Osteoarthritis. Emerging evidence for cell interactions in the breakdown and remodeling of cartilage.

Interactions among the cells of joint components appear to contribute to the dynamic events associated with breakdown of the cartilage matrix and remodeling of the articular surface in osteoarthritis. The mediator interleukin-1 may be one of the stimuli that induce release of hydrolytic factors from synovial membrane cells and chondrocytes, which contribute to the degradation of collagen and proteoglycans in the cartilage matrix. The remodeling process is associated with chondrocyte proliferation and vascular and cellular ingrowth from subchondral bone with osteophyte formation. It is postulated that growth factors isolated from cartilage and bone may contribute to repair and remodeling of the articular end of the joint.