Table 1.
Biological effects of HA
Effects on extracellular matrix | Effects on immune cells | Effects on inflammatory mediators |
---|---|---|
• Enhanced HA synthesis | • Inhibits proliferation and activation | • Reduced levels of |
• Enhanced synthesis of PG and chondroitin sulfate | • Reduced motility of lymphocytes and macrophages | ○ Prostaglandins |
○ Leukotrienes | ||
• Suppressed PG release from extracellular matrix | • Inhibits phagocytosis | • Increased production of cAMP |
• Suppresses aggregation of neutrophils | • Reduced expression/activity of | |
• Prevents PG breakdown from cartilage | • Inhibits adhesion and neutrophil-associated cartilage destruction | ○ IL-1, IL-6 |
• Reduced markers of cartilage breakdown (chondroitin 4- and 6-sulfates) | ○ Stromelysin | |
○ TNF-α | ||
○ TIMP-1 (inhibits MMP) | ||
○ Plasminogen activator | ||
• Reduced arachidonic acid release | ||
• Antioxidant effects | ||
• Reduced production of NO |
Abbreviations: HA, hyaluronic acid; PG, proteoglycans; cAMP, cyclic adenosine monophosphate; IL-1, interleukin-1; IL-6, interleukin-6; TNF-α, tumor necrosis factor α; TIMP-1, tissue inhibitor of metalloproteinases-1; MMP, metalloproteinase; NO, nitric oxide.