Engineering Lubrication in Articular Cartilage

Department of Orthopaedic Surgery, Lawrence Ellison Center for Tissue Regeneration and Repair, School of Medicine, University of California, Davis, Sacramento, California, USA.
Tissue Engineering Part B Reviews (Impact Factor: 4.64). 09/2011; 18(2):88-100. DOI: 10.1089/ten.TEB.2011.0394
Source: PubMed


Despite continuous progress toward tissue engineering of functional articular cartilage, significant challenges still remain. Advances in morphogens, stem cells, and scaffolds have resulted in enhancement of the bulk mechanical properties of engineered constructs, but little attention has been paid to the surface mechanical properties. In the near future, engineered tissues will be able to withstand and support the physiological compressive and tensile forces in weight-bearing synovial joints such as the knee. However, there is an increasing realization that these tissue-engineered cartilage constructs will fail without the optimal frictional and wear properties present in native articular cartilage. These characteristics are critical to smooth, pain-free joint articulation and a long-lasting, durable cartilage surface. To achieve optimal tribological properties, engineered cartilage therapies will need to incorporate approaches and methods for functional lubrication. Steady progress in cartilage lubrication in native tissues has pushed the pendulum and warranted a shift in the articular cartilage tissue-engineering paradigm. Engineered tissues should be designed and developed to possess both tribological and mechanical properties mirroring natural cartilage. In this article, an overview of the biology and engineering of articular cartilage structure and cartilage lubrication will be presented. Salient progress in lubrication treatments such as tribosupplementation, pharmacological, and cell-based therapies will be covered. Finally, frictional assays such as the pin-on-disk tribometer will be addressed. Knowledge related to the elements of cartilage lubrication has progressed and, thus, an opportune moment is provided to leverage these advances at a critical step in the development of mechanically and tribologically robust, biomimetic tissue-engineered cartilage. This article is intended to serve as the first stepping stone toward future studies in functional tissue engineering of articular cartilage that begins to explore and incorporate methods of lubrication.

Download full-text


Available from: Kyriacos Athanasiou
  • Source
    • "SZP contributes to boundary lubrication and protects the articular surface from cell and protein adhesion [29-31]. A main objective in tissue engineering of articular cartilage remains achieving lubrication [32]. TGF-β1 may be used to enhance articular chondrocyte protein synthesis in vitro but its effect in costochondral cells, specifically at a higher dose, requires further examination. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Costochondral cells may be isolated with minimal donor site morbidity and are unaffected by pathologies of the diarthrodial joints. Identification of optimal exogenous stimuli will allow abundant and robust hyaline articular cartilage to be formed from this cell source. In a three factor, two level full factorial design, the effects of hydrostatic pressure (HP), transforming growth factor beta1 (TGF-beta1), and chondroitinase ABC (C-ABC), and all resulting combinations, were assessed in third passage expanded, redifferentiated costochondral cells. After 4 wks, the new cartilage was assessed for matrix content, superficial zone protein (SZP), and mechanical properties. Hyaline articular cartilage was generated, demonstrating the presence of type II collagen and SZP, and the absence of type I collagen. TGF-beta1 upregulated collagen synthesis by 175% and glycosaminoglycan synthesis by 75%, resulting in a nearly 200% increase in tensile and compressive moduli. C-ABC significantly increased collagen content, and fibril density and diameter, leading to a 125% increase in tensile modulus. Hydrostatic pressure increased fibril diameter by 30% and tensile modulus by 45%. Combining TGF-beta1 with C-ABC synergistically increased collagen content by 300% and tensile strength by 320%, over control. No significant differences were observed between C-ABC/TGF-beta1 dual treatment and HP/C-ABC/TGF-beta1. Employing biochemical, biophysical, and mechanical stimuli generated robust hyaline articular cartilage with a tensile modulus of 2 MPa and a compressive instantaneous modulus of 650 kPa. Using expanded, redifferentiated costochondral cells in the self-assembling process allows for recapitulation of robust mechanical properties, and induced SZP expression, key characteristics of functional articular cartilage.
    Full-text · Article · Dec 2013 · Arthritis research & therapy
    • "Articular cartilage is the bearing surface of synovial joints. It comprises a relatively small number of cells (chondrocytes) and an abundant extra cellular matrix of collagen, proteoglycan and water (McNary et al., 2012; Shepherd and Seedhom, 1997). This structure makes articular cartilage a viscoelastic material (Fulcher et al., 2009). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Articular cartilage is the bearing surface of synovial joints and plays a crucial role in the tribology to enable low friction joint movement. A detailed understanding of the surface roughness of articular cartilage is important to understand how natural joints behave and the parameters required for future joint replacement materials. Bovine articular cartilage on bone samples was prepared and the surface roughness was measured using scanning electron microscopy stereoscopic imaging at magnifications in the range 500× to 2000×. The surface roughness (two-dimensional, R(a), and three-dimensional, S(a)) of each sample was then measured using atomic force microscopy (AFM). For stereoscopic imaging the surface roughness was found to linearly increase with increasing magnification. At a magnification of 500× the mean surface roughness, R(a), was in the range 165.4±5.2nm to 174±39.3nm; total surface roughness S(a) was in the range 183-261nm. The surface roughness measurements made using AFM showed R(a) in the range 82.6±4.6nm to 114.4±44.9nm and S(a) in the range 86-136nm. Values obtained using SEM stereo imaging were always larger than those obtained using AFM. Stereoscopic imaging can be used to investigate the surface roughness of articular cartilage. The variations seen between measurement techniques show that when making comparisons between the surface roughness of articular cartilage it is important that the same technique is used.
    No preview · Article · Jun 2012 · Micron
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cartilage lesions of the knee, talus, ankle and hip generate chronic symptoms represented by pain associated to weight bearing, stiffness, locking and swelling of damaged joints that reduce the ability to walk, work and to carry out sports range of motion. Cartilage degeneration reduces the quality of life and has a huge impact on public health. Articular cartilage repair is a very hot topic for biomedical sciences and has evolving rapidly due to groundbreaking advances in tissue engineering driven by cell biology and biomaterials. The study here analyzes the publications and patents of cartilage tissue engineering to determine the patterns of the new therapies possibilities of cartilage repair to replace joint arthroplasties in the future. Findings, based on scientific and technological outputs, show that new clinical applications of Autologous Chondrocyte Implantation (ACI) and Chondrogenic Differentiation of Mesenchymal Stem Cells (MSCs) are fruitful approaches for cartilage regenerative medicine that should replace the artificial joint replacement in not-too-distant future. In fact, these new technological paradigms repair the cartilage with more efficacy and have been generating a revolution in clinical practice due to benefits in terms of higher quality of life.
    Full-text · Article · Dec 2012 · Health and Technology
Show more