Determination of the Minimal Erythema Dose and Colorimetric Measurements as Indicators of Skin Sensitivity to UV-B Radiation¶

Validation of a novel method of ultraviolet-induced cutaneous inflammation and its associations with anhedonia

Affective immunology of the skin is a growing area; however, established protocols for measuring individual differences in cutaneous inflammation are lacking. To address this, we present a preliminary validation of Precision Implementation of Minimal Erythema Dose (PI-MED) testing as a method for measuring cutaneous inflammation. PI-MED is a recently adapted protocol, optimized for reproducibility and individual differences research, that uses ultraviolet (UV) light to evoke cutaneous erythema, or inflammatory skin reddening. PI-MED's novel UV dosage schedule produces standardized erythema responses across different skin pigmentation types and shows strong internal consistency within person and good test-retest reliability across 8-10 weeks. In line with predictions, increased PI-MED erythema was associated with heightened anhedonia, across several measures, beyond influences of non-affective covariates. While future work should further refine the dosage schedule for the lightest and darkest skin types, overall, evidence supports PI-MED as a protocol for inducing and measuring individual differences in cutaneous inflammation. Further, PI-MED-induced erythema can expand psychoneuroimmunology research by offering a complementary assessment for general inflammatory tone. This work adds to a growing body of evidence demonstrating a distinct relationship between inflammation and anhedonia.

Activation of the JNKs/ATM-p53 axis is indispensable for the cytoprotection of dermal fibroblasts exposed to UVB radiation

Although UVB radiation is mainly absorbed by the epidermis, ~5-10% of its photons reach and affect the upper part of the dermis. Physiologically relevant UVB doses, able to provoke erythema, induce apoptosis in human dermal fibroblasts in vitro, as well as in the dermis of SKH-1 mice. Given the sparse and even contradictory existing information on the effect of UVB radiation on dermal fibroblasts' viability, aim of this work was to unravel the crucial signaling pathways regulating the survival of UVB-treated human dermal fibroblasts. We found that UVB radiation immediately stimulates the phosphorylation of MAPK family members, as well as Akt, and is genotoxic leading to the delayed ATM-p53 axis activation. Akt phosphorylation after UVB radiation is EGFR-mediated and EGFR inhibition leads to a further decrease of viability, while the Akt activator SC79 rescues fibroblasts to an extent by a mechanism involving Nrf2 activation. The known Nrf2 activator sulforaphane also exerts a partial protective effect, although by acting in a distinct mechanism from SC79. On the other hand, inhibition of JNKs or of the ATM-p53 axis leads to a complete loss of viability after UVB irradiation. Interestingly, JNKs activation is necessary for p53 phosphorylation, while the ATM-p53 pathway is required for the long-term activation of JNKs and Akt, reassuring the protection from UVB. Although UVB radiation results in intense and prolonged increase of intracellular ROS levels, classical anti-oxidants, such as Trolox, are unable to affect Akt, JNKs, or p53 phosphorylation and to reverse the loss of fibroblasts' viability. Collectively, here we provide evidence that the main viability-regulating UVB-triggered biochemical pathways act synergistically towards the protection of human dermal fibroblasts, with EGFR/Akt and Nrf2 serving as auxiliary anti-apoptotic machineries, while JNKs/ATM-p53 activation and interplay being overriding and indispensable for the perpetuation of cellular defense and the maintenance of cell viability.

Minimal Erythema Dose: Correlation with Fitzpatrick Skin Type and Concordance Between Methods of Erythema Assessment in a Patient Sample in Colombia

BACKGROUND AND OBJECTIVE

The minimal erythema dose (MED), an essential measurement in studies of skin photosensitivity, requires establishing MED values for specific populations, given genetic variation. Different ways to assess erythema are also relevant. We aimed to determine MED values in a sample of Colombian patients and correlations between MED and Fitzpatrick skin type. We also studied concordance correlation between MEDs and two alternative ways to assess erythema.

PATIENTS AND METHODS

Cross-sectional study of 113 individuals in Bogotá, Colombia. We used a solar simulator to measure UV-A radiation and combined UV-A and UV-B (UVA+UVB) radiation, o se podría suprimir este término porque UVA y UVB son términos conocidos for MED calculation. Narrowband UV-B (NBUVB) radiation was measured in a phototherapy cabin. Erythema was assessed visually and with a Mexameter MX 18 device.

RESULTS

The median MEDs of UVA+UVB radiation were 22mJ/cm² for Fitzpatrick skin typesI andII, and 33 and 43mJ/cm², respectively, for typesIII andIV. The MEDs of UV-A radiation were 22, 42, 86, and 100J/cm² for typesI, II, III, andIV, respectively. The MEDs of NBUVB light were 390, 550, 770, and 885mJ/cm² for the 4 skin types. The correlation between MEDs and skin types ranged from 0.5 to 0.69. Lin's concordance correlation coefficients between visual and Mexameter assessments of erythema were greater than 0.8 in all cases.

CONCLUSION

This study allowed us to understand MED values for UV-A, UVA+UVB, and NBUVB according to different skin types in the Colombian population. Concordance correlation coefficients between the different methods of erythema assessment were very good. Correlations between MEDs and skin types were moderate to good.

Skin typing: Fitzpatrick grading and others

Skin phototyping refers to a skin classification scheme based on how the skin responds to sun exposure. The Fitzpatrick classification is the most widely accepted method of skin phototyping, based on a person's tendency to sunburn and ability to tan. Apart from estimating the initial therapeutic dose of UV light, skin phototyping is also useful in predicting the risk of photodamage and skin cancer and the outcome of esthetic procedures. Techniques to type the skin objectively have been developed to address the deficiencies associated with the subjective Fitzpatrick classification. Some skin typing systems have been proposed specifically to predict the response of skin to cosmetic procedures such as chemical peeling and laser resurfacing. We discuss the concept of skin type and its relation to skin color, as well as critically appraising the various available methods of skin typing.

Clinical and Biological Characterization of Skin Pigmentation Diversity and Its Consequences on UV Impact

Skin color diversity is the most variable and noticeable phenotypic trait in humans resulting from constitutive pigmentation variability. This paper will review the characterization of skin pigmentation diversity with a focus on the most recent data on the genetic basis of skin pigmentation, and the various methodologies for skin color assessment. Then, melanocyte activity and amount, type and distribution of melanins, which are the main drivers for skin pigmentation, are described. Paracrine regulators of melanocyte microenvironment are also discussed. Skin response to sun exposure is also highly dependent on color diversity. Thus, sensitivity to solar wavelengths is examined in terms of acute effects such as sunburn/erythema or induced-pigmentation but also long-term consequences such as skin cancers, photoageing and pigmentary disorders. More pronounced sun-sensitivity in lighter or darker skin types depending on the detrimental effects and involved wavelengths is reviewed.

A Wearable Colorimetric Dosimeter to Monitor Sunlight Exposure

The personal ultraviolet (UV) dosimeter is a useful measurement tool to prevent UV induced dermal damages; however, conventional digital dosimeters are either bulky or require external power sources. Here, a wearable, colorimetric UV film dosimeter that provides color transition, from purple to transparent, is reported to indicate the UV dose. The film dosimeter is made of a purple photodegradable dye ((2Z,6Z)-2,6-bis(2-(2,6-diphenyl-4H-thiopyran-4-ylidene)ethylidene)cyclohexanone or DTEC) blended in low density polyethylene film. The DTEC film discolored 3.3 times more under the exposure of UV light (302 nm) than visible light (543 nm), and a UV bandpass filter is developed to increase this selectivity to UV light. The DTEC film completely discolors to transparency in 2 h under an AM 1.5 solar simulator, suggesting the potential as an indicator for individuals with types I-VI skin to predict interventions to avoid sunburn. Finally, the DTEC film is integrated with the UV bandpass filter on a wristband to function as a wearable dosimeter for low cost and convenient monitoring of sunlight exposure.

Fibroblasts potentiate melanoma cells in vitro invasiveness induced by UV-irradiated keratinocytes

Melanoma represents a malignant disease with steadily increasing incidence. UV-irradiation is a recognized key factor in melanoma initiation. Therefore, the efficient prevention of UV tissue damage bears a critical potential for melanoma prevention. In this study, we tested the effect of UV irradiation of normal keratinocytes and their consequent interaction with normal and cancer-associated fibroblasts isolated from melanoma, respectively. Using this model of UV influenced microenvironment, we measured melanoma cell migration in 3-D collagen gels. These interactions were studied using DNA microarray technology, immunofluorescence staining, single cell electrophoresis assay, viability (dead/life) cell detection methods, and migration analysis. We observed that three 10 mJ/cm² fractions at equal intervals over 72 h applied on keratinocytes lead to a 50% increase (p < 0.05) in in vitro invasion of melanoma cells. The introduction cancer-associated fibroblasts to such model further significantly stimulated melanoma cells in vitro invasiveness to a higher extent than normal fibroblasts. A panel of candidate gene products responsible for facilitation of melanoma cells invasion was defined with emphasis on IL-6, IL-8, and CXCL-1. In conclusion, this study demonstrates a synergistic effect between cancer microenvironment and UV irradiation in melanoma invasiveness under in vitro condition.

Investigation of suitable starting doses of narrowband UVB in Asian vitiligo patients: a pilot study

BACKGROUND

Phototherapy is the preferred treatment modality for active and generalized vitiligo. One of the widely accepted consensus on starting dose of phototherapy is using a uniform dose of 280 mJ/cm² regardless of patients' Fitzpatrick skin phototype (SPT). However, in many clinical experiences with Asian vitiligo patients, the protocol seems suboptimal.

OBJECTIVE

To gather more evidence on establishing a higher starting dosage for Asian vitiligo patients undergoing phototherapy.

METHODS

We enrolled generalized vitiligo patients with lesions sized adequate enough for phototest. Minimal erythema dose (MED) of vitiligo lesion and non-lesion was measured along with melanin index (MI).

RESULTS

Relatively, a wide range of MED and MI was observed even among patients with similar SPT. The range of MED for lesional skin was 300-700 mJ/cm² and the MED for non-lesion was 500-800 mJ/cm² . Correlation was noted between lesional MED and non-lesional MI (Spearman correlation, ρ = 0.664 [P < 0.036]) and mean lesional MED was approximately 65% of mean non-lesional MED.

CONCLUSION

Results from phototest and tolerability of patients to doses higher than 280 mJ/cm² may indicate that higher starting doses might be appropriate for Asian vitiligo patients.

Comparison of the acute ultraviolet photoresponse in congenic albino hairless C57BL/6J mice relative to outbred SKH1 hairless mice

Hairless albino Crl:SKH1-Hr(hr) mice are commonly utilized for studies in which hair or pigmentation would introduce an impediment to observational studies. Being an outbred strain, the SKH1 model suffers from key limitations that are not seen with congenic mouse strains. Inbred and congenic C57BL/6J mice are commonly utilized for modified genetic mouse models. We compare the acute UV-induced photoresponse between outbred SKH1 mice and an immune competent, hairless, albino C57BL/6J congenic mouse line [B6.Cg-Tyr(c-2J) Hr(hr) /J]. Histologically, B6.Cg-Tyr(c-2J) Hr(hr) /J skin is indistinguishable from that of SKH1 mice. The skin of both SKH1 and B6.Cg-Tyr(c-2J) Hr(hr) /J mice exhibited a reduction in hypodermal adipose tissue, the presence of utricles and dermal cystic structures, the presence of dermal granulomas and epidermal thickening. In response to a single 1500 J/m(2) ultraviolet B dose, the oedema and apoptotic responses were equivalent in both mouse strains. However, B6.Cg-Tyr(c-2J) Hr(hr) /J mice exhibited a more robust delayed sunburn reaction, with an increase in epidermal erosion, scab formation and myeloperoxidase activity relative to SKH1 mice. Compared with SKH1 mice, B6.Cg-Tyr(c-2J) Hr(hr) /J also exhibited an aberrant proliferative response to this single UV exposure. Epidermal Ki67 immunopositivity was significantly suppressed in B6.Cg-Tyr(c-2J) Hr(hr) /J mice at 24 h post-UV. A smaller non-significant reduction in Ki67 labelling was observed in SKH1 mice. Finally, at 72 h post-UV, SKH1 mice, but not B6.Cg-Tyr(c-2J) Hr(hr) /J mice, exhibited a significant increase in Ki67 immunolabelling relative to non-irradiated controls. Thus, B6.Cg-Tyr(c-2J) Hr(hr) /J mice are suitable for photobiology experiments.

Pharmacokinetic profile of methotrexate in psoriatic skin via the oral or subcutaneous route using dermal microdialysis showing higher methotrexate bioavailability in psoriasis plaques than in non-lesional skin

AIMS

The aim of this pilot study was to use microdialysis to evaluate levels of Methotrexate (MTX) directly in psoriatic skin following oral or subcutaneous administration of MTX to elaborate a complete pharmacokinetic profile within the dermal skin.

METHODS

Six patients with chronic plaque psoriasis on the arm undergoing treatment with MTX were included in a mono-centre clinical trial. Patients were under treatment with p.o. or s.c. MTX (7.5 and 15 mg) for at least 3 months. Interstitial fluid was collected ex vivo via dermal microdialysis from lesional or non-lesional skin and via intravenous microdialysis as well as blood serum every hour up to 10 h after methotrexate administration every hour. MTX was analysed via liquid chromatography.

RESULTS

The area under the curve (AUC) of methotrexate from peripheral blood was up to four times higher than from microdiaylsis, which detection of free unbound MTX. The AUC from dialysates in psoriatic lesional skin was higher than in non-lesional psoriatic skin, and the AUC levels from i.v. microdialysis were non-significantly higher than those from lesional psoriatic skin. Pharmacokinetic profiles were individually quite different and did not primarily depend on the dose or the means (p.o. vs. s.c.) in which it was administered.

CONCLUSION

Dermal microdialysis is a valid tool to evaluate levels of methotrexate in the skin of psoriasis patients. Drug levels and bioavailability of methotrexate were higher in lesional than non-lesional psoriatic skin. The individual AUC of MTX was not primarily dependent on the route or dose of administration.

Identification of a possible susceptibility locus for UVB-induced skin tanning phenotype in Korean females using genomewide association study

A two-stage genomewide association (GWA) analysis was conducted to investigate the genetic factors influencing ultraviolet (UV)-induced skin pigmentation in Korean females after UV exposure. Previously, a GWA study evaluating ~500 000 single nucleotide polymorphisms (SNPs) in 99 Korean females identified eight SNPs that were highly associated with tanning ability. To confirm these associations, we genotyped the SNPs in an independent replication study (112 Korean females). We found that a novel SNP in the intron of the WW domain-containing oxidoreductase (WWOX) gene yielded significant replicated associations with skin tanning ability (P-value = 1.16 × 10(-4) ). To understand the functional consequences of this locus located in the non-coding region, we investigated the role of WWOX in human melanocytes using a recombinant adenovirus expressing a microRNA specific for WWOX. Inhibition of WWOX expression significantly increased the expression and activity of tyrosinase in human melanocytes. Taken together, our results suggest that genetic variants in the intronic region of WWOX could be determinants in the UV-induced tanning ability of Korean females. WWOX represents a new candidate gene to evaluate the molecular basis of the UV-induced tanning ability in individuals.

Ultraviolet Protection by Fabric Engineering

Background. The increasing emission of greenhouse gases has evoked the human being to save the ozone layer and minimize the risk of ultraviolet radiation (UVR). Various fabric structures have been explored to achieve desired ultraviolet protection factor (UPF) in various situations. Objective. In this study, the effect of various filament configurations like twisted, flat, intermingled, and textured in multifilament yarns on fabric in different combinations is assessed in order to engineer a fabric of better ultraviolet protection factor (UPF). Methods. In order to engineer a fabric having optimum UV protection with sufficient comfort level in multifilament woven fabrics, four different yarn configurations, intermingled, textured, twisted, and flat, were used to develop twelve different fabric samples. The most UV absorbing and most demanding fibre polyethylene terephthalate (PET) was considered in different filament configuration. Results. The combinations of intermingled warp with flat, intermingled, and textured weft provided excellent UVR protection comparatively at about 22.5 mg/cm2 fabric areal density. The presence of twisted yarn reduced the UV protection due to enhanced openness in fabric structure. Conclusion. The appropriate combination of warp and weft threads of different configuration should be selected judiciously in order to extract maximum UV protection and wear comfort attributes in multifilament woven PET fabrics.

Non-invasive diffuse reflectance measurements of cutaneous melanin content can predict human sensitivity to ultraviolet radiation

The diversity of human skin phenotypes and the ubiquitous exposure to ultraviolet radiation (UVR) underscore the need for a non-invasive tool to predict an individual's UVR sensitivity. We analysed correlations between UVR sensitivity, melanin content, diffuse reflectance spectroscopy (DR) and UVR-induced DNA damage in the skin of subjects from three racial/ethnic groups: Asian, black or African American and White. UVR sensitivity was determined by evaluating each subject's response to one minimal erythemal dose (MED) of UVR one day after the exposure. Melanin content was measured using DR and by densitometric analysis of Fontana-Masson staining (FM) in skin biopsies taken from unexposed areas. An individual's UVR sensitivity based on MED was highly correlated with melanin content measured by DR and by FM. Therefore, a predictive model for the non-invasive determination of UVR sensitivity using DR was developed. The MED precision was further improved when we took race/ethnicity into consideration. The use of DR serves as a tool for predicting UVR sensitivity in humans that should be invaluable for determining appropriate UVR doses for therapeutic, diagnostic and/or cosmetic devices.

Relationship between skin parameters (darkness or thickness) and photoreaction of Chinese Han skin

BACKGROUND

Skin pigmentation and the stratum corneum are the two primary natural factors that protect against UV damage. Although several classification systems exist to quantify the ability of the skin to protect itself from damaging UV radiation, few reports have assessed skin parameters and photoreaction in persons of Han Chinese descent.

AIMS

To understand the relationship between skin darkness, skin thickness, and photoreaction in Chinese Han subjects.

METHODS

Thirty-one subjects were exposed to UVA and UVB. Minimal persistent pigment darkening dose (MPPD) and minimal erythema dose (MED) were obtained. Before the UV irradiation, the test sites were measured by the Mexameter MX 16, Chromameter CR400, and Skin B-ultrasonic to determine skin color and thickness>. Using the ratio of J(MPPD)/J(MED), we classified the subjects into four energy skin phototypes (ESPTs) and the skin parameters for each of these groups were analyzed.

RESULTS

Skin color and skin thickness were significantly different among the ESPTs. There was also a significant positive correlation between skin group and the skin color and thickness parameters (b*, melanin index [MI], thickness). As the ESPTs increased from ESPT A to ESPT D, the mean dose to achieve MED increased, while the MPPD decreased.

CONCLUSION

As the ESPTs increased from type A to type D, there was a proclivity to tan rather than burn. Similarly, the skin became darker and thicker as the phototype increased from A to D.

Preliminary assessment of the risks associated with solar ultraviolet-A exposure

An approach is proposed to assess the periods of human skin exposure to solar ultraviolet-A (UV-A, 315-400 nm) irradiance in natural conditions that are able to yield doses found to trigger carcinogenesis in laboratory experiments. Weighting functions, adopted to perform such estimate are constructed, allowing for a comparison between environmental and laboratory doses. Furthermore, the impact of stratum corneum (SC) thickness on the studied environmental doses was investigated. Based on laboratory studies, it was found that exposure periods of less than a month, at mid-latitudes, could provide irradiance doses capable of causing tumor formation. The duration of these exposure periods closely depends on the exposure regime, atmospheric conditions and SC thickness. It is believed that the presented evaluations could provide a useful preliminary estimation of the risk associated with environmental UV-A exposure prior to the formulation of the corresponding action spectra and determination of the threshold doses.

Adolescent attitudes towards tanning: does age matter?

Adolescents seem to be obsessed with tanning. One third of both adolescents and adults report sunbathing. On average, about 20% of adolescents report ever-using of artificial UV tanning devices with 15% currently using them. Tanning attitudes appear similar for adolescents and adults. The top three reasons for tanning included beliefs that a tan makes them more comfortable socializing with friends, looks better and is attractive. The top reason for using artificial UV tanning devices is also aesthetics, followed by relaxation. Other reasons for using artificial UV tanning devices include vacation preparation and to gain a protective base. Attitudes related to appearance that result in more frequent tanning may be difficult to change.

Radiation-Inducedin VitroPhototoxic Potential of Some Fluoroquinolones

Photosensitizing drugs that can damage cellular biomolecules is a matter of concern. Lomefloxacin, norfloxacin, ofloxacin, and enoxacin (broad-spectrum antibiotics of fluoroquinolone group) are used for the treatment of Gram-positive and Gram-negative bacterial infections. Phototoxicity and possible mechanism of their action was assessed under the exposure of ambient levels of UV-A, UV-B, and sunlight at a concentration generally used in the treatment of various diseases. Singlet oxygen (1O2), superoxide anion radical (O2.-) generation, DNA damage, and lipid peroxidation in human blood were studied. All the fluoroquinolones tested in this study produced 1O2 and O2.- under exposure to UV-A, UV-B, and sunlight depending on the concentrations (0 to 60 microg/mL) of the drugs. Enoxacin showed a higher yield of 1O2 and O2.- than other drugs. These materials also degraded deoxyguanosine and induced lipid peroxidation in vitro under exposure to UV-A, UV-B, and sunlight (depending on the dose of radiation). The formation of the reactive oxygen species (ROS) by the photoexcited drugs may be considered as a possible mechanism of their action.

Absorption spectra of human skin in vivo in the ultraviolet wavelength range measured by optoacoustics

Knowledge of the optical properties of human skin in the ultraviolet range is fundamental for photobiologic research. However, optical properties of human skin in the ultraviolet spectral range have so far mainly been measured ex vivo. We have determined the absorption spectra of human skin in vivo in the wavelength range from 290 to 341 nm in 3 nm steps using laser optoacoustics. In this technique, optical properties are derived from the pressure profile generated by absorbed light energy in the sample. In a study on 20 subjects belonging to phototypes I-IV, we studied the optical properties at the volar and dorsal aspect of the forearm as well as on the thenar. Analysis of the measured absorption spectra shows that comparable skin areas-like different sides of the forearm-have qualitatively similar optical characteristics. Still, the optical properties may vary substantially within the same area, probably due to the skin structure and inhomogeneities. Comparison of the spectra from different skin sites indicates that the spectral characteristics of the stratum corneum and its chromophores play an important role for the optical properties of human skin in vivo in the ultraviolet B range.

Fototerapia: aplicações clínicas

Fototerapia é a modalidade terapêutica que aplica exposições repetidas e controladas de radiação ultravioleta para alterar a fisiologia cutânea de modo a induzir a regressão ou controlar a evolução de diversas dermatoses. Este texto apresenta uma visão geral das práticas correntes que utilizam a radiação ultravioleta isolada ou em combinação com fotossensibilizantes ou outras medicações. Serão ainda discutidos os mecanismos de ação de cada modalidade, as indicações mais aceitas, seus esquemas de prescrição, efeitos adversos e cuidados especiais.

Relationship between skin response to ultraviolet exposure and skin color type

Sun exposure is responsible for detrimental damage ranging from sunburn to photoaging and skin cancer. This damage is likely to be influenced by constitutive pigmentation. The relationship between ultraviolet (UV) sensitivity and skin color type was analyzed on 42 ex vivo skin samples objectively classified from light to dark skin, based on their values of individual typology angle (ITA) determined by colorimetric parameters. The biologically efficient dose (BED) was determined for each sample by quantifying sunburn cells after exposure to increasing doses of UV solar-simulated radiation. Typical UV-induced biologic markers, other than erythema, such as DNA damage, apoptosis and p53 accumulation, were analyzed. A statistically significant correlation was found between ITA and BED and, ITA and DNA damage. Interestingly, DNA lesions were distributed throughout the whole epidermal layers and the uppermost dermal cells in light, intermediate and tanned skin while they were restricted to suprabasal epidermal layers in brown or dark skin. Our data support, at the cellular level, the relationship between UV sensitivity and skin color type. They emphasize the impact of DNA damage accumulation in basal layer in relation to the prevalence of skin cancer.

Validation of a melasma quality of life questionnaire for Brazilian Portuguese language: the MelasQoL-BP study and improvement of QoL of melasma patients after triple combination therapy

BACKGROUND

Pigmentation disorders, such as melasma, greatly influence the quality of life (QoL) of affected individuals who usually consider the disorder to be more severe than the objective clinical scores. Several instruments have been successfully developed to evaluate QoL. However, they must be adapted to the target population in terms of language and cultural diversity. The first, specific QoL questionnaire for melasma (MelasQoL) was developed for English speaking patients.

OBJECTIVES

To validate the Brazilian Portuguese version of the MelasQoL evaluation questionnaire for patients with melasma (MelasQoL-BP) and to assess the impact of treatment with a triple combination cream (hydroquinone, fluocinolone acetonide and tretinoin) on the QoL of patients with moderate-to-severe melasma.

METHODS AND RESULTS

Three hundred individuals from the five Brazilian geographic regions took part in this multicentre study. Their mean age was 42 years and skin phototype distribution was: type II 7.0% of patients, III 23.7%, IV 42.7% and V 22.7%. Melasma Area and Severity Index (MASI), MelasQoL-BP and the short version of the QoL assessment instrument from the World Health Organization (WHOQOL-BREF) were used to assess melasma severity and QoL at baseline. MelasQoL-BP was previously translated and culturally adapted from the English version, with participation of the authors and according to the standards of the World Health Organization (WHO). From the original sample, we randomized150 volunteers to treat melasma and repeated the evaluation after 8 weeks. The analysis of the MelasQoL-BP baseline answers demonstrated an important impact of the disease on skin appearance (65% of patients were bothered all the time or most of the time), frustration (55%), embarrassment (57%) and influence of the disease on interpersonal relationships (42%). Forty-three per cent of patients felt not attractive or even dirty due to their skin condition. MelasQoL-BP results showed significant internal consistency (Cronbach's alpha coefficient 0.919; P < 0.001) and good correlation with MASI scores. After treatment, the global assessment showed good or excellent results in 91.4% of the patients. The clinical outcome was not associated with the initial MASI score (P = 0.814; chi-square), skin colour (P = 0.449; probability ratio) or skin pigmentation (P = 0.814; chi-square). There was also a significant reduction on MelasQoL-BP scores (Wilcoxon test; P < 0.001) after treatment, with the mean +/- SD results shifting from 44.4 +/- 14.9 at baseline to 24.3 +/- 15.5 after treatment. The analysis of the MelasQoL-BP before and after treatment showed an important effect of the impact of treatment on a number of QoL measures. Of note, skin appearance (69.8 vs. 10.1% of patients were bothered all the time or most of the time, respectively), frustration (59.7% vs. 12.2%, respectively), embarrassment (56% vs. 9.3%, respectively) and influence of the disease on interpersonal relationships (35.3% vs. 5.8%, respectively) were greatly improved.

CONCLUSIONS

This study demonstrates that MelasQoL-BP is a valid instrument and can be used to evaluate the quality of life and response to melasma treatment in Brazilian patients. The triple combination treatment produced significant results, regarding both clinical severity and quality of life.

Preventive effects of phosphorylated ascorbate on ultraviolet-B induced apoptotic cell death and DNA strand cleavage through enrichment of intracellular vitamin C in skin epidermal keratinocytes

Mortality of mouse keratinocytes Pam212 that were irradiated with ultraviolet-B (UVB) was shown to be repressed by pre-irradiated administration with L-ascorbic acid (Asc) or more markedly with Asc-2-O-phosphate (Asc2P), but not with dehydroascorbic acid (DehAsc) or Asc-2-O-alpha-glucoside (Asc2G), although not repressed by post-irradiated administration. The cytoprotection by Asc2P was restricted against UVB below 5-20 mJ/cm2, and exhibited markedly by administration for a period over 2 h, which may be caused by intracellular Asc that was accumulated via dephosphorylation of Asc2P and was increased, 6-24 h after, to levels above twice as abundant as those of Asc-administration. Pre-irradiated Asc2P-administration slightly repressed a DNA ladder-like electrophoretic pattern for UVB-irradiated keratinocytes, containing the histone-bound DNA fragments as shown by ELISA assay, and appreciably repressed the DNA-3'OH cleavage terminals as shown by terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) stain. Thus, prevention of UVB-induced cell death by Asc2P was shown to occur concurrently with inhibition of DNA cleavages and enrichment of intracellular Asc.

8-Isoprostane is a dose-related biomarker for photo-oxidative ultraviolet (UV) B damage in vivo : a pilot study with personal UV dosimetry

BACKGROUND

Ultraviolet (UV) B irradiation causes visible erythema, which has been linked with DNA damage. However, besides such direct photochemical conformation changes, UVB also induces many indirect photochemical effects in the skin. Lipid peroxidation (LPO) is in this context one of the major pathways by which photo-oxidative stress disturbs cell signalling and promotes photocarcinogenesis and photoageing. So far we lack techniques for visualizing photo-oxidative stress in the skin. Furthermore, LPO has never been linked with individually acquired UVB doses measured by personal dosimetry.

OBJECTIVES

Measuring the skin reaction and photo-oxidative damage by LPO in vivo after UVB exposure in a pilot study surveyed by personal dosimetry in order to allow for a correlation analysis of acquired dose, skin reaction and amount of LPO.

METHODS

UVB exposure was measured with the opto-electronic X2000-1 (Gigahertz Optik, Puchheim, Germany) and the biological DLR Biofilm (German Aerospace Center DLR, Cologne, Germany) portable dosimeter. The skin reaction following UVB exposure was quantified with a Minolta chromameter (Minolta, Tokyo, Japan) and LPO in vivo was measured by 8-isoprostane generation by means of densitometric analysis of immunohistochemical samples obtained 30 min post-UVB irradiation.

RESULTS

Regression analysis revealed significant linear relations between UVB exposures recorded by the dosimeters and colorimetry parameters of the skin reaction. Furthermore, an even better linear relation with higher significance was found between the generation of 8-isoprostane in the skin and the dosimeter readouts.

CONCLUSIONS

LPO measured by the generation of 8-isoprostane provides a suitable intrinsic biomarker for photo-oxidative UVB damage in vivo. This study provides a new approach to visualizing photo-oxidative stress in the skin in vivo. Furthermore, future dosimeter readouts can now be set into relation to the expected increase of LPO that can be calculated within the limits of our study.

Reference Limits for Erythema-effective UV Doses

Diagnostic phototesting, including the determination of the minimal erythema dose (MED), is a useful procedure to detect abnormal sensitivity to UV radiation. We aimed to estimate the reference limits (RLs) of the MED in a reasonably large reference sample of white individuals. Skin phototypes and MED values for broadband UVB and for UVA were determined in 461 white subjects. When appropriate, the 95% reference intervals, including the 0.025 fractile and 0.975 fractile, were computed for the MED-UVB reference values (by means of parametric methods) and the MED-UVA reference values (by means of nonparametric methods). MED data were also converted to standard erythema doses (SEDs). As described elsewhere we observed a considerable overlap of MED values for all skin phototypes and confirmed that age and sex do not substantially influence the MED. The lower RLs observed for MED-UVB were 33 mJ cm(-2) (0.5 SEDs) and for MED-UVA 12.6 mJ cm(-2) (1.2 SEDs). The MED and SED findings from this investigation may serve as reference data for white individuals and give support to the clinician in differentiating between normal and pathologically abnormal photosensitivity. Although the MED data given here are limited to the phototest device used in the present study, the SED results establish comparability between our data and phototest results obtained from laboratories using different UV sources.

Determination of the minimal phototoxic dose and colorimetry in psoralen plus ultraviolet A radiation therapy

BACKGROUND

The use of an adequate initial dose of ultraviolet A (UVA) radiation for photochemotherapy is important to prevent burns secondary to overdosage, meanwhile avoiding a reduced clinical improvement and long-term risks secondary to underdosage. The ideal initial dose of UVA can be achieved based on the phototype and the minimal phototoxic dose (MPD). The objective measurement of constitutive skin color (colorimetry) is another method commonly used to quantify the erythematous skin reaction to ultraviolet radiation exposure. The aim of this study was to determine variations in MPD and constitutional skin color (coordinate L(*)) within different phototypes in order to establish the best initial dose of UVA radiation for photochemotherapy patients.

METHODS

Thirty-six patients with dermatological conditions and 13 healthy volunteers were divided into five groups according to phototype. Constitutional skin color of the infra-axillary area was assessed by colorimetry. The infra-axillary area was subsequently divided into twelve 1.5 cm(2) regions to determine the MPD; readings were performed 72 h after oral administration of 8-methoxypsoralen (MOP) followed by exposure of the demarcated regions to increasing doses of UVA.

RESULTS

The majority of the participants were women (73.5%) and their mean age was 38.8 years. The MPD ranged from 4 to 12 J/cm(2) in phototypes II and III; from 10 to 18 J/cm(2) in type IV; from 12 to 24 J/cm(2) in type V and from 18 to 32 J/cm(2) in type VI. The analysis of colorimetric values (L(*) coordinate) and MPD values allowed the definition of three distinctive groups of individuals composed by phototypes II and III (group 1), types IV and V (group 2), and phototype VI (group 3).

CONCLUSIONS

MPD and L(*) coordinate showed variation within the same phototype and superposition between adjacent phototypes. The values of the L(*) coordinate and the MPD lead to the definition of three distinct sensitivity groups: phototypes II and III, IV and V and type VI. Also, the MPD values bear a strong correlation to coordinate L(*) values. Mean MPD values described for each of the three major sensitivity groups were higher than the values commonly used in clinical settings for the different phototypes. Therefore, phototype alone is not a good parameter to define the initial UVA dose. MPD and colorimetry could be used in pre-treatment evaluation of patients who are to be submitted to photochemotherapy, in a non-invasive and more accurate way when compared with the classical phenotype clinical criteria.

Late cornified envelope family in differentiating epithelia--response to calcium and ultraviolet irradiation

The late cornified envelope (LCE) gene cluster within the epidermal differentiation complex on human chromosome one (mouse chromosome three) contains multiple conserved genes encoding stratum-corneum proteins. Within the LCE cluster, genes form "groups" based on chromosomal position and protein homology. We link a recently accepted nomenclature for the LCE cluster (formerly XP5, small proline-rich-like, late-envelope protein genes) to gene structure, groupings, and chromosomal organization, and carry out a pan-cluster quantitative expression analysis in a variety of tissues and environmental conditions. This analysis shows that (i) the cluster organizes into two "skin" expressing groups and a third group with low-level, tissue-specific expression patterns in all barrier-forming epithelia tested, including internal epithelia; (ii) LCE genes respond "group-wise" to environmental stimuli such as calcium levels and ultraviolet (UV) light, highlighting the functional significance of groups; (iii) in response to UV stimulation there is massive upregulation of a single, normally quiescent, non-skin LCE gene; and (iv) heterogeneity occurs between individuals with one individual lacking expression of an LCE skin gene without overt skin disease, suggesting LCE genes affect subtle attributes of skin function. This quantitative and pan-cluster expression analysis suggests that LCE groups have distinct functions and that within groups regulatory diversification permits specific responsiveness to environmental challenge.