Depth Dependent Diffusivity Profile in Bovine Articular Cartilage: Comparing Transverse and Axial Diffusivities

2007 ◽  
Author(s):  
Onyi N. Irrechukwu ◽  
Marc E. Levenston
Keyword(s):  
Extracellular Matrix ◽  
Articular Cartilage ◽  
Articular Surface ◽  
Deep Zone ◽  
Superficial Zone ◽  
Transport Pathway ◽  
Bovine Articular Cartilage ◽  
Extracellular Matrix Components ◽  
Matrix Components ◽  
Oriented Parallel

As articular cartilage is avascular, diffusion at a tissue length scale is the primary mode of solute and nutrient transport to its cells. The major extracellular matrix components are water (70–80%), chondrocytes, collagen (10–20%) and proteoglycans (5–10%) bearing sulfated glycosaminoglycans (GAG) [1]. Electron microscopy studies have shown that articular cartilage can be regarded as having three separate structural zones — superficial, middle and deep. The proportions of the various matrix components vary from the surface to the deep zone in any given joint and the greatest variations in content occur in the GAG content [2]. In addition the collagen fiber alignment varies, with fibers oriented parallel to the articular surface in the superficial zone, randomly oriented in the middle zone and oriented perpendicular to the surface in the deep zone. To a large extent, it is the spatially inhomogeneous composition of articular cartilage and microstructural orientation of its extracellular matrix components that determines the tortuosity of the transport pathway [3]. We therefore hypothesized that the diffusivity profile of a solute through the cartilage depth is inversely related to the GAG content and that the ratio between the axial and lateral diffusivities within each cartilage zone is related to the degree of anisotropy within the zone.

A Fibril Reinforced Poroelastic Model of Articular Cartilage Including Depth Dependent Material Properties

1999 ◽  
Author(s):  
L. P. Li ◽  
M. D. Buschmann ◽  
A. Shirazi-Adl
Keyword(s):  
Articular Cartilage ◽  
Regional Differences ◽  
Articular Surface ◽  
Collagen Fibrils ◽  
Superficial Zone ◽  
Cartilage Surface ◽  
Poroelastic Model ◽  
Oriented Parallel ◽  
Strain Dependent ◽  
Very High

Abstract Articular cartilage is a highly nonhomogeneous, anisotropic and multiphase biomaterial consisting of mainly collagen fibrils, proteoglycans and water. Noncalcified cartilage is morphologically divided into three zones along the depth, i.e. superficial, transitional and radial zones. The thickness, density and alignment of collagen fibrils vary from the superficial zone, where fibrils are oriented parallel to the articular surface, to the radial zone where fibrils are perpendicular to the boundary between bone, and cartilage. The concentration of proteoglycans increases with the depth from the cartilage surface. These regional differences have significant implications to the mechanical function of joints, which is to be explored theoretically in the present work by considering inhomogeneity along the cartilage depth. A nonlinear fibril reinforced poroelastic model is employed as per Li et al. (1999) in which the collagen fibrils were modeled as a distinct constituent whose tensile stiffness was taken to be very high and be strain dependent but whose compressive stiffness was neglected.

scholarly journals Alterations of Extracellular Matrix Components in the Course of Juvenile Idiopathic Arthritis

Metabolites ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 132
Author(s):  
Magdalena Wojdas ◽  
Klaudia Dąbkowska ◽  
Katarzyna Winsz-Szczotka
Keyword(s):  
Extracellular Matrix ◽  
Juvenile Idiopathic Arthritis ◽  
Articular Cartilage ◽  
Connective Tissue Diseases ◽  
Diagnostic Tools ◽  
Radiographic Imaging ◽  
Extracellular Matrix Components ◽  
Common Group ◽  
Matrix Components ◽  
And Function

Juvenile idiopathic arthritis (JIA) is the most common group of chronic connective tissue diseases in children that is accompanied by joint structure and function disorders. Inflammation underlying the pathogenic changes in JIA, caused by hypersecretion of proinflammatory cytokines, leads to the destruction of articular cartilage. The degradation which progresses with the duration of JIA is not compensated by the extent of repair processes. These disorders are attributed in particular to changes in homeostasis of extracellular matrix (ECM) components, including proteoglycans, that forms articular cartilage. Changes in metabolism of matrix components, associated with the disturbance of their degradation and biosynthesis processes, are the basis of the progressive wear of joint structures observed in the course of JIA. Clinical evaluation and radiographic imaging are current methods to identify the destruction. The aim of this paper is to review enzymatic and non-enzymatic factors involved in catabolism of matrix components and molecules stimulating their biosynthesis. Therefore, we discuss the changes in these factors in body fluids of children with JIA and their potential diagnostic use in the assessment of disease activity. Understanding the changes in ECM components in the course of the child-hood arthritis may provide the introduction of both new diagnostic tools and new therapeutic strategies in children with JIA.

scholarly journals Localization of proteoglycan monomer and link protein in the matrix of bovine articular cartilage: An immunohistochemical study.

1980 ◽  
Vol 28 (7) ◽  
pp. 621-635 ◽  
Author(s):  
A R Poole ◽  
I Pidoux ◽  
A Reiner ◽  
L H Tang ◽  
H Choi ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Articular Surface ◽  
Guanidine Hydrochloride ◽  
Cartilage Matrix ◽  
Binding Studies ◽  
Superficial Zone ◽  
Surface Culture ◽  
Bovine Articular Cartilage ◽  
Link Protein ◽  
The Matrix

Using monospecific antisera and immunofluorescence microscopy, proteoglycan monomer (PG), and link proteins were demonstrated throughout the extracellular matrix of bovine articular cartilage. A narrow band of strong pericellular staining was usually observed for both molecules, indicating a pericellular concentration of proteoglycan monomer: this conclusion was supported by dye-binding studies. Whereas PG was evenly distributed throughout the remaining matrix, more link protein was detectable in interterritorial sites in middle and deep zones. Well-defined zones of weaker territorial staining for link protein stained strongest for chondroitin sulfate. Trypsin treatment of cartilage resulted in a loss of most of the PG staining, but some selective retention of link protein, particularly around chondrocytes in the superficial zone at and near the articular surface. This residual staining was largely removed if sections were fixed after chondroitinase treatment. After extraction of cartilage with 4M guanidine hydrochloride, only PG remained and this was concentrated in the superficial zone. These observations are shown to support the concept of aggregation of PG and link protein with hyaluronic acid (HA) in cartilage matrix, and the binding of PG and link protein to HA, which is attached to the chondrocyte surface. Culture of cartilage depleted of PG and link protein by trypsin demonstrated that individual chondrocytes can secrete both PG and link proteins and that the organization of cartilage matrix can be regenerated in part over a period of 4 days.

scholarly journals Genipin crosslinked chitosan/PEO nanofibrous scaffolds exhibiting an improved microenvironment for the regeneration of articular cartilage

2021 ◽  
pp. 088532822110020
Author(s):  
Kuan Yong Ching ◽  
Orestis Andriotis ◽  
Bram Sengers ◽  
Martin Stolz
Keyword(s):  
Extracellular Matrix ◽  
Articular Cartilage ◽  
Articular Chondrocytes ◽  
Immunohistochemical Analysis ◽  
Chitosan Solution ◽  
Deep Zone ◽  
Superficial Zone ◽  
Fibril Structure ◽  
Nanofibrous Scaffolds ◽  
Poly Ethylene

Towards optimizing the growth of extracellular matrix to produce repair cartilage for healing articular cartilage (AC) defects in joints, scaffold-based tissue engineering approaches have recently become a focus of clinical research. Scaffold-based approaches by electrospinning aim to support the differentiation of chondrocytes by providing an ultrastructure similar to the fibrillar meshwork in native cartilage. In a first step, we demonstrate how the blending of chitosan with poly(ethylene oxide) (PEO) allows concentrated chitosan solution to become electrospinnable. The chitosan-based scaffolds share the chemical structure and characteristics of glycosaminoglycans, which are important structural components of the cartilage extracellular matrix. Electrospinning produced nanofibrils of ∼100 nm thickness that are closely mimicking the size of collagen fibrils in human AC. The polymer scaffolds were stabilized in physiological conditions and their stiffness was tuned by introducing the biocompatible natural crosslinker genipin. We produced scaffolds that were crosslinked with 1.0% genipin to obtain values of stiffness that were in between the stiffness of the superficial zone human AC of 600 ± 150 kPa and deep zone AC of 1854 ± 483 kPa, whereas the stiffness of 1.5% genipin crosslinked scaffold was similar to the stiffness of deep zone AC. The scaffolds were degradable, which was indicated by changes in the fibril structure and a decrease in the scaffold stiffness after seven months. Histological and immunohistochemical analysis after three weeks of culture with human articular chondrocytes (HACs) showed a cell viability of over 90% on the scaffolds and new extracellular matrix deposited on the scaffolds.

ASSESSMENT OF THREE-DIMENSIONAL ARCHITECTURE OF COLLAGEN FIBERS IN THE SUPERFICIAL ZONE OF BOVINE ARTICULAR CARTILAGE

2004 ◽  
Vol 08 (04) ◽  
pp. 167-179 ◽  
Author(s):  
J. P. Wu ◽  
T. B. Kirk ◽  
M. H. Zheng
Keyword(s):  
Articular Cartilage ◽  
Laser Scanning ◽  
3D Visualization ◽  
Articular Surface ◽  
3D Structure ◽  
Collagen Matrix ◽  
Laser Scanning Confocal Microscopy ◽  
Collagen Fibres ◽  
Superficial Zone ◽  
Bovine Articular Cartilage

The aim of this study is to investigate the structure and the collagen matrix of the superficial zone of articular cartilage using a 3D imaging technique. The split line thought to represent the orientation of the collagen fibres in the superficial zone was found using Hultkrantz's method. A semitransparent membrane was physically peeled off from the most superficial surface of bovine articular cartilage. Using fibre optic laser scanning confocal microscopy, the collagen matrix in normal cartilage, the membrane and the cartilage with the membrane peeled off were studied. The superficial zone was found to contain a more sophisticated 3D collagenous matrix than previously reported. The collagen matrix in the membrane consists of interwoven long collagen bundles, and the collagen fibres immediately subjacent to it align spatially in a predominantly oblique direction to the articular surface. The split line does not represent the orientation of the collagen in the membrane. This study presents a 3D visualization technique for a minimal-invasive examination of the 3D architecture of the collagen fibres in the superficial zone of articular cartilage, and offers a new insight into the 3D structure of the collagen matrix in the superficial zone of native cartilage.

scholarly journals An immunoelectron microscope study of the organization of proteoglycan monomer, link protein, and collagen in the matrix of articular cartilage.

1982 ◽  
Vol 93 (3) ◽  
pp. 921-937 ◽  
Author(s):  
A R Poole ◽  
I Pidoux ◽  
A Reiner ◽  
L Rosenberg
Keyword(s):  
Electron Microscopy ◽  
Hyaluronic Acid ◽  
Articular Cartilage ◽  
Guanidine Hydrochloride ◽  
Collagen Fibrils ◽  
Ultrastructural Organization ◽  
Deep Zone ◽  
Superficial Zone ◽  
Bovine Articular Cartilage ◽  
Link Protein

Monospecific antibodies to bovine cartilage proteoglycan monomer (PG) and link protein (LP) have been used with immunoperoxidase electron microscopy to study the distribution and organization of these molecules in bovine articular cartilage. The following observations were made: (a) The interterritorial matrix of the deep zone contained discrete interfibrillar particulate staining for PG and LP. This particulate staining, which was linked by faint bands of staining (for PG) or filaments (for LP), was spaced at 75- to 80-nm intervals. On collagen fibrils PG was also detected as particulate staining spaced at regular intervals (72 nm), corresponding to the periodicity of collagen cross-banding. The interfibrillar PG staining was often linked to the fibrillar PG staining by the same bands or filaments. The latter were cleaved by a proteinase-free Streptomyces hyaluronidase with the removal of much of the interfibrillar lattice. Since this enzyme has a specificity for hyaluronic acid, the observations indicate that the lattice contains a backbone of hyaluronic acid (which appeared as banded or filamentous staining) to which is attached LP and PG, the latter collapsing when the tissue is fixed, reacted with antibodies, and prepared for electron microscopy. Thishyaluronic acid is anchored to collagen fibrils at regular intervals where PG is detected on collagen. PG and LP detected by antibody in the interterritorial zones are essentially fully extractible with 4 M guanidine hydrochloride. These observations indicated that interfibrillar PG and LP is aggregated with HA in this zone. (b) The remainder of the cartilage matrix had a completely different organization of PG and LP. There was no evidence of a similar latticework based on hyaluronic acid. Instead, smaller more closely packed particulate staining for PG was seen everywhere irregularly distributed over and close to collagen fibrils. LP was almost undetectable in the territorial matrix of the deep zone, as observed previously. In the middle and superficial zones, stronger semiparticulate staining for LP was distributed over collagen fibrils. (c) In the superficial zone, reaction product for PG was distributed evenly on collagen fibrils as diffuse staining and also irregularly as particulate staining. LP was observed as semiparticulate staining over collagen fibrils. The diffuse staining for PG remained after extraction with 4 M guanidine hydrochloride. (d) In pericellular matrix, most clearly identified in middle and deep zones, the nature and organization of reaction product for PG and LP were similar to those observed in the territorial matrix, except that LP and PG were more strongly stained and amorphous staining for both components was also observed. (e) This study demonstrates striking regional variations of ultrastructural organization of PG and LP in articular cartilage...

scholarly journals The Mechanical Consequence of Removing the Superficial Zone of Articular Cartilage

2011 ◽  
Author(s):  
S. M. Hosseini ◽  
Y. Wu ◽  
C. C. van Donkelaar ◽  
K. Ito
Keyword(s):  
Articular Cartilage ◽  
Articular Surface ◽  
Dry Weight ◽  
Collagen Fibers ◽  
Matrix Composition ◽  
Middle Zone ◽  
Deep Zone ◽  
Superficial Zone ◽  
Diarthrodial Joints ◽  
Fluid Fraction

Articular cartilage (AC) functions as a load-bearing, low friction, and wear resistant material in diarthrodial joints. The distribution of AC matrix composition is highly depth-dependent. The fluid fraction in AC is 80% and decreases from surface to the depth of the tissue [1]. Collagen constitutes 70% of the tissue dry weight, and is highest in the superficial and deep zones and lowest in the middle zone [2]. Proteoglycans (PG’s) constitute 20–30% of the tissue dry weight. PG’s are lowest in the superficial zone, and highest in the middle zone. Although the PG content is lower in the deep zone than in the middle zone, the fixed charge density (FCD) is highest in the deep zone [3]. Apart from AC composition, its structure is also depth-dependent. In the superficial zone collagen fibers are densely packed, and are arranged parallel to the articular surface. In the middle zone collagen fibers are more randomly arranged. In the deep zone, the collagen fibers have their largest diameters and are arranged perpendicular to the subchondral bone (Fig. 1) [4].

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