Cell-based tissue engineering strategies used in the clinical repair of articular cartilage

Abstract

One of the most important issues facing cartilage tissue engineering is the inability to move technologies into the clinic. Despite the multitude of current research in the field, it is known that 90% of new drugs that advance past animal studies fail clinical trials. The objective of this review is to provide readers with an understanding of the scientific details of tissue engineered cartilage products that have demonstrated a certain level of efficacy in humans, so that newer technologies may be developed upon this foundation. Compared to existing treatments, such as microfracture or autologous chondrocyte implantation, a tissue engineered product can potentially provide more consistent clinical results in forming hyaline repair tissue and in filling the entirety of the defect. The various tissue engineering strategies (e.g., cell expansion, scaffold material, media formulations, biomimetic stimuli, etc.) used in forming these products, as collected from published literature, company websites, and relevant patents, are critically discussed. The authors note that many details about these products remain proprietary, not all information is made public, and that advancements to the products are continuously made. Nevertheless, by understanding the design and production processes of these emerging technologies, one can gain tremendous insight into how to best use them and also how to design the next generation of tissue engineered cartilage products.

Keywords: Autologous chondrocyte implantation; Cartilage repair; Cartilage tissue engineering; Clinical cartilage products; Scaffold-free cartilage; Scaffolds for cartilage regeneration.

Figure 1

The classical tissue engineering paradigm used for the fabrication of the reviewed cartilage products. Various factors can be manipulated in each stage, as listed.

Figure 2

The reviewed products use either scaffold-free or scaffold-based approaches. For the scaffold-based products, the various types of scaffolds are listed. NeoCart^® and Bioseed^®-C may use a collagen and fibrin gel, respectively, as a cell carrier.