The protective effect of a novel sunscreen against blue light.

BACKGROUND AND OBJECTIVE: Premature skin ageing, and skin hyperpigmentation are influenced by exogenous factors, such as ultraviolet radiation and blue light. In this study, we assess the protective effect of a sunscreen (TDF® Blu Voile Sunscreen) in protecting the skin against the harmful effects of blue light irradiation in vivo and through the in situ quantitative and qualitative evaluation of protein carbonylation in human skin explants. METHODOLOGY: The protective effect of the test product against blue light was first evaluated ex vivo on human skin explants. The treated and non-treated explants were exposed to 14 J/cm2 of blue light 460 nm following which the protein carbonylation was evaluated by in situ epifluorescence imaging and separation by high-resolution gel electrophoresis. To determine whether the test product could also protect against the immediate and persistent pigmenting effect of blue light, two randomized in vivo studies were conducted, which included respectively 17 subjects with a skin phototype of IV and V (Fitzpatrick classification) and 22 subjects with a skin phototype of IV, V, and VI (Fitzpatrick classification). The duration of the study for each subject was 2 days (D1 and D2) for immediate observations and 5 days (D1-D5) for persistent observations. Specific zones on the subjects' back were either left non-treated or treated with the test product and were then exposed to a unique dose of blue light 415 nm. The onset of pigmentation between the treated and exposed zones was then assessed relative to the non-exposed treated zone through colorimetric measurements of the Individual Typology Angle (ITAo ). RESULTS: Human skin explants treated with test product showed significantly lower levels of accumulated carbonylated proteins, with a protection of 82%, following exposure to blue light 460 nm. Findings of the in vivo studies also indicated that the test product presented significantly better protective efficacy against immediate and persistent pigmentation induced by blue light 415 nm. CONCLUSION: Hence, it can be concluded that the test product can protect against the oxidative stress as well as the immediate and persistent pigmentation induced by blue light.

CONTEXTE ET OBJECTIF: Le vieillissement prématuré de la peau et l'hyperpigmentation cutanée sont influencés par des facteurs exogènes, tels que les rayons ultraviolets et la lumière bleue. Dans cette étude, nous évaluons l'effet protecteur d'un écran solaire (TDF® Blu Voile Sunscreen) en matière de protection de la peau contre les effets nocifs de l'irradiation à la lumière bleue in vivo et par l'évaluation quantitative et qualitative in situ de la carbonylation des protéines dans des explants cutanés humains. MÉTHODOLOGIE: L'effet protecteur du produit testé contre la lumière bleue a d'abord été évalué ex vivo sur des explants cutanés humains. Les explants traités et non traités ont été exposés à 14 J/cm2 de lumière bleue à 460 nm, après quoi la carbonylation des protéines a été évaluée par imagerie par épifluorescence in situ et séparation par électrophorèse sur gel à haute résolution. Afin de déterminer si le produit testé pouvait également protéger contre la pigmentation immédiate et persistante dues à lumière bleue, deux études in vivo randomisées incluant respectivement 17 sujets ayant un phototype cutané IV et V (classification de Fitzpatrick) et 22 sujets ayant un phototype cutané IV, V et VI (classification de Fitzpatrick) ont été menées. La durée de l'étude pour chaque sujet était de 2 jours (J1 et J2) pour les observations immédiates et de 5 jours (J1 à J5) pour les observations persistantes. Des zones spécifiques du dos des sujets ont été laissées non traitées ou bien traitées avec le produit testé, et ont ensuite été exposées à une dose unique de lumière bleue à 415 nm. L'apparition de la pigmentation entre les zones traitées et exposées a ensuite été évaluée par rapport à la zone traitée non exposée par des mesures colorimétriques de l'angle typologique individuel (Individual Typology Angle, ITAo). RÉSULTATS: Les explants cutanés humains traités avec le produit testé ont montré des taux significativement plus faibles de protéines carbonylées accumulées, avec une protection de 82 %, après une exposition à la lumière bleue à 460 nm. Les résultats des études in vivo ont également indiqué que le produit testé présentait une efficacité protectrice significativement meilleure contre la pigmentation immédiate et persistante induite par la lumière bleue à 415 nm. CONCLUSION: Par conséquent, on peut conclure que le produit testé peut protéger contre le stress oxydatif ainsi que contre la pigmentation immédiate et persistante induite par la lumière bleue.

Impact of RNA Virus Evolution on Quasispecies Formation and Virulence.

RNA viruses are known to replicate by low fidelity polymerases and have high mutation rates whereby the resulting virus population tends to exist as a distribution of mutants. In this review, we aim to explore how genetic events such as spontaneous mutations could alter the genomic organization of RNA viruses in such a way that they impact virus replications and plaque morphology. The phenomenon of quasispecies within a viral population is also discussed to reflect virulence and its implications for RNA viruses. An understanding of how such events occur will provide further evidence about whether there are molecular determinants for plaque morphology of RNA viruses or whether different plaque phenotypes arise due to the presence of quasispecies within a population. Ultimately this review gives an insight into whether the intrinsically high error rates due to the low fidelity of RNA polymerases is responsible for the variation in plaque morphology and diversity in virulence. This can be a useful tool in characterizing mechanisms that facilitate virus adaptation and evolution.

Benefits of the Dermocosmetic Mineral 89 Probiotic Fractions Adjunct to Topical Retinoids for Anti-Aging Benefits.

Purpose: Tretinoin is a topical gold standard for photoaging treatment. However, patient adherence can be impaired by local tolerability in the first 1-2 weeks of treatment. Mineral 89 Probiotic Fractions® (M89PF) containing Vichy volcanic mineralizing water®, probiotic fractions, hyaluronic acid, niacinamide and tocopherol was developed to fulfill the need for adjunctive products that can reinforce skin barrier and manage retinoid induced irritation. Patients and Methods: The study included 38 women, aged 44-60 years, phototype II-VI, applying 0.025% tretinoin gel once nightly for 84 days. For 28 days, one hemi face was treated with M89PF and sunscreen SPF 50+ while other hemi face received sunscreen only. Then, M89PF application was changed to full face. Evaluations were performed at days 0, 7, 28 and 84. Erythema, dryness, fine lines, skin tone, radiance and pore appearance were assessed by a dermatologist. Tolerability was evaluated through self-assessment questionnaire. Skin hydration levels, inflammatory and oxidative stress biomarkers were analyzed by immunological assay: Interleukin(IL)-8, IL1-alpha, IL1-Receptor Antagonist (IL-1Ra), Prostaglandin E2 (PGE2), Catalase and Superoxide Dismutase (SOD). Results: Hemiface analysis showed that erythema, fine lines, skin tone, radiance, pore appearance, hydration, tightness, dryness, burning, itching and stinging sensations were improved (p<0.05) on the M89PF side. At full face analysis on D84, erythema, fine lines, skin tone, radiance and pore appearance were improved compared to D0 (p<0.001). Tightness, dryness, burning, itching and stinging were reduced when compared to D7 (p<0.05). Dermatology Life Quality Index (DLQI) and Skindex 16 showed improvement in quality of life (p<0.05). IL-1RA increased at D28 (p=0.003) and PGE2 decreased at D28 and D84 compared to D0 (p<0.01). Conclusion: M89PF reduced retinoid induced irritation with a good tolerability profile and, used as an adjunct to topical tretinoin, significantly improved skin hydration, erythema, fine lines, skin tone, radiance and pore appearance.

Characterization of Plaque Variants and the Involvement of Quasi-Species in a Population of EV-A71.

Viral plaque morphologies in human cell lines are markers for growth capability and they have been used to assess the viral fitness and selection of attenuated mutants for live-attenuated vaccine development. In this study, we investigate whether the naturally occurring plaque size variation reflects the virulence of the variants of EV-A71. Variants of two different plaque sizes (big and small) from EV-A71 sub-genotype B4 strain 41 were characterized. The plaque variants displayed different in vitro growth kinetics compared to the parental wild type. The plaque variants showed specific mutations being present in each variant strain. The big plaque variants showed four mutations I97L, N104S, S246P and N282D in the VP1 while the small plaque variants showed I97T, N237T and T292A in the VP1. No other mutations were detected in the whole genome of the two variants. The variants showed stable homogenous small plaques and big plaques, respectively, when re-infected in rhabdomyosarcoma (RD) and Vero cells. The parental strain showed faster growth kinetics and had higher viral RNA copy number than both the big and small plaque variants. Homology modelling shows that both plaque variants have differences in the structure of the VP1 protein due to the presence of unique spontaneous mutations found in each plaque variant This study suggests that the EV-A71 sub-genotype B4 strain 41 has at least two variants with different plaque morphologies. These differences were likely due to the presence of spontaneous mutations that are unique to each of the plaque variants. The ability to maintain the respective plaque morphology upon passaging indicates the presence of quasi-species in the parental population.

Changes in the EV-A71 Genome through Recombination and Spontaneous Mutations: Impact on Virulence.

Enterovirus 71 (EV-A71) is a major etiological agent of hand, foot and mouth disease (HFMD) that mainly affects young children less than five years old. The onset of severe HFMD is due to neurological complications bringing about acute flaccid paralysis and pulmonary oedema. In this review, we address how genetic events such as recombination and spontaneous mutations could change the genomic organization of EV-A71, leading to an impact on viral virulence. An understanding of the recombination mechanism of the poliovirus and non-polio enteroviruses will provide further evidence of the emergence of novel strains responsible for fatal HFMD outbreaks. We aim to see if the virulence of EV-A71 is contributed solely by the presence of fatal strains or is due to the co-operation of quasispecies within a viral population. The phenomenon of quasispecies within the poliovirus is discussed to reflect viral fitness, virulence and its implications for EV-A71. Ultimately, this review gives an insight into the evolution patterns of EV-A71 by looking into its recombination history and how spontaneous mutations would affect its virulence.