scholarly journals Modelling cartilage mechanobiology

2003 ◽  
Vol 358 (1437) ◽  
pp. 1461-1471 ◽  
Author(s):  
Dennis R. Carter ◽  
Marcy Wong
Keyword(s):  
Articular Cartilage ◽  
Single Phase ◽  
Skeletal Development ◽  
Fluid Pressure ◽  
Superficial Layer ◽  
Tissue Mechanics ◽  
Joint Mechanics ◽  
Cartilage Growth ◽  
Skeletal Morphology

The growth, maintenance and ossification of cartilage are fundamental to skeletal development and are regulated throughout life by the mechanical cues that are imposed by physical activities. Finite element computer analyses have been used to study the role of local tissue mechanics on endochondral ossification patterns, skeletal morphology and articular cartilage thickness distributions. Using single–phase continuum material representations of cartilage, the results have indicated that local intermittent hydrostatic pressure promotes cartilage maintenance. Cyclic tensile strains (or shear), however, promote cartilage growth and ossification. Because single–phase material models cannot capture fluid exudation in articular cartilage, poroelastic (or biphasic) solid/fluid models are often implemented to study joint mechanics. In the middle and deep layers of articular cartilage where poroelastic analyses predict little fluid exudation, the cartilage phenotype is maintained by cyclic fluid pressure (consistent with the single–phase theory). In superficial articular layers the chondrocytes are exposed to tangential tensile strain in addition to the high fluid pressure. Furthermore, there is fluid exudation and matrix consolidation, leading to cell ‘flattening’. As a result, the superficial layer assumes an altered, more fibrous phenotype. These computer model predictions of cartilage mechanobiology are consistent with results of in vitro cell and tissue and molecular biology experiments.

Differential Regulation of Articular Cartilage Biomechanical and Biochemical Properties by IGF-1 and TGF-β1 During In Vitro Growth

2009 ◽  
Author(s):  
Michael E. Stender ◽  
Christian R. Flores ◽  
Kristin J. Dills ◽  
Gregory M. Williams ◽  
Kevin M. Stewart ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Growth Models ◽  
Biochemical Properties ◽  
Low Friction ◽  
Cartilage Growth ◽  
Detailed Characterization ◽  
Naturally Occurring ◽  
Tgf Β1

Articular cartilage (AC) is a load bearing material that provides a low friction wear resistant interface in synovial joints. Naturally-occurring and stimulated intrinsic repair of damaged AC is ineffective. Thus, there is a desire to engineer effective replacement tissue that could be used for AC repair. Previous studies [1] have shown that culture of immature cartilage with medium including TGF-β1 will result in a more mature tissue than culture with IGF-1. Detailed characterization of tissue mechanical properties would be helpful for development of cartilage growth models [2].

An In-Vitro Investigation of Sliding Friction Between Biomaterials for Cartilage Substitution and Articular Cartilage

2005 ◽  
Author(s):  
E. Northwood ◽  
R. Kowalski ◽  
J. Fisher
Keyword(s):  
Articular Cartilage ◽  
Single Phase ◽  
Sliding Friction ◽  
Frictional Coefficient ◽  
Polymeric Materials ◽  
Fluid Phase ◽  
Load Carriage ◽  
Simple Geometry ◽  
In Vitro Investigation

Understanding friction and wear of biomaterials when in contact with articular cartilage is vital within the development of future hemi-arthroplasty and cartilage substitution. This study aimed to compare the frictional properties of single phase and biphasic polymeric materials against articular cartilage. Continuous sliding friction was applied by means of a simple geometry wear simulator. The single-phase polymers produced peak frictional values of 0.37(±0.02). The biphasic hydrogel produced a peak frictional coefficient of 0.17(±0.05). It is postulated that this reduction in friction can be attributed to its biphasic properties, which instigates the fluid phase load carriage within the articular cartilage/hydrogel interface to be maintained for longer, reducing the frictional coefficient. This study illustrates the importance of biphasic properties within the tribology of future cartilage substitution materials.

scholarly journals Simulating the Growth of Articular Cartilage Explants in a Permeation Bioreactor to Aid in Experimental Protocol Design

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Timothy P. Ficklin ◽  
Andrew Davol ◽  
Stephen M. Klisch
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Articular Cartilage ◽  
Element Model ◽  
Cartilage Explants ◽  
Solid Matrix ◽  
Cartilage Growth ◽  
Growth Laws ◽  
Competing Hypotheses

Recently a cartilage growth finite element model (CGFEM) was developed to solve nonhomogeneous and time-dependent growth boundary-value problems (Davol et al., 2008, “A Nonlinear Finite Element Model of Cartilage Growth,” Biomech. Model. Mechanobiol., 7, pp. 295–307). The CGFEM allows distinct stress constitutive equations and growth laws for the major components of the solid matrix, collagens and proteoglycans. The objective of the current work was to simulate in vitro growth of articular cartilage explants in a steady-state permeation bioreactor in order to obtain results that aid experimental design. The steady-state permeation protocol induces different types of mechanical stimuli. When the specimen is initially homogeneous, it directly induces homogeneous permeation velocities and indirectly induces nonhomogeneous solid matrix shear stresses; consequently, the steady-state permeation protocol is a good candidate for exploring two competing hypotheses for the growth laws. The analysis protocols were implemented through the alternating interaction of the two CGFEM components: poroelastic finite element analysis (FEA) using ABAQUS and a finite element growth routine using MATLAB. The CGFEM simulated 12 days of growth for immature bovine articular cartilage explants subjected to two competing hypotheses for the growth laws: one that is triggered by permeation velocity and the other by maximum shear stress. The results provide predictions for geometric, biomechanical, and biochemical parameters of grown tissue specimens that may be experimentally measured and, consequently, suggest key biomechanical measures to analyze as pilot experiments are performed. The combined approach of CGFEM analysis and pilot experiments may lead to the refinement of actual experimental protocols and a better understanding of in vitro growth of articular cartilage.

scholarly journals Self-organized emergence of hyaline cartilage in hiPSC-derived multi-tissue organoids

2021 ◽  
Author(s):  
Manci Li ◽  
Juan E. Abrahante ◽  
Amanda Vegoe ◽  
Yi Wen Chai ◽  
Beth Lindborg ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Lower Limb ◽  
Regulatory Networks ◽  
Hyaline Cartilage ◽  
Therapeutic Potential ◽  
Cartilage Growth ◽  
Cartilage Development ◽  
Self Organized

Despite holding great therapeutic potential, existing protocols for in vitro chondrogenesis and hyaline cartilage production from human induced pluripotent stem cells (hiPSC) are laborious and complex with unclear long-term consequences. Here, we developed a simple xeno- and feeder-free protocol for human hyaline cartilage production in vitro using hydrogel-cultured multi-tissue organoids (MTOs). We investigate gene regulatory networks during spontaneous hiPSC-MTO differentiation using RNA sequencing and bioinformatic analyses. We find the interplays between BMPs and neural FGF pathways are associated with the phenotype transition of MTOs. We recognize TGF-beta/BMP and Wnt signaling likely contribute to the long-term maintenance of MTO cartilage growth and further adoption of articular cartilage development. By comparing the MTO transcriptome with human lower limb chondrocytes, we observe that the expression of chondrocyte-specific genes in MTO shows a strong correlation with fetal lower limb chondrocytes. Collectively, our findings describe the self-organized emergence of hyaline cartilage in MTO, its associated molecular pathways, and its spontaneous adoption of articular cartilage development trajectory.

scholarly journals The Scaffold–Articular Cartilage Interface: A Combined In Vitro and In Silico Analysis Under Controlled Loading Conditions

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Tony Chen ◽  
Moira M. McCarthy ◽  
Hongqiang Guo ◽  
Russell Warren ◽  
Suzanne A. Maher
Keyword(s):  
Articular Cartilage ◽  
Mechanical Loading ◽  
In Silico ◽  
Fluid Pressure ◽  
In Silico Analysis ◽  
Element Model ◽  
Loading Conditions ◽  
Optimal Method ◽  
Biphasic Finite Element

The optimal method to integrate scaffolds with articular cartilage has not yet been identified, in part because of our lack of understanding about the mechanobiological conditions at the interface. Our objective was to quantify the effect of mechanical loading on integration between a scaffold and articular cartilage. We hypothesized that increased number of loading cycles would have a detrimental effect on interface integrity. The following models were developed: (i) an in vitro scaffold–cartilage explant system in which compressive sinusoidal loading cycles were applied for 14 days at 1 Hz, 5 days per week, for either 900, 1800, 3600, or 7200 cycles per day and (ii) an in silico inhomogeneous, biphasic finite element model (bFEM) of the scaffold–cartilage construct that was used to characterize interface micromotion, stress, and fluid flow under the prescribed loading conditions. In accordance with our hypothesis, mechanical loading significantly decreased scaffold–cartilage interface strength compared to unloaded controls regardless of the number of loading cycles. The decrease in interfacial strength can be attributed to abrupt changes in vertical displacement, fluid pressure, and compressive stresses along the interface, which reach steady-state after only 150 cycles of loading. The interfacial mechanical conditions are further complicated by the mismatch between the homogeneous properties of the scaffold and the depth-dependent properties of the articular cartilage. Finally, we suggest that mechanical conditions at the interface can be more readily modulated by increasing pre-incubation time before the load is applied, as opposed to varying the number of loading cycles.

A Numerical Model of Mechanics of Osteoarthritis in Human Knee Joint

2012 ◽  
Author(s):  
Yaghoub Dabiri ◽  
LePing Li
Keyword(s):  
Articular Cartilage ◽  
Knee Joint ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Solid Matrix ◽  
Joint Mechanics ◽  
Human Knee ◽  
Human Knee Joint ◽  
Contact Loads ◽  
Model Fluid

Articular cartilage is composed of water entrapped in a solid matrix formed by proteoglycans and collagen fibers. Therefore, the mechanical behavior of this tissue is determined by all of these three components. In addition, the properties of articular cartilage vary along the depth and by location. In the human knee joint, the three dimensional geometry as well as the contact between the cartilaginous tissues plays essential roles in the joint mechanics. On the other hand, initiation and progression of osteoarthritis (OA) could be partly caused by contact loads. Consequently, the fibrillar and non-fibrillar matrices, the three dimensional geometry and the contact between the tissues should be considered as essential parameters in the study of the mechanics of osteoarthritis. However, previous studies on OA mechanics were mostly limited to explants geometries [1]. Also, the contact mechanics associated with the fluid pressure have not been considered in the previous OA models. In a recent knee model, fluid was considered in femoral cartilage but not in the menisci [2]. Additionally, the depth-dependent mechanical properties were not included in that model.

Effects of in vitro low oxygen tension preconditioning of buccal fat pad stem cells on in Vivo articular cartilage tissue repair

Life Sciences ◽  
2021 ◽  
pp. 119728
Author(s):  
Fatemeh Dehghani Nazhvani ◽  
Leila Mohammadi Amirabad ◽  
Arezo Azari ◽  
Hamid Namazi ◽  
Simzar Hosseinzadeh ◽  
...  
Keyword(s):  
Stem Cells ◽  
Articular Cartilage ◽  
Tissue Repair ◽  
Cartilage Tissue ◽  
Low Oxygen ◽  
Fat Pad ◽  
Buccal Fat Pad ◽  
Low Oxygen Tension

Normal and degenerating articular cartilage: In vitro correlation of MR imaging and histologic findings

1992 ◽  
Vol 2 (1) ◽  
pp. 41-46 ◽  
Author(s):  
Nancy L. Monson ◽  
Victor M. Haughton ◽  
Jean M. Modi ◽  
Lowell A. Sether ◽  
Khang-Cheng Ho PhD
Keyword(s):  
Articular Cartilage ◽  
Mr Imaging
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