Hyaluronan
Hyaluronan is the accepted scientific nomenclature for hyaluronic acid (HA) and physiological salts of hyaluronate, the conjugate base of hyaluronic acid. Hyaluronan is classified as a glycosaminoglycan (GAG), a long, unbranched polysaccharide made of repeating disaccharides of glucuronic acid and glucosamine (Fraser, 1997). The polymer chain of hyaluronan ranges in molecular weight from hundreds of units (or Daltons) up to several million.
Hyaluronan is found ubiquitously throughout the mammalian body. It is either directly or indirectly involved in every physiological function of the body. It is found in dense concentrations in cartilage, synovial fluid, skin, vertebral discs, bones, urinary tract, cardiac valves, eyes, and various other soft tissue. Hyaluronan is most abundant during embryogenesis and declines in overall quantity and quality throughout life (McDonald, 2002).
Canonically, hyaluronan is recognized for its role in the maintenance of joint health. It is the presence of hyaluronan that makes cartilage strong enough to handle compressive forces within the joint (Seog, 2002). Hyaluronan is also found in the synovial fluid, where it provides the major source of lubrication that allows for smooth fluid movements in joints (Sabaratnam, 2005). Within bone itself, the presence of hyaluronan is primarily linked to its roles in bone modeling and remodeling processes.
Hyaluronan makes up a large part of the vitreous humor of the eye where it provides ocular moisturization and lubrication.
Hyaluronan has established itself as a protectant by its ability to confer defense to gut mucosal tissue. A recent study aimed to evaluate the effects of hyaluronan on gastric mucosa (Al-Bayaty 2011). Laboratory findings revealed that a high-molecular-weight hyaluronan-containing gel significantly protected the gastric mucosa.
Oral viscosupplementation of hyaluronan is preferential to injectable products because it eliminates the risk of adverse reactions, is more convenient, and more cost effective (Spirito, 2011).
Oral hyaluronan has been shown to be absorbed and effective (Ma, 2008). Recent clinical studies are consistent with these laboratory findings (Lukens, 2005; Kiburz, 2006). Studies with labeled, high-molecular-weight hyaluronan administered orally show distribution to the joints in as little as four hours post-administration (Balough, 2008).
Clearly, there is the potential for benefit from hyaluronan treatment as exogenous hyaluronan administration and supplementation has been shown to be safe and effective.
To be compared to the CSG family of products, any oral hyaluronan supplement must be bioavailable, absorbed, and effective. Hyaluronan must be completely hydrated in order to be bioavailable and absorbed. Once absorbed it must have the appropriate molecular characteristics to be effective.