Stem cell-based repair and regeneration of articular cartilage

Articular cartilage is a highly specialized tissue, that when critically injured has an extremely limited capacity for regeneration. Accordingly, a clinically acceptable treatment option without risks and recurrence is currently unavailable. Inadequately treated destructive and degenerative cartilage injuries will often develop into progressive joint degeneration or osteoarthritis. Conventional surgical treatments frequently produce fibrocartilage, which cannot support the original cartilage function and deteriorates rapidly, while other conservative therapies only offer symptomatic relief. Here, we review the current tissue engineering technology for cartilage repair and describe our efforts to develop advanced cell-based engineered constructs to replace structural and biological functions, and to facilitate the regeneration of new cartilage. To overcome the limited source of available autologous chondrocytes provide only a limited population for growth and repair, hence the utility of adult bone marrow derived mesenchymal stem cells (MSCs) have been actively investigated. Biocompatible and biodegradable scaffolds, including poly-ε-caprolactone, poly-L-lactic acid, alginate, and collagen type I, have also been evaluated for their physical maneuverability, compatibility, and structural support of mesenchymal stem cells integrated into host cartilage tissue. The combination of MSCs with biomaterial scaffolds produced hyaline cartilage-like tissue with smooth articular surfaces, biochemical compositions most like that of native cartilage, and with stronger mechanical properties. As bone marrow derived MSCs are typically extracted by rather invasive means, recent studies suggest that adipose-derived stromal cells may provide similar therapeutic benefits with isolation methods that are less invasive. Based on a growing body of evidence, future strategies should clarify the role of MSCs and perhaps consider the use of adipose-derived MSCs combined with a durable and physiologically compatible biological scaffold.