Cartilage and bone regeneration using gene-enhanced tissue engineering

Joint cartilage injury remains a major problem in orthopaedics with more th an 500,000 cartilage repair procedures performed yearly in the United State s at a cost of hundreds of millions of dollars. No consistently reliable me ans to regenerate joint cartilage currently exists. The technologies of gen e therapy and tissue engineering were combined using a retroviral vector to stably introduce the human hone morphogenic protein-7 complementary deoxyr ibonucleic acid into periosteal-derived rabbit mesenchymal stem cells. Bone morphogenic protein-7 secreting gene modified cells subsequently were expa nded in monolayer culture, seeded onto polyglycolic acid grafts, implanted into a rabbit knee osteochondral defect model, and evaluated for bone and c artilage repair after 4, 8, and 12 weeks, The grafts containing bone morpho genic protein-7 gene modified cells consistently showed complete or near co mplete bone and articular cartilage regeneration at 8 and 12 weeks whereas the grafts from the control groups had poor repair as judged by macroscopic , histologic, and immunohistologic criteria, This is the first report of ar ticular cartilage regeneration using a combined gene therapy and tissue eng ineering approach.