Hyaluronan viscoelasticity

Intra-articular hyaluronan (lA-HA) injections are widely used to treat osteoarthritis (OA). This procedure is often referred to as viscosupplementation (22) because it involves the replacement of pathologic synovial fluid with viscoelastic hyaluro-nan-based solutions or gels. In the United States, lA-HA is specifically labeled as an intra-articular analgesic and is indicated to treat pain associated with knee OA when conservative measures and simple analgesics fail (e.g., acetaminophen). In other parts of the world, lA-HA is also approved for treatment of joints other than the knee and in some countries for arthritic conditions other than OA. The molecular basis for this application of hyaluronan, and the history of its development, has been recently reviewed (23). In this chapter, we will update the clinical evidence and describe the different types of hyaluronan formulations available in the United States. 

Balazs EA. Viscoelastic properties of hyaluronan and its therapeutic use. In Garg HG, Hales CA, eds. Chemistry and Biology of Hyaluronan. Amsterdam Elsevier, Ltd., 2004 415-455. 

Denlinger JL, Balazs EA. The fate of exogenous viscoelastic hyaluronan solutions in the primate eye. Rosen ES (ed) Viscoelastic Materials Basic Science and Clinical Applications. New York, Pergamon Press, 1989, S. 185-199... 

The major component of the synovial fluid, that is, hyaluronan, has two main functions namely lubricant and shock impulse damping [25]. Furthermore, hyaluronic acid is a major component of the extracellular matrix of the connective tissue. This kind of polymer should exhibit viscoelastic properties that directly depend on its microstructure and external parameters such as shear rate, stress and temperature. Knowledge of dependence of model synovial fluid viscosity on the shear rate, stress and temperature is very useful for biomedical applications, for example, in treatment of joint diseases. 

The vitreous body of the eye largely consists of HA produced by the cornea cells. Due to the viscoelastic properties of hyaluronan, the vitreous body assures permanent intraocular pressure and prevents detachment or retina and pigment epithelium. 

Hyaluronic acid, (HA), also referred to as hyaluronan, is an important constituent of extracellular matrix, and has been used as a viscoelastic biomaterial for medical purposes, such as injectable fillers, and in drug delivery systems. The hyaluronan-based nerve conduit is not cytotoxic and shows good... 

Weiss C, Abatangelo G, Weigel PH. Why viscoelasticity is important for the medical uses of hyalirronan and hylans. In New frontiers in medical sciences redefining hyaluronan. Amsterdam Elsevier 2000. p. 89-103. 40. 

Denlinger JL. Hyaluronan and its derivatives as viscoelastics in medicine. In Laurent TC, editor. The chemistry, biology and medical applications of hyaluronan and its derivatives. London and Miami Portland Press Ltd 1998. p. 235-41. 

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