Genetically engineered stem cell-based strategies for articular cartilage regeneration.

Cartilage is frequently injured, often as a result of inflammatory rheumatic diseases or sports-related trauma. Given its nonvascular nature, articular cartilage has a limited capability for self-repair and currently the few therapeutic options still have uncertain long-term outcomes. Cell-based surgical therapies using autologous chondrocytes to repair cartilage injury have been used in the clinic for over a decade, but this approach has shown mixed results mainly due to the low number of harvested chondrocytes and the loss of cartilage-related phenotype and functionality after several passages of in vitro culture. A wide range of cell sources have been tested to circumvent chondrocyte limitations in cartilage repair, and stem cells have been presented as those that offer the greatest potential for clinical application. This review will focus on recent advances in stem cell-based strategies for articular cartilage repair, specifically focusing on the use of genetically engineered adult stem cells by conventional gene delivery methods and by gene-activated matrices. Perspectives in cartilage engineering are also addressed.