In vitro and in vivo efficacy of the Active Oligo Skin complex™, a new active ingredient processed from seawater, on multiple parameters of atopic skin

Abstract

Background: Different symptoms are associated with atopic skin, including dryness, pruritus and pain, and affect patients' quality of life. The environment, microbiota, epidermis, immune and nerve cells are all implicated in the pathogenesis of atopic skin. Staphylococcus aureus is the focus of particular attention. Epidermis is implicated at multiple levels: inflammatory process, barrier, control of moisture and water loss. Sensory neurons that participate in cutaneous neurogenic inflammation and pruritus are seen as a potential new target. Specific management strategies and new treatments for adults and children are needed to help in more refractory cases. As a baseline of management, guidelines recommend a treatment to moisturize the skin and maintain the skin barrier function, such as an emollient.

Objectives: To evaluate a new product in vitro and in vivo in order to validate the potential of its use in people with atopic skin or dry skin.

Methods: A specific mineral composition, Active Oligo Skin complex™, from seawater was developed and included in a balm. The effects of a solution and balm containing the complex were evaluated in vitro on the growth and biofilm formation of Staphylococcus aureus and Staphylococcus epidermidis in different skin models, and in vivo in adult and young volunteers.

Results: In vitro, the complex modulated bacterial biofilm formation and growth, decreased cytokine [interleukin (IL)-1, IL-6, IL-4] and neuropeptide (substance P) release, and increased the expression of CL1 and CL4. On volunteers with dry skin, the complex had a moisturizing effect after 1 h of application. Dryness and roughness were also reduced in young participants with atopic skin. The balm decreased erythema and pruritus after 21 days of topical application on 60 young participants. On 22 adult participants, stinging score was decreased after -application.

Conclusions: The Active Oligo Skin complex™ appears to display potent antipruritic and anti-inflammatory activities, both in vitro and in vivo.

Figure 1

Mature biofilm formed after 24 h by (a) Staphylococcus epidermidis MFP04 and (b) Staphylococcus aureus NR-51164 grown in pure cultures in the presence of the Active Oligo Skin (AOS) complex 10% or physiological water 10% (PW). Three-dimensional views of the biofilms and top views were generated by confocal laser microscopy and analysed by COMSTAT2 (www.comstat.dk) for calculation of the respective biomass, mean thickness and maximal thickness. Arrows indicate ‘mushroom-like’ structures that were particularly abundant in S. aureus biofilms exposed to the AOS complex. These structures were associated with an increase of the maximal biofilm thickness. *P < 0.05; **P < 0.01; ***P < 0.001; N = 4. Mature biofilm formed after 24 h by S. aureus NR-51164 and S. epidermidis MFP04 grown in mixed cultures in the presence of the AOS complex 10% or physiological water 10% (C-H). The mCherry-labelled S. aureus NR-51164 strain grown with (c) AOS complex or (e) PW was visualized in red at 543 nm. Biofilms formed by total bacteria (i.e. S. aureus and S. epidermidis) exposed to (d) AOS complex or (f) PW were visualized in green at 488 nm after labelling with Syto9. COMSTAT2 was used for calculation of the biofilms (g) biomass and (h) mean thickness. The biomass formed by S. epidermidis MFP04 was calculated by subtraction of the S. aureus biomass in the total mixed biofilm biomass. *P < 0.05; **P < 0.01; ***P < 0.001; N > 3.ns, non significant (P > 0.05).

Figure 2

In vitro inflammation model. Active Oligo Skin (AOS) complex was evaluated in different inflammatory models. (a) After 9 days of culture, reinnervated skin explant was exposed to lactic acid (LA) at 10% and complex in balm, in 4% methyl cellulose gel or respective control (PW NaCl gel or balm without complex). Graph represents mean (SEM) of interleukin (IL)-4 fold-change release compared with the control normalized at 1 for each independent experiment (Kruskal–Wallis post-hoc Dunn, *P < 0.05, **P < 0.01; N > 4). (b) Noninnervated skin explants were treated, before the addition of PMA, for 24 h with complex at 0%, 2%, 10% or 50%, or control without formula. Graphs represent the mean (SEM) of IL-1, IL-6 and tumour necrosis factor (TNF)-α release of three independent skin explants from one donor (n = 3). (c) Substance P (SP) release evaluation in a co-culture between dorsal root ganglia cells, including sensory neurones and keratinocytes, after the addition of capsaicin at 10 µg mL–1 for 15 min with or without complex at 50% or 100%. Graphs represent mean (SEM) of the percentage of SP release compared with control induction with capsaicin alone at 100% in independent experiments experiment (Kruskal–Wallis post-hoc Dunn, *P < 0.05; **P < 0.01; N = 6). Analysis of effect of AOS complex on junction expression on skin explant. Non-reinnervated skin explants were pretreated with complex in (d) 4% methyl cellulose gel or (e) in balm with their respective control 2 days before the end of culture for 7 days. Graphs represent mean (SEM) fold change obtained by the quantitative polymerase chain reaction ΔΔct method for independent experiments (Mann–Whitney, one-sided, *P < 0.05; N = 3). CL1, Claudin-1; CL4, Claudin-4; Ctrl, control; NT, nontreated; PMA, phorbol 12-myristate 13-acetate; PW, physiological water; ZO1, Zonula Occludens-1.

Figure 3

Effect of Active Oligo Skin (AOS) complex on stinging test score on women volunteers with hypersensitivity of the skin. The score was noted after 30 s, 5 min and 15 min of exposition with (a) 50% complex solution (T), (b) 100% complex solution and compared with nontreated skin (NT) after lactic acid application at 10%. The results were expressed by reporting the self-evaluation score on a scale of 0 to 3, where 3 is the maximal sting experienced. Graphs represent the mean (SEM) of each individual score for each volunteer (Wilcoxon test, ****P < 0.0001; N = 22). Evaluation of AOS complex on pruritus on pooled data from 33 participants aged 6 months to 3 years and from 33 participants aged 3 to 17 years declared by their parents as having atopic skin. Seven participants were excluded from the study. The complex was applied every day for 21 days, followed by 2 days without application. Pruritus score (c) as noted on day (D) 0, D21 and D23. Results are expressed by reporting the score from dermatologist on a scale of 0 to 10, where 10 is the maximal score. Graphs represent the mean (SEM) of each individual score for each participant (Wilcoxon test, *P < 0.05; ***P < 0.001; ****P < 0.0001; N = 59). mn, minute; ns, not significant.

Figure 4

Evaluation of Active Oligo Skin (AOS) complex™ on dryness, erythema, roughness and quality of life (QoL) on pooled data from 33 participants aged 6 months to 3 years and 33 particpants aged 3 to 17 years declared by their parents as having atopic skin. Seven participants were excluded from the study. The complex was applied every day for 21 days, followed by 2 days without application. Scores for (a) dryness, (b) erythema, (c) roughness and (d) QoL were assessed with the help of the parents, with a maximum score of 45. Graphs represent the mean (SEM) of each individual score for each participant (Wilcoxon test, *P < 0.05; **P < 0.01; ****P < 0.0001; N = 59). Effect of AOS complex™ on skin moisture was evaluated by corneometry on women participants. The results were expressed as percentage of variation compared with the beginning of the measurement (T0) and nontreated zone (e) at 3 min, 2 h, 4 and 8 h after exposure to the complex at 50%, (f) at 1 h, 4 h and 8 h after exposure to the complex at 100%, or (g) at 6 h, 8 h and 24 h with balm. Graphs represent the mean (SEM) of measure score for each participant (one-way ANOVA post-hoc Dunnett’s, *P < 0.05; **P < 0.01; ****P < 0.0001; N = 11). ns, not significant.