BC02 Clinical demonstration and biomarker study of skin ageing, monitoring and intervention

Abstract Social pressure to maintain a tanned skin influences sun-seeking behaviour and improper use of sun protection by individuals in the UK. Exposure to solar radiation is known to increase the risk of skin cancer and accelerate skin ageing; however, its effect on the skin barrier is less well described. The skin barrier is a functional unit responsible for physical protection of the body from infectious and chemical hazards, regulation of temperature and tissue hydration. Protein components include the water transporter aquaporin-3, tight junction components claudin-1 and occludin, and a precursor to skin’s natural moisturizing factor, filaggrin. Our aims were to investigate whether (i) solar radiation induces downregulation of skin barrier components, (ii) this is moderated by application of topical sunscreen products and (iii) the addition of a false tanning agent impacts the performance of topical sunscreens regarding the skin barrier. Prior to this project, full-thickness human skin equivalents were cultured and treated with topical preparations including sunscreens, then irradiated under solar light. During this project, gene and protein expression analysis was conducted using quantitative polymerase chain reaction, Western blotting and chromogenic immunohistochemistry, targeting aquaporin-3, claudin-1, occludin and filaggrin. There was a trend of downregulation of aquaporin-3 and claudin-1 following irradiation, which was mitigated by the application of sunscreens. This was supported by increased disruption in the uniformity of immunohistochemical staining at aquaporin-3 and claudin-1 antigen sites in unprotected conditions. The tanning agent did not alter gene or protein expression. Sunscreens may protect against downregulation of the skin barrier components aquaporin-3 and claudin-1 after exposure to solar radiation. Addition of a tanning agent to a sunscreen product did not negatively impact product performance.