Hyaluronona

Hyaluronona, also known as hyaluronic acid or hyaluronan, is a naturally occurring, linear anionic polysaccharide in the glycosaminoglycan family. It is built from repeating disaccharide units of D-glucuronic acid and N-acetyl-D-glucosamine, connected by alternating β(1→3) and β(1→4) glycosidic bonds. Unlike other GAGs, hyaluronona is non-sulfated and is not covalently attached to a core protein to form proteoglycans.

Hyaluronona is a major component of the extracellular matrix in connective tissues, skin, cartilage, synovial fluid, the vitreous humor of the eye, and various epithelial matrices. It is produced at the cell membrane by hyaluronan synthases HAS1–HAS3 and is constantly turned over through degradation by hyaluronidases as well as non-enzymatic pathways. Molecular weight can vary widely, with high molecular weight HA generally exceeding 1000 kDa and low molecular weight fragments arising from breakdown.

Functions of hyaluronona include hydration and viscoelasticity of tissues, lubrication of joints, and formation of a hydrated pericellular matrix that influences cell behavior, migration, wound healing, and inflammation. The biological effects of HA are often dependent on its size; high molecular weight HA tends to be anti-inflammatory and space-filling, while low molecular weight fragments can promote inflammatory responses and angiogenesis.

In medicine and cosmetics, hyaluronona is used in intra-articular injections for osteoarthritis, as a viscoelastic agent in ophthalmic surgery, and as a dermal filler. Safety profiles are generally favorable, but adverse events can occur, particularly with injectable products, including infection or vascular occlusion, necessitating appropriate clinical handling.