Non-invasive skin biomarkers quantification of psoriasis and atopic dermatitis: Cytokines, antioxidants and psoriatic skin auto-fluorescence

Background: Psoriasis and atopic dermatitis (AD) are challenging to treat due to the absence of suitable monitoring procedure and their recurrences. Alteration of skin hydrophilic biomarkers (SHB) and structural elements occur in both disorders and may possess a distinct profile for each clinical condition. Objective: To quantify skin cytokines and antioxidants non-invasively in psoriatic and in AD patients and to evaluate skin auto-fluorescence in psoriatic patients. Methods: A skin wash sampling technique was utilized to detect the expression of SHB on psoriatic and AD patients and healthy controls. Inflammatory cytokine (TNF alpha, IL-1 alpha and IL-6) levels, total antioxidant scavenging capacity and uric acid content were estimated. Additionally, measurement of the fluorescent emission spectra of tryptophan moieties, collagen cross-links and elastin cross-links were performed on psoriatic patients and healthy controls. Results: Our findings demonstrate significant alterations of the SHB levels among psoriasis, AD and healthy skin. Differences were also observed between lesional and non-lesional areas in patients with psoriasis and AD. Ultra-structural changes were found in psoriatic patients both in lesional and non-lesional areas. Conclusion: Employing non-invasive measurements of skin wash sampling and skin auto-fluorescence might serve as complementary analysis for improved diagnosis and treatment of psoriasis and AD. Furthermore, they may serve as an additional monitoring tool for various diseases, in which skin dysfunction is involved. (C) 2012 Elsevier Masson SAS. All rights reserved.