In addition to the above several inflammatory cytokines, leptin also promoted the expression of other cartilage decomposition factors, such as IL8, MMP2, cathepsinD, and so on.[34] What is more, leptin mediated a dose-dependent expression of VCAM in the synovium in RA and OA cartilage cells and mice ATDC-5 cells. This evidence concerns the gene CTSD and rheumatoid arthritis.