Human mesenchymal stem cells overexpressing therapeutic genes: from basic science to clinical applications for articular cartilage repair

Adult articular cartilage has a limited capacity for self repair. Reproduction of a native structure and functional in- tegrity in damaged cartilage remains a major problem in orthopaedic surgery. Strategies based on the implantation of genetically modified cells to sites of injury may provide workable options to treat articular cartilage lesions like those resulting from acute trauma or associated with the progression of osteoarthritis. Mesenchymal stem cells have remarkable properties that make them an attractive source of cells to treat cartilage disorders due to their self-renewal capability, stemness maintenance, and chon- drogenic differentiation potential. For these reasons, such progenitor cells might be further modified by gene transfer protocols to reinforce their potency and consequently, to enhance the healing processes in damaged tissue following transplantation in sites of cartilage injury. Here, we propose an overview of the current approaches employed for cell- and gene-based treatment of articular cartilage disorders using mesenchymal stem cells.