IMPROVING GENOTOXICITY TESTING: COMET ASSAY WITH 3D SKIN MODELS.

This study by scientists at Henkel, ECVAM, TNO, L’Oreal, COLIPA, Procter and Gamble – Cosmital SA, Unilever, Procter and Gamble US, Beiersdorf, KPSS (Kao Professional Salon Services), GlaxoSmithKline (GSK) and Pierre Fabre demonstrated that MatTek’s EpiDerm in vitro 3-D human skin tissue equivalent can be used in a test system of higher biological relevance compared to currently used monolayer cultures for COMET (genotoxicity) testing of cosmetics and their ingredients. Due to the 7th Amendment to the Cosmetic Directive, animal tests for acute toxicological endpoints (i.e. genotoxicity) are banned for cosmetic ingredients within the EU started March 2009. However, the currently used in vitro genotoxicity tests are less predictive. One strategy to maintain safety assessment is to improve existing test batteries with test systems of higher biological relevance compared to currently used monolayer cultures. For the skin, which is the first site of contact with max. exposure for most of the cosmetics, skin models might be appropriate test systems. The Colipa project 3D human skin models aims to adapt the epidermal skin model Epiderm™ (MatTek) to the Comet assay as a widely used and scientifically well accepted method which accounts for several persisting and transient DNA damage (i.e. single strand breaks, double strand breaks, alkali labile sites). Conclusions: • Low background in control groups provides a high dynamic range for effects of test compounds • Robust data with different cell donors • Good reproducibility between laboratories • Dose-dependent increase in % tail intensity in Epiderm treated with MMS and 4NQO across labs

7th Amendment to the Cosmetic Directive, Cell donors, Comet Assay, DNA damage, Double strand breaks, EPI-200, EpiDerm, Genotoxicity, Reproducibility, Single strand breaks

4-Nitroquinolineoxide (4NQO), Acetone, Methylmethanesulfonate (MMS)