COMP does not directly modify the expression of genes involved in cartilage homeostasis in contrast to several other cartilage matrix proteins.

Objective: We investigated whether COMP may modify cartilage metabolism and play a role as an endogenous disease aggravating factor in OA.

Materials And Methods: Full-length and momomeric COMP was recombinantly expressed in human embryonic kidney cells and purified it via affinity chromatography. Purified COMP was used to stimulate either primary human chondrocytes or cartilage explants.