Pharmacological studies on elastin peptides (kappa-elastin). Blood clearance, percutaneous penetration and tissue...

Soluble elastin peptides obtained by partial hydrolysis of ligamentum nuchae elastin in 1M KOH in 80 per cent aqueous ethanol (kappa-elastin) were labelled in vitro by incubation with tritiated borohydrate. 3H-labelled kappa-elastin was administered iv and percutaneously and its elimination and organ distribution determined. iv administered kappa-elastin is rapidly eliminated through the kidneys with a first rapid phase (t 1/2 9.9 min) and a second slower phase (t 1/2 169 min). Percutaneously administered elastin peptides penetrate in the dermis and 30 to 40 per cent of the administered label can still be found in the skin 48 hours later. Resorption through the skin is a slow process, with very little or no radioactivity detectable at any time in the blood. Only liver and lung contained significant amounts of radioactivity (4 per cent and 2 per cent of the total dose administered) at 48 hours after administration. Urinary elimination represented about 5 per cent of the administered dose. Histochemical studies performed on the skin of rats treated daily with kappa-elastin (25 mg per day for 4 weeks) showed an increase of elastin-staining material in the dermis. This increase is partly due to a modified staining of collagen bundles, resulting probably from the association of elastin peptides with the collagen bundles. It may also partly be due to an increase of elastin fibers in the dermis through the stimulation of fibroblast activity. These histochemical results confirm the penetration of elastin peptides in the dermis, their association with dermal collagen fibers and also their action on the cellular activity of the dermis.