Cartilage Tissue Engineering: The Role of Extracellular Matrix (ECM) and Novel Strategies

Articular cartilage is a hyaline cartilage that consists primarily of extracellular matrix with a sparse population of cells, lacking blood vessels, lymphatic vessels and nerves. The only cell type within cartilage is the chondrocyte and has a low level of metabolic activity with little or no cell division and is the responsible for maintaining in a low-turnover state the unique composition and organization of the matrix that was determined during embryonic and postnatal development. The biological and mechanical properties of articular cartilage depend on the interactions between the chondrocytes and the matrix that maintain the tissue. Chon‐ drocytes form the macromolecular framework of the tissue matrix from three classes of molecules: collagens, proteoglycans, and non-collagenous proteins and maintain the extrac‐ ellular matrix (ECM) by low-turnover replacement of certain matrix proteins [1, 2].