Anti-pollution Skin Care: It's Real


Editor's note: Anti-pollution emerged as a popular ingredient claim during the in-cosmetics trade show in Paris this April. But such a flurry of these claims left the industry (or at least, this editor) wondering how serious a trend it would become.

Then in June 2016, the Royal College of Physicians held its Anti-aging Conference in London, which solidified the fact that anti-pollution skin care is beyond a trend: it's a real concern that's here to stay. The event focused heavily on environmental pollution and oxidative stress in skin; following is an overview from this conference, authored by Katerina Steventon, Ph.D.

Environmental Pollution

Spot formation: The scientific principles of pollution were explained by Prof. Jean Krutmann, Ph.D., from Leibniz Research Institute for Environmental Medicine (Germany). He discussed traffic-related pollution in megacities like Beijing in China, Los Angeles in the United States, and Rome and London in Europe. His research into the effect of air pollution on elderly women in Germany showed a higher occurrence of pigmented spot formation on the cheeks with increasing soot concentrations.

Collaborative projects in China reported not only exposure to particulate matter (PM), but also to nitric oxide correlated with pigmentation. These gene/environment interactions involve arylhydrocarbon receptors (AHR) activated by polyaromatic hydrocarbons (PAH). Women with high genetic risk scores developed 52% more lentigines on their cheeks compared with low risk-score participants.

Topical solutions: Topical solutions to premature skin aging induced by air pollution were introduced by Imke Meyer from Symrise (France). Meyer suggested PM is as important as UV, noting 2,500 consumers in 11 countries indicated awareness of atmospheric pollution as a primary cause of skin problems. More than 80% of consumers also believed the skin absorbs pollutants. Furthermore, consumers in Brazil, Mexico, Pakistan and India were the most sensitive to dust and dirt, and the same group (in addition to China) expressed a greater urge to act upon this by paying to protect their skin from pollution.

Again, pigment spot formation was found to increase due to PM. In relation, consumers engaged in PM surveillance by checking air quality forecasts and pollution levels. While sizes of PM10 and PM2.5 do not penetrate the skin, when incorporated with PAH, they induce ROS and alter cell functions.

Symrise developed new solutions including E/Z-2-benzylidene-5,6-dimethoxy-3,3-dimethylindan-1-one (BDDI), which temporarily binds to the AHR to block it for PAH, and a ginger extract (BIO3040) that acts as a stem cell protector and anti-inflammatory ingredient. After the mode of action was confirmed in vitro, the next steps included ex vivo studies and in-use clinical studies in a polluted megacity. (Watch for more about this work in C&T's upcoming October issue.) 

Oxidative stress: Oxidative stress and aging including the effects of environmental pollution, sunlight and diet in skin were discussed by Prof. Mark Birch-Machin from Newcastle University (UK). Starting with theories of aging that span from the Wear and Tear Theory (1882) and the Rate of Living Theory (1928), to the Free Radical Theory (1956), Birch-Machin discussed life expectancy and metabolic rate correlations.

Mitohormesis refers to low levels of reactive oxygen species (ROS) that increase lifespan, whereas high levels of ROS decrease it. UV light causes mitochondrial DNA (MtDNA) damage and with limited repair due to aging, this damage accumulates. ROS production at Complex ll, in particular, seems more important than previously thought, and age-related decreases in mitochondrial Complex ll activity have been observed in fibroblasts. MtDNA damage increases with sun exposure in human skin and with aging. Therefore, MtDNA is an excellent bio-marker of sun exposure as the shortest wavelengths of UV are most effective in damaging MtDNA. Also, fibroblasts are more sensitive than keratinocytes to UV of less than 300 nm. 

Mitochondria are a diary of cellular damage as well and another tool for evaluation of intervention results; i.e, sunscreens, lifestyle and dietary antioxidants. People respond fast or slow to dietary intervention and the effect of an antioxidant depends on the deposition in targeted tissue.

Clinical Improvement of Photo-Aged Skin

Clinical benefits: The clinical benefits of a novel active ingredient for dermal remodeling were discussed by Alain Mavon, Ph.D., of Oriflame (Sweden). He highlighted the need for anti-aging products with strong clinical proof of efficacy.

In 2015, Oriflame identified a new active ingredient, n-acetylene-l-aspartic acid, through gene arrays and a connectivity mapping process. The investigation involved two pilot, double-blind randomized, placebo-controlled studies on the expression of extracellular matrix (ECM) proteins, collagen IV and fibrillin-1 in photoaged forearm skin after 12 days of treatment.

Skin firmness measurements after 28 days (Cutometer) and 3D deformation measurements after 84 days (Dynaskin) were carried out using a skin care regimen based on the active and showed positive effects. Finally, a look at sagging showed a significant decrease in the height of the upper eyelid fold vs. a placebo after 56 days of product application.

Regulatory Landscape

The regulatory landscape and rules for advertising in the UK (Clearcast) and United States (National Advertising Division (NAD)) were also discussed by a number of experts. Jack Ferguson, Ph.D. (Skinnovation Ltd., UK), explained the rigor behind supporting breakthrough “cumulative and physiological” claims for skin care benefits, which at present exist only for the area of cumulative moisturization (since 2012) and cumulative wrinkle reduction (2015). He gave an overview of the Clearcast consultancy process to establish whether the scientific and technical data submitted by an advertiser can support the claims.

Discussing clinical trial criteria and design in detail, he drew attention to statistical versus clinical significance relevant to the consumer. The body of evidence required in supporting a breakthrough claim is large, and he described the dialog with Clearcast from concept to the creation of an advertisement with breakthrough claims.

Annie M. Ugurlayan elaborated on the self-regulated U.S. advertising system by clarifying the role of the NAD, its expertise and processes for working with a consumer/competitor challenge. She reported on numerous case studies; e.g., Neutrogena Corp., Philosophy Inc. and DERMAdoctor Inc., as well as advertising for dietary supplements.

Anti-aging Strategies: Epidermal and Dermal

Prof. Paul Matts from Procter & Gamble gave an overview of strategies for skin protection in light of evolution, and the perception of skin aging in terms of health and attractiveness. He acknowledged strategies for addressing UVA that, as monitored by MtDNA damage, indicate more harm to fibroblasts than keratinocytes and an impact on dermal tissue. He also stressed the natural balance between skin surface topography and coloration when addressing perceived aging.

The key part of his talk was dedicated to the barrier-forming properties of the stratum corneum and the sophisticated biology of corneocyte maturation. Applying metrics, Matts discussed thin parts of the stratum corneum in the eye area that are prone to dermatoses and the concept of a stratum corneum barrier reserve. He introduced one of the benefits of niacinamide for increasing the thickness of the stratum corneum, evening skin tone by reducing melanin transfer and inflammation, and then asked the scientific audience to consider how to slow down the maturation process to recover a high-quality body/environment barrier.

Finally, Mike Sherratt, Ph.D., from the Centre for Tissue Injury and Repair, Manchester University (UK) discussed the influence of age, ethnicity and region on skin mechanics. Differential susceptibility of extracellular matrix proteins to UV damage and its distribution dictates different mechanical properties in aging skin. Looking at the ECM protein synthesis and degradation, he concluded that UV-chromophore rich proteins (elastic fiber-associated proteins) are degraded by UVR preferentially, as sacrificial proteins. Most ECM proteins function as supra-molecular assemblies, and understanding micro- and nanostructure is essential.

He noted that ethnicity plays a role in differing degrees of dermal-epidermal junction convolution, collagen, elastic fiber-associated protein and elastin content, and geographical ancestry; it also has been shown to mediate skin structure and dermal composition. Different layers have different mechanical properties and epidermal stiffness has been highlighted as a factor. In young and photo-protected skin, the papillary dermis forms a compliant layer between the stiffer epidermis and pliable reticular dermis.

Clearly, a good amount of work has been carried out in relation to anti-pollution skin care. This is just a sampling. While it may be a new marketing spin, it's an (anti-)age-old concept.

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