Effect of atopic skin stressors on natural moisturizing factors and cytokines in healthy adult epidermis

Epidermal deficiency of filaggrin, and the derived natural moisturizing factors (NMF), is associated with increased risk of atopic dermatitis (AD). While filaggrin gene mutations cause filaggrin deficiency, there is limited insight in causative environmental factors. To explore the effect of selected exogenous skin stressors on NMF and skin cytokines levels in healthy adult epidermis. 40 healthy volunteers (18-49 years) were exposed to hard, soft, and chlorinated water, 0.5% SLS, house dust mite, cat allergen, staphylococcal enterotoxin B (SEB), cooling and histamine. Participants were tape-stripped and biophysiological measurements were performed. NMF was determined after 24 and 48 hours, while skin cytokines were measured after 24 hours for selected exposures. At 24 hours, a significant decrease in NMF was observed for soft (0.51±0.19) and hard water (0.61±0.32) compared to occlusion alone (0.71±0.18). Hard water led to increased levels of IL-4, IFN-ɣ and IL-10. Exposure to house dust mite and SEB led to a significant decrease in NMF after 24 hours (0.77 ±0.28 and 0.80±0.28, respectively) compared to occlusion alone (1.00±0.42). House dust mite led to an increase in IFN-ɣ, IL-2 and IL-4, as compared to the non-occluded control site. Based on experimental exposure to selected atopic skin stressors such as different water types, allergens and SEB, we conclude that NMF levels are decreased along with increased secretion of various skin cytokines in healthy individuals. Our data highlight environmental factors that might play a role in AD pathophysiology, but needs confirmation in AD patients. This article is protected by copyright. All rights reserved