branched network that was progressively remodeled to accommodate chondrocyte hypertrophy. Osteoid fibrils were woven around osteoblast cytoplasmic processes to create numerous canals similar in size to canaliculi of mature bone. CONCLUSION This multiscale investigation advances our foundational understanding of the complex, layered 3D architecture of the MCC collagen network.
Collapse
Affiliation(s)
- Wendy S. Vanden Berg-Foels
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT, USA
- Department of Bioengineering, Clemson University, Clemson, SC, USA
- Department of Oral Health Sciences, Medical University of South Carolina, Charleston, SC, USA
| |
Collapse
|
9
|
Hunziker EB, Lippuner K, Shintani N. How best to preserve and reveal the structural intricacies of cartilaginous tissue. Matrix Biol 2014; 39:33-43. [PMID: 25173436 DOI: 10.1016/j.matbio.2014.08.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
No single processing technique is capable of optimally preserving each and all of the structural entities of cartilaginous tissue. Hence, the choice of methodology must necessarily be governed by the nature of the component that is targeted for analysis, for example, fibrillar collagens or proteoglycans within the extracellular matrix, or the chondrocytes themselves. This article affords an insight into the pitfalls that are to be encountered when implementing the available techniques and how best to circumvent them. Adult articular cartilage is taken as a representative pars pro toto of the different bodily types. In mammals, this layer of tissue is a component of the synovial joints, wherein it fulfills crucial and diverse biomechanical functions. The biomechanical functions of articular cartilage have their structural and molecular correlates. During the natural course of postnatal development and after the onset of pathological disease processes, such as osteoarthritis, the tissue undergoes structural changes which are intimately reflected in biomechanical modulations. The fine structural intricacies that subserve the changes in tissue function can be accurately assessed only if they are faithfully preserved at the molecular level. For this reason, a careful consideration of the tissue-processing technique is indispensable. Since, as aforementioned, no single methodological tool is capable of optimally preserving all constituents, the approach must be pre-selected with a targeted structure in view. Guidance in this choice is offered.
Collapse
Affiliation(s)
- Ernst B Hunziker
- Departments of Osteoporosis, Orthopaedic Surgery and Clinical Research, Inselspital, University of Bern, Murtenstrasse 35, P.O. Box 54, 3010 Bern, Switzerland.
| | - Kurt Lippuner
- Departments of Osteoporosis, Orthopaedic Surgery and Clinical Research, Inselspital, University of Bern, Murtenstrasse 35, P.O. Box 54, 3010 Bern, Switzerland
| | - Nahoko Shintani
- Departments of Osteoporosis, Orthopaedic Surgery and Clinical Research, Inselspital, University of Bern, Murtenstrasse 35, P.O. Box 54, 3010 Bern, Switzerland
| |
Collapse
|
10
|
Schwartz AG, Pasteris JD, Genin GM, Daulton TL, Thomopoulos S. Mineral distributions at the developing tendon enthesis. PLoS One 2012; 7:e48630. [PMID: 23152788 PMCID: PMC3494702 DOI: 10.1371/journal.pone.0048630] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 10/03/2012] [Indexed: 01/08/2023] Open
Abstract
Tendon attaches to bone across a functionally graded interface, “the enthesis”. A gradient of mineral content is believed to play an important role for dissipation of stress concentrations at mature fibrocartilaginous interfaces. Surgical repair of injured tendon to bone often fails, suggesting that the enthesis does not regenerate in a healing setting. Understanding the development and the micro/nano-meter structure of this unique interface may provide novel insights for the improvement of repair strategies. This study monitored the development of transitional tissue at the murine supraspinatus tendon enthesis, which begins postnatally and is completed by postnatal day 28. The micrometer-scale distribution of mineral across the developing enthesis was studied by X-ray micro-computed tomography and Raman microprobe spectroscopy. Analyzed regions were identified and further studied by histomorphometry. The nanometer-scale distribution of mineral and collagen fibrils at the developing interface was studied using transmission electron microscopy (TEM). A zone (∼20 µm) exhibiting a gradient in mineral relative to collagen was detected at the leading edge of the hard-soft tissue interface as early as postnatal day 7. Nanocharacterization by TEM suggested that this mineral gradient arose from intrinsic surface roughness on the scale of tens of nanometers at the mineralized front. Microcomputed tomography measurements indicated increases in bone mineral density with time. Raman spectroscopy measurements revealed that the mineral-to-collagen ratio on the mineralized side of the interface was constant throughout postnatal development. An increase in the carbonate concentration of the apatite mineral phase over time suggested possible matrix remodeling during postnatal development. Comparison of Raman-based observations of localized mineral content with histomorphological features indicated that development of the graded mineralized interface is linked to endochondral bone formation near the tendon insertion. These conserved and time-varying aspects of interface composition may have important implications for the growth and mechanical stability of the tendon-to-bone attachment throughout development.
Collapse
Affiliation(s)
- Andrea G. Schwartz
- Department of Orthopaedic Surgery, Washington University, St. Louis, Missouri, United States of America
| | - Jill D. Pasteris
- Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri, United States of America
| | - Guy M. Genin
- Department of Mechanical Engineering & Materials Science, Washington University, St. Louis, Missouri, United States of America
| | - Tyrone L. Daulton
- Center for Materials Innovation, Washington University, St. Louis, Missouri, United States of America
- Department of Physics, Washington University, St. Louis, Missouri, United States of America
| | - Stavros Thomopoulos
- Department of Orthopaedic Surgery, Washington University, St. Louis, Missouri, United States of America
- * E-mail:
| |
Collapse
|
11
|
Vanden Berg-Foels WS, Scipioni L, Huynh C, Wen X. Helium ion microscopy for high-resolution visualization of the articular cartilage collagen network. J Microsc 2012; 246:168-76. [PMID: 22416783 DOI: 10.1111/j.1365-2818.2012.03606.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The articular cartilage collagen network is an important research focus because network disruption results in cartilage degeneration and patient disability. The recently introduced helium ion microscope (HIM), with its smaller probe size, longer depth of field and charge neutralization, has the potential to overcome the inherent limitations of electron microscopy for visualization of collagen network features, particularly at the nanoscale. In this study, we evaluated the capabilities of the helium ion microscope for high-resolution visualization of the articular cartilage collagen network. Images of rabbit knee cartilage were acquired with a helium ion microscope; comparison images were acquired with a field emission scanning electron microscope (FE-SEM) and a transmission electron microscope (TEM). Sharpness of example high-resolution helium ion microscope and field emission scanning electron microscope images was quantified using the 25-75% rise distance metric. The helium ion microscope was able to acquire high-resolution images with unprecedented clarity, with greater sharpness and three-dimensional-like detail of nanoscale fibril morphologies and fibril connections, in samples without conductive coatings. These nanoscale features could not be resolved by field emission scanning electron microscopy, and three-dimensional network structure could not be visualized with transmission electron microscopy. The nanoscale three-dimensional-like visualization capabilities of the helium ion microscope will enable new avenues of investigation in cartilage collagen network research.
Collapse
|