26 SKIN MICROBIOME A Day 0 Placebo Day 28 C
10% 5% 0% -5%
-10% -15%
Active ingredient
-20% -25%
S100A8/9 B
0% -5%
-10% -15%
-20% -25%
Placebo Active ingredient D
20% 10% 0%
-10% -11.2% -20.4%**
-20% -30% -40% -50%
* * #
Figure 1: Effect of the active ingredient formulated in a shampoo at 2% vs placebo on visible signs of sensitive scalps (squames, erythema, sebum). A: Representative pictures of sensitive scalp condition before and after shampoo treatments with or without the active ingredient (C-cube); B: squames evaluation (scoring): C: sebum level (Sebutape®); D: Inflammatory markers measurement (ELISA analysis of swab samples). Statistics: **: p<0.01; *: p<0.05; #: p<0.1.
signed, informed consent. 40 men and women aged between 21 and
69 years old (average age 46.3) were randomly divided into two groups: one group applied the active ingredient in a shampoo formulation and the second group applied the placebo formulation. Table 1 shows the details of the active and placebo formulations. Volunteers washed their hair two to three
times a week, depending on their usual habits, for 28 days. To assess the capacity of the active to soothe the scalp, the following parameters were studied: desquamation (with scoring), scalp erythema (pictures), sebum production (Sebutape® method) and scalp irritation level (chemical dosage of inflammatory markers IL-1RA and S100A8/9 collected by swabs). In addition, the number of aerobic bacteria from swab samples was counted after 72h cultivation and the number of yeasts/molds was counted after 5 to 7 days cultivation to evaluate the effect of the active ingredient on the scalp’s microbiota. The cultivation step ensures that only viable microorganisms are counted, as the objective was to demonstrate the active ingredient does not affect the microbiota. Then, identification of the microorganism was performed by mass spectrometry MALDI-TOF and score of flora preponderance were attributed by genre (1: minority, 2: intermediate, 3: majority). Statistics: the normal distribution of the data
was verified (Shapiro test). Once normality is validated the student t-test (paired data) was used. In case of non-normality the Wilcoxon test was performed.
PERSONAL CARE May 2021
Reduction of scalp sensitivity key markers Scratching and itching sensations are often associated with scalp sensitivity. They can lead to the apparition of dandruff, erythema and a higher sebum content.5
During the clinical
trial, the efficacy of the active ingredient was studied by assessing the improvement of the macroscopical features of sensitive scalps (squames, redness, and sebum content). We observed and quantified a significant decrease in scalp flakes (Fig 1A and B) and erythema (Fig 1A and D) on the volunteers who used the shampoo containing the active. The active ingredient reduced the squames at the scalp surface by 20.4% at day 28 compared to day 0 (Fig 1B) while the placebo showed no significant effect. In addition, we observed that the active efficiently reduced erythema and decreased the level of inflammatory markers IL-1RA and S100A8/9 while the placebo worsened scalp conditions by increasing scalp redness and increasing inflammatory markers (Fig 1A and 1D). The process of irritation starts with the
activation of certain inflammation markers such as cytokines. This activation leads to a cascade of events that in the end maintain an inflammatory status. It has been shown that IL-1Ra is a good indicator of the status of scalp health. Indeed, a high level of IL-1Ra is found in many compromised scalp conditions such as eczema, dandruff or seborrheic dermatitis.9 Another interesting marker of skin condition is the S100A8/9 protein, which can propagate inflammation and also cause a decrease in
the level of key skin barrier proteins such as filaggrin and loricrin.10
As one of the features of
a sensitive scalp is irritation, we assessed, in vivo, the level of these two biological markers IL-1Ra and S100A8/9 before and after the use of a shampoo containing the active ingredient, in comparison to a placebo shampoo. To our knowledge, this is the first time that these inflammatory markers (IL-1Ra and S100A8/A9) have been studied and quantified directly on sensitive scalps. As shown in Figure 1D, the two markers
S100A8/9 and IL-1Ra significantly decreased in the group of volunteers treated with the shampoo containing the active, compared to in the placebo group. This demonstrates the efficacy of the active ingredient in soothing sensitive scalps by limiting the production of proteins that trigger the inflammation process. In addition, we evaluated the effect of the
active ingredient on the release of histamine, another well-known biological trigger of skin itching. Histamine released from mast cells, basophils and keratinocytes11
contributes to
the propagation of the inflammation. To do so, mast cells (MC/9, ATCC,
Manassas, VA, USA) were seeded in 24-well plate. After 24h, cells were pre-treated for 2h with the active ingredient at 0.005, 0.01 and 0.02 % then the histamine inducer A23187 (500 nM) was added. After 24h, supernatants were dosed for histamine using the Histamine EIA kit (Enzo Life Sciences, Farmingdale, NY, USA) according to manufacturer’s instructions. We demonstrated that the active ingredient at 0.02%
www.personalcaremagazine.com # -20.4%* * IL-1Ra 5.9% Placebo ■ Active Ingredients ■
Squames (% vs. D0)
IL-IRa and S100A8/9 levels (% vs. D0)
Sebum level (% vs. D0)
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92
