Supplementary Material for: Lipidomics reveals the effects of detergents on skin surface lipids in young adults

Background: Detergent is a chemical product commonly used in people's daily life. Contact with detergent solutions can damage the human skin barrier and cause skin diseases. Skin surface lipids (SSLs) play a decisive role in skin barrier function. This study aimed to observe the changes of SSLs in young adults after exposure to detergent solutions to explore the underlying mechanism of skin barrier function damage. Methods: A self-controlled study on youth adults was conducted in Zhengzhou, China, in November 2020. The study lasted for a total of 1 week, and skin barrier function was assessed by trans epidermal water loss (TEWL) values. The changes of SSLs before and after exposure to the detergent with subjects were measured using ultra-performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-QTOF-MS). Results: The skin barrier function of subjects' hands was impaired after exposure to detergent (TEWL value increased, p< 0.001). A total of 520 SSLs were detected, divided into 6 main categories. The average relative abundance of these 6 major lipids decreased after exposure. Sphingolipids (mainly ceramides), free fatty acids (mainly long-chain fatty acids), cholesterol lipids, and glycerophospholipids are the most severely damaged lipids. Conclusion: Detergent solutions can damage the skin barrier function and SSLs of young hands, interventions targeting SSLs to eliminate detergent damage to human skin may be of value.研究背景：洗涤剂是人们日常生活中常用的化工产品。接触洗涤剂溶液会损伤人体皮肤屏障，进而引发皮肤疾病。皮肤表面脂质（Skin Surface Lipids, SSLs）对皮肤屏障功能起着决定性作用。本研究旨在观察青年群体接触洗涤剂溶液后皮肤表面脂质的变化，以探究皮肤屏障功能受损的潜在机制。 研究方法：2020年11月于中国郑州开展针对青年群体的自身对照研究。本次研究周期共计1周，通过经表皮失水量（Trans Epidermal Water Loss, TEWL）值评估皮肤屏障功能。采用超高效液相色谱-四极杆飞行时间质谱（Ultra-Performance Liquid Chromatography Quadrupole Time of Flight Mass Spectrometry, UPLC-QTOF-MS）检测受试者接触洗涤剂前后皮肤表面脂质的变化情况。 研究结果：受试者手部皮肤屏障功能在接触洗涤剂后出现损伤（经表皮失水量升高，p<0.001）。本次研究共检测到520种皮肤表面脂质，划分为6大类。接触洗涤剂后，这6大类脂质的平均相对丰度均出现下降。其中鞘脂类（主要为神经酰胺）、游离脂肪酸类（主要为长链脂肪酸）、胆固醇脂类及甘油磷脂类受损最为严重。 研究结论：洗涤剂溶液可损伤青年手部皮肤屏障功能及皮肤表面脂质，靶向皮肤表面脂质的干预手段以消除洗涤剂对人体皮肤的损伤或具有应用价值。