Cellular and molecular effects of iron-based pigments on macrophages

Tattoos are becoming increasingly popular across generations, with 10-20% of the population in Europe and the United States bearing at least one tattoo. Tattoos represent an intradermal injection of pigments (i.e. coloured insoluble micro- and nano-particles), which remain in place throughout life. Although tattoos have existed for centuries, the question of their health impact has really arisen rather lately, so that a significant gap in our understanding of the cellular and molecular long-term effects of these pigments on the body remains. In this project, we investigate a wide range of tattoo pigments on macrophages. Macrophages, pivotal in pigment persistence through phagocytic processes and capture-release-recapture cycles, are also key players in the inflammatory response and tissue homeostasis. Dysregulation in macrophage functionalities can potentially lead to substantial health consequences such as deficient immune response or such as sarcoidosis. To assess the long-term effects of tattoos, we tested iron-based pigments (which are widely used in the medical field for dermopigmentation of the nipple-areola complex after mastectomy) using an exposure scheme consisting in an acute exposure for 24 hours and a 5-days post exposure recovery period. Proteomic analyses were conducted to understand the underlying cellular mechanisms.