Cutaneous Responses to Systemic Iron: A Potential Role for Epidermal Turnover in Mammalian Iron Excretion

The document presents findings from a study on the relationship between systemic iron levels and epidermal turnover in mammals, suggesting that the skin may play a role in iron excretion. The study observed that primary human keratinocytes store iron as ferritin in response to exogenous iron addition and that keratinocyte proliferation and the expression of epidermal differentiation markers are influenced by iron levels. In mice, systemic iron supplementation or chelation resulted in changes in total epidermal elemental iron content. Immunofluorescence showed ferritin light chain localization to the surface epidermis and hair follicle, which was reduced by iron chelation. Additionally, the levels of epidermal differentiation markers filaggrin and loricrin were found to be iron-dependent in vivo. These results imply that epidermal turnover could be a regulated mechanism for iron excretion, aligning epidermal behavior with systemic iron levels.