Expression of synovial fluid and articular cartilage VIP in human osteoarthritic knee: A new indicator of disease severity?

► We investigated the VIP expression in synovial fluid and articular cartilage. ► Compared to the controls, OA patients have lower VIP concentration. ► VIP level in synovial fluid is correlated with its OD in articular cartilage. ► VIP expression is found to be negatively correlated with severity of OA.