MUTZ-3 derived Langerhans cells in human skin equivalents: a platform to elucidate the allergic potential and distinguish irritant exposure of ingredients used in permanent hair dyes

• Grant number: 15/23702-6
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Effective date (Start): April 15, 2016
• Effective date (End): April 14, 2017
• Field of knowledge: Health Sciences - Pharmacy
• Principal Investigator: Silvya Stuchi Maria-Engler
• Grantee: Thalita Boldrin Zanoni
• Supervisor: Susan Gibbs
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Research place: University Amsterdam (VU), Netherlands
• Associated to the scholarship: 14/15224-4 - Toxic and immunotoxic evaluation of permanent hair dyes using artificial skin: alternative measures for animal experimentation, BP.PD

Abstract

Nowadays billions of people use hair dyes, among them, the most representative class are the permanent hair dyes reaching up to 80% of worldwide consumption. Permanent hair dyes are formed after successive reactions between a primary intermediate (ex. p-phenylenediamine) and a coupler (ex. Resorcinol) that after oxidative reactions with hydrogen peroxide (H2O2) results in permanent color changes inside the hair shaft. In 2001, the European Union began re-evaluating the toxicity of hair dyes. Since 2007, 85 hair dyes have been banned for not being considered safe for consumers. During a hair dying procedure, human skin is the primary route of exposure to these chemicals. Considering the exposed, the present project aims to evaluate the toxic and sensitization potential of two hair dyes largely used in permanent hair dyes formulations, these are p-toluenediamine (PTD) and p-aminophenol (MAF), precursor and coupler agent respectively. The reaction products between the ingredients in oxidative conditions have been analyzed using analytical methods such as liquid chromatography linked to mass spectrometry. So far we have evaluated the toxic potential of these compounds and its mixtures, our results show that the mixture of the three components used for permanent hair dyes (simulating a real hair dye exposure) is more hazard to epidermal and full thickness skin reconstructs leading to basal cell vacuolization, breakage of lipids present on the stratum corneum and DNA fragmentation induce by apoptosis. Next, using epidermal equivalents we have observed that cytokines involved in skin sensitization process (IL-18 and IL-1±) have increased when ingredients are combined among them, also, the increases levels of these cytokines are proportional to the toxic effects observed in skin reconstructs. These findings indicates that sensitization potential is increased after topical exposure of permanent hair dye mixtures when compared to each ingredient alone, for this we believe that the next pathway to be investigated would be the specific sensitization mechanism involved in human skin using immunocompetent skin models that contain dendritic cells for this, we are proposing to develop with the collaboration of Prof. Dr. Susan Gibbs on the BEPE project. The development of both of these in vitro techniques should contribute globally to the establishments of new methodologies that are able substitute animal testing. The development of an immunocompetent skin is a new methodology in Brazil, which promises to bring scientific and pioneering innovations in both, national and international levels. Finally this project aims to contribute to advances in understanding the allergenic and toxic potential of components regularly used in permanent hair dyes using very promising scientific innovative methodology's. (AU)