Bone Adaptation In Response To Mechanical Loading Is Greatest With A Large Initial Deviation In Loading Pattern
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Bone Adaptation In Response To Mechanical Loading Is Greatest With A Large Initial Deviation In Loading Pattern
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Author : Jennifer Lynn Schriefer
language : en
Publisher:
Release Date : 2004
Bone Adaptation In Response To Mechanical Loading Is Greatest With A Large Initial Deviation In Loading Pattern written by Jennifer Lynn Schriefer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with Bones categories.
Mechanical Factors In Initial Long Bone Ossification And Later Functional Adaptation
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Author : Julia Chinghua Chen
language : en
Publisher:
Release Date : 2010
Mechanical Factors In Initial Long Bone Ossification And Later Functional Adaptation written by Julia Chinghua Chen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
Our bones constantly adapt to their mechanical environment through a biological response from the womb to the tomb. Mechanobiology, the biological response to mechanical loading, is important for determining various properties of bone such as size and shape. During embryonic development, rapid growth generates significant tension in the periosteum, and tension has previously been shown to lead to bone apposition. In adults, intracortical stresses dominate and increased loading leads to elevated rates in bone apposition. Periosteal tension and intracortical stresses, then, are both experienced by bones, but their influences on bone apposition rates vary over time. This dissertation analyzes how embryonic bone growth rates and adult bone adaptation rates in long bones are related to their respective mechanical environments. The hypothesis that bones grow and adapt at rates corresponding to changes in the mechanical environment is investigated. In the first study, I investigated the mechanical environment of the periosteum during embryonic growth and its relationship to bone growth rates. The specific growth rate, or percent growth per day, was calculated using microCT images taken over embryonic days 11-20. Bones grew faster in length than in circumference during this time. Finite element techniques were then used to analyze the opening dimensions of incisions through the periosteum. Longitudinal and circumferential residual strains decreased from 46.2% to 29.3%, and 10.6% to 3.9%, respectively, during embryonic days 14-20. Residual strains were positively correlated to specific growth rates (p
Mechanical Loading And Bone
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Author : Jonathan H. Tobias
language : en
Publisher: Frontiers Media SA
Release Date : 2016-01-20
Mechanical Loading And Bone written by Jonathan H. Tobias and has been published by Frontiers Media SA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-01-20 with Diseases of the endocrine glands. Clinical endocrinology categories.
This research topic is focused on recent advances in our understanding of effects of mechanical loading on the skeleton, and research methods used in addressing these. Though it is well established that mechanical loading provides an essential stimulus for skeletal growth and maintenance, there have been major advances recently in terms of our understanding of the molecular pathways involved, which are thought to provide novel drug targets for treating osteoporosis. The articles included in this topic encompass the full spectrum of laboratory and clinical research, and range from review articles, editorials, hypothesis papers and original research articles. Together, they demonstrate how mechanical loading underpins many aspects of bone biology, including the pathogenesis and treatment of osteoporosis and other clinical disorders associated with skeletal fragility.
Skeletal Adaptation To Reduced Mechanical Loading
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Author : Rachel Eliman
language : en
Publisher:
Release Date : 2014
Skeletal Adaptation To Reduced Mechanical Loading written by Rachel Eliman and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
Bone adapts its mass and architecture in response to its mechanical environment. Yet control of this process by mechanical cues is poorly understood, particularly for unloading. Defining the fundamental mechanoregulation of bone adaptation is critical for the better understanding and mitigation of bone loss in astronauts as well as clinical conditions such as spinal cord injury, stroke, muscular dystrophy, and bed rest. The overall goal of this work was to study skeletal adaptation to varying amounts of reduced loading to help delineate the relationship between mechanical stimuli and skeletal adaptation. We first examined the relative contribution of muscle and gravitational forces to the maintenance of skeletal health in mice, using botulinum toxin (BTX) to induce muscle paralysis and hindlimb unloading to eliminate external loading on the hindlimbs, alone and in combination. BTX led to greater bone loss than hindlimb unloading, while the combination of interventions led to the most detrimental effects overall, suggesting that both muscle and gravitational forces play a role in skeletal maintenance, with greater contributions from muscle forces. We then characterized skeletal adaptation to controlled reductions in mechanical loading of varying degrees employing a novel model that enables long-term exposure of mice to partial weightbearing (PWB). We found that declines in bone mass and architecture were linearly related to the degree of unloading. Even mice bearing 70% of their body weight exhibited significant bone loss, suggesting that the gravity of the moon (0.16 G) and Mars (0.38 G) will not be sufficient to prevent bone loss on future exploration missions. Finally, since bone remodeling is highly site-specific, we used gait analysis and inverse dynamics to determine the mechanical environment during PWB, and then developed a finite element model of the tibia to resolve the local strain-related stimulus proposed to drive changes in bone mass. We found modest correlations between cortical bone architecture at different PWB levels and strain energy density. Altogether this work provides a critical foundation and rationale for future studies that incorporate detailed quantification of the mechanical stimuli and longitudinal changes in bone architecture to further advance our understanding of the skeletal response to reduced loading.
Transactions Of The Annual Meeting Of The Orthopaedic Research Society
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Author : Orthopaedic Research Society. Meeting
language : en
Publisher:
Release Date : 2004
Transactions Of The Annual Meeting Of The Orthopaedic Research Society written by Orthopaedic Research Society. Meeting and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2004 with Orthopedics categories.
Consists of the transactions of the 22nd- annual meeting of the society.
Experimental And Computational Analysis Of Dynamic Loading For Bone Formation
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Author : Todd Randall Dodge
language : en
Publisher:
Release Date : 2013
Experimental And Computational Analysis Of Dynamic Loading For Bone Formation written by Todd Randall Dodge and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Biomechanics categories.
Bone is a dynamic tissue that is constantly remodeling to repair damage and strengthen regions exposed to loads during everyday activities. However, certain conditions, including long-term unloading of the skeleton, hormonal imbalances, and aging can disrupt the normal bone remodeling cycle and lead to low bone mass and osteoporosis, increasing risk of fracture. While numerous treatments for low bone mass have been devised, dynamic mechanical loading modalities, such as axial loading of long bones and lateral loading of joints, have recently been examined as potential methods of stimulating bone formation. The effectiveness of mechanical loading in strengthening bone is dependent both on the structural and geometric characteristics of the bone and the properties of the applied load. For instance, curvature in the structure of a bone causes bending and increased strain in response to an axial load, which may contribute to increased bone formation. In addition, frequency of the applied load has been determined to impact the degree of new bone formation; however, the mechanism behind this relationship remains unknown. In this thesis, the application of mechanical loading to treat osteoporotic conditions is examined and two questions are addressed: What role does the structural geometry of bone play in the mechanical damping of forces applied during loading? Does mechanical resonance enhance geometric effects, leading to localized areas of elevated bone formation dependent on loading frequency? Curvature in the structure of bone was hypothesized to enhance its damping ability and lead to increased bone formation through bending. In addition, loading at frequencies near the resonant frequencies of bone was predicted to cause increased bone formation, specifically in areas that experienced high principal strains due to localized displacements during resonant vibration. To test the hypothesis, mechanical loading experiments and simulations using finite element (FE) analysis were conducted to characterize the dynamic properties of bone. Results demonstrate that while surrounding joints contribute to the greatest portion of the damping capacity of the lower limb, bone absorbs a significant amount of energy through curvature-driven bending. In addition, results show that enhanced mechanical responses at loading frequencies near the resonant frequencies of bone may lead to increased bone formation in areas that experience the greatest principal strain during vibration. These findings demonstrate the potential therapeutic effects of mechanical loading in preventing costly osteoporotic fractures, and explore characteristics of bone that may lead to optimization of mechanical loading techniques. Further investigation of biomechanical properties of bone may lead to the prescribing of personalized mechanical loading treatments to treat osteoporotic diseases.
The Mechanical Adaptations Of Bones
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Author : John D. Currey
language : en
Publisher: Princeton University Press
Release Date : 2014-07-14
The Mechanical Adaptations Of Bones written by John D. Currey and has been published by Princeton University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-07-14 with Science categories.
This book relates the mechanical and structural properties of bone to its function in man and other vertebrates. John Currey, one of the pioneers of modern bone research, reviews existing information in the field and particularly emphasizes the correlation of the structure of bone with its various uses. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.
0704 Do Mechanical Strain Magnitude And Rate Drive Bone Adaptation In Adult Women A 12 Month Prospective Study
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Author :
language : en
Publisher:
Release Date : 2017
0704 Do Mechanical Strain Magnitude And Rate Drive Bone Adaptation In Adult Women A 12 Month Prospective Study written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
INTRODUCTION: Exercise-based interventions have long been considered a viable option for preserving and enhancing bone strength because bone adapts to best resist its habitual mechanical loading environment. However, it is not clear what specific mechanical factors govern the response. Animal in vivo loading models have demonstrated that mechanical signals related to strain magnitude and strain rate regulate bone adaptation. Despite extensive animal literature, the degree to which mechanical strain magnitude and rate govern bone adaptation in humans has never been prospectively tested. tOne major challenge is that bone strain is difficult to measure noninvasively. Our previously validated upper extremity loading model uses subject-specific finite element (FE) models and a well-controlled compressive load to generate known bone strains. In this model, an individual produces a voluntary compressive force through the radius by leaning onto the palm of the hand to achieve a target force. Feedback is given using a load cell, and individuals are given sound cues to assist in achieving a regular and consistent load/unload cycle. Instructions can manipulate loading rate.tHere, our purpose is to quantify the degree to which bone strain influences bone adaptation in the upper extremity of healthy adult women during a twelve month prospective study period. We hypothesized that (1) bone accrual is proportional to strain magnitude and strain rate, and (2) structural changes include increased cortical diameter and thickness, and increased trabecular bone mass near the endosteal surface.METHODS: One hundred and two healthy women age 21-40 were randomized to one of two experiments. Experiment 1: low (n=21) and high (n=24) strain magnitude. Experiment 2: low (n=21) and high (n=20) strain rate. Control group (n=16): no intervention. Potential subjects were screened for exclusion factors including oligomenorrhea (9 cycles/year), 25-hydroxyvitamin D serum
Multiscale Anabolic Bone Responses To Fluid Flow And Post Irradiation Loading
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Author : Peter Govey
language : en
Publisher:
Release Date : 2015
Multiscale Anabolic Bone Responses To Fluid Flow And Post Irradiation Loading written by Peter Govey and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
The long-term goal of this work is to reduce the burden of skeletal fractures by learning how to appropriate and guide the body's inherent capacity for adaptive bone formation. This tissue-level adaptation to mechanical load is the end product of bone cells responding to physical phenomena in their microscopic niche. Our objective was to elucidate if, and how, the initial stimulation of cells might ultimately bring about bone adaptation to strengthen bones at risk for fracture, specifically those damaged by radiation therapy. Our study followed that sequence: we first examined the response of osteocytic cells--those thought to orchestrate the adaptive response--to in vitro fluid flow simulating the physical stimulation present at the microscopic scale upon loading. We identified novel cell signaling using high-throughput analyses of the whole gene transcriptome and proteome, enriched by network mapping and functional association databases. These results implicated inflammatory cellular recruitment, most notably via up-regulation of stem cell homing chemokines Cxcl1 and Cxcl2. Therefore, we examined recruitment of cells to loaded bones as we progressed to the whole tissue scale of adaptation. First, in mice in vivo, we determined compression loading was best suited for examining both trabecular and cortical tibia bone adaptation since cantilever loading brought about trabecular bone loss. Importantly, compression loading attenuated bone loss, and even added additional new bone in mice modeling our at-risk population of irradiated bone marrow transplant recipients. Hence, we propose that cancer and transplant patients subject to similar therapies may also retain robust physiological capacity for load-induced bone adaptation to alleviate fracture risk. To unify these cell- and tissue-scale observations, we examined recruitment of transplanted donor cells. We found no up-regulation of donor cell proportions in marrow of loaded bones, but a non-significant trend toward increased donor cell presence in loaded bone itself. In sum, these findings lead us to propose that when irradiated bones are loaded, fluid flowed osteocytes signal for recruitment of marrow- or vasculature-derived osteoprogenitors, thereby increasing adaptive bone formation and fracture resistance.
Bone Adaptation In A Mouse Model Of Reduced Sensory Nerve Function
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Author : Mollie Alexandria Heffner
language : en
Publisher:
Release Date : 2016
Bone Adaptation In A Mouse Model Of Reduced Sensory Nerve Function written by Mollie Alexandria Heffner and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
Long bones are richly innervated with a presence of sensory neurons in the periosteum, cortical bone, endosteum and bone marrow. Emerging evidence suggests that these nerves are involved in more than simple pain transmission. Nerve damage not only affects bone during development, but also contributes to bone loss following injury. As bone cells express receptors for several neurotransmitters, nerves may regulate bone metabolism through local release of neuropeptides. The objective of this research was to elucidate the contribution of peripheral sensory nerves to bone adaptation. We used a chemical model of decreased nerve function, administering a naturally occurring compound, capsaicin, to neonatal mice. With the use of different imaging modalities and mechanical testing techniques, we assessed the effects of denervation on skeletal development. We next used a model of increased mechanical loading (tibial compression) to investigate how denervation alters the bone response to an anabolic stimulus. Finally, we measured changes in bone concentrations of neuropeptides CGRP and substance P in response to increased loading (tibial compression) and decreased loading (hindlimb unloading). Capsaicin treatment resulted in shorter femurs possessing thinner trabeculae. Denervation also altered the bone response to increased mechanical loading, with capsaicin-treated mice exhibiting greater changes in bone mass and mineral apposition rates. Neuropeptide concentrations were also changed by the mechanical environment with an increase in CGRP following tibial compression. Our findings indicate an important role for sensory nerves in bone metabolism, and suggest a potential target for therapeutics aimed at bone diseases characterized by abnormal bone formation.