The skin is an organ in direct contact with various air pollutants. Air pollution causes skin damage and favors skin aging processes such as dark spots and wrinkles, through oxidative stress. In particular, air pollution causes alteration of skin barrier functions and inflammation. Skin exposed to pollutants reduces its antioxidative potential. In fact, pollutant substances, mainly particulate matter (PM10, PM2.5), accelerate skin aging through specific activation of intracellular receptors called AhRs (aryl-hydrocarbon receptors). Several studies have demonstrated that AhRs are involved in the pathophysiology of skin, including skin hyperpigmentation, photocarcinogenesis and skin inflammation.

In particular, is confirmed the influence of combined pollutants upon squalene oxidization. Squalene (C₃₀H₅₀) is, among the lipid class, a molecule highly sensitive to oxidization. This property is obviously linked to the presence of six carbon double bonds (C=C), making squalene, within lipids, the most unsaturated molecule. Abundantly found within the liver of Squales, hence the derived name, this molecule is, however, found at a very low amount in the human organs or tissues, at the exception of the sebaceous glands, where its presence within sebum (10-15%) on to the face or upper torso is specific to humans.

The oxidization of squalene brings important consequences at various levels. From a cutaneous aspect, it clearly leads to cytotoxic, pro-inflammatory, immunological events and possibly speeds up the skin ageing process. Squalene oxidization appears a reliable marker of various sources of pollution-induced skin assaults.

So, it is important to protect squalene from oxidation by topically application of anti-pollution and antioxidant products.

In vivo anti-pollution test, is an innovative test to evaluate the efficacy of anti-pollution cosmetic products evaluating the effect of pollution on squalene peroxide (SQOOH)/squalene (SQ) skin ratio by face swabs.

The test is conducted on subjects that living in a homogenous urbanized, high pollution area and that spend at least 2 hours daily outdoor.

Subjects living in high pollution area have a reduced content of SQ in sebum, increased lactic acid levels and altered cohesion of stratum corneum. The pollutant substance benzopyrene increases the skin amount of SQOOHs, and this process contributes to skin hyperpigmentation and dark spot formation.

To collect the biomarkers on the skin (the squalene peroxided), is used an appropriate kit and a sampling methods by swabs. Swab homogenates are centrifuged and subsequently analyzed for squalene monohydroperoxide (SQOOH) and SQ content with liquid chromatography system. All the measurements are performed before any application and after defined consecutive days of product use. Meanwhile, the investigational product is applied, under the normal condition of use, by test subjects at home.

During the study, are also monitored the values of the mainly particulate matter: PM10, PM2.5.

From statistical analisis of all data, collected before and after a treatment with an anti-pollution and/or antioxidant products is possible to evaluate its impact on the oxidation of squalene and therefore its efficacy.

The effectiveness of product could be confirm by clinical examination, photographic and instrumental documentation by corneometry and elastometry.

This type of study also evaluate the tolerability of the products on the skin face and allow to collect the discomfort sensations, that are reported directly by test subjects during the study.

Therefore, in vivo anti-pollution test is an innovative and adequate test to evaluate the efficacy of anti-pollution cosmetic products.

Eurofins performs efficacy and safety tests on a specific panel of test subjects representing the potential consumer of the product under strict dermatological and medical control. The products are tested on healthy test subjects simulating real conditions.

Contact our laboratories for more information.

Eurofins Cosmetics & Personal Care

Cosmetics@eurofins.com

www.eurofins.com/cosmetics/