logo
    Background: Insufficient cell numbers still present a challenge for articular cartilage repair. Converting heterotopic auricular chondrocytes by extracellular matrix may be the solution. Hypothesis: Specific extracellular matrix may convert the phenotype of auricular chondrocytes toward articular cartilage for repair. Study Design: Controlled laboratory study. Methods: For in vitro study, rabbit auricular chondrocytes were cultured in monolayer for several passages until reaching status of dedifferentiation. Later, they were transferred to chondrogenic type II collagen (Col II)–coated plates for further cell conversion. Articular chondrogenic profiles, such as glycosaminoglycan deposition, articular chondrogenic gene, and protein expression, were evaluated after 14-day cultivation. Furthermore, 3-dimensional constructs were fabricated using Col II hydrogel-associated auricular chondrocytes, and their histological and biomechanical properties were analyzed. For in vivo study, focal osteochondral defects were created in the rabbit knee joints, and auricular Col II constructs were implanted for repair. Results: The auricular chondrocytes converted by a 2-step protocol expressed specific profiles of chondrogenic molecules associated with articular chondrocytes. The histological and biomechanical features of converted auricular chondrocytes became similar to those of articular chondrocytes when cultivated with Col II 3-dimensional scaffolds. In an in vivo animal model of osteochondral defects, the treated group (auricular Col II) showed better cartilage repair than did the control groups (sham, auricular cells, and Col II). Histological analyses revealed that cartilage repair was achieved in the treated groups with abundant type II collagen and glycosaminoglycans syntheses rather than elastin expression. Conclusion: The study confirmed the feasibility of applying heterotopic chondrocytes for cartilage repair via extracellular matrix–induced cell conversion. Clinical Relevance: This study proposes a feasible methodology to convert heterotopic auricular chondrocytes for articular cartilage repair, which may serve as potential alternative sources for cartilage repair.
    Chondrogenesis
    Articular cartilage repair
    SOX9
    Type II collagen
    Matrix (chemical analysis)
    Citations (28)
    The main functions of articular cartilages are load-bearing and reducing friction of the articular surfaces. Because the capacity of articular cartilage to repair is limited, many attempts have been made to repair articular cartilage defects, which include transplantations of various tissues or cells. Within them, autologous cultured chondrocyte or autologous bone marrow mesenchymal cell transplantations are reported to be useful methods to repair articular cartilage defects. Here, we introduce these methods of tissue engineering and gene therapy, which are expected to become new treatments of articular cartilage defects.
    Articular cartilage repair
    Autologous chondrocyte implantation
    Citations (0)
    Abstract Articular cartilage repair after injury is a great challenge worldwide due to its nerveless and avascular features. Tissue engineering is proposed as a promising alternative for cartilage regeneration. In this study, an adenoviral vector carrying the transforming growth factor‐β3 (TGF‐β3) gene was constructed and introduced into dedifferentiated chondrocytes, which were then cocultured with ATDC5 cells in an alginate hydrogel system. The results showed that the experimental groups exhibited better cell viability and higher levels of cartilage‐related genes than the control groups. In this coculture system, the chondrogenic differentiation of ATDC5 cells was effectively induced by TGF‐β3 and other latent cytokines that were produced by the transfected chondrocytes. Thus, this method can avoid the degradation of exogenous TGF‐β3, and it can protect ATDC5 cells during virus transfection to maintain cell viability and chondrogenic differentiation capability. Taken together, this study provides fresh insights for applying this genetically manipulated coculture system to cartilage repair in the future.
    Chondrogenesis
    Articular cartilage repair
    Viability assay
    SOX9
    Citations (6)
    Abstract The repair of joint surface defects remains a clinical challenge, as articular cartilage has a limited healing response. Despite this, articular cartilage does have the capacity to grow and remodel extensively during pre‐ and post‐natal development. As such, the elucidation of developmental mechanisms, particularly those in post‐natal animals, may shed valuable light on processes that could be harnessed to develop novel approaches for articular cartilage tissue engineering and/or regeneration to treat injuries or degeneration in adult joints. Much has been learned through mouse genetics regarding the embryonic development of joints. This knowledge, as well as the less extensive available information regarding post‐natal joint development is reviewed here and discussed in relation to their possible relevance to future directions in cartilage tissue repair and regeneration. J. Cell. Biochem. 107: 383–392, 2009. © 2009 Wiley‐Liss, Inc.
    Chondrogenesis
    Citations (92)
    Hunter's observation in 1743 that cartilage "once destroyed, is not repaired," has not essentially changed for 250 years. At present, there is no well-established procedure for the repair of cartilage defect with articular cartilage, which has the same biochemical and biomechanical properties as the surrounding normal intact cartilage. In 1994, transplantation of human autologous chondrocytes in suspension, as reported by Brittberg et al., provided a potential procedure for articular cartilage repair. We have improved their procedure and developed a new technique which creates new cartilage-like tissue by cultivating autologous chondrocytes embedded in Atelocollagen gel for 3 weeks before transplantation. These improvements maintained the chondrocyte phenotype, evenly distributed chondrocytes throughout the osteochondral defects, and decreased the risk of leakage of grafted chondrocytes into the defects. Good clinical results suggest that this technique should be a promising procedure for repairing articular cartilage defect.
    Articular cartilage repair
    Cartilage damage
    Autologous chondrocyte implantation
    Articular cartilage has a limited capacity for repair. Repair of articular cartilage has been an important theme for orthopaedic surgeons. With the progress of tissue engineering in the treatment of articular cartilage injury, we can obtain good results, to some extent, by cell transplantations. This review summarized the present status of the treatment of articular cartilage injuries by cell transplantations.
    Articular cartilage repair
    Citations (0)
    Regenerative medicine strategies have increasingly focused on skeletal stem cells (SSCs), in response to concerns such as donor site morbidity, dedifferentiation and limited lifespan associated with the use of articular chondrocytes for cartilage repair. The suitability of SSCs for cartilage regeneration, however, remains to be fully determined. This study has examined the chondrogenic potential of human STRO-1-immunoselected SSCs (STRO-1(+) SSCs), in comparison to human articular chondrocytes (HACs), by utilising two bioengineering strategies, namely "scaffold-free" three-dimensional (3-D) pellet culture and culture using commercially available, highly porous, 3-D scaffolds with interconnected pore networks. STRO-1(+) SSCs were isolated by magnetic-activated cell sorting from bone marrow samples of haematologically normal osteoarthritic individuals following routine hip replacement procedures. Chondrocytes were isolated by sequential enzymatic digestion of deep zone articular cartilage pieces dissected from femoral heads of the same individuals. After expansion in monolayer cultures, the harvested cell populations were centrifuged to form high-density 3-D pellets and also seeded in the 3-D scaffold membranes, followed by culture in serum-free chondrogenic media under static conditions for 21 and 28 days, respectively. Chondrogenic differentiation was determined by gene expression, histological and immunohistochemical analyses. Robust cartilage formation and expression of hyaline cartilage-specific markers were observed in both day-21 pellets and day-28 explants generated using HACs. In comparison, STRO-1(+) SSCs demonstrated significantly lower chondrogenic differentiation potential and a tendency for hypertrophic differentiation in day-21 pellets. Culture of STRO-1(+) SSCs in the 3-D scaffolds improved the expression of hyaline cartilage-specific markers in day-28 explants, however, was unable to prevent hypertrophic differentiation of the SSC population. The advantages of application of SSCs in tissue engineering are widely recognised; the results of this study, however, highlight the need for further development of cell culture protocols that may otherwise limit the application of this stem cell population in cartilage bioengineering strategies.
    Chondrogenesis
    Articular cartilage repair
    Hyaline cartilage
    SOX9
    Citations (29)