Isolated effects of external bath osmolality, solute concentration, and electrical charge on solute transport across articular cartilage (original) (raw)
Related papers
Transport of neutral solute across articular cartilage: the role of zonal diffusivities
Journal of biomechanical engineering, 2015
Transport of solutes through diffusion is an important metabolic mechanism for the avascular cartilage tissue. Three types of inter-connected physical phenomena, namely mechanical, electrical, and chemical, are all involved in the physics of transport in cartilage. In this study, we use a carefully designed experimental-computational setup to separate the effects of mechanical and chemical factors from those of electrical charges. Axial diffusion of a neutral solute (Iodixanol) into cartilage was monitored using calibrated micro-CT images for up to 48 hours. A biphasic-solute computational model was fitted to the experimental data to determine the diffusion coefficients of cartilage. Cartilage was modeled either using one single diffusion coefficient (single-zone model) or using three diffusion coefficients corresponding to superficial, middle, and deep cartilage zones (multi-zone model). It was observed that the single-zone model cannot capture the entire concentration-time curve a...
Multi-scale imaging techniques to investigate solute transport across articular cartilage
Journal of Biomechanics, 2018
As articular cartilage is an avascular tissue, the transport of nutrients and cytokines through the tissue is essential for the health of cells, i.e. chondrocytes. Transport of specific contrast agents through cartilage has been investigated to elucidate cartilage quality. In laboratory, pre-clinical and clinical studies, imaging techniques such as magnetic imaging resonance (MRI), computed tomography (CT) and fluorescent microscopy have been widely employed to visualize and quantify solute transport in cartilage. Many parameters related to the physico-chemical properties of the solute, such as molecular weight, net charge and chemical structure, have a profound effect on the transport characteristics. Information on the interplay of the solute parameters with the imaging-dependent parameters (e.g. resolution, scan and acquisition time) could assist in selecting the most optimal imaging systems and data analysis tools in a specific experimental set up. Here, we provide a comprehensive review of various imaging systems to investigate solute transport properties in articular cartilage, by discussing their potentials and limitations. The presented information can serve as a guideline for applications in cartilage imaging and therapeutics delivery and to improve understanding of the setup of solute transport experiments in articular cartilage.
Neutral solute transport across osteochondral interface: A finite element approach
Journal of Biomechanics, 2016
Investigation of the solute transfer across articular cartilage and subchondral bone plate could nurture the understanding of the mechanisms of osteoarthritis (OA) progression. In the current study, we approached the transport of neutral solutes in human (slight OA) and equine (healthy) samples using both computed tomography and biphasic-solute finite element modeling. We developed a multi-zone biphasic-solute finite element model (FEM) accounting for the inhomogeneity of articular cartilage (superficial, middle and deep zones) and subchondral bone plate. Fitting the FEM model to the concentration-time curves of the cartilage and the equilibrium concentration of the subchondral plate/calcified cartilage enabled determination of the diffusion coefficients in the superficial, middle and deep zones of cartilage and subchondral plate. We found slightly higher diffusion coefficients for all zones in the human samples as compared to the equine samples. Generally the diffusion coefficient in the superficial zone of human samples was about 3-fold higher than the middle zone, the diffusion coefficient of the middle zone was 1.5-fold higher than that of the deep zone, and the diffusion coefficient of the deep zone was 1.5-fold higher than that of the subchondral plate/calcified cartilage. Those ratios for equine samples were 9, 2 and 1.5, respectively. Regardless of the species considered, there is a gradual decrease of the diffusion coefficient as one approaches the subchondral plate, whereas the rate of decrease is dependent on the type of species.
2019
The transport and distribution of charged molecules in polyelectrolyte solutions are of both fundamental and practical importance. A practical example, which is the specific subject addressed in the present paper, is the transport and distribution of charged species into cartilage. The charged species could be a contrast agent or a drug molecule involved in diagnosis or treatment of the widespread degenerative disease osteoarthritis, which leads to degradation of articular cartilage. Associated scientific issues include the rate of transport and the equilibrium concentrations of the charged species in the cartilage and the synovial fluid. To address these questions, we present results from magnetic resonance micro-imaging experiments on a model system of articular cartilage. The experiments yield temporally and spatially resolved data on the transport of a negatively charged contrast agent (charge = −2), used in medical examinations of cartilage, into a polyelectrolyte solution, whi...
Archives of Biochemistry and Biophysics, 1996
Articular cartilage provides a low-friction wear-resis-We have studied the contributions of diffusion, fluid tant bearing surface that distributes and transmits flow and electrical migration to molecular transport loads to the underlying bone. The ability of cartilage through adult articular cartilage explants using neuto withstand compressive, tensile, and shear forces is tral and charged solutes that were either radiolabeled dependent on the composition and structural integrity ( 3 H 2 O, [ 35 S]sulfate, [ 3 H]thymidine, [ 3 H]raffinose, and a of the extracellular matrix (ECM). 2 The chondrocytes synthetic matrix metalloproteinase inhibitor) or fluoin cartilage maintain the mechanically functional ECM rescently tagged (NSPA and Lissamine-dextran). In orby regulating synthesis and degradation of the matrix der to induce fluid flow within the cartilage matrix components including proteoglycans (PG), collagen fiwithout mechanical deformation, electric current denbrils, as well as other proteins and glycoproteins. sities were applied across cartilage disks. These cur-Solute transport through the cartilage matrix plays rents produced electroosmotic fluid velocities of 1-2 a significant role in the ability of chondrocytes to mainmm/s, magnitudes that have been reported to exist durtain the biochemical and mechanical integrity of cartiing joint loading in vivo. This fluid convection enlage. Although there is no vascular or lymphatic system hanced neutral solute flux relative to passive diffusion in adult cartilage to provide nutrient delivery and alone by a factor that increased with the size of the waste product removal, the tissue is metabolically acsolute. While the enhancement factor for 3 H 2 O was 2.3tive and a coordinated synthesis, assembly, and turn-
Magnetic resonance microscopy studies of cation diffusion in cartilage
Biochimica et Biophysica Acta (BBA) - General Subjects, 1997
The diffusion of copper ions in bovine nasal cartilage BNC , a dense connective tissue, was investigated to further the understanding of ion transport in charged biopolymer systems. Using an inversion-recovery null-point imaging technique, it was found that the diffusion rate of divalent copper ions into cartilage was significantly lower in normal BNC than in BNC in which the matrix fixed charges had been reduced by enzymatic digestion or acid neutralization. In normal cartilage, counterion diffusion was not well described by a simple Fickian process, likely owing to the high charge density of the constituent molecules. In contrast, in both digested and acid neutralized BNC, counterion diffusion appeared Fickian. Features of the ion transport process were modeled using a diffusion equation which included a linear sorption term to account for cation binding. The diffusion coefficient of copper in cartilage increased with decreasing matrix fixed charge and was constant for reservoir concentrations up to 30 mM. The activation energy for the diffusion of copper into BNC was determined to be 34.5 kJrmol.
Journal of Biomechanics, 2017
Cross-talk of subchondral bone and articular cartilage could be an important aspect in the etiology of osteoarthritis. Previous research has provided some evidence of transport of small molecules (~370 Da) through the calcified cartilage and subchondral bone plate in murine osteoarthritis models. The current study, for the first time, uses a neutral diffusing computed tomography (CT) contrast agent (iodixanol, ~1550 Da) to study the permeability of the Keywords osteochondral interface, micro-computed tomography, iodixanol diffusion, subchondral plate thickness and porosity, articular cartilage, osteoarthritis
Transport properties of cartilaginous tissues
Current rheumatology reviews, 2009
Cartilaginous tissues, such as articular cartilage and intervertebral disc, are avascular tissues which rely on transport for cellular nutrition. Comprehensive knowledge of transport properties in such tissues is therefore necessary in the understanding of nutritional supply to cells. Furthermore, poor cellular nutrition in cartilaginous tissues is believed to be a primary source of tissue degeneration, which may result in osteoarthritis (OA) or disc degeneration. In this mini-review, we present an overview of the current status of the study of transport properties and behavior in cartilaginous tissues. The mechanisms of transport in these tissues, as well as experimental approaches to measuring transport properties and results obtained are discussed. The current status of bioreactors used in cartilage tissue engineering is also presented.