2 kDa Hyaluronic Acid Reduces Blemishes and Sagging in Human Facial Skin

Shota Ito,1 Hitoshi Kurihara,1 Keiko Kuriyama,1 Mamoru Kimura,1 Yoshihiro Tokudome2 1R&D Division, Kewpie Corporation Chofu, Tokyo, Japan; 2Laboratory of Cosmetic Sciences, Institute of Ocean Energy, Saga University, Saga, JapanCorrespondence: Yoshihiro Tokudome, Laboratory of Cosmetic Sciences, Institute of Ocean Energy, Saga University, 1, Honjyo, Saga, Saga, Japan, 840-8502, Tel +81-952-28-8963, Email [email protected]: Collagen metabolism declines in aging skin, causing wrinkles. On the other hand, external factors such as UV exposure cause damage to DNA, resulting in skin problems such as spots and sagging. Hyaluronic acid (HA) is involved in many biological processes, including collagen metabolism, wound healing, and skin barrier function. This study aimed to evaluate the effect of 2 kDa HA oligosaccharides (HA2k) on skin spots and sagging.Methods: In the human study, the effects of a HA2k lotion on spots and sagging were evaluated after 4 weeks of application to the skin. In vitro, the effects of HA2k on inflammatory cytokines, autophagy, and turnover of normal human epidermal keratinocytes (NHEK) were evaluated under two different stimulation conditions: injury with hydrogen peroxide or UVB.Results: In the human study, HA2k treatment reduced facial spots and sagging skin after 4 weeks compared to an untreated group. The percentage reduction from baseline after 4 weeks was also higher in the HA2k-treated group. In vitro, HA2k inhibited hydrogen peroxide-induced NHEK inflammation. Furthermore, HA2k inhibited UVB-induced NHEK damage and promoted LC3-II production. In unstimulated NHEK, HA2k promoted involucrin production.Conclusion: HA2k reduced facial spots and sagging. The effect is thought to be due to the promotion of autophagy and keratinocyte turnover. HA2k application is expected to improve skin condition.Keywords: hyaluronic acid, autophagy, anti-aging, human study