Ex-vivo determination of antifungal activity of a new prescription non- steroidal facial cream against Malassezia furfur in human skin explants Fall Clinical Dermatology Conference® October 12-15, 2017. Las Vegas, Nevada, USA INTRODUCTION Malassezia furfur (MF) is a lipophilic (lipid-dependent) fungus that is part of normal human skin flora that grow on the sebaceous areas of human skin, including the face, scalp, and upper trunk. Although part of the normal human skin flora, uncontrolled MF proliferation in some patients leads to development of skin diseases including tinea versicolor, pityrosporum folliculitis, and seborrheic dermatitis (SD). The objective of this study was to examine the anti-fungal properties of a new non-steroidal facial cream (NSFC) in human organotypic skin cultures (hOSCs) inoculated with MF in an ex-vivo model. This model was developed to mimic SD conditions in order to evaluate the antifungal properties of an NSFC product containing zinc PCA, piroctone olamine, dihydroavenanthramide, biosaccharide gum-2 and stearyl glycyrrhetinate. MF suspension was placed on the skin surface and incubated for 24 hours under conditions that are optimal for MF growth. 24 hours post initial MF inoculation, NSFC was topically applied on skin explants (2 mg/cm2). On control skin explants, inoculated in the same way, no product was applied. A sham control group was treated with a neutral cream without known antifungal properties. Growth of MF was monitored by quantifying MF Colony Forming Units (CFUs) in a sample removed from skin surface. The quantification of CFUs was carried out by recovering fungal microorganisms from skin explants and subsequent plating them following the serial dilution method to determine the number of CFUs (Figure 2). RESULTS In the altered skin explants, inoculation with MF led to successful colonization as indicated by the significant increase in MF CFUs compared to baseline: a 2-fold increase at 24 hours. The topical application of NSFC significantly reduced (p<0.05) the number of MF CFUs by 90% compared to the untreated control group. The sham control treated with neutral cream did not lead to a significant reduction of the MF population (15% decrease in CFUs) (Figure 3). ISDIN S.A.Provencals, 33 Barcelona Spain M. Furfur quantification C .F .U . 3000000 2500000 2000000 1500000 1000000 500000 0 Control 0C.F.U M.Furfur 1635000 NSFC Vaseline 152800 1560000 Figura 1. Skin samples images stained with violet crystal. A) Control B) M.Furfur C) M. Furfur + NSFC D) M. Furfur + Vaseline Figura 3. M. furfur population and response to NSFC application. Significant decrease in M. Furfur colonies in skin treated with NSFC. (*)=p<0.05 Negative control. No M. Furfur No NFSC (5 skin replicates) Figura 2. Study design ex-vivo model with Human skin. NSFC: Non-steroidal facial cream Partial tape striping Skin samples without M. Furfur No product application 48h 24h M.Furfur CFU & picture 24h Malassezia inoculation with No NSFC (5 skin replicates) Partial tape striping Malassezia furfur incubation (106 UFC) No product application 48h 24h M.Furfur CFU & picture 24h Malassezia inoculation with NSFC (5 skin replicates) Partial tape striping Malassezia furfur incubation (106 UFC) NSFC 48h 24h M.Furfur CFU & picture 24h Malassezia inoculation with Vaseline (5 skin replicates) Partial tape striping Malassezia furfur incubation (106 UFC) Vaseline application 48h 24h M.Furfur CFU & picture 24h A B C D * METHODS Human organotypic skin cultures hOSCs were obtained from abdominal skin removed during cosmetic surgery. The explants were altered by partial elimination of stratum corneum to facilitate colonization and stabilization of the MF (Figure 1). CONCLUSIONS In this ex-vivo model, the topical application of a new NSFC significantly reduced the MF CFU count. These findings demonstrate the antifungal properties of this NSFC, specifically for MF, a key contributing fungus in Seborrheic Dermatitis. REFERENCIAS: 1.Gupta AK., et al. Seborrheic dermatitis of the scalp: etiology and treatment. J Drugs Dermatol. 2004;3(2):155-8. 2.Barac A., et al. Presence, species distribution, and density of Malassezia yeast in patients with seborrhoeicdermatitis - a community-based case-control study and review of literature. Mycoses. 2015;58(2):69-75. 3.Tajima M., et al. Molecular analysis of Malassezia microflora in seborrheic dermatitis patients: comparison with other diseases and healthy subjects. J Invest Dermatol. 2008 Feb;128(2):345-51. Epub 2007 Aug 2. Granger C.1, Goñi-de-Cerio F.2, Martínez-Masana G.1, Garre A1. 1. Innovation and Development, ISDIN S.A. Barcelona, Spain. 2. GAIKER-IK4 Technology Centre. Parque Tecnológico Ed 202, Zamudio, Vizcaya, Spain. FC17PosterISDINexvivoGranger.pdf