Nonviral in vivo gene therapy for tissue engineering of articular cartilage and tendon repair

Heretofore, nonviral methods have been used primarily for in vitro transfec tion of cultured cell lines. These methods were substantially less efficien t when compared with the use of viruses, particularly when used in vivo. He rein a three-step, highly efficient method of nonviral gene delivery is pre sented, Using this method, genes have been delivered successfully into tiss ues of orthopaedic importance with high-efficiency by nonviral means. Trans forming growth factor-beta 1, parathyroid hormone related protein, and a ma rker gene were transfected into primary perichondrium and cartilage cells w ith efficiencies in excess of 70%, They overexpressed their cognate gene pr oducts showing efficacy of expression in a rabbit model of osteochondral de fect repair. Using the same method, a marker gene was delivered into a cani ne model for intrasynovial flexor tendon injury and repair, This was achiev ed by direct gene delivery during surgery. An estimated 5 additional minute s were required during surgery to complete the transfection steps. High eff iciency gene delivery was achieved in the flexor tendons, tendon sheaths, t endon pulleys, surrounding tissues, and skin. The efficiency of transfectio n approached 100% in the exposed superficial tissue layers and transfected cells were found several layers below the exposed tissue surfaces. The data show the potential of direct nonviral gene therapy in orthopaedics for ex vivo and in vivo applications.