Frictional properties of articular cartilage-like tissues repaired with a mesenchymal stem cell-based tissue engineered construct

We have been developing a novel tissue engineering technique for cartilage repair using a scaffold-free tissue engineered construct (TEC) bio-synthesized from synovium-derived mesenchymal stem cells (MSCs). In the present study, the effect of TEC on the repair of chondral defect in the femoral condyle of immature and mature pigs were investigated. The permeability of TEC-treated repaired tissues was significantly higher than normal level at surface layer in immature animals, while the permeability was slightly higher than normal level at middle and deep layers in mature animals. In immature animals, the coefficient of friction of TEC-treated tissues against a glass plate was load-dependently increased, with a significantly higher value than normal level observed at a high load (280 kPa). In contrast, the coefficient of friction was load-dependently decreased in mature animals, with no significant differences from normal level observed at all loads (70, 140, and 280 kPa). It is suggested that the frictional properties of TEC-treated cartilage-like repaired tissues are recovered to normal level in mature animals, while they are unrecovered to normal level due to underdeveloped, permeable surface layer in immature animals.