Antiaging and antioxidant effects of topical autophagy activator: A randomized, placebo-controlled, double-blinded study.

Background Recently, potential roles of autophagy in skin homeostasis received many interests. But, little has been reported for the potential antiaging effects of autophagy activator. Objective With the newly synthesized autophagy activator, heptasodium hexacarboxymethyl dipeptide-12 (Aquatide (TM)) in vitro and clinical efficacy of the topical autophagy activator as an antiaging cosmeceutical ingredient was evaluated. Methods Antioxidant effect of Aquatide (TM) was evaluated by radical scavenging assay. In vitro effect was assessed by measuring the cytotoxicity of hydrogen peroxide in cultured normal human epidermal keratinocytes. Clinical evaluation was performed by a randomized, placebo-controlled, double-blinded study. Antioxidant efficacy was observed by measuring the carbonylated proteins in stratum corneum (SC) by fluorescein-5-thiosemicarbazide (FTZ) staining. Results Radical scavenging effects of Aquatide were observed with the ABTS assay, and significant reduction in hydrogen peroxide-induced cytotoxicity was observed in Aquatide (TM)-treated cells. Autophagy inhibitor treatment abrogated cytoprotective effects of Aquatide (TM). In a clinical study, statistically significant increase in skin elasticity was observed after 4 and 8 weeks. Quantitative analysis of carbonylated proteins in SC also showed significant reduction in Aquatide (TM)-treated group, which is consistent with the in vitro data. Conclusion These results suggest that autophagy plays important roles in antioxidant system and aging process in skin, and topical autophagy activators can be potential cosmeceutical ingredients for skin antiaging.