Computer Simulation of Human Mandibular Bone Structure by iBone, a Novel Reaction-Diffusion Bone Remodeling Model

2006 ◽  
Vol 306-308 ◽  
pp. 1277-1282
Author(s):  
Ken-Ichi Tezuka ◽  
Akiyuki Takahashi ◽  
Tomoko Takeda ◽  
Yoshitaka Wada ◽  
Masanori Kikuchi
Keyword(s):  
Computer Simulation ◽  
Bone Remodeling ◽  
Bone Structure ◽  
Bone Cells ◽  
Physiological State ◽  
Three Dimensional ◽  
Reaction Diffusion ◽  
Ct Images ◽  
Mandibular Bone ◽  
Left Group

Bone is a complex system with adaptation and repair functions. To understand how bone cells can create a structure adapted to the mechanical environment, we proposed a simple bone remodeling model, iBone, based on a reaction-diffusion system [1]. A 3-dimensional mandibular bone model consisting of approximately 1.4 million elements was constructed from sequential computer tomography (CT) images of a 14-year old female. Both teeth and bone were modeled with isoparametric voxel elements with Young's Modulus = 20 GPa and Poisson's ratio = 0.3. Both heads of the mandible were fixed allowing rotation and horizontal movement. Teeth were fixed vertically allowing horizontal movements. Incisor, right/left group, and right/left molar biting conditions were simulated. The locations and directions of muscles, and their forces were predicted from the CT images. Remodeling simulation was performed by 10 sets of finite element method analysis and reaction-diffusion remodeling simulation to obtain internal structure adapted to each loading condition. As a result, the major part of the corpus of the simulated mandibular bone showed similar internal structures under different biting conditions. Moreover, these simulated structures were satisfactorily similar to that of the real mandible. Computer simulation of three-dimensional bone structures based on CT images will be very useful for understanding the patho-physiological state of bone under various mechanical conditions, and may assist orthopedic doctors to predict the risk and efficacy of surgical therapies.

scholarly journals Energy Metabolism of Bone

2017 ◽  
Vol 45 (7) ◽  
pp. 887-893 ◽  
Author(s):  
Katherine J. Motyl ◽  
Anyonya R. Guntur ◽  
Adriana Lelis Carvalho ◽  
Clifford J. Rosen
Keyword(s):  
Bone Remodeling ◽  
Energy Homeostasis ◽  
Bone Structure ◽  
Bone Cells ◽  
Bone Cell ◽  
Whole Body ◽  
Blood Calcium ◽  
Micro Cracks ◽  
Intimate Link ◽  
Body Energy

Biological processes utilize energy and therefore must be prioritized based on fuel availability. Bone is no exception to this, and the benefit of remodeling when necessary outweighs the energy costs. Bone remodeling is important for maintaining blood calcium homeostasis, repairing micro cracks and fractures, and modifying bone structure so that it is better suited to withstand loading demands. Osteoclasts, osteoblasts, and osteocytes are the primary cells responsible for bone remodeling, although bone marrow adipocytes and other cells may also play an indirect role. There is a renewed interest in bone cell energetics because of the potential for these processes to be targeted for osteoporosis therapies. In contrast, due to the intimate link between bone and energy homeostasis, pharmaceuticals that treat metabolic disease or have metabolic side effects often have deleterious bone consequences. In this brief review, we will introduce osteoporosis, discuss how bone cells utilize energy to function, evidence for bone regulating whole body energy homeostasis, and some of the unanswered questions and opportunities for further research in the field.

Structural Topology Optimization Method Based on Bone Remodeling

2013 ◽  
Vol 423-426 ◽  
pp. 1813-1818
Author(s):  
Kaysar Rahman ◽  
Nurmamat Helil ◽  
Rahmatjan Imin ◽  
Mamtimin Geni
Keyword(s):  
Topology Optimization ◽  
Bone Remodeling ◽  
Bone Structure ◽  
Reaction Diffusion ◽  
Optimization Method ◽  
Mechanical Stimulus ◽  
Bone Adaptation ◽  
Reaction Diffusion Equations ◽  
Structural Topology Optimization ◽  
Structural Topology

Bone is a dynamic living tissue that undergoes continuous adaptation of its mass and structure in response to mechanical and biological environment demands. In this paper, we firstly propose a mathematical model based on cross-type reaction diffusion equations of bone adaptation during a remodeling cycle due to mechanical stimulus. The model captures qualitatively very well the bone adaptation and cell interactions during the bone remodeling. Secondly assuming the bone structure to be a self-optimizing biological material which maximizes its own structural stiffness, bone remodeling model coupled with finite element method by using the add and remove element a new topology optimization of continuum structure is presented. Two Numerical examples demonstrate that the proposed approach greatly improves numerical efficiency, compared with the others well known methods for structural topology optimization in open literatures.

scholarly journals Development of 3D CAD/FEM Analysis System for Natural Teeth and Jaw Bone Constructed from X-Ray CT Images

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Aki Hasegawa ◽  
Akikazu Shinya ◽  
Yuji Nakasone ◽  
Lippo V. J. Lassila ◽  
Pekka K. Vallittu ◽  
...  
Keyword(s):  
Finite Element ◽  
Bone Structure ◽  
Three Dimensional ◽  
Fem Analysis ◽  
Element Model ◽  
Ct Images ◽  
3D Cad ◽  
Dimensional Finite Element ◽  
Analysis System ◽  
Three Dimensional Finite Element

A three-dimensional finite element model of the lower first premolar, with the three layers of enamel, dentin, and pulp, and the mandible, with the two layers of cortical and cancellous bones, was directly constructed from noninvasively acquired CT images. This model was used to develop a system to analyze the stresses on the teeth and supporting bone structure during occlusion based on the finite element method and to examine the possibility of mechanical simulation.

Conformational characterization of nucleosome structure by Electron Microscopy

1993 ◽  
Vol 51 ◽  
pp. 194-195
Author(s):  
Gregory J. Czarnota
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Physiological State ◽  
Gene Activation ◽  
Three Dimensional ◽  
Macromolecular Complex ◽  
Ultrastructural Studies ◽  
Ionic Environment ◽  
Nucleosome Structure ◽  
Dimensional Reconstruction

Chromatin structure at the fundamental level of the nucleosome is important in vital cellular processes. Recent biochemical and genetic analyses show that nucleosome structure and structural changes are very active participants in gene expression, facilitating or inhibiting transcription and reflecting the physiological state of the cell. Structural states and transitions for this macromolecular complex, composed of DNA wound about a heterotypic octamer of variously modified histone proteins, have been measured by physico-chemical techniques and by enzyme-accessibility and are recognized to occur with various post-translational modifications, gene activation, transformation and with ionic-environment. In spite of studies which indicate various forms of nucleosome structure, all current x-ray and neutron diffraction studies have consistently resulted in only one structure, suggestive of a static conformation. In contrast, two-dimensional electron microscopy studies and three-dimensional reconstruction techniques have yielded different structures. These fundamental differences between EM and other ultrastructural studies have created a long standing quandary, which I have addressed and resolved using spectroscopic electron microscopy and statistical analyses of nucleosome images in a study of nucleosome structure with ionic environment.

scholarly journals Renal Proximal Tubule Cell Cannabinoid-1 Receptor Regulates Bone Remodeling and Mass via a Kidney-to-Bone Axis

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 414
Author(s):  
Saja Baraghithy ◽  
Yael Soae ◽  
Dekel Assaf ◽  
Liad Hinden ◽  
Shiran Udi ◽  
...  
Keyword(s):  
Bone Mass ◽  
Proximal Tubule ◽  
Bone Remodeling ◽  
Kidney Function ◽  
Bone Cells ◽  
Critical Role ◽  
Renal Proximal Tubule ◽  
Proximal Tubule Cell ◽  
Protective Effects ◽  
Cannabinoid 1 Receptor

The renal proximal tubule cells (RPTCs), well-known for maintaining glucose and mineral homeostasis, play a critical role in the regulation of kidney function and bone remodeling. Deterioration in RPTC function may therefore lead to the development of diabetic kidney disease (DKD) and osteoporosis. Previously, we have shown that the cannabinoid-1 receptor (CB1R) modulates both kidney function as well as bone remodeling and mass via its direct role in RPTCs and bone cells, respectively. Here we employed genetic and pharmacological approaches that target CB1R, and found that its specific nullification in RPTCs preserves bone mass and remodeling both under normo- and hyper-glycemic conditions, and that its chronic blockade prevents the development of diabetes-induced bone loss. These protective effects of negatively targeting CB1R specifically in RPTCs were associated with its ability to modulate erythropoietin (EPO) synthesis, a hormone known to affect bone mass and remodeling. Our findings highlight a novel molecular mechanism by which CB1R in RPTCs remotely regulates skeletal homeostasis via a kidney-to-bone axis that involves EPO.

scholarly journals Pathogenic variants in GNPTAB and GNPTG encoding distinct subunits of GlcNAc-1-phosphotransferase differentially impact bone resorption in patients with mucolipidosis type II and III

2021 ◽  
Author(s):  
Giorgia Di Lorenzo ◽  
Lena M. Westermann ◽  
Timur A. Yorgan ◽  
Julian Stürznickel ◽  
Nataniel F. Ludwig ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Remodeling ◽  
Bone Cells ◽  
Collagen Crosslinks ◽  
Clinical Criteria ◽  
Pathogenic Variants ◽  
Bone Biopsies ◽  
Appropriate Therapy ◽  
Alpha Beta ◽  
Deficient Mice

Abstract Purpose Pathogenic variants in GNPTAB and GNPTG, encoding different subunits of GlcNAc-1-phosphotransferase, cause mucolipidosis (ML) II, MLIII alpha/beta, and MLIII gamma. This study aimed to investigate the cellular and molecular bases underlying skeletal abnormalities in patients with MLII and MLIII. Methods We analyzed bone biopsies from patients with MLIII alpha/beta or MLIII gamma by undecalcified histology and histomorphometry. The skeletal status of Gnptgkoand Gnptab-deficient mice was determined and complemented by biochemical analysis of primary Gnptgko bone cells. The clinical relevance of the mouse data was underscored by systematic urinary collagen crosslinks quantification in patients with MLII, MLIII alpha/beta, and MLIII gamma. Results The analysis of iliac crest biopsies revealed that bone remodeling is impaired in patients with GNPTAB-associated MLIII alpha/beta but not with GNPTG-associated MLIII gamma. Opposed to Gnptab-deficient mice, skeletal remodeling is not affected in Gnptgko mice. Most importantly, patients with variants in GNPTAB but not in GNPTG exhibited increased bone resorption. Conclusion The gene-specific impact on bone remodeling in human individuals and in mice proposes distinct molecular functions of the GlcNAc-1-phosphotransferase subunits in bone cells. We therefore appeal for the necessity to classify MLIII based on genetic in addition to clinical criteria to ensure appropriate therapy.

scholarly journals The Development of Molecular Biology of Osteoporosis

2021 ◽  
Vol 22 (15) ◽  
pp. 8182
Author(s):  
Yongguang Gao ◽  
Suryaji Patil ◽  
Jingxian Jia
Keyword(s):  
Bone Resorption ◽  
Molecular Biology ◽  
Bone Formation ◽  
Bone Mass ◽  
Bone Remodeling ◽  
Bone Cells ◽  
Cell Activity ◽  
Bone Cell ◽  
Bone Disorders ◽  
Molecular Aspects

Osteoporosis is one of the major bone disorders that affects both women and men, and causes bone deterioration and bone strength. Bone remodeling maintains bone mass and mineral homeostasis through the balanced action of osteoblasts and osteoclasts, which are responsible for bone formation and bone resorption, respectively. The imbalance in bone remodeling is known to be the main cause of osteoporosis. The imbalance can be the result of the action of various molecules produced by one bone cell that acts on other bone cells and influence cell activity. The understanding of the effect of these molecules on bone can help identify new targets and therapeutics to prevent and treat bone disorders. In this article, we have focused on molecules that are produced by osteoblasts, osteocytes, and osteoclasts and their mechanism of action on these cells. We have also summarized the different pharmacological osteoporosis treatments that target different molecular aspects of these bone cells to minimize osteoporosis.

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