SKIN CARE
In vivo studies Panel pre-selection and study design The density of BaP in urban atmosphere is between 0.5 and 3 ng/m3
of 7.5 to 45 ng/day. In addition, published data show
that smokers consuming more than 10 cigarettes per day for at least 5 years absorb about 50 ng of BaP per day.7 Therefore, the volunteers selected for this in vivo study smoked more than 10 cigarettes per day (Fig. 1) and various skin parameters had previously been compared to those of non-smoking volunteers. The effect of TE formulated at 3%
in an emulsion vs. the placebo was first determined in the group of smokers (Group A – 20 volunteers, mean age 50±6 years) and in the group of non- smokers (Group B – 20 volunteers, mean age 49±7 years) (Fig. 1, study 1a and 1b). Each emulsion was applied twice a day to each half of the face for 28 days. Each analysis was conducted at the beginning (D0) and end of the test (D28). Following this, differences between the
half of the face of smokers (Group A) treated with TE and the half of the face of non-smokers (Group B) treated with the placebo (Fig. 1, study 2) were analysed.
Study of the level of oxidised proteins Samples of stratum corneum were taken with adhesive tape (D-Squames Monaderm, Cat. No. DS100). A single skin surface sample was taken at each measurement point after applying a constant pressure for five seconds. Oxidised proteins were labelled directly
on the adhesive tape after sampling the volunteer. The visualisation reactant was a solution of fluorescein-5-thiosemi- carbazide (FTZ) (Molecular Probes Cat. No. F121), a specific marker of carbonyl groups. FTZ labelling enabled the quantity of oxidised proteins on the surface of the skin to be determined. Green fluorescence
0.600 0.500 0.400 0.300 0.200 0.100 0
Significant result according to
Student’s t-test compared to: *
untreated control keratinocytes (P<0.05)
†
BaP-treated control keratinocytes (P<0.05)
0.511*
0.385 –61%
0.169
Untreated control
Control
Apolluskin +BaP
Figure 2: Effect of TE on the level of activated AhR in human keratinocytes exposed to an environmental pollutant.
78 PERSONAL CARE September 2015 0.5% 0.199† 3% TE
1a: Study of the effect of TE
, i.e. inhalation
Group A (smokers) 20 volunteers 50±6 years
Volunteers distributed
in two groups
Group A (non-smokers) 20 volunteers 49±7 years
Placebo
3% TE
1b: Study of the effect of TE
2: Study of the capacity of TE to reduce existing differences between the two groups Figure 1: Diagram of the in vivo studies of TE efficacy.
(wavelength 520 nm to 565 nm) is proportional to the quantity of oxidised proteins in the sample of stratum corneum. The fluorescence of each sample was
observed using a fluorescence microscope (Olympus IX70) equipped with a CCD camera (Nikon DXM 1200C) coupled to image analysis software (Nikon NIS- Elements). Four representative acquisitions of each sample were obtained.
Study of complexion radiance The complexion radiance of subjects was evaluated by two experts trained to assess several parameters representing the complexion. The evaluators were unaware of the treatments used by the volunteers when scoring was conducted. The evaluation used scoring scale (from 1 to 10) and the following parameters were used for this study: Transparency of the skin. As skin is finer and more transparent, more natural light passes, giving a healthy appearance.
Reflection of the skin is characteristic of a radiant complexion. The skin is more luminous as the intensity of light reflected from prominent parts of the face increases.
These parameters were determined on the following zones: Cheekbones Forehead Chin Eyes
Statistical analysis of the data Studies of distribution, variance and significance of the different investigations were conducted using the Shapiro-Wilk test, the Fisher F test, Student’s t-test and Wilcoxon’s test, respectively. The software used was Statgraphics version XV.
Results In vitro studies Study of nuclear translocation of AhR and of the expression of CYP1A1 on normal human keratinocytes In the presence of BaP, the activation of AhR (or nuclear translocation) resulting from its migration from the cytoplasm to the nucleus, significantly increases in human keratinocytes (Fig. 2, increase in the level of activated AhR between the untreated control [red] and the BaP-treated control [yellow]). In the same conditions of BaP treatment, TE tested at 1% significantly reduces this translocation by 61%.
Using the same model, the expression
of CYP1A1 is significantly increased in the presence of BaP, while TE tested at 1% significantly reduces its expression by 41%. These in vitro studies demonstrate the capacity of the active ingredient TE to regulate the AhR-CYP1A1 pathway.
Apolluskin 1.0%
In vivo studies A prior modelling study revealed significant differences in the quantity of oxidised proteins and essential parameters of the complexion radiance between the skin of smokers (polluted with BaP) and non- smokers (data not shown). Based on these results, TE was tested vs. placebo.
Placebo
Activated AhR level (AU)
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