Fig. 2.

Autologous protein solution (APS) contains a number of anti-inflammatory cytokines including IL-1 receptor antagonist (IL-1ra) and soluble receptors I and II against TNFα (sTNF-RI, and sTNF-RII), IL-1ra blocks the action of IL-1β by preferentially binding to the receptor on chondrocytes while sTNF-R1 and sTNF-RII bind directly to TNFα. Via these mechanisms, APS inhibits production of matrix metalloproteinases and thus prevents progression of osteoarthritis.

Note. IL, interleukin; TNF, tumour necrosis factor; MMP, matrix metalloproteinases.