Figure 5
From: In vivo multiphoton multiparametric 3D quantification of human skin aging on forearm and face
Multiphoton — Skin color and aging differences in melanin 3D density and z-epidermal distribution profile. Data within the global epidermis from 3 clinical trials: study I acquired with DermaInspect on ventral forearm (30–40 vs 55–65 year-old; “light” ITA vs “tan” ITA skin color groups); study II acquired with DermaInspect on ventral and dorsal forearms (18–25 vs 70–75 year-old); study III acquired with MPTflex on dorsal forearm and face temple area (18–25 vs 70–75 year-old). (a) Mosaic representation of a z-substack of 20 in vivo multiphoton images (labels 1–20) acquired every 2.346 µm from the stratum corneum to the basal layer on ventral and respectively dorsal forearm skin of an old volunteer (study II). 2PEF intensity is shown in cyan hot color and Pseudo-FLIM melanin mask pixels in purple. High 2PEF signal intensities appear in white color. (b1–b3) 3D Mean melanin density in epidermis (ED); (c1–c3) 3D Melanin density z-epidermal distribution profiles (mean 3D melanin density estimated in 10 thickness-normalized epidermal layers from 1—DEJ dermal–epidermal junction level to 10—SC stratum corneum level). The data in b2 and c2 are adapted from Pena et al. Sci. Rep. 12, 1642, 2022 (Fig. S732). The b1, b2 and b3 raw data are expressed as box plots with fences, mean and median (—). All ROIs values and their distribution (dots (
) and histogram) are shown on the right side of the boxplot. Overlapping values are highlighted in black (♦). In study I, the pink 
and green 
data points correspond to respectively women and men volunteers. The (c1–c3) data are expressed as mean ± 95% confidence intervals of the mean. The mean and median values with their errors are given in Table S2. All the statistical p-values and ES parameters are given in Table S3. Statistically significant p-values: *≤ 0.05; **≤ 0.01, ***≤ 0.001. The colored brackets indicate the ES—effect size (dark green—very strong [1.3–Inf], light green—strong [0.8–1.3] and yellow—moderate [0.5–0.8]). Only p-values associated with moderate to very strong ES are shown.
