Cartilage in normal and osteoarthritis conditions

Role of glucose as a modulator of anabolic and catabolic gene expression in normal and osteoarthritic human chondrocytes

“…These unique properties are due to the structural organization of the main macromolecules that compose the cartilage extracellular matrix, namely collagens and proteoglycans. Chondrocytes, the only cell type present in articular cartilage, are embedded in the extracellular matrix and are responsible for maintaining its homeostasis by ensuring the synthesis and turnover of its components [Martel-Pelletier et al, 2008;Goldring and Marcu, 2009].…”

“…These degrade the matrix components causing progressive cartilage destruction, the main feature of OA [Martel-Pelletier et al, 2008;Goldring and Marcu, 2009].…”

“…These unique properties are due to the structural organization of the main macromolecules that compose the cartilage extracellular matrix, namely collagens and proteoglycans. Chondrocytes, the only cell type present in articular cartilage, are embedded in the extracellular matrix and are responsible for maintaining its homeostasis by ensuring the synthesis and turnover of its components [Martel-Pelletier et al, 2008;Goldring and Marcu, 2009].Cartilage matrix homeostasis involves a dynamic balance between a variety of signals that modulate chondrocyte functions, namely mechanical forces, cytokines and growth factors and cellmatrix interactions, some favoring an anabolic program and others stimulating catabolic responses. Aging and mechanical stress of joints are major risk factors for osteoarthritis (OA), but growing evidence indicates that metabolic factors play an important role in disease development and progression.…”

“…The last is especially important since it can act in articular chondrocytes in an autocrine and/or paracrine way, inducing anabolic effects and inhibiting catabolic responses. More specifically, TGF has been shown to stimulate proteoglycans, collagen type II [Miyazaki et al, 2000;Martel-Pelletier et al, 2008] and TIMPs expression [Wang et al, 2002], while reversing some of the IL-1-induced catabolic effects [Seifarth et al, 2009].Besides these well-characterized stimuli, chondrocytes respond to and are influenced by other signals. Among these, the extracellular glucose concentration, either increased or decreased, has been shown to directly affect some chondrocyte functions [Kelley et al, 1999;Richardson et al, 2003;McNulty et al, 2005].…”

Does Intraarticular Inflammation Predict Biomechanical Cartilage Properties?

“…Cartilage remodeling processes are highly active under inflammatory conditions [37]. The increased turnover rate and atypical composition of newly synthesized extracellular matrix appear to compromise the quality of the extracellular cartilage matrix [27,29]. These compositional changes affect the mechanical stability of articular cartilage which ultimately leads to fibrillation and fissure formation [40,44].…”