UC San Diego

Functional articular cartilage tissue repair continues to be an unsolved problem for orthopedic surgeons, biologists, and bioengineers alike. Recently, researchers have begun investigating the potential of human embryonic stem cells (hESCs) as a potential cell source for repair of the cartilage tissue. In this thesis, a high yield population of mesodermal progenitor cells was derived from hESCs, and induced toward the chondrogenic lineage via the traditional pellet culture method, and through encapsulation in a degradable biomaterial. The subsequent hyaline cartilage-like tissue that formed through both methods was evaluated based on histology, gene expression, and biochemical analysis. Using the pellet method, the cartilage tissue that formed had large amounts of the articular cartilage marker Collagen type II and aggrecan distributed evenly throughout. When the cells were encapsulated in diacryloyl-diaminoethanol polyethylene glycol (PEG-EADA), they were also able to successfully undergo chondrogenesis in both early and late passage based on upregulated Collagen II and Aggrecan gene expression, positive collagen II and aggrecan staining, and total collagen and GAG content confirmed via biochemical assays. The hESC-derived population of cells was thus confirmed as a viable cell source for cartilage formation due to its expansion potential through passage 6 while still maintaining chondrogenic differentiation potential when induced with chondrogenic growth medium and transforming growth factor beta-1