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Cartilage Tissue Engineering - Dinesh - 07-08-2006 Hello fellow biomaterial workers, I am current carrying out some preliminary work on the development of <b>cartilage replacements</b>. Many people will be aware that the cartilage tissues have very limited self-regeneration capacity. Also, the scar tissue is usually formed of a fibrous material with poor mechanical properties. For this reason, the main treatment at the moment is surgical prosthesis. However, that may well change if tissue engineering allows cartilage to repair itself. Tissue engineering is one new and exciting approach to achieving cartilage regeneration. The approach involves the use of biodegradable polymeric matrixes and isolated chondrocytes from tissue biopsies. Cells are seeded inside the biocompatible matrix and then they are implanted into the damaged joint. A large number of non-degradable and degradable polymer materials have been tested for this tissue engineering application. There was a review paper done that might interest a few of you: <!--quoteo-->QUOTE<!--quotec-->B.L. Seal, T.C. Otero, A. Panitch, <b>Polymeric biomaterials for tissue and organ regeneration</b>, Materials Science Reports R34 (2001) 147–230.<!--QuoteEnd--><!--QuoteEEnd--> Several studies have been done with synthetic degradable polymers, such as polyesters (polylactic acid (PLA), polyglycolic acid (PGA), and their copolymers), polyethylene oxide or injectable polymers like poly(ethylene glycol). Natural polymers have also been used with some success to design tissue matrixes (e.g. collagen, fibrin, gelatine, hyaluronic acid, agarose, alginate, or chitosan). Yours, Dinesh Cartilage Tissue Engineering - blake - 07-08-2006 Hi Dinesh, This article might interest you: <!--quoteo-->QUOTE<!--quotec--> <b>Advancing cartilage tissue engineering: the application of stem cell technology</b> by Joanne Raghunath, Henryk J Salacinski, Kevin M Sales, Peter E Butler and Alexander M Seifalian ABSTRACT: The treatment of cartilage pathology and trauma face the challenges of poor regenerative potential and inferior repair. Nevertheless, recent advances in tissue engineering indicate that adult stem cells could provide a source of chondrocytes for tissue engineering that the isolation of mature chondrocytes has failed to achieve. Various adjuncts to their propagation and differentiation have been explored, such as biomaterials, bioreactors and growth hormones. To date, all tissue engineered cartilage has been significantly mechanically inferior to its natural counterparts and further problems in vivo relate to poor integration and deterioration of tissue quality over time. However, adult stem cells — with their high rate of proliferation and ease of isolation — are expected to greatly further the development and usefulness of tissue engineered cartilage. INTRO: Introduction Cartilage is important in joints (hyaline or articular cartilage) and for structural features (elastic cartilage), such as the nasal septum. It has a poor regenerative capacity and its replacement tissue, fibrocartilage, is mechanically inferior. Chondrocytes are highly specialized cells that secrete the extracellular matrix proteins. The extracellular matrix of healthy hyaline cartilage consists of collagen II ( 90–95%) with lesser amounts of collagen types VI, IX, X and XI and proteoglycans. Fibrocartilage possesses higher amounts of collagen type I. The mainstay treatment for articular cartilage reconstruction is arthrodesis (joint fusion) and arthroplasty (joint replacement), although various approaches to encourage cartilage regeneration have been attempted [1,2]. Current synthetic implants have a number of drawbacks, principally infection, rejection, longevity and unsatisfactory scarring. Despite recent advances in tissue engineering the vascularisation of tissue remains problematic [3]. The low degree of vascularisation in cartilage, however, makes it an ideal target for tissue engineering. Chondrocytes are difficult to isolate in humans, replicate slowly and are prone to phenotypic dedifferentiation in culture [4,5]. This can be further affected by donor age and health status [6,7]. In view of this, tissue engineering based on these cells is unlikely to prove successful and instead studies have focused on the use of stem cells for tissue engineering cartilage (Figure 1). In this review, we highlight the potential of adult stem cells (ASCs) for tissue engineering cartilage and go on to discuss the most successful biomaterials to exploit these cells. <!--QuoteEnd--><!--QuoteEEnd--> (Current Opinion in Biotechnology 2005, 16:503–509) http://www.current-opinion.com Cartilage Tissue Engineering - blake - 07-08-2006 Here is another related article that I came across today: <!--quoteo-->QUOTE<!--quotec--> <b>Same scaffold, different cells</b> BIOMATERIALS Researchers at the US National Institutes of Health and Thomas Jefferson University have generated adipose, cartilage, and bone cells in vitro on a polymer nanofiber scaffold seeded with stem cells [Li et al., Biomaterials (2005) 26 (25), 5158]. Cells grown on a biodegradable scaffold can be used to help repair damaged tissues in the body. Stem cells could prove useful because they can differentiate into a variety of specialized cell types. Ideally, a single biomaterial scaffold should support multiple cell types, so mimicking natural tissues. The team immersed human mesenchymal stem cells in an electrospun poly(ε-caprolactone), or PCL, scaffold and induced the cells to differentiate into different cell lineages. “The electrospun nanofiberous scaffold… can be considered as a candidate biomaterial scaffold for the fabrication of a single-unitbased, multicomponent tissue construct,” says Wan-Ju Li. The scaffold is effective because its 700 nm diameter fibers imitate the collagen fibrils that support cells in the body. The fine fibers also provide a desirable degradation rate. “Unlike many other biomaterials that have been tested as scaffolds, PCL dissolves slowly,” explains lead author Rocky S. Tuan. “Some materials, like poly-D,L-lacic-co-glycolic acid, will disappear after only a few days.” “We have begun testing [the tissueengineered constructs] in vivo and have had preliminary success,” he adds. <b>“The goal is to create cartilage, but that is still about five years down the road.”</b> Tissue patches like these could alleviate pain, while more applications will be seen in the coming years, he believes. Patrick Cain <!--QuoteEnd--><!--QuoteEEnd--> Source: Materials Today - May 2005 page 13 They are hoping to create cartilage too (see highlighted text above). regards, blake