Full-body blue light irradiation as treatment for atopic dermatitis: a randomized sham-controlled clinical trial (AD-Blue).

BACKGROUND: Visible blue light (wavelength 400-495 nm) is a promising new treatment option for both psoriasis and atopic dermatitis (AD). Whilst previous clinical trials featured various devices and blue light at a variety of wavelengths, none of these interventions were challenged in objective clinical criteria. PATIENTS AND METHODS: Eighty-seven patients diagnosed with AD were enrolled in AD-Blue, an international, prospective, double-blinded, three-armed (415 nm vs. 450 nm vs. sham control), randomized trial designed to investigate the safety and efficacy of prototype full-body blue light devices. RESULTS: Full-body irradiation with 450 nm blue light but not 415 nm had a significant impact on itch (Itch-VAS, -1.6 ± 2.3; p  =  0.023 vs. sham irradiation). PO-SCORAD values also decreased significantly in response to irradiation at 415 nm (-11.5 ± 18.4; p = 0.028 vs. sham irradiation). None of the other outcome measures (EASI, SCORAD, IGA, DLQI) changed significantly. No safety signals were observed. Evaluation of skin transcriptomes, cytokine levels in serum, and ELISpots from peripheral blood mononuclear cells isolated from a subset of patients revealed moderate decreases in IL-31 in response to irradiation with blue light. CONCLUSIONS: Despite its favorable safety profile and moderate reductions in itch and IL-31 levels, full-body blue light irradiation did not lead to an amelioration of any of the objective measures of AD.

Characterization of disease-specific cellular abundance profiles of chronic inflammatory skin conditions from deconvolution of biopsy samples.

BACKGROUND: Psoriasis and atopic dermatitis are two inflammatory skin diseases with a high prevalence and a significant burden on the patients. Underlying molecular mechanisms include chronic inflammation and abnormal proliferation. However, the cell types contributing to these molecular mechanisms are much less understood. Recently, deconvolution methodologies have allowed the digital quantification of cell types in bulk tissue based on mRNA expression data from biopsies. Using these methods to study the cellular composition of the skin enables the rapid enumeration of multiple cell types, providing insight into the numerical changes of cell types associated with chronic inflammatory skin conditions. Here, we use deconvolution to enumerate the cellular composition of the skin and estimate changes related to onset, progress, and treatment of these skin diseases. METHODS: A novel signature matrix, i.e. DerM22, containing expression data from 22 reference cell types, is used, in combination with the CIBERSORT algorithm, to identify and quantify the cellular subsets within whole skin biopsy samples. We apply the approach to public microarray mRNA expression data from the skin layers and 648 samples from healthy subjects and patients with psoriasis or atopic dermatitis. The methodology is validated by comparison to experimental results from flow cytometry and immunohistochemistry studies, and the deconvolution of independent data from isolated cell types. RESULTS: We derived the relative abundance of cell types from healthy, lesional, and non-lesional skin and observed a marked increase in the abundance of keratinocytes and leukocytes in the lesions of both inflammatory dermatological conditions. The relative fraction of these cells varied from healthy to diseased skin and from non-lesional to lesional skin. We show that changes in the relative abundance of skin-related cell types can be used to distinguish between mild and severe cases of psoriasis and atopic dermatitis, and trace the effect of treatment. CONCLUSIONS: Our analysis demonstrates the value of this new resource in interpreting skin-derived transcriptomics data by enabling the direct quantification of cell types in a skin sample and the characterization of pathological changes in tissue composition.

Blue light exposure decreases systolic blood pressure, arterial stiffness, and improves endothelial function in humans.

AIMS: Previous studies have shown that ultraviolet light can lead to the release of nitric oxide from the skin and decrease blood pressure. In contrast to visible light the local application of ultraviolet light bears a cancerogenic risk. Here, we investigated whether whole body exposure to visible blue light can also decrease blood pressure and increase endothelial function in healthy subjects. METHODS: In a randomised crossover study, 14 healthy male subjects were exposed on 2 days to monochromatic blue light or blue light with a filter foil (control light) over 30 minutes. We measured blood pressure (primary endpoint), heart rate, forearm vascular resistance, forearm blood flow, endothelial function (flow-mediated dilation), pulse wave velocity and plasma nitric oxide species, nitrite and nitroso compounds (secondary endpoints) during and up to 2 hours after exposure. RESULTS: Blue light exposure significantly decreased systolic blood pressure and increased heart rate as compared to control. In parallel, blue light significantly increased forearm blood flow, flow-mediated dilation, circulating nitric oxide species and nitroso compounds while it decreased forearm vascular resistance and pulse wave velocity. CONCLUSION: Whole body irradiation with visible blue light at real world doses improves blood pressure, endothelial function and arterial stiffness by nitric oxide released from photolabile intracutanous nitric oxide metabolites into circulating blood.

Biological effects of nitric oxide generated by an atmospheric pressure gas-plasma on human skin cells.

Physical plasmas which contain a mixture of different radicals, charged species and UV-radiation, have recently found entry in various medical applications. Though first clinical trials are underway nothing is known about the plasma components mediating the biological effects seen and safety concerns have been neglected. We here use for the first time a plasma device equipped with a bent quartz capillary to omit UV-radiation by directing the gas flux only, containing high concentrations of NO, onto cultured human skin cells. This enables us to compare the effects of plasma produced radical species alone - mainly NO - and in combination with the also emitted UV-radiation on cells. Evaluation of cell death after different treatment times with the capillary present shows no sign of apoptosis in primary human keratinocytes even after 15 min plasma exposure. In human skin endothelial cells however, toxicity is elevated after treatment for more than 10 min. In contrast, without the capillary treatment of both cell types results in maximal cell death after 10 min. Measuring nitrite and nitrosothiols reveals that plasma-treatment leads to an increase of these NO-products in buffer solution and cell culture medium. Using an intracellular fluorescent NO-probe and analysing the nitrosation status of plasma exposed skin cells we can prove that NO indeed reaches and penetrates into these cells. Non-toxic exposure times modulate proliferation in both cell types used, indicating that the gas species, mainly NO, are biological active.