Gene expression profiles from joint-matched macroscopically intact and OA affected cartilage of patients undergoing joint replacement surgery due to end-stage OA

Genome wide gene expression was determined in paired samples of OA affected and preserved cartilage of the same joint using microarray analysis for 33 patients of the RAAK-study. Among the 1717 genes that were significantly different expressed between OA affected and preserved cartilage we found significant enrichment for genes involved in skeletal development (e.g. TNFRSF11B and FRZB). Also several inflammatory genes such as CD55, PTGES and TNFAIP6, previously identified in within-joint analyses as well as in analyses comparing preserved cartilage from OA affected joints versus healthy cartilage were among the top genes. A notable new gene was NGF, highly up-regulated in OA cartilage. To identify gene expression profiles associated with OA processes in articular cartilage and determine pathways responsive to the disease process gene expression profiles of paired preserved and OA affected cartilage samples of the same joint were determined.