ABSTRACT
This study investigated metabolism of autologous chondrocytes after initial expansion
immediately before implantation. Chondrocytes cultured in either monolayers or alginate
beads were treated with insulin-like growth factor-1 (IGF-1), osteogenic protein-1
(OP-1), or a combination. Proteoglycan synthesis and DNA content were tested in both
cultures. Alginate beads also were analyzed with live/dead cell assay, safranin O/fast
green stain for histology, and immunohistochemistry with antibodies against collagen
type II and VI, aggrecan, decorin, and fibronectin. In monolayers, autologous chondrocytes
changed their morphologic appearance. In alginate, they maintained chondrocytic phenotype.
Growth factors, especially combined, promoted cell survival and induced chondrocyte
proliferation. OP-1 stimulated the largest cartilage-specific matrix and the most
accumulation of collagen type II and fibronectin, although the overall matrix synthesized
by autologous chondrocyte implantation cells was smaller than that produced by normal
chondrocytes. The clinical implications of this study suggest a significant promise
for anabolic growth factors in cartilage repair as a potential modifying therapy for
the enhancement of chondrocytic phenotype of autologous chondrocytes.
