The potency of culture-expanded nasal septum chondrocytes for tissue engineering of cartilage.

Tissue engineering techniques to create extra autologous cartilage for reconstructive surgery receive more and more scientific and industrial attention. The objective of this experimental study was to assess the use of in vitro multiplied chondrocytes of the nasal septum for generation of cartilage grafts using tissue engineering techniques. Cells isolated from a biopsy of septal cartilage of rabbits and humans were expanded in culture to get a sufficient number of cells to engineer a cartilage graft. The drawback of the expansion procedure is that the cells lose their cartilaginous phenotype (dedifferentiation). We studied a method to reverse the dedifferentiation of expanded cells to stimulate them to produce cartilage matrix of good quality. Rabbit chondrocytes showed reversion of dedifferentiation (redifferentiation) when fetal calf serum was replaced by the growth factors IGF1 and TGFbeta2. This was expressed by increased glycosaminoglycan synthesis and increased numbers of collagen type II-producing cells. The redifferentiation capacity of septal cartilage cells of young rabbits was higher than that of adult rabbits. In human chondrocytes from the nasal septum redifferentiation could also be induced by replacement of serum with IGF1 and TGFbeta2. This method, however, was less efficient than in rabbits. Chondrocytes of older patients (>40 years old) were no longer sensitive to the growth factor treatment. In conclusion, our study demonstrates a method to regain cartilage phenotype in multiplied cells of nasal septum cartilage needed for tissue engineering of new cartilage. These results are promising for this technique to generate cartilage grafts for facial plastic surgery of the nasal septum.