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Gatti V, Gelbs MJ, Guerra RB, Gerber MB, Fritton SP. Interstitial fluid velocity is decreased around cortical bone vascular pores and depends on osteocyte position in a rat model of disuse osteoporosis. Biomech Model Mechanobiol 2021; 20:1135-1146. [PMID: 33666792 DOI: 10.1007/s10237-021-01438-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 02/15/2021] [Indexed: 10/22/2022]
Abstract
Muscle paralysis induced with botulinum toxin (Botox) injection increases vascular porosity and reduces osteocyte lacunar density in the tibial cortical bone of skeletally mature rats. These morphological changes potentially affect interstitial fluid flow in the lacunar-canalicular porosity, which is thought to play a role in osteocyte mechanotransduction. The aim of this study was to investigate the effects of disuse-induced morphological changes on interstitial fluid velocity around osteocytes in the bone cortex. Micro-CT images from a previous study that quantified the effects of Botox-induced muscle paralysis on bone microarchitecture in skeletally mature rats were used to create high-resolution, animal-specific finite element models that included the vascular pores and osteocyte lacunae within the tibial metaphysis of Botox-injected (BTX, n = 8) and saline-injected control (CTRL, n = 8) groups. To quantify fluid flow, lacunar and canalicular porosities were modeled as fluid-saturated poroelastic materials, and boundary conditions were applied to simulate physiological loading. This modeling approach allowed a detailed quantification of the fluid flow velocities around osteocytes in a relatively large volume of bone tissue. The analysis demonstrated that interstitial fluid velocity at the vascular pore surfaces was significantly lower in BTX compared to CTRL because of the decreased vascular canal separation. No significant differences in average fluid velocity were observed at the osteocyte lacunae and no correlation was found between the fluid velocity and the lacunar density, which was significantly lower in BTX. Instead, the lacunar fluid velocity was dependent on the osteocyte's specific position in the bone cortex and its proximity to a vascular pore.
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Affiliation(s)
- Vittorio Gatti
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Michelle J Gelbs
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Rodrigo B Guerra
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Michael B Gerber
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Susannah P Fritton
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA.
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2
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Zheng T, Huang Y, Zhang X, Cai Q, Deng X, Yang X. Mimicking the electrophysiological microenvironment of bone tissue using electroactive materials to promote its regeneration. J Mater Chem B 2020; 8:10221-10256. [PMID: 33084727 DOI: 10.1039/d0tb01601b] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The process of bone tissue repair and regeneration is complex and requires a variety of physiological signals, including biochemical, electrical and mechanical signals, which collaborate to ensure functional recovery. The inherent piezoelectric properties of bone tissues can convert mechanical stimulation into electrical effects, which play significant roles in bone maturation, remodeling and reconstruction. Electroactive materials, including conductive materials, piezoelectric materials and electret materials, can simulate the physiological and electrical microenvironment of bone tissue, thereby promoting bone regeneration and reconstruction. In this paper, the structures and performances of different types of electroactive materials and their applications in the field of bone repair and regeneration are reviewed, particularly by providing the results from in vivo evaluations using various animal models. Their advantages and disadvantages as bone repair materials are discussed, and the methods for tuning their performances are also described, with the aim of providing an up-to-date account of the proposed topics.
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Affiliation(s)
- Tianyi Zheng
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
| | - Yiqian Huang
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
| | - Xuehui Zhang
- Department of Dental Materials & Dental Medical Devices Testing Center, Peking University School and Hospital of Stomatology, Beijing 100081, P. R. China
| | - Qing Cai
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
| | - Xuliang Deng
- Department of Geriatric Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081, P. R. China
| | - Xiaoping Yang
- State Key Laboratory of Organic-Inorganic Composites, Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
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3
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Zhao S, Liu H, Li Y, Song Y, Wang W, Zhang C. Numerical analysis of the flow field in the lacunar-canalicular system under different magnitudes of gravity. Med Biol Eng Comput 2020; 58:509-518. [DOI: 10.1007/s11517-019-02108-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 06/10/2019] [Indexed: 11/28/2022]
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4
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Behringer M, Skutschik C, Franz A. [Training methods and trainability]. DER ORTHOPADE 2019; 48:992-997. [PMID: 31659422 DOI: 10.1007/s00132-019-03827-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The need for effective training methods for positive adaptations in muscle strength and bone mineralization, suitable for all groups of patients, arises in both rehabilitation and pre-habilitation. In addition to mechanical stress, an increased metabolic stress, by means of reduced blood supply of the muscle, seems to induce positive adaptations as well. OBJECTIVES Description of the effects of resistance training and opportunities of blood-flow restriction training in a clinical setting. METHODS Key and specialized literature RESULTS: Regularly applied high mechanical loads are suitable to induce increases in muscle strength and mass as well as bone mineralization. In principle, the trainability of these tissues is given over the entire life span, although the adaptation of the muscle mass is reduced in the prepubertal and later stages of life. Classic strength training is particularly suitable as a training method to apply this stimulus quality (mechanical stress). For some years now, however, there has been increasing evidence that even low-intensity resistance training associated with metabolic stress is capable of producing hypertrophic effects and increasing muscle strength. This observation is particularly interesting for target groups whose mechanical capacity of the musculoskeletal system is reduced. Blood-flow-restriction training is particularly suitable as a training method for the application of this stimulus quality (metabolic stress). The data available on the effectiveness of low-intensity stress protocols on bone structure is still insufficient. Further research is needed to make evidence-based recommendations.
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Affiliation(s)
- M Behringer
- Sportmedizin und Leistungsphysiologie, Institut für Sportwissenschaften, Goethe Universität Frankfurt, Ginnheimer Landstraße 39, 60487, Frankfurt, Deutschland.
| | - C Skutschik
- Sportmedizin und Leistungsphysiologie, Institut für Sportwissenschaften, Goethe Universität Frankfurt, Ginnheimer Landstraße 39, 60487, Frankfurt, Deutschland
| | - A Franz
- Abteilung Prähabilitation und Muskelforschung, ATOS Orthoparc Klinik Köln, Köln, Deutschland
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5
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Mohammadkhah M, Marinkovic D, Zehn M, Checa S. A review on computer modeling of bone piezoelectricity and its application to bone adaptation and regeneration. Bone 2019; 127:544-555. [PMID: 31356890 DOI: 10.1016/j.bone.2019.07.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/17/2019] [Accepted: 07/20/2019] [Indexed: 02/07/2023]
Abstract
Bone is a hierarchical, multiphasic and anisotropic structure which in addition possess piezoelectric properties. The generation of piezoelectricity in bone is a complex process which has been shown to play a key role both in bone adaptation and regeneration. In order to understand the complex biological, mechanical and electrical interactions that take place during these processes, several computer models have been developed and used to test hypothesis on potential mechanisms behind experimental observations. This paper aims to review the available literature on computer modeling of bone piezoelectricity and its application to bone adaptation and healing. We first provide a brief overview of the fundamentals of piezoelectricity and bone piezoelectric effects. We then review how these properties have been used in computational models of bone adaptation and electromechanical behaviour of bone. In addition, in the last section, we summarize current limitations and potential directions for future work.
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Affiliation(s)
- Melika Mohammadkhah
- Department of Structural Mechanics, Berlin Institute of Technology, Fakultät V - Institut für Mechanik, FG Strukturmechanik und Strukturberechnung, Sekr. C 8-3, Geb. M Str. des 17, Juni 135, D-10623 Berlin, Germany.
| | - Dragan Marinkovic
- Department of Structural Mechanics, Berlin Institute of Technology, Fakultät V - Institut für Mechanik, FG Strukturmechanik und Strukturberechnung, Sekr. C 8-3, Geb. M Str. des 17, Juni 135, D-10623 Berlin, Germany; Faculty of Mechanical Engineering, University of Nis, Aleksandra Medvedeva 14, 18000 Nis, Serbia.
| | - Manfred Zehn
- Department of Structural Mechanics, Berlin Institute of Technology, Fakultät V - Institut für Mechanik, FG Strukturmechanik und Strukturberechnung, Sekr. C 8-3, Geb. M Str. des 17, Juni 135, D-10623 Berlin, Germany.
| | - Sara Checa
- Department of Structural Mechanics, Berlin Institute of Technology, Fakultät V - Institut für Mechanik, FG Strukturmechanik und Strukturberechnung, Sekr. C 8-3, Geb. M Str. des 17, Juni 135, D-10623 Berlin, Germany; Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Föhrer Str. 15, 13353 Berlin, Germany.
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6
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Behringer M, Willberg C. Application of Blood Flow Restriction to Optimize Exercise Countermeasures for Human Space Flight. Front Physiol 2019; 10:33. [PMID: 30740059 PMCID: PMC6355682 DOI: 10.3389/fphys.2019.00033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/11/2019] [Indexed: 11/13/2022] Open
Abstract
In recent years there has been a strong increase in publications on blood flow restriction (BFR) training. In particular, the fact that this type of training requires only low resistance to induce muscle strength and mass gains, makes BFR training interesting for athletes and scientists alike. For the same reason this type of training is particularly interesting for astronauts working out in space. Lower resistance during training would have the advantage of reducing the risk of strain-induced injuries. Furthermore, strength training with lower resistances would have implications for the equipment required for training under microgravity conditions, as significantly lower resistances have to be provided by the training machines. Even though we are only about to understand the effects of blood flow restriction on exercise types other than low-intensity strength training, the available data indicate that BFR of leg muscles is also able to improve the training effects of walking or running at slow speeds. The underlying mechanisms of BFR-induced functional and structural adaptations are still unclear. An essential aspect seems to be the premature fatigue of Type-I muscle fibers, which requires premature recruitment of Type-II muscle fibers to maintain a given force output. Other theories assume that cell swelling, anabolic hormones, myokines and reactive oxygen species are involved in the mediation of BFR training-related effects. This review article is intended to summarize the main advantages and disadvantages, but also the potential risks of such training for astronauts.
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Affiliation(s)
- Michael Behringer
- Institute of Sports Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Christina Willberg
- Institute of Sports Sciences, Goethe University Frankfurt, Frankfurt, Germany
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7
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Dissaux C, Wagner D, George D, Spingarn C, Rémond Y. Mechanical impairment on alveolar bone graft: A literature review. J Craniomaxillofac Surg 2019; 47:149-157. [DOI: 10.1016/j.jcms.2018.10.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/08/2018] [Accepted: 10/30/2018] [Indexed: 10/27/2022] Open
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8
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Kao FC, Chiu PY, Tsai TT, Lin ZH. The application of nanogenerators and piezoelectricity in osteogenesis. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2019; 20:1103-1117. [PMID: 32002085 PMCID: PMC6968561 DOI: 10.1080/14686996.2019.1693880] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/29/2019] [Accepted: 11/13/2019] [Indexed: 05/13/2023]
Abstract
Bone is a complex organ possessing both physicomechanical and bioelectrochemical properties. In the view of Wolff's Law, bone can respond to mechanical loading and is subsequently reinforced in the areas of stress. Piezoelectricity is one of several mechanical responses of the bone matrix that allows osteocytes, osteoblasts, osteoclasts, and osteoprogenitors to react to changes in their environment. The present review details how osteocytes convert external mechanical stimuli into internal bioelectrical signals and the induction of intercellular cytokines from the standpoint of piezoelectricity. In addition, this review introduces piezoelectric and triboelectric materials used as self-powered electrical generators to promote osteogenic proliferation and differentiation due to their electromechanical properties, which could promote the development of promising applications in tissue engineering and bone regeneration.
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Affiliation(s)
- Fu-Cheng Kao
- Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu, Taiwan
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu, Taiwan
- Department of Orthopaedic Surgery, Spine Section, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Ping-Yeh Chiu
- Department of Orthopaedic Surgery, Spine Section, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Tsung-Ting Tsai
- Department of Orthopaedic Surgery, Spine Section, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Zong-Hong Lin
- Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu, Taiwan
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan
- Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu, Taiwan
- CONTACT Zong-Hong Lin Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
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9
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Moser C, Bardsley K, El Haj AJ, Alini M, Stoddart MJ, Bara JJ. A Perfusion Culture System for Assessing Bone Marrow Stromal Cell Differentiation on PLGA Scaffolds for Bone Repair. Front Bioeng Biotechnol 2018; 6:161. [PMID: 30525030 PMCID: PMC6262350 DOI: 10.3389/fbioe.2018.00161] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 10/16/2018] [Indexed: 12/31/2022] Open
Abstract
Biomaterials development for bone repair is currently hindered by the lack of physiologically relevant in vitro testing systems. Here we describe the novel use of a bi-directional perfusion bioreactor to support the long term culture of human bone marrow stromal cells (BMSCs) differentiated on polylactic co-glycolic acid (PLGA). Primary human BMSCs were seeded onto porous PLGA scaffolds and cultured in static vs. perfusion culture conditions for 21 days in osteogenic vs. control media. PLGA scaffolds were osteoconductive, supporting a mature osteogenic phenotype as shown by the upregulation of Runx2 and the early osteocyte marker E11. Perfusion culture enhanced the expression of osteogenic genes Osteocalcin and Osteopontin. Extracellular matrix deposition and mineralisation were spatially regulated within PLGA scaffolds in a donor dependant manner. This, together with the observed upregulation of Collagen type X suggested an environment permissive for the study of differentiation pathways associated with both intramembranous and endochondral ossification routes of bone healing. This culture system offers a platform to assess BMSC behavior on candidate biomaterials under physiologically relevant conditions. Use of this system may improve our understanding of the environmental cues orchestrating BMSC differentiation and enable fine tuning of biomaterial design as we develop tissue-engineered strategies for bone regeneration.
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Affiliation(s)
- Caroline Moser
- AO Research Institute Davos, Davos, Switzerland.,Laboratory for Translational Nutritional Biology, Department of Health Sciences and Technologies, Institute of Food Nutrition and Health, ETH Zürich, Zürich, Switzerland
| | - Katie Bardsley
- Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom
| | - Alicia J El Haj
- Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom.,Healthcare Technology Institute, Institute of Translational Medicine, University of Birmingham, Birmingham, United Kingdom
| | - Mauro Alini
- AO Research Institute Davos, Davos, Switzerland
| | - Martin J Stoddart
- AO Research Institute Davos, Davos, Switzerland.,Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom
| | - Jennifer J Bara
- AO Research Institute Davos, Davos, Switzerland.,Department of Orthopaedic Surgery, Washington University, St Louis, MO, United States
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10
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A theory for bone resorption based on the local rupture of osteocytes cells connections: A finite element study. Math Biosci 2015; 262:46-55. [DOI: 10.1016/j.mbs.2015.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 01/18/2015] [Accepted: 01/20/2015] [Indexed: 11/23/2022]
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11
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Knapik DM, Perera P, Nam J, Blazek AD, Rath B, Leblebicioglu B, Das H, Wu LC, Hewett TE, Agarwal SK, Robling AG, Flanigan DC, Lee BS, Agarwal S. Mechanosignaling in bone health, trauma and inflammation. Antioxid Redox Signal 2014; 20:970-85. [PMID: 23815527 PMCID: PMC3924811 DOI: 10.1089/ars.2013.5467] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
SIGNIFICANCE Mechanosignaling is vital for maintaining the structural integrity of bone under physiologic conditions. These signals activate and suppress multiple signaling cascades regulating bone formation and resorption. Understanding these pathways is of prime importance to exploit their therapeutic potential in disorders associated with bone loss due to disuse, trauma, or disruption of homeostatic mechanisms. RECENT ADVANCES In the case of cells of the bone, an impressive amount of data has been generated that provides evidence of a complex mechanism by which mechanical signals can maintain or disrupt cellular homeostasis by driving transcriptional regulation of growth factors, matrix proteins and inflammatory mediators in health and inflammation. Mechanical signals act on cells in a magnitude dependent manner to induce bone deposition or resorption. During health, physiological levels of these signals are essential for maintaining bone strength and architecture, whereas during inflammation, similar signals can curb inflammation by suppressing the nuclear factor kappa B (NF-κB) signaling cascade, while upregulating matrix synthesis via mothers against decapentaplegic homolog and/or Wnt signaling cascades. Contrarily, excessive mechanical forces can induce inflammation via activation of the NF-κB signaling cascade. CRITICAL ISSUES Given the osteogenic potential of mechanical signals, it is imperative to exploit their therapeutic efficacy for the treatment of bone disorders. Here we review select signaling pathways and mediators stimulated by mechanical signals to modulate the strength and integrity of the bone. FUTURE DIRECTIONS Understanding the mechanisms of mechanotransduction and its effects on bone lay the groundwork for development of nonpharmacologic mechanostimulatory approaches for osteodegenerative diseases and optimal bone health.
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Affiliation(s)
- Derrick M Knapik
- 1 Department of Orthopaedic Surgery, The Ohio State University College of Medicine , Columbus, Ohio
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12
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Vacek TP, Kalani A, Voor MJ, Tyagi SC, Tyagi N. The role of homocysteine in bone remodeling. Clin Chem Lab Med 2013; 51:579-90. [PMID: 23449525 DOI: 10.1515/cclm-2012-0605] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 01/31/2013] [Indexed: 01/08/2023]
Abstract
Bone remodeling is a very complex process. Homocysteine (Hcy) is known to modulate this process via several known mechanisms such as increase in osteoclast activity, decrease in osteoblast activity and direct action of Hcy on bone matrix. Evidence from previous studies further support a detrimental effect on bone via decrease in bone blood flow and an increase in matrix metalloproteinases (MMPs) that degrade extracellular bone matrix. Hcy binds directly to extracellular matrix and reduces bone strength. There are several bone markers that can be used as parameters to determine how high levels of plasma Hcy (hyperhomocysteinemia, HHcy) affect bone such as: hydroxyproline, N-terminal collagen 1 telopeptides. Mitochondrion serves an important role in generating reactive oxygen species (ROS). Mitochondrial abnormalities have been identified during HHcy. The mechanism of Hcy-induced bone remodeling via the mitochondrial pathway is largely unknown. Therefore, we propose a mitochondrial mechanism by which Hcy can contribute to alter bone properties. This may occur both through generations of ROS that activate MMPs and could be extruded into matrix to degrade bone matrix. However, there are contrasting reports on whether Hcy affects bone density, with some reports in favour and others not. Earlier studies also found an alteration in bone biomechanical properties with deficiencies of vitamin B12, folate and HHcy conditions. Moreover, existing data opens speculation that folate and vitamin therapy act not only via Hcy-dependent pathways but also via Hcy-independent pathways. However, more studies are needed to clarify the mechanistic role of Hcy during bone diseases.
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Affiliation(s)
- Thomas P Vacek
- Department of Physiology and Biophysics, University of Louisville School of Medicine Louisville, Louisville, KY 40202, USA
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13
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Fazzalari NL, Martin BL, Reynolds KJ, Cleek TM, Badiei A, Bottema MJ. A model for the change of cancellous bone volume and structure over time. Math Biosci 2012; 240:132-40. [PMID: 22796394 DOI: 10.1016/j.mbs.2012.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 05/15/2012] [Accepted: 06/20/2012] [Indexed: 10/28/2022]
Abstract
A model is presented for characterizing the process by which cancellous bone changes in volume and structure over time. The model comprises simulations of local changes resulting from individual remodelling events, known as bone multicellular units (BMU), and an ordinary differential equation for connecting the number of remodelling events to real time. The model is validated on micro-CT scans of tibiae of normal rats, estrogen deprived rats and estrogen deprived rats treated with bisphosphonates. The model explains the asymptotic trends seen in changes of bone volume over time resulting from estrogen deprivation as well as trends seen subsequent to treatment. The model demonstrates that both bone volume and structure changes can be explained in terms of resetting remodelling parameters. The model also shows that either current understanding of the effects of bisphosphonates is not correct or that the simplest description of remodelling does not suffice to explain both the change in bone volume and structure of rats treated with bisphosphonates.
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Affiliation(s)
- Nicola L Fazzalari
- Bone and Joint Research Laboratory, Institute of Medical and Veterinary Science, Adelaide, SA, Australia
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14
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Fernández JR, García-Aznar JM, Martínez R. Piezoelectricity could predict sites of formation/resorption in bone remodelling and modelling. J Theor Biol 2011; 292:86-92. [PMID: 22001080 DOI: 10.1016/j.jtbi.2011.09.032] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 09/27/2011] [Accepted: 09/30/2011] [Indexed: 11/25/2022]
Abstract
We have developed a mathematical approach for modelling the piezoelectric behaviour of bone tissue in order to evaluate the electrical surface charges in bone under different mechanical conditions. This model is able to explain how bones change their curvature, where osteoblasts or osteoclasts could detect in the periosteal/endosteal surfaces the different electrical charges promoting bone formation or resorption. This mechanism also allows to understand the BMU progression in function of the electro-mechanical bone behaviour.
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Affiliation(s)
- J R Fernández
- Departamento de Matemática Aplicada I, Universidade de Vigo ETSI Telecomunicación, Vigo, Spain
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15
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Apolinário JDC, Coelho WMD, Louzada MJQ. Análise da influência do ultrassom de baixa intensidade na região de reparo ósseo em ratos sob ausência de carga. FISIOTERAPIA E PESQUISA 2011. [DOI: 10.1590/s1809-29502011000300013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Há evidências de que o ultrassom (US) de baixa intensidade pode acelerar a regeneração óssea. Este trabalho objetivou verificar a ação do US no defeito ósseo, criado experimentalmente em tíbias de ratos sob ausência de carga. Vinte Rattus novergicus albinus, Wistar adultos, divididos em: G1 (n=10), grupo experimental de 15 dias sem suspensão, e G2 (n=10), grupo experimental de 15 dias suspenso pela cauda, foram submetidos à osteotomia em ambas as tíbias e à aplicação do US, frequência de 1,5 MHz, ciclo de trabalho 1:4, 30 mW/cm², nas tíbias direitas por 12 sessões de 20 minutos. Após o sacrifício, as tíbias foram submetidas à análise da Densidade Mineral Óssea (DMO). Os resultados demonstraram DMO de 0,139±0,018 g/cm² para tíbia tratada; 0,131±0,009 g/cm² para tíbia controle no G1; e no G2 registrou-se 0,120±0,009 g/cm² para tíbia tratada e 0,106±0,017 g/cm² para tíbia controle. Houve diferença significante entre os grupos nos quais o G2 apresentou menor DMO, o que demonstra que a suspensão prejudica a manutenção das propriedades ósseas, e entre as tíbias tratadas e controles do G2, demonstrando que o US acelerou o processo de reparo, concluindo que a impossibilidade do estímulo mecânico causada pela não deambulação em um processo de reparo ósseo pode ser minimizada pela ação do US. No G1, a aplicação do US não teve influência significante no aumento da DMO, talvez pelo fato dos animais já terem estímulo mecânico suficiente à formação óssea.
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16
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Affiliation(s)
- Chenyu Huang
- Department of Plastic, Reconstructive and Aesthetic SurgeryNippon Medical School Tokyo Japan
- Department of Plastic SurgeryMeitan General Hospital Beijing China
| | - Rei Ogawa
- Department of Plastic, Reconstructive and Aesthetic SurgeryNippon Medical School Tokyo Japan
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17
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Chen JH, Liu C, You L, Simmons CA. Boning up on Wolff's Law: mechanical regulation of the cells that make and maintain bone. J Biomech 2009; 43:108-18. [PMID: 19818443 DOI: 10.1016/j.jbiomech.2009.09.016] [Citation(s) in RCA: 204] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2009] [Indexed: 12/31/2022]
Abstract
Bone tissue forms and is remodeled in response to the mechanical forces that it experiences, a phenomenon described by Wolff's Law. Mechanically induced formation and adaptation of bone tissue is mediated by bone cells that sense and respond to local mechanical cues. In this review, the forces experienced by bone cells, the mechanotransduction pathways involved, and the responses elicited are considered. Particular attention is given to two cell types that have emerged as key players in bone mechanobiology: osteocytes, the putative primary mechanosensors in intact bone; and osteoprogenitors, the cells responsible for bone formation and recently implicated in ectopic calcification of cardiovascular tissues. Mechanoregulation of bone involves a complex interplay between these cells, their microenvironments, and other cell types. Thus, dissection of the role of mechanics in regulating bone cell fate and function, and translation of that knowledge to improved therapies, requires identification of relevant cues, multifactorial experimental approaches, and advanced model systems that mimic the mechanobiological environment.
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Affiliation(s)
- Jan-Hung Chen
- Department of Mechanical & Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, ON, Canada M5S 3G8
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Riddle RC, Donahue HJ. From streaming-potentials to shear stress: 25 years of bone cell mechanotransduction. J Orthop Res 2009; 27:143-9. [PMID: 18683882 DOI: 10.1002/jor.20723] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Mechanical loads are vital regulators of skeletal mass and architecture as evidenced by the increase in bone formation following the addition of exogenous loads and loss of bone mass following their removal. While our understanding of the molecular mechanisms by which bone cells perceive changes in their mechanical environment has increased rapidly in recent years, much remains to be learned. Here, we outline the effects of interstitial fluid flow, a potent biophysical signal induced by the deformation of skeletal tissue in response to applied loads, on bone cell behavior. We focus on the molecular mechanisms by which bone cells are hypothesized to perceive interstitial fluid flow, the cell signaling cascades activated by fluid flow, and the use of this signal in tissue engineering protocols.
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Affiliation(s)
- Ryan C Riddle
- Division of Cellular and Molecular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Fritton SP, Weinbaum S. Fluid and Solute Transport in Bone: Flow-Induced Mechanotransduction. ANNUAL REVIEW OF FLUID MECHANICS 2009; 41:347-374. [PMID: 20072666 PMCID: PMC2805256 DOI: 10.1146/annurev.fluid.010908.165136] [Citation(s) in RCA: 232] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Much recent evidence suggests that bone cells sense their mechanical environment via interstitial fluid flow. In this review, we summarize theoretical and experimental approaches to quantify fluid and solute transport in bone, starting with the early investigations of fluid shear stress applied to bone cells. The pathways of bone interstitial fluid and solute movement are high-lighted based on recent theoretical models, as well as a new generation of tracer experiments that have clarified and refined the structure and function of the osteocyte pericellular matrix. Then we trace how the fluid-flow models for mechanotransduction have evolved as new ultrastructural features of the osteocyte lacunar-canalicular porosity have been identified and how more recent in vitro fluid-flow and cell-stretch experiments have helped elucidate at the molecular level the possible pathways for cellular excitation in bone.
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Affiliation(s)
- Susannah P. Fritton
- Department of Biomedical Engineering, City College of New York, New York, New York 10031
| | - Sheldon Weinbaum
- Department of Biomedical Engineering, City College of New York, New York, New York 10031
- Department of Mechanical Engineering, City College of New York, New York, New York 10031
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Abstract
Mechanical signals are major regulators of skeletal homeostasis as the addition of exogenous load is followed by enhanced bone formation and the removal of normal loads is followed by net bone loss. The mechanism by which bone cells perceive and respond to changes in their biophysical environment are still poorly understood, but it is widely accepted that the detection of interstitial fluid flow is an initiating cue. In this chapter, we describe two in vitro systems designed to examine the effects of fluid flow on bone cell behavior and to elucidate the signaling cascades activated by this stimulus. The first utilizes a parallel plate flow chamber designed to stimulate a single bone cell type grown on glass slides. The second employs a rotating disk fluid flow apparatus. Commercially-available cell culture inserts allow one type of bone cell to be exposed to fluid flow and signals to be communicated to a second bone cell model not exposed to fluid flow.
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