Presented at the 16th DGK Symposium, March 2–4, 2005, Leipzig, Germany – Received the Award for the Best Poster Presentation 1 Influencing the equilibrium of the cutaneous ecosystem to improve the properties of skin prone to acne

Abstract

The skin is colonized by a variety of microorganisms such as Propionibacterium acnes, Staphylococcus epidermidis and Malassezia furfur that are in a stable balance and form the resident skin flora. The homeostasis of this ecosystem is of fundamental importance as it plays a barrier role by limiting the invasion and growth of pathogenic bacteria on the skin surface. An internal or external change in the skin environment, a transitory lack of hygiene, a change in hormone status or hyperseborrhea can upset this balance at any time and enable the proliferation of saprophytic skin microorganisms or contamination by pathogens. Hyperseborrhea causes retention lesions such as open comedos and closed microcysts that can be transformed into papulae, pustules or nodules in the case of an inflammatory reaction caused by abnormal bacterial proliferation. These skin disorders are particularly pronounced between the ages of 12 and 25 but nonetheless affect all ages and cause oily skin accompanied by unsightly imperfections that are difficult to camouflage and live with. The skin combats microbial infections with its natural defense system. Keratinocytes produce and secrete a large number of peptides with direct and indirect antimicrobial activity (cathelicidins, β‐defensins). These natural antimicrobial peptides limit the proliferation of pathogenic bacteria and fungi such as Staphylococcus aureus or Candida albicans and can also induce an indirect immune response. They are indispensable for the homeostasis of the cutaneous ecosystem and are over‐expressed by keratinocytes in response to an inflammatory stimulus or an infection. When these natural defenses are disturbed or overwhelmed, they must be stimulated to limit the inflammatory reactions that result in the appearance of skin imperfections such as acne. To this end, we have developed an extract purified from Filipendula ulmaria (meadowsweet) that is rich in phenolic acids. Tested at 1% on human keratinocytes, the F. ulmaria extract stimulated the natural defense functions of the skin by boosting the synthesis of cathelicidins by 130%. In addition, when tested in vivo at 4%, the F. ulmaria extract significantly reduced the lipid index by 12% in 71% of volunteers after 28 days of twice‐daily treatment. The F. ulmaria extract stimulates the natural defense functions of the skin, preventing the proliferation of bacteria on the skin surface and thereby limiting complications from acne: The number of spots and their total occupied surface were significantly reduced by ‐10% and ‐12%, respectively. Finally, dermatological evaluation after 28 days of twice‐daily use showed the capacity of the F. ulmaria extract to significantly improve the quality of skin prone to acne: The homogeneity of skin grain was improved (+21%), the number of inflammatory lesions reduced (‐20%) and the infiltration of lesions decreased (‐22%).