scholarly journals The mechanoresponse of bone is closely related to the osteocyte lacunocanalicular network architecture

2020 ◽  
Vol 117 (51) ◽  
pp. 32251-32259
Author(s):  
Alexander Franciscus van Tol ◽  
Victoria Schemenz ◽  
Wolfgang Wagermaier ◽  
Andreas Roschger ◽  
Hajar Razi ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Network Structure ◽  
Network Architecture ◽  
Local Strain ◽  
Bone Adaptation ◽  
Micro Computed Tomography ◽  
Entire Cross Section ◽  
Element Analysis ◽  
3D Network

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.

scholarly journals Cancellous bone adaptation to tibial compression is not sex dependent in growing mice

2010 ◽  
Vol 109 (3) ◽  
pp. 685-691 ◽  
Author(s):  
Maureen E. Lynch ◽  
Russell P. Main ◽  
Qian Xu ◽  
Daniel J. Walsh ◽  
Mitchell B. Schaffler ◽  
...  
Keyword(s):  
Bone Mass ◽  
Mechanical Loading ◽  
Cancellous Bone ◽  
Adaptive Response ◽  
Bone Adaptation ◽  
Micro Computed Tomography ◽  
Element Analysis ◽  
Male And Female ◽  
And Control

Mechanical loading can be used to increase bone mass and thus attenuate pathological bone loss. Because the skeleton's adaptive response to loading is most robust before adulthood, elucidating sex-specific responses during growth may help maximize peak bone mass. This study investigated the effect of sex on the response to controlled, in vivo mechanical loading in growing mice. Ten-week-old male and female C57Bl/6 mice underwent noninvasive compression of the left tibia. Peak loads of −11.5 N were applied, corresponding to +1,200 με at the tibial midshaft in both sexes. Cancellous bone mass, architecture, and dynamic formation in the proximal metaphysis were compared between loaded and control limbs via micro-computed tomography and histomorphometry. The strain environment of the proximal metaphysis during loading was characterized using finite element analysis. Both sexes responded to tibial compression through increased bone mass and altered architecture. Cancellous bone mass and tissue density were enhanced in loaded limbs relative to control limbs in both sexes through trabecular thickening and reduced separation. Changes in mass were due to increased cellular activity in loaded limbs compared with control limbs. Adaptation to loading increased the proportion of load transferred by the cancellous bone in the proximal metaphysis. For all cancellous measures, the response to tibial compression did not differ between male and female mice. When similar strains are engendered in males and females, the adaptive response in cancellous bone to mechanical loading does not depend on sex.

An Improved In Vivo Rat Tail Vertebra Model for the Study of Trabecular Bone Adaptation

1999 ◽  
Author(s):  
Mark J. Eichler ◽  
Chi Hyun Kim ◽  
X. Edward Guo
Keyword(s):  
Trabecular Bone ◽  
Large Scale ◽  
Bone Fractures ◽  
Mechanical Load ◽  
Bone Adaptation ◽  
Surgical Trauma ◽  
Micro Computed Tomography ◽  
Age Related ◽  
Rat Tail

Abstract The role of mechanical loading in trabecular bone adaptation is important for the understanding of bone integrity in different loading scenarios such as microgravity and for the etiology of age-related bone fractures. There have been numerous in vivo animal studies of bone adaptation, most of which are related to cortical bone remodeling, aimed at the investigation of Wolff’s Law [4], An interesting experimental model for trabecular bone adaptation has been developed in the rat tail vertebrae [2,3]. This model is attractive for trabecular bone adaptation studies because a controlled mechanical load can be applied to a whole vertebra with minimal surgical trauma, using a relatively inexpensive animal model. In addition, with advanced micro computed tomography (micro-CT) or micro magnetic resonance imaging (micro-MRI) coupled with large scale finite element modeling techniques, it is possible to characterize the three-dimensional (3D) stress/strain environment in the bone tissue close to a cellular level (∼25μm) [1]. Therefore, this in vivo rat tail model has a tremendous potential for quantification of the relationship between mechanical stimulation and biological response in trabecular bone adaptation.

Tissue Engineered Bone Using Polycaprolactone Scaffolds Made by Selective Laser Sintering

2004 ◽  
Vol 845 ◽  
Author(s):  
J. M. Williams ◽  
A. Adewunmi ◽  
R. M. Schek ◽  
C. L. Flanagan ◽  
P. H. Krebsbach ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Selective Laser Sintering ◽  
Mandibular Condyle ◽  
Computational Design ◽  
Laser Sintering ◽  
Histological Evaluation ◽  
Micro Computed Tomography ◽  
Element Analysis ◽  
Immunocompromised Mice

ABSTRACTPolycaprolactone is a bioresorbable polymer that has potential for tissue engineering of bone and cartilage. In this work, we report on the computational design and freeform fabrication of porous polycaprolactone scaffolds using selective laser sintering, a rapid prototyping technique. The microstructure and mechanical properties of the fabricated scaffolds were assessed and compared to designed porous architectures and computationally predicted properties. Compressive modulus and yield strength were within the lower range of reported properties for human trabecular bone. Finite element analysis showed that mechanical properties of scaffold designs and of fabricated scaffolds can be computationally predicted. Scaffolds were seeded with BMP-7 transduced fibroblasts and implanted subcutaneously in immunocompromised mice. Histological evaluation and micro-computed tomography (μCT) analysis confirmed that bone was generated in vivo. Finally, we have demonstrated the clinical application of this technology by producing a prototype mandibular condyle scaffold based on an actual pig condyle.

In Vivo Mesenchymal Stem Cell Proliferation in Response to Dynamic Fluid Flow Stimulation

2012 ◽  
Author(s):  
M. Hu ◽  
R. Yeh ◽  
M. Lien ◽  
Y. X. Qin
Keyword(s):  
Fluid Flow ◽  
Bone Tissue ◽  
Bone Adaptation ◽  
Hindlimb Suspension ◽  
Osteoporotic Bone ◽  
Hydraulic Stimulation ◽  
Structural Deterioration ◽  
Bone Fluid Flow ◽  
Cord Injury

Osteoporosis is a debilitating disease characterized as decreased bone mass and structural deterioration of bone tissue. Osteoporotic bone tissue turns itself into altered structure, which leads to weaker bones that are more susceptible for fractures. While often happening in elderly, long-term bed-rest patients, e.g. spinal cord injury, and astronauts who participate in long-duration spaceflights, osteoporosis has been considered as a major public health thread and causes great medical cost impacts to the society. Mechanobiology and novel stimulation on regulating bone health have long been recognized. Loading induced bone fluid flow, as a critical mechanotransductive promoter, has been demonstrated to regulate cellular signaling, osteogenesis, and bone adaptation [4]. As one of the factors that mediate bone fluid flow, intromedullary pressure (ImP) creates a pressure gradient that further influence the magnitude of mechanotransductory signals [5]. As for a potential translational development of ImP, our group has recently introduced a novel, non-invasive dynamic hydraulic stimulation (DHS) on bone structural enhancement. Its promising effects on inhibition of disuse bone loss has been shown with 2 Hz loading through a 4-week hindlimb suspension rat study followed by microCT analysis. At the cellular level, mesenchymal stem cells (MSCs) are defined by their self-renewal ability and that to potentially differentiate into the cells that form tissues such as bone [1]. To further elucidate the cellular effects of DHS and its potential mechanism on bone quality enhancement, the objective of this study was to measure MSC quantification in response to the in vivo mechanical signals driven by DHS.

Induced Intramedullary Pressure by Dynamic Hydraulic Stimulation and Its Potential in Attenuation of Bone Loss

2011 ◽  
Author(s):  
M. Hu ◽  
J. Cheng ◽  
S. Ferreri ◽  
F. Serra-Hsu ◽  
W. Lin ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Bone Loss ◽  
Bone Adaptation ◽  
Dependent Manner ◽  
Hydraulic Stimulation ◽  
Flow Coupling ◽  
Bone Fluid Flow ◽  
Intramedullary Pressure ◽  
New Treatments

Bone loss is a critical health problem of astronauts in long-term space missions. A growing number of evidence has pointed out bone fluid flow as a critical regulator in mechanotransductive signaling and bone adaptation. Intramedullary pressure (ImP) is a key mediator for bone fluid flow initiation and it influences the osteogenic signals within the skeleton. The potential ImP-induced bone fluid flow then triggers bone adaptation [1]. Previous in vivo study has demonstrated that ImP induced by oscillatory electrical stimulations can effectively mitigate disuse osteopenia in a frequency-dependent manner in a disuse rat model [2, 3]. In order to develop the translational potentials of ImP, a non-invasive intervention with direct fluid flow coupling is necessary to develop new treatments for microgravity-induced osteopenia/osteoporosis.

scholarly journals Exploratory Full-Field Strain Analysis of Regenerated Bone Tissue from Osteoinductive Biomaterials

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 168 ◽  
Author(s):  
Marta Peña Fernández ◽  
Cameron Black ◽  
Jon Dawson ◽  
David Gibbs ◽  
Janos Kanczler ◽  
...  
Keyword(s):  
Bone Regeneration ◽  
Bone Tissue ◽  
Bone Structure ◽  
Strain Analysis ◽  
Local Strain ◽  
Field Strain ◽  
Micro Computed Tomography ◽  
Promising Alternative ◽  
Full Field

Biomaterials for bone regeneration are constantly under development, and their application in critical-sized defects represents a promising alternative to bone grafting techniques. However, the ability of all these materials to produce bone mechanically comparable with the native tissue remains unclear. This study aims to explore the full-field strain evolution in newly formed bone tissue produced in vivo by different osteoinductive strategies, including delivery systems for BMP-2 release. In situ high-resolution X-ray micro-computed tomography (microCT) and digital volume correlation (DVC) were used to qualitatively assess the micromechanics of regenerated bone tissue. Local strain in the tissue was evaluated in relation to the different bone morphometry and mineralization for specimens (n = 2 p/treatment) retrieved at a single time point (10 weeks in vivo). Results indicated a variety of load-transfer ability for the different treatments, highlighting the mechanical adaptation of bone structure in the early stages of bone healing. Although exploratory due to the limited sample size, the findings and analysis reported herein suggest how the combination of microCT and DVC can provide enhanced understanding of the micromechanics of newly formed bone produced in vivo, with the potential to inform further development of novel bone regeneration approaches.

In vivo micro computed tomography allows monitoring of load induced microstructural bone adaptation

Bone ◽  
2009 ◽  
Vol 44 ◽  
pp. S300 ◽  
Author(s):  
F.M. Lambers⁎ ◽  
G. Kuhn ◽  
F.A. Gerhard ◽  
R. Muller
Keyword(s):  
Computed Tomography ◽  
Bone Adaptation ◽  
Micro Computed Tomography

scholarly journals Comparative skull biomechanics in Varanus and Salvator ‘Tupinambis’

2017 ◽  
Author(s):  
Hugo Dutel ◽  
Alana C Sharp ◽  
Marc E H Jones ◽  
Susan E Evans ◽  
Micheal J Fagan ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Feeding Behaviour ◽  
Micro Computed Tomography ◽  
Lizard Species ◽  
Element Analysis ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Computer Based ◽  
Morphological Differences

The lizard species Salvator ‘Tupinambis’ merianae and Varanus ornatus evolved independently in South America and Africa but share similar ecology and feeding behaviour, despite having notable differences in their skull structure. Tupinambis has a compact, relatively short and wide snout, whereas that of Varanus is more slender and narrow. In addition, a postorbital bar (POB) is present in Tupinambis but absent in Varanus, and the former lacks the mid-frontal suture that is present in the latter. Here, we explore the biomechanical significance of these differences using 3D computer-based mechanical simulations based on micro-computed tomography, detailed muscle dissections, and in vivo data. First, we simulated muscle activity and joint-reaction forces during biting using Multibody Dynamics Analysis. Then, the forces calculated from these models were used as an input for Finite Element Analysis, to investigate and compare the strains of the skull in these two species. The effects of the presence/absence of structures, such as the POB, were investigated by constructing artificial models which geometry was altered. Our results indicate that strains in the skull bones are lower in Tupinambis than in Varanus, in particular at the back of the skull. The presence of a POB clearly reduces the strains in the bones during posterior biting in Tupinambis, but not in Varanus. Our results hence highlight how the morphological differences between these two taxa affect the mechanical behaviour of their respective skulls during feeding.

In vivo validation of a computational bone adaptation model using open-loop control and time-lapsed micro-computed tomography

Bone ◽  
2011 ◽  
Vol 49 (6) ◽  
pp. 1166-1172 ◽  
Author(s):  
Friederike A. Schulte ◽  
Floor M. Lambers ◽  
Duncan J. Webster ◽  
Gisela Kuhn ◽  
Ralph Müller
Keyword(s):  
Computed Tomography ◽  
Open Loop ◽  
Bone Adaptation ◽  
Open Loop Control ◽  
Micro Computed Tomography ◽  
Loop Control ◽  
Adaptation Model ◽  
In Vivo Validation

Micro-Computed Tomography to Finite Element Analysis of In Vivo Biodegradable Magnesium-Alloy Screw and Surrounding Bone in Rabbit Femurs

2015 ◽  
Author(s):  
Adrienne F. O. Williams ◽  
Matthew B. A. McCullough
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Mg Alloy ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Element Analysis ◽  
Animal Modeling ◽  
Finite Element Software ◽  
Over Time

Magnesium (Mg) and its alloys are attractive orthopedic biomaterials because of their degradability and mechanical properties, which are similar to bone’s. Characterizing the mechanical changes and interactions of these promising degradable biomaterials and the host environment (bone) is essential to their success in orthopedic devices. The objective of this study was to develop a protocol to evaluate in vivo biodegradable Mg-alloy screws and surrounding new and cancellous bone in rabbit femurs over time, using high resolution micro-computed tomography (micro-CT) images and the finite element method. Micro-CT was used to visually evaluate bone remodeling and degradation of Mg-alloy screws that were implanted in rabbit femoral condyles for 2, 4, 12, 24, 36 and 52 weeks. Over time, the degradation product around the device and the remainder of the intact core was observed. Scans were segmented into bone, degradation/corrosion products and non-degraded device, then reconstructed into 3D volumes. These volumes were meshed and assigned material properties based on CT data. The meshed volumes were exported to finite element software and analyzed in a virtual environment. Several foundational observations were made about animal modeling of in vivo degrading magnesium devices with a micro-CT to FEA protocol.

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