Serpin A1 peptides as collagen turnover modulators: a cosmeceutical approach

The term “cosmeceutical” identifies a hybrid category of topical products lying between drugs and cosmetics. These products are not tested and approved as drugs, although they may contain different active ingredients, including peptides. However, it is not very common to find scientific literature supporting the claimed benefits. In this scenario, we started an R&D project aimed at developing peptide active ingredients of proven activity for cosmeceutical use. We focused our attention on serpin A1, which is part of the serpins family, proteins endowed with anti-protease activity. Following to a preliminary report on the activity of the C-terminal portion of this protein [1], we showed that the decapeptide SA1-III is able to modulate collagen type I turnover in cultured human fibroblasts [2]. With the purpose of investigating the mechanism of action of SA1-III, we synthesized four partially overlapping tetrapeptide fragments of this peptide, which were tested in vitro on cell cultures derived from neonatal human dermal fibroblasts (NHDFs), in order to determine the concentrations of collagen type I produced in the presence of each tetrapeptide, in comparison with the basal concentration of collagen, measured in untreated fibroblasts. This analysis showed that the mechanism of action leading to increased concentration of collagen type I in cell treated with both SA1-III and its derivatives is an anti-protease action rather than a stimulation of de novo collagen synthesis [3]. This effort has led to the launch on the market of an anti-age cream (Kp1) based on an active peptide, whose proven effect is to modulate collagen turnover, by inhibiting the degradation component. The claimed activity was proven in vivo by ultrasonographic dermal protein density evaluation.