HYALURONAN (HYALURONIC-ACID) IN HUMAN SALIVA

Hyaluronan (hyaluronic acid) is a glycosaminoglycan that functions as a constituent of ground substance, a mediator of cell proliferation an d wound healing, and that plays a prominent part in tumorigenesis as w ell as in embryogenesis. Its presence and possible role in saliva has been subjected to little study. Unstimulated and stimulated pure parot id and mixed saliva was obtained from 10 volunteers. The protein conte nt of the samples was assayed and the hyaluronan concentration was eva luated by means of an enzyme immunosorbent-like assay using a hyaluron an-binding peptide. Stimulated whole saliva had the highest protein co ntent (mean 1.26 mg/ml) followed by unstimulated parotid saliva (1.15 mg/ml), stimulated parotid saliva (0.95 mg/ml) and unstimulated whole saliva (0.93 mg/ml). Absolute hyaluronan concentrations were highest i n unstimulated whole saliva (mean 459.2 ng (nanograms)/ml), and lowest in stimulated parotid saliva (82.7 ng/ml). When hyaluronan concentrat ions are expressed as ng/mg of protein, the highest are in the unstimu lated whole saliva (mean 477.5 ng/mg protein) followed by stimulated p arotid saliva (229.7 ng/mg), unstimulated parotid saliva (179.6 ng/mg) and stimulated whole saliva (159.9 ng/mg). There are wide variations in the levels of hyaluronan in human saliva depending on the type of s aliva and the conditions at the time of collection. Regulation of hyal uronan metabolism represents an intricate balance between production a nd degradation, and it is unclear whether elevated concentrations of h yaluronan in response to tissue proliferation, regeneration or repair. The hyaluronan may contribute to the healing properties of saliva, as sisting in protecting the oral mucosa and adding to the lubricating pr operties of saliva. Copyright (C) 1996 Published by Elsevier Science L td.