Eberlin S, Polettini AJ, Costa A, Pereira AFC, Weisz LTM, Lage R.
Numerous biochemical reactions take place during the transition from basal layer to the stratum corneum (SC), including the synthesis of specific basal (K5 and K14) and suprabasal (K1 and K10) keratins and cornified envelope-associated proteins in the keratinocytes. Epidermal differentiation complex (EDC) is constituted through cross-linking of involucrin, envoplakin, loricrin, profilaggrin, among others, on intracellular surface of plasma membrane in upper spinous and granular layers of epidermis. Studies have shown that variation in EDC results in the pathogenesis of at least three common skin disorders, ichthyosis vulgaris (IC), atopic dermatitis (AD) and psoriasis. In this study, we evaluated the effects of moisturizing lotions and antiperspirants on the production of envelope proteins filagrin, involucrin and loricrin, and keratins 10 and 14, using an in vitro model of human keratinocytes. The test products, including antiperspirant 1 (At-1), antiperspirant 2 (At-2), lotion 1 (Lo-1) and lotion 2 (Lo-2) were composed of different compounds from vegetable origin. Incubation of keratinocytes cultures with Lo-1, Lo-2, At-1 and At-2 promoted significant increases in the synthesis of envelope proteins filaggrin, involucrin and loricrin. Considering that more pronounced biological effects were elicited by Lo-2 treatment, which significantly increased the levels of all envelope proteins, we also evaluate its ability to stimulate the production of basal (K14) and suprabasal (K10) keratins. A sharp rise in the production of keratin 10 were elicited by Lo-2 reaching up to 2.4-fold in relation to control group. As the same way, Lo-2 also provides increase up to 54% in the synthesis of keratin 14. The water content of the SC and skin surface lipids are important factors in the appearance and function of skin barrier. Traditional moisturizing ingredients are known to decelerate the loss of skin humidity, increase hydration of the SC and improve physical and chemical properties of skin surface, making it moist, smooth and soft. However, most of the products claimed for skin moisturizing produce an immediate and transient effect, not enough to relieve the discomfort caused by eczema. Thus, optimized skin care cosmetics should be developed to supply a proper moisturizing effect and the same time being capable to balance the synthesis of skin barrier proteins. In this study, we evaluated the ability of moisturizing cosmetics in the production of proteins involved in SC turnover and integrity. Moisturizing lotions and antiperspirants increased the levels of all proteins evaluated. The results indicate a biological activity of these skin care products in the promotion of cellular hydration and skin barrier integrity.