Poster 1: Cell and Tissue Studies

5

Passaged Zonal Chondrocytes Can Regain Cartilage Zone-Specific Properties After Redifferentiation

Thomas Manzoni, Justin Parreno

University of Delaware

Mechanical competence of bioengineered cartilage depends on its matrix composition, which must contain collagen-2 (COL2) and aggrecan (ACAN). The biomechanical properties in native cartilage depend on the zonal architecture consisting of the superficial zone (SZ), middle zone (MZ), and deep zone (DZ). The SZ cells (SZC) produce proteoglycan-4 (PRG4) for surface lubrication, while DZ cells (DZC) produce collagen-10 (COLX) for compressive strength. Monolayer expansion to increase cell number causes loss of chondrogenic expression. We test the hypothesis that both SZC and DZC can form bioengineered cartilage rich in COL2 and ACAN, while only SZC will express PRG4, and only DZC will express COLX. SZC and DZC were isolated from bovine joints, and separately expanded. Monolayer expansion decreased chondrogenic and zonal expression in expanded SZC and DZC, while dedifferentiated molecule collagen-1 expression increased. Passaged cells were then seeded in 3D culture to allow for redifferentiation. After redifferentiation both subpopulations increased expression of COL2 and ACAN, while only DZC expressed COLX, and only SZC expressed and secreted PRG4. Zonal properties are regained by the original zonal cell subpopulation after redifferentiation. Therefore, bioengineering of cartilage rich in COL2 and ACAN, with expression of PRG4 and COLX must contain both SZC and DZC.

Research Area: Cartilage