Effects of Growth Factors on the Quality of Ex Vivo–Generated Cartilage

TISSUE ENGINEERING, based on the use of synthetic biodegradable polymer cell delivery vehicles (scaffolds), was introduced in 1988 by Vacanti et al¹ as an alternate treatment modality for replacing missing cartilage. By virtue of the ability to maintain their original 3-dimensional shape, homopolymers of polyglycolic acid were configured into branching networks of thin fibers, coated with a solvent-based poly-L-lactic acid suspension, molded into the shape of a human ear, impregnated with a large population of bovine-derived articular chondrocytes, and implanted subcutaneously on the dorsum of athymic mice. These cell-polymer constructs reportedly generated cartilage analogues, which approximated the biochemical and biomechanical properties of articular cartilage in 6 to 12 weeks of in vivo time, respectively. Other more recent animal-based in vivo and in vitro studies using 3-dimensional cell culture paradigms^2-3 predict that tailor-made cartilage substitutes for craniofacial augmentation, joint resurfacing, and tracheal replacement are not too far from clinical realization.