Combined exposure to UV and PM affect skin oxinflammatory responses and it is prevented by antioxidant mix topical application: Evidences from clinical study.

BACKGROUND: Exposure to environmental stressors like particulate matter (PM) and ultraviolet radiation (UV) induces cutaneous oxidative stress and inflammation and leads to skin barrier dysfunction and premature aging. Metals like iron or copper are abundant in PM and are known to contribute to reactive oxygen species (ROS) production. AIMS: Although it has been suggested that topical antioxidant may be able to help in preventing and/or reducing outdoor skin damage, limited clinical evidence under real-life exposure conditions have been reported. The aim of the present study was to evaluate the ability of a topical serum containing 15% ascorbic acid, 0.5% ferulic acid, and 1% tocopherol (CF Mix) to prevent oxinflammatory skin damage and premature aging induced by PM + UV in a human clinical trial. METHODS: A 4-day single-blinded, clinical study was conducted on the back of 15 females (18-40 years old). During the 4 consecutive days, the back test zones were treated daily with or without the CF Mix, followed by with/without 2 h of PM and 5 min of UV daily exposure. RESULTS: Application of the CF Mix prevented PM + UV-induced skin barrier perturbation (Involucrin and Loricrin), lipid peroxidation (4HNE), inflammatory markers (COX2, NLRP1, and AhR), and MMP9 activation. In addition, CF Mix was able to prevent Type I Collagen loss. CONCLUSION: This is the first human study confirming the multipollutants cutaneous damage and suggesting the utility of a daily antioxidant topical application to prevent pollution induced skin damage.

Comparison of Pollutant Effects on Cutaneous Inflammasomes Activation.

The skin is the outermost layer of the body and, therefore, is exposed to a variety of stressors, such as environmental pollutants, known to cause oxinflammatory reactions involved in the exacerbation of several skin conditions. Today, inflammasomes are recognized as important modulators of the cutaneous inflammatory status in response to air pollutants and ultraviolet (UV) light exposure. In this study, human skin explants were exposed to the best-recognized air pollutants, such as microplastics (MP), cigarette smoke (CS), diesel engine exhaust (DEE), ozone (O3), and UV, for 1 or 4 days, to explore how each pollutant can differently modulate markers of cutaneous oxinflammation. Exposure to environmental pollutants caused an altered oxidative stress response, accompanied by increased DNA damage and signs of premature skin aging. The effect of specific pollutants being able to exert different inflammasomes pathways (NLRP1, NLRP3, NLRP6, and NLRC4) was also investigated in terms of scaffold formation and cell pyroptosis. Among all environmental pollutants, O3, MP, and UV represented the main pollutants affecting cutaneous redox homeostasis; of note, the NLRP1 and NLRP6 inflammasomes were the main ones modulated by these outdoor stressors, suggesting their role as possible molecular targets in preventing skin disorders and the inflammaging events associated with environmental pollutant exposure.