Vichy Exposome Grant

The SALIA cohort was set up over 30 years ago to investigate the effects of air pollution on lung function, inflammation and ageing in women. There were two study populations, one from rural areas and the other from the highly industrialized Ruhr area of Germany.

A wide range of baseline health measurements were established, with questionnaires on lifestyle factors and skin factors. In 2006, with air pollution declining, the women were assessed again with about 800 having detailed examinations that included an intensive skin ageing assessment using the well-established SCINEXA skin ageing scoring system.

Extensive data sets exist on air pollutants in the Ruhr area. Land use and traffic information sets have been used as proxies for exposure to near road pollutants and the German weather service is able to provide data on direct solar radiation and diffuse sky radiation closest to the residential address.

The 2016 Vichy Exposome Grant was used by the team, with the help of a statistician, to prepare the data sets and then re-analyse it, in order to compare the interacting effects of pollution on skin ageing.

The implications of the results of this research may be multiple. They may contribute to the understanding of the physiology of the skin and its maintenance.

Firstly, if short chain fatty-acids (SCFA) are responsible for the maintenance of the homeostasis of the skin, it then remains to be determined whether the composition of SCFA is altered under various inflammatory conditions and whether this is associated with an alteration of the composition of the commensal microbiome. Secondly, if SCFA are potent modulators of skin Regulatory T cells (Treg), they may be utilized for the therapy of inflammatory skin conditions.

It is superfluous to say that SCFA are natural substances which lack toxicity and thus may gain broad acceptance, even as ingredients in cosmetics with the ultimate aim to avoid skin irritations and inflammation. If it turns out that an alteration of the microbiome precedes skin inflammation, the final challenge will be to seek alternatives which will help to restore the physiologic microbiome.

The human skin, our largest organ, is a complex ecosystem of diverse microorganisms, consisting of bacteria, fungi, viruses, mites and archaea. Symbiotic microorganisms protect against invasion by opportunistic pathogenic microbes and calm the immune system.

In this project, we would like to understand the composition and functional stability of microorganisms on human skin in the presence of typical exposures like desiccation, UV-radiation, temperature, moisture, pH and cosmetic products. Our insights will help us to retrieve critical information on the impact of the exposome on the archaeal and bacterial skin microbiome and to evaluate a potential use of skin probiotics.