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A Lower Irradiation Dose of 308 nm Monochromatic Excimer Light Might Be Sufficient for Vitiligo Treatment: A Novel Insight Gained from In Vitro and In Vivo Analyses.

ABSTRACT: A 308 nm monochromatic excimer light (MEL) is widely used to treat patients with vitiligo. However, dose optimization still needs to be clarified. This study aimed to obtain objective evidence regarding various doses of MEL irradiation, induced cell level changes in vitro, and skin level alterations in vivo. Cultured human keratinocytes were irradiated with MEL using various doses. After irradiation at low doses, stem cell factor, endothelin-1, and glycoprotein nonmetastatic melanoma protein B, factors that activate and protect melanocytes, were found to be significantly elevated in keratinocytes. After irradiation using medium and high doses, inflammatory cytokines were induced. The amount of ATP released and the level of inflammasome activation, which are known to be related to interleukin-1β activation, were also increased. The back skin of guinea pigs and mice were irradiated with MEL at varying doses. After irradiation, an increase of epidermal melanin and epidermal melanocytes was confirmed, using the minimal erythemal dose or less. In rhododendrol-induced leukoderma guinea pigs, a much lower dose of MEL irradiation was effective, when compared with the effective dose for control guinea pigs. Our results suggest that a lower irradiation dose of MEL might be sufficient and more suitable for repigmentation in vitiligo treatment.

SUBMITTER: Kuroda Y

PROVIDER: S-EPMC8508796 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background/purposePsoriasis continues to be a debilitating skin disease affecting 1-3% of the United States population. Although the effectiveness of several current biologic therapies have described this pathology as a IL-23, TNF-a and Th17-mediated disease, less invasive approaches are still in use and in need of refinement. One of these is the usage of narrow band-UVB (NB-UVB) therapy to deplete specifically intra-epidermal CD3+, CD4+ and CD8+ cells to clear psoriatic plaques.Aims/objectivesIn order to improve NB-UVB therapy, we sought to determine whether skin pre-treatment with the TLR7 agonist imiquimod (IMQ) would help increase the efficiency of the former at resolving psoriatic plaques.Materials and methodsEucerin® Original Moisturizing Lotion (topical vehicle) or Aldara® (imiquimod 5% topical cream) were applied for 5 days once daily to a maximum contiguous area of 25 cm2 (5 cm × 5 cm area). Patients were provided with sachets containing 12.5 mg of imiquimod each and were instructed to apply imiquimod (I) to two psoriasis plaques (5 sachets of imiquimod allotted to each plaque). A PHAROS excimer Laser EX-308 (Ra Medical Systems, Inc. Carlsbad, CA, USA) with an output of monochromatic 308-nm light and pulse width of 20-50 ns was used for all patients. Punch biopsies of psoriatic lesions (6 mm) were taken at 4 and 48 h after final application of topical treatment with or without excimer laser treatment. Real-time quantitative RT-PCR was performed according to manufacturer's instructions and Inmunohistochemistry was used as described before.ResultsOur results suggests that although IMQ seemed to activate the type I interferon pathway as previously described, its concomitant usage with NB-UVB for clearing psoriatic skin was ineffective. Although upregulation of genes MxA, GRAMD1A and DMXL2 suggested that IMQ treatment did induce skin changes in psoriasis patients, more optimal dosing of IMQ and NB-UVB might be necessary to achieve desired treatment responses.ConclusionThe observation that psoriasis involvement was not aggravated by usage of topical IMQ was encouraging. Additional observational studies might be necessary to further tailor the combination of IMQ with NB-UVB therapy to reliably improve the psoriatic pathology.

Project description:BackgroundIn dentistry, instruments, appliances, and body fluids such as saliva or blood are possible sources of infection. Although conventional antiseptic procedures effectively prevent infection, spittoons cannot be sanitized between each treated patient and are usually washed only with running water. However, there is currently no fast and efficient disinfection method that can be implemented between treatments. An optically filtered krypton chloride excimer lamp using ultraviolet light (Far UV-C) in the 200-230 nm wavelength range (innocuous to humans) has been recently used as a virus- and bacteria-inactivating technology. This study aimed to identify the bioburden of a dental spittoon and examine the susceptibility of two oral Streptococcus and two Enterococci to 222-nm Far UV-C by irradiating the spittoon with 222 nm Far UV-C for 5 min before evaluating the disinfection effect.MethodsBacterial analysis and real-time polymerase-chain reaction testing was used to confirm the spittoon's biological contamination. Bacterial susceptibility to a 222-nm Far UV-C was determined with a graded dose irradiation test. After each treatment, the spittoon was irradiated with 222-nm Far UV-C for 5 min, and the disinfecting effect was evaluated. Microbial analysis of the spittoon's surface was performed using the Silva database.ResultsWe found that > 97% of the microbes consisted of six bacterial phyla, whereas no viruses were found. Pseudomonas aeruginosa was frequently detected. The 1-log reduction value of two oral-derived Streptococci and two Enterococci species at 222-nm Far UV-C was 4.5-7.3 mJ/cm2. Exposure of the spittoon to 222-nm Far UV-C at 3.6-13.5 mJ/cm2 significantly decreased bacterial counts (p < 0.001).ConclusionsIrradiation with 222-nm Far UV-C at 3.6-13.5 mJ/cm2 significantly eliminates bacteria in spittoons, even when they are only rinsed with water. Hence, 222-nm Far UV-C irradiation may inhibit the risk of bacterial transmission from droplets in sink surfaces.

Project description:Effective disinfection of contaminated surfaces is essential for preventing the transmission of pathogens. In this study, we investigated the UV irradiance and wavelength distribution of a 222-nm ultraviolet C (UVC) excimer lamp and its disinfection efficacy against microorganisms in laboratory conditions. By using a carrier quantitative germicidal test with stainless steel sheets as carriers, we examined the disinfection effect of the 222-nm UVC lamp on three standard strains-Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. We tested the disinfection efficacy under different conditions by adjusting irradiation time, as well as the state and temperature of the stainless steel carriers. Our results indicated that a bacterial suspension in PBS and not-dried stainless steel carriers yielded better disinfection than in TSB and dried carriers. Additionally, carrier temperature had no significant impact on disinfection efficacy. When utilizing a bacterial suspension in PBS and non-dried carriers at a temperature of 20 °C, the three bacteria were eliminated by 222-nm UVC excimer lamp irradiation in just 15 s. In contrast, when using a bacterial suspension in TSB and dried carriers at temperatures of 20 °C, 4 °C, or - 20 °C, the three bacteria were eradicated by 222-nm UVC excimer lamp irradiation in 60 s. Comparatively, the LPM lamp required more than 10 min to achieve the same disinfection effect. Our data demonstrate that the 222-nm UVC excimer lamp has higher irradiance and a more potent microbial disinfection effect than the LPM lamp, requiring significantly less irradiation time to achieve the same disinfection effect under identical conditions. Furthermore, the 222-nm UVC excimer lamp exhibited a substantial disinfection effect on bacterial propagules at low temperatures. Our findings support the optimization of "tunnel-type" cold-chain goods disinfection devices, providing an alternative, highly efficient, and practical tool to combat the spread of SARS-CoV-2 through cold-chain systems.

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A Lower Irradiation Dose of 308 nm Monochromatic Excimer Light Might Be Sufficient for Vitiligo Treatment: A Novel Insight Gained from In Vitro and In Vivo Analyses.

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