报告一：Challenges to cartilage tissue engineering with the use of mesenchymal stem cells

报告二：Biophysical stimulation in directing stem cell chondrogenic differentiation

报告人：Zheng Yang

时 间：4月1日（周日）晚上6:40
地 点：三教104 
主持人：葛子钢（特聘研究员）

报告一内容摘要：
    The use of mesenchymal stem cell (MSC) for cartilage repair has been widely investigated. However, many challenges still remain, foremost, the technology for the regeneration of cartilage with biochemical and mechanical properties that is compatible to physiological cartilage and the recreation of the complex zonal organization of mature articular cartilage.  In order to improve the efficiency of tissue engineering approaches for articular cartilage regeneration, an important biotechnological effort would entail harnessing the molecular and physical cues in the microenvironment to achieve the desired lineage and phenotype specification for differentiated cells. This presentation will give a summary of the endeavour of NUS Tissue Engineering Program in characterising the effect of biochemical and physical cues towards stem cell chondrogenic differentiation with the aims of translating these empirical knowledge into future scaffold design for cartilage tissue engineering.

报告二内容摘要：
    Mesenchymal stem cell (MSC) derived chondrocytes has the tendency to undergo hypertrophic maturation development. However, transplantation of MSC at orthotopic sites resulted in formation of cartilage devoid of type X collagen, except in areas in close vicinity to bone, indicating that the in vivo niche and physiological mechanical force are able to provide the appropriate signaling mechanism and biomechanical cues that shape the fate of the transplanted MSC. In this study we investigated the effect of dynamic compressive loading on chondrogenesis of human MSCs laden on a chitosan modified elastomeric poly [L-lactide-co-ε-caprolactone] scaffold. MSC in the scaffold was chondrogenic initiated with a TGF? differentiation media before subjecting to dynamic compressive loading regimen via a custom-made, computed-operated bioreactor. Chondrogenic development of mechanically stimulated samples was compared to control, non-mechanically stimulated samples. Dynamic compressive loading improved the cartilaginous ECM expression and deposition, resulting in tissue of higher mechanical modulus. Compressive loading, however, reduced the hypertrophic development of MSC-derived chondrocytes. Our results suggest that mechanical loading regulate chondrogenic maturation development of MSC, and should be taken into consideration when directing stem cell differentiation for cartilage tissue engineering.