Chondrogenitor cells and gene therapy

The development of isolation and culture techniques for mesenchymal progeni tor cells from various tissues has promoted interest in the use of these ce lls for repair and regeneration of musculoskeletal tissues. The chondrogeni c differentiation of these pluripotential cells seems to be mediated by num erous cytokines most of which belong to the transforming growth factor-beta superfamily, Strategies to repair articular cartilage have focused on deli very of these cytokines or progenitor cells to the area of damage, More rec ently, with the development of gene transfer techniques, these cells have b ecome the target of in vivo gene therapy, which involves direct injection o f viral and nonviral vectors carrying transgenes. Furthermore, they are vie wed as potential carriers of the transgenes for ex vivo gene therapy, in wh ich the gene transfer is done in vitro with culture-expanded cells that the n are implanted or injected, In vitro data suggest that the chondrogenic po tential of these cells is maintained with virally mediated ex vivo gene tra nsfer. By transducing these cells with chondroinductive factors, the bioact ive factors and the target cells are delivered to the repair site.