Chondrogenic differentiation of adipose tissue-derived mesenchymal stem cells: greater doses of growth factor are necessary.

There have been controversies regarding the chondrogenic potential of adipose tissue-derived mesenchymal stem cells (ATMSCs) compared with bone marrow-derived mesenchymal stem cells (BMMSCs). The purpose of this study was to confirm the hypothesis that chondrogenesis can be achieved from ATMSCs comparable to that from BMMSCs by using greater dose of currently known chondrogenic growth factors. Chondrogenesis was induced from ATMSCs by culturing them in pellets under the following conditions: #1 without growth factors (negative control); #2 5 ng/mL of TGF-beta2; #3 5 ng/mL of TGF-beta2 and 100 ng/mL of IGF-I; #4 15 ng/mL of TGF-beta2; #5 15 ng/mL of TGF-beta2 and 300 ng/mL of IGF-I; #6 25 ng/mL of TGF-beta2; #7 25 ng/mL of TGF-beta2 and 500 ng/mL of IGF-I. After 4 weeks of in vitro culture, the pellets were harvested for DNA quantification, analysis of the glycosaminoglycan content, reverse transcription, and real-time PCR for collagen type I (COL1A1), collagen type II (COL2A1), and Sox-9. Safranin-O and immunohistochemical staining for type II collagen also were carried out, and histological grading was performed based on the findings. A combination of 25 ng/mL TGF-beta2 and 500 ng/mL IGF-I produced results comparable to the positive control (BMMSCs treated with 5 ng/mL TGF-beta2) as demonstrated by DNA amount, GAG analysis, real-time PCR, and histological findings. Although ATMSCs have lower chondrogenic potentials than BMMSCs, chondrogenesis comparable to BMMSCs can be induced from ATMSCs using a greater dose combination of growth factors. These results lend a further support to the application of ATMSCs for cartilage tissue engineering.