Nishijo Taku, Miyazawa Masaaki, Saito Kazutoshi, Otsubo Yuki, Mizumachi Hideyuki, Sakaguchi Hitoshi
Safety Science Research Laboratories, Kao Corporation.
J Toxicol Sci. 2019;44(1):13-21. doi: 10.2131/jts.44.13.
Cosmetic ingredients are often complex mixtures from natural sources such as botanical extracts that might contain minute amounts of constituents with sensitizing potential. The sensitivity of in vitro skin sensitization test methods such as KeratinoSens and h-CLAT for the detection of minute amounts of sensitizer in mixtures remains unclear. In this study, we assessed the detection sensitivity of the binary test battery comprising KeratinoSens and h-CLAT for minute amounts of sensitizers by comparing the LLNA EC3 (estimated concentration of a substance expected to produce a stimulation index of 3) values to the minimum detection concentrations (MDCs) exceeding the positive criteria for each of the two in vitro test methods. 146 sensitizers with both sets of in vitro data and LLNA data were used. MDC values for KeratinoSens and h-CLAT were calculated from exposure concentrations exceeding positive criteria for each in vitro test method (EC1.5 and minimum induction thresholds, respectively). The dilution rate used to expose culture medium was also considered. For 86% of analyzed sensitizers, the in vitro test methods showed MDC values lower than LLNA EC3 values, suggesting that the binary test battery with KeratinoSens and h-CLAT have greater sensitivity for detection of minute amounts of sensitizer than LLNA. These results suggest the high applicability of KeratinoSens and h-CLAT for detecting skin sensitizing constituents present in botanical extract.
化妆品成分通常是来自天然来源的复杂混合物，如植物提取物，其中可能含有微量具有致敏潜力的成分。对于检测混合物中微量致敏剂的体外皮肤致敏试验方法，如角质形成细胞传感试验（KeratinoSens）和人细胞系激活试验（h-CLAT），其灵敏度尚不清楚。在本研究中，我们通过将限量稀释法（LLNA）的半数有效浓度（EC3，预计产生刺激指数为3的物质浓度）值与超过两种体外试验方法各自阳性标准的最低检测浓度（MDC）进行比较，评估了由KeratinoSens和h-CLAT组成的二元试验组合对微量致敏剂的检测灵敏度。使用了146种具有两组体外数据和LLNA数据的致敏剂。KeratinoSens和h-CLAT的MDC值是根据超过每种体外试验方法阳性标准的暴露浓度（分别为EC1.5和最低诱导阈值）计算得出的。还考虑了用于暴露培养基的稀释率。对于86%的分析致敏剂，体外试验方法显示MDC值低于LLNA EC3值，这表明由KeratinoSens和h-CLAT组成的二元试验组合比LLNA对检测微量致敏剂具有更高的灵敏度。这些结果表明KeratinoSens和h-CLAT在检测植物提取物中存在的皮肤致敏成分方面具有很高的适用性。
