The Chondrogenic Potential of Mesenchymal Cells and Chondrocytes from Osteoarthritic Subjects

OBJECTIVE The multipotential nature of stem or progenitor cells apparently makes them the ideal choice for any cell therapy, but this as yet remains to be proven. This study (30 subjects) was designed to compare the potential to repair articular cartilage of chondrocytes taken from different regions in osteoarthritic cartilage with that of mesenchymal stem cells prepared from bone marrow of the same subject. DESIGN Cartilage biopsies, bone marrow, and blood samples were taken from each of 30 individuals with chronic osteoarthritis (aged 62-85 years) undergoing total knee replacement. The chondrogenic potential of chondrocytes isolated from cartilage biopsies taken from different regions of osteoarthritic cartilage was compared with that of mesenchymal cells by quantitative analysis of several chondrocyte specific markers and an ex vivo cartilage differentiation assay. RESULTS Cartilage-derived articular chondrocytes are superior to bone marrow-derived cells when compared for their ex vivo chondrogenic potential. Interestingly, there was marked and significant difference in the expression of chondrocytic markers between chondrocytes derived from adjacent, visually distinct regions of the diseased cartilage. When cultured in the presence of a fibroblast growth factor 2 variant, all cell samples from both tissues showed a high degree of chondrogenic potential. CONCLUSIONS Although bone marrow-derived mesenchymal cells, when supplemented with the appropriate chondrogenic factors, are a suitable source for autologous cartilage implantation, adult chondroprogenitor cells, particularly those from moderately affected regions of the osteoarthritic joints, demonstrate superior chondrogenic potential.