A Bayesian network meta-analysis of 14 molecules inhibiting UV daylight-induced pigmentation.

INTRODUCTION: Hyperpigmentation disorders are very frequent, affect the quality of life and may become a psychological burden for afflicted patients. Many anti-pigmenting or depigmenting agents are available with various efficacy and almost no comparative data. 2-mercaptonicotinoyl glycine (2-MNG) was recently proposed as a viable candidate showing safe and effective results on hyperpigmentation control in vitro and in vivo. OBJECTIVES: A Bayesian network meta-analysis (BNMA) was conducted to map and rank the anti-pigmenting and depigmenting efficacy of 2-MNG 0.5% on UV daylight (UVDL)-induced pigmentation together with 13 other reference molecules. A comparison in the kinetics of 2-MNG 0.5% was also performed. METHODOLOGY: Fourteen studies were conducted, for each, on 15-30 women of skin phototype III in Shanghai, China and Paris, France. The products were applied on mini zone, in randomized and blinded protocol, on the back, 5 days a week during 6 weeks, at a dose of 4 mg/cm2 . During the second week, volunteers were exposed under to varying minimum erythemal dose of UVDL during 4 consecutive days-adapted to obtain a similar induction of skin pigmentation regardless of the population. Assessments were performed instrumentally using Chromameter®. Ascorbic acid 7% was used as a positive control for all experiments. A Bayesian network meta-analysis was then established to map and follow the kinetics of 2-MNG 0.5% performance with 13 reference molecules (glutathione 2%, kojic acid 1%, hydroquinone 4%, ascorbyl glucoside 2%, niacinamide 4%, etc.). RESULTS: 2-MNG 0.5% dominated the ranking at all time points with a significant high probability of strong efficacy against UVDL-induced pigmentation. Ascorbic acid 7% ranks second after 4 days of irradiations (D12 ) whereas hydroquinone 4% ranks second 1 month after irradiations (D40 ). In the kinetics, 2-MNG at 0.5% was effective as from the end of irradiations (D12 ) to the study endpoint (D40 ). This suggested an immediate and persistent efficacy across all timepoints evaluated. CONCLUSION: The BNMA revealed a rapid and lasting efficacy of 2-MNG 0.5% on the anti-pigmenting and depigmenting phases of the clinical protocol. 2-MNG 0.5% ranked first, with immediate and lasting effect compared to 13 other references. This study is the first allowing comparison between reference anti-pigmenting and depigmenting agents and will help clinicians for proposing the most effective approach for their patients.

Predicting the evolution of clinical skin aging in a multi-ethnic population: Developing causal Bayesian networks using dermatological expertise.

INTRODUCTION: Software to predict the impact of aging on physical appearance is increasingly popular. But it does not consider the complex interplay of factors that contribute to skin aging. OBJECTIVES: To predict the +15-year progression of clinical signs of skin aging by developing Causal Bayesian Belief Networks (CBBNs) using expert knowledge from dermatologists. MATERIAL AND METHODS: Structures and conditional probability distributions were elicited worldwide from dermatologists with experience of at least 15 years in aesthetics. CBBN models were built for all phototypes and for ages ranging from 18 to 65 years, focusing on wrinkles, pigmentary heterogeneity and facial ptosis. Models were also evaluated by a group of independent dermatologists ensuring the quality of prediction of the cumulative effects of extrinsic and intrinsic skin aging factors, especially the distribution of scores for clinical signs 15 years after the initial assessment. RESULTS: For easiness, only models on African skins are presented in this paper. The forehead wrinkle evolution model has been detailed. Specific atlas and extrinsic factors of facial aging were used for this skin type. But the prediction method has been validated for all phototypes, and for all clinical signs of facial aging. CONCLUSION: This method proposes a skin aging model that predicts the aging process for each clinical sign, considering endogenous and exogenous factors. It simulates aging curves according to lifestyle. It can be used as a preventive tool and could be coupled with a generative AI algorithm to visualize aging and, potentially, other skin conditions, using appropriate images.

Efficacy of a multitargeted, salicylic acid-based dermocosmetic cream compared to benzoyl peroxide 5% in Acne vulgaris: Results from a randomized study.

INTRODUCTION: Acne vulgaris (acne) is characterized by both inflammatory and non-inflammatory lesions. Benzoyl peroxide (BPO) 5% is approved to treat acne but may cause skin irritation and/or contact allergy. OBJECTIVES: To compare the benefit in acne of a multitargeted dermocosmetic cream containing salicylic acid, lipohydroxy acid, niacinamide, 2-oleamido-1,3-octadecanediol, piroctone olamine, zinc, Aqua posae filiformis, and thermal spring water (DC-Eff) to BPO 5% gel. MATERIALS AND METHODS: 150 Caucasian subjects (50% female) aged between 18 and 40 years, with mild to moderate acne according to the GEA (Global Evaluation of Acne) grading system were randomized into two parallel groups (DC-Eff or BPO to be applied twice daily for 56 days). IGA (investigator global assessment), GEA, lesion count, clinical signs and symptoms, and subject assessment were evaluated at baseline, and after 28 and 56 days (D28 and D56) of treatment. RESULTS: The responder analyses of the IGA and GEA scores showed that 62.2% and 47.3%, respectively, in the DC-Eff, compared with 50.0% and 36.5%, respectively, in the BPO, had improved by at least one point at D56. Inflammatory, non-inflammatory, and total lesion counts significantly (p < 0.0001) decreased with both products from baseline, with no between-group difference. Subjects considered that their skin was smoother and that DC-Eff was easy to apply. DC-Eff was better tolerated than BPO. CONCLUSIONS: DC-Eff applied twice daily is as beneficial as BPO in improving mild-to-moderate acne. DC-Eff was better tolerated than BPO and highly appreciated.

Maintenance effect of a once-weekly regimen of a Selenium Disulfide-based shampoo in moderate-to-severe scalp seborrheic dermatitis after initial treatment with topical corticosteroid/salicylic acid.

INTRODUCTION: Seborrheic dermatitis (SD) is a chronic, relapsing, inflammatory disorder of the head and trunk. OBJECTIVES: To explore the potential of a 1% Selenium disulphide (SeS2)-based shampoo to prevent relapses of scalp SD (SSD) following corticosteroid/salicylic acid (TCS/SA) treatment. MATERIALS & METHODS: After a 2-week treatment with TCS/SA, adult patients with moderate-to-severe SSD received either the SeS2-based shampoo or its vehicle for eight weeks in a randomized, double-blinded fashion. Visits took place at baseline, weeks 2, 6 and 10. SSD severity was assessed based on erythema, flakes and pruritus; patients assessed the severity of pruritus. Global investigator and patient satisfaction were assessed at week 10. RESULTS: Forty-eight adults were included. After four and eight weeks of post TCS/SA maintenance regimen, 8.1% and 16.7% in the SeS2, and 41.7% and 54.2% in the vehicle group relapsed, respectively. First median time-to-relapse in the vehicle group was 56 days; this was not reached for SeS2. After two weeks of TCS/SA, the prevalence of patients with no pruritus was 29.2% in the SeS2 group, and 41.7% in the vehicle group; it increased to 76.2% with SeS2 and to 57.1% with the vehicle at the end of the study. The clinical benefit of treatment with TCS/SCA was maintained in the SeS2 group only. Investigators and patients were highly satisfied with the efficacy of SeS2. Tolerance to SeS2 was excellent, with no reported adverse events. CONCLUSION: The SeS2-based shampoo significantly reduces the time-to-relapse of moderate-to-severe SSD flares. Its tolerance was excellent, with no reported adverse events.

A precise analysis of the relative contribution of UVA1 and visible light colour domains in solar light-induced skin pigmentation.

BACKGROUND: Solar light induces or aggravates hyperpigmentation issues. The contribution of UVA1, as well as visible light (VL), especially high-energy blue-violet visible (HEV) light, is now clearly established. OBJECTIVES: This work aimed at determining the relative contribution of UVA1, HEV and VL wavelength bands and their sub-domains in pigmentation induction. METHODS: Two clinical studies using solar simulators equipped with specific bandpass physical filters were carried out. Volunteers (FSPT III-IV) were exposed on the back to UVA1 + HEV (350-450 nm), UVA1 (350-400 nm), HEV (400-450 nm) or part of UVA1 + HEV (370-450 nm) in Study 1 (n = 27) and to VL (400-700 nm), HEV (400-450 nm), Blue (400-500 nm), Green (500-600 nm) and Green+Red (500-700 nm) domains in Study 2 (n = 25). Pigmentation level was assessed by visual scoring and colorimetry at different time points postexposure, up to Day 43. RESULTS: Induced pigmentation was detected in all exposed conditions, peaking at 2 h and thereafter progressively decreasing but remaining persistent up to Day 43. In Study 1, UVA1 showed an additive effect with HEV, with a significant contribution coming from the Longest UVA1 rays (370-400 nm). Study 2 demonstrated that 24 h postexposure, the Blue domain accounted for 71% of VL-induced pigmentation, the HEV one for 47%, the Green one for 37% and the Green+Red one for 36%, confirming no significant effect for Red light. CONCLUSIONS: Altogether, these results underline the need for UVA1 photoprotection up to 400 nm and highlight the importance of protecting the skin from solar VL wavelengths and especially from HEV, Blue and Green light, to limit induced pigmentation.