Mechanisms of ultraviolet (UV) B and UVA phototherapy

Exploring the Influence of Cold Plasma on Epidermal Melanogenesis In Situ and In Vitro

Epidermal melanin synthesis determines an individual's skin color. In humans, melanin is formed by melanocytes within the epidermis. The process of melanin synthesis strongly depends on a range of cellular factors, including the fine-tuned interplay with reactive oxygen species (ROS). In this context, a role of cold atmospheric plasma (CAP) on melanin synthesis was proposed due to its tunable ROS generation. Herein, the argon-driven plasma jet kINPen® MED was employed, and its impact on melanin synthesis was evaluated by comparison with known stimulants such as the phosphodiesterase inhibitor IBMX and UV radiation. Different available model systems were employed, and the melanin content of both cultured human melanocytes (in vitro) and full-thickness human skin biopsies (in situ) were analyzed. A histochemical method detected melanin in skin tissue. Cellular melanin was measured by NIR autofluorescence using flow cytometry, and a highly sensitive HPLC-MS method was applied, which enabled the differentiation of eu- and pheomelanin by their degradation products. The melanin content in full-thickness human skin biopsies increased after repeated CAP exposure, while there were only minor effects in cultured melanocytes compared to UV radiation and IBMX treatment. Based on these findings, CAP does not appear to be a useful option for treating skin pigmentation disorders. On the other hand, the risk of hyperpigmentation as an adverse effect of CAP application for wound healing or other dermatological diseases seems to be neglectable.

Nb-UVB and PUVA therapy in treating early stages of Mycosis Fungoides: A single-center cross-sectional study

INTRODUCTION

Mycosis fungoides (MF) and Sezary Syndrome are the most common forms of cutaneous T-cell lymphoma. Early-stage MF is known to have an indolent behavior, and the EORTC guidelines recommend treating patients with skin-directed therapies, such as phototherapy, instead of systemic therapies. Phototherapy is a popular therapeutic option, with two commonly used light sources-PUVA and narrow band-nb UVB. PUVA is less commonly used due to its potential carcinogenic role, but it has systemic effects, while nb-UVB has mostly skin-limited effects. There is ongoing debate regarding the role of UVB light, and in 2021, the Cutaneous Lymphoma Italian Study Group reached a consensus on technical schedules for NB-UVB and PUVA for MF. This study aims to analyze and compare the efficacy of the two phototherapy options in treating early-MF patients.

MATERIALS AND METHODS

The study included patients diagnosed with stage IA/B MF in the last 10 years, who had at least 12 months of follow-up data and a minimum of 24 phototherapy sessions (PUVA or nb UVB) and treated with topical steroids apart from phototherapy.

RESULTS

Results showed that the two phototherapy options were similarly effective in treating early MF, with no significant differences in clinical response, although PUVA was associated with more adverse effects.

CONCLUSIONS

The study provides valuable insights into the use of phototherapy in early MF, and the results can be used to guide treatment decisions and improve patient outcomes.

Narrowband ultraviolet B phototherapy for pityriasis lichenoides: A real-life experience

INTRODUCTION

Pityriasis lichenoides (PL) is a papulosquamous disease affecting both children and adults, for which narrowband-UVB (NB-UVB) phototherapy is regarded as a commonly used treatment option. The aim of this study was to investigate the efficacy of NB-UVB phototherapy in the management of PL and to compare response rates in pediatric and adult age groups.

MATERIALS AND METHODS

This observational, retrospective study included 20 PL patients (12 pityriasis lichenoides chronica; PLC, 8 pityriasis lichenoides et varioliformis acuta; PLEVA) who failed to respond to other treatment modalities. The data for this study were collected retrospectively from patient follow-up forms in the phototherapy unit.

RESULTS

A complete response (CR) was obtained in all pediatric patients with PL, while 53.8% of adult patients had achieved CR. The mean cumulative dose required to achieve the CR was higher in pediatric patients than adult patients with PL (p < .05). The CR was achieved in 6 (75%) of 8 PLEVA patients, while 8 (66.7%) of 12 PLC patients had reached to CR. The mean number of exposures for patients with PLC to achieve a CR was higher than patients with PLEVA (p < .05). Erythema was the most common adverse effect during phototherapy particularly in 5 (35.7%) of the patients with PL who had achieved CR.

CONCLUSIONS

NB-UVB is an effective and well-tolerated treatment option for PL especially in diffuse types. A higher response can be obtained in children with higher cumulative dose. Patients with PLC may require more exposures for CR than patients with PLEVA.

A retrospective, descriptive study of patients with Mycosis fungoides treated by phototherapy (oral PUVA, NB-UVB) with a twice-weekly regimen at the Institute of Dermatology, Bangkok, Thailand, with an experiential timeline of 13 years

BACKGROUND

Phototherapy has been a first-line treatment for early-stage mycosis fungoides (MF) since 1976. Oral 8-methoxypsoralen plus ultraviolet A (oral PUVA) and narrow-band ultraviolet B (NB-UVB) are favorable modalities owing to their availability. In previous studies, phototherapy was conducted thrice per week initially, which is not feasible for many patients.

OBJECTIVES

To evaluate the initial clinical responses and time to relapse in patients with early-stage MF treated with oral PUVA and NB-UVB at a twice-weekly regimen.

METHODS

We reviewed the records of patients with biopsy-proven MF who received oral PUVA or NB-UVB in 2002-2014. Demographic data, staging, response to initial course of phototherapy, and initial relapse-free interval were collected.

RESULTS

Among 70 patients, 14 (20%) and 56 (80%) were treated with oral PUVA and NB-UVB, respectively. The majority had early-stage MF (IA, 22.9%, IB, 57.1%, and IIA, 4.3%). Oral PUVA led to a complete response (CR) in 2 (14.3%) patients and partial response (PR) in 7 (50%) patients; 17 (30.4%) and 25 (44.6%) patients, respectively, achieved CR and PR with NB-UVB. The number of treatments was similar in both groups. The cumulative dose was 520.7 J/cm² for PUVA and 41.6 J/cm² for NB-UVB. There was no initial relapse in the 2 (100%) patients and in 10 (58.8%) patients treated with oral PUVA and NB-UVB at 18 months and 9.14 months of follow-up, respectively.

CONCLUSION

Patients with early-stage MF can achieve clinical response with oral PUVA and NB-UVB, with a twice per week regimen. The initial relapse-free interval was longer than 1 year.

A deep dive into UV-based phototherapy: Mechanisms of action and emerging molecular targets in inflammation and cancer

UV-based phototherapy (including psoralen plus UVA (PUVA), UVB and UVA1) has a long, successful history in the management of numerous cutaneous disorders. Photoresponsive diseases are etiologically diverse, but most involve disturbances in local (and occasionally systemic) inflammatory cells and/or abnormalities in keratinocytes that trigger inflammation. UV-based phototherapy works by regulating the inflammatory component and inducing apoptosis of pathogenic cells. This results in a fascinating and complex network of simultaneous events-immediate transcriptional changes in keratinocytes, immune cells, and pigment cells; the emergence of apoptotic bodies; and the trafficking of antigen-presenting cells in skin-that quickly transform the microenvironment of UV-exposed skin. Molecular elements in this system of UV recognition and response include chromophores, metabolic byproducts, innate immune receptors, neurotransmitters and mediators such as chemokines and cytokines, antimicrobial peptides, and platelet activating factor (PAF) and PAF-like molecules that simultaneously shape the immunomodulatory effects of UV and their interplay with the microbiota of the skin and beyond. Phototherapy's key effects-proapoptotic, immunomodulatory, antipruritic, antifibrotic, propigmentary, and pro-prebiotic-promote clinical improvement in various skin diseases such as psoriasis, atopic dermatitis (AD), graft-versus-host disease (GvHD), vitiligo, scleroderma, and cutaneous T-cell lymphoma (CTCL) as well as prevention of polymorphic light eruption (PLE). As understanding of phototherapy improves, new therapies (UV- and non-UV-based) are being developed that will modify regulatory T-cells (Treg), interact with (resident) memory T-cells and /or utilize agonists and antagonists as well as antibodies targeting soluble molecules such as cytokines and chemokines, transcription factors, and a variety of membrane-associated receptors.

The impact of medium dose UVA1 phototherapy on pruritus, DLQI and SCORAD index in patients with atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is featured by pruritus, which causes diminished quality of life. Little clinical data exists concerning the use, efficacy and side effects of UVA1 phototherapy in AD patients.

AIM

To determine the effectiveness of medium-dose UVA1 phototherapy in AD treatment.

MATERIAL AND METHODS

Thirty-six patients with AD were irradiated with medium-dose UVA1 (45 J/cm2) as monotherapy for 4 weeks for a total of 20 sessions (daily irradiations during weekdays only). Clinical status was evaluated with the visual analogue scale for pruritus, Dermatology Life Quality Index (DLQI) for evaluating general well-being and the SCORAD index. All parameters were measured twice: before and after phototherapy.

RESULTS

UVA1 phototherapy resulted in a significant (p < 0.001) decrease in pruritus, improvement in DLQI (p < 0.001) and SCORAD (p < 0.001). Before phototherapy, the intensity of pruritus and SCORAD index correlated with DLQI (r = 0.34, p < 0.05 and r = 0.61, p < 0.05, respectively). Similarly, after irradiation, pruritus correlated with DLQI, and SCORAD index correlated with DLQI (r = 0.51, p < 0.05 and r = 0.55, p < 0.05, respectively). No severe adverse effects were noted during the study.

CONCLUSIONS

Phototherapy with medium-dose UVA1 irradiation exerts a significant antipruritic effect, decreases the severity of the disease and improves the quality of life of AD patients. This technique can therefore be used as a safe and effective treatment method.

Current Perspectives on the Management of Infantile Atopic Dermatitis

Atopic dermatitis (AD) is a common disease of childhood, and infantile AD may manifest from birth to 2 years. Guidelines for the management of infantile AD are lacking, and our aim is to provide a comprehensive review of best practices and possible interventions. We will focus on topical therapy, since the use of systemic immunomodulating agents in infantile AD is rarely advised. Topical agents include emollients, topical corticosteroids (TCS), topical calcineurin inhibitors (TCIs), and phosphodiesterase 4 (PDE-4) inhibitors. We will also provide a brief overview of promising emerging therapies currently under investigation in the pediatric population.

Early transcriptional changes after UVB treatment in atopic dermatitis include inverse regulation of IL-36γ and IL-37

Phototherapy with narrow-band Ultraviolet B (nb-UVB) is a major therapeutic option in atopic dermatitis (AD), yet knowledge of the early molecular responses to this treatment is lacking. The objective of this study was to map the early transcriptional changes in AD skin in response to nb-UVB treatment. Adult patients (n = 16) with AD were included in the study and scored with validated scoring tools. AD skin was irradiated with local nb-UVB on day 0, 2 and 4. Skin biopsies were taken before and after treatment (day 0 and 7) and analysed for genome-wide modulation of transcription. When examining the early response after three local UVB treatments, gene expression analysis revealed 77 significantly modulated transcripts (30 down- and 47 upregulated). Among them were transcripts related to the inflammatory response, melanin synthesis, keratinization and epidermal structure. Interestingly, the pro-inflammatory cytokine IL-36γ was reduced after treatment, while the anti-inflammatory cytokine IL-37 increased after treatment with nb-UVB. There was also a modulation of several other mediators involved in inflammation, among them defensins and S100 proteins. This is the first study of early transcriptomic changes in AD skin in response to nb-UVB. We reveal robust modulation of a small group of inflammatory and anti-inflammatory targets, including the IL-1 family members IL36γ and IL-37, which is evident before any detectable changes in skin morphology or immune cell infiltrates. These findings provide important clues to the molecular mechanisms behind the treatment response and shed light on new potential treatment targets.

[To the question of the possibility of using selective chromotherapy for allergic diseases in children]

Allergic diseases are a common pathology in childhood. In the comprehensive medical rehabilitation of children with allergic pathology, non-drug methods of treatment are widely used, which help to reduce the number of drugs used, achieve and prolong the remission of the disease, favorably affect the clinical and functional indicators.

THE PURPOSE OF THE STUDY

Is the scientific justification for the use of selective chromotherapy in children with bronchial asthma (BA) and atopic dermatitis (AD).

MATERIAL AND METHODS

The study included 120 children with allergic diseases (BA and AD). Among 100 patients with BA, the main group included 50 children, who received exposure to monochromatic polarized green light on biologically active zones for 10 days, 50 - a comparison group that did not receive physiotherapy. The main group of children with AD included 10 patients who received selective blue chromotherapy for foci of skin lesions; the comparison group included 10 children who used only moisturizers without physiotherapy methods. In order to assess the effectiveness of the impact of physical factors in all patients, clinical and functional studies were conducted in the dynamics before and after treatment.

RESULTS AND DISCUSSION

The results of clinical and functional examinations showed high therapeutic efficacy of the use of monochromatic polarized green light in children with BA (92.0%). The effectiveness of treating children with blood pressure AD using monochromatic polarized light (blue) was 80%. Indications for the use of selective chromotherapy in children with allergic diseases have been developed. For children with BA, selective chromotherapy of the green spectrum is indicated in the presence of a mild to moderate course of the disease, a period of incomplete remission, and an increased level of anxiety. It is advisable to prescribe selective chromotherapy of the blue spectrum to children with a moderate and mild course of AD.

CONCLUSION

The positive effect of selective chromotherapy of the green spectrum on the clinical course of BA in children, bronchial patency, the functional state of the central nervous system and its autonomic part, and the psychoemotional status of children have been identified. The use of selective blue spectrum chromotherapy in children with AD helps to decrease the severity of objective symptoms, reduce the intensity of itching and sleep disturbance, as well as a marked decrease in the area of skin lesion.

Biological effects of a new ultraviolet A1 prototype based on light-emitting diodes on the treatment of localized scleroderma

Ultraviolet A₁ (UVA₁ ) phototherapy (spectral range 340-400 nm) is a well-established treatment option for various skin diseases such as localized scleroderma. Recent improvements of conventional UVA₁ light sources (metal-halide or fluorescent lamps) have brought attention to a new light-emitting diode (LED) technology with remarkable advantages in handling and clinical routine. This study provides a preclinical histological and molecular evaluation of an LED-based UVA₁ prototype with a narrower spectral range (360-400 nm) for treating localized scleroderma. Scleroderma mouse models and fibroblasts in vitro were exposed to LED-based UVA₁ phototherapy or to irradiation with a commercially available metal-halide lamp emitting low-dose (20, 40 J/cm² ), medium-dose (60 J/cm² ) and high-dose (80, 100 J/cm² ) UVA₁ light. Both UVA₁ light sources affected inflammatory genes (IL-1α and IL-6) and growth factors (TGFß-1 and TGFß-2). Increased collagen type 1 was reduced after UVA₁ phototherapy. Matrix metalloproteinase-1 was more enhanced after a medium dose of LED-based UVA₁ phototherapy than after conventional treatment. In vivo, dermal thickness and the amount of collagen were reduced after both treatment methods. Remarkably, myofibroblasts were more effectively reduced by a medium dose of LED-based UVA₁ phototherapy. The study indicates that LED-based UVA₁ phototherapy yields similar or even better results than conventional treatment. In terms of biosafety and patient comfort, LED-based UVA₁ phototherapy offers clear advantages over conventional treatment because of the use of a narrower and less harmful UVA₁ spectrum, less heat generation and shorter treatment times at the same irradiation intensity. Clinical studies are required to confirm these results in patients with localized scleroderma.

Comparison of Narrowband UV-B With Psoralen-UV-A Phototherapy for Patients With Early-Stage Mycosis Fungoides: A Systematic Review and Meta-analysis

Importance

Phototherapy is one of the mainstays of treatment for early mycosis fungoides (MF). The most common modalities are psoralen-UV-A (PUVA) and narrowband UV-B (NBUVB).

Objective

To compare the efficacy and adverse effects of PUVA vs NBUVB in early-stage MF.

Data Sources

A systematic review was performed by searching Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Ovid Medline, PubMed, Cochrane Library, American College of Physicians ACP Journal Club, and Database of Abstracts of Review of Effectiveness from inception to March 30, 2018. UV A, PUVA, mycosis fungoides, Sézary syndrome, cutaneous T-cell lymphoma, UV B, and UVB were used as either key words or MeSH terms.

Study Selection

Studies of cohorts with histologically confirmed early-stage MF, defined as stages IA, IB, and IIA, that compared PUVA vs NBUVB, had at least 10 patients in each comparator group, and reported outcomes of response to therapy. Exclusion criteria were studies with patients with stage IIB or higher MF, pediatric patients, fewer than 10 in each comparator group, noncomparative studies, case reports, and abstract studies.

Data Extraction and Synthesis

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline was followed. Data were pooled using a random-effects model with odds ratio (OR) as effect size.

Main Outcomes and Measures

Main outcomes were complete response rate, partial response rate, disease recurrence, and adverse effects, including erythema, nausea, pruritus, phototoxic effects, dyspepsia, and pain.

Results

Seven studies were included with a total of 778 patients (405 of 724 [55.9%] men; mean age, 52 years); 527 were treated with PUVA and 251 with NBUVB. Most of the included studies were of poor to moderate quality. Any response was found in 479 of the 527 (90.9%) patients treated with PUVA vs 220 of 251 (87.6%) treated with NBUVB (OR, 1.40; 95% CI, 0.84-2.34; P = .20). Complete response was found in 389 of 527 (73.8%) patients who received PUVA vs 156 of 251 (62.2%) who received NBUVB, which was statistically significant (OR, 1.68; 95% CI, 1.02-2.76; P = .04). Partial response was similar (90 of 501 [18.0%] vs 64 of 233 [27.5%]; OR, 0.58; 95% CI, 0.33-1.04; P = .07). No significant difference was found between PUVA and NBUVB in terms of adverse effects of erythema (38 of 527 [7.2%] vs 17 of 251 [6.7%]; P = .54), nausea (10 of 527 [1.9%] vs 3 of 251 [1.2%]; P = .72), pruritus (2 of 527 [0.4%] vs 4 of 251 [1.7%]; P = .26), phototoxic effects (7 of 527 [1.4%] vs 2 of 251 [0.9%]; P = .72), dyspepsia (6 of 527 [1.2%] vs 0 of 251 [0%]; P = .59), or pain (0 of 527 [0%] vs 2 of 251 [0.9%]; P = .50).

Conclusions and Relevance

The findings suggest that PUVA is a potential alternative to NBUVB in the management of early-stage MF. These findings have implications for clinicians involved in the management of early-stage MF.

NBUVB Phototherapy at the Donor Site Can Enhance the Graft Uptake in the Nonhealing of Ulcers of Mycosis Fungoides: A Case Report

Mycosis fungoides is a rare form of non-Hodgkin’s lymphoma, which is formed of mature, skin homing, clonal, malignant T lymphocytes. It can sometimes present with skin ulcers that are difficult to heal because of the presence of large number T lymphocytes and antigen-presenting cells. We present a case of nonhealing ulcers in a patient with mycosis fungoides, which was treated by narrow band ultraviolet B targeted phototherapy followed by split-thickness skin grafting. The graft uptake was well and the donor area also healed without any complications.

UV random laser emission from flexible ZnO-Ag-enriched electrospun cellulose acetate fiber matrix

We report an alternative random laser (RL) architecture based on a flexible and ZnO-enriched cellulose acetate (CA) fiber matrix prepared by electrospinning. The electrospun fibers, mechanically reinforced by polyethylene oxide and impregnated with zinc oxide powder, were applied as an adsorbent surface to incorporate plasmonic centers (silver nanoprisms). The resulting structures - prepared in the absence (CA-ZnO) and in the presence of silver nanoparticles (CA-ZnO-Ag) - were developed to support light excitation, guiding and scattering prototypes of a RL. Both materials were excited by a pulsed (5 Hz, 5 ns) source at 355 nm and their fluorescence emission monitored at 387 nm. The results suggest that the addition of silver nanoprisms to the ZnO- enriched fiber matrix allows large improvement of the RL performance due to the plasmon resonance of the silver nanoprisms, with ~80% reduction in threshold energy. Besides the intensity and spectral analysis, the RL characterization included its spectral and intensity angular dependences. Bending the flexible RL did not affect the spectral characteristics of the device. No degradation was observed in the random laser emission for more than 10,000 shots of the pump laser.

Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis with phototherapy

Psoriasis is a chronic inflammatory disease involving multiple organ systems and affecting approximately 3.2% of the world's population. In this section of the guidelines of care for psoriasis, we will focus the discussion on ultraviolet (UV) light-based therapies, which include narrowband and broadband UVB, UVA in conjunction with photosensitizing agents, targeted UVB treatments such as with an excimer laser, and several other modalities and variations of these core phototherapies, including newer applications of pulsed dye lasers, intense pulse light, and light-emitting electrodes. We will provide an in-depth, evidence-based discussion of efficacy and safety for each treatment modality and provide recommendations and guidance for the use of these therapies alone or in conjunction with other topical and/or systemic psoriasis treatments.

Skin Directed Therapy in Cutaneous T-Cell Lymphoma

Skin directed therapies (SDTs) serve important roles in the treatment of early stage cutaneous T-cell lymphoma (CTCL)/mycosis fungoides (MF), as well as managing symptoms and improving quality of life of all stages. There are now numerous options for topical therapies that demonstrate high response rates, particularly in early/limited MF. Phototherapy retains an important role in treating MF, with increasing data supporting efficacy and long-term safety of both UVB and PUVA as well as some newer/targeted methodologies. Radiation therapy, including localized radiation and total skin electron beam therapy, continues to be a cornerstone of therapy for all stages of MF.

Extra-adrenal glucocorticoid synthesis at epithelial barriers

Epithelial barriers play an important role in the exchange of nutrients, gases, and other signals between our body and the outside world. However, they protect it also from invasion by potential pathogens. Defective epithelial barriers and associated overshooting immune responses are the basis of many different inflammatory disorders of the skin, the lung, and the intestinal mucosa. The anti-inflammatory activity of glucocorticoids has been efficiently used for the treatment of these diseases. Interestingly, epithelia in these tissues are also a rich source of endogenous glucocorticoids, suggesting that local glucocorticoid synthesis is part of a tissue-specific regulatory circuit. In this review, we summarize current knowledge about the extra-adrenal glucocorticoid synthesis at the epithelial barriers of the intestine, lung and the skin, and discuss their relevance in the pathogenesis of inflammatory diseases and as therapeutic targets.

Polymorphic Light Eruption: What's New in Pathogenesis and Management

Polymorphic light eruption is the commonest photosensitive disorder, characterized by an intermittent eruption of non-scarring erythematous papules, vesicles or plaques that develop within hours of ultraviolet radiation exposure of patient skin. Together with the lesions, a terrible itch starts and increases with the spreading of the disease, sometimes aggravated by a sort of burning sensation. Clinical picture and symptoms can improve during the rest of the summer with further solar exposures. In the last years many advances have been performed in the knowledge of its pathogenesis and some news have been proposed as preventive, as well as therapeutic options. All this has been discussed in the current mini review.

Irradiation with 310 nm and 340 nm ultraviolet light-emitting-diodes can improve atopic dermatitis-like skin lesions in NC/Nga mice

Ultraviolet (UV) light produces an immunomodulatory effect on the skin and is widely used for the treatment of chronic inflammatory skin diseases. UV light emitting diodes (UV-LEDs) are a new and promising source of UV radiation. However, their mechanism of action remains largely unknown. In this study, we tested the safety and effectiveness of UV-LED irradiation for the treatment of atopic dermatitis (AD) in an NC/Nga mouse model. Mice were divided into seven groups of eight mice each. Application of Dermatophagoides farinae (Df) extract ointment for four weeks induced AD-like skin lesions. Subsequently, the mice were exposed to UV-LEDs, narrow band UVB, or UVA irradiation three times per week. We assessed the immunosuppressive effects of 310 nm (50 mJ cm-2) and 340 nm (5 J cm-2) UV-LED irradiation. Histological analyses using hematoxylin-eosin, toluidine blue, and immunohistochemical staining were performed. In addition, the serum levels of IgE, inflammatory cytokines and chemokines were measured using enzyme-linked immunosorbent assays (ELISAs). UV-LED irradiation significantly alleviated AD-like skin symptoms, including edema, erythema, dryness, and itching, by modulating Th1 and Th2 responses, transepidermal water loss (TEWL), and scratching behavior in NC/Nga mice. These results suggest that UV-LEDs can improve the treatment of inflammatory skin diseases.

Shedding light on the variability of optical skin properties: finding a path towards more accurate prediction of light propagation in human cutaneous compartments

Finding a path towards a more accurate prediction of light propagation in human skin remains an aspiration of biomedical scientists working on cutaneous applications both for diagnostic and therapeutic reasons. The objective of this study was to investigate variability of the optical properties of human skin compartments reported in literature, to explore the underlying rational of this variability and to propose a dataset of values, to better represent an in vivo case and recommend a solution towards a more accurate prediction of light propagation through cutaneous compartments. To achieve this, we undertook a novel, logical yet simple approach. We first reviewed scientific articles published between 1981 and 2013 that reported on skin optical properties, to reveal the spread in the reported quantitative values. We found variations of up to 100-fold. Then we extracted the most trust-worthy datasets guided by a rule that the spectral properties should reflect the specific biochemical composition of each of the skin layers. This resulted in the narrowing of the spread in the calculated photon densities to 6-fold. We conclude with a recommendation to use the identified most robust datasets when estimating light propagation in human skin using Monte Carlo simulations. Alternatively, otherwise follow our proposed strategy to screen any new datasets to determine their biological relevance.

Physiological Doses of Red Light Induce IL-4 Release in Cocultures between Human Keratinocytes and Immune Cells

Phototherapy is routinely used for the treatment of various skin conditions and targeted therapy of superficial cancers. However, the molecular mechanisms behind their biological effects and the need for efficacy enhancing photosensitizers are not well addressed. Particularly, not much is known about the inherent effect of light from the visible spectrum on cytokine release and its downstream effects in keratinocytes and immune cells located in skin and therefore exposed to light. To address this, we delivered calibrated doses of well-defined light qualities (380 to 660 nm) to cocultures of human keratinocytes and macrophage/dendritic cells in the absence or presence of the commonly used photosensitizer 8-methoxypsoralen (8-MOP). The experiments identified IL-4 as a key effector cytokine released by this coculture model with need for 8-MOP in the UVA₁ /blue (380 nm) and no requirement for photosensitizer in the red light spectrum (627 nm). 3D organotypic skin cultures treated with IL-4 showed thickening of the epidermal layer and delayed differentiation. However unlike IL-4 and UVA₁ /blue light treatment, red light did not reduce the expression of keratinocyte differentiation markers or increase signs of photo-oxidative damage. This supports the application of isolated red light as a possible alternative for photo-immunotherapy without need for additional photosensitizers.

Phototherapy for Pityriasis Lichenoides in the Pediatric Population: A Review of the Published Literature

BACKGROUND

Pityriasis lichenoides (PL) is a dermatologic disorder that manifests in either the acute (pityriasis lichenoides et varioliformis acuta) or the chronic form (pityriasis lichenoides chronica, also known as parapsoriasis chronica). Traditional first-line therapy consists of corticosteroids or antibiotics; however, these treatments are often accompanied with multiple side effects and may be ineffective.

OBJECTIVE

The goal of this study was to review the use of phototherapy for treating PL in the pediatric population.

MATERIALS AND METHODS

We performed a systematic review of the literature in the National Library of Medicine's PubMed database and the SCOPUS database discussing phototherapy for treatment of PL in the pediatric population. The following search terms were used: 'pityriasis lichenoides', 'pityriasis lichenoides chronica', 'pityriasis lichenoides et varioliformis acuta', and 'febrile ulceronecrotic Mucha-Habermann disease'.

RESULTS

The systematic search and screening of articles resulted in 14 articles including a total of 64 patients with PL treated with phototherapy. Three different modalities were utilized, with five studies using broadband ultraviolet B (BB-UVB) radiation, nine studies utilizing narrowband UVB (NB-UVB), and two studies employing psoralen with ultraviolet A (PUVA) therapy. Overall, the use of BB-UVB had an initial clearance rate of 89.6 % with 23.1 % recurrence, whereas NB-UVB cleared 73 % of the lesions with no recurrence, and PUVA therapy initially cleared 83 % of the lesions with 60 % recurrence. The side-effect profiles were similar and revealed limited toxicity.

CONCLUSION

Phototherapy shows promising results and a favorable side-effect profile in the treatment of PL. Ultimately, large randomized controlled trials are needed to determine optimal treatments.

Pityriasis Lichenoides-like Mycosis Fungoides: Clinical and Histologic Features and Response to Phototherapy

Background

Pityriasis lichenoides (PL)-like skin lesions rarely appear as a specific manifestation of mycosis fungoides (MF).

Objective

We investigated the clinicopathological features, immunophenotypes, and treatments of PL-like MF.

Methods

This study included 15 patients with PL-like lesions selected from a population of 316 patients diagnosed with MF at one institution.

Results

The patients were between 4 and 59 years of age. Four patients were older than 20 years of age. All of the patients had early-stage MF. In all patients, the atypical lymphocytic infiltrate had a perivascular distribution with epidermotropism. The CD4/CD8 ratio was <1 in 12 patients. Thirteen patients were treated with either narrowband ultraviolet B (NBUVB) or psoralen+ultraviolet A (PUVA), and all of them had complete responses.

Conclusion

PL-like MF appears to have a favorable prognosis and occurrence of this variant in adults is uncommon. MF should be suspected in the case of a PL-like skin eruption. Therefore, biopsy is required to confirm the diagnosis of PL-like MF, and NBUVB is a clinically effective treatment.

Guidelines for phototherapy of mycosis fungoides and Sézary syndrome: A consensus statement of the United States Cutaneous Lymphoma Consortium

BACKGROUND

Ultraviolet light (UVL) is a long established treatment for mycosis fungoides (MF) and Sézary syndrome (SS), subtypes of cutaneous T-cell lymphoma (CTCL). Treatments have traditionally included broadband, narrowband ultraviolet B light (UVB) and psoralen plus ultraviolet A light photochemotherapy (PUVA), but more recently, treatment options have expanded to include UVA1 and excimer laser. UVL is used either as monotherapy or as an adjuvant to systemic therapy, demonstrating efficacy in many cases that equal or surpass systemic medications. Despite its utility and duration of use, the current practice of using UVL guidelines for psoriasis to treat patients with MF/SS is problematic because the goals of prolonging survival and preventing disease progression are unique to CTCL compared to psoriasis.

OBJECTIVES

We sought to develop separate guidelines for phototherapy for MF/SS for both clinical practice and for clinical trials.

METHODS

Literature review and cutaneous lymphoma expert consensus group recommendations.

RESULTS

This paper reviews the published literature for UVB and UVA/PUVA in MF/SS and suggests practical standardized guidelines for their use.

LIMITATIONS

New standardization of phototherapy.

CONCLUSIONS

These guidelines should allow the comparison of results with phototherapy in MF/SS across different stages of patients, centers, and in combination with other agents in practice and in clinical trials.

A review of the use of tanning beds as a dermatological treatment

Introduction

In-office phototherapy is an effective treatment for many dermatologic conditions, however, many patients are unable to adhere to the rigorous travel and time commitments sometimes needed. Tanning bed facilities are nearly ubiquitous in modern society and could represent a more convenient means to obtain ultraviolet (UV) exposure when office phototherapy is not feasible. The purpose of this study was to review available evidence on the use of tanning facilities as a treatment for dermatologic conditions.

Methods

PubMed was searched on February 2015 for “tanning beds” and “phototherapy”, and with some dermatologic conditions sensitive to UV light, including “psoriasis”, “mycosis fungoides”, “acne”, “atopic dermatitis” and “eczema”. From there, further articles were found using the reference sections of the initial papers. A similar methodology was used with the Google Scholar search engine. Only articles in English and prospective studies were included in this review.

Results

We found studies validating the use of tanning facilities for psoriasis treatment. Use as a treatment option for atopic dermatitis, mycosis fungoides, acne, scleroderma, vitiligo, and pruritus, as well as other UV sensitive dermatoses, may also be beneficial. This study is limited by the lack of double-blind, placebo-controlled trials, long-term follow-up studies, and meta-analyses for tanning facility use in dermatologic phototherapy, and by the lack of standardization of both tanning facilities and exposure dosing.

Conclusion

Unsupervised sun exposure is a standard recommendation for some patients to obtain phototherapy. Selected use of commercial tanning beds in the treatment of dermatologic conditions may be another useful and effective treatment for those patients with an inability to access office-based or home-based phototherapy.

Electronic supplementary material

The online version of this article (doi:10.1007/s13555-015-0071-8) contains supplementary material, which is available to authorized users.

Ultraviolet-B Phototherapy Is Successful in Japanese Patients with Early-Stage Mycosis Fungoides

UVB phototherapy is widely used for the treatment of psoriasis and atopic dermatitis, however, only limited reports evaluate its usefulness in the treatment of mycosis fungoides. We introduced UVB phototherapy to five patients with early-stage mycosis fungoides. All of them were classified as stage IB (erythematous stage), and none had obtained a satisfactory response to other therapies. After initial treatment with UVB phototherapy, all the patients obtained significant improvement in their skin lesions leaving pigmentary changes. After this satisfactory response was achieved, the same dose of UVB was administrated as a maintenance therapy with longer intervals between exposures. Histopathological examination of three patients revealed decreased numbers of inflammatory cells in both the epidermis and the dermis after the treatment. Immunohistochemical study showed that CD1a+/HLA-DR+ dendritic cells were present throughout the lesional epidermis before the treatment. In contrast, after the treatment, the dendritic cells in the epidermis were CD1a+/HLA-DR-. Although it remains unclear why only the expression of HLA-DR antigen was eliminated after treatment, we presume that this loss of HLA-DR antigen expression by epidermal Langerhans cells was, in part, responsible for the improvement of skin lesions. This preliminary study suggests that UVB phototherapy is an effective treatment for patients with early-stage mycosis fungoides.

Photo(chemo)therapy reduces circulating Th17 cells and restores circulating regulatory T cells in psoriasis

Background

Photo(chemo)therapy is widely used to treat psoriasis, the pathogenesis of which might be caused by an imbalance of Th17 cells/regulatory T cells (Treg). In the present study, we evaluated the effects of photo(chemo)therapy on the Th17/Treg balance and Treg function.

Methods

Peripheral blood was obtained from psoriasis patients treated with bath-psoralen ultraviolet A (UVA, n = 50) or narrowband ultraviolet B (UVB, n = 18), and age-matched healthy volunteers (n = 20). CD3⁺CD4⁺IL-17A⁺ or CD4⁺CD25⁺Foxp3⁺cells were analyzed to estimate Th17 or Treg number by fluorescence–activated cell sorting. Moreover, CD4⁺ CD25⁻ T cells from patients treated with PUVA(n = 14) were incubated in CFSE and activated with or without CD4⁺ CD25⁺T cells, and the suppressive function of CD4⁺ CD25⁺T cells were analyzed.

Results

Photo(chemo)therapy significantly reduced Th17 levels from 5.66±3.15% to 2.96±2.89% in patients with increased Th17 (Th17/CD4>3.01% [mean+SD of controls]). In contrast, photo(chemo)therapy significantly increased Treg levels from 2.77±0.75 to 3.40±1.88% in patients with less than 4.07% Treg level, defined as the mean of controls. Furthermore, while Treg suppressed the CD4⁺CD25⁻ T cell proliferation to a greater extent in controls (Treg Functional Ratio 94.4±4.28%) than in patients (70.3±25.1%), PUVA significantly increased Treg Functional Ratio to 88.1±6.47%. Th17 levels in severe patients (>30 PASI) were significantly higher as compared to controls. Th17 levels that were left after treatment in the patients not achieving PASI 50 (3.78±4.18%) were significantly higher than those in the patients achieving PASI 75 (1.83±1.87%). Treg levels in patients achieving PASI 90 (4.89±1.70%) were significantly higher than those in the patients not achieving PASI 90 (3.90±1.66%). Treg levels prior to treatment with Th17 high decreased group (5.16±2.20%) was significantly higher than that with Th17 high increased group (3.33±1.39%).

Conclusion

These findings indicate that Treg is dysfunctional in psoriasis patients, and photochemotherapy restores those dysfunctional Treg. Photo(chemo)therapy resolved the Th17/Treg imbalance in patients with psoriasis.

Beneficial effects of UV radiation other than via vitamin D production

Most of the positive effects of solar radiation are mediated via ultraviolet-B (UVB) induced production of vitamin D in skin. However, several other pathways may exist for the action of ultraviolet (UV) radiation on humans as focused on in this review. One is induction of cosmetic tanning (immediate pigment darkening, persistent pigment darkening and delayed tanning). UVB-induced, delayed tanning (increases melanin in skin after several days), acts as a sunscreen. Several human skin diseases, like psoriasis, vitiligo, atopic dermatitis and localized scleroderma, can be treated with solar radiation (heliotherapy) or artificial UV radiation (phototherapy). UV exposure can suppress the clinical symptoms of multiple sclerosis independently of vitamin D synthesis. Furthermore, UV generates nitric oxide (NO), which may reduce blood pressure and generally improve cardiovascular health. UVA-induced NO may also have antimicrobial effects and furthermore, act as a neurotransmitter. Finally, UV exposure may improve mood through the release of endorphins.

Efficiency of UVA1 therapy in complex treatment of chronic dermatosis

The authors present the results of application of UVA1-therapy in complex treatment of patients with atopic dermatitis, psoriasis and scleroderma. Course of treatment has made 20 procedures of UVA1-therapy with the maximum single dose of irradiation 40 J/ш 2. The general dose of an irradiation 130—400 J/ш 2. Comparison groups received medical therapy with usage of standard doses and reception schemes, and did not differ from the basic groups on age of patients, duration and the disease form. Clinical efficiency estimated on dynamics of indexes SCORAD, PAS! and results of ultrasonic scanning of the scleroderma zones. High efficiency and safety of UVA1-therapy in complex treatment atopic dermatitis, psoriasis and scleroderma is established.

A comparative study on efficacy of UVA1 vs. narrow-band UVB phototherapy in the treatment of vitiligo

BACKGROUND/PURPOSE

Narrow-band ultraviolet B (NB-UVB) is considered the most effective and safe initial treatment for moderate-to-severe vitiligo but phototoxicity and possible carcinogenicity are the reported side effects. Ultraviolet A1 (UVA1) phototherapy has overlapping biological effects to NB-UVB and is relatively free of side effects associated with other phototherapy regimens.

METHODS

Forty patients with vitiligo were included in this prospective, randomized controlled comparative clinical trial. Twenty patients received NB-UVB and 20 received UVA1 three times weekly for 12 weeks. The UVA1 group was divided into two subgroups. Ten patients received moderate and 10 received low dose of UVA1. Serum samples were collected before and after 36 sessions to assess soluble interleukin 2 receptor level. Patients were clinically evaluated before therapy then monthly according to Vitiligo Area Scoring Index (VASI) and Vitiligo European Task Force (VETF) scores. In addition, extent of response was determined by a blinded dermatologist comparing before and after therapy photographs. Pattern of response and side effects were recorded.

RESULTS

NB-UVB was superior to UVA1 with a significant difference in blinded dermatological assessment (P<0.001), percentage change in VASI score (P<0.001) and percentage change in VETF area score (P=0.001). No significant difference in side effects was observed between both groups. Comparing UVA1 subgroups, better response in moderate-dose group was found as regard to percentage change in VASI (P<0.001) and percentage change in VETF area score (P=0.001), while no significant difference was found in blinded dermatological assessment (P=0.121).

CONCLUSION

NB-UVB phototherapy remains to be an effective and safe therapeutic option in vitiligo. Response to UVA1 in vitiligo seems to be dose dependent and seems to be of limited value in treatment of vitiligo as a monotherapy. Further studies combining it with other lines of therapy such as systemic steroids may prove beneficial.

Pruritus in cutaneous T-cell lymphoma: a review

BACKGROUND

Pruritus can be a distressing and even debilitating symptom for patients with cutaneous T-cell lymphoma (CTCL). To date, few studies have evaluated the pathophysiology of this symptom. Because of this, therapy for pruritus in CTCL has mainly relied on those therapies that target and treat the lymphoma. For patients living with CTCL that relapses or becomes refractory to treatment, and who continue to experience severe itch, this lymphoma-targeted treatment may not be enough to combat their pruritus. Therefore, other itch-targeted therapies are needed for use in this disease.

OBJECTIVE

We sought to evaluate the current evidence regarding the mechanism of action and treatments for pruritus associated with CTCL.

METHODS

An explicit and thorough search was restricted to all peer-reviewed literature available through MEDLINE (1950 to September 2011) and PubMed. Search terms used were "pruritus," "cutaneous T-cell lymphoma," "CTCL," "mycosis fungoides," "MF," and "Sézary syndrome." All studies that involved pruritus in CTCL, mycosis fungoides, or Sézary syndrome were evaluated by all 3 authors.

RESULTS

The current literature helps to identify therapies and possible mechanisms for treating patients with CTCL-associated pruritus.

LIMITATION

Most studies were preclinical. Only studies involving mechanisms of action or treatment were included.

CONCLUSION

A guideline is necessary to assist in the treatment of pruritus in CTCL and additional studies are necessary to uncover the exact mechanism or mechanisms of action.

Narrowband ultraviolet B phototherapy of early stage mycosis fungoides in korean patients

Background

Narrowband UVB (NBUVB) is currently used to treat early mycosis fungoides (MF). There are a number of reports on the efficacy and safety of NBUVB in Caucasians, but little data is available for Asians.

Objective

This study was designed to evaluate the effectiveness and safety of NBUVB for early stage MF in Korean patients.

Methods

We enrolled 14 patients (12 men, 2 women; age range, 10~64 years) with clinically and histologically proven MF. Three patients were stage IA, and the others were stage IB. The patients received NBUVB phototherapy three times a week. The starting dose was 70% of the minimal erythema dose and was increased in 20 percent increments if the previous treatment did not cause erythema. Clinical response, total number of treatments, total cumulative dose, duration of remission and side effects were investigated.

Results

Eleven of 14 patients (78.6%) achieved complete remission within a mean of 15.36±5.71 weeks (range, 5~27 weeks), 31.0±7.4 treatments (range, 16~39 treatments) and a mean cumulative UVB dose of 31.31±12.16 J/cm² (range, 11.4~46.8 J/cm²). Three of the 14 patients (21.4%) achieved a partial remission. After discontinuation of treatment, 6 of 11 patients (54.5%) with complete remission relapsed after a mean of 8.5±4.09 months. No serious adverse effects were observed except for hyperpigmentation (7/14, 50%).

Conclusion

Our data suggest that NBUVB therapy is safe and effective for the treatment of early stage MF in Korean patients.

Reversal of atopic dermatitis with narrow-band UVB phototherapy and biomarkers for therapeutic response

BACKGROUND

Atopic dermatitis (AD) is a common inflammatory skin disease exhibiting a predominantly T(H)2/"T22" immune activation and a defective epidermal barrier. Narrow-band UVB (NB-UVB) is considered an efficient treatment for moderate-to-severe AD. In patients with psoriasis, NB-UVB has been found to suppress T(H)1/T(H)17 polarization, with subsequent reversal of epidermal hyperplasia. The immunomodulatory effects of this treatment are largely unknown in patients with AD.

OBJECTIVE

We sought to evaluate the effects of NB-UVB on immune and barrier abnormalities in patients with AD, aiming to establish reversibility of disease and biomarkers of therapeutic response.

METHODS

Twelve patients with moderate-to-severe chronic AD received NB-UVB phototherapy 3 times weekly for up to 12 weeks. Lesional and nonlesional skin biopsy specimens were obtained before and after treatment and evaluated by using gene expression and immunohistochemistry studies.

RESULTS

All patients had at least a 50% reduction in SCORAD index scores with NB-UVB phototherapy. The T(H)2, T22, and T(H)1 immune pathways were suppressed, and measures of epidermal hyperplasia and differentiation normalized. The reversal of disease activity was associated with elimination of inflammatory leukocytes and T(H)2/T22- associated cytokines and chemokines and normalized expression of barrier proteins.

CONCLUSIONS

Our study shows that resolution of clinical disease in patients with chronic AD is accompanied by reversal of both the epidermal defects and the underlying immune activation. We have defined a set of biomarkers of disease response that associate resolved T(H)2 and T22 inflammation in patients with chronic AD with reversal of barrier pathology. By showing reversal of the AD epidermal phenotype with a broad immune-targeted therapy, our data argue against a fixed genetic phenotype.

Therapy of psoriasis in childhood and adolescence - a German expert consensus

Psoriasis of childhood shows an annual prevalence of 0.71 % and accordingly has to be regarded as a frequent chronic inflammatory skin disorder of this age. The impact on the quality of life as well as development of the afflicted children and their parents is evident. On the other side, therapy is demanding with regard to the specific juvenile metabolism, physical development and skin penetration of topical drugs. Long-term treatment at an early age has to be critically judged regarding the chronicity of the disease. Topical corticosteroids, alternatively dithranol may be used first-line, followed by vitamin D derivatives. A combination with UV-light, preferably UV-B, has to be decided on an individual basis. Systemic treatment may be initiated in recalcitrant disease with methotrexate and cyclosporine where long-term experience is available from juvenile rheumatology and transplantation medicine. Alternatively fumaric acid esters or retinoids are available. Rehabilitation procedures will help the children and their parents to cope with the disease and its treatment. The different treatment options are presented here as a German expert consensus, as clinical studies are hardly available and only a few therapeutics are licensed for this age. In any case the therapy has to be individually planned and decided together with the patients and their parents to gain maximal safety, comfort and success.

UV-based therapy and vitamin D

The ultraviolet (UV) light spectrum has long been known to induce biologic effect on the skin. For a large number of cutaneous disorders, phototherapy and photochemotherapy are effective therapeutic options with excellent safety profiles and well-documented side effects. Despite their ease of administration and benefits, phototherapeutic treatment modalities require appropriate space for the equipment, trained staff, and patient education prior to initiating treatment. However, when the initial barriers to treatment can be overcome, UV therapy can offer patients significant relief from their cutaneous disease. Furthermore, UVB-based phototherapy can produce significant alteration to vitamin D levels. With the recent research implicating association of low vitamin D levels with a variety of health conditions, whether patients receiving phototherapy or, more specifically, those getting vitamin D supplement may be protected from these diseases remains to be established.

Efficiency of using a narrow-band 311 nm mid-wavelength ultraviolet therapy at atopic dermatitis in children

The article presents the results of using a narrow-band mid-wavelength ultraviolet therapy (311 nm) in 79 children suffering from with atopic dermatitis. The course of treatment comprised 15 to 20 sessions of ultraviolet therapy with the maximal dose of irradiation being not more than 0.15 J/cm2. The control group (n=35) received traditional therapeutic treatment with the use of standard schemes of dosing and drug administration, and did not differ from the main group of patients in age, duration or form of the disease. Clinical efficacy of the therapy was estimated according to the SCORAD index, Dermatological Index of the Symptom Scale and Children's Dermatology Life Quality Index. The efficacy of the narrow-band mid-wavelength ultraviolet therapy (311 nm) turned out to be very high, which is confirmed by earlier reduction of clinical symptoms among patients from this group than in the control group. The latter fact was also confirmed by the reduction of absolute values of the SCORAD index and Dermatological Index of the Symptom Scale (p

Efficacy of narrowband UVB vs. PUVA in patients with early-stage mycosis fungoides

INTRODUCTION

Mycosis fungoides (MF) is a non-Hodgkin's T-cell lymphoma of the skin that often begins as limited patches and plaques with slow progression to systemic involvement. Narrowband ultraviolet (UV) B therapy has been proven to be an effective short-term treatment modality for clearing patch-stage MF. The effect of psoralen plus long-wave ultraviolet A (PUVA) in the treatment of patch- and plaque-type MF has also been thoroughly documented.

OBJECTIVES

The purpose of this study was to compare the efficacy and safety of narrowband UVB and PUVA in patients with early-stage MF.

METHODS

We analysed the response to treatment, relapse-free survival and irradiation dose in 114 patients with histologically confirmed early-stage MF (stage IA, IB and IIA).

RESULTS

A total of 95 patients were treated with PUVA (83.3%) and 19 with narrowband UVB (16.7%). With PUVA, 59 patients (62.1%) had a complete response (CR), 24 (25.3%) had a partial response (PR) and 12 (12.6%) had a failed response. Narrowband UVB led to CR in 12 (68.4%) patients, PR in 5 (26.3%) patients and a failed response in 1 (5.3%) patient. There were no differences in terms of time to relapse between patients treated with PUVA and those treated with narrowband UVB (11.5 vs. 14.0 months respectively; P = 0.816). No major adverse reactions were attributed to the treatment.

CONCLUSIONS

Our results confirm that phototherapy is a safe, effective and well-tolerated, first-line therapy in patients with early-stage cutaneous T-cell lymphoma, with prolonged disease-free remissions being achieved. It suggests that narrowband UVB is at least as effective as PUVA for treatment of early-stage MF.

UVA-induced calcium oscillations in rat mast cells

UVA is a major bio-active component in solar irradiation, and is shown to have immunomodulatory and anti-inflammatory effects. The detailed molecular mechanism of UVA action in regard to calcium signaling in mast cells, however, is not fully understood. In this study, it was found that UVA induced ROS formation and cytosolic calcium oscillations in individual rat mast cells. Exogenously added H2O2 and hypoxanthine/xanthine oxidase (HX/XOD) mimicked UVA effects on cytosolic calcium increases. Regular calcium oscillation induced by UVA irradiation was inhibited completely by the phosphatidylinositol-specific phospholipase C inhibitor U73122, but U73343 was without effect. Tetrandrine, a calcium entry blocker, or calcium-free buffer abolished UVA-induced calcium oscillations. L-type calcium channel blocker nifedipine and stores-operated calcium channel blocker SK&F96365 had no such inhibitory effect. ROS induction by UVA was abolished after pre-incubation with anti-oxidant NAC or with NAD(P)H oxidase inhibitor DPI; such treatment also made UVA-induced calcium oscillation to disappear. UVA irradiation did not increase mast cell diameter, but it made mast cell structure more granular. Spectral confocal imaging revealed that the emission spectrum of the endogenous fluorophore in single mast cell contained a sizable peak which corresponded to that of NAD(P)H. Taken together, these data suggest that UVA in rat mast cells could activate NAD(P)H oxidase, to produce ROS, which in turn activates phospholipase C signaling, to trigger regular cytosolic calcium oscillation.

High-dose ultraviolet light exposure reduces scar hypertrophy in a rabbit ear model

BACKGROUND

The effects of ultraviolet light exposure on scar pigmentation are well documented. There is a commonly held belief among physicians that sun exposure may also worsen the appearance of fresh scars and result in excess collagen deposition. However, few studies have documented a relationship between ultraviolet light exposure and hypertrophic scarring. This study sought to evaluate the effect of ultraviolet light exposure on scar hypertrophy in an established rabbit model of cutaneous scarring.

METHODS

Four 7-mm ulcers were created on the ventral ears of eight rabbits. Starting on postoperative day 15, half of the wounds were exposed to ultraviolet-B radiation daily for either 7 or 14 days. Ultraviolet-B-exposed (n = 16) and control (n = 16) scars were harvested on postoperative day 32 for histologic and reverse-transcriptase polymerase chain reaction analysis.

RESULTS

Exposure to ultraviolet-B radiation for 7 or 14 days was associated with a 52 percent (p < 0.01) or 74 percent (p < 0.05) reduction in scar volume, respectively, compared with controls. In wounds subjected to ultraviolet-B radiation for 14 days, collagen type I-alpha2 mRNA expression was 29 percent lower than in controls (p < 0.05). There was no difference in the mRNA expression of transforming growth factor-beta1.

CONCLUSION

: These short-term observations demonstrate that ultraviolet-B radiation exposure reduces scar hypertrophy in this clinically relevant animal model. A reduction in collagen production or increase in collagen breakdown may account for this result. However, sunscreen should still be used as primary protection when skin is exposed to direct sunlight.

Narrowband ultraviolet B radiation suppresses contact hypersensitivity

BACKGROUND/PURPOSE

A main mechanism responsible for the efficacy of narrowband ultraviolet (UV)B is thought to be the induction of apoptosis in pathogenetically relevant cells. Narrowband UVB therapy, however, generally induces a relatively long remission period. Recently, evidence that UVB radiation induces regulatory T (Treg) cells was reported. Based on these findings, we examined whether narrowband UVB suppresses contact hypersensitivity (CHS) by inducing Treg cells.

METHODS

The shaved abdomens of C3H/HeN mice were irradiated with broadband or narrowband UVB. CHS was defined as an ear-swelling response. To examine whether tolerance can be induced by adoptive transfer, lymph node cells from UVB-irradiated mice were injected into naïve mice before sensitization and CHS challenge.

RESULTS

Narrowband UVB exposure dose dependently suppressed CHS. Significant suppression was observed at doses between 1000 and 3000 mJ/cm(2) (P<0.05). The suppressive effect achieved with 1000 mJ/cm(2) narrowband UVB was very similar to the effect achieved with 100 mJ/cm(2) broadband UVB. The suppressive effects on CHS were transferred to naïve mice by the injection of lymph node cells from tolerant mice.

CONCLUSION

Narrowband UVB induced local and systemic suppression of CHS. In addition, narrowband UVB induces tolerance to CHS and the suppressive effects were transferable to naïve mice.