Biomaterials

Biography

Biography: Mei-Ling Ho

Abstract

Regenerating the damaged articular cartilage to be a functional hyaline cartilage has been a clinically unmet need. Although several current treatment methods, micro-fracture, osteo-chondral grafting and autologous chondrocytes implantation, have been used to repair the damaged cartilage, the most concerned issue is the formation of unwanted fibrous cartilage rather than hyaline cartilage in the repaired tissue. The most difficult challenge in cartilage regeneration is that the tissue mainly possesses differentiated chondrocytes to maintain extra-cellular matrix homeostasis, which lacks of in situ and circulatory stem cells. One of the current approaches to solve this clinically unmet need is the stem cell-based tissue engineering. Adipose-derived stem cells (ADSCs) have been thought to be beneficial for use because of easy harvest, higher yield numbers and multi-potent differentiation. To make it possible for ADSCs-based articular cartilage regeneration, the most important thing to be solved is the in situ chondral-induction for ADSCs. We have conducted a series of studies to develop biomaterials that can provide the extra-cellular micro-environment, including chemical and physical cues, to optimize the ADSC chondrogenesis in the repair site of articular cartilage. We found that hyaluronan (HA) enriched micro-environment can initiate and enhance ADSC chondrogenesis via CD44 mediation. On the other hand, matrix stiffness has been indicated to direct stem cell differentiation into different tissues. We further developed the chondral-induction biomaterials by ways of adjusting chemical and physical cues. We found that the modified cross-linked HA products can be optimized by tuning the HA molecular weight and matrix stiffness. Most importantly, the cartilage regeneration effect of the newly developed HA-modified hydrogel product has been confirmed in an osteo-chondral defect rabbit model (Fig.1). The findings and biomaterial development from these studies provide the important information to persuade the possibility for the future clinical use of ADSCs-based articular cartilage regeneration.