CAROLE VIALLEIX¹, THIBAULT MICHEL¹, JEAN-PAUL CADORET¹,
ASSIA DREUX³, JEAN-YVES BERTHON², EDITH FILAIRE2,4*
*Corresponding author
1. Greensea. Promenade Sergent Jean Louis Navarro, Mèze, France
2. Greentech. Biopôle Clermont-Limagne, Saint Beauzire, France
3. Biovitis, Le Bourg, Saint-Etienne de Chomeil, France
4. University Clermont Auvergne, UMR 1019 INRA-UcA, UNH (Human Nutrition Unity),
ECREIN Team, Clermont-Ferrand, France

Abstract

The treatment of sensitive skin represents excellent target for ingredients in cosmetics. The involvement of microbial communities in sensitive pathophysiology is unknown. We performed a study to examine 1) the effects of Halymenia durvillei (Hd) active ingredient, a red alga, using an ex vivo and in vivo model on inflammation and neurosensory discomfort 2) the characterization of the skin microbiota before and after 15 days of Hd active ingredient application. Hd active ingredient calms feelings of discomfort and redness, and controls the microvascularization. Our data demonstrate that specific bacterial genus and species are associated with sensitive and reactive skin. Hd active ingredient decreases the proportion of Corynebacterium and particularly Corynebacterium kroppenstedtii and increases the Chryseobacterium genus, showing that Hd active ingredient promoted the development of specific bacteria.

INTRODUCTION

The skin is constantly exposed to various endogenous, exogenous and life style factors that may affect the skin barrier function at the physical, mechanical and microbial levels. The resulting impact can potentially lead to inflammatory skin conditions involving sensitive or irritated skin as well as chronic inflammatory skin diseases, allergies or autoimmune diseases. These endogenous and exogenous factors are included in the exposome concept, which was proposed by Wild (1) to encompass “the totality of human environmental exposures from conception onwards, complementing the genome”. More recently, Miller and Jones (2) proposed an alternative definition of the exposome, which explicitly incorporates behavioural risk factors, the body’s response to environmental influences, and the endogenous metabolic processes that could alter or process the chemicals to which humans are exposed. Increasing attention is being paid to the exposome of human skin. Mirroring the cutaneous responses to environmental stress (3), the major environmental factors that contribute to skin alterations have been recently regrouped in the so- called “skin aging exposome� ...