Effect of vitamin D status and vitamin D supplementation on immune function and prevention of acute respiratory tract infections in dark-skinned individuals: a systematic review and meta-analysis.

OBJECTIVE: This systematic review and meta-analysis examined the evidence for a potential relationship between vitamin D status and vitamin D supplementation on immune function biomarkers and prevention of acute respiratory tract infections (ARTI) in dark-skinned individuals. DESIGN: Six databases were searched (inception to December 2021) for randomised controlled trials (RCT) and observational studies. A narrative synthesis and random-effects meta-analysis were used to synthesise the findings. SETTING: Not applicable. PARTICIPANTS: Ethnic groups other than white, with or without a white comparator. RESULTS: After duplicates were removed, 2077 articles were identified for screening. A total of eighteen studies (n 36 707), including seven RCT and 11 observational studies, met the inclusion criteria, and three RCT (n 5778) provided sufficient data of high enough quality to be included in a meta-analysis. An inverse association between vitamin D status and at least one inflammatory biomarker in black adults was found in three studies, and vitamin D status was inversely associated with ARTI incidence in black and Indigenous groups in two studies. There was no significant effect of vitamin D supplementation on differences in ARTI incidence in ethnic minority groups (OR, 1·40; 95 % CI: 0·70, 2·79; P = 0·34), nor African American (OR, 1·77; 95 % CI: 0·51, 6·19; P = 0·37) or Asian/Pacific (OR, 1·08; 95 % CI: 0·77, 2·68; P = 0·66) subgroups. CONCLUSIONS: There is a lack of conclusive evidence supporting an association between vitamin D status and immune function or ARTI incidence in dark-skinned individuals. Further RCT in diverse ethnic populations are urgently needed.

Modulating OCA2 Expression as a Promising Approach to Enhance Skin Brightness and Reduce Dark Spots.

The oculocutaneous albinism II (OCA2) gene encodes a melanosomal transmembrane protein involved in melanogenesis. Recent genome-wide association studies have identified several single nucleotide polymorphisms within OCA2 genes that are involved in skin pigmentation. Nevertheless, there have been no attempts to modulate this gene to improve skin discoloration. Accordingly, our aim was to identify compounds that can reduce OCA2 expression and to develop a formula that can improve skin brightness and reduce hyperpigmented spots. In this study, we investigated the effects of OCA2 expression reduction on melanin levels, melanosome pH, and autophagy induction through siRNA knockdown. Additionally, we identified several bioactives that effectively reduce OCA2 expression. Ultimately, in a clinical trial, we demonstrated that topical application of those compounds significantly improved skin tone and dark spots compared to vitamin C, a typical brightening agent. These findings demonstrate that OCA2 is a promising target for the development of efficacious cosmetics and therapeutics designed to treat hyperpigmentation.

Implementing differentially pigmented skin models for predicting drug response variability across human ancestries.

Persistent racial disparities in health outcomes have catalyzed legislative reforms and heightened scientific focus recently. However, despite the well-documented properties of skin pigments in binding drug compounds, their impact on therapeutic efficacy and adverse drug responses remains insufficiently explored. This perspective examines the intricate relationships between variation in melanin-based skin pigmentation and pharmacokinetics and -dynamics, highlighting the need for considering diversity in skin pigmentation as a variable to advance the equitability of pharmacological interventions. The article provides guidelines on the selection of New Approach Methods (NAMs) to foster inclusive study designs in preclinical drug development pipelines, leading to an improved level of translatability to the clinic.

Treatment of Acne Vulgaris-Associated Post-Inflammatory Dyschromia With Combination of Non-Ablative Laser Therapy and Topical Antioxidants.

Acne can cause disfiguring sequelae, such as scarring, post-inflammatory erythema (PIE), and post-inflammatory hyperpigmentation (PIH). These post-inflammatory dyschromias pose a significant psychological burden on patients. This burden disproportionately affects skin of color (SOC) patients and can be the most distressing aspect of acne in SOC patients with skin types IV to VI. Multiple non-ablative lasers are used in the treatment of acne-related PIE and PIH. Combination therapies have shown promise in conditions such as rosacea, acne, and post-inflammatory dyschromia. Addressing both the inflammatory and scarring components of acne is key. Given the role of oxidation in the inflammatory cascade, including antioxidants could be an efficacious adjuvant with non-ablative lasers. This is a single-site, randomized, controlled clinical study of 25 subjects with skin types I to VI with facial PIE and/or PIH from acne. The primary objective was to investigate the clinical efficacy of non-ablative laser therapy followed by the topical application of Silymarin/Salicylic Acid/L-Ascorbic Acid/Ferulic Acid (SSAF) or control in the improvement in oily skin patients with facial PIE and PIH due to acne lesions. There was a statistically significant decrease in PIH and intralesional melanin in patients treated with a combination SSAF and non-ablative laser therapy. Improvement of both PIE and PIH was augmented in combination with SSAF and laser-treated patients compared with the laser-only group, with a concomitant increase in collagen density. This was even more strikingly marked in the SOC subjects, potentially providing an energy-based device (EBD)-based therapy in this population. Limitations of this study include small sample size and length of post-treatment follow-up. J Drugs Dermatol. 2024;23(9):769-773. doi:10.36849/JDD.8309.

Efficacy and safety of ritlecitinib in vitiligo patients across Fitzpatrick skin types with biomarker analyses.

Efficacy and safety of ritlecitinib (an oral JAK3/TEC family kinase inhibitor) were evaluated in patients with nonsegmental vitiligo (NSV) across Fitzpatrick skin types (FSTs). Patients with FST I-III ('light skin'; n = 247) and FST IV-VI ('dark skin'; n = 117) received once-daily ritlecitinib 50 mg (with/without 4-week loading dose), low-dose ritlecitinib or placebo for 24 weeks. At baseline, patients with light skin displayed higher CLM-1 and NCR1 serum levels than patients with dark skin (p < 0.05). At 24 weeks, ritlecitinib 50 mg improved the extent of depigmentation measured by percent change from baseline in facial-vitiligo area scoring index (placebo-adjusted mean difference [90% CI]) in patients with light (-15.2 [-24.7, -5.8]; p = 0.004) and dark (-37.4 [-50.3, -24.4]; p < 0.0001) skin, with continuous re-pigmentation through week 48. Treatment-emergent adverse events were similar across FSTs. At weeks 4 and 24, ritlecitinib 50 mg reduced CXCL11 serum levels (p < 0.001) in patients with light skin, whereas patients with dark skin had increased levels at week 4 (p = 0.05) and no significant change at week 24. Ritlecitinib 50 mg decreased IL-9 and IL-22 expression levels in dark skin compared with light skin (qPCR; p < 0.05). These differences in immune dysregulations may explain why NSV patients with dark skin respond to therapy earlier than patients with light skin.

Enhanced stability and reduced irritation of 4-n-butylresorcinol via nanoemulsion formulation: Implications for skin pigmentation treatment.

4-n-butylresorcinol (4-nBR) is a valuable ingredient to lighten skin and reduce pigmentation, contributing to an even skin tone and a more youthful appearance. However, its poor solubility, low stability, and strong irritation to the skin limit its application. In this study, 4-nBR was prepared into 4-n-butylresorcinol nanoemulsion (4-nBR-NE) for the first time, enhancing the solubility and stability of 4-nBR while greatly reducing its skin irritation. The relationship between the viscosity of nanoemulsion and the formulation process, as well as the impact of surfactant ratio on the formability of 4-nBR-NE were further studied. This led to the successful development of a nanoemulsion with adjustable viscosity (AV-NE) and with a low surfactant content. The particle size of 4-nBR-NE was 13.34 ± 0.16 nm with a PDI of 0.0853 ± 0.0191, indicating a uniform particle size distribution. The encapsulation rate of 4-nBR-NE was determined to be 80.05 ± 0.75 % via UV-Vis spectrophotometry. In addition, 4-nBR-NE demonstrated excellent stability over several months, with negligible changes in particle size. Cellular and transdermal evaluations confirmed that the preparation of 4-nBR-NE effectively reduced the original irritation cause by 4-nBR on cells and skin. Then, 4-nBR-NE was incorporated into an essence. This advancement enhances the applicability of 4-nBR in treating pigmentation disorders such as melasma and freckles, thereby increasing its applicability in pharmaceutical and cosmetic industries.

Oral administration of cysteine peptides attenuates UV-B-induced skin erythema and pigmentation in humans.

The oral administration of antioxidants may suppress UV-B-induced skin damage. HITHION YH-15, the extract of Torula yeast (Cyberlindnera jadinii), is rich in cysteine-containing peptides such as reduced and oxidized glutathione (GSH and GSSG), γ-glutamylcysteine (γ-Glu-Cys), and cysteinylglycine (Cys-Gly). These four constituents are termed cysteine peptides. In this study, we investigated the protective effects of cysteine peptides against UV-B in a randomized, placebo-controlled, double-blind, parallel-group study. A total of 90 healthy males and females aged 30-59 years were enrolled and randomized into two groups of 45 individuals each (cysteine peptides (48 mg/day) and placebo). Changes in UV-B-induced erythema and pigmentation were compared between groups after 5 weeks of test food intake. The minimal erythema dose (MED) significantly increased (*p = 0.019) in the cysteine peptides group compared to that in the placebo group, indicating suppression of UV-B-induced erythema. ΔL* value significantly increased (***p < 0.0001) in the cysteine peptides group compared to that in the placebo, indicating pigmentation suppression. We demonstrated that oral administration of cysteine peptides suppresses UV-B-induced erythema and pigmentation through multiple mechanisms. Thus, cysteine peptides may find use as nutricosmetics for maintaining skin health and well-being.UMIN Clinical Trials Registry ID: UMIN 000050157.

Efficacy and Safety of Secukinumab in the Treatment of Psoriasis in Patients with Skin Phototypes IV to VI.

BACKGROUND: There is a paucity of data on the treatment of psoriasis in patients with skin of color – a diverse population among whom variations in clinical features and higher quality of life impact have been reported. This single-center, open-label clinical study evaluated the safety and efficacy of secukinumab in the treatment of moderate-to-severe plaque psoriasis in adults with Fitzpatrick skin types IV-VI. METHODS: A total of 20 male and female subjects (ages ≥ 18, BSA ≥10%, PASI Score ≥ 12, IGA ≥ 3) completed this study. The total study duration was 28 weeks. During the treatment period, subjects received secukinumab 300 mg subcutaneously at weeks 0, 1, 2, 3, and 4, then monthly through week 20. RESULTS: 73% of patients achieved at least 90% improvement in PASI score (PASI90) at week 16 compared to baseline (P=0.0592). There was a statistically significant proportion of patients achieving PASI75, IGA of clear or almost clear, and a change from baseline in DLQI total score at weeks 12, 16, and 24. A statistically significant reduction in IGAxBSA-75 score was achieved between week 16 and baseline. LIMITATIONS: The sample size was small and underpowered to detect statistically significant changes in some endpoints. Furthermore, the study period was interrupted by the COVID-19 pandemic, which contributed to numerous missing data points. CONCLUSION: Secukinumab 300 mg administered monthly was safe, well-tolerated, and efficacious in treating skin of color patients with psoriasis and improving health-related quality of life. Larger studies involving skin of color populations with psoriasis are warranted. J Drugs Dermatol. 2024;23(8):600-606. doi:10.36849/JDD.8128.

Antioxidant and Skin-Whitening Efficacy of a Novel Decapeptide (DP, KGYSSYICDK) Derived from Fish By-Products.

The skin is vulnerable to damage from ultraviolet rays and oxidative stress, which can lead to aging and pigmentation issues. This study investigates the antioxidant and whitening efficacy of a decapeptide (DP, KGYSSYICDK) derived from marine fish by-products and evaluates its potential as a new skin-whitening agent. DP demonstrated high antioxidant activity, showing comparable or superior performance to Vitamin C (Vit. C) in ferric reducing antioxidant power (FRAP) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assays. In hydrogen peroxide (H2O2)-treated HaCaT cells, DP increased cell viability and reduced reactive oxygen species (ROS) generation. Furthermore, DP inhibited tyrosinase activity and decreased melanin production in α-melanocyte stimulating hormone (α-MSH)-induced B16F10 melanoma cells in a dose-dependent manner. Reverse transcription polymerase chain reaction (RT-PCR) analysis revealed that DP reduces the mRNA expression of MITF, tyrosinase, and MC1R, thus suppressing melanin production. DP exhibits strong binding interactions with multiple amino acid residues of tyrosinase, indicating potent inhibitory effects on the enzyme. These results suggest that DP possesses significant antioxidant and whitening properties, highlighting its potential as a skin-whitening agent. Future research should focus on optimizing DP's structure and exploring structure-activity relationships.

Neuromodulators in Skin of Color: An International Review.

BACKGROUND: As the racial/ethnic diversity of the US population grows, it is imperative for dermatologists to recognize the nuances in the aesthetic treatment of diverse populations. OBJECTIVE: This comprehensive review explores the safety and efficacy of botulinum toxin A (BTX-A) in skin of color (SOC) populations and highlights variations in aging patterns, skin properties, and aesthetic concerns in SOC populations. MATERIALS AND METHODS: A review of PubMed/MEDLINE databases from 2004 to 2024 was performed using combinations of the terms botulinum toxin, SOC, Fitzpatrick, race/ethnicity, and Asian, Latin American, Caribbean, Middle Eastern, African, and Pacific countries. RESULTS: Twenty-three articles examining the use of BTX-A in SOC populations were identified. Twelve studies were from East Asia, 5 from the United States and/or Canada, 3 from South Asia/Southeast Asia, 2 from South America, and 1 from the Middle East. Available data suggest that BTX-A is efficacious and well tolerated in SOC populations. CONCLUSION: Increased SOC representation in clinical trials may guide the development of tailored treatment approaches to optimize aesthetic outcomes for patients with SOC. A comprehensive knowledge of the variations in aging patterns, skin properties, and aesthetic concerns across SOC populations is essential for providing culturally sensitive cosmetic dermatologic care for diverse populations.

Photo Visualization of Skintone Compatibility of an SPF 35 Sunscreen.

BACKGROUND: Visual casts and discoloration are common barriers to sunscreen use in melanin-rich populations. However, photoprotective measures are essential for individuals with all skin types, including darker skin. METHODS: Single-center, 7-day, open-label study of healthy adult females with Fitzpatrick Skin Types (FST) IV to VI and sensitive skin treated with once-daily daily facial moisturizer sun protection factor 35 (DFM SPF35). Subjects completed a cosmetic acceptability questionnaire at days 1 and 7. Photography using VISIA CR was performed at day 7. Adverse events were monitored throughout the study. RESULTS: Thirty-two (32) subjects participated; 31.3% had FST IV, 53.1% V, and 15.6% VI skin. DFM SPF35 was viewed as cosmetically elegant. At day 1, 96.7% of subjects agreed product was easy to apply; 90.0% reported soft skin after product use; 86.7% said it had a lightweight, non-greasy feel and hydrated the skin. At day 7, 93.7% reported no visible white residue on their skin and said the product applied easily/absorbed well. The majority (90.6%) would continue using and would recommend the product; and 87.5% reported the product blended seamlessly into their skin, which agreed with clinical photography. Responses were consistent among subjects with normal, oily, or combination skin. No adverse events were reported. CONCLUSIONS: DFM SPF35 blended well into the skin and was perceived favorably among subjects with SOC after 1 and 7 days of use. Subjects felt it had good cosmetic acceptability without unacceptable white residues or a greasy feeling. Dermatologists need to be versed in products that can be used on a variety of skin types.J Drugs Dermatol. 2024;23(7):515-518.  doi:10.36849/JDD.8223.

Effects of a Sheer 100% Mineral Sunscreen Moisturizer on Facial Photodamage Across Fitzpatrick Skin Types.

BACKGROUND: All skin tones need to be protected from the damaging effects of solar radiation. Although mineral sunscreens offer protection, they can have a thick, greasy feel and leave a white cast, particularly on darker skin tones. Tints offset white cast and provide visible light protection; however, patients may prefer a sheer option. Therefore, a multifunctional, sheer, 100% mineral sunscreen moisturizer (MSM) with broad-spectrum SPF 50 was developed to have positive aesthetics and deliver anti-aging and skin health benefits to all skin tones.  Methods: An IRB-approved, 12-week, open-label clinical study was conducted to investigate the efficacy and tolerability of the MSM. Thirty-nine (39) females aged 35 to 60 years with moderate-severe overall facial photodamage and representing all Fitzpatrick skin types (FST) were recruited. Participants applied the MSM to the face and neck in the morning and reapplied per US Food and Drug Administration requirements. Efficacy and tolerability grading, photography, ultrasound imaging, corneometer measurements, and questionnaires were completed at baseline and weeks 4, 8, and 12.  Results: Statistically significant progressive improvements were demonstrated from baseline to week 12. At week 12, 23.4% and 26.5% mean improvements in overall photodamage were seen for FST I-III and FST IV-VI, respectively. Favorable tolerability was shown for both the face and neck. Photography corroborated clinical grading, and ultrasound imaging indicated a trend in skin density improvement. The MSM was well-perceived.  Conclusion: The MSM is an efficacious and well-tolerated product for patients of all skin tones who desire a sheer, 100% mineral sunscreen moisturizer with anti-aging and skin health benefits. J Drugs Dermatol. 2024;23(7):538-544.  doi:10.36849/JDD.8082.

Ritlecitinib, a JAK3/TEC family kinase inhibitor, stabilizes active lesions and repigments stable lesions in vitiligo.

The efficacy of ritlecitinib, an oral JAK3/TEC family kinase inhibitor, on active and stable lesions was evaluated in patients with active non-segmental vitiligo in a phase 2b trial (NCT03715829). Patients were randomized to placebo or daily ritlecitinib 50 mg (with or without 4-week 100-mg or 200-mg loading dose), 30 mg, or 10 mg for 24 weeks. Active lesions showed greater baseline expression of inflammatory/immune markers IFNG and CCL5, levels of CD103, and T-cell infiltrates than stable lesions. Patients with more active than stable vitiligo lesions showed higher baseline serum levels of CXCL9 and PD-L1, while patients with more stable than active lesions showed higher baseline serum levels of HO-1. At Week 24, ritlecitinib 50 mg significantly stabilized mean percent change from baseline in depigmentation extent in both active lesions and stable lesions vs. placebo-response, with stable lesions showing greater repigmentation. After 24 weeks of treatment, ritlecitinib 50 mg increased expression of melanocyte markers in stable lesions, while Th1/Th2-related and co-stimulatory molecules decreased significantly in both stable and active lesions. Serum from patients with more active than stable lesions showed decreased levels of ICOS and NK cell activation markers. These data, confirmed at transcription/protein levels, indicate that stable lesion repigmentation occurs early with ritlecitinib, while active lesions require stabilization of inflammation first. ClinicalTrials.gov: NCT03715829.

Drug-Induced Pigmentation: A Review.

Drug-induced pigmentation (DIP) is estimated to account for 20% of all cases of acquired hyperpigmentation. Over 50 agents have been implicated, including antibiotics, antimalarials, antiretrovirals, antipsychotics, prostaglandin analogs, heavy metals, and chemotherapeutic agents. The skin, mucosal surfaces, nails, and hair can all be affected, with the color, distribution, onset, and duration of pigmentation varying between offending agents. Both a thorough physical examination and medication history are necessary to determine the offending agent. In terms of mechanism, DIP occurs most frequently through the accumulation of melanin within the dermis but also by drug accumulation, pigment synthesis, and iron deposition. Photoprotection, including applying a broad-spectrum sunscreen, wearing photoprotective clothing, and seeking shade, plays an important role in the prevention of exacerbation of DIP. Multiple lasers, including the picosecond alexandrite, Q-switched Nd:YAG, Q-switched alexandrite, and Q-switched ruby lasers, have been successful in obtaining clearance of DIP. In this review, we examine the unique characteristics of each of the inciting agents in terms of incidence, clinical presentation, time to onset and resolution, and pathogenesis.

Antiaging, Brightening, and Antioxidant Efficacy of Fermented Bilberry Extract (Vaccinium myrtillus): A Randomized, Double-Blind, Placebo-Controlled Trial.

Strategies for successful aging, including the use of food supplements, are part of the approach to support skin youthfulness. To demonstrate the efficacy of fermented bilberry extract (FBE) against skin aging and uneven complexion, a clinical trial was carried out on 66 subjects with visible "crow's feet" wrinkles, mild-to-moderate skin slackness, and uneven skin tone. The wrinkle depth, skin smoothness (Ra) and roughness (Rz), skin firmness (R0) and elasticity (R2), skin coloration (ITA°), and skin antioxidant capacity were measured before and after 28 (D28), 56 (D56), and 84 (D84) days of product use (either FBE or a placebo). These parameters were also integrated with a clinical evaluation, carried out by a dermatologist, and a self-assessment questionnaire to align the measured efficacy with the visual or perceived efficacy. At D84, the wrinkle depth had decreased by 10.6%, Ra had improved by 7.9%, Rz had decreased by 7.3%, R0 had improved by 13.3%, R2 had improved by 12.4%, and skin antioxidant capacity had increased by 20.8%. ITA° increased by 20.8% and was accompanied by a decrease in the skin's redness component by 16.8% and an increase in the lightness component by 2.2%. The variation of all the above-mentioned parameters was statistically significant between the FBE and PL groups. Our findings demonstrate the efficacy of FBE in improving skin aging and complexion evenness.

Phenylalanine Butyramide: A Butyrate Derivative as a Novel Inhibitor of Tyrosinase.

Metabolites resulting from the bacterial fermentation of dietary fibers, such as short-chain fatty acids, especially butyrate, play important roles in maintaining gut health and regulating various biological effects in the skin. However, butyrate is underutilized due to its unpleasant odor. To circumvent this organoleptic unfavorable property, phenylalanine butyramide (PBA), a butyrate precursor, has been synthesized and is currently available on the market. We evaluated the inhibition of mushroom tyrosinase by butyrate and PBA through in vitro assays, finding IC50 values of 34.7 mM and 120.3 mM, respectively. Docking calculations using a homology model of human tyrosinase identified a putative binding mode of PBA into the catalytic site. The anti-aging and anti-spot efficacy of topical PBA was evaluated in a randomized, double-blind, parallel-arm, placebo-controlled clinical trial involving 43 women affected by photo-damage. The results of this study showed that PBA significantly improved skin conditions compared to the placebo and was well tolerated. Specifically, PBA demonstrated strong skin depigmenting activity on both UV and brown spots (UV: -12.7% and -9.9%, Bs: -20.8% and -17.7% after 15 and 30 days, respectively, p < 0.001). Moreover, PBA brightened and lightened the skin (ITA°: +12% and 13% after 15 and 30 days, respectively, p < 0.001). Finally, PBA significantly improved skin elasticity (Ua/Uf: +12.4% and +32.3% after 15 and 30 days, respectively, p < 0.001) and firmness (Uf: -3.2% and -14.9% after 15 and 30 days, respectively, p < 0.01).

Journey through the spectacular landscape of melanocortin 1 receptor.

The physiological role of α-melanocyte stimulating hormone in regulating integumental pigmentation of many vertebrate species has been recognized since the 1960's. However, its physiological significance for human pigmentation remained enigmatic until the 1990's. α-Melanocyte stimulating hormone and related melanocortins are synthesized locally in the skin, primarily by keratinocytes, in addition to the pituitary gland, and therefore act as paracrine factors for melanocytes. Human melanocytes express the melanocortin 1 receptor, which recognizes α-melanocyte stimulating hormone and the related adrenocorticotropic hormone as agonists. This review summarizes the current knowledge of the pleotropic effects of the activated melanocortin 1 receptor that maintain human melanocyte homeostasis by regulating melanogenesis and the response to environmental stressors, mainly solar radiation. Certain allelic variants of the melanocortin 1 receptor gene are associated with specific pigmentary phenotypes in various human populations. Variants associated with red hair phenotype compromise the function of the encoded receptor. Activation of the human melanocortin 1 receptor regulates eumelanin synthesis and enhances DNA damage response of melanocytes to solar radiation and oxidative stressors. We describe how synthetic selective melanocortin 1 receptor agonists can be efficacious as sunless tanning agents, for treatment of vitiligo and photosensitivity disorders, and for prevention of skin cancer, including melanoma.