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Fernandes Da Costa C, Attik N, Gauthier R. Influence of intramedullary pressure on Lacuno-Canalicular fluid flow: A systematic review. Acta Biomater 2024; 178:41-49. [PMID: 38484832 DOI: 10.1016/j.actbio.2024.03.003] [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: 10/26/2023] [Revised: 03/01/2024] [Accepted: 03/06/2024] [Indexed: 03/24/2024]
Abstract
While most of current models investigating bone remodelling are based on matrix deformation, intramedullary pressure also plays a role. Bone remodelling is orchestrated by the Lacuno-Canalicular Network (LCN) fluid-flow. The aim of this review was hence to assess the influence of intramedullary pressure on the fluid circulation within the LCN. Three databases (Science Direct, Web of Science, and PubMed) were used. The first phase of the search returned 731 articles, of which 9 respected the inclusion/exclusion criteria and were included. These studies confirm the association between intramedullary pressure and fluid dynamics in the LCN. Among the included studies, 7 experimental studies using animal models and 2 numerical models were found. The studies were then ranked according to the nature of the applied loading, either axial compression or direct cyclic intramedullary pressure. The current review revealed that there is an influence of intramedullary pressure on LCN fluid dynamics and that this influence depends on the magnitude and the frequency of the applied pressure. Two studies confirmed that the influence was effective even without bone matrix deformation. While intramedullary pressure is closely associated with LCN fluid, there is a severe lack of studies on this topic. STATEMENT OF SIGNIFICANCE: Since the 1990's, numerical models developed to investigate fluid flow in bone submicrometric porous network are based on the flow induced by matrix deformation. Bone fluid flow is known to be involved in cells stimulation and hence directly influences bone remodeling. Different studies have shown that intramedullary pressure is also associated with bone mechanosensitive adaptation. This pressure is developed in bone due to blood circulation and is increased during loading or muscle stimulation. The current article reviews the studies investigating the influence of this pressure on bone porous fluid flow. They show that fluid flow is involved by this pressure even without bone matrix deformation. The current review article highlights the severe lack of studies about this mechanism.
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Affiliation(s)
- Cassandra Fernandes Da Costa
- UMR CNRS 5615, Laboratoire des Multimatériaux et Interfaces, Université de Lyon, Université Claude Bernard Lyon 1, Lyon 69372 CEDEX 08, France; CNRS, INSA Lyon, MATEIS, UMR5510, Université de Lyon, Université Claude Bernard Lyon 1, 7 avenue Jean Capelle, Villeurbanne CEDEX 69621, France
| | - Nina Attik
- UMR CNRS 5615, Laboratoire des Multimatériaux et Interfaces, Université de Lyon, Université Claude Bernard Lyon 1, Lyon 69372 CEDEX 08, France; Faculté d'Odontologie, Université de Lyon, Université Claude Bernard Lyon 1, Lyon 69372 CEDEX 08, France.
| | - Remy Gauthier
- CNRS, INSA Lyon, MATEIS, UMR5510, Université de Lyon, Université Claude Bernard Lyon 1, 7 avenue Jean Capelle, Villeurbanne CEDEX 69621, France.
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Young SAE, Heller AD, Garske DS, Rummler M, Qian V, Ellinghaus A, Duda GN, Willie BM, Grüneboom A, Cipitria A. From breast cancer cell homing to the onset of early bone metastasis: The role of bone (re)modeling in early lesion formation. SCIENCE ADVANCES 2024; 10:eadj0975. [PMID: 38381833 PMCID: PMC10881061 DOI: 10.1126/sciadv.adj0975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 01/18/2024] [Indexed: 02/23/2024]
Abstract
Breast cancer often metastasizes to bone, causing osteolytic lesions. Structural and biophysical changes are rarely studied yet are hypothesized to influence metastasis. We developed a mouse model of early bone metastasis and multimodal imaging to quantify cancer cell homing, bone (re)modeling, and onset of metastasis. Using tissue clearing and three-dimensional (3D) light sheet fluorescence microscopy, we located enhanced green fluorescent protein-positive cancer cells and small clusters in intact bones and quantified their size and spatial distribution. We detected early bone lesions using in vivo microcomputed tomography (microCT)-based time-lapse morphometry and revealed altered bone (re)modeling in the absence of detectable lesions. With a new microCT image analysis tool, we tracked the growth of early lesions over time. We showed that cancer cells home in all bone compartments, while osteolytic lesions are only detected in the metaphysis, a region of high (re)modeling. Our study suggests that higher rates of (re)modeling act as a driver of lesion formation during early metastasis.
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Affiliation(s)
- Sarah A. E. Young
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Anna-Dorothea Heller
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Daniela S. Garske
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Maximilian Rummler
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Research Centre, Shriners Hospital for Children–Canada, Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, Canada
| | - Victoria Qian
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | - Agnes Ellinghaus
- Julius Wolff Institute, Berlin Institute of Health at Charité–Universitätsmedizin Berlin, Germany
| | - Georg N. Duda
- Julius Wolff Institute, Berlin Institute of Health at Charité–Universitätsmedizin Berlin, Germany
| | - Bettina M. Willie
- Research Centre, Shriners Hospital for Children–Canada, Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, Canada
| | - Anika Grüneboom
- Leibniz-Institute for Advancing Analytics – ISAS – e.V., Dortmund, Germany
| | - Amaia Cipitria
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Group of Bioengineering in Regeneration and Cancer, Biodonostia Health Research Institute, San Sebastian, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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Bolger MW, Tekkey T, Kohn DH. Peripheral canalicular branching is decreased in streptozotocin-induced diabetes and correlates with decreased whole-bone ultimate load and perilacunar elastic work. JBMR Plus 2024; 8:ziad017. [PMID: 38505218 PMCID: PMC10945723 DOI: 10.1093/jbmrpl/ziad017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 12/01/2023] [Accepted: 12/06/2023] [Indexed: 03/21/2024] Open
Abstract
Osteocytes, the most abundant cell type in bone, play a crucial role in mechanosensation and signaling for bone formation and resorption. These cells reside within a complex lacuno-canalicular network (OLCN). Osteocyte signaling is reduced under diabetic conditions, and both type 1 and type 2 diabetes lead to reduced bone turnover, perturbed bone composition, and increased fracture risk. We hypothesized that this reduced bone turnover, and altered bone composition with diabetes is associated with reduced OLCN architecture and connectivity. This study aimed to elucidate: (1) the sequence of OLCN changes with diabetes related to bone turnover and (2) whether changes to the OLCN are associated with tissue composition and mechanical properties. Twelve- to fourteen-week-old male C57BL/6 mice were administered streptozotocin at 50 mg/kg for 5 consecutive days to induce hyperglycemia, sacrificed at baseline (BL), or after being diabetic for 3 (D3) and 7 (D7) wk with age-matched (C3, C7) controls (n = 10-12 per group). Mineralized femoral sections were infiltrated with rhodamine, imaged with confocal microscopy, then the OLCN morphology and topology were characterized and correlated against bone histomorphometry, as well as local and whole-bone mechanics and composition. D7 mice exhibited a lower number of peripheral branches relative to C7. The total number of canalicular intersections (nodes) was lower in D3 and D7 relative to BL (P < 0.05 for all), and a reduced bone formation rate (BFR) was observed at D7 vs C7. The number of nodes explained only 15% of BFR, but 45% of Ct.BV/TV, and 31% of ultimate load. The number of branches explained 30% and 22% of the elastic work at the perilacunar and intracortical region, respectively. Collectively, the reduction in OLCN architecture and association of OLCN measures with bone turnover, mechanics, and composition highlights the relevance of the osteocyte and the OLCN and a potential therapeutic target for treating diabetic skeletal fragility.
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Affiliation(s)
- Morgan W Bolger
- Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI 48109, United States
| | - Tara Tekkey
- Department of Chemistry, College of Literature, Science and the Arts, University of Michigan, Ann Arbor, MI 48109, United States
| | - David H Kohn
- Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI 48109, United States
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, United States
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Niroobakhsh M, Laughrey LE, Dallas SL, Johnson ML, Ganesh T. Computational modeling based on confocal imaging predicts changes in osteocyte and dendrite shear stress due to canalicular loss with aging. Biomech Model Mechanobiol 2024; 23:129-143. [PMID: 37642807 DOI: 10.1007/s10237-023-01763-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 08/09/2023] [Indexed: 08/31/2023]
Abstract
Exercise and physical activity exert mechanical loading on the bones which induces bone formation. However, the relationship between the osteocyte lacunar-canalicular morphology and mechanical stress experienced locally by osteocytes transducing signals for bone formation is not fully understood. In this study, we used computational modeling to predict the effect of canalicular density, the number of fluid inlets, and load direction on fluid flow shear stress (FFSS) and bone strains and how these might change following the microstructural deterioration of the lacunar-canalicular network that occurs with aging. Four distinct computational models were initially generated of osteocytes with either ten or eighteen dendrites using a fluid-structure interaction method with idealized geometries. Next, a young and a simulated aged osteocyte were developed from confocal images after FITC staining of the femur of a 4-month-old C57BL/6 mouse to estimate FFSS using a computational fluid dynamics approach. The models predicted higher fluid velocities in the canaliculi versus the lacunae. Comparison of idealized models with five versus one fluid inlet indicated that with four more inlets, one-half of the dendrites experienced FFSS greater than 0.8 Pa, which has been associated with osteogenic responses. Confocal image-based models of real osteocytes indicated a six times higher ratio of canalicular to lacunar surface area in the young osteocyte model than the simulated aged model and the average FFSS in the young model (FFSS = 0.46 Pa) was three times greater than the aged model (FFSS = 0.15 Pa). Interestingly, the surface area with FFSS values above 0.8 Pa was 23 times greater in the young versus the simulated aged model. These findings may explain the impaired mechano-responsiveness of osteocytes with aging.
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Affiliation(s)
- Mohammad Niroobakhsh
- Division of Natural and Built Environment, School of Science and Engineering, University of Missouri-Kansas City, 350 L Flarsheim Hall, 5100 Rockhill Road, Kansas City, MO, 64110, USA
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, 620 E 25th Street, Kansas City, MO, 64108, USA
| | - Loretta E Laughrey
- Division of Natural and Built Environment, School of Science and Engineering, University of Missouri-Kansas City, 350 L Flarsheim Hall, 5100 Rockhill Road, Kansas City, MO, 64110, USA
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, 620 E 25th Street, Kansas City, MO, 64108, USA
| | - Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, 620 E 25th Street, Kansas City, MO, 64108, USA
| | - Mark L Johnson
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, 620 E 25th Street, Kansas City, MO, 64108, USA
| | - Thiagarajan Ganesh
- Division of Natural and Built Environment, School of Science and Engineering, University of Missouri-Kansas City, 350 L Flarsheim Hall, 5100 Rockhill Road, Kansas City, MO, 64110, USA.
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Silveira A, Greving I, Longo E, Scheel M, Weitkamp T, Fleck C, Shahar R, Zaslansky P. Deep learning to overcome Zernike phase-contrast nanoCT artifacts for automated micro-nano porosity segmentation in bone. JOURNAL OF SYNCHROTRON RADIATION 2024; 31:136-149. [PMID: 38095668 PMCID: PMC10833422 DOI: 10.1107/s1600577523009852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 11/13/2023] [Indexed: 01/09/2024]
Abstract
Bone material contains a hierarchical network of micro- and nano-cavities and channels, known as the lacuna-canalicular network (LCN), that is thought to play an important role in mechanobiology and turnover. The LCN comprises micrometer-sized lacunae, voids that house osteocytes, and submicrometer-sized canaliculi that connect bone cells. Characterization of this network in three dimensions is crucial for many bone studies. To quantify X-ray Zernike phase-contrast nanotomography data, deep learning is used to isolate and assess porosity in artifact-laden tomographies of zebrafish bones. A technical solution is proposed to overcome the halo and shade-off domains in order to reliably obtain the distribution and morphology of the LCN in the tomographic data. Convolutional neural network (CNN) models are utilized with increasing numbers of images, repeatedly validated by `error loss' and `accuracy' metrics. U-Net and Sensor3D CNN models were trained on data obtained from two different synchrotron Zernike phase-contrast transmission X-ray microscopes, the ANATOMIX beamline at SOLEIL (Paris, France) and the P05 beamline at PETRA III (Hamburg, Germany). The Sensor3D CNN model with a smaller batch size of 32 and a training data size of 70 images showed the best performance (accuracy 0.983 and error loss 0.032). The analysis procedures, validated by comparison with human-identified ground-truth images, correctly identified the voids within the bone matrix. This proposed approach may have further application to classify structures in volumetric images that contain non-linear artifacts that degrade image quality and hinder feature identification.
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Affiliation(s)
- Andreia Silveira
- Department for Restorative, Preventive and Pediatric Dentistry, Charité-Universitaetsmedizin, Berlin, Germany
| | - Imke Greving
- Institute of Materials Physics, Helmholtz-Zentrum Hereon, Geesthacht, Germany
| | - Elena Longo
- Elettra – Sincrotrone Trieste SCpA, Basovizza, Trieste, Italy
| | | | | | - Claudia Fleck
- Fachgebiet Werkstofftechnik / Chair of Materials Science and Engineering, Institute of Materials Science and Technology, Faculty III Process Sciences, Technische Universität Berlin, Berlin, Germany
| | - Ron Shahar
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environmental Sciences, Hebrew University of Jerusalem, Rehovot, Israel
| | - Paul Zaslansky
- Department for Restorative, Preventive and Pediatric Dentistry, Charité-Universitaetsmedizin, Berlin, Germany
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Seddiqi H, Klein-Nulend J, Jin J. Osteocyte Mechanotransduction in Orthodontic Tooth Movement. Curr Osteoporos Rep 2023; 21:731-742. [PMID: 37792246 PMCID: PMC10724326 DOI: 10.1007/s11914-023-00826-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/22/2023] [Indexed: 10/05/2023]
Abstract
PURPOSE OF REVIEW Orthodontic tooth movement is characterized by periodontal tissue responses to mechanical loading, leading to clinically relevant functional adaptation of jaw bone. Since osteocytes are significant in mechanotransduction and orchestrate osteoclast and osteoblast activity, they likely play a central role in orthodontic tooth movement. In this review, we attempt to shed light on the impact and role of osteocyte mechanotransduction during orthodontic tooth movement. RECENT FINDINGS Mechanically loaded osteocytes produce signaling molecules, e.g., bone morphogenetic proteins, Wnts, prostaglandins, osteopontin, nitric oxide, sclerostin, and RANKL, which modulate the recruitment, differentiation, and activity of osteoblasts and osteoclasts. The major signaling pathways activated by mechanical loading in osteocytes are the wingless-related integration site (Wnt)/β-catenin and RANKL pathways, which are key regulators of bone metabolism. Moreover, osteocytes are capable of orchestrating bone adaptation during orthodontic tooth movement. A better understanding of the role of osteocyte mechanotransduction is crucial to advance orthodontic treatment. The optimal force level on the periodontal tissues for orthodontic tooth movement producing an adequate biological response, is debated. This review emphasizes that both mechanoresponses and inflammation are essential for achieving tooth movement clinically. To fully comprehend the role of osteocyte mechanotransduction in orthodontic tooth movement, more knowledge is needed of the biological pathways involved. This will contribute to optimization of orthodontic treatment and enhance patient outcomes.
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Affiliation(s)
- Hadi Seddiqi
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam Movement Sciences, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Jenneke Klein-Nulend
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam Movement Sciences, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Jianfeng Jin
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam Movement Sciences, University of Amsterdam and Vrije Universiteit Amsterdam, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
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Shrivas NV, Badhyal S, Tiwari AK, Mishra A, Tripathi D, Patil S. Computation of physiological loading induced interstitial fluid motion in muscle standardized femur: Healthy vs. osteoporotic bone. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 237:107592. [PMID: 37209515 DOI: 10.1016/j.cmpb.2023.107592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/06/2023] [Accepted: 05/08/2023] [Indexed: 05/22/2023]
Abstract
BACKGROUND AND OBJECTIVES Physiological loading-induced mechanical environments regulate bone modeling and remodeling. Thus, loading-induced normal strain is typically considered a stimulus to osteogenesis. However, several studies noticed new bone formation near the sites of minimal normal strain, e.g., the neutral axis of bending in long bones, which raises a question on how bone mass is maintained near these sites. Secondary mechanical components such as shear strain and interstitial fluid flow also stimulate bone cells and regulate bone mass. However, the osteogenic potential of these components is not well established. Accordingly, the present study estimates the distribution of physiological muscle loading-induced mechanical environments such as normal strain, shear strain, pore pressure, and interstitial fluid flow in long bones. METHODS A poroelastic finite element muscle standardized femur (MuscleSF) model is developed to compute the distribution of the mechanical environment as a function of bone porosities associated with osteoporotic and disuse bone loss. RESULTS The results indicate the presence of higher shear strain and interstitial fluid motion near the minimal strain sites, i.e., the neutral axis of bending of femoral cross-sections. This suggests that secondary stimuli may maintain the bone mass at these locations. Pore pressure and interstitial fluid motion reduce with the increased porosity associated with bone disorders, possibly resulting in diminished skeletal mechano-sensitivity to exogenous loading. CONCLUSIONS These outcomes present a better understanding of mechanical environment-mediated regulation of site-specific bone mass, which can be beneficial in developing prophylactic exercise to prevent bone loss in osteoporosis and muscle disuse.
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Affiliation(s)
- Nikhil Vivek Shrivas
- Department of Mechanical Engineering, Manipal University Jaipur, Jaipur, Rajasthan 303007, India; Department of Mechatronics Engineering, Manipal University Jaipur, Jaipur, Rajasthan 303007, India
| | - Subham Badhyal
- Bubba Watson and PING Golf Motion Analysis Laboratory, Herbert J Louis Center for Pediatric Orthopedics, Phoenix Children...s Hospital, Phoenix, Arizona, 85016, USA
| | - Abhishek Kumar Tiwari
- Department of Applied Mechanics, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, Uttar Pradesh 211004, India
| | - Ashutosh Mishra
- Department of Applied Mechanics, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, Uttar Pradesh 211004, India
| | - Dharmendra Tripathi
- Department of Mathematics, National Institute of Technology Uttarakhand, Srinagar, Uttarakhand 246174, India.
| | - Santosh Patil
- Department of Mechanical Engineering, Manipal University Jaipur, Jaipur, Rajasthan 303007, India
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Blouin S, Misof BM, Mähr M, Fratzl-Zelman N, Roschger P, Lueger S, Messmer P, Keplinger P, Rauch F, Glorieux FH, Berzlanovich A, Gruber GM, Brugger PC, Shane E, Recker RR, Zwerina J, Hartmann MA. Osteocyte lacunae in transiliac bone biopsy samples across life span. Acta Biomater 2023; 157:275-287. [PMID: 36549635 DOI: 10.1016/j.actbio.2022.11.051] [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: 08/01/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/23/2022]
Abstract
Osteocytes act as bone mechanosensors, regulators of osteoblast/osteoclast activity and mineral homeostasis, however, knowledge about their functional/morphological changes throughout life is limited. We used quantitative backscattered electron imaging (qBEI) to investigate osteocyte lacunae sections (OLS) as a 2D-surrogate characterizing the osteocytes. OLS characteristics, the density of mineralized osteocyte lacunae (i.e., micropetrotic osteocytes, md.OLS-Density in nb/mm2) and the average degree of mineralization (CaMean in weight% calcium) of cortex and spongiosa were analyzed in transiliac biopsy samples from healthy individuals under 30 (n=59) and over 30 years (n=50) (i.e., before and after the age of peak bone mass, respectively). We found several differences in OLS-characteristics: 1). Inter-individually between the age groups: OLS-Density and OLS-Porosity were reduced by about 20% in older individuals in spongiosa and in cortex versus younger probands (both, p < 0.001). 2). Intra-individually between bone compartments: OLS-Density was higher in the cortex, +18.4%, p < 0.001 for younger and +7.6%, p < 0.05 for older individuals. Strikingly, the most frequent OLS nearest-neighbor distance was about 30 µm in both age groups and at both bone sites revealing a preferential organization of osteocytes in clusters. OLS-Density was negatively correlated with CaMean in both spongiosa and cortex (both, p < 0.001). Few mineralized OLS were found in young individuals along with an increase of md.OLS-Density with age. In summary, this transiliac bone sample analysis of 200000 OLS from 109 healthy individuals throughout lifespan reveals several age-related differences in OLS characteristics. Moreover, our study provides reference data from healthy individuals for different ages to be used for diagnosis of bone abnormalities in diseases. STATEMENT OF SIGNIFICANCE: Osteocytes are bone cells embedded in lacunae within the mineralized bone matrix and have a key role in the bone metabolism and the mineral homeostasis. Not easily accessible, we used quantitative backscattered electron imaging to determine precisely number and shape descriptors of the osteocyte lacunae in 2D. We analyzed transiliac biopsy samples from 109 individuals with age distributed from 2 to 95 years. Compact cortical bone showed constantly higher lacunar density than cancellous bone but the lacunar density in both bone tissue decreased with age before the peak bone mass age at 30 years and stabilized or even increased after this age. This extensive study provides osteocyte lacunae reference data from healthy individuals usable for bone pathology diagnosis.
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Affiliation(s)
- Stéphane Blouin
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria & Vienna Bone and Growth Center, Vienna, Austria.
| | - Barbara M Misof
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria & Vienna Bone and Growth Center, Vienna, Austria
| | - Matthias Mähr
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria & Vienna Bone and Growth Center, Vienna, Austria
| | - Nadja Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria & Vienna Bone and Growth Center, Vienna, Austria
| | - Paul Roschger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria & Vienna Bone and Growth Center, Vienna, Austria
| | - Sonja Lueger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria & Vienna Bone and Growth Center, Vienna, Austria
| | - Phaedra Messmer
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria & Vienna Bone and Growth Center, Vienna, Austria
| | - Petra Keplinger
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria & Vienna Bone and Growth Center, Vienna, Austria
| | - Frank Rauch
- Shriners Hospital for Children and McGill University, Montreal, ON QC, H4A 0A9, Canada
| | - Francis H Glorieux
- Shriners Hospital for Children and McGill University, Montreal, ON QC, H4A 0A9, Canada
| | - Andrea Berzlanovich
- Unit of Forensic Gerontology, Center of Forensic Medicine, Medical University of Vienna, Vienna, Austria
| | - Gerlinde M Gruber
- Department of Anatomy and Biomechanics, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Peter C Brugger
- Center for Anatomy and Cell Biology, Department of Anatomy, Medical University of Vienna, Vienna, Austria
| | - Elizabeth Shane
- Department of Medicine, Division of Endocrinology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Robert R Recker
- Osteoporosis Research Center, Creighton University, Omaha, Nebraska, USA
| | - Jochen Zwerina
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria & Vienna Bone and Growth Center, Vienna, Austria
| | - Markus A Hartmann
- Ludwig Boltzmann Institute of Osteology at the Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Medical Department Hanusch Hospital, Vienna, Austria & Vienna Bone and Growth Center, Vienna, Austria
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9
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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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Irandoust S, Müftü S. On computational predictions of fluid flow and its effects on bone healing in dental implant treatments: an investigation of spatiotemporal fluid flow in cyclic loading. Biomech Model Mechanobiol 2023; 22:85-104. [PMID: 36329356 DOI: 10.1007/s10237-022-01633-x] [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: 03/21/2022] [Accepted: 09/05/2022] [Indexed: 11/06/2022]
Abstract
Fluid flow in (porous) bone plays an important role in its maintenance, adaptation, and healing after an injury. Experimental and computational studies apply mechanical loading on bone to predict fluid flow development and/or to find its material properties. In most cases, mechanical loading is applied as a linear function in time. Multiple loading functions-with identical peak load and loading frequency-were used to investigate load-induced fluid flow and predict bone healing surrounding a dental implant. Implementing an instantaneous healing stimulus led to major differences in healing predictions for slightly different loading functions. Load-induced fluid flow was found to be displacement-rate dependent with complex spatial-temporal variations and not necessarily symmetrical during loading and unloading phases. Haversine loading resulted in more numerical stability compared to ramped/triangular loading, providing the opportunity for further investigation of the effects of various physiological masticatory loadings. It was concluded that using the average healing stimulus during cyclic loading gives the most robust bone healing predictions.
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Affiliation(s)
- Soroush Irandoust
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, 02115, USA.
| | - Sinan Müftü
- Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, 02115, USA
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11
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Smotrova E, Li S, Silberschmidt VV. Mechanoregulated trabecular bone adaptation: Progress report on in silico approaches. BIOMATERIALS AND BIOSYSTEMS 2022; 7:100058. [PMID: 36824485 PMCID: PMC9934474 DOI: 10.1016/j.bbiosy.2022.100058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 06/28/2022] [Accepted: 07/14/2022] [Indexed: 10/17/2022] Open
Abstract
Adaptation is the process by which bone responds to changes in loading environment and modulates its properties and spatial organization to meet the mechanical demands. Adaptation in trabecular bone is achieved through increase in bone mass and alignment of trabecular-bone morphology along the loading direction. This transformation of internal microstructure is governed by mechanical stimuli sensed by mechanosensory cells in the bone matrix. Realisation of adaptation in the form of local bone-resorption and -formation activities as a function of mechanical stimuli is still debated. In silico modelling is a useful tool for simulation of various scenarios that cannot be investigated in vivo and particularly well suited for prediction of trabecular bone adaptation. This progress report presents the recent advances in in silico modelling of mechanoregulated adaptation at the scale of trabecular bone tissue. Four well-established bone-adaptation models are reviewed in terms of their recent improvements and validation. They consider various mechanical factors: (i) strain energy density, (ii) strain and damage, (iii) stress nonuniformity and (iv) daily stress. Contradictions of these models are discussed and their ability to describe adequately a real-life mechanoregulation process in bone is compared.
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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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Rayat Pisheh H, Ansari M, Eslami H. How is mechanobiology involved in bone regenerative medicine? Tissue Cell 2022; 76:101821. [DOI: 10.1016/j.tice.2022.101821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/27/2022] [Accepted: 05/10/2022] [Indexed: 10/18/2022]
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Effects of Osteocyte Shape on Fluid Flow and Fluid Shear Stress of the Loaded Bone. BIOMED RESEARCH INTERNATIONAL 2022; 2022:3935803. [PMID: 35677099 PMCID: PMC9170394 DOI: 10.1155/2022/3935803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 04/19/2022] [Indexed: 11/17/2022]
Abstract
This study was conducted to better understand the specific behavior of the intraosseous fluid flow. We calculated the number and distribution of bone canaliculi around the osteocytes based on the varying shapes of osteocytes. We then used these calculated parameters and other bone microstructure data to estimate the anisotropy permeability of the lacunar-canalicular network. Poroelastic finite element models of the osteon were established, and the influence of the osteocyte shape on the fluid flow properties of osteons under an axial displacement load was analyzed. Two types of boundary conditions (BC) that might occur in physiological environments were considered on the cement line of the osteon. BC1 allows free fluid passage from the outer elastic restraint boundary, and BC2 is impermeable and allows no free fluid passage from outer displacement constrained boundary. They both have the same inner boundary conditions that allow fluid to pass through. Changes in the osteocyte shape altered the maximum value of pressure gradient (PG), pore pressure (PP), fluid velocity (FV), and fluid shear stress (FSS) relative to the reference model (spherical osteocytes). The maximum PG, PP, FV, and FSS in BC2 were nearly 100% larger than those in BC1, respectively. It is found that the BC1 was closer to the real physiological environment. The fluid flow along different directions in the elongated osteocyte model was more evident than that in other models, which may have been due to the large difference in permeability along different directions. Changes in osteocyte shape significantly affect the degrees of anisotropy of fluid flow and porous media of the osteon. The model presented in this study can accurately quantify fluid flow in the lacunar-canalicular network.
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15
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Murshid SA. Bone permeability and mechanotransduction: Some current insights into the function of the lacunar-canalicular network. Tissue Cell 2022; 75:101730. [PMID: 35032785 DOI: 10.1016/j.tice.2022.101730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 10/19/2022]
Abstract
Lacunar-canalicular (LC) permeability involves the passage of fluids, nutrients, oxygen, ions, and signalling molecules through bone tissue, facilitating the maintenance of bone vitality and function and responses to various physiological conditions and diseases. LC permeability and fluid flow-shear stress/drag force play important roles in mechanotransduction in bone tissue by inducing mechanical stimuli in osteocytes, modulating cellular functions, and determining bone adaptation. Alterations in LC structure may therefore influence the fluid flow pattern through the LC network, thereby affecting the ability of osteocytes to sense and translate mechanical signals and possibly contributing to bone remodelling. Several bone-health conditions are associated with changes in LC structure and function and may affect mechanotransduction and responses, although the mechanisms underlying these associations are still not fully understood. In this review, recent studies of LC networks, their formation and transfer mechanical stimuli, and changes in structure, functional permeability, and mechanotransduction that result from age, pathology, and mechanical loading are discussed. Additionally, applications of vibration and low-intensity pulsed ultrasound in bone healthcare and regeneration fields are also presented.
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Affiliation(s)
- Sakhr Ahmed Murshid
- Institute for Globally Distributed Open Research and Education (IGDORE); Ilmajoki Health Public Dental Clinics, Social and Health Care Services in Jalasjärvi, Ilmajoki, Kurikka, Finland.
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16
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Abstract
PURPOSE OF REVIEW Osteocytes are the conductors of bone adaptation and remodelling. Buried inside the calcified matrix, they sense mechanical cues and signal osteoclasts in case of low activity, and osteoblasts when stresses are high. How do osteocytes detect mechanical stress? What physical signal do they perceive? Finite element analysis is a useful tool to address these questions as it allows calculating stresses, strains and fluid flow where they cannot be measured. The purpose of this review is to evaluate the capabilities and challenges of finite element models of bone, in particular the osteocytes and load-induced activation mechanisms. RECENT FINDINGS High-resolution imaging and increased computational power allow ever more detailed modelling of osteocytes, either in isolation or embedded within the mineralised matrix. Over the years, homogeneous models of bone and osteocytes got replaced by heterogeneous and microstructural models, including, e.g. the lacuno-canalicular network and the cytoskeleton. The lacuno-canalicular network induces strain amplifications and the osteocyte protrusions seem to be stimulated much more than the cell body, both by strain and fluid flow. More realistic cell geometries, like minute constrictions of the canaliculi, increase this effect. Microstructural osteocyte models describe the transduction of external stimuli to the nucleus. Supracellular multiscale models (e.g. of a tunnelling osteon) allow to study differential loading of osteocytes and to distinguish between strain and fluid flow as the pivotal stimulatory cue. In the future, the finite element models may be enhanced by including chemical transport and intercellular communication between osteocytes, osteoclasts and osteoblasts.
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Affiliation(s)
- Theodoor H Smit
- Department of Medical Biology, Amsterdam University Medical Centres, University of Amsterdam, Amsterdam, The Netherlands.
- Department of Orthopaedic Surgery, Amsterdam Movement Sciences Research Institute, Amsterdam, The Netherlands.
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17
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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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18
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Lepcio P, Svatík J, Režnáková E, Zicha D, Lesser A, Ondreas F. Anisotropic solid-state PLA foaming templated by crystal phase pre-oriented with 3D printing: Cell supporting structures with directional capillary transfer function. J Mater Chem B 2022; 10:2889-2898. [DOI: 10.1039/d1tb02133h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bones represent a superb biomaterial that combines high mechanical stiffness with nutrition delivery to its osteocyte cells through the microscopical Haversian canals and bone canaliculi. Such structure is hard to...
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19
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Bortel E, Grover LM, Eisenstein N, Seim C, Suhonen H, Pacureanu A, Westenberger P, Raum K, Langer M, Peyrin F, Addison O, Hesse B. Interconnectivity Explains High Canalicular Network Robustness between Neighboring Osteocyte Lacunae in Human Bone. ADVANCED NANOBIOMED RESEARCH 2021. [DOI: 10.1002/anbr.202100090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Emely Bortel
- Xploraytion GmbH Bismarckstrasse 10-12 10625 Berlin Germany
| | - Liam M Grover
- School of Chemical Engineering University of Birmingham B15 2TT Birmingham UK
| | - Neil Eisenstein
- School of Chemical Engineering University of Birmingham B15 2TT Birmingham UK
| | - Christian Seim
- Xploraytion GmbH Bismarckstrasse 10-12 10625 Berlin Germany
- Technical University of Berlin: Institute of Optics and Atomic Physics 10623 Berlin Germany
| | - Heikki Suhonen
- University of Helsinki: Department of Physics 00560 Helsinki Finland
| | | | | | - Kay Raum
- Charité—Universitätsmedizin Berlin Corporate Member of Freie Universität Berlin Humboldt-Universität zu Berlinand Berlin Institute of Health BCRT—Berlin Institute of Health Center for Regenerative Therapies 13353 Berlin Germany
| | - Max Langer
- Univ Lyon CNRS 5220Inserm U1294INSA Lyon 69621 Creatis Villeurbanne Cedex France
- Université Grenoble Alpes CNRSUMR 5525 VetAgro SupGrenoble INPTIMC F-38000 Grenoble France
| | - Francoise Peyrin
- ESRF: Experiment Division 38000 Grenoble France
- Univ Lyon CNRS 5220Inserm U1294INSA Lyon 69621 Creatis Villeurbanne Cedex France
| | - Owen Addison
- Faculty of Dentistry Oral and Craniofacial Sciences Kings College SE1 9RT London UK
| | - Bernhard Hesse
- Xploraytion GmbH Bismarckstrasse 10-12 10625 Berlin Germany
- ESRF: Experiment Division 38000 Grenoble France
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20
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García-Aznar JM, Nasello G, Hervas-Raluy S, Pérez MÁ, Gómez-Benito MJ. Multiscale modeling of bone tissue mechanobiology. Bone 2021; 151:116032. [PMID: 34118446 DOI: 10.1016/j.bone.2021.116032] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/25/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023]
Abstract
Mechanical environment has a crucial role in our organism at the different levels, ranging from cells to tissues and our own organs. This regulatory role is especially relevant for bones, given their importance as load-transmitting elements that allow the movement of our body as well as the protection of vital organs from load impacts. Therefore bone, as living tissue, is continuously adapting its properties, shape and repairing itself, being the mechanical loads one of the main regulatory stimuli that modulate this adaptive behavior. Here we review some key results of bone mechanobiology from computational models, describing the effect that changes associated to the mechanical environment induce in bone response, implant design and scaffold-driven bone regeneration.
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Affiliation(s)
- José Manuel García-Aznar
- Multiscale in Mechanical and Biological Engineering, Instituto de Investigación en Ingeniería de Aragón (I3A), Instituto de Investigación Sanitaria Aragón (IIS Aragón), University of Zaragoza, Zaragoza, Spain.
| | - Gabriele Nasello
- Multiscale in Mechanical and Biological Engineering, Instituto de Investigación en Ingeniería de Aragón (I3A), Instituto de Investigación Sanitaria Aragón (IIS Aragón), University of Zaragoza, Zaragoza, Spain; Biomechanics Section, KU Leuven, Leuven, Belgium
| | - Silvia Hervas-Raluy
- Multiscale in Mechanical and Biological Engineering, Instituto de Investigación en Ingeniería de Aragón (I3A), Instituto de Investigación Sanitaria Aragón (IIS Aragón), University of Zaragoza, Zaragoza, Spain
| | - María Ángeles Pérez
- Multiscale in Mechanical and Biological Engineering, Instituto de Investigación en Ingeniería de Aragón (I3A), Instituto de Investigación Sanitaria Aragón (IIS Aragón), University of Zaragoza, Zaragoza, Spain
| | - María José Gómez-Benito
- Multiscale in Mechanical and Biological Engineering, Instituto de Investigación en Ingeniería de Aragón (I3A), Instituto de Investigación Sanitaria Aragón (IIS Aragón), University of Zaragoza, Zaragoza, Spain
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21
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Yokoyama Y, Kameo Y, Kamioka H, Adachi T. High-resolution image-based simulation reveals membrane strain concentration on osteocyte processes caused by tethering elements. Biomech Model Mechanobiol 2021; 20:2353-2360. [PMID: 34471950 PMCID: PMC8595188 DOI: 10.1007/s10237-021-01511-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 08/13/2021] [Indexed: 11/08/2022]
Abstract
Osteocytes are vital for regulating bone remodeling by sensing the flow-induced mechanical stimuli applied to their cell processes. In this mechanosensing mechanism, tethering elements (TEs) connecting the osteocyte process with the canalicular wall potentially amplify the strain on the osteocyte processes. The ultrastructure of the osteocyte processes and canaliculi can be visualized at a nanometer scale using high-resolution imaging via ultra-high voltage electron microscopy (UHVEM). Moreover, the irregular shapes of the osteocyte processes and the canaliculi, including the TEs in the canalicular space, should considerably influence the mechanical stimuli applied to the osteocytes. This study aims to characterize the roles of the ultrastructure of osteocyte processes and canaliculi in the mechanism of osteocyte mechanosensing. Thus, we constructed a high-resolution image-based model of an osteocyte process and a canaliculus using UHVEM tomography and investigated the distribution and magnitude of flow-induced local strain on the osteocyte process by performing fluid–structure interaction simulation. The analysis results reveal that local strain concentration in the osteocyte process was induced by a small number of TEs with high tension, which were inclined depending on the irregular shapes of osteocyte processes and canaliculi. Therefore, this study could provide meaningful insights into the effect of ultrastructure of osteocyte processes and canaliculi on the osteocyte mechanosensing mechanism.
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Affiliation(s)
- Yuka Yokoyama
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Yoshitaka Kameo
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.,Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.,Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Hiroshi Kamioka
- Department of Orthodontics, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-Cho, Kita-ku, Okayama, 700-8525, Japan
| | - Taiji Adachi
- Department of Micro Engineering, Graduate School of Engineering, Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. .,Department of Biosystems Science, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. .,Department of Mammalian Regulatory Network, Graduate School of Biostudies, Kyoto University, 53 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.
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22
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Smit TH. Closing the osteon: Do osteocytes sense strain rate rather than fluid flow? Bioessays 2021; 43:e2000327. [PMID: 34111316 DOI: 10.1002/bies.202000327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 05/28/2021] [Accepted: 06/02/2021] [Indexed: 11/05/2022]
Abstract
Osteons are cylindrical structures of bone created by matrix resorbing osteoclasts, followed by osteoblasts that deposit new bone. Osteons align with the principal loading direction and it is thought that the osteoclasts are directed by osteocytes, the mechanosensitive cells that reside inside the bone matrix. These osteocytes are presumably controlled by interstitial fluid flow, induced by the physiological loading of bones. Here I consider the stimulation of osteocytes while the osteon is closed by osteoblasts. In a conceptual finite element model, bone is considered a poro-elastic material and subjected to locomotion-induced loading conditions. It appears that the magnitude of flow is constant along the closing cone, while shear strain rate in the bone matrix diminishes linearly with the deposition of bone. This suggests that shear strain rate, rather than fluid flow, is the physical cue that controls osteocytes and bone deposition in newly formed osteons.
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Affiliation(s)
- Theodoor H Smit
- Department of Medical Biology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands.,Department of Orthopaedic Surgery, Amsterdam University Medical Centers, Amsterdam Movement Sciences Research Institute, Amsterdam, The Netherlands
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23
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Yuan Y, Jagga S, Martins JS, Rana R, Pajevic PD, Liu ES. Impaired 1,25 dihydroxyvitamin D3 action and hypophosphatemia underlie the altered lacuno-canalicular remodeling observed in the Hyp mouse model of XLH. PLoS One 2021; 16:e0252348. [PMID: 34043707 PMCID: PMC8158930 DOI: 10.1371/journal.pone.0252348] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 05/12/2021] [Indexed: 11/28/2022] Open
Abstract
Osteocytes remodel the perilacunar matrix and canaliculi. X-linked hypophosphatemia (XLH) is characterized by elevated serum levels of fibroblast growth factor 23 (FGF23), leading to decreased 1,25 dihydroxyvitamin D3 (1,25D) production and hypophosphatemia. Bones from mice with XLH (Hyp) have enlarged osteocyte lacunae, enhanced osteocyte expression of genes of bone remodeling, and impaired canalicular structure. The altered lacuno-canalicular (LCN) phenotype is improved with 1,25D or anti-FGF23 antibody treatment, pointing to roles for 1,25D and/or phosphate in regulating this process. To address whether impaired 1,25D action results in LCN alterations, the LCN phenotype was characterized in mice lacking the vitamin D receptor (VDR) in osteocytes (VDRf/f;DMP1Cre+). Mice lacking the sodium phosphate transporter NPT2a (NPT2aKO) have hypophosphatemia and high serum 1,25D levels, therefore the LCN phenotype was characterized in these mice to determine if increased 1,25D compensates for hypophosphatemia in regulating LCN remodeling. Unlike Hyp mice, neither VDRf/f;DMP1Cre+ nor NPT2aKO mice have dramatic alterations in cortical microarchitecture, allowing for dissecting 1,25D and phosphate specific effects on LCN remodeling in tibial cortices. Histomorphometric analyses demonstrate that, like Hyp mice, tibiae and calvariae in VDRf/f;DMP1Cre+ and NPT2aKO mice have enlarged osteocyte lacunae (tibiae: 0.15±0.02μm2(VDRf/f;DMP1Cre-) vs 0.19±0.02μm2(VDRf/f;DMP1Cre+), 0.12±0.02μm2(WT) vs 0.18±0.0μm2(NPT2aKO), calvariae: 0.09±0.02μm2(VDRf/f;DMP1Cre-) vs 0.11±0.02μm2(VDRf/f;DMP1Cre+), 0.08±0.02μm2(WT) vs 0.13±0.02μm2(NPT2aKO), p<0.05 all comparisons) and increased immunoreactivity of bone resorption marker Cathepsin K (Ctsk). The osteocyte enriched RNA isolated from tibiae in VDRf/f;DMP1Cre+ and NPT2aKO mice have enhanced expression of matrix resorption genes that are classically expressed by osteoclasts (Ctsk, Acp5, Atp6v0d2, Nhedc2). Treatment of Ocy454 osteocytes with 1,25D or phosphate inhibits the expression of these genes. Like Hyp mice, VDRf/f;DMP1Cre+ and NPT2aKO mice have impaired canalicular organization in tibia and calvaria. These studies demonstrate that hypophosphatemia and osteocyte-specific 1,25D actions regulate LCN remodeling. Impaired 1,25D action and low phosphate levels contribute to the abnormal LCN phenotype observed in XLH.
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Affiliation(s)
- Ye Yuan
- Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Endocrinology, Diabetes, Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
| | - Supriya Jagga
- Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Endocrinology, Diabetes, Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
| | - Janaina S. Martins
- Harvard Medical School, Boston, Massachusetts, United States of America
- Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Rakshya Rana
- Division of Endocrinology, Diabetes, Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
| | - Paola Divieti Pajevic
- Department of Translational Dental Medicine, Boston University School of Dental Medicine, Boston, Massachusetts, United States of America
| | - Eva S. Liu
- Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Endocrinology, Diabetes, Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
- * E-mail:
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24
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Shrivas NV, Tiwari AK, Kumar R, Patil S, Tripathi D, Badhyal S. Physiological Loading-Induced Interstitial Fluid Dynamics in Osteon of Osteogenesis Imperfecta Bone. J Biomech Eng 2021; 143:1106937. [PMID: 33834233 DOI: 10.1115/1.4050818] [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: 07/07/2020] [Indexed: 11/08/2022]
Abstract
Osteogenesis imperfecta (OI), also known as "brittle bone disease," is a genetic bone disorder. OI bones experience frequent fractures. Surgical procedures are usually followed by clinicians in the management of OI. It has been observed physical activity is equally beneficial in reducing OI bone fractures in both children and adults as mechanical stimulation improves bone mass and strength. Loading-induced mechanical strain and interstitial fluid flow stimulate bone remodeling activities. Several studies have characterized strain environment in OI bones, whereas very few studies attempted to characterize the interstitial fluid flow. OI significantly affects bone micro-architecture. Thus, this study anticipates that canalicular fluid flow reduces in OI bone in comparison to the healthy bone in response to physiological loading due to altered poromechanical properties. This work attempts to understand the canalicular fluid distribution in single osteon models of OI and healthy bone. A poromechanical model of osteon is developed to compute pore-pressure and interstitial fluid flow as a function of gait loading pattern reported for OI and healthy subjects. Fluid distribution patterns are compared at different time-points of the stance phase of the gait cycle. It is observed that fluid flow significantly reduces in OI bone. Additionally, flow is more static than dynamic in OI osteon in comparison to healthy subjects. This work attempts to identify the plausible explanation behind the diminished mechanotransduction capability of OI bone. This work may further be extended for designing better biomechanical therapies to enhance the fluid flow in order to improve osteogenic activities in OI bone.
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Affiliation(s)
- Nikhil Vivek Shrivas
- Department of Mechanical Engineering, Manipal University Jaipur, Jaipur, Rajasthan 303007, India; Department of Mechatronics Engineering, Manipal University Jaipur, Jaipur, Rajasthan 303007, India
| | - Abhishek Kumar Tiwari
- Department of Applied Mechanics, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, Uttar Pradesh 211004, India
| | - Rakesh Kumar
- Department of Mechanical Engineering, Manipal University Jaipur, Jaipur, Rajasthan 303007, India
| | - Santosh Patil
- Department of Mechanical Engineering, Manipal University Jaipur, Jaipur, Rajasthan 303007, India
| | - Dharmendra Tripathi
- Department of Mathematics, National Institute of Technology Uttarakhand, Srinagar, Uttarakhand 246174, India
| | - Subham Badhyal
- Sports Authority of India, Jawahar Lal Nehru Stadium, Lodhi Road, New Delhi 110003, India; MYAS-GNDU Department of Sports Sciences and Medicine, Guru Nanak Dev University, Amritsar, Punjab 143005, India
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25
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Cooke KM, Mahoney P, Miszkiewicz JJ. Secondary osteon variants and remodeling in human bone. Anat Rec (Hoboken) 2021; 305:1299-1315. [PMID: 33890727 DOI: 10.1002/ar.24646] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 03/01/2021] [Accepted: 03/23/2021] [Indexed: 11/09/2022]
Abstract
Histomorphometric analysis of human cortical bone has documented the occurrence of secondary osteon variants. These include drifting osteons which form tails as they move erratically through the cortex and Type II osteons which show partial resorption and redeposition within the cement line of the osteon. Little is known about the biological significance of these variants. Prior studies suggested correlations with age, biomechanics, diet, and mineral homeostasis. No study has yet tested for osteon variant associations with static measures of bone remodeling. In this study, thin sections (n = 112) of the posterior femur representing a late English Medieval adult human osteological collection, subdivided by age, sex, and socio-economic status, were examined to determine whether remodeling indicators reconstructed from osteon parameters (area, diameter, area ratios) and densities differed between categories of presence or absence of Type II and drifting osteon variants. Of the 112 sections, 33 presented with Type II osteons, and 38 had drifting osteons. Sporadic statistically significant results were identified. Haversian canal:osteon area ratio differed (p = 0.017) with Type II osteon presence, Type II osteons were more prevalent in males than females (p = 0.048), and drifting osteons were associated with smaller osteon (p = 0.049) and Haversian canal area (p = 0.05). These results may be explained through some biological (sex) and social (status) processes such as a period of physiological recovery (e.g., following lactation, malnutrition). However, the general lack of consistent relationships between osteon variants and remodeling indicators suggests they occur as a result of natural variation.
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Affiliation(s)
- Karen M Cooke
- Skeletal Biology and Forensic Anthropology Research Group, School of Archaeology and Anthropology, Australian National University, Canberra, Australia
| | - Patrick Mahoney
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Justyna J Miszkiewicz
- Skeletal Biology and Forensic Anthropology Research Group, School of Archaeology and Anthropology, Australian National University, Canberra, Australia.,Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
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26
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Tiwari AK, Goyal A, Prasad J. Modeling cortical bone adaptation using strain gradients. Proc Inst Mech Eng H 2021; 235:636-654. [PMID: 33754910 DOI: 10.1177/09544119211000228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Cyclic and low-magnitude loading promotes osteogenesis (i.e. new bone formation). Normal strain, strain energy density and fatigue damage accumulation are typically considered as osteogenic stimuli in computer models to predict site-specific new bone formation. These models however had limited success in explaining osteogenesis near the sites of minimal normal strain, for example, neutral axis of bending. Other stimuli such as fluid motion or strain gradient also stimulate bone formation. In silico studies modeled the new bone formation as a function of fluid motion, however, computation of fluid motion involves complex mathematical calculations. Strain gradients drive fluid flow and thus can also be established as the stimulus. Osteogenic potential of strain gradients is however not well established. The present study establishes strain gradients as osteogenic stimuli. Bending-induced strain gradients are computed at cortical bone cross-sections reported in animal loading in vivo studies. Correlation analysis between strain gradients and site of osteogenesis is analyzed. In silico model is also developed to test the osteogenic potential of strain gradients. The model closely predicts in vivo new bone distribution as a function of strain gradients. The outcome establishes strain gradient as computationally easy and robust stimuli to predict site-specific osteogenesis. The present study may be useful in the development of biomechanical approaches to mitigate bone loss.
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Affiliation(s)
- Abhishek Kumar Tiwari
- Department of Applied Mechanics, Motilal Nehru National Institute of Technology Allahabad, Prayagraj, Uttar Pradesh, India
| | - Ajay Goyal
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab, India
| | - Jitendra Prasad
- Department of Mechanical Engineering, Indian Institute of Technology Ropar, Rupnagar, Punjab, India
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27
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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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28
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The mechanoresponse of bone is closely related to the osteocyte lacunocanalicular network architecture. Proc Natl Acad Sci U S A 2020; 117:32251-32259. [PMID: 33288694 PMCID: PMC7768754 DOI: 10.1073/pnas.2011504117] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The explanation of how bone senses and adapts to mechanical stimulation still relies on hypotheses. The fluid flow hypothesis claims that a load-induced fluid flow through the lacunocanalicular network can be sensed by osteocytes, which reside within the network structure. We show that considering the network architecture results in a better prediction of bone remodeling than mechanical strain alone. This was done by calculating the fluid flow through the lacunocanalicular network in bone volumes covering the complete cross-sections of mouse tibiae, which underwent controlled in vivo loading. The established relationship between mechanosensitivity and network architecture in individual animals implies possibilities for patient-specific therapies. A new connectomics approach to analyze lacunocanalicular network properties is necessary to understand skeletal mechanobiology. Organisms rely on mechanosensing mechanisms to adapt to changes in their mechanical environment. Fluid-filled network structures not only ensure efficient transport but can also be employed for mechanosensation. The lacunocanalicular network (LCN) is a fluid-filled network structure, which pervades our bones and accommodates a cell network of osteocytes. For the mechanism of mechanosensation, it was hypothesized that load-induced fluid flow results in forces that can be sensed by the cells. We use a controlled in vivo loading experiment on murine tibiae to test this hypothesis, whereby the mechanoresponse was quantified experimentally by in vivo micro-computed tomography (µCT) in terms of formed and resorbed bone volume. By imaging the LCN using confocal microscopy in bone volumes covering the entire cross-section of mouse tibiae and by calculating the fluid flow in the three-dimensional (3D) network, we could perform a direct comparison between predictions based on fluid flow velocity and the experimentally measured mechanoresponse. While local strain distributions estimated by finite-element analysis incorrectly predicts preferred bone formation on the periosteal surface, we demonstrate that additional consideration of the LCN architecture not only corrects this erroneous bias in the prediction but also explains observed differences in the mechanosensitivity between the three investigated mice. We also identified the presence of vascular channels as an important mechanism to locally reduce fluid flow. Flow velocities increased for a convergent network structure where all of the flow is channeled into fewer canaliculi. We conclude that, besides mechanical loading, LCN architecture should be considered as a key determinant of bone adaptation.
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29
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Moreno-Jiménez I, Cipitria A, Sánchez-Herrero A, van Tol AF, Roschger A, Lahr CA, McGovern JA, Hutmacher DW, Fratzl P. Human and mouse bones physiologically integrate in a humanized mouse model while maintaining species-specific ultrastructure. SCIENCE ADVANCES 2020; 6:6/44/eabb9265. [PMID: 33115741 PMCID: PMC7608795 DOI: 10.1126/sciadv.abb9265] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 08/31/2020] [Indexed: 05/07/2023]
Abstract
Humanized mouse models are increasingly studied to recapitulate human-like bone physiology. While human and mouse bone architectures differ in multiple scales, the extent to which chimeric human-mouse bone physiologically interacts and structurally integrates remains unknown. Here, we identify that humanized bone is formed by a mosaic of human and mouse collagen, structurally integrated within the same bone organ, as shown by immunohistochemistry. Combining this with materials science techniques, we investigate the extracellular matrix of specific human and mouse collagen regions. We show that human-like osteocyte lacunar-canalicular network is retained within human collagen regions and is distinct to that of mouse tissue. This multiscale analysis shows that human and mouse tissues physiologically integrate into a single, functional bone tissue while maintaining their species-specific ultrastructural differences. These results offer an original method to validate and advance tissue-engineered human-like bone in chimeric animal models, which grow to be eloquent tools in biomedical research.
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Affiliation(s)
- I Moreno-Jiménez
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - A Cipitria
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - A Sánchez-Herrero
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - A F van Tol
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - A Roschger
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany
| | - C A Lahr
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - J A McGovern
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - D W Hutmacher
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany.
- Institute of Health Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - P Fratzl
- Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, Potsdam, Germany.
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30
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Dallas SL, Moore DS. Using confocal imaging approaches to understand the structure and function of osteocytes and the lacunocanalicular network. Bone 2020; 138:115463. [PMID: 32512167 PMCID: PMC7423610 DOI: 10.1016/j.bone.2020.115463] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 05/29/2020] [Indexed: 02/07/2023]
Abstract
Although overlooked in the past, osteocytes have come to the forefront of skeletal biology and are now recognized as a key cell type that integrates hormonal, mechanical and other signals to control bone mass through regulation of both osteoblast and osteoclast activity. With the surge of recent interest in osteocytes as bone regulatory cells and the discovery that they also function as endocrine regulators of phosphate homeostasis, there has been renewed interest in understanding the structure and function of these unique and relatively inaccessible cells. Osteocytes are embedded within the mineralized bone matrix and are housed within a complex lacunocanalicular system which connects them with the circulation and with other organ systems. This has presented unique challenges for imaging these cells. This review summarizes recent advances in confocal imaging approaches for visualizing osteocytes and their lacunocanalicular networks in both living and fixed bone specimens and discusses how computational approaches can be combined with live and fixed cell imaging techniques to generate quantitative outputs and predictive models. The integration of advanced imaging with computational approaches promises to lead to a more in depth understanding of the structure and function of osteocyte networks and the lacunocanalicular system in the healthy and aging state as well as in pathological conditions in bone.
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Affiliation(s)
- Sarah L Dallas
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO 64108, United States of America.
| | - David S Moore
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, Kansas City, MO 64108, United States of America
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31
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Signalling molecule transport analysis in lacunar-canalicular system. Biomech Model Mechanobiol 2020; 19:1879-1896. [PMID: 32112154 DOI: 10.1007/s10237-020-01314-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/17/2020] [Indexed: 12/26/2022]
Abstract
Mechanical loading-induced fluid flow in lacunar-canalicular space (LCS) of bone excites osteocyte cells to release signalling molecules which initiate osteo-activities. Theoretical models considered canaliculi as a uniform and symmetrical space/channel in bone. However, experimental studies reported that canalicular walls are irregular and curvy resulting in inhomogeneous fluid motion which may influence the molecular transport. Therefore, a new mathematical model of LCS with curvy canalicular walls is developed to characterize cantilever bending-induced canalicular flow behaviour in terms of pore-pressure, fluid velocity, and streamlines. The model also analyses the mobility of signalling molecules involved in bone mechanotransduction as a function of loading frequency and permeability of LCS. Inhomogeneous flow is observed at higher loading frequency which amplifies mechanotransduction; nevertheless, it also promotes trapping of signalling molecules. The effects of shape and size of signalling molecules on transport behaviour are also studied. Trivially, signalling molecules larger in size and weight move slower as compared to molecules small in size and weight which validates the findings of the present study. The outcomes will ultimately be useful in designing better biomechanical exercise in combination with pharmaceutical agents to improve the bone health.
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