Biorheology - Volume 43, issue 3-4

Authors: Yang, Jing-Wei | Isla, Natalia de | Huselstein, Céline | Sarda-Kolopp, Marie-Nathalie | Li, Na | Li, Yin-Ping | Jing-Ping, Ou-Yang | Stoltz, Jean-François | Eljaafari, Assia

Article Type: Research Article

Abstract: Mesenchymal stem cells (MSCs) have the potential to differentiate into distinct mesenchymal tissue cells. They are easy to expand while maintaining their undifferentiated state, which suggests that these cells could be an attractive cell source for tissue engineering of cartilage. In vitro high density micromass culture has been widely used for chondrogenesis induction. Our objective was to investigate human MSCs cell cycle, viability and differentiation in these conditions. Therefore, to induce human MSCs chondrogenesis, micromasses were cultured in the presence of transforming growth factor-β1 in serum free medium for 21 days. Cell cycle, cell viability and cell phenotype were analyzed …by flow cytometry. From day 0 to 7, the G0/G1 phase increased, whereas the S phase decreased gradually, but cell cycle phases (S, G0/G1 and G2/M) did not significantly change after day 7. Less than 10% of cells were apoptotic, but no necrosis was observed, even at day 21. We observed a decrease in CD90 and CD105 expression, from day 0 to 21. In conclusion, our results demonstrate a good viability of human MSCs in micromass culture during the whole period of culture. Moreover, micromass culture allowed human MSCs to be synchronized at the G0/G1 phase, while their phenotype suggested some degree of differentiation. Show more

Keywords: Mesenchymal stem cell, TGF-β1, viability, cell cycle, differentiation

Citation: Biorheology, vol. 43, no. 3-4, pp. 489-496, 2006

Authors: Ng, Kenneth W. | Mauck, Robert L. | Statman, Lauren Y. | Lin, Evan Y. | Ateshian, Gerard A. | Hung, Clark T.

Article Type: Research Article

Abstract: The application of dynamic physiologic loading to a bilayered chondrocyte-seeded agarose construct with a 2% (wt/vol) top layer and 3% (wt/vol) bottom layer was hypothesized to (1) improve overall construct properties and (2) result in a tissue that mimics the mechanical inhomogeneity of native cartilage. Dynamic loading over the 28 day culture period was found to significantly increase bulk mechanical and biochemical properties versus free-swelling culture. The initial depth-distribution of the compressive Young's modulus (EY ) reflected the intrinsic properties of the gel in each layer and a similar trend to the native tissue, with a softer 2% gel layer …and a much stiffer 3% gel layer. After 28 days in culture, free-swelling conditions maintained this general trend while loaded constructs possessed a reverse profile, with significant increases in EY observed only in the 2% gel. Histological analysis revealed preferential matrix formation in the 2% agarose layer, with matrix localized more pericellularly in the 3% agarose layer. Finite element modeling revealed that, prior to significant matrix elaboration, the 2% layer experiences increased mechanical stimuli (fluid flow and compressive strain) during loading that may enhance chondrocyte stimulation and nutrient transport in that layer, consistent with experimental observations. From these results, we conclude that due to the limitations in 3% agarose, the use of this type of bilayered construct to construct depth-dependent inhomogeneity similar to the native tissue is not likely to be successful under long-term culture conditions. Our study underscores the importance of other physical properties of the scaffold that may have a greater influence on interconnected tissue formation than intrinsic scaffold stiffness. Show more

Keywords: Cartilage, tissue engineering, inhomogeneity, digital image correlation, agarose, scaffold design

Citation: Biorheology, vol. 43, no. 3-4, pp. 497-507, 2006

Authors: Jakab, Karoly | Damon, Brook | Neagu, Adrian | Kachurin, Anatolij | Forgacs, Gabor

Article Type: Research Article

Abstract: Bioprinting is an evolving tissue engineering technology. It utilizes computer controlled three-dimensional printers for rapid and high-precision construction of three-dimensional biological structures. We employed discrete and continuous bioprinting to build three-dimensional tissue constructs. In the former case bioink particles – spherical cell aggregates composed of many thousands of cells – are delivered one by one into biocompatible scaffolds, the biopaper. Structure formation takes place by the subsequent fusion of the bioink particles due to their liquid-like and self-assembly properties. In the latter case a mixture of cells and scaffold material is extruded from the biocartridge akin to toothpaste to arrive …at the desired construct. Specifically, we built rectangular tissue blocks of several hundred microns in thickness as well as tubular structures of several millimeters in height. The physical basis of structure formation was studied by computer simulations. Show more

Keywords: Tissue engineering, bioprinter, spherical cell aggregate, tissue liquidity, self-assembly

Citation: Biorheology, vol. 43, no. 3-4, pp. 509-513, 2006

Authors: Martin, J.A. | Buckwalter, J.A.

Article Type: Research Article

Abstract: Post-traumatic osteoarthritis is the form of osteoarthritis (OA) that develops following joint injury. Although its end-stage is indistinguishable from idiopathic OA, many patients with post-traumatic OA are younger than those with idiopathic OA, and they have a well-defined precipitating insult. Clinical and experimental studies suggest that excessive acute impact energy or chronic mechanical overload cause the degeneration of the articular surface responsible for post-traumatic OA. Yet, the mechanisms by which excessive mechanical force causes OA remain unknown. For these reasons it has not been possible to develop effective methods of preventing or decreasing the risk of post-traumatic OA. We hypothesized …that mechanical loading that exceeds the tolerance of the articular surface causes chondrocyte damage due to oxidative stress. Our in vitro tests of human articular cartilage samples showed that shear stress causes chondrocyte death and that anti-oxidants decrease the shear stress induced cell death. These observations suggest that specific patterns of loading are particularly damaging to articular surfaces and that improved treatments of joint injuries may include mechanical methods of minimizing shear stresses and biologic methods of minimizing oxidative damage. Show more

Keywords: Osteoarthritis, trauma, post-traumatic osteoarthritis, oxidative damage, chondrocytes, anti-oxidants

Citation: Biorheology, vol. 43, no. 3-4, pp. 517-521, 2006

Authors: Nieminen, Heikki J. | Töyräs, Juha | Laasanen, Mikko S. | Jurvelin, Jukka S.

Article Type: Research Article

Abstract: Mechano-acoustic and elastographic techniques may provide quantitative means for the in vivo diagnostics of articular cartilage. These techniques assume that sound speed does not change during tissue loading. As articular cartilage shows volumetric changes during compression, acoustic properties of cartilage may change affecting the validity of mechano-acoustic measurements. In this study, we examined the ultrasound propagation through human, bovine and porcine articular cartilage during stress-relaxation in unconfined compression. The time of flight (TOF) technique with known cartilage thickness (true sound speed) as well as in situ calibration method [Suh, Youn, Fu, J. Biomech. 34 (2001), 1347–1353] were used for the …determination of sound speed. Ultrasound speed and attenuation decreased in articular cartilage during ramp compression, but returned towards the level of original values during relaxation. Variations in ultrasound speed induced an error in strain and compressive moduli provided that constant ultrasound speed and time-of-flight data was used to determine the tissue thickness. Highest errors in strain (−11.8±12.0%) and dynamic modulus (15.4±17.9%) were recorded in bovine cartilage. TOF and in situ calibration methods yielded different results for changes in sound speed during compression. We speculate that the variations in acoustic properties in loaded cartilage are related to rearrangement of the interstitial matrix, especially to that of collagen fibers. In human cartilage the changes, are, however relatively small and, according to the numerical simulations, mechano-acoustic techniques that assume constant acoustic properties for the cartilage will not be significantly impaired by this phenomenon. Show more

Keywords: Articular cartilage, osteoarthrosis, mechanical indentation, ultrasound speed, ultrasound attenuation

Citation: Biorheology, vol. 43, no. 3-4, pp. 523-535, 2006

Authors: Adams, Michael A.

Article Type: Research Article

Abstract: There is a growing literature concerning chondrocyte responses to mechanical loading, but relatively little is known about the mechanical environment these cells experience in a living joint. Calculations indicate that high forces are applied to limb joints whenever the joints are flexed, because flexion can cause body weight to act on long lever arms compared to the joint centre, whereas the muscles which extend the joint act on much shorter lever arms. As a result, joint reaction forces (which compress the cartilage) can rise to 3–6 times body weight during activities such as stair climbing. Articular cartilage tends to spread …this load evenly over the joint surface, but is too thin to do this well, and compressive stresses can rise to 10–20 MPa. Within cartilage, matrix stresses vary locally, possibly as a result of variation in composition or undulations in the subchondral bone, and further modifications of stress occur within each chondron. Articular cartilage is a fibrous solid and cells within it are deformed by mechanical loading rather than subjected to a hydrostatic pressure. The mechanical environment of chondrocytes can best be reproduced in vitro by direct compression of the articular surface of cartilage which is supported naturally by adjacent cartilage and subchondral bone. Show more

Keywords: Cartilage, mechanics, mechanobiology, matrix, stress

Citation: Biorheology, vol. 43, no. 3-4, pp. 537-545, 2006

Authors: Goebel, Jean Christophe | Watrin-Pinzano, Astrid | Bettembourg-Brault, Isabelle | Odille, Freddy | Felblinger, Jacques | Chary-Valckenaere, Isabelle | Netter, Patrick | Blum, Alain | Gillet, Pierre | Loeuille, Damien

Article Type: Research Article

Abstract: Objectives: As the early form of OA is characterized by elevated water content in the cartilage tissue, the purpose of this study was to verify in vivo if age-related changes in patellar cartilage in healthy volunteers can be detected using quantitative MRI with T2 mapping and volume measurement MRI methods. Design: Thirty healthy volunteers of various classes of age (18 to 65 years old) were enrolled in this study. MR images of the patellar cartilage were acquired at 1.5T. Patellar cartilage volume and T2 maps were determined. Results: Despite non-significance, there was a trend in reducing cartilage volume with ageing …(r: −0.25). In contrast global T2 slightly increased with ageing (r: 0.46). BMI (r: 0.51) and bone volume (r: 0.69) are well correlated to cartilage volume. Conclusion. Age-related physiologic changes in the water content of patellar cartilage can be detected using MRI. The proposed T2-mapping method, coupled with other non-invasive MR cartilage imaging techniques, could aid in the early diagnosis of OA. Show more

Keywords: Cartilage, MRI, T2 map, volume, patella, age-related changes

Citation: Biorheology, vol. 43, no. 3-4, pp. 547-551, 2006

Authors: Marsano, A. | Wendt, D. | Quinn, T.M. | Sims, T.J. | Farhadi, J. | Jakob, M. | Heberer, M. | Martin, I.

Article Type: Research Article

Abstract: In this study, we aimed at validating a rotary cell culture system (RCCS) bioreactor with medium recirculation and external oxygenation, for cartilage tissue engineering. Primary bovine and human culture-expanded chondrocytes were seeded into non-woven meshes of esterified hyaluronan (HYAFF® -11), and the resulting constructs were cultured statically or in the RCCS, in the presence of insulin and TGFβ3, for up to 4 weeks. Culture in the RCCS did not induce significant differences in the contents of glycosaminoglycans (GAG) and collagen deposited, but markedly affected their distribution. In contrast to statically grown tissues, engineered cartilage cultured in the RCCS had a …bi-zonal structure, consisting of an outgrowing fibrous capsule deficient in GAG and rich in collagen, and an inner region more positively stained for GAG. Structurally, trends were similar using primary bovine or expanded human chondrocytes, although the human cells deposited inferior amounts of matrix. The use of the presented RCCS, in conjunction with the described medium composition, has the potential to generate bi-zonal tissues with features qualitatively resembling the native meniscus. Show more

Keywords: Tissue engineering, bioreactor, hydrodynamic flow, articular chondrocytes, rotating wall vessel, meniscus

Citation: Biorheology, vol. 43, no. 3-4, pp. 553-560, 2006

Authors: Moulin, David | Poleni, Paul-Emile | Kirchmeyer, Mélanie | Sebillaud, Sylvie | Koufany, Meriem | Netter, Patrick | Terlain, Bernard | Bianchi, Arnaud | Jouzeau, Jean-Yves

Article Type: Research Article

Abstract: In response to inflammatory cytokines, chondrocytes and synovial fibroblasts produce high amounts of prostaglandins (PG) which self-perpetuate locally the inflammatory reaction. Prostaglandins act primarily through membrane receptors coupled to G proteins but also bind to nuclear Peroxisome Proliferator-Activated Receptors (PPARs). Amongst fatty acids, the cyclopentenone metabolite of PGD2 , 15-deoxy-$\Delta\tsup{12,14}$ PGJ2 (15d-PGJ2 ), was shown to be a potent ligand of the PPARγ isotype prone to inhibit the production of inflammatory mediators. As the stimulated synthesis of PGE2 originates from the preferential coupling of inducible enzymes, cyclooxygenase-2 (COX-2) and membrane PGE synthase-1 (mPGES-1), we investigated the potency …of 15d-PGJ2 to regulate prostaglandins synthesis in rat chondrocytes stimulated with interleukin-1β (IL-1β). We demonstrated that 15d-PGJ2 , but not the high-affinity PPARγ ligand rosiglitazone, decreased almost completely PGE2 synthesis and mPGES-1 expression. The inhibitory potency of 15d-PGJ2 was unaffected by changes in PPARγ expression and resulted from inhibition of NF-κB nuclear binding and IκBα sparing, secondary to reduced phosphorylation of IKKβ. Consistently with 15d-PGJ2 being a putative endogenous regulator of the inflammatory reaction if synthesized in sufficient amounts, the present data confirm the variable PPARγ-dependency of its effects in joint cells while underlining possible species and cell types specificities. Show more

Keywords: PPARγ, eicosanoids, 15-deoxy-$\Delta^{12,14}$-prostaglandin J$_{2}$, thiazolidinediones, chondrocyte, synoviocyte

Citation: Biorheology, vol. 43, no. 3-4, pp. 561-575, 2006

Authors: Domagala, F. | Martin, G. | Bogdanowicz, P. | Ficheux, H. | Pujol, J.-P.

Article Type: Research Article

Abstract: In the present report we have shown that bovine articular chondrocytes cultured in low oxygen tension, i.e. in conditions mimicking their hypoxic in vivo environment, respond to IL-1β (10 ng/ml) by an increased DNA binding activity of NF-κB and AP-l transcription factors. Incubation of the cells with 10−5 M Rhein, the active metabolite of Diacerhein, for 24 h was found to reduce this activity particularly in the case of AP-1. Mitogen activated kinases (ERK-1 and ERK-2) were activated by exposure of the chondrocytes to a 1 h treatment with IL-1β. This effect was greater in hypoxia (3% O2 ) …than in normoxia (21% O2 ). Rhein was capable of reducing the IL-1β-stimulated ERK1/ERK2 pathway whatever the tension of oxygen present in the environment. The mRNA steady-state levels of collagen type II (COL2A1) and aggrecan core protein were found to be significantly increased by a 24-h treatment with 10−5 M Rhein. This stimulating effect was also observed in the presence of IL-1β, suggesting that the drug could prevent or reduce the IL-1β-induced inhibition of extra cellular matrix synthesis. IL-1-induced collagenase (MMP1) expression was significantly decreased by Rhein under the same conditions. In conclusion, Rhein can effectively inhibit the IL-1-activated MAPK pathway and the binding of NF-κB and AP-1 transcription factors, two key factors involved in the expression of several pro-inflammatory genes by chondrocytes. In addition, the drug can reduce the procatabolic effect of the cytokine, by reducing the MMP1 synthesis, and enhance the synthesis of matrix components, such as type II collagen and aggrecan. These results may explain the anti-osteoarthritic properties of Rhein and its disease-modifying effects on OA cartilage, in spite of the absence of inhibition at prostaglandin level. Show more

Citation: Biorheology, vol. 43, no. 3-4, pp. 577-587, 2006

Authors: Brandt, Kenneth D.

Article Type: Research Article

Citation: Biorheology, vol. 43, no. 3-4, pp. 589-594, 2006

Authors: de Isla, N.G. | Yang, J.W. | Huselstein, C. | Muller, S. | Stoltz, J.F.

Article Type: Research Article

Abstract: Several factors are known to be involved in the destruction of the articular cartilage. Interleukin-1 (IL-1) plays an important role in the pathogenesis of osteoarthritis (OA) either directly or through the stimulation of catabolic factors. The action of IL-1 on articular cartilage is multifaceted and it most likely plays an important role in the mechanism of cartilage destruction. IL-1 suppresses the synthesis of the cartilage matrix components and promotes the degradation of cartilage matrix macromolecules. Diacerein is an anthraquinone molecule that has been shown to reduce the severity of OA, both in man and in animal models. The present study …was designed to evaluate in vitro effects of diacerein on IL-1β expression in LPS or IL-1α stimulated chondrocytes. Intracellular IL-1β production was analysed in articular chondrocytes cultured in monolayer or in alginate 3D-biosystems in the presence of lipopolysaccharide (LPS) or IL-1α, with or without diacerein. The results show that LPS and IL-1α increase intracellular IL-1β and Diacerein inhibited LPS-induced and IL-1α induced IL-1β production by articular chondrocytes. Moreover, the effect of mechanical stimulation was analysed. An inhibitory effect of DAR at therapeutic concentrations on IL-1β production in articular chondrocytes is suggested. Show more

Keywords: Articular chondrocyte, interleukin-1β, diacerein, mechanical stress, osteoarthritis

Citation: Biorheology, vol. 43, no. 3-4, pp. 595-601, 2006

Authors: Buckwalter, Joseph A. | Martin, James A. | Brown, Thomas D.

Article Type: Research Article

Abstract: Osteoarthritis, the clinical syndrome of joint pain and dysfunction due to joint degeneration, is among the most frequent and symptomatic medical problems for middle aged and older people, and it is the most common cause of long term disability in most populations of people over 65. Currently there are no effective methods of preventing or curing osteoarthritis. Post-traumatic OA, the joint degeneration, pain and dysfunction that develop following joint injury, is the form of OA that is most directly related to elevated articular surface contact stress. However, mechanical stress that exceeds the tolerance of the articular surface can cause or …accelerate the progression of joint degeneration in all individuals and in all synovial joints. In some patients, decreasing mechanical forces on degenerated joint surfaces stimulates formation of a new biologic articular surface. The advances in understanding of the effects of mechanical forces on chondrocytes and cartilage presented and discussed at the 4th Symposium on Mechanobiology: Cartilage and Chondrocyte will help in the efforts to develop new methods of preventing and treating osteoarthritis. Show more

Citation: Biorheology, vol. 43, no. 3-4, pp. 603-609, 2006