UNDERSTANDING SOLAR SKIN ELASTOSIS 179 fi rmness of the skin with a noncontact method. Dynaskin® produces a deformation close to the clinical approach by blowing air perpendicular to the area of interest or with a dedicated angle of 45°. The 3D sensor, using fringe projection techniques, captures just before the deformation of shape of the local surface and then when the deformation is applied. The parameters studied are the volume (mm3) and the maximal depth (mm) of the deformation. A decrease in these parameters shows an improvement in the fi rmness of the skin. Results and statistics. The results were expressed with the mean percentage of variation of the mean value of measured parameters: (meanDx-meanD0)/meanD0. The mean per- centages of variation compared with placebo were also calculated as mean variation of Hamamelis at 1% mean variation placebo. The normality of distribution was checked using Shapiro–Wilk test (level of signifi cance at 1%). The statistical comparisons of the evolution of the parameter with time and with the placebo have been performed with Student t-test (if the normality of distribution is confi rmed) or with the nonparametric Wilcoxon test or Mann–Whitney test (if the normality of distribution is rejected). The level of signifi cance is 5%. RESULTS TOO MUCH ELASTIN AND LACK OF LOXL1 UNDER UVA IRRADIATION IN THE DERMIS: AN INEFFICIENT BALANCE Using quantitative RT-PCR, we have shown in fi broblasts that under UVA radiation, the expression of elastin mRNA is increased by 7.5-fold, whereas the one of LOXL1 mRNA remains stable (Figure 1). This imbalance between the expression of elastin and LOXL1 suggests that elastin is not conveniently cross-linked and therefore that the amount of functional fi bers synthesized under UVA radiation is insuffi cient. Fi gure 1. Expression of LOXL1 and elastin mRNA in UVA-irradiated fi broblasts versus nonirradiated cells (0).

JOURNAL OF COSMETIC SCIENCE 180 OUR SPECIFIC HAMAMELIS EXTRACT BALANCES ELASTIN—LOXL1 EXPRESSION TO OBTAIN FUNCTIONAL ELASTIN FIBERS Results showed that our specifi c Hamamelis extract at 0.05% induces LOXL1 mRNA expression by twofold in UVA-treated fi broblasts when the specifi c Hamamelis extract was added just after UVA exposure/treatment and when the specifi c Hamamelis extract was added 24 h before UVA and just after UVA (pre- and postirradiation). Fig ure 2. Induction of LOXL1 mRNA with a specifi c Hamamelis extract at 0.05% pre- and postirradiation with UVA exposure at 7.5 J/cm2 versus irradiated control (not treated with plant extract). Figu re 3. Evaluation of elafi n in normal UVA-treated human biopsies with and without the specifi c Hamamelis extract. (A) Quantifi cation of elafi n staining in purple in the dermis. (B) Corresponding images.