Long-term treatment with moisturizers affects the mRNA levels of genes involved in keratinocyte differentiation and desquamation

In a recent study, we showed that long-term treatment with two different moisturizers affected TEWL in opposite directions. Therefore, we decided to examine the effect of these moisturizers on the cellular and molecular level. In a randomized controlled study on 20 volunteers, epidermal mRNA expression of genes essential for keratinocyte differentiation and desquamation after a 7-week treatment with two moisturizers was analyzed. Treatment with one test moisturizer increased gene expression of involucrin, transglutaminase 1, kallikrein 5, and kallikrein 7, while the other moisturizer affected only expression of cyclin-dependent kinase inhibitor 1A. Thus, moisturizers are able to modify the skin barrier function and change the mRNA expression of certain epidermal genes. Since the type of influence depends on the composition of the moisturizer, these should be tailored in accordance with the requirement of the barrier of each individual patient, which merits further investigations.