ABSTRACT

 

Hyaluronic acid or hyaluronan (HA), a biopolymer composed by a chain of repeated disaccharidic units (N-acetylglycosamine and glycuronic acid, connected by glycosidic bonds), with a molecular weight (mw) ranging from tenths to thousands KDa, is more and more employed in post-surgical, orthopaedic, rheumatologic, ophthalmologic, rhinologic, dermatologic and, more recently, pneumologic.We have investigated whether two different HA preparations under the form of colloidal solutions, the first containing HA at a mw of 300 KDa, the second containing a mixture of 5 parithetic aliquots of HA with a mw of ~ 400, 800, 1.200, 1.600, 2.000 KDa, are provided with different therapeutic properties when employed by local applications b.i.d. for 10 consecutive days in adults suffering from atopic dermatitis. In two groups of 12 patients each, with demographic and clinical analogous characteristics (without any other general therapy and having suspended local treatments) the two different preparations were applied on skin lesions with analogous modalities. Besides to the different interindividual (between groups) behaviour, also intraindividual different results have been observed, since in every patients the application has been done in certain skin areas and not in others ("control areas"). The results, evaluated thank to a score from 3 (signs and symptoms of severe entity) to 0 (absent) have been inconsistent and non significant in the patients treated with 300 KDa mw HA, while it resulted highly significant (p < 0.0001) when the 5 aliquot mixture was employed. Analogous observation about a direct relationship between pm and HA efficacy (intended as poor or null efficacy of low mw and good efficacy of higher mw) were published, on the prevention of experimentally-induced bronchoconstriction in animals or in asthmatic subjects, as well as on osteoarthritic pain in humans. In conclusion, the present observation on atopic dermatitis confirm that therapeutic activity of HA is pm-dependent and that, for local use, our 5 aliquot preparation, but not one at lower mw, furnishes therapeutic results in atopic dermatitis.