Functions of hyaluronan in wound repair

Hyaluronan is a major carbohydrate component of the extracellular matrix an d can be found in skin, joints, eyes and most other organs and tissues. It has a simple, repeated disaccharide linear copolymer structure that is comp letely conserved throughout a large span of the evolutionary tree, indicati ng a fundamental biological importance. Amongst extracellular matrix molecu les, it has unique hygroscopic, rheological and viscoelastic properties. Hy aluronan binds to many other extracellular matrix molecules, binds specific ally to cell bodies through cell surface receptors, and has a unique mode o f synthesis in which the molecule is extruded immediately into the extracel lular space upon formation. Through its complex interactions with matrix co mponents and cells, hyaluronan has multifaceted roles in biology utilizing both its physicochemical and biological properties. These biological roles range from a purely structural function in the extracellular matrix to deve lopmental regulation through effects of cellular behavior via control of th e tissue macro- and microenvironments, as well as through direct receptor m ediated effects on gene expression. Hyaluronan is also thought to have impo rtant biological roles in skin wound healing, by virtue of its presence in high amounts in skin. Hyaluronan content in skin is further elevated transi ently in granulation tissue during the wound healing process. In this revie w, the general physicochemical and biological properties of hyaluronan, and how these properties may be utilized in the various processes of wound hea ling: inflammation, granulation and reepithelization, are presented.