Hyaluronic acid, abbreviated HA, also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. As one of the chief components of the extracellular matrix, it contributes significantly to cell proliferation and migration and also may be involved in the progression of some malignant tumors.
Hyaluronic acid is a substance that is naturally present in the human body. It is found in the highest concentrations in fluids in the eyes and joints. The hyaluronic acid that is used as medicine is extracted from rooster combs or made by bacteria in the laboratory.
- As a major component of the extracellular matrix, hyaluronic acid has a key role in tissue regeneration, inflammation response, and angiogenesis, which are phases of skin wound repair.
- HA is abundant in the granulation tissue matrix. A variety of cell functions that are essential for tissue repair may attribute to this HA-rich network. These functions include facilitation of cell migration into the provisional wound matrix, cell proliferation, and organization of the granulation tissue matrix.
- HA provides an open hydrated matrix that facilitates cell migration, directed migration and control of related cell mechanisms are mediated via the specific cell interaction between HA and cell surface HA receptors.
- HA plays an important role in the normal epidermis. In normal skin, HA is found in relatively high concentrations in the basal layer of the epidermis where proliferating keratinocytes are found. Epidermal HA also functions as a manipulator in the process of keratinocyte proliferation, which is essential in normal epidermal function, as well as during reepithelization in tissue repair. In the wound healing process, HA is expressed in the wound margin, in the connective tissue matrix, and collocates with CD44 expression in migrating keratinocytes.
- Cataracts. Injecting hyaluronic acid into the eye is effective when used during cataract surgery by an eye surgeon.
- Swelling (inflammation) and sores inside the mouth (oral mucositis). Hyaluronic acid is effective for treating mouth sores when applied as a gel or used as a rinse.
- Aging skin. Some research shows that injecting a specific hyaluronic acid medical device into facial wrinkles can reduce wrinkles.
- Dry eye.
- Osteoarthritis. Hyaluronic acid can be injected into the joint by a healthcare provider to reduce joint pain and stiffness.
Hyaluronic acid could take by mouth, applied to the skin, or by injection.
Sodium hyaluronate is the sodium salt of hyaluronic acid, a glycosaminoglycan found in the various connective tissue of humans. Sodium hyaluronate has stronger stability and penetration ability. Because it is in salt form, sodium hyaluronate is a more stable form of hyaluronic acid.
Hyaluronic acid, sodium hyaluronate, and potassium hyaluronate function in cosmetics as skin conditioning agents at concentrations up to 2%. Hyaluronic acid is not toxic in a wide range of acute animal toxicity studies, over several species and with different exposure routes; is not immunogenic, nor is it a sensitizer in animal studies; is not a reproductive or developmental toxicant; is not genotoxic, and likely does not play a causal role in cancer metastasis. Rather, increased expression of hyaluronic acid genes may be a consequence of metastatic growth. Widespread clinical use of hyaluronic acid, has been free of significant adverse reactions and toxicity (Becker et al., 2009).