Biomateriales, factores de crecimiento y células para regeneración de cartílago

Resum

Joint cartilage forms a variety of connective tissue that lines the ends of synovial joints providing a surface of low friction and distributing the load to the underlying subchondral bone. Cartilage is characterized by low cell density and absence of vascularization and inervation, which makes it very difficult to repair after injury. The lack of success of the conventional treatments applied so far has boosted in recent years the development of tissue engineering for the repair of cartilage lesions. In this work, two biocompatible systems are elaborated and tested, evaluating their chondrogenic capacity in the repair of a critical osteochondral defect in rabbit femur. The first system, a bilayered scaffold of alginate-PLGA (ALG-PLGA), containing BMP-2 (2.5 and 5 ¿g) or TGF-ß1 (50 ng) (FC) encapsulated in PLGA microspheres, controlled the release of GF, and showed a high rate of repair 12 weeks post-implantation, in all groups treated with GF. The second, bilayered system, incorporated a new segmented polyurethane (SPU) to replace the alginate, and also showed excellent control of the release of GF, and a high repair rate of the defect 12 weeks post-implantation, in all groups treated with GF. Based on several aspects, including the degradation rate of the systems, the ALG-PLGA system was selected as the most suitable, and BMP-2 at a dose of 5¿g as the most appropriate, to evaluate, in a comparative way, the chondrogenic capacity of treatment with bone marrow-derived mesenchymal stem cells (MSC) or autologous chondrocytes (rbC), alone, or in combination with BMP-2. The repair efficacy of all individual treatments or in combination was the same 12 weeks postimplantation.The global analysis of the results shows, on the one hand, that both systems are suitable for application in tissue engineering, and on the other hand, it justifies the use of GF (BMP-2 / TGF-ß1) against cell therapy in regenerative medicine of cartilage.