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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-b 2 ; #3 5 ng/mL of TGF-b 2 and 100 ng/mL of IGF-I; #4 15 ng/mL of TGF-b 2 ; #5 15 ng/mL of TGF-b 2 and 300 ng/mL of IGF-I; #6 25 ng/mL of TGF-b 2 ; #7 25 ng/mL of TGF-b 2 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-b 2 and 500 ng/mL IGF-I produced results comparable to the positive control (BMMSCs treated with 5 ng/mL TGF-b 2 ) 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. ß

We tested the in vitro feasibility of porous PCL (poly(epsilon-caprolactone)) as a scaffold for cartilage tissue engineering from mesenchymal stem cells (MSCs) and determined the effects of various surface treatments. Three porous PCL scaffold modifications were examined: (1) PCL/Pluronic F127, (2) PCL/collagen, and (3) PCL/Pluronic F127/collagen, in addition to (4) PCL-only. MSCs (5 x 10(5)) were seeded in PCL scaffolds of pore size 100-150 microm, and after 3 weeks of in vitro culture, MSC-scaffolds were investigated for gross appearance, DNA amount, glycosaminoglycan (GAG) content, chondrogenic gene expression, and histology. Grossly, the cell-scaffold complexes became harder, and were more easily manipulated with a forceps after 3 weeks of culture. The three surface-treated scaffolds had higher DNA contents than did the PCL-only scaffold, and the GAG contents in PCL/collagen and PCL/F127/collagen scaffolds were higher than those seen in the PCL-only scaffold. Real-time PCR showed that Sox-9 and COL2A1 mRNA levels were remarkably elevated in PCL/collagen and PCL/F127/collagen scaffolds versus the PCL-only scaffold. On the other hand, Col1A1 and Col10A1 mRNA levels were lower in the three modified PCL scaffolds than in the PCL-only scaffold. Histological findings generally concurred with GAG and RT-PCR findings, and demonstrated the affinity of PCL-based scaffolds for MSCs and the potentials of these scaffold to induce chondrogenic differentiation. Cells showed more differentiated appearance and more abundant extracellular matrix formation in PCL/collagen and PCL/collagen/F127 scaffolds. Our findings suggest that PCL-based porous scaffolds may be useful carriers for MSC transplantation in the cartilage tissue engineering field, and that collagen-based surface modifications further enhance the chondrogenic differentiation of MSCs.

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