Thesis Defense: Johnathan Jian Duan Ng
Sponsor: Prof. Gordana Vunjak-Novakovic
Abstract: The articular cartilage has a limited capacity to regenerate. Cartilage lesions often result in degeneration, leading to osteoarthritis. Current treatments are mostly palliative and reparative, and fail to restore cartilage function in the long term. Although a stem-cell based approach towards regenerating the articular cartilage is attractive, cartilage generated from human mesenchymal stem cells (hMSCs) often lack the function, organization and stability of the native cartilage. Thus, there is a need to develop effective methods to engineer physiologic cartilage tissues from hMSCs in vitro and assess their outcomes in vivo.
This dissertation focused on three coordinated aims: establish a simple in vivo model for studying the maturation of osteochondral tissues by showing that subcutaneous implantation in a mouse recapitulates native endochondral ossification (Aim 1), (ii) develop a robust method for engineering physiologic cartilage discs from self-assembling hMSCs (Aim 2), and (iii) improve the organization and stability of cartilage discs by implementing spatiotemporal control during induction in vitro (Aim 3). Together, the methods established in this dissertation for investigating cartilage maturation in vivo and directing hMSCs towards generating physiologic cartilage in vitro form a basis for guiding the development of new treatment modalities to treat osteochondral defects.