PBS News hour did a short story on regenerative medicine a few days ago with Miles O'Brien reporting. Tissue engineers have been able to grow tissues using stem cells from the patient and an extra cellular matrix from pig balders. The resulting replacement tissue is genetically identical to the patient so there is a very low chance of rejection. Researchers have grown muscle tissue and transplanted it with great success, and are working to replace whole organs and nerves to repair spinal cord injuries.