Biorheology - Volume 39, issue 1-2

Authors: van de Lest, Chris H.A. | Brama, Pieter A.J. | van Weeren, P. René

Article Type: Research Article

Abstract: An overview is given of the direct and long‐term effects of exercise on the biochemical characteristics of cartilage and subchondral bone, and on the metabolic activity of chondrocytes in the juvenile horse. In the experimental setup 43 foals were reared until weaning at 5 months of age under similar conditions, except for the type and amount of exercise. Fifteen foals remained at pasture (Pasture group and also control group), 14 foals were kept in box stalls (Box group), and 14 foals were kept in the same box stalls but were subjected daily to an increasing number of gallop sprints (Training …group). After weaning 8 foals from each group were euthanised. All remaining 19 animals were housed together in a loose box with access to a small paddock to study a possible reversibility of exercise‐induced effects. Post mortem subchondral bone and cartilage samples were collected and analysed for bone morphogenic enzymes, matrix composition, chondrocyte metabolic activity, and bone mineral density. It resulted that lack of exercise leads to a retardation of the normal development of the joint. This is largely compensated for when afterwards a more normal exercise regimen is followed. Most parameters in the Training group approximated those of the pastured foals at age 5 months. However, at age 11 months there were indications for a reduced performance of the investigated tissues in this group. It is concluded that regular, sub‐maximal loading, as occurred in the Pasture group, seems best for an optimal development of the musculoskeletal tissues. The combination of short bouts of heavy exercise superimposed on a basic box rest regimen appears to have adverse effects on long‐term viability of the tissues and may hence lead to an impaired resistance to injury. Show more

Citation: Biorheology, vol. 39, no. 1-2, pp. 183-191, 2002

Authors: Bellucci, Giordano | Seedhom, Bahaa B.

Article Type: Research Article

Abstract: Although fatigue has been implicated in cartilage failure there are only two studies by the same author, and in both of which cartilage was tested in the direction parallel to the collagen orientation in the surface layer. In the present work articular cartilage was tested also along the perpendicular direction, being the direction in which cartilage possesses lower tensile strength. Specimens were tested under cyclic tensile load. Number of cycles at failure was recorded as well as elongation of the specimen. To date 72 specimens have been tested all from one knee joint. The number of cycles to …failure ranged between two and 1.5 million. The surface and deep layers have better fatigue properties whether tested in the parallel or the perpendicular direction, while the middle layer was far weaker. Better fatigue behaviour was observed with specimens tested in parallel than in perpendicular direction to the fibres. Show more

Citation: Biorheology, vol. 39, no. 1-2, pp. 193-199, 2002

Authors: Jouzeau, Jean‐Yves | Pacquelet, Sandrine | Boileau, Christelle | Nedelec, Emmanuelle | Presle, Nathalie | Netter, Patrick | Terlain, Bernard

Article Type: Research Article

Abstract: Nitric oxide (NO) is thought to mediate most effects of interleukin‐1 (IL‐1) on cartilage. In vitro evidence includes the decreased synthesis of extracellular matrix components, the abnormal cell renewal, the decreased production of IL‐1 receptor antagonist, the induction of apoptosis and the enhanced sensitivity of chondrocytes to oxidative stress. Studies in NOS2−/− mice or administration of NO synthase inhibitors in animal models of joint disorders have confirmed its potent pathophysiological role in cartilage. Using L‐NMMA (1 mM), as a NO synthase inhibitor, and CuDips (10 μM), as a SOD mimetic, we provide evidence that the inhibitory potency of IL‐1β …on proteoglycan synthesis and its stimulating effect on COX‐2 activity depend both on NO and O2 −. production. Peroxynitrite formation is further demonstrated by the occurrence of 3‐nitrotyrosines in chondrocytes stimulated in vitro with 2.5 ng/ml IL‐1 and in femoral condyles of rats injected locally with 1 μg IL‐1. Preliminary data suggest that such contribution of reactive oxygen species is not shared in common by IL‐17, another NO‐producing cytokine. We conclude that superoxide is a key modulator of NO‐mediated effects in chondrocyte stimulated with IL‐1 and that a combined therapy with NO synthase inhibitors and antioxidants may be promising for a full cartilage protection. Show more

Keywords: Interleukin‐1, chondrocytes, proteoglycans, superoxide, nitric oxide, NO synthase inhibitors

Citation: Biorheology, vol. 39, no. 1-2, pp. 201-214, 2002

Authors: van Osch, Gerjo J.V.M. | Mandl, Erik W. | Marijnissen, Willem J.C.M. | van der Veen, Simone W. | Verwoerd‐Verhoef, Henriette L. | Verhaar, Jan A.N.

Article Type: Research Article

Abstract: Tissue engineering of cartilage consists of two steps. Firstly, the cells from a small biopsy of patient's own tissue have to be multiplied. During this multiplication process they lose their cartilage phenotype. In the second step, these cells have to be stimulated to re‐express their cartilage phenotype and produce cartilage matrix. Growth factors can be used to improve cell multiplication, redifferentiation and production of matrix. The choice of growth factors should be made for each phase of the tissue engineering process separately, taking into account cell phenotype and the presence of extracellular matrix. This paper demonstrates some examples of the …use of growth factors to increase the amount, the quality and the assembly of the matrix components produced for cartilage tissue engineering. In addition it shows that the “culture history” (e.g., addition of growth factors during cell multiplication or preculture period in a 3‐dimensional environment) of the cells influences the effect of growth factor addition. The data demonstrate the potency as well as the limitations of the use of growth factors in cartilage tissue engineering. Show more

Citation: Biorheology, vol. 39, no. 1-2, pp. 215-220, 2002

Authors: Brandt, Kenneth D.

Article Type: Research Article

Abstract: Animal models have proved to be of considerable importance in elucidating mechanisms underlying joint damage in osteoarthritis (OA) and providing proof of concept in the development of pharmacologic and biologic agents that may modify structural damage in the OA joint. The utility of animal models in predicting the response to an intervention with a drug or biologic agent in humans, however, can be established only after evidence is obtained of a positive effect of the agent in humans. To date, no agent has been shown unequivocally to have such an effect, although diacerhein and glucosamine have recently been reported to …lower the rate of loss of articular cartilage in patients with hip OA and knee OA, respectively, based on measurements of the rate of joint space narrowing in plain radiographs. Furthermore, the predominant manifestation of OA – and the feature that leads people with radiographic changes of the disease to decide to seek medical attention and contributes to the enormous medicoeconomic and socioeconomic burden imposed by the disease – is joint pain. Notably, none of the animal models of OA is a good indicator of the analgesic effects of pharmacologic agents. Indeed, it should not be assumed a priori that reduction in the rate of progression of joint damage in OA will be associated with a reduction in joint pain. Show more

Citation: Biorheology, vol. 39, no. 1-2, pp. 221-235, 2002

Authors: Fernandes, Julio C. | Martel‐Pelletier, Johanne | Pelletier, Jean‐Pierre

Article Type: Research Article

Abstract: Morphological changes observed in OA include cartilage erosion as well as a variable degree of synovial inflammation. Current research attributes these changes to a complex network of biochemical factors, including proteolytic enzymes, that lead to a breakdown of the cartilage macromolecules. Cytokines such as IL‐1 and TNF‐alpha produced by activated synoviocytes, mononuclear cells or by articular cartilage itself significantly up‐regulate metalloproteinases (MMP) gene expression. Cytokines also blunt chondrocyte compensatory synthesis pathways required to restore the integrity of the degraded extrecellular matrix (ECM). Moreover, in OA synovium, a relative deficit in the production of natural antagonists of the IL‐1 receptor (IL‐1Ra) …has been demonstrated, and could possibly be related to an excess production of nitric oxide in OA tissues. This, coupled with an upregulation in the receptor level, has been shown to be an additional enhancer of the catabolic effect of IL‐1 in this disease. IL‐1 and TNF‐α significantly up‐regulate MMP‐3 steady‐state mRNA derived from human synovium and chondrocytes. The neutralization of IL‐1 and/or TNF‐α up‐regulation of MMP gene expression appears to be a logical development in the potential medical therapy of OA. Indeed, recombinant IL‐1receptor antagonists (ILRa) and soluble IL‐1 receptor proteins have been tested in both animal models of OA for modification of OA progression. Soluble IL‐1Ra suppressed MMP‐3 transcription in the rabbit synovial cell line HIG‐82. Experimental evidence showing that neutralizing TNF‐α suppressed cartilage degradation in arthritis also support such strategy. The important role of TNF‐α in OA may emerge from the fact that human articular chondrocytes from OA cartilage expressed a significantly higher number of the p55 TNF‐alpha receptor which could make OA cartilage particularly susceptible to TNF‐alpha degradative stimuli. In addition, OA cartilage produces more TNF‐α and TNF∠α convertase enzyme (TACE) mRNA than normal cartilage. By analogy, an inhibitor to the p55 TNF‐α receptor may also provide a mechanism for abolishing TNF‐α‐induced degradation of cartilage ECM by MMPs. Since TACE is the regulator of TNF‐α activity, limiting the activity of TACE might also prove efficacious in OA. IL‐1 and TNF‐α inhibition of chondrocyte compensatory biosynthesis pathways which further compromise cartilage repair must also be dealt with, perhaps by employing stimulatory agents such as transforming growth factor‐beta or insulin‐like growth factor‐I. Certain cytokines have antiinflammatory properties. Three such cytokines – IL‐4, IL‐10, and IL‐13 – have been identified as able to modulate various inflammatory processes. Their antiinflammatory potential, however, appears to depend greatly on the target cell. Interleukin‐4 (IL‐4) has been tested in vitro in OA tissue and has been shown to suppress the synthesis of both TNF‐α and IL‐1β in the same manner as low‐dose dexamethasone. Naturally occurring antiinflammatory cytokines such as IL‐10 inhibit the synthesis of IL‐1 and TNF‐α and can be potential targets for therapy in OA. Augmenting inhibitor production in situ by gene therapy or supplementing it by injecting the recombinant protein is an attractive therapeutic target, although an in vivo assay in OA is not available, and its applicability has yet to be proven. Similarly, IL‐13 significantly inhibits lipopolysaccharide (LPS)‐induced TNF‐α production by mononuclear cells from peripheral blood, but not in cells from inflamed synovial fluid. IL‐13 has important biological activities: inhibition of the production of a wide range of proinflammatory cytokines in monocytes/macrophages, B cells, natural killer cells and endothelial cells, while increasing IL‐1Ra production. In OA synovial membranes treated with LPS, IL‐13 inhibited the synthesis of IL‐1β, TNF‐α and stromelysin, while increasing IL‐1Ra production. In summary, modulation of cytokines that control MMP gene up‐regulation would appear to be fertile targets for drug development in the treatment of OA. Several studies illustrate the potential importance of modulating IL‐1 activity as a means to reduce the progression of the structural changes in OA. In the experimental dog and rabbit models of OA, we have demonstrated that in vivo intraarticular injections of the IL‐Ra gene can prevent the progression of structural changes in OA. Future directions in the research and treatment of osteoarthritis (OA) will be based on the emerging picture of pathophysiological events that modulate the initiation and progression of OA. Show more

Keywords: OA, proinflammatory cytokines, antiinflammatory cytokines, cytokine antagonists

Citation: Biorheology, vol. 39, no. 1-2, pp. 237-246, 2002

Authors: Bluteau, G. | Gouttenoire, J. | Conrozier, T. | Mathieu, P. | Vignon, E. | Richard, M. | Herbage, D. | Mallein‐Gerin, F.

Article Type: Research Article

Abstract: Osteoarthritis (OA) is the most common of all joint diseases to affect mankind and is characterized by the degradation of articular cartilage. The low availability of normal and pathologic human cartilage and the inability to study the early stages of the disease in humans has led to the development of numerous animal models of OA. The aim of our study was to establish gene expression profiles during the progression of a rabbit model of OA induced by anterior cruciate ligament (ACL) section. Semiquantitative RT–PCR was used to follow expression of several relevant molecules (type II and X collagens, aggrecan, osteonectin, …βig‐h3, BiP, TIMP‐1, MMP‐1, ‐3, ‐13, aggrecanase‐1, ‐2) during development of OA in articular cartilage. In parallel, we monitored the activities of collagenase, caseinase, phospholipase A2 and glycosyltransferases (xylosyl‐, galactosyl‐, glucuronyl‐ and N‐acetyl‐galactosaminyl‐transferase). Novel cDNA clones for rabbit type X collagen, aggrecanase‐1 and ‐2, osteonectin and BiP were constructed to obtain species‐specific primers. Ours result show that MMP‐13 (collagenase‐3) gene expression increased dramatically early after ACL surgery and remained high thereafter. An increase in MMP‐1 (collagenase‐1) and MMP‐3 expression was also noted with an absence of variation for TIMP‐1 expression. In addition, the global MMPs activities paralleled the MMP gene expression. These data together characterize at the molecular level the evolution of OA in this rabbit model. Furthermore, we have undertaken a search for identifying differentially expressed genes in normal and OA cartilage in this model, by differential display RT–PCR. We present here preliminary results with the determination of the best technical conditions to obtain reproducible electrophoresis patterns of differential display RT–PCR. Show more

Citation: Biorheology, vol. 39, no. 1-2, pp. 247-258, 2002

Authors: Vunjak‐Novakovic, G. | Obradovic, B. | Martin, I. | Freed, L.E.

Article Type: Research Article

Abstract: Functional tissue engineering of cartilage involves the use of bioreactors designed to provide a controlled in vitro environment that embodies some of the biochemical and physical signals known to regulate chondrogenesis. Hydrodynamic conditions can affect in vitro tissue formation in at least two ways: by direct effects of hydrodynamic forces on cell morphology and function, and by indirect flow‐induced changes in mass transfer of nutrients and metabolites. In the present work, we discuss the effects of three different in vitro environments: static flasks (tissues fixed in place, static medium), mixed flasks (tissues fixed in place, unidirectional turbulent flow) and rotating …bioreactors (tissues dynamically suspended in laminar flow) on engineered cartilage constructs and native cartilage explants. As compared to static and mixed flasks, dynamic laminar flow in rotating bioreactors resulted in the most rapid tissue growth and the highest final fractions of glycosaminoglycans and total collagen in both tissues. Mechanical properties (equilibrium modulus, dynamic stiffness, hydraulic permeability) of engineered constructs and explanted cartilage correlated with the wet weight fractions of glycosaminoglycans and collagen. Current research needs in the area of cartilage tissue engineering include the utilization of additional physiologically relevant regulatory signals, and the development of predictive mathematical models that enable optimization of the conditions and duration of tissue culture. Show more

Citation: Biorheology, vol. 39, no. 1-2, pp. 259-268, 2002

Authors: Loeuille, Damien | Olivier, Pierre | Watrin, Astrid | Grossin, Laurent | Gonord, Patrick | Guillot, Geneviève | Etienne, Stéphanie | Blum, Alain | Netter, Patrick | Gillet, Pierre

Article Type: Research Article

Abstract: The MR aspect of articular cartilage, that reflects the interactions between protons and macromolecular constituents, is affected by the intrinsic tissue structure (water content, the content of matrix constituents, collagen network organization), imager characteristics, and acquisition parameters. On the T1‐weighted sequences, the bovine articular cartilage appears as an homogeneous tissue in high signal intensity, whatever the age of animals considered, whereas on the T2‐weighted sequences, the articular bovine cartilage presents variations of its imaging pattern (laminar appearance) well correlated to the variations of its histological and biochemical structure. The T2 relaxation time measurement (T2 mapping), which reflects quantitatively the signal …intensity variations observed on T2 weighted sequences, is a way to evaluate more precisely the modifications of cartilage structure during the aging and maturation processes (rat's study). This technique so far confined to experimental micro‐imagers is now developed on clinical imagers. Consequently, it may permit to depict the early stages of osteoarthritic disease (OA) or to evaluate the chondroprotective effect of drugs. Show more

Keywords: Cartilage, MRI, aging, extracellular matrix, biochemistry, histological correlations

Citation: Biorheology, vol. 39, no. 1-2, pp. 269-276, 2002

Authors: Gigant‐Huselstein, C. | Dumas, D. | Payan, E. | Muller, S. | Bensoussan, D. | Netter, P. | Stoltz, J.F.

Article Type: Research Article

Abstract: The purpose of the present study was to investigate the intracellular IL‐1β production and β1 integrins (α4/β1 and α5/β1) expression on chondrocytes. Chondroytes monolayer (human chondrosarcoma cell line HEM‐C55) were incubated for 12, 24 and 48 hours in the presence of Tumor Necrosis Factor‐α (TNF‐α, Sigma, France) or recombinant human IL‐1α (rh‐IL1α, Becton Dickinson, France). After direct immunolabelling, cells were either analyzed on FACScan flow cytometer (Becton Dickinson, France), or observed under an epi‐fluorescence inverted microscope equipped with the CellScan EPRTM optical scanning acquisition system (IPLab‐Scanalytics, USA). We found that the IL‐1β mean fluorescence intensity in flow cytometry …and in 3D microscopy was increased in the presence of TNF‐α or rh‐IL‐1α, and α4/β1 or α5/β1 expression was higher on stimulated cells than on control cells. On the other hand, we have evaluated the in vitro effects of rhein (10−5 M, Negma, France), an active metabolite of diacerein, on the intracellular IL‐1β and β1 integrins expressed by stimulated or no‐stimulated chondrocytes. The results indicated that rhein leads to a reduction of IL‐1β synthesis whereas a weak decrease of β1 integrins receptors expression is observed. From this study, it seems that rhein partially reduce cytokine‐induced intracellular IL‐1β production, and it has a weak action on α4/β1 or α5/β1 receptors. Show more

Citation: Biorheology, vol. 39, no. 1-2, pp. 277-285, 2002