Effects of Compression on Glucose Consumption in Intervertebral Disc

2008 ◽  
Author(s):  
Chun-Yuh Huang ◽  
Wei Yong Gu
Keyword(s):  
Intervertebral Disc ◽  
Theoretical Study ◽  
Mixture Theory ◽  
Glucose Consumption ◽  
Nutrient Level ◽  
Metabolic Rates ◽  
Unconfined Compression ◽  
Theoretical Formulation ◽  
Tissue Integrity ◽  
Cartilaginous Tissues

Nutrition supply is a concern for the health of avascular cartilaginous tissues such as intervertebral disc (IVD). Maintaining tissue integrity relies on cellular biosynthesis of extracellular matrix, which is an energy demanding process [1]. In the IVD, energy is mainly generated through glycolysis (i.e., glucose consumption). Metabolism of nutrients (e.g., oxygen and glucose) within the IVD depends on local concentrations of nutrients, and coupling effects between nutrient level and metabolic rate [2,3]. Our previous theoretical study had developed a new theoretical formulation by incorporating the metabolic rates of solutes into the mechano-electrochemical mixture theory [4,5]. By using this new theoretical model, the distribution of oxygen and lactate can be predicted within the IVD under static and dynamics compressions [4]. However, the effect of compression on glucose consumption in the IVD has not been studied. The objective of this study was to examine the effects of compression on glucose consumption in the IVD under static and dynamic unconfined compression numerically.

Distribution of Oxygen, Glucose and Lactate in Degenerated Intervertebral Disc

2009 ◽  
Author(s):  
Chun-Yuh Huang ◽  
Wei Yong Gu
Keyword(s):  
Elastic Modulus ◽  
Intervertebral Disc ◽  
Mechanical Loading ◽  
Material Properties ◽  
Mixture Theory ◽  
Unconfined Compression ◽  
Fixed Charge Density ◽  
Tissue Degeneration ◽  
Solute Diffusivity ◽  
Diffusion And Convection

Poor nutritional supply has been a major concern for the health of intervertebral disc (IVD) since the IVD is the largest avascular tissue in the human body. The transport of vital nutrients to cells relies on diffusion and convection through the extracellular matrix (ECM) in the IVD. Transport and metabolism of nutrients (e.g., oxygen and glucose) within the IVD depend on many factors, including the material properties of ECM (e.g., permeability, elastic modulus, and solute diffusivity), cellular metabolic rates, nutritional supply at the edge of the IVD, and mechanical loading [1–6]. Tissue degeneration alters the material properties of the IVD, such as an increase in elastic modulus and a decrease in water content, fixed charge density, permeability and solute diffusivity [6]. However, the effect of tissue degeneration on transport and metabolism of nutrients in the IVD under mechanical loading has not been elucidated. The objective of this study was to numerically investigate the distribution of glucose, oxygen and lactate in the degenerated IVD under static unconfined compression using the mechano-electrochemical mixture theory [7].

Effects of Compression on Distributions of Oxygen and Lactate in Intervertebral Disc

2007 ◽  
Author(s):  
Chun-Yuh Huang ◽  
Wei Yong Gu
Keyword(s):  
Intervertebral Disc ◽  
Theoretical Study ◽  
Dynamic Compression ◽  
Nutrient Supply ◽  
Theoretical Studies ◽  
Cartilaginous Tissue ◽  
Unconfined Compression ◽  
Solute Fluxes ◽  
Triphasic Theory ◽  
New Formulation

Since the intervertebral disc (IVD) is the largest avascular cartilaginous structure in the human body, poor nutrient supply has been suggested as a potential mechanism for disc degeneration. The previous theoretical studies have shown that the distributions of nutrients and metabolites (e.g., oxygen, glucose, and lactate) within the IVD depended on tissue diffusivities, nutrient supply, cellular metabolic rates, and coupling effects between nutrient and metabolite [1,2]. Our recent theoretical study suggested that dynamic compression can promote transport of neutral solute in the anisotropic cartilaginous tissue by enhancing both diffusive and convective solute fluxes [3]. However, the effect of compression on distributions of nutrients and metabolites in the IVD has not been studied. The objective of this study was to examine the effects of compression on distributions of oxygen and lactate in the IVD under static and dynamic unconfined compression using a new formulation of the triphasic theory.

Multiphasic Finite Element Analysis of Physical Signals and Solute Transport in the Human Intervertebral Disc

2004 ◽  
Author(s):  
Hai Yao ◽  
Wei Yong Gu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Soft Tissue ◽  
Intervertebral Disc ◽  
Mixture Theory ◽  
Element Model ◽  
Tissue Composition ◽  
Element Analysis ◽  
3D Finite Element ◽  
Disc Nutrition

A 3D finite element model for charged hydrated soft tissue containing charged/uncharged solutes was developed based on the multi-phasic mechano-electrochemical mixture theory [1–2]. This model was applied to analyze the mechanical, chemical and electrical signals within the human intervertebral disc under mechanical loading. The effects of tissue composition and material property on the physical signals and the transport of fluid, ions and nutrients were investigated. This study is important for understanding disc biomechanics, disc nutrition and disc mechanobiology.

Deformation of the Extracellular Matrix Due to Osmotic Pressure in Cartilaginous Tissues

2010 ◽  
Vol 93-94 ◽  
pp. 243-246
Author(s):  
Boonyong Punantapong
Keyword(s):  
Extracellular Matrix ◽  
Osmotic Pressure ◽  
Preferential Flow ◽  
Soft Tissues ◽  
Analytic Solutions ◽  
Tissue Integrity ◽  
Cartilaginous Tissues ◽  
External Pressures ◽  
Field Fluctuations ◽  
Constrained Deformation

This study is to characterize and estimate preferential flow and solute transport in soft tissue. In soft tissues, large molecules such as proteoglycans trapped in the extracellular matrix generate high levels of osmotic pressure to counter balance external pressures. The semi-permeable matrix and fixed negative charges on these molecules serve to promote the swelling and collapse behaviour of cartilaginous tissues when there is an imbalance of molecular concentrations. At the same time, the collagen fibres were a network of stretch-resistant matrix, which prevents tissue from over-swelling and keeps tissue integrity. Therefore, a simplified mathematical model is proposed, and implemented in the finite element method. Analytic solutions for solute distribution in the extracellular matrix were derived by solving under loading conditions. The results were found that the estimate with field fluctuations led to the numerical results in most cases, and significant differences were only found under conditions of highly constrained deformation.

scholarly journals Glucose Metabolic Rate Kinetic Model Parameter Determination in Humans: The Lumped Constants and Rate Constants for [18F]Fluorodeoxyglucose and [11C]Deoxyglucose

1985 ◽  
Vol 5 (2) ◽  
pp. 179-192 ◽  
Author(s):  
M. Reivich ◽  
A. Alavi ◽  
A. Wolf ◽  
J. Fowler ◽  
J. Russell ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Metabolic Rate ◽  
Rate Constants ◽  
Glucose Consumption ◽  
Normal Subjects ◽  
Parameter Determination ◽  
Metabolic Rates ◽  
Mean Values ◽  
Glucose Metabolic Rate ◽  
The Mean

The rate constants and lumped constants (LCs) for [18F]fluorodeoxyglucose ([18F]FDG) and [11C]deoxyglucose ([11C]DG) were determined in humans for the glucose metabolic rate kinetic model used to measure local cerebral glucose consumption. The mean values (±SE) of the LCs for [18F]FDG and [11C]DG are 0.52 ± 0.028 (n = 9) and 0.56 ± 0.043 (n = 6), respectively. The mean values (±SE) of the rate constants k*1, k*2, k*3, and k*4 for [18F]FDG for gray matter are 0.095 ± 0.005, 0.125 ± 0.002, 0.069 ± 0.002, and 0.0055 ± 0.0003, respectively. The corresponding values for white matter are 0.065 ± 0.005, 0.126 ± 0.003, 0.066 ± 0.002, and 0.0054 ± 0.0006, respectively. Using these values and previously published values for the rate constants for [11C]DG, the average whole-brain metabolic rates for glucose in normal subjects measured with [18F]FDG and [11C]DG are 5.66 ± 0.37 (n = 6) and 4.99 ± 0.23 (n = 6) mg/100 g/min, respectively. These values are not significantly different ( t = 1.56, p > 0.10) and agree well with reported values in the literature determined by means of the Kety-Schmidt technique.

New Method for the Determination of the Diffusion Tensor of Solutes in Tissues by FRAP Technique

2008 ◽  
Author(s):  
Francesco Travascio ◽  
Weiyong Gu
Keyword(s):  
Intervertebral Disc ◽  
Transport Mechanism ◽  
Diffusion Tensor ◽  
New Method ◽  
Cartilaginous Tissues

Diffusion is an important transport mechanism for nutrition supply into avascular cartilaginous tissues, such as intervertebral disc [1].

Analysis of Solute Transport in Cartilaginous Tissue Under Dynamic Unconfined Compression

2003 ◽  
Author(s):  
Hai Yao ◽  
Wei Yong Gu
Keyword(s):  
Dynamic Compression ◽  
Electrical Potential ◽  
Loading Frequency ◽  
Mechanical Forces ◽  
The Finite Element Method ◽  
Unconfined Compression ◽  
Cartilage Sample ◽  
Cartilaginous Tissues ◽  
Transduction Mechanisms ◽  
Theoretical Analyses

Transport of fluid and solutes through the extracellular matrix plays a key role in the nutrition and growth of cartilaginous tissues that lack blood supply. It has been found that the mechanical loading can alter the transport rates of solutes within cartilage [Bonassar, 2000; O’Hara, 1990; Quinn, 2002]. Dynamic compression may enhance the transport of large solutes (e.g., growth factors) within the tissue. Many theoretical analyses have been reported in literature on the transport of fluid and solutes, as well as physical signals (stress, strain, pressure, concentrations, and electrical potential) in cartilage under unconfined compression [Armstrong, 1984; Levenston, 1999; Mow, 2002]. However, little is known as to how the tissue fixed charge density (FCD) affects the transport of fluid and neutral solutes (e.g., glucose and IGF-1) in cartilage sample in dynamic compression. In this study, we numerically analyzed the transport of fluid and solutes, as well as the mechano-electrochemical signals within the cartilage sample in dynamic unconfined compression, using the finite element method (FEM). The objective of this study was to investigate the effects of FCD, loading frequency, and loading platens (permeable vs. impermeable) on the transport of fluid, ions, and neutral solutes within cartilage. This study is essential for the understanding of tissue nutrition and signal transduction mechanisms in cartilage subjected to mechanical forces.

scholarly journals A Growth Mixture Theory for Cartilage

2000 ◽  
Author(s):  
Stephen M. Klisch ◽  
Robert L. Sah ◽  
Anne Hoger
Keyword(s):  
Mixture Theory ◽  
Solid Matrix ◽  
Inviscid Fluid ◽  
Elastic Materials ◽  
Internal Constraints ◽  
Volumetric Growth ◽  
Cartilage Growth ◽  
Cartilaginous Tissues ◽  
Growth Mixture ◽  
Developmental Growth

Abstract In this paper we present a model of growth for cartilaginous tissues in which there exists a saturated solid matrix composed of multiple constituents that may grow and remodel independently of each other. Klisch and Hoger recently developed a general theory of volumetric growth for a mixture of ν−1 growing elastic materials and an inviscid fluid, which included a treatment of two special types of internal constraints that are relevant to cartilage. Here, that theory is specialized to construct a cartilage growth model. This theory allows the constituents of the solid matrix to grow independently of each other, and can model the evolution of the constituent pre-stresses and the tissue’s mechanical properties during developmental growth and degeneration. A simple example is presented which illustrates these features of the theory.

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