Hyaluronan in synovial fluid (HA)

Hyaluronan (hyaluronic acid) is a high molecular weight, unbranched glycosaminoglycan composed of repeating disaccharide units of N-acetylglucosamine and glucuronic acid. In synovial fluid, hyaluronan is responsible for the fluid’s characteristic viscosity, elasticity, and lubricating properties, facilitating low-friction movement in synovial joints and absorbing mechanical shocks. It also acts as a molecular filter, retarding the escape of fluid from joint spaces and maintaining homeostasis. In addition to biomechanical roles, hyaluronan modulates local cellular behavior, immune cell trafficking, tissue repair, and inflammatory responses in the joint. In joint diseases such as osteoarthritis, both the concentration and molecular weight of hyaluronan are reduced, contributing to loss of joint function and increased degradation of cartilage[1][2][3][4][5].

Other names

Hyaluronic acidHASodium hyaluronate (pharmaceutical salt form)Hyaluronate

Exogenous hyaluronan acts as a lubricant and shock absorber by restoring rheological and viscoelastic properties of synovial fluid\nHyaluronan injections reduce inflammation, scavenge reactive oxygen species, and modulate immune responses within the joint\nHyaluronidase degrades hyaluronan, reducing viscosity or enabling drug/spread of other injectables