Hialuronidasas

Hialuronidasas, or hyaluronidases, are enzymes that catalyze the degradation of hyaluronic acid, a major glycosaminoglycan component of the extracellular matrix. By cleaving the long hyaluronan chains, these enzymes reduce tissue viscosity and increase permeability, facilitating the diffusion of fluids, drugs, and enzymes through connective tissues.

In humans, several hyaluronidases have been identified, including HYAL1, HYAL2, HYAL3, HYAL4, and the SPAM1 (PH20) enzyme. These isoenzymes differ in cellular localization, substrate preference, and pH optima. Bacterial and fungal hyaluronidases also exist and often function as virulence factors that promote spread by degrading host connective tissue. Hyaluronidases can act as endo- or exo-acting enzymes, generating smaller hyaluronan fragments from high molecular weight substrates.

Physiologically, hyaluronidasas participate in tissue remodeling during development, wound healing, and reproductive processes (for example, sperm hyaluronidase activity helps penetrate the cumulus oophorus). They also contribute to ECM turnover and can influence cell signaling by altering the local extracellular environment. Dysregulation of hyaluronidase activity has been associated with certain diseases, including inflammatory conditions and some cancers, where altered hyaluronan metabolism affects tissue architecture and cell behavior.

Clinically and biotechnologically, hyaluronidases are used as spreading factors to enhance the diffusion of locally injected drugs and fluids in medical procedures. They are also employed to dissolve unwanted hyaluronic acid-based dermal fillers. Safety considerations include the potential for allergic reactions or unwanted diffusion effects, with enzyme sources and formulations varying across products.