Gene expression of alginate-embedded chondrocyte subpopulations and their response to exogenous IGF-1 delivery.

The delivery of growth factors to aid in cartilage engineering has received considerable attention. However, phenotypical differences between chondrocyte cell populations and their distinct responses to growth factors are not fully understood. To address this issue, we have investigated the gene expression of chondrocytes isolated from the superficial, middle, and deep zones of bovine articular cartilage. A three-dimensional (3D) alginate bead model was used to encapsulate zonal chondrocytes and culture with or without exogenous insulin-like growth factor-1(IFG-1) delivery. Following culture, mRNA expression of type I collagen, type II collagen, aggregan, IGF-1 and IGF-1 binding protein (IGF-BP3) were analysed at 1, 4 and 8 days. To the best of our knowledge, this is the first study to investigate gene expression of IGF-1 and IGF-BP3 by zone, and among the first studies to investigate growth factor delivery to chondrocytes in a 3D culture environment. Histological images and cell count data confirm the isolation of chondrocyte subpopulations, and gene expression data show distinct profiles for each zone, both with and without IGF-1 delivery. The data also show similar gene expression for the middle and deep zone cells, while the superficial zone group displays unique activity. Deep zone cells appear the most robust in their phenotype retention and most responsive to IGF-1 delivery. The results highlight differences in metabolic activity and varying responses to delivered growth factors between zonal chondrocyte populations.

Coates E ，Fisher JP 《-》

Gene expression of single articular chondrocytes.

Eleswarapu SV ，Leipzig ND ，Athanasiou KA 《CELL AND TISSUE RESEARCH》

Addition of hyaluronic acid to alginate embedded chondrocytes interferes with insulin-like growth factor-1 signaling in vitro and in vivo.

Yoon DM ，Curtiss S ，Reddi AH ，Fisher JP ... -  《-》

Effects of exogenous IGF-1 delivery on the early expression of IGF-1 signaling molecules by alginate embedded chondrocytes.

Yoon DM ，Fisher JP 《-》

Development and characterization of a human articular cartilage-derived chondrocyte cell line that retains chondrocyte phenotype.

Hoffman BE ，Newman-Tarr TM ，Gibbard A ，Wang S ，Hanning C ，Pratta MA ，Boyle RJ ，Kumar S ，Majumdar MK ... -  《-》