Alterations in the Mechanical Properties of the Human Chondrocyte Pericellular Matrix With Osteoarthritis

2003 ◽  
Vol 125 (3) ◽  
pp. 323-333 ◽  
Author(s):  
Leonidas G. Alexopoulos ◽  
Mansoor A. Haider ◽  
Thomas P. Vail ◽  
Farshid Guilak
Keyword(s):  
Articular Cartilage ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Theoretical Models ◽  
Significant Loss ◽  
Surface Zone ◽  
Human Articular Cartilage ◽  
Pericellular Matrix ◽  
Osteoarthritic Cartilage ◽  
Isolation Technique

In articular cartilage, chondrocytes are surrounded by a pericellular matrix (PCM), which together with the chondrocyte have been termed the “chondron.” While the precise function of the PCM is not known there has been considerable speculation that it plays a role in regulating the biomechanical environment of the chondrocyte. In this study, we measured the Young’s modulus of the PCM from normal and osteoarthritic cartilage using the micropipette aspiration technique, coupled with a newly developed axisymmetric elastic layered half-space model of the experimental configuration. Viable, intact chondrons were extracted from human articular cartilage using a new microaspiration-based isolation technique. In normal cartilage, the Young’s modulus of the PCM was similar in chondrons isolated from the surface zone (68.9±18.9 kPa) as compared to the middle and deep layers (62.0±30.5 kPa). However, the mean Young’s modulus of the PCM (pooled for the two zones) was significantly decreased in osteoarthritic cartilage (66.5±23.3 kPa versus 41.3±21.1 kPa, p<0.001). In combination with previous theoretical models of cell-matrix interactions in cartilage, these findings suggest that the PCM has an important influence on the stress-strain environment of the chondrocyte that potentially varies with depth from the cartilage surface. Furthermore, the significant loss of PCM stiffness that was observed in osteoarthritic cartilage may affect the magnitude and distribution of biomechanical signals perceived by the chondrocytes.

scholarly journals AFM-Based Method for Measurement of Normal and Osteoarthritic Human Articular Cartilage Surface Roughness

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2302 ◽  
Author(s):  
Mikhail Ihnatouski ◽  
Jolanta Pauk ◽  
Dmitrij Karev ◽  
Boris Karev
Keyword(s):  
Atomic Force Microscopy ◽  
Articular Cartilage ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Human Articular Cartilage ◽  
Roughness Parameters ◽  
Arithmetic Average ◽  
Force Microscopy ◽  
Atomic Force ◽  
Healthy Cartilage

In osteoarthrosis, pathological features of articular cartilage are associated with degeneration and nanomechanical changes. The aim of this paper is to show that indentation-atomic force microscopy can monitor wear-related biomechanical changes in the hip joint of patients with osteoarthritis. Fifty patients (N = 50), aged 40 to 65, were included in the study. The mechanical properties and the submicron surface morphology of hyaline cartilage were investigated using atomic force microscopy. Measurements of the roughness parameters of cartilage surfaces were performed, including the arithmetic average of absolute values (Ra), the maximum peak height (Rp), and the mean spacing between local peaks (S). The arithmetic mean of the absolute values of the height of healthy cartilage was 86 nm, while wear began at Ra = 73 nm. The maximum changes of values of the roughness parameters differed from the healthy ones by 71%, 80%, and 51% for Ra, Rp, and S, respectively. Young’s modulus for healthy cartilage surfaces ranged from 1.7 to 0.5 MPa. For the three stages of cartilage wear, Young’s modulus increased, and then it approached the maximum value and decreased. AFM seems to be a powerful tool for surface analysis of biological samples as it enables indentation measurements in addition to imaging.

scholarly journals Comparison of Compressive Stress-Relaxation Behavior in Osteoarthritic (ICRS Graded) Human Articular Cartilage

2017 ◽  
Author(s):  
Rajesh Kumar ◽  
David M. Pierce ◽  
Vidar Isaksen ◽  
Catharina de Lange Davies ◽  
Jon O. Drogset ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Stress Relaxation ◽  
Computational Models ◽  
Articular Surface ◽  
Significant Loss ◽  
Relaxation Behavior ◽  
Human Articular Cartilage ◽  
Osteoarthritic Cartilage ◽  
Human Cartilage ◽  
Stress Relaxation Behavior

Osteoarthritis (OA) is a common joint disorder found mostly in elderly people. The role of mechanical behavior in the progression of OA is complex and remains unclear. The stress-relaxation behavior of human articular cartilage in clinically defined osteoarthritic stages may have importance in diagnosis and prognosis of OA. In this study we investigated differences in the biomechanical responses among human cartilage of ICRS grades I, II and III using polymer dynamics theory. We collected 24 explants of human articular cartilage (eight each of ICRS grade I, II and III) and acquired stress-relaxation data applying a continuous load on the articular surface of each cartilage explant for 1180 s. We observed a significant decrease in Young&rsquo;s modulus, stress-relaxation time, and stretching exponent in advanced stages of OA (ICRS grade III). The stretch exponential model indicated that significant loss in hyaluronic acid polymer might be the reason for the loss of proteoglycan in advanced OA. This work encourages further biomechanical modelling of osteoarthritic cartilage utilizing these data as input parameters to enhance the fidelity of computational models aimed at revealing how mechanical behaviors play a role in pathogenesis of OA.

scholarly journals Immunolocalization of type III collagen in human articular cartilage prepared by high-pressure cryofixation, freeze-substitution, and low-temperature embedding.

1995 ◽  
Vol 43 (4) ◽  
pp. 421-427 ◽  
Author(s):  
R D Young ◽  
P A Lawrence ◽  
V C Duance ◽  
T Aigner ◽  
P Monaghan
Keyword(s):  
High Pressure ◽  
Articular Cartilage ◽  
Polyclonal Antibodies ◽  
Freeze Substitution ◽  
Immunogold Electron Microscopy ◽  
Type Iii Collagen ◽  
Human Articular Cartilage ◽  
Chemical Fixation ◽  
Osteoarthritic Cartilage ◽  
Type Iii

We localized Type III collagen by immunogold electron microscopy in resin sections of intact normal and osteoarthritic human articular cartilage. Comparisons of antibody staining between tissue prepared by high-pressure cryofixation and freeze-substitution without fixatives and that exposed to conventional mild chemical fixation with paraformaldehyde showed that dedicated cryotechniques yielded superior preservation of epitopes that are modified by chemical fixation, and simultaneously provided good ultrastructural preservation. Type III collagen was detected with two polyclonal antibodies, one against the triple-helical domain of the molecule and a second against the more antigenic, globular amino pro-peptide domain, which in this collagen is retained in the extracellular matrix after secretion. Positive labeling was seen in association with the major interstitial fibrils, suggesting co-polymerization of Types III and II collagen in cartilage. Type III collagen could not be detected in aldehyde-fixed normal cartilage. In fixed osteoarthritic cartilage, Type III was detectable only when the antibody to the amino pro-peptide was employed. In contrast, high-pressure cryofixation and freeze-substitution preserved epitopes for both antibodies, permitting immunodetection of Type III collagen in normal and osteoarthritic cartilage. Cryotechniques offer exciting possibilities for significantly improving the immunolocalization of collagens and other fixative-sensitive antigens in situ.

scholarly journals Experimental Investigation of Stress Distributions in 3D Printed Graded Plates with a Circular Hole

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7845
Author(s):  
Quanquan Yang ◽  
He Cao ◽  
Youcheng Tang ◽  
Yun Li ◽  
Xiaogang Chen
Keyword(s):  
Experimental Investigation ◽  
Stress Concentration ◽  
Young’S Modulus ◽  
Circular Hole ◽  
Young's Modulus ◽  
Theoretical Models ◽  
Research Field ◽  
Functionally Graded ◽  
Stress Distributions ◽  
Functionally Graded Plates

An experimental investigation is presented for the stress distributions in functionally graded plates containing a circular hole. On the basis of the authors’ previously constructed theoretical model, two kinds of graded plates made of discrete rings with increasing or decreasing Young’s modulus were designed and fabricated in virtue of multi-material 3D printing. The printed graded plates had accurate size, smooth surface, and good interface. The strains of two graded plates under uniaxial tension were measured experimentally using strain gages. The stresses were calculated within the range of linear elastic from the measured strains and compared with analytical theory. It is found that the experimental results are consistent with the theoretical results, and both of them indicate that the stress concentration around the hole reduces obviously in graded plates with radially increasing Young’s modulus, in comparison with that of perforated homogenous plates. The successful experiment in the paper provides a good basis and support for the establishment of theoretical models and promotes the in-depth development of the research field of stress concentration in functionally graded plates.

Determination of Poisson’s Ratio of Articular Cartilage by Indentation Using Different-Sized Indenters

2004 ◽  
Vol 126 (2) ◽  
pp. 138-145 ◽  
Author(s):  
Hui Jin ◽  
Jack L. Lewis
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Nonlinear Equation ◽  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Indentation Test ◽  
Test Method ◽  
Poisson's Ratio ◽  
Unconfined Compression

Articular cartilage is often characterized as an isotropic elastic material with no interstitial fluid flow during instantaneous and equilibrium conditions, and indentation testing commonly used to deduce material properties of Young’s modulus and Poisson’s ratio. Since only one elastic parameter can be deduced from a single indentation test, some other test method is often used to allow separate measurement of both parameters. In this study, a new method is introduced by which the two material parameters can be obtained using indentation tests alone, without requiring a secondary different type of test. This feature makes the method more suitable for testing small samples in situ. The method takes advantages of the finite layer effect. By indenting the sample twice with different-sized indenters, a nonlinear equation with the Poisson’s ratio as the only unknown can be formed and Poisson’s ratio obtained by solving the nonlinear equation. The method was validated by comparing the predicted Poisson’s ratio for urethane rubber with the manufacturer’s supplied value, and comparing the predicted Young’s modulus for urethane rubber and an elastic foam material with modulii measured by unconfined compression. Anisotropic and nonhomogeneous finite-element (FE) models of the indentation were developed to aid in data interpretation. Applying the method to bovine patellar cartilage, the tissue’s Young’s modulus was found to be 1.79±0.59MPa in instantaneous response and 0.45±0.26MPa in equilibrium, and the Poisson’s ratio 0.503±0.028 and 0.463±0.073 in instantaneous and equilibrium, respectively. The equilibrium Poisson’s ratio obtained in our work was substantially higher than those derived from biphasic indentation theory and those optically measured in an unconfined compression test. The finite element model results and examination of viscoelastic-biphasic models suggest this could be due to viscoelastic, inhomogeneity, and anisotropy effects.

scholarly journals Ultrastructure of Chondrocytes in Osteoarthritic Femoral Articular Cartilage

2015 ◽  
Vol 11 (3) ◽  
pp. 221-225
Author(s):  
Nj Goya ◽  
M Gupta ◽  
K Joshi
Keyword(s):  
Electron Microscope ◽  
Articular Cartilage ◽  
Control Group ◽  
Human Articular Cartilage ◽  
Joint Motion ◽  
Age Group ◽  
Radiographic Evidence ◽  
Osteoarthritic Cartilage ◽  
Total Knee ◽  
Ultrastructural Findings

Background Osteoarthritis (OA) is a common problem in elderly, but it is not an inevitable feature of ageing. About 80-90% of individuals of both sexes have radiographic evidence of OA by the time they reach an age of 65. But not all of them have the symptoms like pain and decreased joint motion. Objective The objective of the present study was conducted to find out whether the osteoarthritic changes in human articular cartilage are similar to the ageing process or not. Methods Femoral articular cartilage specimens obtained from 13 osteoarthritic patients (52-80years) undergoing total knee replacement and 9 cadavers of same age group (50-80years) (control) were processed and studied under electron microscope. The ultrastructure of the cartilage from the two groups was compared with each other. Results Under the electron microscope, articular cartilage from control group had chondrocytes having a secretary cell characteristic with prominent nucleus and well developed organelles. In osteoarthritic cartilage, degenerating or necrotic chondrocytes were found. Nuclei of these chondrocytes appeared lobulated or indented. Chondrocytes below the fibrillated surface had dilated and irregular endoplasmic reticulum. Electron dense lipid deposits in the extracelluar matrix as well as intracytoplasmic glycogen deposits were much increased in osteoarthritic cartilage as compared to the control group. Amount of perinuclear intracytoplasmic fine filaments was also increased in the chondrocytes of osteoarthritic cartilage. Conclusion Ultrastructural findings of the osteoarthritic articular cartilage were much different from the ageing non-osteoarthritic cartilage. Hence, OA should be considered a specific process and not simply an inevitable feature of ageing. DOI: http://dx.doi.org/10.3126/kumj.v11i3.12507 Kathmandu Univ Med J 2013; 43(3):221-225

Elastic Strain Energy of a Nanowire in Three-Point Bending Test with the Consideration of Surface Effects

2011 ◽  
Vol 268-270 ◽  
pp. 67-71
Author(s):  
Xian Wei Zeng ◽  
Jia Quan Deng
Keyword(s):  
Young’S Modulus ◽  
Elastic Strain ◽  
Strain Energy ◽  
Young's Modulus ◽  
Elastic Strain Energy ◽  
Theoretical Models ◽  
Bending Test ◽  
Three Point Bending ◽  
Force Microscopy ◽  
Atomic Force

Three-point bending tests of nanowires with Contact atomic force microscopy reveal that the Young’s modulus of a nanowire is size-dependent. The modulus changes with the diameter of a nanowire. This size dependency can be explained within the framework of classical continuum mechanics by including the effects of surface stress. In this study, an analytical solution has been derived for the elastic strain energy of a nanowire with both ends clamped and contacted by an AFM tip at its midpoint. Different from previous theoretical models, the present model can handle the case of large deflection, where the displacement of the nanowire is in the same order of the diameter. Based on the equivalence of elastic strain energy, the apparent Young’s modulus of a nanowire is expressed as a function of the elastic modulus of the bulk and that of the surface, and the dimensions of a nanowire.

scholarly journals Immunohistochemical localization of fibronectin and chondronectin in canine articular cartilage.

1988 ◽  
Vol 36 (6) ◽  
pp. 581-588 ◽  
Author(s):  
N Burton-Wurster ◽  
V J Horn ◽  
G Lust
Keyword(s):  
Articular Cartilage ◽  
External Medium ◽  
Articular Surface ◽  
Immunohistochemical Localization ◽  
Pericellular Matrix ◽  
Osteoarthritic Cartilage ◽  
Matrix Interactions ◽  
The Matrix ◽  
Cut Surface ◽  
Disease Free

We compared the distribution of fibronectin and chondronectin within the matrix of canine articular cartilage. Fibronectin was found throughout the matrix as well as pericellularly. In contrast, chondronectin was observed predominantly associated with the cell or pericellular matrix. Interactions of these molecules with matrix components in the pericellular matrix probably differs, however, since concentrations of hyaluronidase which prevented detection of pericellular fibronectin allowed detection of chondronectin. Chondronectin and fibronectin were detected in osteoarthritic cartilage as well as in disease-free cartilage. Penetration of biotinylated fibronectin into cartilage from the external medium occurred only in osteoarthritic cartilage and proceeded only from the articular surface. Disease-free cartilage appeared to maintain a barrier to fibronectin penetration from the articular surface which was sustained even after the proteoglycan content was markedly depleted by incubation of cartilage with catabolin or lipopolysaccharide. In cartilage that was proteoglycan-depleted, the only detectable penetration of external fibronectin was from the cut surface.

The Inhomogeneous Mechanical Properties of the Pericellular Matrix of Articular Cartilage Measured In Situ by Atomic Force Microscopy

2009 ◽  
Author(s):  
Rebecca E. Wilusz ◽  
Eric M. Darling ◽  
Michael P. Bolognesi ◽  
Stefan Zauscher ◽  
Farshid Guilak
Keyword(s):  
Mechanical Properties ◽  
Atomic Force Microscopy ◽  
Articular Cartilage ◽  
Biomechanical Properties ◽  
Human Articular Cartilage ◽  
Pericellular Matrix ◽  
Force Microscopy ◽  
Narrow Region ◽  
Atomic Force

Articular cartilage is the connective tissue that lines the articulating surfaces of diarthrodial joints, providing a low-friction, load-bearing surface during joint motion. Articular cartilage comprises of a single cell type, the chondrocyte, embedded within an extensive extracellular matrix (ECM). Each chondrocyte is surrounded by a narrow region called the pericellular matrix (PCM) that is distinct from the ECM in both its biochemical composition [1] and biomechanical properties [2]. While multiple techniques have been used to measure the mechanical properties of the PCM, including micropipette aspiration of isolated chondrons [2], these studies required mechanical or enzymatic extraction of the chondrocyte and surrounding PCM (i.e., the “chondron” [1]) from the cartilage, and the influence of this isolation process on PCM properties is unknown. Atomic force microscopy (AFM) provides a high resolution form of nano- and microindentation approaches that can be used to measure local mechanical properties in situ [3,4]. The objective of this study was to use AFM to quantify the biomechanical properties of the ECM and PCM of human articular cartilage in situ.

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