Table 5.

Recent global gene-expression microarray studies relevant to human osteoarthritis (OA)

Joint or cell type	Key findings	Refs
Knee cartilage	Diseased and nondiseased knee cartilage from the same donors demonstrates significant differences in the expression of a range of genes, including WISP1 and IGFBP3.Whether this reflects a causal role in OA or is instead a consequence of the disease was not determined	55
Trabecular bone from the iliac crest	The gene profile of iliac crest from OA patients is significantly different from the gene profile of iliac crest from younger non-OA patients and from older non-OA patients, particularly for genes coding for proteins regulating bone, implying a systemic bone phenotype related to OA	56
Knee cartilage	The gene profile of knee cartilage from patients with knee OA is significantly different from that of knee cartilage from patients without knee OA. Genes that showed differential expression included those coding for proteins involved in bone formation, in the synthesis of collagens, cytokines and growth factors	57
Hip cartilage	The gene profile of hip cartilage from patients with hip OA is significantly different to that of hip cartilage from patients without hip OA. Gene expression in OA hip cartilage demonstrates a number of pathway overlaps with that of OA knee cartilage but also a striking number of differences, implying major aetiological variability between OA at the two sites	58
Cultured fibroblasts from knee synovial tissue	Compared with fibroblasts from the synovia of healthy knees, gene expression in OA fibroblasts clustered tightly and has an expression profile significantly distinct from healthy and from rheumatoid arthritis fibroblasts	59
Cartilage and growth plate	A comparison of gene expression between the growth-plate and articular cartilage of healthy adolescent donors identified the wnt pathway and several downstream target genes as brakes on chondrocyte hypertrophy, which is a known key step in OA progression	60